EMISSIONS  CONTROL
OF
ENGINE  SYSTEMS
            CONSILTANT REPORT TO THE:
         Committee on Motor Vehicle Emissions
         Commission on Soeioleehnical Systems
                               •
             National Research Council
                SEPTEMBER 1974
       l.S. ENVIRONMENTAL PROTECTION AGENCY
          Office of Air and Waste Management
       OH ice oi Mobile Source Air Pollution Control

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                         CONSULTANT REPORT




                              to the




               Committee on Motor Vehicle Emissions




               Commission on Sociotechnical Systems




                     National Research Council




                                on




               EMISSIONS CONIROL OF ENGINE SYSTEMS
PREPARED BY:




           James E. A. John, Chairman, Engine Systems




           Naeirn A. Henein




           Ernest M. Jost




           Henry K. Newhall




           David Wulfhorst




           John W. Bjerklie, Chairman, Alternatives




           William J, McLean




           Charles Tobias




           David Gordon Wilson
                         Washington, D,C.




                          September 1974

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                                  NOTICE
       This consultant report was prepared by a Panel of Consultants at
the request of the Committee on Motor Vehicle Emissions of the National
Academy of Sciences.  Any opinions or conclusions in this consultant re-
port are those of the Panel members and do not necessarily reflect those
of the Committee or of the National Academy of Sciences.

       This consultant report has not gone through the Academy review
procedure.  It has been reviewed by the Committee on Motor Vehicle Emis-
sions only for its suitability as a partial basis for the report by the
Committee.

       The findings of the Committee on Motor Vehicle Emissions, based
in part upon material in this consultant report but not solely dependent
upon it, are found only in the Report by the Committee on Motor Vehicle
Emissions of November 1974.

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                                  PREFACE

       The National Academy of Sciences, through its Committee on Motor
fehicle Emissions (CMVE), initiated a study of automobile emissions-
control technologies at the request of the United States Congress and
the Environmental Protection Agency (EPA) in October 1973,  To help
carry out its work, the CMVE engaged panels of consultants to collect
information and to prepare consultant reports on various facets of mo-
tor vehicle emissions control.  This Consultant Report on Emissions
Control of _Engine Systems is one of five consultant reports prepared
and submitted to the Committee in connection with the Rejxnrt by the
Cpnroittee on Motor Vehicle Emissions of November 1974,  The other con-
sultant reports are:
              An Evaluation of Catalytic Converters for
              Control of Automobile Exhaust Pollutants,
              September 1974
              Emissions and Fuel Economy Test Methods and
              Procedures, September 1974
              Field Performance of Emissions-Controlled
              Automobiles, November 1974
              Mamifacturability and Costs of Proposed Low-
              Emissions Automotive Engine Systems, November
              1974
These five consultant reports are NOT reports of the National Academy
of Sciences or its Committee on Motor Vehicle Emissions.  They have
been developed for the purpose of providing a partial basis for the
report by the Committee as described more fully in the cover NOTICE.

                         ACKNOWLEDGEMENTS

        The authors would like to thank Drs, Robert F. Sawyer and
Nicholas P, Cernansky for their contributions to this consultant
report.

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                                  CONTENTS


 Conclusions	•	     1

 1.   Introduction	»..     3

 2.   Modifications to Conventional Reciprocating Spark-Ignition
     (S.I.) Engines	     5

 3.   Conventional Spark-Ignition Engine with Oxidation Catalyst—
     1975 Standards	    10

 4.   Potential of Conventional Engines with Oxidation Catalysts...    13

 5.   Air/Fuel Mixture Preparation	    18

 6.   Lean Burn Sys terns	    62

 7.   Dual Catalyst Systems	    67

 8.   Three-Way Catalys t with Feedback	,	    80

 9.   Rotary Engines	    90

10.   Stratified-Charge Engines	   100

11.   Diesel Engines	   137

12.   Alternative Power Plants for Automobiles	   179

13.   Alternative Fuels	   214

References	   239

Appendices

A.  Organizations Contacted by Members of the Panel of Consultants
    on Engine Systems	   256

B.  Organizations Contacted by Members of the Panel of Consultants
    on Al ternatives	   259
                                    IV

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                                   TABLES




Table Mo.                                                     Page No,

2.1
2.2
4.1
4.2
4.2
5.1
5.2
5.3
5.4
6.1
6.2
7.1
7.2a
7.2b
7.3
7.4
7.5
8.1
Summarization of the Work of the Panel on
Interns! Comb us tion Engines .....................
Federal Exhaus t -Emission Standards 	
Effect of Engine Modifications on Emissions. ....
Results of 1975 California Certification 	
Exhaust Emission Test Summary California Division
of Highways Unclerf loor Converter Fleet. 	
"in Service" Fuel Economy Summary California
Division of Highways Underfloor Converter Fleet.
Test Results of a 1973 Dodge Monaco. 	 	 	
Cylinder- to-Cylinder Distribution Spreads 	
Comparison of Air/Fuel Ratio Distribution with
and without Vapipe - 1.8 Litre 	
Evaluation of a Carburetor with Ultrasonic Fuel
Dispersion Used on a Plymouth Duster. ...........
1974 Dodge, 360 CID, 4,500 Ibs (Ethyl tests) 	
Results with the Dresserator on the 1975 FTP,...
Experimental Results - Dual Catalyst System.....
Prototype 1977 Dual Catalyst System Performance
350 CID, 5,000 lb} EGR, Air, '75 FTP Low Mileage
18 Car Fleet 1977 Dual Catalyst System Performance
1977 Dual Catalyst - Closed-Loop System Performance
Results of GEM 68 System
Questor System on 1971, 400 CID Pontiac Catalina
Results of Three-Way Catalyst with EFI and
Feedback 	
2
6
7
14
15
16
28
37
40
41
62
65
68
70
71
73
76
78
82
                                    V

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Table No.                                                       Page No.

  8.2        Data on a Vega with Three-Way Catalyst,  EFI
             and Feedback	        85

             Comparison of Various Control Schemes (1.9 L
             Engine) All Cars Equipped with L-jetronic	        86

             Results of Three-Way Catalyst with MFI	        87

             GM Results with Advanced Design Carburetors,
             Feedback and Three-Way Catalyst	        88
   9.1       Exhaust Emissions of the 1974 Mazda with Rich
             Thermal Reactor	         91

   9.2       Typical Deterioration Factors of Thermal
             Reactor-Equipped Rotary Engines „	         94

   9.3       Emissions Summary	         95

   9.4       Rotary with Lean Reactor	         96

   9.5       Emission and Fuel Consumption Characteristics
             of an Experimental Open-Chamber  Stratified-
             Charge Rotary Engine	         97

  10.1       Emissions and Fuel Economy of Turbocharged
             TCCS Engine-Powered Vehicle                          116

  10.2       Fuel Specifications for TCCS Emissions Tests,.        117

  10.3       Honda Compound Vortex-Controlled Combustion-
             Powered Vehicle Emissions	        124

  10.4       Emissions and Fuel Economy for Chevrolet Impala
             Stratified-Charge Engine Conversion                  125

  10.5       Single-Cylinder Low Emissions Engine Tests....        133

  10.6       Volkswagen Large-Volume Prechamber Engine
             Emis s ions	        135

  11.1       Mass Emissions and Fuel Economy  from LDV
             Diesel Engines - 1975 FTP                            138
                                   VI

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Table Mo.                                                         Page No_,
11
11
11
11
11
11
11
11
1 7
1 ?
12
11
1 1
13
13
13
13
,2
.3
.4
,5
,6
,7
,8
,9
.1
.2
.3
.la
. Ib
.2
,3
,4
.5
Effect of Injection Timing on Emissions
from Perkins 154 Engine in Ford Zephyr
Car (CVS Cycle) 	
Aldehydes and Ammonia Emissions from Different
Types of Cars 	
Comparison Between Opel Diesel and Gasoline
Cars 	 	 . 	 , 	 ..
Fuel Economy in Taxi Application 	 	 . .
Comparison Between Diesel and Gasoline Fuels..
Initial and Maintenance Costs and Performance
of Mercedes 1975 Cars 	 	 , 	 	 	
Comparison Between Exterior arid Interior
Noise Levels of Diesel- and Gasoline-Powered
Cars 	 	 	 	 	 	 	 , 	
Comparison of Odor from Diesel- and Gasoline-
Powered Cars 	 , 	
Steam Engine Characteristics 	 	
Stirling Engine Description 	
Batteries for Electrically Driven Vehicles.,..
Cos t of Alternative Fuels 	
Cost of Alternative Fuels 	
Physical Properties of Iso-octane and Methanol
Test Data for 15% Methanol -Gasoline Blend 	
Federal Test Procedure Emissions with Hydrogen
Supplemented Fuels 	 , . , 	 , 	 , .
Effect of Vareb-10 on Cold-Start Emissions....
145
153
158
161
161
163
171
175
188
193a
204
218
219
227
233
231!
237
                                   VLl,

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                                  FIGURES
Figure No.
   5.1            The Relationship of Typical  Engine Emissions
                  and Performance to Air /Fuel  Ratio ...........     19

   5.2            Air/Fuel  Ratio Control ......................     21

   5.3            Idle Speed Circuit ..........................     22

   5.4            Fuel Metering Curve... ......................     23

   5.5            Air/Fuel  Ratio Distribution .................     25

   5.6            Variable  Venturi Carburetor .................     27

   5.7            Fuel Droplet Size Distribution ..............     29

   5.8            Sonic Carburetor Principle ..................     31

   5.9            Ford Motor Co. Estimate of Induction System
                  Mixture Quality Trends under Hot Operating
                  Conditions ..................................     32

   5.10           Ford Motor Co. Estimate o£ Induction  System
                  Mixture Quality Trends under Cold-Start and
                  Driving Conditions ..........................     33

   5.11           Ethyl Corporation's Rectangular Hot Box Man-
                  ifold for a 360 CID Plymouth ................     36

   5.12           Location  of Vapipe. . . . . .....................     39

   5.13           Ultrasonic Carburetor... ....................     42

   5.14           Electronic Fuel Injection. . .................     44

   5.15           Air Mass  Sensor ............... . .............     47

   5.16           K- jetronic System ...........................     50

   5.17           (No title) ..................................     52

   5 . IS           Oxygen Sensor ...............................     56

   5.19           Sensor Characteristic .......................     58
                                 VL1L

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f_igure Ho.                                                     Page.

  5.20            Sensor Output	    59

  5.21            Optimizer Control	    60

  7.1             Durability Data	    68

  7.2             AMA Durability Test - Oxidizing and Reducing
                  Catalyst	    69

  7.3             Effect of Getter  on Inlet CO and 02	    74

  7.4             Typical Net NOX Conversion	..    75

  8.1             Conversion Efficiency of a Three-Constituent
                  Catalyst.	    81

  8.2             4-Cylinder Engine, 1.9 Liter,, L-jectronic. ..    83

  8.3             Catalyst Durability.	    84

  9.1             IIC Conversion Efficiency Requirements.......    92

  9.2             Comparison of NOX and Fuel Consumption	    98

 10.1             Ford Proco Sys tern.	   106

 10.2             Ford Proco Engine Fuel Economy and Emissions   107

 10.3             Texaco TCCS Engine	   110

 10.4             Texaco Controlled Combustion System	   Ill

 10.5             Texaco TCCS-Powercd Cricket Vehicle.	   113

 10.6             Turbocharged Texaco TCCS M151 Vehicle.......   114

 10,7             3-Valve Prechatnber Engine Concept	   119

 10.8             Honda CVCC Engine..	   122

 10.9             Fuel Economy  Versus HC Emissions for 3-
                  Valve Prechamber Engines	   126

 10.10            Fuel Economy Versus NOX Emissions for Honda
                  CVCC-Powered Vehicles	   128

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Figure No.                                                        Page No,

  10.11            Ford Divided Chamber .................. . ......   131

  10.12            Comparison of Conventional and Divided
                   Combustion Chamber NOx Emissions . ............   132
  10.13            400 CID Large Volume Precharaber Engine.. .....  134

  11.1             Emissions from Dies el -Powered Cars
                   (1975 FTP) ...................................  139

  11.2             Effect of EGR on the Emissions from a
                   Mercedes Diesel Engine .......................  141

  11.3             Effect of EGR on Opel Rekord Diesel Car
                   (1975 FTP) ...................................  143

  11.4             Effect of Injection Timing on Emissions
                   (1975 FTP) ................ . ..................  144

  11.5             Airborne Particulates Emitted from Diesel-
                   and Gasoline-Powered Cars .................. . .  147

  11.6             Benzo(a)Pyrine Emissions from Different
                   Automotive Engines According to 1975 FTP-
                   Cold Start ...................................  149

  11.7             Benzo (a)Pyrine Emissions from Different
                   Automotive Engines at 60 mph Steady Running
                   Conditions .................. . ................  150

  11.8             Sulfur Compounds Emissions from Different
                   Cars .................................. . ......  151

  11.9             HCHO Emissions for the Modified Federal Cycle
                   Cold S tart (MFCCS ) ...........................  154

  11.10            HCHO for 60 niph Steady Running Conditions ____  155

  11.11            Comparison of Fuel Economy at Road Load for
                   Mercedes Diesel and Gasoline Cars,, ..........  157

  11.12            Comparison of mpg for Different Cars under
                   Steady-State Conditions ......................  159

  11.13            Comparison of mpg for Different Cars under
                   City- Suburban and Average Driving Condi-
                   tions .................. . .....................
                                     x

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Figure Mo.                                                      Page Ko.

  11.14            Comparative Driveability of Diesel-
                   Powered and Other Cars	   166

  11.15            Exterior Noise Levels from Different Cars...   167

  11.16            Exterior Noise Levels from Different Cars.,.   169

  11.1?            Comparison of Exterior Noise Levels for 2.2
                   Liter Mercedes Gasoline and Diesel Cars	   170

  11.18            Interior Noise Levels from Different Cars...   173

  12.1             Rear View of VW with Carter Steam Engine
                   Mounted; The Prime Mover Showing the 4
                   Cy 1 inder		    189

  12.1             The Boiler-Burner Assembly	    190

  12.2             Flowchart	    192

  12.3             Fuel Economy-Alternative Engines	    213

  13.1             U.S. Petroleum Supply and Demand,	    217

  13.2             Emissions Data for Alcohol-Gasoline Blends
                   (1975 FTP)	    232

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                               CONCLUSIONS

1.   From the viewpoint of fuel economy, at least on an urban-type
    driving cycle, the diesel and stratified-eharge engines appear
    most attractive.  Potential problem areas for these engines that
    must be resolved before large-scale introduction include smoke
    and participates (and possible adverse health effects), odor,
    noise and a lower performance than a conventional spark-ignition
    (S.I.) engine due to lower power-to-weight ratio (especially
    with the diesel).

2.   The three-way catalyst system with feedback control appears to
    offer benefits as far as maintainability and driveability are
    concerned, with only slight loss of fuel economy due to emissions
    control.  The dual-catalyst (Gould) system provides a tolerable
    interim approach until the three-way catalyst, feedback system is
    ready for producticn.

3,   Regarding standards for 1978, lowering of NOX emissions levels
    from 1.0 to 0,4 g/mi appears to exact a penalty in fuel
    consumption of up to 35% by excluding the diesel engine.  Possible
    benefits to health should be weighed against this cost.

4.   There are no alternative, non-internal combustion engines that
    could be available in mass production for standard-size
    automobiles before the 1980's.

5.   The accompanying table summarizing the work of the Panel of
    Consultants on Internal Combustion Engines presents emissions
    levels achievable in certification for various systems, as well
    as fuel economy penalty (or advantage) due to emissions controls
    as measured on the Federal CVS/CH driving cycle.  Projected
    dates of availability for mass production of each system are also
    given in the table.

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Emissions
Levels                       System

0,41-3,4-2.0   Oxidation catalyst and exhaust gas
               reeireulation and engine modifications

               Lean burn engine

               Diesel

               Stratified charge -
               small volume prechamber with reactor

               Stratified charge -
               direct fuel-injected with catalyst

               Wankel with lean reactor
   Fuel Economy
      Penalty       Availability for
(relative to 1967)  Mass production
           5%


           57.

   -(251-40%)


      01-10%


   •(257«,-40%)

      5%-10%
   1976


   1977

   Now


   Now


   1980

   1976
0,41-3,4-1,0   Diesel and exhaust gas  recirculation

               Dual catalyst (e.g.,  Gould)  system

               Three-way catalyst and  feedback

               Stratified charge -
               small volume prechamber with reactor

               Stratified charge -
               direct fuel-injected  with catalyst

               Wankel with lean reactor and exhaust
               gas recirculation
    <20%-35%)

      5H-1Q7.

      0%-5%


     lQ%-2ffi


    (15%-20%)


          20%
   1976

   1977

1978-80


   Now


   1980


   1976
0,41-3.4-.4    Dual catalyst (e.g., Gould)  system

               Three-way catalyst and feedback

               Stratified charge -
               small volume prechamber with reactor

               Stratified charge -
               direct fuel-Injected with catalyst
      Q%-5%


     25%-30%
   1977

1978-80


   Now


   1980

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                         1.  INTRODUCTION
       The Consultant Report on Emissions Control of Engine Systems
represents the findings of the Panel on Internal Combustion Engines
and the Panel on Alternative Engines,  The first Panel was charged
with evaluating the potential of conventional, spark-ignition
internal-combustion engines and other internal-combustion engines,
such as the rotary., diesel and stratified-charge engines, for meeting
strict levels of oxides of nitrogen  (NO ) control in conjunction
                                       JC
with specified levels of unburned hydrocarbons (HC) and carbon
monoxide (CO).  The second Panel was charged with assessing the
potential of alternative, more advanced automotive engines, such as
the gas turbine, Stirling, and Rankine power plants, for meeting
similarly strict levels of emissions control.  Primary consideration
was to be given to cost, in terms of fuel consumption, associated
with the achievement of various NO   levels by the different engine
                                  X
systems.  The Panels were to be concerned with emissions levels
attainable in certification with vehicles tested according to the
1975 Federal Test Procedure (FTP),   Durability of the engine - and
emissions-control systems for 50,000 miles was of importance, with
mileage accumulation according to the certification test procedure.
Likewise, fuel economy was to be evaluated on vehilces being driven
on the FTP.  Other Consultant Reports to the CMVE are to deal with
performance in customer use, alternate testing procedures, catalytic
converters, and the manufacturability and costs of low-emissions
engine systems.
       The CMVE, for the purpose of  this study, is interested in
engines and systems that could be available in mass production by
the late 1970's and early 1980's.
       For the 1975 model year, well over 9570 of the new vehicles
sold in the United States will continue to be powered by conventional
reciprocating spark-ignition engines with add-on devices to control
emissions to the required levels.  Small numbers of rotary,

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stratified-charge and diesel-powered vehicles will also be available.
Due to manufacturing lead times and constraints in the tooling
industry, it is clear that the conventional engine will continue
Co dominate the market, at least up to the 1980"3, in spite of
potential advantages that one or the other alternatives may have  in
terms of emissions, economy, maintainability, performance or cost.
For this reason, the first sections of this report will deal with
the conventional engine, and the various add-on devices and engine
modifications that have the potential for meeting increasingly
stringent NO  levels.  "Later sections of the report will cover, in
depth, the rotary, stratified-charge and diesel internal combustion
engines.
       The current status of development of alternative, non-internal-
combustion engines is such that at least another generation of
development will be required before any of these will have reached
the stage of being considered a suitable prototype for manufacture.
Whereas several such engines have been run in automobiles; for
example, the gas turbine,  Stirling, steam and electric engines,
several major developments are necessary before these power plants
would be ready for mass production.  The Panel of Consultants estimates
that 1982 is the earliest one of the alternate engines, the gas
turbine, would be ready for limited production, and even then only if
several technological advances are achieved.   For this reason, the
sections of this report dealing with alternative engines must be
considered of less direct relevance to the goals of the CMVE in
their study as compared to the sections on the internal-combustion
engine.

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          2.  MODIFICATIONS TO CONVENTIONAL RECIPROCATING
                   SPARK-IGNITION  (S.I.) ENGINES

        Up  to the 1974 model year, auto manufacturers  for  the most part
have met the exhaust-emissions standards by means of modifications to
the conventional engine.  As a reference,  the federal  and  California
standards that have been achieved  in certification, all converted to the
1975 FTP, as well as  future emissions standards, are given in Table 2.1.
Changes to  achieve the specific standards, up to model year  1974, have
included alterations  in spark  Liming, reduction in compression ratio (CR),
use of leaner air/fuel (A/F) ratios, shorter choke times,  improvements
in carburetion, exhaust-gas recirculation  (ECR), use of air  pumps and air
injection to promote  exhaust reactions, and inlet air  preheating.  The
primary effects of these modifications on  exhaust emissions  are summarized
in Table 2.2 below.
        Such techniques have been  successful in achieving  reductions in
exhaust emissions from those of an uncontrolled 1967 vehicle of approxi-
mately 8070  in hydrocarbons., 707, in carbon monoxide and 50% in oxides of
nitrogen.   Accompanying these reductions in emissions has  been an increa;. j
of vehicle  fuel consumption.  Factors such as spark retard,  reduction of
compression ratio and exhaust-gas  recirculation have tended  to reduce
engine efficiency and, hence, degrade fuel economy.  Alternately, reduc-
tions of choke times  and improvements in carburetion have  a beneficial
effect on fuel economy.
        The overall fuel economy degradation on a sales-weighted
average due to emissions controls, from 1967 to 1973 or 1974, is between
       123 -'•'
1070-15% f '  based on the vehicles being tested on the urban federal
driving cycle.   Greater losses have been felt in larger cars, only small
decreases or even benefits in smaller cars.
        There are several reasons why small cars have not  shown the
same increase of fuel consumption as standard or large-size cars.
First, with the lower exhaust flows of smaller cars,  the mass emissions
of NO  and  CO of uncontrolled small cars (less than 3,000  Ibs) were
     x                                                  4
less than those of larger cars (greater than 4,000 Ibs).   This
^'References are listed at the end of the report (page 139)
                                    5

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Federal

1967 (Precontrol)
1968
1970
1972
1973,1974
1975,1976
1977
1978
6
TABLE

2.1


Exhaust -Emission Standards
HC(g/mi)
12
6.2
4.1
3
3
1.5
0.41
0.41
C0(g/mi)
79
51
34
28
28
15
3.4
3.4
NO (g/mi)
6
NR*
NR
NR
3.1
3.1
2.0
0,4
--Not required California Exhaust-Emission Standards
1972
1974
1975,1976
2.9
2.9
0.9
28
28
9
3.1
2.0
2.0

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                          7

                      TABLE  2.2


       Effect  of  Engine Modifications on Emissions
                    HC          CO         NOX

Spark Retard       Reduce     	         Reduce

Reduce CR          Reduce     	         Reduce

Lean A/F           Reduce     Reduce       Increase  (then decrease if
                                                    beyond A/F = 16)
EGR                Increase   -•	         Reduce

Air Injection      Reduce     Reduce	

Shorter Choke
Time               Reduce     Reduce       	

Air Preheat        Decrease   	         Increase

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has meant that less EGR, for example, has been necessary to reduce
NO  to required Levels.
  x
       Further^ pre-controlled small cars typically ran with richer
calibrations than standard or large cars.  Greater improvements were
then realized with leaning out the carburetion.  Finally, fuel-
metering technology for larger cars has been superior to that of -small
cars.  The imposition of emissions controls has required large
improvements in fuel metering for small cars, some manufacturers
going to mechanical or electronic fuel injection.  Thus, these factors
have all tended to improve economy of small cars, canceling out losses
due to other engine modifications to achieve emissions control.
       The most important factors that cause increased fuel
consumption due to emissions control have been spark retard, decrease
of compression ratio, and EGR.  Reduction of one compression ratio,
for example from 9:1 to 8:1, has the effect of increasing fuel
consumption by 3%-5%.  A comparable fuel economy penalty has been
incurred with the use of spark retard to achieve HC and NO  control.
                                                          x
Further, the use of  off/on EGR to achieve NO  levels of 3,1 g/mi
called for in 1973 and 1974 models has brought about an approximate
5%-6% decrease of fuel economy.
       It is important to realize that exhaust emissions are
influenced by many engine variables; for good economy and low
emissions, control systems must be optimized.  For example, running
lean provides benefits in fuel economy, but may result in higher 10
                                                                   A
emissions, necessitating the use of EGR.  The use of EGR, requiring
mixture enrichment to retain driveability, also permits an increase
of spark advance, which may recover some of the fuel economy
degradation caused by using EGR.
       In general, engine modifications, such as spark retard and
EGR or the addition of an air pump, adopted to lower emissions from
1974 levels to those of 1975 models for the 49 states or even

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California, have the effect of degrading both fuel economy and
driveability.  Thus, whereas manufacturers are certifying
vehicles with only engine modifications for production at 1975 federal
levels or at 1975 California levels, such vehicles incur a fuel
economy penalty of 57.-10% relative  to 1974 vehicles.  For the most
part, such systems are backup to  their primary, first-choice system
which features the use of an oxidizing catalytic converter.

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               3.  CONVENTIONAL SPAIR-IGNITION ENGINE WITH
                   OXIDATION CATALYST - 1975 STANDARDS

       A very large percentage of 1975 models sold in the United
States, both domestic and foreign made, will feature the use of an
oxidation catalyst to clean up the exhaust hydrocarbons and
carbon monoxide.  Several different configurations of catalyst and
system will be used.  For example, General Motors will generally
employ an under-floor pelletized catalyst bed, whereas Ford will use
a monolith located nearer to the engine.  Ford will use an air putnp
on all catalyst-equipped cars; General Motors and Chrysler will use
air pumps in California cars, but only on a small number of 49-state
cars.  Whereas Chrysler and Ford will use about the same carburetion
as 1974, General Motors will run.  at about A/F ratio = 16, leaner
than 1974.  All catalyst-equipped cars will use low lead (91 RON)
fuel (.05 g/gal) to prevent catalyst poisoning.  Nineteen seventy-five
emissions-control systems will also feature improved start-up
procedures to permit rapid fuel evaporation, high energy breakerless
electronic ignition to provide more reliable ignition, and EGR to
control NO .
          x
       At present, it appears that virtually all 1975 models equipped
with oxidising catalytic converters will be certified for production.
Catalyst durability is such that no American-made models and only some
European models will require catalyst changes in 50,000 miles.  With
lead-free fuel and breakerless ignition, there appears to be very
little deterioration in engine emissions for 50,000 miles.  The chief
difficulty is deterioration in HC control with the catalytic converter.
Whereas HC conversion efficiencies are well over 95% at low mileage,
they deteriorate to 60%-70% at 50,000 miles.
       Fuel-economy gains are to be experienced with the use of
oxidation catalysts.   To some extent, the car can now be tuned for
optimum economy, with the catalyst cleaning up the resultant HC and CO
emissions, rather than tuning for minimum emissions and losing
economy.  Chief economy gains are to be realized with elimination
                                    10

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                                    11
of some of the spark retard used in previous model years to control
HC.  The limitation on the amount of spark advance with catalytic
systems is not resultant HC levels but  the octane rating of the fuel
used and the resultant problem of knock.  With more spark advance,
proportional EGR systems more closely tailored to the engine
requirements, better cold-start performance and, In some cases,
leaner-carburetion, large economy improvements are possible.  On the
basis of data taken from durability certification cars, General
Motors  reports the following improvements in fuel economy, comparing
1975 vs 1974 49-state cars in the federal test procedure:

                     Including Mix Change         + 19.8%
                     Eliminating Mix Change*      + 21.1%
       -'Assumes 1975 mix (75% large cars) for 1974 production, where
        actual 1974 production was 80%  large cars,

A  comparison of fuel economy for GM California 1975 cars vs 49-state
cars shows an approximate 5% degradation in fuel economy  sales-
veightcd miles per gallon (SWMPG) for the California cars, due
primarily  to the use of the air pump and increased EGR in California
cars.  Again, results are from certification tests run on the FTP,
       Somewhat lesser fuel economy improvements in certification
have been  reported by the other American and foreign manufacturers.
For example, Chrysler and Ford anticipate a 5%, improvement in economy
over 1974  vehicles.  It must be remembered that the above figures
represent  comparisons between different model years of the same
manufacturers.  Comparisons of the SWMPG of American manufacturers
for 1974 models showed the following:
                          GM             10.29
                          Ford           11.63
                          Chrysler       11.10

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                                    12
       The use of catalytic converters on small cars has not resulted
in a fuel economy improvement, primarily because such cars did not
suffer the penalty due to engine modifications of the large cars,
Therefore,, foreign manufacturers report fuel economy for 1975 vehicles
roughly equivalent to that of 1974 models.
       It is significant to note that with the use of the catalytic
converter, most, if not all, of the 107« to 15% fuel economy penalty
attributed to emissions controls has been recovered.

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  4.  POTENTIAL OF CONVENTIONAL ENGINES WITH OXIDATION CATALYSTS
       In examining the potential of conventional systems for meeting
the current 1977 standards of 0,41 g/mi HC, 3,4 g/mi CO and 2,0 g/mi
NO  , it is of interest to look first at results achieved by 1975
California certification cars, tuned to meet levels of 0,9 g/mi HC,
9.0 g/mi CO and 2.0 g/mi NO  .  Table 4,1 shows data from all the
vehicles that have, at this  date, been made available to the Panel of
Consultants and have completed California certification.  The quoted
emissions values include 50,,000-mile deterioration factors, applied
                                             Q
in  the required certification test procedure.
       Caution must be exercised in drawing conclusions from Table 4.1
manufacturers must aim at targets well below the standards to ensure
with some degree of confidence that a satisfactory mix of vehicles
will pass certification and  be available to the market.  Nevertheless,
these vehicles were not tuned to meet 1977 Levels, but rather the
higher California 1975 levels, so significant reduction in emissions
are possible  (below those of Table 4.1),
       Very little data are  available on systems tuned to meet 1977
levels.  General Motors has  had two fleets of Oldsmobiles in service
with the California Highway  Department.  Both fleets were tuned to
meet 1977 levels, and equipped with oxidation catalysts, one fleet
with air pumps, one without.   Results are shown in Table 4,2.   Mileage
accumulation for these data were not according to the AMA durability
schedule of the FTP.
       The data shown in the above mentioned tables provide
convincing evidence that 1977 levels can be achieved by model  year
1977.   One method of achieving the required reductions in emissions
from California 1975 certification would be via engine modifications,
such as spark retard,  with the loss of fuel economy.   However,
improvements are available which would not necessarily increase fuel
consumption over that of  a 1975  California car.
                                  13

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Manufacturer
1.

2.

3.
4.
5.
6.
7-
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
GM

GM

GM
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
AMC
14
TABLE 4,1
Results of 1975 California
Vehicle
Vega, 2,750# I.W., 140 CID
Automatic
Cutlass, 4,500#, 350 CID,
Automatic
Delta 88, 5,000#, 350 CID
Hornet 232 A, 3,500#
Hornet 258 A, 3,500*
Homet 232 M, 3,500#
Gremlin 232 A, 3 ,000*
Pacer 258 M5 3,5QQ#
Matador 304 A, 4,500#
Gremlin 304 M, 3,500#
Hornet 304 M, 3,500#
Matador 304 A, 4,500#
Matador 2V-360 A, 4,500#
Matador 2V-360 A, 4,500??
Matador 2V-360 A, 4,500#
Matador 4V-360 A3 4,500#
Matador 4V-401 A, 4,500#
Certification,
HC
0.4

0.4

0.7
0.28
0.18
0.46
0.22
0.26
0.46
0.49
0.64
0.23
0.51
0.36
0.45
0.42
0.51
CO
6.8

2.3

6.7
7.5
5.9
7.3
6.2
6,3
3.7
6.3
7.4
3.6
4.3
3.2
2.9
2.6
3.8
NOX
1.6

1.4

1.6
1.5
1.5
1.9
1.5
1.9
1.9
1.7
1.9
1.9
2.0
1.9
1.6
1.9
1.4
MPG
20.1

12.6

12.4
15.6
14.4
13.8
16.8
14.9
13.1
13.0
12.8
12.3
11.9
11.9
11.6
11,7
10.4
REFS. 9, 10

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                            15
                         TABLE 4.2
                Exhaust Emission Test Summary
               California Division of Highways
                 Underfloor Converter Fleet
                13 Oldsmobiles (No air pumps)
Average Test
Mileage
194
4108
8222
12296
16022
20535
24976
249502
29635
No. of
Cars
13
13
13
5
13
5
3
12
2
19/:>
HC
0.19
0.20
0.24
0.25
0.24
0.23
0.21
0.23
0.19
EPA Grams
CO
1.90
2.22
2.14
2.83
2.87
2.13
3.16
2.12
2.23
/Mile
NOX
1.75
1.86
1.84
1.75
1.79
1.72
1.93
1.86
2.20
                    12 (AIR) Oldsmofoiles
Average Test
  Mileage

     230
    4426
    8820
   13857
        No. of
         Cars

          12
          12
          12
          12
   1975 EPA Grams/Mile'
  RC

0.30
0.31
0.31
0.35
 CO

0.9i
0.98
1.21
1.50
1,48
1.62
1.72
1.58
NOTES:
        1
Certification test procedure
          Slave canister procedure^  CM reports  that  1  g/mi  CO
          should be added to CO levels due to variations  in
          test procedures
                                                REF.  11

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                     16
                  TABLE 4.2  (Continued)
     "In Service" Fuel Economy Summary
       California Division Of Highways
         Underfloor Converter Fleet
        13 Oldsmobiles (No Air Pumps)


Average Fuel Economy (MPG)             10.6

Fuel Economy Range (MPG)             10.2 - 11.0
            12 (AIR) Oldsmobiles


Average Fuel Economy (MPG)             11.0

Fuel Economy Range (MPG)            10,0 - 11.S
Ho comparable fleets of production vehicles available
for comparison.

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                                    17
       Seventy to eighty percent of the unburned HC and CO of a 1975
catalyst-equipped vehicle is given off during the first two minutes
after cold start.  Methods to reduce the amount of fuel used during
choking will both lower emissions and increase fuel economy.  The
1975 emissions-control systems will use reduced choking times and
will employ provisions for using exhaust heat for early fuel
evaporation.  Systems that have promise of effecting even better
control during start-up include electrical heating of a charge of
fuel, electronically operated chokes, use of a small catalyst during
start-up that will reach operating temperature in a short time, etc.
Further reduction in emissions is possible by increasing the quantity
of active material in the catalyst and in some cases, by increasing
catalyst volume.
       To reduce NO  levels below the 1977 level of 2.0 g/mi while
                   jC
retaining control of HC and CO, increased amounts of EGR will be
necessary.  The resultant richer mixtures required to maintain flame
speeds and driveability will lead to fuel economy penalties.  The
latter may be minimized by using greater spark advances, but this will,
in turn, require extra control of HC.
       Except for small, low-powered cars, where NO  outputs are
basically low due to the low flows required, it is doubtful whether
a significant number of vehicles with conventional engines and
oxidation catalysts would be able to reach levels <£ 0.41/3.4/1,5 g/mi
without additional control measures or without excessive fuel
economy penalties.

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                    5.  AIR/FUEL MIXTURE PREPARATION
5.1  Iii t r o due t i on
     For emissions control to 1975 levels, considerable improvement
in mixture preparation and delivery has been achieved.  To reduce
engine emissions and also to prevent an excessive burden on the
oxidation catalyst, reductions of variations of A/F ratio from
cylinder to cylinder and over the driving cycle have been necessary.
     Further improvement in mixture preparation will be required to
meet stricter standards.  A closer A/F ratio control is essential for
lower NO  emissions because all known NO  control methods result in
        x                               x
poor driveability and fuel economy if the mixture is allowed to vary
widely.  NO  catalyst technology specifically requires very high A/F
           jC
ratio control which cannot be met with good presently used carburetors,
       Another approach to minimize emissions and to maintain or
improve economy does not involve the use of catalysts.  In a warm
engine, the optimum A/F ratio for minimizing all three pollutants is
on the very lean side of stoichiometry; e.g., at A/F ratios larger
than 18-20:1 as illustrated in Figure 5.1 where HC, CO, and NO
                                                              j£
emissions are plotted against A/F ratio.  With current technology
in mixture preparation and engine design, however, very lean mixtures
rob the engine of horsepower output and increase fuel consumption,
shown also in Figure 5.1.   Engine and mixture-preparation technology
are under development which will extend the range of adequate fuel
economy and power output of lean mixtures as shown by the dotted
lines in Figure 5.1.   In this section,  a discussion of improved
mixture preparation methods will be presented which will be required
for advanced emissions-control  systems on conventional engines.
Included will be advanced design carburetors, fuel injection and
feedback control systems.   Later sections of this report will deal
with the emissions and fuel economy potential of lean engines and
NO  catalytic systems.
                                   18

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                              19
                Stoichsometric
                                       Conventional Engine
                                    — Lean Burn Engine
10
                       AIR/FUEL RATIO
FIGURE 5.1  The  Relationship of Typical  Engine Emissions  and
Performance to Air/Fuel Ratio.  The Vertical Scale is Linear
and Shows Relative Rather than Absolute  Values for Each Param-
eter.

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                                 20
5.2  Carburetors
     a.  Conventional carburetion— The amount of fuel issuing from
the jet situated in a Venturi of a carburetor increases at a faster
rate than that corresponding to an increase in air intake.  The
mixture formed by a simple carburetor thus becomes richer as the
engine aspirates more air and, consequently, a mixture which is
correctly proportional for high air (full load) will be too lean at
lower air flows (idle and part load).  Figure 5.2 illustrates the A/F
ratio control of such a simple carburetor as a function of Venturi
vacuum (or the equivalent parameter engine rpm at part load).
         An engine equipped with such a carburetor will run too rich
at medium to full-load operation if excessive leaning out at idle is
to be avoided, and for this reason such an engine would be highly
polluting and poor in fuel consumption.
         Modern carburetors achieve better A/F ratio control over the
full speed/load range by using idling and full-load Venturis, idle
speed and transition orifices to supply additional fuel at idle,
acceleration pump, etc,
         Figure 5.3 illustrates a cross section of a Weber
                    12
multijet carburetor.
         A typical calibration curve which is conventionally used to
provide for the mixture needs of an engine operating under all
spead-load conditions is illustrated in Figure 5.4 for a single-barrel
carburetor as used on the Vega 4-eylinder engine and with a carburetor
                                              13
used on Chevy 6's in the 1960's (dotted line).    The throttle is
gradually opened from A(a) to D(d) and held wide open from D(d) to
E(e) and F(f),  As the engine slows down the D-E-F line the A/F
ratio leans out because less air is being pulled through the
carburetor.   The engine comes to a lugging stall at point F.

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                            21
    0.36,—
                2345



                DEPRESSION IN THROAT (Ib/in2)
FIGURE 5.2

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                         22
                                      Gam
                                         Gm
FIGURE 5.3  Idle Speed Circuit
Gam - Idle Speed Air Jet
Gm  - Idle Speed Fuel Jet
G   - Main Fuel Jet
1   - Idle Speed Mixture Orifice
2   - Transition or Progression Orifice
3   - Idle Mixture Adjusting Screw
U   - Throttle Setting or Idle Speed Adjusting Screw
Source:  Reference 12

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                                 23
 DC

    10



    11




 O  12




 S  13
 -  15
 <
    16-



    17 -
    19
         0.5   1    234    567


                                 ib AiR/min


FIGURE 5.4
                                                9   10  11   12   13
Source;   Reference  13

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                                  24
         Pre-emission-control carburetors were able to reproduce
the A/F calibration curve within a band of +57=  to  10%;  present
carburetors have narrowed the band to+3%.   These figures are,
however, deceptive because they do not reflect the dynamic A/F ratio
changes which occur during acceleration, deceleration modes, changes
in altitude, air and fuel temperatures, air humidity, etc., which all
affect A/F ratio control,
         A more serious problem with conventional carburetors is the
variation in A/F ratio distribution from one cylinder to another
cylinder.  This problem arises from the fact that normal aspiration
in a fixed Venturi carburetor results in relatively large fuel
droplets which tend to segregate in the manifold.  This segregation
is more pronounced with cold engines, and under idle or low-load
operation of the engine where the low air velocity through the
Venturi results in large droplets which are difficult to distribute.
         Variations as large as 207= in the cylinder-to-cylinder A/F
ratio distribution have been reported for some European and American
                         14 15
engines (see Figure 5.5).  *    The resulting emissions are high
in HC and CO and can lead to premature catalyst failures.  Improved
carburetor manifold designs have reduced the A/F ratio spread to
about 5%.
         The cost of the more complex carburetors has been increasing,
A simple single-barrel carburetor costs approximately $5 to $10; the
more complex multibarrel carburetors, with altitude compensation
and other ancillary controls, may cost as much as $40.  The fuel
economy and emissions control which can be realized with these
carburetors are marginal when compared with new mixture  preparation
devices, and it is reasonable to assume that the conventional
carburetor will be gradually phased out by other devices in the
foreseeable future.

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            25
 BSFC
 Brake
 Specific
 Fusl
 Consumption
          15.5      13.3
FIGURE  5.5   Air/Fuel  Ratio
Distribution in an  8-Cylinder
Engine.
Source:   References  14,  15

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                                     26
      b.   Variable Venturi carburetors  andconstant depression
 carburetors — Variable  Venturi  and  constant-depression carburetors
 overcome the problems  of low air velocities which  were  described in
 the previous section by  varying  the  area  of the  Venturi in accordance
 with the weight of air that  is required per unit time by  the engine.
 The Venturi can thus provide depressions  and  air velocities which are
 adequate to cause fuel to flow and be  dispersed  under most operating
 conditions of the engine.  These carburetors  also  feature  a variable
 area fuel orifice that varies with the changes in  area  of  the Venturi
 in such  a manner that  the  desired A/F ratio is provided at all  times.
 Figure 5.6   shows  an  example of such  a carburetor.
          The piston valve  can slide  up and down  in its  guide and
 change the air passage or  Venturi area.  As the  valve changes the
 area of  the Venturi throat,  it also  moves the tapered metering  pin
 in the fuel jet opening,  and thus it provides a  varying fuel jet
 orifice.   The  dash  pot reduces the movement of the  piston  and
 prevents  rapid upward  movement when  the throttle is operated
 rapidly.
          The  low pressure  or partial vacuum at the  throttle  end  of
 the  Venturi  throat  causes  air to  flow through the  piston vent until
 the  pressures  in  the vacuum  chamber  and Venturi  throat  are  equal.
The  lower  side  of the  flex diaphragm has atmospheric pressure
acting on  it,  and the  force  due  to the pressure  differences  lifts  the
piston up or down.
         Thus,  for each air  flow  rate through the Venturi  there  is a
corresponding position of the piston valve, and  a  particular  value of
the vacuum in  the throat of  the Venturi.   The size of the  fuel  jet
orifice and the taper of the metering pin are made so that  the  fuel
flow with any given position of the piston valve is the desired  flow.
         Most carburetor companies are working on some version of
the Variable Venturi (V.V, ) carburetors.   Most have chosen combination

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                       27
FIGURE 5.6
Source:  Reference 16

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                                  28
carburetors with one barrel operating with a fixed Venturi while the
other performs as a V.V. version.  This version of carburetor appears
to have  the best chance of being interfaced with electronic controls
as will  be discussed later.
         Table 5.1 summarizes some results which were achieved with
a 1973 Dodge Monaco with a 1974 360 CID V-8 engine and the
experimental Holley model 2880 Variable Venturi carburetor.

                             TABLE 5.1
                       A/F ratio control    +31
                       HC    =  1.48 g/mi
                       CO    = 10.28 g/mi
                       NO    =1.8  g/mi
                         5C
                       Spark timing - 60° BTC
                       No air pump
                       10%  EGR
                       Fuel Economy - 11 mpg

         A fixed Venturi 4-barrel carburetor of similar design has
higher HC and CO emissions (approx. HC - 2.5 g/mi,  CO - 20 g/mi) and
equivalent fuel economy.  NO  remains unchanged.
                            x
         In spite of these improvements, the Variable Venturi
carburetor will not achieve the A/F ratio control required for the
three-way catalyst and simultaneous control of HC}  CO, and NO .
                                                             j\,
     c,   Sonic carburetors -- The size of droplets  produced by
a carburetor varies approximately inversely with the velocity of
air flowing through the Venturi.   Figure 5,7 shows  the relationship
between air velocity and fuel droplet diameter entering the intake
manifold,  J     The droplets which are achieved at  sonic  velocities
(approximately 1000 ft/sec) and above are so small  that little
segregation occurs within the carburetor and intake manifold,  and,

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                              29
    800,
    700
tr  600
D
>  500
I
O
    400
UJ
>

oc
   300
    200
    100
0     10
FIGURE  5.7
                   20      30     40     §0     60

                       FUEL DROPLET SIZE (microns)
70
Source:   References  18, 19

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                                    30
consequently, sonic carburetors have much lower cylinder-to-cylinder
A/F ratio variations than conventional carburetors.
         The Dresser carburetor is the best known sonic carburetor
and considerable work is being performed throughout the industry
to develop its potential.
         The Dresser carburetor or "Dresserator" is a  Variable Venturi
                                 tUE
                                 21
                                                              20
carburetor with a mechanically actuated fuel distribution bar.    The
principle is shown in Figure 5.8.
         The device shows promise of improving atomization, mixture
quality, A/F distribution, and control.  It achieves these
improvements by:
     Designing the entrance/exit geometry to produce sonic flow at
     the carburetor throat which results in superior fuel atomization.
     Introducing fuel over a large surface area which is subjected to
     sonic  air-flow  levels.
,     Passing the A/F mixture through a shock wave to atomize the fuel
     and improve mixing.
,     Eliminating flow distortion caused by downstream throttle plates.
     Coupling the throttle with a linear  fuel-control valve to achieve
     constant A/F control.
     Eliminating the choke, although some enrichment is necessary
     during start-up.
         The mixture quality which can be achieved with sonic
carburetors is comparad with conventional production carburetors3 EFI,
s tratified-charge engines (PROCO) and liquid propane (LPG) or liquid
natural  (LNG) cars in Figures 5,9 and 5,10 for various points in the
.   ,              22
induction system.

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                          31
           Fuel Flow




            Sonic Flow  •:•:•_
      Subsonic Fiow
                                   Air Inlet

Fuel Distribution Bar






Supersonic Flow




  Shock Wave
FIGURE 5,8   Sonic  Carburetor Principle,
Source:  Reference 21

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Good
 Poor
                               32
                         LPG or LNG
                                    EFI
        Carburetor   Riser
! ntake
Valve
Spark
Plug
FIGURE  5.9   Ford Motor Company Estimate of  Induction System
Mixture Quality Trends Under  Hot Operating  Conditions.
Source:  Reference 22

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                      33
Good i—
                     LPG or LNG
 Poor
 FIGURE  5.10   Ford  Motor Company Estimate
 of Induction  System Mixture Quality Trends
 Under Cold Start and Drive Conditions.
 Source:  Reference 22

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                                     34
         With exception  of LHG and LPG, sonic carburetion  provides  the
most homogeneous mixtures and thus improved distribution.
         Sonic carburetion is still in the development  stage  and  a
variety of problems remain to be resolved among them:
     Actuation forces under sonic conditions are high and  lead  to
     rapid component wear,
     Need for altitude and temperature compensation,
     Manufacturability and durability,
     Cold start where sonic velocities cannot be achieved,
     d.  Hp_t:-spot carburetors --As was shown in Figures 5,9  and 5,10,
LNG and LPG produce better mixtures than gasoline because  they  evaporate
more readily than gasoline in the operating temperature range of  the
engine.  Similarly, cylinder-to-cylinder A/F ratio variation  could  be
eliminated by vaporizing and mixing the gaseous gasoline with the
incoming air.  Several difficulties are associated with this
approach are:
     The heat required to vaporize all fuel under full-load conditions
     is over 2KW and cannot be supplied by the automotive  electric
     power.
     The fuel evaporator has to be designed to prevent  simultaneous
     heating of the incoming air and associated volumetric efficiency
     losses,
,     Vapor lock has to be prevented,
Hone of the  fuel evaporation systems which are presently under
evalutation  has resolved these problems satisfactorily.
         Most automobile manufacturers use hot spots or early fuel
evaporation  (EFE)  devices to help during cold start.  These are
turned off as soon as the engine reaches operating temperature  and

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                                    35
therefore do not influence the cylinder-to-cylinder A/F ratio
distribution of the warm engine.
         The Ethyl Corporation, Shell Laboratories in England, and
British Leyland  '  *   are experimenting with evaporative heaters
which are kept in operation during the full operating range of the
engine.  The objective of these approaches is to improve the A/F
ratio distribution to allow ultralean operation of the engine under
all load conditions.
         The Ethyl Corporation's hot-box manifold is shown in
Figure 5.11.
         The hot box is situated underneath the primary barrels of
a Quadrajet carburetor and sunk into the exhaust manifold crossover.
The fuel/air mixture of the primary barrel passes through the hot
box under all driving conditions; the air/fuel mixture of the
secondary barrel, on the other hand, bypasses the hot box under
all conditions.
         Since the air-flow velocities of the secondary barrel
provide for good fuel distribution without evaporation, the resulting
A/F distribution is better under all driving loads.  The main flow
of air is not heated by this system and, therefore, the volumetric
efficiency is maintained.  The cylinder-to-cylinder variation of
this carburetor mounted on a 350 CID Plymouth engine is shown in
          23
Table 5,2.
         The A/F ratio spread with this carburetor is approximately
3% under idle and 1.6%, at 30 mph.  This is an improvement of a factor
of 1. over a conventional carburetor.  Further improvement are
anticipated from a variable Venturi arrangement in the secondary
barrel.

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                       36
                    a-j       n
                         "
                                        Recycle
FIGURE 5,11  Ethyl  Corporation's Rectangular Hot

Box Manifold for a  360  CID  Plymouth.
Source:   Reference 23

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                      3?

                   TABLE 5.2




  Cylinder-To-Cylinder Distribution  Spreads
Speed
Idle
15
30
50
Cruise
A/F1 F/A2
16,3
17.5
17.3
16.6
.061
.05?
.058
.060
A Distribution
A A/F A F/A
0.50
0,49
0.28
0.47
.0020
.0016
.0009
.0016
 A/F = air/fuel ratio

2
 F/A = fuel/air ratio

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                                    38
          Typical emissions results for a modified* 1974 Dodge 4,500 Ib
360 CID engine are (g/mi) :
                HG  --  1.33,  can be improved to 1,1-1,2
                CO  --  7.80,  can be improved to 6-7
                NO  --  2.76,  can be improved to 2.3-2.5
                  Jv
          Fuel economy -- 10.7,  can be improved to 11.2 mpg

          Base-line figures for  the conventional Quadrajet carburetor
          are (g/mi):
                HC  --  2.8
                CO  --  26.0
                RO  --  2.5-2.7
                  x
          Fuel economy -- 11,0

          The Shell Laboratories' (England)  Vapipe approach is to use
the exhaust heat to heat and evaporate all the fuel under all engine
                     24
operating conditions.     Heat  is transferred to the carburetor with
heat pipes which are connected to the exhaust manifold (see Figure 5.12).
          The results  are similar to those achieved by Ethyl Corporation:
      The engine can be operated at very lean A/F ratios without losing
      driveability.
      The A/F cylinder-to-cylinder distribution is excellent (Table 5,3).
•'•'Equipment:      Carter Thermo-Quad Carburetor
                Electric choke assist
                Ethyl hot-box manifold
                EGR -- control with Venturi and throttle position sensor
                Timing 5° ETC

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                              39
FIGURE 5,12  Location of Vapipe,
Source:   Reference 24

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                     TABLE 5.3
    COMPARISON._OF AIR-FUEL RATIO DISTRIBUTION
WITH AND WITHOUT VAPIPE - l.B LITRE (110 CU.IN.)  CAR
Test
Condi tion
Idle
Road Load
30 raph
48 km/h
Road Load
50 mph
80 km/h
Road Load
70 mph
112 km/h
Full Throttle
30 mph
48 km/h
Full Throttle
50 mph
80 km/h
Standard Car - Standard Setting
Overall
Tailpipe
13.2

14.2

15.4

15.0

14,3

13.6
Cyl.l
13.1

15.4

15.8

15.3

14.7

13.3
Cyl.
2 & 3
13,4

13,5

15.2

14,9

13.5

12,9
Cyl, 4
12,9

14.2

15.6

16.1

15.3

14.8
Vapipe Car - Standard Setting
Overall
Tailpipe
13.1

13.4

15.8

14.8

13.6

13.5
Cyl.l
13,1

13,5

15.8

14,8

13.7

13.8
Cyl.
2 & 3
13.1

13,4

15,8

14.7

13.6

13.5
Cyl, 4
13.1

13.4

15.8

14.7

13.9

13.6
Vapipe Car - Lean Setting
Overall
Tailpipe
16.5

16.3

17.9

16.6

17,1

16.6
Cyl.l
16.4

16.6

17.7

16,7

17.4

17.0
Cyl.
2 & 3
16.5

16.3

18.0

16.6

17.2

16.6
Cyl. 4
16.4

16.5

17.9

16.6

17.5

16.7

-------
                                    41
     The emissions of all  three pollutants are lowered.
     Fuel economy is improved over that of the same engine with a
     conventional carburetor,
     e.  Carburetor with ultrasonic fuel dispersion — Recently
several carburetor-like devices have been proposed which use
ultrasonic energy to achieve good fuel dispersion and cylinder-to-
cylinder mixture distribution.  One version is being developed by
Autotronics.  Another version, which has been proposed by Dr. A. K.
                                                           f\f
Thatcher and Dr. Ed McCarter, Florida Technical University,   uses
a magnetostrictive transducer at frequencies of 20,000 Co 40,000
Hz to break up  the fuel stream into very small droplets.  The device
is shown in Figure 5.13.   Fuel injectors spray fuel onto the surface
of the horn of  a magnetostrictive transducer where the fuel is
atomized into very small droplets which are mixed with the flowing
air.  The device was evaluated on a Plymouth Duster with a 225 CID
slant six engine and is summarized in Table 5,4.

                                      5.4
                Duster with                        Duster with
                Ultrasonic Device                  Std. Carburetor
                     (g/mi)                       (base-line) (g/mi)
                 HC  - 0.44                           4.9
                 CO  - 0.88                           6.6
                 NO  - 1.0 + 301                      3.0 to 8.0
                 MPG - 22                             18

         The base-line HC  and NO  emissions seem overstated; however,
the improvements in emissions levels with this system are believable,
The large difference in fuel economy cannot be justified by what is

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MAGNET
            DRIVING COILS
FIGURE 5.13 Ultrasonic Carburetor,
                                                                               FUEL
                                                                               INJECTOR
Reprinted courtesy  of Popular Science, 1973, Popular Science Publishing  Company
Source;  Reference  26

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                                     43
known about  the device  alone.  The  drawbacks  of  the  system,  as
presently  implemented,  are high  power  consumption, noise,  complexity,
and  thus,  high cost.  Therefore,  it seems  that the objective of
better fuel  dispersion  may be  accomplish more easily with  a  sonic
or hot-spot  carburetor  or fuel injection.

5.3  Fuel  Injection  Systems
     a.  Electronic  fuel injection  - speed and density  systems — The
oldest electronic  fuel  injection system (invented by the Bendix
Corporation  approximately 15 years  ago and perfected and manufactured
by Robert  Bosch, Germany) measures  air density and engine  speed  to
derive the air quantity drawn  in by the engine and to inject the
appropriate  amount of fuel.
         Robert Bosch started  production of this system In 1967  and
has  presently 1.5 million of the  D-jetronic EFI  types in the field
installed  on 40 different 4-,  6-, and  8-cylinder engines.  The
                                                      27 28
principle  of the system is illustrated in  Figure 5.14.  '
         The air quantity drawn  in  by  the  engine is  determined by
measuring  the engine rpm and electronically multiplying this figure
by the engine displacement constant.   A manifold vacuum pressure
transducer and an ambient air  temperature  sensor convert the air
volume to  standard temperature and  pressure (STP).   The electronic
control logic processes these  signals  and  injects the appropriate
amount of  fuel into  the intake manifold through fuel injectors which
are positioned on top of the cylinder  heads.  Fuel is fed  to these
injectors  through a well-regulated, pressurized fuel rail.
         The D-jetronic system is a pulsed  injection system  where the
quantity of  fuel is modulated  by  changing  the length of the  injection
pulse.   The  D-jetronic  system  sells to the  original  equipment market
                                                                 29
(OEM) in Europe for approximately $120 for  a 4-cylinder version.
For this reason, it has found  only  limited  application  in  spite

-------
                                 44
                                       Injector
                       rpm
                                                  Manifold
                                                  Density
                                                       Air Flow
Air Flow {!b/min} =
Displacement (I3/rew) X
Speed (rev/min) X
Cylinder or
Manifold Density




ECU


























Fuel ^ 	















\

\

I




mm.

)?
\"





j
{

\
I

Z
1
I






—




^



f








_




\

i
]

i




H

M
w/
-f
\


FIGURE  5.14
Source:   References  27, 28

-------
                                    45
of the fact that it has been offered in Europe for over seven years.
The Bendix Corporation in the United States has developed a similar
speed density system but has failed to find wide acceptance again,
                                          27
mainly due to the high cost of the system.
         There is considerable controversy about the benefits of
electronic speed density fuel injection systems:
     It is well established that the maximum power output for a given
     engine can be improved; for example, with electronic fuel
     injection (EFI), a 208 liter Daimler Benz gasoline engine
     delivers 185 hp at wideopen throttle (WOT) and only 150 hp with
                  30
     a carburetor.    This advantage is due to the better volumetric
     efficiency and full power enrichment with EF1,  (The EFI
     manifold has fewer obstructions for the inrushing air.)  This
     advantage is mainly realized at full throttle, particularly
     with high speed European engines - most current U.S.  cars
     rarely operate at full load and would not benefit from EFI.
     Electronic fuel injection can offer better cylinder-to-cylinder
     A/F ratio distribution for poorly designed engine manifolds
     and engine types which have difficult induction problems.  An
     example is the air cooled opposed piston engine used by
                14
     Volkswagen.    This engine has long intake manifolds and a
     cylinder firing sequence which makes it difficult for some
     cylinders to get the correct charge.  Traditionally,  this engine
     was carbureted rich in order to assure that all cylinders had
     adequate mixtures.  The consequences were high emissions.
     Electronic fuel injection solved the problem by supplying
     each cylinder with the appropriate amount of fuel.  Electronic
     fuel injection, in itself, does not have any advantage over a
     well carbureted engine.  For example;

-------
                                    46
                                                        31
                Saab 2 Liter Engine 3,000 Ib, Automobile
                     (Raw Engine Emissions)
                                          HC     CO     NOX     MPG
                D-jetrcmic
                  (dual catalyst)       1.18    40,9    2.19    16
                Carburetor
                  (dual catalyst)       1.9     40,7    2.4     17.7
                Close loop K-jetronic
                  (3-way catalyst)      0.9      8.14   2.2     19,3
     Electronic fuel injection improves cold-start performance, again,
     particularly for European engines with simple carburetors and
     choke systems.   U.S. cars do not benefit from this feature.
     Some European manufacturers "have opted to use EF1 rather than
     to design an advanced carburetor because it was cheaper to do so,
         In summary, D-jetronic EFI can offer some advantages in A/F
ratio distribution for a few engines with difficult manifold and
firing sequence problems.  It improves cold start and power output
at WOT,  It does not offer fuel economy and emission advantages over
well carbureted engines,
     b.  Electronic fuel injection - air mass system (L-Jetronic)—
In 1972 Robert Bosch produced the L-jetronic system, a second
generation EFI3 which monitors the quantity of air drawn in by the
engine directly with an air mass sensor as shown in Figure 5.15.  This
                                                  32-34
system has been described in several publications.       The air
mass is measured by a flap situated in the main air stream.  The
force of the flowing air on the flap is balanced against the force
of a return spring.   To eliminate rapid pulsation, the device
incorporates an air chamber and another flap which acts as a dash
pot damper (stabilizer volume).  A butterfly valve in the air flow
measuring flap absorbs backfiring pulses.  The flap angle is converted
into voltage by the potentiometer which is attached to the axis of
the flaps.  This device eliminates the pressure and temperature

-------
                              47
FIGURE 5.15
Source:   References 32, 33, 34

-------
                                     48
 sensors  of  the  D-jetronic  system  and  simplifies  the  electronic
 circuit.
          The  rest  of  the L-jetronic system  is  similar  to  the  D-jetronic
 system.   It has  a  pressure regulated  fuel rail,  port injection,  an
 additional  injector for cold  start, etc.  The  L-jetronic  system,
 however,  offers  the following improvements:
      Improved start-up which  leans out  the  engine  faster.
      Deceleration  control.
      Simultaneous  injection of all injectors  (rather than sequential)
      which  allows  the injection pulse length  to  increase  and  to  reduce
      the  injection time error.  For example,  at  fall load,  the
      injection pulse  is 8  msec with the L-jetronic and 4  msec with the
      D-jetronic  EFT.  Since the pulse rise  time  is 1.6 msec,  the
      errors introduced at  a 4-msec pulse width are considerable.
          The  L-jetronic EFI is more rugged  and measures air more
 accurately.   For example,  the air-mass meter  is  independent of
 barometric  and back pressure changes which  throw off the  calibration
 of the D-jetronic  system,  and it monitors air  flow independent of
 EGR.
          The  L-jetronic system is approximately  10%  cheaper than
 the D-jetronic system, viz. s approximately  $110  for  a  4-cylinder
 European  engine versus approximately $120 for  the equivalent
 D-jetronic  system.   Because of these advantages, most  users of
 D-jetronic EFI,  particularly Volkswagen, will  switch in 1975  to
L-jetronic EFI.
         The  raw emissions of the L-jetronic system  are lower than
 those achieved with D-jetronic EFI; 1975 Federal standards  can be
met comfortably.  For example, a 1.6 liter  air-cooled  Volkswagen
              ,  35
engine measured:

-------
                                    49
                     HC   - 1.16 g/mi
                     GO   - 7.1  g/mi
                     NO   - 1.22 g/mi
                       5k

         The L-jetronie system does not seem  to offer significant
                                              35
fuel economy advantages.  Volkswagen reports,   for example 18,3 miles
per gallon in 1974 vs. 17.8 miles per gallon  in 1975 for their Type 2
air cooled engine.  Other models show slight  increases in 1975,
         In summary, the L-jetronic system reduces emissions when
compared to the D-jetronic system.  These improvements are due to
better air measuring inputs, improvements in  the start~ups
deceleration controls, and injection timing.  The L-jetronic system
is capable of meeting the 1975 federal standard but cannot meet 1975
California standards without oxidation catalysts or thermal reactors.
Fuel economy remains equivalent to D-jetronic or well carbureted
engines.
     c.  Mechanical fuel injection.(K-jetronic system) -- The
                  ^> £" Q "J
K-jetronic system  *   uses the intake air volume as the controlling
variable to determine the A/F ratio and to eliminate the need for
electromechanical conversion.  Figure 5.16 shows the schematic of
the system.
         The floating flap air-sensor plate is mounted on a lever
having a balanced weight attached to the short end.  The flow rate
of intake airlifts  the plate until an equilibrium is reached
between air flow  and hydraulic counter pressure which acts on the
lever through a controlled piston.  In this balanced position, the
plunger maintains a certain position in the fuel distributor, thus
opening small metering slits, one for each engine cylinder.  The fuel
supplied by a pressurized fuel rail system passes through the slit
openings to the injection valves.  The correct amount of fuel is
provided by the slit openings, than in the injection valve as in

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                                50
Injection
Valve
Starting
Valve   ~j
   Injection
!   Line
i	 Fuel-Air Regulator
   and Flow Divider
                     7
               Fuel Pump
FIGURE  5.16
Source:   References 36,  37

-------
                                  51
electronic fuel injection.
         Hydraulic counter pressure acts on the top of the control
piston to influence the fuel quantity needed by the various operating
conditions of the engine.  By exerting more force on the top, the
plunger travels less, and less fuel flows to the injection valve.
The opposite is true when the pressure is released.  The control
pressure is varied by control-pressure regulators, one regulating
according to engine and outside temperature and the other according
to accelerator pedal position.  The controlled pressure regulator for
temperature compensation maintains the correct A/F ratio by enriching
the mixture during engine warm-up.  As the engine reaches its normal
running temperature, it leans out the mixture.  This control-pressure
regulator contains a bimetal spring which acts on a spring-loaded
diaphragm (see Figure 5.17).  For example when the engine is cold,
the diaphragm keeps the inlet open to maintain a minimum pressure
on the plunger of approximately 2,3 atm.  As the heating coil of
the bimetal spring heats up, it permits the diaphragm to close off
the inlet opening, thus increasing the control pressure and leaning
out the mixture.
         The control-pressure regulator for throttle vavle position
compensation is mounted on the throttle valve shift (see Figure 5,17),
According to accelerator movement, the control pressure on top of
the plunger is again changed to provide the correct A/F ratio.  When
the throttle is at idle, the control pressure is maintained at 3 atm,
at mid-range throttle opening, 3.7; and at wide open throttle, 2.9;
thus increasing fuel delivery as the throttle is depressed.
         The K-jetronic system has a starting valve which provides
additional fuel during start-up conditions, and has a number of
significant advantages over both electronic fuel injection systems:

-------
                                                   52
                                                                                           t
                                                                                     2.7-3.1
                                                                                     bar
                                                                                              To
                                                                                              Tank

                                                                                          t    f

u.







2 — 1
To     t

Tank  3.7 bar (WarmJ
                                     8. Control pressure regulator lor throttle valve position compensation.
                                     A—idle position; B - rnidrsnge petition; C—full-throttle position.
                                             t            I
'•;                   o       o
"'.  Contfol pressure regulator for
wjrn^.running compensation.
A -cold position; S—warm position
FIGURE  5.1?
                                      9  Fuel accumulator prevents vapor  10- Auxiliary air device assures good
                                      locking of the system.              8iMuel fatio duri"8 deceleration.
Source;    References  36,  37

-------
                             53
It is a simpler system and is understood by mechanics.
It is lower in cost.  The OEM cost for the system in small
quantities is approximately $100 and is likely to be lowered as
the volume production commences,
The K-jetronic system is slightly better than the L-jetronic
system in controlling emissions and improving fuel economy
because it minimizes time lags associated with sensor signals
and fuel-injection pulses.
The K-jetronic system is capable of meeting the 1975 federal
standards, but it cannot meet the 1975 California standards
without a catalyst.
In summary:  The K-jetronic system provides the same advantages
over carburetors as the other two electronic fuel-injection
systems; namely, higher power output under wide open throttle
conditions, less air induction problems and better cold start.
The fuel economy is approximately the same as with the L-jetronic
system, although Audi, Volvo, and Saab claim some minor
advantages,  Volvo claimed that the fuel economy of their two-
liter, carbureted engine increased from 17 mpg to 19 mpg for
                                                        Q O
the same engine with a K-jetronic fuel-injection system.
     39
Saab,   on the other hand, showed an example during the
Washington presentations of a carbureted engine with better fuel
economy than one with K-jetronic injection.
This difference in opinion illustrates the danger of
extrapolating the emission and fuel economy results achieved
with one type of intake-manifold-engine combination as compared
to another even if the same carburetor or fuel-injection system
is used in both.

-------
                                    54
     The emissions from K-jetronic injection are equivalent to those
     of the L-jetronic system.

5,4  Feedback Systems
     The A/F ratio of an operating engine Is influenced by the
temperature of the air, temperature of the fuel, the humidity of
the air, the chemistry of the fuel which affects density surface
tension and viscosity, the absolute pressure of the air, the back
pressure of the engine and the  shifts in calibration of fuel
metering rods, orifices, etc.  Of all these variables, only a few are
monitored with present fuel-metering devices:
     The advanced carburetor will have altitude compensation but has
     no sensors for air temperature, humidity, etc.
,    The electronic and mechanical fuel-injection systems will also
     incorporate altitude compensation and air temperature measurements
     but do not monitor variables such as humidity, fuel viscosity,
     etc,
For these reasons, open-loop fuel metering cannot be correct under
all conditions of vehicle operation.  Only a closed-loop system which
monitors either the composition of the exhaust gases or some engine
output parameter, such as horsepower output, can maintain the A/F
ratio within correct limits by  constantly supplying corrective
signals to the primary F/A metering device,
     Two main approaches are being pursued at the present time:
     Systems based on the exhaust-gas composition, specifically,
     systems monitoring the oxygen content of the exhaust system;
     Systems based on engine output parameters, particularly horsepower
     output.

-------
                                    55
     a> Feedback systems based on the 02  - exhaust gas sensor and
EFI, mechanical (continuous) fuel injection or electronic
carburetors — In 1971, Robert Bosch proposed a new exhaust-gas
composition sensor which provides a strong variable voltage signal
                                                         40
around the stoichiometric composition of the A/F mixture.    The
sensor output was used to close the feedback loop with the L-jetronic
electronic control unit and to correct the fuel injection pulses and
maintain the A/F ratio at exact stoichiometric composition.  The
control achieved with  this feedback was typically an order of
magnitude better than  that achieved with advance carburetors or
approximately +0.370 vs the +3% achieved with the best carburetor
system.
         The heart of  this control system is the oxygen sensor.  Such
a sensor is shown in Figure 5.18.  It consists of a doped ZrO  tube
with phatinura electrode on each side.  One side of the sensor  is
exposed to the exhaust manifold gases, the other to the atmosphere.
The sensor operates as an electrochemical oxygen concentration cell
with ZrO  solid electrolyte.  The platinum electrode acts as a
reaction site for the  reaction:

                        CO   +   0   C07 and
                        HC   +   0   H20 + C02 ,

and the sensor output  is determined by the oxygen partial pressure
of  these reactions or  the concentration of oxygen on the surface
of  the senor rather that the "free" oxygen concentration in the
exhaust stream.
         As the mixture goes from rich to lean, the partial pressure
                                                       12
of  oxygen on the  surface will change by a factor of 10   or more  and,
according to the Kernst equation, a step-like voltage  change of
almost one volt will appear across the electrodes of the  sensor as

-------
                                56
                                                       {exhaust}
                                   Zircondioxide
                      Platinum Surface
FIGURE 5.18
Source:  Reference  40

-------
                                  57
shown in Figure 5.19.  A signal will always occur  at stoichiometrie
exhaust gas compositions regardless of temperature or exhaust gas
flow rate.  The rise time of the signal is very rapid (milliseconds).
The sensor has to be brought to at least 400 C before a useful
signal appears and the output is temperature dependent as in Figure
5,20.    By choosing the control point at 500 mV or below, the
temperature sensitivity can be eliminated because temperature
changes occur mainly at the rich end of the output.
         The problems which plagued the oxygen sensor a year ago
thermal cracking, aging, and seal leaks, have been virtually
eliminated, and Bosch in Germany and UOP in the U.S. claim to have
sensors which can be guaranteed for 12,000 miles or more.  The
evidence submitted to support these claims was convincing.
         The oxygen sensor feedback loop can be used in conjunction
with the L-jetronic EFIS the K-jetronic mechanical injection system
or electronic carburetors.  The cost of feedback-control systems may
decrease rapidly because they may eliminate many presently used
ancillary control such as fast chokes, altitude compensation} air
pumps, EGR, etc.  The feedback control is very exciting new technology
with great potential to achieve Low emissions with low fuel
consumption and control system cost.
     b.  Feedback system based on engine output sensors -- Dr. P.
          42
Schweitzer   has proposed to use an engine feedback signal to vary
the mixture ratio of the engine under all driving conditions.  The
principle of the control or "Optimizer" system is illustrated in
Figure 5.21.
         In this version of the control system, the intake manifold
system is provided with an auxiliary air intake passage.  A dither
plate continuously oscillates to change the air intake within narrow
limits.  As the mixture composition changes, the engine speed
fluctuates within narrow, but well-defined limits.  These variations

-------
                   58
   f.OOOi-
£   800

E
 tfl

s

LU
     600
I-


O
g   400
     200
       0,8     0.9     1.0      1.1      1.2


                       X


 FIGURE  5.19  Sensor Characteristic,
 Source:   Reference 40

-------
 E  800
 I-
 D
 O
 ir  600
 O
    400
    200
                                                                     400 C
                      400

                  TEMPERATURE ("O
700
                           AtR/FUEL RATIO
1'IGURE  5.20
Source:   Reference  4L

-------
                          60
                 To Engine
FIGURE 5.21  Optimizer Control.
Source;  Reference 42

-------
                                    61
in engine speed are monitored by a deceleration/acceleration sensor
(the Ceisigj the derivative of rpm information) and fed into the
control logic. The conOrol logic adjusts the main air intake to the
engine in such a way that the change maximizes engine rpm.  In this
fashion} this control optimizes horsepower output of the engine under
any driving condition and thus minimizes fuel consumption,
         Dr, Schweitzer has made preliminary calculations of the
system and claims lower emissions with improved fuel economy, but the
system has not been tested on a car.
     The optimizer control is probably useful for minimizing fuel
consumption irrespective of engine emissions.  Used in conjunction
with a normally tuned carburetor, operating around stoichiometry,
the emissions would probably be high because the optimizer control
would tend to operate at the maximum power point which occurs at the
rich side of stoichiometric.
         The optimizer control may have more merit in conjunction
with advanced carburetor or fuel-injection systems which maximize
the power output on the lean side of stoichiometric.  In this
case, good fuel economy may be coupled with low hydrocarbon and carbon
monoxide emissions*  An example would be a combination of optimizer
control with a sonic or hot-spot carburetor.  It seems,  however,
mutually exclusive to optimize fuel economy and minimize NO  with this
                                                           x
method.  Therefore, the usefulness of this feedback control will  be
small to achieve KO^  emissions below 2 g/rai.

-------
                             6.   LEAN  BURN  SYSTEMS
        Maximum rates  of  NO   formation  occur  at  F/A  equivalence
                          A
 ratios about 0.9 (fuel lean),  Figure 5.1.  Significant  reduction in
 NO  can be obtained by operating much  leaner than this.   Further,  at
   x
 lean mixtures,  excess        available provides for complete
 combustion of CO and  HC  and potentially low  levels  of these pollutants
 in the exhaust gas stream.   Advantages in  fuel  economy  can be
 realized by running lean, as long  as means are  taken to ensure
 complete combustion of the  charge.  At very  lean A/F, as  shown in
Figure 5.1,  HC  levels start to increase as the  quench zones become
 thicker and misfire is approached.  Further,  systems that use  lean
 mixtures are generally limited by  an exhaust temperature  which can
 lead to high HC  emissions.   Retarding  timing and reducing the
 compression ratio to  achieve higher exhaust  temperature and lower
 HC emissions leads to fuel  economy penalties.
        Conventional carburetors and induction systems are not
 adequate to maintain  reliable  operation at mixture  ratios of 17:1  and
 leaner.   It is  especially important for lean operation  to have a
 homogeneous mixture delivered  to each  cylinder  at the same A/F ratio,
techniques  to achieve such  mixtures have been described in Section 5;
 namely,  the Ethyl system, Shell Vapipe and Dresser  carburetor.
        Results  from the  Ethyl  system,  featuring a hot-box manifold,
 were presented  on pages  33,36  and  37.   When  this system was modified
 to  include  an exhaust lean  thermal reactor,  with overall  system A/F
 ratio 17:1,  emission  levels  in Table 6.1 were achieved.

                                         43
                                Table  6.1
             1974 Dodge,  360  CID, 4500  Ib  (Ethyl tests)
                                              With reactor
                      HC                          0.55
                      CO                          5.0
                      NOX                        1.40

                                   62

-------
                                  63
Fuel economy,  as measured  on a  cold-start 1972  test  procedure,  was
107o to 15% better  than  that  of  the  base  vehicle.
       The Shell Vapipe  system  is designed for  very  lean operation.
with h-oniogeneity achieved  by fuel vaporization.   Data have  been
obtained on  a  1.8  liter  Morris  Marina  of 2,500  Ib inertia weight with
manual transmission.  This vehicle  is  made for  the European market
so has no EGR,  and very  little  in the  way of  emissions controls except
for the Vapipe,  Results of  the average  of 6  tests on the 1975  FTP
   44
are
HC
CO
NO
X
MPG
A/F
4.
5.
1.
22.
16.
9 g/mi
9 g/mi
5 g/mi
6 MPG
5 to 1
Improvement in fuel economy has been achieved out  to A/F ratio of
20:1 although at  these very lean ratios3  two spark plugs are
necessary, with as much as 80  advance.  A problem that must be
overcome with this system is the time required to bring the heat pipe
into operation (2 minutes).
       The most promising system for obtaining the advantages of
lean operation through improved carburet ion appears at present to
be the Dresserator.  The Dresserator carburetor is a variable-throat,
supersonic nozzle, operating choked for manifold vacuum of less than
3 inches of mercury.  Cold start is possible at A/F ratios of 17,5:1
without the use of a choke,  A/F ratios of 20:1 can be used without
operational difficulties.  Results with the Dresserator on the 1975
FTP are shown in Table 6,2,
       Dresser claims 6073 reductions in HC with the use of an enlarged
exhaust manifold, presumably resulting in increased exhaust reactions.

-------
                                64
                              TABLE 6.2

 A.   1971  Ford Galaxie, 4,500  Lb.3 9:1 CR, 35L CID    (Tests at Dresser)
 Baseline
EC
CO
NO
2-3  g/mi
40   g/mi
4-5  g/mi
             MEG   10.5
With Dresserator & Enlarged
Exhaust Manifold
    HC
    CO
    ND_
      A
    MPG
   0.3
   4-5
1.2 - 1.7
  11
g/mi
S/mi
g/mi
With Dresserator
  at A/F 18:1
No Vacuum Advance
        HC      0.8-1   g/mi
        CO       6-8   g/mi
        NO      1-1.5   g/mi
          X
        MPG    11
B.  1973 Chevrolet Monte Carlo, 4,500 Ib.,  350 CID, no EGR
            (Tests at GM)      (Conventional Exhaust)
                   HC     0.849   g/mi
                   CO     3.95    g/mi
                   N0x    1.915   g/mi
                   MPG   11.51
                                                          46
C.  Results from EPA (75 FTP)
            2600cc,
                             47
     Ford Capri,   retarded timing
     Chevrolet Monte Carlo,  retarded timing
      as above
                                  HC    CO   NOX   MPG
                                 0.68  5.8  1.21  18.2

                                 1.11  5.1  1.56  12.8
                                                    REFS.  45,  46, 47

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                                 65
       Ford currently has an extensive program underway to develop
the Dresser type carburetor.  Results at Ford with a 4,500 lb
                                                                48
inertia-weight Galaxie, 351 CID, no EGR, indicate the following:

                  HC             0.70 g/mi
                  CO             4.17 g/mi
                  NO             1.93 g/mi
                    X
                  MPG           10.7
                       (Results on 75 FTP)

In general terms, these results are consistent with those of GM,
EPA and Dresser.
       The versions of the Dresser carburetor used to obtain the
data quoted above are mostly research tools, and not suitable for
production.  Many significant problem areas remain, including
difficulties in precisely controlling the throat area with the
large forces involved, wear of linkages and cams, correct location of
fuel intake, and operation during unchoked conditions (wide-open
throttle).  Ford is working on three versions of the sonic carburetor.
one with annular throat and two with rectangular throat.  Several
years of development effort are needed before this carburetor can be
considered ready for large-scale production.
       Nevertheless, the Dresserator system, without catalyst or EGR,
can meet California 1975 standards, and, possibly with the addition
of an exhaust thermal reactor and improved inlet manifold, meet
levels of 0.41/3.4/2.0,  Fuel economy at these emission levels should
be equivalent to that of a 1975, 49-state model car.

-------
                       7.  DUAL CATALYST SYSTEMS
      To reach Levels of NO  below 1.5 g/mi while retaining the basic
                           x
components of the 1975 catalytic system will require the use of a
reduction catalyst.  The typical system will consist of a NO  catalyst
                                                            X
located near the engine exhaust manifold, an oxidation catalyst down-
stream, with air injection prior to the oxidation catalyst.  Carburetion
must be rich to provide a reducing atmosphere for the NO  catalyst.
                                                        X
In such systems, during the start-up phase, air is injected upstream
of the HO  catalyst, with the reduction bed acting as an. oxidation
         Jv
catalyst during the start-up period.
      F/A ratio must be carefully controlled for satisfactory operation
of the NO  catalyst.  Too great an input of CO to the bed will lead to
         X
excessive formation of ammonia; too small a concentration of CO will not
provide the correct reducing atmosphere required.  Further, it is
desirable to avoid lean transients when the catalyst is up to
temperature, which may lead to excessive temperatures on the reduction
bed and, at least for some catalysts, cause failure.
      Several techniques have been used to control the ratio of CO to
0  in the inlet gas stream to the reduction catalyst.  Certainly,
one way is the use of improved carburetors which much enable control
of F/A to within 67a over the operating regimes of the vehicle.  This
has generally been the approach of the auto manufacturers, with results
using noble-metal catalysts as shown in Table 7.1 below.
      An accumulation of data on performance of NO  converters developed
                                                  X
by various catalyst manufacturers and tested on General Motors vehicles
                      49
is shown in Figure 7,1    Even the most attractive catalyst from this
chart, curve L, was over the CO standard after 8,000 miles (Figure
7,2).     More recent low-mileage data from GM on dual catalyst systems
are shown in Table 7.2a,b.   Fuel economy for the base 1975 vehicle
is 12 mpg.    it can be seen that} for small cars, results on the best
 experimental vehicles indicate levels under 0,41/3.4/1.0 up to 10,000
to 20,000 miles with fuel economy between 0% and 5% worse than 1975

                                   66

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67
TABLE 7.1
Experimental Results - Dual Catalyst System
Manufacturer
1.


2.



3.


4.


5.






6.


7.

8.


9.




10.



11.

Ford Galaxie, 351 CID

49
Ford Galaxie, 351 CID


49
Ford Galaxie, 400 CID


General Motors, 5,000 IW
350 CID, EG!50

General Motors 5,000 IW,
350 CID, EGR?0





British Leyland, Austin
Marina^l

British Leyland , Austin
Marina ^ 1
British Leyland, Austin
Marina-* 1

52
Nissan, 119 CID, Datsun
2750 IW


52
Nissan, 119 CID, Datsun
2750 IW

53
Toyota, 2,500 IW, 1.6 liter

Mileage
0
9,000

0
10,000
22,000

0
8,000
125000

0
3,000

0
8,000
12,000
16,000
20,000
24,000
0
6,740
10,720
0
10,875

0
6,600
0
4,600
11,700
20,700

0
11,800
18,300

0
5,000
HC
0.8
1.2

0,7
0.7
1.0

0.6
1.0
1.2

0.36
0.41

0.31
0.38
0.94
0.84
0.66
0.8
0.39
0.53
0.58
0.15
0.38

0.19
0.36
0.09
0.27
0.30
0.39

0.21
0.33
0.57

0.11
0.17
CO
2.9
6.2

3.0
3.4
7.0

0.9
1.5
2.0

1.9
2.4

2.8
3.4
4.4
7.6
3.4
6.8
1.32
1.71
1.7
0.67
L.8

2.49
1.51
1.08
0.73
0.93
1.67

1.38
1.1
4,07

1.89
1.12
MOX
0.6
0.7

0.7
0.8
1.0

0.4
0.5
0.7

0,41
0.56

0.24
0.24
0.38
0.34
0.36
0.36
0.29
0.27
0.64
0.45
0.85

0.35
0.23
0.33
0.39
0.48
0.68

0.30
0,31
0.39

0.43
0.49

-------
     1.0r-
O
                 4,000
8,000
12,000         16,000
     AM A Miles
20,000
24,000
28,000
FIGURE  7.1   Durability Data  on General Motors' KOX Catalysts.  Emission Durability
Test Results,  Dual Catalyst  Emission Control Systems.   1975 Federal Test  Procedure.
                                                                                                          OC3
Source:  Reference 50

-------
                                   69
   1.0



   0.8



f 0.6
O  0.4
   0.2



     0
                            1975 FTP BAG DATA
    10 i—
O
O
   1.0



   0.8



1  0.6
OJ


I  0.4



   0.2



    0
I     I
                       TUNEUP
     0    4     8    12   16    20    24    28   32   36   40   44   48

                          AMA MILEAGE IN THOUSANDS

FIGURE  7.2   AMA. Durability Test  Oxidising and Reducing Catalyst.
Source:   Reference 50

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                                         TABLE 7.2a

                                     Prototype
                       1977 Dual Catalyst Systern Performance
                    350 GIB, 5,000 Ib  , EGR, Air,  '75 FTP, Low Mileage
Sy^atejn
NO
HC
CO
NO
MPG
De ve 1 opmen ta 1
                  0.33
             2,5
             0.35
             11.8
                                            0.26/0.37     2.0/3,2       0.3/0.45      11.4/12.1
Durability
15
0.30
2,1
0.28
10.1
                                            0.17/0.48     1.1/3.8       0.19/0.35     8.7/12.4

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                                    TABLE  7.2b

                                   18 Car  Fleet
                       1977 DLLS! ^Catalyst -System-Performance
                       350 CID,  5000 ib  ,  EGR, Air,  '75 FTP
                       A/F - 14/1
System
Manifold + U.F.
No,
12
Ay_g._ Mileage     HC
    231
                                                              CO
                                                            MPG
0.36        1.9      0.41       8,5
0.33/0.39   1.2/2,9  0.30/0,51  7.8/9.9
                                   3091
                            0.41
                             2,4
                     0.56
           9.5
Manifold
               314
                 0.29
            2.3
0.58
9.3
                                                  0.25/0,33    1.9/3.0   0.52/0.64  8.2/10.3

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                                   72
vehicles.  Durability results are not as encouraging for large cars
with higher engine NO  emissions.  The cause for the rapid decrease
                     •A
in NO  converter efficiency with mileage accumulation is not well
     x
understood; how much is due to earburetion problems, or to poisoning
or overteiaperature is not precisely known.*
       It appears that the amount of work and effort being performed
on the dual-catalyst approach by the major manufacturers is somewhat
diminished over that of two years ago.  This may be due either to
effort being pursued on other, more promising systems, or to a
decision to wait with the expectation that alternate standards for
NO  will be legislated.
  /c
       Other approaches involving the use of a reduction catalyst
are being worked on by Gould and Questor.  Each of these systems is
designed to carefully control the CO/0  ratio to the NO  catalyst.  In
                                      •£.                X
the Gould system, an 0  getter is used upstream of the reduction
catalyst.  In the current Gould configuration, the getter consists of
a small, noble-metal oxidation catalyst.  The getter is located in the
same can as the metallic nickel-based NO  converter, with an oxidation
                                        X
catalyst located downstream.  The getter lowers the 0,. concentration
entering the NO  bed to approximately 0.1% over the range of operating
               X
conditions experienced in the CVS test  (Figure 7.3).  This would then
compensate for the variabilities associated with today's conventional
carburetors.  The latest Gould reduction catalyst (GEM 68) gives over
90% next SO  conversion (Fig. 7,4) when operating at 1250 F over a
range of CO/0  of 2 to 6 (corresponding to A/F ratio of 14.2:12.7).
Eesults of this system are given in Table 7.4.
       To reduce HC levels to 0.41 g/mi, it would be necessary either
to use a larger or improved oxidation catalyst or to improve
•'•'To overcome problems associated with carburetor variability, GM has
run a dual-catalyst system with feedback control featuring  an  oxygen
sensor and variable  Venturi carburetor (Table 7,3).

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                                 TABLE  7,3


                     1977 Dual Catalyst - Closed  Loop
                     	System Performance	^^

                   350 CID,  5,000 LB Inertia  Weight with
               Oxygen Sensor and Variable Venturi Carburetor
                    Low Mileage (Average of Two  Tests)
HC                           CO                  NO                   MPG
                                                   -
0.27                         0.83                0,25                  11.9

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                                 74
    8.35


    7.00


    5.72
o

O  3.55
£

O  2.68
o


o  2.20
1-

g  1.88

LU

°-  1.20


   0,55


   0.00
                           GETTER OUTLET
                                 TIME
                               TiME
                                                              5.0
                                                             4.0
                                                                  33
                                                                  o
                                                              3.0  O
                                                                  X
                                                              2.0
                                                              1.0
                                                              0.0
                                                              0.0
FIGURE  7.3  Effect  of Getter on  Inlet CO and  02 During Portion
of CVS  Test.  Test  Conducted on  351 CID Ford  Torino, Automatic

Transmissions
Source:   Reference  54

-------
  C/3
  QC
  o
  CJ
    X
  o
     90
      80
      70
      60
  o
  
-------
                                     76
                                 TABLE 7.4
          Vehicle



 73  Datsun 610, IW 2,500 Ibs.



 No  EGR, Manual Transmission



    Test at Gould
          Net NO
                x

          Conversion

Mileage   Efficiency   CO   NOX   HC*
                     3.149  0.354



                     1.917  0.356



                     1.906  0,384
5,600
10,249
15,381
85.2
86.0
84.5
                                25,580      85.5    3.18   0.382



      *HC were measured incorrectly and are not included.
Same, Test at EPA   after



  25,580 miles



Average of 3 tests
                                               HC
                       CO   NOX   Economy
               0.98   2.93  0.41   21.5 MP
                                                           REF.  55

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                                    77
carburetion.  Both approaches are now being pursued by Gould.
       Preliminary results with the Gould system on a large ear3 1971
Ford Torino, indicate NO  levels of approximately 0.6 g/mi up to
                        A
25,000 miles, with no EGR.  Fuel economy of the large car was
equivalent to that of a 1973 model.  Gould's experimentation to date
has been with stock vehicles, retaining timing while resetting the
carburetors to give the desired rich carburetion.  It would appear
that if this system were  to be applied to a 1975 vehicle with timing
and other adjustments for optimum economy, some improvements in
economy would be attained.  Conservatively, it would appear that
levels of 0,4/3.4/1.0 in  standard vehicles could be realized with
economy no worse than 5%-10% beloxtf 1975 catalyst vehicles.  For
small cars, 0.41/3.4/0.4  could be attained with the Gould system with
economy approximately the same as 1975 models of the same weight.
       With the Questor approach, the ratio of CO/0  going to the NO
converter is controlled with a rich thermal reactor instead of a
getter.  Thus,the Questor system consists of a rich thermal reactor5
followed by a metallic, nickel-based NO  converter, followed by
                                       X
another thermal reactor for cleanup of HC and CO.  Controlled air
is injected into the exhaust ports and before the final oxidizing
thermal reactor.  Durability tests of the Questor system are shown
in Table 7.5.  Fuel economy was 8.2 mpg, about 14% worse than EPA
results for average 1974  vehicles in the 5,000-pound weight class.
       Questor is currently testing a newer, more durable reduction
catalyst which will enable leaner operation (although still on the
rich side of stoichiometric).  Results on a Datsun tested at 2,750-
pound inertia weight gave> at 8,103 miles:

                     HC          0.16
                     CO          2.97
                     NO          0.28
                       x

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                       78






                   TABLE 7.5






Questor System on 1971, 400 CID Pontlac Catalina.






Mileage           HC      CO     NOX        Comments




     0          0.085    3.03    0.365




18,483          0.400    2.66    0.380




23,142          0.235    1.56    0,617    NO  catalyst replaced




35,946          0.158    3.045   0.419




50,024          0.294    2.986   0.283
                                              REP. 56

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                                    79
Economy here was L8.2 mpg, about equivalent to that of the average
1974 vehicle in that class.
       It is felt that improved carburetion could help economy of
both the Gould and Questor systems.  Both systems appear capable of
being certified at levels below 0.41/3.4/1,0,

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                  8.  THIEE-WAY CATALYST WITH FEEDBACK
8.1  Introd nc t ion
     Under carefully controlled conditions, a single-bed catalyst  is
able to reduce all three automotive emissions, HC, GO and NO  ,  to
levels of 0,41, 3.4 and 0.4 g/mi, respectively.  Current three-way
catalysts of this type must be operated with the engine close to
stoichiometric, as shown in Figure 8.1.    Control to within +0,1
A/F ratio is required for successful operation.  With the successful
development of the 0  sensor and feedback control, which allows the
required A/F ratio control (Section 5) intensive efforts are underway
to develop a three-way catalyst with the required durability.  This
three-way catalyst system with feedback has several advantages over
a dual catalyst system:  with only one catalyst, the problem of
catalyst warm-up and cold-start emissions is alleviated; operation
at stoichiometric rather than fuel-rich leads to improved fuel
economy;  no air pump is required since enough  0  is present in the
exhaust stream;  and, feedback control at stoichiometric provides a
self-maintaining feature,  compensating for minor variations in
engine parameters.
^'2  Three-Way Catalyst with Electronic Fuel Injection (EFI)
     and__Fee d b a c k
     Many manufacturers haw been able to achieve 1978 levels at
low mile age', using the Q  sensor feedback and L-jetronie fuel
                                                   58
injection.   Typical results are shown in Table 8.1.
                                   80

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                        81
  100
   40
      Rich
       14.5    150     15.5  Lean
AIR/FUEL RATIO
FIGURE 8.1  Conversion Efficiency of a  Three-
Constituent Catalyst.
Source:  Reference  57

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                                    82
                                TABLE 8.1
     Volkswagen
     Bosch
     Daimler -Ben;:
                          HC
     CO
                                              x
0.3
0.3
0.4
1.2
1.7
1.8
0.2
0.3
0.4
                    4 cylinder,  1.9  liter
                    8 cylinder,  4.8  liter
     Robert Bosch has the most advanced durability results and claims
that 20,000-mile durability has been demonstrated with a 2,300 Ib car
and 1.9 liter engine with the values shown in Figure 8.2.   After that
period, the NO  emissions started to rise for unknown reasons.  Bosch
              x
also made the claim, based on the results of bench tests (Figure 8.3),
that better catalysts are now available and that durability of
25,000 miles or more will soon be demonstrated.   The data  of Figure
8.2 were obtained with the catalyst dated 10/10/73 in Figure 8.3;
                                                              59
the catalyst dated 4/2/74 clearly exhibits better performance.
       Ford   has been experimenting with an in-house developed
EFI system and 0  feedback with the following results for  a fresh
catalyst:
                              HC
         CO
           Feed gas           2.9      22
           After catalyst     0.1      2.0
           No EGR
               and for aged catalyst (100 hrs)
           NO
           	x
           4.2
           0.5
           Feed gas
           After Catalyst
           No EGR
HC
3.18
0.11
CO
24
0.68
HO
	x
5.0
1.34
           Life  tests  continue.

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                   83
   0,4
                    A
 en
O 0.2
10,000
                        20,000 25,000
   3.4
O
O
   0.4
 x
O
   0.2
                             25,000

FIGURE 8,2   ^-Cylinder Engine,
i.9 Liter,  L-Jetronic, DeGussa  OM721,
Fuel Economy 18.7 mpg, Weight of
Car 1050 kg.
Source:  Reference 59

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                                     84
   600
   400
Q.

O
   200
                                                     10.10,73
                                                   4.2.74
      0         100
200        300
        TiME (hours)
                                                 400        500
600
    0.61—
                                18.6.73
O
                                                    10,10,73   		
                                                         4,2,74
      0         100
200
                                      300        4 00
                                   TiME (hours)
FIGURE  8.3   Catalyst Durability.
                                                            500         600
Source:   Reference 59

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                                  85
                             TABLE 8.2
a.  Vega EFI Emission and Economy Results  (Low Mileage)
             3000 Ib I.W.
                                EC          CO          NO
                                                          x
Average of 5 emissions tests:   0.23 g/mi   2.58 g/mi   0.32 g/mi
Fuel Economy:     20.43 mpg @ 0.35 g/mi  ^- NO  (EGR)
                  21.42 mpg @ 0.90 g/mi  #=- NOr(No EGR)
                                              x
Base:    20.50 mpg for  '75 Calif. @ 1,4 NO
                                          X
         20.32 mpg for  '75 Federal @ 2.1 NO
                                           x
b.  Chevrolet 350 C.I.D., V8, 4,500 Ib  I.W.  (Low Mileage)
                                                        MPG
HC

0.56
0.47
CO

5.1
4.6
NO
x
0,96
0,77
                                                        11.5
                                                        Not available
                                                                 REF. 57

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                                 86
                             TABLE 8,3
       Comparison of Various Control Schemes (1.9 L Engine)
                 AH Cars Equipped with L-Jetronic
             Car 1
                  Car 2
                Car 3*
                                                             Car 4*
Stoichio-
tnetric
Ratio

Spark Advance

Percent EGR

1975 Model
1.05
O
4

3-10

Lean
1.15-1.2
o
8
Double ignition
8

Lean
1.04
o
8

8


1.0
o
4 delay

0
*Cars 3 and 4 have feedback control
HC
0.57
0.15
0.2
0.15
CO
6.67
2.9
3.02
1,72
NO
1,59
0.88
1.16
0.13
Fuel Cons,      100%
                  121%
                100%
              89%

-------
                                   8?
     General Motors   provided data on a Vega equipped with a three-
way catalyst, EFI and feedback as shown in Table 8,2.
     Most manufacturers agree that fuel economy of the 0  sensor -
L-jetronic feedback control is improved over open-loop controls and
that 1978 standards can be met with minimum fuel penalty If the three-
way catalyst aging problem is resolved.
     Bosch provides an interesting comparison of various control
systems in Table 8.3.  The superiority of feedback is evident.
8.3  Three-Way Catalyst with Mechanical Fuel Injection (MFI)
     and Feedback
     The 0  sensor output requires the addition of a simple electronic
control unit and an additional solenoid-operated fuel pump to
modulate fuel pressure in the control pressure loop of the K-jetronic
mechanical fuel injection device.  The 0  sensor feedback system with
K-jetronic now becomes somewhat more expensive than the equivalent
L-jetronic feedback control.
     Many manufacturers report that they were able to achieve 1978
MO  standards at low mileage; however, failure occurred because
  jC
of three-way catalyst aging after less than 10,000 miles.  Typical
results are shown in Table 8.4 .




Saab
Audi
Volvo


HC

0.1
0.28
0.25

Table
CO

1.7
1.0
0.8
58
8.4
NO
X
0.21
0.4
0.25


MPG

19.3

16.0
     No durability data is available.
     No U.S. manufacturer reported data with the K-jetronic feedback
     system.

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                                   88
8.4  Three-Way Catalyst with Carburetor andFeedback
     All U.S. manufacturers and some foreign carburetor manufacturers
are developing carburetors whose settings can be continuously
adjusted with electrical error signals from an exhaust gas sensor.
Most electronic carburetors are of the variable Venturi category
although some work is reported with sonic carburetion.  This approach
ia logical since feedback control makes sense only with better
cylinder-to-cylinder distribution than can be achieved with conventional
carburetors.  W carburetors,  sonic carburetors, and hot-spot
carburetors can provide the needed improved A/F ratio distribution.
     Results from GM with advanced design carburetors, feedback and
the three-way catalyst are given in Table 8,5   (all at low mileage).

                            TABLE 8,5
     Car                 Carburetor    HC    CO    NO     MPG
                                                     x
4000 I.W.,  V8            Mod.  Quad     0.28  4,85   0.54   11.7
4500 I.W.,  V8,  350 CID   IFC           0.17  5.5   0.69   11,5

     To summarize;
     In all cases,  fuel economy of three-way catalyst systems is  good,
     as is  driveability.   Fuel economy could be improved  further  by
     the complete  elimination  of EGR;  this may  not be possible with
     the large  U.S.  engines.
    The durability of the 0?  sensor  is established;  the  durability of
     the three-way  catalyst is not proven and cannot  be predicted.
    The tests  of  Bosch suggest,  however,  that  a durable  catalyst
    may be  achievable.

-------
                               89
The cost of feedback control systems may be attractive in
comparison with more conventional systems because of possible
elimination of many presently used ancillary controls such as
fast chokes, altitude compensation, air pumps, EGR, etc.
The feedback Control is a new technology with great potential
to achieve low emissions with low fuel consumption and
control-system cost.

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                        9,  ROTARY ENGINES
9.1  In t r o du c tion
     The chief advantages of the rotary engine as an automotive power
plant lie in its smoother operation fewer number of parts and
higher power-to-weight ratio, in comparison to a conventional piston
engine.  However, the engine has a high surface-to-volume ratio,
contributing to higher HC emissions and lower thermal efficiencies
in comparison to equivalent piston engines.  Bare-engine HC emission
levels of current rotary engines are approximately four times those
of equivalent piston engines, whereas CO and NO  levels are roughly
the same as those of piston engines,
     The emissions-control system used on 1974- Mazda rotary engines
featured a rich exhaust thermal reactor to control HC emissions, with
the engine operating at an air fuel ratio of approximately 13:1,
Exhaust emissions measured in 1974 California certification by EPA.
are given in Table 9.1, as well as data from Toyo Kogyo on the same
model.
     Because of the above-cited problem with high HC emissions and
high fuel consumption, there does not appear to be a concerted
movement in the industry towards rotary engines.  Though a few
manufacturers have increased their efforts on rotary engines, most of
the increased effort has gone into feasibility studies.  Ford has
terminated such a feasibility study during the past year.

9.2  Near-Term Systems
     Emissions-control systems currently used on rotary engines are
similar to those used on conventional piston engines; namely,
catalysts or thermal reactors and EGR.   There is some concern about
the durability of the catalyst-equipped systems since the HC loading
is so much higher than that of conventional engines.  Figure 9.1
illustrates this problem.   With base-engine em ssions of 8-10 g/mi
HC catalytic converter efficiencies of approximately 90% are required
                                  90

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                             91






                          TABLE 9.1






Exhaust Emissions of the 1974 Mazda with Etch Thermal Reactor






                                        HC     CO     NO      MPG
                                                        x


 1974 California EPA certification      2.4    19     0.9     10.4



 1974 Production average                2.5    14     1.3     11.8






                       3,000 Ib inertia weight



                       Engine displacement 80 CID



                       Manual transmission
                                                      KEFS. 61,62

-------
                           92
    100
>    90
o
LL
LL
LU
2
o

DC
LU
>

%   80
      0      2       4       6       8      10      12

                BARE ENGINE EMISSIONS (g/mij

FIGURE 9.1   HC  Conversion Efficiency Requirements,
Source:  Reference 63

-------
                                   93
to achieve exhaust HC levels of 0.90 g/mi (California interim 1975
level).  There is clearly little margin for deterioration.
     Thermal reactor systems do not appear to have this problem;
deterioration factors for these systems are shown in Table 9.2.
However, the rich reactors currently in use incur a fuel penalty,
as was shown in Table 9.1,  A summary of results from General Motors
is given in Table 9.3.  It can be seen that, at least at low mileage,
fuel economy of catalyst-equipped rotary engines approaches that of
equivalent 1975 vehicles equipped with conventional engines.
     Toyo Kogyo is developing a lean-reactor system.   This system
uses an A/F ratio of 16.5:1 to 17:1.  Results are shown in Table 9.4,

9.3  Long-Term Systems
     Some work is being done on more advanced rotary engines systems.
Most of this effort is being spent on adapting the stratified-charge
concepts to the rotary engine.  Both open-chamber and divided-chamber
concepts have been tried with reasonable results.   Table 9.5 shows
the outcome of some of this work.
     Figure 9.2 shows the relationship between NO  level and fuel
                                                 J±
consumption for a typical present rotary-engine powered vehicle and
similar stratified-charge rotary-engine vehicles.   Although a
significant fuel-consumption improvement is made using the
stratified-charge principles, the basic relationship between NO
                                                               3C
level and fuel consumption holds.  Whenever lower NO  levels are
approached, the driveability is seriously impaired even with the
stratified-charge systems.
     Although the stratified-charge work has shown promising results,
it is still in the early stages of development.  Also, some type of
external clean-up device (i.e., thermal reactor, catalyst, etc.) is
still needed to achieve the emissions standards although the bare-

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                               94


                           TABLE 9.2
               Typical Deterioration Factors of


            Thermal Reactor-Eqiiijjpeji jlotary Engines
Pollutant                      Deterioration Factor
    HC                               1.0 - 1.05
    CO                               L.O - 1.03
    HO                               1.02-1.05
      x

-------
                                         TABLE 9.3
                                      Emissions Summary
            System
  Tail Pipe
HC    CO     NOx
  Base Engine
 HC    CO    NOx
   EPA
   MEG
350 V-8 -- 260 Cu. In, U'Floor
              f f\
Bead Converter
0,29  1,88   2,3
 2.7   8.4   2.3
GMRE -- 260 Cu. In. U'Floor
              f T-\
Bead Converter
0.60  1.2    2.6
10.9   8.1   2.4
15.0/15.5
GM RE, U'Floor & Warm-Up Conv.
GM RE, Reactor/Conv. System
0,30  4.6    1.5
0.40  2.5    2.1
10.7  21.5   1.3
 3.3  14.5   2.1
15,0/15.5

14.3
GM RE, Reactor Only
0,46  6.6    1.7
1 - low mileage
2 - 4,000 Ib weight class
3 - 3,500 Ib weight class
4 - Base engine values were measured at the reactor outlet
                       12.4
                                                                              REF.   63 , 64

-------
                                         TABLE 9.4
                                Rotary with Lean Reactor

           Emission Target         Actual Emissions        Fuel Economy       No.  of
           (HC, CO, NO , g/mi)     (CO, HC, NO , g/mi)         mpg            Tests
No EGR         0.9/9/2.0              4.8/0.38/1.7            17.0


No EGR         0.41/3,4/2,0           2,0/0.18/1.?            16.4



EG!                                   2,4/0.21/0.85           15,3



EGR                                   2,3/0,27/0.74           15.1



            I.¥.   = 3,000 Ibs,

            Manual Transmission

            Engine displacement 80 C.I.D.
                                                                           REF.  62

-------
                                  97
                              TABLE 9.5
         Emission and Fuel Consumption Characteristics of an


      Experimental Open-Chamber Stratified-Charge Rotary Engine
EGR (%)                      0           7-8%          20V




HC (g/mi)                    0.24        0.22




CO (g/mi)                    1.8         2.5




NO  (g/mi)                   L.5         0.91          0.4
  x



Fuel Consumption (ropg)      17.5        L6.8          14.0
* Bench data only
                                                         REF. 64

-------
    2.0
_   1.5
    1,0
   0.5
                               98
                             • Present System (1973-1974 Mazda)

                             • Open-Chamber Stratified Chsrge-j

                             A Divided-Chamber Stratified Chgrge-j
     18      17      16      15      14      13     12

                       FUEL CONSUMPTION (mpg)
11
FIGURE 9.2   Comparison of  NOX and Fuel  Consumption
Characteristics of  Various Rotary Engine Concepts.
10
Source:  References 62,  63

-------
                                 99
engine emissions are undoubtedly lower.  It is doubtful if a fully
developed stratified-charge rotary-engine could be available before
the early to middle 1980fs.

9.4  Summary
     Most of the rotary-engine effort to date has been concentrated
on improving durability and fuel consumption.  Little effort has
been spent on understanding the basic combustion process or lowering
the bare-engine emissions.  Most manufacturers appear to be looking
at the rotary engine for its packaging, performance and potential
cost advantages rather than as a solution to the emissions problem.
     It appears that rotary-engine systems can meet near-term emissions
standards with reasonable fuel consumption.   Although the advanced
stratified-charge rotary-engine concepts appear promising, it is
doubtful whether they can be available until the 1980's.

-------
                  10,  STEATIFIED-CHARGE ENGINES


10.1  Introduction and General Background
      a.  General — The term "stratified-charge engine" has been
used for many years in connection with a variety of unconventional
engine combustion systems.  Common to nearly all such systems  is
the combustion of F/A mixtures having a significant gradation  or
stratification in fuel concentration within the engine combustion
chamber.  Hence the term "stratified charge."  Historically, the
objective of stratified-charge-engine designs has been to permit
spark-ignition-engine operation with average or overall F/A. ratios
lean, beyond the ignition limits of conventional combustion systems.
The advantages of this type of operation will be enumerated shortly.
Attempts at achieving this objective date back to the first or
second decade of this century,
          More recently,  the stratified-charge engine has been
recognized as a potential means for control of vehicle pollutant
emissions with minimum loss of fuel economy.  As a consequence, the
various stratified-charge concepts have been the focus of renewed
interest.
      b.   Advantages and  disadvantages o_£_ lean-mixture operation —
Fuel-lean combustion as achieved in a number of the stratified-charge-
engine designs receiving  current attention has both advantages and
disadvantages when considered from the combined standpoints of
emissions control,  vehicle performance and fuel economy.
          Advantages of lean mixture operation include the following:
      Excess  oxygen contained in lean-mixture combustion gases help
      to  promote  complete oxidation of hydrocarbons (HC)  and carbon
      monoxide (CO)  both  in the engine cylinder and in the exhaust
      system.
                                  100

-------
                                 101
,      Lean-mixture combustion results in reduced peak engine-cycle
      temperatures and can, therefore, yield lowered nitrogen oxide
      (NO ) emissions.
         x
      Thermodynamic properties of lean-mixture-eombustion products
      are favorable from the standpoint of engine-cycle thermal
      efficiency (reduced extent of dissociation and higher effective
      specific heats ratio),
      Lean-mixture operation can reduce or eliminate the need for air
      throttling as a means of engine load control.   The consequent
      reduction in pumping losses can result in significantly
      improved part-load fuel economy.
          Disadvantages of lean mixture operation include the
following:
*      Relatively low-combustion gas temperatures during the engine
      cycle expansion and exhaust processes can result from extreme-
      ly lean operation.  As a consequence, HC  oxidation reactions are
      retarded and unburned HC exhaust emissions can be excessive,
      Engine modifications aimed at raising exhaust  temperatures for
      improved HC emissions control (retarded ignition timing,  lowered
      compression ratio, protracted combustion) necessarily impair
      engine fuel economy.
      If lean-mixture operation is to be maintained  over the entire
      engine load range, maximum power output and, hence,  vehicle
      performance are significantly impaired.
      Lean-mixture exhaust gases are not amenable to treatment  by
      existing reducing catalysts for NO  emissions  control.
                                        "

-------
                                  102
      Lean-mixture combustion, if not carefully controlled, can
      result in formation of undesirable odorant materials that appear
      in significant concentrations in the engine exhaust.  Diesel
      exhaust odor is typical of this problem and is thought to derive
      from lean-mixture regions of the combustion chamber,
      Measures required for control of NO  emissions to low levels
      (for example, EGR) can accentuate the above HC and odorant
      emissions problems.
          Successful development of the several stratified-charge-
engine designs now receiving serious attention will depend very much
on the balance that can be achieved among the foregoing favorable
and unfavorable features of lean combustion.  This balance will, of
course, depend ultimately on. the standards or goals that are set for
emissions control, fuel economy, vehicle performance and cost.  Of
particular importance are the relationships between three factors--
unburned hydrocarbon (UBHC) emissions,, NO  emissions, and fuel
                                         rf»
economy.
      e.  Stratifled-.charge-eng ine concepts — Charge stratification
permitting lean-mixture operation has been achieved in a number of
ways using differing concepts and design configurations.
          Irrespective of the means used for achieving charge
stratification, two distinct types of combustion processes can be
identified.  One approach involves ignition of a small and localized
quantity of flammable mixture which, in turn, serves to ignite a
much larger quantity of adjoining or surrounding fuel-lean-mixture—
too lean for ignition under normal circumstances.  Requisite mixture
stratification has been achieved in several different ways ranging
from use of fuel injection directly into "open" combustion chambers
to use of dual combustion chambers divided physically into rich and
lean-mixture regions.  Under most operating conditions, the overall

-------
                                   103
or average P/A ratio is fuel-lean and  the advantages enumerated above
for lean operation can be realized,
          A second approach involves timed staging of  the combustion
process.  An initial rich-mixture stage in which major combustion
reactions are completed is followed by rapid mixing of rich-mixture
combustion products with an excess of  air.  Mixing and the resultant
temperature reduction can, in principle, occur so rapidly that
minimum opportunity for NO formation exists and, as a consequence,
NO  emissions are low.  Sufficient excess air is made available to
  x
encourage complete oxidation of HC and CO in the engine cylinder and
exhaust system.  The staged combustion concept has been specifically
exploited in divided-chamber or large-volume prechamber engine
designs.  But it will be seen that staging is also inherent to some
degree in other types of stratified-eharge engines.
          The foregoing would indicate that stratified-charge engines
can be categorized either as "lean-burn" engines or "staged-combustion"
engines.  In reality, the division between concepts is not so clear
cut.  Many engines encompass features of both concepts.
      d.  Scope -- During the past several years, a large number of
engine designs falling into the broad category of stratified-charge
engines have been proposed.  Many of these have been evaluated by
competent organizations and have been found lacing in one or more
important areas,  A much smaller number of stratificd-charge engine
designs have shoxm promise for improved emissions control and fuel
economy with acceptable performance, durability and production
feasibility.   These are currently receiving intensive research
and/or development efforts by major organizations — both domestic
and foreign.
          The purpose of this Consultant Report is not to enumerate
and describe  the many variations of stratified-charge engine design
that have been proposed in recent years.   Rather, it is intended to

-------
                                    104
 focus on those engines that are receiving serious development efforts
 and for which a reasonably large and sound body of experimental data
 has evolved.   It is hoped that this approach will lead to a reliable
 appraisal of  the potential for stratlfied-charge engine systems.

 10.2  Open-Chamber., Stratified-Charge Engines
       a.  General -- From the standpoint of mechanical design,
 stratified-charge engines can be conveniently divided  into two  types:
 open-chamber  and dual-chamber.   The open-chamber,  stratified-charge
 engine has a  long history of  research interest.   Those engines
 reaching the  most advanced stages  of development are probably the
 Ford-programmed  combustion process  (PROCO)   J    and Texaco's
 controlled combustion process  (TCCS),   '     Both engines  employ  a
 combination of inlet air  swirl  and  direct  timed  combustion-chamber
 fuel  injection to achieve a local  fuel-rich ignitable  mixture near
 the point  of  ignition.  For both engines,  the  overall  mixture ratio
 under  most  operating conditions  is  fuel  lean,
          Aside  from these  general  design  features that are common  to
 the two  engines,  details  of their respective engine-cycle  processes
 are quite  different,  and  these differences  affect engine  performance
 and emissions  characteristics,
       b.  The Ford PROCO  engine
           (1)   Descriptions -- The Ford PROCO engine is an outgrowth
of  a stratified-charge development program  initiated by Ford  in  the
late 1950's.  The development objective at  that  time was  an engine
having diesel-like fuel economy but with performance,  noise levels,
and driveability comparable to that of conventional engines.  In the
1960's, objectives were broadened to include exhaust-emissions
control.

-------
                                  105
               A recent developmental version of the PROGO engine
is shown in Figure 10-1.  Fuel is injected directly into the
combustion chamber during the compression stroke resulting in
vaporization and formation of a rich mixture cloud or kernel in the
immediate vicinity of the spark plug(s).  A flame initiated in this
rich-mixture region propagates outwardly Co the increasingly fuel-
lean regions of the chamber.  At the      time, high air-swirl
velocities resulting from special orientation of the air inlet system
help to promote rapid mixing of fuel-rich combustion products with
excess air contained in the lean region.  Air swirl is augmented by
the "squish" action of the piston as it approaches the combustion-
chamber roof at the end of the compression stroke.  The effect of
rapid mixing can be viewed as promoting a second stage of combustion
in which rich mixture-zone products mix with air contained in lean
regions.  Charge stratification permits operation with very lean F/A
mixtures with attendant fuel economy and emissions advantages.  In
addition, charge stratification and direct fuel injection permit use
of high compression ratios with, gasolines of moderate octane quality -
again giving a substantial fuel economy advantage.
               Present engine operation includes enrichment under
maximum power-demand conditions to mixture ratios richer than
stoicMometrie.  Performance, therefore, closely matches that of
conventionally powered vehicles.
               Nearly all PROCO development plans at the present time
include use of oxidizing catalysts for HC emissions control.  For a
given HC emissions standard, oxidizing catalysts permit use of leaner
A/F ratios  (lower exhaust temperatures) together with fuel injection
and ignition timing characteristics optimized  for improved fuel
economy.
           (2)  Emissions and fuel economy -- Figure 10-2 is a plot
of P10CO vehicle fuel economy versus NO  emissions based on the

-------
                      106
                                       Fuel Injector
Spark Plug
 FIGURE 10.I  Ford PRQCO Engine.
 Source:  Reference 71

-------
    15 (—
    14 —
             i-i--^:>":-l:i;!:\-^i--'>^;:':!;:: NOX vs- Fuel Economy with
             •;'";-::::S::V'v:-^';::-:":fe No HC Restriction
                            HC Excessive
Q.
E
~ 13
o
LO
>
LJ
j>
o 12
o
LU
_(
LU
£ 11


10
/^" W/EGR >
— Approx. 1 jS
Correct * .S
to } 4 S
5000 Ib 1 f jS
T7S

S
—
1974 Pr
Ecorsorn
I II
                                                                      HC-1.4
                                                                      CO-7,1
                                                                             Catalyst Feed
                                                             HC- 1.7
                                                             CO-12,7
                                                                      Catalyst Feed
                                                                           351 CIO, 5000 Ib inertia Weight

                                                                           "100 C1D, 5000 Ib Inertia Weight

                                                                           351 CID, 4 500 Ib Inertia Weight
                                      19/4 Production Average Fuel
                                                                  4500 Ib  :
!•>:•:•:•>:•:-:-:-:-:-:•:•:•:•:•:•:•:•:•:•:•:•:•:-:•
;•.•:•:•:-.•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:•:
1 1

:•,-,', •,',•,'.•,'.•.-.-,-.•.-.-.•.:
v-:-;-;:-:-:-;-:-:-:-:-:-:-:-:-:-:
            0                            1.0                            2,0

                                           NOx EMISSIONS, CVS CH {g/mi)

FIGURE 10.2   Ford  PROCO  Engine Fuel  Economy  and  Emissions.
                                                                                                       3.0
Source:   References  70,  71

-------
                                  108
Federal CVS-CH test procedure.  Also included are corresponding HC
and CO emissions levels.  Only the most recent test daCa have been
plotted since these are most representative of current program
directions and also reflect most accurately current emphasis on
improved vehicle fuel economy.  '    For purposes of comparison,
average fuel economies for 1974 production vehicles weighing 4,500
                                          72
pounds and 5,000 pounds have been plotted.    (The CVS-C values
reported in Reference 72 have been adjusted by 57, to obtain estimated
CVS-CH values.)
              Data points to the left on Figure 10-2 at the 0.4 g/mi
NO  level represent efforts to achieve statutory 1977 emissions
  X    70
levels.    While the NO  target of 0.4 g/mi was met, the requisite
                       x
use of EGR resulted in HC emissions above the statutory level.
               A redefined NO  target of 2.0 g/mi has resulted in
                             x
the recent data points appearing in the upper right-hand region of
Figure 10-2.    The HC and CO emissions values listed are without
exhaust oxidation catalysts.   Assuming catalyst conversion
efficiencies of 50%-607o at the end of 50,000 miles of operation, HC
and CO levels will approach but not meet statutory levels.  At the
indicated levels of emissions-control fuel economy is improved some
40% to 45% relative to 1974 production-vehicle averages for the same
weight class.
               The cross-hatched,  horizontal band appearing across
the upper part of Figure 10-2 represents the reductions in NO
emissions achievable with use of EGR is HC emissions are unrestricted.
The statutory 0,4 g/mi Level  can apparently be achieved with this
engine with little or no loss of fuel economy but with significant
increases in HC emissions.   The HC increase is ascribed to the
quenching effect of EGR in lean-mixture regions of the combustion
chamber.

-------
                                   109
          (3)  Fuel requirements — Current P10CO engines operated
with 11:1 compression ratio yield a significant fuel economy
advantage over conventional production engines at current compression
ratios.  According to Ford engineers, Che PROCO engine at this
compression ratio is satisfied by typical full-boiling commercial
gasolines of 91 RON rating.  Conventional engines are limited to
compression ratios of about 8:1 and possibly less for operation on
similar fuels.
               Results of preliminary experiments indicate that the
PROCO engine may be less sensitive to fuel volatility than conventional
engines--an important factor in flexibility from the standpoint of
the fuel supplier.
          (4)  Present status -- Present development objectives are
two-fold:
          Develop calibrations for alternate emissions target levels
          to determine the fuel economy potential associated with
          each level of emissions control.
          Convert engine and auxiliary systems to designs feasible
          for high-volume production,
      c.  The Texaco TCCja _s^tratif ied_~_char£e engine
          (1)  General description -- Like the Ford PROCO engine,
Texaco's TCCS system involves coordinated air swirl and direct
combostion-chamber; fuel injection to achieve charge stratification.
Inlet-port-induced cylinder air swirl rates typically approach ten
times the rotational engine speed,   A sectional view of the TCCS
combustion chamber is shown in Figure 10-3.
               Unlike the PROCO engine,  fuel injection in the TCCS
engine begins very late in the compression stroke -- just before the
desired time of ignition.  As shown in Figure 10-4,  the first portion

-------
Piston
                                   — Shrouded intake Valve
                                              — Fuel Nozzie
                                                     Cylinder Head
                                                    Cylinder Block
                                                                              Fuel Nozzle
                                                                                                             Intake
                                                                                                             Port
Exhaust
Port
                                                                        Horizontal Projections of Nozzle
                                                                        and Spark Plug Centerlines
FIGURE  L0.3   Texaco TCCS Engine,
Source:   Reference 73

-------
                              Ill
      Nozzle
   Spark Plug
 1 - Fuel Spray
 2 - Fuel-Air Mixing Zone
 3 - Flame Front Area
 4 - Combustion Products
FIGURE 10.4   Texaco Controlled  Combustion System,
Source:  Reference  73

-------
                                  112
 of  fuel  injected is Immediately swept by the swirling  air  into  the
 spark  plug  region where ignition occurs and a flame  front  is
 established.  The continuing stream of injected  fuel mixes with
 swirling  air  and is swept  into  the flame region.   In many  respects,
 the Texaco  process resembles the spray burning typical of  diesel
 combustion  with the difference  that ignition is  achieved by energy
 from an electric spark rather than by high compression temperatures,
 The Texaco  engine, like the diesel engine, does  not have a significant
 fuel octane requirement.  Further, use of positive spark ignition
 obviates  fuel cetane requirements characteristic of diesel engines.
 The resultant flexibility of the TCCS engine regarding fuel
 requirements  is a significant attribute.
               In contrast to the TCCS system, Ford's PROCO system
 employs relatively early injection, vaporization, and mixing of fuel
 with air.  The combustion process more closely resembles the
 premixed  flame propagation typical of conventional gasoline engines.
 The PROCO engine,  therefore, has a definite fuel octane requirements
 and cannot be considered a multifuel system,
               The TCCS engine operates with high compression ratios
 and with  little or no inlet air throttling except at idle conditions.
As  a consequence,  fuel economy is excellent—both at full load  and
 under part-load operating conditions,
          (2)  Exhaust emissions and fuel economy -- Low exhaust
 temperatures characteristic of the TCCS system have necessitated use
of exhaust oxidation catalysts for control of HC emissions to low
 levels.  All recent development programs have, therefore, included
use of exhaust oxidation catalysts, and most of the data reported
here represent tests with catalysts installed or with engines tuned
for use with catalysts.
               Figures 10-5 and 10-6 present fuel economy data  at
several exhaust emissions levels for two vehicles--a U.S. Army M-151

-------
      25 —
                                                                             Maximum Economy Setting
                          141 CID, 10:1 CR
                          2500 Ib inertia Weight
                                                                                                1.07 HC
                                                                                                0,84 CO
 O5
 Q.
I
u
o
      24
      23 —
^
o
^
S 22
LLJ

A
— Retard •+
EGR
0.51 HC
0.64 CO
j
X
                                         5-8
                                         Retard
                                               0,73 HC
                                               1,2  CO
                                                  0,61 HC
                                                  0.85 CO
                                                  Retard •+ EBP
      21
      20 —
    0,36 HC
 ^  1.15 CO
Retard + EBP + EGR
             0.4          0,6         0,8          1-0         1.2         1,4

                                          NOX EMISSIONS, CVS-CH (g/mi)

FIGURE  10.5   Texaco  TCCS  Powered  Cricket Vehicle.
                                                                       1.6
2,0
Source:   Reference  73

-------
     25
 en
 O.
 E.

o
>
o
>
s
o
o
o
LU
_t
I—
D
    20
    15 —
                             141 CID, 10:1 CR
                             2750 Ib Inertia Weight
                                                                          ^k   HC—3 1
                                                 Maximum Economy Adjustment      CO-7.0  Catal¥st Feed
                                                           8  Retard
                                                                 A   HC--3.2
                                                                            Catalyst Feed
                                 Low EGR
              Medium EGR
HC-3.6
CO-6.7
                                                Catalyst Feed
                            HC-0.33
                            CO-1.05
            HC-0.35
         4 CO-1.41
            13° Retard
            High EGR
                                                                         5 Retard
                                                                         HC-0.30
                                                1974 Production
                                                Average Fuel Economy
                                                (2750 Ib)
           0.4
     1.0
                                                                                                        2.0
                                          NOX EMISSIONS, CVS-CH (g/mi)

FIGURE  10,6  Turbocharged  Texaco  TCCS, M151  Vehicle.
Source:   Reference 73

-------
                                  115
vehicle with naturally aspirated 4-cylinder TCCS conversion, and a
                                                          73 74
Plymouth Cricket with turbocharged 4-cylinder TCCS engine.  '
Turbocharging has been used to advantage to increase maximum power
output.  Also plotted in these figures are average fuel economies
                                               72
for 1974 production vehicles of similar weight.
               When optimized for maximum fuel economy, the TCCS
vehicles can meet NO  levels of about 2.0 g/mi.  It should be noted
                    x
that these are relatively lightweight vehicles and that increasing
vehicle weight to the 4,000-5,000-pound level could result in
significantly increased NO  emissions.  Figures 10-5 and 10-6 both
                          jC
show that engine modifications for reduced NO  levels including
                                             X
retarded combustion timing, EGR and increased exhaust back pressure
result in substantial fuel economy penalties.
               For the naturally aspirated engine, reducing NO
                                                              X
emissions from the 2,0 g/mi level to 0.4 g/mi incurred a fuel
economy penalty of 20%,.   Reducing NO  from the turbocharged engine
                                    it
from 1,5 g/mi to 0,4 g/mi gave a 25% fuel economy penalty.  Fuel
economies for both engines appear to decrease uniformly as NO
                                                             X
emissions are lowered.
               For the current TCCS systems, most of the fuel
economy penalty associated with emissions control can be ascribed
to control of NO  emissions, although several of the measures used
                x
for NO  control (retarded combustion timing and increased exhaust
      X
back pressure) also help to reduce HC emissions,   HC and CO emissions
are effectively controlled with oxidation catalysts resulting in
relatively minor reductions in engine efficiency.
          (3)  TCCS fuel requirements — The TCCS engine is unique
among stratified-charge  systems in its multifuel  capability.
Successful operation with a number of fuels ranging from gasoline
to No,  2 diesel has been demonstrated.  Table 10-1 lists emissions
levels  and fuel economies obtained with a turbocharged TCCS-powered

-------
                                 116
                                                            74
M-151 vehicle when operated on each of four different fuels.

These fuel encompass wide ranges in gravity, volatility, octane

number and cetane level as shown in Table 10-2,
                            TABLE 10-1
           Emissions and Fuel Economy of Turbocharged


                  TGCS Engine-Powered Vehicle
Emissions

Fuel

Gasoline
JP-4
100-600
Wo. 2 Diesel

EC

0.33
0.26
0.14
0.27
E/mi2
CO

1.04
1.09
0.72
1.14

NO
X
0.61
0.50
0.59
0.60
Fuel Economy
2
mpg

19.7
20.2
21.3
23.0
       vehicle,  8 degrees  combustion retard,  16% light

 load EGRS  two catalysts.


"TVS-CH, 2, 750 pounds inertia weight.
                                                        REP.  74

-------
                                  117
                            TABLE 10-2
                      Fuel Specifications for
                         TCCS Emission Tests
Gasoline
Gravity, °API 58,8
Sulfur, %
Distillation, F
IBP 86
10% 124
50% 233
90% 342
EP 388
TEL, g/gal. 0.002
Research Octane 91.2
Cetane Wo.
100-600
48.6
0.12
110
170
358
544
615
0.002
57
35.6
JP-4
54.1
0.020
136
230
314
459
505
-
-
-
No. 2
Diesel
36.9
0,065
390
435
508
562
594
-
-
48.9 REF. 74
Generally^ the emissions levels were little affected by the wide
variations in fuel properties.  Vehicle fuel economy varied in
proportion to fuel energy content.
               As stated above, the TCCS engine is unique in its
multifuel capability.  The results of Tables 10-1 and 10-2 demonstrate
that the engine has neither significant fuel octane nor cetane
requirements and, further, that it can tolerate wide variations in
fuel volatility.  The flexibility offered by this type of system
could be of major importance in future years.

-------
                                  118
          (4)  Durability, performance, production readiness —
Emissions-control-system durability has been demonstrated by mileage
accumulation tests.  Ignition-system service is more severe than for
conventional engines due to heterogeneity of the F/A mixture and also
to the high compression ratios involved.  The ignition system has
been the subject of intensive development and significant progress in
system reliability has been made,
               A preproduction, prototype engine employing the TCCS
process is now being developed by the Hercules Division of White
Motors Corporation, under contract to the U.S. Army Tank Automotive
Command,  Southwest Research Institute will conduct reliability
tests on the White-developed engines when installed in military
vehicles,

10.3  Small Volume Prechamber Engines (3-Valve. ,.Pr_e; chamber; jSngines,
      Jet Ignition Enginesa Torch Ignition_Engines)
      a.  General — A number of designs achieve charge stratification
through division of the combustion region into two adjacent chambers.
The emissions reduction potential for two types of dual-chamber
engines has been demonstrated.  First, in a design traditionally
called the "preehamber engine," a small auxiliary or ignition chamber
equipped with a spark plug communicates with the much larger main
combustion chamber located in the space above the piston (Figure 10-7).
The prechamber, which typically contains 5%-15% of the total
combustion volume, is supplied with a small quantity of fuel-rich
ignitable F/A mixture while a large quantity of very lean and
normally unignitable mixture is applied to the main chamber above
the piston.   Expansion of high-temperature flame products from the
prechamber leads to ignition and burning of the lean main chamber
F/A charge.   Ignition and combustion in the lean, main-chamber region
are promoted both by the high temperatures of prechamber gases and by

-------
                                  119
      intake
  Prechamber
  (Fuei-Rich Mixture)
Spark P!ug

   Intake
                                                          Exhaust
Main Chamber
(Fuel-Lean Mixture)
FIGURE 10.7  3-Valve  Prechamber Engine Concept.

-------
                                  120
 the mixing  that accompanies the jet-like motion of prechamber  products
 into  the main  chamber.
          Operation with lean overall mixtures tend  to  limit peak
 combustion  temperatures, thus minimizing the formation  of nitric
 oxide.  Further, lean-mixture combustion products contain sufficient
 oxygen  for  complete oxidation of HC and CO in the engine cylinder
 and exhaust system.
          It should be reemphasized here that a traditional problem.
 with  lean mixture engines has been low exhaust temperatures which
 tend  to quench HC oxidation reactions Leading to excessive emissions.
          Control of HC emissions to low levels requires a retarded
 or slowly developing combustion process.  The consequent extension
 of heat release into late portions of the engine cycle  tends to raise
 exhaust gas temperatures, thus promoting complete oxidation of HC
 and CO.
      b.  Historical background and current status
          (1)  Early development objectives and engine  designs — The
 prechamber,  stratified-charge engine has existed in various forms
 for many years.  Early work by Ricardo   indicated that the engine
 could perform very efficiently within a limited range of carefully
 controlled  operating conditions.  Both fuel-injected and carbureted
 prechamber  engines have been built.  A fuel-injected design
 initially conceived by Brodersen   was the subject of extensive
 study at the University of Rochester for nearly a decade,  *
Unfortunately,  the University of Rochester work was undertaken
prior to widespread recognition of the automobile emissions problem,
and,  as a consequence,  emissions characteristics of the Brodersen
engine were  not determined.   Another prechamber engine receiving
                                                                7 R
attention in the early 1960's is that conceived by R. M. Heintz.
The objectives  of this design were reduced HC emissions, increased

-------
                                  121
fuel economy and more flexible fuel requirements,
               Experiments with a prechamber engine design called
                                                                  79
"the torch-ignition engine" were reported in the U.S.S.R, by Nilov
                                  ori
and later by Kerimov and Mekhtier,    This designation refers to the
torch-like jet of hot combustion gases issuing from the precoinbustion
                                                81
chamber upon ignition.  In a recent publication.,   Varshaoski et _al.
have presented emissions data obtained with a torch-ignition engine,
These data show significant pollutant reductions relative to
conventional engines; however, their interpretation in terms of
requirements based on the U.S. emissions test procedure is not clear,
          (2)  Current developments -- A carbureted three-valve,
prechamber engine, the Honda CVCC system, has received considerable
                                                          82
recent attention as a potential low-emissions power plant.    This
system is illustrated in Figure 10-8.  Honda's current design
employs a conventional engine block and piston assembly.  Only the
cylinder head and fuel inlet system differ from current automotive
practice.  Each cylinder is equipped with a small precombustion
chamber communicating by means of an orifice with the main combustion
chamber situated above the piston,  A small inlet valve is located
in each prechamber.  Larger inlet and exhaust valves typical of
conventional automotive practice are located in the main combustion
chamber.  Proper proportioning of F/A mixture between prechamber
and main chamber is achieved by a combination of throttle control
and appropriate inlet valve timing,  A relatively slow and uniform
burning process giving rise to elevated combustion temperatures late
in the expansion stroke and during the exhaust process is achieved.
High temperatures in this part of the engine cycle are necessary
to promote complete oxidation of HC and CO.  It should be noted that
these elevated exhaust temperatures are necessarily obtained at the
expense of a fuel economy penalty.

-------
                             122
FIGURE 10.8  Honda CVCC Engine.
Source:  Reference 86

-------
                                  123
                To  reduce  HC  and  CO emissions  to required levels,  it
has  been  necessary for  Honda to  employ  specially designed inlet and
exhaust systems.   Supply  of  extremely rich  F/A mixtures  to the
precombustion  chambers  requires  extensive  inlet manifold heating to
provide adequate  fuel vaporization.  This  is  accomplished with a heat
exchange  system between inlet and  exhaust  streams.
                To  promote maximum  oxidation of HC and CO in the lean
mixture CVCC engine exhaust  gases, it has  been necessary to conserve
as much exhaust heat as possible and also  to  increase exhaust
manifold  residence time.   This has been done  by using a  relatively
large  exhaust  manifold  fitted with an internal heat shield or liner
to minimize heat  losses.   In addition}  the  exhaust  ports are
equipped  with  thin metallic  liners to minimize loss of heat from
exhaust gases  to  the cylinder heat casting.
                Engines  similar in  concept  to  the Honda CVCC system
are  under development by  other companies including  Toyota and Nissan
in Japan  and General Motors  and  Ford in the United  States.
               Honda presently markets  a CVCC-powered  vehicle  in
Japan  and  plans U.S. introduction  in 1975.  Other manufacturers,
including  General Motors  and Ford  in the U.S., hafe  stated  that
CVCC-type  engines  could be manufactured  for use  in  limited  numbers
of vehicles by  as early as 1977  or 1978.
      c.    Emissions gnd fjjel economy with CVCC-type  engines
           (1)  Recent emissions  test results — Results  of  emissions
tests with the Honda engine have been very promising.  The  emissions
levels shown in Table 10-3 are typical  and demonstrate that  the
Honda engine can meet statutory HC and  CO standards  and  can  approach
                           Q O
the statutory NO  standard.    Of particular importance,  durability
                X.
of this system appears  excellent as evidenced by the high mileage
emissions  levels reported  in Table 10-3.  A.ny deterioration  of

-------
                                   124
 emissions after 50,000 miles of engine operation was slight
 and apparently insignificant.
                             TABLE 10-3
                  Honda Compound Vortex-Controlled
                Combustion-Powered Vehicle  Emissions
                                                         Fuel Economy,
                                  Emissions3                  mpg
                             	g/mi	   1975     1972
                               HC       CO       NO      FTP      FTP
                                      	  x	     	
 Low Mileage Car3 No.  3652     0,18     2.12     0.89    22.1     21.0
 50,000-Mile Car   No.  2034     0.24     1.75     0,65    21.3     19-8
 1976 Standards                 0.41     3,4      2.0
 1977 Standards                 0.41     3.4      0.4
  Honda  Civic  vehicles,
 21975 CVS  XH  procedure with  2000-lb  inertia weight.
 3
  Average of five  tests,
 4
  Average of four  tests,
	I	____	.	             REF.  83
               Recently,  the EPA has  tested a  larger vehicle
                              84
 converted  to  the Honda system.    This vehicle, a  1973 Chevrolet
 Impala with a 300-CID V-8 engine, was equipped with cylinder  heads
 and an induction system built by Honda.  The vehicle met the  1976
 interim federal emissions standards though NO  levels were
                                             A!
 substantially higher than for the much lighter-weight Honda Civic
 vehicles.

-------
                                125
                Results of development tests conducted by General
                               g c

Motors are shown in Table 10-4.    These tests involved a 5,000 Ib


Chevrolet Impala with stratified-charge engine conversion.  EC and CO


emissions were below 1977 statutory limits, while NO  emissions
                                                    X

ranged from 1.5 to 2.0 g/mi.  Average CVS-CH fuel  economy was 11.2


miles per gallon.
10-4
Emissions and Fuel Economy for
Chevrolet Impala Stratified-
Charge Engine Conversion


Test
1
2
3
4
5
Average


Exhaust
Emissions }
g/mi
HC
0.20
0,26
0.20
0.29
0.18
0.23
CO
2.5
2,9
3.1
3,2
2.8
2.9
NO
X
1.7
1,5
1.9
1.6
1.9
1.7


Fuel
Economy,
rapg
10.8
11.7
11.4
10.9
11.1
11.2

1CVS-CH, 5,000-lb inertia weight.
REF. 85
            (2)  HC control has a significant impact on fuel economy --
In Figure  10-9, fuel economy data for several levels of HC emissions


from CVCC-type stratified-charge engines are plotted.  '   At the


1.0 g/mi HC level, stratified-charge engine fuel economy appears

-------
     28
     26
 a.
 _§


 O   24
u
O
O
UJ
_i
LJJ
D
Uu
     22
     20
     18 —
                               NO -1.2
1.5 liter
                           NO -0.9
                         2 liter
                                2750 Ib
                                     * HONDA CVCC-2000 Ib

                                     O DATSUN NVCC
                                                      2500 Ibs

                                                      NO -1.5
0,2             0,4              0.6

       HYDROCARBON EMISSIONS, CVS-CH
                                                                         0.8
                                                             1.0
FIGURE  10.9  Fuel Economy Versus  HC Emissions for  3-Valve Prechamber Engines.
Source:   References 86,  87

-------
                                   127
better than the average fuel economy for 1973-74 production vehicles
of equivalent weight.   Reduction of HC emissions below the 1,0 g/mi
level necessitates lowered compression ratios and/or retarded ignition
timing with a consequent loss of efficiency.   For the lightweight
(2,000-lb) vehicles, the 0.4 g/mi RC emissions standard can be met with
a fuel economy of 25 mpg, a level approximately equal to the average
                                                 7?
of 1973 production vehicles in this weight class. *~  For heavier cars,
the HG emissions versus fuel economy trade-off appears less favorable.
A fuel economy penalty of 107* relative to 1974 production vehicles in
the 2,750-lb weight class is required to meet the statutory 0.4 g/mi
HC level.
           (3)  Effect of HO  emissions control on fuel economy -- Data
                            X                                 "     86
showing the effect of NO  emissions control appear in Figure 10-10.
                        3C
These data are based on modifications of a Honda C,VCC-powered Civic
vehicle  (2,000-lb test weight) to meet increasingly stringent NO
standards ranging from 1,2 g/mi to as low as 0.3 g/mi.  For all tests,
HC and GO emissions are within the statutory 1977 standards.
                NO  control as shown in Figure 10-10 has been effected
                  x
by use of EGR. in combination with retarded ignition timing.  It is
clear that control of NO  emissions to levels below 1,0 to 1.5 g/mi
                        x
results in significant fuel economy penalties.  The penalty increases
uniformly as NO  emissions are reduced and appears to be 25% or more
               j\.
as the 0.4 g/mi NO  level is approached.
                It should be emphasized that the data of Figure 10-10
apply specifically to a 2,000-lb vehicle.   With increased vehicle
weight, NO  emissions control becomes more difficult and the fuel
          yi
economy penalty more severe.  The effect of vehicle weight on NO
emissions is apparent when comparing the data of Table 10-3 for 2,000-
lb vehicles with that of Table 10-4 for a 5,000-Ib vehicle.  While HC
and CO emissions for the two vehicles are roughtly comparable, there
is over a factor of two difference in average NO  emissions.

-------
    26
      r
 oi  24
 CL
 I
 o
 CO

 o
 O
 2
 o
 o
 LU

 _l
 UJ
 D
 LL
    22
20
    18
                                     128
                                                                 HC-0.23

                                                                 CO-2.2
                               O
                                                      o
                                                   HC-0.17

                                                   CO-2.3
                        /
                               O HC-0.33

                                  CO-3.0

                       O
                       HC^O,2
                       CO-2,7
                      0.2
                            0,4
0.6
0.8
1.0
1.2
                                NOV EMISSIONS, CVS-CH (g/mi)
                                   /\
FIGURE 10,10   Fuel Economy Versus NOX Emissions  for Honda CVCC  Powered

Vehicles.
Source:   Eeferen.ee 86

-------
                                 129
      d.  Fuel requirements -- To meet present and future U.S.
emissions-control standards, compression ratio and maximum ignition
advance are limited by HC emissions control rather than by the octane
quality of existing gasolines.  CVCC engines tuned to meet 1975
California emissions standards appear to be easily satisfied with
presently available 91 RON commercial unleaded gasolines.
          CVCC engines are lead-tolerant and have completed emissions
certification test programs using leaded gasolines.  However, with
the low octane requirement of the CVCC engine as noted above, the
economic benefits of lead antiknock compounds are not realized.
          It is possible that fuel volatility characteristics may be
of importance in relation to vaporization within the high-temperature,
fuel-rich regions of the prechamber cup, inlet port and prechamber
inlet manifold.  However, experimental data on this question do not
appear to be available at present.

10.4  Pi videcl--_Ch amber Staged Combustion.Engines (Large-Volume
      Prechamber Engines, Fuel-Injected Blind Prechamber Engines)
      a.  General — Dual-chamber engines of a type often called
"divided-chamber" or "large-volume prechamber" employ a two-stage
combustion process.  Here initial rich-mixture combustion and heat
release (first stage of combustion) are followed by rapid dilution of
combustion products with relatively low-temperature air (second
state of combustion).   The object of this engine design is to effect
the transition from overall rich combustion products to overall
lean products with sufficient speed that time is not available for
formation of significant quantities of NO.   During the second low-
temperature, lean stage of combustion, oxidation of HC and CO goes
to completion.
          An experimental divided-chamber engine design that has been

-------
                                  130
                                                              87,88
built and tested is represented schematically in Figure 10-11.
A dividing orifice (3) separates the primary combustion chamber  (1)
from the secondary combustion chamber (2), which includes  the
cylinder volume above the piston top.  A fuel injection (4) supplies
fuel to the primary chamber only.
          Injection timing is arranged such that fuel continuously
mixes with air entering the primary chamber during the compression
stroke.  At the end of compression, as the piston nears its top
center position, the primary chamber contains an ignitable F/A
mixture while the secondary chamber adjacent to the piston top
contains only air.  Following ignition of the primary chamber mixture
by a spark plug (6) located near the dividing orifice, high-
temperature, rich-mixture combustion products expand rapidly into
and mix with the relatively cool air contained in the secondary
chamber.  The resulting dilution of combustion products with attendant
temperature reduction rapidly suppresses formation of NO.  At the
same time, the presence of excess air in the secondary chamber tends
to promote complete oxidation of HC and CO,
      b.  Exhaust emissions and fuel economy — Results of limited
research conducted both by university and industrial laboratories
indicate that NO  reductions of as much as 80%-957» relative to
                x
conventional engines are possible with the divided-chamber staged
combustion process.  Typical experimentally determined NO  emissions
                                     89                  x
levels are presented in Figure 10-12.    Here NO  emissions for  two
                                                X
different divided-chamber configurations are compared with typical
emissions levels for conventional uncontrolled automobile engines.
The volume ratio,  g  appearing as a parameter in Figure 10-12,
represents the fraction of total combustion volume contained in
the primary chamber.   For  g  values approaching 0.5 or lower, NO
                                                                 X
emissions reach extremely low levels.  However, maximum power output
capability for a given engine size decreases with decreasing  6  values.

-------
                         131
                       Fuel Injector
FIGURE  10.11   Ford Divided Chamber.
Source:  References 87,

-------
                          132
    5000
 E  4000
 a
 a
o
ac
co
LU
a
x
o
I
X
    3000—
2000
    1000
               MBT Ignition Timing
               Wide Open Throttle
                      Conventional
                      Chamber
                     Fraction of Total Combustion
                     Volume in Primary Chamber
                             Divided Chamber, $ - 0.85
                              Divided Chamber, {} = 0.52
            0.5    0.6     0.7    0.8    0.9    1.0
                    OViRALL FUEL-AIR RATIO
                                              1.1
FIGURE 10,12  Comparison of Conventional and
Divided Combustion Chamber  NO  Emissions.
                                  x
Source:  Reference 90

-------
                                 133
Optimum primary chamber volume must ultimately represent a compromise
between low emissions levels and desired maximum power output,
          KG, and particularly CO, emissions from the divided-chamber
engine are substantially lower than conventional engine levels,
However, further detailed work with combustion-chamber geometries
and fuel-injection systems will be necessary to fully evaluate
the potential for reduction of these emissions.
          Recent tests by Ford Motor Company show that the large
volume prechamber engine may be capable of better HC emissions
control and fuel economy than their PROCO engine.  This is shown
by the laboratory engine test comparison of Table 10- 5
                                                      .83

Engine
PROCO
Divided Chamber
PROCO
Divided Chamber
TABLE 10-5
Single-Cylinder Low Emissions
Engine Tests

NOX
Reduction
Method
EGR
None
EGR
None

Emissions,
g/1. hp-hr
NO
X
1.0
1.0
0.5
0,5
HC
3.0
0.4
4.0
0.75
CO
13.0
2.5
14.0
3.3
i
Fuel
EC o no ray s
lb/1, hp-hr
0.377
0.378
0,383
0.377 REF, 83
          Fuel-injection-spray characteristics are critical to the
control of HC emissions from this type of engine, and Ford's success
in this regard is probably due in part to use of the already highly-
developed PROCO gasoline injection system.  Figure 10-13 is a cutaway
view of Ford's adaptation of a 400-CID V-8 engine to the divided-
 t,  t,          90
chamber system.

-------
                401 CIO
                                                                                           UJ
FIGUHS  10.13
Source:  Reference 90

-------
                                   135
           Volkswagen (VW) has recently published results of a
                                                                  91
 program aimed at development of a large-volume prechamber engine.

 In the VW adaptation, the primary chamber which comprises about 307,
 of the total clearance volume is fueled by a direct,  time injection
 system, and auxiliary fuel for high-power output conditions is

 supplied to the cylinder region by a carburetor.
           Table 10- 6 presents emissions data for both air-cooled
                                                          92
 and water-cooled versions of VW's divided-chamber engine. "  Emissions
 levels, while quite  low, do not meet the ultimate 1978 statutory U.S.
 standards.
                             TABLE 10-6
                      Volkswagen Large-Volume
                    Prechamber Engine  Emissions
     Engine
                    Exhaust
                   Emissions,
                      g/nii
HC
CO
NO,
Engine Specifications
1.6 Liter
Air-Cooled
2.0-Liter
Water-Cooled
 CVS -CH
2.0
5.0
0.9
1.0
4,0
1.0
8,4:1 compression ratio, pre-
chamber        2870 of total
clearance volumes conventional
exhaust manifold, direct pre-
chamber fuel injection

9:1 compression ratio, prechamber
volume 281 of total clearance
volume, simple exhaust manifold
reactor? direct prechamber fuel
injection
                                                                 REF. 92

-------
                                   136
      c.   Problem Areas
          A number of major problems inherent in the large volume
prechamber engine remain to be solved.   These problems include the
following:
          Fuel injection spray characteristics are critically important
          to achieving acceptable HC emissions.   The feasibility of
          producing a satisfactory injection system has not been
          es tablished.
          Combustion noise  due to high  turbulence levels and, hence,
          high rates  of  heat release and pressure rise in the
          prechamber,  can be excessive.   It  has  been shown that the
          noise level  can. be modified through careful chamber design
          and combustion event timing.
          If the  engine  is  operated  with prechamber fuel injection as
          the sole fuel  source, maximum  engine pox^er output is
          limited.   This might be overcome by auxiliary carburetion
          of the  air  inlet  for maximum power demand or possibly by
          turbocharging.  Either  approach adds to system complexity.
         The engine  is  characterized by low exhaust temperatures
          typical  of most lean mixture engines.

-------
                          11.  DIESEL ENGINES
11.1  Introduction
      Many  techniques have been  sought  for  reducing  the harmful
emissions from passenger cars  in an effort  to clean  the air.  Exhaust-
emissions standards have been  set by the  federal government and  the.
state of California for three  species;  hydrocarbon  (HC), carbon
monoxide (CO) and nitrogen oxides (NO ).  It is expected that other
                                     5C
species which are equally or even more  harmful than  these will be
controlled  in the future,
      The regulated and nonregulated emissions from  diesel-powered
cars are studied in this Section,  The  fuel economy  and initial  and
maintenance costs of the diesel  are compared with the gasoline engine.
Finally, the intrinsic problem areas associated with the auto-ignition
process in  the diesel engine are examined.
      The approach taken in this Section  is to compare the characteristics
of the diesel-powered cars with  those of  cars powered by regular
gasoline engines, stratified-charge engines, Wankel, or gas turbine
engines.

11.2  Regulated Emissions
                               93
      a.  General -- Table 11.1  and Figure  11.1 give a summary of tests
carried out by EPA-Ann Arbor,  and recent  results obtained from the
manufacturers.   The Mercedes 220V and 240D  and Datsun-Nissan 220C
have an inertia weight of 3,500  Ib, and the Peugeot 504D and Opel
Rekord 2100D have an inertia weight (I.W.)of 3,000 Ib.   All of these
engines have four cylinders. The hydrocarbon emission from the
Peugeot 504D was 3.1 g/mi which  is very high compared to all other
                                                          94
diesel-powered cars.   Recent results by Southwest Research    showed
that the Peugeot 504D produced 2,0 g/mi HC,   Peugeot Inc. reported
at a meeting of foreign manufacturers held by the Committee on Motor
Vehicles Emissions May 21-23,   1974, that with modifications, their
                                   137

-------
                                                TABLE 11.1
Vehicle

Mercedes 220D
Mercedes 220D
   (modified)

Mercedes 240D

Peugeot 504D
Peugeot 504D
   (modified)
Datsun-Nissan 220C
   (as received)
Datsun-Nissan 220C
   (after 4,000 miles)

Opel Rekord 2100D

Pick-up Truck
    Retrofit (Nissan
     Diesel)
                                      Mass Emissions and Fuel Economy
                                            From Diesel Engines
                                         (1975 Federal Test Procedure)




Inertia
No. of Tests Weight
5
5
3
5
3
3
3
3
,500
,500
,500
,000
Ib
Ib
Ib
Ib



Transmission
4
4
4
4
speed
speed
speed
speed
auto
auto
auto
manual

HC
(B/mi)
0.34
0.28
0.18
3.11

CO
(B/mi)
1.42
L.oe
1.0
3.42


KOX
(B/mi)
1.
1,
1.
1.
43
48
5
07
Fuel
Economy
(mpg)
23.6
24,6
23. 61
25.2
(Manufac turer's
     Data)      3,000 Ib

     2         3,500 Ib
4 speed manual

4 speed manual
0.40-0,60 1,1-1.6  1.3-L.5

  0.38     1.69     1.72
             24.0
2
4
3
3
,500
,000
Ib
Ib
4
3
speed
speed
manual
auto
0.23
0.40
1.34
1.16
1,
1.
36
34
28,1
23.8
                                                                                                              Ul
                                                                                                              00
               4,500 Ib   4 speed manual
                    1.70
           3.81
1.71
21.4
 The fuel economy in this case is based on one measurement only.
                                                                                        REF 93

-------
                            139

3
1
X
O
z
1

20
_ 16
E
3 12
O
u
8
4
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FIGURE 1101  Emissions from Diesel Powered Cars (1975 FTP)
Source;  Reference 94

-------
                                   140
ear produces 0,6 g/tui HC»
          Figure 11,1 shows that all of  these diesel-powered  cars,
except the Peugeot 504D? can meet the 1975-76 Federal,  1975-76
California, and 1977 Nationwide Standards for HC, CO  and NO  .  Also,
                                                           J^
all these cars, except the Peugeot 504D, can meet the 1978 Nationwide
Standards for HC and CO,  The problem with these diesel-powered  cars
is in meeting the NO  emissions standard of 0,40 g/tai in 1978.
                    x
          Some HO  controls have been applied to the  diesel engine
                 x
and were found to affect the other emissions.
          The control of NO  emissions in diesel engines should  be made
                           x
during the combustion process.  Whereas gasoline engines can  employ a
reduction catalyst  *   to control NO , such a technology is  not
                                     x
effective in diesel engines because of the low level  of CO, and  the
presence of a relatively high concentration of oxygen in the  exhaust,
even under full-load conditions,
          Reduction in NO  formation during the combustion process is
achieved by reducing either the maximum temperature reached,  the oxygen
                                     97
concentration, or the residence time.     This can be achieved by any
of the following methods or a combination of them.
      b.   Exhaust gas_ recirculation -- EGR (exhaust gas recirculation)
is an effective method for the  reduction of NO  emissions in  diesel
                                              x
as well as in many other types  of combustion engines.   It is  believed
that its main effect is to reduce the maximum temperatures by
increasing the heat capacity of the charge,
                                           98
          Data reported by Daimler-Benz AG    are given in Figure 11,2
for a speed of 2,400 rpm and two loads.  Increasing EGR reduces  NO
                                                                  nfC
with little effect on HC and CO up to EGR values of 20%, where NO
                                                        '         x
is reduced by about 20% at the  low load and 30% at the higher load.
Increasing EGR above 20% results in an increase in HC  and CO  emissions,
The smoke starts to increase at 40% EGR at the light  load and 20% EGR

-------
                                     141
                  n = 2,400 mirf
SZ-BOSCH
3
1
p = 1.8 kp/cm2
—
                                                       n -- 2,400min '

                                                       pc = 3.6 kp/crn2
     0.2
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                                                 120 i~
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 0
    200 r—
  E
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  O  100 —
               10
                     20       30


                    EGR  {%)
                                       40
         10      20


             EGR (%)
30
FIGURE  11.2  Effect  of EGR  on the Emissions from  a  Mercedes

Diesel  Engine.
Source:   Reference  98

-------
                                    142
at the higher load.  The Daimler-Benz results are  for  steady-state
conditions.
          The effects of EGR on the emissions under  the  1975  Federal
                                                                99
Test Procedure (FTP) are reported for an Opel Rekord diesel car,
and are shown in Figure 11.3.  The increase in EGR increases  both
HC and CO emissions above the 1977 standards, while NO  is still above
                                                       5C
the 1978 standards of 0.4 g/mi.  From this figure, it  appears  that
EGR is effective in reducing NO  to about 1.0 g/mis while the  HC and
                               5t
CO emissions are below the 1977 and 1978 standards of  0.41 and 3.4
g/tni, respectively.
          Daimler-Benz reported that EGR does not  affect power or
cause fuel penalty at part-load conditions.  The effect of EGR on
durability is still being investigated.
          EGR can be achieved by recycling the exhaust gases  from  the
exhaust to the inlet manifolds.  Limited EGR is obtained by changing
the valve overlap.  The optimum percentage of EGR  required to  reduce
NO  varies with load.  Efforts are being made to optimize the  EGR  at
different loads to minimize the penalty in fuel economy and the
emissions of HC,  CO and smoke.
      c.  I nj e c_tion timing -- Retarding the injection  is an effective
way to reduce the NO  emissions because of its effect  on maximum
temperature and residence time.  Retarding the timing  also affects
the HC and CO emissions.  Results reported by Opel on  the Opel Rekord
diesel car, using the 1975 FTP are shown in Figure 11.4.  By retarding
the static injection from 6  BTDC (before top dead center) to  1.5
BTDC, NO  emissions dropped by 30% (from 2.47 g/mi to  1.73 g/mi),
        A
while the HC and CO emissions increased by 44% and 337=., respectively.
          Results obtained from Perkins,    given  in Table 11.2, show
the effect of retarding the injection timing by 4  with respect to
the standard timing of 21  before top dead center.

-------
                                   143
                                                                  1.9
 o


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 o
 o

              36
28
                        34        32        30



                           OVERALL AIR/FUEL RATIO



FIGURE 11.3  Effect of EGR on Opel  Rekord  Diesel  Car (1975 FTP).
26
                                                                 0,3
Source:  Reference 99

-------
                             144
   0.6
   1.7
FIGURE  11.4
              12345



                   STATIC INJECTION TIMING C'BTC)
Source:   Reference 99

-------
                                   145

                              TABLE  11.2
    Effect of Injection Timing on Emissions  from  Perkins  154  Engine
                    in Ford Zephyr Car  (CVS  Cycle)
      Standing Timing              Retarded  Timing         %  Change
         21° BTCD                       17° BTDC
           g/rni                          g/mi
HC          0.46                         0.66               +  43%
CO          2,79                         3.78               +  35%
NQx         2.33                         1,73               -  267,
                                                                REF.  100

          Perkins reports that  the change  in fuel economy caused  by
this injection retard is within +670  (which  is their production
tolerance), and that there has been  no problem in meeting the smoke
levels regulated by the European governments.
          Retarding the injection is effective in reducing NO , but
                                                             ,A
causes an increase in HC and CO.  The 1978  emissions standards cannot
be achieved by diesel-powered cars by using either injection retard
or a combination of injection retard and EGR.
      d.  Other controls -- Other techniques used to reduce the NO
emissions are control of the air/fuel ratio at light loads,    use of
                97
water injection,    use of fuel additives  (Ref.  98  p. 749), use  of
low compression ratios together with supercharging, and modifications
in the fuel-injection system and combustion-chamber design.
      e-  Summary — In summary, the automotive diesel engine
manufacturers are uncertain that they can meet the 0,40 g/mi standard
for NO  in the future, even in an experimental engine.  They feel
      x
that the diesel engine can meet a level of NO  = l.i>-2.0 g/ni with
                                             JV
little changes in the design of current production engines, without
any penalty in fuel economy.   Ricardo and Co. Engineers, in a recent

-------
                                   146
             102
report to EPA,   indicated that a conventional, naturally aspirated
swirl-chamber diesel engine, in a 3,500 Ib vehicle, should be able  to
achieve HC = 0,41 g/mi, CO = 3.4 g/ml and NO  =1,5 g/mi.  Some EGR
may be necessary to ensure a sufficient margin for production tolerances,
          It is anticipated that levels of NO  equal to 1.0 g/mi, or
even as low as 0.6 g/mi, might be reached in the future if sufficient
research is made to optimize all the NO  control techniques,
                                       .X

11.3  Monr egu.1 a ted_Emi s_s ions
      The nonregulated emissions studies in this Section are:
particulates, benzo (a) pyrine, sulfur dioxide, sulfuric acid,
aldehydes and ammonia.  Many of these nonregulated pollutants are
as harmful or even more harmful than the three regulated species.  It
is expected that some of these undesirable species will be regulated
in the future,
      a»  Farticulates -- Particulates from diesel engines appear as
blue and white smoke under cold-running conditions and low loads, and
as black smoke near full-load operation.  The blue and white smoke
contains unburned and partially oxidized fuel, and the black smoke
is mainly carbon.
                     93
          Figure 11.5   shows the airborne particulate emissions in
grams per mile on the 1975 FTP from three diesel powered cars, two
American 1975 gasoline-powered cars, and a PROCO-Capri car.  The two
gasoline cars are equipped with catalytic converters.  In one of the
gasoline cars, the aged catalyst increased the particulate emissions
by 267%.  The PROCO-Capri car produced more particulates than the
gasoline cars.  The diesels produced the highest concentration of
particulate emissions.
          The proposed level of 0.1 g/mi over the constant-volume-
sampling cycle during the federal testing procedure is difficult to
achieve by the diesel engine,  A proposed method to reduce particulate

-------
                                 L47
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FIGURE LI,5  Airborne Particulates Emitted from Diesel and Gasoline
Powered Cars,
Source:  Reference 93

-------
                                    148
                                           102
emissions  is a soot filter  (non-catalytic)    which  would hold soot
particles  emitted  at part loads  and  burn  them at  high  loads  when the
exhaust  temperatures are high  enough to cause their  oxidation.
       b,   Benzo(a)pyrine -- Benzo(a)pyrine  (BAP)  is  an undesirable
carcinogenic species emitted from combustion engines.   Among the
factors which affect its concentration in  the engine exhaust is the
concentration of aromatics  in  the fuel.  Without  adding tetraethyllead
to  the gasoline, the concentration of the  aromatic compounds in the
fuel has to be increased to arrive at a fuel with a  reasonable octane
number and combustion characteristics.  This might result in an
increase in BAP emissions in the gasoline  engine  exhaust  in  the future.
          A comparison between the BAP emissions  in  three diesel-cars
and for gasoline cars is shown in Figure 11.6 for 1975 FTP cold start,
                                                        103
and in Figure 11.7 for 60-tnph, steady-state conditions,
           BAP emissions in  the diesel exhaust are fairly  low under
C'-irtibined cold starting and SO-mph, steady running if compared with
the gasoline engine.  The diesel-engine BAP emissions  are of the same
order of magnitude as the stratified-charge engines.
          The above observations are for a limited number of vehicles;
additional data covering a larger number of vehicles are  needed to
i-tudy the BAP emissions from different types of automotive engines,
      c.   Sulfur compounds — The concentration of the  sulfur compounds
in Che exhaust is directly related to the sulfur  content  of  the fuel,
iHffi Federal Register specifies the sulfur content to be 0.05%-Q.2Q%
for type 1-D and 0.2%-0.5% for type  2-D diesel fuel  and less  than  0.1%
£or gasoline.   Figure 11.8 shows the sulfur dioxide  and sulfuric acid
n?ss emissions in grams per mile for two gasoline-and  one  diesel-
                                                           93
powered car,  and the percent of  sulfur converted  to H  SO,,       The
                                                     2  4
:  :i;s  are at  60 mph, steady-state running conditions.  The H.SQ, mass
•missions are  almost the same for the diesel and  gasoline  engines,  in

-------
                               149
    360 r-
    320-
    280 —
                           Diesel:
                           Gasoline:
1. Mercedes
2. Opel
3. Peugeot
1. 72 Pontiac
  +• Catalyst + Air
2- Ford
  (.41.3.4,3.1)
3. 11 Ford
  •*• Fresh Catalyst + Air
1. 72 Ford
  -t- Aged Catalyst + Air

E 240
Q.
Q.
ST
S 200
LU
z
LU

-------
                               150
   360



   320



   280


"§
-  240
CD

LU
111
£E
    200
5  160
N
    120
     80
     40
                                  Diesel:
                                  Gasoline;
                                 Stratified
                                 Charge:
                               £L
                                              Mercedes
                                              Opel
3.  Peugeot
1.  72 Pontiac
   + Catalyst -t- Air
2.  Ford
   1.41,3.4,3,1}
3.  72 Ford
   +• Fresh Catslyst +• Air
4.  72 Ford
   + Aged Catalyst +• Air
1.  Cricket TCCS
2.  74 Ford Capri Proco
                                                  T3
                                                  OJ

                                                  | |

                                                  in O
FIGURE 11.7   Benzo(a)Pyrene  ImiaBlons  from  Different
Automotive Engines  at 60 mph Steady Running Conditions.
Source:   Reference  103

-------
                      151
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n n
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S £ < "
Qeo ~*~ "w" ?
*^ o w> •*-
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^ .1 ? S u c
° i ^ | s -" =
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FIGURE 11,8  Sulfur Compounds Emissions from
Different Cars.
Source:   Reference 93

-------
                                    152
spite of  the fact that the sulfur content of the diesel  fuel  used  in
these tests was 10 times that of gasoline.  The SO  emissions  in
diesel exhaust are about three or four times that of  the gasoline
exhaust.
          The control of SO  and H SO, emissions in the  diesel  exhaust
can be achieved in the refinery by reducing the sulfur content  of  the
fuel.  This may cause an increase in the fuel cost,
      d.  Aldehydes -- The aldehydes are partially oxidized hydrocarbons
and are mainly formaldehyde.  Other aldehydes emitted from combustion
systems are higher aliphatic aldehydes, aromatic aldehydes, and
aliphatic ketones.
          All of the results in this Section are reported as  formalde-
          104
hyde HCHO,     The aldehyde emissions are given in Table 11.3      for
tvo cars  equipped with diesel engines, two with models of Wankel
engines,  four vith gasoline engines, two with stratified-charge
                                                 103
engines,  and one with a gas turbine.  The results     are for  the
emissions during 43 minutes of the Modified Federal Cycle Cold Start
(MFCCS) and one-hour, steady-state, 60-mph hot start.  The results
for the Honda and Opel Diesel (reports 1 and 2 in Table  11.3) are  for
the original Federal Cycle Cold Start.  The MFCCS aldehydes are
plotted for the Peugeot and other cars in Figure 11.9.   It is noticed
that the  cars powered with engines using a heterogeneous mixture
(except for Ford PROCO) produce higher aldehyde emissions.  The Ford
PROCO car is equipped with a catalytic converter.
          The aldehyde emissions under the steady-state, 60-mph test,
are shown in Figure 11.10.
          The contribution of the aldehydes to air pollution  should
not be overlooked since their specific reactivity is higher than many
unburned hydrocarbons     in photochemical smog formation.  Also, their
effect on health and plant damage is worse than many unburned
,   ,     ,     106
hydrocarbons,

-------
                               153



                            TABLE 11.3




   Aldehydes and Ammonia Emissions from Different  Types  of Cars
HCHO
PPM
Report
No.
1*

2*
3

4



5
6

7

8

9

10


11

12



13

14

15

16

L7

Vehicle
Honda Prototype
Civic CVCC engine
1973 Opel Diesel
Peugeot, 4 Sp. trans.,
Diesel Fuel #2
RX2 Mazda D1527
(Thermal Reactor and
a reactor by-pass) air
pump and EGR
EPA Williams Gas Turbine
Yellow Mazda RX3
(Equipped as in Rep. #4)
72 EPA Ford, durability
Catalyst, Veh. 24A51
72 EPA Ford, SLAVE
Catalyst, Veh. 24A51
Mazda D1527 RX2 Silver
(Equipped as in Rep. #4)
Pontiac 1972 GM 2477
with 1975 hardware with
30,768 miles
Yellow Mazda RX3
(Equipped as in Rep. #4)
EPA Ford, 1973, A 342-25
(designed for HC = 0.41,
CO = 3.4 and NO =3.1)
X
Mazda RX3
(Equipped as in Rep. #4)
1974 Ford Capri EPA 019L
(PROCO)
EPA CRICKET TCCS #8
(with catalytic converter)
EPA CRICKET TCCS #8
(with catalytic converter)
Mazda RX3 7,226.0 miles

MFCCS

1.7
17.5

602.5

924.6


349.1

381.6

14.67

74.04

862.9

21.41


345.56

71.67



592.9

38.86

524.6

805.2
665.7
60 mph
S.S.

64.5
18.5

253.9

2,341.6


80.53
(50 mph)
1,541.3

3.1

26.29

1,385.1

23.3


1,479.8

149.83



1,564.1

31.46

181.9

204.1

NH3
PPM

MFCCS

3.5
19.4

11.1

8.8


15.14

9.32

3.37

2.52

5.81

20.7


10.9

25.31



14.03

6.53

1.72

1.32
5.74
60 mph
S.S.

9
38.9

7.28

32.9


28.20

89.37

0.88

0.75

32.5

17.35


36

7.28



36.5

13.67

1.29

.57

'^Reports  1 and  2  were on  the  original  federal  cycle cold  start.
                                                       REF 103

-------
                     154
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   800

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   200
TOO
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                       155
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FIGURE 11.10

Conditions.
HCHO for 60 mph  Steady  Running
Source:  Reference  103

-------
                                    156
      e.  Ammonia emissions  — The NH   emissions  from the dieseL and
                                        L03
other engines  are shown  in Table  11,3.       It  is  noticed that NH
is emitted  from all  the  combustion engines,  A  conclusion for the NH
characteristics of each  engine is difficult  to  make  at this  stage,
because of  the limited amount of  experimental data,

11.4  Fuel  Economy
      The better fuel economy of  the diesel  engine over the  gasoline
engine is the result of  its  higher compression  ratios,  higher air/fuel
ratios, and the absence  of the throttle valve for  load control in the
diesel.  Accordingly, the superior fuel economy of the diesel is at
part loads.
      The following figures  show comparative economy  results  for diesel-
and gasoline-powered cars, in many application.  Figure  11.11 shows
the results submitted by Daimler-Benz (Ref.98 p. 769)  for  the miles
per gallon  of  the MB220D diesel and the 1975 MB230 gasoline  engine
under steady-state conditions and at speeds up  to  75  mph.  Both cars
have an I.W. = 3,500 Ibs,  The savings  in fuel  consumption in the
diesel car varies from 53% at 30 mph to 32% at  70  mph.   Under the CVS
test, the MB220 diesel averages 23.6 mpg as compared  to  13.9-17.2 mpg
for the 1975 gasoline engine; i.e., an  average  saving  of  27%  to 4-1%
in fuel consumption.   Recent results obtained from EPA Ann Arbor
show that the 1975 MB240D diesel car averages 23 mpg, which makes it
as economical as the MB220D.
      It should be noted that part of the fuel saving  in  the  above
comparison is caused by the  lower horsepower of the diesel engine as
                                                       99
compared to the gasoline engine.   A comparison by  Opel,    based on
engines of equal power output fitted in the same car,  is given in
Table 11.4.

-------
      60
      50
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   .?  20
      10
                                         157
               Model: MB 220D Diesel
                     Model: MB 220
                     Gasoline, Europe
Model: MS 220 Gasoline
Model Year 1972
                               Model: MB 230 Gasoline
                               Model Year 1975
                       _L
     J_
               10      20      30      40      50
                                      SPEED (mph)
                            60
70
80      90
FIGURE 11.11   Comparison  of Fuel Economy at  Road Load for  Mercedes Diesel
and  Gasoline  Cars,
Source:   Reference  98

-------
                                    158

                              TABLE 11.4

           Comparison Between Opel DieseJ^and Gasoline Cars

                              Diesel Car             Gasoline Car

Car Weight, Its                  3,070                    2,750
Engine Displacement, CC          2^10
Miles Per Gallon
    (mixed-duty cycle)             34                      27
Saving                             21%                          R£F>

A similar comparison based on equal power is reported by Peugeot
on their 504 diesel and 404 gasoline engines.  Here the average
saving in fuel consumption is 26%.
                  109
      A comparison    between two foreign diesel cars and  an American
car, all having the same weight (3,000 Ib), is shown in Figure 11,12
for steady-state operation and in Figure 11,13 for city, suburban, and
average-driving conditions.  Here the average saving in fuel consumption
is 367, for the two diesel-powered cars.  It should be noted that a part
of this saving is caused by the use of manual transmissions in the
diesel cars as compared to an automatic transmission in the gasoline
car.
      The saving in fuel consumption in taxi application in two
                                       110
European cities is shown in Table 11.5.

-------
                                      159
      S
      o
      z
      o
      o
      HI
         50
         45
         40
         35
         30
         25
         20
         15
           20
                   73 Peugeot

                   4 Speed,M/T
                   73 Opel Rekocd

                   4 Speed. M/T
74 Mustang

3 Speed, A/T
  30
40          50


  SPEED (mph)
                                                         60
                                                                     70
FIGURE 11,12   Comparison of mpg for Different Cars Under  Steady State

Conditions.
Source;   Reference 109

-------
                        160
                                               City
    30
    20
     10
                                               n
 en
 a
 ,§  30
8  20
in
    10
                                           Suburban
    30
    20
    10
                                             Average
                   so
                   Q.
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                  53.

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FIGURE  11.13  Comparison of mpg for Different Cars

Under City, Suburban and Average Driving  Conditions,
Source:   Reference  109

-------
                                   161
                              TABLE 11.5

                 Fuel Economy in Taxi Application

                                Miles per gallon
London Taxi
Paris Taxi
Diesel
30.6
31.4
Gasoline
15.9
21.7
Saving
48%
317, _ „
                                                                REF.  110
Similar savings in fuel consumption have been reported by replacing
the gasoline engine with a diesel engine in U.S. Post Office one-half,
one-and five-ton vehicles    and in vans equipped with Perkins
A-        •    10°
diesel engines.
      Part of the higher miles per gallon for the diesel-powered
car is caused by the higher energy content of one gallon of diesel
fuel as compared to the same volume of gasoline, as shown in Table 11.6
(Ref.98 , p. 850).
                              TABLE 11.6

             Comparison Between Diesel and Gasoline Fuels
                         Average mass             Average BTU
      Fuel               j>er gallon               per gallon
      Diesel                  7.1                  137,750
      Gasoline                6.0                  123,500

                                                        REF. 98

The increase in the energy content of one gallon of diesel fuel is
127, above that of gasoline.

-------
                                    162
      From a total energy point of view, the energy expenditure  in
producing the fuel at the refinery should be taken into consideration,
Diesel engines can use a wide range of distillates which are produced
at a lower cost than gasoline.
      In summary, the average saving in fuel consumption by using the
diesel engine instead of the gasoline engine in passenger cars varies
between 257= to 50%.

11.5  Initial and Maintenance Costs
      Diesel engines initially cost about 50% more than gasoline
engines.  Half of this difference is attributed to the high cost of
                          102
the fuel-injection system,    and is partially caused by its limited
                112
mass production.     For a diesel engine to have the same power as a
gasoline engine,  it  should have a larger displacement volume, since
the air utilization is less.  Also, it should have heavier parts to
stand the much higher gas pressures produced in the cylinder as a
result of the higher compression ratio used.  These, too, increase
production costs  of  the engine.  The heavier starting motors and
batteries required to overcome the high  compression, pressures and to
the production cost  of the diesel-powered cars.
      However, the maintenance cost for the diesel engine is lower
than that for the gasoline engine.  The injection system does not
require the frequent maintenance and replacement of parts experienced
with the ignition system and carburetor of the gasoline engine,
although there is a  slightly higher cost for each service.  On the
other hand, routine  maintenance (oil and filter change) is more
frequent for the  diesel engine,
      Daimler-Benz reported the initial and maintenance costs for
                                       113
their MB 1975 gasoline and diesel cars.      These costs are given in
Table 11.7.  The  maintenance cost includes general maintenance (spark

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                               163
                           TABLE 11.7

           Initial and Maintenance Costs and Performance
                      of Mercedes 1975 Cars *
Diesel Gasoline
240D 2.3L

Vehicle Weight, Ib
Horsepower
California
Model
3,500 3,200
65 95
Federal
Model
3,200
95
Weight-Power Ratio
     Ib/HP

Fuel Economy
     mpg

Acceleration time, sec
     60 mpg

Initial Cost

Maintenance Cost for
     100,000 miles

Initial Price
     (1974 Model)

Total Cost for
     100,000 miles
     (assuming 1974
      Model Prices)
   6,8
 21-22
  24.6
$1,153


$8,715


$9,868
    2.6
   16.2
   13.7
 $2,590
 $8 420
$11,010
    2.6
   15.5
   13.7
 $2,590
 $8,420
$11,010
-'The initial cost for the Mercedes 1975 cars had not been
 announced by the company at the time of writing this report.
 The initial prices for the 1974 models are used for comparison.
                                                       REF  113

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                                    164
 plugs,  tuning, oil changes,  etc,)  and  two  catalyst  changes  for the
 gasoline  car.  The larger  cost differential  between the two cars in
 1975  is the high cost  for  the catalyst  change which was quoted at $600
 for this  six-cylinder  and  $800 for  the  eight-cylinder  gasoline engine.
 The 1974  maintenance costs are $1,132 for  the diesel and $1,062 for
 the gasoline engine,
      At  23 mpg for the 1975 diesel car and  16 mpg  for the  1975
 gasoline  car, and at 45c/gal for the diesel  fuel  and 55c/gal  for
 gasoline,  the fuel cost for  100,000 miles  would be  $1,957 and $3,438
 for the diesel and gasoline  cars,  respectively.   For the sake of
 comparison, considering 1974 model prices, Che estimated total initial
 maintenance and fuel costs are $11,825  for the diesel  and $14,448 for
 the gasoline car.  This means a saving  of  18% to  the owner  of the
 diesel-powered car.
      The  superior economy of the  diesel-powered  car over the gasoline-
 powered car is manifested in applications  involving part-load operations
 For example, taxicab fleet owners  in London  and other  cities  in Europe
 had to shift from the  gasoline to  the diesel engines to  make  a profit
 while keeping the fares within the limits  imposed by the local
 authorities,
      Diesel engines proved to be economical in taxicab  fleet
 operations even in countries x^here the  price of the diesel  fuel  is
 equal to or slightly higher than gasoline  fuel, such as  in  Great
 Britain,   In other countries where diesel  fuel is less expensive than
 gasoline,   the savings  increase proportionally.
      The present higher initial cost of the diesel-powered car  over
 the gasoline car is expected to diminish in  the 1975 model  cars  and
 those that follow.   For 1975 California cars and  1977  nationwide cars,
 the gasoline-powered cars should be equipped with catalytic converters
 and feedback systems.   Some of the gasoline engines will  be equipped
with fuel-injection equipment.   All these  add-on devices  will increase

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                                    165
the initial and maintenance  costs  of  the  gasoline-powered  cars  and make
the diesel-powered car more  economical.

11.6  Driveability -- The driveability of two Mercedes  diesel
automatic  transmission (A/T) vehicles  (1969  and  1974 models), a  1973
manual transmission  (M/T) Opel Rekord  and a  1973 M/T Peugeot were
compared to the driveability of  a  1973 Pinto and a Honda A/T CVCC
        109
vehicle.    The results  are  shown  in Figure  11.14,  The A/T diesels
were better than  the one A/1 gasoline  engine in  the following three
types of evaluation:  minimum driving  ratings, drive ratings average,
and the idel quality rating.  The  M/T  diesels were better  than  the
Honda CVCC M/T in two categories.   However,  the  Honda CVCG M/T was
better in  idle quality.  Daimler-Benz  reported that the driveability
of their diesel-powered  vehicle  is  the same  as their gasoline-powered
vehicle,

11.7  Intrinsic Problem_Areas
      a-  S^art^ing -- Automotive diesel engines  which can meet the
emissions standards have a prechamber  (Mercedes) or swirl-type
(Peugeot and Opel) combustion chamber.  These types of  combustion
chambers need a starting aid in  the form  of  a glow plug.  Because
the glow plug should reach a high  temperature before cranking the
engine, some delay in starting is  experienced.   At present, research
is being done on  a high-intensity  glow plug  to reduce starting delay,,
      b.   Noise -- The diesel engine is inherently noisier than  the
gasoline engine,  particularly after cold  start and during idling.  This
will be discussed under  the noise  emission classifications of exterior
and interior noise.
          Figure  11.15 shows a comparison made by the Ford Motor
Company between the exterior noise levels of three diesel-powered cars

-------
                           166
o
      7 [-
>w
cc o
°?   6h-
N
z
5     5 h
(3 I-
fy rr
LU

<    5
D
O
LU
                                            n
Q
O
111
•p
e
m
                                  Q
                                  S
                                  in
                        a;
                        EC
                        "S
                        CL
                        cn
                              en
                              IN
                              O
                              ^J
                              C
                              b.
                                                      O
                                                      o
o
10
•
FIGURE 11.14   Comparative Drivability of Diesel Powered
and Other Cars.
Source:  Reference 109

-------
w
o
pa
fD
l-l
(D
3
O
(D
O
VD
                                                   EXTERIOR NOISE LEVEL, dB{A)
to
H
H'
O
H
        O
        H-
n>
i->
03

IT)

O
g

a
H-
Hn
Hi
(D
        ft
        h
        in
                                                                                    CO
                                                                                    o
                                                                                                     00
                                                                                                     en
              6B Mercedes 220 D
              A/T
              & 73 Opel Rekord 2700 D
              M/T
              73 Peugeot 504 D
              M/T
              74 Maverick, 260 CIO
              M/T
              74 Pinto, 2.3L
              w/Sport Accent, M/T
              74 Torino 351-2V-W
              A/T High Series
                                              I    I
                                                                   1    1
                                                                            3 O
                                                                            • 13
                                                                            -* O

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                                    168
                                          109
 and  three American gasoline-powered cars.     This  comparison  is
 according to  the SAE Standard J 986a test procedures.-  This test
 calls  for a wide-open throttle acceleration from 30 mph to maximum
 engine revolutions-per-minute over a distance of 100  ft, with  a
 microphone stationed 40-50 ft away.  The results show that the three
 diesel engines have lower sound levels than the 1974  Torino and have
 the  same sound level as the 1974 Pinto.  Also, these  engines meet
 the  present California standards, and  those proposed  for 1975.  The
 1973 Peugeot  meets the proposed 1978 California standards.  The 1969
 Mercedes and  the 1973 Opel are 0.5 dB above the proposed 1978  California
 standards,
          Recent comparative noise results reported by Southwest
                  94
 Research Institute   are shown in Figure 11.16 and Table 11,8  for
 cars of different makes.   Figure 11,16 indicates that some diesel-
 powered cars  produced less exterior noise than the  gasoline-powered
 car  and others produced more noise.  Also, the diesel-powered  cars,
 except the Mercedes, meet the proposed 1978 California noise standards
 of 75 dbA.   The Mercedes  car exceeds the proposed 1978 California
 standards by  2 dbA,  and the Capri PROCO exceeds these standards by
 dbA.
          A comparison between diesel-and gasoline-powered cars of
 the  same make are shown in Figure 11,17.   The noise levels of  the
Mercedes 220D diesel and  220 gasoline cars are shown  in Figure 11.17
 for different driving modes (Ref,  98, p.  773).  The diesel produces
noise levels of 1 dbA to  5 dbA higher than the gasoline engines.  The
diesel car is particularly noisy during engine start up and idling.
The noise levels  of  the Peugeot 504 diesel car are higher than the
*SAE -- Society of Automotive Engineers

-------
                              169
    80
03
-a
75
—
O
z
ct
    70
    65
       T>

       O
           3)
           CC.
           Q.
           O
                    O
                    O
                    in
                     o
                     4>
                              o
                              (N
                           0)
                          T3
                           V
z
c
                                             (
                                                        o
FIGURE  11.16  Exterior Noise  Levels from Different  Cars,
Source:  Reference 94

-------
                      // Diesel Engine
                                                 I	j Gasoiing Engine
m
T3
LLJ
LLJ
CO
CC
O
X
LLJ
    80
70
    60
    50
    30
                                                                        2
        Engine     !d!e       Vehicle Start      St V20    31 mph   62 mph   44 mph
        Start              normal     quick    § 49     3rd G.    4th G.    4th G.
FIGURE 11.17   Comparison of  Exterior Noise  Levels  for 2.2 Liter
Mercedes Gasoline  and Diesel Cars.
Source:  Reference  98

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                                              11. 8

                 Comparison. Between. Exterior and Interior Noise Levels o£
                           Diesel-and-Gasoline-Powered Cars


Date Tested
SAI J986a
Accel Driveby
Exterior
Interior ,-, ,
1 1 )
Blower On v '
Off
48,3 km/hr Driveby
Exterior
Interior ,, .
f i \
Blower On v '
Off
Engine Idle/,,,
Exterior
Interior . -.
Blower On ' ^
Off
Datsim
Nissan
3-6-74


74.8


84
83.3

63.3


71.3
69.5

79

67
66.8
Mercedes
220D
3-5-74


77


78,8
74,3

62


73.5
63.5

66

71.5
51.5
Capri
Std
3-6-74


73


82.3
81.5
o\
58. 1W


70.5
65.8

63

70
54
Peugeot
504D
3-26-74


70.8


80
78.5

61.3


72.3
66.5

68

70
52.3
Opel
Rekord
3-26-74


67.5


73.8
73.5

62.5


70
69

72

70
53.3
Capri
PROCO
3-26-74


76


83
83

58.5


72.3
70.5

63.5

71
66
Capri
Std
3-26-74


73.3


83
82.5

58


71.8
66.5

57.5

70.5
53
(1)   Windows Up,  Fresh Air Blower on High

(2)   at 7.62 m

(3)   at 2.54 m
                                                                              REF 94

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                                   172
PeugeoL 504 gasoline car by 4 dbA during idling and 2 dbA at  31 mph.
The two cars have equal noise levels at 50 mph and 62 raph.  At 74 mph,
the diesel car is noisier by 2 dbA, (Ref. 98, p. 839).
          Table 11.8 also shows the results of many tests conducted
by Southwest Research Institute according to the Federal Clean Car
                  94
Incentive Program.   These results also show that the exterior drive
by and idle noise for the diesel cars is higher than the gasoline
powered cars,
                      109
          A comparison    between the steady-state interior noise
levels (A-weighted-dbA) of three diesel vehicles and those of a 1974
Torino and a 1974 Pinto 2.3L are shown in Figure 11.18 for speeds
ranging from 20 mph to 60 raph on a smooth asphalt road.  The results
show that the Torino is fairly quiet compared to the diesels, but that
the Pinto has nearly the same noise levels.
          It should be noted that the interior noise depends to a
great extent on the packaging of the engines, the structure of the
car,  interior design and blower noise.
          Table 11.8 shows that some diesel cars have lower interior
noise levels than gasoline cars and that this noise level depends on
whether the blower is on or off.
          The noise level of diesel engines may be reduced by
modifications to the fuel injection system, changes in injection
timing,  use of pilot injection, structural changes, basic changes in
engine design (such as using more cylinder of smaller bore, etc.),
intake and exhaust-manifold modifications, and engine isolation
techniques,
      c.   Odor -- The odor produced by the diesel engine is caused by
products  of the auto-ignition process.   Even gasoline engines produce
odor  if  they run on or "diesel".
          Little research work has been done to define which of the
stages of the auto-ignition process produce the characteristic odor.

-------
                                         173
    80 r-
co
TJ

0
LLJ
01
_l
LU
>
LLJ
LLJ
01
CC
O

-------
                                    174
One research program, using n-heptane-air mixtures, in  a motored  CFR
engine, indicated that odor is the result of quenching  the  second  stage
                                          97             94
(cool flame) in the auto-ignition process.    Table 11.9    shows
the results of a comparison of the exhaust odor from four diesel -
powered cars, two gasoline cars and a PROCO Capri car.  These exhaust-
odor results are for 10 driving modes covering the whole range of
loads and speeds.  The averages of all 10 modes show that the odor
from the diesel cars is, in general, higher than that from  the gasoline
or PROCO cars,
          The use of exhaust-catalytic converters to reduce odor,
                                                               114
and other incomplete combustion products in the diesel  exhaust,      is
still in the research stage.  It is not expected that it will be
applied to the actual engine in the near future.
          Further basic research is needed to study odor control,
      d.  Low _power-weight ratio — The diesel engine produces less
power than the gasoline engine of equal displacement, for two reasons.
First, the overall fuel/air ratio in the diesel is always leaner
than the stoichiometric ratio.   The limit to the increase in fuel/air
ratio is smoke production.  Second, the maximum rated speeds in
diesel engines are less than in gasoline engines.  The  limit here is
the short time allowed for fuel injection, evaporation, mixing and
combustion for proper engine operation.  Mechanical-stress considerations
also limit the speed of the diesel engine.
          The low power/weight ratio causes the diesel-powered car to
take a longer time for acceleration.   Table 11,7 shows  that time for
acceleration from 0 to 60 mph is 13.7 seconds for the Mercedes 2.3L
gasoline engine,  and 24,6 seconds for the 240D diesel car.  For the
Peugeot 504 diesel this time is 23,6 seconds, and it is 16.2 seconds
for the 504 Peugeot gasoline engine.

-------
175
TABLE 11.9
Comparison of Odor from
Type
Fuel
Diesel



Gasoline


Car
Datsun-Nissan W
S
Mercedes 220D
Peugeot 504D
Opel Rekord
Ford LTD
Standard Capri
PROCO Capri
Diesel -and Gasoline -Powered Cars
Six Steady
States
3.4
3.2
3.0
5.2
3.9
1.5
3.0
1.0
Idle
2.9
2.7
3.1
4.8
3.3
1.2
3.3
0.7
Three
Trans ,
4.7
4.6
3,7
5.7
4.1
1.5
2.9
1.6
All Ten
Conditions
3.8
3.6
3.2
5.3
3.9
0.6
3.0
1.1
REF 94

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                                   176
          Turbocharging is an effective tool for improving the power/
weight ratio of the diesel engine,  Turbocharging increases the
maximum power, torque and rated speed of the engine.  This improves
the acceleration characteristics of the vehicle.  The effect of
turhocbarging on fuel economy and emissions from the diesel-powered
car is presently being studied by many manufacturers.  The present
attempts are being made by adding a turbocharger to existing diesel
engines without lowering their compression ratio or optimizing the
injection and combustion processes.  The results of these attempts
are not conclusive.   The penalty in fuel economy at idling and low
loads as a result of turbocharging depends on the design of the intake
and exhaust systems  and the degree of matching the turbocharger to the
engine.   The effect  of turbocharging on the emissions during a FTP
cycle has not been assessed,

11,8  Conclusions
      a.   Technological feasibility of meeting the different emission
          standards:
          (1)   Diesel  engines,  currently mass-produced to power
               passenger cars of 3,000 Ib to 3,500 Ib3  can meet the
               1977  standards without EGR,  add-on exhaust treatment
               or feedback systems.
          (2)   There is no penalty in the initial cost,  maintenance
               cost,  or fuel  economy of these engines in meeting
               these standards,
          (3)   These diesel engines proved  to be the most economical
               power plants as  far as fuel  consumption is concerned
               and are as  reliable and durable in the field as the
               non-controlled gasoline engine.

-------
                         177
(4)  The total cost to the owner for one of these mass-
     produced 1975 cars, including initial, maintenance and
     fuel cost for 100,000 miles, will be less than that for
     the equivalent gasoline-engine car.
(5)  No extraordinary maintenance is required in the field
     during the useful life of the vehicle due to the absence
     of catalytic converters and feedback systems and the
     high durability of the diesel engine,
1978^ Nationwide standards
(1)  Based on the presently known technology,  it is not
     feasible for the diesel-powered car to meet the 1978
     NO  standards of 0.4 g/mi,
       Jv
(2)  If the NO  standard is relaxed to 1.5-2 g/mi,  many
              Jt
     currently mass-produced, diesel-powered cars would be
     able to meet the standard without any penalty in initial,
     maintenance or fuel cost.  Thus, the diesel-powered
     car would be superior to the gasoline version in total
     cost to the customer, and in reliability and durability,
(3)  With the application of EGR, injection-system modification
     and injection retard, it may be possible for currently
     produced diesel-povered cars to meet NO  levels of
     1.0 g/mi,,  but this may result in a penalty of 5% to
     15% in fuel economy and power.   The effect on
     durability of the engine has not been assessed.
(4)  Levels of NO , slightly less than 1.0 g/mi (but not less
                 it
     than 0.6 g/mi) might be reached by diesel-powered cars
     if sufficient research is conducted to optimize all the
     NO -control techniques.

-------
                         178
Problem areas
(1)  Intrinsic problem areas in the diesel powered cars
     which deserve further research are;   participates,
     odor, noise, and lov power/weight ratio.
(2)  The future standards for the nonregulated emissions
     should of course,  take into consideration the harmful
     effect of the pollutants rather than the total mass
     of the emissions.   For example, one  gram of aldehydes
     may be more harmful to the health and environment
     than one gram of paraffinic hydrocarbons.  Also, the
     total mass of the  particulate emissions may be high
     in the exhaust of  one type of engine,  but the mass of
     harmful species (such as BAP) may be low,
(3)  The relaxation of  1978 NO  emissions should be decided
                              •x.
     on as soon as possible.   The lead time needed for
     manufacturing is on the order of  five  years.

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               12,  ALTERNATIVE POWER PLANTS FOR AUTOMOBILES

12,1  introduction
      Activities in alternative power-plant development for automobiles
have continued in the two years since Reference 116 was written.  Many
of the problem areas have been more firmly stated and some of the less
applicable power plants have been weeded out.  The engine characteristics
and development times have become more firm.  It is clear that there are
no high-performance alternative power plants that can go into mass pro-
duction before the 1980's.
      Alternative heat engines in their major forms are gas turbines,
Stirling engines, and Rankine engines.  These can be categorized as
continuous-combustion engines in which a fire is established and heat
is continuously supplied to the system until power is no longer needed.
There are a number of other engines that fit into the spectrum repre-
sented by these three major types, such as several forms of reciprocating
Brayton-cycle engines and super-critical-fluid Rankine cycles.  In this
Section, concentration will be with the major types.  These heat engines
can use energy stored in the form of liquid or gaseous fuel.  Also, the
Stirling and Rankine engines can use energy stored in any fuel and in
the form of heat.
      Storage batteries have been used extensively for over a century,
and these can be used in modified form for powering automobiles without
the aid of heat engines.   Also, flywheels have been used for over a
century, but more recently they have been used to supply power to the
drive wheels of busses.  With the use of new materials and recent
technology, high-performance flywheels can now be designed to be used
directly, or as a mechanical energy-storage system for powering an
electrical drive for automobiles.
      Hybrid systems are combinations of two or more different kinds
of power plants or of different versions of similar power plants.  The
aim of hybrids is to allow the complete system to perform, according
to the best features of each part.  Those hybrids that have
                                  179

-------
                                   180
been  given  the most  attention  in  the  last  few  years  are  battery-heat
engine  combinations.   Some consideration has also  been given to
combining two different kinds  of  batteries  in  an electrical  drive
sys tern.
      Alternative engines for  automobiles  are  in an  embryo state of
development.  While  gas turbines, Stirling  engines,  steam engines,
advanced lead-acid battery power  plants, and electric-heat engine
hybrids have been running in automobiles,  there are  none that can be
considered  as suitable prototypes for manufacture.   That is,  the
developers  themselves have indicated  that  at least another generation
of development is required before they will be satisfied that their
particular  power plant has demonstrated its full technical,  economic
and customer-satisfaction potential.  There are no flywheel  or
flywheel-hybrid power plants presently operating in  automobiles;
and there are no high-performance, battery-powered systems running
in automobiles,
      A few examples of experimental continuous-combustion engines
have  progressed beyond the dynomometer testing stage and are presently
mounted in  automobiles that are either available, or very nearly
will  be available, for test driving.  These include  two Stirling
engines (United Stirling and Philips), three gas turbines (Williams
Research and Volkswagenj Chrysler, and General Motors), and  eight
Rankine engines (Carter, Scientific Energy Systems,  Steam Power Systems,
Pritchard, Thermo-Electron,  Aerojet, Kinetics Corp., and Williams
Brothers).  Other cars, such as GM's steam cars and Rover's gas-
turbine car, have operated in the past but their development is now
dormant.  Others, such as the Paxve Rankine engine car, are  in a
temporary state of dormancy.   All of the active engine programs
winose goal is mass application to automobiles are aimed at
•..onionstration and upgrading.   Measured performance and engine
    actcristics that are considered as the final state of

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                                    181
development do not exist.  Therefore, while some data and
quantitative characteristics are reported herein, they are not  to be
considered as representative of fully developed engines.  Most  of
the information is, per force, tempered by judgment of the source
and of the panel of consultants; the conclusions stated throughout
this Section are judgments of  the latter.
      Similar judgment has been rendered in some cases concerning
batteries and electric drives.  This is particularly true for the
high-performance batteries still under development.  Also, the
electric drive situation is in a state of flux with final choice of
system not made in most cases.

12.2  Gas Turbine
      In comparison -with aircraft and industrial gas turbines,  the
automotive gas turbine has a much more difficult job and has
necessitated considerable development effort.  Efficiency, low
idle fuel consumption, good off-design performance,, and fast response
requirements have forced the developers to turn their attention to
higher turbine inlet temperatures, simple yet efficient rotating
components and highly effective regenerators.  Thrust is not needed
as in jet engines.   Steady load as in industrial gas turbines is the
antithesis of automotive gas turbine use.  These aspects make the
automotive gas turbine unique.
      General Motors demonstrated attainment of 1978 emissions
                 122
standards in 1974.     It used an existing engine (GT 225)  in an
automobile weighing 5,000 Ib, running through the federal  driving
cycle on chassis rolls.   A large variable-geometry combustion was
fitted and was manually controlled from an off-vehicle console.   All
four tests made were reported as being below the 1977 limits;

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                                  182
            HC                    CO

                            grams per mile


            0.02                  2.7                 0.32


from cold starts using diesel fuels.  Other developments also show
                — 1 9 R
low emissions.  ~    Above 2.0 g/mi NO  a fixed combustion geometry can
                                      j*t

be used.  Achievement of NO  as low as 0.4 g/mi requires variable geome-
                           ^      -I O C 1 O t

try, although the Zwick combustion   *    uses only a very simple flow-


splitter concept.  This combustion was tested on a small gas turbine and


yielded the following emissions (translated from g/kg) :



            HC                    CO                  NOx

                            grams per mile


            0.26                  2.7                 0.12


       There was general agreement among all companies visited that


there was no problem in meeting the hydrocarbon and carbon -monoxide


limits with existing gas turbines, and that a level near 2.0 g/mi NO
                                                                    X

could he reached with fixed -geometry combustors.  The use of variable-


geometry combustors to reach the lower NO  limits would entail addi-


tional manufacturing costs of at least $40 (Ford projection) because


of the more complex burner and control system required.


       Ford, Chrysler, and GM were in. agreement that gas -turbine


engines, which would be available for production in the 1980's, would


have fuel consumptions in. the federal driving cycle lower than the


average of spark-ignition engines controlled to meet 1974 emissions.

                                                        129
Ford, in particular, forecast sharply lower consumption.     It felt


that the miles per gallon of production vehicles would be 40% higher

-------
                                   183
than that of 1974 spark-ignition-engine  cars  in  1985  and  130% higher
in 1990  (3,000°F TIT).  Poor  idle fuel consumption has  been  the
chief cause of poor mileage in urban driving,  and the higher TIT
levels projected tend to reduce  this deficiency.  Calculations
verify that with Ford's projected component performance (turbine
efficiency = 91%, regenerator effectiveness =  92%, compressor
efficiency = 85%, leakage = 2%?0, and pressure  drop =  10%), and with a
turbine  inlet temperature (TIT)  of  2,500°F, that the  projected fuel
economy  is reasonable to obtain.  The component  efficiencies listed
above are on the optimistic side, which  implies  that  very careful
development will be required  to  achieve  the above-mentioned fuel
economy.  Ceramic turbineSj nozzle  rings, combustors, and heat
recovery units are required to achieve the full  advantage in fuel
economy.
      The most significant change in the outlook for  the gas turbine
                                                           122 129-131
results  from the general agreement  among U, S,  manufacturers  *"'
that it  can be a technically  superior engine to  the spark-ignition
engine at least down to 100 hp,  and probably to  75 hp.  If Ford's
predictions are confirmed, a  75-hp  gas-turbine engine would have a
lower fuel consumption than a 40-hp spark-ignition engine, thus
tending  to rule out the use of minicars as a necessity  to reach high
mileage.
      Moreover,  gas turbines of  any size are intrinsically long-life
engines,  as demonstrated in the  aviation industry.  Their use will
give an  incentive to the design  of  long-life chassis and to the
consequent reduction in materials use.   In contrast, spark-ignition,
internal-combustion engines as used in automobiles are  comparatively
short-life engines,  with life decreasing as size decreases.
      The configuration of the gas turbine for automotive use, which
has been regarded as standard, has a centrifugal compressor, one or
two rotary regenerators, a combustor, and an axial turbine as the

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                                 184
so-called  'gasifier' section, and a separate-shaft axial turbine with
                                                 130-136  „...,.
variable-angle nozzles forming the power section.         This basic
configuration was used by GM in their demonstration of low emissions.
                                                               137
       In  the last  two years, there has been increased study of
                                                      122 129
and acceptance of the single-shaft gas turbine concept   '    which
achieves considerable simplification by dispensing with the power turbine,
However, some form  of infinitely variable transmission is required to
take power from the shaft driving the compressor, whose speed must be
maintained at above 50% design speed.  Various types of transmission are
being studied, but nonehas yet been demonstrated with a single-shaft gas
turbine.
       Present U.S. vehicle turbines use peak-cycle temperatures in
the range of 1,850°-1,925°F.122'129~131  It is generally accepted129'131
that 2,200 F is achievable with existing technology.  It is anticipated
that temperatures will be increased over the next six years to
2,500°F,   '    and possibly to 3,000°?,  "  The most likely means for
withstanding these  temperatures in the combustor, nozzle and turbine
is the use of silicon carbide or  silcon nitride.  Ford, with in-house
and ARPA funding, is developing a dual-density turbine wheel with a
hot-pressed hub and molded blades, both of SiN .  Indicative of the
increasing effort on ceramics for gas turbines are References 138-1425
showing the high potential of silicon carbide and silicon nitride.
Alternative ways of reaching high temperatures are to use gas or liquid
cooling and to employ coated refractory (molybdenum) alloys.
       Design of gas turbine for  the high inlet temperatures required
to achieve competitiveness with gasoline engines is a new science
that is some years away from maturity.  Casting and firing ceramics,
use of refractory metals, and strong cooling of blades and nozzles
are all expensive at this time.  They are all in the early development

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                                  185
stages for automobile engines.  There is no established certainty that
any of these methods of utilizing high turbine inlet temperatures can
be developed for a low-cost engine.  Also, there is some feeling among
development engineers that the potential performance gains associated
with higher turbine inlet temperatures will be dissipated by increased
                                          143
losses due to the reduced Reynolds number.
       The cost of anti-friction bearings can be high,  Chrysler uses
                         130
plain bearings presently.     Gas bearings of the foil type seem
                                   129
attractive as a future development.
       Present problems with ceramic heat exchangers have been
identified as due principally to sodium substitution from road and
         129
sea salt.     Hew ceramic materials will be required.  Some potential
candidates have been found and are being evaluated.
       Studies have been made, and are continuing, on gas-turbine
costs to the consumer.   *    f     Above 150 hp, it is possible that
                                                           131
they could be near competitive with spark-ignition engines,    but they
                                          143
become much less competitive below 100 hp.     The cost structure is
not clear at this time and must be made firm with more experience in
small gas-turbine manufacturing.
       The estimates made in the April 1973 report (Reference 116) still
seem valid—that limited production of gas turbines could start in 1982
and mass production in 1984.  These estimates assume an incense and
continuing effort.
       The costs of changing the automobile industry's 46 engine lines
to gas-turbine production (ceramic components) have been estimated by
                                                          1?9
Ford to be $250 million each, or a total of $11.5 billion.     This
cost would be additional to the normal costs of production changes.
Ford's estimates show the possibility of the investment being equalled
by the value of the fuel saved  (at about 65 cents per gallon) within
five years.

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                                  186
       All foreign manufacturers appear to be well behind U.S. companies
In automobile gas-turbine development.  Their predictions are also much
more conservative; reflecting U.S. views of five or ten years ago.

12.3  Rankine-Cycle Engines
      Rankine engines for automobiles are basically of four types:
steam with positive-displacement prime mover, steam with turbine
prime mover, organic fluid with positive-displacement prime mover,
and organic fluid with turbine prime mover.  Another broad category
of Rankine-cycle engines--those using liquid metals--is not being
considered for automobiles.
      Steam has been used the longest of any of the available working
fluids, and reciprocating prime movers have been used the longest with
steam.  Other fluids were investigated as the need developed for high
power density in the prime mover and for efficient low-temperature
cycles.  Rankine cycles are subject to optimization for peak efficiency,
or reduced size, or reduced cost as a function of fluid and design
conditions.  Conclusions based on Rankine-cycle optimization and hard-
                   116,127,145-164      ,           ,,, ,  ^
ware investigations                are that steam will lead to the
lightest and most efficient simple Rankine engine for automobiles.  The
efficiency of simple steam cycles is generally limited to about 257,
at the best operating conditions; organic Rankine cycles are generally
limited to about 20% at the best operating conditions.  Thus, organic
fluid power plants have boilers a minimum of one quarter larger than
equivalent steam plants, and the condensers need to be at least one third
bigger.  Many organic fluids also have thermodynamic properties that
require recuperators to be built into the power plant.

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                                  187
      The last two years have seen significant development strides
in steam automobile engines.  Efficiency has been pushed to near
the probable limit for simple steam engines in at least two development
        147,148
programs     , and in one of these development programs, the weight
and volume have been brought down to be near competitive with the
                              147
small engine that it replaced.
      Also, the latter engine, described in Table 12.1 (Carter) has
demonstrated in. actual tests that the 1978 emissions goals have been
met with competitive mileage in an auto having an overall weight of
2,750 Ibs:
14.9
HC
CO
NO
X
WT
MPG
0.399
1.08
0.33

415

g/mi
g/mi
g/mi

Ibs
This steam engine has been fitted into a small car (a VW station
wagon).  Figure 12,1 shows three photographs of the car and
components.  The engine filled the compartment of the air-cooled SI
engine it replaced.  In addition, a 35" x 16" x 2%" ram air radiator
mounted at the front of the car is satisfactory to 60 mph.  A small
additional radiator with a fan is mounted in the engine compartment.
Fixed cutoff is used.  A transmission and variable boiler pressure
is used to vary power and torque to the wheels.  The boiler
pressure is allowed to change in response to power demands.  Boiler
pressure, water rate, steam temperature, and F/A ratio are all
controlled.  These innovations lead to simplified controls.  The
steam is held closely (+15 P) to design temperature at all times to
allow the efficiency to be as high as practical over the operating
range.   The prime mover is a very light piston engine using a unique

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                                                      TABLE 12.1

                                              Steam Engine Characteristics
HP
HGT
Fuel Consumption
Emissions
Type
SPS
65
940 Ib
incl, trans ,
1.2 Ib/HP hr
BSFC
0,14 HC, 1.2 CO,
0.22 KOx
(Projected)
4 Cylinder
Double Acting
SES
150 (gross)
904 (Projected)
10 MG
0,18 HC, 0.43 CO,
0,18 NOX
(Predicted)
4 Cylinder
Uniflow
Aero let
60
970 Ib
incl, trans.
0,95 BSFC
(best)
0.1 HC, 0.5 CO,
0,17 KOX
(Projected)
Turbine
(single-stage
Carter
90
417,5 (with
front condenser only)
14.9 tnpg FDC*
(0.67 BSFC to
vehicle dynamometer)
0.4 HC, 1.08 CO
0.33 NOX
(Measured at EPA)
4 Cylinder
Uniflow
Thermo -Electron

111.1 (Fluorinol - 85
•working fluid)

1.3 Ib/HP hr
(10.2 mpg-FDC)
0.17 HC, 0.21 CO,
0.275 NOX
(Predicted)
4 Cylinder
Uniflow





                                                              impulse)
                                                                                                                         CO
                                                                                                                         CO
S team


Condenser
      Compound

Hi Pr Bore = 2.125" (2)

Lo Pr Bore = 4,25 (2)

Stroke = 2.125"

RPM - 2,400 (max)

Valve - variable cutoff
      - variable timing

Monotube boiler
      - 700 pph

      1,000 psia
      @ 850  F
      6ft2
                                           3 1/2" bore
                                           3 1/2" stroke
variable cutoff
variable timing
Monotube boiler
  - 1,200 pph
1,000 psia
@ 1,000 °F
6.32 ft2
                                                         4.42" bore
                                                         3,00" stroke
Monotube boiler
  - 660 pph
500 psia
@ 1,000 °F
3.9 ft2
                                                                              Fixed cutoff
                                                                              Monotube boiler
2,000 psia
@ 1,000 °F
      2
3.5 ft  (approx)
for front condenser
6 ft  (approx)

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                              L89
FIGURE 12.1
  Rear View of VW with Carter Steam Engine Mounted.   The Grill
  Covers the Boiler Stack and the Rear Condenser.





  The Prime Mover Showing the 4 Cylinder.

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                      190
Continuation of FIGURE 12.1
     The Boiler-Burner Assembly.




     Source:  Reference 147

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                                  191
valving  system and  uniflow  design  that  lead  to  high  prime-mover
efficiency.  Extremely good lubrication is achieved  which  promises
to lead  to very  long  prime-mover life.   A centrifuge is  used  to
separate oil from  the feedwater so that oil  will not affect the
design or operation of the  boiler  and condensers.  The flow chart
for  this engine  is  indicated on Figure  12.2,
      The demonstrated starting time to high-speed idle  is less  than
15 seconds.  Time  to  reach  driving power is  27  seconds.  The  emissions
of this  engine are  not the  best that could be expected,  but it is not
because  of the engine design.  Rather,  the application of  principles
                                                 1 O£ I o-7
of combustion design  developed in  other companies    *  could  easily
reduce the emissions  further without affecting  the engine  in  any
significant manner.
      Good strides  were made in the development of another steam
                                148
engine designed  for a larger car*    This engine is  presently
mounted  on a dynamometer being readied  for simulated driving.
Steady-state measurements indicate that the  mileage  will be near
competitive to 1974 vehicles.  Very good emission results  are also
indicated.  Table 12,1 describes the SES engine.
      A  third steam engine  presently starting driving tests in a
small vehicle (2,500  Ib) demonstrates very good emissions  in  its
                 146
preliminary tests.     Also, mileage appears  to be approaching that
for emission-controlled, gasoline-engine-powered automobiles of the
same weight.   Table 12.1 describes  the  SPS engine and the
characteristics of  an advanced version  as anticipated by SPS,
      The Aerojet steam turbine engine  built for the "California Clean
Car" is also described on Table 12.1.   It is not as  far along as the
others.   The Thermo-Electron organic fluid engine is also described
on Table 12.1.   This engine development was being supported by EPA
and Ford.  Ford has declined to fund this program further.

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                                          192
                                                Fuel In —>
                                         Air In
                               Water into.
                               Control
       Oil Return
       to Crankcase


Water
Pump
               Fuel into
               Atomizer
                    I—. Steam
                  _j_ Out Boiler
                                                        Pressure Container
                                                        Fy«l~Air Container
                                                        Temperature
                                                        Container
                                                Variable Pressure Boiler
          Water into
          Boiler

   Plus Gas
   Exhaust           _
Throttle Valve    -HX1
(control purposes only)
         12.2   Flow Chart.
Source:   Reference  L47

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                                  193
      Cost is the major unknown factor for Rankine engines.  With the
continued development of manufacturing techniques for boilers, with
the use of the simple controls already demonstrated on one of the
                 147
existing engines,    with the use of burners having emissions as low
   ,    ,       '    ^  t ,  ,     126,127,144,148,149    ,   . ,   ,
as has been demonstrated already,                    and with the use of
                                                                     147
the lightweight, simple, well-lubricated prime mover discussed herein,
the cost of the engine probably can be brought down to within 507. to
100?o of the equivalent pre-control spark-ignition gasoline engine.
The prime movers and the accessory drives could, conceivably, be less
costly than the equivalent SI engine.  The control system demonstrated
                                                 147
on the small steam engine in the VW station wagon    is the simplest
of the Rankine-engine control systems being developed on EPA or State
of California contracts.
12.4  _S_tjirling_ Engines
      Basic findings on the Stirling engine as reported in leference 116
are still valid with some minor modifications.  Developments in Stirling
engines for automobiles over the last two years        have centered
                                                                      165,166
around installing two experimental versions in marketable auto frames,
A 175 hp engine has been operating on a dynamometer in the Netherlands
and will soon be mounted in a Ford Torino,    and a 100 hp engine has
                                                          166
powered a Ford Pinto to as high as 65 mph on a flat track.     A CVS
test simulation indicates emissions of an intermediate-size auto will be:
            HC                    CO                  NGx       MPG
                            grams per mile
            0.20                  1.20                0,14      14,7
These engines are described in Table 12,2,

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                                      193a

                                    TABLE 12.2
HP
Emissions
Type
Mechanism
Fluid
Rod Seal
Control
Peak Temperature
Engine Efficiency (Peak)
  (see plot below)
Radiator Area
Market Goal for
  cp^cific Engire
S_Eir 1 ing _ Engine Description

Philips
170
0.20 HC, 1.20 CO, 0.14 NO
double acting
swash plate
hydrogen
roll sock
variable mean pressure
1400°F

32%
automobile
       Fuel Economy Map - 4-215 Engine
           60 r-
United Stirling
100

double acting
V-4, crankshaft
hydrogen
rod clearance control
variable pressure amplitude
1400°F

25%
3 ft2 <3" thick)

replaces small diesel
       o
       tr
       O
           10
                          1000        2000        3000
                                   ENGINE SPEED (rpm)
                                4000

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                                  194
      What is now apparent for Stirling engines is that by tailoring
the efficiency slightly,  an engine of appropriate power for an
existing automobile can be of low enough weight and size, and have
sufficient response time to be indistinguishable from gasoline-powered
automobiles.    '      They are very quiet, the fan and blower noise being
the largest contributor to noise; they are very smooth in any workable
configuration; they can be made to be very low-emissions engines,
they will have low fuel consumption,  somewhere close to a nonemission-
controlled diesel engine;    and they can have exceptional life.  On
the other hand, the radiator will be  harder to fit into a standard
automobile.   *     Cost and production problems have not been resolved
so that the present cost projections  show competitive values to diesel}
but not to spark-ignition, engines.
      Predicted emissions were reported in Reference 116 and still
apply.  No direct measurements with Stirling engine-equipped cars have
u      j              i_    .   -     u  TJ u       i   169-172
been made.  However, the emissions should be very low.
      It is also apparent that the present developers feel that they
are at the threshold of the next steps in dramatic improvement.       *
171,173,174  -     .   ,    .               ,         _  ...  166 .
             These involve incorporating cheaper materials,    improving
the power control system to be cheaper and more efficient,   3    and
more completely integrating the engine into the power train to better
meet the driver's demands.     They are now better able to cope with
optimizing for different applications such as automobile duty, medium
duty, and heavy duty-  Much remains to be done, and at present rates
of spending (about 230-men average Load over the world), it will still
be three to four years before an acceptable automobile engine will be
in existence.
      The Stirling engine must still  be regarded as an experimental
engine for automobiles.  While the basic engine is understood, there
are a large number of design compromises needed (and unsettled at

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                                  195
this time) before the proper development direction can be chosen for
particular applications.  For instance, it is known that fully
metallic engines can be of high efficiency iind be quite small and
light, but they are expensive.  On the other hand, ceramic parts
should fit very well into several places of the Stirling engines.
This should ultimately lead to inexpensive engines.  However, it is
not clear which parts will be cost effective to switch to ceramics
in mass production, there are no suitable ceramics in mass production
for use in such applications, design compromise to use ceramics in
such engines is just starting to be a known art, and efficiency
versus size of Stirling engines as affected by ceramics is not yet
assimilated into the technology.  The ceramic work being done on
behalf of gas turbines can also be applied to Stirling engines.
      a.  Stirling engine^ characteristics -•- The objectives for design
of a workable Stirling engine beyond that required for any positive
displacement engine, primarily are as follows;
          prevent fluid leakage from inside the loop to the outside
          past the power shaft or rod to keep the engine operable;
          keep all volumes outside the swept volumes as small as
          possible for highest specific power density;
          minimize pressure losses as the fluid moves back and forth
          through the heater, regenerator, and cooler for high
          efficiency and greatest power control range;
          handle as much fluid as possible for best specific
          power density;
          operate at as high a peak temperature as possible for
          high efficiency;
          prevent loss of heat from the hot side to the cold side for
          high efficiency.

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                                  196
These translate into a requirement to use pressurized hydrogen or
helium as the working fluid.  The classic problems of Stirling
engines that also arise  from the above list of requirements are;
          (1)  Heater head:
               Requirements are small volume, large area, low fluid
               pressure losses, high-temperature materials.  Usually
               forces the use of H  or He under high pressure as
               the working fluid;
               Makes thermal stress a severe problem;
               Makes for high-cost materials and construction
               technique.

          (2)  External seal and working fluid diffusion losses:
               Requires either very low loss so one charge lasts a
               tolerable time without power loss, or requires that
               the engine be rechargeable.
          A third classic problem arises when consideration is given
          to changing power level:
          (3)  Power control:
               Requires very rapid method of changing fluid quantity
               and/or method of changing pressure amplitude variation
               with a fixed-fluid quantity, to be workable at any
               engine speed.
          All of these problems contribute to the potential cost.
          Practically all of the development work going on at this
time, beyond making the engines operable in automobiles, is toward
technologically suitable solutions of the three major technical
problems.   Designs which appear suitable for lowered cost are to be

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                                  197
developed later from  these  solutions,  so  that  lower  engine  costs
follow by normal cost reducing methods.   One developer  is aiming  for
a car installation  that will have run  a total  of  50,000 miles by
December 1975.
          It  is worth noting that the  safety of automobiles has
been checked when the hydrogen-working fluid inventory  has  been lost
into the engine compartment.  No significant hazard  appears to exist.
      b.  Future possibilities — It is apparent  that much  ingenuity
has yet to be expended on heater-head  design.  This  thinking is being
tempered by the great desire to incorporate ceramics into many parts
of the design for very high-performance engines.  However,  the only
ceramic part  in any existing automobile-type engines actually
running is the rotary air preheater.   Time limitations  imposed by
the automobile company contracting for Stirling engines (Ford)
have precluded including extensive development work  in  ceramics at
this time.
          The control situation is till pregnant with concepts yet
to be tried.  The ones being used presently are the  variable-mean-
pressure type, and  the variable-pressure-amplitude type.  A
simplified variable-amplitude type makes  use of fewer valves, with a
goal of simplifying to one  set of valves  for control of all chambers.
Philips is reconsidering the variable-pressure control  to see if it
can be improved.  MAN is working on a  proprietary system that would
bypass the major drawbacks  of the variable-amplitude and variable-
pressure systems.
          Sealing appears to be a tractable problem, more in that it
be designed around,  as well as partially  solved by5  direct attack.
United Stirling uses a sliding seal with  provision for  onboard
hydrogen makeup.  Yearly leakage of a  100 hp  engine would be about
4 Ib of hydrogen based on their existing  data  (about 100 refills
per year).   Philips uses the roll-sock seal for stopping leakage

-------
                                  198
 at  the  seal, and only a yearly check of hydrogen inventory  Is  needed,
      The  prime movers are all presently piston-type,  positive-
 displacement devices.  At least one patent has been issued  to  an
 auto company for use of rotary positive-displacement devices.  Assuming
 the mechanical seal problem associated with such configurations can
 be  solved, development could lead to an engine of small overall
 prime mover size simply because the drive mechanism would now  be
 better  incorporated into the package design.  The largest part of
 the prime  mover sections of existing Stirling engines  is the drive
 mechanism, be it rhombic drive, connecting rods and drive shaft,
 or  swash plate.  A V-4 engine is fitted into the Pinto, and a  swash
 plate engine is being fitted into the Torino (Philips 4-215 engine).
      One  additional concept worth noting is that one developer
 thinks  highly of a method that incorporates a variable swash plate
                                                                        165
 into the drive design that would essentially eliminate the  transmission,
      The  Stirling engine leads itself well to operation with  stored
 head.    The engine can be combined with a thermal storage system
 (thermal battery) to operate either with sensible heat, heat of
 fusion, or both, depending on the heat storage material.  One research
 group believes that small cars using Stirling, engines with thermal
                                             l65'
 storage units are practical for urban driving.    Projected heat
 storage capacity using fluoride or eutectics of fluorides at
 550-S60°C range from 0,33 to 0.47 fcwhr per kg or 0.72 to 0,93 kwhr/dm,
About 35% of this is deliverable as mechanical energy.  The delivered
 energy density would be 50 to 70 whr/lb compared to about 10 to 12
whr/lb for the best existing lead-acid traction batteries.   This
 system would be a competitor to the small battery-powered urban car.
The BTU energy balance favors the battery system,  but the thermal
system can be lighter.   Costs of the thermal system are not yet
worked out.

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                                  199
12.5  Reciprocating Brayton-Cycle Engines
      These engines use reciprocating parts  to accomplish compression
and expansion.  The cycle  is basically  the same as for gas turbines,
and all of the thermodynamic options open to gas  turbines are open
to reciprocating Brayton engines:
      1)  Air working fluid, with heat  recovery,  internal firing
      2)  Air working fluid, with heat  recovery}  external firing
      3)  Air working fluid,  no  heat  recovery,  internal firing
      4)  Air working fluid, with heat  recovery,  external firing
      5)  H  or He working fluid, with  heat recovery, external firing.
Only the last one has been studied experimentally in the last few
years; types 3 and 4 have been in the patent literature for decades.
Thermodynamic performance demonstrated  to date on Type 5 is quite
poor (about 12%)} but an efficiency on  the order  of 2770-30% should
be attainable using the same materials, etc., that would be used in
                              176,177
the equivalent Stirling engine.       The Brayton engine has the
advantage that pressure losses due to small heat  exchangers can be
avoided and that power density is not sensitive to external volumes,
But, it has the disadvantage that one set of hot valves is needed,
Otherwise, the Stirling engine and externally fired Brayton engine
with H  or He working fluid have many of the same characteristics.
The Brayton engine has some design flexibility advantage over the
Stirling engine in that more freedom on pressure ratios exists.   This
may be an academic advantage, however,  since present Stirling volume
ratios appear near optimum.  Because the Brayton engine relies on
isentropic processes for compression and expansion instead of iso-
thermal heat transfer processes (as in Stirling),  and because the
Brayton engine uses a recuperator rather than a regenerator (as  in
the Stirling) for cycle heat recovery, the Brayton engine thermodynamic
efficiency runs somewhat lower than for a Stirling engine operating

-------
                                  200
         the same temperatures.  A recuperator transfers heat between
 two fluid streams with an effectiveness of 8570 or less except where
 large volumes can be tolerated.  A regenerator collects heat from  a
 hot fluid, stores it, and Later transfers it to a colder fluid with
 effectiveness that can range up to 98%.  The meaning of these trade-
 offs is  that the Stirling engine should be able to attain higher
 efficiency at the same or less cost, but that the design problems  are
 more difficult than for the reciprocating Brayton cycle.
      The use of air in reciprocating Brayton engines is possible
 from a practical point of view because the heat exchangers can be
 designed for air without compromising the engine power density and
 efficiency.   The operating conditions of the engine are limited,
 however, by the action of hot air on the materials of construction.
Whether  internally or externally fired the same limitations apply.
 Internal firing has the advantage of reducing heater size and cost,
but could Lead to poor emissions if the performance is to be
satisfactory.   External firing has the same limitations as for the
H. or He engines.
      If the problems associated with achieving a suitable Stirling
engine design of the conventional type prove insurmountable from a
cost point of view,  then the reciprocating, valved, Brayton engines
will be worthy of further consideration,

12.6  Flywheel Systems
      FLywheeLs of new designs offer the possibility of very high
                      178,179
energy storage density.        A flywheel  with sufficient specific
storage capacity to  drive a car in a conventional way requires a
sophisticated design,  a vacuum chamber to run in, and a seal and
vacuum pump  for maintaining the vacuum.   The drive requires an
alternator with a variable-speed,  variable-frequency type converter
or variable-speed,  constant-frequency converter with additional

-------
                                 201
control for electrical drive or an Infinitely variable transmission,
Thus>for the electrical drive, the drive system alone will cost
one and one-half to two times the engine and transmission it replaces.
                                              174
This is the same as for battery-drive vehicles.    In addition, there
is the cost of the flywheel assembly.  Unlike battery drives, there
is little probability that  the flywheel could be an easily replaceable
unit for quick change at a  service station.  Thus, the flywheel has
to be considered part of the automobile's first cost to the customer
rather than an operating cost as with gasoline or easily replaceable
batteries.  Flywheels and their vacuum chambers suitable for 200-250
mile range will probably cost on the order of an uncontrolled engine,
sized for similar service,  based on estimates available in preliminary
studies.    Special transmissions, vacuum devices, chargers and
controls, or electrical drives are additional.  Also, the demonstration
of such a system in an automobile, irrespective of cost, is several
years away.
      Use of an infinitely  variable transmission would bring the
power plant cost down to that of the flywheel assembly, the transmission,
a gearbox, and a charging motor.  The total cost may conceivably be
brought down to one and one-half to two times that of uncontrolled
spark-ignition engines if the flywheel assembly can really be made to
cost the same as an uncontrolled spark-ignition engine.  Demonstration
of this cost probability and demonstration of the flywheel system
in a vehicle would be required before it could be considered seriously
as an automobile drive.   The safety aspects of flywheel operation
will also have to be demonstrated in a vehicle, although the frangible
flywheel using glass fibers has been shown to disintegrate effectively
without problem when malfunctions occurred.  The emissions would take
on the nature of the central powerplant, similar to battery systems.

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                                 202
12.7  Electrically Driven Vehicles
      a.  Introduction -- The assessment of the performance of present
and  anticipated electrically driven vehicles as presented in Reference 116
requires additions and corrections in the light of new developments.
Recent vehicle systems studies,        battery and vehicle test pro-
     186-189   ,              .  ,           ,   ,    190-194  _
grains        and advancements in battery technology        allow a more
concrete appraisal of future vehicle capabilities.  The gasoline fuel
shortage experienced during the past year, as well as the rapidly rising
cost of crude oil, have provided a powerful spur for seeking alternative
power sources for transportation.  Electric vehicles, at least on super-
ficial examination, seem to offer potentially significant fuel savings.
(183,188,195,196)
          It is well understood, of course, that the use of electrical
drives in vehicles entirely removes the polluting source from the vehicle
and  transfers it to the central power plant.  The cleaning up of emis-
sions from power plants need not be considered here; this problem is
already receiving intensive attention.   The additional power demand by
electric vehicles seems not serious considering the unavoidable low rate
at which such vehicles could be added to the present transportation
scheme.  For instance, if all driving in the USA were by electric cars
                 12
(approximately 10   miles per year) requiring about 0.4 kwhr/mi, the
nighttime average electrical generating capacity required for charging
would be about 150,000 megawatts.  This is not much greater than the
present nighttime excess generating capacity in the United States.
Gradual introduction of electrical vehicles should result in demands
less than the excess capacity.
      b.  Batteries -- Results of recent test programs and of develop-
mental efforts lead to the following assessment of present and future
capabilities of batteries:

-------
                                  203
          (1)  The lead-acid battery is the only currently available
electric sotrage system for automotive traction with a reasonable cycle
life and cost per unit energy stored.  Its key limitation, energy storage
density, can be improved sufficient  (from 10 to 12 whr/lb to about 13
to 15 whr/lb) but this is not to permit application beyond rnarginal-
                                                     197
performance urban vehicles, delivery vans and busses.     Even if the
cycle life were to be extended to 1,000 deep cycles, the amortization
of the battery over its lifetime will lead to a cost of the battery
 i         +-,.<**           iu^i-    j 180-182,184
alone amounting to 3-5 cents per kwh delivered.
          (2)  Other battery systems with "intermediate" performance
                                                             187 1 90
will very likely become available within the next five years;   '
see Table 12.3,  Although these promise to provide two-to-threefold
improvement in energy density ; relative to the lead-acid battery, it
is unlikely that their cycle life can be sufficiently improved to
provide economically attractive energy storage cost.  However, because
the future Zn-NiOOH system may have good power capability, its applica-
tion in electric vehicles and perhaps in gasoline-electric or battery-
battery electric hybrids deserves consideration.
          (3)  Recent advancements in the technology of the solid
electrolyte (beta-alumina), as well as in other critical areas affecting
the feasibility of alkali metal sulfur systems, increase confidence
in the eventual technological feasibility of high-energy, high-power
                        182 192 195
density battery systems.   '   '     Prototype producing and testing
programs should provide definitive answers in the next three to five
years as to whether the alkali-oetal-sulfur batteries can provide an
economically viable solution to the energy storage needs of electric
vehicles.  Indications at present (Table 12.3) are that battery
amortization costs may achieve a level below I/cent/mile,  Current
work on the feasibility of battery schemes employing alkali-metal

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                                                                  TABLE 12,3
                                                   Batteries  for Electrically Driven Vehicles
System



Pb/H..SO ,/PbO *


7,n/KO!l,'KiOOH

Zn/Z«a2/Cl2.6H20
Fc/KOH/NiOOH

H /KOH/NIOQH
2
Li/LiCl.KCl/S

Li,Al/LiCl,KCl/FeS2

B-Alumlna
Na or S
Na— glass
Theoretical

whr/k§_

175


326

465
267

381

2,500

790


760

Best Present
Performance

wh/kg
22
to
26

55

70
36

65

150

120


90

peak
w/kg
100
to
^00
loo*-*
to
200
50
35

40

150

120


150

cycle
life
300
to
1,000

200

10
2,000

1,000

100

200


1,500

operating cost
timejyear §/kWh
1.5 30
to to
2 50

1 100

? ?
3 50

1 ?

0,2 ?

0,5 1


1 ">.


wh/kg
28
to
33
30**
to
35
110
44

80

330

200


180

peak
_ w/kg
100
to
.100
100**
to
200
100
100**
to
200
100

200

200


200

Anticipated
Performance
cycle
life
500
to
1,000
500**


500
500

3,000

1,000

1,000


1,000

operating
t line ,y ear

3


3

3
5

3

3

3


3

cost
$/kwh
40
to
50
30*| ,
tcr '
50
50
50
(1)
100
(1)
20
50
20
50

20
50

year
1976/
to
1978
1978*/
to
1980
I960
1978

1980




1980



 ~Data and estimates pertain to deep  (70-807=) discharge  at  1-3  hr  rate.   Range of numbers refer to range of usage.
--••Ranges refer to uncertainty.
 (1)  With metal recovery accounted for.

-------
                                  205
negative electrodes at lover temperatures  (in the range  of  200 C)
                           190
shows good initial promise.    Significant advantages in cell
construction technology and cost may be derived from operation at
this lower temperature level.  Production of significant numbers of
electric vehicles based on alkali metal batteries cannot be expected
before 1985 at best,
      c.  Electric drive train -- There are a number of viable
alternatives for motor and switch-gear systems suitable for use in
electric vehicles.  Systems studies and experimental test programs
indicate that electric systems which have favorable torque and
speed-control characteristics combined with high efficiency will have
initial costs (excluding the battery) comparable to or higher than the
                                                  L ,   182,183,185
present-day drive train or gasoline-powered automobiles.
Weight of the drive train depends greatly on the systems although
the order of magnitude appears to be about 1% to 2 kg/hp.  The VW
van being worked on at DAUG and VW suffers a weight penalty of about
100 to 200 Ibs for an electric vehicle without batteries compared to
a gasoline-engine-powered van.  Motor and switch gear possessing
optimal characteristics for electrics are not yet fully developed.
The drive train aspect of electric vehicles, however, does not appear
to present the limiting factor in the eventual realization of
efficiency and economically attractive electrical vehicles.
      d.  Hybrids -- Recent tests by EPA on a gasoline-engine-battery-
                               198
hybrid vehicle (Petro Electric)    demonstrated with a 43QQO Ifa vehicle
the following emissions and fuel economy over the Federal Driving
Cycle:
HC     CO     NO          MPG  (avg)   MPG (engine off at idle)
                x
(grams per mile)
0.45   2.08   0,90-1.14   10.4        12.4

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                                  206
A Wankel engine and lead-acid batteries were used.  The driveability
of this vehicle was acceptable.  Further improvements in meeting emis-
sions standards and in gas economy can be expected by using a conventional
small gasoline engine rather than the Wankel employed in this test vehicle,
                                     •j Q t "I fi7
Other test programs involving hybrids   '    have not produced as yet suf-
ficient data on emissions characteristics and on energy efficiency to
make meaningful conclusions possible.  Because hybrid drive systems are
more complex than either of the derivative systems, the initial cost of
the vehicle promises to be high.  However,  the anticipated longer cycle
life of advanced battery systems may provide a basis for favorable
vehicle cost per mile.
       Tests conducted at EPA in October-November of 1974  with the
Petro-Electric vehicle yielded the following results:
                       HC   0.38 g/mi
                       CO   2.41 g/mi
                       HOX  0.76 g/mi
                       MPG   9 urban
                            16 highway
These results were obtained at 4,000 Ib inertia weight and with a high
rear-end ratio.  The mileage is for the battery recharged to its
starting level.  A rotary engine is used in conjunction with the elec-
tric system.  Using an EPA determination factor for a rear-end ratio one
half that used in the test, and the improved economy of a piston engine
versus a rotary engine, the predicted urban mileage would be 1.35 x 2*  x
measured value =17.9 mpg.  Past EPA tests on the Petro-Electric vehicle
have indicated highway mileage nearly double the urban mileage.
       The electric system includes a set of starter, light, and ignition
(SLI) batteries having 90 amp hours of storage.  Discharge is only by
2 amp hours before recharging starts and does not normally exceed 6 amp
hours during operation.  Also included is an electric motor rated at
10 hp continuous, or 20 hp for one minute,  or 40 hp for acceleration.
   Telephone call from H. Wouk,  President^ Petro-Electric Motors, Ltd,
   to J. Bjerklie, December 12,  1974.

-------
                                  207
       Costs have been resolved except for the batteries and the motor In
large production.  Including these items, the purchase cost of Lhe Petro-
Electric vehicle would be between 1070-20% higher than the equivalent
gasoline-engine-powered vehicle for the same emissions and performance.
(Note;  This information was approved and added to the consultant report
December 13, 1974.)

       (e)  Power demand -- Most recent estimates on power demand   '  "  *
196 199
   3    to be created by electric vehicles tend to confirm earlier esti-
mates according to which the availability of centrally generated electri-
cal power and of distribution network is not likely to present a constraint
on the introduction of even a moderately large population (i.e., addition
of 1-2 million vehicles/year) of such vehicles.  Because of the load
leveling potential of electric vehicles (i.e., charging during off-peak
periods), economical benefits may be derived from such a power demand
                                                196
resulting in lowering the average cost of power.     In the planning of
central load leveling facilities, it would be of distinct advantage to be
able to rely on competent estimates regarding the expected penetration of
electric vehicles in the transportation system.

       (f)  Energy economy -- The energy requirement of an electrically
driven vehicle compared  to that of a gasoline-driven car has been
                             u j  180-184,188,195,196,199  „        _
estimated by a variety of methods.                         Because of
the paucity of road-test data on electrics, a fully reliable comparison
is still not available.  One of the key difficulties In making a valid
comparison between even  the smallest gasoline-driven automobile and an
electric vehicle available for road tests is that at present the only
battery system (i.e., the lead acid) at all suitable for vehicular
application provides extremely limited power and range.  Once we put
together on paper an electric car with performance similar to at least
the smallest cars on the road today (Honda, Pinto, Vega, VW, etc.),

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                                  208
we must anticipate performance of batteries which are not yet
available.
       Keeping the foregoing remarks in mind, recent system-performance
studies provide the following estimates:
       The energy requirements per mile of lead-acid-driven electrics
using current technology for the frame and driving train are comparable
                                    TOO 1QA
to the subcompacts on the road today   '     (0.25 to 0.5 kwhr/mile).
This disappointing performance results from the very high weight of the
battery required for even a marginal vehicle range and marginal accelera-
tion/hill-climbing capability.
       The energy requirements per mile for cars powered by "intermediate"-
type batteries (e.g., NiOOH, Ni-H7) can be expected to be comparable to
those of current subcompacts.  The higher energy density and power density
of these intermediate battery types will considerably reduce vehicle weight.
       The energy requirement of electrics using alkali metal-sulfur
batteries, with energy and power densities in the range of 100 kwh/lb and
100 wh/lb,, respectively, should be somewhat lower than present-day,
gasoline-driven vehicles (compacts) with comparable performance.
       It is worthwhile to compare the amount of raw fuel required
per mile to drive electric and heat-engine-powered vehicles.  From
the results indicated above, it can be assumed that electric cars com-
petitive to subcompact gasoline cars will  require an average of about
0.35 kwhr/mile.   On the other hand, a family-size car averaging 15 mi/
gal requires about 0.45 kwhr/mile.  This would correspond to an intermediate-
size car powered by a Stirling engine.  The conversion of raw fuel to
drive-shaft power would be approximately as follows:

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                                  209
                                          Electric Car      Heat Engine

Fuel processing efficiency            =       ,9               .9
Power plant efficiency                =      .32               .19
Trnasmission line efficiency          =      .91
Battery charge/discharge efficiency   =      .7
Motor/control efficiency              =      »8
Transmission and gear                 =      	              .9
Overall efficiency                    =      .146              .154
Adjusting for the difference in kwhr/mile required by the two modes
of transport, the ratio of electric vehicle to heat engine vehicle
fossil fuel requirements is 0,82.  This ratio is low enough to induce
some interest in electric vehicles at the present time.
        If the transportable fuel of the future requires more
thermal or electrical processing than indicated above, the energy
ratio will drop further since the fuel processing efficiency for
electrical generating plants need not change so long as fossil fuels
are used.  For instance, if hydrogen were to be required for
automobile fuel in the future, and if it were to be generated
electrolytically,  the ratio will be under 0,6.  This should include
higher interest in electric cars if energy remains a potential major
national problem.

-------
                            210
g,   Summary:
    (L)  There are no alternative engines that can be available
         in mass production for automobiles of standard size
         and performance before the 1980's.
    (2)  All  of the alternative heat engines can be made to
         meet the 1978 emissions standards} with Stirling
         engines and steam engines able to do so most easily
         and with least controversy on interpretation.
    (3)  Present gas turbines show poor fuel economy in urban
         driving, but could be made to show good characteristics
         for  touring-type driving.
    (4)  High-temperature gas turbines with ceramic components
         for  high-temperature portions of the engine should be
         technically competitive with spark-ignition engines
         over 50 hp and should demonstrate excellent fuel
         economy over a Federal Driving cycle.   Their economic
         competitiveness is not now clear.
    (5)  Stirling engines should ultimately be  technically
         competitive with spark-ignition engines over the
         power spectrum used by conventional automobiles.
         It is a necessary, but not sufficient,  condition to
         achieve a control system and heater head that can be
         made at a considerably lower cost than at present
         to be economically competitive.
    (6)  Steam engines  have been shown to be technically suitable
         as an exhaust-clean engine for powering lightweight
         cars.

-------
                        211
(7)   None of the alternative heat engines have been shown
     to be suitable in the hands of the public, although
     gas turbines come closet to having done so.
(8)   None of the alternative heat engines have been shown
     conclusively to have a suitable cost structure for use
     in conventional automobiles,
(9)   Light vehicles powered by efficient, externally heated
     engines (such as Stirling), using heat stored in a
     thermal storage system,, are being studied for their
     suitability as an urban vehicle.   The system has not
     yet been shown to be economically competitive.
(10)  Heat engine-battery hybrids have beem demonstrated
     successfully at the EPA to achieve on the Federal
     Driving Cycle; EC = 0.45 g/mi, CO = 2.08 g/mi and
     NO  = 0.9 to 1.14 g/mi, and to negotiate the Federal
       X
     Qriving Cycle successfully,
(11)  Flywheel systems have not been shown to be competitive
     with spark-ignition engines costwise, technically,
     or for overall emissions,
(12)  Based on present technology, it is feasible to
     manufacture electrically driven personal vehicles for
     restriced (low range and power) urban use.  These
     vehicles, even when equipped with the best,  currently
     available, lead-acid storage batteries, will have
     significantly higher initial cost and vehicle cost
     per mile than today's gasoline-driven subcompacts
     with no improvement in overall energy efficiency.

-------
                        212
(13) Active development programs exist for battery-powered
     delivery vans and urbans Susses. Their duty cycle
     offers an opportunity that is thought may prove
     economically viable for the introduction of electric
     drives and lead-acid batteries.
(14) By substantially increasing the cycle life of lead-acid
     batteries, major improvements in energy economy and
     vehicle cost per mile may be achieved by decreasing
     the cost per mile of the battery.  Significant
     improvement in range is not likely to be achieved
     with the lead-acid battery,
(15) Other battery types currently in advanced development
     stage (e.g., Zn-NiOOH,  H -NiOOH) may be expected
     within five years to provide approximately twice as
     high specific energy (range) and significantly improved
     power capability compared to the current best lead-acid
     system.
(16) The high energy and power density alkali metal-sulfur
     batteries currently under development show good promise
     and should reach advanced testing stage in two to
     three years.
(17) In view of the strong likelihood for a gradual shift
     toward coal-nuclear-geothermal and,  perhaps, solar
     primary  energy sources, there are incentives for the
     development of advanced storage batteries for
     electrically driven vehicles,
(18) A summary of fuel economy data for alternative engines
     is given in Figure 12.3.

-------
o
~z.
o
     30
     20
     10
                                  Ceramic Turbine
                                  (projected)
                                          - 2500  F
                                   51 Data-EPA
                                   Other—As Noted
                                           Emission Capability
                               •  Steam  \ ng7g Std; ,
                               D  Stirling {
                                            \  1978 Stds.-Variable
                               O  Gas Turbine  ^  2 g/mi N0^_.Fixed Combustion

                               A  Electric-Heat Engine Hybrid
                                  (1975 Stds.)
                                     Phillips (predicted!
                Iprojectedl
                                                              SES (predicted!
                       O
                    Williams Res.
                    lapprox.)
                                                                                   SEPA-1974 Spark Ignition
                                                                                   I Engines
      0
      2000
3000
      4000
VEHICLE WEIGHT (Ib)
5000
6000
FIGURE  12.3  Fuel  Economy  - Alternative Engines,   All Data Are Measured
Except:    Predicted from Dynamometer  and Projected from  Extrapolation,

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                     13.  ALTERNATIVE FUELS
13.1  Introduction
      The recent gasoline shortage in the United States has  served
to emphasize the critical dependence of our transportation system on
a readily available and abundant supply of gasoline.  Nearly all
present-day transportation systems are powered by petroleam-derived
fuels.  Petroleum currently supplies almost 507o of U.S. energy needs
•with the transportation sector, in turn, consuming about half the
petroleum.  Gasoline for automotive consumption represents
approximately 75% of this transportation fuel demand, or nearly 20%
of the total U.S. energy usage.  It is not surprising then that
alternative fuels for automobiles are of great current interest in
view of government plans to try to reduce the petroleum dependency
of the United States.
      The subject of alternative fuels interacts in various ways with
the current Committee on Motor Vehicles study.  First, and most
obvious, the types of fuels available can potentially have a
significant effect on the performance, efficiency and emissions
characteristics of the various automotive power sources being
considered.  Thus, an attempt is made here to identify the alternative
fuels that may become available in the future,
      The type of fuels which will be available will, in turn, depend
upon the future energy supply spectrum.  National policy concerning
this future energy mix is currently being formulated in terms of
research and development goals and budgets for nuclear. coal, oil shale
and other energy sources.  The identification of those synthetic fuels
which are most attractive for automotive applications should serve as
input to these energy policy decisions.  Those alternative fuels
particularly advantageous for automotive use are identified  and
discussed in the present study.
      Another motivation for considering alternative fuels is the
interaction between alternative fuels and alternative power  plants.

                                  214

-------
                                  215
Many of the alternative power plants are chacterized by continuous-
combustion systems with relatively little fuel sensitivity, while
other power plants may require fuels with specific octane or cetane
ratings.  The future availability of fuels of various types may then
affect decisions regarding production of automotive power plants
of a given design.  The spectrum of available fuels may also affect
the design of conventional spark-ignited engines, stratified-charge
engines and diesel engines, and discussion of alternative fuels
for these engines is included here.
      For the present study, alternative fuels are defined as those
fuels not derived from the normal petroleum base.  Fuels which are
derived from such sources as coal, oil shale, natural gas or nuclear
energy resources are considered.  Except for direct use of natural
gas, all of these energy sources require further synthesis or
conversion to obtain a form suitable for automotive application.
Hence, the term "synthetic fuel" can also be used to characterize
fuels from these resources.  In the cases where  the alternative fuels
are synthetic gasoline or synthetic distillates, the discussion
includes information on their potential availability and cost, but does
not dwell on their application to conventional vehicles.
      The objective of this study is to assess the potential for
alternative automotive fuels from the standpoint of energy supply
and cost, vehicle efficiency, performance and emissions.  Also,
where possible, an attempt is made to assess the time frame for
availability of the various synthetic fuels.
      A summary of synthetic fuel cost and supply data based on
presently available estimates is given in the next section.  Subsequent
sections contain detailed assessments of the prime non-conventional
synthetic fuel candidates:   hydrogen, methanol and gasoline-methanol
blends.   A discussion of systems employing reformed fuel is also
included because these systems have potential fuel economy and
emissions advantages.

-------
                                  216
 13.2  Candidates, Costs and Time Scales
      Given  the energy resource picture for  Che United  States
 and the  projections  for rates of energy usage, it quickly  becomes
 apparent that a heavy reliance on imported petroleum can only  be
 avoided  by exploitation of non-petroleum, domestic energy  resources.
 A  typical petroleum  demand projection is shown in Figure 13.1,  taken
 from Reference 200 and indicates that petroleum demand due  to
 transportation alone will outstrip domestic  supplies by 1980.
      It is  of interest then to consider the possibility of using
 non-petroleum energy resources for synthetic fuel production for
 automotive transportation needs.  The available major domestic
 energy resources in  this category include coal, oil shale  and
 nuclear  supplies.  Solar and geothermal energy resources may also
 enter the picture, but detailed analyses of  their application  to
 synthetic fuel production are not readily available.  Foreign
 natural  gas  is the other non-petroleum resource considered here.
 Given these  energy resources, fuel candidates, costs and availability
 are analyzed in this section.
      Recent studies performed for the Environmental Protection
                                                201 202
 Agency by the Institute of Gas Technology (1GT)    3    and Exxon
                        203
 Research and Engineering    have identified alternative automotive
 fuel candidates and costs based on use of domestic resources.  While
 both studies started with a long list of possible fuels, many were
 immediately eliminated for obvious hazard, availability, storability
 or cost  problems.  The IGT study provided cost data for a number
 of fuels, while the Exxon analysis eliminated all but a few
 candidates for practical reasons before final cost Bata was completed.
Cost estimates from these studies in 1973 dollars per million  Btu
 at the pump are shown in Tables 13.la and 13.Ib.   Current gasoline
 prices (without taxes) are equivalent to about $3.50/10  Btu.

-------
                             217
   10


    9
       Cumulative ot! consumption
       (109bbl)              108
                Approximate _
                total energy
         210
          |
Total demand f   \
   V     /,    / Electric utilities

     \^/  <
      ^,jK"-y   j
                                       /:%1
                                      ^^:;    N
                                      'v;XvX'x'i    > Industrial
                                       •-f~-' O- -. ••!   i
                               ransportation
                               (60 X 109 bbl)
                                                  Trinsportation
              1960        1§70

                       YEAR
  1980
1990
FIGURE 13.1   U.S.  Petroleuci  Supply  and Demand  (Including
Natural  Gas Liquids),
Source:   Reference  200

-------
                                218

                           TABLE 13, la


                    Cost of Alternative Fuels
                                                     Cost at Pump
Resource Base             Synthetic Fuel             $10/6 Btu. __
Coal                      Gasoline                   3.00 (+1,70)
                          Distillate                 2.65   *<+1«
                          Methanol                   2.85 (+2.38)
                          Liquid SNG                 3.60 (+0.94)
                          Liquid H2                  5.65
                          H2-Hydride                 3.55
*Co- product ion (50-50) gasoline and distillate
Oil Shale                 Gasoline                   2.95 (+1.20)
                          Distillate                 2.50 (+1.20)
Nuclear Energy            Electrolytic H
                            Liquid HZ                7,60
                            H -Hydride               5.50
                          Thermochemical H
                            Liquid H                 6.10
                            H -Hydride               4.00
A s s_umj3 I: ions :
      Costs are in late 1973 dollars, for investor financing with
approximately 10% DCF.  Capital and operating costs were based on
published (late 1960's) costs and are probably somewhat optimistic.
No te :
      IGT has recently completed more detailed cost analyses for
several of the above fuels.  These costs were based on full-size
plants reflecting maximum economy of scale.  Costs included total
plant investment, 1070 overhead, 157, contingency, interest during
construction, start-up costs and operating costs.  Substnatially
greater production costs were obtained in this analysis.  Increases
are shown in the figures in parenthesis above (Ref. 2a).
                                                     RBF  201

-------
                                 219

                            TABLE 13.Ib
                     Cost of Alternative Fuels
                                                     Cost at Pump
Resource Base             Synthetic Fuel             $/10  Btu
Coal                      Gasoline                        3.35

                          Distillate*                     2.75

                          Methanol                        3.85


Oil Shale                 Gasoline                        2.65

                          Distillate*                     2.05




^Produced as coproduct with gasoline




Assumptions:

   1973 Dollars, 10% DCF Return.
                                                     REF  203

-------
                                  220
           204
      Jaffe    e t a 1 . have estimated selling prices for methanol from
coal for a number of coal sources and gasification processes.  Their
results for methanol from coal, without coproduct, are in the range
$250-$3. 00/10  Btu for investor financing at 127, DCF.  Transportation
charges (about $1.50) would have to be added to these costs to arrive
at a cost.
      Other estimates for methanol costs are also available.  Vulcan-
Cincinnati Company estimates that methyl fuel (methanol with small
amounts of high alcohols) could be produced from coal for $1,02/10  Btu.
Dutkiewicz    estimates that methanol produced from natural gas in the
Middle East could be brought to the United States for $1.05/10  Btu.
                                                                  202 203
Transmission and distribution would add about $1.50 to these costs   *
for an estimated total delivered methanol cost of $2.50/10  Btu.
      The time frame for availability of the various synthetic fuels
is also of interest.  The Office of Coal Research (OCR) estimates that
the data necessary for design of a commerical-size plant for substitute
                                                                 207
natural gas (SNG) production from coal will be available by 1980.
However, due to increasing demand for natural gas in present markets,
it is unlikely that SNG from coal would be available for automotive use
                              202
any time before 2000, if then.      The state of the art in coal lique-
faction in the United States is not as advanced as coal gasification,
OCR estimates that the technology for pilot and demonstration plants for
                                                                   207
liquid fuels from coal should become available in the early 1980's.
Allowing time for demonstration plant operation, synthetic liquids
(gasoline and distillates) from coal will probably not be available in
substantial quantity before the late 1980's.
      Production of methanol or methane and methanol is another
possible option for coal gasification plants.  This would involve

-------
                                   221
 first producing synthesis gas (containing large quantities of CO and
 H ) in much the same way as in SNG production,  Methanol would then
 be produced from the synthesis gas by commercially available catalytic
 conversion methods.  This would have the advantage of producing a
 liquid fuel from coal while requiring only gasification technology
 rather than direct liquefaction technology.  An early 1980's time
 frame is then probably appropriate for methanol from coal.  Mills
            208
 and Harney    have discussed methanol production from coal and
 suggest a production cost in the range of $1.00-$1.20/10 Btu,  Methanol
 is currently produced via steam reforming of natural gas, and it has
 been suggested that natural gas from the Middle East be converted
                                               206
 to methanol for shipment to the United States.     No further
 technological development would be required here.
       Production of gasoline and distillates from oil shale is also
 an attractive low-cost option (Tables 13. la, 13.Ib).  Oil shale
 leases have recently been granted and processing plants are being
 designed.  The technology for retorting the shale oil to a synthetic
 crude oil is known, and a few plants based on ~urface mining of shale
                                                    209
 will probably be in operation in the early 1980's.     The major
 limitations here are not technology development or processing costs,
 but enviornmental problems and water shortages which may limit
 the scale of operation.
       Cost estimates for either liquid or metal hydride forms of
 hydrogen are relatively high (Tables 13.la, 13.Ib) due to inefficiencies
 in the electrolytic or thermochemical production methods and the
additional costs for either liquefaction or hydride formation.
 Electrolytic hydrogen production followed by liquefaction is a currently
 available technology,  and development of more efficient electrolyzers
 continues.   Thermochemical hydrogen production and metal hydride
 storage systems are still in the early stages of development and
 may not be commercially available until the late 1980's.  Although

-------
                                   222
production of gaseous hydrogen may be relatively  cheap  (Tables  13.la,
13.Ib),  its low density eliminates it as an automotive  fuel.
      Given the above cost and availability estimates,  we  identify
the most attractive alternative fuels as follows.   Some quantities
of  methanol from either coal gasification or foreign natural gas will
probably be available as early as 1980,  If system  studies  indicate
that  this fuel should be used in the transportation sector, then use
of  gasoline-methanol blends for automobiles would be an early
application.  Larger-scale production of methanol in the late 1980fs
could result in some use of methanol itself as an automotive fuel.
The most likely synthetic fuels for the late 19SO!s and the 1990 !s
appear to be synthetic gasoline and distillates from coal or oil
shale resources.  Hydrogen may appear as an automotive  fuel, but will
probably not be widely used before 2000.
      A more detailed discussion of the automotive  application  of
several synthetic fuels is included in the following subsections.  No
further discussion of synthetic gasoline or distillates is given since
these would be essentially the same as presently available fuels.
Systems which include on-board reformers are also discussed since,
even  though the vehicle may be fueled with conventional fuels,  the
engine will operate with some portion of synthesized fuel.

13.3  Hydrogen
      During the past few years, hydrogen has received  a great  deal
of attention as a potential energy carrier of the future.   Its  major
attractions include the absence of carbon in the fuel and the vast
availability of hydrogen in water.   The prime energy sources in
a  hydrogen-energy economy would be nuclear,  solar or geothermal,
and the hydrogen produced from these resources would serve the  need
for an easily transmitted, storable, portable energy carrier.    While
the beginning of any conversion to a hydrogen   economy appears to

-------
                                  223
be at least 25 years away, many  investigations of hydrogen's potential
as an automotive fuel have already been carried out.  The present
section discusses vehicular storage problems and potential automotive
engine performance and emissions with hydrogen as a  fuel,
      Assuming widespread production and distribution of hydrogen
as a multi-purpose energy carrier, the major problem accompanying
its use as a vehicular fuel is the requirement for on-board fuel
storage.  The low volumetric energy density of hydrogen eliminates
gaseous storage and leaves cryogenic liquid hydrogen or solid metal
hydride compounds as possible storage modes.  Cryogenic hydrogen
storage systems would occupy four to five  times the  volume of present
gasoline tanks, and would require a vacuum-jacketed, specially
                                           200 213
insulted tank to minimize boil-off losses.   *     At the present
time, such cryogenic storage systems would be quite  costly, although
large-scale mass production should reduce costs considerably.  All
of this supposes a method for liquid-hydrogen delivery to individual
vehicles.  Gaseous pipelines to  service stations with liquefaction
equipment or widespread distribution of liquid hydrogen would be
required.
      Metal hydride storage involves the formation of a solid phase
metal-hydrogen chemical compound, e.g., Mg H .   Although the weight
fraction of hydrogen in these compounds is usually less than 5%,
quite high hydrogen storage densities can be achieved by virtue
of the solid phase.   Magnesium or magnesium-nickel hydride systems
are estimated to weigh 600-700 Ib to give an energy  storage equivalent
                          ,  200,210
to a standard gasoline tank          Iron-titanium or magnesium-iron-
titanium hydrides have operating temperatures and hydrogen evolution
rates more suitable for vehicular application,  but would weigh as
                 211
much as 1,500 Ib.     The metal hydride decomposition to give the
hydrogen fuel is an endothermic chemical reaction,  and the vehicular
system would therefore require a provision for cold  start-up and

-------
                                  224
exhaust-heat recycle to deliver the fuel to the engine.  Some
demonstration hydride storage systems have been built and laboratory
research programs continue to investigate lighter-weight metal
                  017
hydride compounds.     Much of this research is being carried out
at Brookhaven National Laboratory.  Widespread use of metal hydride
storage would^ of course, require a metal readily available in large
quantities.  Hydrides can be recharged from a pressurized gaseous
hydrogen supply so that cryogenic distribution is not required.
      While the vehicular storage of hydrogen requires some research
and development before widespread practical application is possible,
the efficient use of hydrogen in the vehicle power plant can be
accomplished with present-day technology.  Hydrogen-air mixtures
are easily ignited and burn rapidly over a wide range of mixture
ratios.  Alternative engines which employ continuous combustion
systems (Brayton, Rankine or Stirling engines)  are thus readily
adaptable to hydrogen fuel.   The primary combustion zone in these
systems can be operated much leaner than with hydrocarbon fuels so
that low nitric oxide emissions are easily attained.
      Application of hydrogen to spark-ignited, reciprocating engines
requires some engine modifications for proper operation and some gain
in engine efficiency is possible.   We mention here some recent
experimental results on the performance, emissions and special
problems of hydrogen-fueled, spark-ignited,  reciprocating engines.
      Since hydrogen-air mixtures  require only  one tenth the ignition
energy of gasoline-air mixtures, preignition and flashback can be
problems when operating with hydrogen.  Both intake water injection
and exhaust gas recirculation (EGR) have been used to eliminate
these problems,"   '      Both of these techniques also reduce nitric
oxide emissions and maximum engine power, and water has the
additional complication of requiring a storage  tank which must be
                                            O t Q
freeze protected.   Direct cylinder induction    and high-pressure,

-------
                                  225
direct-cylinder fuel injection    '    have also been used  to eliminate
flashback and preignition problems.  Direct injection has  a
supercharging effect and can increase power output  20% over a
carbureted system.
      Engine knock is also a problem with hydrogen-fueled  reciprocating
engines due to the high flame speeds of hydrogen air mixtures.  To
avoid this, it has been found necessary to operate with mixtures much
leaner than stoichiometric or to employ EGR.         Both  of these
techniques result in some loss in maximum engine power,
      A notable advantage of operation with hydrogen is the efficiency
gain attained through quality regulation of the engine power compared
with controlling output by throttling.  This is possible because
of the extremely wide flammability  limits of hydrogen-air  mixtures
   , ,    ,      ,     _   .   .        ,    ,    ,,. .      214,219
and has been shown to give increased engine efficiency.
      Nitric oxide emissions with hydrogen fuel are affected by
engine variables in much the same way as with gasoline fuel.  While
                                              217  219
anomalously low emissions have been reported,    *    other
investigations have shown NO  emissions to be similar to operation
               214,215,220   x             n                J ,
with gasoline.                  NO  control can be achieved by water
                                  fi
injection or EGR as mentioned previously, and also by very lean
operation.  Extremely low NO  emissions can be obtained by restricting
                            X
equivalence ratios to one half or lessj although this then requires
                                                   214-220
a larger engine to achieve the same maximum power,
      In summary, hydrogen is an attractive fuel from an emissions
and economy viewpoint and can be used to fuel conventional-type
engines.   However, substantial development in vehicular storage
systems would be required for large-scale use of hydrogen.   Such
large-scale use may be required beyond the year 2000 as fossil fuel
supplies  are depleted.

-------
                                  226
13.4  Methanol
      Methyl alcohol (CH^OH), or methane!, has been identified as
a possible future synthetic fuel and has received considerable
attention recently.  The present subsection discusses automotive use
of methanol fuel with respect to -vehicle performance and emissions.
Again, the continuous-combustion alternative engines are relatively
insensitive to fuel type and are easily designed for operation on
methanol.  Thus, the discussion is mainly concerned with methanol-
fueled, spark-ignited reciprocating engines.
      The use of alcohols as motor fuels is not a new idea.  The
Society of Automotive Engineers held a special meeting on alochol
                  221           222
fuels 10 years ago    and Bolt's    survey presented at that meeting
refers to work dating back 50 years.  The present discussion is not
a comprehensive review of alcohol fuels but rather a brief
evaulation of the principal operational, performance and emissions
characteristics of methanol-fueled reciprocating engines.  Although
ethyl alcohol (ethanol) does not now appear to be a cost-effective
                 202
alternative fuel,    much of the present technical discussion is
applicable to ethanol as well as methanol.
      A comparison of the physical properties of methanol and
iso-octane is given in Table 13.2, taken from Reference 223.  The
energy content per cubic food of stoichiometric methanol-air mixture
is about the same as with gasoline so that the engine power will be
similar.
      One of the major problems associated with the' use of methanol
is fuel vaporization and distribution characteristics due to methanol's
relatively high heat of vaporization and large F/A ratios.  Experimental
work with methanol indicates that specially designed carburetors
and intake manifolds will be required to provide the necessary fuel
                             222-225
evaporation and distribution.          The high heat of vaporization
can, in principle, be advantageous in that it results in cooler

-------
                                  227

                            TABLE 13.2




          Physical Properties of Iso-octane and Methanol
Property

Chemical formula

Molecular weight

Specific gravity (68 F)

Stoichiometric A/F

Boiling temperature, F  (K)

Latent Heat of vaporation at
  B.P., Btu/lb (MJ/kg)

Heating value, Btu/lb (MJ/kg)
  Higher
  Lower

Energy, Btu/ft  of Stoichiometric
  mixture (1 atm, 60 F, LHV,
  gaseous fuel) (MJ/nr*}

  Same, liquid fuel

Octane No., Research

Octane No., Motor
Iso-octane


C8H18

114.22

  0.692

 15.1

211 (372)


117 (0.490)
20,556 (86.047)
19,065 (79.806)
 95.5 (3.559)

 96.6 (3.600)

100

100
 Methanol

 CH3OH

 32.02

  0.792

  6,4

 149 (338)


 502 (2.101)
 9770 (40.897)
 8644 (36.184)
 90.0 (3,354)

103.0 (3.839)

 106

 92
                                                      REF  223

-------
                             228
 intake manifolds  and better  volumetric  efficiencies  as  well as less
                                  rj rj £"
 compression work  in the  cylinder,  ""  The  high heat  of  vaporization
 also means that methanol-fueled vehicles cannoC  be started in
 environments below 50 F  without the  addition  of  a more  volatile fuel
          223-225
 compound.         The problem here  is vaporization rather  than
 distribution, as  indicated by tests where  manifold injection of
                                                        9 o/
 methanol did not  improve cold-starting  characteristics.      It is
 interesting to note that coal-derived methanol may contain small
                           225
 amounts of higher alcohols    which may help  alleviate  the cold-start
 problem,
      Performance, fuel  economy and emissions with niethanol have also
 ,         ^  .    «..  „ ,223,225,226,228,229          „ .,   .   ,
 been recently investigated        '    5                  Both single-
 cylinder-engine experiments  and tests with properly  carbureted  and
 manifolded-multieylinder engines indicate that the lean  misfire  limit
 for methanol occurs at about 20% leaner mixtures than with gasoline.
 Significant decreases in GO and HC emissions can be  obtained   by
 operating with these leaner mixtures.   Increased emissions  of
 aldehydes are generally  observed along  with some reduction in  nitric
 oxide emissions.  The principal hydrocarbon emission is methanol,
which will be removed with water if an  exhaust sample dryer is  used.
The methanol response on FID analyzers  has been found to be between
 8070 and 100% of saturated hydrocarbon response.  Performance and
 fuel economy (on  an energy basis) are generally found to be quite
similar to values obtained with gasoline.  Since methanol  has  about
half the heating  value of gasoline, methanol-fueled  vehicles would
require twice as  large fuel storage tanks  for the       range as
gasoline.   A 1970 vehicle converted to  methanol operation  and equipped
with a special intake manifold and an exhaust-oxidation catalyst has
met the 1976-77 Federal  Emissions Standards without  specific NO
                                <-s <-> *\                            X
                                2z3
control except lean carburetion.      This  vehicle did experience
severe cold-start problems until an ether  injection  system was installed.

-------
                                  229
      Corrosion of lead, magnesium or aluminum fuel tanks or  tank
coatings has been identified as a severe problem in methanol fuel
        226
systems.     Corrosion of fuel-injector or carburetor parts can also
be a problem.
      In summary, with respect  to reciprocating engines, we find
that methanol is a suitable automotive fuel for the future providing
that the cold-start and F/A distribution requirements are included
in the engine design.  This would require major redesign of existing
engine intake systems.  Corrosion-resistant materials would have to
be used in vehicle fuel tanks and lines including parts of the fuel
injector or carburetor.  Methanol appears to have the capability
for lower emissions (except for aldehydes) than gasoline, principally
due Lo the lower lean misfire limits,  Methanol can be burned in
continuous-combustion-type engines with little or no difficulty as
long as a suitable start-up system is available.

13.5  Methanol-Gasoline Blends
      Blends of gasoline with up to  251 methanol have been suggested
as gasoline "extenders'' for present-day vehicles and are currently
                                                                   230
receiving increased attention as a result of recent fuel shortages.
Like pure methanol, methanol-gasoline blends have long been known as
potential fuels3 particularly for power boost in racing applications
where fuel injection and very rich mixtures are used.  In this
subsection the fuel mixture and engine performance and emissions
characteristics of raethanol-gasoline blends are briefly reviewed
and assessed with respect to application to spark-ignited reciprocating
engines.  As with most other alternative fuels, little or no problems
would be encountered burning these blends in continuous-combustion
engines.
      Methanol added to gasoline has the effect of increasing the

-------
                                  230
 octane  number  of  the  fuel,  although  this  point has  been overemphasized.
 While the  research octane number  (RON)  of modern  gasolines  is  increased
 about four octane numbers (OH) by  addition of  10%  methanol,  the more
 severe  motor octane number  (MON)  rating is only increased about 2 ON.
 (226,231,232)     Road  octane numbers, which are measured in vehicle
 tests,  are found  to be between  the RON  and MON values,  and  10%
                                                             226
 methanol in unleaded gasoline gives  about a 3 ON  boost  here.
      Fuel, volatility  is also affected by mixing  methanol with
 gasoline.   Distillation  tests show a more rapid distillation at the
 lower temperatures for alcohol-gasoline blends compared with gasoline
      222,226,232      m, .           .    ,  .           ,   r   ,
 alone.                  This despression  of the front end of the
 distillation curve can affect vehicle starting characteristics and
                                                             235
 may allow  for  use of heavier components in the base gasoline.
 The Reid Vapor Pressure of methanol-gasoline blends is  higher  than
 either  methanol-or gasoline-vapor pressures, and  this may indicate
                                              *? 9 fi 9^0
 an increased tendency  for vapor-lock problems,
      Methanol-gasoline blends  are known  to be extremely sensitive
 to the  presence of small (—*0.1%) quantities of water.   The water can
 cause the  separation of the blend resulting in the settling of a
water-methanol mixture to the bottom of the storage container
 (222,225,226,232).     fhe presence of higher alcohols  can help
 alleviate  this phase separation, but quantities on the  order of
 several percent are required.  While some vehicle-test  programs  have
                                              233
not shown  any  problems with phase separation,     others  have
exhibited  engine stall attributed to methanol separation in the
carburetor bowl.      Large-scale use of methanol-gasoline blends
would require  special water-free bulk distribution, vehicle-storage
and carburetor-bowl facilities  to minimize moist  air intrusion.
      Attention has also been given to comparisons of engine
performance, fuel economy and emissions between vehicles fueled with
gasoline and those fueled with  gasoline-methanol  blends.  If the

-------
                                  231
vehicle carburetor is not adjusted, then  the addition of ntethanol to
the gasoline causes a leaner overall stoichiomeCry,  In this case
Federal-Test-Cycle evaluations with 10% methanol  indicate a 507»
reduction in CO, a 10% reduction  in NO  ,  very little change in
                                      x
unburned hydrocarbons, and a 107..  reduction in rniles-per-gallon fuel
        231                                               2"M
economy.     Other road tests also show the CO reduction,    but do
                                                                    234
not give consistent fuel economy  results.  Both slight improvements
                                                      9 *7 A
and slight losses in fuel economy have been reported.     While some
road programs do not report driveability  problems with methiinol
blends,    other groups (with substantial driveability evaluation
experience) report significant driveability degradation with methanol
       226,231
blends.         Since the addition of methanol without carburetor
adjustment does lean the mixture, ye. would expect lean misfire
driveability problems on Late-model engines which are already
adjusted close to the lean limit.  Addition of methanol and adjustment
of the carburetor to maintain stoichiometry would undoubtedly
compromise the above-mentioned CO emissions reduction.  Federal-Test-
Procedure data for methanol-gasoline blends is shown in Figure 13.2
and Table 13,3,
      Recent evidence indicates that vehicle fuel-tank and
distribution systems may experience severe corrosion problems with
                         226
methanol-gasoline blends.
      In summary, methanol-gasoline blends can be used in conventional-
type engines provided carburetors are adjusted to maintain driveability,
Some reduction in CO emissions may result, but other emissions and
fuel economy will not be significantly altered.  Careful attention must
be given to bulk fuel-distribution and storage systems and vehicle
fuel systems to avoid problems of phase separation and corrosion.

13,6  Reformed Fuels
      The addition of small amounts of hydrogen to normal fuel systems

-------
                                 232
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          m
FIGUKE 13.2  Emissions Data for Alcohol-Gasoline Blends,  1975  Federal
Test Procedures, 455 CID 1973 Engine with No Carburetion Adjustment.
Source:   Reference 234

-------
                                  233
                            TABLE 13.3
             Test Data for 15% Methanol-Gasoline Blend
                                      Exhaust Emissions, s/mi, Fed. Test Procedure
1967 Car   Gasoline .
           Gasoline + 15% methanol
1973 Car   Gasoline
           Gasoline + 15% methanol
"1975 Car" Gasoline
           Gasoline + 15% methanol
1977 Federal Standards
Gasoline, mpg
Gasoline + 15% methanol5 mpg

  % Change, rnpg
  % Change, railes/Btu
HC
5.2
3.8
1.1
1.1
0.10
0.10
0.4

1967
(Rich)
14.3
14.4
+1
+8
CO
83
41
21
8
0,3
0.4
3.4





NO
	 X
6.4
8.1
2.6
1,7
2.6
2,3
1.5
Car
1973
(Lean)
11.2
10,6
-6
+1
Formaldehyde
0.13
0.20
0.075
0.10
0.002
0.004


"1975"
Catalyst Equipped
11.4
10.9
-4
+3
Notes
1)

2)

3)
Engines - 1967 289 CID V-8} air-gasoline equivalence ratio 0.9
          1973 351 CID V-8, air-gasoline equivalence ratio 1.05
         "1975"351 CID V-8, air-gasoline equivalence ratio 1.0
Carburetion was adjusted for gasoline-air mixtures and not changed
for blends.
The "1975" car was equipped with a catalytic converter.
                                                             REF 206

-------
 (hydrogen-supplemented fuel) can extend the lean misfire  limit  for
 spark- ignited, reciprocating engines  to quite lean stoichiometry.   Such
 lean mixtures result in significant improvements in engine  thermal
 efficiencies and very low NO  and CO  emissions, but usually result
                            .X.
 in higher unburned hydrocarbon emissions.  One concept for obtaining
 the required hydrogen involves reforming a portion of the gasoline  to
 hydrogen and carbon monoxide by means of an on-board partial oxidation
 reforming unit.  It is also possible  to reform other fuels, such as
         235
 methanol,    to obtain the hydrogen required.  In this subsection
 we review recent work with such hydrogen- supplemented fuel systems.
      The effect of adding various amounts of hydrogen to single and
 mu 1 1 icy 1 inder gasoline-fueled engines has been investigated at
                                     220
 General Motors Research Laboratories.     Relatively small amounts of
 hydrogen give dramatic reductions in  the lean limit.  In a single-
 cylinder engine, a mixture of 5% H  and 957, iso-octane (by mass)
extends the lean limit from an equivalence ratio ($) of 0.9 to about
0.7j while 107,, FL lowers the limit to  = 0,5.  With enough hydrogen
added to run at an equivalence ratio of 0,55, NO  and CO emissions
                                                x
are negligible, and unburned hydrocarbons are about the same as 100%
iso-octane at ji = 1.  Under the same conditions, thermal efficiency
increases from 33% at i = 1 to 37% at i> = 0.55, while the power
output drops about 307,,
      Vehicle tests with hydrogen-supplemented fuel were also carried
    220
out.     In tests with constant hydrogen mass flow, emissions were
measured using the Federal Test Procedure (hot start), and the results
are shown in Table 13.4 below.   Also shown in Table 13.4 are emissions
obtained with a fuel-metering system which enabled the relative
amount of hydrogen in the fuel to be held constant.  The results
indicate that lean operation with hydrogen-supplemented fuel does
dramatically reduce CO and NO  emissions, but HC emissions are
                             x
relatively high.

-------
                                  235
                            TABLE 13,4

               Federal Test Procedure Emissions with
                   Hydrogen Supplemented Fuels,

               Emissions  (g/mi)
               Constant Hydrogen Mass Flow   Constant Hydrogen Fraction

NC>                     1.3                                0.39
  Jt
CO                     5.6                                3.3
HC                     2.6                                3.1
                                                               REF 220
      The initial hydrogen-supplemented fuel concept arose at Jet
                                                                  rj -Q £"
Propulsion Laboratory  (JPL) and a  large program is underway there.'"
Single and multicylinder engine tests with added hydrogen confirm  the
results noted above.  The current  reformer unit is a homogeneous,
partial-oxidation type, operating  without water feed at 81% efficiency.
Development of catalytic-type reformers is also underway.  The
catalytic reformers operate at much  lower temperatures than the
homogeneous type and do not have the soot formation tendency.  However,
they must be warm to function properly and require prevaporized fuel.
      Limited vehicle tests with reformer-type products added to the
gasoline have been carried out at  JPL.  While the emissions results
were impressive on these tests, it was difficult to determine how
much improvement was due to the supplemented fuel and how much was
attributable to improved fuel vaporization and distribution due to  the
use of a special atomizing carburetor.  Such carburetors are known  to
make leaner operation possible.
      The reformed fuel concept is an attractive way to achieve the
lean operation required for low emissions and good fuel economy.
Reformer development and cycle testing are required to fully
demonstrate the system.  After such  demonstration, this concept should

-------
                                  236
be carefully compared with other methods for achieving overall
lean operation.
13.7  ^hej^Jilter native Fuels
      This subsection reviews several additional alternative  fuels
which have been suggested for their low-emissions potential.  These
fuels are all blends or emulsions containing a conventional fuel
and/or alcohol and water.  In general, much less engine  test  data
is available for these compounds than for the previously discussed
fuels .
      Water and gasoline or distillate combinations in which  a
surfactant is added to emulisfy she water have been suggested as
engine fuels.  In distillate combustion such emulsions result in a
micro-explosion of the water droplets before combustion because the
vapor pressure of the water is greater than the distillate vapor
pressure.  This micro-explosion shoutd produce finer fuel sprays
                                      237
and may reduce NO  and soot emissions.     Gasoline's higher
                 X.
volatility prevents the micro-explosion phenomenon from occuring in
gasoline-water emulsions and any reduction in HO  would be due to
                                237              x
the cooling effect of the water.     Also, if the carburetor  is not
adjusted, metering the gasoline-water mixture instead of gasoline
results in leaner engine operation.
      Limited emissions data are available from the California Air
Resources Board  (ARE)  cycle tests with "Vareb-10 Fuel", a fuel made
up of 57% Indolene, 38% Vareb emulsifier and 5% water by weight,
Cold-start test results are given in Table 13.5, taken from
Reference 238.   CO and NO  emissions were reduced, but cold-start
                         x
hydrocarbons increased.  The hydrocarbon reactivity ratio also
increased with the water gasoline emulsion.

-------
     TABLE 13.5
Effect of Vareb-10 on
Cold-Start Emission
Baseline
Test
Ho.
10
12
14
Avg.
1970 Chevrolet E 815472

HC
3.50
3.35
3.05
3.30

CO
39.08
36,00
24.48
33.19
Emissions
NOx
4.65
4.78
5.43
4.95
g/mt
CC-2
626
635
677
646

Aid.
0.091
0.076
0.067
0.078
React.
Ratio
0.471
0.448
0.474
0.464
Fuel Cons,
Weighted
1715
1748
1739
1734
g
Cal (1)
1649
1658
1710
1672
Vareb 10
Test
Ho.
11
13
ISA
Avg.
(1)
(2)

HC
3.53
3.79
3.48
3.60
Calculated
Multiplied

CO
9.83
9.84
9.11
9,59
from
by 0.
Emissions
NOx
2.14
2.26
2.08
2.16
_g/mi
CO?
651
657
695
668
emissions by carbon
836 to correct for

Aid.
0.063
0.105
0.092
0.087
balance.
14.4% HO.
React,
Ratio
0.582
0.569
0.583
0.578

Fuel Cons.
Weighed (2)
1684
1884
1827
1798

g
Cal (1)
1600
1616
1702
1639

                                       REF 238

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                                  238
      Homogeneous  blends  of  gasoline,  isoprepyl  or  tertiary butyl
 alcohol,  and water have been patented  by  Freeh and  Tazuma of Goodyear
                      239
 Research  Laboratories,     The  blends  contain about 40% alcohol,
 and water is added to  the miscible  range.   It is  proposed that these
 large quantities of  alcohol  would be obtained by  removing propene
 and  isobutene  from, current refinery streams and  converting them to
 isopropyl alcohol  or t-butyl alcohol.  Only very  limited vehicle-test
 data  is available  for  these  blends,  California cycle  tests on a  1969
 Dodge indicated reductions of 701-80%  in  CO, 30%-45% in H/C,  and
 25%-30% in NO  .  Fuel  economy was not  measured.   Increases  of about
 3 RON per 107,  alcohol  are claimed for  the blends.   More vehicle-
 test data and  an analysis of the refining costs are  necessary for  a
 full evaluation of the potential for these  blends.   In particular,
 tests on  late-model vehicles  are not expected to  show  as  large
 an emissions reduction as noted above,
      A water/methanol gasoline blend, in which a surfacant is
 used to obtain a stable emulsion of the water/alcohol  in  the  gasoline,
                                                240
 has been  suggested as  a emissions reducing  fuel.     Tests  using  a
 7.5% methanol, TL  surfacant, 0.5% water,  90% gasoline  fueled  1973
 vehicle (360 CID, A/F = 15.5:1, CR = 8,5:1) quite similar  to  previously
 discussed methanol-gasoline blends.  The  leaning effect reduced CO
 substantially but HC} NO  and fuel economy were not  significantly
                        ^C
 changed.   The use of a surfactant to increase the water  tolerance
 of methanol-gasoline blends  is noteworthy.  If such  a  compound were
 economically available in large quantities, it might help  solve the
water sensitivity problem and make the use  of gasoline-methanol
mixtures  more attractive.

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                                  REFERENCES
 1.  Furlong, L.E., E.L. Holt, and L.S. Burnstein, "Emission control
     and fuel economy," a paper presented at the American Chemical
     Society National Meeting in Los Angeles, April 1974.

 2.  "A Report on Automotive Fuel Economy/' EPA, October 1973.

 3.  LaPointe, Clayton, "Factors affecting vehicle fuel economy," SAE
     Paper No. 73091, September 1973.

 4.  Fegraus, C.E., C.J. Domke, and J. Marzen, "Contribution of the
     vehicle population to atmospheric pollution," SAE Paper No.
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 5.  Gumbleton, Bolton and Lang, "Optimizing engine parameters with
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 6.  Data obtained at meeting between NAS Technology Panel and General
     Motors Corp., May 1974.

 7.  EPA data.

 8.  The Federal Register, Vol. XXXVII, No. 221, November 15, 1972.

 9.  Meeting at General Motors Corp. with NAS Technology Panel,
     Augus t 1, 1974.

10.  Petersen, Robert A. (American Motors Corp.) in letter to Emerson W.
     Pugh (Executive Director, Committee on Motor Vehicle Emissions, HAS)
     August 2, 1974.

11.  Bowditch, Fred (General Motors Corp.) in letter to Robert F.  Sawyer
     (Consultant to the Committee on Motor Vehicle Emissions, NAS),
     August 5; 1974.

12.  W. Weber Master Catalog, Bologna, Italy.

13.  Rochester Product Division, General Motors Corp., Catalog pp 10-11.

14.  Private communications to CMVE consultants during visit to Wolfs-
     burg, Germany, June 19, 1974.

15.  "Modernizing the Fixed Venturi Carburetor," Automotive Engineering,
     July 1974, p 46.

16.  Larew, Walter, Carburetors and Carburetion, Chilton Publications,
     p 136.
                                    239

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                                 240
17.   Data presented to the Panel of Consultants on Engine Systems by
     Holley Carburetor,  May 14, 1974,

18.   British Patent, 1223921,  March 1971.

19.   D.A. Trayser.

20.   Dresser Industries, Inc., Environmental Technology Division letter
     to Robert F. Sawyer (CMVE consultant), February 27, 1974; and
     presentation by Ford Motor Co., Engine Research Office, Hay 16,
     1974 (Figures  9 & 10).

21.   Test of "Dresserator" Emission Control System, California Air
     Resources Board, Project 235, May 1973.

22.   Data presented to the Panel of Consultants on Engine Systems by
     Ford Motor Co., May 16, 1974 (Figures 3 & 4),

23.   Data presented to the Panel of Consultants on Engine Systems by
     Ethyl Corporation,  May 8, 1974.

24.   John, James E.A. (CMVE consultant) Trip Report on visit to Shell
     (Thornton) Research Ltd., Chester, England, June 145 1974.

25.   Visit to British Leyland UK Ltd., Coventry, England by CMVE
     consultants, June 18, 1974,

26,   "Ultrasonic Fuel Systems,1' Popular Science, March 1973, p 89.
     (Also, "Autotronics System," Hot Rod, January 1974.

27.   Electrojector - Bendix Electronics, SAE Transactions, LXV, 1975,
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28.   "Eine Electronische Gesteurte Kraftstoff Spritzung Fuer Ottomotoren,
     MT2, XXVIII (1967)  11, p 475.

29.   Communication to HAS consultants during visit to Volkswagenwerk AG,
     June 19, 1974 and Robert Bosch GMBH,  June 21, 1974.

30.   Statement by Daimler-Benz, Stuttgart, Germany to CMVE consultants
     during visit,  June  20, 1974.

31.   Statement by Saab-Scania Aktiebolag during Presentations of
     Foreign Manufacturers, May 21-24, 1974, NAS, Washington, DC.

32.   "Elecktronsche Benzin Einspritzung ntit Steuerung durch Lufttnenge
     und Motordrehzahl," MTZ, XXXIV (1974), 4, p. 99.

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                                241
33.  Statement by Volkeswagenwerk AG during Presentations of Foreign
     Manufacturers, May 21-24, 1974, HAS,  Washington, DC.

34.  Visit to Bendix Corp EFI Division by CMVE consultants May 7,
     1974 (Emissions Technology, p 21).

35.  Statement by Volkeswagenwerk AG during Presentations of Foreign
     Manufacturers, May 21-24, 1974, NAS,  Washington, DC, pp 4.2, 4.9
     and 8.2.  (Also, see CMVE consultant E. Jost's summary of VW
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36.  Bosch Continuous Injection System, (15) Robert Bosch GMBH Publica-
     tion, February 1, 1973.

37.  "Bosch Develops Continuous Fuel Injection," Automotive Fngineering,
     August 1973.

38.  Statement by AB Volvo during Presentations of Foreign Manufacturers,
     May 21-24, 1974, NAS, Washington, DC; also, p 32 of Volvo submis-
     s ion.

39,  Statement by Saab-Scania Aktiebolag during Presentations of Foreign
     Manufactuers, May 21-24, 1974, NAS, Washington, DC.

40.  "Closed-Loop Exhaust Emission Control System with EFI," SAE
     Meeting May 14-18, 1973, Paper No. 730566.

41.  Statement by Robert Bosch GMBH, Stuttgart, Germany during visit of
     CMVE consultants, June 21, 1974.

42.  Schweitzer, P.H., U.S. Patent 3,142,967, August 4, 1964; and
     'ftdaptative Control for Prime Movers," ASME Paper, November 1967-

43.  Visit to Ethyl Corp. by CMVE consultants, May 8, 1974.

44.  Visit to Shell Research Ltd. by J.EUA. John, June 14, 1974,

45.  Visit to Dresser Industries by CMVE consultants,  April 1974.

46.  Berriman, Lester (Dresser Industries) in letter to Robert F.
     Sawyer  (Consultant to Committee on Motor Vehicle Emissions),
     May 10,  1974.

47.  Austin,  T. (Environmental Protection Agency) in letter to J.E.A.
     John (Consultant to Committee on Motor Vehicle Emissions),
     August 7, 1974.

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                               242
48.  Visit to Ford Motor Co. by OWE consultants, May 1974.

49.  CMVE Technology Panel meeting with Ford Motor Co., Dearborn, MI,
     May 1974.

50.  CMVE Technology Panel meeting with General Motors Corp., Techni-
     cal Center, Warren, MI, Hay 1974.

51.  Presentation by British Leyland UK Ltd, during Presentations of
     Foreign Manufacturers, May 21-24, 1974, NAS, Washington, DC.

52.  Presentation by Nissan Motor Co, , Ltd. during Presentations of
     Foreign Manufacturers, May 21-24, 1974, MAS, Washington, DC.

53,  Presentation by Toyota Motor Co. during Presentations of
     Foreign Manufacturers, May 21-24, 1974, NAS, Washington, DC.

54,  Visit to Gould, Inc., Cleveland, OH by J.E.A. John, CMVE consultant,
     July 9, 1974.

55.  Austin, T. (Environmental Protection Agency) in letter to J.E.A.
     John (Consultant to Cottmittee on Motor Vehicle Emissions),
     August 7, 1974.

56.  Visit to Questor Corp., Toledo, OH by J.E.A. John, CMVE Consultant,
     June 6, 1974.

57-  Visit to General Motors, Warren, MI by CMVE Technology Panel,
     May 1974.

58,  Presentation of Foreign Manufacturers, May 21-24, 1974 3 NAS,
     Washington, DC,

59.  John,  J.E.A,, Trip Report of visit to Robert Bosch GMBH,
     Stuttgart, Germany, June 21, 1974.

60.  Visit to Ford Motor Co., Dearborn, Ml, by CMVE Technology Panel,
     May 1974,

61,  "EPA;  1974 Model Year test Results," The Federal Register,  Vol.
     XXXIX,  No. 40, Part 2, February 27, 1974.

62.  Meeting with Foreign Manufacturers, May 21-24, 1974,  NAS, Washington,
     DC.

63.  Wulfhorst, D., Trip Report o£ visit to General Motors Corp., Warren,
     MI,  June 21,  1974.

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                               243
64.  Wulfhorst, D., Trip Report of visit Co Toyo Kogyo Co., Ltd.,
     May 1974.

65.  Ricardo, H.R., "Recent Research Work on Che Internal Combustion
     Engine," SAE Journal, Vol. X, p. 305-336 (1922).

66,  Bishop, I.I. and A. Siniko, Society of Automotive Engineers
     Paper No. 680041 (1968).

67.  Simko, A., M.A. Choma and L.L. Repco, Society of Automotive
     Engineers Paper No. 720052 (1972).

68.  Mitchell, E., J.M. Cobb and R.A, Frost, Society of Automotive
     Engineers Paper No. 680042 (1968).

69.  Mitchell, E. , M. Alperstein and J.M. Cobb, Society of Automotive
     Engineers Paper No. 720051 (1972),

70.  "1975-77 Emission Control Program Status Report," Submitted to
     EPA by Ford Motor Co., November 26, 1973.

71.  Presentation by  Ford Motor Co. to CMVE Technology Panel, May 16,
     1974.

72.  Austin, T.C, and K.H. Bellman, Society of Automotive Engineers
     Paper Ho. 730790 (1973).

73,  Presentation by Texaco, Inc. to CMVE Technology Panel, March 28, 1974.

74,  Alperstein, M., G.H. Schafer and F.J.  Villforth III, SAE Paper
     Ho. 740563 (1974).

75,  Broderson, Neil 0., "Method of Operating Internal Combustion Engines,"
     U.S. Patent No. 2,615,437 and No. 2,690,741, Rochester, New York.

76.  Conta, L.D. and Pandeli, American Society of Mechanical Engineers
     Paper No. 59-SA-25 (1959).

77,	, American Society of Mechanical Engineers
     Paper No. 60-WA-314 (I960).

78.  Heintz, R.M., U.S. Patent No. 2,884,913, "Internal Combustion Engine."

79.  Nilov, N.A., Automobilnaya Promyshlennost No. 8 (1958)»

80.  Kerirnov, N,A= and R.I. Metehtiev, Automobilnoya Promyshlennost
     No, 1, PP 8-11 (1967).

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                               244
81.   Varshaoski,  I.L,,  B.F,  Konev and V.B.  Klatskin, Automobilnaya
     Promyshlennost No,  4 (1970).

82.   "An  Evaluation of  Three Honda Compound Vortex Controlled Combus-
     tion (CVCC)  Powered Vehicles," Report  B-ll, Environmental Protec-
     tion Agency, Test  and Evaluation Branch, December 1972,

S3.   "Automotive  Spark  Ignition Engine Emission Control Systems Panel
     To Meet Requirements of the 1970 Clean Air Amendments," Com-
     mittee on Motor Vehicle Emissions, NAS, May 1973.

84.   "An Evaluation of  a 300-CID Compound Vortex Controlled Combustion
     (CVCC) Powered Chevrolet Impala," Report 74-13, DWP, Environmental
     Protection Agency,  Test and Evaluation Branch, October 1973.

85.   General Motors Corp., Warren, MI  Environmental Activities Staff,
     Material submitted  to the CMVE Technology Panel following presen-
     tation on May 15,  1974.

86.   Presentation by Honda Motor Co., Ltd,  during Presentations of
     Foreign Manufacturers,  May 21-24, 1974, NAS, Washington, DC.

87.   Nissan Motor Co.,  Ltd., Report submitted to members of the CMVE
     Technology Panel,  June 20, 1974.

88.   Hewhall, H.K., and  I.A. El-Messiri, Combustion and Flame, XIV,
     pp 155-158  (1970).

89.   	, Society of Automotive Engineers
     Paper No. 700491 (1970).

90.   El-Messiri,  I.A. and U.K. Newhall, Proceedings of the Intersociety
     Energy Conversion  Engineering Conference, p 63 (1971).

91.   Ford Motor Co, Presentation to CMVE Technology Panel, January 24, 1974

92.   Decker, G. and W.  Brandstetter,  MTZ; MotorEechnische Zeitschrjft,
     Vol XXXIV, Ho. 10,  pp 317-322 (1973).

93.   John, J.E.A., Trip  Report on visit to   Volkswagenwerk AG, Wolfsburg,
     Germany, June 19,  1974.

94.   Report by Environmental Protection Agency, Ann Arbor, MI, January 23,
     1974.

95.   Springer, Karl J.,  "An Investigation of Diesel Powered Vehicle
     Emissions,"  Interim Report by Southwest Research Institute to
     the Environmental  Protection Agency, Contract PH 22-68-23, June 1974.

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                                245
 96.  Campau, R.M.,  "Low emission concept vehicle," SAE Paper No. 710294,
      1971.

 97.  Meguerian, G.H. and C.R. Lang, "NOX reduction catalysts for vehicle
      emission control, " SAE Paper No. 710291, 1971.

 98.  Patterson, D.J. and N.A. Henein,  Emissions from tombustion Engines
      and Their Control (Ann Arbor Science Publishers, Inc., MI, 1972).

 99.  Hearings, Subcommittee on Air and Water Pollution, Committee on
      Public Works,  United States Senate, 93rd Congress, 1st Session,
      May 14, 17, 18, and 21, 1973, Serial Ho. 93-H9.

100.  General Motors Corp. presentation to CMVE consultants, February 14,
      1974.

101.  Perkins Engines presentation to CMVE consultants, June 1974.

102.  Robert Bosch Corp. presentation to CMVE consultants, June 1974.

103.  Monaghan, M.L., C.C.J. French and R.G. Freese, "A Study of the
      Diesel as a Light Duty Power Plant," Ricardo and Co. Engineers
      Report to the Environmental Protection Agency, Report No. EPA-
      460/3-74-011,  July 1974.

104.  Dow Chemical U.S.A., seventeen reports on vehicle tests from
      Dow particulate testing for the Environmental Protection Agency,
      July 16, 1973-April 23, 1974.

105.  Cental, James E., Otto J. Manary and Joseph C. Valenta, "Charac-
      terization of Particulates and Other Non-Regulated Emissions from
      Mobile Sources and  the Effects of Exhaust Emissions Control Devices
      on These Emissions," Dow Chemical U.S.A. Publication No. APTD-1567,
      March 1973.

106.  Caplan, John D.,  "Smog Chemistry Points the Way to Rational
      Vehicle Emission  Control, " SAE PT-12, XX, 1963-1966.

107.  Altshuller, A.P,  "An Evaluation of Techniques  for the Determina-
      tion of the Photochemical Reactivity of Organic Emissions,"
      J. APCA, XVI,  No. 5, 1966, p 257.

108.  Henein, N.A.  (CMVE Consultant) in letter to J. McFadden, EPA-
      Ann Arbor, July 2, 1974.

109.  Presentation by Peugeot, Inc. during Presentations of Foreign
      Manufacturers, May 21-24, 1974, NAS, Washington, DC.

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                                 246
 110.   Ford  Motor Co.  presentation to  CMVE  consultants, May 1974.

 111.   Pichford,  J.H. ,  "The  development  of  a  small  automotive  diesel  in
       western Europe  and  its  likely role in  the  USA," SAE  Paper No.  215B.

 112.   Neild,  G.C.,  "Delivering  the mail with diesel--the Post Office
       Department looks  at diesel  engines," SAE Paper No. 65071.

 113.   Pichford,  J.H.,  et  al., "What problems  still restrain the small
       automotive diesel engine?",  presentation at  FISITA Conference, 1964.

 114.   Daimler-Benz  presentation to CMVE consultants, June  1974.

 115.   Perga,  M.W and  T.V. DePalma, "Diesel Engine  Pollutants-Control,"
       Hearings,  Subcommittee  on Air and Water Pollution, Committee on
       Public  Works, U.S.  Senate,  93rd Congress,  1st Session,  May  14,
       17, 18,  and 21,  1973, Serial No.  93-H9, p  956.

 116.   An Evaluation of  Alternative Power Sources for Low Emission
       Automobile^,  Report of  the  Panel on  Alternate Power  Sources to
       the Committee on  Motor  Vehicle Emissions, National Academy  of
       Sciences,  April  1973.

 117.   Brogan,  John  J.,  "Alternative Powerplants," Advanced Automotive
       Power Systems Development Division,  U.S. Environmental  Protection
       Agency,  IECEC,  1973.

 118.   	"The  automobile truck  sector of transportation,"
       Public  Address, May 1974.

 119.   Eltinge, Lamont,  "1970's  Development of 21st Century Mobile-
       Dispersed  Power,  A  Challenge Requiring  Nex
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                                 247
124.  Rogo, Casimir and Richard L. Trauth, 'Design of high heat release
      Slinger combustor with rapid acceleration requirement,"  SAE
      Automotive Engineering Congress, Detroit, MI, February 1974.

125.  Zwick, E.B., and R.D. Bottos, "Development of Low Emission Combus-
      tion System for the MERBC 10KW Turbo-Alternator,1T Zwick Co., May 1974,

126,  Zwick Co., Santa Ana, CA, 4/11/74.

127.  Solar, San Diego, CA, 4/10/74.

128.  Jet Propulsion Laboratory, Altadena, CA, 4/9/74.

129.  Ford Motor Co., Dearborn, MI, 2/13/74 -- gas turbines, Stirling
      engines.

130,  Chrysler Corp., Detroit, MI, 2/12/74 -- gas turbines.

131.  Williams Research, Detroit, MI, 3/27/74 -- gas turbines.

132.  Walzer, P., R.  Buchheim, P. Rottenkolber, G. liagemann, "Pas-
      senger Car Performance with the Experimental Gas  Turbine VW—GT 70,"
      ASME Publication 74-GT108.

133.  Buchheim, Rolf, "Das Emissionsverhalten der Personenwagen-
      Gasturbine VW-GT 70," Wolfsburg, MTZ Motortechnische Zeitschrift
      35, 1974.

134.  Walzer, Peter, Paul Rottenkolber, Gunter Hagemann, "Die Personnen-
      wagen-Versuchsgasturbine VW-GT 70," Wolfsburg, Sonderdruck aus
      MTZ Motortechnische Zeitschrift 34.  Jahrgang, Franckh'sche
      Verlagshandlung Stuttgart, Rummer 9/19/73.

135.  Klarhoefer, C, "Optimization of the Idling and Acceleration
      Characteristics of a Vehicular Gas Turbine by Analog Simulation,"
      ASME Publication 74-GT-103.

136.  Forschunasbericht, Nr. F3-73/18, Research Work at Volkswagen on
      Gas Turbines.

137.  Sheridan, David C., Gary E. Nordenson, and Charles A.  Amann,
      "Variable compressor geometry in the single-shaft automotive
      Turbine Engine," SAE Automotive Engineering Congress,  Detroit, MI,
      February 1974.

138.  Sanders, William A. and Hubert B. Probst, "Behavior of ceramics
      at 1200° C In a simulated gas turbine enviornment," Ibid.

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                                 248
139.   Beck,  Robert J. ,  "Evaluation of ceramics for small gas turbine
      engines," Ibid.

140.   Torti, M.L. , "Ceramics  for gas turbines, present and future,"
      Ibid.

141.   Bratton,  R.J., A.A.  Holden and S.E.  Mumford, "Testing ceramic staitor
      vanes  for industrial gas turbines,"  Ibid.

142.   Noda,  Furniyoshi,  "Aluminum nitride and silicon nitride for high
      temperature gas  turbine  engines," Ibid.

143.   Wolkswagenwerk AG,  Wolfsburg,  W. Germany, 5/24/74 -- gas turbines.

144.   Environmental Protection Agency, Ann Arbor,  MI, 1/22-23/74.

145.   Brobeck Associates,  Berkeley,  CA, 4/8/74 --  steam engine.

146.   Steam Power Systems, San Diego, CA,  4/10/74  -- steam engine.

147.   Jay Carter Enterprises, Burkburnett, TX, 4/12/74 — steam engine.

148.   Scientific Energy Systems, Watertown, MA, 3/8/74 — steam engine.

149.   Termo-Electron  Corp., Waltham, MA, 3/8/74 -- organic Rankine cycle.

150.   Teagan, W.P., and W. Clay. "3 KW Closed Rankine-Cycle Powerplant
      with a Turbine  Expander," Final Report, prepared for US Army
      Mobility Research and Development Center, Electromechanical
      Division, Ft. Belvoir,  VA, Contract  No. DAAK 02-72-C-0554,
      Section E, Item  #0002,  Exhibit A, Item A005, Thermo-Electron
      Corp., Waltham,  MA,  September 1973.

151.   Hodgson,  J.N.,  and F.N. Collamore, "Turbine  Rankine cycle auto-
      motive engine development," SAE Automotive Engineering Congress,
      Detroit,  MI, February 1974.

152.   Hoagland, L.C.  (Scientific Energy Systems Corp., Watertown, MA)
      in letter to J.W.  Bjerklie (CMVE consultant), March 19, 1974.

153.   Hoagland, L.C,,  R.L. Dernier, and J.  Gerstmann, "Design features
      and initial performance data on an automotive steam engine. Part I -
      overall powerplant description and performance," SAE Automotive
      Engineering Congress, Detroit, MI, February 1974.

154.   Syniuta,  W.D. and R.M.  Palmer, "Design features and initial per-
      formance data on an automotive steam engine. Part II - reciproca-
      ting steam expander - design features and performance, Ibid.

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                                 249
155.  Patel, P., E.F. Doyle, R.J. Raymond, and R. Sakhuja5 "Automotive
      organic Rankine-cycle powerplant - design and performance data,
      Ibid.

156.  Dutcher, Cornelius G,, Remarks before the Subcommittee on Space
      Science and Applications of the Committee on Science and Astro-
      nautics of the U.S. House of Representatives} February 6, 1974.
      (Mr. Dutcher is with Steam Power Systems, San Diego, CA,)

157.  Carter, Jay (Jay Carter Research and Development Engineers,
      Burkburnett, TX) in letter to J.W. Bjerklie, May 19, 1974.

158.  Minto, Wallace L.  (President, Kinetics Corp., Sarasota, FL) ill
      letter to J.W. Bjerklie, March 15, 1974.

159.  Keller, Leonard J. (President, The Keller Corp., Dallas, TX) in
      Letter to J.W. Bjerklie, March 22, 1974.

160.  The Keller Corp. Memorandum, "External Combustion Engine Systems -
      Recent developments and comments on state of the art," November 22,
      1971.

161.  Nichols, W.P-  (President, Paxve, Inc., Costa Mesa, CA) in letter
      to Emerson W. Pugh, Executive Director, CMVE), April 3, 1974.

162,  Younger, Francis C., "Characteristics of the Brobeck steam bus
      engine," SAE National West Coast Meeting, San Francisco, CA,
      August 21, 1972.

163,  Richardson, R.W.,  "Automotive Engines for the 1980's, Eaton's
      Worldwide Analysis of Future Automotive Power Plants, Eaton Corp.,
      Southfield, MI, July 1973.

164.  	__s  Statement to the Subcommittee on Space Science
      and Applications of the Committee on Science and Astronautics, U.S.
      House of Representatives, June 13, 1974.

165.  Philips Research Labs, Eindhoven,, Holland, 5/20/74 -- Stirling engines,

166.  United Stirling, Malmo, Sweden, 5/21/74 -- Stirling engines.

167.  MAH-MWM, Augsburg, W. Germany. 5/22/74 -•- Stirling engines.

168.  Kinergetics, Tarzana, CA, 4/11/74 -- Stirling engine.

169.  Postroa, Norman D. , Rob Van Giessel and Frits Reinink, "The Stirling
      engine for passenger car application," SAE Combined Commercial Vehicle
      Engineering & Operations and Powerplant Meetings, Chicago, IL, June 1973

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                                 250
170,  Carlqvist, S.G, and L.G.H. Qrtegren, "The potential impact of  the
      Stirling engine on environmental issues," prepared for presenta-
      tion to The Institute of Road Transport Engineers, January 1974.

171.  van Beukering, H.C.J, and H. Fokker, "Present state-of-the-art
      of the Philips Stirling engine," SAE Combined Commercial Vehicle
      Engineering & Operations and Powerplant Meetings, Chicago, IL,
      June 1973,

172,  Aim, C.B.S., S.G. Carlqvist, P.P. Kuhlmatm, K.H. Silverqvist,
      and F.A. Zacharias, "Environmental characteristics of Stirling
      engines and their present state of development in Germany and
      Sweden," 10th International Congress on Combustion Engines, Paper
      No. 18, 1973,

173,  Kuhlmann, Peter, Das Kennfe_ld_ des Stirlingmotors, Augsburg, M.A.N.
      Sonderdruck aus MTZ Hotortechnische Zeitsehrift, 34. Jahrg.,
      Nr. 5/1173.

174,  Asselinan, G.A.A. , J. Mulder, and R.J. Meijer,  "A High-Performance
      Radiator," Philips Research Labs.,  Eindhoven (The Netherlands),
      1972.

175,  "Hydorgen Safety of the Stirling Engine," Stanford Research Insti-
      tute, Menlo Park, CA, January 4, 1974.

176.  Stein, Robert A., "Progress Report on the Development of the
      Valved Hot-Gas Engine," M. Thesis,  ME Dept., MIT, January 1974.

177.  MIT, Boston, MA, 3/8/74 — reciprocating Brayton engine.

178.  Brobeck Associates, Berkeley, CA, Op. Git.

179.  Post, Richard F. and Stephen F,, "Flywheels," Scientific American,
      CCXX1K,  No. 6, December 1973, p. 17."

180.  Friedmanj Donald and Jerar Andon, "The Characterization of Battery-
      Electric Vehicles for 1980-1990," Minicars, Inc., Golata, CA,
      submitted by General Research Corp., Prime Contract No, EPA-
      68-01-2103, January 1974.

181.  Hamilton, William F., "Use of Electric Cars in the Los Angeles
      Region 1980-2000," Preliminary draft RM1891 (EPA sponsored Elec-
      tive Car Impact Study), General Research Co.,  Santa Barbara, CA,
      April 1974.

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                                 251
182.  Foote, L.R., D.R. Hamburg, J.E. Hyland, C.W. Koop,  W.H.  Koch,  and
      L.E. Unnever, "Electric Vehicle Systems Study," Technical Report
      No. SR-73-132, October 25, 1973, Ford Motor Co.,(Abbreviated ver-
      sion:  See Ref. 183.)

183.  Unnever, Lewis, "Electric vehicle systems study," Paper  No.  7414,
      Third International Electric Vehicle Symposium, Washington,  DC,
      February 19-22, 1974, (UNIPEDE) (More detailed version:   See Ref.
      182.)

184.  Hagey, Graham and William F. Hamilton, "Impact of electric cars
      for the Los Angeles Intrastate Air Quality Control  Region,"
      Paper No. 7470, Ibid.

185.  Bader, C.} and H.G. Plust, "Electrical propulsion systems for
      Road Vehicles; State of the Art and Present Day Problems," Paper
      No. 7478, Ibid.  Also, Elektrische Antriebe fur Straszenfahrzeuge,
      ETZ-A, 11,637  (1973).

186.  "How Ford Evaluates Three Types of Electric Vehicles," Automotive
      Engineering, LXXXII, No. 6, pp. 37-41, 75, June 1974.

187.  Busi, James D., and Lawrence R. Turner, "Current Developments  in
      Electric Ground Propulsion Systems, R&D Worldwide," Journal  of the
      EJLectrochem. Soc. , CXXI, 183C, June 1974.

188.  Healy, Timothy J., "The Electric Car:  Will It Really Go?"  I^EE
      Spectrum, April 1974.

189.  Linnenbom, V.J., "Battery Powered Buses in London,"  Office  of
      Naval Research, European Scientific Notes, ESN028-6, June 28,  1974.

190.  Gross, Sidney, "Review of candidate batteries for electric vehicles,"
      Battery Council International, preprint, Annual Meeting, London,
      May 12-17, 1974.

191.  Kamada, K. , I. Okazaki, and T. Takagaki, "Hew lead  acid  batteries
      for electric vehicles and approach to their evaluation method,"
      Paper No. 7429, Third International Electric Vehicle Symposium,
      Washington, DC, February 19-22, 1974, (UNIPEDE).

192.  "Research on Electrodes and Electrolyte for the Ford Sodium-
      Sulfur Battery," Quarterly Report, Scientific Research Staff,
      Ford Motor Co., KSF Contract NSF-C8Q5, January 1-March 1, 1974.

193.  Sudworth, James L., "Some Aspects of Sodium Sulfur  Battery Design,"
      Preprint, 1974.

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                                 252
194.  Appleby, A.JC, J.J. Pompon,  and M.  Jacquier,  "Zinc-air batteries
      in vehicular applications," Paper No,  7430,  Third International
      Electric Vehicle Symposium,  Washington,  DC,  February 19-22,  1974,
      (UNIPEDE).

195.  Nelson, P.A.,  A.A.  Chilenskas, R.K. Stuenenberg," The Need for
      Development of High Energy Batteries for Electric Automobiles,"
      ANL-8075 (DRAFT), Argonne National  Laboratory,  January 1974.

196.  Salihi, Jalal  T., "Energy Requirements for Electric Cars and
      Their Impact on Electric Power Generation and Distribution Systems,"
      IEEE Transactions on Industry Applications,  "Vol. IA-IX, Ho. 5,
      September/October 1973.

197-  Altendorf,  J.P., A. Kaberlah and H. Saridakis,  "A comparison
      between a pick-up van with internal combustion engines and
      an electric pick-up van," Paper Ho. 7445, Third International
      Electric Vehicle Symposium,  Washington,  DC,  February 19-22,  1974,
      (UNIPEDE).

198.  Woukj Victor and Charles L.  Rosen,  "Preliminary evaluation E.F.A.
      test on PEM hybrid preliminary 'improvement package' information
      for Phase II,  F.C.C.I.P.," Paper No. 9336 Preliminary, April 4, 1974.

199.  Mapham, Heville, "Conservation of petroleum resources by the use
      of electric cars," preprint 740171, SAE  Automotive Engineering
      Congress, Detroit,  MI, February 25-March 1,  1974.

200,  Austin, A.L.,  "A Survey of Hydrogen's  Potential as a Vehicular
      Fuel," Lawrence Livermore Laboratory,  Report Ho.  UCRL-51228,
      June 1972.

201,  Pangborn, J.B., and J.C. Gillis, "Feasibility Study of Alternative
      Fuels for Automotive Transportation," Institute of Gas Technology,
      Interim Report on Contract Ho. 68-01,211, presented at AAPS
      Coordination Meeting, May 1974.

202.  Discussions with J. Pangborn  (IGT), August 15,  1974.

203.  Kant, F.H., "Feasibility Study of Alternative Automotive Fuels,"
      Exxon Research and Engineering Co., Report No.  EPA-460/3-74-009,
      June 1974.

204.  Jaffe, H.,  et al. , "Methanol from Coal  for the Automotive Market,"
      USAEC, February 1974.

205.  Wentworth,  T.O., as quoted in "Outlook Bright for Methyl-Fuel,"
      Environmental Science and Technology,  VII, 1973,  p. 1002.

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                                  253
206.  Dutkiewicz, B.,  "Methanol Competitive with LNG on Long Haul,"
      The Oil and Gas  Journal. April 303 1973, p. 166.

207.  "Coal Technology:  Key to Clean Energy," Annual Report 1973-74,
      Office of Coal Research, U.S. Department of the Interior.

208.  Mills, G. and B. Ilarney, "Methanol - the 'New Fuel1 from Coal,"
      Chemtech, January 1974, pp. 26-31.

209.  Hammond, A., "A  Timetable for Expanded Energy Availability."
      Science, CLXXXIV, (1974), p. 367.

210.  Hord, J., "Cryogenic H£ and National Energy Needs," presented at
      Cryogenic Engineering Conference, August 1973.

211.  Billings, R., "Hydrogen Storage for Automobiles Using Metal Hy-
      drides and Cryogenics," presented at the Hydrogen Economy Miami
      Energy (THEME) Conference, March 1974.

212.  "Proceedings of  the Hydrogen Economy Miami Energy (THEME)
      Conference," Section 4, Metal Hydride Storage; Section 8, Hydrogen
      Storage in Vehicles, March 1974.

213.  King, R. , et al. , "The Hydrogen Engine:  Combustion Knock and the
      Related Flame Velocity," Transactions Engineering Institute of
      Canada, II, No.  4,  (1958), p. 143,

214.  de Boer, P.} W.  McLean, J. Fagelson, and H. Homan, "An Analytical
      and Experimental Study of the Performance and Emissions of a
      Hydrogen Fueled  Reciprocating Engine," 9th IECEC,  San Francisco,
      August 1974.

215.  Billings, R. and F.  Cynch, "Performance and Nitric Oxide Control
      Parameters of the Hydrogen Engine," Energy Research Publication
      73002, Provo, Utah,  April 1973.

216.  Finegold, J.,  et al.,   "The UCLA Hydrogen Car:  Design,
      Construction and Performance," SAE Paper No.  730507 (1973).

217.  	, and M.  Van Vorst, "Engine Performance with Gasoline
      and Hydrogen:   A Comparative Study," presented at  the Hydrogen
      Economy Miami Energy (THEME) Conference, March 1974.

218.  Adt, R.,  et al.,  "The  Hydrogen-Air  Fueled  Automobile," Proceed-
      ings 8th IECEC,   (1973), p.  194.

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                                 254
219,  Murray, R.,  R. Sehoeppel and C. Gray, "The Hydrogen Engine in
      Perspective," Proceedings 7th IECEC> San Diego, September 1972.

220.  Stebar, R, and F. Parks, "Emission Control with Lean Operation
      Using Hydrogen - Supplemental Fuel," SAE Paper No. 740187,
      February 1974.

221.  "Alcohols and Hydrocarbons as Motor Fuels," SP-254, Society of
      Automotive Engineers, Inc., New York, June 1964.

222.  Bolt, J. , "A  Survey of Alcohol as a Motor Fuel," Op Git., p. 1.

223.  Adelman, H., D. Andrews and R, Devoto, "Exhaust Emissions from a
      MethanoI-Fueled Automobile," SAE. Transactions , Paper No. 720693
      (1972).

224.  Ingamells, J,, "Discussion of SAE Papers 720692 and 720693,"
      SAE Transactions, (1972), p. 2108.

225.  Discussions  with R,  Hum, U.S. Bureau of Mines., Bartlesville
      Energy Research, April 11, 1974.

226.  IngamellSj J. and R. Lindqulsts "Methanol as a Motor Fuel," sub-
      mitted by Chevron Research Co., (to be published in Science).

227.  Starkinan, E., H. Newhall and R. Sutton,  "Comparative Performance
      of Alcohol and Hydrocarbon Fuels," Reference 221, p. 14.

228,  Ebersole3 G. and F.  Manning, "Engine Performance and Exhaust
      Emissions:  Methanol versus Isoctane," SAE Transactions, Paper
      No. 720692 (1972),

229.  Pefley, R.,  M. Saad, M. Sweeney, and J.  Kilgroe, "Performance
      and Emission Characteristics Using Blends of Methanol and Dis-
      sociated Methanol as an Automotive Fuel," Pr_ogeed 1 ngs of 6th
      IECEC, (1971), p. 36.

230,  Reed., T, and R. Lerner, "Methanol:  A Versatile Fuel for Immediate
      Use," Science, CVXXXII, (1973), p. 1299.

231.  Gallopoulos, N., "Alternate Fuels for Automobiles," General
      Motors Research Laboratory; data submitted during panel of consul-
      tants visit  March 293 1974.

232,  "Use of Alcohol in Motor Gasoline - A Review," American Petroleum
      Institute, API Publication No, 4082, Washington, DC (1971).

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                                 255
233,  Reed,, T. , personal communication. May 1974.

234,  Lerner, R.Me, et al. ,  "Improved Performance of Internal Combus-
      tion Engines Using 5-20°i Methanol," (to be published).

235.  NASA Lewis Research Center, Hydrogen Generator Program, informa-
      tion provided during site visit, April 1974.

236.  Breshears, R. , H. Cotrill and J. Rupe, "Partial Hydrogen Injec-
      tion into Internal Combustion Engines, Effect on Emissions and
      Fuel Economy," Jet Propulsion Laboratory Project Briefing,
      February 1974.

237,  Discussions with Dr. Fred Dryer, Princeton University, August 16,
      1974.

238,  "Evaluation of ?areb-10 Fuel Mixture," California Air Resources
      Board, January 1974.

239,  Freeh, K.J., and J.J. Tazuma, U.S. Patent Ho. 3822119.  Also,
      discussions with Dr. James Tazuma, Goodyear Research Laboratories,
      August 16, 1974.

240,  "Water/Alcohol Solutions in Internal Combustion Engine Fuel
      Systems," Emission Free Fuels, Sparta, KJ3 December 1973.

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                                APPENDIX A
                 Organizations Contacted by Members of the
Panel of Consultants on Engine Systems
1.
2.
3.
4.
5.
6,
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Ford Motor Co., Dearborn, MI
Chrysler Corp., Detroit, MI
Environmental Protection Agency,
Ann Arbor , MI
Chrysler Corp., Detroit, MI
Ford Motor Co., Ann Arbor, MI
General Motors Corp., Warren, MI
California Air Resources Board,
Los Angeles, CA
Dresser Industries, Santa Ana, CA
Philco-Ford, Newport Beach, CA
New York City Air Resources Board,
New York, NY
Curtiss -Wright Corp., Wood-Ridge, NJ
Texaco, Inc., Beacon, NY
Universal Oil Products,
Des Plaines, IL
Bendix, Detroit, MI
Ethyl Corp., Ferndale, MI
Holley Carburetor, Detroit, MI
Yanmar Diesel, Osaka, Japan
1/17/74
1/17/74
1/23/74
2/12/74
2/13/74
2/14/74
3/20/74
3/21/74
3/21/74
3/26/74
3/27/74
3/28/74
4/16/74
5/7-8/74
5/7-8/74
5/7-8/74
5/9/74
*John
John
John
John
John
John
John
John
John,
John
John,
John
John,
John,
John,
John,








Newhall

Wulfhorst

Jost
Jost
Jost
Jost
Wulfhorst
-«Last names of members of the Panel of Consultants on Engine Systems
                                   256

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                                    257
18.  Toyo Kogyo Co., Ltd.,                   5/10/74
       Hiroshima, Japan

19.  General Motors Corp., Warren, MI        5/15/74

20.  Ford Motor Co., Dearborn, MI            5/16/74

21.  Chrysler Corp., Detroit, MI             6/4/74

22.  TACOM, Detroit, MI                      6/4/74

23.  Questor Corp., Toledo, OH               6/6/74

24.  Shell Research Ltd., Thornton, England  6/14/74

25.  Ricardo & Co. Engineers, Ltd.,          6/17/74
     Shoreham-by-the-Sea, England

26.  British Leyland Ltd.,                   6/18/74
       Coventry, England

27.  C.A.V., London, England                 6/18/74

28.  Toyo Kogyo Co., Ltd.,                   6/18/74
       Hiroshima, Japan

29.  Toyota Motor Co., Ltd., Aichi, Japan    6/18/74

30.  Honda R&D Co., Ltd., Saitama, Japan     6/19/74

31,  Perkins Engine Co.,                     6/19/74
       Peterborough, England

32.  Volkswagenwerk AG,                      6/19//4
     Wolfsburg, W. Germany

33.  Daimler-Benz AG, Stuttgart, W. Germany  6/20/74

34.  General Motors Technical Center,        6/20/74
       Warren, MI

35.  Japan Motor Vehicle Research            6/20/74
       Laboratory, Osaka, Japan

36.  Nissan Motor Co., Ltd., Tokyo &         6/20/74
       Yokosuka, Japan
Wulfhorst


John, Newhall

John, Newhall

John

John

John

John

John, Henein, Jost


John, Jost


Henein

Newhall


Newhall

Newhall

Henein


John,  Jost


John,  Henein, Jost

Wulfhorst


Newhall


Newhall

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                                    258
37.  Daihatsu Kogyo Co., Ltd., Osaka,  Japan  6/21/74        Newhall




38.  Robert Bosch GMBH, Postfach,  W.  Germany 6/21/74        John,  Henein,  Jost




39.  Audi, Ingolstadt, W.  Germany             6/22/74        John,  Jost




40.  Ford Motor Co., Dearborn, Ml             7/9/74          Newhall




41.  Gould, Inc., Cleveland,  OH              7/9/74          John




42.  General Motors Corp.,  Warren,  MI         8/1/74          John

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                                    259

                                 APPENDIX B
                  Organizations Contacted by Members of the
                  Panel of Consultants on Alternatives
 1,  Environmental Protection Agency,       1/22-23/74,      -Bjerklie,  Tobias
      Ann Arbor, MI                        3/27/74, 7/2/74

 2.  ACAAPS Review Meeting, Washington, DC  2/11/74           Bjerklie

 3.  Chrysler Corp., Detroit, MI            2/12/74, 3/28/74  Bjerklie,  McLean,
                                                             Wilson

 4.  Ford Motor Co., Dearborn, MI           2/13/74, 3/28/74  Bjerklie,  McLean,
                                                             Wilson

 5.  General Motors Corp., Warren, MI       2/14/74, 3/26/74  Bjerklie,  Tobias

 6.  Society of Automotive Engineers        2/27/74           Bjerklie
      Meeting, Detroit, MI

 7.  Petro-Electric Motors, Ltd.,           March 1974        Bjerklie
      New York,  NY

 8.  Massachusetts Institute  of Technology, 3/8/74,           Bjerklie,  McLean
      Boston, MA                          May 1974

 9.  Scientific  Energy Systems,             3/8/74            Bjerklie,  McLean,
      Watertovn, MA                                          Wilson

10.  Thermo-Electron  Corp., Waltham, MA     3/8/74            Bjerklie,  McLean,
                                                             Wilson

11.  United  Stirling  (Sweden)  in  Boston, MA 3/15/74          Bjerklie

12.  The Hydrogen Economy Miami Energy     3/18-19/74       McLean
       (Theme)  Conference, Miami  Beach, FL

13.  Institute  of Gas Technology,           3/25/74,  8/15/74  McLean
       Chicago,  IL

14.  Williams  Research, Detroit,  MI        3/27/74          BjerkLie, Wilson


*Last  names  of  members of the Panel of Consultants  on Alternatives

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                                     260
15.  Exxon Res, & Eng.,  Linden, NJ

16,  Brobeck Associates, Berkeleys CA

17.  Chevron Research Co., Richmond,CA

IB.  University of California (Berkeley) CA

19.  Jet Propulsion Lab., Altadena, CA

20.  Solar, San Diego, CA

21.  Steam Power Systems, San Diego, CA

22.  Bartlesville Energy Research Center
     (U.S. Bureau of Mines) Barltesville,OK

23.  Kinergetics, Tarzana, CA

24,  Philips Petroleum,  Bartlesville, OK

25,  Zwick Co., Santa Ana, CA

26.  Jay Carter Enterprises, Burkburnett,TX

27.  NASA Lewis Research Center,
       Cleveland, OH

28.  DAUG, Stuttgart, W. Germany

29.  British Railway Tech. Ctr.,
       Derby, England

30_  Philips Research Labs.3
       Eindhoven, Ho Hand

31,  United Stirling, Malmo, Sweden

32.  MAN-MWM, Augsburg,  W. Germany

33.  Volkswagenwerk AG,  Wolfsburg,
       W. Germany

34.  Princeton University, Princeton, NJ

35.  Goodyear Research Labs», Akron, OH
4/3/74
4/8/74
4/8/74
4/8/74
4/9/74
4/10/74
4/10/74
4/11/74
4/11/74
4/11/74
4/11/74
4/12/74
4/12/74
5/15/74
5/16/74
5/20/74
5/21/74
5/22/74
5/24/74
8/16/74
8/16/74
McLean
Bjerklie
McLean
McLean
Bjerklie, McLean
Bjerklie, McLean
Bjerklie
McLean
Bjerklie
McLean
Bjerklie
Bjerklie
McLean
Bjerklie
Bjerklie
Bjerklie
Bjerklie
Bjerklie
Bjerklie
McLean
McLean
                                           U.S. GOVERNMENT PRINTING OFFICE; 197S— 5B2-4I»:2J4

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