volume II
system
descriptions
ANALYSIS OF
AND COSTS
Of
RETROFIT EMISSION
CONTROL SYSTEMS
for
USED MOTOR
Environmental Protection Agency
MAY 1972
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volume II
system
descriptions
ANALYSIS OF
AND COSTS
of
RETROFIT EMISSION
CONTROL SYSTEMS
for
USED MOTOR
prepared under
EPA Contract 68-04-0038
by
Olson Laboratories, Inc.
500 East Orangethorpe Avenue
Anaheim, California 92801
In Association With Northrop Corporation
Report 71Y233
MAY 1972
for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air Programs
Division of Emission Control Technology
2565 Plymouth Road
Ann Arbor, Michigan 48105
Approved by:
0. D. Foulds
Vice President
Olson Laboratories, Inc.
-------
FOREWORD
The Environmental Protection Agency, as Administrator of the Clean Air Amendments
Act of 1970, is required to assist States and air pollution control agencies in
meeting national ambient air quality standards and mobile or stationary source
emission standards, by issuing information on control techniques. Contract
68-04-0038 was performed with the Office of Air Programs, Division of Emission Con-
trol Technology, to determine what emission control techniques are feasible for
retrofit to used cars, considering emission reduction effectiveness, costs, effect
on vehicle performance, and the facilities and labor skills required for retrofit
device installation and eventual maintenance and inspection. This report documents
the results obtained, the pertinent data upon which the results are based, the
techniques of test and analysis, and the recommendations for future programs
to implement the results. The report consists of the following six volumes:
I. Program Summary: Highlights the principal program results and
conclusions as to the overall feasibility of retrofit methods for
vehicle emission control. Provides guidelines for the evaluation of
retrofit approaches and the implementation of control programs.
II. System Descriptions: Documents the physical, functional, and
performance characteristics of the candidate retrofit methods and
their installation requirements and costs.
III. Performance Analysis: Documents the relative effectiveness and costs
of retrofit methods, the techniques of analysis and testing, and the
assumptions and rationale upon which the analysis was based.
IV. Test and Analytical Procedures: Documents the approach to the overall
program objectives and the tasks and procedures implemented to meet
the objectives.
V. Appendices: Documents the raw data obtained from retrofit development
sources and data of overall applicability to the report.
VI. Addendum for Durability Tests: Documents the results of 25,000-mile
durability tests on four representative retrofit devices.
iii
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PREFACE
The system descriptions presented in this document were prepared
using data either obtained from the retrofit device development
sources or developed through test and analysis as part of the study
effort. In many cases the onJLy data used were those provided by
the retrofit sources, since the study schedule and the large num-
ber of devices found to exist did not permit data development to
be perj^rmed for each device. The presentation of developer data
does not mean that the study contractor agrees with or supports
the concepts or rationale expressed or implied in such data.
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ACKNOWLEDGMENTS
This program was conducted under the direction and with the assistance
of Dr. Jose L. Bascunana, Project Officer of the Environmental Protec-
tion Agency, Emission Control Technology, Inc., provided the method-
ology for performance analysis under a subcontract agreement with
Olson Laboratories, Inc.
The accomplishment of this program was made possible by the cooperation
and assistance of the many developers and manufacturers of retrofit
devices. Their contribution of coordination time, data, and retrofit
device hardware is very much appreciated.
vii
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GLOSSARY
AMA Automobile Manufacturers Association
CEI Cost Effectiveness Index
CI Cost Index
CID Cubic Inch Displacement
CNG Compressed natural gas
CO Carbon monoxide
CVS Constant volume sampling
DI Driveability Index
EGR Exhaust gas recirculation
El Emission Index
EPA Environmental Protection Agency
GM/MI Grams per mile
HC Hydrocarbons
LNG Liquified natural gas
LPG Liquified petroleum gas
MMBM Mean-miles-before-maintenance
MMBPF Mean-miles-before-partial-failure
MMBTF Mean-miles-before-total-failure
MPH Miles per hour
MPG Miles per gallon
MTTM Mean-time-to-maintain
MTTR Mean-time-to-repair
NDIR Nondispersive infrared
NOx Oxides of nitrogen
OEM Original equipment
PCV Positive crankcase ventilation
PI Performance Index
PPM Parts per million
WOT Wide open throttle
viii
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VOLUME II
CONTENTS
Section Page
FOREWORD iii
PREFACE v
ACKNOWLEDGMENTS vii
GLOSSARY viii
1 INTRODUCTION 1-1
1.1 Definition of Retrofit Method and Light Duty
Vehicle 1-1
1.2 Retrofit Method Classification System 1-2
1.3 Data Search and Development Requirements 1-3
1.4 System Description Approach 1-4
1.5 Data Survey Results 1-6
2 RETROFIT EMISSION CONTROL TECHNOLOGY 2-1
2.1 Pollutants Attributable to Gasoline- and Gaseous-
Fueled Vehicles 2-1
2.2 Vehicle Sources of HC, CO and NOx 2-1
2.3 Principles of Retrofit Methods for Controlling
Vehicle Emissions 2-2
2.3.1 Exhaust Emission Control Systems - Group 1 2-2
2.3.2 Crankcase Emission Control Systems - Group 2 .... 2-9
2.3.3 Evaporative Emission Control Systems - Group 3 ... 2-10
3 GROUP 1 RETROFIT METHOD DESCRIPTIONS: TYPE 1.1 - EXHAUST
GAS CONTROL SYSTEMS 3-1
3.1 Catalytic Converters - Retrofit Subtype 1.1.1 ... 3-3
3.1.1 Device 96: Catalytic Converter with Distributor
Vacuum Advance Disconnect 3-3
3.1.2 Device 292: Catalytic Converter 3-19
3.1.3 Device 62: Catalytic Converter 3-26
3.1.4 Device 93: Catalytic Converter with Exhaust Gas
Recirculation, Spark Modification, and Lean
Idle Mixture 3-29
3.2 Thermal Reactor - Retrofit Subtype 1.1.2 3-31
3.2.1 Device 244: Rich Thermal Reactor 3-31
3.2.2 Device 463: Rich Thermal Reactor with Exhaust Gas
Recirculation and Spark Retard 3-51
3.2.3 Device 468: Lean Thermal Reactor with Exhaust Gas
Recirculation , 3-58
3.2.4 Device 31: Thermal Reaction by Turbine Blower Air
Injection 3-64
3.3 Exhaust Gas Afterburner - Retrofit Subtype 1.1.3 . „ 3-73
3.3.1 Device 308: Exhaust Gas Afterburner . 3-73
3.3.2 Device 425: Exhaust Gas Afterburner 3-79
IX
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CONTENTS (CONTINUED)
Section
3.4 Exhaust Gas Filter - Retrofit Subtype 1.1.4 .... 3-89
3.4.1 Device 164: Exhaust Gas Filter 3-89
3.5 Exhaust Gas Backpressure Control - Retrofit Sub-
type 1.1.5 3-95
3.5.1 Device 322; Exhaust Gas Backpressure Valve 3-95
4 GROUP 1 RETROFIT METHOD DESCRIPTIONS: TYPE 1.2 - INDUCTION
CONTROL SYSTEMS 4-1
4.1 Air Bleed to Intake Manifold - Retrofit Subtype
1.2.1 4-3
4.1.1 Device 1: Air Bleed to Intake Manifold 4-3
4.1.2 Device 42; Air Bleed to Intake Manifold 4-14
4.1.3 Device 57: Air Bleed with Exhaust Gas Recircula-
tion and Vacuum Advance Disconnect 4-22
4.1,4 Device 325/433: Air Vapor Bleed to Intake
Manifold 4-30
4.1.5 Device 401: Air-Vapor Bleed to Intake Manifold . . . 4-39
4.1.6 Device 418: Air Bleed to Intake Manifold 4-43
4,1.7 Device 458: Air Bleed to Intake Manifold 4-45
4,1.8 Device 462: Air Bleed to Intake and Exhaust
Manifolds 4-46
4.2 Exhaust Gas Recirculation - Retrofit Subtype 1.2.2 . 4-49
4.2.1 Device 10: Throttle-Controlled Exhaust Gas Recir-
culation with Vacuum Advance Disconnect 4-50
4.2.2 Device 245: Variable Camshaft Timing 4-58
4.2.3 Device 246: Speed-Controlled Exhaust Gas Recircu-
lation with Vacuum Advance Disconnect 4-67
4.2.4 Device 294: Exhaust Gas Recirculation with
Carburetor Modification 4-79
4.3 Intake Manifold Modification - Retrofit Sub-
type 1.2.3 4-80
4.3.1 Device 172: Intake Manifold Modification 4-80
4.3.2 Device 430: Induction Modification 4-86
4.3.3 Device 440: Intake Deflection Plate 4-91
4.3.4 Device 384: Air-Fuel Mixture Diffuser 4-97
4.4 Carburetor Modification - Retrofit Subtype 1.2.4 • • 4-103
4.4.1 Device 33: Carburetor Modification, Main Jet
Differential Pressure 4-104
4.4.2 Device 56: Crankcase Blowby and Idle Air Bleed
Modification 4-112
4.4.3 Device 288: Carburetor Main Discharge Nozzle
Modification 4-117
4.4.4 Device 295: Variable Venturi Carburetor 4-123
4.4.5 Device 317: Carburetor Modification with Vacuum
Advance Disconnect 4-132
4.5 Turbocharged Engine - Retrofit Subtype 1.2.5 .... 4-139
4.5.1 Device 100: Turbocharger 4-139
4.6 Fuel Injection - Retrofit Subtype 1.2.6 4-141
4.6.1 Device 22: Electronic Fuel Injection 4-141
x
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CONTENTS (CONTINUED)
Section
5 GROUP 1 RETROFIT METHOD DESCRIPTIONS: TYPE 1.3 -
IGNITION CONTROL SYSTEMS 5-1
5.1 Ignition Timing Modification - Retrofit Subtype
1.3.1 5-3
5.1.1 Device 69: Electronic-Controlled Vacuum Advance
Disconnect and Carburetor Lean Idle Modification . 5-3
5.1.2 Device 175: Ignition Timing Modification with
Lean Idle Adjustment 5-12
5.2 Ignition Spark Modification - Retrofit Subtype
1.3.2 5-21
5.2.1 Device 23: Electronic Ignition Unit 5-22
5.2.2 Device 95: Ignition Spark Modification 5-23
5.2.3 Device 259: Photocell-Controlled Ignition System . . 5-25
5.2.4 Device 268: Capacitive Discharge Ignition 5-32
5.2.5 Device 296: Ignition Timing and Spark Modification . 5-36
6 GROUP 1 RETROFIT METHOD DESCRIPTIONS: TYPE 1.4 -
FUEL MODIFICATION 6-1
6.1 Gas Conversion - Retrofit Subtype 1.4.1 6-1
6.1.1 Device 52: LPG Conversion 6-5
6.1.2 Device 466: LPG-Gasoline Dual-Fuel Conversion . . . 6-31
6.1.3 Device 459: LPG Conversion with Deceleration Unit. . 6-35
6.1.4 Device 461: LPG Conversion with Exhaust Reactor
Pulse Air Injection and Exhaust Gas Recirculation. 6-40
6.1.5 Device 464: Methanol Fuel Conversion with Catalytic
Converter 6-43
6.1,6 Device 460: Compressed Natural Gas Dual-Fuel
Conversion 6-47
6.2 Fuel Additive - Retrofit Subtype 1.4.2 6-61
6.2.1 Device 182: Fuel and Oil Additives 6-61
6.2.2 Device 465: Fuel Additive 6-66
6.2.3 Device 282: LP Gas Injector 6-67
6.2.4 Device 457: Water Injection 6-73
6.3 Fuel Conditioner - Retrofit Subtype 1.4.3 6-76
6.3.1 Device 36: Fuel Conditioning by Exposure to
Electromagnetic Field 6-76
6.3.2 Device 279: Fuel Activator 6-78
7 GROUP 2 RETROFIT METHOD DESCRIPTIONS CRANKCASE EMISSION
CONTROL SYSTEMS 7-1
7.1 Closed System - Retrofit Type 2.1 7-3
7.1.1 Device 24: Heavy Duty Positive Crankcase
Control Valve with Air Bleed 7-3
7.1.2 Device 170: Closed Blowby Control System 7-7
7.1.3 Device 315: Closed Blowby Control System 7-15
xi
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CONTENTS (CONTINUED)
Section Page
7.2 . Open Systems - Retrofit Type 2.2 . . . 7-21
7.2.1 Device 160; Closed or Open Blowby Control System . . 7-21
7.2.2 Device 427: Closed or Open Blowby Control System
with Filter 7-27
8 CROUP 3 RETROFIT METHOD DESCRIPTIONS EVAPORATIVE EMISSION
CONTROL SYSTEMS 8-1
8.1 Device 467 Absorption-Regenerative Fuel
Evaporation Control System 8-3
8.1.1 ' Typical Installation Description 8-3
8.1.2 Typical Installation Initial and Recurring Cost . . 8-3
8.1.3 Feasibility Summary 8-3
9 GROUP 4 RETROFIT METHOD DESCRIPTIONS EMISSION CONTROL
COMBINATIONS 9-1
9fl Device 59: Three-Stage Exhaust Gas Control System . 9-1
9.1.1 Physical Description 9-2
9.1.2 Functional Description 9-2
9.1.3 Performance Characteristics 9-2
9.1.4 Reliability 9-2
9.1.5 Maintainability 9-2
9.1.6 Driveability and Safety 9-2
9.1.7 Installation Description 9-3
9.1.8 Initial and Recurring Costs 9-3
9f1.9 Feasibility Summary 9-3
9.2 Device 165: Exhaust Gas Afterburner/Recirculation
with Blowby and Fuel Evaporation Recirculation . . 9-5
9.2,1 Physical Description 9-5
9.2.2 Functional Description 9-6
9.2.3 Performance Characteristics 9-7
.9.2.4 Reliability 9-8
9.2.5 Maintainability 9-9
9.2.6 Driveability and Safety 9-9
9.2.7 Installation Description 9-9
9.2.8 Initial and Recurring Costs 9-10
9.2.9 Feasibility Summary 9-10
9.3 Device 408: Exhaust Gas and Blowby Recirculation
with Intake Vacuum Control and Turbulent Mixing . 9-15
9.3,1 Physical Description 9-15
9.3.2 Functional Description 9-15
9.3.3 Performance Characteristics ... 9-17
9.3.4 Reliability 9-17
9.3.5 Maintainability 9-17
9.3.6 Driveability and Safety 9-17
9.3.7 Installation Description 9-17
9.3.8 Initial and Recurring Costs 9-18
9.3.9 Feasibility Summary 9-18
xii
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CONTENTS (CONTINUED)
Section
9.4 Device 469: Thermal Reactor with Exhaust Gas Recir-
culation and Particulate Control 9-21
9.4.1 Physical Description 9-21
9.4.2 Functional Description 9-21
9.4.3 Performance Characteristics 9-23
9.4.4 Reliability 9-24
9.4.5 Maintainability 9-25
9.4.6 Driveability and Safety 9-25
9.4.7 Installation Description 9-25
9.4.8 Initial and Recurring Costs 9-26
9.4.9 Feasibility Summary 9-26
10 REFERENCES 10-1
11 RETROFIT DEVICE INDEX 11-1
ILLUSTRATIONS
Page
2-1 Effects of Air-Fuel Ratio (Reference 114) 2-7
3-1 Device 96 Catalytic Converter Configuration Tested in
Retrofit Program - Development Model 3-4
3-2 Device 96 Catalytic Converter with Vacuum Advance Disconnect
Installation 3-5
3-3 Device 96 Catalytic Converter with Vacuum Advance Disconnect
Functional Diagram 3-7
3-4 Typical Device 292 Configuration for LPG-Fuel Material
Handling Vehicle (Reference 12) 3-19
3-5 Device 292 Configuration for Gasoline Engine (Reference 12). . 3-19
3-6 Device 292 LPG Configuration Catalytic Converter Functional
Diagram (Reference 12) 3-20
3^-7 Device 292 Catalytic Converter Light Duty Vehicle Develop-
mental Configuration (Reference 12) 3-24
3-8 Device 62 Catalytic Converter Emission Reduction Performance
Versus Catalyst Temperature (Reference 8) 3-27
3-9 Device 244 Type V Thermal Reactor Physical Configuration
(Reference 72) 3-32
3-10 Device 244 Exhaust Gas Flow Through Rich Thermal Reactor
(Reference 71) 3-34
3-11 Device 244 Rich Thermal Reactor and Intake Manifold Heat
Interface (Reference 71) 3-36
3-12 Device 244 Rich Thermal Reactor Exhaust Port Insert
Alternative Configurations (Reference 71) 3-38
3-13 Device 244 Rich Thermal Reactor Emission Reduction Charac-
teristics Compared to Standard Air Injection (Reference 71). 3-39
xiii
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ILLUSTRATIONS (CONTINUED)
Device 244 Rich Thermal Reactor Temperature Profile for
One 7-Mode Cycle (Reference 71) 3-39
Effect of Fuel Variables on Average Thickness Losses of OR-1
Alloy During Continuous Thermal Cycling (Reference 2) ... 3-41
Device 244 Rich Thermal Reactor Core Equilibrium Tempera-
tures for Vehicle Operating Modes (Reference 71) 3-42
Condition of Device 244 Rich Thermal Reactor Components
After One Hour of Light-Off (Reference 71) 3-43
Device 244 Thermal Reactor Installation (Reference 72) .... 3-47
Device 463 Rich Thermal Reactor Model II Configuration
(Reference 101) 3-51
3^20 Effect of Flame Holders on Device 463 Rich Thermal Reactor
Warmup Time During 1968 Federal Test Procedure (Refer-
ence 101) 3-53
3-21 Device 463 Rich Thermal Reactor Installation on 1971 Ford
LTD 351-CID Engine (Reference 101) 3-56
3^-22 Device 31 Turbine Blower Configuration (Developer Photo) . . . 3-64
3-23 Device 31 Air Injection System Configuration (Developer
Sketch) 3-65
3-24 Device 31 Turbine Blower Air Pumping Characteristics
(Developer Data) 3^-66
3-25 Device 31 Turbine Blower Output as Percent of Engine Inlet
Airflow (Developer Data) 3-66
3-26 Device 31 Turbine Blower Emission Test Comparison with
Conventional Air Pump System (Developer Data) 3-68
3-27 Device 31 Turbine Blower Air Injection System Installation
(Developer Photo) 3-71
3-28 Device 308 Exhaust Gas Afterburner Showing Spark Plug (Right
Side) and Diametrically Opposed Electrode (Left Side) . . . 3-74
3-29 Device 425 Exhaust Gas Afterburner (U.S. Patent No.
3,601,982) 3-80
3-30 Device 164 Exhaust Gas Filter Components (Developer
Photograph) 3-89
3-31 Device 164 Exhaust Gas Filter Functional Schematic 3-90
4-1 Device 1 Air Bleed Components 4-4
4-2 Device 1 - Functional Schematic Diagram 4-5
4-3 Device 1 Air Bleed to Intake Manifold Typical Installation
(Developer Sketch) 4-12
4-4 Device 42: Air Bleed to Intake Manifold 4-14
4-5 Device 42 Air Bleed to Intake Manifold Functional Schematic
(Developer Diagram) .„ 4-15
4-6 Device 42 Air Bleed to Intake Manifold: Typical Installation
of Air Valve on Carburetor Air Cleaner (Developer Photo) . . 4-19
4-7 Device 57 Air Bleed with EGR and Vacuum Advance Disconnect
System Components .... 4-22
4-8 Device 57 Air Bleed with EGR and Vacuum Advance Disconnect
Installed on V-8 Intake Manifold (Developer Photo) 4-26
4-9 Device 325/433 Air-Vapor Bleed to Intake Manifold System
Components > 4-31
xiv
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ILLUSTRATIONS (CONTINUED)
Page
Device 325/433 Air Injection Needles 4-31
Device 325/433 Air-Vapor Bleed to Intake Manifold Func-
tional Schematic (Developer Diagram) 4-32
Device 325/433 Air Needle System Compared to Standard Needle
(Developer Diagram) 4-33
Device 401 Air-Vapor Bleed to Intake Manifold System
Configuration (Developer Diagram) ..... 4-39
Device 462 Air Bleed to Intake and Exhaust Manifolds Func-
tional and Installation Schematics (Reference 90) 4-47
Device 10 Throttle-Controlled EGR with Vacuum Advance
Disconnect System Configuration 4-51
Device 245 Variable Camshaft Timing Gear 4-58
Device 245 Variable Camshaft Installation 4-63
Device 246 Speed-Controlled EGR with Vacuum Advance
Disconnect System Components ..... 4-68
Device 246 Speed-Controlled EGR with Vacuum Advance Dis-
connect Functional Schematic (Developer's Diagram) 4-68
Device 246 Speed-Controlled EGR with Vacuum Advance Dis-
connect Installation (Developer Sketch) 4-77
Device 246 Typical Installation on Retrofit Program Test
Vehicle 4-77
Device 172 Intake Manifold Modification (Developer Sketch) . . 4-81
Device 430 Intake Manifold Nozzle Screen Configuration .... 4-86
Device 430 Intake Manifold Nozzle Screen Installation .... 4-87
Device 440 Intake Deflection Plate Vehicle Manufacturer
Configurations 4-92
Device 440 Intake Deflection Plate Installed and Typical
Variations (Developer Sketch) 4-92
Device 384 Air-Fuel Mixture Diffuser (Configuration for
Two-Barrel Carburetor) 4-97
Device 384 Air-Fuel Mixture Diffuser Installation Sketch
(from Developer's Patent Disclosure) 4-99
Device 33 Carburetor Modification (Main Jet Differential
Pressure) Configuration 4-104
Device 33 Carburetor Modification (Main Jet Differential
Pressure) Air-Fuel Ratio Test Results (Developer Data) . . . 4-106
Device 56 Crankcase Blowby and Idle Air Bleed Modification
(Developer Photo) 4-113
Device 56 Special Air Bleed Idle Jet 4-113
Device 288 Carburetor Main Discharge Nozzle Modification . . . 4-117
Device 295 Variable Venturi Carburetor 4-124
Device 295 Variable Venturi Carburetor Functional Diagram
(Developer Sketch) 4-125
Device 317 Carburetor Modification With Vacuum Advance
Disconnect Installation (Developer Photo) 4-133
Device 317 Carburetor Modification With Vacuum Advance
Disconnect; Principal Components (Developer Sketch) .... 4-134
xv
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ILLUSTRATIONS (CONTINUED)
Figure Page
5-1 Device 69 Electronic-Controlled Vacuum Advance Disconnect
with Carburetor Lean Idle Modification 5-5
5-2 Device 69 Electronic-Controlled Vacuum Advance Disconnect
Functional Schematic (Developer Sketch) 5-6
5-3 Device 175 Electronic Control Module Installed on Fender
Well 5-13
5-4 Device 259 Photocell-Controlled Ignition System Components
(4-Cylinder Ignition System) 5-25
5-5 Device 259 Photocell-Controlled Ignition System Electrical
Schematic (Developer Sketch) 5-27
5-6 Device 259 Photocell Controlled Ignition System Typical
Installation 5-29
5-7 Device 268 Capacitive Discharge Ignition 5-32
5-8 Device 268 Capacitive Discharge Ignition Schematic
(Developer Sketch) 5-33
5-9 Device 259 Ignition Timing and Spark Modification 5-37
6-1 Device 52 Gaseous Fuel Carburetor Types 6-6
6-2 Device 52 Single-Fuel System Diagram (Reference 35) 6-7
6-3 Device 52 Dual-Fuel System Diagram (Reference 36) 6-7
6-4 Device 52 Single-Fuel System Converter and Carburetor
Diagram (Reference 37) 6-9
6-5 Device 52 Dual-Fuel System Converter and Carburetor Diagram
(Reference 38) 6-9
6-6 Device 52 LPG Conversion Representative Carburetor
(Reference 37) 6-10
6-7 Device 52 Variation of Air-Fuel Ratio with Fuel Pressure
(Engine: Ford 352 CID with Type D - Reference 37) 6-11
6-8 Effect of Air-Fuel Ratio and Spark Advance on LPG
Emissions (Reference 41) 6-14
6-9 Device 52 Single-Fuel LPG Installation (Reference 52) .... 6-25
6-10 Device 459 LPG Conversion System Illustration (Reference 66) . 6-36
6-11 Device 459 Single-Fuel Air Valve Carburetor (Reference 66) . . 6-36
6-12 Device 460 Compressed Natural Gas Dual Fuel Conversion
System Installed on a Chrysler New Yorker (Reference 68) . . 6-49
6-13 CNG Instrument Panel Controls (Reference 103) 6-51
6-14 CNG Dual-Fuel Conversion System Functional Schematic
(Reference 46) 6-51
6-15 Device 282 LP Gas Injection System Components 6-68
6-16 Device 282 LP Gas Injection Functional Schematic 6-68
6-17 Device 279 Fuel Conditioner Functional Schematic (Developer
Data) 6-78
7-1 Device 24 System Components (Developer Drawing) 7-4
7^2 Device 170 Closed Blowby Control System (Developer Drawing). . 7-8
7-3 Device 170 Closed Blowby Control System Adjustable Blowby
Flow and Pressure Relief Valve (Developer Drawing) 7-8
7-4 Device 170 Closed Blowby Control System Adjustment Procedure . 7-12
7-5 Device 170 Closed Blowby Control System Installation
(Developer Photos) 7-12
7-6 Device 315 Closed Blowby Control System Installed on
Carburetor 7-16
xv i
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ILLUSTRATIONS (CONTINUED)
Figure Page
7-7 Device 315 Closed Blowby Control System Vent Valve
Configuration (Based on Developer Drawings) 7-16
7-8 Device 315 Slide Mechanism (Based on Developer Drawings) ... 7-17
7-9 Device 160 Closed System with Filter Typical Installation
(Developer Drawings) 7-21
7-10 Device 160 Closed Blowby Control System with Filter: PCV
Valve and Filter Assembly 7-22
7-11 Device 160 Oil-Bath Type Air Cleaner for Open Blowby
Systems (Developer Drawing) 7-22
7-12 Device 427 Closed Blowby Control System Filter-Valve
Assembly 7-27
7-13 Device 427 Closed Blowby Control System Filter-Valve
Assembly Details (Developer Drawing) .... 7-28
7-14 Device 427 Closed Blowby Control System with Filter
Functional Diagram (Developer Drawing) 7-28
8-1 Absorption-Regenerative Fuel Evaporation Control System . . . 8-2
9-1 Device 165 Exhaust Gas Afterburner/Recirculation with
Blowby and Fuel Evaporation Recirculation Installation . . . 9-6
9-2 Device 165 Exhaust Gas Afterburner/Recirculation with
Blowby and Fuel Evaporation Recirculation Functional
Block Diagram 9-7
9-3 Device 408 Exhaust Gas and Blowby Recirculation with Intake
Vacuum Control and Turbulent Mixing Assembly 9-16
9-4 Device 408 Exhaust Gas and Blowby Recirculation with Intake
Vacuum Control and Turbulent Mixing Components 9-16
9-5 Exhaust Gas Recirculation System 9-22
9-6 Exhaust Particulate Matter Trapping System A 9-22
9-7 Cyclone Separator and Collection Box 9-23
xvii
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TABLES
1-1 Type of Vehicle Emission Controls Incorporated on Existing
"Used Cars" at Time of Manufacture 1-3
1-2 Data Survey Results 1-8
2-1 Classification of Retrofit Methods 2-3
3-1 Type 1.1 - Exhaust Gas Control System Retrofit Devices .... 3-2
3-2 Device 96 Catalytic Converter with Vacuum Advance Disconnect
Emission Reduction and Fuel Consumption Performance .... 3-8
3-3 Device 96 Average Emission Reduction Performance 3-8
3-4 Device 96 Emission Reduction Performance Reported by
Developer 3-9
3-5 Emission Test Results Obtained by EPA on Tricomponent Cata-
lytic Converter Provided by Device 96 Developer 3-10
3-6 . Device 96 Catalytic Converter with Vacuum Advance Disconnect
Driveability Test Results 3-13
3-7 Device 96 Catalytic Converter with Vacuum Advance Disconnect
Installation Procedure 3-15
3-8 Device 96 Catalytic Converter with Vacuum Advance Disconnect
Initial and Recurring Costs 3-18
3-9 Device 292 LPG-Fuel Emission Reduction Performance Reported
by Developer 3-21
3-10 Device 292 Catalytic Converter EPA Emission Test Results with
Auxiliary Air Pump 3-21
3-11 Device 292 Catalytic Converter Emission Reduction Reliability
Reported by Developer for 48,300 Miles of Operation .... 3-22
3-12 Device 292 Catalytic Converter Installation Procedure .... 3-24
3-13 Device 292 Catalytic Converter Initial and Recurring Costs . . 3-25
3-14 Device 62 Catalytic Converter EPA Emission Test Results . . . 3-27
3-15 Device 93 Catalytic Converter with Exhaust Gas Recirculation,
Spark Modification, and Lean Idle Mixture EPA Emission
Test Results 3-30
3-16 Composition of Candidate Alloys for Device 244 Rich Thermal
Reactor 3-34
3-17 Device 244 Rich Thermal Reactor Developer Acceleration Test
Results 3-45
3-18 Device 244 Rich Thermal Reactor Developer Fuel Consumption
Test Results 3-46
3-19 Device 244 Rich Thermal Reactor Installation Procedure .... 3-48
3-20 Device 244 Rich Thermal Reactor Initial and Recurring Costs . 3-49
3-21 Device 463 Rich Thermal Reactor Emission Levels Compared to
1975 Standards 3-54
3-22 Device 463 Rich Thermal Reactor Emission Levels Reported by
EPA 3-54
3-23 Device 463 Rich Thermal Reactor Exhaust Backpressure Reported
by Developer 3-55
3-24 Device 463 Rich Thermal Reactor Vehicle Acceleration Time
Increase Reported by Developer 3-55
XVlll
-------
TABLES (CONTINUED)
Table
3-25 Device 468 Emission Test Results without Air Injection .... 3-60
3-26 Device 468 Emission Test Results with Air Injection 3-60
3-27 Device 468 LTR-EGR Durability Emission Test Results 3-61
3-28 Device 468 LTR-EGR Fuel Consumption Compared to Conventional
Cars 3-63
3-29 Device 31 Turbine Blower and Conventional Air Pump System
Emission Test Results (Developer 7-Mode Data) 3-67
3-30 Device 31 Turbine Blower Air Injection System Installation
Procedure 3-70
3-31 Device 31 Turbine Blower Air Injection System Initial and
Recurring Costs 3-72
3-32 Device 308 Exhaust Gas Afterburner Emission Test Results
Reported by Developer 3-75
3-33 Device 308 Exhaust Gas Afterburner Installation Procedure . . 3-77
3-34 Device 308 Exhaust Gas Afterburner Initial and Recurring Costs 3-78
3-35 Device 425 Exhaust Gas Afterburner Emission Test Results
Reported by Developer 3-81
3-36 Device 425 Exhaust Gas Afterburner Installation Procedure . . 3-85
3-37 Device 425 Exhaust Gas Afterburner Initial and Recurring Costs 3-86
3-38 Device 164 Exhaust Gas Filter Emission Test Results Reported
by the Developer 3-91
3-39 Device 164 Exhaust Gas Filter Installation Procedure 3-92
3-40 Device 164 Exhaust Gas Filter Initial and Recurring Costs . . 3-93
3-41 Device 322 Exhaust Gas Backpressure Valve Emission Test
Results 3-95
4-1 Type 1.2 Induction Control System Retrofit Devices 4-2
4-2 Device 1 Air Bleed to Intake Manifold Emission Results
Reported by Developer 4-6
4-3 Device 1 Air Bleed to Intake Manifold Emission Reduction and
Fuel Consumption Performance 4-7
4-4 Device 1 EPA Emission Test Results 4-8
4-5 Device 1 Air Bleed to Intake Manifold Driveability Test
Results 4-9
4-6 Device 1 Air Bleed to Intake Manifold Installation Procedure . 4-10
4-7 Device 1 Air Bleed to Intake Manifold Initial and Recurring
Costs 4-13
4-8 Device 42 Air Bleed to Intake Manifold Emission Reduction and
Fuel Consumption Performance 4-17
4-9 Device 42 Mean Emission Test Results Based on Tests Reported
by Developer 4-17
4-10 Device 42 Air Bleed to Intake Manifold Driveability Test
Results 4-18
4-11 Device 42 Air Bleed to Intake Manifold Installation Procedure. 4-20
4-12 Device 42 Air Bleed to Intake Manifold Initial and Recurring
Costs 4-21
4-13 Device 57 Air Bleed with EGR and Vacuum Advance Disconnect
Emission Test Results Reported by Developer 4-25
4-14 Device 57 Air Bleed with EGR and Vacuum Advance Disconnect
Installation Procedure 4-27
xix
-------
TABLES (CONTINUED)
4-15 Device 57 Air Bleed with EGR and Vacuum Advance Disconnect
Initial and Recurring Costs 4-29
4-16 Device 325/433 Air-Vapor Bleed to Intake Manifold Emission
Test Results Provided by Developer 4-34
4-17 Device 325/433 Air-Vapor Bleed to Intake Manifold Average
Percentage Emission Reduction 4-35
4-18 Device 325/433 Air-Vapor Bleed to Intake Manifold Installation
Procedure 4-37
4-19 Device 325/433 Air-Vapor Bleed to Intake Manifold Initial and
Recurring Costs 4-38
4-20 Device 401 Air-Vapor Bleed to Intake Manifold Emission Test
Results Reported by Developer 4-40
4-21 Device 401 Air-Vapor Bleed to Intake Manifold Installation
Procedure 4-41
4-22 Device 401 Air-Vapor Bleed to Intake Manifold Initial and
Recurring Costs 4-42
4-23 Device 418 Air Bleed to Intake Manifold Mean Emission Test
Results 4-44
4-24 Device 458 Air Bleed to Intake Manifold Emission Test Results . 4-45
4-25 Device 462 Air Bleed to Intake and Exhaust Manifolds Mean
Emission Test Results 4-48
4-26 Device 10 Throttle-Controlled EGR with Vacuum Advance Dis-
connect Emission Reduction and Fuel Consumption Performance . 4-52
4-27 Device 10 Throttle-Controlled EGR with Vacuum Advance Dis-
connect Driveability Test Results 4-53
4-28 Device 10 Throttle-Controlled EGR with Vacuum Advance Dis-
connect Installation Procedure 4-55
4-29 Device 10 Throttle-Controlled EGR with Vacuum Advance Dis-
connect Initial and Recurring Costs 4-56
4-30 Device 245 Variable Camshaft Emission Reduction and Fuel Con-
sumption Performance 4-60
4-31 Comparative Emission Test Results for a Device Tested by EPA
with Variable Camshaft Timing, Vacuum Advance Disconnect and
Lean Carburetion 4-61
4-32 Device 245 Driveability Test Results 4-62
4-33 Device 245 Variable Camshaft Timing Installation Procedure . . 4-64
4-34 Device 245 Variable Camshaft Timing Initial and Recurring Costs 4-66
4-35 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Emission Reduction and Fuel Consumption Performance 4-70
4-36 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Emission Test Results Reported by Developer 4-71
4-37 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Emission Test Results Reported by EPA 4-72
4-38 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Driveability Test Results 4-73
4-39 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Installation Procedure 4-75
4-40 Device 246 Speed-Controlled EGR with Vacuum Advance Disconnect
Initial and Recurring Costs 4-78
xx
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TABLES (CONTINUED)
Table Page
4-41 Device 294 Emission Test Results 4-79
4-42 Device 172 Intake Manifold Modification Emission Test Results
Reported by Developer 4-82
4-43 Device 172 EPA Emission Test Results 4-82
4-44 Device 172 Intake Manifold Modification Fuel Consumption Data
Reported by Developer 4-83
4-45 Device 172 Intake Manifold Modification Installation Procedure. 4-84
4-46 Device 172 Intake Manifold Initial and Recurring Costs .... 4-85
4-47 Device 430 Induction Modification Emission Test Results Pro-
vided by Developer 4-88
4-48 Device 430 Induction Modification Installation Procedure . . . 4-89
4-49 Device 430 Induction Modification Initial and Recurring Costs . 4-90
4-50 Device 440 Intake Deflection Plate Test Experience Summary
Provided by Developer 4-93
4-51 Device 440 Intake Deflection Plate Installation Procedure . . . 4-95
4-52 Device 440 Intake Deflection Plate Initial and Recurring Costs. 4-96
4-53 Summary of Device 384 Air-Fuel Mixture Diffuser Exhaust
Emission Data Provided by Developer 4-100
4-54 Device 384 Air-Fuel Mixture Diffuser Installation Procedures. . 4-102
4-55 Device 33 Carburetor Modification (Main Jet Differential Pres-
sure) Emission Test Results Reported by Developer 4-107
4-56 Device 33 Carburetor Modification (Main Jet Differential Pres-
sure) Emission Reduction and Fuel Consumption Performance . . 4-107
4-57 Device 33 Carburetor Modification (Main Jet Differential
Pressure) 4-109
4-58 Device 33 Installation Procedure 4-109
4-59 Device 33 Initial and Recurring Costs 4-111
4-60 Device 56 Crankcase Blowby and Idle Air Bleed Modification:
Summary of Exhaust Emission Data Reported by Developer . . . 4-114
4-61 Device 56 Installation Procedure 4-115
4-62 Device 56 Initial and Recurring Costs 4-116
4-63 Device 288 Carburetor Main Discharge Nozzle Modification
Emission Reduction and Fuel Consumption Performance 4-118
4-64 Device 288 Summary of Developer-Reported Measurements by
Independent Laboratories 4-119
4-65 Device 288 Carburetor Main Discharge Nozzle Modification
Driveability Test Results 4-120
4-66 Device 288 Carburetor Main Discharge Nozzle Modification
Installation Procedure 4-121
4-67 Device 288 Carburetor Main Discharge Nozzle Modification
Initial and Recurring Costs 4-122
4-68 Device 295 Variable Venturi Carburetor Emission Reduction and
Fuel Consummation Performance 4-128
4-69 Device 295 Variable Venturi Carburetor Driveability Test
Results 4-129
4-70 Device 295 Variable Venturi Carburetor Installation Procedure . 4-130
4-71 Device 295 Variable Venturi Carburetor Initial and Recurring
Costs 4-131
4-72 Device 317 Emission Test Results Reported by Developer .... 4-135
xx i
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TABLES (CONTINUED)
Device 317 Carburetor Modification with Vacuum Advance Dis-
connect Installation Procedure 4-137
Device 317 Carburetor Modification with Vacuum Advance Dis-
connect Installation Costs 4-138
4-75 Device 100 Turbocharger Emission Test Results 4-139
4-76 Device 22 Electronic Fuel Injection Emission Test Results
Reported by EPA 4-141
4-77 Device 22 Electronic Fuel Injection Acceleration Results . . . 4-142
5-1 Type 1.3 Ignition Control System Retrofit Devices 5-1
5-2 Device 69 Electronic-Controlled Vacuum Advance Disconnect and
Carburetor Lean Idle Modification Emission Reduction and Fuel
Consumption Performance 5-7
5-3 Device 69 Driveability Test Results 5-8
5-4 Device 69 Electronic-Controlled Vacuum Advance Disconnect and
Carburetor Lean Idle Modification Installation Procedure . . 5-9
5-5 Device 69 Electronic-Controlled Vacuum Advance Disconnect and
Carburetor Lean Idle Modification Initial and Recurring Costs 5-11
5-6 Device 175 Ignition Timing Modification with Lean Idle Adjust-
ment Emission Test Results Submitted by Developer 5-14
5-7 Device 175 Ignition Timing Modification with Lean Idle Adjust-
ment Emission Reduction and Fuel Consumption Performance . . 5-15
5-8 Device 175 Driveability Test Results 5-17
5-9 Device 175 Installation Procedure 5-18
5-10 Device 175 Initial and Recurring Costs 5-19
5-11 Device 23 Electronic Ignition Unit Emission Test Results Re-
ported by HEW/NAPCA 5-22
5-12 Device 95 Ignition Spark Modification Emission Test Results . . 5-23
5-13 Device 95 Emission Test Results 5-24
5-14 Device 259 Photocell-Controlled Ignition System Installation
Procedure 5-30
5-15 Device 259 Photocell-Controlled Ignition System Initial and
Recurring Costs 5-31
5-16 Device 268 Capacitive Discharge Ignition Installation Procedure 5-34
5-17 Device 268 Capacitive Discharge Ignition Initial and Recurring
Costs 5-35
5-18 Device 296 Ignition Timing and Spark Modification Emission Test
Results Reported by Developer ..... 5-38
5-19 Device 296 Ignition Timing and Spark Modification Installation
Procedure 5-39
5-20 Device 296 Ignition Timing and Spark Modification Initial and
Recurring Costs 5-39
6-1 Type 1.4 Fuel Modification Retrofit Devices 6-2
6-2 Device 52 LPG Conversion Emission Test Results with 1968 Buick
Skylark 6-12
6-3 Device 52 LPG Conversion Emission Test Results with Vacuum
Advance Disconnect and Retarded Timing on 1970 Falcons and
Rebels 6-12
6-4 Device 52 Emission Test Results with Ford Fairlane and
Mustang 6-13
xxii
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TABLES (CONTINUED)
Cable Page
6-5 Device 52 LPG Conversion Emission Data Obtained by California
Gaseous Fuel Test Procedure 6-15
6-6 Device 52 LPG Conversion Vehicle Maintenance Cost
Comparison 6-17
6-7 Device 52 LPG Conversion Acceleration Test Results with Spark
Retard and Vacuum Advance Disconnected 6-18
6-8 Device 52 LPG Conversion Fuel Consumption Comparison 6-19
6-9 Device 52 LPG Conversion Installation Procedure 6-21
6-10 Device 52 LPG Conversion Initial and Recurring Costs for
Typical Conversion to Meet Emission Standards 6-26
6-11 Device 466 LPG Gasoline Dual-Fuel Conversion Emission Test
Results 6-32
6-12 Device 466 Exhaust Hydrocarbon Composition by Subtractive
Column Analysis 6-32
6-13 Device 466 Emission Test Results 6-33
6-14 Device 459 LPG Conversion with Deceleration Unit Emission Test
Results 6-37
6-15 Device 461 Emission Test Results 6-40
6-16 Device 464 Emission Test Results 6-44
6-17 Compressed Natural Gas Tank Characteristics 6-48
6-18 Device 460 Compressed Natural Gas Dual-Fuel Conversion Emission
Test Results 6-50
6-19 Device 460 CNG Dual-Fuel Conversion Emission Test Results . . . 6-52
6-20 Device 460 CNG Hydrocarbon Reactivity 6-52
6-21 Device 460 Acceleration Test Results with a 1971 Ford
Mustang 6-55
6-22 Device 460 CNG Dual-Fuel Conversion Initial and Recurring
Costs 6-57
6-23 Device 182 Fuel and Oil Additives Emission Test Results
Reported by City of Los Angeles 6-62
6-24 Device 182 Fuel and Oil Additives Emission Test Results
Reported by Olson Laboratories 6-62
6-25 Device 182 Fuel Consumption Reduction Reported by McDonnell
Douglas Aircraft Division 6-63
6-26 Device 182 Fuel and Oil Additives Initial and Recurring Costs . 6-64
6-27 Device 465 Emission Test Results 6-66
6-28 Device 282 LP Gas Injection Installation Procedure 6-71
6-29 Device 282 LP Gas Injection Initial and Recurring Costs .... 6-72
6-30 Device 36 Fuel Conditioning by Exposure to Electromagnetic Field
Emission Test Results 6-77
6-31 Device 279 Fuel Conditioner Emission Test Results Reported by
Developer 6-79
6-32 Device 279 Fuel Conditioner Installation Procedure 6-80
6-33 Device 279 Initial and Recurring Costs 6-81
7-1 Group 2 Crankcase Emission Control Systems 7-2
7-2 Device 24 Heavy Duty Positive Crankcase Control Valve with Air
Bleed Exhaust Emission Test Results Reported by EPA 7-4
7-3 Device 24 Heavy Duty Positive Crankcase Ventilation with Air
Bleed Initial and Recurring Costs 7-6
xxiii
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TABLES (CONTINUED)
Table
7-4 Device 170 Closed Blowby Control System Exhaust Emission Test
Results 7-10
7-5 Device 170 Closed Blowby Control System Installation
Procedure 7-13
7-6 Device 170 Closed Blowby Control System Initial and Recurring
Costs 7-14
7-7 Device 315 Closed Blowby Control System Exhaust Emission Test
Results Reported by Developer 7-18
7-8 Device 315 Closed Blowby Control System Installation
Procedure 7-19
7-9 Device 315 Closed Blowby Control System Initial and Recurring
Costs 7-20
7-10 Device 160 Closed or Open Blowby Control System with Filter
Emission Test Results Reported by Developer 7-23
7-11 Device 160 Closed Blowby Control System with Filter Installa-
tion Procedure 7-25
7-12 Device 160 Closed Blowby Control System with Filter Initial and
Recurring Costs 7-26
7-13 Device 427 Closed Blowby Control System with Filter Exhaust
Emission Reduction Performance 7-29
7-14 Device 427 Closed Blowby Control System with Filter Drive-
ability Results Reported by Developer 7-30
7-15 Device 427 Closed Blowby Control System with Filter Installa-
tion Procedure 7-32
7-16 Device 427 Closed Blowby Control System with Filter Initial
and Recurring Costs 7-33
8-1 Device 467 Absorption-Regenerative Fuel Evaporation Control
System Installation Procedure ..... 8-4
8-2 Device ^67 Absorption-Regenerative Fuel Evaporation Control
System Initial and Recurring Costs 8-5
9-1 Group 4 Emission Control Combination Retrofit Devices 9-1
9-2 Device 59 Three-Stage Exhaust Gas Control System Emission
Test Results 9-2
9-3 Device 59 Three-Stage Exhaust Gas Control System Driveability . 9-3
9-4 Device 165 Exhaust Gas Afterburner/Recirculation with Blowby
and Fuel Evaporation Recirculation Exhaust Emission Test
Results 9-8
9-5 Device 165 Exhaust Gas Afterburner/Recirculation with Blowby
and Fuel Evaporation Recirculation Driveability 9-9
9-6 Exhaust Gas Afterburner/Recirculation with Blowby and Fuel
Evaporation Recirculation Installation Procedure 9-11
9-7 Exhaust Gas Afterburner/Recirculation with Blowby and Fuel
Evaporation Recirculation Initial and Recurring Cost .... 9-13
9-8 Device 408 Exhaust Gas and Blowby Recirculation with Intake
Vacuum Control and Turbulent Mixing Driveability 9-18
9-9 Device 408 Exhaust Gas and Blowby Recirculation with Intake
Vacuum Control and Turbulent Mixing Installation
Procedure 9-19
xxiv
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TABLES (CONTINUED)
Table Page
9-10 Device 408 Exhaust Gas and Blowby Recirculation with Intake
Vacuum Control and Turbulent Mixing Initial and Recurring
Costs 9-20
9-11 Device 469 Emission Reduction Results Cold 9 Cycle CVS .... 9-24
XXV
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1 - INTRODUCTION
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SECTION .1
INTRODUCTION
A major objective of the retrofit study program was to gather and develop as much in-
formation as possible about emission control devices that are available for retrofit
to used cars. This volume describes 65 such devices to the level of detail possible
based on the data that could be obtained and developed within the study schedule.
The purpose of these descriptions is to show what retrofit devices exist, their con-
figurations and principles of operation, their performance characteristics, the cost
to the vehicle owner, and the skills and facilities required to install and maintain
the devices. This information will inform States and other agencies responsible for
implementing vehicle emission controls as to what devices are available for applica-
tion to their respective air quality control requirements. Within the retrofit
study itself, this information provided a basic source of quantitative input to the
performance analysis of retrofit devices presented in Volume III.
1.1 DEFINITION OF RETROFIT METHOD AND LIGHT DUTY VEHICLE
In the context of this study, "retrofit" means to equip those vehicles that were pro-
duced prior to the introduction of factory installed emission controls with emission
control systems which may or may not be similar to those installed on new model
vehicles. In this way, cars that are presently uncontrolled with respect to all or
some emissions could be brought under control.
A retrofit "method," "system," or "device," is defined as any mechanism, process, or
technique, except for regular vehicle maintenance, that may be added or applied to a
vehicle by modification or adjustment, to reduce vehicle emissions. To be a quali-
fied retrofit method, it must be within a reasonable range of size, complexity, and
cost; and must be founded on sound engineering principles for use on an uncontrolled
light-duty vehicle. In this report, the expressions "retrofit system" and "retrofit
device" are used synonomously. "Retrofit method" is used when referring to retrofit
systems or devices as a means of controlling used car emissions, as compared to
alternative methods such as periodic vehicle inspection.
The definition of "light-duty vehicle" as set forth by the Environmental Protection
Agency in the Code of Federal Regulations, Title 45, Chapter XII, Part 1201 (Refer-
ence 3), is as follows:
". . .any motor vehicle either designed primarily for
transportation of property and rated at 6,000 pounds
gross vehicle weight (GVW), or less, or designed
primarily for transportation of persons and having
a capacity of 12 persons or less."
1-1
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A further requirement of the study was that the vehicle have a reciprocating engine
which burns gasoline or a gaseous fuel; it was not within the scope of the study to
evaluate retrofit systems for diesel engines or engines of nonconventional configu-
ration such as the rotary or gas turbine engines.
The model years to which retrofit devices for emission control would be applicable
are pre-1973 vehicles which, for varying degrees and pollutants, are uncontrolled
for emissions. These vehicles are referred to in this report as a group by the
expression "used cars."
1.2 RETROFIT METHOD CLASSIFICATION SYSTEM
The sources of vehicle emissions provide the general structure of a system for
classifying retrofit devices. This general classification structure groups the
retrofit devices by emission source, as follows:
a. Exhaust emission control methods
b. Crankcase emission blowby control methods
c. Fuel evaporative emission control methods
d. Emission control combinations of the above.
These groups represent the encompassing generic categories of devices and are the
groups by which the devices were classified for study. Within each group, further
subordination of the classification system was made by allocating to each group,
according to related characteristics, retrofit types and subtypes. The detailed
classification structure is described in the next section (refer to Table 2-1)
Whereas the generic group level of classification is by emission source, the type
level is by physical location and functional interface of the control within the
vehicle. Where subtype classes are used, they represent specific control techniques,
such as catalytic converters, thermal reactors, or ignition timing modifications.
The study of the effectiveness and costs of retrofit methods for light-duty vehicle
emissions control excluded:
a. Regular vehicle maintenance
b. Engine tuneup
c. Inspection test programs, such as visual inspection, crankcase emissions
inspection test, idle emissions inspection test, and short-cycle emissions
inspection test.
d. The used car retrofit systems under development by General Motors Corpora-
tion, the Ford Motor Company, and the Chrysler Corporation.
By definition, the above, items a. through c., approaches to vehicle emission control
cannot be incorporated on a vehicle by retrofitting and therefore do not belong in
the retrofit classification. As required by the study contract, item d. was ex-
cluded so as not to duplicate other investigations.
Within the types of retrofit devices studied, the corresponding type of emission
control incorporated or to be incorporated on pre-1973 cars at the time of their
manufacture is shown in Table 1-1. These points of emission control incorporation
on a production line basis demarcate the vehicle populations to which the respective
1-2
-------
Table 1-1. TYPE OF VEHICLE EMISSION CONTROLS INCORPORATED ON
EXISTING "USED CARS" AT TIME OF MANUFACTURE
SOURCE OF
CONTROL
REQUIREMENT
Federal
California
MODEL YEAR OF CONTROL INITIATION
BLOWBY (HC)
1963
1961
EXHAUST
HC/CO NOx
1968 1973
1966 1971
EVAPORATIVE (HC)
1971
1970
retrofit types of control would be applicable. As indicated, long term effective-
ness of blowby controls, on a retrofit basis, is limited. Use of the vehicles to
which such controls would be applicable should be practically ended by 1973. This
does not preclude applying such controls as a means of hastening phaseout of these
early vehicle models. The vehicles most beneficial for retrofit applications are
those between 1963 and 1968 for exhaust control of hydrocarbon (HC) and carbon
monoxide (CO), between 1963 and 1973 for exhaust control of nitrogen oxides (NOx),
and between 1963 and 1971 for evaporative control of HC.
1.3 DATA SEARCH AND DEVELOPMENT REQUIREMENTS
To evaluate the effectiveness and costs of retrofit methods for light-duty vehicle
emission control, it was necessary to obtain or develop a set of data on each device
sufficient to evaluate each device on a total systems basis. This was necessary in
that any emission reduction benefit that a device might provide had to be evaluated
against the constraints that the use of the device might entail. For example,
vehicle driveability, safety, reliability, maintainability, initial cost, or recur-
ring (operating) costs could detract from the emission reduction benefits to such
an extent that the overall benefits would be less than those with the vehicle in its
uncontrolled state. .
The range of information required for each device included:
a.
A comprehensive description of the system or device and its operation., in-
cluding all significant facts relative to the purpose of the system and its
different components, with drawings and pictures as appropriate.
b. A description of the work required to install each retrofit system on
typical vehicles, including the facilities, amount of time, and labor skill
level required.
c. Identification of the maintenance and/or inspection required, with t'aa
frequency of such activity and details of inspection rejection criteria.
d. Emissions reduction for CO, HC, and NOx, with estimated errors, confidence
intervals and the test procedure, the vehicle model years of applicability,
and emission variation with mileage accumulation.
1-3
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e. Effect of the retrofit device on fuel type, fuel consumption, pollutant
emissions (other than CO, HC, and NOx such as particulates), driveability,
and safety.
f. Installation and operating costs incurred by the vehicle owner.
g. A discussion of the reliability and practicality of each retrofit device,
considering its usefulness for the future and the continuity of control it
would provide for modified or new emission standards.
h. A discussion of the relative effectiveness and costs of these retrofit de-
vices.
The data search was performed by first identifying all possible sources of informa-
tion from companies, individuals, and agencies engaged in research, development, or
production of retrofit devices. These sources included the Environmental Protection
Agency, the California Air Resources Board, Olson Laboratories, Incorporated, and
other Federal, State, and local air quality control agencies. The Society of Auto-
motive Engineers and the Air Pollution Control Association roster issues were also
used to identify prospective developers.
The identification of retrofit device sources was approached in three ways: a let-
ter of inquiry was sent to prospective sources of such information; a patent search
was conducted; and a news release announcing the program was sent to major news
media.
If an information source responded positively as a developer or producer of a retro-
fit device, a data questionnaire was sent, requesting details as to the emission re-
duction, driveability, reliability, maintainability, safety, installation, and cost
characteristics of the device.
1.4 SYSTEM DESCRIPTION APPROACH
Detailed system descriptions were prepared based on analysis of the data obtained
from the retrofit development sources and from the test program. The quantified
performance parameters derived through this evaluation were used as input to the
performance analysis of devices presented in Volume III.
The total characteristics of each retrofit system or device were brought under con-
sideration. The characteristics evaluated included the physical size, weight, shape,
and construction of the system; the functional or operational principles; and the
performance characteristics, including emission reduction, fuel consumption, relia-
bility, maintainability, driveability, safety, installation and maintenance require-
ments, and costs. These characteristics were then summarized, with consideration of
the system's development status, to highlight the overall feasibility of each system
for retrofit use. Some of the basic ground rules used in evaluating these character-
istics were as follows:
a. Emission Reduction: Practically all devices were analyzed for emission re-
duction performance in terms of exhaust emissions. Only two devices had
data other than for exhaust emissions and these were for particulate matter.
No fuel evaporative or blowby emissions data were reported by the develop-
ment sources.
1-4
-------
In using the exhaust emissions data reported by the development sources,
preference was given to data measured by means of the 1972 Federal Test Pro-
cedure constant-volume-sampling (CVS) mass measurement, grams-per-mile
method. Exhaust emissions data obtained by the concentration measurement,
parts-per-million method of the 1970 Federal Test Procedure were given se-
condary preference. In all cases the number of tests, as well as the test
procedure, were considered important.
Emission reduction performance was quantified as percentage reduction. To
calculate this, it was necessary for a device to have data for the exhaust
emissions of the test vehicle without the device installed (referred to as
the baseline) and then a second set of data for the same vehicle with the
device installed.
b. Fuel Consumption: Fuel consumption data were obtained in the representative
device tests performed under the 1972 Federal Test Procedure as part of the
retrofit study. Preference was given to these data; however, in the absence
of such data, developer fuel consumption test results were reported - though
not used in the performance analysis of Volume III. In all cases, fuel con-
sumption data were reviewed with due consideration for the number of tests
represented, because of the adverse impact fuel consumption can have on the
cost feasibility of a device.
c. Reliability: Reliability was considered in terms of the overall service
life of a device in mean-miles-before-total-failure (MM3TF) and in mean-
miles-before-partial-failure (MMBPF). Total failure was defined as a
failure which would make a device completely ineffective in accomplishing
its emission control purpose, and would require replacement of all or a large
number of the principal components of a device. Partial failure was defined
as the failure of a device component that could affect performance adversely,
but not constitute total device failure. Because of the general lack of
data on the reliability of automotive components and the short study sched-
ule, no attempt was made in most cases to quantify partial failures. Com-
ponents which could fail were identified, but the mean miles before partial
failure were generally considered to be the same as the mean miles before
total failure. The mean-time-to-repair (MTTR) a failed device was calcu-
lated as the average of all repair times.
d. Maintainability: Maintainability was analyzed in terms of mean-miles-before
maintenance (MMBM) and mean-time-to-maintain (MTTM). MMBM was calculated as
the average mileage of all maintenance actions. MTTM was calculated as the
average of the maintenance hours for all maintenance periods.
e. Driveability: Driveability analysis was based on data obtained from the
retrofit program and development sources, though the latter were fcr the
most part not based on formal procedures and therefore were not considered
conclusive. Each device for which valid data were obtained was studied for
both critical and general driveability characteristics. Critical character-
istics included stall and backfire. General driveability included starting
1-5
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and idle and the hesitation, surge, and stretchiness characteristics
associated with cruise or acceleration.
f. Safety: Safety characteristics of a device were analyzed in terms of those
which could be hazardous to humans, either in or outside the vehicle, and
to the vehicle.
g. Installation; The installation requirements of a device were analyzed in
terms of the procedural steps required to accomplish installation and the
associated tools and skill levels. The amount of time required for each
step was estimated.
h. Costs; The costs associated with a device were analyzed both in terms of
the initial installation cost, including labor and material, and the re-
curring cost. Recurring cost was estimated on the basis of maintenance
and such operating costs as fuel consumption or savings. Recurring cost
was tabulated along with initial cost so as to provide an indication of
the overall cost which a device might entail.
In some cases, the system information provided by the retrofit source was too vague
to apply the detailed system description approach and reach a feasibility conclusion.
In each such case, the available information was summarized even though no conclusions
as to the system's suitability for emission reduction use on a retrofit basis could
be made. When the developer's explanation of operating principles for a device
could not be substantiated on the basis of current vehicle emission control tech-
nology, these claims were not subjected to test or analysis. Sometimes, the de-
veloper's explanation was quoted. These quotations should not be construed as an
expression of either agreement or disagreement with the developer's claims. It
should be noted that some material provided by the developers was sales literature
containing highly promotional claims for device performance and theory of operation.
It was not within the scope of this study to dispute such claims.
1.5 DATA SURVEY RESULTS
The data survey by which the study was initiated indicated 469 potential sources of
information about retrofit methods that are either under development or in produc-
tion for application to used cars. The information obtained through these contacts,
including the data development effort, provided an overview of the current state of
retrofit technology, in addition to providing the specific details of the feasibility
of individual retrofit devices. From this overview, it was possible to evaluate the
general character of development efforts in the retrofit field, in terms of the
soundness of the design concepts being used and the quality of the design engineer-
ing represented by the hardware mechanization of these concepts.
In general, retrofit devices were found to vary considerably in basic concepts, in the
analytical substantiation of the concepts and their conversion to hardware, in. the
extent of product engineering, in the rationale as to what constitutes emission
reduction, in test methods, in the quality of prototypes, and in general business or
financial backing and marketability. The devices found to exist ranged from devices
based on sound engineering principles and highly sophisticated mechanisms to devices
offering little or no potential emission reduction. In some cases, these latter de-
vices actually increased emissions over the level obtained with the uncontrolled
vehicle. In other cases the devices showed beneficial reduction of emissions, but
were still in a relatively undeveloped prototype stage.
1-6
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The developers and producers of the devices were found to range from individuals who
are investing their own time and money, to established engineering firms that are en-
gaged in the retrofit field on a full-time business basis. In general, the informa-
tion obtained from individual developers was characterized by the lack of a compre-
hensive developmental effort. Accordingly, the data obtained were frequently frag-
mentary from a total system engineering viewpoint. Most had some emission test data.
The lack of detailed system performance data—including driveability, reliability,
maintainability, and safety data—appears in the case of many individual developers,
and may be caused by a lack of indepth financing. Nonetheless, a number of these sys-
tems appear to have a sound technical approach for retrofit application.
The sources of comprehensive data were most frequently firms which are formally en-
gaged in emission control products or in the automotive component field. Many com-
panies were only in the initial stages of developing viable approaches to retrofit
requirements and some were already marketing devices for use in controlling emissions.
The main concern with some of these devices is whether they should be classed as emis-
sion control devices or, perhaps more appropriately, as means to enhance engine per-
formance. In other cases, the products being marketed are viable emission controls
awaiting legal enforcement of their use for wide scale retrofit application.
The detailed results of the data survey are presented in Volume V, Appredix V-l.
These results provided a basic profile of the state of retrofit method technology
from the retrofit developer. Detailed procedures of the data survey are presented in
Volume IV.
Of 456 sources contacted directly for information on retrofit methods, 291 did not
respond to the letter of inquiry. Of the 165 who did respond, 91 declined to parti-
cipate, even though 40 were developers of retrofit devices. Of the 87 indicating
interest in the program, only 33 returned the detailed data questionnaire sent them
after the initial letter of inquiry.
It is also significant that among the 87 showing interest, 80 reportedly had retrofit
devices in the form of hardware. However, of the 33 that returned data questionnaires,
26 had hardware to submit for evaluation.
These contacts were made on a worldwide basis. The data questionnaire packages
received are presented in Volume V. Among the systems evaluated in this study,
one was discontinued as a result of the developer requesting withdrawal from the
program (Device 38).
Table 1-2 summarizes the results of the data survey. These results indicate that
only 28 percent of the 92 developers who reportedly had hardware were aggressively
developing their devices and were prepared to demonstrate them. The predominant per-
centage of the 26 hardware devices provided were in the exhaust emission control
group. Although no evaporative emission control system was found for retrofit use
other than in combination with other emission control techniques, a new model vehicle
evaporative control system was evaluated for retrofit cost feasibility.
1-7
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Table 1-2. DATA SURVEY RESULTS
RETROFIT SOURCE ITEM
a.
b.
c.
d.
e.
f.
g-
h.
Total retrofit sources
Total sources contacted by Letter of Inquiry
Source data provided only by EPA
No response received to Letter of Inquiry
Declined to participate
Will participate
Have retrofit hardware
Total number of devices evaluated in retrofit
program study
DEVICES EVALUATED ITEM
a.
b.
c.
d.
Returned data questionnaire (refer to Vol. V,
Appendix V-3)
Provided hardware
Devices previously tested by EPA
Devices already accredited for retrofit use
QUANTITY
469
456
13
291
91
87
92
65
QUANTITY
33
26
30
7
PERCENT OF TOTAL
RETROFIT SOURCES
100
97
3
62
19
18
20
14
PERCENT OF THE
TOTAL DEVICES
EVALUATED
51
40
46
11
1-8
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2 - RETROFIT
METHOD TECHNOLOGY
-------
SECTION 2
RETROFIT EMISSION CONTROL TECHNOLOGY
To understand retrofit devices as a means of controlling the emission of pollutants
from used cars, it is necessary first to know the pollutants to be controlled, the
sources or causes of these pollutants, and the principle methods which can be used
to control them. Such knowledge also is prerequisite to establishing a classifi-
cation system by which to organize retrofit devices for study, and to evaluate the
effectiveness and costs of the various devices to decide which may be better for
a particular application.
2.1 POLLUTANTS ATTRIBUTABLE TO GASOLINE- AND GASEOUS-FUELED VEHICLES
The pollutants of concern in emissions from gasoline- and gaseous-fueled vehicles
are carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The effects
of these pollutants on human health and welfare have been documented by EPA in
References 108, 109, and 110. Carbon monoxide is an odorless, colorless gas that has
long been associated with vehicle exhaust emissions as poisonous. Exposure to CO
of 10 ppm for 4 hours can impair psychomotor functions in humans.
The hydrocarbons emitted by these vehicles cover a wide range of compounds of various
molecular structure. Certain of these hydrocarbons are major causes of atmosphere
pollution due to their high chemical reactivity in the formation of photochemical
smog. (1) Of the more than 100 individual exhaust hydrocarbons identified, it is
the more reactive unsaturated elements that account for most of the harmful emissions
(Reference III).
The oxides of nitrogen, emitted as part of vehicle exhaust, are pollutants because
they combine with the reactive hydrocarbons to produce photochemical smog. Of the
12 million tons of nitrogen oxides estimated to be emitted into the atmosphere each
year in the U.S., approximately 50 percent are from motor vehicles (Reference 112).
2.2 VEHICLE SOURCES OF HC, CO AND NOx
Approximately 60 percent of the total hydrocarbons from uncontrolled vehicles and all
of the CO and NOx are emitted from the exhaust. The remaining 40 percent of the
emitted HC is divided approximately equally between the crankcase blowby emissions
and the evaporative emissions from the fuel tank and carburetor (Reference 114).
(1) The photochemical reactivity of hydrocarbons is measured on a relative basis by
the rate at which nitrogen dioxide (N0~) is formed in the presence of sunlight
or infrared, using controlled amounts of hydrocarbon, nitric oxide, and nitro-
gen dioxide (Reference 111).
2-1
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The presence of HC in the exhaust gas is an indication of incomplete combustion.
Whereas incomplete combustion of HC has been attributed to several causes, the
majority of the HC has its origin in an air-fuel mixture that is too rich, too
lean, or too cool for complete oxidation to occur during the combustion or exhaust
process (Reference 79). Insufficient oxygen supply could occur due to a rich fuel
mixture or poor fuel mixing. A major HC source, related to a cool mixture, is the
unburned gas in the quench zone of the combustion chamber. The temperature differ-
ential within an engine cylinder between the flame front of the ignited air-fuel
mixture and the surrounding surfaces - such as the engine head, cylinder walls,
and piston face - can be substantially different. The temperature of the gas layer
near the surface areas of the combustion chamber is a major determinant as to
whether fuel oxidation is complete or partial (Reference 79).
Another major source of HC is the unburned fuel that deposits in the combustion
chamber crevices, such as in the piston ring grooves and valve seats. These
deposits are attributable in part to the poor mixing characteristics of gasoline,
which enters the combustion chamber in droplet form. These droplets accumulate in
regions where the combustion flame is prevented from propagating. It has been
estimated that in some cases up to 50 percent of the exhaust HC may be from the
piston-ring crevices (Reference 30).
Both NOx and CO are products of the combustion process, whereas hydrocarbons are
inherent as a major constituent of gasoline. CO, in general, is caused by the
absence of sufficient oxygen to cpnvert CO to C02, combined with insufficient
reaction time under extreme engine operating conditions. An increase in oxygen,
as with a lean air-fuel ratio, while decreasing CO, tends to enhance NOx formation,
unless the peak temperatures conducive to NOx formation are prevented. If condi-
tions are favorable, reactions of the HC and CO gases exhausted from the combustion
chamber will continue in the exhaust ports, manifold and even in the tailpipe. The
nature of reactions that may occur in the exhaust system is influenced by the
amounts of carbon monoxide and hydrocarbons emitted. The extent of these exhaust
reactions depends on the temperature distribution within the exhaust system (Refer-
ence 79) .
2.3 PRINCIPLES OF RETROFIT METHODS FOR CONTROLLING VEHICLE EMISSIONS
The 65 retrofit devices studied were classified by emission source and retrofit
type, in accordance with the classification structure shown in Table 2-1. Most of
the retrofit types are based on the fundamental principles by which vehicle emis-
sions may be controlled, and most of the accepted principles used in retrofit
devices have already been incorporated on new model vehicles either as integral
engine modifications or auxiliary equipment. Exceptions are the catalytic converter
and the air bleed to intake manifold.
The basic operating principles and characteristics of the principle types of retro-
fit devices within each generic group of devices are summarized in the following
sections.
2.3.1 Exhaust Emission Control Systems - Group 1
The air-fuel mixture ingested through the carburetor and intake manifold is first
reacted and burned in the combustion chamber and then is reacted further in the
exhaust system. These two major sequences of reaction define the two broad
approaches to controlling exhaust emissions: (1) by minimizing the amount of
2-2
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Table 2-1. CLASSIFICATION OF RETROFIT METHODS
GROUP
1
2
3
4
TYPE
1.1
1.2
1.3
1.4
2.1
2.2
3.1
3.2
SUBTYPE
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.3.1
1.3.2
1.4.1
1.4.2
1.4.3
TITLE
EXHAUST EMISSION CONTROL SYSTEMS
Exhaust Gas Control Systems
Catalytic Converter
Thermal Reactor
Exhaust Gas Afterburner
Exhaust Gas Filter
Exhaust Gas Backpressure
Induction Control Systems
Air Bleed to Intake Manifold
Exhaust Gas Recirculation
Intake Manifold Modification
Carburetor Modification
Turbocharger
Fuel Injection
Ignition Control Systems
Ignition Timing Modification
Ignition Spark Modification
Fuel Modification
Alternative Fuel Conversion
Fuel Additive
Fuel Conditioner
CRANKCASE EMISSION CONTROL SYSTEMS
Closed System
Open System
EVAPORATIVE EMISSION CONTROL SYSTEMS
Crankcase Storage
Canister Storage
EMISSION CONTROL COMBINATIONS
2-3
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pollutants resulting from the combustion process and (2) by minimizing the amount
of pollutants allowed to escape from the exhaust pipe. The first approach is that
used in the induction and ignition control retrofit systems, and in the fuel modi-
fication systems. The second approach is that used in the exhaust gas control
systems.
2.3.1.1 Exhaust Gas Control Systems - Type 1.1
Retrofit devices of this type have in common some means of acting upon the pollu-
tants in the exhaust system to decrease the amount emitted to the atmosphere. The
more sophisticated techniques, such as catalytic conversion, thermal reactor, and
afterburning, accomplish this by chemically reacting the exhaust gas to convert
CO, HC, and NOx to a nonpolluting form. Another exhaust gas control method is that
represented by exhaust gas filtering, which physically removes particulate matter
from the exhaust, but may not affect other emissions.
Catalytic Converter - This type of device is typically a high-temperature
metal chamber that contains a catalyst material that promotes the oxidation
of CO and HC to water and carbon dioxide. This type of system is called a
single-bed oxidation catalyst. Dual-bed and tricomponent catalytic devices
are also being developed for sequential and simultaneous (respectively) reac-
tion of CO, HC, and NOx. However, none of these devices were submitted for
retrofit evaluation or application.
The catalysts being used are both of the base and noble metal types. Exten-
sive research and development is being performed to perfect both the catalysts
and the container configuration. One of the catalytic converter types evaluated
incorporates a pellet catalyst in a cylindrical metal container. Another
approach is to use a monolithic coated substrate or honeycomb grid in a metal
container. Most of the catalyst compositions are considered proprietary.
Typical base metal catalysts are vanadium, chromium, manganese, iron, cobalt,
nickel, copper, and zinc. These are usually combined as oxide compounds.
Supports such as alumina and silica are used for structural strength (Re-
ference 2).
Some of the base metal catalysts contain precious metals in trace amounts.
These precious or noble catalysts are usually platinum or palladium, deposited
on alumina or silica supports.
The catalytic converters are installed in the exhaust pipe as close as possible
to the exhaust manifold. The reason for this is to prevent too much tempera-
ture loss in the exhaust gas before it enters the converter. Converter warmup
time is a major factor in emission control effectiveness. Until the catalyst
reaches its reaction temperature, the exhaust gas flows through the catalyst
bed without any of the pollutants being converted. Normal operating range
may be 1,200° F or higher. The operating temperature also is a critical
factor on catalyst durability. At the higher temperatures, some attrition of
catalysts is usually encountered. This is generally not serious unless the
catalyst also becomes contaminated, as from oil or particulate matter. When
contaminated by oil, the catalyst may burn up.
To prevent overtemperature conditions, a thermal sensing system is sometimes
incorporated. This system may consist of a thermal switch that diverts the
exhaust gas through a bypass pipe around the converter. Converter chambers
2-4
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typically incorporate melt-out plugs that vent the exhaust through the conver-
ter body in the event of excessive temperature. To operate efficiently, ox-
idation catalytic converters require some excess of oxygen which can be pro-
vided by proper carburetor mixture or by an air pump operated off the engine
auxiliary power system.
Since current catalysts are sensitive to leaded fuels, use of nonleaded fuel
is an operational requirement for durability. Current technological develop-
ments in converters indicate that it will be about 1975 before catalytic
systems are incorporated on new model vehicles (Reference 20). A satisfactory
retrofit converter could be used on all vehicles up to the point of production
use.
Thermal Reactor - This type of device is similar to a catalytic converter
in that it reacts with the exhaust gas to change CO and HC to carbon dioxide and
water. The oxidation process, however, is performed in a thermal environment
produced and sustained within a specially designed exhaust manifold that re-
places the conventional exhaust manifold.
There are two basic types of thermal reactors: rich and lean. The rich thermal
reactor operates with a rich air-fuel mixture and requires secondary air in-
jection. The lean thermal reactor operates with a lean mixture and does not
require secondary air. For both the rich and lean thermal reactors, the re-
action chamber is sized and configured for three primary objectives: to sus-
tain residence time of the exhaust gas as long as possible to promote mixing,
and to maintain the highest possible temperature.
When using the rich thermal reactor the carburetion must be more rich than
normal. This inhibits NOx formation due to the lack of oxygen in the engine
combustion chamber. For the lean thermal reactor, it is possible to operate
at stoichiometric or leaner air-fuel ratios and.use exhaust gas recirculation
or vacuum advance disconnect to control NOx. In either case, the reactor must
be installed next to engine exhaust ports and designed to heat up promptly on
cold starts. The high operating temperatures up to 1,800°F, and thermal capa-
city require high-temperature materials of great durability. Major develop-
mental problems have been encountered in designing reactor chambers that can
withstand the prolonged thermal environment, particulate impact, possible
flameups, and vibration.
The lean thermal reactor does not require secondary air injection, since it
is operated on the fuel-lean side of stoichiometric with excess air. The lean
mixture produces lower concentrations of CO and HC during combustion and,
therefore, produces a lower reactor temperature than the rich-mixture thermal
reactor.
Exhaust Gas Afterburner - This type of device operates on the same principles
as the rich thermal reactor. The main difference is that the afterburner is
installed downstream of the exhaust manifold, and does not depend on the hot
exhaust gas for reaction temperature. The afterburner typically incorporates
an ignition unit, such as a spark plug, to initiate combustion within the
chamber. The fuel-rich exhaust gas is combusted in the presence of secondary
air usually supplied by an air pump. The gases are circulated within the
afterburner to oxidize CO and HC. As with the rich thermal reactor, NOx
formation during combustion may be reduced by the rich fuel mixture.
2-5
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Exhaust Gas Filter - This type of device is designed to control the emission
forparticipate matter from the exhaust. Currently, there are no Federal re-
gulations for particulate matter from vehicles. Two devices incorporating
this type of control (Devices 164 and 469) received a limited evaluation in the
retrofit study. Thus far, no complete information has been available on the
total particulate emissions rate from vehicles under realistic driving condi-
tions (Reference 73). It is known that vehicle exhaust contains lead salts,
carbon, iron rust, and semisolid or liquid particles such as tars and oil
mists.
One approach to controlling exhaust gas particulates is to separate and re-
tain the particulates in the exhaust system. This requires cooling the ex-
haust gas so that all particulates are solidified. Fine particles must be
agglomerated for ease of separation. All particles then must be separated
from the exhaust stream. This can be accomplished by direct filtration or
by a cyclone separator.
Exhaust Gas Backpressure - The emission control principle of this type of de-
vice has not yet been established, based on known investigations. Exhaust
backpressure in itself has an adverse effect on volumetric efficiency of an
engine and on power (Reference 24).
2.3.1.2 Induction Control Systems - Type 1.2
Modification of the induction of the air-fuel mixture to the combustion cylin-
der is one method of controlling the formation of pollutants during combustion.
The other two methods are the ignition control and fuel conversion systems.
Air Bleed to Intake Manifold - As shown in Figure 2-1, CO, HC, and NOx
concentrations in the exhaust of uncontrolled vehicles are directly
influenced by the air-fuel ratio at which the engine is operated. At
the stoichiometric air-fuel ratio (about 14.7:1), NOx is quite high,
while CO and HC are relatively low. At air-fuel ratios between 17
and 19, concentration emission levels of all three pollutants are
considerably lower than at stoichiometric. Current engine designs
are limited to air-fuel ratios below 19:1 to avoid excessive power
loss and rough engine operation due to lean misfire (Reference 2).
The air-bleed device as a retrofit approach is commonly implemented
by means of a tube with an orifice (fixed or variable area) con-
nected to the intake manifold. The device allows a metered amount
of air to lean the carburetor mixture. Some air-bleed devices
lean the air-fuel mixture at all engine speeds and load condi-
tions. Other air-bleed devices operate at certain prescribed en-
gine operating conditions, such as idle and deceleration.
Exhaust Gas Recirculation - As discussed in paragraph 2.2, the amount
of the nitrogen oxides formed during the combustion process depends
on the temperature of combustion. Higher temperatures yield more
nitrogen oxides. The peak flame temperature of combustion can be
lowered by introducing relatively inert substances into the air-
fuel mixture. The exhaust gases from an engine provide a conveni-
ent source of such substances. Exhaust gases are essentially inert
2-6
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I I I I I
i STOICHIOMETRIC
10 12 14 1* 18
AIR-FUEL RATIO
I I
MAXIMUM
As
o
5
i r
POWER
i ;i
FUEL i
CONSUMPTION!
I I I.I
i
i
<>l
10 11 12 13 14 15 16
AIR-FUEL RATIO
O
O
u
UJ
2
u
17
(a) EFFECTS ON AIR-FUEL RATIO ON
EXHAUST COMPOSITION
(b) EFFECT ON AIR-FUEL RATIO
ON POWER AND ECONOMY
Figure 2-1. EFFECTS OF AIR-FUEL RATIO (REFERENCE 114)
and also contain substantial quantities of water, which has a cooling effect.
The recirculation of part of the exhaust (usually from 10 to 15 per cent of
the engine airflow) thus limits the combustion temperature and reduces the
formation of nitrogen oxides.
In the retrofit devices evaluated, the amount of exhaust gas recirculated.is
controlled by an orifice or valve in the line leading from the exhaust to
the intake manifold.
Many different EGR system designs have been employed by the various develop-
ers. The location of the recirculated exhaust gas pickup, the point of in-
troduction of the recycled gas into the engine induction system, the meter-
ing devices, and their signal sources all can be varied greatly. In one
system, the recycled gas was taken from the heat riser area of the exhaust
manifold and metered directly to the intake manifold below the carburetor
throttle plate. In another, the recycle gas was picked up downstream of the
exhaust manifold, cooled, and introduced through a spacer plate above the
carburetor throttle plate. For driveability and engine performance reasons,
EGR is usually terminated at engine idle or wide-open-throttle conditions.
2-7
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Intake Manifold Modification - Intake manifold modification types are based on
the principle of reducing emissions by providing a more uniform air-fuel mixture
to the combustion chambers and better atomization, vaporization, and diffusion
of the mixture.
The typical approach reflected in the retrofit devices of this type consists
in screen and deflection plate inserts between the carburetor throttle plate and
the intake manifold, or between the manifold and the intake ports to the intake
valves.
Carburetor Modification - Devices studied in this category reflect an alternative
approach to optimizing the air-fuel ratio and air-fuel mixing qualities. These
devices vary in complexity from relatively simple devices for improving air-fuel
mixing to complete carburetor replacements.
Fuel Injection - This approach is based on the principle of improved air-fuel
mixing to optimize combustion. Fuel injection would eliminate the conven-
tional carburetor.
2.3.1.3 Ignition Control Systems - Type 1.3
Ignition Timing Modification - These systems represent another approach used to
control exhaust emissions during the combustion process. The basic technique
used in these devices is to retard the ignition timing or spark by disconnecting
the distributor vacuum advance unit. This has the effect of lowering peak com-
bustion temperature and, therefore, NOx formation is reduced. Retarding the spark
also moves the combustion event closer in time to the exhausting of the combus-
tion gases from the cylinder. Thus the exhaust gases are hotter and oxidation of
CO and HC may continue in the exhaust manifold. Devices in this category are pri-
marily NOx controls, and are sometimes used in combination with lean carburetion
and reactors to encompass CO and HC control.
To guard against engine overheating, these devices usually incorporate a thermal
switch in the cooling system that is interconnected with the vacuum line. When
the coolant temperature reaches the thermoswitch actuation temperature, the
vacuum is restored to advance the spark.
Ignition Spark Modification - This approach is based on prolonging the duration
of the ignition spark. These systems are generally designed to provide higher
secondary voltage for higher engine speeds and loads.
2.3.1.4 Fuel Modification - Type 1.4
Alternative Fuel Conversion - Retrofit methods evaluated in this -category consist
of the gaseous fuel conversions to compressed natural gas (CNG), liquified petro-
leum gas (LPG), or combination dual-fuel (gasoline and gaseous) systems.
LPG has been used as an automotive fuel for many years. Approximately 300,000 LPG
vehicles are estimated to be in operation nationally. There are currently more
than 2,000 natural-gas-fueled vehicles throughout the country. Thus far, these
are mainly experimental operations. While this represents a small part of the
automotive population, it indicates that the technical and economic problems asso-
ciated with the use of natural gas in competition with gasoline-fueled vehicles
have in some measure been resolved.
2-8
-------
Gaseous fuels, by their lower molecular weights and lesser amounts of carbon,
tend to produce fewer hydrocarbons that contribute to the formation of photo-
chemical smog.
The emissions of CO and HC are minimized by operation further on the lean side,
and this can be obtained without misfire with the use of gaseous fuels (Refer-
ence 30). One of the major problems associated with ignition and internal com-
bustion engines is that of lean misfire, which is a limiting factor in lean
carburetion of a conventional engine. Under certain conditions, misfire tends
to occur both on the rich or lean side of stoichiometric ratio, but particu-
larly on the lean. The gaseous fuels indicate a distinct advantage in regard
to antiknock performance.
Fuel Additive -- This approach has been associated over the years with engine
performance improvement, as well as a means of decreasing engine maintenance
requirements,. Fuel additives are designed to remove or inhibit deposit levels
in the carburetor and combustion chamber.
2.3.2 Crankcase Emission Control Systems - Group 2
Crankcase emissions from an uncontrolled vehicle may account for as much as 20 per-
cent of the total HC emission. If these emissions are controlled, the hydrocarbons
are cicirculated to the intake manifold. The crankcase emission control system pro-
vides a means of circulating air through the crankcase, mixing it with the blowby
gases, which are recirculated through a metering positive crankcase ventilation
(PCV) valve to the intake manifold for distribution on to the combustion chambers.
Ventilation air is drawn either directly from the engine compartment (open system),
or through the engine air cleaner through a hose (closed system), into the valve
cover. The metering valve is typically a variable orifice valve controlled by
intake manifold vacuum. A spring-loaded metering pin balances itself within the
val"ve in response to the changing manifold vacuum. As the vacuum changes, the
orifice area varies, and thereby controls the flow rate through the valve.
At idle conditions, the metering pin is at the minimum flow position and allows
about 1 to 3 cubic feet per minute (cfm) flow capacity (flow capacity depends on
engine application). As the engine load increases (12 inches of mercury intake mani-
fold vacuum or less), the metering pin repositions itself in response to the combi-
nation of the spring force and vacuum force, and in turn allows increased flow capa-
city. A maximum flow of 3 to 6 cfm occurs at approximately 6 inches mercury mani-
fold vacuum and then decreases as the vacuum becomes less,, approaching wide-open
throttle. If backfire occurs, the valve will completely close off the flow and pre-
vent possible crankcase explosions.
After a period of operation, the PCV valve may become clogged with deposits, re-
ducing and perhaps finally stopping all crankcase ventilation. Manufacturers of
crankcase control systems recommend cleaning or replacing the metering valve
periodically.
Because crankcase control systems are limited to blowby HC control, they are fre-
quently used in combination with control devices for exhaust CO, HC, and NOx.
These are generally compatible combinations. Care would have to be used in com-
bining blowby control with an air-bleed-to-intake manifold device, because of
the possibility of overleaning the carburetor mixture which could result in lean
2-9
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misfire under certain operating conditions.
2.3.3 Evaporative Emission Control Systems - Group 3
Evaporative emission control systems were not submitted for evaluation in the retro-
fit program. However, the feasibility of retrofitting a production system was
evaluated. Gasoline tanks and carburetors are vented to the atmosphere on pre-1970
California vehicles and on pre-1971 vehicles nationally.
Evaporative losses at the carburetor occur almost entirely after shutting off a hot
engine. The residual heat causes the fuel bowl temperature to rise to 150 - 200°F,
causing substantial boiling and vaporization of the fuel. Fuel tank evaporative
losses also occur while the car is parked, but could occur while running under
severe conditions. Evaporative losses vary because of many factors and may be as
much as 29 grams of fuel per soak period on a car without evaporative controls
(Reference 122).
The vapor-recovery approach in the evaporative emission control system on new
vehicles is based on using the crankcase as a storage area for vapors from the fuel
tank and carburetor. During the hot soak period after engine shutdown, the declin-
ing temperature in the crankcase causes a reduction in crankcase pressure sufficient
to induct vapors. During this period, evaporated vapors from the carburetor are
drawn into the crankcase. Vapor formed in the fuel tank is carried to a liquid-
vapor separator. The condensate returns to the fuel tank, and remaining vapors
are drawn into the crankcase. When the engine is started, the crankcase is purged
of vapors by the action of the positive crankcase ventilation system.
A sealed fuel tank with a fill-limiting device is required to ensure that enough
air is present in the tank at all times to allow for thermal expansion of the fuel.
A pressure vacuum relief gas tank cap is used to prevent excessive fuel tank pres-
sure or vacuum.
In the absorption-regeneration evaporative control system, a canister of activated
carbon traps the vapors and holds them until such time as they can be drawn back
into the induction system for burning in the combustion chamber. During a hot soak
period, vapor from the fuel tank is routed to a condenser and separator, and liquid
fuel is returned to the tank. The remaining vapor, along with the fuel vapor from
the carburetor, is routed to the canister filled with activated carbon which absorbs
the fuel vapor. When the engine is started, fresh purge air drawn through the
canister removes the trapped fuel vapor from the activated carbon and carries it
to the combustion chambers. A sealed fuel tank with air trapping space that cannot
be filled with fuel is required for thermal expansion. A vacuum and pressure-
relief gas tank cap is also used with this system.
2-10
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3 - EXHAUST
CONTROL SYSTEMS
-------
SECTION 3
GROUP 1 RETROFIT METHOD DESCRIPTIONS:
TYPE 1.1 - EXHAUST GAS CONTROL SYSTEMS
As noted in Section 2, the emission of HC, CO, and NOx pollutants from the exhaust of
gasoline-powered, light duty vehicles may be controlled basically in two ways: (1)
by inhibiting formation of the pollutants during the combustion event; and (2) once
they have formed, by changing their chemical composition to a nonpollutant form. The
latter is the approach to vehicle emission control represented by retrofit devices
classified as Type 1.1, Exhaust Gas Control Systems.
Most of the retrofit emission control devices in this category are characterized by a
common mode of operation in which the exhaust gas pollutants formed during the com-
bustion event are converted to a nonpolluting chemical form. These are typically de-
vices which oxidize the CO and HC pollutants to carbon dioxide and water by either
catalytic reaction, by thermal reaction, or by exhaust afterburning. Only one case
was found where a strictly physical approach to retrofit exhaust gas control was
being proposed; this was in the form of an exhaust gas filter. Filtering the
exhaust gas would be expected to have no direct effect on the chemical makeup of
the gas; however, it should remove particulate matter.
Another variation within the exhaust gas control group was that of a device which
applies backpressure in the exhaust system. Increased backpressure might have an
effect similar to exhaust gas recirculation in lowering combustion temperature and
thereby inhibiting NOx formation; however, this was not an apparent characteristic of
the backpressure device evaluated.
Of the 65 retrofit emission control devices for which data were obtained or developed,
12 were of the exhaust gas control type. Although devices of the exhaust gas recir-
culation type would appear to be part of the exhaust control group, they actually are
in the emission control class which inhibits the formation of NOx during combustion
and not in the class that treats the pollutant after formation. Devices of this type
are more appropriately classified as induction controls, and therefore are described
in Section 4.
The retrofit devices described in this section are listed in Table 3-1. As indicated
by this table, several of the retrofit devices incorporate more than one approach to
reducing emission of pollutants from the exhaust. These combination approaches are
intended to do one of two things: either to extend CO and HC control to include NOx
or to attain supplementary control of CO and HC in addition to some measure of NOx
control. One combination approach, such as that of Device 93, combines the basic
capability of a catalytic reactor for controlling CO and HC with the capability of
exhaust gas recirculation to control NOx. With the Device 96 combination, the ap-
proach is to enhance the basic capability for controlling CO and HC by adding spark
retard, which also inhibits NOx formation. Both of these may be considered system
approaches to emission control requirements, in that they have capability for con-
trolling all three pollutants. The system approach is typical of combination type
devices.
3-1
-------
Table 3-1. TYPE 1.1 - EXHAUST GAS CONTROL SYSTEM RETROFIT DEVICES
CATALYTIC CONVERTERS - SUBTYPE 1.1.1
DEVICE NO.
62(1)
93(1)
(1)
96(2)
292(1)
NOMENCLATURE
Catalytic Converter
Catalytic Converter with Exhaust Gas Recirculation, Spark Modifi-
cation, and Lean Idle Mixture
Catalytic Converter with Distributor Vacuum Advance Disconnect
Catalytic Converter
THERMAL REACTORS - SUBTYPE 1.1.2
31
244(1)
463(1)
468
Thermal Reaction by Turbine Blower Air Injection
Rich Thermal Reactor
Rich Thermal Reactor with Exhaust Gas Recirculation and Spark
Retard
Lean Thermal Reactor with Exhaust Gas Recirculation
EXHAUST GAS AFTERBURNER - SUBTYPE 1.1.3
308
425
Exhaust Gas Afterburner
Exhaust Gas Afterburner
EXHAUST GAS FILTER - SUBTYPE 1.1.4
164
Exhaust Gas Filter
EXHAUST GAS BACKPRESSURE - SUBTYPE 1.1.5
322(1)
Exhaust Gas Backpressure Valve
(1) Previously tested by EPA.
(2) Emission and driveability data developed in the retrofit study test
program .
(3) All data for devices having no footnote number adjacent to the device
number were obtained through the retrofit development or production source.
In the descriptions which follow, combination devices of the exhaust gas control group
are presented as part of the retrofit type most representative of the principal con-
trol concept. The major emission control combinations - those which integrate two or
more of the principal retrofit group control approaches - are described in Section 9.
3-2
-------
3.1 CATALYTIC CONVERTERS - RETROFIT SUBTYPE 1.1.1
As shown in Table 3-1, four retrofit devices incorporating catalytic oxidation of
CO and HC pollutants as a basic approach to exhaust control were found to be under
development. A data questionnaire response from the developer was received only
for Device 96. Information on Device 292 was obtained from sales literature
(Reference 12) distributed by the developer, and from a test report provided by EPA
(Reference 10). Information on Devices 62 and 93 was obtained from EPA test reports
(References 8 and 9).
3.1.1 Device 96: Catalytic Converter with Distributor Vacuum Advance Disconnect
Device 96 is a CO/HC-oxidation catalytic converter that, as an emission control
system, encompasses NOx control by means of a distributor vacuum advance disconnect
subsystem. This device is in limited production for test and evaluation, and was
selected as one of the four representative devices to be tested on the used-car
vehicle fleet of the retrofit program. Eleven test specimens of this device were
subjected to 17 emission and driveability tests. Two specimens were subsequently
subjected to a 25,000-mile durability test (refer to Volume IV for test procedures).
The developer of Device 96 is a manufacturer of catalytic materials. Although the
developer has experimented with dual- and tri-component catalytic converters for
control of NOx with CO and HC (as reported in Reference 2), the device configuration
tested in the retrofit program incorporated only CO and HC basic catalytic conver-
sion. Distributor vacuum advance disconnect was used to obtain supplementary HC
oxidation in the exhaust manifold upstream of the reactor, and to inhibit NOx for-
mation during combustion. In all, the developer identified four operational config-
urations of the device, incorporating components and operational provisions as
follows:
Vacuum Thermal
Catalytic Advance Air Protection
Conf igurat ion Converter Disconnect Pump System
A XX
B X
C X X X X
D X XX
Vacuum advance disconnect is used when NOx control is desired with CO and HC control.
An air pump is required when the carburetor cannot be tuned to a sufficiently high
air-fuel ratio to provide the air needed for the oxidation process. Configuration
A and C were the ones evaluated in the retrofit program. Both configurations were
the same, except for the deletion of the air pump from Configuration A.
3.1.1.1 Physical Description
Device 96 consists of a catalytic converter that is installed in the engine exhaust
system between the exhaust manifold and the muffler. The converter attaches di-
rectly to the exhaust manifold so as to process the exhaust gas at the highest pos-
sible temperature. Figure 3-1 shows the converter configuration tested in the
retrofit program.
3-3
-------
AD SUPPLY
INJECTION
PRESSURE MEAS OUTLETS: 1
TEMP AREAS OUTLET: 2
EXHAUST
INTAKE
CONVERTER CHAMBER
WITH CATALYST
FUER PLUG
BB549
Figure 3-1. DEVICE 96 CATALYTIC CONVERTER CONFIGURATION TESTED IN
RETROFIT PROGRAM - DEVELOPMENT MODEL
Figure 3-2a illustrates the installation of the converter on the 1965 Chevrolet,
6-cylinder, 194-cubic-inch-displacement (CID) vehicle used in the test program. An
8-cylinder engine would have a converter installed downstream from each exhaust mani-
fold.
The converter chamber is circular in cross-section and is made of welded stainless
steel. The chamber is 4.75 inches in diameter and 12 inches long for an 8-cylinder
engine. The chamber contains a pellet-type catalyst bed, with the pellets retained
by wire mesh screen. The catalyst bed consists of approximately 30 cubic inches of
pellets coated with a platinum material. The bed is filled through a removable
plug in the side of the chamber.
On older cars (pre-1968 and some 1968 cars) an air pump is usually required to
supply the amount of air needed to support the oxidation process in the converter. (1)
On later model cars, the carburetor can generally be tuned to a sufficiently high
air-fuel ratio to provide the amount of air needed. A typical air pump installation
is shown in Figure 3-2. The pump is mounted on the front of the engine where it can
be belt driven from the crankshaft pulley.
(1) According to the developer, use of a high capacity positive-crankcase-
ventilation (PCV) valve may be an alternative, less expensive way of obtaining
auxiliary air for the converter on older cars; the developer claimed a 50
percent emission decrease by use of an oversize PCV valve to provide air in
place of an air pump.
3-4
-------
THERMOSWITCH
VACUUM ADVANCE
DISCONNECT VALVE
(a) Installation of Device 96 - On 1965 Chevrolet
194-CID Test Vehicle
CATALYTIC
CONVERTER
(BELOW EXHAUST
MANIFOLD)
THERMOSWITCH
VACUUM
ADVANCE
DISCONNECT
VALVE
(b) Installation of Supplementary Air Pump for Device 96
on 1961 Chevrolet 283-CID Test Vehicle
Figure 3-2. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE
DISCONNECT INSTALLATION
3-5
-------
To protect the converter from overheating under unusually high flow of CO and HC
(which might occur if the carburetor or engine malfunctions), a melt-out plug is
incorporated in the chamber. When temperature in the chamber rises above the
the level at which the catalyst can operate without being damaged, the plug melts
and the exhaust gas is vented directly into the ambient air. When an air pump is
used to supply auxiliary air, a thermal protection system is required in addition
to the melt-out plug. This system consists of a thermocouple installed in the
converter, wired to an electronic control which is preset to a limit temperature
and which energizes a solenoid to divert the air pump output away from the con-
verter chamber when the limit temperature is exceeded.
To disconnect the standard distributor vacuum advance system, a thermoswitch,
installed in the radiator water return line, is used. The vacuum advance hose
is connected through the thermoswitch, which is normally closed, preventing the
intake vacuum from actuating the distributor vacuum advance mechanism.
3.1.1.2 Functional Description
The function of Device 96 is to decrease CO, HC, and NOx pollutants in exhaust emis-
sions. CO and HC react with oxygen in a catalytic platinum bed to produce carbon
dioxide and water. Formulation of NOx is inhibited during the combustion event by
use of retarded ignition timing.
A simplified block diagram of the overall catalytic converter and vacuum advance
disconnect system is shown in Figure 3-3.
The NOx reduction is achieved by disconnecting the distributor vacuum advance.
The thermoswitch installed in the distributor vacuum advance line keeps thetvacuum
advance disconnected during all engine operating modes, unless the engine coolant
temperature rises to the point where the thermoswitch opens, allowing the vacuum
advance to operate. In particular, at idle and mid-load ranges of engine operation,
the temperature of the coolant may rise beyqnd the acceptable limit, because of the
retarded ignition timing. The purpose of the thermoswitch is to sense engine over-
heating, through the coolant, and restore the vacuum advance to normal operation.
Normally, the thermoswitch disconnects the vacuum advance, and the cooler combus-
tion event inhibits the formation of NOx. Because exhaust temperature increases,
some HC is actually oxidized during exhaust. Since the carburetor is leaned out
to as high an air-fuel ratio as the engine will accept to provide the air required
for catalyst operation, the greater amount of air in the combustion chamber allows
for more complete oxidation of CO and HC even before the catalytic converter part
of the system is reached.
The higher exhaust gas temperature caused by high air-fuel ratio and ignition tim-
ing retard makes the converter more efficient. To oxidize CO and HC entering the
converter as part of the exhaust, catalyst temperature in the range of 1,000 to
1,600°F is required, along with enough air to support oxidation. The temperature of
exhaust gas entering the converter is from 900 to 1,400°F, with the ignition timing
retard provided by the vacuum advance disconnect subsystem of Device 96. The
air required to support oxidation comes from leaning out the carburetor to a high
3-6
-------
ENGINE
CARBURETOR AND INTAKE MANIFOLD
L4r
•NOX INHIBITED BY
VACUUM ADVANCE
DISCONNECT.
CONVERTER
CHAMBER WITH
CATALYST
EXHAUST MANIFOLD |
CO
AND
HT
STANDARD EXHAUST MUFFLER
Figure 3-3. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE
: DISCONNECT FUNCTIONAL DIAGRAM
air-fuel ratio, from the auxiliary air pump, if needed, or from both. As the
exhaust gas flows through the catalyst bed, CO and HC are oxidized to carbon dioxide
and water.
Since the temperature of the catalyst is in part determined by the amount of CO and
HC being oxidized, unusual amounts of CO and HC can cause excessive temperature
that may degrade, if not destroy, the catalyst. The thermocouple shown in Figure
3-3 monitors the temperature of the converter, so that, in the event of excess tem-
perature, the air from the pump can be diverted by the air bypass valve until the
temperature drops to an acceptable level. The air bypass valve has to be reset
manually to restore the air pump to normal operation.
The melt-out plug in the converter chamber is provided as a backup overheat protec-
tion whether or not an air pump is used. Should the plug melt because of abnormal
exhaust gas temperature, the exhaust is vented to the atmosphere through the open-
ing. This produces a noise similar to a muffler that has a hole in it.
3.1.1.3 Performance Characteristics
Emission test results obtained in 17 tests of Device 96 using the 1972 Federal Test
Procedure (Reference 3) are tabulated in Table 3-2.
3-7
-------
Table 3-2. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE
DISCONNECT EMISSION REDUCTION AND FUEL
CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Chev 194
Without Device
With Device
Percent Reduction
1965 Ford 289
Without Device
With Device
Percent Reduction
1965 Plymouth 318
Without Device
With Device
Percent Reduction
1965 Chev 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reduction
1961 CheV 283
Without Device
With Device
Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS/MILE
HC
* *
11.09 8.12
1.65 3.93
85.1 51.6
* *
8.85 10.36
0.69 2.53
92.2 75.6
*
6.62 7.06
4.36 2.41
34.1 65.9
* *
8.80 7.98
1.17 1.99
86.7 75.1
6.73 8.37
4.00 5.16
40.6 38.4
*
7 .47 5765"
2.38 2.90
68.1 48.7
POOLED MEAN PERCENT REDUCTION
(4)
CO
* *
85.06 75.39
18.42 17.01
78.3 77.4
* *
121.83 149.77
5.95 55.09
95.1 63.2
*
101.94 68.90
89.61 33.59
12.1 51.2
* *
69.76 53.65
0.57 12.53
99.2 76.6
74.88 104.45
56.80 76.38
24.1 26.9
*
"77:44 72.81
51.99 69.86
32.9 4.1
NOx
* *
2.87 1.72
0.67 1.45
76.7 15.7
* *
2.83 1.29
0.99 0.76
.65.0 41.1
*
3.33 3.24
1.04 2.26
68.8 30.2
* *
2.87 -2.49
1.78 1.08
38.0 56.6
1.90 2.56
0.64 1.84
66.3 28.1
*
1.82 1.72
1.19 1.52
34.6 11.6
FUEL
MILES/
GALLON
*
12.3
15.7
28.0
*
11.6
13.7
-18.1
14.2
13.2
7.0
*
14.2
11.7
18.0
12.1
11.7
3.3
*
13.5
11.2
17.0
RC 68.4 CO 62.6
*
15.7
13.2
16.0
*
12.3
11.0
11.0
*
11.7
11.4
3.0
*
' 14.5
13.7
6.0
11.4
10.4
9.0
13.5
' 10.7
20.1
TAYLOR TEST RESULTS
POLLUTANT GRAMS/
MTT.E
HC
(2)
3.59
1.20
66.6
3.46
0.51
85.3
4.63
1.35
70.8
*
4.08
0.29
92.9
*
3.55
0.49
86.2
CO
(2)
59.16
19.29
67.4
46.50
7.83
83.2
43.65
9.78
77.6
*
64.45
0.30
99.5
*
36.34
1.51
95.8
NOx
(2)
2.61
1.26
51.7
4.34
1.82
58.1
5.14
1.97
61.7
*
2.83
1.20
57.6
*
3.28
1.64
50.0
FUEL
MILES/
GALLON
(2)
(3)
13.5
(3)
13.0
14.2
-9.2
10.0
13.2
-32.0
*
14.0
15.4
-10.0
*
14.5
14.0
-3.4
NOx 47.8 FUEL 1.0
(1) Emission results obtained by Olson Laboratories In tests performed under Contract 68-04-0038
using 1972 Federal Test Procedure (Reference 3). Fuel consumption was measured during these tests.
(2) No teat.
(3) Test data Invalid.
(4) Anaheim and Taylor results combined.
* With air pump.
As noted in Table 3-2, seven of the tests were performed with the device in Config-
uration A (without auxiliary air pump). The average emission reductions of CO, HC,
and NOx with and without air pumps are summarized in Table 3-3.
Table 3-3. DEVICE 96 AVERAGE EMISSION REDUCTION PERFORMANCE
SYSTEM CONFIGURATION
A (without air pump)
C (with air pump)
PERCENT REDUCTION
HC
54.9
77.9
CO
42.2
76.9
NOx
49.5
46.6
PERCENT CHANGE
FUEL MILES/GALLON
0.3
-1.8
3-8
-------
The reductions shown for Configuration A are particularly significant in that
they were obtained in the lower cost configuration, in which the air pump, which
is relatively expensive (refer to paragraph 3.1.1.8), is not required.
The developer claims that tests have .shown emission reductions of 50 percent with
auxiliary air provided by a,n oversized PCV valve rather than an air pump. The
developer states that this was accomplished "by replacing the PCV valve with one
of larger capacity to lean put the mixture at cruise conditions and then ad-
justing the idle mixture adjustment screws to lean best idle" (Reference 4).
The results shown in Table 3r2 are further corroborated by cold-start emission
tests to the 1972 constant-volume-sampling (CVS) Federal Test Procedure (Reference
3) reported by the developer. The results of these developer-rreported tests are
summarized in Table 3-4.
Table 3-4. DEVICE 96 EMISSION REDUCTION PERFORMANCE REPORTED BY
DEVELOPER (REFERENCE 4) (1)
VEHICLE CONFIGURATION
Without Device
With Device and Air Pump
Percent Reduction
With Device and No Air Pump
Percent Reduction
POLLUTANT GRAMS /MILE
HC
7.48
0.65
91
5t85
21.8
CO
95.5
1.3
98
37.7
60.5
NOx
Not Reported
Not Reported
< Not Reported
(1) Results obtained with 1965 Chevrolet, with 327^cubic^inch^displacement
engine, using cpldistart 1972 Federal Test Procedure, as reported in
Reference 4. One/ test: under each condition.
The developer of Device 96 has also been active in the development of a tri-
component catalytic converter (Referenced). The tricomponent system has a three-
way catalyst bed for simultaneous reduction of CO, HC, and NOx; thus disconnecting
the distributor vacuum advance would not be required as a means of NOx control.
EPA has performed emission tests on this system as reported in Reference 5, with
results shown in Table 3*5.
The developer has determined in further investigations into the NOx reduction
characteristics of this device that NOx reduction is optimum with the air-fuel
mixture slightly on t;he rich side of the stoichiometric ratio.
3-9
-------
Table 3-5. EMISSION TEST RESULTS OBTAINED BY EPA ON TRICOMPONENT CATA-
LYTIC CONVERTER PROVIDED BY DEVICE^96 DEVELOPER (REFERENCE 5) (1)
TEST
1
2
POLLUTANT GRAMS /MILE
HC
2.3
1.4
CO
32
10
NOx
(2)
0.6
0.8
(3)
1.3
1.1
(1) Results obtained with 1970 Volkswagen, with 98-cubic-inch-displacement
engine and automatic transmission using 1972 Federal Test Procedure. Stock
fuel injection was modified to prevent fuel cutoff during deceleration and
the catalytic converter was installed in place of the standard muffler
(Reference 5) .
(2) As measured by wet chemical modified Saltzman technique.
(3) As measured by electrochemical detection system.
3.1.1.4 Reliability
The principal components influencing the reliability of Device 96 are as follows:
Catalyst
Converter chamber
Air pump and drive belt
Thermoswitch and vacuum hoses
a.
b.
c.
d.
e. Air bypass solenoid valve and thermocouple.
The components listed above are comparable to existing automotive components which
have life expectancies well in excess of .50,000 mean-miles-before-total-failure
(MMBTF) - the useful life of light duty vehicle emission controls as specified in
the Clean Air Amendments of 1970 (Reference 6) and the standard specified by Cali-
fornia for retrofit device accreditation (Reference 7). Item b, the converter
chamber, has been tested by the developer for 50,000 miles with no failure.
The catalyst is the critical component. Although prototype catalysts have been
tested by the developer to 22,000 miles before significant attrition due to thermal ex-
posure occurred, the catalyst used in Device 96 has not been tested for exhaust emis-
sions beyond 10,000 miles. A minor decrease in the conversion efficiency of the
catalyst occurred up to 4,000 miles, but no further loss in efficiency occurred
to the 10,000-mile test limit. In Reference 4, the developer reports that the
catalyst used in Device 96 was subjected to 50 thermal cycles to 1,825°F without
any weight loss, and to 54 cycles to 1,900°F with 2.9 percent weight loss.
These tests were performed with the converter on a Cooperative Fuel Research
(CFR) engine. One CFR thermal test cycle consists of 15 minutes at peak
temperature with full auxiliary air, 10 minutes with auxiliary air off, and
5 minutes with fuel off but with auxiliary air on to cool the catalyst bed.
Fifty cycles is equivalent to 12.5 hours of operation at peak temperature.
3-10
-------
The catalyst can be adversely affected by lead additives in the gasoline and by oil
blowby, as well as by operation at excessive temperature. The effect of excessive
temperature is attrition of the catalyst and the consequent loss of effective catalyst
surface area for reacting with the incoming exhaust gas. The effect of lead additives
is loss of catalyst activity either by chemical or physical interactions, or both,
between the lead and the catalyst (Reference 2).
The developer of Device 96 has verified through tests that the emission reduction
effectiveness of the device is greatly impaired when the fuel contains laad addi-
tives. The extent to which the catalyst tolerates occasional lead contamination,
from fueling errors or from lead deposits that have accumulated in the engines and
fuel lines of used cars, was investigated in the durability test program (1). Oil
blowby due to worn piston rings can similarly affect the catalyst adversely, as
indicated by the results of durability testing.
The resistance of the Device 96 catalyst to thermal attrition indicates that the
device will have satisfactory reliability if maintained correctly and if unleaded
fuel is used. Overall reliability of the device, however, is influenced by the
condition of the vehicle's engine. If the engine is excessively worn so that oil
consumption occurs, the catalyst can become ineffective, just as it would if used
with leaded gasoline.
3.1.1.5 Maintainability
According to the developer, the only scheduled maintenance required on the device
would be replacement of the catalyst at 25,000-mile intervals. A.vacuum cleaner
can be used to remove the old catalyst through the filler plug. Fresh catalyst
can be poured into the canister through the same plug. The canister should be
tapped as the new catalyst is added, so that the material settles evenly. This
procedure has been performed routinely by the developer on development units of the
device. As reported by the developer, the cost of a catalyst refill would be $15
and $20 for 6- and 8-cylinder engines, respectively.
Since an air pump is used and these normally incorporate an air filter, cleaning
of the filter would be required at least once every 12,000 miles.
The only unscheduled maintenance would be the replacement of the melt-out plug
should an engine malfunction cause excessive temperature in the catalyst chamber.
Replacement is by simple insertion of a new plug.
To obtain maximum effectiveness from this catalytic converter, the vehicle engine
must be maintained to preclude excessive blowby of engine oil into the exhaust
system. This means that the engine oil and filter have to be changed in accordance
with the regular schedule specified by the vehicle manufacturer to obtain maximum
piston ring life; and that excessively worn rings have to be replaced.
(1) The results of a 25,000-mile durability test that have been performed as part of
the retrofit study program will be reported in Volume VI of this report. Every
2,500 miles, a full tank of leaded fuel (Premium) was used instead of the un-
leaded fuel (No-Lead) normally used to determine the effects of accidental use
of leaded fuel in operational use and whether the catalyst recovers when use
of unleaded fuel is resumed.
3-11
-------
3.1.1.6 Driveability and Safety
No driveability or safety problems occurred in the 17 tests of Device 96 performed
as part of the retrofit study.
3.1.1.6.1 Driveability Characteristics. Table 3-6 shows the driveability results
obtained. The cold starting problems noted for Anaheim, California, Cars 1, 2, and
4 were attributed to the use of Indolene Clear Fuel. In subsequent driveability
tests, commercial unleaded fuel was used and the starting problems did not occur.
The principal driveability effect of the device is some decrease in fuel economy.
Fuel measurements during the emission tests of Table 3-2 indicate that fuel consump-
tion is approximately 1 percent greater with the device installed.
The developer specified unleaded fuel without phosphorous additives for acceptable
catalyst performance. The developer reported that in 190,000 miles of driving accu-
mulated on 62 vehicles with the device installed that fuel consumption increased by
as much as 2 percent. The developer attributes this increase to the use of distrib-
utor vacuum advance disconnect, which is the NOx control phase of the overall system.
The developer reported that driveability characteristics were satisfactory through-
out his tests.
3.1.1.6.2 Safety Characteristics. The design of the converter incorporates several
safety features. The exhaust gas inlet cone and the main body of the catalyst
chamber are insulated to protect the more sensitive areas of the engine compartment
from the heat of the catalytic reaction. The exhaust gas outlet has a larger sur-
face area than the inlet, so that more heat is dissipated downward, away from the
car, than into the engine compartment. The converter chamber wall temperatures are
generally not higher than exhaust manifold temperatures, for which adequate protec-
tion is usually found in most vehicle engine compartment areas.
A temperature sensitive melt plug is built into the outlet cone. This plug is
designed to fail at a temperature low enough to protect the catalyst and con-
verter body from the excessively high temperatures that might be generated in
the converter if the engine ignition system malfunction or prolonged periods
of high speed deceleration should feed fuel and air to the converter. Melting
of the plug vents exhaust gases directly to the atmosphere. Should this happen,
a noise level high enough to be heard by the vehicle operator is generated.
An overtemperature detection system is employed when an air pump is used. As
part of this system, a thermocouple is incorporated in the chamber to sense
catalyst bed temperature. During an over-temperature condition, the thermo-
couple signal actuates an air bypass solenoid valve that discharges the pump air
to the atmosphere. If the temperature continues to rise, the temperature sensi-
tive melt plug will provide an additional signal to the operator. As with the
melt plug, the noise of the air dumping through this valve is audible to the
vehicle operator. In most cases, the bypassing of the air will lower the temp-
erature sufficiently until the excess air and fuel condition has passed. The
bypass valve can be reset by a switch.
There has been no estimate of the amount of emissions that may be bypassed in
this manner. If the vacuum disconnect continues to work, NOx reduction would not
be affected; however, the thermoswitch in the engine coolant hose could reconnect
vacuum advance should the engine get hot enough, eliminating NOx control.
3-12
-------
Table 3-6. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE DISCONNECT
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
(1)
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
(1)
1965 CHEV.
194 CIO
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS (1)
CAR NO. 1
Decreased stall
during cold
start decelera-
tion
Increased start
time, rough Idle
& stall during
cold start Idle;
Increased stumble
during cold
start decelera-
tion
Increased
from 19.6
to 22.6
Increased
from 21.1
to 22.1)
CAR NO. 2
No effect
Decreased rough
Idle during hot
start Idle; in-
creased start
time during
cold start
Decreased
from 12.8
to 12.2
Constant
at
21.5
CAR NO. 3
No effect
Decreased
cranking
time during
cold start
Increased
from 12.3
to 12.7
Decreased
from 2h
to 19.5
CAR NO. 4
Increased stall
during cold
start decelera-
tion
Increased
number of
attempts to
start during
' cold start,
decreased stall
during cold
start idle
Increased
from 12.5
to 13.0
Increased
from 23.0
to 26.8
CAR NO. 5
No effect
Detonation
during hot
start acceler-
ation
Increased
from 8.9
to 9.8
Decreased
from 29. U
to 214.1
CAR NO. 6
No effect
Decreased
number of
attempts to
start during
cold start
Decreased
from 17-5
to 17.1*
Decreased
from 27-2
to 2U.3
Average decrease of 5.33 percent (reference Table 3-2)
TAYLOR, MICH., DRIVEABILITY TEST RESULTS
CAR NO. 8
No effect
No change in
driveability
Information
not available
Information
not available
CAR NO. 9
Increased stall
during cold
start acceler-
ation
Increased
amount of hes-
itation during
cold start and
stretchlness
acceleration '
Information
not available
Information
not available
CAR NO. 10
Improved
cold start
idle
Decreased hesi-
tation during
acceleration
Increased from
10.7 to. 12. 6
Decreased from
20.2 to 19.3
CAR NO. 11
No effect
Decreased
number of
attempts to
start dyrlng
cold start
Increased from
9.7 to 11.8
Decreased from
20.8 to 20.7
CAR NO. 12
No effect
Trace of hesi-
tation during
cold start
acceleration
Increased from
13.0 to 1U.3
Constant
at 2lt.l
Average Increase of 11.75 percent (reference Table 3-2)
(1) Pooled mean decrease In miles per gallon equals 1.0 percent.
3-13
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3.1.1.7 Installation Description
Prior to installing Device 96, the engine has to be tuned up to reduce exhaust
emissions of CO and HC to a minimum. This tuneup must include diagnosis and
repair of any engine components or systems affecting exhaust emissions. In
particular, the engine cylinders should be checked for compression adequacy,
to identify whether the piston rings should be replaced in order to preclude
excessive oil blowby into the exhaust and consequent impairment of the catalyst.
After the engine is tuned up and repaired as necessary, the thermoswitch is
installed in the cooling system to disconnect the distributor vacuum advance,
a converter chamber is installed at each exhaust manifold outlet and the air
pump (if required) with its air bypass valve and catalyst overtemperature
sensing system is installed.
A detailed description of the installation procedure is provided in Table 3-7, along
with tools and special equipment required. This procedure is a summary of detailed
installation instructions provided by the developer for a 1965 Chevrolet 327-CID
Type C Kit. Installation can be accomplished in a normally equipped repair shop
by the average mechanic. The average motorist would not have the necessary range
of equipment or skill.
3.1.1.8 Initial and Recurring Cost
Table 3-8 summarizes the estimated costs for Device 96. From the information avail-
able, it is estimated that the initial purchase and installation costs for this de-
vice ;will be $175, including an air pump, for 8-cylinder cars; and $143.75 for 6-
cylinder cars. If an air pump is not required, these costs would decrease approxi-
mately $85. The initial costs do not include the cost of the engine tuneup.
3.1.1o9 Feasibility Summary
When used in conjunction with initial engine tuneup and annual inspection,
the Device 96 catalytic converter should provide an effective reduction in HC
and CO emissions. Emission tests conducted during the retrofit study program,
using 1961 and 1965 vehicles indicate that the converter should be used with an
auxiliary air pump to obtain maximum emission reduction benefits. For the $85
initial cost difference for an air pump, some 25 percent improvement in emission
reduction effectiveness is gained. Tests conducted in the retrofit program indi-
cate an average improvement in HC emission reduction from approximately 55 to 78
percent and an average improvement in CO emission reductions from 42 to 77 percent
when an air pump injection system is used.
Reduction of NOx emissions with this system results primarily from disconnect
of the distributor vacuum advance and not from chemical reaction in the converter.
The vacuum advance disconnect used with this system is disconnected in all opera-
ting modes, which may contribute to some slightly adverse driveability as noted
in Table 3-6.
This device requires the use of unleaded fuel. Also, a major unknown factor is
this system's ability to withstand accidental contamination by exhaust particulates,
especially those encountered with leaded fuels. Information on this aspect of
device performance, obtained from durability tests, are documented in Volume VI.
3-14
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Table 3-7. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE DISCON-
NECT; INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Diagnose engine to insure proper opera-
tion. Repair or replace all defective
ignition and carburetor parts
2. Clean, flow test, or replace smog valve
as required
3. Set dwell time on ignition points
4. Adjust spark timing
5. Set carburetor mixture and speed at idle
6. Install thermo-vacuum switch in radiator
hose
7. Top off radiator coolant
8. Remove existing distributor vacuum
advance hose
9. Plug port on engine with rubber cap
10. Install new vacuum hose to manifold to
thermo-vacuum switch to distributor
11. Remove exhaust pipe from manifolds to
muffler
12. Position Part 4 (exhaust pipe) into the
muffler (do not clamp tight) (1)
13. Install Part 1 (left converter assembly)
14. Insert Part 3 (exhaust pipe extension)
into Part 4
15. Install Part 2 (right converter assembly)
into Part 3 and the right manifold flange
16. Align the system to prevent any interfer-
ences and tighten all bolts and clamps
17. Check the system for exhaust gas leaks
when the engine is running
TOOLS, EQUIPMENT
AND FACILITIES
Engine analyzer
Hand tools
Engine analyzer
Engine analyzer
Engine analyzer
a. Hand tools
b. Thermo-vacuum switch
Radiator coolant
Hand tools
Rubber cap
Vacuum hose
Hand tools
Exhaust pipe clamps
Left converter assembly
a. Exhaust pipe extension
b. Clamps
Right converter assembly
Hand tools
None
TIME
(MIN.)
15
15
5
5
5
10
2
2
2
3
10
5
5
5
5
15
5
(1) Part numbers refer to the developers detailed installation instructions
(see paragraph 3.1.1.7).
3-15
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Table 3-7. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE DISCONNECT:
INSTALLATION PROCEDURE (CONT)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MIN.)
18. Remove fan pulley
19. Remove thermostat housing
20. Install different thermostat housing,
spacer, and gaskets using cap screws
supplied
21. Install air pump mounting bracket and
bend fuel line to clear
22. Install elbow and gasket on air pump
23. Install air pump and tension adjusting
bracket
24. Install water pump pulley and air pump
belt
25. Install air pump pulley and adjust belt
tension
26. Connect radiator hose to thermostat
housing
27. Mount bypass valve on fire wall using
two sheet metal screws
28. Connect 3/4" heater hose between air pump
and bypass valve
29. Install antibackfire valves on air inlets
of exhaust
30. Connect equal lengths of 5/8" heater hose
between the bypass valve and antibackfire
valves
Hand tools
Hand tools
a. Hand tools
b. Thermostat housing
spacer
c. Gaskets
a. Hand tools
b. Mounting bracket
a. Hand tools
b. Elbow, gasket
a. Hand tools
b. Air pump
c. Tension adjusting
bracket
a. Hand tools
b. Air pump belt
a. Hand tools-
b. Air pump pulley
Hand tools"
a. Hand tools
b. Electric drill
c. Bypass valve
d. Sheet metal screws
a. 3/4" hose
b. Clamps
Antibackfire valves
a. 5/8" hose
b. Clamps
5
5
5
10
10
10
10
10
3-16
-------
Table 3-7. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE DISCONNECT:
INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
31. Check radiator hose and fuel line for
leaks
32. Select location for mounting secondary
air control. Minimum clearances: 6" on
back, 2" on sides, 1/2" on bottom
33. Drill holes and mount bracket with sheet
metal screws
34. Assemble housing to bracket
35. Provide 1/8" diameter opening through
firewall and run thermocouple through.
Secure with 1/8" compression fitting
36. Connect battery to terminals with 18-
gauge or larger wire
37. Connect thermocouple to socket provided
38. To test, move switch so that alarm cir-
cuit engages and latches. Test reset
by holding switch momentarily in reset
position.
TOOLS, EQUIPMENT
AND FACILITIES
None
None
a. Hand tools
b. Electric drill
c. Bracket
d. Sheet metal screw
a. Hand tools
b. Secondary air control
housing
a. Electric drill
b. Thermocouple
18-gauge electric wire
Hand tools
None
Total Time
TIME
(MIN.)
3
3
5
10
5
5
5
4.0
hrs
The developer has produced about 100 of these converters, but does not manufacture
or distribute any of the other system components. These components are obtainable
from existing manufacturers. For- standardization and quality control of mass pro-
duced systems, the developer should market the device as an integral system package
complete with all components and installation and inspection instructions.
In summary, this catalytic converter system appears to offer relatively exceptional
control of all three emissions when an air pump system is employed. The relatively
high initial installation cost detracts from its overall cost effectiveness for use
in a used car retrofit program, unless for some air pollution control requirements,
greatly reduced emissions are mandatory and cost is not a heavily weighted factor.
3-17
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Table 3-8. DEVICE 96 CATALYTIC CONVERTER WITH VACUUM ADVANCE DISCONNECT
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscel-
laneous
Labor
1. Instal-
lation
2. Test and
ad -just
DESCRIPTION
a. Exhaust line converters
b. Air pump
c. Catalyst bed overheat
protection system
d. Vacuum advance discon-
nect system
a. Hose
b. Clamps
c. Electric wire
d. Brackets
e. Sheet metal screws
f. Gaskets
g. Radiator coolant
As required by Table 3-7
As required by Table 3-7
LABOR HOURS OR
ITEM QUANTITY
a. Two for 8-cyl (1)
One for 6-cyl (1)
b. One
c. One
d. One
As required
3.5 hrs (8-cyl)
3.0 hrs (6-cyl)
0.5 hr
Total Initial Cost (2)
50,000-Mile
Recurring
Cost: (3)
Material
1. Replace-
ment
catalyst
2. Fuel
increase
Labor
1 . Air pump
filter
Includes replacement cost
Unleaded fuel (4)
Clean as required by
manufacturer
One refills (one every
25,000 miles)
Based on $0.03 per gallon
cost increase and 1% fuel
consumption increase over
12.5 miles per gallon
for 8-cyl and 16 mpg for
6-cyl
0.25 hr/12,000 miles
Total Recurring Cost
TOTAL COSTS
COST - DOLLARS
8-CYL
125.00
6-CYL
100.00
(Included in
above)
43.75
6.25
175.00
20.00
135.20
12.50
187.70
362.70
37.50
6.25
143.75
15.00
105.62
12.50
148.12
291.87
(1) Converter cost is estimated by the developer at $30 for a 6-cylinder engine
and $25 for an 8-cylinder engine. Chamber size is 5.75 by 4.4 inches for 6-
cylinder engines and 5.25 (length) by 5.375 (diameter) for 8-cylinder engines.
(2) Approximately $85 less if air pump is not required, based on labor and materi-
al for a complete air injection system installation.
(3) Recurring cost for 50,000-mile service life.
(4) $0.38 per gallon.
3-18
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3.1.2 Device 292; Catalytic Converter
The developer of Device 292 has been engaged since 1963 in the development and pro-
duction of platinum metal catalyst converters for exhaust emission control of liqui-
fied-petroleum-gas (LPG) powered material handling vehicles (Reference 12). Over
the past two years, with the move toward use of nonleaded fuels, tl;e developer has
renewed development efforts to adapt this converter to passenger cars.
Contacts with the developer indicated that he is more interested in new model
vehicle applications of Device 292 rather than retrofit to used cars (Reference 13).
Although a retrofit data survey questionnaire response was not provided by the
developer, data were obtained through sales brochures (Reference 12) and an EPA test
report (Reference 10) .
3.1.2.1 Physical Description
In the LPG-fuel material handling vehicle configuration shown in Figure 3-4, Device
292 consists of two major components: a catalytic converter and a section of
exhaust pipe containing an air filter and a venturi for mixing air with the exhaust
gas upstream of the converter chamber. The device is manufactured in sizes varying
from 3 inches in diameter and 9 inches long, to 6-3/8 inches in diameter and 12
inches long. A thermocouple, mounted in the converter chamber, is connected to a
temperature indicator meter located on the vehicle control panel. The venturi
pipe section is about 6 inches long and has a 3- by 3-inch air filter mounted on it.
Figure 3-4. TYPICAL DEVICE 292
CONFIGURATION FOR LPG-FUEL
MATERIAL HANDLING VEHICLE
(REFERENCE 12)
Figure 3-5. DEVICE 292 CCNFIGURATI01! FOR
GASOLINE ENGINE (REFERENCE 12)
Developmental versions of the device have been made in the configuration illustrated
in Figure 3-5 for use with the gasoline engines of passenger cars. These configura-
tions are approximately 6 inches in diameter by 20 inches in length. All versions
of the device incorporate platinum catalyst. The catalyst bed is typically a ceramic
honeycomb configuration.
3.1.2.2 Functional Description
Device 292 operates on the principle of oxidizing hydrocarbons and carbon monoxide
by means of a platinum catalyst. Production versions of the device are presently
3-19
-------
manufactured for use with LPG-fueled engines for operation of forklift vehicles in
enclosed spaces. Reference 12 states that the platinum catalyst used in the
device is wholly incompatible with leaded gasoline.
Figure 3-6 illustrates the LPG configuration functionally.
tion provided by Reference 12 is as follows:
The functional descrip-
"Raw exhaust, containing carbon monoxide and other combustibles,
enters exhaust tubing (1) furnished in each custom kit. The
gases go through the venturi (2), bringing in air through the
filter (3). Next, the exhaust gases, now mixed with air, are
burned in the catalyst chamber (4). The purifying oxidation
generates additional heat which is sensed by the thermocouple
(5) and pyrometer (6) circuit to monitor the reaction. At out-
let, the purified exhaust includes carbon dioxide and water vapor,
the final conversion products."
Figure 3-6. DEVICE 292 LPG CONFIGURATION CATALYTIC CONVERTER
FUNCTIONAL DIAGRAM (REFERENCE 12)
The light duty vehicle configuration apparently functions in much the same way, ex-
cept that an air pump may be required to inject auxiliary air rather than relying on
venturi vacuum to draw in air through a filter, as for the configuration shown
in Figure 3-6.
3.1.2.3 Performance Characteristics
Device 292 has been approved by the U.S. Coast Guard and the California Department
of Industrial Safety for use on LPG-fueled material handling machinery operating in
enclosed spaces. The device also has been certified by the State of California, Air
Resources Board, in Resolution 69-22, for use on LPG fueled forklift trucks inside
buildings.
3-20
-------
The catalyst currently used in the device reacts only with CO and HC exhaust
pollutants. The developer has indicated, however, that he is developing catalysts
capable of controlling NOx as well. Table 3-9 shows emission test results obtained
by the developer with the device installed on a forklift truck. The engine had
3,000 hours of operation at the time of device installation.
Table 3-9. DEVICE 292 LPG-FUEL EMISSION REDUCTION PERFORMANCE
REPORTED BY DEVELOPER (REFERENCE 12)
TEST CONDITION (1)
Idle
Governed Speed
POLLUTANT
HC (2)
PPM '
IN OUT
590 <50
110 <50
CH/A
(PPM)
IN OUT
320 <50
90 <50
C2H4
(PPM)
IN OUT
260 <50
250 <50
CO
(7,)
IN OUT
3.54 <0.006
1.34 <0.006
Smoke in exhaust: None at steady speed, slight on acceleration.
Odor in exhaust: None.
(1) Reference 12 provided no indication as to number of tests performed to
obtain measured emissions. The test vehicle was a 3,000-pound forklift with
162-CID engine.
(2) Calculated as n-hexane.
The developer reported in Reference 12 that the 1971 Ford Capri which won the 1970
Clean Air Race was equipped with his device as configured for light duty motor
vehicles.
Emission test results obtained by EPA with the device installed on a standard Army
M-151 1/4-ton truck and incorporating an auxiliary air pump are summarized in
Table 3-10.
Table 3-10. DEVICE 292 CATALYTIC CONVERTER EPA EMISSION TEST RESULTS WITH
AUXILIARY AIR PUMP (REFERENCE 10)
VEHICLE CONFIGURATION (3)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
CVS (1) FTP (2)
6.6 6.4
5.2 1.5
21.2 77.0
CO
CVS (1) FTP (2)
65.0 32.0
75.0 33.0
-15.4 -3.0
NOx
CVS (1) FTP (2)
3.9 2.0
2.3 1.6
41.0 20.0
(1) Results of one test using 1972 Federal Test Procedure constant volume sam-
pling (CVS) (Reference 3)
(2) Results of one test using 1970 Federal Test Procedure (FTP) (Reference 15)
(3) Test vehicle was a 1/4-ton M-151 Army standard truck with a 141-CID, 4-
cylinder engine. The vehicle weighed 3,000 pounds
3-21
-------
For these tests the vehicle muffler was replaced by the converter and auxiliary air
was provided to the converter by a shop air system with airflow maintained at 2 cubic
feet per minute.
3.1.2.4 Reliability
The developer stated that over 300 units of the device were in use on LPG-fueled
fork-lift trucks as of August 1968 (Reference 12). He further stated that "Many
installations on diesel-powered fork-lift trucks and mining machinery, monitored
weekly, have shown consistent oxidation of contaminants including carbon monoxide
during load cycles, even after 7,500 hours of operation. Table 3-11 shows the
percentage of CO and HC decrease at test intervals over 48,300 miles obtained by
the developer from a 1970 car, using the 1968 Federal Test Procedure (Reference 14).
Table 3-11. DEVICE 292 CATALYTIC CONVERTER EMISSION REDUCTION RELIABILITY
REPORTED BY DEVELOPER FOR 48,300 MILES OF OPERATION (REFERENCE 12) (1)
MILEAGE
570
4,852
11,106
16,393
24,657
33,500
36,641
48,300
HC (PPM)
WITHOUT
DEVICE
217
185
139
199
295
165
165
130
WITH
DEVICE
8
35
38
43
36
34
34
23
% DECREASE
96
81
73
78
87
79
79
82
CO (PPM)
WITHOUT
DEVICE
2084
2627
2250
1070
2080
3590
3590
1230
WITH
DEVICE
286
696
170
100
90
630
140
40
70 DECREASE
86
74
92
91
95
83
95
97
(1) Emission results obtained with 1970 Ford Torino (V-8) under 1968 Federal
Test Procedure with device installed on one exhaust manifold. The Auto-
mobile Manufacturers Association (AMA) driving schedule was used.
These results indicate relative stabilization of the catalyst after the 4,852-mile
emission test. Based on the data of Table 3-11, it appears that the reliability
(MMBTF) of the device would be in excess of 50,000 miles, provided:
a. Only unleaded gasoline is used
b. Any new additives which might be substituted for lead are
compatible with the platinum catalyst
c. Any auxiliary air is filtered to keep out particulate matter.
3.1.2.5 Maintainability
For the material handling vehicle version of Device 292, the developer used exhaust
venturi vacuum to intake ambient air into the converter through an air filter. For
retrofit applications to gasoline-fueled light duty vehicles, the developer would
use an auxiliary air pump (Reference 13). Since the catalyst indicates a reliability
3-22
-------
of 50,000 miles (1), the only routine maintenance anticipated is cleaning or
changing of the air intake filter. It is assumed that this maintenance would be
performed every 12,000 miles which requires 15 minutes.
Replacement of the catalyst would be required at 50,000 miles (1), if vehicle ser-
vice life extends beyond that point, or when indicated by a decrease in the reaction
temperature beyond an acceptable limit, which might also be caused by a dirty intake
air filter. It is assumed that a temperature sensing device would be incorporated
in the reactor chamber with an indicator on the vehicle dashboard. Catalyst replace-
ment time cannot be estimated because the installation requirements for an automotive
retrofit kit configuration of the device has not been defined by the developer.
3.1.2.6. Driveability and Safety
No driveability data were obtained from the developer other than that reflected in
Table 3-11. The developer indicated that more than 300 of the device configurations
for material handling vehicle have been retrofitted satisfactorily, and that Device
292 configurations for light duty, gasoline-fueled vehicles were used on 26 of 37
entries in the 1970 Clean Air Race (Reference 12). No information was obtained on
the temperature at which the converter functions. If it is significantly higher
than the temperatures of a conventional muffler or exhaust manifold, then additional
precautions might be required to preclude injury to personnel or damage to the
vehicle.
If catastrophic structural failure or fouling of the catalyst system occurred,
severely restricting exhaust gas flow, then a substantial or total loss of power
could result. This could be potentially hazardous if the vehicle is being driven.
It is assumed the converter chamber design would incorporate an exhaust relief
provision to preclude premature (less than 50,000 miles) chamber burn-through
which could result in venting of toxic fumes.
3.1.2.7 Installation Description
Device 292 installation consists in removing a straight section of the exhaust pipe
as close to the exhaust manifold as possible, and replacing this with the converter.
Information on air pump installation requirements was not obtainable. Table 3-12
delineates the installation procedure and identifies tools and special equipment
required. Installation can be accomplished in a normally equipped repair or muffler
shop by the average mechanic. Figure 3-7 shows a developmental installation of the
device.
3.1.2.8 Initial and Recurring Cost
Table 3-13 summarizes the costs for Device 292, based on the information available.
Use of an air pump and periodic replacement of catalyst could increase these costs
by approximately $100.
(1) This reliability is reported by the developer, but is not supported by
current data within vehicle exhaust catalyst technology.
3-23
-------
Table 3-12. DEVICE 292 CATALYTIC CONVERTER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove a straight section of exhaust
pipe about 18 inches long as close to
the exhaust manifold as possible.
2. Install the catalyst exhaust gas purifier
in the exhaust pipe to replace the sec-
tion removed.
TOOLS, EQUIPMENT
AND FACILITIES
a. Oxyacetylene torch
b. Car lift
a. Catalyst exhaust gas
purifier
b. Exhaust line clamps
Total Time
TIME
(MIN.)
30
30
1 hr
Figure 3-7. DEVICE 292 CATALYTIC CONVERTER LIGHT DUTY VEHICLE
DEVELOPMENTAL CONFIGURATION (REFERENCE 12)
3.1.2.9 Feasibility Summary
Device 292 is not presently available for retrofit application to light duty
motor vehicles. The developer has indicated that his interest is more in the
new model vehicle field, than in used car retrofit (Reference 12).
3-24
-------
Table 3-13. DEVICE 292 CATALYTIC CONVERTER INITIAL AND
RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor .
1. Installation
2. Test and adjust
50,000-Mile
Recurring Cost: (1)
Labor
1. Air filter
DESCRIPTION
Catalyst exhaust gas
purifier
Exhaust line clamps
Table 3-12
Clean in accordance
with manufacturer ' s
specifications
LABOR HOURS OR
ITEM QUANTITY
1 hr
Total Initial Cost
0.25 hr /12, 000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
$50 - $60
(Included in
above)
$12.50
$62.50-$72.50
$12.50
$12.50
$75 - $85 (2)
(1) Assuming no replacement catalyst or increased fuel consumption
(2) $160-$170 with air pump
Insufficient emission test data are available to reach conclusions as to Device
292's technical feasibility; however, the developer has successfully applied the
basic Device 292 concept to the exhaust control of material handling vehicles
equipped for LPG fuel, and developmental configurations of the automotive
version have been used on specially equipped cars, with satisfactory emission
reduction reported for CO and HC (Reference 12) .
In the test performed by EPA to the 1972 Federal Test Procedure, CO increased
(refer to Table 3-10). This is not characteristic of a catalytic converter,
and on this basis it could be considered infeasible. Further development effort
would be required to provide a Device 292 configuration suitable for retrofit
application to light duty motor vehicles and to achieve a consistent CO and HC
reduction effectiveness which would justify the cost of the device.
Because the developer's current interest emphasizes new model vehicles
applications, it appears at this time that retrofit availability of the device
will not be broadened beyond the existing retrofit configuration for material
handling vehicles.
3-25
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3.1.3 Device 62; Catalytic Converter
Device 62 is a catalytic converter for use in the control of CO and HC pollutants
in vehicle exhaust gas. Insufficient data were obtained for a complete evaluation
of this device. No response was received to the retrofit data survey question-
naire sent to the developer. The only data obtained were the results of emission
tests performed by EPA in March 1971. The technical and performance characteris-
tics summarized below are based on information in the EPA report on those tests
(Reference 8).
3.1.3.1 Physical Description
This device is described in the EPA report as an exhaust HC and CO catalytic
converter that replaces the standard vehicle muffler. The device requires
auxiliary air supply for effective operation of the catalyst. The converter has
an exhaust gas bypass system which routes exhaust gas around rather than through
the converter if it overheats. In the EPA test, air was supplied by a shop air
system. Air flow varied from 1.2 cubic feet per minute (cfm) at idle, to 1.8 cfm
at cruise, and 3.6 cfm during acceleration.
3.1.3.2 Functional Description
This device was apparently designed to oxidize HC and CO exhaust emissions in a
catalytic bed with auxiliary air supply. The operating principles of the device
should be similar to those for the catalytic converters described in paragraphs
3.1.1 and 3.1.2, for the catalytic phase during which CO and HC are oxidized to
carbon dioxide and water.
The exhaust bypass system was incorporated during the EPA test program to allow
the catalyst to cool if the catalyst temperature exceeded 1,150°F, a test limit.
3.1.3.3 Performance Characteristics
EPA has conducted several emission tests on this device. The results of the
1970 Federal Tests (Reference 15) are shown in Table 3-14 for each test cycle.
As shown by these results, the device indicates satisfactory reduction of HC
for each cycle of 7-mode test. CO reduction improved as the test progressed,
changing from an increase to a 50 percent reduction by the end of the test. HC
and CO results for cycle 7 both show reduction on the order of 50 percent. By
that time, the temperature of the catalyst had stabilized at 1,100°F.
The improvement in CO and HC oxidation capability of the converter as it reaches
its operating temperature (1,100°to 1,150°F) is shown in Figure 3-8. This figure
is based on the average percentage of emission reduction and the peak temperature
of the catalyst for each cycle of the 7-mode test performed by EPA (Table
3-14), from the time the catalyst reached 500°F. This figure indicates that as
the catalyst warmed up and reached its operating temperature, emissions of CO and
HC decreased by approximately 50 percent, whereas NOx increased. These are typical
emission reduction characteristics for a catalytic converter.
3-26
-------
z
o
§
O
M
W
3
W
75
50
25
— HC
GO
NO,
0
500
600 700 800 900 1000
CATALYST TEMPERATURE (F)
1100
Figure 3-8. DEVICE 62 CATALYTIC CONVERTER EMISSION REDUCTION PERFORMANCE
VERSUS CATALYST TEMPERATURE (REFERENCE 8)
Table 3-14. DEVICE 62 CATALYTIC CONVERTER EPA EMISSION TEST
RESULTS (REFERENCE 8) (1)
TEST
CYCLE
1
2
3
4
6
7
AVERAGE
PERCENT
REDUCTION
HC (PPM)
WITHOUT
DEVICE
2,000
327
394
298
319
305
607
WITH
DEVICE
919
339
254
221
182
143
343
44.0
CO (PERCENT)
WITHOUT
DEVICE
4.96
3.44
4.35
3.93
3.97
4.17
4.14
WITH
DEVICE
7.17
3.17
3.43
3.24
2.20
2.04
3.54
14.5
WOK (PPM)
WITHOUT
DEVICE
670
868
778
666
605
566
692
WITH
DEVICE
464
848
780
546
631
577
641
7.0
(1) Results obtained with a standard Army M-151 1/4-ton vehicle
(4-cylinder engine with 141-cubic-inch displacement), using
1970 Federal Test Procedure (Reference 15); one set of tests
with and without device installed.
3-27
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3.1.3.4 Reliability
EPA was unable to complete tests of Device 62 under the 1972 Federal Test Pro-
cedure because the catalyst repeatedly overheated when subjected to that test.
The Reference 8 EPA report states that:
"The catalyst showed reductions after it reached temperature
but achieving the temperature took a long time.
"The overtemperature problem appears to be the catalyst begin-
ning to burn at a temperature below the maximum rated temper-
ature of the catalyst. The most effective temperature for
reduction appears to be near the maximum temperature of the
catalyst."
Since overheating did not occur during the 7*-cycle test, it would appear that the
catalyst of Device 62 is sensitive to the more rigorous driving regime of the 1972
Federal Test Procedure. This sensitivity during the latter test, as noted in the
quotation above, may take the form of the catalyst actually burning before it
reaches operating temperature. Since burning causes attrition of the catalyst,
the catalyst may have low reliability for the overall range of driving operations
to which it would be subjected during the service life of a vehicle.
To prevent burning of the catalyst during the EPA test program, an exhaust bypass
line was incorporated. This bypass line circumvented the converter in the event
of catalyst overheating. A similar provision may be required in the production
design of Device 62. While such a provision would enhance the reliability of
the device, it would detract from its overall emission reduction capability,
since untreated exhaust would be vented to the atmosphere during catalyst over-
heat conditions.
3.1.3.5 Feasibility Summary
The lack of data on the component details of Device 62 precluded evaluation of its
maintainability requirements, driveability and safety characteristics, instal-
lation procedure, and costs. From the results of the EPA test program, the device
appears to be technically feasible for exhaust CO and HC control.
The tendency of the catalyst to burn, as when exposed to exhaust compositions
resulting from vehicle operation under the 1972 Federal Test Procedure, could
increase the cost of operating and maintaining the device unreasonably, if the
device is used without regard to operating limits. To keep such costs down, the
device might be restricted for use only under operating modes in which the condi-
tions causing the catalyst to burn would not occur. If the alternative of by-
passing the device when it overheats were used, then the overall emission control
effectiveness of the device would be less.
Based on these considerations, Device 62 would appear to be usable in applications
where some limitation as to operating modes is acceptable.
3-28
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3.1.4 Device 93; Catalytic Converter with Exhaust Gas Recirculation, Spark
Modification, arid Lean Idle Mixture
Device 93 illustrates the combination of a catalytic converter with exhaust gas
recirculation to achieve control of CO, HC, and NOx. Although the developer did
not respond to the retrofit data survey questionnaire, data on the emission reduc-
tion performance of the device were obtained from an EPA test report (Reference 9).
The following summary system evaluation is based on information obtained from that
document.
3.1.4.1 Physical Description
As described in Reference 9, Device 93 consists of a catalytic converter with
an auxiliary air pump, a special ignition system, and an engine modification for
exhaust gas recirculation.
carburetor for high air-fuel ratio.
3.1.4.2 Functional Description
In the catalytic converter phase of system operation, Device 93 would oxidize CO
and HC to carbon dioxide and water. Control of NOx is apparently accomplished by
an engine modification which alters valve timing. This timing change apparently
traps some of the exhaust gas in the cylinders as a residual carryover to the next
combustion cycle. The effect of this would be similar to recirculating the
exhaust gas from the exhaust system, as is the more customary way of implementing
exhaust gas recirculation.
The special ignition system is designed to provide more electrical energy for
spark propagation, so that the engine can be operated at high air-fuel ratios.
High air-fuel ratio tends to decrease CO and HC, but increases NOx.
3.1.4.3 Performance Characteristics
The results obtained by EPA in emission tests of Device 93 are summarized in
Table 3-15. Testing of the vehicle without the device installed was not possible,
because of the valve timing modification to the cam.
3-29
-------
Table 3-15. DEVICE 93 CATALYTIC CONVERTER WITH EXHAUST GAS RECIRCULATION,
SPARK MODIFICATION, AND LEAN IDLE MIXTURE EPA EMISSION TEST RESULTS
(REFERENCE 9) (1)
TEST
CONDITION
Average of 6 Tests Using
1972 Federal Test
Procedure (Reference 16)
One Test Using
1970 Federal Test
Procedure (Reference 15)
POLLUTANT (GM/MILE)
HC
COLD
0.9
0.3
HOT
0.1
0.1
CO
COLD
9.1
1.0
HOT
0.73
0.1
NOx
COLD
1.4
1.0
(2)
HOT
1.2
0.9
(2)
(1) Results obtained with a 1967 Pontiac Tempest station wagon
incorporating an overhead cam 6-cylinder engine.
(2) Combination test, consisting of nine repeats of the 1970
driving cycle using the 1972 mass sampling technique.
3.1.4.4 Feasibility Summary
Insufficient data as to the device's technical characteristics and performance
capability preclude evaluating it for reliability, maintainability, driveability
and safety, fuel consumption, installation requirements, and costs. The percentage
emission reduction for the hypothetical case shown above indicates that the device
would be effective for emission control of all three exhaust pollutants.
Although the emission reduction effectiveness of the device is significant, the
device may be too costly to implement as a retrofit method. Specific cost infor-
mation could not be developed because of the lack of information on the device;
however, by comparing the device with the other catalytic converters evaluated,
it would appear to be more costly in a retrofit application, because of the cam
timing modification and the auxiliary air pump. Thus, the cost of Device 93 might
be too unreasonably high to justify using it as a retrofit emission control device.
Because of its apparently high emission reduction effectiveness, however, the
device would be a candidate for further study to resolve its overall feasibility.
3-30
-------
3.2 THERMAL REACTOR - RETROFIT SUBTYPE 1.1.2
Thermal reactors like catalytic converters, control exhaust emissions of CO
and HC downstream of the combustion event by oxidation. The difference between
the two approaches is in the process by which oxidation is accomplished. Ther-
mal reactors accomplish oxidation by continued burning of the CO and HC compounds
within a high-temperature chamber attached directly to the engine at the ex-
haust ports in the place of the conventional exhaust manifold.
As discussed in Section 2, there are two basic types of thermal reactors: the
rich thermal reactor (RTR) and the lean thermal reactor (LTR). Among the four
thermal reactor systems studied, three may be categorized as rich thermal
reactors. There is only one device of the lean thermal reactor type known to
be under development (Reference 70). The existence of this device was discov-
ered too late in the study to obtain data from the developer; however, the tech-
nical characteristics of this device are summarized based on information in
Reference 2.
The four devices described in this paragraph are identified in Table 3-1. Device
244 is also used in a combination control system that is designed to control par-
ticulates, as well as CO, HC, and NOx. This utilization of Device 244 is discussed
in Section 9 (refer to Device 469).
In this report, thermal reactors are distinguished from catalytic reactors by re-
ferring to the latter as "converters." This is done for convenience in referring
to one or the other of the devices by a short-form expression. Both types of
devices are basically reactors for converting CO and HC to carbon dioxide and
water. Only the means for achieving this reaction are different.
3.2.1 Device 244; Rich Thermal Reactor
Device 244 has been under development for the past six years, and reflects ap-
plication of a systematic design, analysis, and test program (Reference 71).
The concept of extending combustion time outside the combustion chamber
by means of a thermal chamber is implemented in this device by a large-
volume, insulated reactor that replaces the conventional exhaust manifold. The
large volume appears to be a key design factor in the emission reduction
effectiveness of a thermal reactor, because the length of time the exhaust
gas can be contained in the reactor depends on volume: the longer the exposure
time, the more oxidation can take place.
The device is of the rich thermal reactor type. It operates at air-fuel ratios
•ranging generally from 11:1 to 11.5:1 (Reference 71). The relatively enriched
fuel mixture is required to achieve the gas temperatures that will support
oxidation, and to provide enough fuel byproducts of combustion to sustain
these temperatures by continued burning of the byproducts in the reactor chamber.
3-31
-------
These rich air-fuel mixtures, though primarily intended to enable the reactor
to operate, have the side benefit of inhibiting NOx formation during the
combustion event. This benefit is attributable to the lack of oxygen avail-
ability and the lower flame temperature of such mixtures.
Because of the operating principles it incorporates, Device 244 would appear
to have capability for controlling all three pollutants.
3.2.1.1 Physical Description
Figure 3-9 shows a cutaway view of one of the later models of Device 244. The
assembly consists of an outer shell in which a tubular core is mounted with a
shield to insulate the core from the outer shell. This configuration resulted
from fundamental reactor design criteria established by the developer as a
result of his development effort (Reference 71).
HEAT SHIELD
KLACTOR CORE
EXIT HOLES FROM CORE
EXHAUST PORT & FLANGE
XHAUST TO MUFFLER EXHAUST GAS INLET TO CORE
Figure 3-9. DEVICE 244 TYPE V THERMAL REACTOR
PHYSICAL CONFIGURATION (REFERENCE 72)
The size of the reactor was based on the largest volumetric shell which would
fit in an engine compartment without altering any of the major structural
components of the vehicle. The reactor size meeting this criterion was a
cylindrical shape with an external diameter of 4.5 inches and an overall
length of approximately 22 inches.
3-32
-------
The internal design was based on developmental studies which showed that an
inner core was necessary to mix the exhaust gas with injected air. These
studies showed also that the mixing function of the core could be imple-
mented in two ways:
a. By incorporating baffles in the core to induce
turbulent mixing.
b. By locating and sizing of inlet and outlet passageways
to induce mixing by controlled gas flow within the core.
Based on emission tests, the second approach was found to be more effective.
Subsequently it was found that further effectiveness could be achieved by
placing shields around the core to provide additional heat insulation and
mixing. This reactor configuration is known as Type III.
An auxiliary air injection system is used to supply the air needed to oxidize
the exhaust gas. The air system is usually a Saginaw Steering Gear positive
displacement pump driven by the engine. The air is supplied to the exhaust
ports through a manifold with an individual air tube for each port. This is
the system typically used on cars incorporating air injection as the means of
exhaust control. A gulp-type air bypass valve is used to divert the injected
air to the intake manifold during the initial period of deceleration. (1)
The material composition of the reactor is still being investigated (Reference
73), to determine a material capable of withstanding the oxidizing and cor-
rosive thermal (1,400°-1,800°F) environment that exists within the reactor.
Materials such as Incoloy 800 and 310 stainless steel are considered by the
developer to be potential candidates as far as durability is concerned, but
are relatively expensive because of the quantities of nickel they contain.
For lower cost, iron-base, heating-element type alloys which typically con-
tain 12 to 25 percent chromium and 3 to 6 percent aluminum are being investi-
gated. The composition of some of the more promising of these alloys is shown
in Table 3-16.
(1) The bypass-type valve sometimes incorporated on air injection systems can-
not be used with the reactor. Higher emissions would result during
deceleration because this type valve, in bypassing to the atmosphere rather
than the intake manifold, would not provide the extra air needed for
combination of the overrich fuel mixture which develops during the initial
periods of deceleration (Reference 71).
3-33
-------
Table 3-16. COMPOSITION OF CANDIDATE ALLOYS FOR
DEVICE 244 RICH THERMAL REACTOR (REFERENCE 73)
ALLOY
406
A
B
C
D
PERCENT
CHROMIUM
12
12
15
15
22
ALUMINUM
4
3
4
5.5
5.5
3.2.1.2 Functional Description
The basic purpose of Device 244 is to oxidize CO and HC compounds of the
exhaust gas to carbon dioxide and water. Figure 3-10 shows the exhaust gas
flow through the reactor during the oxidation process, along with the entry of
air from the air injection system.
TiXHAUST GAS—i
..p& m
ty&KawamBKUEamauvnL}
OUTER SHELL
RADIATION
SHIELD
TO EXHAUST SYSTEM
Figure 3-10. DEVICE 244 EXHAUST GAS FLOW THROUGH RICH
THERMAL REACTOR (REFERENCE 71)
3-34
-------
As the piston nears bottom dead center on the power stroke, the exhaust
valve begins to open. Then, as the piston moves up on the exhaust stroke,
the exhaust gas is mixed with the injected air and expelled through the
exhaust port directly into the reactor inlet tube. The reactor inlet tube is
connected to the reactor core, into which the air and exhaust gas flow.
Upon entering the core, the air and gas from adjacent inlets have a common
set of exit ports by which to leave the core. As the gases meet at these
exit ports, the intermixing process, which began in the engine cylinder, is
accelerated. The core and exit ports are sized so as to restrict the passage
of the gases to the extent that excessive exhaust backpressure does not
develop. The objective is to hold as much of the gases as possible within the
core as long as possible so as to subject them to thermal oxidation.
The principal source of heat for the reactor is from the oxidation process
itself. The high concentrations of CO and HC resulting in the exhaust gas
from the rich fuel mixture are readily oxidized at the right temperature.
As they leave the combustion chamber, oxidation is already in process.
As CO and HC convert to carbon dioxide and water, heat is liberated. The core,
heat shield, and outer shell insulation are designed to have minimum thermal
capacity. As the hot fuel-rich gases mix with air within the chamber,
oxidation is initiated and the heat liberated is retained by the inner reactor
components. With balanced reactor volumetric capacity gas flow, and heat
insulation, an optimum oxidation temperature of about 1,650°F is maintained.
The gas temperature has to be maintained above a minimum level ranging between
1,200°to 1,400°F, for effective oxidation of the unburned exhaust CO and HC
(Reference 71). To prevent the temperature of the exhaust gas entering the
reactor from being below this minimum, particularly during cold-start idle
and low speed cruise, retarded spark at idle and off-idle is used with ther-
mostatic control to resume spark advance when the engine coolant is above
140°F. This has been found to warm up the reactor faster.
When Device 244 is installed on engines which use exhaust gas to heat the
intake manifold to promote fuel vaporization during cold start, the flow of
the exhaust gas is changed so that the gas goes to the reactor first and then
to the intake manifold. This is to make sure that the exhaust gas entering
the reactor is at its hottest, rather than cooled down from circulating
first through the intake manifold.
The flow of exhaust gas from the reactor to the intake manifold is illustrated
in Figure 3*-ll. To make this modification, the passageway through the cylin-
der head between the exhaust valve and the intake manifold is blocked.
Exhaust gas to warm the intake manifold is then routed from the exit of the
reactor to the manifold.
3-35
-------
EXHAUST
CROSSOVER
PASSAGE
HEAT RISER
VALVE
Figure 3-11. DEVICE 244 RICH THERMAL REACTOR AND INTAKE
MANIFOLD HEAT INTERFACE (REFERENCE 71)
The amount of air required by the reactor from the air injection system
varies according to the degree of engine warmup and operating mode. During
cold start, when the air-fuel mixture is particularly rich because the choke
is operating, more air is required than when the engine is warmed up and
the air-fuel ratio is near stoichiometric. The developer has found that the
standard air injection system has to be operated at a pump-to-engine rpm
ratio of 1.25 to 1.50 to achieve an optimum compromise between the different
air supply requirements of the cold and the hot engine.
Since the engine has to have extra air in the intake manifold at the start
of deceleration to prevent backfiring of the residual, unmixed fuel, the gulp-
type antibackfire valve is required when the standard air injection system is
used. This valve injects air to the intake manifold during deceleration. The
air injected during this diversion is mixed with the remaining fuel in the in-
take manifold, and the resulting air-fuel mixture is then drawn into the cylin-
der for normal combustion. This prevents the reactor from being loaded up with
unmixed fuel during deceleration at a time when the air injection system is un-
loading and, therefore, not supplying air to the reactor. As discussed later in
paragraph 3.2.1.4, if too rich a fuel mixture enters the reactor when it is at
operating temperature, the mixture could ignite, damaging the reactor.
To complete its flow through the reactor (Figure 3-11) , the air and exhaust
gas mixture, still undergoing oxidation, flows out of the inner core through
the exit ports into the annular space between the core and its concentric heat
shield. This narrow passageway reduces the gas volume-to-surface-area ratio
to expose as much of the exhaust gas as possible to thermal oxidation. The
gas then flows through the annular space between the heat shield and the con-
centric outer shell, and exits into the exhaust pipe.
3-36
-------
Thus, in operating principle, the inner core functions as a mixing chamber
and the passages between the core, the heat shield and the outer shell
functions as a thermal zone for the oxidation process. Because of the 1,000°F
heat differential between the core-heat-shield assembly and the insulated
outer shell, the inner assembly is designed so that it can expand and contract
without stressing itself or the shell. As noted in Figure 3-10, the heat
shield is attached to the core, which in turn is mounted inside the shell
by pins at each end. During thermal expansion or contraction these pins
slide freely in the shell end-cap bearings into which they fit. Similarly
the inlet tubes from the exhaust port to the inner core are loose fitted
into the core so that they can expand and contract and so that the core can
as well.
The developer has also found that the effectiveness of a thermal reactor is
influenced by the distance the exhaust gas has to travel before it enters the
reactor and by the insulating properties of the passageway. In general, the
longer the passageway, the cooler the exhaust gas will be when it enters the
reactor, and the lesser the gas is oxidized. Special exhaust port inserts
are used to insulate the exhaust gas from the water-cooled exhaust port
passage of the engine. Figure 3-12 shows two inserts which eliminate the pro-
jecting air injection tube of the standard auxiliary air supply system, and
a third insert that simply insulates the passageway. Each of the three sys-
tems was effective in providing further emission decrease, particularly CO.
These decreases were accompanied by an increase of 25° to 70°F in the average
temperature of the reactor core (Reference 71).
3.2.1.3 Performance Characteristics
The developer has performed many emission tests on Device 244 and has parti-
cipated in HEW/NAPCA test programs. Figure 3-13 illustrates in general the
emission reduction characteristics of a thermal reactor. The CO and
HC emission levels of the vehicle with the standard air injection system
operating, but without the reactor installed, are shown for comparison. (1)
Both tests were performed to the 1970 Federal Test Procedure (Reference 15).
An 83 percent reduction in HC and a 67 percent reduction in CO are indicated
by use of the thermal reactor.
(1) The vehicle was reported as being a standard sedan equipped with an 8-
cylinder, 300-CID engine with 2-barrel carburetor and automatic transmis-
sion, representative of a high percentage of total U.S. vehicle production
(Reference 71).
3-37
-------
AIR
n
(a) Standard air injection
AIR
50 HOLES
0.031 "DIAMETER
(b) Single-wall insulation
AIR
(c) Double-wall insulation
with annular injection
(d) Single-wall insulation
with annular injection
Figure 3-12. DEVICE 244 RICH THERMAL REACTOR EXHAUST PORT INSERT
ALTERNATIVE CONFIGURATIONS (REFERENCE 71)
The drop in emissions indicated by both systems from the first to second test
cycles is attributable to the warming up of the engine. The ability of a
reactor to control exhaust emissions is measurable in part by how fast it
can warm up so that the oxidation process can begin. Temperature measure-
ments made during the 1970 Federal Test Procedure indicate that the core
temperature reaches minimum oxidation temperature (1,200°F) less than one-
third of the way through the first 7-mode cycle, from a cold start.
3-38
-------
300
0.200
CO
i
o
g 100
REACTORS
I 2 3 4 S 6 7
FEDERAL TEST PROCEDURE CYCLE NUMBER
UJ
o
£'
a.
x
o
S
AIR INJECTION
SYSTEM
TYPE
REACTORS
0— — ©
12 3 1 5 6 7
FEDERAL TEST PROCEDURE CYCLE N-JMBSR
Figure 3-13. DEVICE 244 RICH THERMAL REACTOR EMISSION REDUCTION CHARACTER-
ISTICS COMPARED TO STANDARD AIR INJECTION (REFERENCE 71)
Figure 3-14 shows the core temperature profile for the 7-mode cold start tests.
The high temperature peak that occurred during the first cycle appears to be
due to the oxidation of the larger amounts of CO and HC which result from
the choke-enriched fuel mixture during cold start. The choking, although
causing higher emissions, also provides the rich mixture which heats up
the reactor quickly.
1800
2 -H«- 3 4« 4 -«+•- 5 -«f- 6 -«+•- 7
FEDERAL TEST PROCEDURE CYCLE NUMBER
6 8 10
TIME, MINUTES
12
14
16
Figure 3-14. DEVICE 244 RICH THERMAL REACTOR TEMPERATURE PROFILE
FOR ONE 7-MODE CYCLE (REFERENCE 71)
3-39
-------
Emission tests performed by HEW/NAPCA with Device 244 used in combination
with exhaust gas recirculation, carburetor modifications, special exhaust
systems, and particulate traps indicated average emission levels meeting
1974 Federal Standards of 3.4 gm/mi HC, 39 gm/mi CO, and 3.0 gm/mi NOx. The
average percentage reductions for this device configuration were 80 percent HC,
44 percent CO, and 65 percent NOx, when tested using nine Federal emissions-test
cycles and the constant volume sampling technique (References 16, 74, and 75).
This device configuration is described in Section 9, as an emission control
combination (Device 469).
3.2.1.4 Reliability
Reactor durability may be a significant factor in the overall cost effective-
ness of Device 244. The service life of a reactor has been found to depend
largely on whether the core heat shield and insulation can withstand the
oxidizing, erosive environment that exists within the reactor during oper-
ation (References 2 and 71). Tests by the developer have indicated that none
of the commercially available alloys have adequate oxidation resistance.
Superalloys were found to be more satisfactory, but expensive for application
to an automotive exhaust reactor.
The principal manifestation of reactor degradation is the erosion of the core
in the area opposite the exhaust gas inlet. The mechanism of the erosion
appears to involve oxidation of the surface of the metal, followed by erosion
of the oxidized area as a result of particulate matter impingement at high
velocity (Reference 71). The solution to the problem, according to the de-
veloper, may be to change the geometry of the inlet passages to prevent high
velocity impingement and to use erosion resistant coatings in the local areas
of the core most subject to oxidation and erosion.
Erosion-resistant materials which have indicated sufficient oxidation resistance
for extended life are those which have had a' layer of nickel aluminide applied
by the plasma-jet spraying technique, followed by aluminum dipping. The
aluminum dipping appears to provide adequate oxidation resistance and the
plasma-jet spray application of nickel aluminide enhances this resistance-
Design configuration changes by the developer to decrease the erosion attri-
buted to exhaust impingement have included deletion of the baffles in the core.
These were found to be located at the point of maximum erosion. Also, revision
of the exhaust port and reactor inlet tube passageways has been considered, to
eliminate concentrated impingement of the exhaust gas on the core (Reference 71).
Patches of oxidation resistant material also are being used to protect the
impingement area.
While the oxidation and erosion problem appears to depend mainly on the inherent
susceptibility of the reactor core metal to oxidation, the presence of lead in
the gasoline apparently can increase this susceptibility in the low-cost alloy
steels at the high temperatures at which reactors operate. These steels usually
have insufficient strength to withstand long-term exposure to the reactor's ther-
mal environment. With the high-temperature materials such as Inconel 601, the
presence or absence of lead appears to make no difference (Reference 2).
3-40
-------
The oxidation/erosion effects of leaded fuels appear to be directly related to
temperature and the amount of lead. Materials testing with different fuel com-
positions of lead, halide, and phosphorous have indicated that less erosion
occurs with nonleaded gasoline, but that the magnitude of erosion increases with
increased temperature. As shown by Figure 3-15, the rate of increase for low-
lead gasoline and gasoline with 3 gm/gallon lead is approximately the same.
The significance of the data reflected in this figure is that at temperatures
approaching 1,700°F, alloy weight loss from erosion does not appear to be parti-
cularly sensitive to fuel composition (Reference 2). As shown by Figure 3-16b,
under normal cruise conditions the reactor core temperature could be limited to
1,750°F, with throttle- and vacuum-controlled air diversion incorporated. This
form of control would divert injected air from the exhaust system during vehicle
operating modes in which the air-fuel mixture is richer than usual. Since these
modes are associated with high cruise speeds and high loads when exhaust
emissions might be high, the effect of air diversion on the emission reduction
effectiveness of the reactor should be determined before using this approach to
reactor temperature control.
BARE SANDBLASTED SPECIMENS
THICKNESS
4.5
4.0
3.5
3.0
25
LOSS-
MILS/50 HRS. 2-°
1.5
1.0
.5
0
Km/GAL LEAD, HALIOE
(MM OR AM), PHOSPHORUS
3 gm/GAL LEAD
0.5 gm/GAL LEAD,
HALIDE (MM),
OR NON-LEADEO
1720
1760 1800
MAX. CYCLE TEMP.-°F
1840
Figure 3-15. EFFECT OF FUEL VARIABLES ON AVERAGE THICKNESS LOSSES
OF OR-1 ALLOY DURING CONTINUOUS THERMAL CYCLING (REFERENCE 2)
3-41
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2200
1000
40 60
SPEED, MPH
100
2200
2000
u
9- ieoo
£ 1600
u
i-
u 1400
O
u
1200
1000
AIR INJECTION
AIR DIVERTED
20
40 60
SPEED. MPH
Grey area indicates "Light-Off" limits of Car Make A equipped with Type I exhaust
manifold reactor system. Intermittent or trace "Light-Off" occurs in the light grey
zone while severe "Light-Off" occurs in the darker grey zone.
80
100
(a) With and Without Air Injection
(b) With Air Injection Diverted
Above 80 mph and Below
7 Inches Hg.
Figure 3-16. DEVICE 244 RICH THERMAL REACTOR CORE EQUILIBRIUM TEMPERATURES
FOR VEHICLE OPERATING MODES (REFERENCE 71)
The preceding reliability factors concern reactor durability under high temp-
erature operation. Another potential reliability problem is that of reactor
light-off. "Light-off" is the condition which exists when the air-exhaust
mixture within the reactor actually begins to burn as a result of engine mis-
fire or a particularly rich fuel mixture. As noted in Reference 71, light-off
generally is associated with large volume, highly efficient reactors. Since
temperatures in excess of 2,400°F can be reached quickly with light-off, this
condition must be prevented or catastrophic failure of the reactor may occur.
Figure 3-16 indicates the core temperatures and engine modes at which light-off
could occur, given a misfire. As indicated by this figure, light-off is dependent
on the vehicle operating modes in which the fuel mixture is rich; and on the
reactor being operated with air injection during those modes. The combination
of wide open throttle or heavy engine loading with air injection to the reactor
provides the conditions for light-off to occur.
Figure 3-17 shows the condition of a Device 244 reactor after one hour of sus-
tained light-off at 70 mph. Disassembly of the reactor after the test revealed
that the core had failed catastrophically and that the insulating liner was
severely damaged. A large section of the core had melted, indicating that
temperatures exceeding 2,500°F, the nominal melting point of the core metal
(Alloy F), must have occurred (Reference 71).
3-42
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II
Cores and insulating liner of Type I exhaust manifold
reactor installed on Car Make A after one hour of operation
at 70 mph, wide-open throttle with "light-off" induced by
shorting two spark plugs.
Figure 3-17. CONDITION OF DEVICE 244 RICH THERMAL REACTOR COMPONENTS
AFTER ONE HOUR OF LIGHT-OFF (REFERENCE 71)
The reliability of the reactor is susceptible to a variety of other engine mal-
functions, such as a stuck choke, a stuck power enrichment valve, or other
carburetor malfunctions which could cause rich fuel mixtures and high tempera-
tures. Distributor timing over-retarding and leaking exhaust valves could load
up the reactor with excess fuel as well. According to the developer, some form
of controlled air injection rate appears to be the means by which most of these
excess-temperature related factors could be controlled (Reference 71).
It is the developer's position that the Device 244 thermal reactor has the re-
liability to control emissions for 100,000 miles of normal operation, but that re-
actor reliability still has to be proved trouble-free under the wide variety of
tests used by vehicle manufacturers. It would appear therefore that any use
3-43
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or accreditation of the Device 244 reactor for retrofit would be contingent on
restricting vehicle operation to the reliability constraints of the device, or
on partially deactivating the device during the critical driving modes.
3.2.1.5 Maintainability
Assuming that the device is operated within the limits prescribed for re-
liability, it should require no planned maintenance of the reactor itself.
Since an air pump is required and these usually have an air filter it is
assumed that cleaning of the filter would be required once every 12,000 miles.
The amount of time required to clean the filter is estimated to be 0.25 hour.
Preventing any particulate matter from entering the exhaust system is necessary,
because of the susceptibility of the reactor core to erosion from the high
velocity impingement of particulates (refer to paragraph 3.2.1.4).
3.2.1.6 Driveability and Safety
3.2.1.6.1 Driveability. The developer has reported that there are no drive-
ability problems that would be apparent to the average driver; however, some
decrease in vehicle acceleration time has been measured (Reference 71). The
developer attributes this, to the greater pressure drop in the exhaust gas
across the reactor, than occurs with the standard exhaust manifold system.
This pressure drop has been measured as being 2.5 times more than that of the
standard manifold.
The effect of this pressure drop is to increase exhaust backpressure. This
reduced maximum power output of the engine of the developer's test vehicle
by as much as 6 percent at the 4,500-rpm rated engine power. Acceleration of
this vehicle with different configurations of the reactor system is shown in
Table 3-17. The reactor caused an increase of about one second (8%) in the 0-to-
60-mph acceleration time.
The developer attributes the increased backpressure to the increase in the gas
volume and temperature resulting in the reactor from the injection of air and
the consequent oxidation process. The developer's approach to improving ac-
celeration with the reactor installed has been to divert air from the reactor
during acceleration and to replace the standard muffler with a resonator to
improve exhaust flow.
Other than the acceleration loss, the reactor apparently has caused no drive-
ability problems. Cold starting and driving and general hot driveability have
been satisfactory.
3.2.1.6.2 Fuel Economy. An increase in fuel consumption has been measured in
vehicle tests with the reactor installed. This is attributed to the rich car-
buretion generally associated with thermal reactors of the Device 244 type.
3-44
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Table 3-17. DEVICE 244 RICH THERMAL REACTOR DEVELOPER ACCELERATION
TEST RESULTS (REFERENCE 71)
Car Make A(l)
Wide-open- throttle, Level Road
Acceleration Time in Seconds
0-50 mph
Standard Manifolds Without Air Injection
Standard Manifolds With Air Injection
Type
Type
I
I
Reactors Without Air Injection
Reactors With Air Injection
Type I Reactors With Air Injection,
Air Diverting Valve, and Resonator
in Place of Muffler
(1)
Defined by the developer as
V-8 engine of approximately
automatic transmission, and
9
10.
10.
10.
9.
4
3
0
8
4
0-60
13
14
14
15
13
mph 30-60 mph 50-70 mph
.3
.4
.1
.4
.3
1965-67 standard
300 CID, 2 -barrel
power steering.
8.
9.
9.
9.
8.
5
3
0
4
7
2-door sedans,
carburetor .
9.
9.
9.
10.
9.
1
9
4
2
2
with
Table 3-18 shows the results of fuel consumption tests performed by the devel-
oper. The "rich" carburetor caused a 17 percent decrease in miles per gallon
using the 1970 Federal Test Procedure. The "lean" carburetor caused a 6 percent
decrease in miles per gallon. The "lean" carburetor, however, had higher
emissions of 60 ppm HC and 0.80 percent CO. This loss in fuel economy would in-
crease the recurring operational costs with the device, as noted in paragraph
3.2.1.8.
3.2.1.6.3 Safety. There appear to be no safety problems with Device 244.
Temperature measurements reported by the developer indicate that the exterior
surface of the reactor is less hot than the standard exhaust manifold under
comparable conditions. The temperature at the reactor outlet is greater than
the standard exhaust manifold (1,430° to 1,600°F versus 1,140° to 1,260°F).
This temperature, two feet down the exhaust pipe, decreases to where it is about
the same as the temperature of a standard exhaust system.
The developer indicated that the higher temperature should increase the life of
the muffler and tail pipe, which usually fail due to cold corrosion (Refer-
ence 71).
3-45
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Table 3-18. DEVICE 244 RICH THERMAL REACTOR DEVELOPER FUEL CONSUMPTION
TEST RESULTS (REFERENCE 71)
Car Make A (1)
Tests on Clayton Emission Test Dynamometer
Fuel A
Fuel Economy,
Emission Control System
Dynamometer Set to 12
None (Standard 1967)
1967 Air Injection System
Reactors + with Air Injection System Carburetor
Reactors + with "Rich" Carburetor (2)
Reactors* with "Lean" Carburetor (3)
Dynamometer Set to 26
None (Standard 1967)
1967 Air Injection System
Reactors + with Air Injection System Carburetor
Reactors + with "Rich" Carburetor
Reactors + with "Lean" Carburetor
Cyclic*
HP at 50
15.7
15.0
15.3
13.4
14.6
HP at 50
14.4
13.9
14.1
11.4
13.7
15**
mph
24.3
22.6
21.3
14.5
16.5
mph
21.6
21.0
16.3
14.1
18.5
* Federal Emission Test Cycle ** Steady Speeds, mph +
(1) Defined in Table 3-17
(2) 11.0:1 air-fuel ratio
(3) 11.5:1 air-fuel ratio
30
24.4
27'. 6
25.2
22.8
26.0
20.4
20.7
21.3
17.9
24.2
Type m
mpg
45
20.0
21.3
21.1
20.0
22.1
16.1
15.4
16.1
14.7
17.2
60
16.8
17.0
18.2
14.2
19.5
11.1
10.2
10.6
11.3
11.1
Reactors
3.2.1.7 Installation Description
A typical installation of Device 244 is shown in Figure 3-18. The installation
of this device consists basically of the following phases:
a. Replacing the standard exhaust manifold with the thermal
reactor manifold (two for 8-cylinder engines).
b. Installing the correct engine-rpm-drive ratio air pump
(1.25:1 or.1.50:1) and air injection manifold (if not al-
ready standard equipment for the vehicle being converted).
c. Blocking the exhaust passage to the intake manifold and
connecting the reactor manifold heat line to the intake
manifold.
d. Adjusting the carburetor to 11.0:1 air-fuel ratio.
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AIR INJECTION
MANIFOLD
THERMAL
REACTOR
Figure 3-18. DEVICE 244 THERMAL REACTOR INSTALLATION (REFERENCE 72)
Table 3-19 lists the installation steps generally required to implement these
phases, along with the tools and the amount of time required, as.-Mm-ing an
eight-cylinder vehicle. The installation should be made by an experienced
automotive mechanic. The installation of an air injection system is assumed
to be a requirement.
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Table 3-19. DEVICE 244 RICH THERMAL REACTOR INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove existing exhaust manifold
2. Remove intake manifold
3. Install air injection manifold
4. Install air pump bracket and pump
(verify correct ratio pump pulley
for a 1:25:1:50 pump to engine
pulley ratio)
5. Block intake manifold exhaust gas
circulation passageway
6. Install exhaust port insulation
7. Install thermal reactor manifolds
8. Replace intake manifold
9. Connect air pump hose to injection
manifold and reactor hose to intake
manifold
10. Adjust carburetor to 11.0:1 air-
fuel ratio and test.
11. Inspect exhaust system for leaks
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools
Electric drill, tap, and
hand tools
Plate, drill, tap and
hand tools
Hand tools
Hand tools
Hand tools
Hand tools and engine
analyzer
Total Time
TIME
(MIN.J.
45
30
180
90
15
15
45
30
10
15
5
8.0 hrs
3.2.1.8 Initial and Recurring Costs
Table 3-20 sets forth the initial and recurring costs estimated for Device 244
based on the installation requirements defined in Table 3-19 and the increased
fuel consumption which the device indicates. Initial costs for a six-cylinder
vehicle would be about $175 less than the average eight-cylinder vehicle, be-
cause only one reactor manifold would be required. Recurring costs would be
about the same.
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Table 3-20. DEVICE 244 RICH THERMAL REACTOR INITIAL AND
RECURRING COSTS
ITEM
Initial Cost:
Materials:
1. Kit
2. Miscellaneous
Labor:
1. Installation
DESCRIPTION
Thermal reactor with
air injection system
(Two for 8-cylinder
engine and one for
6-cylinder engine)
Brackets, hoses,
fasteners
Table 3-19
LABOR HOURS OR
ITEM QUANTITY
As required by kit
8 hrs for 8-cylinder
engine
4 hrs for 6-cylinder
engine
Total Initial Cost (1)
50,000-Mile
Recurring Cost:
Material:
1. Fuel
2. Filter
15 percent average
increase in con-
sumption over the
national average of
12.5 mpg at 10,000
miles per year for
50,000 miles
Inspect/clean
500 gallons X $0.35
per gallon
0.25 hr
Total Recurring Cost
Total Cost
COST
(DOLLARS)
6 Cyl
125.00
25.00
50.00
200.00
8 Cyl
250.00
25.00
100.00
375.00
210.00
3.13
213.13
413.13
588.13
(1) $85 less if an air injection system is not required.
3r49
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3.2.1.9 Feasibility Summary
Although Device 244 has been demonstrated as an effective means of reducing
vehicle exhaust emissions of CO and HC, it currently appears to require more
development before it can be considered technically feasible. Its suscepti-
bility to internal oxidation and erosion would possibly impose restrictions on
vehicle operating modes, if the device were incorporated. The alternative of
limiting device operation by leaner fuel mixtures and by air diversion would
require a determination as to how much emission reduction effectiveness would
be lost, before such restrictions could be accepted from an emissions standpoint.
The high initial and recurring costs are perhaps the decisive factors in evalu-
ating the device for its retrofit feasibility. Unless the initial costs were
reduced substantially, the device would be difficult to justify on a cost ef-
fectiveness basis. If the device were limited to later model vehicles with air
injection systems, the initial cost would still be high for a retrofit device.
It would appear that only a major redesign based on new breakthroughs in low-
cost reactor materials would lower the initial costs to a reasonable level.
Because of the device's high costs and its questionable reliability under all
vehicle operating conditions, this device would appear to be questionable as a
retrofit candidate at this time.
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3.2.2 Device 463: Rich Thermal Reactor with Exhaust Gas Recircul3tion and Spark
Retard
Device 463 combines exhaust gas recirculation (EGR) and spark retard to control NOx
with post-combustion thermal reaction to control CO and HG. The reactor is the pro-
duct of extensive developmental effort, as reported in Reference 101, and also has
been tested by EPA (Reference 102). The following system description is based on
these data sources.
3.2.2.1 Physical Description
The reactor subsystem is shown in Figure 3-19. The reactor consists of a replace-
ment exhaust manifold and an air-exhaust mixing chamber. The manifold incorporates
CLEAN
EXHAUST
EXHAUST
b.
EXHAUST
Figure 3-19. DEVICE 463 RICH THERMAL REACTOR MODEL II CONFIGURATION
(REFERENCE 101)
flame holders opposite each exhaust port. The flame holders are made of stainless
steel sheet perforated with 1/8-inch-diameter holes and extending halfway across the
exhaust port. The manifold also incorporates air injection tubes which extend
through the flame holders.
The reactor section is of a torus configuration that is 5.5 inches in diameter and
3.0 inches wide. The volume of the torus is 71 cubic inches and the surface-to-
volume ratio is 1.35.(1) The reactor is made from Type 310 stainless steel.
(1) The reactor shown in Figure 3-19 is a second generation model. This model was
designed to reduce surface-to-volume ratio. This was done to reduce flame
quenching and heat losses at the reactor walls, and thereby enable the reactor
to warm up faster (Reference 101).
3-51
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For V-8 engines, a reactor is installed on each cylinder bank. In the developer's
tests, each reactor was insulated with about 1/2 inch of refractory felt coated
with asbestos cement. Air to the reactors was supplied through balanced air injec-
tion manifolds by a single automotive air pump driven by the engine. Pump speed
was approximately 2.5 times engine speed.
The engine spark timing is set at the manufacturer's specification; but vacuum ad-
vance is inactivated, unless the exhaust pipe temperature indicates that the reactor
is warmed up and the speed is above 20-25 mph cruise.
Exhaust gas recirculation of approximately 12 percent of engine intake air is used.
The exhaust gas is taken near the muffler and routed through a finned cooling tube
to the carburetor above the throttle plate. A diaphragm valve connected to the vac-
uum advance line controls the EGR; thus, EGR is off when the vacuum advance is off.
The exhaust gas crossover normally used to heat the intake manifold is blocked on
one side to equalize the temperature of the two reactors.
An automatic choke was designed by the developer to disengage the choke when reactor
temperature indicates that the reactors are warmed up and also when the throttle is
opened. A fast idle cam modification is also used. This provides a fast idle speed
of 1,700-1,900 rpm in neutral after starting, but disengages upon the first throttle
movement. Fuel rich carburetion is provided by enlarged idle, off-idle, and main
jets.
3.2.2.2 Functional Description
The basic function of the reactor subsystem is to provide the air and thermal environ-
ment in which the CO and HC constituents of the exhaust gas can be oxidized to carbon
dioxide and water. As noted for Device 244 (paragraph 3.2.1), the effectiveness of
a thermal reactor in producing the high temperature (1,400-1,900°F) needed to support
oxidation is influenced by the speed with which the reactor can heat up during en-
gine cold start operations, when emissions are usually high. The purpose of the
flame holders is to stabilize the flame at the exhaust outlet during engine start-
up when the choke is used. The stabilized flame causes the oxidation process to be
initiated and thereby reactor warmup is accelerated. The flame holder grid creates
eddies which heat the grid locally, igniting the fuel rich exhaust gas. When the
choke is disengaged, the flame goes out because the air-fuel ratio returns to normal;
but by this time the reactor is warmed up.
Figure 3-20 shows the reactor warmup time with and without the flame holders. The
gas temperature was recorded at the exhaust outlet using the 1968 Federal Test Pro-
cedure (Reference 14). The developer reported that without the flame holders,
flameout occurred when the car was put in gear and again during the acceleration
from 15 to 50 mph (Reference 101).
According to the developer, most of the thermal reaction takes place as the gases
swirl through the reactor. The gases enter the torus and flow around it to exit
through a slot in the central plenum and thence into the exhaust pipe. The slot is
positioned so that the gases must flow at least halfway around the torus and also
so that a portion of the gas goes past the slot to mix with incoming gas. The
back-mixing is intended to initiate reaction in the incoming gas and to mix the in-
jected air.
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2000
1600
1200
0 T.O 40 60 80 100 120 140 160
ELAPSED TIME (1968 FTP) - sec.
Figure 3-20. EFFECT OF FLAME HOLDERS ON DEVICE 463 RICH THERMAL REACTOR
WARMUP TIME DURING 1968 FEDERAL TEST PROCEDURE
(REFERENCE 101)
The distributor vacuum advance is disconnected below 20-25 mph, so as to speed
reactor warmup and to enhance oxidations at low speed and idle when emissions are
high. This also tends to reduce NOx because of the lower peak flame temperature
during combustion.
Exhaust gas recirculation is used to provide NOx control whenever the vacuum advance
is operating. EGR was not used below 20-25 mph because, according to the developer,
it increased CO and HC. It was not desired during warmup, because it prevented the
warmup flame from being established quickly.
Fuel rich carburetion is used to speed reactor warmup and to sustain reactor oxi-
dation temperature. As is typical of rich thermal reactors, an excess of CO and HC
in the exhaust is required for the oxidation process to be effective.
3.2.2.3 Performance Characteristics
The developer found that the reactor was fully operational within 40 seconds after
a cold start. An operating temperature of 1,500°F was found adequate to reduce CO
and HC so that very little of these pollutants are emitted with the exhaust gas.
Exceptions occur when the engine is choked and there is insufficient air, or when
very high exhaust flow rates occur before the exhaust pipe is hot enough to sustain
the reaction (Reference 101). Although the developer reported no vehicle baseline
emission data, average emission levels measured with the 1972 Federal Test Proce-
dure (Reference 3) met the 1975 emission standards, as shown in Table 3-21.
The results of emission tests performed by EPA were much the same, except that CO
exceeded the 1975 standard. These results are shown in Table 3-22.
3.2.2.4 Reliability
The developer reported (Reference 101) that 1,950°F, which was reached at 60 mph
cruise speed, is considered the upper limit for reactor durability. In the exper-
imental configuration tested, no overtemperature control was used. The developer
stated, however, that it would be necessary to have such control to protect the
reactor from the excessive temperatures that engine malfunction could cause. Mal-
function examples are a stuck choke or persistent spark plug misfire, which could
3-53
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Table 3-21. DEVICE 463 RICH THERMAL REACTOR EMISSION LEVELS COMPARED TO 1975
STANDARDS (REPORTED BY DEVELOPER IN REFERENCE 101)
EMISSION LEVEL
1975 Standards
Device 463 (1)
POLLUTANT (GM/MI)
HC
0.46
0.08
CO
4.7
3.7
NOx
3.0
0.72
(1) Average of four tests performed to the 1972 Federal Test Pro-
cedure (Reference 3) on a 1968 Chevrolet Bel Air with 307-CID
V-8 engine.
Table 3-22. DEVICE 463 RICH THERMAL REACTOR EMISSION LEVELS REPORTED BY EPA
(REFERENCE 102) (1)
EMISSION TEST
2 June 1971
23 June 1971
24 June 1971
POLLUTANT (GM/MI)
HC
0.2
0.1
0.1
CO
6
5
5
NOx
0.6
0.6
0.6
(1) Results obtained by the 1972 Federal Test Procedure (Reference
3) with Device 463 on a 1971 Ford LTD with a 351-CID V-8 engine
and automatic transmission.
supply too much fuel to the reactor, causing excessive heat. The developer's
approach to preventing this problem would be to divert the air supplied to the
reactor by the air injection system.
The effects of fuel properties have not been studied by the developer. The perform-
ance data were obtained with commercial fuels.
3.2.2.5 Maintainability
Assuming that the reactor has adequate service life reliability, there should be no
maintenance required on this part of the overall Device 463 system. If the air
pump has an air filter, it would require cleaning about every 12,000 miles. Such
maintenance should not exceed 0.25 hour.
3-S4
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3.2.2.6 Driveability and Safety
The developer reported that the combined effects of EGR, exhaust backpressure, and
rich air-fuel ratio increase the time to reach a given speed. Backpressure increase
caused by the reactor is indicated by Table 3-23.
Table 3-23. DEVICE 463 RICH THERMAL REACTOR EXHAUST BACKPRESSURE
REPORTED BY DEVELOPER (REFERENCE 101)
VEHICLE CONFIGURATION (1)
Device 463 with Muffler
(Inches HaO)
Muffler Alone (Inches H20)
Percent Increase
CRUISE SPEED (MPH)
IDLE
6
4
33
30
20
11
45
40
40
22
45
50
69
38
45
60
110
72
35
(1) 1968 Chevrolet Bel Air with 307-CID V-8 engine.
These results indicate an average 40.6 percent increase in backpressure. The effect
of this on acceleration, when combined with EGR and rich air-fuel mixture, is shown
in Table 3-24. The developer reported, however, that from a subjective standpoint
the vehicle equipped with Device 463 had acceptable driveability.
Table 3-24. DEVICE 463 RICH THERMAL REACTOR VEHICLE ACCELERATION TIME INCREASE
REPORTED BY DEVELOPER (REFERENCE 101)
PERCENT INCREASE IN WOT ACCELERATION TIME (1)
0-25 MPH
5.6
0-40 MPH
9.0
0-50 MPH
17.2
0-60 MPH
20.5
(1) 1968 Chevrolet Bel Air with 307-CID V-8 engine.
As with most retrofit systems which use a rich fuel mixture to decrease NOx, some
loss of fuel economy may be expected. The developer noted that rich engine opera-
tion is essential to a thermal reactor; and that the use of fuel in excess of that
required by the reactor represents a fuel economy debit solely for the reduction
of NOx. In developer tests of the reactor, the fuel mixture was enrichened to the
maximum ratio that reactor operating temperature would allow. With this maximum
rich fuel mixture, the NOx emissions were low, but fuel consumption was high. The
3-55
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average increase measured for fuel consumption in turnpike and city driving was 19.9
percent (Reference 101).
No data on the safety of the Device 463 reactor were reported.
3.2.2.7 Installation Description
A complete evaluation of the Device 463 installation requirements was not possible
on the basis of available data. The reactor apparently is a complete replacement
assembly for the standard exhaust manifold. Figure 3-21 shows one of the two reactors
installed on a 1971 Ford LTD. The torus size was scaled in proportion to the engine
cylinder displacement (351 CID) for this vehicle by increasing the width from 3 to
3.5 inches.
DEVICE 463
THERMAL REACTORS
Figure 3-21.
DEVICE 463 RICH THERMAL REACTOR INSTALLATION ON 1971 FORD LTD
351-CID ENGINE (REFERENCE 101)
3.2.2.8 Initial and Recurring Costs
System costs for Device 463 could not be estimated because of the lack of complete
system information.
3.2.2.9 Feasibility Summary
Device 463 is apparently still in the development stage and requires additional, test-
ing to verify its overall technical feasibility, particularly its reliability.
emission tests reported thus far indicate that the device effectively and consist-
ently reduces exhaust emissions of CO, HC, and NOx. Whether this effectiveness can
be achieved reliably and within a reasonable cost would have to be determined through
further development effort. The large penalty indicated in fuel economy may be a
3-56
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decisive factor offsetting technical feasibility, unless NOx control is decreased
to the point where the increase in fuel consumption is acceptable.
On older model-year vehicles, the overall system costs may still be prohibitive,
because of the requirement for adding an air injection system. The cost of such
systems is approximately $85. On later model-year vehicles which already in-
corporate air injection, the existing air pump could be used with the reactor. In
most cases, however, carburetor modification would be required to provide the rich
fuel mixture needed for reactor operation. Reactor cost would have to be lower than
may be possible, if overall system costs, including EGR and solenoid valves, are to be
acceptable. It would appear that such costs could only be absorbed in a new model-
year basis. Thus, the device may not be economically feasible for retrofit to used
cars.
The rich thermal reactors described in the preceding paragraphs indicate the major
problems in attempting to control CO and HC exhaust pollutants by high temperature
oxidation. In summary, these problems include the substantial penalty in fuel
economy that results from the need for a rich fuel mixture to initiate and sustain
high temperature oxidation, the additional cost penalty that results from the need
for an auxiliary air supply to support the oxidation process, and the questionable
reliability of reactor materials under the oxidation environment produced by the
fuel and the high temperature.
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3.2.3 Device 468; Lean Thermal Reactor with Exhaust Gas Recirculation
Device 468 attempts to eliminate the problems associated with rich thermal reactors
by means of a thermal reactor that operates on a lean air-fuel mixture. The indicated
advantages of this lean thermal reactor (LTR) are that it operates at temperatures
that are 200 to 300°F below those of a rich thermal reactor, it can be operated with-
out an auxiliary air supply, and it avoids the fuel economy losses which appear to
be characteristic of the rich reactor. These advantages result from the high air-
fuel ratios at which the reactor is designed to operate.
Device 468 has undergone vehicle testing by the developer, and is the only design of
a lean operating system for which configuration and performance details were avail-
able. Although the developer was not located during the retrofit method survey,
design and performance information was obtained from a report on the effect of lead
additives on emission control systems (Reference 2).
3.2.3:1 Physical Description
The Device 468 system consists of the LTR for CO and HC control, an exhaust gas
recirculation (EGR) system for NOx control, and modified carburetion for engine
operation at a lean fuel mixture of approximately 17.5 air-fuel ratio. Spark advance
is adjusted for the best compromise between low exhaust emissions, vehicle drivea-
bility, and fuel consumption.
As reported in Reference 2, the reactor is a cylindrical assembly consisting of a
three-layer shell. The inner layer is an open-tube liner made of 310 stainless
steel. The second or intermediate layer is insulating material. The outer layer
casing is made of 310 or 430 sheet stainless steel.
The LTR combines with EGR for the control of NOx during combustion. The lean air-
fuel operation of the reactor requires a special carburetor that provides high veloc-
ity air-fuel intake and mixing. Use of small, dual, or staged venturies is being
investigated to strengthen the fuel metering signals and to improve the air and fuel
mixing. Consideration has also been given by the developer to use of electronic fuel
injection.
Spark retard is generally used as a supplementary NOx control and also to increase
exhaust gas temperature for the oxidation process in the reactor.
3.2.3.2 Functional Description
At the 17-19:1 air-fuel ratios under which the LTR-EGR device operates, CO and HC
concentrations in the engine exhaust are inherently much lower than with the rich
thermal reactor (RTR) or with conventional carburetion. Because of these lower
concentrations, reaction temperatures are not as high as with the RTR. Oxidation
of CO and HC in the LTR is accomplished between 1,400-1,600°F.
Because of its lower operating temperatures, the LTR-EGR device has less of a dura<-
bility problem, and less expensive materials can be used in manufacturing the reactor
core and gas mixing baffles. The low operating temperatures necessitate, however,
that the reactor be designed for minimum heat loss, so as not to limit the oxidation
process.
3-58
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To achieve satisfactory engine performance at the high air-fuel mixture and its
distribution from cylinder to cylinder has to be precisely controlled. This is the
function of the special carburetor mentioned previously.
3.2.3.3 Performance Characteristics
Table 3-25 shows the results of Device 468 emission tests reported by the developer
and summarized in Reference 2. For comparison, Table 3-26 shows emission results
for the device when operated with auxiliary air injection during cold start. These
results indicate that the device without air injection may be able to meet 1974
Federal emission standards. Percent reduction from vehicle baseline emission levels
were not reported.
The developer reported (Reference 2) that the cold start phase of the 1972 Federal
Test Procedure contributes most of the CO and HC pollutants, and almost half of the
NOx. Estimates are that 78 percent of the HC, 68 percent of the CO, and 48 percent
of the NOx occur during this phase. The relatively low overall emission levels
shown in Tables 3-25 and 3-26 would indicate that the LTR warms up quickly to oxi-
dation temperatures.
3.2.3.4 Reliability
The results of developer tests indicate that overtemperature protection of the LTR
is not required, as it is withtheRTR. Tests have been run with three spark plugs
disconnected without increasing reactor temperature, though with CO and HC increase.
A 50,000-mile service life (MMBTF) has not been demonstrated, but indications are
that the device could achieve this standard.
The basic nature of a lean reactor system indicates less difficulty in obtaining
satisfactory durability than with a rich reactor system. Exhaust gas entering the
reactor from the lean engine contains about 100 ppm HC, 0.1-0.4 percent CO, and
approximately 2-4 percent 02 (without an air pump); therefore, little chemical heat
is generated in the reactor and its ultimate temperature is determined by the extent
to which the heat in the exhaust gas is not lost by radiation. This enables the
lean reactor to operate in a temperature range of 1,400° to 1,600°F, even under
high-speed turnpike conditions. This is a temperature range that good-quality
stainless steels should tolerate well. Tests by the developer indicate that the
lean reactor is not subject to destructive temperature excursions, even (as noted
above) with a continuously misfiring spark plug. Thus, durability should not be
seriously decreased by situations in which engine malfunctions occur.
A developer-modified 1966 Pontiac was driven throughout the United States for over
20,000 miles while being used for a series of demonstrations. Modifications were
similar to those in cars now in use with the LTR-EGR, except that the car was not
equipped with EGR and had a less effective thermal reactor. Another Pontiac incor-
porating EGR and improved thermal reactors accumulated over 30,000 miles in various
types of service including cross-country trips. This car was reported by the
developer to have demonstrated excellent durability characteristics and emission
reduction stability.
The developer provided a modified 1970 Pontiac to the California Air Resources Board
in November 1970 for testing and use in general fleet service. The durability test
mileage of this vehicle at the last reported test point was 12,000 miles. The emis-
sions of this car had good stability, as shown in Table 3-27.
3-59
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Table 3-25. DEVICE 468 EMISSION TEST RESULTS WITHOUT
AIR INJECTION (REFERENCE 2)
Table 3-26. DEVICE 468 EMISSION TEST RESULTS WITH
AIR INJECTION (REFERENCE 2)
i
ON
O
Vehicle Description
1971 Plymouth Fury III
360 CID Engine
Automatic Transmission
Power Steering
Power Brakes
Air Conditioning
Modifications
3- Venturi Carburetor
EGR System
Exhaust Manifold Reactor
Exhaust Port Liners
Evaporative Loss Controls
Exhaust Cooler Units
1972 CVS Procedure (Single-bag tests)
Run Date
2-26-71
3-2-71
3-8-71
3-24-71
4-8-71
Avg.
HC
gm/mi
1.00
0.74
0.92
0.82
1.00
0.89
CO
gm/mi
8.0
7.3
7.6
10.0
10.0
8.6
NO
gm/mi
1.6
1.7
0.86
1.5
1.23
1.37
1975 CVS Procedure (Three -bag tests)
0.52
6.2
1.37
Vehicle Description
1970 Pontiac LeMans
400 CID Engine
Automatic Transmission
Power Steering
Power Brakes
Modifications
3-Venturi Carburetor
EGR System
Exhaust Manifold Reactor
Exhaust Port Liners
Evaporative Loss Controls
Exhaust Cooler Units
Particulate Trapping Device
Air-Injection Pump (Operates During
Choking Period)
Transmission Modifications
(Modulator and Governor)
1972 CVS Procedure
Run Date i
4-5-71
4-6-71
4-19-71
4-20-71
4-21-71
4-22-71
6-3-71
6-24-71
Avg.
12-18-70
1970 7-Mode Procedure
Run Date
4-8-71
4-13-71
4-14-71
Avg.
Equivalent gm/mi
HC CO
gm/mi) (em /mi) j
0.74 7.3
0.75 7.0
0.74 5.3
0.78 6.2 .
0. 84 6. 2
0. 82 5. 9
0. 88 6. 5
0.73 6.8
0.79 6.4
0. 64 9. 1
HC CO
(ppm) (%)
19 0.21
20 0.20
23 0.21
20.7 0.21
0.26 5.0
NO
X
gm/mi)
1.40
1.60
1.70
1.70
1.48
1.45
1.45
1.40
1.52
1.09
NO
(ppm)
226
200
197
208
0. 81
-------
Table 3-27. DEVICE 468 LTR-EGR DURABILITY EMISSION TEST RESULTS
(REFERENCE 2) (1)
DATE
11-19-70
1-26-71
4-1-71
5-18-71
APPROXIMATE
MILES
0
3,000
6,000
8,000
POLLUTANTS (GM/MI)
HC
0.60
0.47
0.51
0.42
CO
8.34
7.87
8.11
8.8
NOx
0.72
0.48
0.77
0.79
(1) 1970 equivalent mass method measurements by the California
Air Resources Board.
The LTR-EGR tests performed by the developer have been with fully leaded fuels and
no adverse effects have been observed on the thermal reactor. The developer has in-
dicated that deposits in the EGR system can be expected to result from the decomposi-
tion of fuel and lubricant additives, from tars and carbonaceous matter produced
during combustion, and from ferrous oxides from exhaust system parts. In addition,
water condensate could be an important factor in promoting deposits. The developer
has found that self-cleaning EGR orifice designs (plungers, specially coated sur-
faces, or flexible snap-rings) in areas of likely deposit buildup are practical for
preventing deposit plugging and loss of EGR effectiveness. The more advanced modu-
lating EGR system now used on lean reactor cars was found to be free of such deposits
after 12,000 miles of service on the car tested by the California Air Resources
Board. This EGR system was tested successfully for 30,000 equivalent miles on the
dynamometer (Reference 2).
Materials testing data on leaded fuels indicate that corrosion effects due to lead
halides and/or phosphate compounds in the exhaust are temperature related. Figure
3-15 indicates that, at temperatures approaching 1,700°F, corrosive weight loss rates
are not sensitive to fuel composition. This provides a rational basis for the
developer's claim that the lead composition of fuel has no impact on the Device
468 LTR. The developer has found that 430 stainless steel (with zero nickel
content) has a useful service life in the lean reactor of about 30,000 miles. The
same material had a life of only 17 hours when tested on the dynamometer at 100-mph
vehicle speed with retarded spark to increase exhaust temperature. Under the same
dynamometer conditions, a duplicate reactor fabricated of 310 stainless steel (20
percent nickel) showed no deterioration for more than 200 hours (equivalent to
20,000 miles). Therefore, the developer has concluded that 310 stainless steel
should provide a tenfold improvement over.the 30,.000-mile road service obtained with
stainless steel.
3.2.3.5 Maintainability
With the requirement for an air pump eliminated, Device 468 should require no peri-
odic servicing other than that associated with the EGR subsystem and normal vehicle
maintenance. Carburetor idle adjustment could be performed during regular engine tuneup
and therefore would not be a special requirement of the device. The EGR subsystem
would require about 40 minutes of service every 12,000 miles.
3-61
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3.2.3.6 Driveability and Safety
The developer has reported (Reference 2) that acceptable driveability is achieved
with the lean air-fuel mixtures required for LTR-EGR operation, because it is pos-
sible to operate the engine at a high-compression ratio. Since this enables tetra*-
ethyl lead (TEL) fuel to be used with the LTR-EGR, it does not apprently have the
fuel economy penalties that would otherwise result from lowering the compression
ratio to use low-octane fuels.
The developer has reported fuel economy test results for the aforementioned Plymouth
and Pontiac LTR-EGR cars (Tables 3-25 and 3-26). Two test routes were used to mea-
sure fuel economy under consumer driving conditions, with characteristics as follows:
a. City and Expressway Route; a 27.7-mile loop, 10 stops per loop, with aver-
age speed of 36.7 mph.
b. City Route: an 18.4-mile loop, 40 stops per loop, with average speed of
23.4 mph.
Table 3-28 shows the results obtained on these test routes with the lean reactor
cars and their unmodified production counterparts. The economy losses apparently
occurred because of the substantial amounts of EGR used. Earlier versions of lean
reactor cars without EGR indicated little or no loss in fuel economy in comparison
with the corresponding unmodified car.
3.2.3.7 Installation Description
The specific installation requirements for this device could not be defined,
because the system data obtained were incomplete with respect to the detailed
system description.
3.2.3.8 Initial and Recurring Costs
These costs could not be estimated for the same reason stated in paragraph 3.2.3.7.
Because it would apparently incorporate low cost materials, would not require an
air pump, and may not have exorbitant fuel economy penalties, Device 468 possibly
would be considerably less expensive than an RTR approach to exhaust emission
control.
There are no apparent safety problems indicated by the technical characteristics of
this device.
3.2.3.9 Feasibility Summary
The effective emission reduction capability indicated by Device 468, combined with
its possibly acceptable initial and recurring costs, suggest that it should be con-
sidered for further test and analysis as a candidate retrofit method.
3-62
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Table 3-28. DEVICE 468 LTR-EGR FUEL CONSUMPTION COMPARED TO
CONVENTIONAL CARS (REFERENCE 2)
Item
Average Speed
Stops per Mile
1971 Plymouth Fury IU, 360 CID
Standard Car
Modified Car
Car A
Car B
Economy Loss
Avg
1970 Pontiac LeMans. 400 CID
Standard Car
Modified Car
Economy Loss
Avg.
City Route
23 mph
2. 17
11.1 mpg
11.0 mpg
11.1 mpg
0.5%
6.6%
11.5 mpg
10. 6 mpg
7.8%
8.6%
City and
Expressway
36 mph
0.36
16. 7 mpg
14. 5 mpg
14. 7 mpg
12.6%
14. 9 mpg
13. 5 mpg
9.4%
3-63
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3.2.4 Device 31; Thermal Reaction by Turbine Blower Air Injection
Device 31 is a turbine driven air pump designed to replace the conventional air in-
jection pumps used to supply air to exhaust manifolds, thermal reactors, and cata-
lytic converters for the oxidation of CO and HC. The device incorporates a variable
displacement, centrifugal pump driven by a small (3-inch-diameter) impulse turbine.
Impulse turbine power is derived from air drawn through the turbine by intake mani-
fold vacuum.
This appears to be a well developed device. The developer has conducted sufficient
tests to demonstrate that the turbine driven air pump, when used with an exhaust
manifold air injection system, for control of HC and CO exhaust emissions, performs
as well as conventional air pumps.
The device was evaluated solely on the basis of developer provided data. No com-
parison of relative costs was provided by the developer.
3.2.4.1 Physical Description
As shown in Figure 3-22, the device has a turbine section (right side) and centri-
fugal pump section (left side) contained in an integral assembly. The 3-inch-
diameter turbine wheel and centrifugal impeller are rigidly mounted on a common
shaft supported in between by a single duplexed pair of miniature ball bearings.
The entire turbine/blower assembly weighs approximately 1.75 pounds.
Figure 3-22. DEVICE 31 TURBINE BLOWER CONFIGURATION (DEVELOPER PHOTO)
3-64
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3.2.4.2 Functional Description
Figure 3-23 shows a typical installation of Device 31. Three ports are provided in
the pump housing: (1) an air inlet entering axially from the right, (2) a vacuum
outlet, and (3) a blower air outlet discharging tangentially in line with the im<-
peller. Inlet air to the blower and turbine is first passed through an air filter.
Turbine air is drawn from the air inlet immediately upstream of the impeller and
ported along axial passages in the housing wall to an annular plenum chamber.
From the plenum chamber air is drawn through a tangentially oriented, tubular
nozzle to impinge on turbine buckets. The blower discharge is equipped with a
check valve which is essential to blower performance as well as a safety device to
prevent exhaust backflow if backfiring should occur.
DEVICE 31
AIR PUMP
Figure 3-23. DEVICE 31 AIR INJECTION SYSTEM CONFIGURATION
(DEVELOPER SKETCH)
Figure 3-24 shows the air pumping characteristics of the device with the engine
operating at a constant 1,800 rpm, while intake manifold vacuum was varied. This
figure indicates that blower output varied almost directly with intake manifold
vacuum. A maximum blower output of about 10 cubic feet per minute was achieved at
24 inches of mercury intake manifold vacuum. Blower output ceased at about 6 inches
of mercury intake manifold vacuum even though at approximately 15 inches of mercury
intake manifold vacuum, blower outlet pressure equaled exhaust manifold pressure.
Blower output flow at the latter vacuum was about 5 cfm and did not become zero un-
til exhaust pressure was over five times blower output pressure. This is explained
3-65
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fl.L
PERFORMANCE CHARACTERISTICS
283 CID V-81800 RPM
EXHAUST \
MANIFOLD
PRESSURE
/BLOWER
/ OUTPUT
FLOW
40
46 12 16 20 24
INTAKE MANIFOLD VACUUM
INCHES OF HERCMY
Figure 3-24. DEVICE 31 TURBINE BLOWER AIR PUMPING CHARACTERISTICS
(DEVELOPER DATA)
by the developer as a combination of pressure variations in the exhaust and the action
of check valves in the device. The exhaust pressure undergoes high and low fluctua-
tions. The check valves permit blower output air to enter the exhaust during exhaust
pressure fluctuations in which the exhaust pressure is lower than that of the pump.
Figure 3-25 shows the air pumping capability of the turbine blower, expressed as
percent of engine inlet air (carburetor air plus turbine air).
100
60
40
20
PERFORMANCE CKAKACTISISTICS
SLOWER OUTPUT FLOW AS
PERCENT OF ENGINE INL'T AIR FLOW
283 CIO V-8 - ROAD LOAD
20
30
SPEED
MPH
40
SO
60
Figure 3-25. DEVICE 31 TURBINE BLOWER OUTPUT AS PERCENT OF ENGINE
INLET AIRFLOW (DEVELOPER DATA)
3-66
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3.2.4.3 Performance Characteristics
The emission control performance capability of air injection systems using the tur-
bine blower was evaluated by the developer by comparing the results of cold start
dynamometer tests on air injection system equipped cars, first with the turbine
blower supplying the air, then with the standard pump supplying the air. The
procedure consisted in performing hot cycles with the vehicles in the as-received
condition, both with and without air. From the without-air tests idle CO and
speed were noted. The turbine blower vacuum line was then connected to the intake
manifold and the idle CO and speed set to their original values to compensate for
the introduction of turbine air into the intake manifold.
Cold start emission tests were performed, first with the turbine blower supplying
air and the standard pump discharging to atmosphere, and then with the standard
pump supplying the air and the turbine-blower discharging to atmosphere. Six air-
injection-equipped 1966 and 1967 model automobiles, with engine displacements rang-
ing from 164 cubic inches to 428 cubic inches, were tested in this manner. Three of
the cars had six-cylinder engines and one had a manual transmission. Odometer read-
ings varied between a few miles and 15,000 miles.
Results of the evaluation tests showed nearly identical emission control with
either the standard pump or the turbine blower supplying the air. Emission test
results were as shown in Table 3-29.
The average HC and CO emission test results from six vehicles during the course of
a 7-mode, 7-cycle comparison test are plotted in Figure 3-26. The vehicles were
equipped with an exhaust manifold air injection system. Emission trends are shown
for air injection systems equipped with both turbine blower and conventional air
pump. No significant differences in emissions result from substitution of the tur-
bine air pump.
Table 3-29. DEVICE 31 TURBINE BLOWER AND CONVENTIONAL AIR PUMP SYSTEM
EMISSION TEST RESULTS (DEVELOPER 7-MODE DATA)
TEST CONDITION
Warmup Cycles
1-4
Hot Cycles
6 and 7
Weighted
Average (1)
STANDARD PUMP SYSTEM
HC (ppm)
297
237
258
CO (%)
1.33
0.92
1.06
TURBINE BLOWER SYSTEM
HC (ppm)
300
236
258
CO (%)
1.51
0.91
1.12
(1) Average of six cars.
3-67
-------
500
400
300
HC
PPM
200
100
COMPOSITE RESULTS
PUMP
STANDARD
DEVICE 31
HC
258
258
• HC DEVICE 31 SYSTEM
CO
1.86
1.12
CO DEVICE 31 SYSTEM
CO
345
CALIFORNIA TEST CYCLE
Figure 3-26. DEVICE 31 TURBINE BLOWER EMISSION TEST COMPARISON
WITH CONVENTIONAL AIR PUMP SYSTEM (DEVELOPER DATA)
3.2.4.4 Reliability
The device is an air driven turbine as compared to the belt driven pump it replaces.
Provided appropriate bearings have been selected, and their lubrication system pro-
perly designed, the reliability of the device should exceed that for belt driven
pumps because the device bearings are symmetrically loaded as opposed to the radial
loading for a standard belt type pump. Assuming such consideration has been given
the bearing and lubrication system, it is estimated that the device reliability
(MMBTF) would exceed 50,000 miles.
3.2.4.5 Maintainability
The only anticipated routine maintenance is changing or cleaning of the air filter
every 12,000 miles, plus an inspection of hoses and turbine blower attachments to
the engine. Changing or cleaning the filter could be accomplished within 15 minutes
provided the device is readily accessible. The bearings might require lubrication
if not designed for a minimum of 50,000 miles without maintenance. The developer
noted that there is no requirement for lubrication, because the pump contains a
sealed bearing system. Overall maintenance and corrective action at 12,000-mile
intervals should not exceed 0.5 hour.
3.2.4.6 Driveability and Safety
No safety hazards were identified. However, engineering estimates based on the
developer's data indicate that rotational velocities could exceed 20,000 revolu-
tions per minute. Therefore, a critical design review should be performed prior
to full-scale production to assure that there is no safety hazard resulting from
explosive disintegration of the turbine or impeller.
3-68
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This device was not tested for driveability and the developer supplied no drive-
ability data. Therefore, no evaluation could be made as to the effects of this
device on vehicle driveability.
3.2.4.7 Installation Description
The Device 31 installation on cars not already equipped with an air injection
system consists in drilling holes in the engine exhaust manifold so that air may
be injected into the exhaust system immediately adjacent to the exhaust valves,
installing air injection nozzles and manifold, installing a turbine blower to pro-
vide air for injection, and drilling a hole in the intake manifold to provide air
flow for the turbine section of the blower. On later model-year vehicles with a
conventional air pump, the existing pump would be replaced with a Device 31 turbine
blower.
Table 3-30 lists the installation requirements. Installation could be accomplished
by a skilled mechanic in a normally equipped repair shop. Figure 3-27 shows a typi-
cal installation for a 6-cylinder engine.
3.2.4.8 Initial and Recurring Costs
Table 3-31 summarizes the costs for this device. From the information available, it
is estimated that the cost for installing this device, including material, would be
approximately $142.50 for a complete air injection system.
Recurring costs would be insignificant, based on the assumption that the only mainte-
nance required would be the cleaning of the air filter.
3.2.4.9 Feasibility Summary
This device is considered technically feasible as an air source for exhaust air
injection systems. The device appears to be well engineered and designed; however,
no information regarding durability is available. It is questionable if this device
is feasible for retrofit application because of the relatively high installation
costs for an unequipped vehicle.
3-69
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Table 3-30. DEVICE 31 TURBINE BLOWER AIR INJECTION SYSTEM INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Drill and tap holes in engine exhaust
manifold adjacent to exhaust valves.
2. Secure air injection nozzles into
holes in exhaust manifold.
3. Connect injection manifold to air in-
jection nozzles
4. Attach mounting bracket to engine
5. Attach turbine blower to mounting
bracket
6. Attach 3/4" hose from the blower out-
put to the air injection manifold
through check valves
7. Drill and tap hole in intake manifold
near base of carburetor
8. Secure connector in hole in intake
manifold
9. Attach hose from turbine outlet to
intake manifold
LO. Reassemble engine accessories
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Electric drill
c. Tap
a. Hand tools
b. Air injection nozzles
a. Hand tools
b. Air injection manifold
a. Hand tools
b. Mounting bracket
a. Hand tools
b. Turbine blower
a. Hand tools
b. Hose clamps
c. Hose
d. Check valves
a. Electric drill
b. Tap
a. Hand tools
b. Connector
a. Hand tools
b. Hose
c. Hose clamps
Hand tools
Total Time
TIME
(MEN,)
120
45
30
10
10
10
15
5
10
45
5.0 hrs
3-70
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Figure 3-27. DEVICE 31 TURBINE BLOWER AIR INJECTION SYSTEM INSTALLATION
(DEVELOPER PHOTO)
3-71
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Table 3-31. DEVICE 31 TURBINE BLOWER AIR INJECTION SYSTEM
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Air injection
nozzles and
manifold
b. Turbine blower
c. Check valves
a. Mounting bracket
b. Hose and hose
clamps
c. Connector
j Table 3-30
Total Initial Cost
50,000-Mile Recurring
Cost:
Material
Labor
1. Air filter and
turbine
installation
(None assumed to be re
Cleaning and
inspection
LABOR HOURS OR
ITEM QUANTITY
5 hrs
quired)
1/2 hr every
12,000 miles
@$12.50 per
hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
80.00
(Included in
above)
62.50
142.50
25.00
25.00
167.50
3-72
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3.3 EXHAUST GAS AFTERBURNER - RETROFIT SUBTYPE 1.1.3
The afterburner approach to exhaust gas control is based on the same principle
of operation as the thermal reactor: CO and HC are oxidized to carbon dioxide
and water under a sustained combustion temperature environment. With the after-
burner, however, this process occurs downstream of the exhaust manifold rather
than in the manifold. Whereas the thermal reactor takes advantage of the hot
exhaust gas to sustain the necessary temperature for oxidation, the afterburner
requires an auxiliary ignition system, since the exhaust gas has cooled below
the oxidation point by the time the gas reaches the afterburner.
To achieve combustion in the afterburner, the air-fuel ratio may have to be low-
ered so that more fuel is present in the exhaust gas. This is the same approach
used in a rich exhaust gas reactor, as described in paragraph 3.2.1, to increase
reaction temperature. If lower air-fuel ratio is used, then NOx emissions con-
currently decrease because of the lower availability of oxygen and cooler engine-
cylinder combustion temperature of a rich fuel mixture. With rich fuel mixture,
some form of air injection is required, so that sufficient air is present to sup-
port combustion of the mixture in the afterburner.
Two afterburner devices were evaluated, Devices 308 and 425. The developers in
both cases responded to the retrofit data survey questionnaire (refer to Volume
V, Appendix 3). Device 308 operates without requiring any change in the air-fuel
ratio, whereas Device 425 requires a rich fuel mixture.
3.3.1 Device 308; Exhaust Gas Afterburner
A single prototype unit of this device has been fabricated by the developer and
installed on 1966 and 1967 Chevrolets. The developer provided the results of
several emission tests conducted at idle, 30 mph, and 50 mph by the Arizona De-
partment of Health, Division of Air Pollution Control. The emission reduction
effectiveness was determined by testing with and without the afterburner ignition
functioning.
3.3.1.1 Physical Description
The prototype unit is shown in Figure 3-28. The afterburner chamber consists of
a 4.5-inch-diameter cylindrical steel section, 4.75 inches long. The cylinder
is closed at each end by caps with exhaust pipe inlet and discharge holes.
A spark plug and grounding electrode are sidewall mounted opposite each other, so
that they project radially inward to provide a spark gap of approximately 0.5
inch between the electrodes on the chamber centerline, approximately 1 inch downstream
of the exhaust inlet. A circular plate, ringed with holes, is located transversely
in the chamber, downstream of the spark system.
The spark plug is connected through a high voltage wire to a coil that, in turn,
is connected to one side of a dual-point distributor plate and condensers incor-
porated in the standard engine distributor in place of the standard single-point
distributor plate.
3-73
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BB054
Figure 3-28.
DEVICE 308 EXHAUST GAS AFTERBURNER SHOWING SPARK PLUG (RIGHT SIDE)
AND DIAMETRICALLY OPPOSED ELECTRODE (LEFT SIDE)
3.3.1.2 Functional Description
Device 308 provides a chamber or accumulator through which exhaust gas flow is
restricted while being subjected to a continuous ignition spark stimulus under
all engine operating conditions. One set of the dual points and their condenser
controls the coil of the standard engine ignition system, and the second set con-
trols the coil of the afterburner ignition system. The objective of the continu-
ous spark is to expose the center of the exhaust gas stream to high temperature,
with the intent of oxidizing unburned CO and HC to carbon dioxide and water.
Since the afterburner spark plug operates off the engine distributor, a high
voltage spark is directed across the exhaust gas entering the afterburner, when-
ever the engine is operating. The developer specifies that the engine be tuned
to the vehicle manufacturer's specifications, with no emphasis on lean or rich
carburetion (refer to Volume V, Appendix 3, Device 308 questionnaire response).
3.3.1.3 Performance Characteristics
Exhaust emission test results were reported by the developer, based on tests of a
1967 Chevrolet with and without the afterburner operating. The results are sum-
marized in Table 3-32.
3-74
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Table 3-32. DEVICE 308 EXHAUST GAS AFTERBURNER EMISSION TEST
RESULTS REPORTED BY DEVELOPER (REFERENCE 18) (1)
TEST
CONDITION (2)
Idle
Without Device
With Device
Percent Reduction
30 MPH
Without Device
With Device
Percent Reduction
50 MPH
Without Device
With Device
Percent Reduction
POLLUTANT
HC(PPM)
150
200
-33
160
150
7
120
150
-25
CO (PERCENT)
2.8
2.5
10
1.4
1.5
-7
0.9
1.1
-22
NOx(PPM)
150
150
0
300
250
17
500
450
10
(1) Results obtained by Arizona State Department of Health,
Division of Air Pollution Control, under steady state
engine rpm noted, with and without device operating on
a 1967 Chevrolet sedan with a 327-cubic-inch-displace-
ment engine and automatic transmission.
(2) . One set of tests, each condition.
These results show no significant reduction of emissions. The device appears to
perform more as an NOx control than as a CO and HC control. This may be attrib-
utable to exhaust backpressure caused by the transverse plate in the afterburner
chamber; this backpressure may induce some exhaust gas recirculation, which
would have the effect of lowering combustion temperature and inhibiting the
formation of NOx. This concept of device operation assumes that the device was
not installed in the exhaust system of the test vehicle when the "without device"
emission data were obtained.
3.3.1.4 Reliability
The device uses a standard automotive ignition coil, one half of a standard set
of dual ignition points (the other half is used for engine ignition), and a
single-electrode spark plug. Mean-miles-before-total-failure would exceed 50,000
miles provided the points and spark plug are replaced or maintained in accordance
with the manufacturer's recommendations.
3-75
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3.3.1.5 Maintainability
The ignition points utilized by the device, associated capacitor, and the spark
plug will require the same maintenance as the points, capacitor, and spark plugs
used for engine ignition. The afterburner high voltage line might require more
frequent replacement than the engine ignition wires, depending on physical loca-
tion, because of increased exposure to road hazards and exposure to exhaust pipe
heat. The following preventive maintenance requirements are assumed to be re-
quired at the mileages noted, to achieve the reliability potential of the device:
a. Inspect spark plug gap every 12,000 miles and adjust electrode
as required.
b. Replace breaker points every 12,000 miles (1).
c. Inspect spark plug lead every 12,000 miles.
d. Inspect afterburner chamber every 12,000 miles.
3.3.1.6 Driveability and Safety
Driveability data provided by the developer (Volume V, Appendix V-3) indicate that
the device has no adverse effect on the vehicle's general driving quality. No
information was provided as to the effect of the device on vehicle acceleration,
deceleration, or gas mileage. No special type of fuel is required.
There are no apparent safety hazards for the vehicle operator or for the vehicle.
3.3.1.7 Installation Description
The installation of this device consists in cutting out a 5-inch section of
exhaust line, inserting the afterburner into the exhaust line, replacing the
standard single-set distributor points with a set of dual points, installing
a second ignition coil, and electrically hooking up the points, coil, and after-
burner. The developer specifies that the device should be installed as close to
the exhaust manifold as possible. Adjustment consists in tuning the engine to
the automobile manufacturer's specifications.
The developer estimates that installation of the complete system should take
about one hour. Table 3-33 itemizes the installation procedure and identifies
the tools and special equipment required. Installation can be accomplished in
a normally equipped automobile repair shop by the average mechanic.
(1) Based on information obtained from automotive repair personnel at Olson
Laboratories, points should be replaced for the average vehicle at approx-
imately 12,000 miles. The only maintenance cost attributable to the device
would be the cost of the breaker point set used by the device (approx-
imately $3.00).
3-76
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Table 3-33. DEVICE 308 EXHAUST GAS AFTERBURNER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Cut exhaust line between exhaust
manifold and muffler and remove
approximately 5-inches of exhaust
line.
2. Install afterburner in exhaust line
and secure with clamps.
3. Remove ignition distributor points
and replace with a set of dual points
4. Install another coil in the engine
compartment.
5. Connect wires from extra set of dis-
tributor points to extra coil to
afterburner.
6. Tuneup engine.
TOOLS, EQUIPMENT
AND FACILITIES
Oxyacetylene torch
a. Hand tools
b. Afterburner
c. Clamps
a. Hand tools
b. Dual ignition
c. Distributor points
a. Ignition coil
b. Electric drill
c. Clamp
d. Sheet metal screws
a. Hand tools
b. Wire
Engine analyzer
TIME
(MEN.)
10
20
9
15
6
15
Total Time 1.15 hr
3.3.1.8 Initial and Recurring Costs
The developer estimates that the device would cost $35. Table 3-34 summarizes
the installation costs for this device. From the information available, it is
estimated that the cost for installing this device, including material, would be
$70.62.
3.3.1.9 Feasibility Summary.
The test and design information provided by the developer indicate that this
device is not technically feasible with respect to emission reduction effective-
ness. The emission data provided indicate that the device does not implement the
exhaust afterburner principles of operation with respect to CO and HC oxidation.
No significant exhaust pollutant decrease is indicated in the data supplied by
the developer.
3-77
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Table 3-34. DEVICE 308 EXHAUST GAS AFTERBURNER INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and ad-
just
DESCRIPTION
Afterburner (with
spark plug)
a. Clamps
b. Dual ignition
points
c. Ignition coil
d. Sheet metal screws
e. Electric wire
Table 3-33
Table 3-33
LABOR HOURS OR
ITEM QUANTITY
1.00 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Labor
1. Inspections
2. Install
Material
1. Breaker points
a. Spark plug gap and
ignition lead
b. Afterburner chamber
c. Break points
One-half of a dual
set
0.5 hr/12,000 miles
0.3 hr/12,000 miles
$2.50/12,000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
35.00
20.00
12.50
3.12
70.62
25.00
15.00
10.00
50.00
120.62
3-78
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3.3.2 Device 425; Exhaust Gas Afterburner
Device 425 represents a system approach to the afterburner concept for controlling
vehicle exhaust emissions. The afterburner creates and sustains a thermal reac-
tion environment for the oxidation of CO and HC to carbon dioxide and water, by
combustion within the chamber. Lower air-fuel ratio is required to support the
combustion process in the afterburner and this richer air-fuel mixture inhibits
NOx formation during the engine combustion cycle.
This system has been under development since 1968. Five prototype models have
been developed, and one of these models (covered by U.S. Patent No. 3,601,982)
has been selected for production (refer to developer's data survey questionnaire
response, Volume V, Appendix V-3).
3.3.2.1 Physical Description
Device 425 consists of a combination acoustic muffler and afterburner, an air
pump, and an electronic controller to meter air flow and ignite the afterburner.
Figure 3-29 shows a cross-sectional view of the afterburner unit. The after-
burner unit is 6 inches in diameter and 24 inches long. It incorporates a special
spark plug to initiate the combustion process. It is installed in place of the
muffler. Because of the heat generated, the unit is heavily insulated, and a
finned tailpipe is used. The air pump is of the same type now utilized to inject
air into the exhaust manifold on many late model cars. A special carburetor may
be required to obtain the desired low air-fuel ratio.
3.3.2.2 Functional Description
Device 425 operates on the principle of burning excess HC and CO in the exhaust
gas after it is exhausted from the engine. Nitrogen oxides are controlled by
utilizing a rich air-to-fuel mixture. The following description of the device
was provided by the developer:
". . . The device is designed as concentric inner and
outer housings of a combined acoustical muffler and
afterburner. A wire, filling the approximate one-eighth
of an inch of space between the inner and outer housings
is spiraled around the inner housing to lengthen the
passageway for incoming fresh air so as to maximize
the heat transfer between the hot combuster wall and
the incoming fresh air. Fresh air enters the rear
end of the device and is forced around and between the
inner and outer housings. At the front end of the
device the fresh air is mixed with the exhaust of the
engine consisting of carbon monoxide, hydrocarbons and
nitrous oxides. This mixture which is at an initial
temperature of about 400 degrees Fahrenheit, then enters
tubings which carry the mixture to the rear of the unit.
At this point the mixture is ignited and quickly reaches
a combustion temperature of about 1,350 degrees Fahren-
heit. The now burning mixture returns to the front end
of the unit and then is channeled to the outer edge of
3-79
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Note: Numbers refer to
patent disclosure text
Figure 3-29. DEVICE 425 EXHAUST GAS AFTERBURNER
(U.S. PATENT NO. 3,601,982)
the tube bank where it is transversed to the exhaust end
of the unit. Thus, the mixture of chemicals and fresh
air are burning during three passes from the entrance of
the exhaust manifold to the exhaust end of the unit.
Burning is attained by creating a stoichiometric mixture
of chemicals and fresh air. A small, inexpensive elec-
tronic controller adjusts the amount of fresh air so
that the right amount is introduced based on the RPM of
the engine which creates a finite volume of exhaust.
The fresh air, as stated, enters the unit at the rear
and while transversing the spiraled wall, tends to cool
the outer housing and is pre-heated to avoid a quenching
effect when the fresh air is mixed with the exhaust.
In order for thermal reactors to burn 100% of the burn-
able pollutants, enough pollutants must be available to
quickly catch on fire and maintain a burnable temper-
ature. Six percent or more of carbon monoxide will burn
in a chain reaction. Less than six percent must have
enough heat to burn each individual module. This effect-
iveness cannot be attained with the lean carburetors now
3-80
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being installed on vehicles. An air/fuel ratio of approx-
imately 11.5/1 is desired. However, this rich mixture
tends to greatly reduce the creation of nitrous oxides
which are more toxic to the human body than is carbon
monoxide. Nitrous oxides cannot be removed by burning. . ."
3.3.2.3 Performance Characteristics
Table 3-35 presents the emission test results reported by the developer for
Device 425. In tests performed by the Ethyl Corporation (Reference 19) with
the device installed on the same vehicle; average emissions of 16.5 ppm HC,
0.24. percent CO, and 131 ppm NOx were obtained for four hot cycles under the
1968 Federal Test Procedure (Reference 14).
Table 3-35. DEVICE 425 EXHAUST GAS AFTERBURNER EMISSION TEST RESULTS
REPORTED BY DEVELOPER (1)
TEST
CONDITION
Without Device
With Device
Percent Reduction
POLLUTANT
HC(PPM)
500.29
17.18
97
CO (PERCENT)
9.37
0.26
97
(1) Results reported by developer for one cycle
of the 1968 Federal Test Procedure with and
without the device installed on a 1969 Chev-
rolet 6-cylinder, manual transmission vehi-
cle equipped with a General Motors certified
air pump and a special Rochester carburetor
with 11.5:1 air-fuel ratio (refer to Device
425 data questionnaire response, Volume V,
Appendix 3). Tests performed by a depart-
ment store Diagnostic Center, Seven Corners,
Virginia.
3.3.2.4 Reliability
Device 425 should meet a 50,000-mile MMBTF life standard, provided that the
production design incorporates suitable components and materials, and that the
device is maintained satisfactorily throughout its service life. The system
components affecting the reliability of Device 425 consist of the air-injection
pump, the electronic control unit, and the combustion chamber with spark plug
ignition device. The developer noted that the air pump could be the standard
3-81
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automotive belt-driven pump now used on many vehicles. Assuming proper mainte-
nance, including that pertaining to filtration of input air, pump reliability
should exceed 50,000 mean-miles-before-total-failure. This estimate is applicable
to pumps having rotary blowers with graphite sealing vanes and sealed bearings.
The developer did not define the electronic control unit (ECU) sufficiently for
reliability evaluation; however, it can be deduced that it performs at least the
following functions:
a. Provides a high voltage pulse to the spark plug ignition device. (1)
b. Provides airflow volume control.
c. Provides an indication to the motorist that the system is or is
not func t ioning.
It is anticipated that an ECU which can provide the required functions can be
developed and manufactured with a reliability in excess of 50,000 mean miles
before failure.
The specific type of special spark plug which would be used was not identified;
it is assumed that it would be replaced during routine vehicle maintenance to
preclude failure so as not to jeopardize the 50,000-mile system service life. In
the recurring cost estimation of Table 3-37, it was assumed the spark plug would
be replaced once at 25,000 miles.
Operating in a temperature range of 1,350-1,500F, with low air-fuel ratio, Device
425 is analogous to a rich thermal reactor. Therefore, the corrosive effects of
high temperature and rich fuel mixture may be a consideration in the material
composition of the device. As discussed in paragraph 3.2.1, test data obtained so
far on the effect of fuel and temperature on reactor materials indicate that leaded
fuels have a significant corrosive effect on reactor metals at temperatures over
1,700°F. Since Device 425 is reported by the developer to operate in the 1,350°-
1,500°F range, corrosion due to leaded fuel should not be a problem if suitable
materials are used in the construction of the device.
With regard to the material composition of the afterburner, the developer stated:
"The Thermal Reactor operates at very high internal temp-
eratures. Accordingly, it must be constructed out of
metals which will not be affected by the internal heat.
In addition, the metals should not be affected by lead
deposits or other chemical reaction. A special steel
was selected which the manufacturer guarantees will
withstand up to 3,000°F for a minimum of 3,000 hours of
operation."
(1) The ECU should either provide continuous spark pulses or provide for auto-
matic restart after flameout. The safety implications of this are discussed
in paragraph 3.3.2.6.
3-82
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3.3.2.5 Maintainability
According to the developer, the only item which would normally require servicing
is the special spark plug which is used to initially light off the exhaust gas.
The developer estimated that the spark plug will retail for about $2.00. It is
assumed it would be inspected at 12,000-mile intervals and replaced at 25,000
miles.
Three other maintenance requirements are assumed:
a. Maintenance of the air pump filter in accordance with the manu-
facturer's requirements (assumed to be every 12,000 miles).
b. Calibration inspection of the thermocouple temperature sensor at
25,000 miles. It is assumed that the afterburner could be designed
to facilitate such maintenance.
c. Calibration inspection of the ECU at 25,000 miles.
3.3.2.6 Driveability and Safety
Device 425 was not tested as part of the retrofit study program; however, the
developer reported that the number of hours the device has been tested exceeds
50,000 miles, and that there have been no troubles in operating a vehicle with
the device installed under all weather and road conditions in which a vehicle
might normally be operated. On several long road tests the test vehicle used
10-15 percent more fuel when equipped with the special 11.5:1 air-fuel ratio car-
buretor used with the device. This increase in fuel consumption would affect
recurring costs as discussed in paragraph 3.3.2.8. No special type of fuel is
required.
Although insufficient design information was available for a comprehensive safety
review, three potential safety hazards appear to exist:
a. In the event of afterburner flameout and the absence of a
continuous ignition spark or automatic restart capability,
uncontrolled reignition could occur with explosive force.
b. In the event of afterburner internal failure or severe restriction
of the exhaust gas flow, substantial or complete loss of power
could occur.
c. Afterburner accidental puncture or burnthrough could result in a
vehicle fire or venting of toxic fumes.
These are considered safety hazards for which preventive measures would have to be
incorporated in the production design of the device, particularly through the ECU.
The developer notes that a warning light could be installed on the vehicle instru-
ment panel to indicate when the afterburner is malfunctioning.
3-S3
-------
As noted in Table 3-37, this increase in fuel consumption would be expected to
increase recurring costs. To offset this cost, the developer proposes to include,
as part of the retrofit kit, a special generator which would operate off of the
afterburner heat. However, even if this were feasible, it would add to the de-
vice's complication and initial cost.
3.3.2.7 Installation Description
Device 425 installation consists in replacing the presently installed muffler and
tailpipe with the afterburner unit, mounting an air pump in the engine compartment
with power takeoff from the engine, mounting the ECU in the engine compartment and
connecting a high voltage coil in the engine compartment, installing the malfunc-
tion warning system, and connecting the air hose, electrical wires, and drive belt.
Adjustment of the engine consists in setting the air-fuel ratio at 11.5:1. (1)
Table 3-36 itemizes the installation procedure and the tools and special equipment
required. Installation can be accomplished in a normally equipped automotive
repair shop by the average mechanic.
3.3.2.8 Initial and Recurring Costs
Table 3-37 summarizes the estimated initial purchase and installation costs for
this device. From the information available, it is estimated that the cost for
installing this device, including material, would be $158.74. (1) Added to this
would be recurring costs of $168.88 over 50,000 miles of operation. Approximately
80 percent of the recurring costs are attributable to increased fuel consumption.
3.3.2.9 Feasibility Summary
Device 425 indicates emission reduction effectiveness as tested by department store
diagnostic center for the control of CO and HC exhaust emissions. Although NOx
emissions with and without the device installed were not reported by the developer,
the 131-ppm NOx average reported for four 7-mode test hot cycles (refer to para-
graph 3.3.2.3) with the device installed is significant when compared to a 1967-
vehicle fleet average of approximately 1,000-ppm NOx obtained in the EPA Short-Test-
Cycle Effectiveness Study (Reference 17).
Though technically feasible, the device may be economically infeasible for retro-
fit applications to uncontrolled used cars, because of its high initial and recur-
ring costs. If applied only to vehicles already equipped with air injection, the
initial costs could be reduced by the amount of the air pump ($85). Since air injec-
tion systems may operate at air-fuel ratios of 12:1 (Reference 25), the carburetors
associated with them may be compatible for use with the device. A key question,
however, in converting an air injection system vehicle for use of Device 425 is
whether the device is significantly more effective in reducing emissions than the
air injection system.
(1) For the installation described in this report, it is assumed that use of a
replacement carburetor to provide 11.5:1 air-fuel ratio would not be required.
This assumption influences initial costs of the device, as noted in Table
3-37 and paragraph 3.3.2.9.
3-84
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Table 3-36. DEVICE 425 EXHAUST GAS AFTERBURNER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove muffler and tail pipe
2. Install afterburner
3. Attach bracket for air pump in the
engine compartment
4. Mount air pump on bracket
5. Attach drive belt from engine crank-
shaft pulley to air pump
6. Mount electronic control box in
engine compartment
7 . Connect air hose from air pump to
control box to afterburner
8. Mount high voltage coil in engine
compartment
9. Connect wires from spark plug in
afterburner to coil to control box
10.. Adjust air-fuel ratio to 11.5:1
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Car lift
a. Hand tools
b. Afterburner unit
c. Clamps
a . Hand tools
b. Bracket
a. Hand tools
b. Air pump
Drive belt
a. Hand tools
b. Electronix control box
a. Air hose
b. Clamps
a. Hand tools
b. High voltage coil
a. Hand tools
b. .Wire
Exhaust analyzer
Total Time
TIME
(MIN.)
15
15
5
5
5
8
7
8
7
15
1.50 hr
On post-1967 vehicles incorporating engine modifications for exhaust emission
control, the existing carburetor would require modification or replacement to pro-
vide the rich fuel mixture desired for device operation. Carburetors on these
vehicles typically operate in the 13.5:1 to 14.5:1 air-fuel ratio range (Reference
25). In additionto the carburetor modification or replacement associated with
device use on these cars, an air pump would be required. Device initial costs for
these cars might be in the range of $180-200.
3-85
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Table 3-37. DEVICE 425 EXHAUST GAS AFTERBURNER INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Air pump
b. Afterburner unit
c. Electronic control
d. Malfunction
warning system
a. High voltage coil
b. Air hose and
clamps
c. Clamps for exhaust
pipe
d. Drive belt
e. Wire
Table 3-36
Table 3-36
LABOR HOURS OR
ITEM QUANTITY
1.25 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material;
1. Spark plug
2. Fuel
Labor;
1. Spark plug
2. Air pump filter
3. Thermocouple
and ECU
Replace at 25,000
miles
As specified by vehi-
cle manufacturer
•
a. Inspect
b. One replacement
Clean
Inspect and
calibrate
2.00
$0.35 per gallon x
10 percent fuel in-
crease (400 gallons)
for 50,000 miles
0.1 hr/12,000 miles
x 4 inspections
0.25 hr/25,000 miles
0.25 hr/12,000 miles
x 4 inspections
0.5 hr/25,000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
125.00
15.00
15.62
3.12
$158.74 (1)
2.00
140.00
5.00
3.13
12.50
6.25
$ 168.88
$ 327.62
(1) $20-$40 more if replacement carburetor is required.
3-86
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On pre-1968 vehicles, the carburetor would generally be compatible for richer
air-fuel mixture adjustment; however, these carburetors may not be compatible
for an air-fuel ratio of 11.5:1. The developer of Device 425 found it necessary
to install a special carburetor on his 1967 Chevrolet to obtain this air-fuel
ratio.
The developer noted that the vehicle owner would be saved the cost of muffler
replacement by use of Device 425. This assumption may be valid for single-
muffler exhaust systems and, if so, could offset the cost of carburetor changes.
For dual-muffler systems, however? the cost of exhaust pipe rerouting might offset
any muffler savings.
In addition to these initial cost considerations, the device appears to have inher-
ently higher recurring costs, due to an increase in fuel consumption.
Based on the cost considerations associated with Device 425, it would appear that
its emission reduction capability as a retrofit device would be applied principally
to those emission control situations (such as those associated with high vehicle
population densities in metropolitan areas) in which cost considerations are of
second order importance to the need for emission reduction.
3-87
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3.4 EXHAUST GAS FILTER - RETROFIT SUBTYPE 1.1.4
The exhaust gas filter emission control device is designed to operate on the prin-
ciple of trapping particulate matter in the exhaust gas to prevent such matter from
being emitted into the atmosphere. The retrofit study indicated that the use of
exhaust gas filters for emission control is a relatively uncommon approach to
vehicle emission control. The Clean Air Act of 1970 set no specific limits on
vehicle particulate emissions. Particulates in gasoline-fueled motor vehicles
exhaust gas include iron, lead, and carbon compounds. Since average particle sizes
may range from 0.1 to 1.0 micron (for some lead compounds), the removal of exhaust
particles by filtering is difficult (Reference 20). As noted in Reference 20,
there is little data available on the amount and nature of particulate emission
from cars.
3.4.1 Device 164: Exhaust Gas Filter
This device, based on the information provided by the developer, appears to combine
exhaust gas filtering with acoustical resonance to remove particulates from sus-
pension in the exhaust gas. The device is in the prototype stage, with three units
having been built to date. Only limited information about the device was obtainable
from the developer, so a complete evaluation was not possible.
3.4.1.1 Physical Description
Device 164 appears to consist of a "muffler filter" and a "resonator filter" that
may be combined in sequential and/or parallel hookups, in place of the conventional
muffler system. The basic elements of the device are shown in Figure 3-30.
Figure 3-30. DEVICE 164 EXHAUST GAS FILTER COMPONENTS (DEVELOPER PHOTOGRAPH)
3-89
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3.4.1.2 Functional Description
Device 164 is intended to replace the standard exhaust muffler with a combination
muffler-filter unit and resonator.
Figure 3-31 shows a functional schematic of the device, in which two of the muffler
filter units are connected in series and parallel to a downstream resonator. Under
this arrangement, exhaust gas could flow through the No. 1 or the No. 2 muffler
but all gas going through the No. 1 muffler eventually exits through the No. 2
muffler. The mechanics of the filtering and resonating functions are not known.
RESONATOR
REAR END
NO. 2
WT 20 LB.
26" LONG
1
U- 24
L
t'
i - ;
rr s LB. .
\" LONG-H
.-• 1
->
' * *• •;
I 4
^ *
^ ^
: f- . . V/
.. r '". T
1 ^
^ ;.-R ^
i' 3,i
•26" LONG
WT 20 LB.
NO. 1
FRONT END
Figure 3-31. DEVICE 164 EXHAUST GAS FILTER FUNCTIONAL SCHEMATIC
According to test reports of the Ethyl Corporation (Reference 21), Device 164
was tested in three different configurations:
a. Two parallel exhaust pipes connected to one muffler filter
unit and a second filter unit in series.
b. A single exhaust pipe with two muffler-filter units and a
resonator in series, with two reverse bends in the piping
arrangement.
c. Three branched exhaust pipes into one muffler-filter unit, a
reverse bend pipe to a second muffler filter, and a pipe to
a third muffler-filter.
The function of these configurations was not described.
3-90
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3.4.1.3 Performance Characteristics
Table 3-38 shows the emission test results obtained by the developer with and with-
out Device 164 installed on a test vehicle.
Table 3-38. DEVICE 164 EXHAUST GAS FILTER EMISSION TEST RESULTS
REPORTED BY THE DEVELOPER (REFERENCE 21) (1)
TEST CONDITION (2)
Without Device
With Device
Percent Reduction
POLLUTANT
HC (PPM)
148.5
133.5
10.0
CO (PERCENT)
-1.31
1.28
2.0
NOx(PPM)
983.5
982.5
0.1
(1) Average exhaust emissions measured during 7-mpde, 7-cycle test of a
1970 Oldsmobile 88 with 455-cubic-inch displacement engine.
(2) One test for each condition.
It is not known what configuration of the device was tested to obtain the Table
3-38 results. In tests of the first two configurations listed in paragraph 3.4.1.2
suspended particulates were measured, using the Ethyl Black Bag Procedure, during
four hot-start 7-mode cycles. With Configuration No. 1, total suspended particu-
lates were 0.034 gm/mi. With Configuration 2, total suspended particulates were
0.028 gm/mi (Reference 21).
3.4.1.4 Reliability
Device 164 appears to have no moving parts, but to be of rigid structural construc-
tion. The developer reported that 28,000 miles have been accumulated on a vehicle
with the device installed. It would appear that the device, in a production con-
figuration, should have a service life equal to that of a standard muffler.
3.4.1.5 Maintainability
If the device traps particulate matter, some form of maintenance would be antici-
pated so as to remove the material accumulated over a period of time. It is assumed
that at least once every 25,000 miles, the muffler-filter units would be inspected
and cleaned. Assuming an average of two units per installation, about 0.5 hour
would be required to accomplish this maintenance if suitable filter access provi-
sions are designed into the device.
3-91
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3.4.1.6 Driveability and Safety
The developer reported that the driveability. characteristics of the device are nor-
mal. Backpressure tests reported by the Ethyl Corporation on Configuration No. 2
of the device indicated backpressure of 26 inches mercury at the inlet of the first
muffler-filter unit, with the car accelerating at approximately 4-inch-mercury
intake manifold vacuum in high gear at 70 mph (Reference 21). Higher exhaust back-
pressure could lower the volumetric efficiency of the engine and cause a decrease
in horsepower, with consequent increase in fuel consumption (Reference 24, Chapter
14).
3.4.1.7 Installation Description
The installation of the device consists in replacing the presently installed ex-
haust system with the muffler-filter system. No adjustments to the device or engine
are required after installation is complete. Installation of this device should
take about one hour. Table 3-39 itemizes the installation procedure and the tools
and special equipment required. Installation could be performed in a normally
equipped automotive repair or muffler shop by the average mechanic or muffler
installer.
Table 3-39. DEVICE 164 EXHAUST GAS FILTER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1.
2.
3.
4.
5.
Disconnect the exhaust line from
the exhaust manifold.
Remove and discard the presently
installed exhaust line .
Install the exhaust filtering
system.
Insure that the new system mech-
anically fits in place and does
not cause any interference.
Check exhaust system for back-
pressure leaks.
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand Tools
b. Car Lift Rack
Oxyacetylene Torch
a. Hand Tools
b. Tube Clamps
c. Exhaust Filter System
Total Time
TIME
(MIN.)
10
20
20
10
1 hr
3-92
-------
3.4.1.8 Initial and Recurring Cost
Table 3-40 summarizes the costs for this device. From the information available,
the cost of purchasing and installing this device, including material was estimated
to be $102.50. The cost of cleaning the muffler-filters at 25,000 miles is the
assumed recurring cost.
3.4.1.9 Feasibility Summary
This device is considered infeasible for use as a retrofit method for the control
of light-duty vehicle exhaust emissions of CO, HC, or NOX. For the low level of
emission reduction effectiveness indicated by the device test data, the initial
cost and the implied recurring cost would not provide a sufficient return for the
investment.
The effectiveness of the device for controlling particulate matter could not be
evaluated as part of this study, because of the lack of particulate emission data
for the vehicle without the device installed.
Table 3-40. DEVICE 164 EXHAUST GAS FILTER INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
DESCRIPTION
Exhaust Filtering
System
Welding Rod and
Muffler Brackets
Table 3-39
LABOR HOURS OR
ITEM QUANTITY
1 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Fuel
Labor
1. Inspection
Possible increase in
fuel consumption due
to high exhaust
backpressure
Inspect and Clean
muffler-filter unit
Fuel consumption data
not available
0.5 hr/25,000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
85.00
5.00
12.50
102.50
Unknown
6.25'
6.25
108.75
3-93
-------
3.5 EXHAUST GAS BACKPRESSURE CONTROL - RETROFIT SUBTYPE 1.1.5
This retrofit method category was established to cover one device which approaches
the reduction of exhaust emissions by control of the backpressure of gas in the
exhaust system. Several studj.es have been performed on the backpressure associated
with thermal reactors and catalytic converters and the consequent horsepower
required in an air pump to inject secondary air (Reference 2). Testing of Device
322 was performed by EPA to evaluate the relationship between exhaust backpressure
and emissions; and to evaluate Device 322 as a retrofit emission control for used
vehicles (Reference 22).
3.5.1 Device 322; Exhaust Gas Backpressure Valve
The developer of this device did not respond to the retrofit data survey; however,
some information was obtained from an EPA test report (Reference 22).
3.5.1.1 Physical Description
This device consists of a spring-controlled flapper valve that attaches to the end of
the exhaust pipe with the flapper hinge side up.
3.5.1.2 Functional Description
The flapper valve is normally held shut against the end of the tail pipe by pressure
of the hinge spring. When the engine is operating, the exhaust gas pressure pushes
the flapper valve open. The spring controlling the valve can be adjusted to vary
the amount of pressure the exhaust tail pipe gas has to apply to open the valve.
3.5.1.3 Performance Characteristics
Table 3-41 shows the emission test results obtained by EPA in tests of the device in-
stalled on the exhaust pipe of a 1963 Ford Galaxie.
Table 3-41. DEVICE 322 EXHAUST GAS BACKPRESSURE VALVE EMISSION TEST
RESULTS (REFERENCE 22) (1)
TEST CONDITION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
4.01
6.87
-71.3
CO
53.85
50.16
6.9
NOx
1.62
1.83
-13.0
(1) Results obtained by EPA with device installed on a 1963 Ford Galaxie
with 289-cubic-inch-displacement engine and automatic transmission,
using the 1970 Federal Test Procedure (Reference 15).
(2) One test for each condition.
3-95
-------
3.5.1.4 Feasibility Summary
Data were insufficient for a complete evaluation of Device 322 for driveability and
safety, reliability, maintainability, installation procedure, and costs. Evaluation
of these device characteristics is not considered to be justified for the present
configuration, because of its questionable emission reduction effectiveness. The
following conclusions are quoted from the Reference 22 EPA report:
"Because of the increase of unburned hydrocarbons during the
cold cycle and the lack of any meaningful reduction in both
CO and NO, it appears that Device 322 has no beneficial effect
on emissions."
The emission results obtained for Device 322 may not conclusively demonstrate that
exhaust backpressure cannot be used to decrease exhaust emissions. Correlation of
a range of backpressures with corresponding exhaust emissions should be accomplished
to establish a more complete understanding of the interaction between exhaust back-
pressure and emissions.
3-96
-------
4 - INDUCTION
CONTROL SYSTEMS
-------
SECTION 4
GROUP 1 RETROFIT METHOD DESCRIPTIONS:
TYPE 1.2 - INDUCTION CONTROL SYSTEMS
This group of retrofit methods approaches the problem of vehicle exhaust emission
control from the mixture induction side of the engine. Whereas the exhaust gas con-
trol devices described previously attempt to control the pollutant byproducts of
combustion, the induction controls try to prevent the formation of exhaust pollu-
tants. This is done in several ways: by promoting more complete fuel combustion,
by inhibiting pollutant formation, or by oxidizing the pollutants as they form in
the combustion chamber.
The oxidation process operates basically on the same principle as that for thermal
reaction downstream in the exhaust system. CO and HC are oxidized in the presence
of excess air under oxidation temperatures. The excess air for this reaction is
obtained by operating the engine on a high air-fuel ratio. The high air-fuel ratio
in effect can maintain a post-combustion reaction in the cylinder and exhaust ports
like that described previously for the thermal reactors. In some cases, exhaust
reaction temperature is augmented by retarding the ignition spark. The combination
of high air-fuel ratio and spark retard, in reducing peak combustion flame tempera-
ture, also can inhibit NOx formation, as discussed in the next section on ignition
control devices.
The inhibition of pollutant formation by induction control is directed mainly at
NOx. Exhaust gas recirculation, water injection, and valve overlap are basic induc-
tion modifications that can reduce NOx. All these methods inhibit NOx formation by
reducing the peak flame temperature of combustion.
The third approach to exhaust emission control reflected by the induction modifi-
cation retrofit group is to provide more complete vaporization and mixing of the
air-fuel mixture. The techniques used in this approach vary from carburetor rede-
sign to use of mixing devices and superchargers. The basic objective is to reduce
the pollutant byproducts of combustion by improving combustion efficiency.
Table 4-1 lists the 21 induction modification type devices studied. Of these, the
first 12, comprising Subtype 1.2.1, operate on the principle of high air-fuel ratio,
primarily to oxidize CO and HC. Subtype 1.2.2 operates on the principle of exhaust
gas recirculation, inhibiting NOx formation. The remaining subtypes approach im-
proved air-fuel vaporization and mixing through the various means indicated by the
device nomenclature.
As with the exhaust gas control group described previously, some of the induction
control systems are used in combination with vacuum advance disconnect (of the
ignition control group) to provide reduction of all three pollutants. Two combina-
tion systems use exhaust gas recirculation with vacuum advance disconnect as a
twofold approach to NOx reduction.
4-1
-------
Table 4-1. TYPE 1.2 INDUCTION CONTROL SYSTEM RETROFIT DEVICES
AIR BLEED TO INTAKE MANIFOLD - SUBTYPE 1.2.1
DEVICE NO.
KD(2)
42(2)
57
325
401
418(1)
433
458(1)
462(1)
NOMENCLATURE
Air Bleed to Intake Manifold
Air Bleed to Intake Manifold
Air Bleed with Exhaust Gas Recirculation and Vacuum Advance
Air-Vapor Bleed to Intake Manifold
Air-Vapor Bleed to Intake Manifold
Air Bleed to Intake Manifold
Air-Vapor Bleed, to Intake Manifold
Air Bleed to Intake Manifold
Air Bleed to Intake and Exhaust Manifolds
EXHAUST GAS RECIRCULATION - SUBTYPE l".2.2
10(2)
245(1)(2)
246(1X2)
294(1)
Throttle-Controlled Exhaust Gas Recirculation with Vacuum Advance
Disconnect
Variable Camshaft Timing
Speed-Controlled Exhaust Gas Recirculation with Vacuum Advance
Disconnect
Exhaust Gas Recirculation with Carburetor Modification
INTAKE MANIFOLD MODIFICATION - SUBTYPE 1.2.3
172(1)
384
430
440
Intake Manifold Modification
Air-Fuel Mixture Diffuser
Induction Modification
Air-Fuel Mixture Deflection Plate
CARBURETOR MODIFICATION - SUBTYPE 1.2.4
33
56
288(2)
295(2)
317
Carburetor Modification, Main Jet Differential Pressure
Crankcase Blowby and Idle Air Bleed Modification
Carburetor Main Discharge Nozzle Modification
Carburetor with Variable Venturi
Carburetor Modification with Vacuum Advance Disconnect
TURBOCHARGED ENGINE - SUBTYPE 1.2.5
100(1)
Turbocharger
FUEL INJECTION - SUBTYPE 1.2.6
22(1)
Electronic Fuel Injection
(1) Previously tested by EPA.
(2) Tested in retrofit program.
4-2
-------
4.1 AIR BLEED TO INTAKE MANIFOLD (RETROFIT SUBTYPE 1.2.1)
Within the induction control systems group of retrofit devices, there were nine de-
vices which operate on the principle of bleeding air into the intake manifold to
lean the air-fuel mixture. As shown in Figure 2-la (Section 2), with increasing
air-to-fuel ratio, CO decreases to a very low level. HC also decreases, though not
so significantly, and beyond some air-fuel ratio, increases again. Beyond an air-
fuel ratio slightly higher than stoichiometric, NOx begins to decrease. However, by
referring to Figure 2-lb, it can be seen that this reduction of NOx has an adverse
effect on engine power. With light duty gasoline-fueled engines, the high air-fuel
ratios at which NOx could be decreased are not achievable without degradating engine
performance to the point where the vehicle is practically undriveable. Thus air
bleed devices are mainly effective in decreasing CO, with moderate decrease of HC.
Leaning of the air-fuel mixture is used widely on new model-year vehicles. This, is
accomplished by lean idle adjustment and leaning the carburetor main circuit. An
air bleed device can provide leaning of the mixture through a variable orifice or
fixed orifice valve which is operated by intake manifold vacuum. This approach is
common to the air bleed devices evaluated in the retrofit program.
4.1.1 Device 1: Air Bleed to intake Manifold
Device 1 was one of two representative air bleed devices tested in the retrofit
study program (also see Device 42). This device is basically an air valve that
enables the air-fuel ratio to be increased by metering air to the intake manifold
in accordance with intake manifold vacuum. The device is continuously operative
at moderate through high intake manifold vacuums. The device is currently mar-
keted in production quantities.
4.1.1.1 Physical Description
Device 1 consists of a 3- by 8-inch cylinder incorporating an oil-damped air valve,
an intake adapter plate, and an air bleed hose. The adapter plate configuration
varies according to the carburetor and intake manifold interface requirements. The
air-valve cylinder mounts in the engine compartment, and the adapter plate installs
between the existing carburetor and the intake manifold. The hose connects the air
valve to the intake adapter plate.
Figure 4-1 shows the air valve cylinder and two adapter plate models. The cylinder
contains a valve which is adjustable by means of a threaded collar. The adjustment
collar, spring and valve shaft are housed in a reservoir of oil to dampen valve
oscillation under rapid changes in intake manifold vacuum. The cylinder is mounted
on a surface away from the motor, and because of the oil reservoir, must be mounted
in a vertical position.
An air filter, which must be cleaned or replaced at specified intervals, is integral
with the air-valve cylinder.
4-3
-------
BB041
Figure 4-1. DEVICE 1 AIR BLEED COMPONENTS
4.1.1.2 Functional Description
Device 1 operates on the principle of bleeding air into the intake manifold in pro-
portion to the manifold vacuum to increase air-fuel ratio. The additional air
oxidizes CO and HC more completely during the combustion process. When manifold
vacuum is high, such as at idle and on deceleration, CO and HC pollutants are high
and device air bleed is maximum. The device provides additional air supply during
these drive modes, so that the CO and (to a lesser extent) the HC can be oxidized to
carbon dioxide and water.
Figure 4-2 shows a schematic diagram of the device. The engine vacuum sensed through
the air hose opens a valve in the cylinder and allows controlled amounts of filtered
air into the intake manifold. This air mixes with the air-fuel mixture from the car-
buretor to increase the ratio of air to fuel. The adapter plate has a circular chan-
nel to promote a vortex for mixing the new air with the existing air-fuel mixture.
The air valve is adjusted by the threaded collar. Adjustment is maintained by the
collar locknut. Vibration and rapid movement of the valve is dampened by the oil in
the reservoir surrounding the adjustment collar.
To offset the effect of the air bleed at idle, the idle air-fuel mixture and speed
may have to be readjusted to achieve a smooth idle.
4-4
-------
VALVE
AIR FILTER
AIR
SPRING
OIL-
THREADED
VALVE SHAFT.
ADJUSTMENT COLLAR
COLLAR LOCK NUT
Figure 4-2. DEVICE 1 - FUNCTIONAL SCHEMATIC DIAGRAM
4.1.1.3 Performance Characteristics
Emission test results supplied by the developer in five cars are summarized in
Table 4-2. These tests were performed using the 1970 Federal Test Procedure.
During the retrofit study, the device was tested 18 times using the 1972 Federal
Test Procedure. The results are summarized in Table 4-3.
The developer's data (Table 4-2) indicates the expected high CO reduction (74 per-
cent), with considerably smaller overall reductions of HC and NOx. The results
obtained in the retrofit program tests are more representative of the emission
reduction effectiveness of this device, because of the greater number of tests.
The pooled mean emission reductions shown by these tests are 58 percent for CO and
21 percent for HC. NOx increased by 5 percent.
Device 1 was tested by EPA with similar results.
of these tests.
Table 4-4 summarizes the results
The EPA test report (Reference 76) concluded that the device is an effective con-
trol system for CO, with relatively lesser effect on HC. The increase in NOx was
an expected characteristic. This may be attributable to the additional oxygen
availability of the leaner fuel mixture. The EPA report noted that this increase
in NOx is minimized by the fact that the device cuts off the extra air under high
load operation (at which time the intake vacuum drops and the air valve spring
seats the valve).
The device was retested by EPA after 2,000 miles were driven on the 1970 Valiant.
This test indicated that CO and HC had decreased further.
4-5
-------
Table 4-2. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD EMISSION
RESULTS REPORTED BY DEVELOPER (1)
VEHICLE
YEAR/MAKE/CID
1969 Ford 8
Without Device
With Device
Percent Reduction
1968 Ford 8
Without Device
With Device
Percent Reduction
1968 Ford 6
Without Device
With Device
Percent Reduction
1970 Chev 8
Without Device
With Device
Percent Reduction
1966 Fiat 4
Without Device
With Device
Percent Reduction
HC
(PPM)
173
183
-6
285
329
-15
175
167
4
97
79
19
392
216
45
CO
C7^
\'o/
1.84
0.08
95
0.74
0.15
80
0.67
0.28
60
0.66
0.16
75
4.78
1.81
62
NOx
(PPM)
995
920
7.6
2,172
1,927
11
2,080
1,936
6.9
542
573
-6
750
367
50
(1) Tests performed for developer by Olson Laboratories as reported in Project
231-1, 20 May 1971, using 1970 Federal Test Procedure (Reference 15).
4.1.1.4 Reliability
The device manufacturer estimated a reliability exceeding 100,000 mean-miles-before-
total-failure (MMBTF). Physical examination of the device indicates that 75,000
miles is a realistic minimum MMBTF, based on the construction and small number of
moving parts. The oil damping should eliminate most conditions that would subject
the parts to stress and wear.
4.1.1.5 Maintainability
The only routine maintenance indicated is changing the air filter and checking the
air-fuel ratio. These maintenance actions could be performed at the same time the
engine air filter is changed every 12,000 miles. Filter cost is estimated at $2.50.
It is estimated that total maintenance time would take less than 0.3 hour, includ-
ing inspection and, if necessary, replacement of the 0-ring gasket which seals the
oil reservoir.
4-6
-------
Table 4-3. DEVICE I AIR BLEED TO INTAKE MANIFOLD EMISSION
REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/ CID
1965 Chev 194
Without Device
With Device
Percent Reduction
1965 Ford 289
Without Device
With Device
Percent Reduction
1965 Ply 318
Without Device
With Device
Percent Reduction
1965 Chev 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reduction
1961 Chev 283
Without Device
With Device
Percent Reduction
1965 VW 92
Without Device
With Device
Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS/MILE
HC
15.10
12.44
17.7
6.53
4,54
30.5
6.12
6.62
-8.2
7.06
6.72
4.8
8.35
6.61
L20.8
(2)
5 .83
(2)
10.81
5.79
46 o4
CO
135.37
143.93
-6.3
73.65
50.53
31.4
83.70
33.00
60.6
61.86
33.15
46.4
109.86
64.37
41.4
72.39
46.29
36.1
76.12
32.81
56.9
Pooler Mean Percent
Reduction (3)
NOx
0.84
1.27
-50.5
4.45
4.92
-10.6
5.74
4.79
16.6
3.35
2.86
14.6
2.32
2.32
0
2.92
2.55
12.7
1.69
1.48
12.4
FUEL
MILES/
GALLON
14.8
11.4
23.0
13.7
13.7
0
10.3
(2)
(2)
15.4
13.2
14.3
11.0
13.2
-20.0
12.5
14.8
-18.4
20.0
(2)
(2)
HC 21.0
TAYLOR TEST RESULTS
POLLUTANT
HC
5.36 4.15
3.16 4.02
41.0 3.1
4.94 4.63
3.63 4.31
26.5 6.9
7.68 5.98
9.91 5.81
-29.0 2.8
7.36 8.66
5.62 4.24
23.6 51.0
8.07 6.45
4.36 6.33
46.0 1.9
6.12
1.76
71.2
GRAMS/MILE
CO
55.78 57.96
5.95 12.80
89.3
77.9
69.81 39.88
14.44 26.06
79.3
34.7
74.87 42.04
5.15 11.31
93.1
73.1
99.55 109.96
25.86 40.51
74.0
63.2
72.94 56.03
36.18 26.55
50.4
52.6
37.50
5.44
85.5
CO 57.8
NOx
4.53 3.84
3.40 4.51
24.9 -17.4
5.77 5.48
4.97 4.13
13.9 24.8
6.88 5.10
6.90 6.06
-0.3 -18.8
3.48 3.20
4.47 5.04
-28.4 -57.5
3.34 2.75
3.22 3.66
3.6 -33.1
2.18
2.03
6.9
FUEL
MILES/
GALLON
11.6 12.6
13.7 (2)
-18.1 (2)
13.0 13.5
(2) 16.1
(2) 19.3
12.3 14.2
15.4 14.2
-25.2 0
13.0 10.7
14.5 13.7
-12.0 28.0
15.4 17.3
' 15.7 13.0
-2.0 24.4
21.2
15.1
29.0
NOx -4.8 Fuel -4 '
(1) Emission results obtained by Olson Laboratories in tests performed under Contract 68-04-0038
using 1972 Federal Test Procedure (Reference 3) Fuel consumption was measured during these
tests.
(2) Test data invalid.
(3) Anaheim and Taylor results combined.
4-7
-------
Table 4-4. DEVICE 1 EPA EMISSION TEST RESULTS (REFERENCE 76)
VEHICLE
CONFIGURATION (1)
Without Device (2)
With Device (3)
Percent Reduction
POLLUTANT (GM/MI)
HC
5.55
4.45
20
CO
80.90
44.95
44
NOx
3.9
4.5
-15
(1) 1963 Chevrolet Impala with 283-CID engine and
standard transmission and a 1970 Plymouth Valiant
with 225-CID engine and automatic transmission
(2) Average of one 1972 Federal Test Procedure
(Reference 3) on each vehicle.
(3) Average of seven tests performed in accordance
with the 1972 Federal Test Procedure. Four tests
were on the 1963 Chevrolet, and three were on the
1970 Plymouth.
No requirement for repair of the device is anticipated; however, the hose connecting
the device to the carburetor adapter plate might require replacement prior to 50,000
miles because of environmental conditions (such as ozone) and the amount of calendar
time to accumulate the mileage. Hose inspection would be a part of routine main-
tenance .
4.1.1.6 Driveability and Safety
This device was tested on six cars at both the Olson Laboratories' Anaheim and
Taylor test facilities. Table 4-5 summarizes the driveability results of these
tests.
As the data indicates, both acceleration and deceleration times increased, and gen-
eral driveability indicated longer starting time. Fuel consumption decreased by an
overall average of 4 percent, based on pooled fuel consumption data.
The EPA emission test report (Reference 76) pointed out that no adverse drive-
ability effects occurred during 2,000 miles of driving with the 1970 Valiant that
was tested. The report concluded that the vehicle was "...operating rich enough
to tolerate the enleanment effect."
There were no apparent safety hazards.
4.1.1.7 Installation Description
Table 4-6 lists the steps necessary for installation of this device.
a sketch of a typical installation.
Figure 4-3 is
4-8
-------
Table 4-5. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DR|VEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON (1)
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON (1)
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1
No effect
Reduced starting
time and .number
of attempts
during hot
start test
Increased from
17.8 to SO. U
Increased from
18.5 to 21.2
CAR NO. 2
No effect
No effect
Increased from
12.0 to 12.6
Increased from
15.5 to 23.0
Average increaf
CAR NO. 3
Reduced the ten
dency to stall
during cold
start test
No effect
Increased from
12.8 to lU-3
Increased from
23-5 to 25
CAR NO. 4
Reduced the
tendency to
stall during
cold start
test
Reduced start-
ing time in
cold start test
Increased from
11.5 to 12.5
Increased from
22 to 23
CAR NO. 5
No effect
Reduced start-
Ing time during
hot start test
Increased from
9-5 to 10. It
Decreased from
28.9 to 22
CAR NO. 6
No effect
Increased
stumble during
cold start
acceleration
Increased from
15.9 to 17.1
Increased from
20-5 to 26.2
e of 0.5 percent (reference Table 4-3)
TAYLOR, MICH., DRIVEABILITY TEST RESULTS
CAR NO. SO
Bo effect
Hot starting
time increased
slightly
Increased from
32.lt to 3h.e
Information
not available
CAR NO. 8
No effect
Increase in
cranking time
and number
attempts to
start
Increased from
11.5 to 12.8
Increased fro':-
20.9 to 21.2
CAR NO. 9
Showed increase
in rough idle
and stalls on
1st test but
not on re-
plicate test
Replicate test
showed increase
in hesitation
and stumble
Increased from
13.lt to 13.6
Increased from
22.0 to Sit. 9
CAR NO. 10
No effect
Increase in
hesitation
and stumble
Increased from
10.3 to 11.0
Decreased from
all. 3 to 23.6
CAR NO. 11
Rough idle
improved with
device install-
ed increased
on stall with
1st test
No change in
driveability
Increased from
10.3 to 12.0
Increased from
22.1 to 23-2
CAR NO. 12
No effect
Cranking time
increased
for both hot
and cold
starts.
Increased from
12.5 to 12.9
Increased from
2lt.3 to 27.2
Average Increase of 6.4 percent (reference Table 4-3)
(1) Ponied mean increase In miles per gallon equals 4 percent.
4-9
-------
Table 4-6. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MIN.)
1. Start up engine; after reaching normal
operating temperature, hookup vacuum
gauge, tachometer, and exhaust analyzer
2. With engine running, record vacuum, idle
rpm, percent CO, and percent combustion
3. Stop engine
4. Remove carburetor from engine intake
manifold. Remove studs
5. Screw studs supplied with kit into intake
manifold
6. Assemble supplied adapter plate over
manifold studs with new gaskets, also
supplied in kit
7. Replace carburetor on manifold, check all
linkages and adjust as necessary
8. Mount reservoir bracket to vertical sur-
face in engine compartment with screws
supplied in kit. Mount as near to
adapter plate as possible and as near to
vertical as possible
9. Assemble and clamp one end of the hose
supplied in the kit to the outlet snout
of reservoir and the other end to the
inlet of the adapter plate
10. Screw large counterweight nut at the bot-
tom all the way in, compressing the spring
11. Start engine, adjust idle mixture and
balance idle mixture screws to get the
smoothest idle at the recommended idle
speed. Combustion efficiency should be
approximately 75-80 percent. (1)
a. Vacuum gauge
b. Tachometer
c. Exhaust analyzer
15
Hand tools
a. Hand tools
b. Studs
a. Hand tools
b. Gaskets
c. Adapter plate
Hand tools
a. Hand tools
b. Electric drill
c. Sheet metal screws
d. Bracket
a. Hand tools
b. Hose
c. Clamps
Hand tools
a. Hand tools
14
10
4-10
-------
Table 4-6. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD
INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
12. With engine running at normal operating
temperature, unscrew large counterweight
nut at bottom until the vacuum gauge
level reads about 1 to 3 inches Hg below
the previously recorded vacuum at the
same rpm (smaller engines 1 to 2 inches
Hg, larger engines 3 inches Hg)
13. Tighten stop nut against counterweight
and set into reservoir bracket
14. Fine adjust counterweight to bring com-
bustion efficiency above 85 percent (1)
15. Fill reservoir with 1-1/2 inches of
automatic transmission fluid and tighten
lock screw on outside
16. Remove all test equipment
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b . Vacuum gauge
Hand tools
a. Hand tools
b. Exhaust analyzer
a. Hand tools
b. Transmission fluid
c. Reservoir
TIME
(MIN.)
3
2
10
1
2
(1) The expression "combustion efficiency" refers to the calibration used on
some engine analyzers for adjusting the air-fuel ratio for lowest emissions
commensurate with satisfactory engine performance. Other analyzers use
percent carbon monoxide. The expression used in this table is that used by
the developer.
The developer stated that, as a prerequisite to device installation, the automotive
engine should be in good operating condition if the expected performance is to be
achieved. Any malfunction should be repaired and the engine tuned up before device
installation. The exhaust system should also be checked and any leaks repaired.
Installation of this device consists in placing the adapter plate between the car-
buretor and intake manifold, mounting the air valve on a vertical surface in the
engine compartment, and connecting the two with a hose. The adjustment required
after installation consists in setting the counterweight in the device to obtain a
vacuum reading of 1 to 3 inches below that obtained without the device installed,
and adjusting the carburetor settings to get a combustion efficiency above 85
percent.(1) The developer estimated that one hour of labor would be required for
installation. Installation could be accomplished in a normally equipped garage by
the average mechanic. The carburetor adjustment requirement would preclude instal-
lation by the average vehicle owner.
(1) Refer to footnote, Table 4-6.
4-11
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adaptor plat*
AV.B.
[mounted vertical)
(FRONT)
-in*ide wall of
engine compartment
Figure 4-3. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD
TYPICAL INSTALLATION (DEVELOPER SKETCH)
4.1.1.8 Initial and Recurring Costs
The developer stated that for most cars kits and parts cost $40, but that the
special adapter plates might increase the kit cost to $48 for some four-barrel
carburetors. Table 4-7 is a summary of the initial and recurring costs in-
volved.
4.1.1.9 Feasibility Summary
Results of data developed during the retrofit study test program showed that the
device did not affect driveability unsatisfactorily and on the average decreased
CO significantly with some decrease in HC. NOx increased slightly. The device
appears to be reliable, relatively low in cost, and simple and inexpensive to
install and maintain; and offers a return on investment through fuel savings.
Since the device indicates cost-effective reduction of CO and HC, and is presently
available on the market, it appears to be a reasonable candidate for retrofit use.
Applicability of the device would appear to be more effective for those vehicle
model years not already incorporating lean air-fuel mixture. This would include
most vehicles prior to 1968. As noted in the EPA emission test report (Reference
76), any further leaning of the later model vehicles might cause misfire or the
adverse driveability characteristics associated with excessively lean air-fuel
mixtures.
4-12
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Table 4-7. DEVICE 1 AIR BLEED TO INTAKE MANIFOLD INITIAL AND
RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Adapter plate
b. Reservoir
a. Intake manifold
studs
b. Gaskets
c. Sheet metal screws
d. Hose '
e. Hose clamps
f . Transmission .fluid
Table 4-6
LABOR HOURS OR
ITEM QUANTITY
1 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material . "
1. Fuel . .
2. Filter
Labor
1. Inspection
.Average fuel savings
of 4 percent
Air valve
Filter, carburetor
mixture adjustment,
and hose inspection
Savings of 160 gal.
x $0.35/gal. (1)
$2.50 each at four
replacements during
service life
0.3 hr at $12.50/hr
Total Recurring Cost
TOTAL COSTS .
COST
(DOLLARS)
40.00-48.00
(Included
in above)
12.50
3.12
$55.62-63.62
-56.00
10.00
3.75
-42.25
$21.37
(1) Based on an assumed national average of 10,000 miles per year at 12.5 mpg,
fuel savings equals 4 percent of 4,000 gallons.
4-13
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4.1.2 Device 42: Air Bleed to Intake Manifold
This device operates on the same principle as the other air bleed devices studied.
The main differences between this and cue other devices in this category are in the
periods when the air bleed is operative and in the method of controlling the amount
of additional air that is allowed to enter the intake manifold. Device 42 operates
as an air bleed to intake manifold at low to moderate vacuums. During high intake
manifold vacuum, the airflow through the device is restricted.
This device was included as a test specimen in the initial phase of the retrofit
study.
4.1.2.1 Physical Description
Device 42 is shown in Figure 4-4. The device consists of an air valve which meters
air from the carburetor air cleaner to the intake manifold in two places through
dual air hoses. The air valve is T-shaped. Each leg is about 3 inches long and
1 inch in diameter. The outlet of the stem of the T accepts a hose which attaches
to the air cleaner. The other two outlets at each end of the bar of the T accept
hoses which connect to two locations on the intake manifold.
Inside the valve are three plastic balls which control the amount of air bleed
between the air filter and manifold. The case of the valve is made of plastic,
and the hoses are rubber. Push connector nipples are used to connect the hoses to
the manifold and air cleaner.
CARBURETOR AIR-
CLEANER HOSE
HOSES TO INTAKE MANIFOLD
Figure 4-4. DEVICE 42: AIR BLEED TO INTAKE MANIFOLD
4-14
-------
4.1.2.2 Functional Description
Figure 4-5 shows a functional diagram of the device. Under low and medium vacuum,
air bleeds from the air cleaner to the intake manifold. Under high vacuum, such
as at idle or deceleration, the plastic balls deform and restrict the flow of air.
The air inlet leg can be adjusted to vary the length of the chamber containing the
plastic balls. Adjustment of air bleed is accomplished by varying the chamber
length.
AIR FILTER.
TO INTAKE
MANIFOLD.
DURU10 VACUUM DEMAND —
THE PLASTIC BALLS WILL
DEFORM ALLOWING A
MBTERED AMOUNT OF AIR
TO PASS THROUGH THE
DEVICE INTO THE AIR
INTAKE MANIFOLD.
AT EXTREME VACUUM THE -
PLASTIC BALLS EXPAND
III GIRTH AND START
RESTRICTING THE AIR
FLOW THROUGH THE DEVICE
DUE TO THE FREQUENT
DEFORMING AND FLEXING
OF THE PLASTIC BALLS
CARBON BUILDUP IS
ELIMINATED.
THE FED DEVICE IS
MOUNTED BELOW THE
CARBURETOR ON THE
INTAKE MANIFOLD.
AIR IS DRAWN BI
MEANS OF ENGINE
VACUUM INTO THE
INTAKE MANIFOLD.
CONTROL OF THE
AIR IS MAINTAINED
BY ENGINE VACUUM
DEMAND.
THE PROBLEM ENCOUNTERED ON MOST SPRING LOADED BALL VALVES OF SHOCK AND VIBRATION
CAUSING ALTERATIVE LEANING AND RICKENING OF THE FUEL KUTURS.DUE TO ROUGH ROAD3
IS ELIMINATED IN THE FED DEVICE.BECAUSB THE PLASTIC BALLS ABSORB Am SHOCKS OR
VIBRATION ENCOUNTERED.
Figure 4-5. DEVICE 42 AIR BLEED TO INTAKE MANIFOLD FUNCTIONAL
SCHEMATIC (DEVELOPER DIAGRAM)
The effect of the air bleed is to increase the air-fuel ratio during normal operation,
but not during idle or deceleration when intake vacuum is highest. When the plastic
balls deform under these high vacuum conditions, the air bleed is minimum and air-
fuel mixture ratio is not changed from that normally supplied by the carburetor. Shut-
ting off the air bleed at idle in this manner prevents a rough idling engine.
Adjustment of the valve is done at medium rpm to minimize HC and CO. Leaning and
richening of the mixture from vibration and shock is avoided by the shock absorp-
tion capability of the plastic balls. The overall effectiveness of this device
would appear to be influenced primarily by the material composition of the plastic
balls utilized.
4^15
-------
4.1.2.3 Performance Characteristics ,
The developer of the device provided emission data on four automobiles and during
the retrofit study the device was tested on two automobiles. The results of these
tests are summarized in Tables 4-8 and 4-9. The average percentage emission reduc-
tions for the two tests performed in the retrofit program were 45.3 for CO, 23.2
for HC, and 2.6 for NOx. These test results indicate that Device 42 is effective
in decreasing CO and, to a lesser extent, HC.
4.1.2.4 Reliability
The device may be subject to aging of the plastic material used in its construction
and cyclic fatigue loading of the balls used as a valve. Provided optimum plastic
compositions have been selected, reliability would be estimated to exceed 75,000
MMBTF.
The selection of optimum plastics should include consideration of:
1. Complete operating temperature profile
2. Compatibility with fuel and other organics present in the engine
compartment
3. Geographical climate extremes of temperature for cold engine
starts and very hot running
4. Resistance to deterioration from ozone
5. Fatigue life of the ball material.
The entire valve assembly, being a low cost item, might be considered for
replacement during routine maintenance, if required to meet the system
reliability requirement.
4.1.2.5 Maintainability
The only periodic maintenance of the device would be to clean the air filter
every 12,000 miles. Replacement would be recommended for visually deteriorated
components such as hoses or the valve housing. It is estimated that filter
cleaning or any replacement could be accomplished in less than 15 minutes.
No routine adjustment of the air valve would appear to be necessary.
4.1.2.6 Driveability and Safety
This device was tested for driveability as part of the retrofit study with
results shown in Table 4-10.
During the period of this test, Car No. 4 was continuously on the verge of poor
performance when cold. The comments shown in Table 4-10 for this car may
possibly be attributed to a shift in performance of the vehicle more than the
fault of the device.
As is characteristic of air bleed devices, fuel economy appeared to improve. One
4-16
-------
Table 4-8. DEVICE 42 AIR BLEED TO INTAKE MANIFOLD EMISSION REDUCTION
AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR /MAKE /C ID
1965 Chev 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reduction
Average Reduction 7o
ANAHEIM TEST RESULTS
POLLUTANT GRAMS /MILE
HC
6.15
6.62
-7.6
14.14
6.50
54.0
23.2
CO
66.49
33.34
50.0
150.50
88.94
40.9
45.3
NOx
3.25
3.35
-3.1
3.72
3.41
8.3
2.6
FUEL
MILES/
GALLON
13.70
13.70
0
10.42
11.93
-14.5
- 7.2
(1) Emission results obtained by Olson Laboratories in tests performed
under Contract 68-04-0038 using 1972 Federal Test Procedure (Reference 3),
Fuel consumption was measured during these tests.
Table 4-9. DEVICE 42 MEAN EMISSION TEST RESULTS BASED
ON TESTS REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT
HC (PPM)
453
311
26
CO (7.)
4.44
1.39
45
NOx (PPM)
892
919
-3
(1) HC and CO are averages of three 7-cycle, 7-mode tests on 1967 Ford,
1967 Pontiac, and 1970 Renault with and without device installed;
NOx is based on one test of the Renault.
test showed no change in fuel consumption, while the other test showed an improve-
ment of 147o in gasoline mileage.
4-17
-------
Table 4-10. DEVICE 42 AIR BLEED TO INTAKE MANIFOLD
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
•r GAS MILEAGE
PER GALLON
1965 CHEV.
.194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV. .
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1
(i) :
CAR NO. 2
U)
CAR NO. 3
(1)
CAR NO. 4
Increased stall
on deceleration
during cold
start test
Rough idle
during cold
start test; re-
duced hesita-
tion during
cold start test
Increased from
11. T to 12.2
Increased from
23-7 to 2l).2
CAR NO. 5
No effect
Decreased de-
tonation during
hot start
acceleration
Increased from
10.0 to 10.2
Increased from
23-7 to 26.7
CAR NO. 6
(1)
Average Increase of 7.3 percent (reference Table 4-8)
(1) Device No. 42 was not tested on these vehicles.
No safety hazards were identified. If one of the air restriction balls were
ingested into the intake manifold, it is not likely that engine failure would be
catastrophic.
4.1.2.7 Installation Description
The installation of this device consists in drilling two holes in the intake man-
ifold and one in the air filter, and connecting these points with rubber tubing in
which the device is installed. The air valve may be installed on the fire wall,
fender well,-or directly on the carburetor air cleaner housing. Figure 4-6 shows
the latter installation.
Adjustment of the device after installation is accomplished by reading the value
of CO on an engine exhaust analyzer, and adjusting the air inlet leg to give the
desired reading. Engine rpm at idle may require adjustment.
4-18
-------
ERED AIR HOSE
Figure 4-6. DEVICE 42 AIR BLEED TO INTAKE MANIFOLD: TYPICAL
INSTALLATION OF AIR VALVE ON CARBURETOR AIR
CLEANER (DEVELOPER PHOTO)
Table 4-11 itemizes the installation procedure. Installation can be accomplished
in a normally equipped repair shop by the average mechanic. From the information
available, it is estimated that installation of this device, including material,
would be $22.50.
4.1.2.8 Initial and Recurring Costs
Table 4-12 summarizes the initial and recurring costs for the device. The developer
estimated an initial cost of less than $10 for the device. As with most devices
of this type, the fuel saving (if any) eventually would pay off the initial cost.
Device 42 could provide a return on investment after about one year of use.
4.1.2.9 Feasibility Summary
This device appears to be practical for retrofit on some older cars if careful tune-
ups are performed to adjust for low emissions. Tests of this device showed that
driveability and acceleration times were affected very little by installation of
this device, while exhaust emissions showed a significant reduction of CO. No
safety hazards appear to exist, and the device is relatively inexpensive to purchase,
install, and maintain, with even some cost return through a fuel economy saving.
4-19
-------
Table 4-11.
DEVICE 42 AIR BLEED TO INTAKE MANIFOLD
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MIN.)
1. Make sure the air filter is clean.
2. Clean or replace PCV valve.
3. Examine intake manifold to find the
best location to install 1/4-inch
push connector nipples.
4. Drill two 15/64-inch holes. (Use
strong magnet to collect drill chips)
5. Tap nipples gently into the holes.
Leave the machine screws in the
nipples for this operation.
6. Remove the machine screws from the
nipples and connect the rubber tubes
to nipples and device.
7. Drill one y/16-inch hole in lower
half of the air filter casing to re-
ceive air hose plastic securing
bushing. In an oil bath filter drill
into upper section.
8. Push air hose and plastic bushing
into the 9/16-inch hole
9. Adjust by CO reading on exhuast
analyzer. If CO is too low, close
device about half a turn. If CO
is too high, unscrew the device
about a half a turn.
10. Adjust rpm with carburetor idle
screw
Hand tools
a. Electric drill
b. Magnet
a. Hand tools
b. Nipples
a. Hand tools
b. Rubber tubes
Electric drill
a. Air hose
b. Plastic bushing
Exhaust analyzer
Tachometer
3
10
3
10
17
Total Time
1 hr
4-20
-------
Table 4-12. DEVICE 42 AIR BLEED TO INTAKE MANIFOLD
INITIAL AND RECURRING COSTS
ITEM
DESCRIPTION
LABOR HOURS OR
ITEM QUANTITY
COST
(DOLLARS)
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
a. Nipples
b. Rubber tubing
Table 4-11
0.75 hr
0.25 hr
10.00
(Included
in above)
9.38
3.12
Total Initial Cost
$ 22.50
50,000-Mile
Recurring Cost:
Material
1. Fuel
Labor
1. Filter
Average fuel
savings of
7 percent
Clean Air Filter
280-gal. fuel reduc-
tion x $0.35 per
gallon over 50,000
miles (1)
Once every 12,000
miles @ 0..25 hr each
= 1 hr for 50,000
miles, or $12.50
-98.00
12.50
Total Recurring Cost
-$85.50
TOTAL COSTS
-$63.00
(1) Based on an assumed national average of 10,000 miles per year at
12.5 mpg, fuel savings equals 7 percent of 4,000 gallons.
4-21
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4.1.3
Device 57:
Disconnect
Air Bleed with Exhaust Gas Recirculation and Vacuum Advance
This device shows the effects of combining exhaust gas recirculation and distributor
vacuum advance disconnect with air bleed into the intake manifold. The air bleed
and exhaust gas recirculation is operational at moderate through high intake mani-
fold vacuums, and vacuum disconnect is continuous unless the engine overheats.
This approach should provide an increased amount of air for reduction of HC and CO
emissions during combustion, along with reduction of combustion temperatures to
inhibit NOx emissions. The increased exhaust gas temperature should promote fur-
ther oxidation of CO and HC in the exhaust ports and manifold.
4.1.3.1 Physical Description
As shown in Figure 4-7, Device 57 consists of an adapter plate that installs be-
tween the carburetor and the intake manifold, a dashpot to mount on the plate, and
a temperature sensitive switch to disconnect vacuum to the distributor vacuum
advance mechanism. The adapter plate is approximately 1 inch thick and is made of
aluminum. It contains a butterfly valve type of flow sensor with lips on the edge
to meter air and exhaust flow into the manifold from jets which protrude into the
throat.
The dashpot mounts on the adapter plate to dampen oscillation of the flow sensor.
The temperature sensitive switch, which is designed to be mounted in the radiator,
is about 3/4 inch in diameter and 2 inches long. Two hoses connect it to the dis-
tributor and vacuum source.
VACUUM DISCONNECT
HOSE
EGR VALVE
AND ADAPTER PLATE
ASSEMBLY
Figure 4-7. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE DISCONNECT
SYSTEM COMPONENTS
4-22
-------
4.1.3.2 Functional Description
The system operates on the principle of metering exhaust gas and filtered air
into the intake manifold as a function of air-fuel mixture flow through the
carburetor. The vacuum advance to the distributor is normally disconnected,
but is reconnected if the engine overheats. The distributor vacuum advance is
disconnected through a standard temperature-sensitive vacuum switch.
The adapter plate contains an exhaust gas circuit and a filtered air circuit.
Both circuits are controlled by identical valves with no moving parts. The
developer reported that "the flow through both valves is regulated by a single
sensor having one moving part. The sensor responds to airflow through the
engine. Attached externally to one side of the plate is a dashpot to dampen the
'hunting1 action of the sensor."
The following principles of operation are quoted from the developer's data for
the exhaust gas recirculation circuit and for the filtered air circuit:
"EGR Circuit:
"Exhaust gases are recirculated into the intake manifold in varying
amounts in proportion to the cubic feet of air being consumed by the
engine. The total volume of recirculation can be preset for a given
engine model before installation. Since the exhaust gases do not contact
any of the metering mechanism, corrosion or scale buildup does not occur
to alter metering action with mileage accumulation.
"Filtered Air Circuit;
"Identical in operation to the EGR circuit, but with the inclusion of an
adjustable needle to regulate, or block, filtered air flow. This circuit
is used to lean out the carburetor above idle without having to make
internal changes inside the carburetor.
"This system will reduce HC, CO and NOX to acceptable levels on used cars.
"The function of the system can be roughly divided into three sections:
1. Recycling a metered amount of exhaust gases through the engine.
2. Adjusting the air-fuel ratio of the carburetor without internal
alterations of the carburetor.
3. Disconnecting the vacuum spark advance through the conventional
thermostatic protection switch.
"Items 1 and 2 are accomplished through the use of a shutoff-metering
valve combination which is sensitive to airflow through the intake mani-
fold, and will introduce the predetermined amount of exhaust gases (or
filtered air) required for any mode of engine operation.
4-23
-------
"Since there are no moving parts in the valve and only one moving part (in
the overall assembly), the complete assembly can be incorporated into a plate
to be installed between the existing carburetor and the intake manifold."
"Once installed, the operational adjustments consist of regulating the
amount of filtered air found to be necessary on each engine, using a
garage type exhaust gas analyzer at idle speed and at 2,500 rpm no load.
No adjustment of exhaust gas recycling is necessary as the orifice
restricting total flow has been predetermined on each engine type for
maximum emission reduction compatible with acceptable driveability. Less
than total flow is, of course, metered by the valve in proportion to air
flow through the engine. (The valve sensor responds to air volume moving
through the intake manifold.)"
4.1.3.3 Performance Characteristics
This device was tested on a 1957 Chevrolet by the developer. The test proce-
dure and test results are described in the following excerpts from information
supplied by the developer:
"The vehicle selected was a suspected high emitter for the purpose of
demonstrating the device's ability to perform reductions in HC-CO due
to carburetor conditions which ordinarily would require internal
carburetor service.
"After completion of all testing, the carburetor was torn down and
inspected. It was found to have float level at 3/4 inch (factory speci-
fication), main jets were 7002656 (factory specified Sea Level jet) but
jets were scarred and battered. Vent valve distorted as to be contin-
uously open.
"The owner's repair bill of a month previous lists new spark plugs, points,
condenser, carburetor repair kit, and PCV valve.
"It can be argued that the greater part of the HC*-CO reduction achieved
could have also been gained by correct adjustments and/or repair to the
carburetor. But, using the device, such conditions were improved without
internal carburetor service. However, the relation of CO to NOX before
and after, suggests that the percent reduction of NOX by the device is
accurate. The 'with device' test was run after the device had been
installed and adjusted by the 'emergency method1." (1)
Table 4-13 shows the results of the test. These results indicate that the device
may be effective in reducing all three exhaust pollutants. Further testing would be
required to verify that these results can be obtained consistently for a variety of
used cars.
(1) Refer to Table 4-14, Item 9c, for definition of the emergency method of
Device 57 adjustment.
4-24
-------
Table 4-13. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE DISCONNECT
EMISSION TEST RESULTS REPORTED BY DEVELOPER
VEHICLE
CONFIGURATION (1)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
10.81
4.78
55.8
CO
85.62
40.85
52.3
NOX
2.23
1.19
46.6
(1) 1957 Chevrolet with 283-CID engine with dwell at 30 degrees, timing
advance line disconnected and plugged at 8 degrees, 500-rpm idle
without device and 550 rpm with the device (both with transmission
in drive, and idle mixture set to best idle for highest rpm). One
7-cycle, 7-mode test with and without device installed.
4.1.3.4 Reliability
The carburetor adapter plate subsystem concept appears capable of demonstrating
a reliability in excess of 50,000 MMBTF with satisfactory maintenance. Addition-
ally, the thermostatic override control for the distributor vacuum advance
appears capable of demonstrating an acceptable reliability. Essential to this
successful demonstration is proper installation.
4.1.3.5 Maintainability
It is anticipated that the use of a detergent bearing gasoline, or the periodic
use of carburetor.detergent gasoline additives, would maintain the exhaust gas
valve areas sufficiently clean to preclude the need to remove the carburetor
for periodic maintenance every 12,000 miles. Tests of this concept should be
carried out to verify its validity. Periodic maintenance every 12,000 miles
would include:
1. Inspection and cleaning of the air bleed filter
2. Manual actuation of the valve shaft to assure that it is free to
fully rotate and that the vacuum diaphragm is intact
3. Inspection of the thermostatic override control for the vacuum
advance.
It is estimated that normal maintenance could be accomplished in approximately
25 minutes (0.4 hour).
No repair is anticipated prior to 50,000 miles; however, replacement of the
thermostatic control might be required. The method of installation indicated
by the developer would preclude removal of an installed control, requiring
installation of a replacement control in an adjacent location. It is estimated
that this repair could be performed in 60 minutes.
4-25
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4.1.3.6 Driveability and Safety
Driveability data provided by the developer indicated no major adverse effect on
the vehicle's performance as a result of device installation. General driveability
was characterized by increased rough idle during cold start and increased stretchi-
ness during cold start acceleration. These are typical characteristics of air
bleed systems.
In the event the thermostatic control fails such that the distributor vacuum advance
is continuously inoperative, engine overheating could occur. Also, the probability
of having a carburetor backfire is increased by the method of exhaust gas recircula-
tion used. This would constitute a fire hazard if the carburetor used with the
device is not capable of suppressing a backfire.
4.1.3.7 Installation Description
The installation of this device consists in mounting the combination adapter plate
and valve between the carburetor and intake manifold, installing a vacuum discon-
nect switch, and connecting vacuum hoses to carburetor and distributor through the
vacuum disconnect switch. Figure 4-8 shows the adapter plate and valve installed
on a V-8 intake manifold with the carburetor.
TOP
BOTTOM
Figure 4-8. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE DISCONNECT
INSTALLED ON V-8 INTAKE MANIFOLD (DEVELOPER PHOTO)
Adjustment of the engine consists in setting the carburetor and ignition to auto-
mobile manufacturer's specifications with the following exceptions. Idle speed for
cars with automatic transmission should be adjusted to 50 rpm over factory specifi-
cations while cars with standard or overdrive transmissions should be adjusted to
75 rpm over factory specifications. Idle mixture should be adjusted to obtain 86
4-26
-------
percent efficiency using a combustion analyzer.(1) Adjustment of the device
adapter plate air adjustment consists in running a dynamometer test and adjusting
the screw on the adapter plate to obtain 0.8 to 1.0 percent CO. Alternate proce-
dures are specified by the developer if a dynamometer is not available (refer to
Table 4-14, Item 9).
The developer stated that installation would have to be in thoroughly controlled
facilities where equipment and personnel can be relied upon to adjust and service
the unit properly. He stated that this device is not recommended for over-the-
counter sales with no guarantee on how it will be installed or adjusted. The
developer estimated that it would take 1.8 hours of labor to install and adjust
this device.
Table 4-14 contains a detailed description of the installation procedure and
identified tools and special equipment required as well as time. Installation can
be accomplished in a normally equipped repair shop by the average mechanic.
Table 4-14. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE
DISCONNECT INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
Remove carburetor and mounting
studs.
Clean manifold surfaces and install
longer studs.
Using new gaskets, slip device plate
over studs and reinstall carburetor.
(Large majority of engines have
existing exhaust holes which will
automatically feed exhaust gases
into device plate. Those that do
not, slip drill template over studs
and drill with 3/8-inch electric
drill.)
Inspect and readjust if needed;
linkages, shift rods, kickdown
switches, etc.
If cross-over type choke is used, a
choke rod extrusion is furnished to
be snapped onto existing choke rod.
Install vacuum disconnect switch kit
in radiator and route vacuum hoses
to carburetor and distributor.
a.
b.
Hand tools
Hand tools
Longer studs
15
a. Hand tools
b. Drill template
c. 3/8-inch electric drill
20
Hand tools
a. Hand tools
b. Choke rod extrusion
a. Hand tools
b. Switch kit
12
(1) Refer to footnote, Table 4-6, on Page 4-11,
4-27
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Table 4-14. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE
DISCONNECT INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
Adjustments - Factory carburetor and
ignition specifications apply with
these exceptions:
7. Idle speed (automatic transmission)
a. In drive, factory specifications
plus 50 rpm or
b. Idle speed (standard and over-
drives) , factory specifications
plus 75 rpm.
8. Idle Mixture
a. 0.9 to 1.2 percent CO or
b. 86 percent (1) or
c. Best lean idle.
9. Device Plate air adjustment
a. Follow Clayton Key Mode pro-
cedure for "high cruise" while
adjusting screw to read CO 0.8
to 1.0 percent or
b. 2,200 rpm in neutral, adjust to
1.2 percent +0.1 CO or 87
percent +1 combustion (1) or
c. Emergency method only:
2,200 rpm in neutral, slowly
turn air screw out from its
seat until lean roughness is
detected then turn screw in
one full turn.
(Note: Device plate air screw
does not operate at curb idle.)
TOOLS, EQUIPMENT
AND FACILITIES
Tachometer
Infrared analyzer or
combustion analyzer.
a. Dynamometer and
analyzer
b. Analyzer and tachom-
eter
c. Tachometer
TOTAL TIME
TIME
(MIN.)
3
18
24
1.75 hr
(1) The expression "combustion efficiency" refers to the calibration used on
some engine analyzers for adjusting the air-fuel ratio for lowest emissions
commensurate with satisfactory engine performance. Other analyzers use-
percent carbon monoxide. The expression used in this table is that used by
the developer.
4-28
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4.1.3.8 Initial and Recurring Costs
The developer estimated that the cost of the device installed would be $55. Table
4-15 summarizes the installation costs. From the information available, it was
estimated in the retrofit study that the total cost for installing this device,
including material, would be $62.88.
4.1.3.9 Feasibility Summary
Device 57 test results provided by the developer for one automobile indicate effec-
tive reduction in all three exhaust emissions. If further testing shows similar
emission reduction for other cars, the device would appear to be technically feas-
ible as a retrofit device for older cars.
Table 4-15. DEVICE 57 AIR BLEED WITH EGR AND VACUUM ADVANCE DISCONNECT
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
One piece plate with
two valves and sensor
controlling air and
exhaust gas
a. Studs for intake
manifold
b. Template for
drilling
c. Switch kit
d. Vacuum hose
e. Choke rod ex-
tension
Table 4-14
LABOR HOURS OR
ITEM QUANTITY
1 hr
0.75
Total Initial Cost
50,000-Mile
Recurring Cost:
Labor
1. Inspection
Refer to paragraph
4.1.3.5
0.4 hour every
12,000 miles at
$12.50 per hour
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
41.00
(Included in
above)
12.50
9.38
$62.88
20.00
$20.00
$82.88
4-29
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4.1.4 Device 325/433: Air Vapor Bleed to Intake Manifold
Devices 325 and 433 are identical alcohol-water vapor injection systems being mar-
keted by different companies. Though these devices are generally referred to as
vapor injectors, their basic effect appears to be that of an air bleed to the intake
manifold. Direct air bleed is provided at idle and alcohol-water-air vapor bleed
is provided at all other engine speeds and loads.
Alcohol-water injection has been used for many years in aircraft and race cars as a
means of obtaining maximum power. The objective in these applications has been to
operate at higher air-fuel ratios than would be possible without injection. The
alcohol-water injection provides detonation control for the higher engine perform-
ance ranges and also cools the various combustion parts. Exhaust emission research
in recent years has indicated that use of alcohol-water injection may provide the
cooler combustion flame temperatures that inhibit NOx formation without power loss
(Reference 77). This research also has indicated that under some engine modes the
reduction of HC is also enhanced.
4.1.4.1 Physical Description
The Device 325/433 injection system consists of four basic components and intercon-
necting hoses. The basic system components, as shown in Figures 4-9 and 4-10, are:
1. A plastic fluid storage bottle measuring 7-1/2 by 7-1/2 by 10 inches and
weighing about 2 pounds empty.
2. A plastic metering valve to control injection of alcohol-water vapor
mixture.
3. A fiber adapter plate to fit between the carburetor and intake manifold.
4. Idle adjustment air needles to replace those normally supplied for the
carburetor.
The fluid storage bottle is mounted in the engine compartment away from exhaust
heat. It is connected through hoses and the valve to the carburetor adapter plate
and to the PCV valve. The idle air needles are screwed into the carburetor to
replace the normal idle adjustment screws. These screws have an air passageway
drilled their entire length.
4.1.4.2 Functional Description
The vapor injection system operates on the principle of injecting an alcohol-water-
air vapor into the intake manifold, to improve mixture thermal capacity, increase
power, and reduce emissions.
Figure 4-11 illustrates a typical system functioning on a V-8 engine. Air is bled
into the carburetor air-fuel mixture directly through the special idle needles,
leaning the air-fuel mixture at idle. The alcohol-water-air vapor mixture is drawn
into the intake manifold through the PCV inlet downstream of the PCV valve. The
metering valve operates on a low vacuum and supplements the flow of crankcase blow-
by from the PCV valve to the manifold with the alcohol-water-air vapor from the
fluid storage bottle. A metering orifice downstream of the valve, limits the total
flow of vapor.
4-30
-------
ALCOHOL
ADDITIVE
ALCOHOL-WATER
STORAGE BOTTLE
BB039
CARBURETOR-MANIFOLD
ADAPTER PIATE
Figure 4-9. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD SYSTEM COMPO-
NENTS (REFER TO FIGURE 4-10 FOR AIR NEEDLES)
Figure 4-10. DEVICE 325/433 AIR INJECTION NEEDLES
4-31
-------
Figure 4-11. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD
FUNCTIONAL SCHEMATIC (DEVELOPER DIAGRAM)
Vapor is achieved in the fluid storage bottle by venting the bottom of the
fluid to atmosphere and drawing a vacuum on the bottle above the fluid level,
causing the air to pass through the liquid. The developer provides the
following information in his sales brochures to describe operation and theory
of the device:
"The Vapor Injector is connected to the carburetor by means of a
vacuum line or an adapter plate, and the suction created by normal
engine operation draws fresh air into the top of the liquid con-
tainer. This air goes down through the polycarbonate tube and
emerges from the aerator in the form of thousands of micro bubbles.
These bubbles flow to the top of the fuel where they burst forming
a vapor cloud composed of alcohol, water, and four other oxygen
bearing chemicals. The same suction that introduced air into the
container now draws the vapor into the carburetor by a means where
it combines with the regular mixture of air and fuel. Under the
terrific heat of combustion, the elements in the fuel release pure
oxygen and steam. These elements slow the combustion process and
causes an increase in volumetric efficiency or burning of the fuel.
Unlike other systems, this auto emission control system has a valve
which increases the volume of vapor as engine vacuum decreases.
This is just the opposite of other systems which cease to function
when they are needed most, such as when it is necessary to
accelerate to pass a car or climb a hill."
4-32
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"The addition of the air-needles makes the system unique. The air-
needles replace the stock air idle adjustment screws. The engineered
orifice allows a jet stream of air to blast the air-fuel mixture in
the carburetor venturi. This air blast further atomize? the fuel in
the mixture and results in increased combustion efficiency and the
lowering of the hydrocarbon and carbon monoxide emissions from the
exhaust "
"Conventional Needles allow quantities of fuel to spill through
the idle aperture like running water (Figure 4-12a). This excess
gasoline accumulates in the cylinders and burns as fire on the
piston. There is far too much fuel to burn completely and most
of the gasoline goes out through the exhaust or is left behind as
dirty carbon deposits..."
"Air Needles force a stream of air to carry the incoming fu,el
(Figure 4-12b). This blast of air agitates, and aerates the over
rich gasoline mixtures. This 'oxidized' mis.t is carried on into
the cylinders to be ignited. The more complete atomization of
fuel results in greater combustion efficiency which means less fuel
consumption, reduced carbon deposits, fewer polluting emissions."
FUEL NOT MIXING
WITH AIR WILL NOT
BURN COMPLETELY
BUT GOES THROUGH
THE ENGINE AND
IS WASTED.
AIREUEL9 OR 10/1
FUEL MIXED
WITH AIR WILL
BURN COMPLETELY
AIR/FUEL 15/1
(a) Standard Needle
(b) Air Injection Needle
Figure 4-12. DEVICE 325/433. AIR NEEDLE SYSTEM COMPARED TO
STANDARD NEEDLE (DEVELOPER DIAGRAM)
In considering this information supplied by the developer, there are two points
that should be clarified:
1. It is not clear how the valve increases the air-vapor flow as engine
vacuum decreases as claimed by the developer. The metering valve pro-
vided with the unit opens at low vacuum, providing an increasing flow with
increasing vacuum to some point in the mid-vacuum range where it reaches
4-33
-------
a maximum flow as determined by the size of the orifice. Higher vacuums,
then, such as on deceleration, allow the maximum flow rate.
2. A properly adjusted carburetor will provide an air-fuel mixture at idle
in the range at 12 to 1 or 13 to 1 rather than the 9 to 1 or 10 to 1
stated by the manufacturer.
4.1.4.3 Performance Characteristics
Tests on Device 325/433 were performed for the developer on this device by Auto-
motive Testing Laboratories. A summary of the results for seven cars is presented
in Table 4-16 from information supplied by the developer.
Table 4-16. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD
EMISSION TEST RESULTS PROVIDED BY DEVELOPER (1)
VEHICLE
MODEL
1960 Valiant
1960 Valiant
1965 Nova
1965 Nova
1964 Valiant
1964 Valiant
1964 Dart
1964 Dart
1965 Mustang
1965 Mustang
1965 Ford
1965 Ford
1965 Ford
1965 Ford
CID
170
170
194
194
225
225
273
273
289
289
352
352
390
390
CONTROL SYSTEM
Without device
With device
Without device
With device
Without device
With device
Without device
With device
Without device
With device
Without device
With device
Without device
With device
HOT CYCLE EMISSIONS
TEST
A-288
A-289
A-239
A-252
A- 240
A-243
A-216
A-245
A-289
A-281
A-228
A-247
A-249
A-250
CO (%)
6.43
5.95
3.22
1.35
1.74
0.97
1.88
1.19
4.36
2.51
1.61
1.38
2.73
0.89
HC (PPM)
608
444
404
244
387
390
517
385
804
525
308
206
431
240
NOx (PPM)
342
324
665
796
1117
1109
1208
975
702
563
931
569
1166
1107
(1) Emission results obtained by California 7-cycle, 7-mode test procedure
(Reference 115), hot cycles only.
4-34
-------
For these seven vehicles, average reductions of exhaust emissions after installa-
tion and adjustment of the system are shown in Table 4-17.
Table 4-17. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD
AVERAGE PERCENTAGE EMISSION REDUCTION (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT
HC (PPM)
494
347
29.7
CO (%)
3.14
2.03
32.1
NOx (PPM)
876
791
10.0
(1) Average of seven hot-cycle tests reported in Table 4-16.
These results indicate that the device may be effective in controlling HC and CO.
Further testing for cold and hot start conditions would be required to verify the
overall effectiveness of the device.
4.1.4.4 Reliability.
The developer reported that approximately 10,000 production units of Device 325/433
have been installed and have accumulated 5 million vehicle miles, with no failure
reported. Based on an examination of the device, it should exceed 50,000 MMBTF,
if installed and maintained according to specification.
4.1.4.5 Maintainability
The developer specified maintenance requirements as follows:
1. The vapor injector must be checked and serviced regularly for
maximum efficiency.
2. The device should receive the maintenance attention as given other
vehicle components.
3. The fluid level should be checked regularly and serviced every
90 days or 2,500 miles, whichever occurs first. The unit should be
cleaned and filled with new fluid, and the air filter checked and
changed when dirty.
Additional maintenance would include checking the air needle bleed hole by using
a wire-type feeler gauge or other appropriate probe, and a visual inspection of
the vapor injection system to assure that the unit is aerating and that all connec-
tions are secure. It is estimated that the maintenance required can be performed
in less than 30 minutes.
4-35
-------
4.1.4.6 Driveability and Safety
The developer reported that there are no adverse effects from the device on vehicle
driveability. There appear to be no safety hazards. The device has indicated no
problems over 5 million vehicle miles.
4.1.4.7 Installation Description
The installation of Device 325/433 consists in mounting the alcohol-water reservoir
in the engine compartment in a near vertical position, installing an adapter plate
between the carburetor and intake manifold, replacing the idle adjustment screws
with special screws, installing the metering valve in the PCV line, connecting the
hoses, and filling the reservoir with the special fluid.
Adjustment consists in setting the engine idle to factory specifications, and
retarding the spark by 2 or 3 degrees if necessary. The developer states that
to obtain the best results from the vapor injector, installation should be accom-
plished by a "certified service man or engine mechanic."
Table 4-18 summarizes the installation requirements. The developer estimated that
the installation of the system would take about one hour. Installation can be
accomplished in a normally equipped repair shop by the average mechanic.
4.1.4.8 Initial and Recurring Costs
According to the developer, the cost of the device installation is $40. Table 4-19
summarizes the estimated total installation costs for this device. From the in-
formation available, it is estimated that the initial cost of this device, including
material, would be $55.62.
4.1.4.9 Feasibility Summary
This device represents a twofold approach to achieving reduced emissions of CO and
HC by air and vapor dilution of the air-fuel mixture. Further testing would appear
to be required to determine the relative contribution of each approach to emission
control over a range of vehicles and test conditions, as well as to determine the
overall cost effectiveness of these related approaches.
4-36
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Table 4-18. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Drill or punch holes for reservoir mounting
bracket, using sheet metal screws provided
in kit. Reservoir is to be mounted in the
engine compartment in a near vertical
position, preferably away from exhaust
manifold.
2. Remove plug from top of reservoir and fill
with special fluid, replace plug.
3. Install reservoir in mounting bracket.
4. Attach hose to outlet in reservoir.
5. Install metering valve in vacuum line
between PCV valve and intake manifold.
6. Attach hose from reservoir to metering
va Ive .
7. Remove stock air-idle adjustment screw
and screw in special replacement screw.
8. Start vehicle engine and allow it to warm
up to normal operating temperature.
9. Place the transmission in neutral until
chemical has a smooth boil of bubbles.
Race engine so that during the short
thrusts of power, the solution will not
boil up and be drawn into the outlet tube
as a liquid.
10. Attach a tachometer and set the idle to
factory specifications.
11. Most vehicles can be changed to regular
fuel without further adjustment. It may
be necessary to retard spark by 2 or 3
degrees .
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill
b. Sheet metal screws
c. Mounting bracket
Special fluid
Special fluid
a. Hose
b. Clamp
a. Metering valve
b. Knife
c. Clamps or hand tools
d. Adapter plate
Clamps
Special idle adjust-
ment screw
Tachometer
Engine analyzer
Total Time
TIME
(MIN.)
25
5
3
2
2
2
5
10
6
10
5
1.25 hr
4-37
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Table 4-19. DEVICE 325/433 AIR-VAPOR BLEED TO INTAKE MANIFOLD
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1 . Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Fluid reservoir
b. Metering valve or
adapter plate
c. Special idle
adjustment screw
a. Mounting bracket
b. Sheet metal screws
c. Special fluid
d. Hose and clamps
)
Viable 4-18
)
LABOR HOURS OR
ITEM QUANTITY
1 hr.
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Alcohol-water
mix
Labor
1. Inspect and
service
Alcohol additive
$2.30/refill at
2,500-mile intervals
0.5 hr every 2,500
miles: 10 x $12.50
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
40.00
(Included
in above)
12.50
3.12
$55.62
46.00
125.00
$171.00
$226.62
4-38
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4.1.5 Device 401; Air-Vapor Bleed to Intake Manifold
This device operates on the same air-vapor bleed principle as Device 325/433. De-
vice 401, however, utilizes only the intake manifold as the air-vapor bleed intake
point.
4.1.5.1 Physical Description
Device 401 is called a vapor injector, and consists of an alcohol-water fluid stor-
age bottle with hose connections to the intake manifold. Figure 4-13 shows a typical
system installation. The fluid storage bottle (B) is of 2-quart capacity and is
mounted in the engine compartment away from exhaust heat. It is connected through
hoses (D) to one of the primary vacuum lines. If connected to the PCV line (E) as
shown, the unit must be teed in downstream of the PCV valve. The vapor injector
metering valve (A) is located on the bottle.
AIR INTAKE
Figure 4-13. DEVICE 401 AIR-VAPOR BLEED TO INTAKE MANIFOLD
SYSTEM CONFIGURATION (DEVELOPER DIAGRAM)
4.1.5.2 Functional Description
The vapor injection system operates on the principle of injecting an alcohol-water-
air vapor mixture into the combustion process of the engine to enhance combustion
and the formation of fewer pollutant byproducts. The vapor is typically drawn into
the intake manifold through the PCV inlet downstream of the PCV valve. The metering
valve operates on a low vacuum and supplements the flow or crankcase blowby from the
PCV valve to the manifold with the alcohol-water-air vapor from the fluid storage
bottle. A metering orifice in the valve limits the total flow of vapor.
Flow is achieved in the fluid storage bottle by venting the bottom of the fluid to
atmosphere and drawing a vacuum on the bottle above the fluid level causing the air
4-39
-------
to pass thiough the liquid. The resulting air-vapor mixture is drawn into the PCV
line to the intake manifold, under intake manifold vacuum.
4.1.5.3 Performance Characteristics
The developer provided results of emission tests performed on a 1970 Chevrolet prior
to the retrofit program. These results are summarized in Table 4-20. The device
indicates emission control characteristics similar to the air bleed class. CO re-
duction is average for an air bleed, whereas HC is typical. The increase in NOx
further classifies the device as basically an air bleed type. This increase in NOx
would indicate that not enough fluid enters the intake manifold to have any cooling
effect on combustion temperature.
Table 4-20. DEVICE 401 AIR-VAPOR BLEED TO INTAKE MANIFOLD EMISSION TEST RESULTS
REPORTED BY DEVELOPER
VEHICLE
CONFIGURATION (1)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
1.76
1.33
25.0
CO
23.73
15.63
34.1
NOx
5.64
7.39
-31.0
(1) Results of one set of 7-cycle, 7-mode, cold-start tests performed on
a 1970 Chevrolet with 350-CID engine, with and without the device
installed.
4.1.5.4 Reliability
This device is sufficiently similar to Devices 325 and 433 to estimate that its re-
liability exceeds 50,000 MMBTF.
4.1.5.5 Maintainability
The developer indicates that the 2-quart fluid supply must be replenished at about
two-month intervals, the equivalent of about 2,000 miles. It is estimated that addi-
tion of the fluid and any necessary readjustment of the flow rate valve can be ac-
complished in less than 10 minutes. Two quarts of the fluid costs $2.50.
4.1.5.6 Driveability and Safety
Although driveability data were not provided by the developer, it would appear that
the device would have about the same driveability characteristics as the other air
bleed devices. The device is a production system and thus is apparently in use. No
safety hazards are apparent.
4-40
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4.1.5.7 Installation Description
Installation of Device 401 consists in mounting a fluid reservoir in the engine com-
partment, and connecting a hose from the reservoir to the intake manifold. Adjust-
ment of the device consists in adjusting the flow of air through the air intake valve
on the fuel reservoir with the engine running, until the bubbles breaking the surface
are too numerous to count. Adjustment of the engine consists in setting the ignition
timing and ignition point dwell to factory specifications, and adjusting the engine
idle rpm.
Table 4-21 presents the details of the installation requirements. Installation can
be accomplished in a normally equipped repair shop with an average mechanic skill
level.
Table 4-21. DEVICE 401 AIR-VAPOR BLEED TO INTAKE MANIFOLD INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1.
2.
3.
4.
5.
6.
7.
8.
9.
Make sure car is in sound mechanical condi-
tion; rings, valves, carburetor, vacuum
lines tight, clean air filter, PCV valve
working.
Find vertical place in engine compartment
away from excessive heat and install
mounting bracket for reservoir.
Mount reservoir in bracket and fill with
fluid mixture.
Cut line between PCV valve and intake mani-
fold. Insert T-fitting into this line.
Connect hose from T-fitting to reservoir.
Start engine and adjust the flow of air
through the air intake valve on the
reservoir until the bubbles breaking the
surface are too numerous to count.
Set the dwell on the ignition points at
this time to factory specifications.
Adjust engine idle speed.
Set ignition timing to factory specifications
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
a. Hand tools
b. Mounting bracket
a. Fuel reservoir
b. Fluid
a. Hand tools
b. T-fitting
Hose
Engine analyzer
Engine Analyzer
Engine analyzer
Total Time
TIME
(MIN.)
15
10
5
5
5
5
5
2
8
1 hr
4-41
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4.1.5.8 Initial and Recurring Costs
The developer estimated that the cost of the device would be $30 and the fluid $2.50.
Table 4-22 summarizes the overall costs for this device. From the information avail-
able, it is estimated that the cost for installing this device, including material,
would be $45.50.
4.1.5.9 Feasibility Summary •
Device 401 is basically an air bleed device. The test data provided by the developer
indicates some effectiveness for HC and CO reduction. There appear to be no safety
hazards or reliability problems. The filling of the fluid reservoir with an alcohol-
water mixture every two months or so is the principal recurring cost.
The device appears to be technically feasible as a candidate retrofit device to re-
duce HC and CO, and is available on the automotive accessory market. Whether the
device is as cost effective for a variety of used cars as other less expensive air
bleed devices should be evaluated in further tests of these devices.
Table 4-22. DEVICE 401 AIR-VAPOR BLEED TO INTAKE MANIFOLD
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Fuel reservoir
b. Mounting bracket
c. T-fitting
a. Fluid
b. Hose
Table 4-21
Table 4-21
LABOR HOURS OR
ITEM QUANTITY
0.75 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Refill fluid
reservoir
Refer to paragraph
4.1.5.5
2 quarts every 2,000
miles x $2.50 for
50,000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
30.00
3.00
9.38
3.12
45.50
62.50
62.50
108.00
4-42
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4.1.6 Device 418: Air Bleed to Intake Manifold
This device uses the crankcase blowby return line as the means of introducing addi-
tional air to the intake manifold. This is the same approach to air bleed intake as
used by Device 401, described in the preceding paragraphs. If the vehicle is origi-
nally equipped with a PCV system, it is designed to provide some air ventilation
through the crankcase which tends to lean the carburetor mixture. On the other hand,
the blowby gases which leak past the piston rings are mostly air-fuel mixture, and
when recirculated to the intake manifold, does not change the carburetor air-fuel
ratio appreciably. Only limited evaluation of this approach was possible in the retro-
fit study, as the developer did not respond to the data survey questionnaire. Data
presented below are based on emission tests performed on the device by EPA (Reference 88)
4.1.6.1 Physical Description
Device 418 is small, tubular in shape, and is installed in the PCV line according to
the manufacturer's instructions. The standard PCV valve is left in place.
4.1.6.2 Functional Description
Under high vacuum conditions use of Device 418 results in the bleeding-in of addi-
tional air. In the EPA tests, the flow through the PCV line under high'intake mani-
fold vacuum (12 inches mercury and higher) increased from about 2 cubic feet per
minute without the device, to 4.5 cfm with the device. This was an increase of 125
percent under idle type conditions. At low vacuum (6 to 30 inches of water) PCV flow
with the device installed was restricted up to 45 percent .of normal flow.
4.1.6.3 Performance Characteristics
The device was tested by EPA installed in the PCV line of a 1970 Chevrolet Impala, a
1970 Plymouth Valiant, and a 1963 Ford. The Impala was equipped with an automatic
transmission and a 350-CID engine. The Valiant was equipped with an automatic trans-
mission and a 225-CID engine. The 1963 Ford had a 269-CID engine with automatic
transmission. Indolene 30 was used for testing of the Impala and the Ford while
Indolene Clear was utilized for the Valiant.
Table 4-23 summarizes the results of tests to the 1972 Federal Test Procedure.
For the 1970 Impala, use of the 1972 Federal Test Procedure showed that HC and CO
were reduced, but NOx increased 4 percent. The 1963 Ford.showed a decrease of HC
and CO, and a 35 percent increase in N0x0 The Valiant showed a reduction of 20% for
HC, 48% CO, and 10% for, NOx. ' .
In addition to the emission tests described in the previous section, two other tests
were employed to further evaluate the device. Fuel consumption was measured during
each emission test. The Valiant equipped with the device showed a 9 percent reduc-
tion in fuel consumption during the 1972 Federal Test Procedure evaluations. On
the other hand, the Impala used 7 percent more fuel during 1972 Federal Test Pro-
cedure tests when equipped with this device. The Ford used 4 percent less fuel when
equipped with the device.
4-43
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Table 4-23. DEVICE 418 AIR BLEED TO INTAKE MANIFOLD
MEAN EMISSION TEST RESULTS (REFERENCE 88) (1)
VEHICLE CONFIGURATION
1970 Valiant:
Without Device
With Device
Percent Reduction
1970 Impala:
Without Device
With Device
Percent Reduction
1963 Ford:
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
2.78
2.00
28
4.83
3.79
22
6.56
5.96
10
CO
48.02
25.40
48
48.60
25.26
48
98.19
46.70
52
NOx
6.27
5.62
10
5.2
5.4
-4
3.65
4.94
-35
NUMBER
OF TESTS
6
4
8
3
2
4
(1) Average of results obtained with 1972 Federal Test Procedure (Reference 3)
4.1.6.4 Feasibility Summary
It was not possible to evaluate this device for reliability, maintainability, drive-
ability, and safety, or costs because the necessary data were not available.
Carbon monoxide emissions were substantially reduced by the installation of the de-
vice. Because the device caused additional leaning of the air-fuel mixture, very
lean running vehicles might develop adverse driveability effects with installation
of the device. A sizeable portion of new vehicles currently operate close to the
lean limit of combustion. Although the NOx did not react consistently to the instal-
lation of the device, the increasing NOx emissions from two of the vehicles (Impala
and Ford) appear to be the only adverse effects of the leaning.
Fuel consumption effects ranged from a 9 percent savings to a 7 percent penalty on
the Impala. No conclusion as to the effect of this device on fuel consumption can
be made. Based on the performance of other air bleed devices, Device 418 could be
expected to provide some fuel economy.
Considering the overall test results, Device 418 indicates satisfactory effective-
ness for the control of CO exhaust pollutant, but less significance for control of
HC and none for NOx.
4-44
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4.1.7 Device 458; Air Bleed to Intake Manifold
The sole source of information on this device was an EPA test report (Reference 89).
This device operates on the air-bleed principle by adding a mixture of air and vapor-
ized chemical to the piston blowby gas returning to the intake manifold from the
crankcase. The device connects into the positive-crankcase-ventilation return line.
This type of system hookup is similar to that of Device 401 (paragraph 4.1.5). The
amount of air-vapor mixture added to the piston blowby gas is controlled by amount of
intake manifold vacuum.
The device was tested by EPA as part of its continuing evaluation of retrofit devices
for used cars. The results of these tests are summarized in Table 4-24.
Table 4-24. DEVICE 458 AIR BLEED TO INTAKE MANIFOLD
EMISSION TEST RESULTS (REFERENCE 89) (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
No Fluid (3)
Percent Reduction
POLLUTANT (GM/MI)
HC
2.7
2.8
. -3.7
2.3
14.8
CO
28
26
7
24
14
NOx
3.7
4.0
-8.1
2.7
27.0
NUMBER
OF TESTS
1
2
(1) Average of results using 1970 Federal Test Procedure (Reference 15).
(2) 1968 Ford Falcon with 200-CID, six-cylinder engine and normal trans-
mission; equipped with original air injection pump.
(3) Device hardware hooked up, but no fluid in container.
The EPA report concluded that:
"The effectiveness of the vapor injector device for reducing emis-
sions is apparently a function of the air bled into the manifold.
This results in a leaner air-fuel mixture."
Based on this test program, it would appear that Device 458 has marginal effective-
ness for exhaust emission control even when .used only as an air-bleed system. As
concluded in the EPA report, "equivalent results could be obtained by using a very
lean idle setting."
4-45
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4.1.8 Device 462; Air Bleed to Intake and Exhaust Manifolds
This device appears to operate on the air-bleed principle by allowing filtered air
to be drawn into the piston blowby return line to the intake manifold. The device
also appears to incorporate a rudimentary form of thermal reaction in that it also
allows air to enter the exhaust manifold. These two principles combined constitute
a twofold approach to the control of CO and HC. The intake air bleed decreases the
amount of CO and HC generated- during combustion, and the exhaust air bleed may con-
tinue the oxidation process in the exhaust manifold.
The only information obtained on this device was in an EPA exhaust emission test
report (Reference 90). The following description of the device was provided in that
document:
"The (device) is a two part system containing an 'exhaust scaven-
ger' and a 'crankcase scavenger.' The exhaust scavenger is a pipe
with a one-way valve that is connected to the exhaust through
holes that must be drilled and tapped into the exhaust manifold.
Under any condition of low pressure in the manifold, air will be
drawn through a valve and filter from the engine compartment into
the manifold. The crankcase scavenger is a large diameter tube
containing plates with drilled holes to allow air passage and a
filter. This unit is installed in the positive crankcase venti-
lation (PCV) line with the interior working parts of the PCV re-
moved. This allows an increase in air flow at idle as there is
no idle restriction in the crankcase scavenger as is normally
found in the PCV system. The total effect of this device is to
admit additional air to the manifold, thus providing a leaner
fuel-air mixture to the engine. . . .
"In the Government installation of the (device) the only portion
of the emission control system disconnected was the PCV valve as
required in the instructions. On the vehicle converted. . .
the PCV valve was disconnected and the heat stove that supplies
warm air to the carburetor was cut into to provide clearance
for the device. The effect of this system is unknown but con-
sidered minimal."
Figure 4-14 shows a sketch of the two parts of the overall system, as provided in an
attachment to the EPA report.
The results of emission tests performed by EPA are summarized in Table 4-25. The
EPA report concluded that the emission reduction effectiveness of the device was
minimal, and that equivalent results could be obtained by using a lean idle setting.
The report also said that there were no fuel economy improvements shown for the de-
vice based on the tests performed.
This limited evaluation indicates that Device 462 would be a marginal candidate for
retrofit on used cars to control their exhaust emissions. Further study using de-
tailed device data would be required to evaluate the overall cost effectiveness of
this device as a retrofit emission control.
4-46
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CRANKCASE
DEVICE
INTAKE
.MANIFOLD
(a) Intake Air Bleed
DEVICE
EXHAUST MANIFOLD
(b) Exhaust Air Bleed
Figure 4-14. DEVICE 462 AIR BLEED TO INTAKE AND EXHAUST MANIFOLDS
FUNCTIONAL AND INSTALLATION SCHEMATICS (REFERENCE 90)
4-47
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Table 4-25. DEVICE 462 AIR BLEED TO INTAKE AND EXHAUST MANIFOLDS
MEAN EMISSION TEST RESULTS (REFERENCE 90)
VEHICLE CONFIGURATION
1963 Chevrolet (1)
Without Device
With Device
Percent Reduction
1968 Falcon (2)
Without Device
With Device
Percent Reduction
Weighted Percent Reduction (1) and (2)
1968 Falcon (3)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
8.8
7.2
18
3.5
3.1
11
24.6
3.0
2.3
23
CO
90
89
1
35
29
17
10.1
29
24
17
NOx
1.8
1.4
22
5.5
6.4
-16
r30
3.9
3.9
0
NUMBER
OF TESTS
HC/CO NOx
8 4
6 3
2
3
2
1
(1) 1963 Chevrolet V-8 with manual transmission, HC and CO average of eight
tests without and six tests with the device installed, and NOx average of
4 tests without and 3 tests with device installed. All tests performed
using the 1972 Federal Test Procedure (Reference 3).
(2) 1968 Ford Falcon with 200-CID sixTcylinder engine and manual transmission,
average of two tests without and three tests with the device installed,
using 1972 procedure.
(3) Same vehicle as (2), average of two tests without and one test with the
device installed, using 1970 Federal Test Procedure (Reference 15).
4-48
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4.2 EXHAUST GAS RECIRCULATION - RETROFIT SUBTYPE 1.2.2
Exhaust gas recirculation (EGR) systems are intended to reduce nitrogen oxide emis-
sions by recirculating a portion of the exhaust gases to the combustion chamber.
Recirculated exhaust gas provides an essentially inert dilutant in the fuel-air
mixture entering the combustion chamber. This increases the heat capacity of the
gas mixture, decreasing combustion temperature with corresponding decrease in the
formation of nitrogen oxides (Reference 116). The product of exhaust gas flow rate
and specific heat have been found to correlate with NOx reduction (Reference 117).
Recirculated exhaust gas is typically ported through a line between a bleed tap in
the exhaust system and an injection port in the intake manifold. The amount of
exhaust gas recirculated to the induction system is a function of the line resis-
tance and differential pressure between the exhaust bleed port and intake injection
port. The amount of exhaust gas recirculated may be controlled by inserting a
metering orifice in the connecting line. Since the amount of gas recirculated also
depends on pressure differential between the exhaust system and intake port, the
amount of recirculated gas may also vary with operating mode. For example, a de-
crease in manifold vacuum, as during an accelerating mode, could cause a corres-
ponding decrease in the portion of recirculated exhaust gas.
Exhaust gas recirculation either as a single approach or combined with a control
approach for HC and CO offers potential for NOx control. A problem of concern is
the compatibility of the exhaust gas recirculation approach with companion control
approaches for HC and CO emissions. The recirculation systems must be designed to
operate in exhaust gas environment without performance degradation either in itself
or other engine components as a result of exhaust gas deposits and contamination.
An example of an apparently compatible combination for EGR is that represented by
Device 57, Air Bleed with EGR and Vacuum Advance Disconnect, described in paragraph
4.1.3. How much an air bleed may negate the NOx inhibition of EGR is a question
not yet answered.
Among the four devices discussed in this section (refer to Table 4-1), Devices 10,
246, and 294 represent combination approaches in which EGR is the principal device
cost factor. Devices 10 and 246 combine EGR with vacuum advance disconnect, and
Device 294 combines EGR with an experimental carburetor. Device 245 was the only
retrofit system found that used EGR as a single approach to emission control, and
does so without external recirculation of the exhaust gas.
Devices 10 and 246 - though similar in approach in combining EGR with vacuum advance
disconnect - operate differently. Device 10 uses vacuum advance disconnect at all
speeds, whereas Device 246 uses it only at idle and below 26 mph, when the EGR sys-
tem is not operative. Both of these devices were tested in the retrofit study
program.
Insufficient data were available on Device 294 to determine its approach to EGR.
4-49
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4.2.1 Device 10; Throttle-Controlled Exhaust Gas Recirculation with Vacuum Advance
Disconnect
This device is a carburetor fuel vaporizer modification that incorporates throttle-
controlled exhaust gas recirculation with vacuum advance disconnect. The device
was tested for emission reduction effectiveness, fuel consumption, and driveability
in the retrofit program. The device has been a candidate for accreditation as a
used car retrofit device in California.(Reference 80).
4.2.1.1 Physical Description
A system installation of Device 10 is shown in Figure 4-15. The device provides
the following emission control techniques:
1. The carburetor inner venturi cluster is replaced with a "vaporizer" which
consists of a tubular insert mounted in the venturi inlet. Fuel is
metered downward through the insert to an injector head. The injector
head contains an array of 20 injector holes through which fuel is injected
laterally in the plane of the venturi throat.(1)
2. An exhaust recirculation line is added which recirculates a small fraction
of exhaust gas from a point upstream of the muffler to a point downstream
of the carburetor throttle plate into the intake manifold. The exhaust
recirculation line is a 3/8-inch tubing. Exhaust gas enters the intake
manifold through a port in an adapter plate mounted between the carburetor
and intake manifold. The adapter plate also includes a control valve which
permits increased exhaust gas recirculation as the throttle setting is
increased. The recirculation valve operates by a ball chain attached to
the throttle linkage. A preset amount of slack in the chain permits small
throttle openings without recirculating exhaust gas. Thus, there is no
recirculation at idle or low speeds. Flow of recirculated gas would be
less at wide open throttle settings due to low manifold pressures, except
that this is compensated for by the opening of the throttle-controlled
butterfly control valve, which increases the flow of exhaust gas.
3. A thermostatic vacuum switch is installed on the radiator return hose and
the distributor vacuum advance line is routed through this switch. Under
normal water temperature conditions the thermostatic vacuum switch closes
the vacuum line between the carburetor and distributor, rendering the
vacuum advance inoperative.
4.2.1.2 Functional Description
Functional characteristics of the emission control system may be summarized as
follows:
1. The varporizer replacing the main fuel discharger nozzle in the venturi
throat provides for more complete and homogeneous mixing of fuel and air.
(1) As noted in paragraph 4.2.1.6, this vaporizer was not included on one of the
cars tested in the retrofit program.
4-50
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Figure 4-15.
DEVICE 10 THROTTLE-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
SYSTEM CONFIGURATION
2. The exhaust gas recirculation system between exhaust and intake manifolds
lowers combustion temperatures and resulting NOx emission reduction at mid-
to wide-open-throttle positions.
3. The distributor vacuum advance is normally disconnected to provide reduced
combustion residence time. This is intended to provide reduced burning
time in the cylinders and reduction in the formation of NOx emissions.
This also promotes additional burning of hydrocarbons in the exhaust mani-
fold. If the engine begins overheating as a result of the disconnected
vacuum advance, the thermostatic switch located in the radiator return
hose opens and restores the vacuum advance to normal operation.
4.2.1.3 Performance Characteristics
Table 4-26 presents emission reduction characteristics of Device 10 based on data
measured in the retrofit test program. The device showed an average emission reduc-
tion of 37 percent for HC, 29 percent for CO, and 54 percent for NOx. Additional
emission reduction data were reported in Reference 80. This report showed a 50-car
average emission reduction of 36 percent for HC, -0.5 percent (increase) for CO,
and 56 percent for NOx. Tests performed in the retrofit study were in accordance
with the 1972 Federal Test Procedure CVS mass measurements (Reference 3) while the
tests performed in the Reference 80 program were in accordance with 7-mode, 7-cycle
concentration measurement procedures (Reference 115).
4-51
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Table 4-26. DEVICE 10 THROTTLE-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
EMISSION REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE /CID
1965 Chev 327
Without Device
With Device
Percent Reduction
1961 Chev 283
Without Device
With Device
Percent Reduction
Mean Percent
Reduction
ANAHEIM TEST RESULTS
'
POLLUTANT . GRAMS /MILE
HC
9.17
4.96
45.9
6.33
4.59
27.5
36.7
CO
66.67
40.69
39.0
89.96
73.50
18.3
28.7
NOx
3.46
1.54
55.5
2.19
1.06
51.6
53.6
FUEL
MILES/
GALLON
13.22
13.70
-4.0
12.54
12.15
3.1
-0.5
(1) Emission results obtained by Olson Laboratories in tests performed
under Contract 68-04-0038 using 1972 Federal Test Procedure (Refer-
ence 3). Fuel consumption was measured during these tests.
4.2.1.4 Reliability
Evaluation of the test results in the referenced Northrop report indicate that the
system has a potential reliability in excess of 50,000 mean-miles-before-total-fail-
ure provided certain deficiencies are corrected. Of particular note were the fail-
ures of the exhaust gas recirculation valves which were prone to stick in the open
position. This was attributed to the buildup of carbon deposits inside the valve.
The thermostatic override control for the vacuum advance is another reliability-
critical component. Although no engine (or retrofit system) failures were attrib-
uted to this component, recommendations were made in the Northrop report to provide
greater confidence in the reliability of the device (Reference 80).
4.2.1.5" Maintainability
Assuming that product improvements are made beyond the previously tested configura-
tion, it is anticipated that routine maintenance could be performed within 30
minutes (MTTM) at 12,000-mile intervals (MMBM). This maintenance would consist of
an inspection of lines and fittings and cleaning of the EGR valve. Also the thermo-
static switch should be tested for correct functioning. A means of testing this
switch should be incorporated integral to the switch.
4-52
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4.2.1.6 Driveability and Safety
During the retrofit study, this device was tested on two cars at the Olson Labora-
tories' Anaheim facility. Tests were run on Retrofit Test Vehicle Cars 4 and 6.
Table 4-27 summarizes the driveability results of these tests. The main effect of
the device appeared to be an increase in 0-60-mph acceleration time.
Table 4-27. DEVICE 10 THROTTLE-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS (l)
CAR NO. 1
U)
CAR NO. 2
U)
CAR NO. 3
(1)
CAR NO. 4
Decreased stall
during cold
start decelera-
tion
Reduced cranking
time during cold
start ; reduced
stall during
cold start idle
Increased from
11.2 to 11.35
No data
CAR NO. 5
(1)
CAR NO. 6
No effect
increased number
of attempts to
start during cole
start; increased
rough idle during
cold start idle;
increased stum-
ble during cold
tion, increased
number of at-
:empts to start
during hot start
Increased from
15.3 to 20.0
Decreased from
24 to 22.5
Average increase of 0.5 percent (reference Table 4-26)
(1) Device 10 was not tested on these vehicles.
The developer included a special carburetor cluster as part of the device installa-
tion on Car 6. It is suspected that this was the cause of the rough idle and
carburetion problems during the test of Car 6 with the device installed. The carbu-
retor cluster was experimental and apparently not perfected. This cluster was not
installed as part of the test on Car 4.
4-53
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No system hazards or safety problems were indicated for this device, provided
that:
1. The exhaust gas recirculation valve does not jam the throttle open. It
appears that the ball chain linkage could preclude this possibility if
the system design and installation is correct for the specific engine/
carburetor configuration.
2. The thermostatic switch does not fail in an unsafe vehicle driving mode;
for example, failure of the switch may or may not result in activating
the distributor vacuum advance mechanism. Inability to provide for the
fail-safe mode could result in catastrophic engine overheating or unexpected
reactivation of vacuum advance.
3. A leak does not occur in the tube from the exhaust manifold to the carbu-
retor adapter plate (fatigue or corrosion). Although this mode of failure
could ultimately result in burned valves, the failure should cause obvious
performance changes prior to engine failure; however, under certain con-
ditions of operation, the vehicle driver and passengers might be exposed to
the possibility of exhaust gas inhalation.
4.2.1.7 Installation Description
The installation of this device consists in installing an adapter plate with EGR
control valve between the carburetor and intake manifold, replacing the inner
venturi in the carburetor with the vaporizer, connecting a recirculating tube from
the exhaust pipe to the adapter plate on the carburetor, and installing a thermo-
static vacuum advance disconnect switch in the radiator return line. The adjustments
required after installation consist in setting the carburetor to new idle rpm values.
Table 4-28 presents the step-by-step installation procedure. Figure 4-15 shows a
typical installation. Installation can be accomplished in a normally equipped auto-
mobile repair shop with normal skills.
4.2.1.8 Initial and Recurring Costs
The developer stated that the system can be installed by an average mechanic in
about one hour, and should retail for under $65.00. It is estimated that the instal-
lation cost, including material, would be $70.62.
Table 4-29 summarizes costs for this device.
4.2.1.9 Feasibility Summary
The recent California evaluation of Device 10, involving installation and evaluation
of this device on 50 uncontrolled cars, may be summarized as follows: (Reference 80).
1. Emissions: 50-vehicle average percentage reduction (7-cycle, 7-mode con-
centration measurement test procedure):
HC CO .-:NOx
36% -0.5% 56%
(increase)
4-54
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Table 4-28. DEVICE 10 THROTTLE-CONTROLLED EGR WITH VACUUM ADVANCE
DISCONNECT INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove carburetor and studs from"
intake manifold
2. Install longer studs in intake manifolc
3. Install adapter plate over studs or
intake manifold
4. Disassemble carburetor and remove
inner venturi
5. Install vaporizer in place of inner
venturi and reassemble carburetor
6. Install carburetor with adapter plate
between carburetor and intake manifold
7. Burn hole in exhaust pipe before
muffler and weld in connection for
recirculating tube
8. Connect recirculating tube to recircu-
lation control valve, which is connect-
ed to adapter plate
9, Connect linkage from recirculation
control valve to throttle linkage
10. Install thermostatic vacuum switch
in radiator hose
I], Connect thermostatic vacuum switch to
intake manifold and to vacuum advance
on distributor
12, Adjust throttle to give 600-rpm curb
idle for automatic transmissions and
700-rpm idle in neutral for manual
transmissions
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
a. Hand tools
b. Studs
Adapter plate
hand tools
a. hand tools
b. Vaporizer
Hand tools
Ox/acetylene welder
connection
Recirculating tube
hand tools
hand tools
hand tools
a. Tachometer
b. hand tools
Total Time
TIME
(MEN.)
12
4
2
3
3
6
15
1
2
10
2
15
1.25 hr
4-55
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Table 4-29. DEVICE 10 THROTTLE-CONTROLLED EGR WITH VACUUM ADVANCE
DISCONNECT INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
r
• i
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Adapter plate
b. APC vaporizer
c. Recirculating tube
d. Thermos tatic
vacuum switch
a. Studs for intake
manifold
b. Pipe connector
Table 4-28
LABOR HOURS OR
ITEM QUANTITY
1 hr
0.25 hr
COST
(DOLLARS)
55.00
(Included
in above)
12.50
3.12
Total Initial Cost $70.62
50,000-Mile
Recurring Cost:
Material
1. Fuel
Labor
1. Inspection
Note: The 0.5 percent fuel savings indi-
cated for this device is considered
to be of marginal significance
considering the possibility of
experimental error.
Paragraph 4.2.1.5
Four 0.5 hr.
inspections @ 12,000-
mile intervals x
$12.50 per hr
Total Recurring Cost
TOTAL COSTS
1
25.00
$25.00
$95.62
4-56
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2. Installation: Average cost ofvinstallation by California Class A garages,
$21.32.
3. Driveability: 60 percent of car owners reported worse driving character-
istics. 40 percent reported no change or improvement.
4. Reliability: Failure prone exhaust recirculation valve correctable by
redesign.
Tests performed in the retrofit study indicated effective reduction of all three
pollutants by use of the device under the rigorous 1972 Federal Test Procedure.
In reviewing the information available on this device, it appears that all defi-
ciencies to date have been diagnosed as correctable. The relatively insignificant
reduction in CO emission in the California evaluation was attributed to lack of
idle mixture adjustment procedures in the installation instructions. Most drive-
ability complaints were believed correctable if road testing is made part of the
installation procedure.
In summary, this device has undergone sufficient development and evaluation as a
retrofit device to identify a majority of its potential shortcomings, all of which
appear correctable. Its performance indicates it to be a technically feasible
candidate for retrofit use.
4-57
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4.2.2 Device 245: Variable Camshaft Timing
Device 245 was one of 11 devices tested in the retrofit study program. This device
varies camshaft timing from fully advanced at idle and low speeds, to a fully
retarded condition at high engine speed. The original purpose of this device was
to maximize engine torque over the engine operating range. However, variable cam-
shaft timing is currently being studied as an alternative means of exhaust gas
recirculation. The concept is to change the closing or opening time of the exhaust
valve in relation to the piston top-dead-center time, so that some of the exhaust
gas is trapped in the cylinder. This constitutes another form of exhaust gas recir-
culation (Reference 87).
4.2.2.1 Physical Description
Device 245, shown in Figure 4-16, is a three-piece cam timing gear. The cam is
connected to the gear through an adjustment bar. The bar rotates within the
sprocket gear, and the two are connected by means of a torsion spring. The variable
cam action is provided through the torsion spring.
The device replaces the conventional timing gear through which the camshaft is
driven. During installation, the camshaft is set at a full advance position with
respect to the crankshaft by adjusting the right-hand or full advance set screw.
This causes a slight preload in the torsional spring. The left-hand screw is then
set to provide a stop at the desired full retard position.
CAM
TORSION
SPRING
ADJUSTMENT
TORSION
, SPRING
CAM
TIMING
ADJUSTMENT
(a) Front View
(b) Side View
Figure 4-16. DEVICE 245 VARIABLE CAMSHAFT TIMING GEAR
4-58
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4.2.2.2 Functional Description
The objective of the variable cam device is to provide full advance valve timing
at low engine speed, and full retard timing at high speeds. The resulting change
in exhaust valve closing traps some of the exhaust gas in the cylinder. The trapped
gas lowers the temperature of the next combustion event and inhibits NOx formation.
Torque required to drive the camshaft is transmitted through the sprocket gear and
torsional spring to the camshaft. Transmission of high torques through the torsion
spring causes the spring to deflect such that the camshaft rotates to a retarded
position with respect to the sprocket gear. One degree of rotation with respect to
the camshaft sprocket represents two degrees of retardation with respect to crank-
shaft or piston position.
At low or idle speeds relatively low torque is required to drive the camshaft and
little or no rotational deflection of the camshaft relative to the sprocket gear
occurs. As engine speed increases, more torque is necessary to drive the camshaft.
Cause of the increased torque requirement is increased frictional losses between
cam lobes and lifters, rocker arms, spring surge, and exhaust valve opening against
high cylinder pressures. Transmittal of increased torque at high speeds causes
deflection of the torsion spring and rotation of the camshaft with respect to the
driving sprocket gear, resulting in a retardation of the valve timing. The dis-
tributor shaft is gear driven off the camshaft, so that retardation of the ignition
spark also occurs as engine speed increases.
The variable cam device permits the following valve timing control settings:
1. Degree of advancement at idle or low speed may be adjusted by
crankshaft timing gear and variable cam sprocket at the time
of installation.
2. Speed at which the cam begins to retard may be adjusted by the
preload setting on the torsional spring during installation.
3. Rate of retardation with increased speed may be varied by
varying the spring constant. This would probably require
use of interchangeable springs if this parameter is found
to be a significant design variable between engines.
4f Limit settings on degree of retardation may be adjusted with
set screws at time of installation.
4.2.2.3 Performance Characteristics
Table 4-30 summarizes tests performed with Device 245 installed on one vehicle
during the retrofit study test program. These data showed a decrease only in NOx
emissions with a large accompanying increase in CO and HC emission levels.
4-59
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Table 4-30. DEVICE 245 VARIABLE CAMSHAFT EMISSION REDUCTION AND
FUEL CONSUMPTION PERFORMANCE
VEHICLE
YEAR/MAKE/CID
1961 Chevrolet 283
Without Device
With Device
Percent Reduction
ANAHEIM TEST RESULTS (1)
POLLUTANT GRAMS /MILE
HC
4.54
6.17
-35.9
CO
70.78
89.83
-26.9
NOx
2.39
1.89
20.9
FUEL
MILES/
GALLON
16.8
15.1
10.1
(1) Emission results obtained by Olson Laboratories in one set of tests
performed under Contract 68-04-0038 using 1972 Federal Test Procedure
(Reference 3). Fuel consumption was measured during these tests.
For comparison with Device 245 emission control performance, Table 4-31 presents
a summary of emission test data reported by HEW/NAPCA in Reference 91. The report
presented results of several tests on a device which included ignition and carbu-
retion modifications along with variable camshaft timing. In these tests, the 1962
Chevrolet Biscayne with 283 CID engine was run (1) with no variable cam, distribu-
tor vacuum advance connected, and stock carburetor; and (2) with variable cam, dis-
tributor advance disconnected, and a lean carburetor.
4.2.2.4 Reliability
The developer claimed "unlimited" reliability, based upon over 5,000 units having
been distributed to dealers and information reported back from users. The devel-
oper also claimed approvals for the device from the American Hot Rod Association
and the National Hot Rod Association. Additional tests of the device on high-
performance vehicles have been reported in the automotive magazines "Car Craft,"
August 1968 issue, and "Popular Hot Rodding," January 1968 issue.
(2) Additional tests were performed by HEW/NAPCA on another variable camshaft
system as reported in Reference 92. This device used a vacuum diaphragm and
electrical circuits to control cam timing. The device is described in Refer-
ence 93. The tests showed effective reduction of NOx, and the report con-
cluded that variable cam timing could have a beneficial effect on NOx without
increasing CO or HC. Comparing 1970 Federal Test Procedure data for variable
cam timing and conventional exhaust gas recirculation showed the former to
be 50 percent more effective. Three engine camshaft approaches to NOx
reduction were investigated as reported in Reference 118. NOx levels of 1.2-
2.0 gm/mi were attained using the 1970 Federal Test Procedure.
4-60
-------
Table 4-31. COMPARATIVE EMISSION TEST RESULTS FOR A DEVICE TESTED
BY EPA WITH VARIABLE CAMSHAFT TIMING, VACUUM ADVANCE DISCONNECT
AND LEAN CARBURETION (REFERENCE 91) (1)
VEHICLE
CONFIGURATION (2) '
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
12.9
5.5
57
CO
123
61
50
NOx
3.2
1.7
47
(1) Emission results obtained using CVS measurements during nine repeat
cycles of the 1970 Federal Test Procedure (Reference 16). One test
with and without device.
(2) 1962 Chevrolet Biscayne with 283-CID engine.
The available data and examination of the substantial construction of the device
indicate that its reliability should substantially exceed 50,000 miles, if it is
installed in accordance with the developer's instructions. Accordingly, an MMBTF
of 75,000 miles is estimated. This reliability estimate would not be applicable to
vehicles which are used mostly for racing or similar activities.
No partial failure mode was identified other than a broken spring, which is dis-
cussed more fully in paragraph 4.2.2.6. Breakage of the spring is a remote possi-
bility and was not considered to constitute a partial failure mode.
4.2.2.5 Maintainability
The additional vehicle maintenance required as a result of a Device 245 installation
would possibly consist in checking the ignition timing and dwell at 25,000 miles
(MMBM). Mean-time-to-maintain (MTTM) for this activity would be about 0.5 hour.
4.2.2.6 Driveability and Safety
During the retrofit study, tests were run on Car 6 both with and without the device
installed. Table 4-32 summarizes the driveability results of these tests.
During the installation of the device, the developer retarded the ignition timing
as part of his standard procedure. It is believed that the ignition timing may
have been retarded too far and that the driveability problems encountered were
caused by this factor rather than by the device. Improvement of the installation
procedure for ignition timing might produce better driveability results.
An increase in fuel consumption was recorded during the emission tests. (Table 4-3U).
The manufacturer claimed that the device has no failure modes, because breakage of
the torsion spring would only result in full spark retard, even at low rpm. How-
ever, this could result in engine overheating.
4-61
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Table 4-32. DEVICE 245 DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICH
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD \ 1965 PLY.
289 CID 1 318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS (l)
CAR NO. 1
(1)
CAR NO. 2
(1)
CAR NO. 3
(1)
CAR NO. 4
(1)
CAR NO. 5
(1)
CAR NO. 6
No efi'ect
Decreased stall
during cold
start idle; In-
creased stretch-
iness and stunnle
during cold
start accelera-
tion; increased
stretchiness
during hot start
acceleration
Increased from
17-3 to 23-9
Decreased from
23-1 to 21.9
Average decrease of 10.1 percent (reference Table 4-30)
(1) Device No. 245 was not tested on these vehicles.
1
Depending upon the internal configuration within the timing gear cover, a broken
spring might become lodged between the timing gear and chain, resulting in catas-
trophic engine failure under hazardous circumstances. As a minimum, a broken
spring could result in poor low speed performance; and, probably, in enough noise
to provide adequate warning to the vehicle operator to avoid or minimize engine
damage. No other potential hazards are indicated.
4.2.2.7 Installation Description
A typical installation of Device 245 is shown in Figure 4-17. The installation con-
sists in replacing the conventional cam timing sprocket with a Device 245 sprocket.
The device is adjusted by setting the proper spring preload on the sprocket. Ad-
justment of the engine consists in testing to verify that at least a 0.090-inch
clearance exists between each piston and valve (fully open), and adjusting distribu-
tor ignition timing for maximum output at about 3,500 rpm.
4-62
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(a) Torsion Spring Adjustment
(b) General Installation
Figure 4-17. DEVICE 245 VARIABLE CAMSHAFT INSTALLATION
Table 4-33 itemizes the installation requirements. This table is derived from the
installation instructions contained in a Device 245 kit for Oldsmobile V-8 engines
(330, 350, 400, 425, and 455 CID).
The developer estimated one to two hours labor for installation and a retail cost
of material of $40 to $50. Installation can be accomplished in normally equipped
repair shop by the average mechanic. From the information available, it is esti-
mated that the total cost of this installation, including material, would be from
$68.12 to $78.12.
4.2.2.8 Initial and Recurring Costs
Table 4-34 itemizes the 50,000-mile service life costs for the device. Although
there are minimal maintenance requirements, the indicated increase in fuel consump-
tion could increase fuel costs about $28.00 per year.
4.2.2.9 Feasibility Summary
The evaluation of Device 245 as a retrofit method for used-car emission control
should consider that the device is basically an NOx control. Thus any application
of the device for emission control purposes would have to be limited to those air
quality control requirements in which NOx is the principal pollutant. The alterna-
tive would be to combine Device 245 with other retrofit methods for control of two
or all of the principal pollutants. The Reference 91 emission test data indicate
the benefit of such combinations, although the variable cam timing approach tested
by EPA was not identical to Device 245 (refer to Table 4-31). However, the cost
of combining devices may be too high for the effectiveness gained in emission
reduction.
Further testing of Device 245 would be required to establish its NOx control effec-
tiveness for a variety of used cars, as well as its driveability and impact on fuel
consumption.
4-63
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Table 4-33. DEVICE 245 VARIABLE CAMSHAFT TIMING
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
1. Before installation, note ignition
timing with engine about 3,500 rpm
using strobe timing light. Timing
should be the same after installa-
tion.
2. Remove fan, water pump, belts,
crankshaft pulley and other inter-
ference as necessary to get at
timing chain cover.
3. Remove timing chain cover and turn
engine over so sprocket timing
marks are aligned.
4. Remove center bolt, fuel pump
eccentric, and present cam sprocket
(fuel pump eccentric will be
reused).
5. Remove spring adjusting eccentric
from Varicam sprocket.
6. Hold sprocket in place with timing
mark aligned. (If it does not
match the chain, get a new chain
and crank sprocket to match the
Varicam sprocket).
7. Push faceplate in place
8. Hold fuel pump eccentric in place
with tab in dowel pinhole.
9. Insert special locking center bolt
and tighten to a little less than
normal.
10. Hand rotate engine a little in
both directions. Loosen center
bolt just enough to allow faceplate
to move in relation to sprocket.
a. Tachometer
b. Strobe timing light
Hand tools
40
Hand tools
Hand tools
a. Hand tools
b. Sprocket
None
None
None
a. Hand tools
b. Special locking center
bolt
Hand tools
4-64
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Table 4-33. DEVICE 245 VARIABLE CAMSHAFT TIMING
INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
11. Check each cylinder for clear-
ance between piston and each
valve of at least 0.090 inch.
12. Adjust spring preload on sprocket.
13. Insert thrust button into center
of bolt.
14. Check clearance between chain cover
and thrust button, and chain cover
and fuel pump eccentric.
15. Install chain cover. Check instal-
lation for any interference by
turning over engine by hand.
16. Reassemble engine
17. Adjust distributor for maximum
output at about 3,500 rpm by
tachometer or dynamometer
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools
Thrust button
a. Metal straightedge
b. Feeler gauges
Hand tools
Hand tools
Tachometer
Total Time
TIME
(KEN.)
6
1
1
3
6
45
15
2.25 hr
4-65
-------
Table 4-34. DEVICE 245 VARIABLE CAMSHAFT TIMING INITIAL AND
RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
50,000-Mile
Recurring Cost:
Material
1 . Fuel
Labor
1. Inspection
DESCRIPTION
Sprocket
Special locking
center bolt
thrust button
Table 4-33
LABOR HOURS OR
ITEM QUANTITY
2 hr
0.25 hr
Total Initial Cost
Average fuel increase
of 10.1 percent
(Table 4-32)
Paragraph 4.2.2.5
404-gal fuel increase
x $0.35 per gallon
over 50,000 miles
CD
0.5 hr/25,000
miles @ $12.50
per hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
40.00-50.00
(Included in
above)
25.00
3.12
68.12-$78.12
141.40
12.50
153.90
232.02
(1) Based on an assumed national average of 10,000 miles per year at ,
J
4-66
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4.2.3 Device 246: Speed-Controlled Exhaust Gas Recirculation with Vacuum Advance
Disconnect
This device approaches the control of NOx by means of a speed-controlled exhaust
gas recirculation (EGR) system. This is combined with disconnect of the distribu-
tor vacuum advance for further control of NOx and control of HC. The speed con-
trol allows about 15 percent of the exhaust gas to be recirculated to the intake
manifold whenever the vehicle speed exceeds 26 mph. The spaed control shuts off
recirculation whenever the speed drops below approximately 12 mph. A deceleration
switch is also provided to stop recirculation whenever the accelerator pedal is
completely released. The deceleration switch also disconnects the distributor
vacuum advance when the accelerator pedal is released..
The distributor vacuum advance unit is connected to the recirculation system such
that the vacuum advance operates during exhaust gas recirculation at speeds above
26 mph. The vacuum advance is disconnected when exhaust gas recirculation is ter-
minated at low speed by the speed or acceleration pedal controls. Thus the device
apparently is designed to control NOx by EGR at speeds above idle and by vacuum
advance disconnect at idle.
Approximately 9 prototype units have been made by the developer and 90 are scheduled
for completion by mid-April 1972. The device was one of four retrofit devices sub-
jected to extensive emissions and driveability tests during the retrofit study, and
also was subjected to a 25,000-mile durability test. The device also has been
tested by EPA, as reported in Reference 94.
4.2.3.1 Physical Characteristics
Principal components of the exhaust gas recirculation system are shown in Figure
4-18. The exhaust pipe bleed adapter connects to the vehicle exhaust header as
close to the exhaust manifold as possible. The EGR valve connects to the exhaust
adapter and the EGR tube is connected between the valve and the intake adapter
between the carburetor and the intake manifold.
The solenoid valve is interconnected in the vacuum advance tube between the dis-
tributor and the intake manifold, and to the EGR valve. The speed switch and cable
are connected to the speedometer tap on the transmission and to the EGR valve.
The solenoid valve is connected to the speed switch electrically.
4.2.3.2 Functional Characteristics
The vehicle speed is sensed by the speed switch attached to the transmission
through a speedometer cable. When the vehicle speed reaches 26 mph, the speed
switch opens, deenergizing the solenoid actuated valve. Below 26 mph and at idle,
the solenoid valve is energized and held closed preventing both recirculation and
vacuum advance.
Figure 4-19 shows a functional schematic of the system. When the solenoid valve
opens at 26 mph, it ports vacuum to the EGR valve and to the distributor vacuum
advance. Only a small amount of vacuum, approximately 1.5 inches of mercury, is
required to activate the EGR valve. Opening of the EGR valve permits exhaust to
recirculate to the intake manifold. Exhaust gas recirculation is controlled to
approximately 15 percent of total exhaust by a metering restrictor located directly
downstream of the poppet seat of the EGR valve.
4-67
-------
SPEED SWITCH AND CABLE
EXHAUST BLEED
ADAPTER
VACUUM ADVANCE
DISCONNECT
SOLENOID VALVE
NOTE: RECIRCULATION TUBE TO INTAKE MANIFOLD IS NOT SHOWN
EGR VALVE
CARBURETOR
EGR ADAPTER
PLATE
BB049
Figure 4-18. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE
DISCONNECT SYSTEM COMPONENTS
IGN. SW. 12 V.D.C.
SPEED SWITCH
DRIVEN BY
SPEEDO CABLE
SNAP ACTION
SWITCH
EXHAUST PIPE
Figure 4-19. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE
DISCONNECT FUNCTIONAL SCHEMATIC (DEVELOPER'S DIAGRAM)
4-68
-------
The vacuum advance is operating only during periods of exhaust gas recirculation,
and is effectively disconnected when exhaust gas is not recirculated at low speed
and upon deceleration from high speed. Below 26 mph, EGR is shut off by a snap.
action switch actuated by the closed throttle pedal. This switch energizes the
solenoid to terminate EGR and vacuum advance whenever the accelerator pedal is
released, regardless of speed.
4.2.3.3 Performance Characteristics
Emission reductions measured in tests of Device 246 during the retrofit study are
summarized in Table 4-35. These test results indicate that the device is mainly
an NOx control system, though some CO reduction was also indicated. Data supplied
by the developer in Table 4-36 indicate that the device was effective in reducing
HC and NOx emissions.
Tests were performed on this device by EPA as summarized in Table 4-37. The
vehicles were tested in single- and double-solenoid configurations. In the latter,
the vacuum advance disconnect and the EGR functions were divided between two sole-
noids. This was to enable separate control of the two methods for test purposes.
The EPA report noted that the tests of the 1963 Chevrolet without the device
installed were made without the carburetor base plate in position, and that this
may account for the substantial reduction in CO.
Based on the overall results summarized in these tables, the device appears to
reduce NOx consistently. Some control of CO also is indicated. HC control appears
to be relatively less significant.
4.2.3.4 Reliability
The basic exhaust gas recirculation (EGR) valve concept appears capable of demon-
strating a reliability in excess of 50,000 mean-miles-before-total-failure with
proper maintenance. Maintenance for this type of valve might be required, includ-
ing replacement of the valve prior to failure from any fatigue failures that might
result from cycle loading. Longevity testing and analysis would be required to
determine the need for such replacement.
There could be some concern for this type of EGR hookup with regard to the possibi-
lity of fatigue failures in the exhaust gas circuit, between the exhaust pipe and
the carburetor adapter plate, resulting from engine induced vibration. Testing would
be required to determine the adequacy of the design for the vibration environment.
The possible problem of vibration-induced fatigue is peculiar to this EGR device be-
cause of the tie-in to the exhaust pipe. The differences in vibration response char-
acteristics between the exhaust pipe and the engine could possibly induce fatigue
failure in the EGR tubing and in the exhaust-pipe-to-tubing connection.
The remaining functional components of the device are high-production items of
established acceptable reliability. It was indicated by the developer that the
speed switch and speedometer cable assembly are installed as standard items in one
line of 1971 vehicles.
4-69
-------
Table 4-35. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCON-
NECT EMISSION REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Chev 194
Without Device
With Device
Percent Reduction
1965 Ford 289
Without Device
With Device
Percent Reduction
1965 Ply 318
Without Device
With Device
Percent Reduction
1965 Chev 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reductior
1961 Chev 283
Without Device
With Device
Percent Reductior
1965 VW 92
Without Device
With Device
Percent Reductior
ANAHEIM TEST RESULTS
POLLUTANT GRAMS/MILE
HC
(2)
(2)
(2)
8.81
6.38
27.6'
6.12
6.96
-13.7
8.66
8.42
2.8
10.88
10.78
0.9
(2)
8.68
(2)
7.79
6.59
15.4
CO
202.99
177.78
12.4
106.46
70.61
33.7
94.73
63.59
32.9
• 59.29
45.40
23.4
163.37
146.60
10.3
85.86
92.98
-8.3
51.78
45.79
11.6
Pooled Mean Per-
centage Reduction (3)
NOx
0.65
0.263
60.0
4.60
2.88
37.4
5.93
2.70
54.5
4.45
2.81
36.9
3.16
. 1-31
58.5
1.46
0.81
44.5
1.57
1.16
26.1
FUEL
MILES/
GALLON
(2)
11.6
(2)
14.2
11.4
20.0
10.0
12.8
-28.0
12.8
11.9
7.0
9.4
10.6
-13.0
10.5
11.6
-11.0
(2)
(2)
(2)
TAYLOR TEST RESULTS
POLLUTANT
HC
. 3.06 3.69
(2) 4.10
(2) -11.1
6.02 3.38
5.52 3.55
8.3 -5.0
3.95 4.70
9.80 3.84
(2) 18.3
7.61 5.33
6.24 2.88
18.0 46.0
8.17 5.27
7.36 3.15
9.9 40.2
5.32
4.82
9.4
GRAMS/MILE
CO
83.54 38.40
(2) 40.00
(2)
-4.2 '
97.62 43.38
40.64 17.00
58.4
(2)
(2)
(2)
60.8
45.56
24.86
45.4
125.34 89.38
85.97 24.29
31.4
72.8
72.41 55.71
50.62 25.95
30.1
53.4
34.11
43.18
-26.6
HC 12.1 CO 30.9
NOx
6.12 3.24
(2) 1.37
(2) 57.7
4.29 • 3.87
2.25 1.62
47.6 58.1
(2) 3.42
(2) 1.51
(2) 55.8
4.12 2.86
2.28 1.45
44.7 49.3
3.42 2.56
2.02 1.50
40.9 41.4
1.75
(2)
(2)
FUEL
MILES/
GALLON
(2) 12.8
(2) 14.5
(2) -13.3
12.7 13.5
14.0 (2)
-10.2 (2)
(2) (2)
(2) (2)
<2> (2)
12.3 11.6
13.0 15.8
-6.0 -36.2
14.8 16.5
14.2 14.5
4.1 12.0
(2)
(2)
(2)
NOx 47.6 Fuel -7
(1) Emission results obtained by Olson Laboratories in tests performed under Contract 68-04-<)0'j8
using 1972 Federal Test Procedure (Reference 3). Fuel consumption was measured during these
tests.
(2) Test data invalid
(3)- Anaheim and Taylor results combined.
4-70
-------
Table 4-36. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
EMISSION TEST RESULTS REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
5.09
3.30
35.2
CO
12.51
11.37
9.1
NOx
9.85
3.06
68.9
NUMBER
' OF TESTS
2
3
(1) Results obtained using 1972 Federal Test Procedure (Reference 3) hot-
start tests.
(2) 1969 Ford Station Wagon with 429-CID engine, 10.5:1 compression ratio,
2-barrel carburetor, and automatic transmission. Indolene 30 test fuel
was used. Dynamometer inertia was 4,500 pounds.
Subject to the qualifications stated above, the exhaust gas recirculation system
reliability is estimated to be on the order of 75,000 MMBTF.
4.2.3.5 Maintainability
The developer recommended cleaning the EGR valve every 6 months. The requirement
for 6-month/6,000-mile (MMBM) cleaning of the EGR valve orifice is.considered a
general estimate, as insufficient data were available to specifically establish
this requirement. At that time it is also recommended that the solenoid vacuum
valve filter be inspected and cleaned or replaced if .necessary. If the production
configuration EGR valve provides ease of accessibility to clean the orifice, it is
estimated the maintenance task could be done within 30 minutes (MTTM).
Specific repair times to remove and replace any failed components would be depend-
ent upon the specific configuration of the vehicle in which the system is installed.
4.2.3.6 Driveability and Safety
Table 4-38 summarizes the driveability results of tests performed on Device 246
during the retrofit program. Car 3 exhibited a tendency toward hesitation possibly
caused by carburetor settings. This problem may or may not be due to the installa-
tion of the device. Car 4 had a tendency toward detonation at all times when the
hot start tests were run. The problem encountered may or may not be due to the
installation of the device.
Gas mileage increased an average 7 percent with the device operating. The developer
in his tests reported inconsistencies in fuel consumption between the 1969 Ford
station wagon, which had increased fuel consumption in all types of driving, and the
4-71
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Table 4-37. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
EMISSION TEST RESULTS REPORTED BY EPA (REFERENCE 94) (1)
VEHICLE
CONFIGURATION
1971 Chevrolet (2)
Without Device
With One Switch
Percent Reduction
With Two Switches
Percent Reduction
1964 Plymouth (3)
Without Device
With One Switch
Percent Reduction
With Two Switches
Percent Reduction
1963 Chevrolet (4)
Without Device
With One Switch
Percent Reduction
POLLUTANT (GM/MI)
HC
3.7
3.0
19
3.2
14
7.5
6.8
10
8.5
-13
8.3
5.6
32
CO
64.3
57.7
10
51.9
19
116.4
109.9
6
103.4
11
113.8
49.1
57
NOx
3.5
2.4
31
1.9
46
3.7
1.3
65
1.1
70
1.4
0.45
68
NUMBER
OF TESTS
2
1
1
1
1
1
1
2
(1) Average of results using 1972 Federal Test Procedure (Reference 3).
(2) 1971 Chevrolet Impala with 400-CID engine, 2-barrel carburetor, and
automatic transmission.
(3) 1964 Plymouth Fury with 318-CID engine, 2-barrel carburetor, and
automatic transmission.
(4) 1963 Chevrolet Impala with 283-CID engine, 2-barrel carburetor, and
manual 3-speed transmission.
1964 Plymouth, which had decreased fuel consumption in composite and country
driving.(1) This variation was attributed by the developer to a possibly lean
setting on the Plymouth vehicle.
(1) Same vehicles as identified in Tables 4-36 and 4-37.
4-72
-------
Table 4-38.
DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60 - 40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60 - 40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
J961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS (1)
CAR NO. 1
No effect
Increased time
to start during
hot start
Increased from
19.0 to 19-3
Increased from
20.5 to 21.?
CAR NO. 2
No effect
Increased stall
during cold
start idle; re-
duced hesita-
tion during
cold start ac-
celerationjre-
duced singing
during hot D
start cruxse.
Increased from
12.2 to 13-7
Increased from
20-2 to 21.7
CAR NO. 3
Decreased stall
during cold
start decelera-
tion
Increased
stumble during
cold start
acceleration.
Decreased from
11*. 2 to 13-3
Increased from
2^.0 to 25-5
CAR NO. 4
No effect
Increased
stumble during
cold start ac-
celeration; in-
creased detona-
tion during hot
start accelera-
tion.
Increased from
11.6 to 12.5
Increased from
20.8 to 23.0
CAR NO. 5
No effect
No effect
Increased from
12.1 to 12.7
Increased from
19-8 to 25.0
CAR NO. 6
(1)
(1)
(1)
(1)
Average increase of 5 percent (reference Table 4-35)
TAYLOR, MICH., DRIVEABILITY TEST RESULTS
CAR NO. 20
Ko effect
Increase in
hesitation on
both cold and
hot starts, and
trace of stumble
on cold start
Increased from
36.2 to 35.?,
I n i'o rwi t ion not
avaHaL.1-2
CAR NO. 8
Showed rough
idle on hot
start during
replicate
test
Increase in
hesitation
for hot and
cold start
tests.
Increased from
11.7 to 13.lt
Decreased from
2-'+.!4 to S2.5
CAR NO. 9
Ho effect
1st device test
chowed increase
in hesitation
and stumble on
cold start. Hot
start increase
in hesitation
and surge. Re-
plicate test
no problems.
Increased from
13.1* to 13-8
Increased from
22.9 to 2'4.3
CAR NO. 10
No effect
Increase in
hesitation
and stumble
during cold
start
Increased from
10.8 to 11.7
Increased from
23. li to 25.5
CAR NO. 11
Rough idle
on 1st test
Driveability
improved
Decreased from
10.1 to 9-8
Decreased from
25- *t to 23.1
CAR NO. 12
No effect
Increase in
stumble on
cold start
(1st test)
Decreased from
15.1* to 1**.7
Increased from
2U.7 to 28.8
Average increase of 8.2 percent (reference Table 4-35)
(1) Device No. 246 was not tested on this vehicle.
4-73
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Two potential hazard areas involving CO leakage were identified in the study of
the particular EGR approach represented by this device. Both can be visually
inspected to avoid the occurrence of an unsafe condition. The two areas are:
1. A leak in the tube from the exhaust pipe to the EGR valve due to
vibration fatigue or corrosion.
2. A leak in the tube from the EGR valve to the carburetor adapter plate
(fatigue or corrosion). (Although this mode of leak could ultimately
result in burned valves, the failure should cause obvious performance
changes prior to engine failure.)
These safety considerations were discussed in terms of system reliability in para-
graph 4.2.3.4.
4.2.3.7 Installation Description
The installation of this device consists in installing the adapter plate between
the carburetor and intake manifold, drilling a hole in the exhaust line between
the exhaust manifold and muffler to install the EGR inlet adapter, connecting a
tubing assembly from exhaust inlet adapter to the vacuum-operated shutoff valve
and thence to the carburetor adapter plate, installing the solenoid vacuum valve,
connecting tubing and wiring, and replacing the speedometer cable with a new
speedometer cable having a speed switch included. The developer estimated 2 hours
labor for installation and $61 as the retail price of material.
Table 4-39 describes the installation requirements. Figures 4-20 and 4-21 show a
typical installation. Installation can be accomplished in a normally equipped
repair shop with average mechanic skills.
4.2.3.8 Initial and Recurring Cost
Table 4-40 itemizes the overall costs for Device 246 installation, operation, and
maintenance. Initial cost of installation was estimated to be $89.12. If the
device provides the fuel economy indicated, half of the initial investment would
be repaid over a 50,000-mile service life.
4.2.3.9 Feasibility Summary
This device is considered technically feasible with respect to emission reduction,
reliability, driveability, and operating costs, for applications requiring NOx
control. Fleet vehicle testing of the device in the retrofit program indicated
that some control of CO also may be provided by the device. Further fleet testing
may be required to resolve the effectiveness of the device for any application
other than NOx control.
Satisfactory driveability was indicated for 4 of the 6 vehicles equipped with this
device. A majority of the components used in this device (speed switch, accelera-
tion switch, solenoid valve) are off-the-shelf components with demonstrated
reliability.
4-74-
-------
Table 4-39. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
1. Remove carburetor and studs from
intake manifold.
2. Install new longer studs in intake
manifold.
3. Install carburetor adapter plate
over new studs on intake manifold.
4. Reinstall carburetor with adapter
plate between carburetor and intake
manifold.
5. Drill hole in exhaust pipe between
exhaust manifold and muffler.
6. Install inlet adapter in hole in
exhaust pipe.
7. Attach tubing assembly from exhaust
inlet adapter to vacuum operated
shut off valve to carburetor adapter
plate.
8. Mount solenoid vacuum valve on fire-
wall in engine component .
9. Disconnect hose from vacuum spark
advance and connect to solenoid
vacuum valve.
.u. Connect hose from solenoid vacuum
valve to vacuum operated shutoff
valve with T-connection in this line,
.1. Connect hose from the connection to
vacuum spark advance .
.2. Remove speedometer cable and install
new speedometer cable with speed
switch included .
Hand tools
a. Hand tools
b. Studs
a. Hand tools
b. Adapter plate
c. Gaskets
Hand tools
Oxyacetyline torch
a . Hand tools
b. Inlet adapter
c . Clamps
a . Tubing clamps
0. Vacuum operated shutoff
valve
a. Electric drill
b. Screws
c. Solenoid vacuum valve
Hose clamps
a. Hose
b. Clamps
c. T-connection
a. Hose
b. Clamps
a. Hand tools
b. Speedometer cable
with speed switch
24
4
12
21
16
15
4-75
-------
Table 4-39. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
13. Connect wire from one side of
solenoid vacuum valve to ground.
14. Connect wire from other side of
solenoid vacuum valve to speed
switch.
15. Connect wire from other side of
speed switch to fuse panel.
16. Start engine and adjust carburetor
for best lean idle setting.
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Electric wire
a. Hand tools
b. Electric wire
a. Hand tools
b. Electric wire
Exhaust analyzer
Total Time
TIME
(MIN.)
2
2
2
15
2.25 hr
4-76
-------
SOLENOID VACUUM VALVE
VACUUM OPERATED
SHUT OFF VALVE
FUSE PANEL
SPEED SWITCH
CARBURETOR
ADAPTOR PLATE
U BOLT CLAMP
INLET ADAPTOR
Figure 4-20. DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
INSTALLATION (DEVELOPER SKETCH)
Figure 4-21.
DEVICE 246 TYPICAL INSTALLATION ON RETROFIT
PROGRAM TEST VEHICLE
4-77
-------
Table 4-40.
DEVICE 246 SPEED-CONTROLLED EGR WITH VACUUM ADVANCE DISCONNECT
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1 . Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Adapter plate
b. Inlet adapter
for exhaust line
c. Vacuum operated
shutoff valve
d. Solenoid vacuum
valve
e. T-connection
f. Speedometer cable
with speed switch
a. Studs for intake
manifold
b. Gaskets V clamps
for exhaust
adapter
c. Metal tubing for
exhaust gas
d. Screws
e. Rubber hose
f. Clamps for hose
g. Electric wire
Table 4-39
LABOR HOURS OR
ITEM QUANTITY
2 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost :
Material
1. Fuel
Labor
1. Inspection
Fuel miles per
gallon increase of
7 percent
Paragraph 4.2.3.5
280-gal. fuel sav-
ings x $0.35/gal.
over 50,000 miles (1)
0.5 hr/6, 000-mile
intervals @ $12.50/hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
61.00
(Included in
above)
25.00
3.12
$89.12
-98.00
50.00
-$48.00
$41.12
(1) Based on an assumed national average of 10,000 miles per year at 12.5 mpg.
4-78
-------
4.2.4. Device 294: Exhaust Gas Recirculation With Carburetor Modification
Although the developer of this device did not respond to the retrofit data survey
questionnaire, emission data were obtained from an EPA test report (Reference 96).
The device apparently consists of an exhaust gas recirculation system in combina-
tion with an experimental carburetor. The EGR should reduce NOx emissions, but
the principles of emission control used in the carburetor are not known.
The results of EPA tests are summarized in Table 4-41. The results shown with the
device operating on a 1970 Chevrolet with 350-CID engine and automatic transmission
are about the same as tests performed on a 1970 Valiant with 225-CID engine and
automatic transmission. For the latter vehicle, HC was 4.5, CO was 83, and NOx
was 3.9 grams per mile, using the same test procedure with the device operating.
Table 4-41. DEVICE 294 EMISSION TEST RESULTS REPORTED BY EPA
(REFERENCE 96) (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
3.8
6.8
-78.9
CO
67
60
10.4
NOx
4.0
2.8
30.0
(1) Results obtained using 1972 Federal Test Procedure (Reference 3) on a
1970 Chevrolet with 350-CID engine and automatic transmission, one test
with and without device installed.
The EPA report noted that the vehicle (with and without the device) did not meet
any of the emission standards for the model-year vehicle. HC was reduced with the
standard carburetor for that model-year of vehicle installed.
The EPA report concluded that more work appears to be necessary to achieve any
emission reduction effectiveness by means of the device. This conclusion appar-
ently was based on the overall effectiveness of the device for control of all three
pollutants against future emission standards. The reduction shown for NOx indi-
cates potential effectiveness for control of that pollutant. Further test would be
required on a range of representative vehicles to verify this effectiveness for
used cars .
4-79
-------
4.3 INTAKE MANIFOLD MODIFICATION - RETROFIT SUBTYPE 1.2.3
This type of retrofit device approaches emission control by some form of modification
to the air induction system. The approaches generally were based on various aids to
improve fuel mixing and vaporization. The concept back of these devices appears to
be that mixing of the air-fuel mixture downstream of the carburetor will enhance
more complete combustion of the mixture and thereby decrease the formation of exhaust
pollutant byproducts.
4.3.1 Device 172; Intake Manifold Modification
This prototype device is an induction system modification wherein conical metering
inserts are mounted between the intake manifold and intake port of each cylinder and
smaller size jets are used in the carburetor. The conical inserts, referred to as
intake "rams" by the developer, are sized to volumetrically equalize the amount of
air-gas mixture flowing into each cylinder. The small end of the conical inserts
protrudes into the manifold space, and this feature is said by the developer to pre-
vent "wet fuel droplets from entering the combustion chamber." The inserts are
patented under Patent No. 3,429,303.
The improved air-fuel diffusion apparently provided by this device permits use of
smaller carburetor primary jets, resulting in fuel lean operation. Limited tests
conducted by the developer indicated that this device may be effective in reducing
HC and CO emissions. An NOx increase was observed in limited cold start tests with
a small decrease in NOx emission observed in hot start tests.
The developer has recently combined an exhaust recirculation system with the induc-
tion system modifications in order to more effectively reduce NOx emissions; however,
since little information was provided on the combination system, only the induction
system modifications are described.(1)
4.3.1.1 Physical Description
This system consists of the following elements:
1. Conical shaped (truncated cone), stainless steel intake "rams" mounted be-
tween the intake manifold and each intake port of the engine.
2. Smaller sized primary jets installed in the carburetor.
The stainless steel intake rams are actually metering orifices sized to equalize the
air-fuel flow between each cylinder. In some engine models all "rams" are of the
same size. Other engine models require one or more different sizes of "rams" on the
cylinders in order to achieve equalized flow. A typical ram insert is illustrated
in Figure 4-22.
The primary carburetor jet modification employs a standard jet configuration with a
smaller diameter metering hole.
(1) The only information provided on the combination EGR system was fuel consumption
data. These aata from the developer indicated an average fuel consumption
decrease of 35 percent.
4-80
-------
4.3.1.2 Functional Description
This device functions to equalize air-fuel charge between cylinders and reduce the
flow of fuel droplets into the cylinders. The improved carburetion is said by the
developer to permit use of smaller primary fuel jets, resulting in fuel-lean
operation..
A set of rams must be flow calibrated for each engine model, because of induction sys-
tem differences between engine models. Sizing of the intake "rams" to successfully
balance or equalize flow is performed by first isolating the cylinder with the low-
est incoming flow rate. This cylinder will have the largest flow opening. Rams
for the other cylinders are then sized smaller to bring the flow of all other cylin-
ders down to the level of the lowest cylinder.
The second function of preventing wet droplets from entering the combustion chamber
is apparently accomplished by the insert's external configuration which is designed
to create a droplet trap at the point where they are inserted into the manifold.
Droplets trapped at this point are in a convective environment which eventually
causes the droplets to vaporize the re-enter the flow stream into the cylinder. It
was not explained by the developer whether this occurs under both cold and hot start
conditions.
IDENTIFICATION TAB
INTAKE RAM
DROPLET TRAP
INTAKE MANIFOLD
GASKET
TO CYLINDER
Figure 4-22. DEVICE 172 INTAKE MANIFOLD MODIFICATION (DEVELOPER SKETCH)
4-81
-------
4.3.1.3 Performance Characteristics
Table 4-42 summarizes the emission performance characteristics of Device 172 based
on information supplied by the developer. Emission tests conducted under HEW Con-
track CPA 70-51 NAPCA are summarized in Table 4-43. For the latter tests the car-
buretor was modified to incorporate lean main jets and an undefined camshaft revi-
sion was made.
Examination of the Table 4-42 emission data supplied by the developer indicates
that the conical inserts are effective in reducing HC and CO emissions. NOx emis-
sions are increased. Tfce Table 4-43 EPA test data indicates some HC increase with
no CO reduction. NOx was reduced 27%.
Table 4-42. DEVICE 172 INTAKE MANIFOLD MODIFICATION EMISSION TEST RESULTS
REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
2.33
1.61
30.9
CO
52.14
16.80
67.78
NOx
6.10
6.67
-9.34
(1) Results obtained using 1970 Federal Test Procedure (Reference 15).
One test with and without conical inserts installed in intake mani-
fold. No engine modifications or adjustments other than the inserts
were made. Carburetor jets were standard for the vehicle tested.
(2) 1970 Plymouth Valiant with 225-CID 6-cylinder engine and automatic
transmission (approximately 10,000 miles indicated on the odometer).
Table 4-43. DEVICE 172 EPA EMISSION TEST RESULTS (REFERENCE 97) (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
3.4
3.9
-15
CO
43
43
0
NOx
3.7
2.7
#
27
(1) Results of one test with and without device, using 1972 Federal
Test Procedure (Reference 3).
(2) 1970 Plymouth Duster with a 225-CID 6-cylinder engine and automatic
transmission, and with lean main jets in the carburetor and revised
camshaft, in addition to Device 172. Conical inserts to intake
manifold.
4-82
-------
4.3.L.4 Reliability
This induction modification device contains no moving parts and becomes an integral
part of the fuel inducation system. It is assumed that the reliability of the in-
duction system will be unchanged as a result of the modification, provided the de-
vices are designed and fabricated to preclude structural failures in the use en-
vironment. The, leaner carburetor jets should have no effect on carburetor relia-
bility, but they must be properly selected to avoid engine degradation.
Based on these considerations, Device 172 should have a reliability in excess of
75,000 MMBTF.
4.3.1.5 Maintainability
No maintenance attributable to the device-would be required. The- changed carburetor
jets would require the same maintenance at the same intervals as the original equip-
ment jets.
4.3.1.6 Driveability and Safety
This device was not tested in the retrofit study. The referenced EPA report indi-
cated that the device had a small adverse effect on performance at high loads; how-
ever, this may not be so attributable to the intake manifold modification as to the
other vehicle changes that were tested in combination with the device.
Developer tests indicate that a vehicle equipped with the conical inserts drove as
well as or better than the unmodified vehicle. A 1968 Ford Fairlane was driven
10,000 miles by the developer with no loss of emission reduction effectiveness.
Developer driveability tests have also indicated that some fuel economy may be pro-
vided by the device. With the same 1970 'Plymouth used in emission tests (Table
4-42), fuel consumption test results were obtained as shown in Table 4-44.
Table 4-44. DEVICE 172 INTAKE MANIFOLD MODIFICATION FUEL. CONSUMPTION DATA
REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
AVERAGE MILEAGE PER GALLON
45 MPH
28.3
30.2
7
55 MPH
22.0
28.6
30
65 MPH
20.3
23.1
. 15
AVERAGE
PERCENT
REDUCTION
17
(1) Each test was run over a 75-mile interstate highway route, out and back,
for a total of 150 miles. One test was performed at each mph increment
with and without the conical inserts installed.
(2) Same vehicle as described in Table 4-42, Note (2), with over 36,000 miles
indicated. No tuneup was made before test.
4-83
-------
No safety hazards are indicated by the device. This assumes that:
1. The induction modification inserts maintain structural integrity so as to
preclude their ingestion through the intake valves, with consequent catas-
trophic engine failure,
2. Excessive lean carburetor jets are not used, because they could result in
significant engine performance deterioration or catastrophic failure under
potentially hazardous circumstances.
4.3.1.7 Installation Description
Installation of this device consists in removing the intake manifold and inserting
the intake rams and replacing the primary carburetor jet with one producing a leaner
air-fuel ratio. Adjustment consists in setting the engine idle rpm and the idle
mixture.
Table 4-45 contains a more detailed description of the installation procedure and
identifies tools and special equipment required. Installation can be accomplished
in a normally equipped repair shop with average skills.
Table 4-45. DEVICE 172 INTAKE MANIFOLD MODIFICATION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1. Remove carburetor from intake manifold
2. Remove intake manifold from cylinder heads
3. Install intake rams into intake manifold
4. Reinstall intake manifold on cylinder heads
5. Remove standard primary jets from carburetor
6. Install new primary jets giving a leaner air
fuel ratio
7. Reinstall carburetor on intake manifold
8. Adjust engine to factory specifications for
idle rpm and adjust for best lean mixture
TOOLS, EOUIPMENT
AND FACILITIES
Hand tools
Hand tools
a. Hand tools
b. Intake rams
c. Gasket
Hand tools
Hand tools
a. Hand tools
b. Primary jet
Hand tools
Tachometer
Total Time
TIME
(MIN. )
10
20
5
20
5
5
10
15
1.5 hrs
4-84
-------
4.3.1.8 Initial and Recurring Costs
Table 4-46 summarizes the costs for this device. The developer estimated that the
cost of this device should be $40 to $60, depending on the size and type of engine.
From the information available, it is estimated that the initial cost for this de-
vice, including labor and material, would be $58.74 to $78.74. No recurring cost
would be expected, as the device should not require any maintenance.
Table 4-46. DEVICE 172 INTAKE MANIFOLD MODIFICATION INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Intake rams
b. Primary jet for
carburetor
Gasket
Table 4-45
Table 4-45
LABOR HOURS OR
ITEM QUANTITY
1.25 hrs
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Fuel
17 percent savings
(Table 4-44)
680 gal @ $0.35
per gal over
50,000 mi. (1)
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
6-cyl 8-cyl
$40 - $60
(Included in
above)
$15.62
$3.12
$58.74-$78.74
-$238.00
-$238.00
-$159.26
(1) Based on an assumed national average of 10,000 miles per year and 12.5 mpg.
4.3.1.9 Feasibility Summary
This device, as an intake manifold modification, would appear to be a technically
feasible retrofit device for reduction of CO and HC emissions in the configuration
reported in Table 4-42. Although the initial cost is moderately high, the device
would apparently require virtually no maintenance and could have some fuel economy
benefits. Further testing would be required to verify the emission reduction ef-
fectiveness and fuel economy benefits for a range of used cars, as well as the spe-
cific device configuration for these cars.
4-85
-------
4,3.2 Device 430; Induction Modification
This device consists of a conical nozzle and screen assembly mounted below the car-
buretor throttle plate, between the carburetor base and the intake manifold. The
purpose of the nozzle-screen assembly apparently is to improve vaporization of the
air-fuel mixture. Use of this device is combined with engine adjustments described
later.
The developer has fabricated two units, installed them on two pre-1968 vehicles, and
conducted tests with and without the device in accordance with the 1970 Federal Test
Procedure (Reference 15).
4.3.2.1 Physical Description
As shown in Figure 4-23, the device consists of a conical nozzle insert into which
is fitted a porous conical cup made of three layers of steel screen. The conical
nozzle and porous cup are installed between the carburetor and intake manifold as
shown in Figure 4-24.
Figure 4-23. DEVICE 430 INTAKE MANIFOLD NOZZLE SCREEN CONFIGURATION
4-86
-------
OVERLAP POROUS
MATERIAL
BOHOM OF MANIFOLD
POROUS
MATERIAL
CARBURETOR
GASKET
INTAKE MANIFOLD
Figure 4-24. DEVICE 430 INTAKE MANIFOLD NOZZLE SCREEN INSTALLATION
4.3.2.2 Functional Description
The conical nozzle section of this device has a throat area approximately equal to
that of the carburetor venturi. The wire mesh cup apparently is intended to provide
a high surface area for fuel droplet impingement and subsequent vaporization.
In addition to installation of the vaporizer, the developer also disconnects the
vacuum advance, and adjusts the carburetor automatic choke and idle mixture to maxi-
mum lean settings. Disconnecting the vacuum advance should reduce combustion chamber
temperature, and decrease NOx formation.
4.3.2.3 Performance Characteristics
Performance data provided by the developer are presented in Table 4-47.
4.3.2.4 Reliability
The vaporizer device contains no moving parts and becomes an integral part of the
fuel induction system. It is assumed that the mean-miles-before-total-failure of
the induction system would be unchanged as a result of the modification, provided
the vaporizer is compatible with the specific induction system configuration. The
device reliability should be more than adequate for the 50,000-mile service life
required of a retrofit device. MMBTF should be in excess of 75,000 miles.
4.3.2.5 Maintainability
The device should be inspected and cleaned or replaced whenever the carburetor is
cleaned or overhauled (25,000 MMBM). Maintenance time attributable to the device
itself is estimated to be less than 5 minutes (0.08 hr MTTM). The device is
nonrepairable.
4-87
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Table 4-47. DEVICE 430 INDUCTION MODIFICATION EMISSION TEST RESULTS
PROVIDED BY DEVELOPER (1)
VEHICLE CONFIGURATION
1966 Pontiac (2)
Without Device
With Device
Percent Reduction
1963 Dodge (3)
Without Device
With Device
Percent Reduction
Mean Percent Reduction
POLLUTANT (GM/MI)
HC
8.55
3.83
55.0
3.96
3.46
13.0
34.0
CO
51.7
52.36
-i.o
73.73
58.60
20.0
9.5
NOx
3.38
2.32
31.0
5.06
2.93
42.0
36.5
NUMBER
OF TESTS
1
2
1
1
(1) Tests conducted in accordance with the 1970 Federal Test Procedure
(Reference 15) by Scott Research Laboratories,
(2) 1966 Pontiac GTO with 389-CID engine.
(3) 1963 Dodge Dart with 235^CID engine and automatic transmission.
4.3.2.6 Driveability and Safety
Evaluation of device driveability was not possible, as the developer supplied no
driveability data.
No safety hazards with the device are indicated. In the event of structural failure
of the nozzle screen, it does not appear likely engine failure would be immediately
catastrophic.
4.3.2.7 Installation Description
Table 4-48 itemizes installation requirements for this device. The installation
consists in removing the carubretor, installing the vaporizer screen in the mani-
fold, replacing the carburetor, reducing accelerator pump travel, and sealing off
the distributor vacuum advance. Adjustment consists in regulating idle rpm to new
values, setting idle mixture screws to obtain minimum CO and HC emissions, and set-
ting the automatic choke to the leanest acceptable setting.
It is estimated that installation should take about 0.75 hour. Installation can be
accomplished in a normally equipped repair shop by the average mechanic.
4-88
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Table 4-48. DEVICE 430 INDUCTION MODIFICATION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Remove carburetor and carburetor
mounting gasket.
Clean carburetor mounting and intake
manifold mounting surfaces.
Install vaporizer in manifold making
sure that porous material (screen)
touches bottom of manifold and over-
laps the top edge of the nozzle.
Place carburetor gasket on top of
vaporizer and reinstall carburetor.
Reduce accelerator pump travel 60
percent of its former value.
Remove vacuum advance hose and seal
connections. (Applicable only if
the distributor has both centrifugal
and vacuum advance mechanisms.)
Start engine and check for air leaks.
Set idle speed, with engine at
operating temperatures:
a. At 620 rpm with automatic
transmission in drive.
b. At 700 rpm with manual trans-
mission in neutral.
Set idle mixture screws to leanest
acceptable running or minimum HC
if instrument available.
Recheck idle speed and adjust to.
recommended values as necessary.
Set automatic choke to leanest
acceptable running setting.
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools
Vaporizer device
Hand tools
Hand tools
Hand tools
Tachometer
Tachori ete or engine
analyz >r
Tachometer
Hand tools
Total Time
TIME
(MTN.)
10
2
2
10
2
2
2
8
3
••
2
0.75 hr
4-89
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4.3.2.8 Initial and Recurring Costs
Table 4-49 summarizes the installation costs for this device. From the information
available, it is estimated that the cost for installing this device, including
material, would be $14.37 to $19.37. Recurring costs are not estimated since it is
assumed that any inspection of the device would be required only at the time carbu-
retor maintenance is performed, and the maintenance cost attributable to the device
would be insignificant.
Table 4-49. DEVICE 430 INDUCTION MODIFICATION INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
Labor
1. Installation
2. Test and adjust
DESCRIPTION
Vaporizer device
Table 4-48
Table 4-48
LABOR HOURS OR
ITEM QUANTITY
0.5 hr
0.25 hr
Total Initial Cost
COST
(DOLLARS)
5.00 - 10.00
6.25
3.12
14.37 - 19.37
50,000-Mile Recurring Cost (Refer to paragraph 4,3.2.8)
4.3.2.9 Feasibility Summary
The feasibility of this device for retrofit application is considered to be incon-
clusive until controlled testing is performed to determine the extent to which the
device and the related engine tuneup modifications contribute to the emission re-
duction effectiveness indicated. It is undeterminable from the data provided whether
the reduced emissions indicated by test data were achieved because of adjustments
made at the time of device installation (vacuum advance disconnect, lean idle mix-
ture, high idle speed, etc.), or because of the device.
4-90
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4.3.3 Device 440; Intake Deflection Plate
This device operates on the same air-fuel vaporization principle as Device 430, but
the means of implementing the principle is different.
4.3.3.1 Physical Description
Device 440, shown in Figure 4-25, consists of one component, a plate which fits be-
tween the carburetor and the manifold. The plate has varied shaped deflectors which
extend into the manifold, and the configuration varies for different model-year ve-
hicles. The plate is coated with a nohwettable fluorochemical coating.
4.3.3.2 Functional Description
There are apparently two principles of operation for this device:
1. Deflection of the air-fuel mixture to aid in its vaporization
2. Provision of a nonwettable surface to avoid filming of the mixture on the
deflection prongs.
According to the developer, a nonwettable surface is designed to prevent film
formation on the device plate. Figure 4-26 shows a cross section of a carburetor
with the plate installed and typical configurations of the deflectors that have
been tried by the developer. The shapes of these deflectors are dependent upon
the venturi area and volumetric flow through the particular carburetor.
The following is an extraction from documents supplied by the developer relating *
the theory of operation of the device:
"This invention offers a simple and effective means for improving
engine induction system performance through elimination of wet
film wall flow and by more uniform fuel distribution. This is
accomplished through application of a space age fluorochemical
to a sheet metal plate interposed between carburetor and manifold.
"The operative principles are both simple and familiar. Any
science student who has ever spilled a drop of mercury onto a
surface it does not wet remembers vividly how it shattered into
a myriad of small spheres. It is well understood among combus-
tion engineers that liquid gasoline will not burn and that the
speed of vaporization is proportional to the exposed liquid
surface area. A bit of simple arithmetic confirms that if a
film of liquid is dispersed into spheroids of comparable size
scale by being swept onto a surface it cannot wet, the aggre-
gate exposed area of the spheroids is many times greater than
that of the film."
4-91
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(d) VOLKSWAGEN
Figure 4-25. DEVICE 440 INTAKE DEFLECTION PLATE
VEHICLE MANUFACTURER CONFIGURATIONS
886
Figure 4-26. DEVICE 440 INTAKE DEFLECTION PLATE INSTALLED
AND TYPICAL VARIATIONS (DEVELOPER SKETCH)
4-92
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4.3.3.3 Performance Characteristics
Emission data were not obtainable from the developer of this device. The only test-
ing indicated has been qualitative driveability and fuel consumption runs made on 11
automobiles. A summary of the performance indicated by these trials is shown in
Table 4-50, as provided by the developer.
Table 4-50. DEVICE 440 INTAKE DEFLECTION PLATE TEST EXPERIENCE SUMMARY
PROVIDED BY DEVELOPER
1.
Chevrolet 283
2-Barrel Rochester
Overdrive Transmission
Ford Mustang 289
2-Barrel Automatic
Transmission
Air Conditioned
Ford Mustang 289
4-Barrel, 4-Speed
4.
Oldsmobile F-85
Rochester Ouadrajet
Hydrametic
5. 1965 Chevrolet 6-194
Ragged low speed performance and 14-15 MPG fuel con-
sumption provoked invention. Original carburetor
calibration represented best possible compromise and
changes further degraded performance without improv-
ing economy.
Installation of device cured tendency to stumble
after cornering, made the engine impressively more
responsive and boosted mileage to 19 MPG. With the
device operating to eliminate liquid fuel flow
through engine it became constructive to reduce the
original 0.056 main jets to as small as 0.048 with
21.8 MPG economy at highway speeds. Optimum per-
formance and 20.7 MPG at 65-70 MPH is realized with
0.051 jets. Driveability does not degrade when
vacuum enrichment is disabled.
Distinct improvement in responsiveness. Economy im-
provement from 15.5-16.5 MPG to 20.3 in owners' ser-
vice. Slight further improvement on reducing main
jets from 0.059 to 0.045.
Distinct improvement in responsiveness and in idle
smoothness and adjustment tolerance. Economy im-
proved from 15-17 MPG to 19-20. Further gain of
about 1 MPG accompanied primary jet reduction from
0.048 to 0.045.
Sufficient improvement in responsiveness to be
quickly noticed by owner. Economy improved from 15
to 17 MPG on identical trip. No change attempted in
calibration. '
Noticeable smoother performance and 20-60 MPH accel-
eration time was reduced from 22.2 to 19.6 seconds
on installation of device alone. Retimed at 22.7
seconds when main jet was subsequently reduced from
0.060 to 0.056. Car which is driven mainly in local
service is not in first class condition. Economy is
reported improved from about 16 to 18 MPG.
4-93
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Table 4-50. DEVICE 440 INTAKE DEFLECTION PLATE TEST EXPERIENCE SUMMARY
PROVIDED BY DEVELOPER (CONCL)
8.
9.
10.
11.
1962 Chevrolet 6-235
Rochester 1-Barrel
Powerglide
Transmission
Volkswagen 1300
Solex Carburetor
Ford 1965 LTD - 352
4-Barrel C5AF-1
Automatic Transmission
Dodge Dart 330
2-Barrel Stromberg WW
Code Stamped 3-199
Automatic Transmission
1962 Chrysler
Newport 361 Engine
Stromberg WWC
Carburetor Code 3-201
Manual Transmission
1965 Chevrolet 327
Rochester 4-Barrell
Automatic Transmission
Air Conditioned
Owned and driven in short trip service by secretary
who is enthusiastic about improved performance.
Says it moves out like a big car. (This after jet
was reduced from 0.055 to 0.047). No meaningful
economy data available.
This recent installation yields perhaps the most
convincing performance improvement, in the matter
of improving low speed flexibility to permit smooth
acceleration from less than 10 MPH in third gear.
Idle mixture adjustment which was verified and
marked before installation of device shifted 30°
toward lean afterwards; owner reports economy in his
local use improved from 27 to 30 and 34 MPG on two
checks.
On this installation in which idle mixture settings
were carefully checked before and after device in-
stallation, a change of nearly 90° or 1/4 turn
leaner for speed decline was experienced. Owner re-
ports 15.5 MPG on return trip to Charlotte with air
conditioner running versus 13.8 MPG northbound in
morning chill. Jets have not yet been changed.
Responsiveness definitely improved. Owner reports
quicker starting. No economy data yet available.
Idle adjustment on this installation did not shift.
Noticeable flat spot and stumbling just above idle
definitely cured. Idle adjustment much less tem-
permental. No economy data yet available.
Recent installation on Patent Attorney's car. Idle
smoothness measurably improved and adjustment ren-
dered more definite and less temperamental. No
economy data.
4.3.3.4 Reliability
The device contains no moving parts and becomes an integral part of the fuel induc-
tion system. It is assumed that the mean-miles-before-total-failure of the induction
system would be unchanged as a result of installing the device, provided that the de-
vice is designed and fabricated to preclude structural failures in the use environ-
ment (also refer to paragraph 4.3.3.6). Therefore, the retrofit device standard
reliability requirement of a 50,000 MMBF service life should be equaled or exceeded.
An MMBTF of over 75,000 miles should be achieved.
4-94
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4.3.3.5 Maintainability
The device should be inspected and cleaned or replaced whenever the carburetor is
cleaned or overhauled (25,000 MMBM). Maintenance time attributable to the device is
estimated to be less than 5 minutes (0.08 hr MTTM). The device is nonrepairable.
4.3.3.6 Driveability and Safety
Driveability information provided by the developer (Table 4-50) indicates that the
device may enhance vehicle performance. This information is qualitative, and data
from formal driveability procedures would have to be reviewed to evaluate all drive-
ability characteristics quantitatively.
No safety hazards are indicated. In the event of structural failure of the device,
it is not likely that engine failure would be immediately catastrophic.
4.3.3.7 Installation Description
Installation is accomplished by inserting the device between the carburetor and in-
take manifold. Adjustment consists in setting the engine idle rpm and the idle
mixture.
The developer estimated that installation will take about one-half hour. Table 4-51
itemizes the installation requirements, which indicate an installation time of 0.75
hr. Installation can be accomplished in a normally equipped repair shop by the
average mechanic.
Table 4-51. DEVICE 440 INTAKE DEFLECTION PLATE INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove carburetor from intake
manifold
2. Insert device between carburetor and
intake manifold
3. Install carburetor, reconnect
1 inkage
4. Adjust idle rpm and idle mixture
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Device
Hand tools
Engine analyzer
Total Time
TIME
(MIN. )
10
2
18
15
0.75 hr
4-95
-------
4.3.3.8 Initial and Recurring Costs
The developer estimated the cost of the device to be $3. Table 4-52 summarizes the
installation costs for this device. From the information available, it is estimated
that the cost for installing this device, including material, would be $12.37. There
should be no recurring costs of significance.
Table 4-52. DEVICE 440 INTAKE DEFLECTION PLATE INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
Labor
1. Installation
2. Test and adjust
DESCRIPTION
Deflection Plate
Table 4-51
Table 4-51
LABOR HOURS OR
ITEM QUANTITY
One per carburetor
0.50 hr
0.25 hr
Total Initial Cost
COST
(DOLLARS)
3.00
6.25
3.12
12.37
50^000-Mile Recurring Cost (Refer to paragraph 4.3.3.8)
4.3.3.9 Feasibility Summary
The determination of the feasibility of this device depends on the results of exhaust
emission tests on representative used cars. No exhaust emission data were supplied
for this device. All other characteristics of the device appear to be satisfactory.
4-96
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4.3.4 Device 384: Air-Fuel Mixture Diffuser
This device is similar to Device 430 (paragraph 4.3.2) in providing a screening pro-
cess for the air-fuel mixture as it enters the intake manifold. The screening ap-
proach is different, however, and is claimed by the developer to induce a "catalytic
reaction" in the air-fuel mixture.
4.3.4.1 Physical Description
The developer calls Device 384 a "carburetor catalyst." It consists of a plate fitted
with one or more conical screen cups, each cup made up of two separated wire mesh
screens. The plate contains one conical cup for each carburetor barrel. A two-cup
plate assembly for a two-barrel carburetor is shown in Figure 4-27. The plate assem-
bly is shaped to install as an adapter between the carburetor and the intake manifold.
Figure 4-27.
DEVICE 384 AIR-FUEL MIXTURE DIFFUSER (CONFIGURATION
FOR TWO-BARREL CARBURETOR)
4-97
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4.3.4.2 Functional Description
Figure 4-28 illustrates the installation details of this device. The wire mesh cup
is apparently intended to provide a high surface area for fuel droplet impingement
and subsequent evaporation. The two screen cups are separated from contact with
each other.
The developer states there are many desirable side effects which improve the com-
bustion process itself. According to the developer, the device provides: "A cata-
lytic reaction of the fuel-air mixture prior to entry into the engine to complete
combustion in the combustion chamber." This is claimed by the developer to reduce
"sludge buildup in engine and oil" and to increase mileage and spark plug life. Also,
he claims that: "Use of the carburetor catalyst, as manufactured by the developer,
allows the maintenance of present levels of engine design efficiency using lower
octane, low lead fuels meeting proposed federal fuel standards.
4.3.4.3 Performance Characteristics
Performance data submitted by the developer are presented in Table 4-53. These
data indicate that the developer also uses leaner carburetion and timing retardation
in combination with the device. These engine tuning exhaust modifications would tend
to decrease CO and NOx exhaust emissions, respectively.
4.3.4.4 Reliability
The device contains no moving parts and becomes an integral part of the fuel induc-
tion system. It is assumed that the mean-miles-before-total-failure (MMBTF) of the
induction system will be unchanged as a result of the modification, provided the
device is compatible with the specific induction system configuration. Therefore,
a device reliability requirement of 75,000 MMBTF should be equaled or exceeded.
4.3.4.5 Maintainability
The device should be inspected and cleaned or replaced whenever the carburetor is
cleaned or overhauled (25,000 MMBM). Maintenance time attributable to the device
is estimated to be less than 5 minutes (0.08 hr MTTM).
The device itself appears to be nonrepairable and would be replaced if it fails.
Mean-time-to-repair (MTTR) would thus be the same as the installation time (paragraph
4.3.4.7).
4.3.4.6 Driveability and Safety
The developer did not provide data as to the effect of the device on vehicle
driveability.
No safety hazards are apparent. In the extent of structural failure of the device,
it is not probable that engine failure would be immediately catastrophic. As with
any of the intake manifold screen devices, clogging of the screen could degradate
vehicle performance. This would probably occur gradually and should not therefore
constitute a safety problem.
4-98
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12
I ^•••••••••^^•••^••^d' I
I' viefW 2'lr 2
36
38
Figure 4-28. DEVICE 384 AIR-FUEL MIXTURE DIFFUSER INSTALLATION SKETCH
(FROM DEVELOPER'S PATENT DISCLOSURE)
4-99
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Table 4-53. SUMMARY OF DEVICE 384 AIR-FUEL MIXTURE DIFFUSER
EXHAUST EMISSION DATA PROVIDED BY DEVELOPER (1)
1965 Ford Galaxie
Test
No.
1
2
3
4
1
2
3
4
5
Date (2)
1/19/71
1/19/71
1/19/71
3/01/71
Test
Type
Cold
Hot
Composite
Hot
Hot
Hot
Device
None
None
Carb. Cat.
Carb. Cat.
Timing
(°BTDC)
10
10
9
10
Idle
Mixture (3)
1+11/4
3/4 + 1
7/16 + 3/4
1/4 + 3/8
HC
(ppm-C6)
604
517
547
426
464
310
CO
(%)
3.65
4.92
4.48
4.34
4.88
3.25
NO
(ppm)
1,161
839
951
876
895
1,034
1967 Chrysler 300
1/27/71
1/27/71
1/27/71
3/01/71
3/01/71
Cold
Hot
Composite
Hot
Hot
Hot
Cold
Hot
Composite
None
None
Carb. Cat.
Carb. Cat.
Carb. Cat.
& Modulator
12
12
12
10
9
17/8+2 3/4
15/8+2 1/2
11/3+2
3/4 + 1 3/4
3/4 + 1 3/4
Percent Reduction (4) :
579(4)
416
473
354
368
298
346(4)
168
230
40.2
7.14
5.08
5.80
4.63
3.99
2.23
5.74
2.99
3.95
19.6
415
568
514
640
899
904
293
429
381
29.4
(1) 7-cycle, 7-mode test procedure.
(2) Mileage values = 1/19/71 Ford 48,156
3/01/71 Ford 50,185
1/27/71 Chrysler 40,074
3/01/71 Chrysler 43,793
(3) Number of turns from closed (driver side and passenger side).
(4) Cold start data used as baseline and retrofit values for evaluating Device
384 emission reduction potential in retrofit study program.
4-100
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4.3.4.7 Installation Description
The installation of this device consists in removing the carburetor, installing the
carburetor catalyst on the intake manifold, and replacing the carburetor. The
carburetor catalyst is made so that the carburetor bolts will center the "catalytic
cups" in the manifold bore with at least 0.040 inch clearance. The developer stated
that the "catalyst" will not function if it is installed in contact with other metal-
lic surfaces. Special adapter plate assembly configurations would possibly be re-
quired for different vehicles.
It is estimated that installation would take about one-half hour. Table 4-54 con-
tains a more detailed description of the installation procedure and identifies the
tools and special equipment required. Installation could be accomplished in a
normally equipped repair shop or service station with average skills.
4.3.4.8 Initial and Recurring Costs
The developer did not provide sufficient data on which to base an estimate of initial
and recurring costs. Because of the screen insulation design requirements of the
device, it would appear that the cost of this device might be higher than the other
air-fuel vaporizing devices evaluated. Whether this initial cost would be offset
by recurring savings in fuel economy is not known.
4.3.4.9 Feasibility Summary
Based on the emission data provided by the developer, the specific contribution of
the device to emission control could not be determined in relation to the engine
tuneup adjustments used. Further testing for emission, fuel consumption, and drive-
ability effects would be required on a variety of used cars, to establish the overall
cost effectiveness of the device for retrofit applications.
4-101
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Table 4-54. DEVICE 384 AIR-FUEL MIXTU IE DIFFUSER INSTALLATION PROCEDURES
MINIMUM AVERAGE SKILL LEV:<;;L: AUTOMOTIVE MECHANIC
INSTALLATION & ADJUSTMENT PROCEDURE
I.
2.
3.
4.
5.
6.
7.
8.
Disconnect fuel line, automatic choke,
vacuum line, and throttle linkage to
carburetor.
Replace carburetor to manifold bolts
so carburetor can be lifted at least
3 inches.
Remove old gasket from carburetor/
manifold.
Place carburetor catalyst on mani-
fold with catalyst cups centered
down into the manifold cavity.
Place the carburetor on top of
the gasketed carburetor catalyst
and attach carburetor bolts or
nuts (loosely).
Tighten all carburetor and mani-
fold fasteners to 10 ft-lb with
torque wrench.
Connect fuel line, automatic choke,
vacuum line and throttle linkage to
carburetor. Replace throttle spring.
Electrical check of device for shorts.
Start engine and check for vacuum
leaks.
TOOLS, EQUIPMENT
& FACILITIES
Hand Tools
Hand Tools
Hand Tools
Hand Tools
Torque Wrench
Hand Tools
Volt-ohmmeter
Total Time
TIME
(MINUTES)
5
5
1
1
3
5
8
1
0.5 hr
4-102
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4.4 CARBURETOR MODIFICATION - RETROFIT SUBTYPE 1.2.4
The retrofit study indicated that modification of the carburetor alone is seldom
used as a means of controlling vehicle emissions. More often a change to the
carburetor tuning, such as leaning the air-fuel ratio, is used in combination
with other control methods, such as vacuum advance disconnect, to achieve emis-
sion control. The basic principle that can be used in controlling emissions by
means of the carburetor is that of lean air-fuel mixture (high air-fuel ratio).
This has the effect of not only decreasing the amount of fuel by which pollutants
can be formed during combustion, but of providing the air needed to oxidize CO and
HC,-into carbon dioxide and water. A second principle implementable through the
carburetor is that of providing improved fuel vaporization and homogeneous mixing.
This can extend the mixture lean limit of engine operation (Reference 98).
Possibly the reason carburetors themselves are not often modified by retrofit
developers to operate on the lean air-fuel mixture principle is that an air-bleed
tube to the intake manifold accomplishes the same effect, and it also provides a
marketable product. Similarly, air-fuel vaporization and mixing can be accomplished
more expediently by inserting another device between the carburetor and the intake
manifold, rather than modifying the carburetor - a process that for either lean
mixture or improved mixing would require carburetor teardown. So the approach in
most cases has been to leave the carburetor untouched, except for lean idle adjust-
ment, and to devise add-ons to achieve the desired effects.
Of the 65 devices studied, five were classified as carburetor modifications,
because they directly involve changes to the carburetor components and mode of
operation (see Table 4-1). The emission reduction principles vary. Device 33
appears to produce the same effect as an air bleed device, but accomplishes this
by decreasing the pressure in the fuel bowl, under intake manifold vacuum, thereby
increasing the air-fuel ratio; Device 56, which bleeds heated air and crankcase
blowby through the carburetor throttle plate, also acts as an air bleed. Device
288 provides more thorough air-fuel mixing. Device 317 provides a combination of
air bleed and fuel augmentation to the carburetor base with vacuum advance discon-
nect. Device 295 represents a completely redesigned carburetor that features a
variable venturi to optimize the air-fuel ratio and mixing qualities according to
engine operating requirements.
Thus it would appear that this type of device most frequently incorporates the air-
fuel leaning principle associated with CO exhaust emission control, with some con-
trol of HC through improved airrfuel mixing. Only Device 317 incorporates a
specific combination control for NOx reduction; although as discussed later, Device
295 also indicates some NOx control.
4-103
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4.4.1 Device 33: Carburetor Modification, Main Jet Differential Pressure
This device produces the effect of an air bleed to intake manifold by decreasing
the pressure differential between the carburetor venturi and the fuel bowl during
engine operating modes in which there is high vacuum in the intake manifold. The
device was one of 11 tested during the retrofit study.
4.4.1.1 Physical Description
Figure 4-29 shows Device 33 installed on a standard carburetor. The device con-
sists of an adjustable valve located in a metal tube that attaches between the
carburetor throttle plate and the fuel bowl. The valve is about 1/2-inch in diam-
eter by 1 inch long and is connected by 3/16-inch diameter tubing. The valve adjust-
ment is of the needle-valve type.
STANDARD CARBURETOR
DEVICE 33
DIFFERENTIAL
PRESSURE TUBE
DEVICE 33
ADJUSTMENT
VALVE
BB034
Figure 4-29. DEVICE 33 CARBURETOR MODIFICATION (MAIN JET
DIFFERENTIAL PRESSURE) CONFIGURATION
4-104
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4.4.1.2 Functional Description
One of the controls of the air-fuel ratio in a carburetor is the difference in
pressure across the main fuel jet between the fuel bowl and the venturi. Normally
the fuel bowl is vented to the atmosphere externally and/or to the air cleaner.
The pressure difference between.the carburetor venturi and the fuel bowl depends
on air flow through the carburetor venturi. The air-fuel mixture ratio becomes
higher (leaner) as the difference in pressure is reduced between the bowl and the
venturi.
With Device 33 the fuel bowl vent to the air cleaner or atmosphere is sealed, and
is vented instead to the intake manifold. Under low manifold conditions, such as
acceleration modes, this venting has little effect on the normal air-fuel ratio
of the carburetor; but, under higher manifold vacuum conditions, (such as during
idle or deceleration), the venting lowers the pressure differential and then the
air-fuel mixture is leaner than normal, because less fuel is drawn into the ven-
turi „
In effect, the device constitutes a parallel vacuum circuit to that of the venturi.
This parallel vacuum counterbalances venturi vacuum so as to reduce the amount of
fuel in the air-fuel mixture. On starting there is little or no vacuum, so the
carburetor system functions as .it normally would. Also, in full throttle situa-
tions the manifold vacuum drops and the extra fuel needed for acceleration is
available.
4.4.1.3 Performance Characteristics
A test program was conducted by the developer to determine the air-fuel ratio
characteristics of carburetors with the device installed. Three test cars
were chosen as representative of the various type of older cars on the
highway today:
1. A 1964 Plymouth Valiant with a 170-CID, six-cylinder engine and a
single-barrel carburetor. This car had 65,000 miles without a
major overhaul.
2. A 1965 Rambler with a 232-CID, six-cylinder engine and a two-barrel
carburetor. This car had 105,000 miles without a major overhaul.
3. A 1968 Checker with a standard V-8 engine (a Chevrolet 327-CID) with
a quadrajet carburetor. This car had 41,000 miles without a
major overhaul.
Each car was first tested in the "as-received" condition and then given a minor
tuneup to factory specifications. Each car was then tested on a dynamometer to
determine the air-fuel ratio versus miles per hour. The dynamometer was set up
to require 18 horsepower at 50 mph, and the car was run from 0 to 60 mph in 5-
mph increments. The air-fuel ratio was recorded at each increment. The car
was then stopped and the mixture control was set to produce an air-fuel ratio
of 14:1 at idle.
4-105
-------
With the mixture control operating, the test was repeated. Since the Valiant
would not idle at 14:1 air-fuel ratio, the test was run at 13.8:1 ratio. On
the Rambler, the miles per gallon of fuel were recorded at each 5-mph increment,
The tests were repeated at least three times on each car to check repeatability.
The starting characteristics and the fuel throttle characteristics of each car
were carefully observed.
Figure 4-30 shows the typical values of air-fuel ratio versus miles per hour
for the Valiant, the Rambler and the Checker, respectively. The percentage
increase in the air-fuel ratio was the same for the as-received and the tuned
cases. Along with increased air-fuel ratio, fuel mileage apparently increased
30 percent at 30 mph and 20 percent at 60 mph (Figure 4-30d).
WITH MIXTUHE CONTROL
'WITHOUT MIXTURE CONTROL
MILES PER HOUK
(a) 1964 Valiant
.WITH MIXTURE CONTROL
'ITHOUT MIXTURE CONTIOL
MILES PER HOUR
(b) 1965 Rambler
u
o
i
S 12
'WITH MIXTURE CONTROL
ITHOUT MIXTURE CONTROL
MILES PER HOUR
(c) 1968 Checker
'WITH MIXTURE CONTROL
WITHOUT MIXTURE CONTROL
30 40
MILES PER HOUI
SO W
(d) Rambler Fuel Mileage
Figure 4-30. DEVICE 33 CARBURETOR MODIFICATION (MAIN JET DIFFERENTIAL
PRESSURE) AIR-FUEL RATIO TEST RESULTS (DEVELOPER DATA)
4-106
-------
Table 4-55 summarizes the results of emission tests reported by the developer with
Device 33 installed on these vehicles. Table 4-56 shows the results obtained by
Table 4-55. DEVICE 33 CARBURETOR MODIFICATION (MAIN JET DIFFERENTIAL PRES-
SURE) EMISSION TEST RESULTS REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
9.07
6.27
31
CO
104.86
44.69
57
NOX
2.52
2.68
-6.3
(1) Average of emission results for two 7-cycle, 7-mode
tests with and without device installed.
(2) 1965 Rambler (232-CID) and a 1968 Checker (Chevrolet
327-CID).
Table 4-56. DEVICE 33 CARBURETOR MODIFICATION (MAIN JET DIFFERENTIAL
PRESSURE) EMISSION REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/ CID
1965 Ford 289
Without Device
With Device
Percent Reduction
1965 Chev 327
Without Device
With Device
Percent Reduction
Mean Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS /MILE
HC
10.55
4.99
52.7
7.92
6.89
13.0
32.9
CO
181.80
67.56
62.8
80.01
57.08
28.7
45.8
NOx
1.02
2.26
-121.6
2.32
1.51
34.9
-43.4
FUEL
MILES/
GALLON
11.40
15.43
-35.4
14.24
12.80
10.5
-12.5
(1) Emission results obtained by Olson Laboratories in
tests performed under Contract 68-04-0038 using 1972
Federal Test Procedure (Reference 3). Fuel consump-
tion was measured during these tests.
4-107
-------
Olson Laboratories in tests to the 1972 Federal Test Procedure during the retrofit
study program. The two sets of data shown in these tables indicate the same emis-
sion control characteristics for the device. The results in both cases appear to
be typical of an air bleed device. HC and CO decreased substantially in both test
programs, indicating effective control of those pollutants. NOx increased on the
average of these tests. Additional tests should be conducted to establish the
effect of this device on NOx levels.
4.4.1.4 Reliability
The developer reported that no system failures have occurred in over 90,000 miles of
driving accumulated on test cars during a 15-month period. Considering that the
system consists of only a vacuum line and a fixed orifice (a valve only adjusted
during maintenance), it is estimated that system reliability should exceed 75,000
mean-miles-before-total-failure.
The reliability analysis indicated the possibility of a critical secondary failure
mode (primary failure mode not related to the device) which is discussed under
safety.
4.4.1.5 Maintainability
No routine maintenance would appear to be required, although occasional verifica-
tion of the optimum orifice adjustment might be desirable. Such adjustment would
normally be made during exhaust emissions inspections.
4.4.1.6 Driveability and Safety
This device was tested for driveability on two cars at the Olson Laboratories'
Anaheim facility. Table 4-57 summarizes the results of these tests. The device
indicated driveability characteristics similar to an air bleed device.
A potential safety hazard could occur. In the event the carburetor float bowl
shutoff valve failed in the open position and no fluid check valve were incorporated
in the vacuum line, raw gasoline could be pumped into the intake manifold and con-
stitute a fire hazard.
4.4.1.7 Installation Description
The installation of this device consists in drilling a hole in the top of the car-
buretor fuel bowl and in the intake manifold (or below the carburetor's butterfly
valve), and connecting these two points with the air tube and adjustment valve.
Proper adjustment of the valve after installation can be verified by road test or
by dynamometer test. '
The developer estimated that the cost of the kit and parts would be $8.65 and that
it would take 1 hour of labor for installation. Installation can be accomplished
in the normally equipped garage by the average mechanic, with the exception of the
alternative dynamometer test for adjustment.
Table 4-58 presents the detailed installation procedures and identifies equipment
required for installation, as well as installation time.
4-108
-------
Table 4-57. DEVICE 33 CARBURETOR MODIFICATION (MAIN JET DIFFERENTIAL PRESSURE)
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1
-------
Table 4-58. DEVICE 33 INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
4. Attach vacuum hose to both nipples. This
hose must have adjustment valve to regu-
late vacuum.
5. Adjust the system initially by running the
on a chassis dynamometer. Adjust by open-
ing valve until operation at the desired
fuel-air ratio is achieved.
or
Make adjustment by road test where at a
steady state cruise condition the valve is
opened until a slight drop is noted in rpm
on tachometer. Close valve slightly and
lock in position.
TOOLS, EQUIPMENT
AND FACILITIES
a . Vacuum hose
b. Adjustment valve
c. Hose clamps
Chassis dynamometer
Tachometer
Total Time
TIME
(MIN.)
5
15
15
1 hr
4.4.1.8 Initial and Recurring Cost
Table 4-59 summarizes the costs for this device. From the information available,
it is estimated that the installation cost including material would be about $21.15.
4.4.1.9 Feasibility Summary
The emission test data indicate that Device 33 is capable of lowering HC and CO
emissions effectively. Additional tests should be conducted to establish the ef-
fect of the device on NOx emissions. Although there is a potential safety hazard
with the present design, this problem could be corrected by further design effort.
If this is done, then the combination of the relatively low cost, simplicity, and
emission reduction capability should make the device feasible for retrofit emission
control, particularly on older vehicles.
Because many of the post-1968 cars already are designed and tuned to run on lean
air-fuel mixture, the device may not be as cost effective on those vehicles. Drive-
ability of these cars might be substantially degraded by further air-fuel ratio
increase.
At present, the developer has no plans for marketing the device in the configuration
evaluated, but is developing an improved configuration for retrofit use.
A cost benefit of the device may be its fuel economy. Further testing would be re-
quired to verify this benefit as well as the indicated emission reduction effective-
ness and driveability characteristics over a range of used cars.
4-110
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Table 4-59. DEVICE 33 INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
Adjustment valve
a. Nipples for pipe
connections
b. Vacuum hose
c. Hose clamps
Table 4-58
Table 4-58
LABOR HOURS OR
ITEM QUANTITY
0.5 hr.
0.5 hr.
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Fuel
Average fuel savings
of 12 percent (1)
500-gallon fuel re-
duction x $0.35 per
gallon over 50,000
miles (2)
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
8.65
(Included
above)
6.25
6.25
21.15
-175.00
-175.00
-153.85
(1) Based on only two tests. More tests would be necessary to determine the
statistical significance of the fuel consumption variations due to the
retrofit device.
(2) Based on an assumed national average of 10,000 miles per year at 12.5 mpg.
4-111
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4.4.2 Device 56; Crankcase Blowby and Idle Air Bleed Modification
This device illustrates the use of a heated air bleed to the intake manifold, in
combination with heated recirculation of blowby from the crankcase.
4.4.2.1 Physical Description
As shown in Figure 4-31, Device 56 apparently consists of a specially modified
throttle assembly that fits between the carburetor and the intake manifold. There
are two heating elements, one to heat the crankcase blowby passed through the PCV
valve, and one to heat air which is injected through special air bleed idle jets.
The special idle jets, a spacer to accept the blowby gases, and a vacuum switch to
activate the heaters are part of the system. The only part provided for evaluation
in the form of hardware was an idle jet.
From pictures and a diagram provided by the developer, the spacer appears to be
about 1 inch thick and is shaped to match the carburetor-to-manifold interface.
The heaters are about 3/4-inch in diameter and 3 inches long. The configuration
of the air bleed idle jets is shown in Figure 4-32.
4.4.2.2 Functional Description
The basic principle of operation of this device appears to be to bleed heated air
into the idle jets, thereby leaning the idle air-fuel ratio under medium and high
vacuum conditions and improving the vaporization of the air-fuel mixture, particu-
larly during cold engine operations. The system heats the injected air and also
heats the crankcase blowby passed by the PCV valve into the intake manifold. The
system has a vacuum operated switch to activate the battery-operated heaters in the
two lines. Since the switch would operate off of intake manifold vacuum, the heaters
would apparently be operative during idle and deceleration and other periods of
high intake vacuum.
The effect of heating the air prior to injection is unknown. The concept might be
to enhance vaporization and mixing of the fuel, the blowby, and the air. Since
test results with and without the air heat are not available, no evaluation could
be made of this feature.
4.4.2.3 Performance Characteristics
Emissions data were provided by the developer for three cars tested with the device.
No baseline data were included, so it was not possible to determine if the device
reduced or increased emissions. The developer's data, as summarized in Table 4-60,
indicate that the device may have potential for meeting California emission stand-
ards for retrofit devices of 350 ppm HC and 2 percent CO. The heated air bleed
and crankcase blowby gases appear to have had some controlling effect on the CO
generation during cold start.
The developer supplied information from which these data were obtained indicates
that the device configuration was being modified from test to test. The details
of these modifications were not reported by the developer. The test report for the
6-5-70 test indicated that the carburetor modification resulted in slightly richer
mixture and higher emissions.
4-112
-------
VACUUM
SWITCH.
EXHAUST GAS
RECIRCULATION
AIR BLEED LINES
CARBURETOR
THROTTLE ASSEMBLY
Figure 4-31. DEVICE 56 CRANKCASE BLOWBY AND IDLE AIR BLEED MODIFICATION
(DEVELOPER PHOTO)
Figure 4-32. DEVICE 56 SPECIAL AIR BLEED IDLE JET
4-113
-------
Table 4-60. DEVICE 56 CRANKCASE BLOWBY AND IDLE AIR BLEED MODIFICATION:
SUMMARY OF EXHAUST EMISSION DATA REPORTED BY DEVELOPER
TEST
DATE
3-27-67
3-28-67
3-30-67
6-3-70
6-5-70
9-22-71
VEHICLE CONFIGURATION
1965 Ford Fairlane
289-CID engine and
device
Same
Same
Same (with unspeci-
fied engine
modifications)
Same (with unspeci-
fied carburetor
modification)
1967 Ford with 289-
CID engine and device
POLLUTANT
HC (PPM)
274
330
348
420
437
5.20 gin/mi
CO (%)
0.9
1.9
0.4
0.53
0.84
45.72 gm/mi
NOx (PPM)
(Not measured)
*
(Not measured)
(Not measured)
1,378
1,814
3.23 gm/mi
TEST
TYPE
(1)
(2)
(1)
(2)
(2)
(3)
(1) Two 7-mode hot cycles.
(2) One 7-cycle, 7-mode test.
(3) 1972 Federal Test Procedure (Reference 3). ,
4.4.2.4 Reliability
Functionally, the device consists of two heating elements and a vacuum switch.
Proper design of the heating elements, and selection of the switch for adequate
load rating should result in a potential device reliability of over 75,000 MMBTF.
4.4.2.5 Maintainability
Maintenance requirements would be anticipated during the 12,000-MMBM routine vehicle
maintenance period. These requirements would include:
1. Inspection of hoses for deterioration
2. Inspection of heating elements for thermal output
3. Inspection of vacuum switch for function
4. Cleaning/replacement of air bleed line filter
5. Cleaning of idle jet air bleed holes.
4-114
-------
It is estimated that the indicated maintenance could be performed in less than 20
minutes (0.3 hr MTTM).
Repair times would be dependent upon the specific vehicle installation configura-
tion. However, mean-time-to^repair (MTTR) of the above items should not exceed
0.75 hr.
4.4.2.6 Driveability and Safety
Since this device was not tested in the retrofit study and the developer provided
no driveability data, the effects of this device on driveability could not be
determined.
The heating elements must be designed to fail in the open circuit mode as opposed
to shorted turns (if wire-wound), to preclude excessive temperatures which could
cause a fire hazard. Thermal cut-outs could be provided to eliminate the potential
overtemperature hazard.
4.4.2.7 Installation Description
The installation of this device appears to consist in replacing the idle mixture
screws in the carburetor throttle assembly with special air bleed screws, mounting
a vacuum switch and heater assemblies for the air bleed and the blowby lines, con-
necting the heater electrical leads, installing the assembly between the carburetor
and intake manifold, and connecting the air and PCV hoses. Table 4-61 summarizes
the installation requirements.
Table 4-61. DEVICE 56 INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1. Replace idle mixture screws with air
bleed screws
2. Mount vacuum switch/heater assemblies
on convenient location on carburetor
along with air bleed and EGR hoses
3. Attach heater electrical connection
to engine-run side of ignition switch
4. Install adapter plate between carbu-
retor and intake manifold and connect
air bleed and blowby hoses
5. Adjust idle rpm and idle mixture
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Idle mixture screws
a. Hand tools (may re-
quire drill and tap)
b. Vacuum switch
Hand tools
a. Hand tools
b. Adapter plate
Tachometer
Total Time
TIME
(MIN. )
10
20
15'
30
15
1.5 hr
4-115
-------
4.4.2.8 Initial and Recurring Costs
Table 4-62 summarizes the installation costs for this device. From the information
available, it is estimated that the initial cost of installing this device, includ-
ing material, would be about $53.74. Recurring maintenance cost would be about
$3.75 every 12,000 miles (MMBM), based on 0.3-hr MTTM and $12.50 per hour labor rate.
4.4.2.9 Feasibility Summary
The feasibility of this device could not be determined, because of the lack of emis-
sion data comparing device performance to the same test vehicle without the device
installed.
Table 4-62. DEVICE 56 INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Adapter plate
b. Vacuum switch
c. Idle mixture screws
Hose
Table 4-61
Table 4-61
LABOR HOURS OR
ITEM QUANTITY
1.25 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost;
Labor
1. Periodic
maintenance
Refer to paragraph
4.4.2.5
0.3 hr every 12,000
miles @ $12.50/hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
35.00
(Included
in above)
15.62
3.12
53.74
15.00
/
15.00
68.74
4-116
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4.4.3 Device 288; Carburetor Main Discharge Nozzle Modification
This device provides a modification to the carburetor main discharge nozzle to im-
prove air-fuel mixing. It was tested for emission reduction effectiveness, fuel
consumption, and driveability in the retrofit test program.
4.4.3.1 Physical Description
Figure 4-33 shows the components that comprise Device 288. The basic device is
known as a vortex generator. It mounts inside the carburetor above the main jet
outlet to the venturi. One vortex generator is required for each carburetor ven-
turi. Each is about 1/2-inch in diameter and 1/2-inch long.
4.4.3.2 Functional Characteristics
The Device 288 vortex generator operates on the principle of improving the air-fuel
vaporization by initiating the air-fuel mixing within the main fuel nozzle, rather
than in the venturi itself. The vortex generator also is intended to promote
turbulence within the venturi, further diffusing the air and fuel mixture when it
is discharged into the venturi. According to the developer, this should prevent
laminar flow in the venturi, provide more complete vaporization of the mixture, and
reduce fuel filming and depositing on the walls of the carburetor and manifold.
CARBURETOR
MAIN DISCHARGE
NOZZLES
VORTEX GENERATORS
INSTALLED
VORTEX GENERATORS
REMOVED
BB032
Device 288 Vortex Generators Installed on 2-Barrel Carburetor Main Discharge Nozzle
Figure 4-33. DEVICE 288 CARBURETOR MAIN DISCHARGE NOZZLE MODIFICATION
4-117
-------
4.4.3.3 Performance Characteristics
During the retrofit test program, two cars were tested by the 1972 Federal Test
Procedure with Device 288 installed. The results of these tests show a substantial
CO reduction and some NOx increase.
Table 4-63. DEVICE 288 CARBURETOR MAIN DISCHARGE NOZZLE MODIFICATION
EMISSION REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Ford 289
Without Device
With Device
Percent Reduction
1961 Chevrolet 283
Without Device
With Device
Percent Reduction
Mean Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS /MILE
HC
6.59
6.18
6.2
4.54
4.45
2.0
4.1
CO
117.45
71.78
38.9
70.78
46.13
34.8
36.9
NOx
3.28
3.34
-1.8
2.39
3.24
-35.6
-18.7
FUEL
MILES/
GALLON
14.5
14.5
0
16.8
14.8
11.9
5.95
(1) Emission results obtained by Olson Laboratories in tests performed under
Contract 68-04-0038 using 1972 Federal Test Procedure (Reference 3).
Fuel consumption was measured during these tests.
Table 4-64 presents a summary of emission reduction data provided by the developer.
The emission control configuration of the vehicles used in the Table 4-64 tests is
not known.
4.4.3.4 Reliability
The vortex device contains no moving parts and becomes an integral internal part in
the carburetor. It is assumed that the mean-miles-before-total-failure of the car-
buretor would be unchanged as a result of this modification. Reliability of the
device should be more than adequate for a 75,000-mile (MMTBF) service life.
4.4.3.5 Maintainability ' , •
No additional routine maintenance is apparently required with the device installed.
4-118
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Table 4-64. DEVICE 288 SUMMARY OF DEVELOPER-REPORTED MEASUREMENTS
BY INDEPENDENT LABORATORIES
CABS MANUFACTURED PRIOR TO
FACTORY INSTALLED EMISSION
CONTROL SYSTEMS
1962 FORD GALAXU 332 cu.ln.
Hot Tent : Bate
Partially Equipped
Reduced by:
Reduced by:
1962 CHF.VROLET (Pick-up Truck)
Miles over 196,000
Hot Teat: Base
Totally Equipped
Reduced by:
1963 CHEVROLET (6 Cylinder)
Hot Test: Base
Equipped
Reduced by:
1964 VOLKSWAGEN
Hot Tesci Base
Equipped
Reduced by:
1965 CHF.VROLET (Inpala)
Hot Test: Base
Equipped
Reduced by:
CARS MANUFACTURED AFTER 1965
1968 FOLD CALAXIE 302 cu.ln.
Hot Test: Base
Partially Equipped
Reduced by:
Totally Equipped
Reduced by:
Average of 1968 FORD 302 cu.ln.
1969 PLYMOUTH FURY
Hoc Teat: Base
Equipped
Reduced by:
1971 FORD MAVERICK 230 cu.ln.
Hot Test: Base
Equipped
Reduced by:
1971 CHRYSLER NEWPORT 383 cu.lo.
Hot Teat: Bate
Equipped
Reduced by:
CARS HANITACTURED AFTER 1965
1971 CHRYSLER NEVPORT 383 cu.ln.
Hot Test: B«BB (Repeat)
Specifically Set for NO Control
Reduced by:
Son Pb (Non-Leaded)
Reduced by:
1972 California Standard
1975 Proposed Standard
Present UseJ Car California Standard
^U
70 gm/mi
I. to- J9
.90
44 10 5
731
.21 5. 01
871
2.19
0.79
64!
4.77
2.07
561
6.47 78.29
2.09 25.32
671
CO
I gr/«
1.39 31.44
0.60 14.28
55Z
.95 22.6
.27
71.51
.11 4.29
.17 4.05
821
1.49 •
0.48 11.43
.29 6.90
401
.85 14.41
.43 8.29
501
.96 /5.91
.18 4.85
811
CO
I gr/a
.96 29,91
.22 5.99
771
.19 5.13
SOX
4 j
23
11
2.0 50
nij
ppm gm/mi
2271 28.9
2048
326 4 30
851
311 3. 95
861
543
215
61Z
398
255
361
3060 19.73
645 4.16
781
UC
ppn gr/n
470 5.96
229 2.90
511
192 2.44
59 .74
69!
25} 3.40
355 4.51
401*
338
203 2.57
156 1.97
24Z
98 1
92 .94
61
80 1.14
40 .57
sot '
HC
pp« gr/n
80 1.14
34 ..48
57. SZ
26 .37
67Z
2. 5
1.5
.5
350 5.0
INUX
ppm gm/mi
1476 5.8
1804
1288 4 922**
14Z
1351 5.27
10Z
1573
1171
26Z
415
466
11Z*
969 1.82
696 1.28
291
NO
X
tjm gr/«
1227 4.49
818 2.90
35Z
947 3.69
854
9Z
906 3.41
542 2.11
431
1389
2428 8.68
2146 7.71
az
1277 4.00
1148 3.36
17Z
864 3.62
940 3.89
81*
NO
ppo gr/n
864 3.62
684 2.70
25Z
767 3.23 «•••
HZ
8.0
3.0
.9
800 3.0
Meaurements
Taken By:
Air Resource*
Air Resources
Olson Laboratories
Sorrls
Korrla
Olson Laboratories
Olaon Laboratories
MEASUREMENTS
TAXES 8T:
Olson Laboratories
Air Reaourcea ***
Air Resources
Olson Laboratories
ARfl Publication
Olson Laboratories
Olson Laboratories
Olson Laboratories
Olson Laboratories
Olson Laboratories
MEASUREMENTS
TAKEN BY:
Olson Laboratories
Olson Laboratories
'Deterioration
••During the test, fuel co
••*Low Octane
as neasured and according to Scott report 161 to 21* less consumption was registered.
Average reduction;
Note: One 7-cycle, 7-mode test was performed for each test condition.
4-119
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4.4.3.6 Driveability and Safety
Table 4-65 summarizes the driveability results of retrofit program tests. Baseline
driveability data on Car 2 were obtained but the driveability test with the device
installed was aborted. The car stalled during this test and would not restart. The
exact cause for the failure to start could not be determined at that time.
During the installation of the device by the developer on Car 6, the vacuum advance
was plugged and the choke plate was partially cut away to provide clearance for the
installed device. This procedure was not carried out on the installation on Car 2
and may have been the reason for different results.
The retrofit study driveability tests indicate that some increase in fuel consump-
tion may be attributable to the device. No safety hazards were indicated.
Table 4-65. DEVICE 288 CARBURETOR MAIN DISCHARGE NOZZLE MODIFICATION
DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL.
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1 ,
(1)
CAR NO. 2
This test was
aborted. The
car stalled
during the test
with the device
installed and
would not re-
CAR NO. 3
(1)
CAR NO. 4
(1)
CAR NO. 5
(1)
CAR NO. 6
Decreased stall
during start
deceleration
Decreased start
time during
cold start; de-
creased stumble
during cold
start accelera-
tion
Decreased from
18.0 to 14.9
Increased from
26.0 to 30.0
Average decrease of 5.95 percent (reference Table 4-63)
(1) Device No. 288 was not tested on these vehicles.
4-120
-------
4.4.3.7 Installation Description
The installation of this device consists in removing and disassembling the carbure-
tor, replacing the main nozzle assembly with a modified nozzle with vortex generator
installed, reassembling the carburetor, and replacing it on the engine. Tuneup con-
sists in adjusting the carburetor idle to provide smooth operation. The developer
estimated one-half hour labor for installation, and estimated cost of the device at
$18 to $25. From the actual installation of this device, it appears that 1.25 hours
for installation is a more realistic figure.
Table 4-66 describes the installation requirements. Installation can be accomplished
in a normally equipped repair shop with average mechanic skills.
Table 4-66. DEVICE 288 CARBURETOR MAIN DISCHARGE NOZZLE MODIFICATION
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1. Remove and disassembly carburetor
2. Remove main jet nozzle assembly; drill and
tap threads
3. Insert device into main nozzle assembly
4. Reinstall nozzle assembly into Carburetor
5. Reinstall carburetor onto intake manifold
6. Adjust carburetor idle
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools
Hand tools, device
Hand tools
Hand tools
Exhaust analyzer
Total Time
TIME
(MIN. )
10
30
5
10
5
15
1.25 hr
4.4.3.8 Initial and Recurring Costs
Table 4-67 summarizes the costs for installation and operation of this device.
From the information available, it is estimated that the total cost of this instal-
lation, including material, would be from $33.62 to $40.62. As noted, no recurring
maintenance costs are indicated.
4.4.3.9 Feasibility Summary
Tests conducted by Olson Laboratories during the performance of this contract showed
that the device reduced CO emissions by 30 to 40 percent, but had no desirable effect
on HC and NOx emissions. Considerable modification was required to the carburetor
to install the device, and if the device was to be removed, new parts for the car-
buretor would be required. Because of the cost and labor involved in modifying the
carburetor, and the relatively small changes in emission results, this device does
not appear practical as a retrofit device for older cars.
4-121
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Table 4-67. DEVICE 288 CARBURETOR MAIN DISCHARGE NOZZLE MODIFICATION
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
Labor
1. Installation
2. Test and Adjust
DESCRIPTION
Venturi assembly
Table 4-64
Table 4-64
LABOR HOURS OR
ITEM QUANTITY
1.00 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Fuel
2. Labor
Average increase in
fuel consumption of
5.95 percent (refer
to Table 4-66) (1)
None (no maintenance
assumed - refer to
paragraph 4.4.3.5)
238-gallon fuel increase
x $0.35 per gallon over
50,000 miles (2) :
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
18.00-25.00
12.50
3.12
33.62-40.62
83.30
83.30
123.92
(1) Based on only two tests. More tests would be necessary to determine the
statistical significance of the fuel consumption variations due to the
retrofit device.
(2) Based on an assumed national average of 10,000 miles per year at 12.5 mpg.
4-122
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4.4.4 Device 295: Variable Venturi Carburetor
This device was the single retrofit device incorporating a completely redesigned
carburetor. Device 295 has been tested by the developer with and without exhaust
gas recirculation. During the retrofit study, the device was tested using the
carburetor alone as the control method.
4.4.4.1 Physical Description
Device 295 is called a variable venturi carburetor. As shown in Figure 4-34, this
device is intended to replace the conventional carburetor in its entirety. The unit
provided by the developer for evaluation in the retrofit study program replaces the
standard four-barrel carburetor and is similar in size and weight to that carburetor.
4.4.4.2 Functional Description
The following design and functional description of the variable venturi carburetor
has been extracted from information supplied by the developer:
"Design Description - When compared to contemporary carburetors,
tne variable venturi carburetor appears to be very simple, because
it contains relatively few parts (approximately 65 for the WC
and about 255 for a competitive four-barrel model). This low-
parts count is due, for the most part, to the method by which
fuel is metered. Metering is directly governed by the magnitude
of air mass flow at the moment and the associated calibration
of the variable orifice mechanism. The orifice size is de-
termined mechanically by the relative deflection of spring
loaded venturi plates, which are immersed in the carburetor
inlet air flow.
"The angular deflection of these plates is proportional
to the aerodynamic force acting upon them and, since the
force is directly related to properties of the flowing air
mass, the force will change in proportion to changes in
ambient air density. It may be shown that, with proper
geometric design of the carburetor intake and venturi
plates, the carburetor performance will remain relatively
unaffected by normally experienced extremes in driving
altitude (or by humidity and temperature).
"Very good vaporization of the fuel and mixing with the air
is achieved by the use of a fuel distributing nozzle bar
which extends across the throat of the carburetor. Appro-
priate aerodynamic shaping and the proper location of fuel
orifices ensure a good dispersion of fuel into the airstream.
This arrangement of fuel introduction and the geometry of the
throat cross-section and throttle valves ensure a favorable
distribution'of the air-fuel mixture at the entry to the in-
take manifold.
"Carburetor Functional Description - Figure (4-35) presents a
coded schematic drawing of the variable venturi carburetor.
In operation, fuel is supplied under pump pressure through
4-123
-------
(a) Top View
(b) Bottom View
Figure 4-34. DEVICE 295 VARIABLE VENTURI CARBURETOR
4-124
-------
ED INTAKE AIR
, . UNMETERED
L-J FUEL
METERED
FUEL
MIXED AIR
E2D AND FUEL
Figure 4-35.
DEVICE 295 VARIABLE VENTURI CARBURETOR FUNCTIONAL DIAGRAM
(DEVELOPER SKETCH)
a fuel line (1) into the float chamber (4). The fuel level
is maintained by the now quite standard float actuated needle
valve mechanism. The spring loaded venturi plates (7) take a
position from closed, at engine off, to an open position pro-
portional to the unbalanced pressures between aerodynamic force
produced by the incoming air (6) and the engine manifold pres-
sure in the nozzle bar chamber. The amount of air induced into
the venturi is determined by the manually controlled position
of the throttle plates (9). Fuel, in correct proportion to the
air flow mass, is metered through the variable orifice existing
between the end of the fuel pickup arm (5) and the calibrated
fuel ramp (11). The position of the fuel pickup arm, relative
to the ramp, is determined by mechanical connection through
gearing to the positioning of the variable venturi plates.
Fuel is induced into the fuel pickup arm (5) and into the fuel
distributor nozzle bar (8) by the differential in pressure be-
tween air in the float chamber and that at the fuel orifices in
the nozzle bar. The air-fuel mixture (10) then passes by the
throttle plates and into the intake manifold.
"For acceleration, rapid opening of the throttle plates, in the
presence of a lag in opening of the venturi plates, produces a
pressure in the nozzle bar chamber which is lower than that which
will be reached in the steady-state condition. This tends to
accelerate fuel flow to compensate for the normal liquid
inertia under such conditions. In addition, the inertia
4-125
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of the venturi plates carry them (upon opening) somewhat
further open than that required by the steady-state con-
dition, thereby allowing a larger fuel metering orifice.
Together, these mechanisms, accommodated by design for
proper spring constants and damping, eliminate the heed
for an acceleration pump. During deceleration, the char-
acteristic of this carburetor is somewhat better than that
of conventional equipment because the fuel flow can come
from only one orifice which is in its minimum size (idle)
configuration.
"A choking action for cold starts is inherent in the design,
but can be adjusted for special cases by inclusion of one
over-ride bimetallic spring at the venturi plates."
4.4.4.3 Performance Characteristics
Testing performed on the variable venturi carburetor by the developer with and with-
out exhaust gas recirculation, is described in the following excerpts from informa-
tion supplied by the developer, followed by retrofit program test results with the
carburetor alone:
"Early Prototype Carburetor Test Results - Development testing
has been accomplished on various engine and chassis dynamometers
and on private as well as competitive automobiles. In large
part, the detail elements of the carburetor were proven and/or
improved by this process. In the performance category of testing,
both horsepower results and economy have been shown to be at least
as good as those from late model vehicles. In every case, where
comparisons were made, it was ascertained that the complete engine
and components package were well maintained and adjusted to manu-
facturers' specifications. Examples in the performance category
are as follows:
"Results of Preliminary Exhaust Emission Tests - In January 1971
and later in March, preliminary testing was conducted at the Scott
Research Laboratories facilities in Wilmington, California. The
early tests were run to evaluate the variable venturi carburetor
relative to the new motor vehicle emission standards. The criterion
was established that the carburetor would be adjusted for satisfactory
driveability on a lean fuel-air mixture setting. A second set of tests
were conducted in March to evaluate the WC for application to modify
used cars of model years 1955-1965. In these tests, the carburetors
were set to richer mixtures, and an exhaust recycle was introduced
(but not in optimum configuration) for some of the runs.
"The test vehicle was a 1966 Ford Mustang, specially equipped with
the Atlantic Richfield Corporation (ARCO) exhaust gas recycle
system. The system was "locked out" for the January test and
for one of the tests run in March. When it was connected for
March testing, no attempt was made to properly synchronize the
recycle valve and the throttle. Therefore, the results, although
quite satisfactory, are not as good as they can be.
4-126
-------
"The standard federal seven-mode driving cycle was followed
(from hot start because these were development tests) ; approxi-
mate corrections have been made to the data to convert to the
expected values for "cold" start. A Scott Auto Exhaust Analysis
System (Model 103-11) was used in conjunction with a Scott driver
aid (Model 201-A). Bag samples were also taken for all runs to
provide average full-cycle data for HC, CO and NOx.
"The vehicle was operated on a Clayton chassis dynamometer. The
January tests, showing the "Standard" vehicle data and the data
for the vehicle with the WC and no exhaust recycle, are presented
below:
CO NOx
GM/MI GM/MI
Vehicle in Standard
Condition (with Exhaust 1.84 9.3 0.87*
Recycle) Approximately
Vehicle with WC Carburetor
(no Exhaust Recycle) 1.28 8.5 2.07
* This value would be about 8 times higher without exhaust
recycle.
"Because these results on the WC were achieved with an
air-fuel ratio of 15:1 or more experience indicates that
a richer mixture, while increasing HC and CO, will be
accompanied by a good reduction of NOx. The emission
values are then expected to be close to the required
values of the standards for 1974 new vehicles. If ex-
haust recycle is incorporated, the value may be close to
the 1975 required standards.
"The March test data, as previously stated, reflects an
attempt to measure the performance of the WC relative to
the requirements for modification to the used car popula-
tion of model years 1955-1965. These data in preliminary
form are presented below.
HC
GM/MI
Used Car Standard 3.6
WC (No Recycle) Rich 1.8 42 2.47
WC (Recycle) Lean 2.86 32 1.22
"With optimized exhaust recycle, both the rich and the
lean condition carburetors would show some improvement."
During the retrofit study, Device 295 was tested on a 1965 Ford using the 1972
Federal Test Procedure. Table 4-68 summarizes the results of this test. These
results indicate that the device, when used alone may provide a relatively small
reduction of CO and NOx, but not a substantial amount. The device indicates a
10 percent loss in fuel economy over the vehicle with a standard carburetor.
4-127
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Table 4-68. DEVICE 295 VARIABLE VENTURI CARBURETOR EMISSION REDUCTION
AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Ford 390
Without Device
With Device
Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS/MILE
HC
8.35
11.43
-36.9
CO
109 .8 6
87.94
20.0
NOx
2.32
1.73
25.4
FUEL
MILES/
GALLON
11.0
9.9
10.0
(1) Emission results obtained by Olson Laboratories in one
set of tests performed under Contract 68-04-0038 using
1972 Federal Test Procedure (Reference 3). Fuel con-
summation was measured during these tests.
4.4.4.4 Reliability
The developer stated that engineering judgment indicates that the variable venturi
carburetor (WC) should have much higher reliability than other existing carburetors,
Because the WC contains only about 25 percent of the parts of a conventional four-
barreled carburetor, the developer's statement is reasonable for a fully production
engineered WC. The WC reliability is estimated to be in excess of 75,000 mean-
miles-before-total-failure.
4.4.4.5 Maintainability
The developer stated that no maintenance is required except for a simple spring ad-
justment done twice during lifetime of a vehicle. It is assumed that this spring
is the one that controls the intake venturi plates.
Examination of the prototype WC indicates that it would require cleaning similar
to a conventional carburetor. No detail part maintenance would be anticipated
prior to 50,000 miles: however, carburetor cleaning should be performed every
12,000 miles. Therefore, this device is estimated to have an overall MMBM of
12,000 miles. MTTM is estimated to be approximately 0.5 hour. These estimates
would require review of the production WC for verification.
4.4.4.6 Driveability and Safety
Table 4-69 summarizes the driveability results of tests performed during the retro-
fit study. The device was tested on one car at the Olson Anaheim facility, both
with and without the device installed. It appeared that the starting difficulty
could be attributed to the manual choke and the fact that there is no starting
fuel groove cut in the acceleration ramp. During the performance of this test, the
4-128
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Table 4-69. DEVICE 295 VARIABLE VENTURI CARBURETOR DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS (i)
CAR NO. 1
(1)
CAR NO. 2
0)
CAR NO. 3
(1)
CAR NO. 4
(1)
CAR NO. 5
Increased stall
during cold
start decelera-
tion
Increased start!
number of attemp
during cold star
stall during col
increased stretc
stumble during c
acceleration; de
time during hot
hesitation dlirin
nppeJ.*.r»T.Tn|i ^
Increased from
9.2 to 10.3
Increased from
23 to 27
CAR NO. 6
(1)
ig time and
:s to start
;; increased
I start idle;
liness and
>ld start
:reased cranking
(tart t increased
E hot start
Average decrease of 10.0 percent (reforence Table 4-68)
(1) Device No. 295 was not tested on these vehicles.
ignition timing was inadvertently set wrong. Ignition timing should have been set
at factory specifications and it was believed that this was the case before the test.
It was discovered later that, in fact, the timing was retarded from what factory
specifications called for. A retest was offered at a later date, but the developer
did not bring all components of the device. No more test time was available for a
second rescheduling.
No inherent safety hazard was identified. However, a critical review should be per-
formed on each specific Device 295 installation and interface configuration to assure
that the device cannot jam at full throttle.
A.A.4.7 Installation Description
Table 4-70 itemizes installation requirements for this device. The installation
consists in removing the presently installed carburetor and replacing it with the
variable venturi carburetor. Adjustment of the device is performed by adjusting
the throttle linkage as required for it to operate properly. Adjustment of the
engine consists in setting the idle mixture and idle rpm. The developer estimated
one-half hour labor for installation and a retail cost of $65 to $70 for the device.
4-129
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Table 4-70. DEVICE 295 VARIABLE VENTURI CARBURETOR INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: Automotive Mechanic
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove carburetor.
2. Install adapter plate for specific
engine .
3. Install new variable venturi
carburetor.
4. Install throttle linkage adapters
as required.
5. Adjust throttle linkage and
automatic transmission dashpot
as required .
6. Adjust idle rpm and mixture.
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
a. Hand tools
b. Adapter plate
a. Hand tools
b. Variable venturi
c. Carburetor
Hand tools
Hand tools
Engine analyzer
Total Time
TIME
(MEN.)
6
2
6
3
13
15
0.75 hr.
Table 4-70 defines the installation requirements. Installation can be accomplished
in a normally equipped repair shop with average mechanic skills.
4.4.4.8 Initial and Recurring Costs
Table 4-71 itemizes the overall costs required to purchase, install, and operate
the device. It is estimated that the total cost of the installation, including
material, would be from $74.37 to $79.37. Recurring cost might be incurred because
of the indicated increase in fuel consumption (Table 4-68).
4.4.4.9 Feasibility Summary
In the single test conducted during the retrofit study program, Device
295 reduced CO by 19 percent and NOx by 25 percent, but increased HC by 36.9 per-
cent. Driveability of the car with the device installed was poor, and gasoline
mileage decreased significantly. Because of the resulting low cost effectiveness of
the device, it appears that it would not be a reasonable retrofit device to control
exhaust emissions on used cars. Additional testing would be required on a variety
of used cars to verify these results conclusively.
4-130
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Table 4-71. DEVICE 295 VARIABLE VENTURI CARBURETOR INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and
adjust
DESCRIPTION
a. Adapter plate
b. Variable venturi
c. Carburetor
Gaskets
Table 4-70
LABOR HOURS OR
ITEM QUANTITY
0.5 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Fuel
Labor
1. Cleaning
Average fuel increase
of 10 percent (refer
to Table 4-68) (1)
Paragraph 4.4.4.5
400-gallon fuel increase
x $0.35 per gallon over
50,000 miles (2)
0.25 hr every 12,000
miles @ $12.50 per hr
Total Recurring Cost
Total Costs
COST
(DOLLARS)
65.00-70.00
(Included in
above)
6.25
3.12
74.37-79.37
140.00
12.50
152.50
231.87
(1) Based on one test only. More tests would be necessary to determine the
statistical significance of the fuel consumption variations due to the
retrofit device.
(2) Based on an assumed national average of 10,000 miles per year at 12.5 mpg.
4-131
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4.4.5 Device 317: Carburetor Modification with Vacuum Advance Disconnect
This device apparently is based on the concept of augmenting the carburetor with a
parallel air-fuel mixture circuit between the carburetor bowl and the intake mani-
fold. The device appears to be basically an air bleed to the intake manifold that,
under high vacuum, also draws fuel into the air bleed. At engine rpm above idle,
the vacuum advance is also disconnected.
4.4.5.1 Physical Description
As shown in Figure 4-36, Device 317 consists of two basic components. One is a unit
containing an expansion chamber, air bleed jet, and a gulp valve. It is about 1
inch in diameter and 3 inches long, and mounts on the carburetor. It is connected
to the carburetor fuel bowl and to the intake manifold or carburetor base through a
tube or hose.
The second component is a distributor vacuum advance disconnect valve about 3/4 inch
in diameter and 3 inches long that connects to the throttle operating mechanism of
the carburetor.
4.4.5.2 Functional Description
Device 317 operates on the principle of bleeding air and gasoline into the intake
manifold according to manifold vacuum. Figure 4-37 shows a breakdown of parts in
the device. The line to the fuel bowl is mounted in the carburetor with the end
below the level of the fuel in the bowl. The other end of this line goes to the
intake manifold or carburetor base to sense engine vacuum.
When vacuum is present, a small amount of gasoline flows from the fuel bowl through
the line and mixes in the expansion chamber with air entering through the gulp valve.
The flow is limited by the size of the jet and gasoline orifice. More air will be
inducted through the gulp valve depending on increases in intake manifold vacuum.
To make the engine run properly with the device installed, the idle air-fuel ratio
of the carburetor must be reset to 15:1.
The distributor vacuum advance disconnect valve attaches to the throttle opening
mechanism. No discussion of it was provided by the developer as to its theory of
operation or installation instructions; however, it apparently disconnects the vac-
uum advance whenever the accelerator is actuated.
4.4.5.3 Performance Characteristics
Test data on exhaust emission submitted by the developer are summarized in Table
4-72. The data shows that the device has some capability to reduce NOx emission.
HC and CO are reduced to a lesser extent.
4-132
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TUBE TO
CARBURETOR
BASE
CARBURETOR FUEL
BOWL CAPILLARY
TUBE
BB063
(a) Device 317 Basic Air-Fuel Bleed Components
082 QUILLED HOLE
RETURN TUBE
(b) Device 317 Component Installation
Figure 4-36. DEVICE 317 CARBURETOR MODIFICATION WITH VACUUM ADVANCE
DISCONNECT INSTALLATION (DEVELOPER PHOTO)
4-133
-------
TO
FUEL BOWL
EXPANSION
CHAMBER-
^VACUUM
jS^ DIFFUSION
DEVICE
-GULP
VALVE
DISTRIBUTOR
VACUUM
VALVE
TO INTAKE MANIFOLD
Figure 4-37. DEVICE 317 CARBURETOR MODIFICATION WITH VACUUM ADVANCE
DISCONNECT: PRINCIPAL COMPONENTS (DEVELOPER SKETCH)
4-134
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Table 4-72. DEVICE 317 EMISSION TEST RESULTS REPORTED BY DEVELOPER
TEST
CONDITION
HC (PPM)
CO (%)
NO (PPM)
NUMBER
OF TESTS
1963 Cadillac (1970 Federal Test Procedure - Reference 15)
Without Device
With Device
Percent Reduction
332
321
3.3
2.55
2.31
9
1259
608
52
1
1
1967 Cadillac (1970 Federal Test Procedure)
Without Device
With Device
Without Device
With Device
Without Device
With Device
Percent Reduction
410
272
503
264
509
334
32
1.38 1
2.13
4.46
2.27
2.71
1.91
22
1245
590
665
474
600
790
35
1
1
1
1
1
1
3 sets
1967 Cadillac - California Air Resources Board Project 189 (7-Mode Hot Start)
With Device
With Device
306
284
1.8
1.5
470
862
1
1
4.4.5.4 Reliability
The developer has driven over 30,000 miles with the device installed without any
adjustment requirements or any noticeable change in vehicle performance. Consider-
ing that the device consists, essentially, of a vacuum line and a simple spring-ball
valve, it is estimated that its reliability should exceed 75,000 MMBTF.
Analysis indicates the possibility of a critical secondary failure mode (primary
failure mode not related to the device), which is discussed in paragraph 4.4.5.6.
4.4.5.5 Maintainability
Routine maintenance would include air-fuel ratio adjustment and inspection for any
plugged fuel source, as indicated by a rough running engine at idle. A further
maintenance requirement would be to inspect and clean the gulp valve when necessary.
It is assumed that the valve would require cleaning no more frequently than air fil-
ters require cleaning (12,000-mile intervals under average driving conditions) and
that cleaning could be accomplished within 10 minutes. Overall MMBM should be
12,000 miles, with 0.2-hour MTTM.
4-135
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4.4.5.6 Driveability and Safety
Driveability data supplied by the developer indicates no adverse problems for this
device provided that engine timing and air-fuel ratio are set correctly.
In the event the carburetor float bowl shutoff valve failed in the open position
and no fluid check valve is incorporated in the vacuum line, raw gasoline could be
pumped into the intake manifold and constitute a serious fire hazard. The condition
could be induced, also, by improper installation of the device causing the carburetor
float to jam either continuously or periodically.
4.4.5.7 Installation Description
The installation of this device consists in drilling a hole in the carburetor fuel
bowl cover so that a capillary tube can be inserted, replacing the primary metering
jets in the carburetor, mounting the expansion chamber on the bracket installed to
the rear of the carburetor, connecting hose to the carburetor base, and tightening
all connections. Adjustment of the engine consists in setting the timing, idle rpm,
air-fuel ratio (15:1), and the choke (one notch rich from factory specifications).
The developer states that prior to device installation, the engine must be properly
tuned and all adjustments set to factory specifications. Piston rings and valves
must be in good shape by checking the compression before installation or the device
will not perform to its best advantage.
In addition, the developer estimated that installation of the device would take
approximately one-half hour. Table 4-73, presenting a more detailed description of
the installation procedure, indicates that .0.75 hour might be required. This table
also identifies tools and special equipment required. Installation can be accom-
plished in a normally equipped repair shop by the average mechanic.
4.4.5.8 Initial and Recurring Costs
The developer estimated that the retail cost of the device installed will be $19.95.
Table 4-74 summarizes the installation costs. From the information available, it is
estimated that the cost for installing this device, including material would be $23.32.
4.4.5.9 Feasibility Summary
There appear to be some inherent safety hazards with the device, but they could be
avoided by refinements in design as noted in the safety analysis.
The average emission reductions reported by the developer for Device 317 were 32
percent for HC, 22 percent for CO, and 35 percent for NOx on the 1967 Cadillac tests.
The 1963 Cadillac tests showed a reduction of 52 percent in NOx, 3 percent in HC, and
9 percent in CO. Based on these data from the developer, Device 317 may have some
technical feasibility for control of HC and NOx, provided that the correct combination
of the device installation, the change in the main circuit carburetor jets, the ad-
justment of the gulp valve, and the timing of the engine can be established and
maintained.
4-136
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Table 4-73. DEVICE 317 CARBURETOR MODIFICATION WITH VACUUM ADVANCE
DISCONNECT INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1
2
3
4
5
6
7
8
9
10
11
12
Remove carburetor cover. Drill 0.082
inch hole in cover so as to clear
float assembly.
Install primary metering jet or jets
included in kit.
Reinstall carburetor cover with new
gasket.
Insert capillary tube in the 0.082
inch hole drilled in the cover, push-
ing it all the way to the bottom,
pull it back up 1/4 inch. Bend tube
over top of carburetor so as to clear
choke assembly.
Install evaporation chamber to rear
of carburetor with bracket from kit.
Install capillary tube assembly to
evaporation chamber and tighten
securely.
Remove PCV hose from carburetor base
and insert the vacuum T with short
hose and clamps from it.
Install PCV hose and clamp on vacuum
T.
Install short piece of 3/16-inch hose
from kit from small outlet of vacuum
T to small pipe on decel valve of the
evaporation chamber.
Start motor and adjust timing and
idle rpm.
Set carburetor air-fuel ratio at 15:1.
Set choke one notch rich from factory
specifications .
TOOLS, EQUIPMENT,
AND FACILITIES
a. Hand tools
b. Electric drill
a. Hand tools
b. Metering jets
a. Hand tools
b. Gasket
Capillary tube
a. Hand tools
b. Evaporation chamber
Hand tools
a. Hand tools
b. Vacuum T- fit ting
c. Hose
d. Clamps
Hand tools
Hose
Engine analyzer
Engine analyzer
Hand tools
Total Time
TIME
(MIN. )
10
6
1
1
3
2
3
2
2
3
9
3
0.75 hr
4-137
-------
Table 4-74. DEVICE 317 CARBURETOR MODIFICATION WITH VACUUM ADVANCE
DISCONNECT INSTALLATION COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Metering jets
b. Expansion
chamber
c. Vacuum T-fittin
a. Gasket
b. Capillary tube
c. Hose
d. Clamps
I Table 4-73
LABOR HOURS OR
ITEM QUANTITY
3
0.50 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Labor
1. Device
components
Clean and adjust
every 12,000 miles
(refer to para-
graph 4.4.5.6)
0.2 hr every
12,000 miles @
$12.50 per hour
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
13.95
(Included above)
6.25
3.12
$23.32
10.00
$10.00
$33.32
4-138
-------
4.5 TURBOCHARGED ENGINE - RETROFIT SUBTYPE 1.2.5
Only one approach of this type was found during the retrofit study. Turbocharging
should improve vehicle performance by increasing the volumetric efficiency of the
engine.
4.5.1 Device 100; Turbocharger
Although the retrofit developer did not respond to the retrofit data survey, infor-
mation on this approach to vehicle exhaust emission control was obtained from an
EPA test report (Reference 99).
The vehicle tested was a 1971 Volkswagen equipped with a turbocharger retrofit
package that consisted of a new exhaust system, a revised heater system, and minor
changes to the fuel, oil, and vacuum lines. The turbocharger operated off exhaust
gas taken from the exhaust pipe in front of the muffler. Intake air to the turbo-
charger was ducted from the standard air filter and from the turbocharger to the
carburetor venturi inlet. An electric fuel pump provided the fuel pressure re-
quired during high boost operation.
The vehicle was a standard production model VW with a four-speed manual transmission
and 96-CID, air-cooled, opposed-four-cylinder engine.
Table 4-75 summarizes the emission test results obtained with the 1972 Federal
Test Procedure. The EPA report noted that the stock vehicle emissions of the test
car were equivalent to other VW's tested. The report also noted that it was not
known whether the slight reduction shown for the turbocharged vehicle is due to the
device or to lean carburetion.
Table 4-75. DEVICE 100 TURBOCHARGER EMISSION TEST RESULTS
(REFERENCE 99) (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
3.5
3.0
14
CO
41
36
12
NOx
2.5
2.3
8
(1) Results obtained using the 1972 Federal Test Pro-
cedure (Reference 3) and lean idle carburetor
tuning. One test with and without device.
(2) 1971 Volkswagen (described in text)
Acceleration tests were also run by EPA on the test car. The results showed an
improvement in acceleration of over 2 seconds from 0-60 mph for the turbocharged
vehicle compared to the stock vehicle. From 50-80 mph, the acceleration time for
the turbocharged car was about 10 seconds less, or a 30 percent improvement over
stock.
4-139
-------
The EPA report concluded that the turbocharger does not adversely affect emission
levels (pr.operly installed and adjusted), but does improve vehicle performance.
Based on the EPA exhaust emission results, it would appear that the device would
not provide sufficient emission reduction effectiveness to classify it as a
reasonable retrofit method for used car exhaust emission control.
4-140
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4.6 FUEL INJECTION - RETROFIT SUBTYPE 1.2.6
Fuel injection as a method for controlling vehicle exhaust emissions may provide
improved distribution, vaporization, and diffusion of the air-fuel mixture with
resulting improvement in combustion and fewer pollutant byproducts. Only one
example of this approach was found in the retrofit survey. Volkswagen currently
uses electronically controlled fuel injection in some models to meet emission
standards.
4.6.1 Device 22; Electronic Fuel Injection
The developer did not respond to the retrofit data survey, but limited information
was obtained from an EPA test report (Reference 100). The test vehicle was a Ford
Thunderbird completely converted to electronically controlled fuel injection; there-
fore no exhaust emissions data could be obtained for the test vehicle without fuel
injection. The engine was tuned for minimum exhaust emissions with little consider-
ation for driveability.
Table 4-76 presents the results of the emission tests reported in Reference 100.
This reference indicated that the performance and driveability were adversely
affected.
Table 4-76. DEVICE 22 ELECTRONIC FUEL INJECTION EMISSION TEST
RESULTS REPORTED BY EPA (REFERENCE 100) (1)
TEST
PROCEDURE
HC
GM/MI
CO
GM/MI
CO 2
GM/MI
OXIDES OF NITROGEN (GM/MI)
(SALTZMAN)
(NOx BOX)
(INFRARED)
LA4 (2)
9 x 7 (3)
FTP (4)
10.8 5.4
4.3 5.7
2.3 2.3
50 50
34 60
21 22
916 899
746 748
(5)
1.2 1.5
1.9 2.0
— (5)
3.1 2.5
2.3 2.4
(5)
(5)
(5)
1.6 1.5
(1) Ford Thunderbird test vehicle (model year unknown), 427-CID engine.
(2) CVS tests using LA4-S3 driving schedule (1972 Federal Test Procedure -
Reference 3).
(3) Closed, constant volume sampling technique using 9 repeats of Federal
emissions test cycle (9 CVS) - Reference 16.
(4) Standard 1970 Federal Test Procedure
(5) No data reported ( ).
4-141
-------
Acceleration tests were performed using a stock Thunderbird for comparison, with
both vehicles carrying a 350-pound passenger load. Table 4-77 shows the average
results of two runs with each vehicle in opposite directions along the same course.
The retrofitted vehicle was faster only on the 0-60-mph run. There was objection-
able hesitation on tip-in and surging on cruise with this vehicle. The overall
driveability was rated "commercially unacceptable."
This was a limited evaluation of fuel injection as a vehicle exhaust emission con-
trol method, and it should not be considered as an evaluation of Device 22 for
retrofit application.
Table 4-77. DEVICE 22 ELECTRONIC FUEL INJECTION
ACCELERATION RESULTS
0-60 mph
20-50 mph
50-80 mph
DEVICE 22 T-BIRD
(SEC)
10.6
7.3
13.0
STANDARD T-BIRD
(SEC)
10.8
5.5
9.0
4-142
-------
0 - IGNITION
CONTROL SYSTEMS
-------
SECTION. 5
GROUP 1 RETROFIT METHOD DESCRIPTIONS:
TYPE 1.3- IGNITION CONTROL SYSTEMS
The approach taken with this group of devices is to control exhaust emissions
through modifications to the ignition system. Two methods are used in this ap-
proach: (1) ignition spark timing modification, in which the timing advance is
controlled; (2) ignition spark modification, in which the actual firing of the
spark plug is controlled. Seven devices incorporating these methods were found
to be either under development or in production. These devices are identified in
Table 5-1.
Table 5-1. TYPE 1.3 IGNITION CONTROL SYSTEM RETROFIT DEVICES
IGNITION TIMING MODIFICATION - SUBTYPE 1.
DEVICE NO.
69 (2)
175 (2)(3)
3.1
NOMENCLATURE
Electronic-Controlled Vacuum Advance Disconnect and Carburetor
Lean Idle Modification
Ignition Timing Modification with Lean Idle
IGNITION SPARK MODIFICATION - SUBTYPE 1.3
23 (1)
95 (1)
259
268
269
Electronic Ignition Unit
Ignition Spark Modification
Photocell-Controlled Ignition System
Capacitive Discharge Ignition
Ignition Timing and Spark Modification
Adjustment
.2
(1) Previously tested by EPA.
(2) Tested under the retrofit method study program.
(3) Accredited for retrofit use in California.
Two of these devices had been tested previously by EPA. Data on the others were
obtained from the developer, except that Devices 69 and 175 were also tested as
part of the retrofit study program.
5-1
-------
Ignition timing modification in the form of retarded spark timing has been found
to be an effective control for used car emissions of NOx; and, when used in com-
bination with lean idle mixture, an effective control for all three pollutants
from used cars (Reference 120). The emission control principles of modifying the
ignition spark have not been defined in literature known to date. Spark modifica-
tions have been used in the past as a means of engine performance improvement for
high compression, high rpm engines.
5-2
-------
5.1 IGNITION TIMING MODIFICATION - RETROFIT SUBTYPE 1.3.1
Ignition timing is a significant factor in effective exhaust emission control.
Retarding ignition timing at idle tends to reduce exhaust emissions in two ways:
1. With retarded timing, exhaust gas temperatures are higher,
thereby promoting additional burning of carbon monoxide and
hydrocarbons in the exhaust manifold. Since combustion in the
cylinder occurs later in the cycle, the peak combustion tem-
peratures occurring in the cylinders are reduced, inhibiting
the formation of NOx.
2. Retarded timing requires a slightly larger throttle opening
(increased fuel and airflow) to obtain desired idle speed.
The larger throttle opening results in better charge mixing
and combustion at idle, thus decreasing the amount of CO and
HC pollutant byproduct. The increased idle speed limits intake
manifold vacuum on decelerations reducing HC and providing a
more stable idle for lean mixtures (Reference 120).
The techniques used to retard timing for optimum emission control vary. General-
ly, it is desirable to have retard during idle, and full vacuum advance during
closed throttle deceleration. These characteristics can be obtained either
with vacuum systems incorporating both advance and retard capabilities, or with
electronic sensing of engine speed or load which disconnects the distributor
vacuum advance whenever spark retarded operation is required. Two retrofit de-
vices incorporating ignition timing modification are described in this section.
5.1.1 Device 69; Electronic-Controlled Vacuum Advance Disconnect and Carburetor
Lean Idle Modification
Device 69 is an ignition timing advance and idle mixture modification system.
It incorporates a method of idle air-fuel mixture adjustment and an electronic
method of monitoring and adjusting the distributor vacuum advance system. The
objective of this device is to reduce emissions at idle and low speed operation
through these methods based on the theory that:
1. Ere-1967 cars have carburetors which are adjusted for over-
enrichment during idle and low engine speed, and a leaner
air-fuel ratio can be achieved that both reduces HC and CO
emissions while keeping driveability acceptable.
2. Retarding the spark reduces peak temperatures and NOx emissions,
and extends the burning period into the exhaust system to
further reduce CO and HC emissions.
3. Engine speed rather than vehicle speed is a better criterion
for controlling the decision to retard ignition timing.
The device is in a prototype evaluation status. According to the developer,
35 prototype electronic spark control units have been manufactured and tests
have been performed on about 24 different vehicles. He also has developed a
special lean mixture screw assembly that has been provided for three different
5-3
-------
test cars. An alternative approach to controlling the mixture, already used on
production cars, is to adjust, secure, and seal the factory-installed carburetor
idle mixture adjustment screw.
5.1.1.1 Physical Description
Figure 5-1 shows a prototype electronic unit, which is approximately 4.5 inches
long, 3 inches wide, and 2 inches high, excepting the mounting flange. The
vacuum advance control valve body is approximately 1.5 inches on a side. The
valve assembly is approximately 1 by 2-1/2 by 2-1/2 inches overall, including
mounting bracket, electrical connections and tube fittings.
The developer's system layout drawing indicates that the lean mixture screw as-
sembly, which replaces each of the standard idle mixture screws, extends about
2 inches from the carburetor body. The system also includes an engine tempera-
ture sensor, approximately % inch in diameter. The remainder of the system in-
stallation comprises the wiring and vacuum advance hoses (the latter replacing
tubing which connects the carburetor and distributor in the production vehicle
configuration).
5.1.1.2 Functional Description
This system's function is to optimize the emission characteristics at low engine
speeds by both air-fuel mixture adjustment and ignition timing control. The
idle mixture is adjusted to an air-fuel ratio which provides acceptable emission
levels and acceptable low speed engine performance for engine speeds from 1,600
rpm to idle. This is accomplished by making an initial adjustment at slow idle,
and then trimming the adjustment at 1,500 rpm.
Figure 5-2 is a functional diagram of the ignition timing control, and identi-
fies most of the hardware involved in this device. The electronic control
unit, or "logic" as it is denoted by the developer, accepts data from three
sources, the principal source being the ignition coil. The electronic unit con-
nects to the low voltage side of the coil where it obtains both power to function,
and the pulsed signal proportional in rate to engine rpm. The logic functions to
sense whether the engine is indicating greater or less than 1,600 rpm.
The second data source is the brake light switch, which is used to identify periods
of rapid deceleration. The third data source is a thermistor (temperature sensing
device) to sense engine over-temperature condition. The developer states that in
production units the sensor will be installed in the electronic control unit, and
that the unit installation instruction will call for mounting to the radiator.
The logic decision (the function of the electronic unit) will be that if engine
rpm is less than 1,600 rpm or the brake switch is actuated and the engine has not
overheated, the vehicle vacuum advance system will be bypassed through the
normally open bleed tube of a solenoid valve installed in the distributor vacuum
line. If engine rpm is greater than 1,600 rpm and the driver is not applying
brakes, the valve is energized, closing the bleed tube and opening the distri-
butor vacuum line to the carburetor (manifold inlet) vacuum source. An engine
overheat condition will also result in a logic decision to energize the valve.
The brake switch connection is considered optional and would be connected in
accordance with the installation instructions for a specific vehicle.
5-4
-------
ELECTRONIC
CONTROL
UNIT
ELECTRICAL
CONNECTOR
VACUUM ADVANCE
DISCONNECT
SOLENOID VALVE
BB058
(a) Device 69 Components
VACUUM ADVANCE
DISCONNECT
SOLENOID VALVE
ELECTRONIC
CONTROL
UNIT
BB053
(b) Device 69 COMPONENT INSTALLATION
Figure 5-1. DEVICE 69 ELECTRONIC-CONTROLLED VACUUM ADVANCE DISCONNECT
WITH CARBURETOR LEAN IDLE MODIFICATION
5-5
-------
TO CARBURETOR
SOLENOID
VALVE
n
BRAKE SWITCH
ELECTRONIC CONTROL UNIT
T
inl
COIL
THERMISTOR SIGNAL
FOR ENGINE OVERHEAT
(INSTALLED IN ELECTRONIC CONTROL UNIT)
Figure 5-2. DEVICE 69 ELECTRONIC-CONTROLLED VACUUM ADVANCE DISCONNECT
FUNCTIONAL SCHEMATIC (DEVELOPER SKETCH)
5-6
-------
5.1.1.3 Performance Characteristics
Table 5-2 summarizes the results of emission tests 'performed in the retrofit study
program. Overall, the device appeared to improve the HC, CO and NOx emission re^
duction characteristics without severe impact on other vehicle performance charac-
teristics. There were variations in vehicle driveability during the tests, but
usually very little, and some of which may be attributed to the test vehicle.
Fuel economy degraded 15 to 20 percent on two vehicles and improved over 20 per-
cent on the third. The impact of the device on fuel economy cannot be conclu^
sively determined due to the small number of tests.
5.1.1.4 Reliability
The developer stated a device reliability of 50,000 MMBTF. No partial failure mode
is identifiable that could occur prior to the estimated MMBTF.
In the event the solenoid fails such that the vacuum advance is continuously in-
operative and/or the thermistor fails, engine overheating could occur.
Table 5-2. DEVICE 69 ELECTRON1C-CONTROLLED VACUUM ADVANCE DISCONNECT
AND CARBURETOR LEAN IDLE MODIFICATION EMISSION REDUCTION
AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Plymouth 318
Without Device
With Device
Percent Reduction
1965 Chevrolet 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reduction
Mean Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS /MILE
HC
5.49
3.34
39.2
5.28
3.83
27.5
8.00
5.55
30.6
32.4
CO
69.55
48.59
30.1
62.86
39.23
37.6
88.37
70.68
20.0
29.2
NOx
5.14
3.49
32.1
3.37
3.56
-5.6
3.49
1.86
46.7
24.4
FUEL
MILES/
GALLON
13.0
11.9
8.4
13.2
11.4
14.0
10.9
13.2
-21.4
0
(1) Emission results obtained by Olson Laboratories in tests performed under
Contract 68-04-0038 using 1972 Federal Test Procedure (Reference 3).
Fuel consumption was measured during these tests.
5-7
-------
5.1.1.5 Maintainability
The developer recommends standard 12-month or 12,000-MMBM service cycle, including
inspection of the solenoid and lean mixture screw, the solenoid operation, and
the electronic controller. The device should be tested for actuation of the
solenoid at the appropriate engine rpm, at which point the solenoid operability
can be verified.
It would be desirable if the device had test points to assess the condition of
the thermistor, which senses radiator temperature. If the brake light option is
part of the configuration, its operability should be verified also., It is esti-
mated that periodic maintenance attributable to the device can be performed within
20 minutes (0.3 hr MTTM). !
5.1.1.6 Driveability and Safety
This device was tested for driveability on three cars during the retrofit study
program. Tests were run on Cars 3, 4, and 5. Table 5-3 summarizes the drive-
ability results of these tests.
Table 5-3. DEVICE 69 DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CID
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1
(1)
CAR NO. 2
(1)
CAR NO. 3
Increased stall
during cold
start decelera-
tion
Increased hesi-
tation during
cold start
acceleration
Increased from
12.7 to 13.lt
Decreased from
26.1 to 22.U
CAR NO. 4
Increased stall
during cold
start decelera-
tion
Increased hesi-
tation during
cold start ac-
celeration; in-
creased cranking
time during hot
start; decreased
detonation during
hot start cruise
Decreased from
11.9 to 11.6
Increased from
22.3 to 2U.6
CAR NO. 5
No effect
Increased start.
attempts during
cold start; in-
creased rough
idle during
cold start idle
Decreased from
9-1 to 9.0
Increased from
26.5 to 31-8
CAR NO. 6
(1)
No significant change overall (Reference Table 5-2)
(1) Device 69 wag not tested on these vehicles.
5-8
-------
During the period of these tests, Car 4 had an intermittently bad starter solenoid
and the starting problems encountered might have been induced by this defect. In
addition, Car 4 had a tendency toward detonation at all times when the hot start
tests were run. This problem may or may not be due to the installation of the
device. Similarly, Car 3 exhibited a tendency toward hesitation caused by carbu-
retor settings and the problem encountered in these tests may or may not be due
to the installation of the device.
There appear to be no safety hazards with the device in operation on a vehicle.
5.1.1.7 Installation Description
The installation of this device consists in replacing the existing idle adjusting
screw in the carburetor with a special lean mixture screw, installing a spark
retard thermistor on the upper radiator reservoir tank, installing a solenoid
valve in the vacuum spark advance line, installing the electronic controller, and
connecting the wires from the device to the solenoid and coil. Adjustments con-
sist in setting engine idle rpm, adjusting air-fuel ratio, and setting the igni-
tion timing. The developer estimated that retail price for the complete kit
would be less than $50 and that the installation could be made in less than one
hour by a qualified mechanic.
Table 5-4 presents a detailed description of the installation requirements. In-
stallation can be accomplished in a normally equipped garage by the average
mechanic. From the information available, it is estimated that the total cost of
this installation, including material, would be $62.50.
Table 5-4. DEVICE 69 ELECTRONIC-CONTROLLED VACUUM ADVANCE DISCONNECT
AND CARBURETOR LEAN IDLE MODIFICATION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MIN.)
1. Remove the existing idle adjusting screw
from the carburetor and replace it with
the lean mixture screw (2 for dual- and
four-barrel carburetors)
2. Adjust idle speed to 600 rpm in drive for
automatic transmissions and to 700 rpm in
neutral for standard transmissions
3. Adjust the air-fuel ratio to 14:1 or to
1.5% CO at idle
4. Adjust the air-fuel ratio to 16:1 at
1500 rpm
5. Install the spark retard thermistor on
the upper radiator reservoir tank using
pressure-sensitive tape on epoxy
a. Hand tools
b. Lean mixture screw
Tachometer
Engine analyzer
Engine analyzer
a. Hand tools
b. Spark retard device
c. Tape or epoxy
4
4
3
5-9
-------
Table 5-4. DEVICE 69 ELECTRONIC-CONTROLLED VACUUM ADVANCE DISCONNECT
AND CARBURETOR LEAN IDLE MODIFICATION INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
6. Install the solenoid valve in the vacuum
spark advance line between the carburetor
and the distributor
7. Install the electronic controller and con-
nect the electrical leads from the device
to the solenoid valve and to the ignition
coil
8. Set the ignition timing to the manufac-
turer's specifications
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Solenoid valve
Hand tools
Engine analyzer
Total Time
TIME
(MIN.)
15
15
12
1 hr
5.1.1.8 Initial and Recurring Costs
Table 5-5 itemizes the initial and recurring costs for this device over a 50,000-
mile service life.
5.1.1.9 Feasibility Summary
Device 69 appears to be technically feasible and has effective exhaust emission
reduction. The fail-safe aspects should bear further considerations from a point
of view of device failure modes and their impact on the vehicle. The developer
stated that simple changes can be made to accommodate any desired failure mode
characteristics.
The installation and adjustment requirements and the costs appear to be reason-
able for this type of device, assuming that fuel consumption does not increase.
The basic device concept should facilitate design and manufacture for reliability,
and the developer's initial-cost estimate of less than $50 per kit seems valid.
5-10
-------
Table 5-5. DEVICE 69 ELECTRON1C-CONTROLLED VACUUM ADVANCE DISCONNECT
AND CARBURETOR LEAN IDLE MODIFICATION INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Lean mixture
screw for car-
buretor
b. Spark retard
device
c. Solenoid valve
Pressure-
sensitive tape
or epoxy
Table 5-4
Table 5-4
LABOR HOURS OR
ITEM QUANTITY
0.75 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Labor
1. Inspection
Refer to paragraph
5.1.1.5
0.33 hr every 12,000
miles at $12.50/hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
50.00
(Included
in above)
9.38
3.12
62 . 50
16.68
16 . 68
79.18
5-11
-------
5.1.2 Device 175; Ignition Timing Modification with Lean Idle Adjustment
This device is designed to control HC and NO emissions by means of electronic con-
trol of engine ignition timing. CO is controlled by adjusting the carburetor idle
mixture to a lean setting. Ignition control is regulated in two ways: (1) elec-
tronic regulation of the distributor signal, and (2) regulation of the distributor
vacuum advance mechanism. Both means'of regulation act to retard the basic timing.
The device consists of an ignition control assembly which is attached to the fender
well under the vehicle hood.
Device 175 has been certified for installation on pre-1966 used cars in California
by the California Air Resources Board (Reference 78). The device was one of four
representative retrofit devices tested during the retrofit study on used cars at
both the Olson, Anaheim, California, and Taylor, Michigan, test facilities.
5.1.2.1 Physical Description
The device control system includes the following electronic circuits and components:
1. A solenoid actuated valve which connects or disconnects the dis-
tributor vacuum advance.
2. An ignition circuit which regulates the distributor point signal
to a retarded condition at vehicle speeds below 35 mph.
3. A sequencing circuit and switch which senses vehicle speed and
controls the regulation provided by the first two items.
The device has two hose connections which attach to the carburetor distributor
vacuum port and distributor vacuum advance chamber. Three wire connections are
made: (1) one wire connects between the distributor points and the device, (2)
a second wire connects from the device to the distributor terminal on the coil,
and (3) a third wire connects between the device and the battery terminal on
the coil. Figure 5-3 shows the electronic control module installed.
5.1.2.2 Functional Description
The following is quoted from developer's functional definition for Device 175:
"The system is designed to control HC and NO emissions by means
of electronic control of engine ignition timing. CO is con-
trolled by means of a carburetor adjustment technique. The
basic function of the control unit is to regulate the ignition
spark advance and sequence the regulation according to vehicle
operating modes. The spark advance is regulated in two ways:
(1) electronic regulation of the distributor ignition signal
and (2) regulation of the distributor vacuum advance mechan-
ism. Both means of regulation act to retard the basic timing.
"Electronic regulation of the distributor ignition signal is
accomplished by means of an electronic circuit within the con-
trol unit. Electrical power is supplied to the unit through
one of the wires in the unit electrical cable. This wire
connects to the vehicle electrical system at the ignition
coil. The wire from the distributor points which normally
5-12
-------
DEVICE 175
CONTROL MODULE
Figure 5-3. DEVICE 175 ELECTRONIC CONTROL MODULE INSTALLED ON FENDER WELL
connects to the ignition coil, is disconnected and attached
to the second wire in the control unit electrical cable. In
operation, the distributor point signal, when routed to the
control unit, is regulated by the electronic circuit and
then routed back to the ignition system through the third
wire which is connected to the ignition coil. The regula-
tion in the ignition point signal causes the ignition tim-
ing to be retarded which effects a reduction in HC and NO
emissions. The amount of regulation desired is adjusted
by means of a switch within the control unit. This switch
is set by the mechanic when the unit is installed. The
distributor vacuum advance is regulated by means of an elec-
tronically controlled solenoid within the control unit.
This solenoid is connected to the carburetor and distri-
butor vacuum advance mechanism by the two rubber hoses on
the control unit. In operation, the solenoid disconnects
the vacuum advance from the carburetor causing the ignition
timing to be retarded which also affects a reduction in HC
and NO emissions.
"The ignition spark advance regulation, when coupled with the
carburetor adjustment procedure, results in a further reduc-
tion in HC. The carburetor adjustment procedure which reduces
CO also reduces HC emissions. The procedure is to adjust idle
speed and mixture. The idle speed is increased 50 to 75 rpm
above manufacturer's specifications and the mixture is adjusted
for best lean idle conditions. The lean mixture tends to reduce
5-13
-------
HC and the higher idle rpm reduces HC during deceleration
modes.
"In addition to regulating the ignition spark advance, a
sequencing system is provided in the control unit. The
function of the sequencing system is to control the time
at which regulation occurs. The purpose of sequencing
the timing regulation is to prevent idle overtemperature
conditions and maintain fuel economy and drive quality.
A sequencing control switch is also located in the con-
trol unit with the regulator switch, and adjusted at
time of installation. In operation, the timing regula-
tion is sequenced to allow full vacuum advance at idle
and low speed engine operation, which eliminates high
engine temperature and reduced fuel economy during pro-
longed periods of idle and creep speed conditions (traffic
jams, etc.). At high speed operation (above approximately
35 mph) the sequencing restores the ignition spark advance
timing to its normal operating condition, thereby maintain-
ing acceptable fuel economy and drive quality."
5.1.2.3 Performance Characteristics
Table 5-6 presents a summary of performance data based on information submitted
by the developer. Table 5-7 presents emission data measured during the retrofit
study test program. The device shows consistent effectiveness in decreasing CO
and NOx emissions, with less benefit in HC reduction. Gasoline mileage is 10%
less on the average.
Table 5-6. DEVICE 175 IGNITION TIMING MODIFICATION WITH LEAN IDLE ADJUSTMENT
EMISSION TEST RESULTS SUBMITTED BY DEVELOPER
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT
HC (PPM)
696 (1)
235 (2)
66
CO (%)
3.25 (1)
1.50 (2)
53
NOx (PPM)
1,170 (1)
538 (2)
54
(1) 7-cycle, 7-mode hot start average 17 used cars.
(2) 7-cycle, 7-mode cold start average of 17 used cars at start of ac-
creditation program. HC, CO, and NOx values for four cars at end
of 25,000 miles were 224 ppm, 1.54 percent, and 533 ppm, respectively.
5-14
-------
Table 5-7. DEVICE 175 IGNITION TIMING MODIFICATION WITH LEAN IDLE ADJUSTMENT
EMISSION REDUCTION AND FUEL CONSUMPTION PERFORMANCE (1)
VEHICLE
YEAR/MAKE/CID
1965 Chev 194
Without Device
With Device
Percent Reduction
1965 Ford 289
Without Device
With Device
Percent Reduction
1965 Ply 318
Without Device
With Device
Percent Reduction
1965 Chev 327
Without Device
With Device
Percent Reduction
1965 Ford 390
Without Device
With Device
Percent Reduction
1961 Chev 283
Without Device
With Device
Percent Reduction
ANAHEIM TEST RESULTS
POLLUTANT GRAMS /MILE
HC
10.67
9.17
14.1
10.55
7.06
33.1
6.70
6.38
4.8
8.35
10.10
-21.0
5.57
6.09
(2)
CO
71.56
63.41
11.4
133.27
104.58
21.5
75.96
69.77
8.1
111.73
122.66
-9.8
(2)
98.01
(2)
NOx
2.20
1.24
43.6
3.00
1.71
43.0
1.95
1.66
14.9
2.19
1.42
35.2
1.29
1.34
(2)
FUEL
GALLON
(2)
14.78
(2)
11.57
9.87
15.0
14.24
13.69
4.0
11.57
9.74
16.0
(2)
(2)
(2)
Pooled Mean
Percent Reduction (3) HC 19.2
TAYLOR TEST RESULTS
POLLUTANT GRAMS /MILE
HC
3.69
3.07
16.8
4.04
2.97
26.5
4.68 5.18
3.79 3.11
19.0 40.0
3.43
2.59
24.5
4.36
2.89
33.7
CO
57.16
13.43
76.5
56.10
11.96
78.7
40.82 46.82
15.89 12.45
61.1 73.4
50.91
12.87
74.7
38.52
12.70
67.0'
NOx
3.87
1.68
56.6
3.79
2.18
42.5
3.82 5.03
1.66 2.83
56.5 42.8
2.34
2.27
3.0
2.88
1.89
34.4
FUEL
MILES/
GALLON
14.00
13.22
6.0
12.60
13.22
-5.1
14.24 16.12
11.60 12.00
18.8 26
12.15
13.00
-7.0
13.22
10.60
20.0
CO 46.3 NOx 37.2 Fuel ' 10
(1) Emission results obtained by Olson Laboratories in tests performed under Contract 68-04-0038
using 1972 Federal Test Procedure (Reference 3). Fuel consumption Was measured during these
tests.
(2) Test data invalid.
(3) Anaheim and Taylor results combined.
5-15
-------
5.1.2.4 Reliability
The developer claimed a reliability of 75,000 mean-miles-before-total-failure
(MMBTF) and has performed extensive road testing of the system. No partial
failure modes which could occur prior to the estimated MMBTF were identifiable.
The system contains 63 electronic components and a solenoid actuated valve. The
primary solenoid failure mode is wear-out, which should not occur prior to 75,000
miles if components are properly selected. It appears that the developer's esti-
mate of reliability is reasonable.
In the event the solenoid valve fails such that the distributor vacuum advance is
continuously inoperative, engine overheating could occur.
5.1.2.5 Maintainability
No maintenance apparently is required on the system other than to perform an in-
spection, during routine vehicle maintenance, to assure that the unit is function-
ing. Repair is not possible. In the event of failure, removal and replacement
with a new unit is required. It is estimated by the developer that the replace-
ment time would be 0.75 hour.
5.1.2.6 Driveability and Safety
Device 175 was tested for driveability at the Olson Laboratories, Anaheim,
California and Taylor, Michigan, test facilities. Table 5-8 summarizes the
driveability results of these tests.
During the performance of tests with Car 1, it was discovered that the ignition
points were not closing properly since the dwell angle was too small. The results
obtained were probably not due to the device. A second test run was made and there
was no effect on the driveability.
The device showed 10% less gasoline mileage on the average. This would impact
recurring costs adversely as noted in Table 5-10.
5.1.2.7 Installation Description
The installation of this device consists in mounting the control unit on the fender
well in the engine compartment, connecting the wires to the distributor and battery,
and connecting the vacuum advance. Adjustment of the device consists in adjusting
switches inside the cover plate of the control unit. Adjustment of the engine con-
sists in setting idle speed 50 to 75 rpm over manufacturer's specifications, and
adjusting idle mixture for best lean idle conditions.
Table 5-9 provides a description of the installation requirements, installation
would require a qualified automotive mechanic and tuneup equipment.
5.1.2.8 Initial and Recurring Costs
Table 5-10 provides a summary of the estimated costs. From the information avail-
able, it is estimated that the total cost of this installation, including material,
would be about $44.50.
5-16
-------
Table 5-8. DEVICE 175 DRIVEABILITY TEST RESULTS
DRIVEABILITY
CHARACTERISTICS
CRITICAL
DRIVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
CRITICAL
DRiVEABILITY
GENERAL
DRIVEABILITY
0-60 MPH
ACCELERATION
TIME
(SECONDS)
60-40 MPH
DECELERATION
TIME
(SECONDS)
GAS MILEAGE
PER GALLON
1965 CHEV.
194 CID
1965 FORD
289 CID
1965 PLY.
318 CID
1965 CHEV.
327 CID
1965 FORD
390 CIO
1961 CHEV.
283 CID
ANAHEIM, CALIF., DRIVEABILITY TEST RESULTS
CAR NO. 1
No effect
Increased surge
on hot start
acceleration;
increased hesi-
tation on cold
start accelera-
tion
Decreased from
19.8 to 15.1»
Decreased from
19-5 to 17-8
CAR NO. 2 _j
(I)
(1)
(O
(U
CAR NO. 3
No effect
No effect
Decreased from
IS. 5 to 11.5
Decreased from
25-5 to 22.3
CAR NO. 4
No effect
No effect
Increased from
11.0 to 12.2
Decreased from
23-2 to 20.7
CAR NO. 5
No effect
No effect
Increased from
8.8 to 9-2
Decreased from
22 to 18.5
CAR NO. 6
Increased stall
during cold
test accelera-
tion.
Increased
stumble during
cold test
acceleration
Decreased from
16.6 to 16.1
Ho data
5-7)
TAYLOR, MICH., DRIVEABILITY TEST RESULTS
CAB HO. 16
No effect
Increase in
hesitation on
acceleration
for both hot
and cold start
phases.
Increased from
12.3 to 15. .5
Increased from
22.9 to 23.3
CAR NO. 8
Car stalled on
cold start
acceleration -
rough idle
for both hot
and cold start
tests
Increase in
cranking time
for hot start
and decreased
for cold start
Increased from
11. T to 17.7
Increased from
20.7 to 21.6
CAR NO. 9
Car stalled on
cold start
No change on
driveability
Increased from
12.9 to 13.6
Increased from
21.8 to 23.2
CAR NO. 10
No effect
Increase in
cranking time
and stumble
on accelera-
tion
Increased from
10.2 to 11.0
Increased from
21.1 to 2>t.7
CAR NO. 11
Car stalled on
cold start -
detonation on
hot start
acceleration
Stretchiness
on hot start
Increased from
9-7 to 10.2
Increased from
21.0 to 22.2
CAR NO. 12
No effect
Increase in
• hesitation
and stumble
Increased from
12.3 to 12.6
Increased from
25.0 to 28.1
Average decrease of 9.7 percent (Reference Table 5-7)
(1) Device 175 was not tested on this vehicle.
5-17
-------
Table 5-9. DEVICE 175 INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Using engine analyzer, verify -that
engine is operating within manu-
facturer specifications, adjust as
required.
2. Install control unit on fender wall
or other readily accessible location
in engine compartment using two
sheet metal screws.
3. Remove distributor point signal wire
from distributor terminal on coil and
connect to control unit red wire.
4. Connect control unit green wire to
distributor terminal on coil.
5. Connect control unit block wire to
battery terminal on coil.
6. Connect control unit red vacuum hose
to carburetor vacuum.
7. Connect control unit blue vacuum
hose to distributor vacuum advance.
8. Remove control unit cover plate.
9. Adjust switches per adjustment table
located on inside of cover plate.
10. Reinstall cover plate.
11. Adjust idle speed to 50-75 rpm over
manufacturer's specifications.
12. Adjust idle mixture for best lean
idle conditions (approximately 1.5
percent CO)
TOOLS, EQUIPMENT
AND FACILITIES
Engine analyzer
a. Electric drill
b. Hand tools
c. Sheet metal screws
d. Control unit
Wire
Wire
Wire
Vacuum hose
Vacuum hose
Hand tools
Hand tools
Hand tools
Engine analyzer
Engine analyzer
Total Time
TIME
(MIN. )
15
10
2
2
1
2
1
1
10
1
3
12
1 hr
5-18
-------
Table 5-10. DEVICE 175 INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
50,000-Mile
Recurring Cost:
Material
1. Fuel
DESCRIPTION
Control unit
a. Sheet metal
screws
b. Electric wire
c. Vacuum hose
Table 5-9
Table 5-9
10 average increase
in fuel consumption
(refer to Table 5-8)
LABOR HOURS OR
ITEM QUANTITY
0.5 hr
0.5 hr
Total Initial Cost
400^gallon fuel in-
crease x $0.35 per
gallon over 50,000
miles (1)
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
32.00
(Included
in above)
6.25
6.25
44.50
140.00
140.00
154.50
(1) Based on an assumed national average of 10,000 miles per year at 12.5 mpg
5.1.2.9 Feasibility Summary
Device 175 should serve adequately in the retrofit device class of ignition timing
modifications. The study results indicate that the device is effective in con-
trolling CO and NOx emissions, with relatively less effectiveness in controlling
HC. This device has demonstrated overall technical and economic feasibility by
meeting the standards for used car certification in California. The developer
reported that manufacture of the device has been initiated on a mass-production
basis.
The developer also reported that lower cost versions of the device are being de-
veloped for special control applications to selected pollutants.
5-19
-------
5.2 IGNITION SPARK MODIFICATION - RETROFIT SUBTYPE 1.3.2
This group of devices attempts to reduce emissions by modifying the strength of the
ignition spark. Based on information reviewed during the retrofit study, there is
no apparent relationship between the spark strength and resulting emissions.
One device reviewed in this section incorporates a capacitive discharge ignition
with no modification of spark timing. The capacitive ignition provides an extra-
ordinarily high secondary voltage for a duration which is somewhat shorter than
that obtained with a conventional ignition.
Another device reviewed in this section uses a photocell-controlled ignition system
that is claimed to increase the duration of the spark at the spark plug, thereby
reducing emissions.
A capacitive discharge system in general requires electronic circuits which perform
the following functions:
1. A high voltage current generator to charge the capacitor
2. A transistorized switching element
3. A synchronizing circuit which triggers the switching. (This
function is provided by the distributor points.)
In general, capacitive discharge ignition provides a much more rapid and much
higher voltage ignition spark than can be obtained with a conventional ignition
system. Good ignition spark is obtained even when distributor points and spark
plugs are in a degraded condition that would cause excessive misfires; however,
no relationship between spark strength and emissions is known to exist.
Capacitive discharge ignition is obtained by inducing a high voltage in the coil
secondary winding by discharging a capacitor charged to approximately 200 volts
through the coil primary. The capacitor is discharged through a transistor switch
for which control voltage is applied by the normal primary signal from the distrib-
utor. When the primary points open, control voltage is removed from the transistor
switch which causes it to flip closed, permitting the charged capacitor to discharge
through the coil primary windings. A short duration, 200-volt spike is delivered
to the coil primary, inducing a short high-voltage secondary voltage. The capaci-
tor is recharged during the period the distributor points are closed.
5-21
-------
5.2.1 Device 23; Electronic Ignition Unit
Although the manufacturer of this device did not respond to the retrofit data
survey questionnaire, limited evaluation was possible on the basis of a HEW/NAPCA
exhaust emission test report (Reference 81). The HEW/NAPCA tests were performed
to evaluate the device for its retrofit potential.
The device attaches to both sides of the ignition coil, as specified by the device
manufacturer. The test vehicle was apparently already equipped with a Ford retro-
fit kit. The device was tested in accordance with the 1970 and 1972 Federal Test
Procedures (References 15 and 3). The results obtained with the 1972 procedure
are summarized in Table 5-11.
Table 5-11. DEVICE 23 ELECTRONIC IGNITION UNIT EMISSION TEST
RESULTS REPORTED BY HEW/NAPCA (REFERENCE 81) (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
6.51
6.32
2.9
CO
93.81
109.08
-16.3
NOx
2.14
3.33
-56.0
(1) One 1972 Federal Test Procedure with and without
Device 23 installed on a 1963 Ford Galaxie 289-CID
with automatic transmission.
5-22
-------
5.2.2 Device 95; Ignition Spark Modification
This device is a commercial product that is marketed as a vehicle economy and
performance improver. The device has been tested on two occasions by HEW/NAPCA,
with results indicating that the device has no effectiveness for controlling exhaust
emissions (References 82 and 83).
5.2.2.1 Physical Description
The device fits between the distributor cap and the spark plug wires and is claimed
to "...precondition the gases in the nonfiring cylinders."
5.2.2.2 Functional Description
The device was described by the developer as follows (Reference 82):
"Using the principle of electromagnetic induction,
the circuits of the (device) tap electrostatic
energy from the firing spark. This energy is directed
to the nonfiring cylinders, where it bombards the fuel
molecules with radiation, preparing the mixture for
more complete combustion."
5.2.2.3 Performance Characteristics
The emission reduction characteristics of this device are summarized in Tables 5-12
and 5-13, based on emission data obtained from the referenced reports.
Table 5-12. DEVICE 95 IGNITION SPARK MODIFICATION EMISSION TEST RESULTS
(REFERENCE 83) (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
1.30
1.38
-6
CO
16.0
17.5
-9
NOx
4.80
4.55
6
(1) Average of two cold-start and two hot-start tests
using the 1970 Federal Test Procedures (Reference
15). The cold-start tests were run before and
after accumulation of 250 miles with the device
installed.
(2) EPA 1971 Ford with 351-CID engine,air conditioning
and automatic transmission.
5-23
-------
Table 5-13. DEVICE 95 EMISSION TEST RESULTS
(REFERENCE 82) (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
6.0
7.6
-26.7
CO
92
108
-17.4
NOx
1.6
2.1
-31.3
(1) Results of one test with and without device,
using 1972 Federal Test Procedure (Reference 3).
(2) 1963 Chevrolet Impala vith 283-CID engine.
5.2.2.4 Feasibility Summary
The developer did not provide information on which to base an evaluation of the
device's reliability, maintainability, driveability, safety, installation, or costs.
Based on the HEW/NAPCA test data it appears that this device would not be effective
in reducing HC, CO, or NOx exhaust emissions. The device therefore appears to be
infeasible for emission control application.
5-24
-------
5.2.3 Device 259: Photocell-Controlled Ignition System
Device 259 is an ignition spark modification retrofit method that increases the
duration of the ignition spark at the spark plug. The concept appears to be that
a longer spark duration may increase combustion efficiency, with attendant emission
reduction.
A photocell system is used in Device 259 to enable the spark to be prolonged. The
photocell replaces the conventional mechanically actuated breaker points.
Device 259 is in a prototype developmental status. Fifteen prototype units have
been made, and 10 installed on vehicles. Approximately 300,000 miles of operation
have been accumulated, but no testing has been performed to determine if emissions
are reduced.
5.2.3.1 Physical Description
The principal components of Device 259 for a four-cylinder ignition system are shown
in Figure 5-4. The system consists basically of an amplifier, a photocell and light
source, and a shadow disk. The shadow disk, bulb, and photocell are installed in
the conventional distributor in place of the standard breaker point assembly. The
shadow disk is a circular metal plate, sized to the distributor and with cutout
sections which allow the photocell to be energized.
STANDARD
DISTRIBUTOR
AMPLIFIER
COVER
Figure 5-4. DEVICE 259 PHOTOCELL-CONTROLLED IGNITION SYSTEM COMPONENTS
(4-CYLINDER IGNITION SYSTEM)
5-25
-------
The photocell and bulb are standard commercial components. The amplifier is a
prototype designed specifically for the requirements of this system by the developer.
It incorporates printed circuit boards.
5.2.3.2 Functional Description
The system provides longer spark duration by replacing the standard breaker points
of the conventional distributor with a photocell and shadow disk. The function
of the breaker points is performed by the photocell, under control of the shadow
disk.
As shown in Figure 5-4, the shadow disk attaches to the distributor rotor with
the photocell on one side and the light source on the other. As the disk rotates,
light to the photocell is pulsed in accordance with the cutout pattern in the disk.
The duration of each pulse, and hence the spark duration, is determined by the arc
length of the cutouts.
The electrical schematic of the Device 259 system is shown in Figure 5-5. The
following excerpt from the developer's test report (Reference 85) defines the
basic functional relationships:
"The optimum spark duration can only be achieved when the spark
gap in the distribution cap is replaced by a sliding contact (to
lengthen the contact time and hence spark duration). It will have
to be determined if this optimum spark duration is actually reouired.
Once the now remaining unburned gases are burned by an extended spark,
a further spark extension is superfluous. It may be pointed out that
the development of a sliding contact in the distributor cap (would)
be somewhat costly. Contact wear may reduce the dependability.
"The spark duration times of a conventional ignition system . . . are
considerably below the optimum time. The (Device 259) ignition system
provides a maximum spark duration time of 3.8 msec which, at higher
rpm, is only limited by the optimum time.
"(With Device 259), the points of the distributor have been replaced
by a shadow disk. A 5-volt bulb, rated 60,000 hours - the average
life of an automobile engine when driven for 100,000 miles at 35
miles per hour would reouire an operating time of 2,857 hours - is
connected to the 12-volt battery over a voltage drop resistor. To
protect the bulb from overvoltage, a zener diode is connected in
parallel to the bulb.
"When the ignition switch is turned on, the 5-volt bulb burns con-
tinuously, shining on a highly sensitive photocell, which has a 50-
microsecond switching time.
"The shadow disk, mounted on the distributor shaft, moves between
the bulb and the photocell. The photocell resistance changes
from 2,000 ohms (light) to infinite (dark) and provides the bias
for a transistorized amplifier. The output current of the ampli-
fier flows over a resistor into the primary winding of the igni-
tion coil. When connected to resistive load, the amplifier
produces a square current wave.
5-26
-------
886
12VBAHERY
Figure 5-5. DEVICE 259 PHOTOCELL-CONTROLLED IGNITION SYSTEM ELECTRICAL SCHEMATIC
(DEVELOPER SKETCH)
"The spark is initiated when light hits the photocell and con-
tinues until the spark energy is used up. The current demand
under operating conditions is approximately A A average."
5.2.3.3 Performance Characteristics
No emission test data was provided for this device by the developer. The developer's
test report provided the following performance summary with respect to potential
emission reduction:
"A test car equipped with the (Device 259) ignition system was
driven 30,000 miles. When the engine heads were removed, no
carbon deposit could be detected. We therefore conclude that
the combustion, when using our ignition system, i? somewhat
improved.
"The point eouipped ignition systems have distinct disadvantages,
one of which is a short spark duration. It stands to reason that
the unburned gases, which are contained in the exhaust smog, have
a better chance of burning when the spark duration is extended." .
5.2.3.4 Reliability
The developer claimed in his test report that the elimination of the point system
and the application of a rotating shadow disk should provide the ultimate in depend-
ability, because the system has no mechanical wear.
5-27
-------
Data were not obtainable by which to determine a specific mean-miles-before-total-
failure (MMBTF). With a reliable amplifier, the service life of the system could
far exceed 75,000 miles. For the amplifier, components would have to be selected
for the use environment. For example, use of silicon semiconductors rated to 125°C
would be essential to meet reliability requirements, if the amplifier is mounted in
the engine compartment.
Particularly critical to reliability is the selection of the light source and the
photocell detector, because the failure of either could render the system totally
inoperative in potentially hazardous driving modes. Acceptable reliability of
photocells and light bulbs have not been verified for an automotive ignition use
environment; however, acceptable reliabilities for silicon solid-state devices
have been verified for:
(1) Light emitting diodes for the light source
(2) Photo field effect transistors for the detector
These devices are readily available in production quantities.
5.2.3.5 Maintainability
In the event of system failure, the average motorist or an automotive repair shop
could remove and replace the system. It is expected that routine maintenance would
be performed on the distributor, such as inspection, cleaning, and lubrication, in
accordance with standard procedures and at the intervals prescribed by the vehicle
manufacturer (25,000 MMBM) . No additional maintenance peculiar to the Device 259
ignition modification appears to be required. Elimination of the breaker points,
as the system would enable, would preclude the need for normal breaker point tuneup
maintenance. Thus, some money would be saved by use of the device.
5.2.3.6 Driveability and Safety
The developer has tested the device on several vehicles as part of his development
effort. He reported that no apparent driveability problems were observed in these
tests. Catastrophic failures of the amplifier, photocell, and light could render
the vehicle inoperative under hazardous circumstances; therefore, the final design
and selection of components and methods of manufacture are critical to safety.
5.2.3.7 Installation Description
Installation of this device consists in installing an amplifier and coil in the
ignition system and replacing the rotor, points, and condenser in the distributor
with a photocell unit and shadow disc. The adjustment required after installation
is to set the ignition timing. Figure 5-6 shows a typical installation.
The developer stated that the complete installation can be accomplished by the
average mechanically inclined car owner. The required material would be supplied
in a kit with installation instructions included. It would be necessary to buy
this kit to fit a specific model automobile and a specific ignition distributor.
An alternate method of accomplishing the installation would be to provide a modified
distributor in exchange for the distributor from the car.
5-28
-------
PHOTOCELL-
CONTROLLED
DISTRIBUTOR
BB124
Figure 5-6. DEVICE 259 PHOTOCELL CONTROLLED IGNITION SYSTEM TYPICAL INSTALLATION
The developer estimated one-half hour labor for installation and the cost of material
at approximately $50. This installation can be performed at the average service
station provided that the kit contains the proper sized parts for the specific ig-
tion distributor installed on the car. No special tools or test equipment are re-
quired. Table 5-14 describes the installation procedure.
5.2.3.8 Initial and Recurring Costs
Table 5-15 shows the costs associated with this device. Some recurring cost savings
would be obtained, due to the maintenance free operation of the device.
5.2.3.9 Feasibility Summary
Since no test data to substantiate the device's emission reduction capability have
been developed, the device's feasibility for emission control purposes is unknown.
5-29
-------
Table 5-14. DEVICE 259 PHOTOCELL-CONTROLLED IGNITION SYSTEM INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC/STATION ATTENDANT
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove distributor cap, leaving- spark
plug wires in place.
2. Observe position of rotor and remove
distributor.
3. Replace points and condenser by
adapter.
4. Replace rotor by rotor shadow disc
combination.
5. Reinstall distributor observing the
same rotor position.
6 . Replace distributor cap on
distributor.
7. Fasten the amplifier coil combi-
nation in the engine compartment
using two sheet metal screws.
8. Move spark plug wire from old coil to
new coil.
9. Connect cable from distributor into
amplifier.
10. Move plug wire from old coil to
amplifier.
11. Readjust ignition timing
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools
a. Hand tools
b . Adapter
a. Hand tools
b. Rotor shadow disc
Hand tools
Hand tools
a. Hand tools
b. Electric drill
c. Amplifier and
coil combination
Hand tools
a. Timing light
b. Hand tools
Total Time
TIME
(MIN.)
2
5
5
2
5
2
3
2
2
2
15
0.75 hr
5-30
-------
Table 5-15. DEVICE 259 PHOTOCELL-CONTROLLED IGNITION SYSTEM
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Amplifier
b. Coil
c. Adapter
d. Shadow disc
Sheet metal screws
Table 5-14
LABOR HOURS OR
ITEM QUANTITY
0.5 hr
0.25 hr
Total Initial Cost
50,000-Mile Recurring
Cost (Savings) : (1)
Material
1. Ignition
. Labor
2. Ignition parts
Breaker Points (1)
Replace and adjust
points (1)
4 pair of ignition
breaker points saved
by Device 259 @
$3.50/pair
0.5 hr x 4 replace-
ments @ $12.50/hr
Total Recurring Cost
Total Costs
COST
(DOLLARS)
50.00
6.25
3.12
59.37
-14.00
-25.00
-39.00
-20.37
(1) Indicates recurring cost savings due to material/labor no longer required.
5-31
-------
5.2.4 Device 268: Capacitive Discharge Ignition
The operational concept of this device, as claimed by the developer, is to provide
a higher-than-normal voltage spark so as to improve engine combustion, with resulting
benefits in engine power, fuel economy, and lower emissions.
Over 200,000 units of the device have been manufactured for production and retrofit
applications.
5.2.4.1 Physical Description
As shown in Figure 5-7, this device consists of an electronic assembly packaged in a
3- by 3- by 6-inch aluminum housing, and a power booster assembly of approximately
half that size. The electronic unit weighs approximately 1/2 pound. A pushbutton
switch on the side permits selection of either capacitive discharge or conventional
ignition.
BB194
Figure 5-7. DEVICE 268 CAPACITIVE DISCHARGE IGNITION
5.2.4.2 Functional Description
Figure 5-8 shows a basic schematic of the device. Capacitive discharge ignition is
obtained by inducing a high voltage in the coil secondary winding by means of a
capacitor charged to approximately 200 volts through the coil primary. The capaci-
tor is discharged through a transistor switch whose control voltage is applied by
the normal primary signal from the distributor. When the primary points open, con-
trol voltage is removed from the transistor switch which causes it to flip closed,
5-32
-------
HIGH TENSION WIRE
FROM IGNITION (SWITCH) if1 FROM DISTRIBUTER (POINTS)
RED
COIL
.WHITE~GREY-
- GREEN
Figure 5-8. DEVICE 268 CAPACITIVE DISCHARGE IGNITION SCHEMATIC
(DEVELOPER SKETCH)
permitting the charged capacitor to discharge through the coil primary windings.
A short duration, 200-volt spike is delivered to the coil primary, inducing a short
high-voltage secondary voltage. The capacitor is recharged during the period the
distributor points are closed.
5.2.4.3 Performance Characteristics
This device has been used mainly to improve ignition system operation in higher
performance engines. The manufacturer apparently has not determined whether the
device is effective for emission control. No data were reported on emission
characteristics, driveability, or fuel consumption. Based on electrical princi-
ples, a capacitive discharge could provide a more rapid, higher voltage spark
than a conventional system.
5.2.4.4 Reliability
The manufacturer estimated minimum device reliability at 250,000 miles failure. The
estimate was predicated upon field data and the manufacture and distribution of over
200,000 units. Examination of the device indicated that it contains about 40 stan-
dard electronic components and two specifically manufactured for the device: the
high voltage transformer and a wire-wound resistor. Provided all components are
selected for the use environment, particularly temperature, a 150,000-MMBTF should
be achieved with high confidence level.
5.2.4.5 Maintainability
No routine maintenance appears to be required. In the event of system failure, the
average motorist or automobile repair shop could remove and replace the system. It
is estimated that the removal and replacement could be accomplished in less than 45
minutes. The system has an integral switch to enable the use of the standard ig-
nition if required.
5.2.4.6 Driveability and Safety
Since 200,000 units of the device are in use on automobiles, this device apparently
has no adverse driveability effect that is unacceptable. It is not known whether
formal driveability tests have been performed. Failure of the system could result
in engine failure under potentially hazardous circumstances. It might be considered
desirable to install the system bypass switch in or under the dashboard for driver
accessibility. No other potential hazards have been identified provided the usual
precautions required when working around high voltages are observed during vehicle
maintenance.
5-33
-------
5.2.4.7 Installation Description
The installation of this device consists in installing the unit on the fender well
in the engine compartment away from hot sections of the engine, and connecting four
wires. Adjustment of the engine consists in increasing the spark plug gap and re-
adjusting the ignition timing at the distributor.
The developer estimated that one-half hour of labor would be required for installa-
tion. Table 5-16 itemizes the installation requirements, including tools and special
equipment. Installation can be accomplished in a normally equipped repair shop, by
the average mechanic or by the vehicle owner.
5.2.4.8 Initial and Recurring Cost
The developer reported that his device is sold through dealers at a retail cost of
$59.95. Table 5-17 summarizes the installation costs for this device. From the in-
formation available, it is estimated that the cost for installing this device, in-
cluding material would be $69.32. Since no maintenance is required, the device
would have no recurring cost.
5.2.4.9 Feasibility Summary
The ability of this device to reduce HC, CO, or NOx emissions would have to be
demonstrated before it could be considered for retrofit use to control vehicle
emissions. Except for reducing misfires as distributor points and plugs deteriorate,
no mechanism is known by which a stronger spark reduces emissions.
Table 5-16. DEVICE 268 CAPACITIVE DISCHARGE IGNITION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Install unit in engine compartment on
fender wall or other readily acces
sible location using sheet metal
screws, away from hot sections or
engine.
2 . Connect four wires
3 . Increase spark plug gap for maximum
effectiveness, or install new plugs
4. Readjust timing at distributor.
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill
b. Sheet metal screws
c. Device assembly
d. Hand tools
a. Hand tools
b. Wire
Hand tools
Engine analyzer
Total Time
TIME
(KEN.)
15
10
5
15
0.75 hr.
5-34
-------
Table 5-17. DEVIQE 268 CAPACJTIVE DISCHARGE IGNITION
INITIAL AND RECURRING COSTS (1)
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
t
i
Labor
1. Installation
2. Test and
adjust
DESCRIPTION
a. Sheet metal
screws
b. Electric wire
Table 5-16
LABOR HOURS OR
ITEM QUANTITY
0.50 hr
0,25 hr
(1) According to the developer this _ ,,.,.,„'
device has no recurring cost . T^al Initial Cost
COST
(DOLLARS)
59.95
6.25
3.12
$69.32
5-35
-------
5.2.5 Device 296: Ignition Timing and Spark Modification
According to the developer's data, this device combines longer spark duration with
retarded spark timing during acceleration. The retarded timing, which should have
the same effect as disconnecting the vacuum advance, allows the use of lower grade
gasoline with high compression engines.
5.2.5.1 Physical Description
As shown in Figure 5-9, Device 296 consists of two elements. The solid-state
elements mount in the engine compartment away from engine heat. The circuitry is
packaged in a plastic case about 2 inches in diameter and 4 inches long. It connects
to the ignition system through a four-wire connector which is wired to the distri-
butor, the coil primary circuit, and the battery. The device is wired to intercept
the ignition signal from the distributor.
5.2.5.2 Functional Description
Device 296 is a solid-state ignition control which provides a longer than normal pulse
to the automobile ignition coil at intervals controlled by the device, and that also
controls spark timing in relation to engine rpm. At idle, the pulse to the coil is
supplied at the normal time. As rpm increases, the timing pulse is delayed, in effect
retarding the spark. The spark timing is then linearly advanced by the device until
some point in the mid-rpm range, where the timing becomes the same as it would be
without the device.
The system contains a flip-flop circuit with special timing and sensing elements for
computing rpm. The circuit calculates the time for maximum combustion timing and
delivers a spark of longer duration than the conventional system.
5.2.5.3 Performance Characteristics
Table 5-18 summarizes the'results of tests performed on the device by the California
Air Resources Board (Reference 86).
The results indicate that the device has no significant effectiveness in reducing
exhaust emissions. The difference in emission values is within the range of normal
variation for test results.
5.2.5.4 Reliability
The device appears to contain about 18 standard electronic components, including a
semiconductor integrated circuit. Provided all components have been selected for
the use environment, particularly temperature, and properly rated in their circuit
use, the equivalent mean-miles-before-total-failure would exceed 75,000.
5.2.5.5 Maintainability
No routine maintenance, attributable to the device, is indicated. In the event of
device failure, the average motorist or automotive repair shop could remove and
replace the device.
5-36
-------
IGNITION TIMING •
AND SPARE
CONTROL UNIT
CONNECTOR
(a) Device 296 Components
BB060
BB052
(b) Device 296 Installation
Figure 5-9. DEVICE 259 IGNITION TIMING AND SPARK MODIFICATION
5-37
-------
TABLE 5-18. DEVICE 296 IGNITION TIMING AND SPARK MODIFICATION
EMISSION TEST RESULTS REPORTED BY DEVELOPER (REFERENCE 86) (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT
HC ppm
196
180
8
CO %
3.42
3.27
4
NOx ppm
279
290
-4
(1) One hot start, four-cycle California 7-mode test
(Reference 41) for each condition.
(2) 1965 Cadillac two-door hardtop, using standard
Indolene test fuel, with 429-CID engine.
5.2.5.6 Driveability and Safety
Since the device is being marketed for use on automobiles, it would appear that
there are no unacceptable driveability characteristics. The developer reported that
the device has no adverse effect on vehicle driveability, but no formal driveability
test data were provided. Failure of the device could result in engine failure under
hazardous circumstances. It might be considered desirable to install a bypass switch
in or under the dashboard for driver accessibility. Fuel costs could be reduced if
a change to regular or low-lead gas is made possible by use of the device.
5.2.5.7 Installation Description
The installation of Device 296 consists in mounting the ignition control unit on the
fender well in the engine compartment, and connecting the wiring to the coil, bat-
tery, points, and ground. It is estimated that installation of the complete system
should take about 15 minutes. Table 5-19 shows the installation requirements. In-
stallation can be accomplished in a normally equipped repair shop by the average
mechanic.
5.2.5.8 Initial and Recurring Costs
The developer estimated that the cost of the device would be $20. Table 5-20
summarizes the overall costs for this device. From the information available, it
is estimated that the cost for installation, including material, would be $23.12.
There are apparently no recurring costs.
5.2.5.9 Feasibility Summary
Based on the emission test data results of Table 5-18, it would appear that this
device would not be feasible for retrofit control of exhaust emissions; however,
more tests would be required to make a conclusive determination as to the effective-
ness of the device for a variety of used cars with the device in the optimum emis-
sion control configuration.
5-38
-------
Table 5-19. DEVICE 296 IGNITION TIMING AND SPARK MODIFICATION
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Install unit in engine compartment
on fender wall or other readily
accessible location using sheet
metal screws, away from hot sec-
tions of engine.
2. Connect wire from unit to battery.
3. Connect wire from unit to ground.
4. Connect wire from unit to coil.
5. Connect wire from unit to points.
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill
b. Sheet metal screws
c. Device
d. Hand tools
Hand tools
Hand tools
Hand tools
Hand tools
Total Time
TIME
(MIN.)
5
3
2
2
3
0.25 hr
Table 5-20. DEVICE 296 IGNITION TIMING AND SPARK MODIFICATION
INITIAL AND RECURRING COSTS (1)
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
DESCRIPTION
Transistor ignition
Sheet metal screws
LABOR HOURS OR
ITEM QUANTITY
0.25
(1) There are no recurring costs Total Initial Cost
indicated for this device.
COST
(DOLLARS)
20.00
(Included
in above)
3.12
23.12
5-39
-------
6 - FUEL
MODIFICATION SYSTEMS
-------
SECTION 6
GROUP 1 RETROFIT METHOD DESCRIPTIONS:
TYPE 1.4 - FUEL MODIFICATION
In Sections 3 through 5, descriptions are presented of retrofit exhaust-emission
control systems which either act upon the pollutant byproducts of combustion to
change their chemical composition to a nonpolluting form, or which modify the com-
bustion process to inhibit the formation of pollutants. Related to the latter is
the class of retrofit approaches described in this section. These approaches each
use the fuel as the means of controlling exhaust emissions. The intent in each case
is to inhibit the formation of pollutants during the combustion event in the engine
cylinder and, in some cases, to generate only pollutants of lesser reactivity and
hence of lesser photochemical smog potential.
These preventive or inhibitive approaches to exhaust emission control are imple-
mented in the fuel modification retrofit methods studied in one of three ways:
a. By changing the fuel type from gasoline to one which produces fewer, less
reactive pollutants.
b. By mixing additives with the gasoline normally used, so as to inhibit
pollutant formation.
c. By subjecting the gasoline normally used to an electromagnetic field, with
the intent of improving its combustibility and of generating fewer pol-
lutants. This method does not appear to be substantiated; however, it is
included to group some devices which refer to it specifically.
These approaches are reflected in the 12 retrofit devices listed in Table 6-1. Each
approach defined above constitutes a fuel modification subtype.
6.1 GAS CONVERSION - RETROFIT SUBTYPE 1.4.1
Half of the retrofit approaches studied in the fuel modification category were of
the gas conversion type. All but one of these gas conversions were of the gaseous
fuel type. The sole liquid fuel conversion was from gasoline to methanol (Device
464).
As discussed in Section 2, two gaseous fuels are being given consideration and study
by many agencies as feasible alternatives to gasoline. These fuels are liquified or
compressed natural gas (LNG and CNG) and liquified petroleum gas (LPG). These fuels
have an inherent advantage over gasoline for reduced emissions, because their chem-
ical composition contains less of the olefinic and aromatic compounds which are key
reactivity agents in the formation of smog. They also are capable of being operated
at higher air-fuel ratios than gasoline; and, because they are gaseous at normal
ambient temperatures, do not produce the high emissions characteristic of gasoline
during cold start engine operations (refer to Section 2, paragraph 2.4).
6-1
-------
Table 6-1. TYPE 1.4 FUEL MODIFICATION RETROFIT DEVICES
ALTERNATIVE GAS CONVERSION - SUBTYPE 1.4.1
DEVICE
NO.
52
459
460
461
464
466
NOMENCLATURE
LPG
LPG
Conversion
Conversion with Deceleration Unit
Compressed Natural Gas Dual-Fuel Conversion
LPG
Gas
Conversion with Exhaust Reactor Pulse Air Injection and Exhaust
Recirculation
Methanol Fuel Conversion with Catalytic Converter
LPG-Gasoline Dual Fuel Conversion
FUEL ADDITIVE - SUBTYPE 1.4.2
182
282
457
465
Fuel
and Oil Additives
LPG Gas Injection
Water Injection
Fuel
Additive
• FUEL CONDITIONER - SUBTYPE 1.4.3
36
279
Fuel
Fuel
Conditioning by Exposure to Electromagnetic Field
Conditioner
Thus gaseous fuels, by their chemical composition and physical properties, inherently
have combustion byproducts which are less polluting than gasoline. These same
characteristics enable the low-emission engine tuneup principles of high air-fuel
ratio and spark retard to be used with greater effectiveness in decreasing exhaust
gas CO, HC, and NOx. For example, emission tests reported in Reference 26 for CNG
and LPG, with the vehicle engine tuned to an air-fuel equivalence ratio of 1.12
(lean) and with no vacuum advance, resulted in CO, HC, and NOx emissions that were
less than the limits specified for 1973-74 new model vehicles in Reference 27 (1).
(1) Air-fuel equivalence ratio is equal to the air-fuel ratio of the mixture
divided by the stoichiometric air-fuel ratio of the mixture.
6-2
-------
While the retrofit approaches previously described used the engine as a means of
attaining emission decreases, gaseous fuels enable the other principal component of
the fuel-engine emission system - the fuel itself - to be used as a control. As
indicated by the retrofit devices described in this section, the combination of
both approaches offers lower emission reduction effectiveness, for the reciprocat-
ing engine as presently designed, than if used separately.
Besides their emission reduction potential, gaseous fuels appear to have other
advantages over gasoline. Both gaseous fuels generally cost less, and their
potential for economy of operation has attracted many people to their use, partic-
ularly industrial firms with large vehicle fleets, independent of emission reduc-
tion consideration. The low cost of natural gas is attributable to the regulation
of its well-head price by the Federal Power Commission (Reference 30). Natural
gas requires relative little processing for use and one of the products of such
processing is propane, the principal constituent of LPG. Besides being a by-
product of natural gas refining, propane is also a byproduct of crude oil refining.
In California, natural gas sells for 16-19C per 100 cubic feet, including road tax,
and LPG sells for approximately 25
-------
b. The relatively high cost of implementing their use, particularly
on a retrofit basis.
c. The requirements for special vehicle fuel tanks by which to contain
sufficient quantities of the gases so that vehicles can be operated
a reasonable distance without having to refuel.
d. The possibility of having to modify pre-1970 engines to prevent the
excessive valve seat wear that could result from the lack of lead
in gaseous fuels.
e. The possibility of performance degradation in older engines when
converted to a gaseous fuel.
f. The requirement that, once the natural gas and petroleum industries
have converted their processing facilities to support a higher
demand for gaseous fuel, the automotive industry would have to design
engines specifically for gaseous fuels, so as to provide for contin-
ued use of these fuels after their need for retrofit use have phased
out.
g. Safety problems.
These factors are discussed in the descriptions of gaseous fuel devices which
follow.
6-4
-------
6.1.1 Device 52; LPG Conversion
Device 52 is in mass production for use on light- and heavy-duty vehicles. The
device has been approved by the California Air Resources Board for use as an LPG
and dual-fuel (LPG and gasoline) conversion system for light-duty vehicles since
1969 on 1966 and subsequent vehicles (Reference 31). In July 1971, the device was
approved for natural gas conversions (Reference 32); and, concurrently, use was
extended to include all light and heavy duty vehicles (Reference 33). It is esti-
mated that approximately 350,000 conversions employing the device are in use in
California and that 20 percent of these are light duty vehicles (Reference 33).
6.1.1.1 Physical Description
Device 52 is produced in two configurations, one for natural gas or liquified
petroleum gas conversions and one for NG or LPG and gasoline conversions.(1)
These are the two basic types of gaseous fuel systems. The former is referred to
as the single-fuel system and the latter as the dual-fuel system. Incorporating
the single-fuel system, a vehicle can run only on natural or liquified petroleum
gas. Incorporating the dual-fuel system, a vehicle can run on either the gaseous
fuel to which it has been converted, or on gasoline.
Conversions of the single gaseous fuel type incorporate basically the same system
components. The physical characteristics of the principal components are described
below:
6.1.1.1.1 Fuel Tank. The fuel tank, though its function is simply to store fuel
for use by the engine, is the most expensive component of a gaseous fuel system,
as shown in paragraph 6.1.1.8. The chief cause of this high cost is that both
natural and petroleum gas have to be compressed before enough of either type can
be stored on a vehicle to enable it to travel distances comparable to a gasoline
fueled vehicle.
To store enough of either gas, it is necessary to compress them to the point where
they are in the liquid state.
Storage of liquified petroleum gas is relatively simpler than liquified or com-
pressed natural gas, which is discussed in paragraph 6.1.4. When pressurized,
propane the principal constituant of LPG, can be stored as a liquid between
-W+F, its boiling point, and 206F, beyond which it cannot be liquified under any
pressure. Under ambient temperature and at 160 psi, about 35 gallons of LPG can
be stored in two tandem tanks, one 12 by 14 by 42 inches and the other 10 by 14
by 42 inches, in a passenger car trunk. This will provide enough LPG fuel to
drive about 350 miles. The cost of a tank setup like this is about $165 (Refer-
ence 34).
(1) The manufacturer of Device 52 produces all system components but gaseous fuel
tanks and interconnecting lines. Gas fuel conversion systems are generally
integrated by firms which specialize in system installation, using components
from the various manufacturers in the gaseous fuel component field. Device
52 is described as an integrated system so as to examine the overall effect-
iveness and cost implications of gaseous fuel systems.
6-5
-------
LPG tanks are generally constructed of heavy-gauge steel or aluminum. They we'
an average of 3.5-4.5 pounds per gallon capacity. A 35-gallon tank when 80 percent
full may weigh 300 pounds even though LPG is lighter than gasoline (4.2 versus 6.5
Ib/gal). The tanks incorporate an outage valve to limit filling to 80 percent of
tank capacity so that there is room for the liquid to expand should the temperature
rise .
6.1.1.1.2 Fuel Filter and Shutoff Valve. This is a combination valve that
filters the fuel as it leaves the tank and that stops the flow of fuel when it
is not needed.
6.1.1.1.3 Liquid-Gas Converter.
a gaseous state.
This component converts liquified gas back to
6.1.1.1.4 Carburetor. The carburetor is the principal functional component of
a gaseous fuel system. Device 52 incorporates one of four different types of
carburetors depending on the type of gas conversion and the cubic inch displace-
ment of the engine o These are shown in Figure 6-1.
(A)
(B)
Figure 6-1. DEVICE 52 GASEOUS FUEL CARBURETOR TYPES
The applications of these carburetors are as follows:
a> Type A: Dual-fuel conversions for use of gasoline and LPG or gaso-
line and NG on engines of 250 CID and over.
b- Type B: LPG conversions on engines of 200-375 CID and under 140 CID,
c' Type C: LPG conversions on engines of 250 CID and over.
d. Type D: LPG conversions on engines of over 300 CID.
6.1.1.2 Functional Description
Figures ^-2 and 6-3 show the system integration of components for representative
single- and dual-fuel natural gas or liquified petroleum gas conversions. Except
6-6
-------
•©
(T) LP-GAS MOTOR FUEL TANK
(A) Filler valve (0) Vapor return valve
(C) 10% Outage valve (D) Vapor vent
(E) Relief valve (F) Vrrtt line to outside
Of vehicle (f.) lP.fi8% valve (H) LP-fias
high prr-s^ure hose linn (K) dtol gauge
(?) FILTER AND VACUUM FUEL
^ LOCK
Prevents flow of fuel when engine stops
with ignition switch on (H) LP'Gas Inlet line
(L) Connect s to intake manifotd vacuum
© CONVERTER
Two stage regulator and converter
(M) Water Inlet or outlet from engine
(Brass Fittings)
(P) Hand Primer (Q) Balance line
connection
(7) AIR CLEANER
Low profile de%ign, rtn-typo
(H) PCV Connection
(?) CARBURETOR *
• Accepted by California Air Resources
Board — Resolution No. 70-9A
(T) Idle adjustment screw (3) Balance line
(O CONTROL PANEL
(W) Push button primer switch
(V) 12 Volt tottery connection
Figure 6-2. DEVICE 52 SINGLE-FUEL SYSTEM DIAGRAM (REFERENCE 35)
©
U) LP-GAS MOTOR FUEL TANK
(A) F.ller valve (B) Vapor return valve
(C) 10% Outage valve (D) Vapor vent
(E) Relief valve (F) Vent line to outside
of vehicle (G) LP Gas valve (H) LP-Gas
high pressure hose line (K) Fuel gauge
(%} FUEL FILTER AND SOLENOID VALVE.
V-/ 12 VOLT
Control* 'low «l fuel
(T) LP GAS CONVERTER
Two ^t^Re ri-c.ulator nnrt cnnvoitet
(L) Waler inlnt or outli.'l Irom pnqme
cooling system (Use ems-, fit ling'.)
AIH CLCANEK*
Board — Hesolulion No. 70-9A
(M) PCV connection (N) Evaporative
control vent
(T) ADAPTER TO GASOLINE CARBURETOR
Supplied by Impco fi^ specified
(?) EXISTING GASOLINE CARBURETOR
SiratgtH or oUiet ad.ipl'rf d^dildbln
Opifdlf ''Oil canirni p,inci tost;''' J.A-I!( d
(H} VACUUM CONTROL SWITCH
(0) Connects to inl.ihp manifold vacuum
(R> Cnnn«:ls to LP-Gas solrnnit) hoi lino
(S) Connect;, to toggle switch hot ttnn
1 Q) CONTROL PANEL
wwimr n lo run on Gasoline (T) TORRIO
fuel control (U) Electric primer switch for
Impco converter (W) 12 vott battery
connection
Figure 6-3. DEVICE 52 DUAL-FUEL SYSTEM DIAGRAM (REFERENCE 36)
6-7
-------
for the fuel tank differences between the two gases, the systems operate much the
same. The boiloff valve required for LNG vaporization due to cryogenic tank heat
gain and the outage valve required to limit LPG tank filling are the principal
tank differences, other than for physical construction and configuration.
In each case the gaseous fuel is under pressure in the tank. Under this pressure
the LPG fuel flows in liquid form through the filter unit.(l) This unit combines two •
functions. Besides filtering the fuel to remove constaminants, it functions as a fuel loclj
to prevent fuel flow when the engine is off. In the single-fuel LPG system shown in Figure 6-2,
this function is controlled by intake manifold vacuum, such that when there is no
vacuum fuel flow is stopped. This prevents the possibility of fire should the
ignition switch be left on with the engine stopped or stalled. In the dual-fuel
system shown in Figure 6-3, the fuel lock function is controlled by means of the
electrically actuated solenoid. This form of fuel lock mechanization is used
with the dual-fuel system to facilitate changeover from gaseous to gasoline fuel
while the vehicle is in operation.
From the filter, the fuel, still in the compressed and cooled liquid state, flows
to the converter in the engine compartment. The converter performs the function
of a fuel pump, so on single-fuel conversions the fuel pump can be removed. The
converter consists of two diaphragm-actuated valves which, for safety purposes,
reduce the pressure of the liquid in stages. As the liquid pressure is reduced,
the liquid expands, rapidly absorbing heat, and converts to gaseous form. The
necessary heat is provided by circulating hot water through a water jacket in the
converter-regulator from the engine cooling system.
As shown in Figure 6-4, fuel enters the high pressure valve at tank pressure as a
liquid and is reduced to 1.5 psi in the expansion chambers. Conversion of the
liquid fuel to gas occurs in the expansion chambers which are heated by the hot
water from the engine. The now gaseous fuel passes through the secondary, or low-
pressure valve of the converter where the pressure is reduced slightly below at-
mospheric. From the low-pressure valve the fuel is drawn off through the regu-
lator gas outlet to the carburetor in proportion to the amount of intake manifold
vacuum.
As shown in Figure 6-5, the dual-fuel system functions the same way as the single-
fuel system, except that the carburetor for the dual-fuel system mounts on top of
the existing gasoline carburetor. With compressed natural gas, the converter is
not required, since the fuel is already in a gaseous state. For compressed
natural gas, a regulator is used to control the gas supply pressure to the car-
buretor .
The Device 52 carburetors (Figure 6-1) control the flow of fuel from the converter
to the combustion chamber on the basis of the amount of airflow through the car-
buretor. Figure 6-6 shows the principal parts of a representative carburetor
(Figure 6-1, Type C). The only moving parts are the butterfly valve and the com-
bined air measuring valve and air metering valve diaphragm system.
Actuation of the butterfly valve through the accelerator linkage causes air to be
drawn into the carburetor under intake manifold vacuum. The air measuring valve
is depressed in proportion to the amount of airflow. Since the gas meteriag valve
(1)
Compressed natural gas would be in the gaseous state throughout system flow.
6-8
-------
LIQUID IP GAS FUEL INLET... TANK PRESSURE
WiihiiMt mi (ml m thr (KidTlrT-n ciibl«; ihr |>
PRESSURE SEAT
BACK PRESSURE
FROM CARBURETOR
INSURES
POSITIVE LOCKOFF
MANUAL PRIMER
BLUE SPRING
HIOH PRESSURE DIAPHRAGM VENT
ATMOSPHERIC
VENT
OR BALANCE
CONNECTION
IDLE FUEL MIXTURE ADJUSTMENT SCREW
POWER FUEL MIXTURE ADJUSTMENT VALVE
VAPORIZED IP-GAS
I '/i INCH W/C NEGATIVE PRESSURE
LOW PRESSURE SEAT
tV fm-l rl-G1lllM tprillK TM* wrvn Itv vlmr IIIIKII.*!
•I llvr ftiMI l.lwl ml • givilllv nHnlrrt.*
VAPORIZED LP-GAS m IBS. PRESSURE
WATER CHAMBERS
EXPANSION CHAMBERS
NORMAL POSITION
CLOSED
Figure 6-4. DEVICE 52 SINGLE-FUEL SYSTEM CONVERTER AND
CARBURETOR DIAGRAM (REFERENCE 37)
LIQUID LP-GAS FUEL INLET...TANK PRESSURE
nr. Ihf
POWER FUEL MIXTURE ADJUSTMENT VALVE •
KMCTIV! ONI. »t Flfll IO«0
IDLE FUEL MIXTURE ADJUSTMENT SCREW
ificiwt ONI! »t mi into
FUEL MIXER VALVE SEAT
BACKPRESSURE RELIEF VALVE
BODEN WIRE LIFTER CAM
VAPORIZED IP-GAS
14 INCH W/C NEGATIVE PRESSURE
HIGH PRESSURE SEAT
BACK PRESSURE
FROM CARBURETOR
INSURES
I POSITIVE LOCKOFF
NORMAL POSITION
CLOSED
X
MANUAL PRIMER
GASOLINE CARBURETOR
POSITIVE CRANKCASE
HIGH PRESSURE
DIAPHRAGM VENT
VENTILATOR VALVE | —
CONNECTION i
ATMOSPHERIC
VENT OR
BALANCE
CONNECTION
LOW PRESSURE SEAT
Thi h™ pr.*..i... viKr l< h.'U m Ih,- ,l.«-n In
III., (m I n.|;ilhl..r splini: Thl. V rki t Ihr V1IIH- Ililltlliill
iv I)., fl.tll l-ml .HI I CJMlllm. ,jrlmnli»
ANT1-STALL DASHPOT
IDLE SPEED ADJUSTING SCREW
VAPORIZED LP-GAS Hi IBS. PRESSURE
WATER CHAMBERS
EXPANSION CHAMBERS
Figure 6-5. DEVICE 52 DUAL-FUEL SYSTEM CONVEETER AND
CARBURETOR DIAGRAM (REFERENCE 38)
6-9
-------
AIR INTAKE
DIAPHRAGM
VACUUM TRANSFER TUBE
VACUUM CHAMBER
IDLE ADJUSTMENT
NOT SHOWN
POWER MIXTURE
ADJUSTMENT
GAS INTAKE
DISTRIBUTION RING
ANTI VORTEX VANE
AIR MEASURING VALVE
GAS METERING VALVE
Figure 6-6. DEVICE 52 LPG CONVERSION REPRESENTATIVE
CARBURETOR (REFERENCE 37)
is attached directly to the air valve, it opens as the air valve depresses. At
maximum depression, the air valve forms a venturi and the air metering valve is
completely off its seat in the gas intake circuit. The maximum amount of fuel
that can enter this circuit is controlled by the power mixture adjustment, which
can only be set at wide open throttle, when the gas metering valve is fully un-
seated. Adjustment of this valve sets the air-fuel ratio from off-idle through wide
open throttle. Air-fuel ratio at idle is set separately through the idle adjust-
ment. The idle adjustment is effective up to approximately 900 rpm, after which
the air-fuel ratio determined by the power mixture adjustment becomes effective.
In between idle and wide open throttle, the gas metering valve also affects air-
fuel ratio, depending on its seating distance. Also the amount of fuel flow past the
valve when it is partially restricting flow can be varied by controlling the fuel
pressure. The air-fuel mixture can be leaned or richened in this way, particularly
between 20 and 70 percent of wide open throttle (Figure 6-7).
One of the advantages of gaseous fuels is that they can be operated at higher
air-fuel ratios than gasoline. (1) These higher ratios provide more oxygen
for the combustion event, and thus enable more complete combustion, with less CO
and HC byproduct. In recent tests of gaseous fuels, an air-fuel ratio of
approximately 21:1 was found to be the limit for acceptable driveability (Refer-
ence 26). Figure 6-7 shows the air-fuel ratio variations that can be obtained
by varying the fuel pressure at the carburetor inlet.
(1) Lean misfire limits of over 1.5 air-fuel equivalence ratio have been measured
for methane and propane, as compared with 1.3 for gasoline (Reference 30).
6-10
-------
GRAPH: Mixture Comparison At Light Loads — Full Load Mixtures Readjusted For Each Pressure
1050 B.T.U. Natural Gas (High Heat Value)
u< Idle 10%
20% 30% 40% 50% 60% 70% 80%
—> LOAD — PERCENTAGE OF AVAILABLE HORSEPOWER
90 % 1 00 %
Figure 6-7. DEVICE 52 VARIATION OF AIR-FUEL RATIO WITH FUEL PRESSURE
(ENGINE: FORD 352 CID WITH TYPE D - REFERENCE 37)
The carburetor functions of the single and dual-fuel systems shown in Figures 6-4
and 6-5 are basically the same. In the single-fuel carburetor, the air valve
is seated by spring pressure when the engine is not operating, closing off the
gas intake circuit. In the dual-fuel carburetor, the air valve is held shut by
a lock ring (actuated-by the Bowden Cable System) to prevent it from opening when
the engine is operated off the gasoline carburetor.
Since the fuel enters the carburetor in a gaseous state, no carburetor choke sys-
tem is required during cold start as with gasoline. The air valve and gas meter-
ing valve system admit the fuel mixture in direct proportion to engine demand.
6.1.1.3 . Performance Characteristics
Device 52 was tested for emission reduction performance by HEW/NAPCA with single-
fuel LPG systems installed on 10 Ford Falcons and 10 American Motors Rebels, all
1970 models, and on a 1968 Buick Skylark (Reference 38 and 39). The tests with
the Buick were performed with the engine in its as-received condition. Since the
LPG system was already installed on the Buick, it was not possible to obtain base-
line emission data.
In addition to having the LPG system installed, the Falcons and Rebels had the
distributor vacuum advance disconnected and the ignition timing set at top dead
center (TDC) at 600 rpm in drive. The Falcons were further modified to incorporate
hardened seat valves. (1) Table 6-3 presents the averages of the emission test
results obtained for these vehicles with the 1972 Federal Test Procedure.
(1) As noted in paragraph 6.1.1.4, the reliability of the average engine may de-
crease when converted from gasoline to gaseous fuel. The valve seats could be
affected adversely by this conversion because they are usually manufactured,
for the gasoline-fueled engine, out of metal that requires the lead in gasoline
as a lubricant to prevent recession of the seat during operation.
6-11
-------
Table 6-2. DEVICE 52 LPG CONVERSION EMISSION TEST RESULTS WITH 1968
BUICK SKYLARK (REFERENCE 38) (1)
VEHICLE
CONFIGURATION (2)
POLLUTANT (GM/MI)
HC
COLD
START
HOT
START
CO
COLD
START
HOT
START
NOx
COLD
START
HOT
START
Without Device
With Device
(3)
3.45
1.92
3.01
(3)
4.81
29.60
4.70
(3)
8.95
4.0
7.45
(1) Results obtained using the Federal 7-mode CVS Test Procedure (nine 7-
mode cycles). (Reference 16).
(2) 1968 Buick Skylark with automatic transmission and 350-CID engine
incorporating Device 52 Type A carburetor.
(3) No data; 1969 Surveillance Fleet Buick Skylark.
Table 6-3. DEVICE 52 LPG CONVERSION EMISSION TEST RESULTS WITH VACUUM ADVANCE
DISCONNECT AND RETARDED TIMING ON 1970 FALCONS AND REBELS (REFERENCE 39) (1)
VEHICLE
CONFIGURATION (2)
Without Device
Average Without
With Device
Average With
Percent Reduction
POLLUTANT (GM/MI)
HC
FALCONS
3.70
3
0.69
0
81
REBELS
2.67
.18
0.51
.60
.1
CO
FALCONS
15.99
19
1.76
2
REBELS
22.13
.06
3.89
.83
85.2
NO*
FALCONS
9.43
8
2.59
2
64
REBELS
6.85
.14
3.13
.86
.9
(1) Averages of 18 tests using the 1972 Federal Test Procedure
(Reference 3) and 9 of
each vehicle type.
(2a) 1970 Falcon with automatic transmission and 250-CID engine incorpor-
ating Device 52 Type B
single-fuel LPG carburetor and converter system.
Engine timing set for TDC at 600 rpm in drive (from manufacturer's
specification of 6 degrees BTDC at 550 rpm in drive) and vacuum advance
disconnected.
(2b) 1970 Rebel with automatic transmission and 232-CID engine incorporating
same LPG conversion, ignition timing and vacuum advance disconnect as
the Falcon (manufacturer's specifications
for Rebel ignition timing ie 3
degrees BTDC at 550 rpm in drive).
6-12
-------
Device 52 also has been tested by the California Air Resources Board, with the
results shown in Table 6-4. Table 6-4 indicates that emission reductions
with LPG conversions vary substantially from car to car, with no special emission
controls other than production controls installed. Table 6-3 indicates that with
the combination of LPG,vacuum advance disconnect, and retarded timing, emissions
are substantially decreased. This would indicate that the emission reductions are
more attributable to engine timing than to LPG. This indication accords with the
results of similar tests reported in Reference 26. In the Reference 26 test pro-
gram, emission levels of approximately 0.8 gm/mi HC, 3 gm/mi CO, and 1.3 gm/mi NOx
were obtained with LPG conversions, when the vacuum advance was disconnected and
an air-fuel ratio of approximately 17.5:1 was maintained.
Table 6-4. DEVICE 52 EMISSION TEST RESULTS WITH FORD
FAIRLANE AND MUSTANG (REFERENCE 40) (1)
VEHICLE
CONFIGURATION^)
Without Device
Average Without
With Device
Average With
Percent Reduction
POLLUTANT
HC
FAIRLANE
211(4)
(PPM)
MUSTANG(3)
256(5)
233.5
181
99
140
40
CO (%)
FAIRLANE
0.47(4)
0.
0.93
0.
MUSTANG(3)
0.55(5)
51
0.50
72
-41
NOx
FAIRLANE
1,131.5(4)
(PPM)
MUSTANG(3)
1,565(5)
1,348
1,056.0
1,858
1,457
-7
(1) Average of results obtained using four 7-mode hot-start cycles (Reference
41), except for Note (3).
(2) One 1968 Fair lane with Device 52. Type A dual-fuel LPG conversion and
standard engine modification type exhaust control system; and one 1968
Mustang with Device 52 Type B single-fuel LPG conversion and standard
engine modification exhaust control system.
(3) Average of two 7-mode
hot-start cycles.
(4) Averages with Basin Mix and Premium gasoline.
(5) Averages with Premium
gasoline .
The dependence of LPG emission performance on air-fuel ratio and spark advance is
shown by Figure 6-8. This figure is based on emissions data obtained from tests
on a 1970 Chevrolet with 350-CID engine, using three hot cycles of the California
7-cycle, 7-mode test procedure (Reference 41)., CO is affected only by air-fuel
ratio, decreasing as the increase in air enables more complete oxidation of carbon
monoxide to carbon dioxide. NOx decreases in proportion to-the-amount of spark
retard. HC tends to increase with leaner air-fuel ratio because of occasional
misfire at the leaner fuel mixtures, with consequent dumping of unburned hydrocar-
bons into the exhaust; however, the magnitude of HC increase is less with less
6-13
-------
rtiUVACUiW
1 c,
I /" \ HALF VACUUM
i /
/
i \ M VACUUM —
\ NO, -A BO
\ «S- ADO
\tc ----
°\ A- \
. Wv \ /*
:v^/\
/ \ n^-'^Ai t
v\
12 14 ~ 'r It 18 20
J
PATIC (15 JO ACCEL)
Figure 6-8. EFFECT OF AIR-FUEL RATIO AND SPARK ADVANCE ON LPG
EMISSIONS (REFERENCE 41)
spark advance, which provides the higher exhaust temperature necessary to oxidize
the unburned HC.
Table 6-2 indicates another performance characteristic of LPG, in the relatively
little difference between the cold and hot start emissions. The overall variation
between cold and hot start emissions for the three pollutants is approximately 10
percent. This is attributable to the gaseous state of LPG at the time it enters
the carburetor. Unlike gasoline, no cold-start enrichment of the air-fuel mixture
is required. Thus the mixture remains approximately constant for both cold and
hot engine operations. Data obtained in the Reference 26 test program corroborates
this indication that the LPG-converted vehicle has a low-emission advantage over a
gasoline fueled vehicle during warmup, because no fuel enrichment is required.
The manufacturer of Device 52 has had numerous emission tests performed to qualify
his gaseous fuel systems for the California exhaust emission standards. Since
1969, these tests have been performed in accordance with special California pro-
cedures for motor vehicles modified to use LPG or natural gas (Reference 45).
These procedures are basically the same as the 1970 Federal Test Procedure for
gasoline-fueled vehicles, except that for LPG (propane) the following factors are
applied to the calculation of the exhaust emissions:
a. Because of the reduced reactivity of propane emissions over those
of gasoline, a factor of 0.75 is applied to the measured NDIR hydro-
carbon values. This factor is based on the fewer olefin and
aromatic compounds present in propane than in gasoline. As noted in
Section 2, LPG exhaust emissions are less reactive than those of
6-14
-------
gasoline because of this difference in chemical composition, and
therefore cause less air pollution,
b. Because of the difference between propane and gasoline in their
carbon to hydrogen ratios and in their heating values (BTU/lb.),
a volume correction factor of 13 is used for propane in the exhaust
dilution calculation instead of 14»5 as for gasoline.
c. A deterioration factor of 1.0 is applied.
Using these factors, the Device 52 manufacturer reported emission test data as
shown in Table 6-5. The benefit of the revised test procedure by which these
data were obtained is shown by comparing the ppm and percent calculations of.the
Note (3) vehicle with the actual NDIR readings listed in Table 6-4.
Table 6-5. DEVICE 52 LPG CONVERSION EMISSION DATA OBTAINED BY CALIFORNIA
GASEOUS FUEL TEST PROCEDURE (REFERENCE 45) (1)
CARBUR-
ETOR
TYPE
A
A(3)
A
A(4)
B
B
C
C
C
D
D(5)
D
D
D
D
VEHICLE
YEAR MAKE MODEL CID
1965 Chev Impala 283
1968 Ford Fairlane 350
1971 Ford Pinto 120
(Same car with gasoline)
1971 Ford Pinto 120
1965 Chev Impala 283
1971 Ford Pinto 120
1965 Chev Impala 283
1965 Olds 88 425
1965 Olds 88 425
1965 Chev Impala 283
1965 Olds 88 425
1968 Pont (2) 400
1968 Ply (2) 383
1969 Chry (2) 440
1970 Chev (2) 350
POLLUTANT
HC
GM/MI PPM
1.20 (2)
1.70 134
0.54 (2)
1.80
0.70 (2)
1.40 (2)
0.49 (2)
1.50 (2)
0.90 61
0.83 (2) .
1.50 (2)
0.25 (2)
1.30 99
0.80 50
1.00 54
1.80 148
CO
GM/MI 7o
10.30 (2)
20.50 0.86
7.07 (2)
25.96
10.90 (2)
2.30 (2)
3.49 (2)
4.30 (2)
1.50 0.05
1.30 (2)
7.60 (2)
12,60 (2)
4.20 0.17
2.50 0.11
6.80 0.26
1.30 0.05
NOx
GM/MI PPM
1.10 (2)
3.80 970
0.85 (2)
3.49
1.30 (2)
0.80 (2)
0.79 (2)
0.60 (2)
1.20 282
1.20 (2)
0.80 (2)
1.10 (2)
2.00 491
1.30 392
1.70 392
2.10 554
(1) All vehicles were set to manufacturers specifications for spark advance and idle speed,
except Note (5). All vehicles except Note (3) had the heat risers disconnected and a
160F thermostat installed. All data obtained by independent test laboratory.
(2) Data not provided by manufacturer.
(3) Same car as in Table 6-4; no special tuning.
(4) With turbocharger.
(5) Spark retarded and 160-degree thermostat installed with heat risers disconnected.
6-15
-------
6.1.1.4 Reliability
The reliability of Device 52 depends mainly on the functional integrity of the
filter and fuel lock, the converter, and the carburetor„ These units (shown in
Figures 6-2 and 6-3) have been in use for 15 years as integrated LPG systems, and
have indicated high reliability. Under average vehicle use and maintenance, these
components have demonstrated reliability of more than 100,000 miles (Reference 34).
Device 52 systems have been used on police vehicles in 24-hour continuous patrol
service with no failures attributable to the LPG system over a period of 46,681
miles (Reference 29). The vehicles, one 1969 Ford Custom 500 with 428-CID engine
and one 1969 Dodge Coronet with 383-CID engine, are still in operation at this date
with no failure of the Device 52 Type D single-fuel LPG system having been
reported. Device 52 systems are currently in operation with 27,000 continuous
hours of failure-free use (Reference 33).
Although the Device 52 system itself has high reliability, the reliability of
engines converted to LPG use may be adversely affected if the engine is not in
good condition to start with,, The device manufacturer has found that a "poorly
performing engine converted to propane will only magnify its poor performance"
(Reference 42). Engines converted to LPG have been found to run cleaner because
of the lack of the deposits which build up on the pistons, rings, valves, and
cylinder heads of gasoline-fueled engines. When an older engine with heavy
deposits is converted to LPG, it loses these deposits and, if the rings and valves
are worn, may also degradate in performance because of an attendant decrease in
power (Reference 34).
Engine reliability is also affected by the possible increased wear imposed on
valve seats due to use of LPG. As noted in Reference 2, a number of studies have
shown that exhaust valve seat wear increases with the removal of lead additives.
Leaded fuels apparently provide high-temperature solid-film lubricants, in the
form of lead chlorobromide deposits, which reduce this wear, LPG is analogous to
unleaded fuel in this respect. With LPG there have been a number of cases in
which the valve seats recessed into the engine block (Reference 42)„ This has
occurred mainly on pre-1970 vehicles which were not designed to operate on unlead-
ed fuel (Reference 34)„ Modification of engines to incorporate harder valve seats
is offered as an option with LPG conversions, to prevent seat recession, as noted
in paragraph 6.1.1.8.
6.1.1.5 Maintainability
The manufacturer of Device 52 reported that the only maintenance required on the
LPG system is periodic inspection and cleaning of the fuel filter. If the propane
used conforms to Specification HD-5 (Reference 43), this filter should not have
to be replaced. Replacement cost reported by the developer is $2.00. Inspection
and cleaning time is approximately 0.25 hour.
Maintenance histories reported by the users of LPG indicate that a substantial
amount of money can be saved in vehicle maintenance costs by converting from gas-
oline to LPG (Reference 46). Because at ambient conditions it is naturally in a
gaseous state, LPG is thought to not have the washing effect that gasoline has on
the cylinder walls of an engine. If the lubricating oil on the cylinder wall is
not continually washed off, then the piston rings, being well lubricated, would
be expected to last longer. This is apparently the case with LPG. Furthermore,
6-16
-------
since the gaseous fuel does not run past the piston rings, as gasoline might, the
crankcase oil should not become diluted. Also, since the fuel burns more com-
pletely, there is less residue in the form of carbon scale and gum in the combus-
tion chamber to cause engine wear. Thus the combination of cleaner oil, cleaner
combustion, and tighter engine should provide longer engine life and less perfor-
mance degradation with mileage accumulation. Estimates as to how much engine life
is increased range from zero to 300 percent (Reference 46).
The maintainability advantages of LPG are documented in a number of reports
summarized by the Reference 30 study. In a trial fleet conversion of police
vehicles using Device 52, spark plug life was found to be 30,000 miles or more
with LPG, compared to an average of 8,000 miles with gasoline, and oil change
mileage was upped to 10,000 miles from 3,000 miles (Reference 29). Table 6-6
summarizes the maintenance costs for the gasoline- and LPG-fueled vehicles used
in this conversion program.
Table 6-6. DEVICE 52 LPG CONVERSION VEHICLE MAINTENANCE
COST COMPARISON (REFERENCE 29)
VEHICLE
CONFIGURATION 1)
LPG-Fueled
Gas -Fueled
MILEAGE
ACCUMULATED
46,681
42,980
SERVICE
AND REPAIR
COSTS
$63.80
.$221.81
MAINTENANCE
COST/MILE
0.136(?/mi
0.516c/mi
(1) Two 1969 Ford Custom 500's with 428-CID engines and two
1969 Dodge Coronets with 383-CID engines were compared,
with one of each type converted to LPG using Device 52
Type D carburetors (shown in Figure 6-1). Each car had
a standard police package and automatic transmission,
and were run in the same 24-hour patrol service.
These maintainability benefits are corroborated by reports from other LPG fleet
operators documented in Reference 46.
6.1.1.6 Driveability and Safety
6.1.1.6.1 Driveability. Driveability tests were performed in both of the HEW/
NAPCA tests of Device 52 (References 38 and 39 )0 These two test programs enable
a comparison between the driveability of an LPG-converted vehicle that is not
tuned for low emissions and converted vehicles that are tuned for low emissions.
In the Reference 38 program, the 1968 Buick Skylark tested was representative of
the emission levels resulting from a single-fuel conversion from gasoline to LPG.
qualitative tests, the test personnel generally agreed that the driveability of
the vehicle was good. In cold-start driveaway tests, the car was considered to
be superior to a conventional vehicle. Power loss was insignificant and in cold
starts at ambient temperatures below 20F, the car started as well as gasoline-
fueled vehicles, even though it was not known whether the engine was in the opti-
mum state of tune for LPG.
In
6-17
-------
The Falcons and Rebels tested in the Reference 39 program had been tuned for low
emissions by having the distributor vacuum advance disconnected and the timing set
at top dead center. The driveability of these vehicles was substantially degraded,
Heavy tip-in and stretchiness problems occurred during acceleration. Some of the
vehicles were so sluggish that entrance to expressways could be hazardous. With
the spark advanced to 3 degrees BTDC on one Rebel for comparison, substantial
improvement in acceleration resulted. Table 6-7 shows the averages obtained in
acceleration tests of these vehicles.
Table 6-7. DEVICE 52 LPG CONVERSION ACCELERATION TEST RESULTS WITH SPARK
RETARD AND VACUUM ADVANCE DISCONNECTED (REFERENCE 39)
VEHICLE
Falcon (1)
Rebel (1)
Rebel with 3-degree
BTDC advance
Gasoline -Fueled
Vehicle (2)
ACCELERATION (SEC)
20-50 MPH
11.4
11.4
8.9
9.6
0-60 MPH
20.1
20.0
17.0
17.9
50-80 MPH
31.6
31.0
22.9
(3)
(1) Four vehicles tested with LPG conversion and engine tuning
as noted in Table 6-3.
(2) This was a 1969 gasoline-fueled Ambassador with 232-CID
engine and odometer reading 31,000 miles.
(3) Ignition problem caused car to malfunction.
The 1969 gasoline-fueled Ambassador was tested to obtain acceleration data for
comparison. This car was heavier than the Rebel, but it had basically the same
232-CID engine. Even though it had faulty ignition, it performed better than the
Rebels. As the results for the Rebel with 3-degree BTDC advance indicate, the
driveability problem appears to be attributable to the retarded timing and lack of
spark advance rather than to the LPG. This indication was corroborated by drive-
ability tests of a Falcon with the timing advanced to 6 degrees. Advancing the
timing helped the overall driveability of the vehicle, but increased HC by 22
percent, CO by 13 percent, and NOx by 35 percent.
One of each type vehicle used in the Reference 39 program was driven under ordinary
driving conditions as part of the test organization's vehicle fleet. This was done
to check emission reduction, fuel consumption, and comparative performance with
mileage accumulation. During 700 miles of operation the Rebel showed no substan-
tial change in emission levels. The Falcon was driven with 6-degree BTDC timing.
Fuel consumption results are shown in Table 6-8, compared to gasoline-fueled
vehicles of the same type.
6-18
-------
Table 6-8. DEVICE 52 LPG CONVERSION FUEL CONSUMPTION COMPARISON
VEHICLE
Rebel (1)
Falcon (2)
MILES PER
GALLON .
LPG
8.8
11.2
GAS(3)
20-21
19-20
PERCENT
DECREASE
56
41
(1) With TDC timing and distributor vacuum
advance disconnected.
(2) With 6-degree BTDC timing and distributor
vacuum advance disconnected.
(3) Manufacturer's advertized mileage per
gallon for the same model-year vehicle
operating on gasoline (Reference 43) 0
The amount of fuel mileage decrease shown in Table 6-8 is excessive compared
with data from other studies (Reference 29). Since propane has about 27 percent
less Btu per gallon than gasoline (83,200 versus 114,500), a propane-fueled
vehicle could be expected to consume more propane on a volume basis than it
would on gasoline, assuming that the same number of Btu is required. Comparisons of
four 1969 light-duty vehicles in the Reference 29 program under the same 24-
hour continuous patrol service over more than 42,000 miles resulted in an av-
erage fuel consumption of 7.9 miles per gallon for propane and 9.3 miles per
gallon for gasoline. This 15 percent loss of gas mileage was offset by an over-
all 32 percent savings on the fuel costs for propane.
The unusally high LPG fuel consumption reflected in Table 6-8 may be attribut-
able to the retarded spark and vacuum advance disconnect, which degradated
vehicle performance. Propane fuel consumption increase over gasoline of approx-
mately 30 percent was obtained when using retarded spark in the Reference 26
program. Other studies also have indicated that the fuel consumption of a propane
fueled engine increases as air-fuel ratio is increased concurrent with retard-
ing of the spark beyond the best fuel and power settings (Reference 30).
6.1.1.6.2 Safety. Device 52, being typical of LPG systems, is subject to the same
same concern as to the safety of LPG as any similar device would be. This con-
cern is placed mainly on the possibility of the LPG tank exploding, either from
excess pressure buildup or accidental rupture from external cause, and on the
threat of gas leakage with the consequent possibility of fire. Propane is odorless
as manufactured and is required by safety regulations to be odorized, so as to
be traceable in the event of leakage (Reference 47). Since it weighs 50 percent
more than air, it settles to low areas or depressions.
6-19
-------
The Interstate Commerce Commission has noted that LPG equipment is practically
never involved in a fire accident because of failure or rupture of the fuel
system (Reference 46). The American Society of Mechanical Engineers' safety code
for LPG tanks is 250 psi working pressure and a 5 to 1 burst pressure (Refer-
ence 48). Thus a tank would be capable of sustaining 1,250 psi without rupturing.
The average LPG tank for a light-duty vehicle, when 80 percent full, operates at
approximately 130 psi when the ambient temperature is 80F and at 240 psi when the
temperature is 120F (Reference 51).
Although there is no loss of LPG vapor in normal operation, the National Fire Pre-
vention Association requires that tanks located in vehicle trunks be equipped with
relief valves and that the passenger area be sealed off from the trunk (Refer-
ence 49). Under proposed California regulations, remote filling of the tank from
outside the vehicle, with the trunk lid closed, will be required (Reference 50),
eliminating the requirement for a sealed trunk.
The usual precautions are necessary when filling the tank, such as adequate vent-
ilation, engine shut off, and no smoking. The vehicle driver should be know-
ledgeable in the characteristics of propane, refueling steps, and steps to be
followed in case of leak or other emergency situations.
6.1.1.7 Installation Description
Conversion of light-duty vehicles for use of LPG is performed as standard prac-
tice by a number of companies. Within California such conversions are given
the incentive of a 6<: per gallon road tax refund, if the conversion incorporates
a carburetor that is certified to meet the emission standards for the model
year vehicle being converted. The plan for future standardization and control of
such installations is to place them under the California Highway Patrol, which
also is chartered to regulate installation and inspection of vehicle emission
control devices (Reference 25).
The installation procedure described in this paragraph is based on the type of in-
stallation required for use of LPG to meet emission standards (Reference 34).
The installation utilizes Device 52 single-fuel LPG components and complies
with LPG conversion emission requirements as specified by California (Reference 50),
and the safety requirements of the National Fire Prevention Association (Reference
49).
The basic single-fuel LPG installation procedure for a typical passenger veh-
icle in the 250-CID and over engine class is itemized in Table 6-9. The principal
components identified in this procedure are shown in Figure 6-2. The installa-
tion procedure divides broadly into four phases:
a. Pre-conversion engine inspection during which the
cylinder pressures are checked to verify that rings
and valves are in satisfactory condition.
b. Engine installation of converter and carburetor.
c. Tank installation and hookup.
d. Emission standards compliance test.
6-20
-------
Table 6-9. DEVICE 52 LPG CONVERSION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN. )
1. Remove spark plugs and compression
check each cylinder.
Note: Vehicle is rejected for conversion
if compression of any one cylinder is
less than 20 percent from manufactur-
er's specified compression. To
qualify for conversion the engine
would have to be reworked as neces-
sary to pass the compression check.
If engine is reworked, and is a pre-
1970 model, valve seats should be
replaced with hardened seats. If
engine has exhaust valve rotators on
top of valve spring, deactivate*
2. Install new spark plugs, points, and
condenser. Check spark plug leads
for dielectric breakdown and replace
as required.
3. Install mounting bracket for convertei
and fuel filter plus vacuum fuel lock
unit on fender well nearest engine
cooling lines.
4. Install converter and fuel filter
plus vacuum fuel lock unit on
mounting bracket (tighten all
component screws first).
5. Install T-fittings in the heater
inlet and outlet lines as close to
the engine as possible. If unused
engine and water pump openings are
available, use them.
6. Connect heater water inlet T to the
converter's lowest water connection,
and connect heater water return T to
other converter water connection,
using standard heater water hose.
Pressure gage
20
Hand tools
30
a. Electric drill
b. Hand tools
Hand tools
Hose cutter
Hose cutter and hand tools
6-21
-------
Table 6-9. DEVICE 52 LPG CONVERSION INSTALLATION PROCEDURE (CONT)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
7. Connect vacuum fuel lock to intake
manifold vacuum fitting. Drill and
tap hole if necessary.
8. Remove existing gasoline carburetor,
fuel pump, fuel tank and intercon-
necting fuel lines. Install cover
plate over fuel pump opening.
9. Install Type C carburetor adapter
on intake manifold, mount carburetor,
and hook up throttle linkage.
10. Disconnect heat riser and plug auto-
matic choke outlet in exhaust
manifold.
11. Install 160F thermostat in engine
cooling system.
12. Remove rear seat and install LPG 35-
gallon tandem tank set.
13. Install LPG fuel gage on instrument
panel and interconnect electrical
wiring to tank
14. Install fiberglass sheeting to seal
opening between passenger compartment
and trunk. If vehicle is equipped
with rear window defrosters or radio
speakers, seal these off with fiber-
glass.
15. Install stainless-steel wire braid
liquid hose between LPG tank gas
valve outlet and converter in engine
compartment.
16. Install vent line between tank relief
valve and trunk deck floor.
Hand tools
Hand tools
Hand tools
Hand tools
Electric drill and hand tools
Hand tools
Fiberglass, resin, and brush
Hand tools
Electric drill and hand tools
15
30
10
60
15
45
15
6-22
-------
Table 6-9. DEVICE 52 LPG CONVERSION INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
17. Install remote fill line.
18. Install vapor hose between converter
low pressure outlet and Type C LPG
carburetor.
19. Fill LPG tank with commercial pro-
pane to 80 percent gage level and
inspect all fittings and lines for
leakage.
20. Prime carburetor at converter and
start engine. Inspect carburetor,
converter and fuel lines for leaks.
21. Set engine timing and idle rpm to
manufacturer's specifications.
22. Set air-fuel ratio at idle and wide
open throttle for lowest emissions.
23. Test emissions with vehicle on
dynamometer, using one 7-mode cycle
in accordance with Reference 45.
Hand tools and drill
Hand tools
None required
None required
a. Hand tools
b. Engine analyzer
Engine analyzer
Chassis dynamometer
equipped with power ab-
sorption unit and fly-
wheels
Engine cooling fan
Exhaust sampling and ana-
lytical system.
Total
30
3
30
(6 hr,
12 hrs
man)
6-23
-------
Figure 6-9 shows a typical Device 52 single-fuel engine conversion and LPG tank
installation. This installation would require an automotive mechanic specially
trained in LPG carburetors and a mechanic assistant. Average installation time
is 12 hours.
6.1.1.8 Initial and Recurring Costs
Estimates as to the cost of installing a Device 52 LPG system in place of an
existing gasoline system range from $300 to over $600 (References 26, 30, and
34). The principal cost factors are the~~si£e of the fuel tank and whether
the installation is designed to meet safety and emission standards. Other cost
variables are the options, such as instrument panel fuel gage and auxiliary
fuel outlet valve, that the vehicle owner may desire. The cost of the compo-
nents and tank making up the most basic LPG conversion kit of minimally reason-
able driving range (150 miles) would be more than $300, based on component
prices provided by the Device 52 manufacturer and tank prices shown in Refer-
ence 46,, Labor to install such a kit would cost approximately $150, not includ-
ing tuneup or any of the special vehicle modifications required for safety.
The initial and recurring costs for a complete light-duty vehicle conversion
to LPG are shown in Table 6-10. The initial cost of $607.95 is based on the
type of installation that would be required to meet the proposed California
regulations for gaseous fuel conversions (refer to Table 6-9). That installa-
tion is specifically designed to meet the safety requirements of the National
Fire Prevention Association and the emission standards for the vehicle model
year being converted (References 49, 50, and 51).
The initial cost for such an installation assumes that the engine of the veh-
icle being converted is in good condition. As with any retrofit method for
controlling vehicle emissions, the effectiveness of the retrofit depends on
whether the engine's condition is reasonably close to the manufacturer's
specification. If the engine required rings and a valve job to qualify for
conversion, the initial cost might increase by 50 percent. A minimum require-
ment for most vehicles would be a tuneup to manufacturer's specifications.
This would eliminate the engine as the cause of operating problems immediately
after the conversion. For the initial cost estimate shown in Table 6-9,
the vehicle engine is assumed to be in the 300- to 375-CID class and the car-
buretor is assumed to be a Device 52, Type C (Figure 6-1).
Although the initial costs are high, the savings indicated by the reduced
fuel and maintenance costs could possibly pay for the initial costs almost
100 percent over 50,000 miles of operation. As shown in the recurring cost
estimate of Table 6-10, the savings in operational and maintenance costs over
a 50,000 mile period would be $605.26, assuming that a vehicle is maintained
to manufacturer's specifications. This would reduce the net initial cost to
$5.82.
6-24
-------
(a) Engine Compartment with Carburetor (Left)
and Converter (Right)
(b) Fuel Tank Installed in Vehicle Trunk
Figure 6-9. DEVICE 52 SINGLE-FUEL LPG INSTALLATION'
(REFERENCE 52)
6-25
-------
Table 6-10. DEVICE 52 LPG CONVERSION INITIAL AND RECURRING COSTS
FOR TYPICAL CONVERSION TO MEET EMISSION STANDARDS
ITEM
Initial Costs:
Material
1. LPG Fuel tank
2. Fuel filter and
lock
3. Converter and
regulator
4. Carburetor and
adapter
5. Dash panel fuel
gage
6. Trunk vent and
remote fill line
7. Fiberglass
8. Hoses, fittings,
and brackets
9 . Points and spark
plugs
10. Thermostat
Labor
Total labor to
install Items
1-10 above and
to perform tune-
up and emissions
test (reference
Table 6-9)
DESCRIPTION
35-gallon tandem set
Type C
(Figure 6-1)
To seal trunk
To connect tank,
converter, and
carburetor
160F
Two mechanics ,
LABOR HOURS OR
ITEM QUANTITY
1 set
1 each
. 1 each
1 each
1 each
1 each
a. 1 set points with
condensor
b. 8 plugs
12 man-hrs at $12.50
per hour
COST
(DOLLARS)
$165.00
24.95
75.00
65.00
14.00
40.00
20oOO
40.00-
3.50
8.00
2.50
150.00
Total Initial Costs 607.95
6-26
-------
Table 6-10. DEVICE 52 LPG CONVERSION INITIAL AND RECURRING COSTS
FOR TYPICAL CONVERSION TO MEET EMISSION STANDARDS (CONT)
ITEM
50,000-Mile
Recurring Costs: (Est
Material/Labor Savings
1 . Fuel Savings per
Vehicle
Gasoline
LPG
2o Oil Change Saving
Vehicle
Gasoline
LPG
3 o Tuneup Savings P«
Vehicle
Gasoline
LPG
Labor Expenditure
!„ Fuel Filter
DESCRIPTION
Lmated savings by conv<
(1)
50,000 miles
MPG Gal/50,000 Mi
12.5 4,000 X
10.6 4,717 X
Fue
s Per 50,000 Miles
Oil/Filter
MMBM $/ Change (2)
3,000 10.25 X
10,000 10.25 X
Oil Change
r 50,000 Miles
MMBM $/ Tuneup
8,000 30.00 X'
20,000 30.00 X
Clean .once at
25,000 miles
]
Total In:
Less Net
LABOR HOURS OR
ITEM QUANTITY
rting to LPG)
$/Gal. Fuel Cost
0.35 = 1,400.00
0.22 = 1,037.74
L Savings $362.26
No Changes Cost
16 = 164.00
4 = 41.00
Savings $123.00
No. Tuneups Cost
'. 6 180.00
2 = 60.00
$120.00
Estimated Savings
0.25 hr & $12.50
per hr
ESTIMATED NET SAVINGS
Ltial Costs 607.95
Savings 6-2.13
TOTAL COSTS
COST
(DOLLARS)
362.26
123.00
120.00
605.26
3.13
602.13
5.82
(1) Based on the comparison of LPG- and gasoline-fueled light-duty vehicle
maintenance requirements reported by the Chandler, Arizona, Police
Department (Reference 29).
(2) Eight quarts of oil at 85
-------
The Table 6-10 estimate of recurring cost savings is based on operations and
maintenance data reported to the Device 52 manufacturer by the Chandler Arizona
Police Department in 1970 (Reference 29). At that time, after approximately
50,000 miles of operation, the LPG-fueled police vehicles had been operating
at a 44 percent less dollar-per-mile cost than the gasoline-fueled vehicles
($0.0295 per mile for the gasoline vehicles compared to $0,0165 per mile for the
LPG vehicles). The Chandler Police Department reportedly is operating and
maintaining a 12-car LPG patrol fleet with the same cost savings (Reference 33).
6.1.1.9 Feasibility Summary
As reported by the National LPG Association, Chicago, Illinois, LPG has been
used as a fuel for the internal combustion engine for over 50 years (Reference
53). The Device 52 manufacturer has produced LPG system components for about
15 years, and since 1969 has met California exhaust emission standards for
light-duty motor vehicles. Thus the technical feasibility of Device 52 as a means
of achieving used vehicle exhaust emission control by retrofitting LPG systems appears
adequate. Since it is possible to eliminate the original equipment fuel pump,
fuel tank, and emission control accessories such as air pumps and air injec-
tion manifolds when converting to a single-fuel LPG system, it is apparent that
the basic technical feasibility of Device 52 is considerably enhanced by the
simplicity of operation that it could provide. Also there are the indicated
benefits of longer engine life,reduced engine maintenance and lower operating
costs to be considered,, In addition, there is the fact that an LPG system
provides control over evaporative emissions, since it is a sealed system,
except for the ,LPG tank relief valve which normally should never operate.
Thus the 20 percent of total vehicle hydrocarbon attributable to fuel evapora-
tion is eliminated with an LPG single-fuel system. Furthermore, the emissions
that come from the exhaust when using LPG are not as reactive in their capa-
bility to produce photochemical smog; hence LPG is inherently less polluting
than gasoline.
The obvious technical feasibility of the Device 52 approach to vehicle emissions
control does not dismiss equally important economic factors. One is the high
initial cost of an LPG conversion and another is whether there would be suffi-
cent LPG fuel available for a major retrofit effort.
The high initial cost of converting a vehicle to LPG, with the objective of
reducing emissions, would be a prohibitive expense for the average vehicle
owner. The indicated initial cost of a conversion is about one-sixth the
price of the average new car, and is about equal to the Blue Book value of
pre-1967 vehicles. Even though the recurring cost savings that LPG appears to
provide over gasoline could pay back the initial cost^ this would be possible
only if the converted vehicle is good for another 50,000 miles of operation.
Should an older vehicle require major overhaul to qualify for conversion, the
initial cost would be that much higher and the payback period would extend
correspondingly past 50,000 miles.
6-28
-------
To be considered for conversion under any regulated retrofit program it would
appear that a vehicle should have been operated less than 50,000 miles. Assum-
ing that such a vehicle had been maintained satisfactorily, it could possibly
be converted without major overhaul and operated for another 50,000 miles or,
because of the reported LPG benefits, longer. Considering the odometer mileages
recorded in the EPA Short Test Cycle Effectiveness Study Program (Reference 17),
pre-1968 cars would be ineligible for LPG conversion on this basis. With this
model-year as the cutoff point for conversion eligibility, approximately
two-thirds of the used car population would be excluded from control by LPG
(Reference 54).
Since exhaust emission controls were incorporated on vehicles nationally begin-
ning with the 1968 model year, the use of LPG as a retrofit control becomes a
matter of whether LPG is significantly more effective than the factory installed
controls. From the emission test data of Tables 6-2, 6-3, and 6-4, it would
appear that some retarding of engine timing, along with distributor vacuum
advance disconnect, would have to be used in combination with LPG if the exhaust
emissions of the controlled baseline vehicle are to be significantly reduced.
The specific compromise to be made between emission control and vehicle perfor-
mance would have to be established for each model year vehicle.
Assuming that all post-1967 vehicles were to be converted to LPG, the availa-
bility of fuel would be a factor to consider. Based on LPG carburetor sales
over the past 10 years, automobile engines represent about 7 percent of the
internal combustion engines equipped to run an LPG (Reference 55). Since engine
fuel use of LPG is 7.6 percent of total LPG sales (Reference 30) automobile
engines represent about 0.5 percent of the total propane usage. In automobiles,
this represents the total of 81,140 which have been converted since 1960 to run
on LPG. With propane production predicted to increase 2.5 percent a year through
1980 (Reference 56), approximately 405,700 automobiles could be converted to
propane in 1972, if the total production increase of propane for that year were
used as automobile fuel. If the 2.5 percent increase in propane were to be con-
tinued to be used to supply automobile fuel, an average of approximately 450,000
more converted vehicles could be supplied.each year through 1980. Cumulatively,
by 1980 about 4 percent of the total light-duty vehicle population could be
operating on propane. As other studies have indicated, propane 11-650 would have
to become a principal rather than a byproduct of the oil and natural gas
industries if all motor vehicles were to be converted (References 30 and 47).
As noted in Reference 50, the supply of LPG may increase as the requirements
for leaded gasoline decrease and also as the use of LPG as a chemical feedstock
fluctuates with the market price (the higher the price, the more LPG is diverted
to the commercial market). With no lead in gasoline the production of propane
could be increased approximately 60 percent by 1980; however, this would require
$5-10 billion of capital outlay by the oil and natural gas industry, and would
increase refinery investment by 40 percent (Reference 30). This would be equi-
valent to making propane the primary product of the industry, rather than a
byproduct. If this were done, the refinery price of propane would almost double
(Reference 30), and its present economic benefits would be lost. Based on these
considerations, it would appear that a major shift to the use of LPG as a motor
vehicle fuel would require an equivalent move in the oil and natural gas indus-
try to increase LPG supply.
6-29
-------
Because of its high initial cost and the relatively inadequate LPG fuel supply,
it appears that the Device 52 LPG conversion would be more applicable to use
on fleet vehicles rather than privately owned cars. Fleet vehicles are generally
the ones for which the maximum recurring cost savings could be obtained by
conversion to LPG, since they are usually later model vehicles that are maintain-
ed and serviced on a controlled schedule. Fleets could be selected for conver-
sion on the basis of climatological conditions affecting air quality, geographi-
cal density of vehicle population, number of vehicles and mileage rate of
vehicle usage. This would enable the use of LPG either to stay within the
predicted 2.5 percent supply growth, or to increase in accordance with planned
production growth. Should LPG fuel systems and engines be incorporated in
new model vehicles, requiring propane to J?e produced as a primary product,
retrofit applications could then be expanded beyond fleet vehicles.
6-30
-------
6.1.2 Device 466: LPG-Gasoline Dual-Fuel Conversion
This device is a production LPG conversion system that is typically used for dual-
fuel applications (Reference 58). The carburetor of the system has been accepted
by the California Air Resources Board as meeting California emission standards
(Reference 65). System information was obtained from HEW/NAPCA emission test re-
ports and by telephone contact with the manufacturer (References 38, 57, and 58).
6.1.2.1 Physical Description
Although a detailed system description was not obtainable within the time frame
of the retrofit study program, coordination with the manufacturer indicated that
the system configuration is similar to Device 52 (paragraph 6.1.1). The manur
facturer produces the system carburetor, converter, and the filter/fuel-lock unit.
These components are combined with an LPG fuel tank, fuel lines, and vent valves
to form a complete system.
Figure 6-3 is representative of a dual-fuel installation. The Device 466 car-
buretor mounts on top of the existing gasoline carburetor, as shown for the Device
52 dual-fuel configuration. As with Device 52, Device 466 also can be used in a
single-fuel configuration. In this configuration it mounts directly to the intake
manifold by means of an adapter.
6.1.2.2 Functional Description
The Device 466 carburetor is controlled under the same patent as Device 52, and
operates on the same air valve principle as described in paragraph 6.1.1.2. All
other system components function as described in that paragraph.
6.1.2.3 Performance Characteristics
The results of emission tests performed by HEW/NAPCA with Device 466 installed
on a 1969 Ford Galaxie are shown in Table 6-11. This vehicle was equipped to run
on gasoline, as well as LPG; thus it was possible to obtain comparative emission
data, using gasoline as the engine fuel, from the same vehicle. The high CO re-
duction obtained when using LPG was 85% and the HC reduction was 37% NOx increase. Ex-
haust hydrocarbon composition by subtractive column analysis showed that the olefin con-
tent of the LPG fuel was approximately 30 percent less than that of the gasoline
used, whereas the aromatic content was about 50 percent less. The paraffins, how-
ever, were 54 percent greater in the LPG fuel. These results accord with the fact
that LPG contains less of the highly reactive olefin and aromatic hydrocarbons.
The results obtained for the subtractive column analysis of exhaust hydrocarbon
composition are presented in Table 6-12.
Table 6-13 presents the results of additional exhaust emission tests performed on
Device 466. In these tests seven vehicles were equipped with LPG systems incor-
porating Device 466 carburetion. The test report (Reference 57) indicates that a
Device 466 representative was present to make fuel mixture.adjustments. According
to the test report, these data indicate the chief advantages of LPG-fueled cars:
good control of carbon monoxide, average HC reduction, and average NOx reduction.
6-31
-------
Table 6-11. DEVICE 466 LPG GASOLINE DUAL-FUEL CONVERSION
EMISSION TEST RESULTS (REFERENCE 38) (1)
VEHICLE
CONFIGURATIONS (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
7.36
2.70
37
CO
37.77
5.59
85
NO
X
5.2
8.6
-65
(1) Results of one test using CVS 9-cycle, 7-mode test
procedure (Reference 16) .
(2) 1969 Ford Galaxie with 351-CID engine and automatic
transmission.
Table 6-12. DEVICE 466 EXHAUST HYDROCARBON COMPOSITION BY
SUBTRACTIVE COLUMN ANALYSIS (REFERENCE 38)
VEHICLE
CONFIGURATION
LPG Ford (1)
Gasoline Ford
PERCENT OF TOTAL HYDROCARBONS
PARAFINS &
BENZENES
61.7
40.0
OLEFINS
26.1
36.4
AROMATICS
12.2
23.6
(1) Averages of data recorded during exhaust emission
tests of Table 6-11.
6.1.2.4 Driveability and Safety
Qualitative driveability tests were performed in both the Reference 38 and 57 test
programs of Device 466. In the first test program, using a 1969 Ford Galaxie, the
test staff generally agreed that driveability was good. Power loss was insignifi-
cant. This driveability test was performed without knowing whether the vehicle
was tuned for the best performance with LPG.
In the second test program, the vehicles apparently had been tuned for best
emission performance. The test report notes that driveability "...was typical of
lean operation, with slight hesitation on tip-in, stretchiness on accelerations,
and surging during cruise."
6-32
-------
Table 6-13. DEVICE 466 EMISSION TEST RESULTS
(REFERENCE 57) (1)
VEHICLE
CONFIGURATION (5)
Ford (2)
Plymouth /Dodge (3)
Rambler Rebel (4)
Average
Percent Reduction
POLLUTANT (CM/ME)
HC
WITH
DEVICE
2.41
2.36
2.98
2.58
WITHOUT
DEVICE
3.12
3.39
3.04
3.18
19
CO
WITH
DEVICE
4.23
7.20
15.36
8.93
WITHOUT
DEVICE
28.46
30.45
31.47
30.13
70
NOx
WITH
DEVICE
1.78
2.88
2.62
2.43
WITHOUT
DEVICE
3.58
3.63
3.08
3.43
29
(1) Results are from 6 tests using 1972 Federal Test Procedure
(Reference 3) .
(2) One 1968 Ford Ranch Wagon station wagon with 302-CID engine.
(3) Three 1969 Dodge Coronets with 318-CID engine..
(4) Two 1969 Rebel station wagons with 343-CID engines.
(5) All vehicles tested were 4-door and had automatic transmissions.
Emission data for gasoline-fueled vehicles of equivalent model
year and engine size were used from the existing NAPCA file for
comparison.
The device manufacturer stated that driveability of a vehicle equipped with the
system is equivalent to the driveability of any vehicle that incorporates exhaust
controls capable of meeting emission standards (Reference 58).
The device should have no safety problems if installation procedures similar to
those described in paragraph 6.1.1.4 are followed. The manufacturer stated that
the safety requirements of the National Fire Prevention Association (Reference 49)
are met in all system installations.
6.1.2.5 Reliability
The manufacturer stated that the device has a reliability of several vehicle life
times. It is standard practice for vehicle owners to transfer system components
from one vehicle to the next as older model vehicles are replaced by newer models.
6.1.2.6 Maintainability
The manufacturer stated that periodic maintenance would be required only on the fuel
filter. If HD-5 propane is used, the filter should not have to be cleaned more than
once every 25,000 miles.
6.1.2.7 Installation Description
The installation procedure described in paragraph 6.1.1.7 for Device 52 is repre-
sentative of the Device 466 installation.
6-33
-------
6.1.2.8 Initial and Recurring Costs
The manufacturer reported that component costs for a typical installation are basic-
ally the same as competing systems. It is assumed therefore that a vehicle conver-
sion using Device 466 to meet California emission standards and installation re-
quirements (References 45 and 50) would have approximately the same initial and
recurring costs as summarized in Table 6-10.
6.1.2.9 Feasibility Summary
Device 466 indicates an overall emission reduction of all three pollutants.
If the emission data were corrected for exhaust dilution and reactivity factors
as provided for in the California gaseous fuel test procedure (Reference 50),
the relative effectiveness would be higher. The device is readily obtainable in
a production model, and is in use on privately owned and fleet operated vehicles.
As for Device 52, the device appears to be a feasible candidate for retrofit to
late-model vehicles, particularly fleet operated vehicles. In this way, the high
initial costs of the device would be repaid through the savings in operational
and maintenance expenses over the vehicle's service life.
6-34
-------
6.1.3 Device 459: LPG Conversion with Deceleration Unit (1)
This device incorporates one of the three LPG carburetors (refer also to
Devices 52 and 466) which have been accepted by the California Air Resources
Board as meeting California emission standards. The device is in production
and the carburetors are obtainable in two accepted models for control of exhaust
emissions from light-duty vehicle engines of 300 and over cubic inch displace-
ments .
Evaluation of the device was based on information obtained from the manufacturer
and from a HEW/NAPCA exhaust emission test report (References 59, 60 and 66).
6.1.3.1 Physical Description
A typical Device 459 system is shown in Figure 6-10. The carburetor is a
single-fuel LPG mixer that mounts on the engine intake manifold in place of
the conventional gasoline carburetor. As shown in Figure 6-10, the carbure-
tor operates as part of an overall LPG fuel system much like Device 52 (Figure
6-2). The system components produced by the manufacturer include the conver-
ter and the filter/fuel-lock unit. The deceleration device tested by HEW/
NAPCA with Device 459 was an auxiliary component not provided by the Device
459 developer (Reference 59).
6.1.3.2 Functional Description
As described in Reference 66, the liquid gas, stored under pressure in an ap-
proved tank, flows through high pressure hoses and fittings, a fuel filter
and an electric solenoid safety valve, to a vaporizer-regulator heat converter,
where the liquid is converted to a vapor in two stages of regulation. From
the converter, the vaporized LPG is metered through the carburetor to the
engine in accordance with the engine's requirements. When the high pressure
liquid is changed to a low pressure vapor the refrigerating action that takes
place within the regulator is counteracted by circulating hot water from the
engine coolant system through a cavity in the heat exchanger.
As in any LPG system, the carburetor is the key component with respect to
emission control. The Device 459 carburetor, shown in Figure 6-11, is of the
metering valve type (Reference 47). The carburetor feeds the gaseous fuel
into the incoming airflow through a spray bar or ring. The spray bar or ring
is located transversely across the carburetor, approximately midway between
the intake manifold end of the carburetor and the airflow-control butterfly
valve. The amount of fuel flowing through the bar or ring is controlled by
a valve located in the fuel inlet line. This fuel-flow valve and the airflow-
control butterfly valve within the carburetor are interconnected by means of
a drag link. By varying the adjustment on each valve, idle rpm and mid-
through-high-range air-fuel ratio are adjusted. Idle air-fuel ratio is ad-
justable separately, by means of a variable orifice fuel circuit that bypasses
the main fuel flow valve.
(1) Device 459 represents an LPG conversion of a vehicle already equipped with a
deceleration unit. The developer shown for Device 459 in Volume V, Appendix
V-l, is the manufacturer of the LPG system. The details of the deceleration
unit are not known.
6-35
-------
CONVCIIEI MUSI IE MOUNTED KLOW THC LiVtL Of l*HI «AOIAJO« TANK
Figure 6-10. DEVICE 459 LPG CONVERSION SYSTEM ILLUSTRATION (REFERENCE 66)
SPRAY BAR
AIR INLET
CALIBRATION CUT
LPG METERING VALVE
FROM CONVERTER
DRAG LINK ASSY.
AIR THROTTLE
Figure 6-11. DEVICE 459 SINGLE-FUEL AIR VALVE CARBURETOR (REFERENCE 66)
6-36
-------
6.1.3.3 Performance Characteristics
The results of NAPCA emission tests on Device 459 are summarized in Table
6-14.
As noted in the NAPCA report, the vehicle tested with Device 459 installed
met the 1972 Federal exhaust emission standards for light-duty vehicles
(2.9 gm/mi HC, 37.0 gm/mi CO, and 3.0 gm/mi NO ). The deceleration device
was credited with decreasing HC by 20 percent and CO by 6 percent more than
the percentage reduction achieved with Device 459 alone.
Table 6-14. DEVICE 459 LPG CONVERSION WITH DECELERATION UNIT EMISSION
TEST RESULTS (REFERENCE 60) (1)
VEHICLE
CONFIGURATION
Test Vehicle (2)
POLLUTANT (GM/MI)
HC
WITH
DECEL
1.04
WITHOUT
DECEL
1.29
CO
WITH
DECEL
3.77
WITHOUT
DECEL
3.99
NOx
WITH
DECEL
1.95
WITHOUT
DECEL
1.94
(1) Results based on 1 test using 1972 Federal Test Procedure (Reference 3) .
No baseline test performed.
(2) 1969 Ford LTD with 429-CID engine and automatic transmission.
6.1.3.4 Reliability
The manufacturer stated that the device's reliability is such that the same compo-
nents can be used from one model year vehicle to the next. A Device 459 system
has been driven 197,000 miles on a 1967 Pontiac with no change in emission reduc-
tion effectiveness. Tested in January 1971, under the 1972 Federal Test Procedure,
this vehicle had the following grams per mile emission levels:
HC
1.0
CO
4.8
NOx
1.2
6.1.3.5 Maintainability
During the 197,000 miles accumulated on the 1967 Pontiac, the only maintenance
performed was periodic tuneup of the engine. It is assumed that an LPG system
incorporating Device 459 would require no maintenance other than that described
for the typical LPG conversion in paragraph 6.1.1.6. Under this maintenance
requirement, the fuel filter would be cleaned at 25,000 miles.
6-37
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6.1.3.6 Driveability and Safety
The manufacturer stated that driveability of a vehicle is not noticeably de-
gradated when operated with the device. Safety characteristics are equivalent
to those of any LPG system (refer to paragraph 6.1.1.4).
6.1.3.7 Installation Description
With installation requirements for the deceleration unit added, the installa-
tion described in paragraph 6.1.1.7 is representative of that required for
Device 459. The specific installation details of the deceleration unit are
not known. The manufacturer reports in Reference 66 that in converting en-
gines from gasoline to LPG, cooling the intake manifold can reduce NOx.
Cooling of the intake manifold is accomplished by closing off the manifold
heat control valve and wherever possible by placing an insulated plate be-
tween the exhaust and intake manifolds. On some manifolds, heating is pro-
vided by cast fins which conduct the heat from the exhaust manifold to the
intake manifold. By removing or cutting through these fins, cold manifolding
is accomplished.
As in the typical installation shown in Figure 6-10, the converter usually
is mounted in an upright position below the level of the water in the radia-
tor so as to promote circulation of water. To assure complete circulation at
all times, water is taken either from a boss on the cylinder head or the
heater hose connection, heat indicator unit, or bypass connection, circulated
through the vaporizer regulator water casting, and returned to the suction
side of engine coolant pump.
Preferably, the converter is mounted on a vibration-free member such as the
fire wall, fender panel or frame. The solenoid valve and filter may be
mounted on the regulator or on the fire wall or fender, with connecting hoses.
The various components should be mounted so they do not interfere with the
normal service items of the vehicle, such as the oil dip stick, battery cell
caps, generator and coil.
6.1.3.8 Initial and Recurring Costs
Based on the $70-80 list price reported for the carburetor by the manufacturer
the initial purchase price and installation cost of Device 459 would be approx-
mately the same as that shown in Table 6-10 for Device 52. Cost data for the
deceleration unit were not reported. It is assumed that the initial costs would
be repaid after 50,000 miles of use.
6.1.3.9 Feasibility Summary
By use of Device 459, a 1969 vehicle was controlled to 1972 emission standards.
This indicates that the device is an effective emission control method. Its
high initial cost however, as appears to be typical of LPG systems, removes
it from serious consideration for large scale retrofit to vehicles older than
1968, because the initial investment probably would not be recoverable.
6-38
-------
Since the device is marketed in production quantities, it is readily obtain-
able and appears to be a feasible candidate for retrofit to late-model fleet
vehicles. The auxiliary deceleration unit appears to enhance the HC emission
reduction capability without degradation of the CO and NOx reduction capability.
The extent to which this enhanced emission reduction capability may be canceled
by cost would have to be determined before including the deceleration unit as a
part of the Device 459 system.
6-39
-------
6.1.4 Device 461: LPG Conversion with Exhaust Reactor Pulse Air Injection
and Exhaust Gas Recirculation
This device shows the emission reduction attainable when the benefits of
LPG are combined with those of exhaust gas oxidation and recirculation.
6.1.4.1 Physical Description
The overall configuration details of this device are not known. It has been
tested for emission reduction effectiveness by EPA, installed on a 1971
Oldsmobile Delta 88 (Reference 61). Since the LPG conversion kit was made
by the manufacturer of Device 459, the LPG system configuration may be similar
that described in paragraph 6.1.3.1.
6.1.4.2 Functional Description
Based on its known performance characteristics, the LPG phase of this
emission reduction system, besides providing cleaner burning fuel, would enable
higher air-fuel ratios to be achieved with attendantly fewer HC and CO emis-
sion byproducts of combustion. The exhaust reactor phase of the system would
enable the HC and CO produced during combustion to undergo oxidation to
carbon dioxide and water. The exhaust gas recirculation phase would lower the
combustion temperature and thereby inhibit NOx formation.
6.1.4.3 Performance Characteristics
The emission test results obtained by EPA are summarized in Table 6-15. As the
EPA report notes, if exhaust dilution and reactivity factors for LPG were used
in the emission calculations in place of those for gasoline, the HC emission
would probably be less. Also the report notes that at the emission levels being
measured, the background hydrocarbon levels were quite high on some tests and
this may have influenced the levels recorded. The composition of the LPG fuel
was not known.
Table 6-15. DEVICE 461 EMISSION TEST RESULTS (REFERENCE 61) (1)
VEHICLE
CONFIGURATION
Test Vehicle (2)
Baseline Vehicle
% Reduction
POLLUTANT (GM/MI)
HC
0.87
(3)
CO
3.07
(3)
NOx
0.30
(3)
(1) Results from a single test using 1972 Federal Test Procedure
(Reference 3)
(2) 1971 Oldsmobile Delta 88
(3) No baseline test performed
6-40
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6.1.4.4 Reliability
Because of the lack of detailed design data, it was not possible to evaluate
the reliability of this device. It is assumed, however, that the reliability
would not be less than the reactor reliability. If the reactor is a thermal
type, reliability could be expected to exceed 50,000 miles, based on data
reported in paragraph 3.2.1.5. Equivalent reliability with a catalytic con-
verter should require clean engine operation'(refer to paragraph 3.1.1.5).
6.1.4.5 Maintainability
Assuming that the device incorporates a thermal reactor, the only planned
maintenance would be the cleaning of the LPG filter at 25,000 miles, as noted
for the typical LPG system described in paragraph 6.1.1.6.
6.1.4.6 Driveability and Safety
The high air-fuel ratios attainable with LPG combined with exhaust gas recir-
culation could produce driveability characteristics similar to excessively
lean fuel carburetion. These characteristics include combustion misfire and
stretchiness on accelerating. The EPA report states that after the first test
the carburetor was adjusted to improve driveability. Since CO increased on
subsequent tests, the adjustment may have been made to reduce a too lean air-
fuel mixture. After this adjustment, CO increased 50 percent over the ini-
tial reading, although the final average was still only 3.1 gm/mi.
No information on safety was reported.
6.1.4.7 Installation Procedure
Detailed installation procedures for this device are not known. An indication
of the installation requirements is provided, however, by the separate instal-
lation descriptions provided for reactors in paragraph 3.1.1.7, for LPG in
paragraph 6.1.1.7, and for exhaust gas recirculation in paragraph 4.1.2.7.
Total installation time is estimated to be approximately 18 hours, using
experienced automotive mechanics.
6.1.4.8 Initial and Recurring Costs
Although this device indicates very high emission reduction effectiveness,
its cost could be excessive for retrofit use. This excessive cost would be
attributable to the combination of LPG, which may cost over $600 (refer to
paragraph 6.1.1.8), with a reactor which may cost over $175 (refer to paragraph
3.1.1.8). When the cost of exhaust gas recirculation is added, the benefits
accruing from the reduced recurring costs associated with LPG systems would not
offset the initial cost enough to make this device acceptable for retrofit use.
The initial costs could be over $800.
6-41
-------
6.1.4.9 Feasibility Summary
Because of the unusually high initial cost indicated for Device 461, it would
appear to be economically infeasible for retrofit applications. These costs are
a result of the multiple approaches integrated by the device to achieve high
emission reduction effectiveness.
An integrated approach of this type would appear to be more reasonably applied
to new motor vehicles, on which the device could be incorporated as a part of
the original production configuration.
6-42
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6.1.5 Device 464: Methanol Fuel Conversion with Catalytic Converter
This device consists of an American Motors Corporation Gremlin modified to
run on methanol fuel and with a Device 292 catalytic converter installed. The
existence of this device was discovered too late in the retrofit study to make
a complete cost and effectiveness evaluation. The following summarizes data
obtained from EPA emission tests and from coordination with the Amsco Division
of Union Oil Company, a producer of methanol (References 62 and 63).
6.1.5.1 Physical Description
The methanol-fueled vehicle had a 232-CID six-cylinder engine and standard
three-speed transmission. The carburetor jets were modified so that the vehicle
could operate on methanol. The intake manifold was modified to supply additional
heat to the air-fuel mixture. A Device 292 catalytic converter (described in
paragraph 3.1.2) was installed in the exhaust system about six inches from the
exhaust manifold. (1).
6.1.5.2 Functional Description
The use of methanol as fuel was the fundamental approach used in this method
for controlling exhaust emissions. Since methanol is a paraffin hydrocarbon of
the methane series, it would inherently be less reactive and therefore less
polluting than gasoline. Because it boils at a relatively low temperature
(146°F), it would also provide better air-fuel mixing Dualities and be more
easily convertible to the gaseous state necessary to achieve combustion eff-
iciency. Air-fuel mixing and conversion of the methanol to a gaseous state
would be enhanced by the intake manifold modification. The catalytic converter
would further oxidize these pollutants downstream of the combustion event.
6.1.5.3 Performance Characteristics
Device 464 was tested by EPA for emission reduction effectiveness using the
1972 Federal Test Procedure and the 7-mode procedure. Additional tests were
performed to characterize the chemical composition of the exhaust emissions.
Tests were performed with gasoline to establish a baseline with the reactor
installed. Tests with methanol as fuel were performed with the catalyst re-
moved, to establish the emission level with methanol only. The emission test
results for the 1972 Federal Test Procedure are summarized in Table 6-16.
These results indicate that methanol has better emission reduction effectiveness
with the reactor than without, but that gasoline with the reactor is better for
HC and CO but not for NOx. Overall, the methanol fuel with reactor comes closer
to meeting the 1976 Federal standards of 0.46 gm/mi HC, 47 gm/mi CO, and 0.4
gm/mi NOx. Methanol indicates much better NOx control than gasoline.
(1) This vehicle was also equipped with an EGR system, which was not operated
during the emission tests.
6-43
-------
Table 6-16. DEVICE 464 EMISSION TEST RESULTS
(REFERENCE 62)
VEHICLE
CONFIGURATION 2)
1. Gasoline Fuel
with Reactor (3)
2. Methanol Fuel
with Reactor (1)
Percent Reduction
over Item 1
3. Methanol Fuel
without Reactor
Percent Reduction
of Item 2
Percent Reduction
of Item 1
Percent Reduction
of Item 2
POLLUTANT (GM/MI)
HC
0.34
0.45
-32
1.33
66
74
50
CO
5.44
6.82
-25
10.8
37
50
16
NOx
4.74
0.24
95
0.45
47
-91
97
(1) Average of six standard 1972 Federal Tests (Reference 3)
(2) American Motors Corporation Gremlin
(3) One 1972 Federal Test
(4) Calculated by assuming that the percentage reductions of
Item 2 over 1 represent the basic percentage differences
between gasoline and methanol emissions for the vehicle
tested.
The exhaust composition tests (reference 62) indicated that methanol constitutes
95 percent of the pollutants being emitted from the exhaust with methanol as fuel,
This indicates that with methanol as fuel, photochemical smog attributable to
vehicle exhaust emissions would be practically eliminated. The composition
tests also indicated that the catalytic reactor mainly decreases exhaust emis-
sions of methanol (90 percent) and CO (70 percent), but has relatively no effect
on NOx. Therefore, the large reduction of NOx shown for Item 2 of Table
6-16 appears to be attributable to the methanol itself.
6-44
-------
6.1.5.4 Reliability
The effects of methanol on engine life were not noted in Reference 62. Since methanol
contains no lead, it would eliminate the problem of converter catalyst degrada-
tion which occurs with leaded gasoline.
6.1.5.5 Maintainability
Assuming that methanol does not adversely affect engine components, or catalyst
life, there should be no special maintenance required for Device 464.
6.1.5.6 Driveability and Safety
Since the test vehicle, as modified, was the winner of the Liquid Fuel Division
of the 1970 Clean Air Race, methanol apparently has satisfactory driveability
characteristics. Being a poisonous chemical, however, methanol in widespread
use might present safety problems. The toxic effects of methanol inhalation by
humans and animals were not investigated .
6.1.5.7 Installation Description
The installation of Device 464 requires a carburetor modification and catalytic
converter installation. The latter is described in paragraph 3.1.2.7 for the
Device 292 converter used in the test vehicle. The carburetor modification
could be accomplished in accordance with standard carburetor overhaul kit
procedures. The total installation time is estimated to be 3.5 hours, adding
the converter tune of 1 hour (Table 3-12) to the carburetor modification and
tuning time of 2.5 hours.
The specific modification made to increase intake manifold heat is not known,
and therefore is not included in the installation time estimate.
6.1.5.8 Initial and Recurring Costs
Initial and recurring costs for the Device 292 catalytic converter were esti-
mated to be between $75 and $85 (see Table 3-13 for assumptions). If only one con-
verter were required then costs would be approximately $40. (1)
The lower cost per gallon of methanol over gasoline could reduce the recurring
costs assuming that fuel consumption with methanol would be equivalent to
gasoline. In bulk quantities of over 6,000 gallons, methanol can be bought
for 18.5£ a gallon (Reference 63). If State and Federal taxes were added, the
cost per gallon would be approximately 28.5£.
(1) The specific cost of converting an engine to run on methanol is not known.
6-45
-------
6.1.5.9 Feasibility Summary
Methanol as vehicle fuel indicates effective NOx reduction and, when combined
with a catalytic converter, is also effective for HC control along with rela-
tively smaller decrease of CO. Methanol would eliminate the lead contamination
problem associated with the gasoline-and-catalytic-converter emission control
combination. The effect of methanol on engine life, particularly that of older
engines, would have to be determined first. For some limited application, the
existing supply of methanol may be adequate, although this was not verified as
part of the retrofit study.
The overall determination of the feasibility of methanol as a motor vehicle fuel
would have to include consideration of its toxic effects on human and animal
life.
6-46
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6.1.6 Device 460^ Compressed Natural Gas Dua^L-Fuel Conversion
This device is in production, and is the natural gas version of Device 52,
which was described for LPG applications in paragraph 6.1.1. The device has
been accepted by the California Air Resources Board as meeting California
emissions standards, and is eligible for State road tax refund on natural gas
of 7
-------
Table 6-17. COMPRESSED NATURAL GAS TANK
CHARACTERISTICS (REFERENCE 46)
Capacity
(standard @
cubic feet)
375 @
325 @
312 @
85 @
303 @
? 9
Fill
Pressure
fpsi)
2400
2400
2265
2250
2400
2400
Size (less valve)
Diam. x Length
9%" x 55"
10"x43"
9%"x51"
7" x 24"
1C"x40"
10"x37"
Weight
(Ibs.)
135
f 08
120
27
?
?
Cost
S83.27
111.58
75.57
42.92
less than
111.53
less than
111.58
6.1,6.2 Functional Description
The principal functional component of the CNG dual-fuel system is the
mixer, which mounts on the gasoline carburetor intake as a replacement for
the production air cleaner. The mixer can be supplied with natural gas through
a system of regulators and valves from either pressure cylinders or liquefied
natural gas tankage - in the latter case, a heat exchanger would be required
to vaporize the natural gas (Reference 69). No internal engine modifications
are required. Spark timing is usually readjusted slightly to obtain minimum
exhaust emissions during both natural gas and gasoline operation.
As for the Device 52 carburetor described in paragraph 6.1.1.2, the CNG carbur-
etor operates on the diaphragm controlled, variable venturi principle. It
meters the required quantity of natural gas into the carburetor air stream
over the full range of engine airflow demands. The one Device 52 model covers
the full range of engine sizes. The adjustment procedure is the same for all
engine sizes and consists of two steps (Reference 69):
a. Adjust the final pressure regulator to deliver natural gas at a
pressure between +0.5 inch of water when the engine is
operating under a light load.
b. Adjust the mixer idle screw to the lean drop-off point.
At these settings, the carburetor maintains a lean mixture with approximately
25 percent excess air.
The gasoline carburetor functions when the mixer is placed in the "gasoline"
configuration. This is accomplished by pulling the Bowden cable control
on the vehicle dash. Electrical selection of the proper fuel is coordinated
with the mixer cable control, through the solenoids in the CNG and gasoline
fuel lines.
6-48
-------
(a) CNG Tank Set
(b) CNG Carburetor
Figure 6-12. DEVICE 460 COMPRESSED NATURAL GAS DUAL FUEL CONVERSION SYSTEM
INSTALLED ON A CHRYSLER NEW YORKER (REFERENCE 68)
A photograph of the operator controls is shown in Figure 6-13. A gauge monitors fuel
tank pressure and a pilot lamp flashes on when switching modes of operation. Oper-
ations such as starting, stopping, and accelerating, are the same whether operating
on gasoline or CNG. Filling of the CNG tanks is accomplished from a gas-storage fa-
cility. The CNG fill-valve is located in the vehicle's engine compartment for han-
dling ease and safety reasons (Reference 103).
Figure 6-14 shows the functional flow of a typical CNG-gasoline dual-fuel system.
The CNG flows from the tanks through the regulators and the gas-air mixer into the
carburetor. The two stages of regulation reduce fuel pressure to 55 psig and finally
to 0.7 psig before the gas is admitted to the mixer.
Since enough CNG cannot be compressed to operate a vehicle over extended distances,
the dual-fuel system is frequently used so that the vehicle can proceed on gasoline
when the CNG is expended. Under the extremely low temperatures and vacuums
obtainable with cryogenic techniques, natural gas can be liquified. In this state,
enough natural gas can be stored in a 15-to-20 gallon tank to operate a vehicle
for the distances possible with gasoline. The special vacuum wall tanks required
to store liquified natural gas at the required low temperatures (between -258.8
and -116F) presently sell for about $400 (Reference 30).
Natural gas is more frequently stored in the compressed gaseous state, in high-
pressure steel cylinders like those used for storing other compressed gases.
In these bottles, natural gas can be stored at ambient temperatures; however,
the amount of gas that can be compressed in one of these bottles, even at
2,200 psi, is only equivalent to about 3 gallons of gasoline. Thus more than
one cylinder is required. Since each one weighs 130 pounds when full (about
the same as a full gasoline tank), and occupies over 2 cubic feet of space,
most of the trunk space of a passenger vehicle is required to store compressed
gas to drive 100 miles.
Figure 6-12 shox^s a typical set of CNG tanks installed in a vehicle. The six
tanks store enough fuel for about 100 miles. These cylinders cost about $60
each (Reference 30). Since this price is based on existing mass production
of the cylinders it would not be likely to decrease much if more vehicles were
equipped for use of natural gas.
6-49
-------
6.1.6.3 Performance Characteristics
In the EPA program reported in Reference 67, two vehicles were tested (a 6-cylinder
Chevrolet and a Ford pickup truck) with Device 460 installed. Table 6-18 summarizes
exhaust emission results obtained using the 1972 Federal Test Procedure with the
vehicles operating first on gasoline and then on CNG. Emission increases of CO and
NOx were measured on the Ford Test Vehicle.
Table 6-18. DEVICE 460 COMPRESSED NATURAL GAS DUAL-FUEL CONVERSION
EMISSION TEST RESULTS (REFERENCE 67) (1)
VEHICLE
CONFIGURATION
Chevrolet
Ford
Percent Reduction (3)
POLLUTANT (GM/MI)
HC
CNG
2.1
3.0
Gasoline
(2)
3.0
0
CO
CNG
3.8
25.0
Gasoline
(2)
21.0
-19
NOx
CNG
2.0
4.6
Gasoline
(2)
2.8
-64
(1) Results from 1 test using standard 1972 Federal Test Procedure (Ref 3)
(2) Not tested
(3) Percent reduction calculated on Ford only, as no baseline for the Chev
In 1969, an extensive test program was conducted by the Device 460 developer to quali-
fy the dual-fuel system for California acceptance (Reference 69). Most of the testing
was performed at the California Air Resources Board Emission Test Laboratory. Table
6-19 summarizes the results of this program.
The high percentage reductions shown in Table 6-19 for all three pollutants with CNG
as fuel were obtained using the California 7-Mode test procedure (Reference 41). The
test report indicates that sometimes it was necessary to retard the spark timing.
Emissions recorded during the test indicated the emission levels with CNG are con-
6-50
-------
Figure 6-13. CNG INSTRUMENT PANEL CONTROLS
(REFERENCE 103)
,
FIGURE 3
1. Fuel Cylinder
2. Positive Fuel Shut Off Solenoid
3. Primary Regulator
4. Primary Regulator Test Point
5. Natural Gas Fill Valve and Pressure Safety Valve
6. Cylinder Refill Line
7. Natural Gas Solenoid Valve
8. Secondary Regulator
9. Secondary Regulator Vent Line
10. Accelerator Vacuum Line
11. Vapor Hose
12. Dual Fuel Systems Gas Air Mixer
18 19 20
gasoline supply
.
.
18.
'••
20.
21.
Mixer Adapter
Carburetor
Gasoline Solenoid Valve
Wiring Harness
Vacuum Switch
Fuel Selector
Natural Gas Gauge
Fuel Selector Indicator Light
Fuel Pressure Safety Restrictor Fitting
Figure 6-14.
CNG DUAL-FUEL CONVERSION SYSTEM FUNCTIONAL SCHEMATIC
(REFERENCE 46)
6-51
-------
Table 6-19. DEVICE 460 CNG DUAL-FUEL CONVERSION
EMISSION TEST RESULTS (REFERENCE 69)
AnenduJ September IS, 1969
,
Clad s Din placement
Cubic Inch Tr« tunica Ion
a
0-140
b
140-200
c
200-250
J
250-100
i
3CC-375
f
375 •+•
1969 Jeep 4
134 cu. In.
Manual
1369 Rflnbl. 6
KaOUJ.1
1968 Chev. 6
250 cu. in.
Manual
1568 Ford 8
289 cu. in.
Automatic
1969 Ford 8
302 cu. In.
Automatic
1967 Chrys. 8
440 cu. in.
Automatic
Test
Baseline
At conversion
After 4,000 Kl
Case line
After 4.000 Hi
Baseline
At conversion
After 4,000 Hi
Baseline
At Conversion
After 9,000 Ml
Baseline
At conversion
After 4,000 Ml
Baseline
At Conversion
After 4,000 Hi
Carbon Monoxide
CMaJ-lftt~ Hat. Gas- fig
I
1.97
1.97
.59
2.45
2 34
3.21
1.07
1.16
.96
1.3
. ':5>
i.u
.86
.56
2.20
1.66
2.26
Percent Reduction
NOT.-!;
(1) Oa
(2) Ka
Data are continuou
fiollnc emissions are
t ura I aai emiaiiiona
t
.
.15
•22
09
.12
.
.15
.17.
„
.12'
.13
_
.22
.20
,
.15.
.13.
90 '
e HDIR except Reactivity Units which are fron
for cold start sequence,
ara from hot ntart cvcles.
Hydrocarbon.
Concentration Reactivity unite
iiinUr.^i' Hat. GceZ/ O.i'nltne Nat. Caal/
ppu
393
321
365
417
348
378
709
418
248
273
233'*'
471
271
342
272
178
158
51
I P.I.D. teet
ppm
.
158
218
106
74
_
168
123
.
118
97
.
130
185
_
547
79
a on
Unite
15SO
1165
1320
2420
2C65
1975
1950
2330
1345
_
_
1370
2370
2940
1855
1455
1815
1470
bag eaioplee.
except ae noted In footnote (4), corrected to 15
corrected Co 11 T CO?. Previoue teet data ehov
Unite
.
35
270
225
175
_
205
160
.
„
86
.
285
190
_
270
175
I C02-
toldeB of Nlcrcgtn
UoncenCi'lEl
GaEollnci Net
P?»
1079
1100' '
1439
1245
855
840
1279
679
522
736
1476 (4
15S11
1051
491
600 <5>
1200«>
434
477
71
:oTi
pp»
27S
411
359
359
.
!£»
_
570
110<5J
.
122
172
_
'.10 t;.
J'JJ'-l
and hot starts. Table IV.
O) Reactivity Units for tuitural gag
(,';} Mot Start cycles.
(5) Oxides oC nitrogen derived from bag Bamples
Table 6-20. DEVICE 460 CNG HYDROCARBON REACTIVITY (REFERENCE 69)
Gasoline
Natural Gas
C1.1GS
1*0-200
00-2 SO
d
250-300
300-375
f
375
Yr/Malte/Cyl
TransraisBion
1969 Je2p *
134 cu. In.
Manual
1S«9 Rttmb. 6
199 cu. in.
Hsnujl
1963 Chev. 6
250 cu. in.
Manual
1963 Ford 8
209 cu. In.
Automatic
1969 Ford 8
302 cu. in.
Automatic
1967 Chrys. 8
440 cu. in.
Automatic
Test
Conditions
Baseline
At conversion
After 4000 Mi.
Basell ne
At conversion
After 4000 Mi.
Baseline
At conversion
After 4000 Mi.
Baseline
At conversic-i
After 9000 Mi.
Baseline
At conversion
After 4000 Ml.
Baseline
At conversion
After 4000 Mi.
Concentrations
Far.
ppn
230
185
160
390
475
205
370
475
225
..
-
230
330
340
270
125
155
UQ
Ole.
ppm
110
10
100
175
165
165
115
125
95
_
-
105
195
250
140
140
155
140
Aro.
ppm
160
140
120
210
90
150
220
235
120
.
.
100
160
200
155
70
140
80
1-8-3
Resc tlvi ty
Units
1590
1165
1320
2420
2065
1975
1950
2330
1345
_
-
1370
2370
2940
1855
1455
1815
1470
Concentrations
Par.
ppm
270
265
380
185
470
250
Ole. Aro.
ppm ppm
4
30
27
22
20
17
260 20
600 30
440 23
1
10
15
8
15
2
820 30 10
240 30 0
1-8-3
Reactivity
Units
305
535
599
361
675
410
420
885
630
1130
480
0-0-3
Reactivity
Units
35
270
225
176
205
160
160
235
190
270
240
6-52
-------
sistently low from cold to hot test cycles. This apparently is attributable to the
even diffusion of the air-fuel mixture whether the intake manifold is hot or cold.
This is characteristic of gaseous fuels. For this reason, a choke is not required
during cold start, as with gasoline, which does not diffuse well during cold start
because of its liquid state.
Because of the uniform mixture distribution of CNG and the excess of air provided
by the carburetor, the low carbon monoxide emission level is an expected result.
The exhaust hydrocarbon concentrations shown in Table 6-19 indicate substantial re-
ductions when converting from gasoline to natural gas, but do not reflect the change
in nonreactive hydrocarbon compounds with natural gas fuel. As noted in the Refer-
ence 69 test report, methane is the primary constituent both of natural gas and the
exhaust hydrocarbons resulting from natural gas combustion. Methane has indicated
zero reactivity in measurements of photochemical smog production known to date.
This pattern is consistent with methane's paraffinic stability. The gas chromo-
tographic data obtained in the Reference 69 program indicated that the paraffinic
component of natural gas is almost pure methane; and that when another paraffin is
found, it is ethane, which is nearly as nonreactive as methane. Gasoline, in com-
parison, has a preponderance of olefin and aromatic compounds that are long chain
with high photochemical reactivity.
A benefit of Device 460 (and of any gaseous fuel system) is that hydrocarbon emissions
from carburetor and gas tank fuel evaporation are nearly zero because of the sealed
gaseous fuel system. The gasoline carburetor is dry when operating on natural gas,
and consequently gasoline hot soak emissions are zero.
According to the Reference 69 report, the low NOx emission levels with CNG are attri-
butable to the high air-fuel ratios achievable with CNG, which can operate at
air-fuel equivalence ratios on the order of 20 percent higher (for given throttle
settings) than gasoline (Reference 124).
6.1.6.4 Reliability
Device 460 CNG-gasoline dual-fuel systems are in widespread use nationally. The rate
of usage is increasing. During 1970, it was estimated that CNG conversions increased
from 100 to 3,000 (Reference 68). Most of these conversions have been made on fleet
vehicles, including passenger cars, trucks, tractors, and sweepers. Some of these
vehicles average 20,000 miles per year (Reference 46). Based on this fleet usage
data, it would appear reasonable to assume that a Device 460 system would have several
vehicle life times of reliability. For the performance analysis of Volume III, a
300,000-mile reliability was assumed.
6.1.6.5 Maintainability
Based on the system configuration shown in Figure 6-14 and available data, it was
assumed that no periodic maintenance attributable solely to the Device 460 system
would be required. As for LPG (paragraph 6.1.1.5), maintenance histories reported
by CNG-gasoline dual-fuel system users indicate substantial savings in overall
engine maintenance through this type of conversion.
Maintenance data reported by the General Services Administration (GSA), Washington,
D.C. (as summarized in Reference 46) indicate recurring cost savings ranging from
10 to 60 percent in vehicle maintenance, due to reductions in oil changes, oil
filters, and tuneups. Overall fleet maintenance cost was reduced by 36.6 percent.
6-53
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6.1.6.6 Driveability and Safety
As noted in Reference 30, peak power output of a spark-ignition engine is reduced by
approximately 10 percent when the fuel is changed from gasoline to methane (CNG).
This power loss is attributed to the reduced volumetric efficiency of gaseous fuel.
As for propane, the brake specific fuel consumption (pounds of fuel consumed per
brake horsepower hour) is less than that for gasoline. Reference 30 reported that
a 13 percent reduction in specific fuel consumption has been measured on CFR engines
when the fuel is switched from gasoline to methane. This is attributable to methane's
higher heat energy per pound than that of gasoline (23,900 Btu/lb. methane compared
to 20,500 Btu/lb. gasoline).
It is generally accepted that 100 standard cubic feet (SCF) of CNG equals 1 gallon
of gasoline in Btu/lb. (Reference 30). Since only about 325 SCF can be stored in
the average CNG cylinder at 2,265-2,400 psi, the driving distance of a vehicle on a
single CNG tank like this would be equivalent to that for about 3 gallons of gaso-
line; or, at 12.5 mpg for gasoline, 37.5 miles. Four of these large size tanks
would provide enough fuel for only about 160 miles. Because of its lower specific
gravity compared to gasoline's, twice as much methane would still be required in the
liquid state to equal gasoline's Btu/gallon heat energy. The principal physical
properties of gasoline and methane are as follows:
Boiling Specific
Point (°F) Btu/Lb. Btu/Gal. Gravity
Gasoline 100 20,747 123,000 0.7
Methane -259 23,861 61,000 0.3
An example of the slightly.reduced vehicle performance resulting from CNG use is the
acceleration test reported in Reference 103. Acceleration performance measurements
were made on a quarter-mile drag strip using a 1971 Ford Mustang with a Device 460
dual-fuel conversion. After five runs were made on CNG, the vehicle was switched
to conventional fuel operation and two runs were made on gasoline to obtain a com-
parison. The elapsed time and speed at the end of each run and the overall averages
are shown in Table 6-21. Vehicle acceleration when operated on CNG showed a de-
crease in performance in comparison to gasoline with an 11 percent increase in
elapsed time and a 7.6 percent decrease in speed. This slight loss of acceleration
is the only reported driveability penalty found for CNG in the retrofit study.
Safety does not appear to be a problem with CNG, despite the high pressures at which
it must be stored. The Department of Transportation Specifications DOT-3A and 3AA
require testing of the gas cylinders at 5/3 times service pressure every five years
(Reference 46). DOT also requires that each CNG cylinder be equipped with approved
safety relief valves, if charged to 1,800 psi or higher at 70F.
The high ignition temperature of CNG (1,300°F compared to 600°F-700°F for gasoline)
reduces the possibility of accidental fire should leakage occur. Since methane is
lighter than air it would rise, further reducing safety problems. Reference 46 re-
ported a crash test in which 25 fuel cylinders were dropped tested in many different
but normal tiedown configurations on a vehicle from a height of 46 feet (equivalent
to 30 mph head-on collision). Only three tanks shifted in their mountings and none
ruptured. A CNG tank normally incorporates a safety burst disc that vents the tank
if 3,200 psi is reached.
6-54
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Table 6-21. DEVICE 460 ACCELERATION TEST RESULTS WITH A 1971 FORD MUSTANG
(REFERENCE 103)
RUN NO.
1
2
3
4
5
Average
6
7
Average
FUEL
CNG
CNG
CNG
CNG
CNG
CNG
gasoline
gasoline
gasoline
Percent Change
ELAPSED TIME
(SECONDS)
19.26
19.09
20.18
19.30
19.01
19.37
17.45
17.47
17.46
-11
SPEED (MPH)
70.75
71.20
70.47
70.75
70.97
70.83
76.40
76.92
76.66
7.6
6.1.6.7 Installation Description
It is assumed that a CNG-gasoline dual-fuel conversion made for retrofit purposes
to control vehicle exhaust emissions would have to meet rigorous installation re-
quirements such as those presently being considered in California (Reference 50).
On this basis, the installation requirements for a Device 460 conversion would be
similar to that described for the Device 52 LPG system in paragraph 6.1.1.7. The
principal difference would be in the system components. For Device 460, these
would consist of the CNG tanks, fuel line, two pressure regulators, the mixer,
solenoid valves to control the flow of gaseous fuel or gasoline, and the Bowden
control cable.
Detailed instructions for installing these components are presented in Reference
104. The CNG tanks are mounted on two wooden runners with steel straps and bolted
through the trunk floor using 1/2-inch bolts and backup plates. Cylinder mounting
brackets and clamps are used for a permanent installation.
The pressure regulators are mounted on the left front side of the engine compart-
ment. Normally the mixer is installed directly onto the carburetor after re-
moval of the standard air cleaner. In some installations, the lack of hood clear-
ance may necessitate the use of an offset adapter to connect the gas-air mixer with
the carburetor.
The remaining installation, engine tuneup and test requirements are analogous to the
Device 52 installation. It is estimated that 12 hours would be required for this
installation. Garages and mechanics certified for this type of installation should
be used.
6-55
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6.1.6.8 Initial and Recurring Costs
The basic components required for a Device 460 conversion would cost approximately
$300, not including the fuel tanks (Reference 30). For a light-duty vehicle dual-
fuel retrofit installation, it is assumed that at least two fuel cylinders would be
used. This would provide enough fuel for a driving range of about 75 miles, after
which the vehicle would be switched to gasoline. This should enable a vehicle to
be operated on CNG most of the time in metropolitan areas, in which exhaust emis-
sion control requirements are generally most critical.
As shown in Table 6-17, a 312 cubic foot tank would cost about $75. Overall installation
costs would therefore be approximately $600. Over a 50,000-mile service life, this ini-
tial investment would be recouped by recurring cost savings as indicated in Table
6-22. The major savings are in reduced fuel costs and engine oil changes and tune-
ups. Fuel cost per 100 SCF (equivalent to one gallon of gasoline in Btu/hr.) was
estimated to be 16c, based on California rates (Reference 28), including 7c per
100 SCF State road tax refund.(1) Savings on oil changes and tuneups were based
on the reduced requirements indicated for LPG (Table 6-10), since gaseous fuel
benefits with respect to reduced engine maintenance appear to be about the same.
For the savings in fuel costs, it was assumed that the vehicle would be operated on
CNG 50 percent of the time over a 50,000-mile service life. This assumption is
based on the transient modes of operation reported in Reference 30 for the New Jer-
sey Cycle pattern of vehicle operation, in which transient modes occur approximate-
ly 47 percent of the time. These modes contribute heaviest to vehicle exhaust
emissions and are therefore the ones during which the CNG phase of a dual-fuel
system would be most likely used.
6.1.6.9 Feasibility Summary
Although either natural gas and propane can be used in dual-fuel applications with
gasoline, both dual-fuel systems have been found to compromise engine performance.
The gasoline engine design is optimized for gasoline and even sole use of a gaseous
fuel instead of gasoline does not provide the same level of performance as gasoline.(2)
The performance penalty is not severe, however, compared to the benefits in reduced
emissions. Natural gas produces about one-fourth as many harmful pollutants as gaso-
line (Table 6-20).
(1) See Footnote, page 6-3.
(2) In tests reported in Reference 26 it was found that the gasoline engine pro-
duces 14.6 percent less power with CNG, although BSFC predicts essentially
equal thermal efficiency for gasoline and CNG. The difference in power out-
put was attributed to the difference in fuel density. The gaseous fuel re-
places more air volume flow than gasoline and in effect lowers the engine's
volumetric efficiency. The Reference 26 program also indicated the per-
formance compromise inherent in a dual-fuel system, in that it was found that
CNG requires about 5 degrees more spark advance than gasoline for a minimum-
for-best-torque (mbt) spark advance. It can be seen that a dual-fuel car
timed for gasoline would run with retarded timing when operated in CNG; or,
conversely, if timed for CNG would be over-advanced for gasoline. The effective
retard for CNG running at the mbt for gasoline would be perhaps 5 degrees more,
since in the normal installation CNG operates at a much leaner air-fuel ratio
(19:1) than the leanest-for-best-torque (Ibt) ratio. Dynamometer tests per-
formed on CNG in the referenced program showed that mbt spark advance at 19:1
air-fuel increases by another 5 degrees over Ibt operation.
6-56
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Table 6-22. DEVICE 460 CNG DUAL-FUEL CONVERSION INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Dual-fuel
conversion kit
2. Fuel tanks
Labor
1. Engine tuneup,
kit installation,
checkout, and
test.
DESCRIPTION
Refer to par.
6.1.6.7
9.25 by 51
inches, 312-SCF
capacity at
2,265 psi, and
120-pound weight
each.
Refer to par.
6.1.6.7
LABOR HOURS OR
ITEM QUANTITY
Approximately
$300.00
$75.57 each
(Table 6-17)
12 hrs. @
$12.50 per hr.
COST .
(DOLLARS)
300.00
151.14
451.14
150.00
Total Initial Costs 601.14
50,000-Mile Recurrin
Material Savings
1. CNG Fuel Economy '
Fuel
Gasoline
CNG
2. Oil Change
and Tuneup
Savings
g Costs: (Estimated sav
dual-fuel sys
Versus Equivalent Gasolii
Miles /Unit Volume
12.5 mpg
12.5 mi./ 100 SCF
Fuel Savings
50 percent of savings
for LPG in Table 6-10
(2)
ings by converting to C
tern)
le Consumption (1)
Vol. 750,000 Mi. $/Uni
2,000 gal. X 0.357;
200,000 SCF X 0.16/
= $700.00
= 320.00
$380.00
Oil = .50 X $123.00
Tuneup = .50 X $120.01
NG-gasoline
t Volume
5al. =
LOO SCF =
- 380.00
- 61.50
) - 60.00
Total Recurring Cost Savings 501.50
TOTAL COSTS 99.64
(1) Based on the Btu/hr. equivalency of gasoline and CNG, one gallon of gasoline
is assumed equivalent to 100 SCF CNG. Assuming that CNG would be used 50 per-
cent of the time over a 50,000-mile period and that average miles per unit of
equivalent volume is 12.5 for both fuels (based on an assumed national aver-
age of 12.5 mpg for gasoline), 2,000 gallons of gasoline and 200,000 SCF of
CNG would be required for a vehicle to be operated 50,000 miles on a dual-fuel
basis. The $/unit volume are based on averages assumed for the retrofit study.
(2) Assuming that CNG offers maintenance benefits equivalent to gasoline, but
would be used only 50 percent of the time in a dual-fuel system. !
6-57
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The significant problem with use of CNG as a vehicle fuel is its lack of sufficient
supply for that application. It has been estimated that a complete switch to CNG
from gasoline, for all motor fuel requirements, would require the natural gas in-
dustry to triple its size by 1982 (Reference 47). As compared to the more than 100
million gasoline vehicles operating in the U.S. at the end of 1971, there were ap-
proximately 250,000 LPG and 3,000 NG vehicles (Reference 31). The use of natural
gas as a vehicle fuel is insignificantly small compared to the total primary consump-
tion of natural gas in the U.S. (23.3 trillion cubic feet forecast for 1971). The
total supply of natural gas projected through 1990 would not be sufficient to meet
future requirements'presently estimated on the basis of no substantial variation in
the percentage of vehicles using natural gas.
The supply deficiency is attributable to the fact that the price of natural gas being
regulated Federally at the wellhead is too low to provide the economic incentive for
the exploration and drilling necessary to produce additional supplies of gas (Refer-
ence 32). The proving out of additional supplies is an essential part of the natural
gas supply situation, in that the Federal Power Commission requires a 20-year supply
of gas from proved reserves as backup to any contract for the delivery of natural gas
in interstate commerce. The reserves needed presently exist in the form of "future
discoveries." Some price adjustment would be needed for natural gas if these re-
serves were to be brought into the "proved" category so that the supply of natural
gas would be adequate for widespread use of natural gas as a vehicle fuel. An in-
crease in wellhead price to stimulate increased natural gag production probably would
not offset the current trend toward supply deficiency until 1975 (Reference 30).
Though a sufficient quantity of natural gas could be provided eventually, it is
doubtful whether the required increase could be accomplished within the retrofit time
frame of the next 10 years. The required growth to support a major CNG retrofit pro-
gram would be far below the expected decline in natural gas production from the 1968
growth rate of 5.5 percent to 4 percent per year through 1975.
The following is a quotation from Reference 28 on the availability of natural gas
for vehicle fuel conversions:
"Powering all California motor vehicles with natural gas would necessitate
a 42% increase in supply. Powering all fleet vehicles would require a
more modest increase of 4%.
"The natural gas available to California is currently unable to supply all
power plant and other usage during the winter months. This is likely to
continue for the next few years. Transportation of liquified natural gas
by ship began about 1964 and is being expanded rapidly. Oversea trans-
portation holds promise to meet future demands for natural gas."
Without economic incentives, the industry output may decline further after 1975
(Reference 30). Since all pre-1973 gasoline-fuel vehicles could be retrofitted
with CNG it does not appear that such widespread use of CNG-fuel would be feasible,
because of the inability of the natural gas industry to respond and still supply
its firm residential and commercial users. Some compromise use of natural gas would
have to be made if it were applied as a retrofit approach. The use of a dual-fuel
conversion would be a possible compromise. Also use might be limited to certain
fleets of vehicles or to vehicles within prescribed geographical areas where air
quality standards cannot be met due to excessive vehicle emissions.
6-58
-------
Though the initial cost of a dual-fuel conversion is high, a large economical ad-
vantage of gaseous fuel is the reduction in engine maintenance and lower fuel cost.
The reduced dilution and contamination of oil could be expected to extend oil change
intervals and reduce engine wear. CNG is clean burning and produces no lead, var-
nish, or carbon deposits. Thus spark plugs should stay cleaner much longer and the
engine should not load up with sludge. With the anticipated maintenance and fuel
reduction advantages, it is estimated that the initial costs of installation could
be recovered in six years, or sooner, depending on the average mileage driven
(Table 6-22). It would appear to be more advantageous to the vehicle owner to ob-
tain the economy of maintenance of an LPG or CNG system while emissions are being
reduced, rather than to have a gasoline engine which has been detuned to reduce
emissions to the point where performance is marginal. The low maintenance factor
also is important because the longer the engine stays clean and in tune, the longer
the emissions are reduced to the acceptable level (Reference 103).
It should be noted that an increase in demand for CNG could cause an increase in
cost; however, any such increase could be offset by legislation exempting con-
verted vehicles from road use taxes.
The alternate fuels project reported in Reference 103 indicated that exhaust emis-
sions may be lowered significantly by conversion to CNG without major engine adjust-
ments. Further reductions in emissions may be obtained by the same methods used
for gasoline operation, such as retarding the spark and leaning the fuel mixture.
However, the same sacrifice must be made as on gasoline: a decrease in performance.
Because of the shortage of CNG for full scale retrofit applications, the best
approach for utilization of the potentially available supply sould appear to be for
the automobile manufacturers to offer the option of new car conversions to LPG and
CNG systems and for fleet vehicles to be converted on a retrofit basis in sleeted
air quality control regions. If done exclusively as a single-fuel conversion, this
would allow the most efficient usage of carburetion and minor engine modifications.
Because of convenience and vehicle owner acceptance problems of these fuels, the
interim solution would be to offer dual-fuel LPG-gasoline or CNG-gasoline con-
versions. This compromise has the disadvantages of higher emissions and lower per-
formance. In particular, on a dual-fuel conversion involving gasoline, the emis-
sions during operation in t he gasoline mode are indicated as being higher than if
the engine had not been converted. This tends to nullify the emission reduction
gained during the LPG or CNG mode of operation. An approach which may deserve more
consideration in the future is the use of a dual fuel system consisting of combined
CNG/LPG operation. The carburetion and engine modifications common to both fuels
could be used without increasing emissions or decreasing performance, yet would
still allow the convenience of a dual-fuel system.
Another problem associated with the shortage of CNG supply for full-scale vehicle
conversions is the lack of general public retain distribution of CNG. Generally,
each fleet operator has designed his own refueling station (Reference 46). As
vehicle owner use expands, refueling stations would be required commensurately.
6-59
-------
Thus far, most gaseous fuel conversions have been made because of the fuel and main-
tenance economy benefits, rather than for emission reduction (Reference 34). As
noted in Reference 30, there are at least three factors which will influence the
rate of conversion for emission reduction purposes:
a.
wvs**V^-J.<-r^w*& 4- w 4. ^.mj. t? I*F .t. %_r i. L ^^.MVtWkO.V'llr kSVAA-fSV^i^WtJ •
Shifts in the relative prices of gasoline, compressed natural gas,
LNG, and propane.
b. Additional tax incentives and other legislated inducements offered
by government bodies.
c. Progress of the automotive industry in providing a "clean" car
using gasoline fuel.
Without some implementation of these factors, the rate of conversion of at least
commercial fleet vehicles would not be likely to tax the ability of gaseous fuel
suppliers or equipment manufacturers to supply the market demand.
A recent development stimulating conversions is the leasing of the gaseous fuel
equipment to the vehicle owner. Use of this approach would depend on individual
cases. In some cases, leasing of the equipment for a monthly fee over a specified
time period can provide the lessee a tax advantage not obtainable by purchasing
the equipment outright. The same applies to acquisition of onsite storage facilities.
If the lease arrangement is selected, the only investment cost to the lessee is the
cost of labor involved in the conversion. The monthly cost may be as low as $8 per
vehicle for the equipment used in the conversion, depending on the vehicle (Refer-
ence 30).
6-60
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6.2 FUEL ADDITIVE - RETROFIT SUBTYPE 1.4.2
This category of fuel modification devices approaches exhaust emission reduction by
adding compounds either directly to the gasoline fuel or to the air-fuel mixture in
the intake manifold. The objective in general is to modify the fuel mixture for
improved combustion and reduced emissions.
As shown in Table 6-1, four devices were studied in this category. For two of these
devices (182 and 282), data were obtained from the developers. For the other two
(457 and 465) , the sole data source was EPA.
6.2.1 Device 182: Fuel and Oil Additives
These additives are marketed products that are claimed by the developer, with some
test data substantiation, to decrease exhaust emissions of CO, HC, and NOx, and also
to provide fuel economy through reduced consumption. Less engine maintenance was
reported by the developer as an additional benefit. The developer guarantees a
5 percent fuel savings to any account, including the cost of the additives.
6.2.1.1 Physical Description
The developer described the additives as a "combination of hydrocarbon base fuel and
oil additives," and a "complex homogeneous mixture of petro-chemicals." The chemical
composition of the additives is apparently proprietary. They are sold in tube
quantities. Typically one tube of fuel additive is used for each tank of gasoline,
at a ratio of one part additive to 5,000 parts gasoline. Similarly, one tube of oil
additive is used in the crankcase, at a ratio of one part additive 'to 130 parts oil.
6.2.1.2 Functional Description
The developer claims that the additives are "formulated to restructure the hydro-
carbons in the fuel and oil. By restructuring the molecules so they burn more
efficiently they achieve the normally noncompatible result of additonal power and
increased fuel economy."
The principles of operation of the additives were not reported. One industrial user
was of the opinion that the fuel additive promotes "more complete combustion in the
quench zone near cold cylinder walls." He based this on the observation that var-
nish deposits on the cylinder walls were quickly removed with use of the additive.
Another user reported that he found no carbon deposits on the heads or intake valve
stems. A diesel user reported elimination of exhaust smoke, and indicated that the
smoke depressant normally used could be eliminated. Fuel mileage increases, reduced
oil consumption, and elimination of pinging with regular gasoline have also been
reported by users.
6.2.1.3 Performance Characteristics
Emission test data were provided by the developer from two independent test agencies.
Table 6-23 summarizes the results of tests performed by the City of Los Angeles.
Table 6-24 summarizes test results obtained by Olson Laboratories in tests performed
for the developer prior to the retrofit study.
6-61
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Table 6-23. DEVICE 182 FUEL AND OIL ADDITIVES EMISSION TEST RESULTS
REPORTED BY CITY OF LOS ANGELES (1)
VEHICLE
CONFIGURATION (2)
Without Additive
With Additive
Percent Reduction (3)
POLLUTANT
HC (PPM)
IDLE
143
60
58
2,500
RPM
52
13
75
CO (%)
IDLE
1.43
0.58
59
2,500
RPM
0.25
0.18
28
NOx (PPM)
2,500
IDLE RPM
(Not
measured)
(1) Results measured by Bureau of Transportation with a Sun Infrared Emission
Tester under dynamoneter steady state conditions at idle and 2,500 rpm.
(2) Four Plymouth Valiants, one Buick Special, and one Buick Electra.
(3) Average of six tests with and without additive.
Table 6-24. DEVICE 182 FUEL AND OIL ADDITIVES EMISSION TEST RESULTS
REPORTED BY OLSON LABORATORIES
ITEM
Percent Reduction
(1)
(2)
POLLUTANT
HC
26.2 (1)
CO
30.5 (1)
NOx
24.0 (2)
Average of four tests using the 1970 Federal Test Procedure on two 1968
and two 1969 Ford Fairlanes, with and without additive.
Result of one test using the 1970 Federal Test Procedure on a 1969
Ford Fair lane, with and without additive.
6.2.1.4 Reliability
The Device 182 additives were reported by the developer as having been used with nu-
merous types of vehicles for thousands of miles of operation with no failure attrib-
utable to the additives. Corrosion tests performed for the developer by Admerco,
Incorporated, Van Nuys, California, indicated that the additives are "essentially
non-corrosive to the materials tested" (copper, epoxy fiberglass laminate, galvanized
zinc, mild steel, and aluminum).
Additional testing was reported by the developer on a 4-cycle, single cylinder sta-
tionary engine driving an electrical generator. No engine damage was noted in 120
hours of operation both with and without the fuel additive. Cylinder wall deposits
were comparable in magnitude to engines not using the additive but the color was
white instead of black, which suggests the need for further testing.
6-62
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6.2.1.5 Maintainability
As a fuel additive, Device 182 would appear to require no maintenance action. The
developer provided a number of letters from users indicating improved engine per-
formance and cleaner operation, which might decrease engine maintenance. The quan-
titative data provided were insufficient to verify these claims.
6.2.1.6 Driveability and Safety
Based on the aforementioned user reports, Device 182 improves engine performance and
fuel economy. The developer reported that he has a one year contract to supply
McDonnell Douglas Aircraft Division, Long Beach, California, to treat all fuel for
its vehicle fleet. Fuel consumption data reported by McDonnell Douglas with and
without use of the additive indicate that fuel consumed with the additive is, on the
average, 18.4 percent less than untreated fuel. Table 6-25 lists the fuel consump-
tion data.
Since the chemical composition of the additives was not reported by the developer,
safety requirements with the device were not determinable.
6.2.1.7 Installation Description
The content of one tube of additive is added to each fuel tank of gasoline. The
additive is put in the tank first, followed by the gasoline, so that the two will
mix thoroughly. The oil additive is added through the engine oil spout.
Table 6-25. DEVICE 182 FUEL CONSUMPTION REDUCTION REPORTED BY
MCDONNELL DOUGLAS AIRCRAFT DIVISION (DEVELOPER SUPPLIED DATA)
WITHOUT
Vehicle
1-76
(Ford Truck)
1-78
(Ford Truck)
Ll-819
(Ford Van)
L-202
(IHC Scout)
L-203
(1 1IC Scout)
L3-222
(Buick
Sta .Wagon)
L3-223
(Buick
Sta. Wagon)
(1) Summary of
Test
Period
1/2-1/22
1/2-1/22
1/2-1/22
2/23-3/22
2/23-3/22
2/27-3/22
2/23-3/22
Test Results
ADDITIVE
Total
Miles
1514
927
1410
654
911
798
2091
1/2/70 -
Total Avg.
Gals. MPG
203.0 7.46
169.0 5.49
123.6 11.41
90.4 7.23
138,8 6.56
125.6 6.35
274.8 7.61
4/20/70.
WITH ADDITIVE
Test
Period
1/22-2/13
1/22-2/13
1/22-2/21
3/22-4/20
3/22-4/20
3/22-4/20
3/22-4/20
Total
Miles
1787
1180 ' ,
1972
634
890
1920
1665
Total
Gals.
216.8
170.0
163.7
73.9
99.4
265.4
Avg.
MPG
8.24
6.94
12.05
8.58
8.95
7.23
189.4 8.79
Average
Percent
Change
in MPG
10.54
26.5%
5.6%
18.6%.
36.4%
13.9%
15.51
18.4%
6-63
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6.2.1.8 Initial and Recurring Costs
Table 6-26 itemizes initial and recurring costs for the Device 182 fuel additive.
The only initial costs would be a vehicle tuneup for maximum emission reduction. As
indicated, the fuel savings indicated by the developer would offset recurring costs
by approximately $168 over a $50,000-mile vehicle service life.
Table 6-26. DEVICE 182 FUEL AND OIL ADDITIVES INITIAL AND RECURRING COSTS
ITEM
Initial Costs:
Material/Labor
1. Additive
DESCRIPTION
Device 182
LABOR HOURS OR
ITEM QUANTITY
$1.10 tube per 25
gallons
Total Initial Costs
50,000-Mile Recurri
Material
1. Fuel additive
2. Fuel savings
ng Costs:
Device 182 additive
Assumed average 12 percent
decrease in fuel consump-
tion based on developer
supplied data
$1.10/tube per 25 gal
gasoline X 4,000 gal.
over 50,000 mile
service life
480-gal. fuel reduc-
tion x $0.35 per
gallon over 50,000
miles (1)
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
$1.10
1.10
176.00
-168.00
$8.00
$ 9.10
6-64
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6.2.1.9 Feasibility Summary
Since the additives represented by Device 182 have not been subjected to complete
and formal emissions, driveability, and durability tests, the overall feasibility of
the device as a retrofit approach for vehicle exhaust emission control is considered
to require further substantiation. The data collected thus far indicate that addi-
tional study of the device should be made so that a definite determination of its
feasibility can be made. The simplicity of the approach and the savings indicated
by the developer in recurring costs could possibly make this device cost effective
when used in combination with other controls for vehicle exhaust emission reduction.
6-65
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6.2.2 Device 465: Fuel Additive
The sole source of information on this additive was obtained from an EPA exhaust
emissions test report (Reference 105). The developer of this additive was not
reported. Only limited evaluation of the additive's emission reduction effectiveness
was possible based on the available data.
EPA tested a 1962 Chevrolet Impala with and without the additives used. The
additives were mixed with Indolene 30 fuel as specified by the manufacturer.
Table 6-27 summarizes the test results obtained by EPA using the 1972 Federal Test
Procedure. Steady state emissions were also measured at 10-mph increments between
10 and 50 mph. The EPA report noted that the cyclic test results for the 1972
Federal Test Procedure differed considerably from that of steady state operation.
Steady state showed a significant increase in emissions, whereas the cyclic test
showed a reduction. Emissions measured under the 1970 Federal Test Procedure and
the EPA 9-cycle CVS procedure were also inconsistent with the Table 6-27 results.
The EPA report concluded that extensive testing would be required to determine
conclusively what the emission reduction effectiveness of the Device 465 additive
would be for the total vehicle population.
Table 6-27. DEVICE 465 EMISSION TEST RESULTS
(REFERENCE 105) (1)
VEHICLE
CONFIGURATION
Without Additive
With Additive
Percent Reduction
POLLUTANT (GM/MI)
HC
9.50
8.33
12.3
CO
112.30
101.19
9.9
NOX
4.15
3.81
8.2
(1) Result of one test using 1972 Federal Test Procedure (Reference 3)
on 1962 Chevrolet Impala with 283-CID V-8 engine and automatic
transmission, with and without additive.
6-66
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6.2.3 Device 282: LP Gas Injector
This device is intended to enable use of low octane fuel with high compression
engines without ensuing ignition spark knock (pinging). Propane is injected when the
vehicle is accelerating, passing, or pulling hard, to increase fuel octane and elim-
inate ping. This approach would reduce lead requirements for gasoline, thereby limit-
ing a source of pollutant byproducts. With this approach, the eventual use of cata-
lytic mufflers (which require low-lead gas) when pollution standards are increased
would not necessitate lower compression engines, which run less efficiently. The
retrofit unit is in manufacture, and it has been installed on 85 vehicles. Approx-
imately 600,000 miles of operation have been accumulated.
6.2.3.1 Physical Description
The principal components of this system are a regulator assembly, a manifold vacuum
switch, and an LP gas solenoid. Not supplied with the retrofit kit is the LP gas
bottle or the copper tubing to interconnect the system. System components are shown
in Figure 6-15. A functional diagram of the system is shown in Figure 6-16. The
components and accessories included in a Device 282 kit are:
a. Regulator with special spring, 1/8-inch pipe nipple, K-0 hose nipple
b. Manifold vacuum switch
c. 12-volt LPG solenoid valve, cone-type strainer, half-union
d. 1-3 gas adjusting block
The copper tubing recommended is 3/8-inch outside diameter, 12 to 14 feet, and
electricians loom about 11 feet to protect the tubing. The LP bottle recommended is
from 6 pounds to 20 pounds capacity depending on the space available to mount the
unit. The tank would be mounted in the trunk or some other rear part of the vehicle.
6.2.3.2 Functional Description
This system is intended to replace the requirement for lead additives in gasoline by
injecting propane (LPG) into the air inlet upon engine load demand. The device does
this by sensing manifold pressure and opening the pressurized LP gas supply to the
air intake stream.
6.2.3.3 Performance Characteristics
No emission data were supplied for the evaluation of this device. One advantage of
this retrofit kit may be that regular gas rather than premium gasoline can be used
with high compression engines. Data verifying this were not provided.
Reduction of pollutants may be indirectly affected by the reduction of lead in the
fuel. Other possible benefits of leadless gasoline would be in the feasibility of
a catalytic muffler installation on the car. Longer spark plug life, longer piston
ring life, and longer muffler system life are some of the additional benefits claimed
by the developer.
6-67
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Figure 6-15. DEVICE 282 LP GAS INJECTION SYSTEM COMPONENTS
ifold to fitting ' A.
run to the air cleaner air
until motor does not ping
A small h,
Another small hose from B'
intake horn. Screw out on "B
on road test.
Figure 6-16. DEVICE 282 LP GAS INJECTION FUNCTIONAL SCHEMATIC
6-68
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With one gallon of propane (4 pounds) the device is claimed by the developer to
operate from 400 to 1,000 miles, depending on the type of load conditions to which a
vehicle is subjected.
6.2.3.4 Reliability
The developer estimated the device has accumulated 600,000 miles installed on
85 vehicles. No mention of device failure was made, nor did the developer estimate
device reliability.
Examination of the device indicated that the vacuum sensitive metering valve and the
vacuum actuated switch have Underwriter Laboratory certification for specific service
applications. To assure that the valve will operate reliably (and safely) specified
maximum input pressure of 250 psi must be observed. The device must be used with a
pressure regulator upstream in the propane delivery line.
The solenoid valve, when actuated at 12 volts dc, requires about 800 milliamperes
current; or about 9.6 watts of power. This constitutes a vacuum switch contact
derating of 50 percent (switch is rated at 12 volts dc, 1.5 amperes) to assure switch
reliability. Solenoid valves of the type used typically exhibit mechanical life
expectancies in excess of one million cycles of operation, provided they are not
overstressed. Electrical power dissipation of only about 10 watts indicates no
electrical overstress to produce premature, thermally induced failures.
In view of the foregoing, and conditioned upon the use of an upstream pressure
regulator (and filter), it is estimated that the device reliability is in excess of
50,000 miles.
6.2.3.5 Maintainability
The developer stated that little or no maintenance is required, unless the LP gas is
unusually dirty, in which case the regulator might need cleaning, perhaps once a
year. The requirement for valve cleaning could be avoided by the use of a filter,
which would be easier to clean or replace. It is estimated that filter maintenance
could be performed once every 12,000 miles in less than 10 minutes, as opposed to
about 45 minutes for cleaning the valve. There should be no repair requirement.
6.2.3.6 Driveability and Safety
This device was not tested during the retrofit study, nor did the developer supply
driveability data. Therefore no evaluation was made as to the effects of this device
on driveability.
No safety hazard has been identified provided an upstream propane pressure regulator
is utilized at the LP gas container. It is required that pressure at the device not
exceed its rating (250 psi maximum, for the device examined) and that the line
pressure be sufficiently low to minimize stored energy release in the event of
rupture.
6.2.3.7 Installation Description
The installation of this device consists in mounting an LPG tank in the trunk of the
car, running a copper tube from the tank to a regulating valve assembly in the
6-69
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engine compartment, mounting the regulating valve assembly, attaching the pitot tube
to the carburetor air intake and connecting this to the regulator valve output, and
connecting a small vacuum hose from the air intake manifold to the body of the
regulating valve assembly. Adjustment of the device consists in setting the output
of the regulating valve assembly so that the engine does not ping on road test.
It is estimated that installation of the complete system would take about 2.5 hours.
Table 6-28 summarizes the installation requirements. Installation could be accom-
plished in a normally equipped repair shop by the average mechanic.
6.2.3.8 Initial and Recurring Costs
Table 6-29 summarizes the installation costs for this device. From the information
available, it is estimated that the installation cost, including material, would be
about $117.50.
Recurring costs would increase mainly on the basis of the additional fuel that has
to be bought. Assuming that an average of one gallon of propane would be used every
500 miles, 100 gallons would be used over the 50,000-mile vehicle service life
assumed for retrofit applications. At 22c per gallon (no State road tax), the addi-
tional fuel cost would be $22.
6.2.3.9 Feasibility Summary
Though no emission data were evaluated, it would appear that this device would have
only a secondary effect on the reduction of emissions, because of the small amount
of propane used over many miles. The device may promote the use of low lead or
unleaded gasoline, thus making the use of a catalytic converter more feasible; how-
ever, no test data indicating whether the device actually accomplishes this were
provided. As a retrofit method for vehicle exhaust emission control, it may be
assumed that the device as presently designed would probably not be applicable.
6-70 .
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Table 6-28. DEVICE 282 LP GAS INJECTION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Mount gas regulator assembly under
hood in engine compartment.
2. Assemble a small hose with the pitot
tube and attach between regulator
output adjustment and air intake
filter.
3. Run a small hose from the regulator
body input to the air intake
manifold.
4. Run hose from regulator input to the
LP tank which may be located in
trunk of car.
5. Install LP tank in trunk: can be
6-20 pound size bottle.
6. Install 45-degree pipe fitting
on tank valve .
7. Wire from vacuum switch to positive
line-engine-run side of ignition
switch, or use special switch in
series if desired.
8. Adjust screw on outlet of regulator
until motor does not ping on road
test .
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill
b. Hand tools
c. Pressure regulator assembly
a. Hand tools
b. Hose
c. Pitot tube
a. Hand tools
b. T-fitting for rubber tubing
a. Hole punches
b. 10-20 feet 3/8-inch copper
tubing
c. Electrician's loom to
protect tubing
d. Hand tools
a. Brackets to hold bottle
b. Hand tools
c. LP tank
a. Hand tools
b. 45-degree pipe fitting
a. Hand tools
b. Vacuum switch
Hand tools
TIME
(MIN)
30
10
30
30
30
5
15
30
Total Time 3 hr
6-71
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Table 6-29. DEVICE 282 LP GAS INJECTION INITIAL AND RECURRING COSTS
ITEM
,
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Pressure regulator
assembly
b. Pipe fittings
c. Pitot tube
d. Vacuum switch
a. 10-20 feet of
3/8- inch tubing
b. Electricians loom
c. LP gas bottle
6-20 pound ca-
pacity
d. Bracket for bottle
50,000-Mile Recurring Cost:
Material
1. Fuel
Labor
T. Filter
Additional propane.
(par. 6.2.3.8)
Clean (par. 6.2.3.5)
LABOR HOURS OR
ITEM QUANTITY
2.5 hr
0.5 hr
Total Initial Cost
1 gal/500 miles
over 50,000 miles =
100 gallons x $0.22/
gal. - $22.00
1/6 hr every
12,000 miles at
$12.50 hour over
50,000 miles
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
45.00
35.00
31.25
6.25
$117.50
$ 22.00
8.33
$30.33
$147.83
6-72
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6.2.4 Device 457; Water Injection
Although no developer was found through the retrofit survey to be using water injec-
tion as a single approach to exhaust emission control, an early HEW/NAPCA report on
the emission reduction benefit of water injection was obtained from EPA files (Refer-
ence 106). Information on the device was too limited to enable a complete system
evaluation of this approach as a retrofit method.
Water injection as early as 1880 and during World War II, in aircraft engines, was
used exclusively to prevent engine knock. It had a secondary advantage on wartime
aircraft in that its cooling effect on the cylinder valves and the pistons prolonged
their service life at high performance levels. The Reference 106 study was performed
to confirm its effect on reducing the NOx emissions in automotive exhaust gases.
This use of water injection was discussed in theory in 1960. Since NOx formation is
basically a function of the peak combustion temperature and fuel-air mixture ratio
(availability of oxygen), any means which affect either of these should have a
corresponding effect on the NOx emissions. Reduction of NOx by use of rich fuel mix-
tures is not as desirable, because hydrocarbons and carbon monoxide tend to increase
with a rich mixture. With water, combustion temperatures are lowered by the heat
used to vaporize, superheat, and finally dissociate the water. The lower combustion
temperature inhibits NOx without significantly affecting the other emissions.
Early tests indicated that at water-to-fuel ratio (on a weight basis) approaching
1:1 j an 80 percent decrease in NOx could be achieved with only small fuel consump-
tion increases and power losses, usually on the order of 10 to 12 percent,(Reference
106) .
6.2.4.1 Physical Description
The water injection equipment was a commercial system sold for detonation control
under a trade name. Water is introduced through a plate installed between the
carburetor and intake manifold. Through incorporation of several toggle valves, the
system could be made to operate whenever it was desired, as contrasted to its former
use only at higher power conditions at wide open throttle. Air was introduced with
the water at the large control valve to help atomize the water on discharge into the
engine.
6.2.4.2 Performance Characteristics
The objective of the Reference 106 project was to confirm previous NOx reduction
findings for roadload conditions and to test an intermediate engine load value
representative of acceleration. Also, the effect of alcohol-water mixture at two
different ratios was studied, to observe the effects'on exhaust emissions. Alcohol
would be added to the water in cold months to keep the water from freezing.
The results of this test program were as follows:
a. For part throttle operation with the engine tested, water injection ratios
of 0.9 Ibs. of water per pound of fuel gave NOx reductions of 75 to 80
percent without appreciable power losses or effects on hydrocarbon or
carbon monoxide emissions.
b. Air-fuel ratios were essentially constant over the range of injection
ratios investigated.
6-73
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c. Exhaust gas temperatures increased with increase in the injection ratio
for part throttle operations; and, conversely, under wide open throttle
conditions, they decreased. Although there was no exact explanation for
this, the leaning effect might account for the temperature increase.
d. Power loss was minimal with water-alcohol injection.
e. As part-throttle operation approached higher loads, the range of injection
ratios becomes less due to their effect on power and hydrocarbon emissions.
Testing was performed on a 1963 Chevrolet with 283-CID engine.
Tests were conducted under the following conditions:
a. Roadloads equivalent to vehicle speeds from 30 to 70 mph, in 10 mph
increments.
b. Intermediate loads (22 inches mercury manifold pressure) for the same
speed range as in Step 1.
c. Wide open throttle at 30 and 50 mph.
For each of these operating conditions, the injection ratios tested ranged from 0.3
to 1.1 Ibs. of water per pound of fuel. Water-alcohol injection, was tested only at
50 mph roadload on two different mixture ratios (80/20 and 60/40 percent respec-
tively) .
Changes in engine torque at constant speed settings were compensated for by throttle
adjustment. Initially, spark timing changes were used to maintain engine performance.
This was discontinued because of its more adverse effect on hydrocarbon emissions.
6.2.4.3 Performance Characteristics
In all cases, the largest reduction in NOx was obtained at the highest injection
ratio (1.1). Through 60 mph, the NOx reduction at this ratio averaged 84.5 percent.
Above 60 mph, the gains in NOx reduction became less because of the limitation on
injection ratios that can be used without adversely affecting power or the other
pollutant emissions. At 70 mph, roadload, the maximum ratio was 0.5. For wide open
throttle operation, the only ratio which gave an NOx reduction was 0.3 and this was
restricted to 30 mph. At 50 mph, wide open throttle, NOx and HC increased by 22 and
32 percent, respectively (Reference 106).
With alcohol-water injection, the 20/80 percent solution decreased NOx concentration
by 80 percent with only a marginal increase of 4 percent in hydrocarbons. The
40/60 percent solution reduced NOx by 84 percent but hydrocarbon concentration
increased to 52 percent. Throttle adjustments to hold power with the alcohol mixtures
were very slight compared to straight water injection. With the latter, increases in
manifold pressure became evident at about a 0.5 injection ratio. At the maximum
ratio, the manifold pressure usually increased between 1.5 and 2.0 inches mercury
above the baseline setting at any test condition (Reference 106).
6.2.4.4 Feasibility Summary
The Reference 106 report concluded that:
a. An injection system should be tested on the road and/or under cycling condi-
tions on the chassis dynamometer for emission evaluation and driveability.
6-74
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b. The continuous effects of water injection on engine durability should be
evaluated.
c. The design and economic feasibility of incorporating water on a passenger
car should be determined.
d. The effect water injection on specific groups of hydrocarbon under similar
test conditions should be determined.
It appears to be generally accepted and reasonably substantiated that water injection
modifies the combustion process such that the peak temperatures are reduced in the
combustion process, thereby reducing the formation of NOx emissions. The peak
temperature is reduced because of the dilytent effect of water on the combustion
process in that the water must be heated to the temperature of combustion gases, but
does not undergo chemical reaction or contribute to energy release.
Intake-manifold water injection has a further advantage in that its evaporation cools
the gases in the induction system. This increased gas density results in higher
mass flows through the engine and thereby provides higher maximum power levels. A
disadvantage of water injection is the possible formation of sludge in the engine
crankcase and acceleration of engine wear. Also at high injection ratios, drive-
ability is unacceptable due to excessive power loss.
In summary, it may be concluded that water injection would offer only limited retro-
fit control applicability, because it is mainly an NOx control.
6-75
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6.3 FUEL CONDITIONER - RETROFIT SUBTYPE 1.4.3
This category of retrofit device attempts to modify the fuel for improved combustion
by means of electrical treatment. Two devices were found in this category through
the retrofit method survey.
6.3.1 Device 36; Fuel Conditioning by Exposure to Electromagnetic Field
Contact with the developer of this device was not completed during the retrofit study
due to insufficient address information; however, limited evaluation of the device's
emission reduction effectiveness was possible on the basis of a HEW/NAPCA test
report (Reference 107).
6.3.1.1 Physical Description
This device installs in the fuel line between the fuel pump and carburetor and sub-
jects the fuel to a low intensity magnetic field from a series of permanent magnets
and a 12-volt battery.
6.3.1.2 Functional Description
The developer reported to HEW/NAPCA that "the low intensity magnetic/electrostatic
field orients disordered molecular arrays to improve vaporization and atomization
characteristics of the fuel." The developer stated that his testing "indicated that
the effects were more closely related to the pre-reaction phenomena, including
pyrolysis of fuel, than the terminal phase of the combustion process." The net ef-
fect is claimed to be a change in combustion chamber deposits, less smokey exhaust,
reduced engine knock with lower grade fuels, and reduced emissions.
6.3.1.3 Performance Characteristics
Emission tests conducted by HEW/NAPCA are summarized in Table 6-30. A single
vehicle was driven 2,932 miles without the device to establish an emission baseline
and 2,735 miles with the device to determine its emission reduction effectiveness.
At approximately 500-mile intervals, hot start emission tests (1970 Federal pro-
cedure - CVS) were conducted on the test vehicle.
6.3.1.4 Feasibility Summary
The HEW/NAPCA report concluded that, based on the test program, the device did not
appear to affect exhaust emissions reductions.
6-76
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Table 6-30. DEVICE 36 FUEL CONDITIONING BY EXPOSURE TO ELECTROMAGNETIC FIELD
EMISSION TEST RESULTS (REFERENCE 107) (1)
VEHICLE
CONFIGURATION
POLLUTANT (GM/MI)
HC
CO
Without Device (2)
With Device (3)
7.12
8.02
48.8
50.0
Not
Measured
Percent Reduction
-12.5
-0.4
(1) Average of results from 1 baseline and 11 retrofit tests using
1970 Federal Test Procedure (Reference 15)
(2) Average of 13 tests during 2,932 miles
(3) Average of 11 tests during 2,735 miles
6-77
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6.3.2 Device 279; Fuel Activator
This device is patented and is currently marketed as an "activator" for either
gasoline or diesel fuels. The device operates off electric power from the battery.
The developer stated that the device "distorts the molecular structure of the ele-
ments present in hydrocarbon fuels and utilizes electric current to fix this distor-
tion." The developer claims that the automatic activation of fuel by this device
(1) saves as much as 15 percent of actual fuel costs, (2) eliminates air pollution
by as much as 80 percent, and (3) reduces maintenance costs 25 percent.
6.3.2.1 Physical Description
A schematic of this device is shown in Figure 6-17. The device is a steel tube
approximately 2 inches in diameter and 8 inches long with threaded closures
on both ends. Two manganese steel electrodes enter the end caps through
insulators at opposed ends. The photographed part shows two spark plugs
mounted on one end. According to the drawing and developer supplied informa-
tion, three magnets in the form of perforated desks are mounted inside the tube.
The entire inside surface of the tube and closures is said to be coated with mer-
cury. Two nipples are provided at opposite end closures for connection of fuel
inlet and discharge lines.
FUEL LINE FROM
FUEL PUMP
FUEL LINE TO
CARB. OR INJECTORS
CLAMP
TO BODY
WIRE TO POS.
TERMINAL OF
BATTERY
Pat. No. 814 269
International Classification No. ClOg
WIRE TO GROUND
Figure 6-17. DEVICE 279 FUEL CONDITIONER FUNCTIONAL SCHEMATIC (DEVELOPER DATA)
6.3.2.2 Functional Description
The developer's patent disclosure claim is that the device is
"(1) A method for increasing the combustion efficiency of liquid fuel
consisting of subjecting the fuel simultaneously to a magnetic
field produced between two adjacent like poles and to an electro-
static field a short period of time prior to its combustion.
6-78
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"(2) An apparatus to increase the combustion efficiency of liquid fuel,
comprising a closed metal receptacle, openings in the opposite
ends of said receptacle for inlet and outlet of the fuel, at least
two permanent magnets with their like poles adjacent placed in the
path of the fuel, two electrodes placed in the path of the fuel
and a film of mercury amalgamated with the interior surface of
said receptacle.
"(3) An apparatus as in Claim (2) in which said magnets are centrally
perforated discs, their faces being the poles of said magnets.
"(4) An apparatus as in Claim (2) wherein said electrodes are coaxially
mounted manganese steel rods."
6.3.2.3 Performance Characteristics
Table 6-31 presents a summary of performance information supplied by the developer
from tests conducted on a 1969 Chevrolet by Stevens Institute of Technology in
April 1971. The small decreases in HC and NOx emissions indicated by these hot
start tests are not considered significant. The CO emission reduction, though
relatively more effective, would not alone justify use of the device for emission
control purposes.
Table 6-31. DEVICE 279 FUEL CONDITIONER EMISSION TEST RESULTS
REPORTED BY DEVELOPER (1)
VEHICLE
CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT
HC , ppm
147
142
3.4
CO, %
0.53
0.40
24.5
NOX, ppm
1,508
1,442
4.3
(1) Results obtained by Stevens Institute of Technology using 1970
Federal Test Procedure (Reference 15) , one cycle 6 and 7 hot test
without and one with the device installed.
(2) 1969 Chevrolet Kingswood equipped with 372-CID V-8 engine with two-
barrel carburetor and automatic transmission. Odometer reading was
31,539 miles at beginning of the tests.
6.3.2.4 Reliability
Examination of the device's construction indicates that it should remain structurally
and functionally intact for at least 50,000 miles.
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6.3.2.5 Maintainability
No maintenance requirement is anticipated other than replacement of electrical
wiring if necessary.
6.3.2.6 Driveability and Safety
Since the device was not tested in the retrofit study and the developer supplied no
driveability data, the effects of this device on driveability were not evaluated.
Internal construction of the device, and materials used are not known. It might be
possible with applied voltage across the internal insulation to cause ionization
resulting in a low resistance path between the electrodes. This might cause a
potential fire hazard in the fuel line.
6.3.2.7 Installation Description
Installation of this device consists in mounting the fuel activator in the engine
compartment close to the fuel pump, connecting the activator into the fuel line
between the fuel pump and the carburetor, and connecting the device's electrical
wires to the battery and to ground.
The developer estimated that one-half hour of labor would be required to install the
device. Table 6-32 summarizes the installation requirements. Installation could
be accomplished in a normally equipped repair shop by the average mechanic.
Table 6-32. DEVICE 279 FUEL CONDITIONER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1.
2.
3.
A.
Install Fuel Activator in engine
compartment close to fuel pump
using clamp to body and sheet
metal screws.
Cut fuel line between fuel pump
and carburetor and insert Fuel
Activator into fuel line.
Connect one wire from unit to posi-
tive terminal of battery.
Connect wire from unit to ground .
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill sheet
b. Metal screws
c. Fuel activator
Hand tools, clamps
Wire
Wire
TIME
(WIN.)
20
5
3
2
Total Time 0.5 hr.
6-80
-------
6.3.2.8 Initial and Recurring Costs
The developer estimated that the purchase price of this device would be $5.00.
Table 6-33 summarizes the installation costs. It is estimated that the cost of
installing this device including material, would be $16.25. No recurring costs were
identifiable.
6.3.2.9 Feasibility Summary
This device appears to be infeasible as a retrofit emission control device. The
test data provided by the developer, though not based on a wide test sample, indi-
cates nq significant reduction? in HC or NOx emissions, and only a nominal reduction
in CO.
Table 6^33. DEVICE 279 INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and
adjust
DESCRIPTION
Fuel Activator^
a. Sheet meta],
screws
b. Clamps
c. Electric wire
Electric Dr^ll
LABOR HOURS OR
ITEM QUANTITY
0.5
COST
(DOLLARS)
10.00
(Included in
above)
6.25
Total Initial Cost $16-25
Recurring Cost: None
TOTAL COSTS $16.25
6-81
-------
7 - BLOWBY
CONTROL SYSTEMS
-------
SECTION 7
GROUP 2 RETROFIT METHOD DESCRIPTIONS
CRANKCASE EMISSION CONTROL SYSTEMS
Crankcase emission control systems normally provide a means of directing crankcase
blowby gases and ventilation air to the intake manifold for induction along with
the carburetor air-fuel mixture. These systems are commonly referred to as positive
crankcase ventilation (PCV) devices. The method of controlling the amount of blowby
gases is the key to each of the approaches in this type of device. A second control
provided by some devices of this type is to filter impurities from the blowby gases,
to prevent the degrading effect they might have on the fuel induction system and
combustion. In addition, some of these devices appear to decrease exhaust emissions.
All emission test results reported for the devices were exhaust emissions data.
None of these devices was tested in the retrofit program for either exhaust emissions
or blowby control effectiveness.
These devices normally should control the crankcase blowby flow so that air-fuel mix-
tures are not upset. Normally, the blowby gas is unburned air-fuel mixture that
leaks past the piston rings during compression and combustion strokes. When this
blowby is recirculated to the intake manifold, it does not change the air-fuel ratio
of the incoming mixture because the two mixtures are of the same air-fuel ratio.
However, the crankcase ventilation air does slightly lean the air-fuel mixture.
On pre-1968 vehicles which were factory equipped with PCV systems, use of the air-
bleed retrofit systems may cause excessively lean air-fuel ratios which might cause
"lean misfire." This could result from a combination of high ventilation airflow
rates through the PCV valve and the additional air provided by an air-bleed system
installed between the PCV valve and the intake manifold. High crankcase ventilation
air flow rates are more likely to occur on newer PCV-equipped vehicles, which have
low blowby flow rates. As a vehicle accumulates mileage, the blowby flow rate gen-
erally increases and the amount of ventilation airflow decreases. Thus, the possi-
bility of excessive air ventilation decreases with vehicle age. However, when PCV
is used in combination with the air-bleed device, the air-bleed may reduce the
PCV outlet absolute pressure, and cause the PCV valve airflow rate to increase at
a given manifold vacuum. For example, at low speeds and at 14 inches of mercury
manifold vacuum, the PCV valve outlet vacuum and the manifold vacuum would be about
the same without the air-bleed retrofit device installed. The addition of an air-
bleed device may lower the PCV outlet vacuum to 12 inches of mercury, resulting in
a premature increase of PCV airflow which could overlean the air-fuel mixture.
In the retrofit study, there were five PCV systems found to be available for retro-
fit use. These systems are listed in Table 7-1. As shown, one of these systems is
of the combination air-bleed-blowby type.
7-1
-------
Table 7-1. GROUP 2 CRANKCASE EMISSION CONTROL SYSTEMS
CLOSED SYSTEM - TYPE 2.1
DEVICE NO.
24 (1)
170 (2)
315
NOMENCLATURE
Heavy Duty Positive Crankcase Control Valve with Air Bleed
Closed Blowby Control System
Closed Blowby Control System
OPEN SYSTEM - TYPE 2.2
160 (2)
427
Closed or Open Blowby Control System with Filter
Closed or Open Blowby Control System with Filter
(1) Previously tested by EPA
(2) Accredited for use in California.
7-2
-------
7.1 CLOSED SYSTEM - RETROFIT TYPE 2.1
Crankcase emission control systems are classified as open or closed. In open sys-
tems, ventilation air is taken directly from the engine compartment through the oil
filler cap and circulated through the crankcase, mixing with blowby gases, and cir-
culated to the intake manifold. Closed systems are similar to open systems except
that they receive ventilation air through the carburetor air cleaner. One of the
devices described in this section is classified as a "sealed" system. In this sys-
tem there is no ventilation air circulated through the crankcase. Only blowby gases
are inducted into the intake manifold through the flow control system.
7.1.1 Device 24; Heavy Duty Positive Crankcase Control Valve with Air Bleed
This device is a combination air bleed and blowby recirculation system. The device
is in production and, according to information from the developer, thousands have
been sold. The system description is based on developer data and an EPA exhaust
emissions test report. Because of the air-bleed capability, the device might have
some effectiveness in controlling exhaust as well as blowby emissions.
7.1.1.1 Physical Description
The overall system consists of a variable orifice (or jet) valve (called a power
booster by the developer) that connects to the intake manifold, and a blowby gas oil
separator and filter unit that installs in the blowby line between the variable
valve and the crankcase. The valve components and the separator unit are shown in
Figure 7-1.
7.1.1.2 Functional Description
The variable valve contains a jet which proportions the amount of air added accord-
ing to intake manifold vacuum. This valve replaces the conventional PCV valve.
The principal component is a piston that is controlled by manifold vacuum. The jet
permits additional air to be drawn through the crankcase by the vacuum. This is
claimed to give effective pollution control, proper fuel mixture and full engine
power; by adding air to the blowby mixture, unburned fuel in the blowby is claimed
to be burned more efficiently to increase fuel mileage.
The filter (only) used in conjunction with the valve was approved by California in
1966. Basically, the filter is dual chambered with an integral series of baffles
to separate oil from blowby fumes, and to filter sludge-forming hydrocarbons. The
oil separated from the blowby fumes is gravity fed back to the crankcase. Since no
oil is burned with the exhaust fumes, spark plugs are said to stay cleaner and last
longer. Hydrocarbons are removed from the blowby by condensing them and depositing
them in the sludge trap chamber. As a result, the filter is said to increase the
life of exhaust and PCV parts and retard sludge buildup in the engine.
7.1.1.3 Performance Characteristics
The results of EPA exhaust emission tests on this device are summarized in Table 7-2.
The EPA report concluded that the exhaust emission reductions with the device were
marginal, as was any fuel savings.
7-3
-------
OIL DRAIN
TO ENGINE
OIL/PARTICLE
SEPARATOR
4 PISTON RINGS
mm®
TO MANIFOLD
HEAVY" "DUTY
VARlABLg JiT .P£V,
VALVE
^OPENING TO MANIFOLD OR
"ADAPTER
TO VALVE LIFE EXTENDER
Figure 7-1. DEVICE 24 SYSTEM COMPONENTS (DEVELOPER DRAWING)
Table 7-2. DEVICE 24 HEAVY DUTY POSITIVE CRANKCASE CONTROL VALVE
WITH AIR BLEED EXHAUST EMISSION TEST RESULTS
REPORTED BY EPA (REFERENCE 95) (1)
VEHICLE CONFIGURATION (2)
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC
4.63
4.45
3.9
CO
50.36
44.03
12.6
NOx
6.59
6.10
7.4
(1) Average of 6 tests without device and 5 with device for CO and HC, and
three without plus four with for NOx. All tests were performed in
accordance with the 1972 Federal Test Procedure (Reference 3).
(2) 1970 Chevrolet with 350-CID engine and automatic transmission.
7-4
-------
7.1.1.4 Reliability
Use of the device on thousands of vehicles would indicate that it has adequate ser-
vice life reliability. The developer (who also manufactures the device) warrants
the device for 100,000 miles without defects or partial failures. This would appear
to be a reasonable MMBTF, provided that the device is maintained as specified by the
developer.
7.1.1.5 Maintainability
According to the developer, the device should be removed, disassembled and cleaned
with solvent every 25,000 miles (MMBM).
Both the filter and the variable orifice valve may be cleaned in carburetor cleaner
or any solvent. It is not necessary to remove the piston rings when cleaning.
It is estimated that this cleaning operation would take about 15 minutes (0.25 hr
MTTM).
7.1.1.6 Driveability and Safety
The device apparently has no driveability or safety problems. A major installer of
the device reported that fuel economy on his own cars increased from two to five
miles per gallon with greater engine power and smoother performance. His customers
had the same experience with the system.
7.1.1.7 Installation Description
According to the developer, there is no restriction as to where to install the valve.
It may be mounted wherever space will allow, as it can be operated in any position.
The filter unit, however, must always be ahead of the valve. The vacuum passage to
the carburetor must be 5/16 inch or larger. In some cases, it is necessary to remove
the carburetor and run a 5/16-inch reamer through steel tubing into the aluminum
housing and enlarge the hole from the bottom to meet the reamed hole. Average in-
stallation time, including adjustment of the carburetor air-fuel ratio, would be
about 0.75 hr. Installation could be performed in the average repair shop with
mechanic skill level.
7.1.1.8 Initial and Recurring Costs
Initial purchase and installation costs would be about $34. Unit costs are as shown
in Table 7-3.
7.1.1.9 Feasibility Summary
Based on EPA test results, this device appears to provide marginal effectiveness for
the reduction of exhaust gas emissions. The principal pollutant controlled appears
to be CO. This conclusion is based on limited test data, and does not apply to the
device's use to control blowby gases from being emitted to the atmosphere from the
crankcase. As a blowby control, the device would appear to be both technically and
economically feasible. Use with other air-bleed type systems would possibly require
testing to establish compatibility.
7-5
-------
Table 7-3. DEVICE 24 HEAVY DUTY POSITIVE CRANKCASE VENTILATION
WITH AIR BLEED INITIAL AND RECURRING COSTS
ITEM
Initial Costs:
Material
1. PCV Valve
2. Life Extender
3. Hoses
Labor
1. Installation
DESCRIPTION
Paragraph 7.1.1.7
LABOR HOURS OR
ITEM QUANTITY
0.75 hr (1)
Total Initial Cost
50,000-Mile
Recurring Costs:
Material
1. Fuel (2)
Labor
1. Cleaning
Clean valve and
filter every 25,000
miles
0.25 hr @ $12.50
per hr x 2
cleanings
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS )
14.95
7.95
1.50
9.38
33.78
6.25
6.25
40.03
(1) Replacement time for the PCV valve only is estimated to be 0.2 hour.
(2) Fuel economy reported, but no specific data provided.
-------
7.1.2 Device 170; Closed Blowby Control System
This device provides modifications which seal the crankcase from the atmosphere and
provide controlled recirculation of crankcase blpwby gases to the intake manifold
and carburetor air cleaner. The basic purpose of this device is to control HC
blowby emissions and minimize crankcase contamination. Recirculation of blowby
gases to the induction system is accomplished without mixing them with air. Recir-
culation of additional air, as with a conventionally ventilated crankcase, is
eliminated.
This device was certified as a crankcase emission control device by the California Air
Resources Board in September 1965. According to the developer, approximately 10,000
units were manufactured before production was terminated. Several thousand units were
marketed. California accreditation was transferred to a new legal owner in December
1970. Manufacturing and marketing plans are being implemented by the new owner.
A limited amount of test data indicates this device may be effective in reducing HC
and NOx exhaust emissions, in addition to controlling crankcase blowby.
7.1.2.1 Physical Description
Components of this system are shown in the simplified drawing of Figure 7-2. The
principal component is the combination pressure-relief, adjustable-flow valve shown
in Figure 7-3.
The system shown in Figure 7-2 includes the following components:
a. A combination relief and adjustable flow valve (B) which regulates the re-
circulation of crankcase gases to the intake manifold and carburetor air
cleaner.
b. A 5/8-inch inside diameter (I.D.) hose connected between the crankcase
outlet (A) and the combination valve (B).
c. A 3/8-inch I.D. hose connected between the intake manifold (D) and adjust-
able flow valve outlet port (C) of the combination valve (B).
d. A 5/8-inch I.D. hose connected between the relief valve outlet port (E)
and the carburetor air cleaner (F).
e. Crankcase sealants consisting of a rubber plug for the road draft tube and
a rubber sealant for the dipstick cup.
The three hoses used in this system are standard neoprene rubber automotive hose.
Sealant for the dipstick is obtained by potting the dipstick cap with room temper-
ature vulcanizing rubber.
The principal component of the system is the combination adjustable flow and relief
valve shown in Figure 7-3. This assembly consists of a molded plastic tee having
four parts. Attached to one part is a plastic 5/8-inch inside diameter hose nipple
which accepts the inlet hose from the crankcase.
7-7
-------
VALVE COMBO
FACTORY ASSEMBLED
AND INSPECTED. INDI-
VIDUALLY PACKED
CLIPS-REMOVE TO RELEASE CONNECTIONS
2 J x—% ID. HOSE
^ TO INTAKE MANIFOLD
ADJUSTABLE VALVE|(WITH
BACKFIRE FLAME ARRESTER)
Method of adjustment shown
below
PLUG-
REMOVE TO
INSERT VACUUM
GAUGE
13/16-HEX (2 PLACES) V 3/16" HOLE-4
(MAXIMUM
FLOW SETTING)
TO INTAKE
(MINIMUM MANIFOLD
FLOW SETTING) VACUUM
CRANKCASE
EMISSION FLOW
•1/16" HOLE
METERING ORIFICES - HOLE SIZES
Figure 7-2. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM (DEVELOPER DRAWING)
VACUUM GAUGE
• NEGATIVE PRESSURE FLOW
(BLOWBY GASES) 0)LF|LLTUBE
A - CRANKCASE OUTLET
B - VALVE COMBO
C - ADJUSTABLE VALVE
D - VACUUM SOURCE
E - RELIEF VALVE
f - AIR CLEANER ATTACHMENT
G - VACUUM GAUGE INSERTION
DIPSTICK (SEALING)
ROAD DRAFT TUBE (PLUG)
Figure 7-3. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM ADJUSTABLE BLOWBY FLOW
AND PRESSURE RELIEF VALVE (DEVELOPER DRAWING)
7-8
-------
Attached to a second port is a metal adjustable valve assembly with a 3/8-inch
inside diameter hose nipple which connects to the hose leading to the intake mani-
fold. The valve assembly includes a ball type check valve which prevents backfire
from the intake manifold to the crankcase.
The adjustable valve is set at the time of installation to meter desired blowby
flow and may be reset at maintenance intervals to reestablish flow regulation if
required.
The third port is to a ball type relief and check valve. This valve is designed so
that it only opens to flow crankcase vapor when the crankcase pressurizes to
inch water above local atmospheric pressure. The valve will also check close to
prevent any flow reversal into the intake manifold.
The fourth port has a removable plug which is removed for installation of a vacuum
gage. The vacuum gage is used to set the adjustable metering valve during instal-
lation and maintenance.
The components described herein have been mass produced. Tooling exists for plastic
molded and die cast parts.
7.1.2.2 Functional Description
Figure 7-2 indicates the functional concept of this device. At time of installation
all openings leading to the crankcase are sealed or plugged to make the device a
closed system. Outside air, dirt, and moisture cannot get in through the normal
ventilation paths. Blowby gases are returned to the intake manifold and on to the
combustion chambers.
The engine intake manifold vacuum is utilized as a motive force to circulate the
flow of emissions through the hose network and to create a moderate vacuum in the
crankcase at warm idle condition. A crankcase vacuum of 4 to 5 inches of mercury
at idle conditions is established by adjusting the metering valve (B in Figure 7-2).
The adjustment is made using a special valve adjust tool provided by the developer.
The closed system operates as follows (Figure 7-2):
a. Primary flow blowby gases are withdrawn from crankcase at outlet (A). They
are metered through variable orifices in the adjustable valve (C), then flow
into the intake manifold through a fitting located at or near base of car-
buretor at (D). Flow is active in this part of the system during all modes
of operation.
b. Secondary Flow - When intake manifold vacuum is inadequate to handle all
blowby gases in the primary flow circuit, crankcase will start to pressur-
ize. The relief valve at (E) responds and opens at about 0.5-inch water crank-
case pressure and allows excess blowby to pass into carburetor inlet through a
fitting on the air cleaner (F).
c. Backfire Condition - Ball-check flame, Arresters are located at (C) and
(E) to prevent backfire from entering crankcase at all times.
7-9
-------
7.1.2.3 Performance Characteristics
Presented in Table 7-2 is a summary of exhaust emission performance data supplied by
the developer. The emission data shown consist of a single California seven-mode
hot start test conducted on a 1956 Chevrolet with and without the device. This
single test indicates that the device may be effective in reducing HC and NOx ex-
haust emissions. Examination of the developer's report indicates that exhaust base-
line data were obtained with "device disconnected."
Table 7-4. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM EXHAUST EMISSION
TEST RESULTS (DEVELOPER DATA) (1)
VEHICLE CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT (GM/MI)
HC (PPM)
440
395
10
CO (%)
3.5
4.4
-31
NOx (PPM)
1,520
810
47
(1) Results of one 7-mode hot start cycle with and without device installed
on a 1956 Chevrolet, using the California 7-cycle, 7-mode test proce-
dure (Reference 115). The vehicle had a 265-CID engine with 4-barrel
carburetor and automatic transmission. Odometer reading was 82,677
miles at start of testing.
7.1.2.4 Reliability
The developer estimated a device reliability of 100,000 mean-miles-before-total-
failure (MMBTF). The estimate is based upon an estimated 7,000 vehicle installa-
tions with no report of failure. The device is accredited by the California Air
Resources Board. Since the device consists functionally of two simple free-ball
valves and a metering orifice, the manufacturer's reliability estimate appears
reasonable.
7.1.2.5 Maintainability
The developer estimated the need for 15 minutes of maintenance at 12,000-mile inter-
vals. This would consist in cleaning the device and resetting the orifice, if nec-
essary. Following are the developer's detailed maintenance requirements:
Relief Valve
1. Remove from hose network and disassemble by withdrawing clip.
2. Submerge parts in solvent or kerosene. Clean all surfaces with stiff
brush. Rinse with clean solution and dry using air gun.
7-10
-------
3. Inspect nylon ball and 0-rings, Replace if required.
4. Assemble valve and re-install to system.
Note: Replacement 0-rings and nylon balls are supplied in the inspection
and maintenance kit.
Hoses and Hardware .
All hose interiors should be flushed with solvent or kerosene. Force dry
using air gun.
All other hardware components to be cleaned by conventional methods.
Adjustable Valve
1. Remove valve from hose network and disassemble, using 13/16" hex wrench.
Caution - hold hand in position to catch nylpn ball if it drops out
when the parts separate.
2. Submerge parts in solvent or kerosene to soften hard deposits and
varnish.
3. Probe all hole passages with proper size drills. To clean orifices,
use valve adjust tool, Rotate orifices to align holes for cleaning.
Drills should be rotated with hand pressure only..
4. Rinse all parts in clean solution and dry with air gun.
5. Inspect nylon ball. If badly pitted or worn, it should be replaced.
0-ring seals distorted or damaged also should be replaced.
6. Assemble the valve and re-ins.tgll to original location in the system.
7. Reset orifices for idle-vacuum per inspection procedure.
Inspection Procedure
1. Start engine and establish warm-idle condition.
2. Insert vacuum gauge into system to read crankcase idle-vacuum.
3. Read idle-vacuum. If gauge reads -4 to -5, system is O.K. If reading
is below -4, restore the idle vacuum by increasing"flow through the
adjustable valve.' (Insert tool as shown in Figure 7-4 and rotate
toward maximum setting.) .
It is estimated that the indicated maintenance could be accomplished in 15 minutes,
exclusive of engine warmup time after the device has been cleaned. No repair re-
quirement is anticipated.
7-11
-------
MINIMUM FLOW
SETTING
Figure 7-4. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM ADJUSTMENT PROCEDURE
7.1.2.6 Driveability and Safety
This device was not tested during the retrofit study and the developer supplied no
driveability data. Although no evaluation was possible as to the effects of this
device on driveability, the fact that it has been used on 7,000 vehicles would indi-
cate that it does not affect driveability adversely.
7.1.2.7 Installation Description
This device installation consists in removing the presently installed PCV valve,
installing a special valve in the engine compartment, connecting hoses from the
valve to the crankcase, air cleaner, and intake manifold, and sealing all other out-
lets to the crankcase. Adjustment of the device consists in setting the valve so
that crankcase vacuum reads 5 inches of mercury with the engine at idle. Adjustment
of the engine requires adjusting the carburetor idle mixture as necessary to restore
normal idle.
Table 7-5 contains a more detailed description of the installation procedure and
identifies tools and special equipment required. Figure 7-4 illustrates adjustment
of the valve and Figure 7-5 shows a typical installation. Installation can be
accomplished in a normally equipped repair shop with average skills.
VALVE COMBO attached directly to engine
accessory to utilize shorter length hoses.
VALVE COMBO attached to structure of en
gine compartment for ease of installation.
Figure 7-5. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM INSTALLATION (DEVELOPER PHOTOS)
7-12
-------
Table 7-5. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1. Inspect engine for leakage to insure that when
system is installed the crankcase can maintain
a vacuum
2. Install mounting bracket in engine compartment
3. Attach valve combination to mounting bracket
4. Remove PCV valve and hose
5. Install hose hookup to rocker arm cover
6. Install hose hookup to air cleaner
7. Connect hose from rocker arm cover to valve
combination, from valve to intake manifold,
and from valve to air cleaner
8. Plug and seal all other outlets to crankcase
9. Start engine and adjust valve until vacuum
gage installed at valve reads 5 inches of Hg
10. Make adjustments as necessary to carburetor to
restore normal idle
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Mounting bracket
a. Hand tools
b. Valve combination
Hand tools
a. Hand tools
b. Hose hookup
a. Hand tools
b. Hose hookup
Hose
a. Hand tools
b. Plugs and sealant
Vacuum gage
Tachometer
Total Time
TIME
(MIN. )
15
5
5
5
15
15
10
20
5
10
1.75 hr
7.1.2.8 Initial and Recurring Costs
The developer estimated that the cost of the device should be $12 to $17. Table 7-6
summarizes the installation costs for this device. From the information available,
it is estimated that the cost for installing this device, including material, would
be $33.87 to $38.87.
7.1.2.9 Feasibility Summary
Limited test data provided by the developer indicate that this device might be ef-
fective in reducing HC and NOx exhaust emissions, with a possible penalty in in-
creased CO emissions. Additional tests would be required to establish the statistical
significance of this exhaust emission reduction effectiveness. The device is well
designed for production as an accredited retrofit crankcase control device in Calif-
ornia, and several thousand units have been manufactured and sold in California for
this application.
7-13
-------
Table 7-6. DEVICE 170 CLOSED BLOWBY CONTROL SYSTEM INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labpr
1. Installation
2. Test and adjust
DESCRIPTION
a. Valve mounting
bracket
b. Valve combination
a. Hose hookup
b. Hose
c. Plugs and sealant
Table 7-5
Table 7-5
LABOR HOURS OR
ITEM QUANTITY
1.5 hr
0.25 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Labor
1. Inspect, clean,
and adjust
Paragraph 7.1.2.5
0.25 hr every 12,000
miles @ $12.50 per hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
12.00-17.00
(Included
in above)
18.75
3.12
33.87-38.87
12.50
12.50
51.37
7-14
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7.1.3 Device 315; Closed Blowby Control System
Categorized as a Type 2.1 closed crankcase emission control retrofit system, the
device described below is actually (as described by its developer) a sealed system.
That is, there is no opening for ventilation airflow and flow of blowby gases and
crankcase fumes other than the controlled passage to the intake manifold. However,
a relief or safety valve may be installed in the crankcase. The device includes
provisions designed to facilitate a more thorough mixing of fuel and air (presum-
ably) along with the crankcase emissions.
The principal feature of Device 315 is its blowby flow control method, a throttle
linkage operated flow control valve. Auxiliary to the main device, and included in
the installation, is the fuel "vaporizer," intended to cause a "more thorough mixing
of the fuel, air," and the crankcase emissions.
This device is in the prototype development stage. According to the developer, 16
such devices have been manufactured and installed on 16 vehicles which have accumu-
lated 440,000 miles of operation. Data regarding the tests performed on two of
these vehicles have been furnished by the developer.
7.1.3.1 Physical Description
The principal component of Device 315 is the engine vent valve assembly and its
linkage to the throttle control arm. Figure 7-6 illustrates the installation of
this valve on a two-barrel carburetor (replacing the PCV hose connection). As may
be noted in the figure, this prototype kit included a valve assembly (1) with a
carburetor adapter fitting (2) at its outlet and a hose fitting (3) at the inlet;
a valve body support bracket (4) bolted to the carburetpr body; and a throttle
linkage adapter (5) fastened to the throttle arm with a connecting rod (6) to the
valve slide.
An auxiliary component, also seen in Figure 7-6, is the vaporizer assembly which
includes an adapter plate (7) with two free spinning turbine wheels (8).
Not shown are the hose and fittings connecting the valve.inlet to the crankcase
(i.e., rocker arm cover), necessary fittings or replacement parts to disconnect
and seal crankcase vent openings (i.e., oil filler cap) and carburetor air cleaner
hose connection; and a crankcase relief valve assembly (if required for safety
purposes).
The valve body is 1-1/4 inch in diameter by 3 inches; the valve slide is 1/2-inch
square by 3 inches. The overall length of the installation is 7 inches from inlet
fitting to outlet fitting.
7.1.3.2 Functional Description
This device connects the crankcase (or valve cover) to the downstream side of the
carburetor throttle blades to draw crankcase emissions into the intake manifold in
a manner similar to the conventional PCV valve and hose. However, for this device,
valve operation is by direct linkage to the throttle control. The flow control
valve, as shown in Figure 7-7, varies in orifice area as the valve is operated, to
provide minimum flow at idle, and increases as the throttle is opened. Figure 7-7
depicts a rotating type control valve design. The prototype device in Figure 7-6
7-15
-------
BBOM
Figure 7-6. DEVICE 315 CLOSED BLOWBY CONTROL SYSTEM INSTALLED ON CARBURETOR
VENT VALVE ORIFICES
ROTARY TYPE
886
Figure 7-7. DEVICE 315 CLOSED BLOWBY CONTROL SYSTEM VENT VALVE CONFIGURATION
(BASED ON DEVELOPER DRAWINGS)
7-16
-------
applies a slide valve mechanism as depicted in Figure 7-8. The developer states
that the "sliding motion (whether rotary or linear) coupled with orifice shape
promotes a self-cleaning action, minimizing the maintenance problem." He further
points out that the valve inhibits backfire (if it occurs) from reaching the
crankcase.
I .."
o
[jn
886
Figure 7-8. DEVICE 315 SLIDE MECHANISM (BASED ON DEVELOPER DRAWINGS)
The vaporizer element of this device (shown in Figure 7-6) is described by the de-
veloper as follows:
"A bladed wheel, fan, turbine or the like is mounted in or below the down-
draft side of the carburetor and has an even number of equidistantly spaced
blades, alternate ones of which are tilted at a relatively large angle to
the axis of the turbine to cause rotation of the turbine by the fuel intake
suction while the remaining blades, each of which is positioned between two
propulsion blades, have any angle of tilt with respect to the tilt angle of
the propulsion blades such that said remaining blades resist and slow down
the speed of rotation of the turbine while causing more thorough mixing of
the fuel and air mixture, consequent to increased vaporization of the fuel."
7.1.3.3 Performance Characteristics
Table 7-7 summarizes the exhaust emission test results reported for this device
compared to the baseline vehicle without the device installed. These results in-
dicate that the device may have some effectiveness for control of exhaust HC and
CO. Further testing would be required, however, to substantiate the statistical
significance of this effectiveness.
7.1.3.4 Reliability
Examination of the carburetor modifications indicated that a fully engineered system
would have a potential reliability in excess of 50,000 mean-miles-before-total-
failure. Of particular interest is the selection of material for corrosion resist-
ance in the gas flow circuit and valve. Additional consideration should be given
the structural integrity of the free-spinning turbine vaporizer to preclude fatigue
failures.
7-17
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Table 7-7. DEVICE 315 CLOSED BLOWBY CONTROL SYSTEM EXHAUST EMISSION TEST RESULTS
REPORTED BY DEVELOPER (1)
VEHICLE CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT
HC (PPM)
201
144
28.3
CO (%)
82
59
28.0
NOx (PPM)
(2)
(1) Results obtained from one 7-cycle, 7-mode test with and without device
installed on a 1969 Ford, with 390-CID engine and automatic transmission.
(2) Not reported.
7.1.3.5 Maintainability
It is anticipated that maintenance requirements for a fully engineered device would
be limited to cleaning and adjusting at such times as the carburetor would be nor-
mally cleaned and/or adjusted. An MMBM of 25,000 miles and MTTM of 0.75 hour are
estimated.
7.1.3.6 Driveability and Safety
In the device configuration examined, corrosion of the blowby control valve could
result, ultimately, in jamming the throttle full open.
This device was not tested and the developer supplied no driveability data. There-
fore, no evaluation was made as to the effects of this device on driveability. The
developer did report, however, that the device has caused no adverse effect on
vehicle performance as noticed by the driver during tests on a chassis dynamometer
and during road driving.
7.1.3.7 Installation Description
The installation of this device consists in removing the presently installed PCV
valve and installing an adjustable flow control valve in the line from the valve
cover to the intake manifold, connecting the control valve linkage to the acceler-
ator pedal linkage, replacing the oil fill cap with a pressure relief cap that does
not admit air, and installing an adapter plate that contains rotating turbine type
blades between the carburetor and intake manifold. Adjustment of the device con-
sists in setting the control valve so that a constant vacuum of one-half inch of
mercury is maintained at the valve cover at idle conditions. It is estimated that
installation of the system should take about one and one-half hours.
Table 7-8 contains a more detailed description of the installation procedure and
identifies tools and special equipment required. Installation can be accomplished
in a normally equipped repair shop with normal skills.
7-18
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Table 7-8. DEVICE 315 CLOSED BLOWBY CONTROL SYSTEM INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove the hose that connects the
PCV valve to the intake manifold
2. Install the adjustable flow control
valve on the inlet to the intake
manifold
3. Remove PCV valve and replace with
hose connector that imposes no
restriction on flow
4. Connect hose between adjustable flow
control valve and connector just
installed
5. Connect linkage from adjustable flow
control valve to accelerator pedal
linkage
6. Remove oil fill cap and replace with
cap that incorporates a pressure
relief valve but does not admit fresh
air
7. Remove carburetor from intake manifold
8. Install adapter plate containing
rotating blades between carburetor
and intake manifold
9. Reinstall carburetor
10 Adjust the flow control valve opening
at engine idle so that the suction
applied to the valve cover is about
0.5 inch of mercury
11 Adjust the linkage so that at higher
engine rpm the flow control valve
will open sufficiently to maintain
the 0.5 inch of mercury vacuum at
the valve cover
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Flow control valve
a. Hand tools
b. hose connector
a. Hand tools
b. Hose
a. Hand tools
b. Linkage
Special oil fill cap
Hand tools
Adapter plate
Hand tools
Vacuum meter
Vacuum meter
Total Time
TIME
(MEN.)
3
6
6
4
10
1
15
3
15
15
15
1.5 hr
7-19
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7.1.3.8 Initial and Recurring Costs
Table 7-9 summarizes the installation costs for this device. From the information
available, it is estimated that the cost for installing this device, including
material, would be $68.75.
Table 7-9. DEVICE 315 CLOSED BLOWBY CONTROL SYSTEM INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
50,000-Mile
Recurring Cost:
Labor
1. Maintenance
DESCRIPTION
a. Flow control valve
b. Adapter plate
a. Special oil fill
cap
b. Linkage
c. Hose connector
d. Hose
Table 7-8
Table 7-8
LABOR HOURS OR
ITEM QUANTITY
1.0 hr
0.5 hr
Total Initial Cost
Paragraph 7.1.3.5
0.75 hr every 25,000
miles @ $12.50 per hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
40.00
10.00
12.50
6.25
68.75
18.75
18.75
87.50
7.1.3.9 Feasibility Summary
This sealed crankcase emission control system would appear to be at least comparable
to the standard PCV valve system in recycling crankcase emissions. Further exhaust
emissions testing would be required to establish the statistical significance of
the device's performance as an exhaust emission control.
7-20
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7.2 OPEN SYSTEMS - RETROFIT TYPE 2.2
7.2.1 Device 160; Closed or Open Blowby Control System
Available in kit form for either the closed or open category crankcase emission
control retrofit system, Device 160 includes a crankcase emission control valve as
an integral part of a crankcase emissions filter assembly. It is offered as a
closed system only in California. This system is presented by its manufacturer as
being available in kits for all vehicles over 140 cubic inch displacement, with
approximately 200,000 installations made to date. This device received accredita-
tion from the California Air Resources Board as a closed crankcase control retrofit
system on 19 November 1963.
7.2.1.1 Physical Description
Figure 7-9 illustrates this device for the closed-system configuration. The filter-
valve assembly of this device (Figure 7-10) is approximately 4 inches in diameter
by 10-1/2 inches tall.. This assembly consists of a case (with upper and lower clip
assemblies) which holds a filter element, a top cover with integral PCV valve as-
sembly, and a residue collection jar which attaches to the bottom. The remainder
of the kit includes the filter-valve assembly installation brackets, hose and fit-
tings for connection from the crankcase through the filter assembly to the intake
manifold, and the ventilation hose from the carburetor air cleaner to the crankcase.
The open system kit has an oil-bath type air cleaner for the air intake into the
crankcase (Figure 7-11).
CLOSED »V1T«M
VOLUMETRIC CONTROL VALVE TO
CONTROL FLOW RATE OF CRANKCASE
VAPORS, TO MAINTAIN SLIGHTLY
LESS THAN ATMOSPHERIC PRESSURE
IN THE CRANKCASE AND TO FUNCTION
AT ALL ENGINE SPEEDS
VAPOR FILTER ELEMENT FILTERS
ALL CRANKCASE VAPORS BEFORE
THEY PASS THROUGH CONTROL VALVE
AND ENTER INTAKE MANIFOLD
RESIDUE JAR TRAPS METALLIC
FUZZ, ACID, VARNISH AND OTHER
IMPURITIES IN CRANKCASE VAPORS
FILTERED CRANKCASE VAPORS ENTER
INTAKE MANIFOLD FOR ENGINE
ECONOMY AND PROTECTION
Figure 7-9. DEVICE 160 CLOSED SYSTEM WITH FILTER TYPICAL INSTALLATION
(DEVELOPER DRAWING)
7-21
-------
VAPO* FILTEI
ELEMENT AND
GASKET
HOSE
FITTINGS
HOSE
(AS APPLICABLE
BB035
Figure 7-10.
DEVICE 160 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER:
PCV VALVE AND FILTER ASSEMBLY
DIRTY
AIR
ENTERS
CLEAN
AIR
ENTERS
Figure 7-11. DEVICE 160 OIL-BATH TYPE AIR CLEANER
FOR OPEN BLOWBY SYSTEMS (DEVELOPER DRAWING)
7-22
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7.2.1.2 Functional Description
The volumetric control valve integral to the cover of the filter/valve assembly pro-
vides the positive crankcase ventilation control in a like manner as provided by an
original equipment PCV valve. The valve restricts blowby flow under high intake
manifold vacuum. According to the developer, the upstream filter element is in-
tended to:
"extract . . . acid, varnish, soot, abrasives, water, sludge, oil
vapor and other impurities (prior to passing blowby gases on to
the intake manifold). The light ends of oil, water vapor, and
combustible materials 'are then drawn through the filtering material
and through the volumetric control valve into the intake manifold
of the engine. Oil vapor for upper lubrication - water vapor for
improved combustion and to dissolve carbon deposits on spark plugs
and in the combustion chamber - combustible vapors from blowby
gases are used as additional fuel."
When supplied as an open type system, an oil bath air filter replaces the standard
dry type filter to provide added protection to the crankcase against ". . . dust,
dirt, abrasive particles, lint and other airborne impurities."
7.2.1.3 Performance Characteristics
v
Emission data obtained in a recent test on a 1972 Cadillac are presented in Table
7-10. However, no baseline test (without device) was conducted for comparison
purposes.
Table 7-10. DEVICE 160 CLOSED OR OPEN BLOWBY CONTROL SYSTEM
WITH FILTER EMISSION TEST RESULTS REPORTED BY DEVELOPER(1)
VEHICLE CONFIGURATION (2)
Without Device
With Device
POLLUTANT (GM/MI)
HC
(3)
0.37
CO
(3)
8.36
NOx
(3)
2.32
Percent Reduction
(3)
(3)
(3)
(1) Results of one 7-cycle, 7-mode cold start test.
(2) 1972 Cadillac with 472-CID engine (2,520 miles indicated on odometer)
Commercial 91 octane gasoline was used.
(3) Not measured; therefore, percent reduction could not be calculated.
By nature of the design, the emission reduction performance of this device should be
similar to that of a standard PCV valve installation. Without definitive data, the
benefit of the filter would be expected primarily in the area of maintaining a clean
emission control valve throughout the maintenance period. There may be indirect
emission control benefit derived from facilitating maintenance of a cleaner engine.
7-23
-------
Emission tests performed in 1960 on three vehicles with and without the device in-
stalled indicated a 50 percent reduction in CO. These were special tests in which
the engine was operated at 2,000 rpm for 60 seconds and then returned to normal idle
speed. A sample of the exhaust gas was taken while the engine was at idle. The
three vehicles were a 1958 Chevrolet V-8 with 25,925 miles, a 1960 Ford Thunderbird
with 2,048 miles, and a 1955 Pontiac V-8 with 40,509 miles.
7.2.1.4 Reliability
The manufacturer estimated that 200,000 units have been installed in light and heavy
duty vehicles since 1935. The manufacturer claimed no failures reported, but did
not estimate device reliability. According to the developer, the device received a
certificate of approval as a crankcase ventilation system from the State of California
Motor Vehicle Control Board on 19 November 1963. In view of the foregoing, and after
examination of the device, it is assumed that its reliability is in excess of 75,000
mean-miles-before-total-failure provided it is installed and maintained in accordance
with the manufacturer's instructions.
7.2.1.5 Maintainability
The manufacturer recommended the following maintenance for automotive applications:
a. During normal operation, the vapor filter element should be inspected
frequently and replaced at least every 12,000 miles. When the element
appears to have little droplets of oil on the outside, it should be changed.
b. Empty residue jar when it becomes one-half full.
c. Clean volumetric control valve located in the cover at each element change.
The valve may be cleaned without removing it from the cover. With the
engine at high idle, or under load, remove the cover and spray a good
grade of smog valve cleaner into valve for approximately 60 seconds. It
is important that the spring not be removed.
It is estimated that the indicated maintenance, including cleaning of the residue
jar, can be performed in less than 15 minutes. No partial repair is anticipated,
although the device hoses are subject to the same deteriorization as other hoses in
the engine compartment and might require preventive maintenance replacement prior to
accumulating 50,000 miles.
7.2.1.6 Driveability and Safety
The developer reported that the device has acceptable driveability characteristics.
No safety hazards were identified.
7.2.1.7 Installation Description
For the closed system, installation consists in mounting the filter-valve unit in
the engine compartment, installing hose fittings, and connecting hoses as shown in
Figure 7-9. For the open system, the oil bath filter unit (Figure 7-11) would be
installed also.
7-24
-------
It is estimated that installation of this device should take about 1.25 hours. Table
7-11 contains a more detailed description of the closed system procedure and identi-
fies the tools and special equipment required. Figure 7-9 shows a typical installa-
tion. Installation can be accomplished in a normally equipped repair shop by the
average mechanic.
Table 7-11. DEVICE 160 CLOSED BLOWBY CONTROL SYSTEM
WITH FILTER INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL; AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT PROCEDURE
1. Install filter unit in vertical position
using the brackets supplied. Check hood
clearance.
2. Install hose adapter fittings to carbu-
retor air cleaner, intake manifold, oil-
fill tube, and road draft tube (sealed).
3. Install hoses from oil-fill cap to car-
buretor air cleaner, from intake manifold
to PCV valve, and from road draft tube to
filter inlet.
4. Adjust idle after engine has reached op-
erating temperature for smoothness and
desired rpm. Mechanical tappets should
be checked after a few days of operation
for proper clearance.
TOOLS, EQUIPMENT
AND FACILITIES
a. Electric drill
b. Hand tools
c. Filter unit
a. Hand tools
b. Adapter fittings
a. Hand tools
b. Hose
a. Hand tools
Total Time
TIME
(MIN. )
30
20
10
15
1.25 hr
Note: For open system, install oil-bath filter at oil-fill tube.
7.2.1.8 Initial and Recurring Costs
Table 7-12 summarizes the installation costs for this device. From the information
available, it is estimated that the cost for installing this device, including
material, will be $46.77 to $69.12. Recurring costs would include both labor and
materials for maintenance of the system in clean operating condition.
7.2.1.9 Feasibility Summary
Device 160, available as a closed or open system (depending on state regulations),
has been on the market for 10 years as a blowby control. It is available in kit
form for vehicles over 140 cubic inch displacement at list prices in the order of
$30 to $50.
7-25
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Table 7-12. DEVICE 160 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Kit
2. Miscellaneous
Labor
1. Install
2. Test and adjust
DESCRIPTION
a. Adapter fittings
b. Filter unit
c. Hose
Mounting bracket
Table 7-11
Table 7-11
LABOR HOURS OR
ITEM QUANTITY
1 hr
1/4 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Maintenance
parts
Labor
1. Maintenance
Filter and cleaning
agent
Paragraph 7.2.1.5
$2.50 average cost
of maintenance
parts every 12,000
miles
0.25 hr every
12,000 miles @
12.50
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
31.15-53.50
(Included
in above)
12.50
3.12
47.77-69.12
10.00
12.50
22.50
91.62
The emission data presented are not conclusive as to the exhaust emission reduction
effectiveness of this device. However, the nature of the device should make it
comparable in performance to a standard PCV valve installation. The filter, in .
addition to facilitating maintenance of cleaner engine parts, may also contribute
to the crankcase emission system upholding its performance during the latter stages
of a maintenance period, as compared to a standard PCV valve installation without
filter. Further emission tests would be required to determine whether the device
provides any significant exhaust emission reduction. As a blowby control, the de-
vice appears to be both technically and economically feasible.
7-26
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7.2.2 Device 427: Closed or Open Blowby Control System with Filter
Device 427 is available in kit form for either the Type 2.1 closed or the Type 2.2
open crankcase emission control retrofit system. It is marketed as an open system
primarily for industrial-type users (e.g., forklift trucks). For passenger vehicle
use, the kit offered is a filter-control valve device that replaces the standard PCV
valve installation in an existing system. The developer also reported that the de-
vice indicates some effectiveness for exhaust CO control.
7.2.2.1 Physical Description
The principal unit of Device 427 is the filter-valve assembly shown in Figure 7-12.
Its overall dimensions are approximately 4-1/2 inches in diameter by 11 inches in
height. Figure 7-13 details its components. Item 6 in Figure 7-13 is the blowby
emission control valve, which is integral to the filter assembly. The filter-valve
assembly is installed as a part of the blowby emission ventilation path between the
engine valve cover or crankcase and the intake manifold, such as that provided by
the typical PCV valve and hose installation. When installed as an open system (e.g.,
for industrial applications) an engine ventilation air filter, approximately 5 inches
in diameter by 7 inches tall, is mounted to provide crankcase inlet air.
411
Figure 7-12. DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM FILTER-VALVE ASSEMBLY
7.2.2.2 Functional Description
Figure 7-14 illustrates the functional flow of this blowby control system. The vol-
umetric control valve, which is integral to the filter assembly, provides crankcase
7-27
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Figure 7-13.
DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM FILTER-VALVE ASSEMBLY DETAILS
(DEVELOPER DRAWING)
VOLUMETRIC VALVE
Figure 7-14.
DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER FUNCTIONAL DIAGRAM
(DEVELOPER DRAWING)
7-28
-------
ventilation control. The device flow control valve has a free metering pin.
It has no spring and uses only vacuum, flow, and gravity for operation. The pis-
ton is triangular in shape to minimize contact surface and ensure correct align-
ment .
The developer stated that his device "reduces engine maintenance and increases engine
efficiency by virtue of the filter trapping emissions which are harmful to the engine,
and passing steam, fuel and oil vapors on through for improved engine operation and
combustion."
7.2.2.3 Performance Characteristics
The developer provided hot start exhaust emission data which compared his device's
performance with that for a standard PCV valve installation. As shown in Table 7-13,
these data indicate that the HC and NOx emissions had no substantial change (a slight
edge in favor of the device) while the CO emissions were reduced by 49 percent.
Table 7-13. DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER EXHAUST
EMISSION REDUCTION PERFORMANCE (DEVELOPER DATA) (1)
VEHICLE
CONFIGURATION (2)
POLLUTANT
HC (PPM)
CO (%)
NOx (PPM)
Without Device
With Device
236
223
0.74
0.38
2,194
2,183
Percent Reduction
5.5
48.6
0.5
(1) Average of two tests with and without device installed in lieu of a con-
ventional PCV valve, using 7-cycle, 7-mode hot start test procedure.
(2) 1968 Ford Galaxie with 302-CID engine, 2-barrel carburetor, and automatic
transmission (73,000+ miles indicated on odometer).
1969 Chevrolet Impala with 350-CID engine, Rochester 4-barrel carburetor,
and automatic transmission (23,000 miles indicated).
Test fuel was Indolene 30.
This developer also provided carburetor air-fuel ratio change test data taken on a
fleet of 10 vehicles. These data revealed that only one of the 10 vehicles exceeded
the California standard of 6 percent allowable enrichment for the 10th decile blowby
conditions; and this was by 0.4 percent. All other data were within the standard,
specified in Reference 121.
7.2.2.4 Reliability
The developer estimated that 600 million miles have been accumulated with the device
installed on 30,000 vehicles. The developer claimed that there has been no reported
7-29
-------
failure. In view of the foregoing, and after review of device drawings and photo-
graphs, it is assumed that the device's reliability would be in excess of 50,000
mean-miles-before-total-failure, if it is installed and maintained in accordance with
the developer's instructions.
7.2.2.5 Maintainability
The developer noted the following maintenance requirements:
a. Visually inspect residue in condensate jar every 5,000 miles' empty and
clean if required
b. Change filter element every 15,000 miles
c. Check condition of hose and valve annually; replace hose and clean valve,
if required.
It is estimated that the indicated maintenance could be performed in less than 15
minutes (0.25 MTTM). A 10,000-MMBM interval is estimated.
No repair is anticipated, although the device hoses are subject to the same deteri-
oration as other hoses in the engine compartment and might require replacement prior
to accumulating 50,000 miles.
7.2.2.6 Driveability and Safety
Table 7-14 summarizes the driveability data supplied by the developer. No safety
hazards have been identified.
Table 7-14. DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER
DRIVEABILITY RESULTS REPORTED BY DEVELOPER
Critical Driveability Elements:
General Driveability Elements
Acceleration Time (0-60 mph):
Deceleration Time (60-40 mph):
Gas Mileage (mpg)
No effect
No effect
Constant at 13.0 sec
Constant at 22.3 sec
No data
7.2.2.7 Installation Description
The installation of this device consists in mounting a filter unit on a bracket in
the engine compartment, replacing any existing PCV valve with the filter-valve
assembly provided, and connecting hoses to filter unit and intake manifold. Idle
adjustment of the engine may be necessary after one week of use.
7-30
-------
It is estimated that installation of the device would take about 1.25 hour. Table 7-15
presents a more detailed description of the installation requirements. Installation
can be accomplished in a normally equipped repair shop by the average mechanic.
7.2.2.8 Initial and Recurring Costs
Table 7-16 summarizes the initial installation cost for this device. From the infor-
mation available, it is estimated that the cost for installing this device, including
material would $67.62. Some recurring cost would be incurred for filter replacement
and maintenance.
7.2.2.9 Feasibility Summary
In addition to providing blowby control, it would appear that this device has some con-
trol capability for exhaust CO. Further testing would be required to establish the
significance of this. With respect to its basic function as a blowby control, the
device appears to be technically feasible. The device is available for passenger ve-
hicles in kit form for retrofit. The filter element of this device (if properly main-
tained) may contribute to the reliability of the emission control valve element, as
well as keep the engine parts cleaner.
7-31
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Table 7-15. DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER
INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Filter unit must be installed
vertically in engine compartment
with connecting hose kept as short
as possible.
Position unit 4 to 12 inches from
exhaust manifold, out of fan air
blast.
2. Connect inlet to PCV replacement
part after original PCV valve is
removed, or install adapters for
filter-valve installation.
3 . Connect return connection to intake
manifold, using the proper adapters
and hoses.
4. Check system for leaks while engine
is idling, pinch inlet hose, engine
speed should change and an audible
click should be heard in 3-5 seconds
as the valve of the unit drops.
CAUTION: If moisture is present in
the jar, release pressure
slowly or filter may be
ruined.
5. After one week's use a slight
adjustment of the carburetor may
be necessary.
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Electric drill
c. Filter unit
Hand tools
a. Hand tools
b. PCV valve replacement
c. Adapters /hose
a. Hand tools
b. Adapters
c. Hose
Hand tools
a. Hand tools
b. Tachometer
Total Time
TIME
(MIN. )
30
20
5
5
15
1.25 hr
7-32
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Table 7-16. DEVICE 427 CLOSED BLOWBY CONTROL SYSTEM WITH FILTER
INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Materials
1. Kit
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Filter unit
b. PCV valve replace-
ment
c. Hose adapters
Hose
)
> Table 7-15
)
LABOR HOURS OR
ITEM QUANTITY
1.0 hr
0.25 hr
Total Initial Costs
50,000-Mile
Recurring Cost:
Materials
1. Filter
Labor
1. Maintenance
Blowby filter
element
Paragraph 7.2.2.5
$3 every 15,000 miles
0.25 hr every 10,000
miles @ $12.50/hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
52.00
(Included
in above)
12.50
3.12
$ 67.62
9.00
15.63
24.63
92.25
7-33
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8 - EVAPORATIVE
CONTROL SYSTEMS
-------
SECTION 8
GROUP 3 RETROFIT METHOD DESCRIPTIONS
EVAPORATIVE EMISSION CONTROL SYSTEMS
Federal emission standards applicable to 1971 models (1970 models in California)
require that fuel systems be equipped or designed to limit fuel evaporation from the
fuel tank and carburetor vents to 6 grams per test (Reference 15). Gasoline tanks
and carburetors on used vehicles before 1970 are vented to the atmosphere. Losses
at the carburetor occur almost entirely during the hot soak period after shutting
off a hot engine. The residual heat causes the temperature of the fuel bowl to rise
to 150° to 200°F, resulting in substantial boiling and vaporization of the fuel in
the carburetor. Losses vary because of many factors, but as much as 29 grams of
fuel per soak period without evaporative controls have been measured from the gas
tank and carburetors of light duty vehicles (Reference 122).
Two evaporative control methods are presently under development and in use on new
cars: the vapor-recovery and the absorption-regeneration systems. The first stores
fuel vapors in the crankcase during engine shutdown, and the second uses an acti-
vated charcoal trap or canister to hold fuel vapors when the engine is stopped.
Evaporative emissions are a function of fuel vapor pressure and ambient temperature.
Current evaporative emission control systems are designed to be used with fuels of
9 pounds or less Reid Vapor Pressure.
A typical new car installation of the absorption-regeneration system is evaluated
in this section, to determine its economic feasibility for retrofit to uncon-
trolled used cars. This system was selected for evaluation because it appears to
be the one favored by most car manufacturers. The typical absorption-regenerative
system is shown in Figure 8-1.
8-1
-------
VAPOR SEPARATOR
SEALED
CAP
PURGE OUTLET
TO AIR CLEANER
THREE-WAY
CHECK VALVE
FUEL TANK
VAPOR INLET
PURGE AIR
INLET
ACTIVATED
CARBON BED
CARBON CANISTER STORAGE
Figure 8-1. ABSORPTION-REGENERATIVE FUEL EVAPORATION
CONTROL SYSTEM
8-2
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8.1 DEVICE 467 ABSORPTION-REGENERATIVE FUEL EVAPORATION CONTROL SYSTEM
Although no retrofit evaporative emission control systems were submitted for evalua-
tion, a brief evaluation of installation procedures and costs are presented for the
absorption-regenerative system to weigh its cost feasibility for retrofit use.
8.1.1 Typical Installation Description
The system installation consists in replacing the presently installed gas tank with
a tank containing the vapor separation installation, installing the vapor separator
in the vicinity of the gas tank, installing a check valve, installing a carbon can-
ister, and connecting hoses from the vapor separator to the carbon canister, and
from the carburetor to the carbon canister to the air filter. Inspection of the
system to make sure there are no vapor leaks is necessary.
Table 8-1 contains a detailed description of the installation procedure and iden-
tifies tools and special equipment required; however, no estimate is made of possible
structural or body modifications required to accommodate the system. Installation
can be accomplished in a normally equipped repair shop by the average mechanic.
8.1.2 Typical Installation Initial and Recurring Cost
Table 8-2 summarizes the estimated initial costs for this device. The material
costs were retail prices and were obtained from the parts department of a new car
dealer (Reference 123) and applied to a 1970 model car with a 390-CID engine. From
the information available, it is estimated that the cost for installing this device,
including material, would be $136.62.
Recurring cost would be incurred because of the requirement to replace the canister
filter every 12,000 miles, and at the same time check for system leaks.
8.1.3 Feasibility Summary
Based on the costs and potential complexity of installation, it does not appear
that a fuel evaporative system of the production canister type configuration would
be economically feasible for retrofit applications. The principal cost impact is
represented by the parts and not labor. Thus it would appear that a system of less
design complexity would have to be devised for retrofit use.
8-3
-------
Table 8-1. DEVICE 467 ABSORPTION-REGENERATIVE FUEL EVAPORATION CONTROL
SYSTEM INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove presently installed gas tank.
2. Install sealed gas tank containing
vapor separation components.
3. Install vapor separator under car
in vicinity of gas tank.
4. Connect vapor separator to gas tank.
5. Install three-way check valve in
vicinity of gas tank.
6. Connect vapor separator to check
valve and install line under body
of car to the engine compartment.
7. Install carbon canister in engine
compartment.
8. Install hose connecter in body of
air-filter
9. Connect line from three-way check
valve to carbon canister to air
filter.
10. Install connecter in fuel bowl of
carburetor
11. Connect carburetor to check valve
to carbon canister.
12. Inspect for leaks
TOOLS, EQUIPMENT
AND FACILITIES
a. Car lift
b. Hand tools
a. Hand tools
b. Gas tank
a. Hand tools
b. Vapor separator
a. Hand tools
b. Hose, clamps
a. Hand tools
b. Hose, clamps
c. Three-way check valve
a. Hand tools
b. Hose, clamps
a. Hand tools
b. Carbon canister
a. Hand tools
b. Hose connecter
a. Hand tools
b. Hose, clamps
a. Hand tools
b. Hose connecter
a. Hand tools
b. Hose, clamps
c. Check valve
Total Time
TIME
(MIN.)
30
30
60
5
15
20
20
15
10
15
5
15
4.0 hrs
8-4
-------
Table 8-2. DEVICE 467 ABSORPTION-REGENERATIVE FUEL EVAPORATION CONTROL
SYSTEM INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2 . Test and adjust
DESCRIPTION
a. Carbon canister
b. Gas tank
c. Vapor separator
d. Three-way check
valve
e. Check valve
Hose, clamps, and
hose connector
50,000-Mile
Recurring Cost:
Material
1.. Filter
Labor
1. Inspection
Paragraph 8.1.2
Filter replacement
and inspection for
leaks
LABOR HOURS OR
ITEM QUANTITY
3.0 hrs
0.25 hr
Total Initial Cost
$1.00 every 12,000
miles
0.25 hr every
12,000 miles @
$12.50/hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
21.00
42.00
22.00
3.00
3.00
5.00
37.50
3.12
136.62
4.00
12.50
16.50
153.12
8-5
-------
9 - EMISSION
CONTROL COMBINATIONS
-------
SECTION 9
GROUP 4 RETROFIT METHOD DESCRIPTIONS EMISSION
CONTROL COMBINATIONS
There are three basic types of automobile emissions; these are exhaust emissions,
crankcase emissions, and fuel system evaporative emissions. These have been classi-
fied as Groups 1, 2, and 3 and devices falling within those groups have been
described in previous paragraphs. As described in Section 2, exhaust emissions
account for 60 percent of the total HC emissions of an uncontrolled car, 100 percent
of total CO emissions and 100 percent of NOx emissions. Crankcase emissions account
for 20 percent of the HC total, and evaporative emissions account for 20 percent of
the HC total.
Group 4 emission control devices involve a combination of any two or all three of
groups 1, 2, and 3. Table 9-1 lists the four combination types studied in the
retrofit program.
Table 9-1. GROUP 4 EMISSION CONTROL COMBINATION RETROFIT DEVICES
DEVICE
NO.
NOMENCLATURE
59
165
408
469
Three-Stage Exhaust Gas Control System
Exhaust Gas Afterburner/Recirculation with Blowby and Fuel
Evaporation Recirculation
Exhaust Gas and Blowby Recirculation with Intake Vacuum Control
and Turbulent Mixing
Thermal Reactor with Exhaust Gas Recirculation and Particulate Control
9.1 DEVICE 59: THREE-STAGE EXHAUST GAS CONTROL SYSTEM
A single prototype unit of this device has been fabricated by the developer and
tested (March, 1970) on a 1964 automobile using 1968 Federal (seven mode-seven
cycle) cold start test procedures. Results of this test indicate reductions
in HC, CO, and NOx emissions.
The developer has declined to provide any descriptive information on this
device except to describe it as a three-stage exhaust device.
9-1
-------
9.1.1 Physical Description
The developer has declined to provide any descriptive information on this
device.
9.1.2 Functional Description
The developer declined to provide any functional description of this device
except to state that it is a three-stage exhaust device.
9.1.3 Performance Characteristics
Emission performance characteristics supplied by the developer are summarized
in Table 9-2.
Table 9-2. DEVICE 59 THREE-STAGE EXHAUST GAS CONTROL SYSTEM EMISSION
TEST RESULTS (DEVELOPER'S DATA) (1)
VEHICLE
CONFIGURATION
Without Device
With Device
Percent Reduction
POLLUTANT
HC
(PPM)
811
552
32
CO
(%)
4.65
3.80
18.3
NOx
(PPM)
602
535
11
(1) 1968 Federal Procedure (7-mode, 7-cycle) Cold Start Tests - 1964
Chevrolet Impala, 283-CID, 2V carburetor, automatic transmission.
One test conducted by Olson Laboratories, Dearborn, Michigan,
March 4, 1970.
i
9.1.4 Reliability
The developer provided no estimate of device reliability and insufficient informa-
tion was available for reliability evaluation. No reliability estimate could be
made.
9.1.5 Maintainability
The developer states in response to the inquiry for periodic maintenance/
inspection requirements: "One year - and cost is pennies." Sufficient information
was not available to evaluate the device for maintenance requirements.
9.1.6 Driveability and Safety
Sufficient information was not available to perform a safety hazard analysis.
This device was not tested and the driveability data was supplied by the developer.
Table 9-3 summarizes this information.
9-2
-------
Table 9-3. DEVICE 59 THREE-STAGE EXHAUST GAS CONTROL SYSTEM
DRIVEABILITY (DEVELOPER DATA)
Critical Driveability Elements
General Driveability Elements
Acceleration Time (0-60 mph)
Deceleration Time (60-40 mph)
Gas Mileage (mpg)
Without Device
With Device
No affect
No affect
Increased from 23.3
Increased from 24.7
to 28.7 sec
to 25.7 sec
City Highway
10.2 17.1
17.8 15.6
9.1.7 Installation Description
There was insufficient installation description information available from the
developer.
9.1.8 Initial and Recurring Costs
The initial and recurring costs information was not available from the developer.
9.1.9 Feasibility Summary
Insufficient information was available to determine the feasibility of this device.
9-3
-------
9.2 DEVICE 165: EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATION
This device performs the combination of functions its title implies, using an
integrated system. They are differentiated from systems in which exhaust gas
recirculation, crankcase emissions, and evaporative emissions are controlled
by separate devices which function independently.
This device is an integral system which performs functions of exhaust gas
recirculation, crankcase emission, and evaporative emission control. These
functions are performed by drawing a portion of the exhaust gas into an "after-
burner unit" where, with no addition of air, combustion is completed in the
presence of a continuously firing spark plug.
Afterburner gases are then passed through a heat exchanger for cooling and then
divided into two routes for recirculation into the induction system. One route
is direct to the carburetor inlet through the air cleaner. A second route
ports to the intake manifold through a, micro (micron size) filter. Vapors from
the gas tank and crankcase are piped to a metering assembly, and then fed into
the exhaust recirculation line entering the intake manifold. Positive flow of
gasoline tank vapor, crankcase vapor, and recirculated exhaust gas are main-
tained by intake manifold vacuum. A single prototype device has been developed
for installation in a 1965 Ford Falcon (200 CID, single-barrel carburetor).
9.2.1 Physical Description
A photograph of the device installed in a 1965 Ford Falcon is shown in Fig-
ure 9-1. Principal elements of the prototype device are:
a. An exhaust adapter which apportions exhaust flow between the after-
burner and exhaust pipe, and receives returning flow from the
afterburner.
b. An afterburner consisting of a cast iron chamber and bolted closure
having three ports - inlet, return to exhaust pipe (bypass flow),
and discharge to heat exchanger.
c. A coil and spark plug assembly which provides a continuous spark to
the afterburner chamber.
d. A finned tube heat exchanger - formed into a 90-degree elbow for the
prototype installation. (The heat exchanger discharges to a T-fitting
where flow is split between a hose line to the carburetor air cleaner
and a steel line connected to the fuel evaporation line to the intake
manifold.)
e. A stainless steel mesh micro filter.
f. Hoses from the gasoline tank and valve cover (crankcase emissions) are
ported to a metering assembly (adjustable needle-valves) which are
adjusted to control intake manifold suction on the gasoline tank and
crankcase vapors.
9-5
-------
Figure 9-1. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATION INSTALLATION
g. A line from the metering assembly which passes fuel and crankcase
vapors into the line discharging recirculated exhaust gas into the
intake manifold.
9.2.2 Functional Description
The functions performed by this system are related by the functional block dia-
gram of Figure 9-2. As indicated, crankcase and gasoline tank vapors are drawn,
under intake manifold suction, to a metering device. The metering device appor-
tions and restricts the vapor flow from these sources. The vapors are then
mixed with recirculated exhaust gas and drawn into the intake manifold.
Reduction of CO and HC emissions are controlled by tapping a portion of the nor-
mal exhaust gas and porting it to an accumulator type afterburner where com-
bustion of unburned CO and HC reportedly occurs under the influence of a con-
tinuous high voltage spark. No air is ported to the afterburner in this unit.
A portion of the exhaust passed through the afterburner is returned to the
exhaust pipe for discharge to the atmosphere. The remaining portion of the
exhaust gas is passed through a finned tube heat exchanger and split along
two paths. Along one path the gas is directed to the carburetor air cleaner,
filtered by the air cleaner, and mixed with air entering the carburetor. The
9-6
-------
HC EMISSIONS
EXHAUST GASES
GAS TANK
VAPORS
REDUCED HC EMISSIONS
CRANKCASE
VAPORS
(BLOWBY)
GASOLINE AND
CRANKCASE
VAPOR
FILTER
INTAKE
MANIFOLD
RECIRCULATED
AND AFTERBURNED
EXHAUST
FILTERING
EXHAUST
GAS
NORM
EXHAUST
AFTERBURNING-
COMPLETION OF
COMBUSTION
AFTERBURNED
EXHAUST WITH
REDUCED CO, HC
COOLING
HEAT
EXCHANGER
CYLINDERS
REDUCED
COMBUSTION
TEMPERATURE
AIR + RECIRCULATED
AND AFTERBURNED
EXHAUST
CARBURETOR
AIR
CLEANER
886
Figure 9-2. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATION FUNCTIONAL BLOCK DIAGRAM
heated mixture of recirculated exhaust and air is intended to provide increased
vaporization of gasoline to provide a more homogeneous air fuel mixture.
Exhaust gas directed along the secondary path passes through a micro (micron)
size filter and mixes with gasoline and crankcase vapors before entering the
intake manifold. Overall effect of recirculated exhaust gas is to provide an
inert diluent to the fuel-air mixture which lowers combustion temperature,
resulting in reduced formation of NOx.
9.2.3 Performance Characteristics
The emission reduction test results of the subject retrofit device as reported by
the developer are summarized in Table 9-4. All of the tests used a six cylinder
1965 Ford Falcon test vehicle (200 CID) . Recent data measured by Olson Labora-
tories are also included in Table 9-4. No baseline data were reported to cal-
culate emission reduction.
9-7
-------
Table 9-4. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY AND
FUEL EVAPORATION RECIRCULATION EXHAUST EMISSION TEST RESULTS
VEHICLE
CONFIGURATION
POLLUTANT
HC
(PPM)
CO
NOx
(PPM)
1. Developer Data on 1965 Ford Falcon 200 CID
engine with device:
a. May 1970 Fed. Test (1)
b. June 1970 Test (169-1) (2)
c. Dec. 1970 Test (169-1) (2)
d. June 1971 Test (19603) (2)
2. OLI test data on 1965 Ford Falcon 200 CID
engine with device (3)
556
326
188
249
329
2.3
0.97
1.04
0.59
1.53
716 (NO)
13 (N02)
704
1083
726
(1) Results of one standard Federal 7-mode (cold start) exhaust emission
test.
(2) California Air Resources Board emission test results from one test using
California 7-mode (hot start) cycles.
(3) Results of one standard Federal hot start emission test.
9.2.4 Reliability
Insufficient retrofit developer data were available to determine mean-miles-
before-total-failure (MMBTF). However, it appears that the afterburner
ignition subsystem reliability would be the primary constraint to meeting
the system MMBTF of 50,000 miles. Developer data indicates that the ignition
device is a glow plug, in which case replacement would be required prior to
burnout to achieve a system MMBTF of 50,000 miles. Examination of an in-
stalled system indicated that the ignition device is a spark plug. It appeared
that the spark plug is driven by an ignition coil with a vibrator to actuate
the primary. If this is the case, the vibrator and spark plug would require
maintenance prior to failure to achieve an MMBTF of 50,000 miles.
If it can be assumed the foregoing have been considered in the design (pro-
vision for maintenance before failure and component selection), then a system
MMBTF of 50,000 miles appears achievable.
9-8
-------
9.2.5 Maintainability
Minimum maintenance would require cleaning or replacement of the afterburner ignition
device, inspection/adjustment of the ignition power source, and cleaning or replace-
ment of the "Micro Clean Filtering and Air Intake Unit." Such maintenance could be
accomplished in one-half hour every 12,000 miles provided it has been a design con-
sideration to permit ease of access for inspection and removal and replacement of
components when necessary.
Additional maintenance which might be required cannot be determined without long term
test data relating to waste products deposition in the various gas transport lines
throughout the system. Such data could indicate the need for periodic cleaning of
one or more lines.
9.2.6 Driveability and Safety
Critical review of the final design should place primary emphasis on interface of the
system with the fuel tank. Any fuel vapor in the interface might constitute an
explosive train initiated by backfire through an intake valve and the evaporative
control line which terminates in the gas tank.
This device was not tested for driveability in the retrofit program. The following
data were supplied by the developer. Table 9-5 summarizes this information.
Table 9-5. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY AND
FUEL EVAPORATION RECIRCULATION DRIVEABILITY (DEVELOPER DATA)
Critical Driveability Elements
General Driveability Elements
Acceleration Time (0-60 mph)
Deceleration Time (60-40 mph)
Gas Mileage (mpg)
No affect
No affect
No data
No data
No data
9.2.7 Installation Description
The installation of this device consists of installing an afterburner unit on the
exhaust line, installing a pipe fitting into the intake manifold, connecting the
afterburner unit to the intake to permit gases to flow to intake, installing line
from fuel tank emission accumulator, installing line from crankcase emission, con-
necting these lines to intake manifold, installing high voltage coil, glow plug,
flow control valves, and micro-cleaning filter. Adjustment of the device consists
of regulating the flow through the several control valves to give the best overall
engine performance.
9-9
-------
Table 9-6 contains a more detailed description of the installation procedures. Fig-
ure 9-2 is a functional block diagram that illustrates the manner in which this de-
vice would be installed. Installation can be accomplished in a normally equipped
repair shop with normal skills.
9.2.8 Initial and Recurring Costs
The developer estimates the retail cost of the device at $175 for material and in-
stallation cost for labor at $50. Table 9-7 summarizes the costs for this instal-
lation. From the information available, it is estimated that the cost for installing
this device, including material, would be $237.50.
9.2.9 Feasibility Summary
Limited test data provided by the developer did not include baseline emissions and
the emission reduction effectiveness could not be calculated. The device is, however,
too complex and costly to be considered for retrofit application.
Complexity of the device is demonstrated by the following factors:
a. The device incorporates exhaust afterburning, exhaust gas recirculation,
crankcase vapor recirculation, and fuel tank vapor suction in a single
integrated system. The interactions between these various functions
and their effect on overall emission may vary from model to model.
b. The system requires interface penetrations at five points (exhaust
manifold, fuel tank, crankcase, air cleaner, intake manifold) on the
vehicle, installation of three components and five lines.
The existing prototype unit will require substantial development and redesign before
it can be manufactured in quantity. The developer's estimate of an initial cost of
$175 per unit is a rough estimate and is not based on a reliable manufacturing cost
analysis. The developer currently has no plan for marketing this device.
9-10
-------
Table 9-6. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATION INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
TOOLS, EQUIPMENT
AND FACILITIES
TIME
(MEN.)
1. Remove hose fitting from intake"
manifold and drill and tap for 3/8-
inch NPT pipe fitting.
2. Drill 1-1/16-inch diameter hole and
ream with 1-inch pipe taper reamer
into exhaust manifold to fit locking
taper fitting adapter of afterburner
unit.
3. Disassemble exhaust inlet pipe and
install stainless steel perforated
buffer disc; reassemble.
4. Burn out 1-5/16-inch hole in exhaust
inlet pipe and weld connection.
5. Install two engine mounting brackets
and mounting strap for afterburner
unit.
6. Install afterburner unit.
7. Install line from exhaust inlet.
8. Install heat transfer unit to after-
burner unit.
9. Install line from heat transfer unit
to microcleaning filter and air bleed
unit.
10. Install line from heat transfer unit
to air intake.
11. Install Y-type filter to intake
manifold.
12. Install line from microcleaning filtei
to Y type filter.
a. Hand tools
b. tlectric drill
c. Threading die
a. Electric drill
b. Pipe reamer
a. iiand topis
b. Buffer disc
a. Oxyacetalyene torch
b. Connection fitting
a. Hand tools
b. Mounting brackets § straps
a. Hand tools
b. Afterburner unit
a. Pipe
b. Hand- tools
a. Hand tools
b. Heat transfer unit
a. Hand tools
b. Pipe
c. Microcleaning filter unit
a. Hand tools
b. Pipe
c. Flow control valve
a. Hand tools
b. Y type filter
a. Hand tools
b. Pipe
c. Flow control valve
15
15
15
20
30
10
10
15
15
20
10
9-11
-------
Table 9-6. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATION INSTALLATION PROCEDURE (CONCL)
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
13. Install line from Y-type filter' to
fuel tank emission accumulator.
14. Install line from crankcase emission
blowby vent to Y-type filter
15. Install glow plug in afterburner
unit
16. Install high voltage coil for
glow plug.
17. Wire glow plug to coil, and coil to
primary ignition circuit
18. Adjust flow rates through control
valves to give best overall
driveability.
TOOLS, EQUIPMENT
AND FACILITIES
a. Hand tools
b. Pipe
c. Flow control valve
d. Fuel evaporate flow control
valve
a. Hand tools
b. Pipe
a. Hand tools
b . Glow plug
a. Hand tools
b. High voltage coil
a. Hand tools
b. Wire
a. Hand tools
b. Engine analyzer
Total Time
TIME
(MEN.)
20
10
5
10
10
60
5 hrs
9-12
-------
Table 9-7. DEVICE 165 EXHAUST GAS AFTERBURNER/RECIRCULATION WITH BLOWBY
AND FUEL EVAPORATION RECIRCULATIQN INITIAL AND RECURRING COST
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Buffer disc
b. Y-type filter
afterburner
c. Gloplug
d. Heat transfer unit
e. Microcleaning
filter unit
f. Flow control valves
a. Connection fitting
b. Mounting brackets
and straps
c. Pipe
d. High voltage coil
e. Electric wire
LABOR HOURS OR
ITEM QUANTITY
4 hrs
1 hr
Total Initial Cost
50,000-Mile
Recurring Cost:
Material
1. Maintenance
Parts
Labor
1. Inspection
Par. 9.2.5
Par. 9.2.5
Average cost of
maintenance parts
0,5 hr every 12,000
miles @ $12.50 per
hr
Total Recurring Cost
TOTAL COSTS
COST
(DOLLARS)
175.00
(Included
in above)
50.00
12.50
$ 237.50
2.50
25.00
$ 27.50
$ 265.00
9-13
-------
9.3 DEVICE 408: EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE VACUUM
CONTROL AND TURBULENT MIXING
9.3.1 Physical Description
Device 408 consists of an adapter plate which fits under the carburetor and
connects by hose to the crankcase blowby recirculation system. It also con-
nects to the exhaust manifold through a flexible metal conduit. The adapter
plate is about 3/4 inch in thickness, 1 inch wider than the carburetor base,
and 2 inches longer than the carburetor base. The adapter plate has a device
in each carburetor throat to induce "turbulation" into the air-fuel mixture as
it flows into the intake manifold. In front and in the rear of the adaptor
plate are tubular sections which contain vacuum operated valves for control of
the exhaust and blowby gases. Figures 9-3 and 9-4 are photographs of the
device.
9.3.2 Functional Description
Device 408 operates on the principle of injecting exhaust and blowby gases
into the intake manifold and creating "turbulent" flow in the manifold. The
following description was provided by the developer:
"As a source of heat, the high temperature air of recycled exhaust
gas is drawn from the exhaust sytem through a heat exchanger into
the "little black box" where it is mixed in ratio with the blowby
gases drawn from the crankcase of t;he vehicle. During the decel-
eration cycle of an automobile the deceleration valve of the
device opens to capacity providing an unrestricted flow of recycled
exhaust gases beneath the carburetor thereby relieving the vacuum
demand upon the idling circuit of the carburetor .....
"A high efficiency turbulator element is built into the base of
each device throat which imparts a vortical turbulence inertial
action to the air-fuel mixture as it passes through the turbulator,
thus compounding the mixing and blending of the now preheated
gaseous gasoline vapors and air to the point of saturation and
uniformity.
"The self-compensating, vacuum actuated, bleed air regulator or
acceleration valve opens progressively in ratio to diminishing
manifold vacuum of the engine, thus maintaining a progressive
volume increase in the preheated air, gasses and fumes approxi-
mately parallel, percentage wise, to the increasing volume of
gasoline passing through the carburetor and device. Hence, an
ample quantity of preheated air, gasses and fumes are present to
vaporize the increased volume of gasoline.
"By replacing the o.e.m. oil filter breather cap of any vehicle
with a one-way, inlet only, type filler breather cap, the device
readily becomes a closed positive crankcase ventilation device
capable of controlling the severest cases of crankcase blowby
emissions."
9-15
-------
Figure 9-3.
BB134
DEVICE 408 EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE
VACUUM CONTROL AND TURBULENT MIXING ASSEMBLY
>
Figure 9-4. DEVICE 408 EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE
VACUUM CONTROL AND TURBULENT MIXING COMPONENTS
9-16
-------
9.3.3 Performance Characteristics
No exhaust emission data or driveability data were supplied for this device;
therefore, it is not possible to evaluate performance.
9.3.4 Reliability
Functionally, the device consists of gas passages and two spring-loaded valves.
The device appears capable of demonstrating a reliability in excess of 50,000
mean-miles-before-total-failure with proper maintenance. It is essential that
corrosion resistant materials be utilized where required to enable appropriate
disassembly for maintenance.
9.3.5 Maintainability
The following maintenance should be performed:
a. The crankcase blowby device valve should be inspected and cleaned at
the same intervals as the standard PCV valve.
b. The device exhaust gas control valve should be inspected every
12,000 miles for exhaust products build-up or metal erosion and
cleaned or replaced as required.
It is estimated that the required routine maintenance can be performed in
30 minutes provided that components are not corroded and can be disassembled.
Additionally, the device should be cleaned, particularly orifices and the fixed
turbine blades, every time the carburetor is cleaned or overhauled. Broken
valve springs or eroded valves can be replaced during routine maintenance. No
other repairs are anticipated.
9.3.6 Driveability and Safety
The probability of igniting the carbureted fuel mixture is increased by the
method of exhaust gas recirculation. This could constitute a safety hazard
if the basic carburetor used with the device is not capable of suppressing
a backfire without conflagration of the raw fuel or the air filter. No
other potential safety hazards have been identified.
This device was not tested by OLI and driveability data were supplied by the
developer. Table 9-8 summarizes this information.
9.3.7 Installation Description
The installation of this device consists of installing an induction unit
between the carburetor and intake manifold, connecting a flexible metal conduit
from the exhaust line to the induction unit, attaching the hose from the PCV
valve to the induction unit, and replacing the oil fill breather cap with a
new one-way inlet flow only cap. Adjustment of the device consists of setting
the acceleration valve and deceleration valve. T.he acceleration valve is
adjusted to provide the minimum exhaust gas inlet at approximately 21 inches
9-17
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Table 9-8. DEVICE 408 EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE VAC-
UUM CONTROL AND TURBULENT MIXING DRIVEABILITY (DEVELOPER DATA)
Critical Driveability Elements
General Driveability Elements
Acceleration Time (0-60 mph)
Deceleration Time (60-40 mph)
Gas Mileage (mpg)
Increased stall during both cold start
and hot start acceleration
No affect
Constant at 19.1 sec
Constant at 9.5 sec
No data
of vacuum at idle. The deceleration valve is adjusted to open at approxi-
mately 25 inches of vacuum during deceleration.
The developer estimates that the installation of the device should take about
one hour. Table 9-9 contains a more detailed description of the installation
procedure and identifies tools and special equipment required. Installation
can be accomplished in a normally equipped repair shop with normal skills.
9.3.8 Initial and Recurring Costs
The developer estimates that the cost of the device is $20. Table 9-10 summa-
rizes the installation costs. From the information available, it is estimated
that the cost for installing this device, including material, would be $35.62.
9.3.9 Feasibility Summary
Due to the lack of developer emission data, the evaluation of the feasibility
of this device for retrofit control of exhaust emissions from used cars is
inconclusive.
A detailed marketing plan has been supplied involving dealer franchises but at
the present time the unit is not available on the market.
9-18
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Table 9-9. DEVICE 408 EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE
VACUUM CONTROL AND TURBULENT MIXING.,, INSTALLATION PROCEDURE
MINIMUM AVERAGE SKILL LEVEL: AUTOMOTIVE MECHANIC
INSTALLATION AND ADJUSTMENT
PROCEDURE
1. Remove carburetor and studs to -intake
manifold.
2. Install new longer studs in intake
manifold.
3. Install induction unit on intake
manifold so that it is installed
between carburetor and manifold.
4. Reinstall carburetor on engine.
5. Burn hole in exhaust line between
muffler and manifold.
6. Install connection to exhaust line.
7. Connect flexible metal conduit from
connection on exhaust line to induc-
tion unit on intake manifold.
8. Attach hose from PCV to induction.
9. Replace oil-fill breather cap with
one-way inlet flow only cap.
10. Adjustment of the device is made to
provide the minimum exhaust gas and
fume inlet at the approximately
21-inches of vacuum at idle. This
is made on the acceleration valve.
11. Adjustment of the deceleration valve
is made to provide the valve to open
at approximately 25-inches of
vacuum during deceleration.
TOOLS, EQUIPMENT
AND FACILITIES
Hand tools
Hand tools - Longer studs
for intake manifold
Hand tools
Induction unit
Hand tools
Oxyacetylene torch
a. Hand tools
b. Connection clamps
a. Hand tools
b. Flexible metal conduit
c. Clamps
a. Hose, clamps
Special oil-fill breather
cap
Engine analyzer
Engine analyzer
Total Time
TIME
(MIN. )
15
4
6
15
7
8
2
1
8
7
1.25 hrs
9-19
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Table 9-10. DEVICE 408 EXHAUST GAS AND BLOWBY RECIRCULATION WITH INTAKE
VACUUM CONTROL AND TURBULENT MIXING INITIAL AND RECURRING COSTS
ITEM
Initial Cost:
Material
1. Device
2. Miscellaneous
Labor
1. Installation
2. Test and adjust
DESCRIPTION
a. Induction unit
b. Flexible metal
condui t
c. Hose
d. Special oil
filler
e. Breather cap
a. Larger studs for
intake manifold
b. Connection clamps
LABOR HOURS OR
ITEM QUANTITY
1 hr
0.25 hr
Total Initial Cost
75,000-Mile
Recurring Cost:
Material
1. Maintenance
Parts
Labor
1. Inspection
Average cost of
maintenance parts
0.5 hr every 12,000
miles @ $12.50 per
hr
Total Recurring Cost
TOTAL COST
COST
(DOLLARS)
20.00
(Including
above)
12.50
3.12
$ 35.62
2.00
39.00
$ 41.00
$ 76.62
9-20
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9.4 DEVICE 469: THERMAL REACTOR WITH EXHAUST GAS RECIRCULATION AND
PARTICULATE CONTROL
This device, according to the developer's report (Reference 73), is a total
exhaust emission control system.
The thermal reactor used in this system is a device 244 model (described in
Section 3, paragraph 3.2.1).
9.4.1 Physical Description
This emission control system combines three major devices. These are:
a. An exhaust manifold thermal reactor to control the hydrocarbons and
carbon monoxide. (1)
b. An exhaust gas recirculation system to control nitrogen oxide levels.
c. Particulate trap.
9.4.2 Functional Description
9.4.2.1 Thermal Reactor
The exhaust manifold reactors are mounted on the engine in place of the con-
ventional exhaust manifolds and air is injected into the exhaust ports from
the air injection system used on many production cars. The reactors provide
a high-temperature zone in which the hydrocarbons and carbon monoxide are
oxidized thermally to carbon dioxide and water. A detailed description is
presented for this reactor in Section 3.
9.4.2.2 Exhaust Gas Recirculation
A portion of the exhaust gas is taken from the exhaust pipe just ahead of the
muffler and is directed into the carburetor between the venturi section and
the throttle plate, Figure 9-5. The introduction of the exhaust gas into the
carburetor dilutes the incoming fuel/air mixture to the engine and lowers the
peak combustion temperatures within the cylinder, thus reducing the formation
of nitrogen oxides. The amount of exhaust gas which enters the carburetor is
metered by an orifice located in the recirculation line. The system was set
to give a recirculation rate of approximately 15 percent. A vacuum-operated,
on-off valve shuts off the recirculation at idle to give smooth engine opera-
tion and also at wide-open-throttle to prevent loss in vehicle performance.
A small cyclone separator to remove particles which might plug the recircu-
lation system can be incorporated in the recirculation line if needed.
(1) The reactor system alone was evaluated and presented as Device 244 in
Section 3, paragraph 3.2.1.
9-21
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METERING,
ORIFICE I
EGR ON/OFF VALVE
CVCLONEp ,'
FLEXIBLE
TUBING
CARBURETOR(
PLATE
Figure 9-5. EXHAUST GAS RECIRCULATION SYSTEM
9.4.2.3 Exhaust Particulate Trap
To trap particulate matter effectively, three important functions must be accom-
plished by the trapping system. First, the exhaust must be cooled so that
the potential particulate matter can solidify in the exhaust stream. Secondly,
the fine particles must be agglomerated into larger particles so that they can
be easily separated from the gases. Finally, the particles must be separated
from the gas stream with some device such as a cyclone trap and then retained in
the exhaust system.
A schematic diagram of an exhaust particulate trapping svstem employing these
three principles is shown in Figure 9-6- This system will be called Svstem A.
The cooling of the exhaust gas as it passes through a dual exhaust system is
enhanced by the use of fluted pipes which provide more surface area than ordi-
nary pipes and thus more effective cooling. Each exhaust line empties into a
trap box in which the exhaust gas first passes through wire mesh to agglomerate
the particles and then through a cyclone separator to separate the particles
from the gas. The 'separated particles are collected in one portion of the box
and the exhaust gas exits to the atmosphere through a tailpipe. The boxes have
sufficient capacity to store all the separated lead salts for the life of the
car, or 100,000 miles. The connection between the two exhaust lines just ahead
of the trap boxes merely serves to balance the pressure in the two exhaust
.FLUTED EXHAUST PIPE
CYCLONE
TRAPS
Figure 9-6. EXHAUST PARTICULATE MATTER TRAPPING SYSTEM A
9-22
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lines. A photograph of a trap box cut away to show the cyclone separator is
shown in Figure 9-7. The wire mesh packing is omitted to permit a view of the
cyclone separator.
•' .
-^ ; f...
.,• ; ' ' i""'
I •"$ i........
r. <" :
^ i ..,.
Figure 9-7. CYCLONE SEPARATOR AND COLLECTION BOX
9.4.3 Performance Characteristics
Table 9-11 shows that the reactor performance with exhaust gas recirculation
(EGR) exhibits substantial reductions (77 and 60 percent for HC and NOx) from
similar test cars with the auto manufacturer emission control systems installed.
To measure particulate emission rates, the vehicles were operated on a pro-
grammed chassis dynamometer using a modification of the AMA driving cycle
(Reference 73). To simulate motorist-type driving the 40.7-mile AMA cycle
was divided into nine trips ranging in length from less than one mile to a
maximum of 15 miles. The vehicles were stopped at the end of each trip and
the engines and exhaust systems force-cooled. At the time these tests were
being conducted, mileage accumulation was being conducted on both cars A
and B. No subsequent data were reported by the developer. Also at the time
of these tests (November 20, 1971), measuring techniques had not been es-
tablished by the Federal Government (Reference 73).
The developer reported that the combined control systems (reactor, EGR, and
trap) also reduce particulates as indicated below (Reference 73).
. Particulate Emission Rate (GM/MI)
Leaded Salts Total Particulate Matter
Car A 0.033 0.041
Car B 0.017 0.029
9-23
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Table 9-11. DEVICE 469 EMISSION REDUCTION RESULTS
(EPA REFERENCES 74 AND 75)(1)
VEHICLE
CONFIGURATION
Without Device (2)
With Device (1)
Percent Reduction
POLLUTANT (GM/MI)
HC
3.07
0.60
80
CO
37.35
20.74
44
NOx
3.24
1.12
65
(1) Results are from two EPA 9-Cycle, 7-Mode Tests (Reference 16).
(2) Average baseline data for six 1970 350-CID vehicles with standard
factory emission control equipment. Used in this report for
baseline comparison purposes only.
9.4.4 Reliability
The developer's report provided some information on the reliability of the
combined systems. Although not yet tested as extensively as exhaust manifold
reactors, the exhaust gas recirculation system had been operated for 50,000
miles without maintenance. The vehicle has been operated on a programmed
chassis dynamometer on a non-detergent fuel containing 3 grams of lead per
gallon and without a cyclone separator in the exhaust gas recirculation line.
During this entire test the exhaust gas recirculation system required no main-
tenance. The gas recirculation rate remained at 15 percent and the nitrogen
oxide levels did not change. Some deposits accumulated in the throttle section
of the carburetor. Additional tests were being conducted with a fuel contain-
ing a carburetor detergent (Reference 73).
The particulate trapping systems also have not been tested as extensively as
exhaust manifold reactors but various versions reportedly have been operated
for up to 64,000 miles without maintenance or attention.
Reference 2 does point out some reliability problems for the combination
systems described here.
The developer supplied six cars to California Air Resources Board in the fall
of 1970 for its evaluation in a two-year program. These cars were 1970
Chevrolets with 350 CID engines and automatic transmissions, and were equipped
with the DuPont particulate-trapping system as well as thermal reactor and EGR.
The six test cars, along with six production vehicles for comparison, were
assigned to the State Motor Pool in California for normal driving service by
9-24
-------
state employees. In June 1971, the average of the odometer readings of the six
vehicles was 17,954 miles. As the vehicles had about 3000 miles of operation
prior to incorporation of the emission control system, about 15,000 miles of
durability testing of the emission control system were actually logged.
Near the end of August 1971, a failure of a timing chain occurred in one of the
six test vehicles. The failure was described as an elongation of the timing
chain, which eventually caused a hole to be rubbed in its cover. None of the
six vehicles in the control fleet was affected.
The developer stated that similar wear was observed in three of the six California
Air Resources Board test cars. Symptoms of similar wear had been previously
detected in three reactor vehicles tested by the developer. Timing chain pins,
cam followers, rocker arms, and valve guides were affected. The developer was
convinced that the wear problems was due to the lapping action of small (0.02-
0.05 micron) metal oxide particles mixed in the engine oil, and that these small
particles come from the reactor core and find their way through the EGR line to
the lubrication system.
Severe oxidation of the reactor core 310 stainless steel material was demonstrated
in the developer's tests of two reactors which lost 0.5 pound of core weight (23
percent) after 20,000 miles of testing. The developer stated that the wear problem
could be overcome by using a material such an Inconel 601 in the reactor core.
Since oxidation of any part of the exhaust system is a potentially similar hazard,
a more complete solution would be to use an EGR gas source upstream of the thermal
reactor.
Because of these problems, the California Air Resources Board test program was
discontinued. The developer of the reactor plans to concentrate on the develop-
ment of an improved thermal reactor emission control system for new vehicles,
rather than for retrofit applications (Reference 73).
9.4.5 Maintainability
As stated above in the performance section, the EGR portion of the combined systems
did not require any maintenance. However, some deposits accumulated in the throttle
section of the carburetor which suggest that normal cleaning procedures and mileages
intervals should be followed. The EGR valve should probably be cleaned concurrently
with the carburetor. Such maintenance could be accomplished in one-half hour every
12,000 miles.
9.4.6 Driveability and Safety
The developer (Reference 73) and EPA (References 74 and 75) did not supply any
driveability data.
The combination system described here appears to have no safety problems.
9.4.7 Installation Description
Installation descriptions were not supplied by the developer.
9-25
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9.4.8 Initial and Recurring Costs
No installation costs were provided by the developer for retrofitting the
described system. Based on data in Reference 2, the additional cost for EGR
would be about $25 higher than the basic thermal reactor system cost (refer to
Table 3-20). The particulate trap cost would also have to be added.
None of the references (2, 73, 74, 75) contained any fuel consumption data.
9.4.9 Feasibility Summary
The "total control system" comprising exhaust manifold thermal reactors, exhaust
gas recirculation and traps will control hydrocarbons, carbon monoxide, nitrogen
oxides and particulate matter and appears to be technically feasible. Exhaust
manifold thermal reactors appear to be able to operate satisfactorily with leaded
fuels and it is believed, based on data from the developer, that an exhaust gas
recirculation system can be developed which also will operate satisfactorily with
leaded fuels.
Only limited cost data were available for new car applications. Retrofitting the
"total control system" appears to be economically unfeasible due to the mechanical
complexity of the entire system.
9-26
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10 - REFERENCES
-------
SECTION 10
REFERENCES
1. Environmental Protection Agency Contract No. 68-04-0038, Analysis of Effective-
ness and Costs of Retrofit Emission ControJ. Systems for Used Vehicles, 30 June
1971.
2. The Aerospace Corporation, "An Assessment of the Effects of Lead Additives in
Gasoline on Emissions Control Systems Which Might be Used to Meet the 1975-76
Motor Vehicle Emission Standards," Aerospace Report No. TOR-0172 (2787)-2,
15 November 1971.
3. 1972 Test Procedures for Vehicle Exhaust (Gasoline Fueled Light Duty Vehicles),
Subpart H of Part 1201, Chapter XII, Title 45 Code of Federal Regulations, as
published in the Federal Register, Volume 35, Number 219, Part II, 10 November
1970.
4. Device 96 Technical Characteristics Addendum to Retrofit Data Survey Question-
naire Request, 24 November 1971.
5. Thomson, John C., "Exhaust Emissions from a Passenger Car Equipped with a
(Device 96) Catalytic Converter," Report 71-16, EPA Division of Motor Vehicle
Research and Development, Air Pollution Control Office, December 1970.
6. The Clean Air Act, December 1970 (42 U.S.C. 1857).
7. California Health and Safety Code, Chapter 4, Motor Vehicle Pollution Control,
Article 5, Used Motor Vehicle Service Accreditation (refer to Volume IV,
Appendix E).
8. Thomson, John C. , "Exhaust Emissions from an Army M^-151 Equipped with a (Device
62) Catalyst," Report 71-22, EPA Motor Source Pollution Control Program, Air
Pollution Control Office, March 1971.
9. Thomson, John C., "Emission Results from a (Device 93) Catalyst Concept Applied
to a Previously Uncontrolled Engine," Report 71-26, EPA Mobile Source Pollution
Control Program, Air Pollution Control Office, April 1971.
10. Thomson, John C., "A Report on the Exhaust Emissions of an Army M-151 1/4-Ton
Truck Using an Exhaust Catalyst," Report 71-13, EPA Division of Motor Vehcile
Research and Development, December 1970.
11. Yolles, R. S., H. Wise and L. P. Berriman, "Study of Catalytic Control of
Exhaust Emissions for Otto Cycle Engines," Final Report SRI Project PSU-8028,
Stanford Research Institute, April 1970.
10-1
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12. Engelhard Industries Sales Brochures, Forms EM-8958, EM-6366, and "Engelhard
Accepts the Challenge with the PTX Catalytic Exhaust Purifier," Engelhard
Industries, A Division of Engelhard Minerals and Chemicals Corporation, New
Jersey.
13. Telecons between M. J. Webb, Olson Laboratories, Project Engineer, Contract
68-04-0038, and Herbert Morreall, Engelhard Industries, on 14 and 15 October
1971.
14. 1968 Federal Test Procedure, The Federal Register, Volume 31, Number 61, 30
March 1966.
15. 1970 Federal Test Procedure, The Federal Register, Volume 33, Number 108, Part
II, 4 June 1968.
16. EPA Interim Constant-Volume-Sampling Test Procedure Based on Nine Cycles of
the Cold-Start 1970 Federal 7-Mode Test Procedure (Telecon 25 April 1972
from W. R. Hougland, EPA Project 68-04-0038 Documentation Task Leader, to
Ralph Stahlman, EPA Office of Air Programs, Division of Emission Control
Technology, Test Branch).
17. Effectiveness of Short Emission Test in Reducing Emissions through Maintenance,
Contract 68-01-0410, Performed for the Environmental Protection Agency by Olson
Laboratories, Inc.
18. Vehicle Emission Test, 1967 Chevrolet, With and Without Device 308 Installed,
Arizona State Department of Health, Division of Air Pollution Control Test Re-
port, dated 11 November 1971.
19. Letter dated 20 August 1970 from Ethyl Corporation Research and Development
Department (Research Laboratories, 1600 West Eight Mile Road, Ferndale, Mich-
igan 48220) to Device 425 Developer, with Exhaust Emission Test Report attached.
20. Report of Panel on Automotive Fuels and Air Pollution, D. V. Ragone, Chairman,
to the Commerce Technical Advisory Board, U.S. Department of Commerce, March
1971.
21. Letter dated 3 June 1971 from Ethyl Corporation Research and Development
Department (Research Laboratories, 1600 West Eight Mile Road, Ferndale, Mich-
igan 48220) to Device 164 Developer, with Exhaust Emission Test Report attached.
22. Verrelli, Leonard D., "Exhaust Emissions from a Passenger Car Equipped with the
(Device 322) Smog Suppressor," Report 71-9, HEW/NAPCA Division of Motor Vehicle
Research and Development, October 1970.
23. Nebel, G. J. and R. W. Bishop, "Catalytic Oxidation of Automobile Exhaust Gases,"
SAE Paper 29-K, January 1959.
24. Taylor, C. Fayette and Edward S. Taylor, "The Internal Combustion Engine,"
International Textbook Company, April 1950.
25. Handbook for Installation and Repair Stations (Official Motor Vehicle Pollution
Control Device Installation and Inspection Station), Document HPH 82.1, Depart-
ment of California Highway Patrol, April 1971.
10-2
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26. Genslak, Stanley L., "Evaluation of Gaseous Fuels for Automobiles," SAE Paper
720125, January 1972.
27. Environmental Protection Agency Exhaust Emission Standards and Test Procedures
(1973-74 Model-Year Vehicles), Federal Register Volume 36, No. 128, Part II,
2 July 1971.
28. "Reduction of Air Pollution by the, Use of Natural Gas or Liquified Petroleum
Gas Fuels for Motor Vehicles," State of California Air Resources Road, 18
March 1970.
29. "Propane to Power a Police Fleet," Form No. BPN 2-70J Reprinted from Butane-
Propane News, published by Impco Division of A. J. Industries, Inc., Cerritos,
California 90701.
30. "Emission Reduction Using Gaseous Fuels for Vehicular Propulsion," Final Report
on Contract No. 70-69 for Environmental Protection Agency, Air Pollution Con-
trol Office, by the Institute of Gas Technology, Chicago, Illinois, June 1971.
31. State of California Air Resources Board Resolution 69-8, 15 January 1969.
32. State of California Air Resources Board Resolutions 70-9/A/B/C/D/E/F, 28 Janu-
ary through 21 July 1971.
33. Telecons between Truman Parkinson, Device 52 Representative, and W. R. Hougland,
EPA Project 68-04-0038 Documentation Task Leader, 3, 7, and 8 February 1972.
34. Telecon between W. Engle, Petrolane Gas Service Center, Orange County, Fountain
Valley, California, and W. R. Hougland, EPA Project 68-04-0038 Documentation
Task Leader, 3 February 1972.
35. Schematic Diagram for (Device 52) LP-Gas Operation, Form No. SLP-71, issued by
Device 52 Manufacturer.
36. Schematic Diagram for (Device 52) LP-Gas and Gasoline Dual-Fuel Operation, Form
No. LPG G-71, issued by Device 52 Manufacturer.
37. Carburetion Trouble Shooting, Form 243, issued by Device 52 Manufacturer.
38. Caggiano, Michael A., "Emissions from Two LPG Powered Vehicles," HEW/NAPCA Divi-
sion of Motor Vehicle Pollution Control, February 1970.
39. Gompf, Henry L., "Exhaust Emissions from 10 GSA Rebels and 10 GSA Falcons
Equipped with LPG Conversion Kits," Report 71-10, HEW/NAPCA Division of Motor
Vehicle Research and Development, October 1970.
40. California Air Resources Board, "Emission Tests of (Device 52) Carburetion
System, Project M 191, March 1969.
41. California Air Resources Board, "California Exhaust Emission Standards and Test
Procedures for 1971 and Subsequent Model Gasoline Powered Motor Vehicles Under
6,000 Pounds Gross Vehicle Weight," 20 November 1968.
10-3
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42. "Clean Up Your Act," a reprint from the July 1971 issue of Stock Car Racing,
issued as SSR-771 (5M) by Device 52 Manufacturer.
43. Telecons between M. Miller, EPA Project 68-04-0038 Research Assistant, and
Representatives of McCoy Ford, Fullerton, California 92631, and Towne and
Country American Motors, Anaheim, California 92801, 7 February 1972.
44. Telecons between Herbert V. Hills, Device 52 Manufacturer Executive Vice Pres-
ident and W. R. Hougland, EPA Project 68-04-0038 Documentation Task Leader,
4, 8, and 9 February 1972.
45. "California Exhaust^Emission Standards and Test Procedures for Motor Vehicles
Modified to Use Liquified Petroleum Gas or Natural Gas Fuel," State of Cali-
fornia Air Resources Board, 28 November 1969.
46. Caltech Clean Air Car Project, "Gaseous Fuels Manual," California Institute of
Technology Environmental Quality Laboartory, Pasadena, California, 1 November
1971.
47. Hopkins, Howe H., "Feasibility of Utilizing Gaseous Fuels for Reducing Emis-
sions from Motor Vehicles," (Unpublished Report), EPA Division of Motor Vehicle
Research and Development, 24 November 1971.
48. American Society of Mechanical Engineers Code for Unfired Pressure Vessels,
Section 8.
49. National Board of Fire Underwriters Pamphlet No. 58, "Storage and Handling of
Gas Cylinders," National Fire Prevention Association.
50. State of California Department of Highway Patrol, Regulations for Motor Vehicles
Converted to Gaseous Fuels (Proposed), January 1972.
51. Telecon between R. ReifSchneider, Manchester Tank and Equipment Co., Lynwood,
California, and W. R. Hougland, EPA Project 68-04-0038 Documentation Task
Leader, 10 February 1971.
52. "Your Car Will Run on LPG!" Form No. RT170 issued by Device 52 Manufacturer.
53. National LP-Gas Association Letter, dated 8 February 1972, to M. Miller, Project
68-04-0038 Research Assistant, from John Hartzell, Manager, Public Information,
with enclosures.
54. U.S. Light-Duty Vehicle Population, "Automotive News," 1971 Almanac Issue,
1 July 1970 through 1 July 1971.
55. LPG Carburetor Sales, 1960-1970; Source: National Liquified Petroleum Gas Assoc-
iation and Bureau of the Census.
56. "Propane Demand Will Outrun Supply," Oil Gas Journal, page 44, 2 March 1970.
57. Ashby, Anthony H., "Exhaust Emissions from Seven LP Gas Powered Vehicles,"
Report 71-1, HEW/NAPCA Division of Motor Vehicle Research and Development,
July 1970.
10-4
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58. Telecon between Ralph Abbot, Chief Engineer, Algas Industries, Dallas, Texas,
and W. R. Hougland, EPA Project 68-04-0038 Documentation Task Leader, 14 Febru-
ary 1972.
59. Telecon between T. R. Godburn, Applications Engineer, Marvel-Schebler Division
of Borg-Warner, Decatur, Illinois, and W. R. Hougland, EPA Project 68-04-0038
Documentation Task Leader, 14 February 1972.
60. Gompf, Henry L., "Exhaust Emissions from a Passenger Car Powered by (Device
459) LPG Conversion," Report 71-8, HEW/NAPCA Division of Motor Vehicle Research
and Development, September 1970.
61. Thomson, John C., "Exhaust Emissions from a Reactor Equipped, Full-Sized Auto-
mobile Using LPG Fuel," Report 71-21, EPA Division of Emission Control Tech-
nology, Mobile Source Pollution Control Program, Air Pollution Control Office,
March 1971.
62. Ashby, Anthony H., "Emissions from the Methanol Fueled (Device 464) Gremlin,"
Report 72-4, EPA Office of Air Programs, August 1971.
63. Telecon between Ernest Lovelin, Chemist, Amsco Division of Union Oil Co., La
Mirada, California, and W. R. Hougland, EPA Project 68-04-0038 Documentation
Task Leader, 3 February 1972.
64. California Air Resources Board Resolution 70-34A, Acceptance of Device 459
Carburetor Models 3C705DTLE and 3C706DTLE for 300-CID and Over Engines of
Light-Duty Vehicles, December 1970.
65. California Air Resources Board Resolution 71-29/A/B, Acceptance of Device 466
Carburetor Model PCAMX500A for 300-CID and Over Engines of Light-Duty Vehicles,
21 July 1971.
66. "LPA Motor Fuel and You," Form No. 9653, Century Gas Equipment, Marvel-Schebler
Division, Borg-Warner, Decatus, Illinois.
67. Thomson, John C., "An Evaluation of the Exhaust Emissions from Two Vehicles
Equipped with Compressed Natural Gas Conversion Kits," Report 71-17, EPA Divi-
sion of Motor Vehicle Research and Development, Air Pollution Control Office,
December 1970.
68. "Interest in Compressed Natural Gas Carburetion Grows as Pacific Lighting's
Dual-Fuel System Gains Approval," a Gas Industries publication by Paul Lady,
Associate Publisher.
69. "Exhaust Emission Tests of (Device 466) Natural Gas Dual-Fuel Mixer, Pacific
Lighting Service Company, Los Angeles, California, September 1969.
70. "The (Device 468) Lean Reactor System," Ethyl Corporation Research Laboratories,
Detroit, Michigan, 1 July 1971.
71. Cantwell, E. N., I. T. Rosenlund, W. J. Earth, F. L. Kinnear, and S. W. Ross,
"A Progress Report on the Development of Exhaust Manifold Reactors," SAE Paper
690139, January 1969.
10-5
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72. "Today: The Elimination of Automobile Air Pollution," Document A-70135, du
Pont Petroleum Chemicals.
73. Cantwell, E. N., "A Total Exhaust Emission System," Document A-72692, Petroleum
Laboratory, E. I. du Pont de Nemours & Co. (Inc.), Wilmington, Delaware.
74. Thomson, John C., "Exhaust Emissions From a Passenger Car Equipped with a
(Device 244) Exhaust Emission Control System," HEW/NAPCA Division of Motor
Vehicle Pollution Control, May 1970.
75. Thomson, John C., "Exhaust Emissions from a Passenger Car Equipped with a
(Device 244) Exhaust Emission Control System Using 1975 Test Procedure," Re-
port 71-3, HEW/NAPCA Division of Motor Vehicle Research and Development,
August 1970.
76. Gompf, Henry L., "Exhaust Emissions from Two Passenger Vehicles Equipped with
the (Device 1)," Report 72-6, EPA Office of Air Programs, September 1971.
77. Hollabaugh, D. M., "The Effects of Water Injection on Nitrogen Oxides in Auto-
motive Exhaust Gas," Project B-l-7-2, APCA, 1966.
78. California Air Resources Board Resolution 71-72, September 1971, Amendment
71-72A, December 1971.
79. Edwards, John B. and D. Maxwell Teague, "Unraveling the Chemical Phenomena
Occurring in Spark Ignition Engines," SAE Paper 700487, May 1970.
80. Northrop in association with Olson Laboratories, Inc., "Test and Evaluation of
the (Device 10) Exhaust Emission Control Device," Report 71Y139, California
Air Resources Board Contract ARE 1902, 2 July 1971.
81. Gompf, Henry L., "Exhaust Emissions from a Passenger Car Equipped with (Device
23)," Report 71-7, HEW/NAPCA Division of Motor Vehicle Research and Development,
September 1970.
82. Thomson, John C., "Exhaust Emissions from a Passenger Car Equipped With the
(Device 95) Electronic Anti-Pollution Engine Economizer," HEW/NAPCA Division
of Motor Vehicle Research and Development, September 1970.
83. Thomson, John C., "Exhaust Emissions from a 1971 Passenger Car Equipped With
the (Device 95) Electronic Anti-Pollution Engine Economizer," Report 71-31,
EPA Bureau of Source Pollution Control, Office of Air Programs, June 1971.
84. "The Product that Saves You Money," an unnumbered, undated sales flyer issued
by Device 95 manufacturer.
85. Device 259, Summary Test Report, published by the Device 259 Developer.
86. California Air Resources Board, "Evaluation Tests of (Device 296) Exhaust
Emission Control Device," Project 205, July 1971.
87. Freeman, Max A. and Roy C. Nicholson, "Valve-Timing for Control of Oxides of
Nitrogen (NOx)," SAE Paper 720121, January 1972.
10-6
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88. Gompf, Henry L., "Exhaust Emissions from two Passenger Vehicles Equipped with
(Device 418)," Report 71-25, EPA Mobile Source Pollution Control Program Air
Pollution Control Office, 26 November 1971.
89. Thomson, John C., "Emission Results from an Automobile Using the (Device 458)
Injector," Report 72-5, EPA Office of Air Programs, September 1971.
90. Thomson, John C., "Exhaust Emissions from Controlled and Uncontrolled Vehicles
Using the (Device 462) Emission Control Device," Report 72-1, EPA Office of
Air Programs, August 1971.
91. Thomson, John C., "Exhaust Emissions on an Uncontrolled Passenger Car Using
Variable Cam Timing," Report 71-4, Division of Motor Vehicle Research and
Development, National Air Pollution Control Administration, Department of
Health, Education and Welfare, August 1970.
92. Thomson, John C., "An Evaluation of a Variable Cam Timing Technique as a Con-
trol Method for Oxides of Nitrogen," Report 71-11, Division of Motor Vehicle
Research and Development, National Air Pollution Control Administration,
Department of Health, Education and Welfare, October 1970.
93. Meadram, G. B. Kirby, "Variable Cam Timing as an Emission Control Tool," SAE
Paper 700673, January 1971.
94. Gompf, Henry L., "Evaluation of the Emission Reduction with the (Device 246)
Speed Controlled EGR System," EPA Office Mobile Source Pollution Control Pro-
gram, Office of Air Programs, October 1971.
95. Gompf, Henry L., "Exhaust Emissions from a Passenger Car Equipped with (Device
24) Heavy Duty PCV Valve," Report 71-20, EPA Division of Emission Control Tech-
nology, Air Pollution Control Office, February 1971.
96. Thomson, John C., "Exhaust Emission from Passenger Vehicles Equipped with
(Device 294) Carburetors," Report 71-15, EPA Division of Motor Vehicle Research
and Development, Air Pollution Control Office, December 1970.
97. Thomson, John C., "Exhaust Emissions from a Vehicle Equipped with the (Device
172) Modification Supplied Under Contract CPA 70-51," Report 71-14, EPA Divi-
sion of Motor Research and Development, December 1970.
98. Kopa, Richard D., "Control of Automotive Exhaust Emission by Modification of
the Carburetor System," SAE Paper 660114, January 1966.
99. Thomson, John C., "A Report on the Exhaust Emissions from a Turbocharged
Volkswagen," Draft Report, EPA Division of Emission Control Technology, Bureau
of Mobile Source Pollution Control, Office of Air Programs, May 1971.
100. Thomson, John C., "Exhaust Emissions from a Passenger Automobile Equipped with
Electronic Fuel Injection," Report 71-12, EPA Division of Motor Vehicle Re-
search and Development, December 1970.
101. Lang, Robert J., "A Well-Mixed Thermal Reactor System for Automotive Emission
Control," SAE Paper 710608, June 1971.
10-7
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102. Thomson, John C., "An Evaluation of the Emissions Characteristics of the Esso
Well-Mixed Thermal Reactor," Report 72-3, EPA Office of Air Programs, August
1971.
103. McDonagh, Allan M., Harry J. Palola, and Lynn M. Treadway, "Alternate Fuel Sys-
tems," a report to the Fort Motor Company, California State College Long Beach,
School of Engineering, Mechanical Engineering Department, 4 June 1971.
104. Dual Fuel Systems, Inc., "Installation, Operating, and Maintenance Manual,"
105. Verrelli, Leonard D., "Exhaust Emissions from a Passenger Car with Gasoline
Treated with Bycosin Fuel Additive," Report 71-24, EPA Division of Emission
Control Technology, Mobile Source Pollution Control Program, Air Pollution
Control Office, April 1971.
106. Hollabaugh, D. M., "The Effects of Water Injection on Nitrogen Oxides in Auto-
motive Exhaust Gas," Project B-l-7^-2, APCA, 1966.
107. Caggiano, Michael A, "The Effect on Exhaust Emissions of (Device 36)," HEW/NAPCA
Division of Motor Vehicle Pollution Control, June 1970.
108. "Air Quality Criteria for Carbon Monoxide," AP-62, HEW/NAPCA.
109. "Air Quality Criteria for Hydrocarbons," AP-64, HEW/NAPCA.
110. "Air Quality Criteria for Nitrogen Oxides,"
111. Jackson, Marvin W., "Effects of Some Engine Variables and Control Systems on
Composition and Reactivity of Exhaust Hydrocarbons," SAE Paper 660404, June
1966.
112. Harrison, L. C., "Techniques for Controlling the Oxides of Nitrogen," Journal
of the Air Pollution Control Association, Volume 20, No. 6, June 1970.
113. Hidy, G. M. and S. K. Friedlander, "The Nature of the Los Angeles Aerosol," a
paper published by the California Institute of Technology, Pasadena, California,
August 1970 (presented at the 2nd IUAPPA Clean Air Congress, Washington, D. C.,
December 1970).
114. Control Techniques for Carbon Monoxide, Nitrogen Oxide, and Hydrocarbon Emis-
sions from Mobile Sources, HEW/NAPCA Publication No. AP-66.
115. "California Test Procedure and Criteria for Motor Vehicle Exhaust Emission
Control," issued by the State of California Motor Vehicle Pollution Control
Board.
116. Ohigashi, S. et al, "Heat Capacity Changes Predict Nitrogen Oxides Reduction
by Exhaust Gas Recirculation," SAE Paper 71001,0.
117. Quader, Ather A., "Why Intake Charge Dilution Decreases Nitric Oxide Emission
from Spark Ignition Engines," SAE Paper 710009.
10-8
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118. Freeman, Max A. and Roy C. Nicholson, "Valve Timing for Control of Oxides of
Nitrogen (NOx)," SAE Paper 720121, January 1972.
119. Musser, G. S., J. A. Wilson, and R. G. Hyland, "Effectiveness of Exhaust Gas
Recirculation with Extended Use," SAE Paper 710013, January 1971.
120. Niepoth, G. W., G. P. Ransom, and J. H. Currie, "Exhaust Emission Control for
Used Cars," SAE Paper 710069, January 1971.
121. California Air Resources Board, "California Test Procedure and Criteria for
Motor Vehicle Crankcase Emission Control," 1 April 1966.
122. Deeter, W. F., H. D. Saigh, and 0. W. Wallin, Jr., "An Approach for Controlling
Vehicle Emission," SAE Paper 680400, May 1968.
123. Telecon between C. Mertz, Systems Engineer, Northrop Electro-Mechanical
Division, and Parts Department Manager, McCoy-Mills Ford, Fullerton, Cali-
fornia, 27 November 1971.
124. Lee, R. C. and D. B. Wimmer, "Exhaust Emission Abatement by Fuel Variations
to Produce Lean Combustion," SAE Paper 680769, 29-31 October 1968.
10-9
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11 - DEVICE INDEX
-------
SECTION 11
RETROFIT DEVICE INDEX
DEVICE
NO.
1
10
22
23
24
31
33
36
42
52
56
57
59
62
69
93
95
96
100
160
164
165
VOL. II
PARA.
4.1.1
4.2.1
4.6.1
5.2.1
7.1.1
3.2.4
4.4.1
6.3.1
4.1.2
6.1.1
4.4.2
4.1.3
9.1
3.1.3
5.1.1
3.1.4
5.2.2
3.1.1
4.5.1
7.2.1
3.4.1
9.2
PAGE
4-3
4-50
4-141
5-22
7-3
3-64
4-104
6-76
4-14
6-5
4-112
4-22
9-1
3-26
5-3
3-29
5-23
3-3
4-139
7-21
3-89
9-5
DEVICE
NO.
170
172
175
182
244
245
246
259
268
279
282
288
292
294
295
296
308
315
317
322
325
384
VOL. II
PARA.
7.1.2
4.3.1
5.1.2
6.2.1
3.2.1
4.2.2
4.2.3
5.2.3
5.2.4
6.3.2
6.2.3
4.4.3
3.1.2
4.2.4
4.4.4
5.2.5
3.3.1
7.1.3
4.4.5
3.5.1
4.1.4
4.3.4
PAGE
7-7
4-80
5-12
6-61
3-31
4-58
4-67
5-25
5-32
6-78
6-67
4-117
3-19
4-79
4-123
5-36
3-73
7-15
4-132
3-95
4-30
4-97
DEVICE
NO.
401
408
418
425
427
430
433
440
457
458
459
460
461
462
463
464
465
466
467
468
469
VOL. II
PARA.
4.1.5
9.3
4.1.6
3.3.2
7.2.2
4.3.2
4.1.4
4.3.3
6.2.4
4.1.7
6.1.3
6.1.6
6.1.4
4.1.8
3.2.2
6.1.5
6.2.2
6.1.2
8.1
3.2.3
9.4
PAGE
4-39
9-15
4-43
3-79
7-27
4-86
4-30
4-91
6-73
4-45
6-35
6-47
6-40
4-46
3-51
6-43
6-66
6-31
8-3
3-58
9-21
11-1
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