EPA-460/3-74-011-b
October  1975
                            A STUDY
       OF  STRATIFIED CHARGE
                FOR  LIGHT  DUTY
                   POWER PLANTS
                          VOLUME 2
     U.S. ENVIRONMENTAL PROTECTION AGENCY
         Office of Air and Waste Management
     Office of Mobile Source Air Pollution Control
         Kmission Control Technology Division
            Ann Arbor, Michigan 48105

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                                    EPA-460/3-74-011-b
            A  STUDY
OF STRATIFIED CHARGE
     FOR  LIGHT  DUTY
       POWER PLANTS
           VOLUME 2
                  by

   Ricardo and Company Engineers (1927) Ltd.
              Bridge Works,
   Shoreham-by-Sea, Sussex, England BN4 5FG
           Contract No. 68-03-0375



            EPA Project Officers:

        T.C. Austin and J.J. McFadden



               Prepared for

   U.S. ENVIRONMENTAL PROTECTION AGENCY
      Office of Air and Waste Management
   Office of Mobile Source Air Pollution Control
      Emission Control Technology Division
          Ann Arbor,  Michigan 48105

               October 1975

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     This report is issued by the Environmental Protection Agency to report
 technical data of interest to a limited number of readers.  Copies are avail-
 able free of charge to Federal employees, current contractors and grantees,
 and nonprofit organizations - as supplies permit - from the Air Pollution
 Technical Information Center, Environmental Protection Agency, Research
 Triangle Park, North Carolina 27711; or, for a fee, from the National Technical
 Information Service, 5285 Port Royal Road, Springfield, Virginia 22151.
     This report was furnished to the Environmental Protection Agency by
Ricardo and Company Engineers (1927) Ltd., Shoreham-by-Sea, Sussex, England, in
fulfillment of Contract No. 68-03-0375.  The contents of this report are repro-
duced herein as received from Ricardo and Company Engineers (1927) Ltd.  The
opinions, findings, and conclusions expressed are those of the authors and not
necessarily those of the Environmental Protection Agency.  Mention of company
or product names is not to be considered as an endorsement by the Environ-
mental Protection Agency.
                        Publication No. EPA-460/3-74-011-b
                                    11

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                           TABLE OF CONTENTS
                                                                          Page
LIST OF FIGURES	 .     iv
LIST OF TABLES. . .	    Vii
ABSTRACT	viii
SUMMARY	      1
ENGINE CONFIGURATION STUDY	      3
   Introduction 	      3
GASOLINE ENGINE 	 	      7
ENGINE CONFIGURATION WITH CATEGORY 1	     11
ENGINE CONFIGURATIONS WITHIN CATEGORY 2 . 	 ...     19
ENGINE CONFIGURATIONS WITHIN CATEGORY 3 	     34
ENGINE CONFIGURATIONS WITHIN CATEGORY 4 . .	     38
ENGINE CONFIGURATIONS WITHIN CATEGORY 5 	 	     43
COST ANALYSIS	     94
POWER PLANT RATING	     97
   Summary	     97
POWER PLANT RATING	     98
   Introduction	     98
   Results	    119
   Conclusions	    119
DISCUSSIONS AND RECOMMENDATIONS	    121
   General Discussion 	 ....    121
   General Conclusions	    126
   General Recommendations	    129
   Acknowledgments  	    130

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                             LIST OF FIGURES
Figure                                                                    Page

   1        Estimated Performance Curve for 0  97  x  76  mm V8 Gasoline
           Engine for Primary Emission Target.                              50

   2        Estimated Performance Curve for 0  88  x  82  mm 6  Cylinder
           "European Type"  Gasoline Engine for Primary Emission
           Target.                                                          51

   3        Estimated Performance Curve for 0  87  x  87  mm V8 Configu-
           ration - Category 1.                                             52

   4        E.P.A. Light Duty Stratified Charge Project, Task  II  -
           Configuration Study.   Category I - V8 Ford 'PROCO'
           System,  Installation  Drg.,  Primary Emission Target.              53

   5        E.P.A. Light Duty Stratified Charge Project. Task  II
           Configuration.   Category I  - V8 Ford  'PROCO1  System,
           Cylinder Head Layout, Primary Emission  Target.                   54

   6        E.P.A. Light Duty Stratified Charge Project.  Task  II
           Configuration Study.   Category I - V8 Ford 'PROCO'
           System,  Cross Section Arrangement, Primary Emission
           Target.                                                          55

   7        Estimated Performance Curve for 0  96  x  96  mm In-line
           6 Configuration  - Category  1.                                    56

   8        E.P.A. Light Duty Stratified Charge Project.  Task  II
           Configuration Study.   Category 1 - In-line 6 Ford
           'PROCO1  System,  Installation Drg., Primary Emission
           Target,                                                          57

   9        E.P.A. Light Duty Stratified Charge Project.  Task  II
           Configuration Study.   Category I - In-line 6 Ford
           'PROCO1  System,  Cross-sectional  Arrangement, Primary
           Emission Target.                                                 58

  10        Estimated Performance Curve for 0  94  x  94  mm V8
           Configuration -  Category 1.                                      59

  11        E.P.A. Light Duty Stratified Charge Project.  Task  II
           Configuration Study.   Category I - V8 Ford 'PROCO1
           System,  Installation  Drg.,  Secondary  Emission Target.            60

  12        Maximum  Power Operating  Conditions for  LI41  TCCS
           Engines  at Two Smoke  Levels.                                     61

  13        Indicated Specific Air Consumption for  LI41  TCCS
           Engines  at Two Smoke  Levels.                                     62


                                   iv

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Figure                                                                    Page

  14       Motoring Friction of LI41  TCCS Engines.                          63

  15       Estimated Performance Curve for 0 95 x 95 mm Naturally
           Aspirated V8 Configuration - Category 2.                         64

  16       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category I - V8 Naturally Aspirated
           TCCS System, Installation  Drg.s Primary  Emission Target,         65

  17       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category I - V8 Naturally Aspirated
           TCCS System, Cylinder Head Drg., Primary  Emission Target.       66

  18       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category II - V8 Naturally Aspirated
           Texaco  TCCS System,  Primary Emission Target, Cross Sec-
           tional  Arrangement.                                              67

  19       Calculated Variation in  Boost Density Ratio  and Air Fuel
           Ratio for the Configurated Turbocharged TCCS Engine.             68

  20       Relationship Between Indicated Fuel Consumption and
           Air Fuel  Ratio for a TCCS  Engine.                               69

  21       Estimated Performance Curve for 0 96 x 96 mm Turbocharged
           In-line 6 Configuration  -  Category 2.                           70

  22       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category II - In-line  6 Turbo-
           charged TCCS System, Installation Drg., Primary Emis-
           sion Target.                                                    71

  23       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category II - In-line  6 Turbo-
           charged TCCS System, Cylinder Head Drg.,  Primary Emis-
           sion Target.                                                    72

 •24       E.P.A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.  Category II - In-line  6 Turbo-
           charged TCCS System, Cross-sectional  Arrangement, Pri-
           mary Emission Target.                                            73

  25       Estimated Performance Curve for 2 Bank Rotary Engines  -
           Category  2.                                                      74

  26       E.P..A.  Light Duty Stratified Charge Project.  Task II
           Configuration Study.   Category II - 2 Bank Rotary,
           Installation Drg., Primary Emission Target,                      75

  27       E.P.A.  Light Duty Stratified Charge Project.   Task II
           Configuration Study.   Category II - 2 Bank Rotary,
           Cross and Longitudinal Sectional  Arrangement,  Primary
           Target.                                                          76

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Figure                                                                   Page

  28       Calculated Variation  of Boost  Density  Ratio  for  Configu-
           rated Turbocharged TCCS Engine.                                 77

  29       Estimated Performance Curve  for  0  101  x  92 mm  V8 Turbo-
           charged Configuration - Category 2.                             78

  30       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category II  -  V8 Turbocharged TCCS
           System, Installation  Drg., Secondary Emission  Target.           79

  31        Estimated Performance Curve  for  0  93 x 93 mm V8  Configu-
           ration  - Category  3.                                            80

  32       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category III - Y8  N/A  -  M.A.N.  FM
           System, Installation  Drg., Primary Emission  Target.             81

  33       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category III - V8  Naturally
           Aspirated M.A.N. FM System,  Primary  Emission Target,
           Cylinder Head Drg,                                              82

  34       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category III - V8  Naturally Aspirated
           M.A.N.  FM System,  Primary Emission Target, Cross Sectional
           Arrangement.                                                    83

  35       Estimated Performance Curve  for  0  86 x 79 mm Naturally
           Aspirated V8  Configuration - Category  4.                       84

  36       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category IV  -  V8 VW System,
           Installation  Drg.,  Primary and Secondary Emission Target        85

  37       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category IV  -  V8 VW System, Cylinder
           Head  Drg.,  Primary and Secondary Emission Target.              86

  38       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category IV  -  V8 VW System, Cross-
           sectional  Arrangement, Primary and Secondary Emission
           Target.                                                        87

  39       Estimated Performance Curve  for  0  88 x 88 mm V8  Configu-
           ration  - Category  5.                                            88

  40       E.P.A.  Light  Duty  Stratified Charge  Project.   Task  II
           Configuration Study.   Category V - V8  CVCC System,
           Installation  Drg.,  Primary Emission  Target.                     89
                                   VI

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Figure                                                                    Page

  41       E.P.A. Light Duty Stratified Charge Project.   Task II
           Configuration Study.   Category V - V8 CVCC System,
           Cylinder Head Layout, Primary Emission Target.                  90

  42       E.P.A. Light Duty Stratified Charge Project.   Task II
           Configuration Study.   Category V - V8 CVCC System,
           Cross-sectional  Arrangement, Primary Emission Target            91

  43       Estimated Performance Curve for 0 96 x 96 mm V8 Con-
           figuration - Category 5.                                        92

  44       E.P.A. Light Duty Stratified Charge Project.   Task II
           Configuration Study.   Category V - V8 CVCC System,
           Installation Drg,, Secondary Emission Target.                   93

  Dl       Proposed Alternative  Approach for Combustion  Initiation
           in Reciprocating Internal  Combustion Engine.                    131
                            LIST OF TABLES

          Summary Table                                                   49

          Stratified Charge Engine - Feasibility Study                    96
                                 vii

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                               ABSTRACT
     The objectives of this project were to determine the acceptability of
various types of stratified charge engines as potential  power plants for
light duty vehicles and motorcycles in America.  The light duty vehicle
considered was a 4/5 seat compact sedan with good acceleration capabilities
and exhaust emissions below a primary target of 0.41 g/mile HC, 3.4 g/mile
CO, 1.5 g/mile NOX.  A secondary target of 0.41 g/mile HC, 3.4 g/mile CO
and 0.4 g/mile NOX was also considered,

     A literature survey was undertaken, comparing stratified charge
engines with examples of good conventional gasoline and diesel engines.
While some stratified charge engines had exhaust emission or fuel  economy
advantages, there were always sacrafices in other areas.

     Eleven engines were configured, four of which were specifically
directed towards the secondary emission targets.  A method rating  the
engines was derived, and the design concepts were compared with two gasoline
engines by a jury panel.  The overall result was that the Ford 'PROCO' and
Honda CVCC combustion processes were serious contenders to the gasoline
engine at the primary emission target, and that both of these systems,
together with the VW combustion process, might be suitable at the  secondary
targets.

     This section of the report covers the engine configuration study and
power plant rating, as well as the overall conclusions and recommendations
from the complete project.
                                 vi i i

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     Some of the terms  mentioned  In  the  text  of  this  report  may  not  be  familiar
to the reader,  so the  following glossary has  been  compiled.

          CVS-CH     1975  cold/hot start Federal  test  procedure  using
                    CVS equipment.

          01         Di rect  Inject ion

          EFI        Electronic fuel  injection

          EGR        Exhaust  gas  reelrculation

          IDI         Indirect  Injection  (i.e.  into a  pre-chamber)

          mbt         Ignition  spark  at minimum advance for  best  torque

          mpg        Fuel  economy  In miles per U.S. gallon

          NA        Naturally aspirated

          RON        Fuel  Research octane number

          T/C        Turbocharged
                                   IX

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 SUMMARY

     This  section contains details of the stratified charge gasoline engine con-
 figurations which were  schemed as potentially viable  light duty power plants.
 Information on  two conventional gasoline power plants  Is also  included for com-
 parison.

     The stratified charge power plants were all designed to propel the target
 vehicle for the study,  a 4-5 seat sedan with a maximum curb weight of 1600 kg
 (3500  Ib)  capable of  0-96 km/h  (0-60 mph)  In 13.5 s and 40-112 km/h (25-75 mph)
 In  15  s.   Computer calculations Indicated  that a bare engine power of about 96 KW
 (128 bhp)  was required  If a conventional 3-speed automatic transmission was used.

     The range of engine configurations presented for  each of the seven stratified
 charge categories was  largely dictated by  the combustion limitations of each
 category.   In general,  the configurations  were schemed using combustion layouts
 which  have been proven  and for which published performance results could be used,
 In  order  that the performance of the proposed power plants could be predicted.

     The following engines were configurated, in order  to achieve the primary
 emission  target  (HC 0.4l g/mile, CO 3.4 g/mlle, NO  1,5 g/mlle) and also the
 secondary  emission target (HC 0.41 g/mlle, CO 3.4 g/mlle, NO   0,4 g/mile):-
                                                            ?\

 Category  1

 Primary Emission Target

 (1)  V-8,  4.12  1, PROCO combustion system

 (2)  Inline 6, A.16 1,  PROCO combustion system

 Secondary  Emission Target

 (3)  V-8,  5.25  1, PROCO combustion system,

 Category  2

 Primary Emission Target

 (1)  V-8,  5.4 1, TCCS combustion system

 (2)  V-8,  4,16  1, Turbocharged TCCS combustion system

 (3)  2 Bank, Rotary,  5.5 lf CurtIss-WrIght combustion  system

 Secondary  Emission Target

 (4)  V-8,  5.8?  1, Turbocharged, TCCS combustion system

Category  3

 Primary Emission Target

 (0  -V-7,  5.06  1, MAN-FM combustion system

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Category fr

Primary Emission Target

 (1)  V-8, 3.67  1, VW combustion system

Secondary Emission Target

 (2)  As above

Category 5

Primary Emission Target

 (1)  V-8, k.26  1, CVCC combustion system

Secondary Emission Target

 (2)  V-8, 5.58  1, CVSS combustion system

Category 6

No configurations

Category 7

No configurations

    Drawings and performance curves were prepared for all  the above  engines,  each
configuration being schemed In sufficient detail  to allow  a  reliable assessment
of its potential.  The In-vehlcle characteristics of the power plant,  i.e.
emissions,  fuel consumption and noise, were estimated on the basis of previous
engine performance in cars and on test beds,  of each combustion  system.

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                           ENGINE CONFIGURATION STUDY

INTRODUCTION

    The literature survey gives a preliminary and overall  comparative analysis
of the potential of each category of stratified charge engine as a light duty
power plant.   The aim of this configuration study is to enable a quantitative
assessment to be made of all the characteristics of those stratified charge engines
which were considered feasible as light duty power plants.  This is achieved by
scheming the engines specifically for a particular vehicle and emissions
envlronment.

Definition of Vehicle

    The vehicle selected for this study was a passenger car (typically a V5 seat
sedan) with a maximum test Inertia of 1600 kg (3500 1b) when loaded and capable of
meeting the EPA standard car performance specifications, i.e.  0-97 km/h (0-60 mph)
in less than 13-5 s, 1*0-112 km/h  (25-70 mph) In less than 15 s, and capable of
overtaking an 80 km/h (50 mph) truck in less than 15 s.

    To assist in the definition of the power plant a computer program was written
to allow the maximum power output of the engine, the shape of Its torque curve and
the transmission system necessary to achieve these acceleration capabilities to be
calculated.

    Use of this program showed that with a three-speed automatic gearbox and with
the final drive ratios selected to give approximately 136 km/h (85 mph) at the
rated engine speed, a bare engine power of 96 KW (128 bhp) was required to satisfy
the acceleration target.  This Implies that the vehicle has acceleration "in hand"
at this rated speed and thus a non^speed limited engine will permit maximum speeds
on level roads to be greater than this nominal figure.  Various gear ratios and
amounts of torque back-up were tried and the minimum power plant requirements were
finally selected as:-

              Rated Speed            96 KW      128 bhp
              .75 Rated Speed        76 KW      102 bhp
              .50 Rated Speed        53 KW       71 bhp
              .25 Rated Speed        17 KW       22.7 bhp

    The detailed shape of the torque curve which is dependent on the particular
characteristics of each stratified engine variant is not a critical factor in
achieving the above performance requirements.

Target Emissions

    For the purposes of this study two target emission levels were envisaged.
These were?-

Primary (or short term)

                        HC          0.1*1 g/mi le

                        CO          3.4  g/mile

                        NO          1.5  g/mlle

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Secondary (or long term)

                        HC          0.41 g/mlle

                        CO          3.4  g/mlle

                        NO          0.4  g/mlle

    The above levels were selected essentially as  the  proposed  'Interim' Federal
emissions levels and the statutory 'final1 limits  as prescribed under the Clean
Air Act.

Configuration Notes

    Each configured engine Is described by a separate  specification and performance
table followed by notes on

    (a)  the predicted performance characteristics  of the  engine, and

    (b)  design notes which make reference to the performance curves and
        design schemes  Included In the text,

    At the end of the Configuration Study a Summary Table Is shown which allows  an
overall comparison to be made of all  the engine configurations,  The  Summary Table
also Includes details of the gasoline and dlesel  I.D.I, engines.

    The following considerations were taken Into account  when estimating the
performance levels of each engine/vehicle*-

(1) Any emission control system should be able to  operate for 50,000  miles  or at
    least 25,000 miles with little maintenance in  order to warrant practical  con-
    sideration,  Factors such as the physical  Integrity of the  specialised  exhaust
    system, spark plug  life, deterioration of the  catalysts, thermal  reactors and
    EGR system have been considered when predicting  the emission durability of
    each engine configuration.
    <
(2) In the summary table, the engine baseline HC and CO exhaust emissions are
    presented as well as controlled levels,  Because of the different exhaust
    flow rates, exhaust temperatures and engine baseline  emissions each category
    of stratified charge engine requires a different method of  exhaust oxidation
    treatment, the severity of which generally Increases  with the baseline
    emission level.  The baseline HC and CO emissions  have Included the effects
    of EGR where fitted, therefore no baseline NO   emissions are quoted.

    Exhaust emissions were estimated by consideration  of  the performance of each
    combustion system In vehicles and from test bed  results.

(3) In the case of those engines which have a smoke  limited performance, the
    torque curves are restricted to give smoke levels  ranging from approximately
    7%  opacity at low speed to 2\% opacity at the rated  speed.   It is  felt that
    smoke levels higher than these would be totally  unacceptable for  a  passenger
    car engine.

(4) Prediction of the fuel  consumption on the CVS-CH  test cycle for each engine
    configuration was based on the results from a  range of test engines and
    vehicles uncovered by the literature survey.   PublIshed data was  usually too
    sparse to allow a more thorough comparison to  be made between the stratified
    charge variants,   However, the CVS-CH test comparison Is now accepted as

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     reflecting  the  true  differences between systems since the cycle simulates
     typical  urban driving  conditions.  The fuel consumption has been predicted
     while  assuming  the vehicle  to have automatic transmission without lgck*up,
     With a manual gearbox  the fuel consumption will be  Improved by around 5*6%,

(5)   Noise  emission  predictions  were based on a distance of 15 m from the test
     vehicle  during  the American drive-by procedure according to SAE J986A,
     Established formulae were used which are known to be accurate for both
     diesel and  gasoline  engines,  The method was:-

   (a)   prediction of the noise  level of an equivalent conventional gasoline
        engine of the same  bore

   (b)   adjustment of this  level by a correction factor  based on either measured  .
        comparative  noise emissions or by consideration  of the combustion pressure
        diagram  and  engine  structure.

     These  noise levels  could be reduced by up  to 3 dBA  by the use of engine
     shielding.

     Design points which  are applicable  to all  the  reciprocating engines are  as
follows:-

(1)   Cast  Iron was  universally applied as  the cylinder block material for high
     strength and low cost  with  integral cylinder bores.  Cast  iron was also
     used  for all cylinder  heads.

(2)   The major  dimensions,  design and  rigidity  of the  crankcase  and crankshaft
     followed conventional  gasoline  engine practice  in the cases when the maximum
     cylinder pressures  were equivalent  to those of a  gasoline  engine.   In  all
     cases  the  piston ring  pack  was  designed  for gasoline engine practice with
     two compression rings  and one oil  control  ring.

(3)   Crankshaft  bearing  loadings were  based on  the  maximum cylinder pressure  and
     taking Into account  the bearing overlap  but without inertia relief.  All
     connecting  rods were straight"Cut.

(4)   The cylinder head combustion gas  face was  made  flat and  parallel to  the
     cylinder head deck  for simplicity  of  manufacture  in most  of the  configurations
     Exhaust  valve seats  were also Induction  hardened  to prevent valve  seat
     recession  which can  occur with  unleaded  gasoline,

(5)   Valve  gear  generally adopted followed current  American  gasoline  engine
     practice with pushrod  operated  valves,  pressed  steel  rockers  and hydraulic
     tappets.  On the V-8 configurations a  single  central  camshaft was  chosen
     for compactness and simplicity.   Overhead  camshafts were  not  considered  to
     offer  any  significant  advantages  for  this  application and  speed  ranges
     although In one case it proved  necessary  In order  to relieve  cylinder  head
     congestion,

(6)   The choice  of a 90° V-angle for all  the  V-8 configurations  was  influenced  by
     current  American practice.. With  a  cruciform crankshaft  complete external
     balance  and equal engine firing  intervals  are  obtained.   Complete  external
     balance  is  also obtained with the  In-line  6 configurations  together  with
     equal  firing Intervals.

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(7)   V-8 balance:  There Is complete balance of  the  primary forces, secondary
     forces and secondary couples.  Primary couples  are  fully balanced by means of
     suitable crankshaft balance weights.

     In-line 6 balance*  Complete primary  and secondary  balance Is achieved.  The
     crankshafts are provided with counterweights  to relieve Inertia loads on end
     and central main bearings.

(8)   For all the V-8 configurations the optimum  position for the Inlet manifold
     was found to be between the engine banks.   This position was generally
     determined by the need for  a single throttle  to be  conveniently positioned.
     Outboard Inlet manifolds make for difficult air control,  Synchronisation
     of two throttles, one per bank, would be necessary  or alternatively long
     Inlet tracts leading to a single throttle,

(9)   In the Interests of low noise the use of sound  deadened steel  material was
     used for the rocker box covers and oil  sump covers  on the V-8 configurations
     and additionally for the tappet inspection  covers on the In-line 6 con-
     figurations,

(10)  V-8 water circuit:  The water pump was  positioned on the front face of the
     block, discharging coolant  through both cylinder banks and returning via the
     cylinder heads to a collector with a  single outlet.

     In-line 6 water circuit: The water pump was  positioned on the front face
     of the block discharging directly into the  cylinder block,

(11)  The design of the complex fuel Injection systems for many of the engines
     assumed the use of present-day technology In  a  form that could be developed
     for production relatively quickly.  In  all  cases this has resulted in a  fully
     mechanical system as In the stratified  charge variants covered in the
     literature survey.  It Is quite possible that electronic fuel  injection  systems
     offer significant advantages, but a longer  development time would be
     necessary before production could begin,

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                                 GASOLINE ENGINE
     While no engine configuration studies have been carried out on standard
gasoline engines, It was necessary to have estimates of performance for comparison
with the various stratified charge engines.

     Two gasoline engines were studied, the first being a V-8 following current
American practice both  In design and performance, and the second a 6 cylinder
engine more typical of  European practice.

Category*  Standard Gasoline

V-8, Naturally Aspirated Engine - Primary Emission Target
Bore

Stroke

Bore/Stroke Ratio

Dlsplacement

Powe r

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max. Piston Speed
97 mm

76 mm

1 .28

*».5L

96 kW
     at 66.7 rev/s
                     3.82 in

                     3.0  in
                     275 in3

                     128 bhp
                            at ^000 rev/mi n
6.26 bar             91 lbf/ln2
7.9 bar
     at 'il .6 rev/s
285 Nm

25*

21 ,J» kW/L

10.2 m/s
                     115 lbf/in2
                            at 2500 rev/min
                     210 Ibf.ft
                     6.1»65 bhp/in3

                     2000 ft/min
Engine Weight

Predicted CVS-CH  results

Fuel Economy

Fuel Consumption

HC
CO
     BaselIne/Controlled
NO  Controlled
  x

Estimated Noise

Specific Performance  and  Emissions
2*»5 kg
16.0 mlles/U,S. gallon

14.6 L/100 km

1.8/0.2 g/mlle

30/1.0  g/mile

1.3 g/mile

71 dBA
                         Ib
     Using  typical  specific  performance  levels  for  this  type of  engine,  l.e,
21.0-22.0 kW/L  (0.46-0.48  bhp/in3),  the  target  power  output  demands  a  swept  volume
of 4.5 L  (275  In3).   This  capacity,  In conjunction  with  a  rated  speed  of 66.7  rev/s

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 (typical  of most  standard  American  engines)  produces  the target performance levels
 resultlnq In  satisfactory  driving characteristics with a simple three or four
 speed  transmission.   The performance  curves  for  this  engine can be seen In
 FIqure 1.

     The  performance  levels  can  be  achieved  with the  engine in low emissions build
 but external  hang  on  emissions control  devices are necessary, their complexity
 depending  on  the  severity  of the emissions target.  The primary project targets can
 be achieved by  using  close tolerance  sophisticated carburettors in conjunction with
 modulated exhaust  gas recycle, air  injection into the exhaust and an oxidation
 catalyst.  All  these  devices can be considered current technology and the various
 trade  offs for  low emissions are well  known  Cincreased power plant weiqht, first
 cost,  maintenance  cost, a  demand for  lead^free fuel,  and a depreciation in vehicle
 fuel economy) .

     A fuel economy of 16.0  miles/U.S.  gallon  (H.6 L/100 km) has been assumed for
 the gasoline  powered  vehicle when  In  the  primary target build.  This figure is
 representative  of  good gasoline  engines of this  type.  The philosophy adopted in
 the literature  survey of making  comparisons  with good, rather than average,
 gasoline  engines has  been  retained  for  this  study.  The estimated engine weight
 was 2*»5 kg (5^0 Ib).

     Using established noise prediction formulae, bare engine noise levels on a
 test bed  would  be  9^  dBA at  rated  load  and speed.  This correlates with a drive-by
 noise  level of  71  dBA at 15.23 m under  standard  American test conditions.

     The  secondary project emissions  objectives  of 0.*» g/mile NO  while maintaining
 HC and CO  levels,  demand the additional use  of a reducing catalyst and possible
 further catalytic  devices  (getter box)  to protect the reducing catalyst from
 oxygen spikes.  Due to the need  to  operate with  low oxygen concentration in the
 exhaust  (less' than 0.5%) It  Is necessary  to  run  with a mixture strength approaching
 stolchlometrlc  conditions  with a resultant fuel  economy penalty.   However, although
 the secondary target  emissions can  be  reached at zero miles, the present day
 reducing  catalysts have Insufficient  durability  to achieve the secondary target.
 Therefore  no gasoline engines were  configured for the secondary target.

 Category.  Standard Gasoline

 In-Line 6, Naturally  Aspirated Engine  - Primary  Emission Target

 Bore                                  88 mm                 3.^6 in
Stroke

Bore/Stroke Ratio

Displacement

Power

BMEP

Max. BMEP

Max, Torque

Torque Back-up

 8
82 mm

1 ,08

2.99 L

96 kW
     at 83.3 rev/s
7.6 bar

9-75 bar
     at 50 rev/s
232 Nm

20*
3.22 in
183 in3

128 bhp
       at  5000 rev/min
110 Ibf/in2

1M 1bf/in2
       at  3000 rev/min
171 Ibf.ft

-------
Power/Unit Displacement              32.1 kW/L             0.7 bhp/lr\

Max. Piston Speed                    13.6 m/s              2680 ft/m!n
Engine Weight                        2Qk kg                kSO 1b

Predicted CVS-CH Results

Fuel Economy                         17. *• miles/U.S. gallon

Fuel Consumption                     13.5 L/100 km

HC )                                 1.8/0.2 g/mlle
.._ ) Baseline/Controlled             ,n/. _   ...
CO )                                 30/1 .0 g/mi le

NO  Controlled                       1.3 g/mi le
  X

Estimated Noise                      73 dBA

     The first and obvious difference between American and European engines of
this power range Is that of specific performance.  Whereas the American V-8 gasoline
engine runs to around 67 rev/s and develops 21 kW/L (0.^7 bhp/In3), the European
engine runs to at least 83 rev/s and develops a minimum of 32 kW/L C0.7 bhp/in3),
normally nearer 36 kW/L (0.8 bhp/in3).  The major reason for these vastly
differing philosophies  Is one of economics^ mainly because of taxation, European
fuel prices have always been high in terms of real spending power with a resultant
continuing trend towards small capacity, high economy engines and cars.  On the
other hand, the price of fuel In America has always been low and fuel consumption
has never been a major  consideration until recently; engine size has therefore
Increased over the years to Improve drlveabllity and to some extent is a sales
feature.

     A total power requirement of 96 kW  (128 bhp) and a torque back-up of 20%
to enable the prototype vehicle to achieve Its target performance could be
achieved easily with a  3 Htre, six cylinder engine running up 83.3 rev/s.  A
typical oversquare cylinder configuration of 88 mm bore x 82 mm stroke (3,^6" x
3.22") has been selected.  The use of petrol  Injection will ensure good distribu-
tion between cylinders  and should allow the engine to run at generally leaner
mixture strength than If carburettors were used,  Estimated performance can be
seen In Fig. 2,

     These performance  figures and the project primary emissions targets could be
achieved using the same external hang-on control devices as the V-8 gasoline
engine, I.e. modulated  exhaust gas recycle, air  Injection and an oxidation
catalyst.

     Overall economy levels during CVS-CH testing have been predicted at 17.4
miles/U.S. gallon (13.5 L/100 km).  This results In a total fuel consumption
saving of some 7.5% compared with the V-8 gasoline engine.

     From European data, the predicted engine weight is 204 kg  (450 Ib), a
reduction of 41 kg (100 Ib) compared with the V»8 engine.

     Estimated drive-by noise levels of this engine in the prototype vehicle are
73 dBA at 15 m (50 ft).  The reason for the 2 dBA Increase in drive-by levels

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compared with the V-8 Is the higher rotational speed of the 3 litre engine,

     As with the V-8 engine, the secondary target could be achieved at  low mile-
age with reducing catalysts but current versions of these catalysts cannot
achieve adequate durability and so no configuration is given for  the secondary
target.
10

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                     ENGINE CONFIGURATION WITHIN CATEGORY I
     The Ford PROCO combustion system was chosen from the various systems within
Category 1  for application to the configuration study because It has already been
satisfactorily developed and utilised for automotive purposes.  In addition, the
hydrocarbon emission levels are tolerable, and can be easily controlled.   This
system has, therefore, a better known potential compared to the other systems of
which only  the M.C.P, has been developed to a stage suitable for possible
automotive  application.

     Turbocharged versions were not considered to give any useful advantages to
this category of stratified charge engine, and were, therefore, not included.
No rotary engines were Included since It  is believed that an early fuel  injection
timing would not provide satisfactory charge stratification during the period of
time before the Ignition point,  Furthermore, no experimental evidence could be
found to support the feasibility of a rotary version within this category.

     Engines Included In the configuration study and schemed to meet the primary
emission target were:-

(1)  V-8, O5 L, PROCO engine.

(2)  I-L 6, *4.15 L, PROCO engine.

     Only one engine configuration was considered feasible to achieve  the
secondary emission target:-

(3)  V-8, 5.25 L, PROCO engine

Category I

(1)  V-8 Naturally Aspirated - PROCO  Engine  -  Primary Emission Target
Bore

Stroke

Bore/Stroke Ratio

Displacement

Compression Ratio

Power

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max, Piston Speed

Max. Cylinder Pressure
87 mm

87 mm

1

M5 L

llil

96 kW
     at 66.7 rev/s
6.93 bar

8.9 bar
     at 38 rev/s
292 Nm
23,1 kW/L

11 .6 m/s

65.5 bar
3.^3 in

3,A3 In
    in3
128 bhp
       at AOOO rev/mln
100 Ibf/ln2

129 lbf/in2
       at 2280 rev/mln
215 Ibf.ft
0,501* bhp/ln-

2280 ft/mln

950 lbf/in2
                                                                                11

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Con-rod

Distance between centres, L          148.6 mm

Ratio of L to crank throw (r),   r   3.42
                                                           5.85 in
Cylinder bore  spacing

Package

Engine  length

       height

       width

       box volume

       weight

Predicted CVS-CH Results

Fuel Economy

Fuel Consumption

HC  )
CO )
     Baseline/Controlled
NO   Controlled
  x

Estimated noise
                                           1.17 x cylInder  bore



                                     770 mm                30.3  in

                                     597 mm                23,5  In

                                     600 mm                23.6  In

                                    .275 m3                9,72  ft:

                                     250 kg                550 Ib



                                     18.7 mlles/U.S. gallon

                                     12.5 L/100 km

                                     1.0/0.15 g/mlle

                                     8.0/1.0  g/mlle

                                     1.4      g/mlle

                                     71 dBA
Predicted Performance,  Economy, Emissions and Noise

     A total swept volume of 4.5  litre  (254 in ) was calculated using an estimated
bmep of 6.9 bar  (100  Ibf/ln ) at  the rated speed of 66.7 rev/s (4000 rev/mln),  to
yield 96 kw 028 bhp).

     The engine bmep  curve was estimated by predicting the Imep from the volumetric
and Indicated thermal efficiencies, and taking account of engine friction,
Knowledge of the performance of the proposed helical type of inlet ports provided
values of volumetric  efficiency and indicated thermal efficiencies were obtained
from published curves on PROCO engines-  The friction (fmep) losses of the Ford 7
litre FCP engine were used for these calculations and the resulting engine bmep Is
slightly above that for the Ford  Ll4l PROCO engine,  The estimated performance
curve of this engine  Is shown In  Fig, 3-

     To meet the primary NO  emission level of 1.5 g/mlle, an average of 1% of
the exhaust gas must  be reclrculated with proportional modulation, but reduced  to
zero flow at full load.  A large  oxidation catalyst will also be required for the
vehicle to achieve the primary emission levels of 0.41 g/mlle HC and 3-4 g/mlle
CO.  The catalyst position will be underneath the vehicle floor and must be placed
as close as possible  to the exhaust manifolds.  In order to generate high exhaust
gas temperatures following a cold start, the exhaust manifolds must have a low
12

-------
thermal Inertia, so that the catalyst  may light  off.

     Fuel  consumption and emission estimates  were  made  by  careful  extrapolation
of published data from tests on various PROCO engines.   Emissions  durability of
this vehicle Indicated that the primary target emissions should  be maintained  for
at least 25,000 miles.  The most critical emissions  durability factor  is  the HC
catalyst conversion efficiency required to hold  the  HC  result to below O.M g/mile.

     The test results recorded on the  PROCO Capri  by SWR1  were taken  into account
In making  the noise estimation,

Design Notes

     The choice of a bore/stroke ratio of 1 compared to a  bore/stroke  ratio of
1.29 on the Ford LlM engine was made  because a  smaller bore will  give better
combustion control and combustion efficiency. Moreover, a smaller bore will give
lower noise so the bore/stroke ratio of 1 is  therefore  a compromise with  adequate
breathing  and engine height.

     The engine Installation drawing (Fig, *•) shows  the important  engine  package
dimensions.  Cylinder centres at 1.17  x cylinder bore are  controlled  by the casting
core thickness of the water jacket between the bores,

Cylinder head and manifold arrangement

     Swirl type Inlet ports, fuel Injectors and  push rods  are  positioned  on the
Inboard side with the exhaust ports and spark plugs  on  the outboard  side,  The
cylinder head layout Is shown in Fig,  5-  Spark  plugs and  fuel  Injectors  are
retained by the use of screwed sleeves.

     The exhaust manifolds are placed  outboard to give  cross-flow  porting and  the
best cylinder head layout with four retaining cylinder  head studs  surrounding  each
bore.  The manifolds are then turned downwards from the cylinder ports and do  not
Increase the width of the engine significantly.

Combustion system and breathing considerations

     The combustion chamber which Is concentrically placed In  the  piston  crown Is
symmetrical about the vertical bore centreline.   The piston Is  designed to have
about 60%  squish area.  Fig. 5 shows the combustion chamber, spark plug and  fuel
Injector layout,  The spark plug and Injector relative  positions are  essentially
the same as used on the Ll^l PROCO engine so that the spark plug gap  is located
just above the conical spray of Injected fuel.

     In-cyllnder air swirl Is Imparted by means  of a helical type  of  swirl-
generating Inlet port, as Indicated In Fig. 5,  The PROCO  method of  imparting
swirl Is to use an Intake port having  a directed Intake restriction In the shape
of a crescent but helical Inlet ports  give a superior volumetric efficiency,   The
In-cyllnder swirl Is estimated to be 3 times the crankshaft speed.

     The Inlet valve Inner seat diameter Is 3^,6 mm, about kO%  of  the bore, which
gives a mean Inlet gas velocity of about 73,2 m/s (240  ft/sec)  at  the rated  speed.

Fuel Injector and control system

     The fuel Injector Is the outwardly opening  poppet  valve type  and Is  identical

                                                                                13

-------
 to  the  one  used  on the  Ford  PROCO  L141 engine.  The poppet valve is designed to
 vibrate at  2000-4000  Hz during  Injection  to  improve the fuel spray quality,   The
 valve opening  pressure  Is  17.24  bar.

     A  combined  Injection  pump and  Ignition distributor unit, again identical to
 that used on  the Ford PROCO  Ll4l engine,  has been utilised.  This unit Is
 positioned  In  front of  and at the  same angle to the vertical as the left  hand bank
 (see Fig. 4).  Because  of  the difficulty  of positioning this unit with a  suitable
 drive,  this was  considered to be the best compromise solution to give the shortest
 length  of fuel pipes  leading to  the  Inboard  Injectors.  The drive of this unit Is
 by  a mitre  bevel  gear off  the front end of the camshaft, for timing accuracy,

 Auxl1lary Drives

     The camshaft,  fuel  pump/distributor  unit and hydraulic pump are driven  by an
 Internal gear  system.  Gear  drives give good reliability and accuracy of  timing over
 long periods with low noise.

     Twin V-belt  drives are  used for the  alternator and water pump and a  single
V-belt  for  the air  conditioning  unit.  A  conventional skew gear drive Is  used for
 the ol1 pump.

 Category I

 (2)  In-line 6.  Naturally Aspirated - PROCO Engine - Primary Emission Target
Bore                                 96 mm

Stroke                               96 mm

Bore/Stroke Ratio                    1.0

Displacement                         **,15 L

Compression Ratio                    11 tl

Power

BMFP

Max. BMEP                            8.8 bar

Max. Torque                          293 Nm

Torque Back-up                       26%

Power/Unit Displacement              23.3 kW/L

Max. Piston Speed                    12 8 m/s

Max. Cylinder Pressure               65.5 bar

Con-rod

Distance between centres, L          152.4 mm
                               L/
Ratio of L to crank throw (r)»   r   3,17

14
                      3.78  In

                      3.78  in



                      254  in3



96.5 kW               129  bhp
       at 66.7 rev/s        at  4000  rev/mln
6.95 bar              101  1bf/in2

                      128  lbf/in2

                      216  Ibf.ft



                      0.508 bhp/in3

                      2520  ft/min

                      950  lbf/ln2



                      6.0  in

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Cylinder bore spacing                      1.1 7 x cylinder bore

Package

Engine length                        995 mm                39.16 in

       height                        638 mm                25.12 In

       width                         528 mm                20.8 in

       box volume                    .335 m                11.84 ft^

       weight                        263 kg                580 Ib

Predicted CVS-CH Results

Fuel Economy                         18.4 mlles/U.S. gallon

Fuel Consumption                     12.74 L/100 km

HC )                                 1.0/0.15 g/mlle
   ) Baseline/Controlled
CO )                                 8.0/0.8  g/mlle

NO  Controlled                       l.3g/mile
  /\

Estimated noise                      75 dBA

Predicted Performance. Economy, Emissions, and Noise

     The specification for a target power output of 96 kW (128 bhp) was met by an
In-line 6 cylinder engine of 4.15 litre (254  In').  The method of performance
calculation used for the previous PROCO V-8 configuration was applied and the
estimated performance curve of this engine Is shown In Fig, 7.  Fuel consumption,
exhaust emission and noise predictions were also made, using the previous methods.

     The same exhaust emission control methods as proposed for the V-8 configuration
will be necessary.  That Is, an average rate of 1% EGR with proportional mod-
ulation,  reducing to-zero flow at full load, plus a single oxidising catalyst
fTtted Into the exhaust system underneath the vehicle floor,  Emissions durability
should be satisfactory to hold the exhaust emission levels to within the primary
target for at least 25,000 miles.

Design Notes (Figs. 8, 9)

     The bore/stroke ratio of 1 was chosen, common to the V-8 configuration and
for the same reasons.

     The engine Installation drawing (Fig, 8)  shows the Important engine package
dimensions and a cross-sectional arrangement of this engine Is shown In Fig. 9,
Cylinder centres at 1.17 x cylinder bore controlled by casting core thickness of
the water jacket between bores.

Cylinder Head and Manifold Arrangement

     Cylinder head layout as for previous  V*8  configuration.  Cross-flow porting
gives more latitude to the porting,  spark  plug and Injector layout than a unl-sided

                                                                               15

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port arrangement.  An air  throttle  is used to control the inlet air quantity during
part load operation.

Combustion system  and breathing considerations

     The layout of the  Injector, spark plug and valves in relation to the com-
bustion chamber Is practically  identical to the previous V-8 configuration.
Helical Inlet ports are  used  to impart the In-cyltnder air swirl.

     The Inlet valve  Inner  seat diameter Is 39.8 mm, 41.5% of the  bore,  which
gives a mean  Inlet gas velocity of  80 m/s at the rated speed.  Although  this high
velocity penalises the breathing at high speeds, the target power  is met and torque
back-up fs excellent,

Fuel Injector and  Control  System

     The same fuel Injector and a similar fuel pump/distributor unit as  described
for the previous V-8 configuration  has been schemed for  this engine.  The fuel
pump/distributor unit is mounted in a vertical position  at the front of  the  engine
and driven by a mitre bevel gear from the end of the camshaft for  accuracy of
t Iminei.

Auxl1lary Drives

     An Internal gear system  Is used to drive the camshaft, fuel  pump/distributor
unit and hydraulic pump.  Twin V-belt drives are used for the alternator and water
pump and a single  V-belt drive for  the air conditioning  unit.  All the above
auxiliaries are mounted  on  the front of the engine as indicated in Fig-  8

Category 1  .

(3)  V-8 Naturally Aspirated  - PROCO Engine - Secondary  Emission  Target
Bore

Stroke

Bore/Stroke Ratio

Displacement

Compression Ratio

Power

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max. Piston Speed
9  mm

9*» mm

1.0

5.25 t

11:1

122 kW
      at 66.7 rev/s
7 bar

8.8 bar

365 Nm

13*

23.A kW/L

12.6 m/s
3.7 in

3.7 in



320 in:
163 bhp
       at AOOO rev/min
101 5 Ibf/in2

128 lbf/in2

270 Ibf.ft
0.509 bhp/ln'

2*470 ft/min
16

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Max.  Cylinder Pressure               65.5 bar              950 lbf/in2

Con-rod

Distance between centres, L          162.6 mm              6.** in
                               L/
Ratio of L to crank throw (r),   r   3.^5

Cylinder bore spacing                     1.17 x cylinder bore

Package

Engine length                        800 mm                31.5 in

       height                        609 mm                2k in

       width                         622 mm                2^.5 In
                                            3                     ^
       box volume                    0.303 m               10.7 ft

       weight                        259 kg                570 Ib

Predicted CVS-CH Results

Fuel  Economy                         16.5 miles/U.S. gallon

Fuel  Consumption                     1^.2 L/100 km

HC )                                  2.5/0.25 g/mile
   )  Baseline/Controlled
CO )                                  12.0/0.8 g/mile

NO   Controlled                      0.37 g/mile

Estimated Noise                      72-5 dBA

Predicted Performance. Economy, Emissions and Noise

     In order to offset the power loss due to the extra EGR quantities and so
maintain satisfactory vehicle propulsion during the CVS-CH driving cycle, an
increased engine swept volume over that proposed for the primary emission target
engines will  be required.  Computer calculations Indicated that an engine swept
volume of 5.25 litre (320 in3) would be sufficient for this purpose.

     The BMEP developed by the engine when operating with the high EGR rates
during the CVS-CH driving cycle was assumed to be between k,8 and 5.8 bar
(70-85 lbf/in2) depending on speed, based on Ford's published figures from their
Ll^l  PROCO engine.  The engine capacity of 5.25 litre ensures that the maximum
BMEP  of 5.8 bar should not be exceeded during the CVS-CH driving cycle.  Predictions
of the engine full throttle performance were made using the same method as described
for the V-8 primary emission target engine and the estimated performance curve is
shown in Fig. 10.  It is clear that since the EGR Is modulated to zero rate at full
load, the maximum power is well above the target of 96 kW, at 125 kW and therefore
road  performance will be more than adequate.
     To meet  the stringent secondary NO  emission target of 0.^ g/mile higher EGR
                                       X
                                                                                 17

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 rates of about  20-25%  at  light  loads modulated to  \5% at the maximum CVS test  loads,
 These EGR  rates will  increase the  engine HC emissions such that a single catalyst
 would not  give  a  satisfactory durability.

     Two oxidation  catalysts, fitted in series, underneath the vehicle floor,  is
 considered  to be  the most  convenient method to control the HC and CO emissions.
 Low thermal  inertia exhaust manifolds will also be necessary.  Emission durability
 to meet the  secondary  emission  target levels of 25,000 miles driving, cannot be
assured at  the  present moment,  but should be possible after further catalyst and
engine development.

Design Notes

     The necessary  engine  swept volume of 5.25 litre was best met with a- V-8
engine configuration.

     The same reasoning was used in the determination of a bore/stroke ratio of
unity as was applied to the earlier configurations within this category.  In other
words, the minimum  bore size compatible with the combustion system was chosen to
give good combustion control.

     The cylinder head and general  engine layout Is basically identical but
proportionally  increased  in size to that used for the V-8 configuration schemed  to
meet the primary emission  target.   For this reason only the installation drawing,
Fig. 11, has been Included to allow an assessment of the engine configuration.

     Auxiliary  drive systems and installation positions also follow those proposed
for the previous V-8 configuration.
 18

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                      ENGINE CONFIGURATIONS WITHIN CATEGORY 2
     The Texaco TCCS has undergone a considerable development programme for
automotive applications and was therefore chosen for this configuration study.
Deutz have a system with a similar arrangement to Texaco but not developed so
extensively, whilst Curtfss-WrIght have applied their system to a rotary engine.
A rotary engine with the Curt Iss-Wrlght system has also been configurated.

     To meet the primary emission target, three engine builds have been schemed:-

(1)   V-8, 5.4 L Naturally Aspirated, TCCS engine.

(2)   1-L 6, A.16 L, Turbocharged, TCCS engine.

(3)  . Rotary, 2 bank, 5-5 L, Curtiss-Wrlght engine.

     Only one engine has been schemed to meet the secondary emission target:;

(4)   V-8, 5.87 L, Turbocharged, TCCS engine.

Category 2

(1)   V-8 Naturally Aspirated - TCCS Engine - Primary Emission Target
Bore

Stroke

Bore/Stroke Ratio

Displacement

Compression Ratio

Power

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max. Piston Speed

Max. Cylinder Pressure

Con- rod

Distance between centres, L
                              i/
Ratio of L to crank throw (r)   r

Cylinder bore spacing
                                     95 mm

                                     95 mm

                                     1.0

                                     5.4 L

                                     10:1

                                     96 kW
                                          at 66.7  rev/s
                                     5.3 bar

                                     6.5 bar
                                          at 29  rev/s
                                     280 Nm

                                     23%

                                     17.8 kW/L

                                     12.7 m/s

                                     51.4 bar
                                      162.6 mm

                                      3.41

                                            1.23 x cylinder bore
3-74 in

3-74 in



330 in3
128 bhp
       at 4000 rev/min
77 Ibf/in2

94 lbf/in2
       at 1740 rev/min
206 Ibf.ft
0.388 bhp/ln:

2500 ft/mln

745 lbf/ln2
6.4 in
                                                                                19

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 Package

 Engine  length                         823 mm                32.k in

       height                         658 mm                25.9 in

       width                          622 mm                2^.5 in
                                             •>                     •?
       box  volume                     0.337 m               11.9 ft

       weight                         273 kg                600 Ib

 Predicted CVS-CH Results

 Fuel Economy                          17 miles/U.S. gallon

 Fuel Consumption                      13.8 L/100 km

 HC  )                                  2.5/0.3 g/mlle
    ) Baseline/Controlled
 CO  )                                  10/1-5 g/mile

 NO   Controlled                       0.8 g/mile
  />

 Estimated Noise                       70.5 dBA

 Predicted Performance.  Economy.  Emissions and Noise

     The relatively  low bmep characteristic of this engine required a large engine
 swept volume of 5.^t  litre  (330  in3)  in order to achieve the target power output,
 96 kW (128 bhp) at 67 rev/s  (*»000  rev/min).  An In-Hne 6, naturally aspirated
 version was not considered to be attractive, due to high piston speeds.

     Performance calculations were made using the following method.  The maximum
 power air/fuel ratio and indicated specific fuel consumption for the TCCS process
 had first to be established.  Since  the TCCS process is smoke limited, the maximum
 power air/fuel ratio Is a function of the engine smoke level.  Information
 extracted from reports  by Texaco and  Toyota on the L]k] engine is shown in Fig. 12.
 Apparently, the Toyota  engine reached a Bosch No. 4 smoke limit at a leaner air/
 fuel ratio than the Texaco engine.  Therefore, the power output was lower.  At a
 Bosch smoke number of 2-2i, which  is  realistic for automotive applications, the
 power output of the Texaco engine was reduced by about 10%.  Presumably the per_
 formance of the Toyota  engine would be compromised by a similar factor at this
 smoke level.  However,  It was decided that the more optimistic Texaco results should
 be used for this prediction

     Indicated specific air consumption was calculated from air/fuel ratios multi-
 plied by Indicated specific fuel consumption, Fig. 13, and extrapolated to 1000 and
 4000 rev/min.   The volumetric efficiency was estimated by calculation of the gulp
 factor.   Unity gulp factor was  found  to be at 5000 rev/min.  A correlation exists
 in Taylor and Taylor (The Internal Combustion Engine, publisher International
 Textbook Company) between gulp  factor and volumetric efficiency, so these values
were extracted and Increased by 2%.  The values in Taylor and Taylor refer to a
 gasoline engine, and If fuel Is absent from the induced air, the volume occupied by
 the fuel  vapour can be  replaced by air.  Engine power was then calculated from:-
20

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               IMEP    =  	Volumetric efficiency	
                          Indicated specific air consumption

     Next, the friction levels of three Ll^l engines were inspected, Fig. !*».  At
2500 rev/mln and 3000 rev/min the FMEP was lower than for a typical  European k
cylinder gasoline engine.  This was surprising, In view of the additional motoring
loss of the fuel  Injection equipment.  However, the late closing of the inlet valve
of the LlAl and the low volumetric efficiency at higher speeds may result in a
lower effective compression ratio.  This would reduce the compression expansion
motoring loss.  In the predicted engine, the inlet valve opening period has been
reduced, so one would expect the friction levels to be similar to the typical k
cylinder engine.   Thus, the BMEP of the predicted engine was calculated from the
IMEP above, and the average friction levels of the Ll*»l engines.

     The resulting performance curves for this engine are shown in Fig. 15, and the
target power of % kW (128 bhp) is reached at 66.7 rev/s.  It Is clear that the
specific power output of this engine Is low at 17.8 kW/litre  (.39 bhp/in3) due to
the lean operating air/fuel ratio, at the smoke limit of Bosch No. 2?-]?.

     This category of stratified charge engine inherently gives high baseline HC
emissions and for this reason there will be a high dependence on oxidising
catalysts in order to achieve the HC primary emission target of 0.41 g/mile.  It is
considered that for all engine configurations within this category, two catalysts,
connected In series, will be necessary to control the HC emissions.  This catalyst
arrangement will  automatically control the CO emissions satisfactorily.  Ricardo
did not propose a thermal reactor plus an oxidising catalyst, as Texaco have done
to achieve the secondary target, since it is considered less economic to produce
two different exhaust control components.

     The exhaust pipe from each engine bank will require it to be joined as close
to-the engine as Is conveniently possible to allow an early entry into the first
catalyst.  Low thermal inertia exhaust manifolds, preferably  Insulated, will also
be necessary to avoid exhaust gas temperature  losses.

     A level of about 10? EGR modulated during the light to medium loads of the
CVS-CH driving cycle  Is recommended.  This  relatively high EGR rate will reduce
the NO  emission more than necessary but  is considered as the best method of in-
creasing the exhaust gas temperature for catalyst operation.  EGR should be mod-
ulated to zero rate at full load.

     It is thought that there may be problems  In maintaining the HC levels to
within the primary target of 0.1*1 g/mile.  However, with the  large volume of two
catalysts the target emission levels should be held for a period of 25,000 miles.
A good NO  emission durability should result and no problems  in meeting the NO
emission target for 50,000 mile periods are envisaged.

Design Notes (Figs. 16. 17. 18)

     This engine was designed in a conservative manner following many stipulated
procedures set down by Texaco for guidance related to engines having the TCCS com-
bustion system.

     Having calculated the engine swept volume of 5-*» litre (330 in ), the
mathematical procedures prescribed by Texaco were employed to optimise the bore/
stroke ratio to 1  and compression ratio to 10:1.
                                                                                21

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      The  cylinder centres  at  1.23 x cylinder  bore are wider than standard American
 gasoline  engine practice.   The  wide cylinder  spacing was found necessary in order
 to allow  sufficient space  for  the necessary porting and combustion system layout.
 A penalty In  extra engine  length  results.

      The  engine Installation drawing,  Fig. 16, shows the important engine package
 dimensions.   Fig,  17 shows the  cylinder  head  layout and Fig. 18 is a cross-
 sectional  arrangement.

 Cylinder  Head and Manifold Arrangement

      The  porting  layout  of the  TCCS combustion system employing high swirl  inlet
 ports was  best achieved  with a  cross-flow arrangement.

      Five  retaining cylinder head studs  surrounding each bore were found to give
 the greatest  design scope  for  the porting layout.  Fuel injectors and spark plugs
 were  on the outboard (exhaust)  side and  pushrods on the inboard side.

 Combustion System and Breathing Considerations

      The  TCCS combustion system was employed  which comprises a toroidal  type,
 deep  bowl  combustion chamber in the piston.   The piston bowl diameter, being 58%
 of the bore,  was  designed  to give Texaco swirl levels of 3-5 x engine speed and
 7.5 x engine  speed at the  end of  Induction and at t.d.c. respectively.

      The  fuel  injector and spark  plug  positions follow close.ly those recommended
 by Texaco  such that the  spark plug gap  is on  the edge of the fuel spray, as can be
 seen  in Fig.  17-   A special  ignition system,  the Texaco Transistorised Ignition
 system, provides  a high  energy  and long  duration spark.  Furthermore, the spark
 plug  is sleeve mounted into the cylinder head at a pre-determlned radial position
 to ensure  that  Its earth electrode does  not Interfere with the fuel spray directed
 towards the Ignition source.

      High  swirl  inlet ports specially  developed by Ricardo have been utilised in
 place of  the  Inlet ports stipulated by Texaco.  The Ricardo Inlet ports should
 give  improved volumetric efficiency and  performance, In particular at high speeds.
 In other  respects  the Texaco recommendations  on inlet valve dimensions and timing
were  follows.

                Valve lift/Inner seat diameter            28%

                Inner seat  diameter/cylinder bore          38.5%

                Inlet valve opening period                 232°

     The  Inlet  valve Inner seat diameter of 36.6 mm gives a mean inlet gas speed
of 68.8 m/s (226  ft/sec) at the rated  speed of 67 rev/s.  A high valve offset of
 13 mm from the  cylinder  bore centre has  been  employed in order to make space for
 the spark  plug  and fuel  Injector  layout.

 Fuel   Injector and  Control  System

     The fuel   Injector Is  of the  inward  opening pintle type but with a flat
 pintle sealing  face  as developed  specifically for the TCCS system by Texaco.  A
distributor type of  fuel injection pump, again as used by Texaco, has been mounted
 between the cylinder  banks  and  Is  gear driven from the front of the crankshaft.


 22

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The fuel  pipes are unavoidably long due to the position of the outboard Injectors.

Auxi1lary Drives

     The camshaft, fuel  Injection pump and Ignition distributor are gear driven
from the front of the crankshaft, the Ignition distributor having a separate skew
gear drive from the gear on the camshaft nose.  Gear drives were chosen for
accuracy of timing over  long periods combined with reliability and low noise.  A
conventional skew gear driven oil pump is used.

     Twin V-belts drive  the alternator, water pump and hydraulic pump and a single
V-belt drives the air conditioning unit.  Fig. 16 shows the Installation layout
of the above auxi1 tarles.

Category 2

(2)  In-Llne 6, Turbocharged - TCCS  Engine - Primary Emissions Target
Bore

Stroke

Bore/Stroke Ratio

Displacement

Compression Ratio

Power

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max. Piston Speed

Max. Cylinder Pressure

Con-rod

Distance between centres,  L

Ratio of L to crank  throw  (r),

Cylinder bore spacing

Package

Engine length
96 mm

96 mm

1.0

It. 16 L

9:1

96 kW
     at 66.7 rev/s
6.9 bar

9.0 bar
     at *42 rev/s
298 Mm
23.1 kW/L

2520 m/s

71 bar
3.78 in

3.78 in



251* In3
128 bhp
       at ^000 rev/min
100 lbf/ln2

130 lbf/in2
       at 2500 rev/min
210 Ibf.ft
151.1 mm

3.15

       1.16 x cylinder bore
0.50A bhp/in

12.8 ft/min

1030 lbf/in2



5.95 in
                                  3
981 mm
38.62  in
                                                                                 23

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        height                         610 mm                24.0 in

        width                          578 mm                22.76 in

        box  volume                     0.346 m               12.2 ft

        weight                         260 kg                572 Ib

Predicted CVS-CH Results

Fuel Economy                          17miles/U.S. gallon

Fuel Consumption                      13.8 L/100 km

HC )                                  2.0/0.22 g/mile
   ) Baseline/Controlled
CO )                                  10/1.5 g/mile

NO   Controlled                       0.8 g/mile
  J\

Estimated Noise                       71 dBA

Predicted Performance,  Economy,  Emissions and Noise

     This turbocharged  engine was  schemed to evaluate a power plant with a higher
specific power output than  the previous naturally aspirated version.  As a result
of turbocharglng the engine swept  volume required to achieve the same target pei—
formance level is  reduced from 5-4 litre (330 in3) for the NA version to 4.16
litre  (254  In3).

     A  target of 8.95 bar BMEP at  2000 rev/mln was adopted as the starting point
from which  performance  calculations were made.  This condition implies a boost
density ratio of 1.27.  A typical  compressor curve was obtained from a turbocharger
manufacturer, and  an empirical Ricardo relationship between boost pressure and
engine  speed used  to predict the boost density ratio over the remainder of the
engine  speed range, Fig. 19.

     The fuel pump discharge characteristics had to be tailored to prevent over-
loading the engine structure.  A simple formula was derived for the maximum
cylinder pressure  based on  the constant volume cycle, where the values of the ratio
of specific heats  for the gas were based on polynomials of gas temperature and
mixture strength.  Air/fuel ratios were calculated for each engine speed above
2000 rev/mln (also shown in Fig. 19), assuming that the maximum cylinder pressure
did not exceed that at  2000 rev/min.  These calculations Indicated that the fuel
delivery per injection  should decrease by 33% in a linear manner between 2000 and
4000 rev/mln.  Fuel Injection pumps do not follow this trend naturally, so a speed
modulated cut-off  device would be  required.  An air/fuel ratio of 19:1 at 2000
rev/min, corresponding  to Bosch  smoke No. 2, was maintained.  During engine
accelerations, the finite response time of the turbocharger could cause the air/fuel
ratio to drop below 19:1, and the  engine would emit a higher smoke level.

     L141   engine  results were cross-plotted as indicated specific fuel consumption
against air/fuel ratio, and this relationship was assumed to be applicable to the
turbocharged version, see Fig. 20.  Next, the appropriate fuel  consumption was
obtained at the air/fuel ratio corresponding to each engine speed.   Finally, IMEP
was calculated by  the following  formula:-


 24

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              	Density Ratio x Volumetric Efficiency
           ~~  Air Fuel Ratio x Indicated Specific  Fuel  Consumption

     The friction levels of a typical European gasoline engine were  used  to
calculate the brake performance curves shown in Fig.  21.   This was an  optimistic
friction figure, since the maximum cylinder pressures were calculated  to  be  about
\5% above standard European gasoline engine practice, and about 30?  above U.S.
gasoline engine practice.

     Specific engine power at 23.6 kW/litre (.5'5  bhp/In ) is significantly
improved by comparison to the previous naturally aspirated engine together with
a lower estimated engine weight of 260 kg (572 Ib).

     There fs a high dependence on oxidising catalysts to reduce the HC emissions
to the primary target of 0.^1 g/mile.  Two catalysts  fitted in series, downstream
of the turbocharger, will be necessary.  The exhaust  manifold is recommended to be
of fairly large volume,  Insulated and with a low thermal  Inertia.  This type of
exhaust manifold should  reduce exhaust gas heat losses and so assist the catalyst
oxidation efficiency.  The CO emissions should be automatically controlled with the
above exhaust system.

     A 10% rate of EGR is recommended during the light to medium loads encountered
during the CVS-CH test cycle in order to maintain sufficiently high exhaust
temperatures for catalyst operation,  the EGR rate being modulated to zero rate at
full load.  The NO  emissions should  be adequately low with these EGR rates.

     The catalytic problem of maintaining the HC emissions to within the primary
target will be the critical emission  durability factor, as for the previous  con-
figuration.  However, there should be no problems in maintaining the CO and  NO
emission to within the respective target levels for a 25,000 mile period.

Design Notes (Figs. 22.  23, 2k)

     This engine was designed to be  highly  boosted by turbocharging, resulting in
higher cylinder pressures than normally associated with gasoline engines and the
crankshaft was therefore made more rigid to cope with the higher loadings.  Cylinder
spacing at 1.16 x cylinder bore was  controlled by the casting core thickness of the
water jacket between bores.

     It should be noted  that the air  filter has not  been  included in the engine
package size since in this case It would be more conveniently mounted on the vehicle
than on the engine.  Fig. 22 shows the  important engine package dimensions.

Cylinder Head and Manifold Arrangement

     The fitting of a turbocharger made a uni-sided porting arrangement  the most
convenient.  High swirl  (helical) Inlet ports are employed with a four stud
cylinder head pattern as the best solution  for the porting layout.  This also allows
more compact cylinder spacing than the previous TCCS V-8.  Pushrods are on  the
manifold side and spark  plugs plus  Injectors on the other side.  The  Injectors are
mounted with single bolt clamps and  the spark plugs with screwed sleeves.

Combustion System and Breathing Considerations

     The TCCS combustion system was  employed as shown in Fig. 23.  Combustion
chamber and valve proportions are substantially the same as recommended  for the

                                                                                  25

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 naturally aspirated engine, as  is  the  Ignition system.  The fuel  injector and
 spark plug  specification and  relative  positions are also the same.

     The compression  ratio  is reduced  from the naturally aspirated  version to  9:1.
 The high swirl  inlet  ports might  Increase the swirl levels with pressure boosting
 but these should  still  lie within  the  swirl levels stipulated by Texaco of 7 to 10
 times engine  speed at  t.d.c.  An alternative to this approach would be to reduce
 the Inlet valve diameter and  increase  the exhaust valve diameter.   The swirl level
would be reduced  to about 7,  but additional turbine boost could be  achieved from
 the higher  kinetic energy of  the exhaust gas.  This approach could  improve the
 transient characteristics of  the  turbocharger, but involves a difficult matching
operation and exhaust  manifold  layout.

 Fuel Injector and Control System

     Fuel Injectors were  identical  to  those for the naturally aspirated engine.
A 6-cyl!nder  version  of the distributor type fuel injection pump is mounted
horizontally  on the opposite  side  to the manifolds in a position to give the
 shortest possible fuel  pipe lengths.

Auxl1lary Drives

     An  internal  gear drive system is  used to drive the camshaft,  fuel Injection
pump and hydraulic pump.  Conventional skew gear drives are used for the Ignition
distributor and oil pump.  Vee-belt drives are used for the alternator, water
pump and air  conditioning unit.   Fig.  22 shows the Installation layout of the above
auxi1larles.

Category 2

 (3)  Rotary,  2  Bank - Curtiss-Wright Engine - Primary Emission Target
Generating Radius
Rotor Width
Eccentricity
Displacement
Compression Ratio
Power
BMEP
Max. BMEP
Max. Torque
Torque Back-up
Power/Unit Displacement
Max. Cylinder Pressure
122 mm
79 mm
18.1* mm
5.5.L
8.5:1
97 kW
at 83 rev/s
6.3 bar
7.4 bar
at 56 rev/s
214 Nm
17.4%
17-6 kW/L
42 bar
4.8 in
3.11 in
0.724 in
336 in3

130 bhp
at :
91.5 lbf/ii
107 Ibf/in
at
158 Ibf.ft

0.387 bhp/
609 Ibf/in
                                                                  at 5000 rev/min
                                                                     n2
                                                                  at 3360 rev/min
                                                                     .  3
26

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Package

Engine length                        523 mm                20.6 in

       height                        660 mm                26.0 in

       width                         695 mm                27-35 in

       box volume                    0.2*» m                8.5 ft

       weight                        150 kg                330 Ib

Predicted CVS-CH Results

Fuel  Economy                         H.O miles/U.S. gallon

Fuel  Consumption                     16.?A L/100 km

HC )                                  3-0/0.3 g/mile
   )  Baseline/Controlled
CO )                                  15-0/0.8 g/mile

NO   Control led                      1.0 g/mile
  J\

Estimated noise                      71.0 dBA

Predicted Performance. Economy. Emissions and Noise

     Performance calculations were based.on results obtained by Curtiss-Wright to
predict that  a swept volume of 5-5 litre (336 in3), the swept volume being a total
of all  rotor  lobes,  would be required In order to achieve -the required target
performance.

     The  brake performance of this engine  is ultimately limited by smoke emission,
however,  Curt Iss-WrIght have not included smoke levels with their published power
curves.   For  this reason Ricardo limited the maximum bhp at each engine speed to
the smoke limits of  Bosch No. 2.5 at 25 rev/s (1500 rev/min) to Bosch No. 1.5 at
the rated speed of 83 rev/s  (5000 rev/min).  To make these calculations possible,
the ratio of  smoke limited bhp divided by the bhp at the maximum economy point as
calculated for I.D.I, diesel engines, was assumed to hold true for this engine.
Applying  the  smoke performance controlling factor to the published power output,
throughout the engine speed range of the Curtiss-Wrlght RC2-60U10 engine, enabled
the performance prediction to be made directly, see Fig. 25.

     The  engine specific power output, in terms of engine weight, is excellent
compared  with the naturally aspirated V-8 TCCS engine since the engine weight is
estimated at  just 150 kg (330 Ib).   Package size is also relatively small in
terms of  volume.

     It is worth noting that if the lobe sealing technology can be improved, a
better economy than  that estimated could be achieved.

     This engine version will produce higher baseline HC emissions, than the
previous  TCCS configurations considered within category 2 and because of the low
exhaust gas temperatures It will  be difficult to control both the HC and CO
emissions using catalysts without a specialised exhaust manifolding from the engine,


                                                                                27

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The exhaust manifold must  have a  low  thermal  Inertia and also be very well  in-
sulated  throughout  its  length  in  order  to maintain the exhaust temperature  high
enough for catalyst operation.  The compact exhaust porting and close fitted
manifold and also  the  inherent Inefficiency (i.e. internal EGR due to seal  leakages)
will help  In this  respect.  Two oxidation catalysts will be needed, fitted  In
series and as  close as  possible to the  exit from the exhaust manifold.

     There is  a  high dependence on the  catalysts to reduce the HC and CO emissions,
particularly the former emission, and maintaining the primary emission target for
a 25,000 mile  period may prove difficult.  No problems are envisaged In keeping to
within the NO  target of 1.5 g/mile and the addition of EGR is not necessary.
             J\

Design Notes

     Design features follow conventional ^-stroke form having two-lobe epitrochoid
chambers and three-lobe rotors.   The basic engine construction was based on Wankel
rotary combustion engine practice.

     The Installation drawing, Fig. 26  indicates the important engine package
dimensions and the Cross and Longitudinal sectional drawings on Fig. 27 show
details of the engine construction and  combustion system layout.

Manifold Arrangement

     The exhaust manifold  is bolted directly to the rotor housing, has low  thermal
Inertia and is well insulated to  maintain high exhaust gas temperatures.  The Inlet
manifold is mounted directly above the  exhaust manifold to suit peripheral
(radial) ports.

Combustion System and Breathing Considerations

     The shape of the combustion  chamber recess within each rotor flank follows
closely that proposed by Curtiss-Wright.  In plan view the recess is asymmetrical,
there being a  leading edge pocket on each side of the rotor.  This type of  recess
is known as a  "beetle"  type.  In  a section view the leading pockets of the  recess
are deeper than  at the  trailing edge  in-order to achieve the required time
distribution of  air mass past the fixed fuel spray envelope.

     Two pairs of closely coupled spark.plugs and fuel injectors per rotor  are
recommended.    This arrangement should give thorough mixing and consistent firing
properties which will result in the best possible air utilisation.  This is normally
the critical  aspect of  the stratified charge rotary engine.

     The location of the injector/spark plug intersection point Is 16.5° to the
epitrochoid minor axis  in the opposite direction to rotor rotation.  The included
angle between  each injector and spark plug Is *»0° with Injectors in the trailing
position.

     The spark plugs have a high heat range and conventional Wankel type electrodes.
They are sleeve mounted into the  rotor housing.  The Ignition system produces long
duration and high energy sparks and the distributor contains two rotors, each rotor
supplying the  pair of spark plugs for a rotor bank.

     The cavity  into which both the electrodes and nozzle tip protrude has  been
designed for minimum lost volume.   Furthermore, the combined width of two cavities
per rotor has  been kept small  to prevent excessive by-pass leakage around the apex
seals.

28

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     Peripheral  (radial)  inlet  ports  were preferred  to  side  (axial)  inlet  ports
due to the  comparative  gains  in volumetric efficiency.   Performance  will not  be
lost at low speed/low power conditions  by the  normal  effects  of  valve overlap
since fuel  injection occurs after the intake port  closes.

     The intake  port was  designed to  close at  80°  BTDC  (rotor) and exhaust port  to
open at 72° ATDC  (rotor).  These timings  were  fixed  as  design parameters for  sat-
isfactory running.  The other end timings were arranged for  a minimum valve over-
lap period  by making the  ports  narrow In  the rotational sense.

     Intake and  exhaust ports are split into two passages  within the rotor housing
by a bridge piece giving  column strength  to the rotor housing.   Each individual
port passage within the housing also  reduces in area by about 20% In a  direction
towards the engine  In the interests of  stable  flow characteristics.

Fuel Injector and Control  System

     The fuel  Injector  nozzles  are flush  mounted,  the  injection  spray pattern
having multi sprays with  a restricted angle (shower head type)  to prevent  spray
Interference between the  two  adjacent injectors.  A distributor  type of injection
pump injects Into two fuel  lines, each  line is then divided  for  connection to the
two injectors per bank.

     Dual injectors per rotor bank were chosen  so as to ensure  satisfactory  torque
output through  the  speed  range.

Auxi1lary Drives

     Fig. 26 shows  the  Installation  layout of  the auxiliaries.   Fuel injection
pump and ignition  distributor are conveniently  positioned close  to  the combustion
chamber. Both these  units are driven by a toothed belt tensioned by a jockey
pulley.  Toothed belts  are light,  inexpensive,  accurate and  quiet.

     The alternator and water pump are driven  by  twin  V belts and the air  con-
ditioning unit  by  a single V belt.  All  the above drive systems  are taken  from  the
front of the engine.

     The oil pump  is  driven by an  internal gear system, the  final drive also used
to drive the hydraulic  pump which  is external  to  the engine.

Detail Points

Eccentric Shaft  Bearings  - Bearing loadings were  calculated  to  cover gas  loads
only.  The  loading  of  the bearing.at the eccentric shaft/end  rotor  housing was
calculated  at  373  bar  (5^*00  Ibs/in2)  as  being  equivalent  to  the  maximum loading
with one bank  firing  neglecting  the  small effect  of  the second  non-firing  bank.
Bearing pressure of the eccentric  shaft/rotor  was 2^8  bar (3600  lbs/in2).

Conventional thin-walled  bearing  liners  are proposed for  the  latter bearings.   An
intermediate bearing  within the  dividing  rotor housing was considered  unnecessary
because of  the high stiffness of  the eccentric shaft.

Rotor- Material:  cast  iron for  good hot  strength and  low thermal expansion.  I-beam
type internal  structure with thin  internal  ribs gives  only a small  sacrifice of
weight  In comparison  to aluminium.   Oil  cooled.
                                                                                29

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Apex seals - Designed like an I-beam (material containing about 50X C and 50? Al)
so gases can activate the seal laterally instantaneously and so reduce the time lag
for good sealing.  There is normally a time lag between the increase in the com-
bustion chamber gas pressure and the gas pressure under the apex seal.  It is
thought that this will result In less 'chatter', higher combustion pressures,
lower fuel consumption and lower emissions than the conventional design of seals.

Oil is metered into the combustion chambers, to aid sealing, by its addition into
the gasoline at the fuel injection pump.  This oil should be ash-free to prevent
catalyst poisoning and minimise engine deposits.

Rotor Housing - Aluminium casting with chromium plated epitrochoid surfaces for
optimum wear and sealing properties with apex seals.
Rotor housing assembly is rigidly constrained by
housings are also aluminium castings.

Water Circuit
                                                 15 through bolts.   Rotor end
     The Water pump  is mounted on the front rotor housing discharging coolant into
the multi-pass axial flow coolant system.  The multi-pass forced coolant flow Is
matched to the circumferential variation of heat input, the initial  cold water
passes are adjacent  to the hottest  regions, i.e. coincident to the firing/expansion
rotor position.

     The internal ribbing structure of the rotor housings through which the coolant
flows, I.e. the ties between  the  inner and outer shells, are also mul ti -di rectional
to reduce thermal distortions and over-stressing of the trochoid surface.

Category 2

     V-8, Turbocharged - TCCS Engine - Secondary Emission Target
lore 101 mm
Itroke 92 mm
lore/Stroke Ratio 1.087
lisplacement 5-87 L
iompression Ratio 9:1
3.96 in
3. 6*1 in

358 in3

Power

BMEP

Max. BMEP

Max. Torque

Torque Back-up

Power/Unit Displacement

Max. Piston Speed
                                      135 kW
                                           at 66.7 rev/s
                                      6.9 bar

                                      9.0 bar
                                           at k\ rev/s
                                         Nm
                                      19*

                                      23.0 kW/L

                                      12.3 m/s
181  bhp
       at 1*000 rev/min
100  Ibf/in

131  Ibf/in2
       at 2^50 rev/mln
312  Ibf.ft
0.506 bhp/in'

2^30 ft/min
30

-------
Max. Cylinder Pressure

Con-rod

Distance between centres, L
                               L,
Ratio of L to crank throw (r),   r

Cylinder bore spacing

Package

Engine length

       height

       width

       box vo1ume

       weight

Predicted CVS-CH Results

Fuel Economy

Fuel Consumption
71  bar
152.14 mm

3-3

       1.2 x cy11nder bore
1030 lbf/in2
6 i n
HC )
   ) Baseline/Controlled
CO )
NO   Controlled
  /\

Estimated  Noise
845

645 mm

630 mm

0.343 m3

286 kg



14 miles/U.S. gallon

16.Ik L/100 km

4.5/0.25 g/mile

12.0/1.0 g/mile

0.33 g/mile

72.5 dBA
33-3 in

25.4 in

24.8 in

12.1 ft:

630 Ib
Predicted  Performance.  Economy, Emissions and Noise

     If a  naturally aspirated TCCS engine were to meet the secondary NO  emission
•target  of  0.4  g/mlle with EGR and combustion retard, then an engine swept volume
greater than  7-4  litre  (450 in3) would be required.  An engine of this size would
be unacceptable'on  the  grounds of weight and size.  A turbocharged TCCS engine of
5-87 litre capacity was considered to be a more promising approach.

     Exhaust gases  cannot be re-cycled from or to any points between the engine
and turbocharger  without affecting the mass flow and efficiency of the turbocharger,
The gases  must be extracted downstream of the turbine and re-cycled upstream of
the compressor such that the compressor passes a mixture of exhaust gas and air,
whose properties  are not significantly different from those of air alone.  There-
fore, the  standard  procedures for estimating turbocharger engine performance were
applied and the calculated boost density variation throughout the engine speed
range Is shown In Fig.  28.

    'Since a gulp factor of unity occurs at the same engine speed as in the
previous turbocharged In-line 6 TCCS engine, the volumetric efficiency will be
the same.   In  addition, assuming that the ISFC and smoke limited air/fuel ratio
                                                                                31

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are not affected  by  engine  size, and  that  the turbocharger can be linearly scaled
to a  larger engine,  specific  performance will be  Identical with the previous
turbocharged engine  at  Its  optimum  settings.

     One final  problem  remained, that of estimating the performance reduction due
to EGR and combustion retard.   The  only available data published by Texaco concerns
rear wheel torque at one  engine speed.  For a naturally aspirated sub-compact car,
rear wheel torque was reduced  by 31%  as the engine was de-tuned from maximum
economy to 0.4  g/mlle NO  .   In a similar exercise, a turbocharged L141  engine in a
jeep suffered a 29%  loss  In torque.   In the light of this information,  it was
assumed that the  turbocharged  engine  would experience a 31% torque loss over the
complete speed  range, due to  EGR and  retard.  Engine swept volume was increased by
k]% over the primary target engine, to compensate for this torque loss, resulting
in an engine size of 5.8? litre (358  In3).

     A further  requirement  for this engine is that it should be capable of
following the CVS-CH driving  cycle  in the  test car with the EGR operating.
Calculations showed  that  for  typical  vehicle gearing, the car required  36-4 kW
(49 bhp) at 22.S  rev/s  (1350  rev/mln) to meet the maximum acceleration  rate of
the CVS trace  (at the 193 second point), within the specified tolerance.  The
predicted engine  met this requirement, Fig. 29.   It Is clear that road  performance
at full throttle, when  the  EGR Is modulated to zero rate, will be more  than
adequate.

     Two catalysts fitted In  series are recommended to control the HC and CO
emissions.  High  rates  of EGR  will  be required probably ri the region of 25% over
much of the engine load/speed  range,  reducing to about 11% EGR during the maximum
acceleration conditions met during  the CVS-CH test.  EGR will be modulated to
zero rate at ful1 load.

     The high rates  of  EGR  will  increase the engine HC emissions but this increase
will be offset  by the higher  exhaust  gas temperatures to give extra manifold
oxidation plus  Improved catalyst efficiency.  It  is possible that the higher exhaust
gas temperatures  could  make a  thermal reactor a feasible solution together with a
single catalyst.   However,  the lower  cost of having two common exhaust  system com-
ponents, i.e. two catalysts,  has been preferred.

     Catalyst efficiency  and  Its durability factor should be satisfactory for
25,000 mile periods  with  a  reasonable safety margin.

     The NO  emission control  by EGR  to achieve 0.40 g/mile Is the most critical
aspect since the  flame  formed  NO   Is  not significantly reduced by EGR (Ref. Gl
Blumberg).  There is therefore a certain minimum NO  mass emission which increases
with engine capacity, and also the  mass flow of air through the engine.  This
point Is particularly critical for  unthrottled engines.

Design Notes

     Fig. 30 shows the  Installation drawing which is similar, apart from increases
In size and the addition  of the turbocharger, to  that of the naturally aspirated
V-8 TCCS engine.

     The five cylinder  head stud pattern was adopted as for the latter V-8, which
when combined with the  proposed inlet ports gave cylinder centres at 1.2 x cylinder
bore.
 32

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Manifold Arrangement

     Cross flow porting  was  arranged  as  for  the previous V-8 TCCS configuration
with  inboard  inlet manifolds and outboard exhaust manifolds.  The best solution
for turbocharg ing was  thought to be with a single turbocharger mounted at the rear
of the engine banks with the compressor  outlet discharging directly  into the
centrally placed plenum  chamber.  Several other arrangements  involving both single
and dual turbochargers were  considered,  but  all had disadvantages.

Combustion System and  Breathing Considerations

     Most of  the non-dlmenslonal valve and camshaft dimensions were  retained  from
the previous  engines,  but  the piston  cup diameter was  reduced to 50% of the bore.
This  was considered to be  justifiable because of the slightly larger bore size of
this  engine.   It was found that the previously proposed Ricardo helical port  for
the TCCS engine then gave  a  higher swirl level than that which was strictly
necessary.  However, average diesel helical  ports would not give sufficient swirl
performance.  Using rig  swirl measurements from each of these port types, a
hypothetical  port was  derived with a  performance mid-way between these types.  This
port  not only met the  swirl  requirements;  but also allowed some  latitude for
shorter stroke engines,  which improved the volumetric  efficiency.  The important
engine breathing parameters  were:-

              Valve lift/Inner seat  diameter           28%

              Inner seat  diameter/cylinder  bore        38.5%

              Inlet valve opening period               232°

              Average co-efficient of flow  for         _
              hypothetical  port (Texaco definition)

              Average non-dimensional rig  swirl        n
              (Texaco definition)

              Swirl at  end  of induction               3-2  x engine  speed

              Swirl at  TDC                             8.0  x engine  speed

              Unity gulp  factor                       5000  rev/min

Fuel  Injector and Control  System

     As for previous V-8 TCCS engine  configuration

Auxiliary Drives

     Follow those proposed for previous  V-8  TCCS  engine.
                                                                                33

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                       ENGINE CONFIGURATIONS WITHIN CATEGORY  3
     The MAN-FM combustion system was chosen for application  to  the configuration
study in view of  Its economy potential combined with low exhaust emissions.   Even
so, this system has not yet been developed for automotive applications.

     One engine build, a V-8, 5.05 L, has been schemed  to meet the primary
emission target but no engines were schemed for the secondary emission  target.
To achieve the secondary emission target EGR would be necessary and insufficient
published data was available to establish the effectiveness of applying EGR,  or
the penalties Involved.

Category 3

V-8. Natural ly Aspirated - MAN-FM Engine - Primary Emission Target
 Bore

 Stroke

 Bore/Stroke Ratio

 Di splacement

 Compression Ratio

 Power

 BMEP

 Max.  BMEP

 Max.  Torque

 Torque  Back-up

 Power/Unit  Displacement

 Max.  Piston Speed

 Max.  Cylinder  Pressure

 Con-rod

 Distance  between  centres,  L

 Ratio of  L  to  crank  throw  (r),    r

Cylinder  bore  spacing

Package

Engine length

       height

       width
                                     93 mm

                                     93 mm

                                     1.0

                                     5.05  L

                                     15:1

                                     96 kW
                                          at 66.7  rev/s
                                     5.7 bar

                                     7. A bar
                                          at 33  rev/s
                                     298 Mm
                                     19.0 kW/L

                                     12.1* m/s

                                     70 bar
                      3.66 in

                      3.66 in
                      309 in3
                      128 bhp
                             at  *tOOO rev/min
                      82.5 Ibf/in

                      107 Ibf/in2
                             at  1980 rev/min
                      219 Ibf.ft
                            bhp/in3
                      2M»0  ft/mi n

                      1015  Ibf/in2
156 mm               6.1

3.36

     1.2  x  cylinder  bore
                                                               in
                                        mm

                                        mm

                                        iron
                     29.3  in

                     25.3  in

                     25.2  In

-------
       box  volume                    0.307 m               10.8 ft

       weight                         300 kg                660  !b

Predicted CVS-CH  Results

Fuel  Economy                          19.0 miles/U.S.  gallon

Fuel  Consumption                      12.3 L/100 km

HC }                                 0.8/0.3 g/mile
   ) Baseline/Controlled
CO }                                 8.0/0.8 g/mile

NO   Controlled                       1.0 g/mile
  J\

Estimated Noise                       72 dBA

Predicted Performance,  Economy, Emissions and Noise

     The engine swept  volume was calculated to be 5.05L (309 in )  to achieve the
target performance.  Performance predictions were based on extrapolation of the
MAN published  data on  FM engines operating on gasoline.

     Insufficient data  was available to indicate the smoke limited performance
throughout  the engine  speed range and the full throttle air/fuel ratio was
therefore  limited to 18.7 throughout the speed range; this corresponds to Bosch
No. 1 to No.  1.5. The  published values of  indicated specific fuel consumption,
based on the  results from several FM engines, were therefore adjusted to give the
indicated specific air  consumption when smoke limited.

     The prediction  of  volumetric efficiency was not possible from published FM
data and had  to be made by extrapolation of Ricardo  'in house1  information on
the performance of high swirl  inlet ports in  larger  bore  (truck size) engines.
Imep was calculated  from the indicated specific air  consumption and volumetric
efficiency,  then  brake  performance was obtained by taking  the friction levels shown
in Fig. 3.10  into account.

     The estimated performance curve for this engine is shown  in Fig. 31.  Analysis
of typical  FM  test bed  bsfc curves indicates  that the estimated fuel consumption
of the test  vehicle  should be excellent during the CVS-CH  emission test cycle.  The
moderate CR  of 15 also  contributes to good economy.

     A single  oxidising catalyst must be fitted underneath the  vehicle floor and
as close to  the engine  as possible.  Low thermal inertia exhaust manifolds are
also recommended. Catalyst durability should not be problematic for a period of
25,000 miles  since the  uncontrolled engine emissions of HC will be comparatively
low at about  0.8  g/mile.  Furthermore there should not be  a durability problem  in
holding the  NO emission to within the primary emission target  since no EGR  is
necessary.

Design Notes  (Figs.  32. 33. 3*0

    •The choice of a bore/stroke ratio of 1 was made in the interests of com-
pactness since this  was the highest bore/stroke ratio recommended by MAN.
Furthermore,  from the  design point of view  it gave a compromise between noise,


                                                                                 35

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 breathing and engine height.

      The  major dimensions, design and  rigidity of the crankcase and crankshaft
 lie between conventional  gasoline and diesel engine practice since the maximum
 cylinder pressures are higher than for  gasoline engines but not quite at diesel
 engine levels.  Cylinder  centres resulted at 1.2 x cylinder bore.

      An overhead camshaft arrangement was considered to offer considerable
 advantages over a pushrod design in terms of cylinder head simplicity and
 available space within the head for locating the high swirl inlet port required
 for this combustion system.  The resulting complexity of the front end timing
 and auxiliary equipment drives, together with the engine length penalties incurred,
 were however considered unsuitable features for passenger car application.  A
 single camshaft and pushrod design was  therefore adopted.

 Cylinder Head and Manifold Arrangement

      This was Cross-flow porting with an  inboard inlet manifold and employing
 high swirl type inlet ports.   A four cylinder head stud pattern was considered
 to give the best head layout.

      Fuel injectors are placed on the inboard side together with pushrods and
 inlet ports.  Spark plugs and exhaust ports are placed on the outboard side.
 The spark plugs are retained by the use of screwed sleeves and the injectors
 via clamps.

 Combustion System and Breathing Considerations

      The combustion chamber bowl is located within the piston crown and is
 offset from the bore centre by A.5 mm (equivalent to O.O'fSS x cylinder bore).
 The relative positions of the injector  and spark plug are essentially to MAN
 requirements on opposite  sides of the piston bowl, see Fig. 33.  Conventional
 ignition equipment and long electrode spark plugs are used.

      The  inlet valve inner seat diameter  is 38.5 mm, about k\ .W, of the bore,
 which gives a mean Inlet  gas velocity of about 12 m/s (236 ft/sec) at the rated
 speed.

 Fuel Injector and Control System

      The fuel Injector is a single hole type which is similar to that fitted
 to direct injection diesel engines.  It has a single offset spray directed at
 the adjacent wall of the  piston cavity. Ricardo have Installed the nozzle into
 an Injector body of 17 mm diameter as in some recent diesel engine design practice.
 at
  A gear driven rotary Injection
the front.
                                     pump is  positioned between the engine banks
Auxi1iary Drives

      The camshaft,  fuel  injection pump and  hydraulic pump are driven by an
internal  gear system.   Gear drives give good  reliability and accuracy of timing
over  long periods with low noise.  The distributor  is skew-gear driven off the
camshaft  and  Is  mounted  in the vee at the  rear of the engine.

     Twin V-belt drives  are used for the alternator and water pump and a single
36

-------
V-belt for the air conditioning unit.  A conventional  skew  ijear  Jrive  is  useJ toi
the oiI  pump.
                                                                                  37

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                        ENGINE CONFIGURATIONS WITHIN CATEGORY 4

       The VW combustion  system was  chosen for application to the configuration study
  since, at  the  time  of writing,  it  was  the only one which had been tested in multi-
  cylinder form  and for which performance results were available.   More recently the
  Porsche system has  been tested  in  multi-cylinder form, however performance data is
  still not  sufficient  to warrant  a  configuration study.

       The same  engine  V-8 configuration of 3,671 was schemed to achieve both the
  primary and secondary emission targets.  Low NO  emissions were  achieved from the
  secondary  engine  by applyIng^EGR.

  Category 4

  (1)  V-JL  Naturally Aspirated -  VW Engine - Primary Emission  Target
 Bore

 Stroke

 Bore/Stroke Ratio

 Displacement

 Compression Ratio

 Power

 BMEP

 Max. BMEP

 Max. Torque

 Torque Back-up

 Power/Unit Displacement

 Max. Piston Speed

 Max.  Cylinder  Pressure

 Con-rod

 Distance  between  centres,  L
                                L.
 Ratio of  L  to  crank  throw  (r),  'r

 Cylinder  bore  spacing

Package

Engine length

       height
                                       86 mm

                                       79 mm

                                       1.1

                                       3.67 L

                                       8.5:1

                                       96.5 kW
                                              at  75  rev/s
                                       7.1  bar

                                       7.8  bar

                                       228  Nm

                                       9.8*

                                       26.3 kW/L

                                       11.8 m/s

                                       58.6 bar
at 66 rev/s
               3.39 in

               3.11 in
               224 in3
129 bhp
       at 4500 rev/min
103 lbf/in2

113 lbf/in2
       at 3960 rev/mln
168 Ibf.ft
               0.576  bhp/in3

               2330 ft/min

               850 lbf/in2
                                       148.8 mm              5.7 in

                                       3-67

                                             1.17 x cylinder bore
                                      763 mm

                                      610 mm

                                      610 mm
              30.05 In

              24.0 in

              24.0 in
38

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       box volume                    0.28A m                10.0  ft

       weight                         250  kg                 550  Ib

Predicted  CVS-CH Results

Fuel  Economy                         16.5 miles/U.S.  gallon

Fuel  Consumption                     H».2 L/100  km

HC )                                  1.8/0.23 g/mile
   )  Baseline/Controlled
CO )                                  8.0/0.8  g/mile

NO   Controlled                      1.0  g/mile
  f\

Estimated  Noise                      73 dBA

Predicted  Performance,  Economy, Emissions and Noise

     The engine swept volume necessary to achieve the target vehicle performance
was calculated to be 3-67L (22*4 In3).  Performance prediction for  the configurated
engine was made by extrapolation of the published data from the k  cylinder VW
stratified charge engine.

     The method adopted for the extrapolation of data from the original  VW engine,
was first  to determine the gulp factor and  volumetric efficiency.   Then  the
friction losses (assumed to be equivalent to a standard gasoline engine) were
added to the published bmep in order to obtain the imep.  Finally, the ratio of
imep divided by volumetric efficiency was plotted against engine speed.

     The proposed bore/stroke ratio of 1.1  is lower than the original VW engine
which has  a bore/stroke ratio of 1.2**, therefore the proposed engine bmep could
not be the same as for the original VW engine.   In this case Ricardo assumed that
the variation  of the ratio imep/volumetric  efficiency was the same for both engines
throughout the speed range.  The proposed engine  imep was then calculated, having
first predicted the volumetric efficiency by the gulp factor procedure.   Brake
performance was finally obtained by subtracting  the standard gasoline engine
friction losses.  In order to arrive at the correct engine capacity and  performance,
a step by  step procedure had to be adopted, making, as the first step an
approximation  of the capacity, then reiterating  the calculation until the target
horse-power was achieved.

     The estimated performance curve of this engine is shown in Fig. 35.   It can be
seen that  peak torque Is developed at a high engine speed, however  in practice this
is not significant since the torque curve Is virtually flat between kO  rev/s and
67 rev/s.

     To control the engine HC and CO emissions,   a  large oxidising catalyst is
recommended, so that a durability of at least 25,000 miles can be achieved.  Low
thermal inertia exhaust manifolds are also recommended, leading to  the catalyst
underneath the vehicle floor.

     The engine emissions  of NO  will be within  the primary target without EGR.
No special durability problems of NO  control are envisaged.
                                                                                39

-------
 Design Notes (Figs. 36. 37. 38)
                            •*
      The choice of a bore/stroke ratio of  1.!  instead of the standard VW bore/stroke
 ratio of 1.2*1 was made because the smaller bore should give better combustion
 (lower emissions) and adequate breathing without  increasing engine height sig-
 nificantly.   Furthermore engine noise will  be  lower.  A C.R. of 8.5:1 was used,
 common to VW.

      The engine lower end follows conventional gasoline engine practice as does the
 cylinder bore spacing at 1.17 x cylinder bore which was controlled by the casting
 core thickness of the water jacket between bores.

 Cylinder Head and Manifold Arrangement

      The inboard inlet manifold and outboard exhaust manifold give cross-flow
 porting with a single throttle as for all  previous V-8 configurations.  To give
 satisfactory spark plug and fuel  injector  accessibility, the pre-chamber had to be
 positioned on the outboard side and not Inboard where otherwise it would be
 preferred.  The ports pre-chamber and pushrods could not all be accommodated on
 one side.  The fuel lines and spark plug wires are therefore unavoidably long and
 also the fuel Injectors determine the engine width, Fig. 38.  The exhaust ports
 were unswept In order to reduce pre-heat to the fuel Injectors, see Fig. 37-

      A four cylinder head stud pattern and  conventional rocker gear have been used.
 The cylinder head has been designed to employ the minimum number of machining
 operations commensurate with  the complexity of the VW system.

 Combustion System and Breathing Considerations

      The combustion system is based on the VW system with a pre-chamber volume of
 about 20£ of the total clearance volume.   The throat area was calculated from the
 relationship (see Part 2 of Report).

                   vol. pre-chamber  _ (1 -  F) =  7  cm
                     area throat       (CR)Y~I

                   where F =vol. pre-chamber
                            clearance volume

      The transverse plane on  the cylinder  bore centre runs through the centre of the
 pre-chamber  and its throat.   Fig.  37 shows  the combustion chamber, spark plug and
 Injector layout and relative  positions which are Identical to the VW system.  The
 pre-chamber  injector and spark plug are arranged in sequence in the flow direction
 so  that  the  spark plug receives a  pre-prepared mixture.

      In  order not to overcool  the  combustion faces of the pre-chamber (critical for
 HC  emissions),  a controlled amount of air  cooling by means of fins has been used in
 preference  to water cooling.

     The  inlet  valve inner  seat diameter is 3^.1 mm or 39.6% of the bore.  This
gives a mean  inlet  gas velocity at maximum speed (7^.5 rev/s) of 76 m/s.

Fuel  Injector and  Control  System

     A fully  mechanical  Injection  pump supplies the fuelling necessary to both the
pre-chamber and  inlet  port  Injectors.  A camshaft operates the injection plungers

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and is gear driven  from the camshaft.   The Injection pump is kisod  on  t ho sy.trm
by Schafer  fitted  to the VW pre-chamber engine.   It contains 12 c\ims operaiiiui  Ib
injector plungers and uses  components  from standard fuel  injection  equipment.   The
pump shown  Is  basically an  In-line pump but with offset injection lines to give
short length.   A 90° VI2 pump layout for even shorter length was investigated  but
could not be Installed because of interference with the front of the  inlet
manifolds.

     Injectors for  the pre-chamber are controlled separately, one per  cam (8 cams
in total),  whereas  those for the Intake port are supplied In pairs  from a single
cam (k cams In total).

     Pre-chamber  Injection  quantities  are fixed at 2 mm /stroke with  an optimum end
of injection stroke of 70 deg crank angle b.t.d.c.  The fuel delivery  into the
intake port Is varied by a  spatial cam having a pre-determined contour with the
parameters  speed and load.   A control  box containing the spatial cam is fitted
adjacent to the front four  intake port injection lines on the  injection pump and the
fuelling delivery  Is varied by means of the conventional  helix  'cut off/rack
method.  The spatial cam is positioned by engine speed and  intake manifold
depression.

     The nozzle Is  a single hole type  with an opening pressure of 25 bar, and
injects a spray with about  20° offset.  Port injectors have the same opening
pressure and spray  a cone envelope of fuel directly onto the back of the  Inlet
valve.  A secondary Injector is included In the intake manifold for cold  starts.

Auxiliary Drives  (Fig. 36)

     Camshaft, fuel injection pump and hydraulic pump are gear  driven from the
front of the crankshaft. Twin V-belt  drives are used for the  alternator  and water
pump and a  single  V-belt for the air-conditioning unit.  A  conventional skew gear
drive Is used  for  the oil pump and the distributor  is skew  gear driven from a
gear on the camshaft nose.

Category *t

(2)  V-8, Naturally Aspirated - VW Engine - Secondary Emission  Target

     Engine Specification  Identical To Previous VW  Engine

Predicted CVS-CH Results

Fuel Economy                          15-5 miles/U.S. gallon

Fuel Consumption                      15-13 L/100 km

HC )                                   2.5/0.28 g/mile
   )  Baseline/Controlled
CO )                                   12.0/1.0 g/mile

NO   Controlled                       0.35 g/mile
  /\

Estimated Noise                       73 dBA

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predicted Performance, Economy, Emissions and Noise

     The performance prediction was identical to that used for the previous VW
engine and the same engine build is proposed.  Because this stratified charge
engine inherently gives low NO  emissions, it is unnecessary to penalise the
engine performance by the addition of EGR at the maximum loads of the CVS test.
The EGR is only used at part load conditions.  The estimated performance curve is
shown in Fig. 35 as all the performance specifications are identical to the previous
configuration.

     Two oxidising catalysts fitted in series will be necessary to control the HC
and CO emissions and EGR to control the NO  emissions.  Emission control durability
                                          x
should be satisfactory for intervals of at least 25,000 miles.  The addition of
EGR causes a small penalty in Fuel  consumption.

     Since VW have not attempted to meet the secondary target with this combustion
system,  the proposition that performance will not deteriorate is speculative.

Design Notes

     Identical to previous VW V-8 configuration shown in Figs. 36, 37 and 38.

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                      ENGINE CONFIGURATIONS WITHIN CATEGORY 5
     The most developed variant of the 3~valve stratified charge engine is the
Honda CVCC.  It is the only system in volume production for automotive applications
and was therefore the obvious choice for the configuration study.  One engine build
has been schemed to meet the primary emission target:-
(1)  V-8, ^.28L, CVCC engine

Also, one engine build has been schemed to meet the secondary emission target:-

(2)  V-8, 5.58L, CVCC engine

Category 5

(1)  V-8, Naturally Aspirated - CVCC Engine - Primary Emission Target
Bore                                 88 mm

Stroke                               88 mm

Bore/Stroke Ratio                    1.0

Displacement                         k.2& L

Compression Ratio                    7.9:1

Power

BMEP

Max. BMEP                            7-9 bar

Max. Torque                          268 Nm

Torque Back-up                       26.k%

Power/Unit Displacement              22.8 kW/L

Max. Piston Speed                    12.9 m/s

Max. Cylinder Pressure               58.6 bar

Con-rod

Distance between centres, L

Ratio of L to crank throw (r),   r

Cylinder bore spacing

Package

Engine length                        761 mm

       height                        660 mm

       width                         6k2 mm
                                V
                                                           3.»  in

                                                           3.*»6 in
                                                           260 in3
                                     97.5 kW               130.5 bhp
                                            at 73.5 rev/s           at MOO rev/mi n
                                     6.25 bar              90.5 lbf/in2

                                                           115 lbf/in2
                                            at 35 rev/s             at 2100 rev/min
                                                           197 Ibf.ft
                                                           0.502 bhp/in-

                                                           25^*0 ft/min

                                                           850 lbf/in2
H»8.6 mm              5.85 in

3.38

       1.22 x cylinder bore
                                                           29.96  in

                                                           25.99  in

                                                           25.28  in

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        box volume                     0.322 m                11.4 ft

        weight                         250  kg                 550 1b

 Predicted  CVS-CH Results

 Fuel  Economy                         16.8 miles/U.S. gallon

 Fuel  Consumption                      13-95 L/100 km

 HC    Controlled                       0.2  g/mile

 CO    Controlled                       2.7g/mile

 NO    Controlled                       1.3  g/mile
  /\

 Estimated  Noise                       73 dBA

 Predicted  Performance,  Economy,  Emj^sjons^ and Noise

      The starting  point for  performance calculation was to  calculate the ratio of
 Imep  to volumetric efficiency  for  the Honda,  1.5L CVCC engine, and a 5-73L CVCC
 engine.   Imep was  calculated from  the published bmep and an estimated fmep was
 added.   The friction  losses  of a standard gasoline engine were assumed, with a
 small addition  (.035  bar)  for  the extra valve gear.

      A  proposed V-8 engine of 4.26L and bore/stroke ratio of 1 will achieve the
 target  brake performance.   In the calculation, the ratio of imep to volumetric
 efficiency is kept  equal  to  that of the Honda engine at the same piston speeds.
 Volumetric efficiency of  the proposed engine was predicted by the same method
 as  for  the Honda engine and  thus the  imep was estimated.  Brake performance was
 therefore  obtained  using  the same friction losses as above and Fig. 39 shows the
 resulting  power and torque curves.

     A  thermal reactor  has been  fitted in between the engine banks to give a
 compact  system which  is Ideal for exhaust treatment.  The lowest exhaust
 emissions  from a V-8 3  valve engine have  been obtained with this configuration
 (see  literature survey).  Carburettor pre-heating, an inherent requisite of the
 CVCC engine, is obtained by arrangement of the carburettor to sit on top of the
 thermal-reactor, see Fig. 42.  No catalyst or EGRwill  be necessary for the
 primary emission target.

     Emissions durability of this vehicle should be acceptable for 50,000 miles
 although It  Is dependent on the physical  integrity of the thermal reactor.  Since
 there is no  catalyst, the engine fuel can be either leaded or a leaded gasoline.

 Design Notes (Figs. 40. 41, 42)

     A bore/stroke  ratio of  1 was chosen  for the purpose of obtaining adequate
 breathing without compromising engine height.  The Honda CVCC engines use bore/
 stroke ratio ranging from 0.85 to 1.15.   A compression ratio of 7-9:1 is used,
 common to  the Honda engine.

     The engine Installation drawing, Fig. 40, shows the engine package.  Cylinder
centres at  1.22 x cylinder bore were controlled by the cylinder head layout to
accommodate  the extra valve and Its rocker gear.   An overhead camshaft was also

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 found to be necessary.

      Combustion chamber  geometry was  based on the Honda conversions of their 1.5L
 engine and one American  V-8 engine, the  Impala.

 Cylinder Head  Layout

      A thermal reactor between  the engine banks was chosen as the optimum position
 for the V-8 configuration.   This determined  that the cylinder head porting should
 be uni-sided with  Inboard inlet and exhaust  ports and also that the auxiliary
 valve assembly/pre-chamber  should be  in  the  remaining space on the outboard side.
 A cross drilling Is  used to supply the mixture charge to  the auxiliary chamber, as
 Indicated in Fig.  1*1.

      An overhead camshaft was  found to be the best solution to operate the required
 valve gear of  the  CVCC system.   Insufficient space was available for  the con-
 ventional  inboard  push rod  arrangement due to the space occupied by having inboard
 inlet and exhaust  ports. Two  outboard camshafts with outboard push rods was one
 alternative but the  overhead camshaft was chosen for greater cylinder head
 simplicity, reduced  cylinder head width  and  with only a marginal sacrifice in
 engine height.

      The camshaft  has  three cam lobes per cylinder with rocker followers to each
 of the three valves. The rockers operate on the valves via rollers which give low
 side  thrust, low wear and also  lower  engine  height compared to the standard screw
 type  adjusters.  Tappet  clearances are adjusted by means  of an eccentric adjustment
 on the bearings of the rollers  which  can be  locked in position.

      Exhaust port  liners have  been fitted  into the cylinder head for  insulation  in
 the Interests  of maintaining high exhaust gas temperatures.

 Manifold Layout

      The exhaust manifold assembly, designed as a thermal  reactor, has a cast iron
 outer shell  with a stainless steel fabricated  inner construction, as  shown  in Fig.
 1»2.

      There Is  a split  line  (now shown)  in  the cast iron shell to allow for
 installation of the  internal components.   Exhaust gas from the engine is diverted
•into  the Inner concentric tube, the gases  then flow towards the front of the engine,
 out through an open  end  and finally are  channelled to the rear exit through the
 circular gap between the inner  and outer steel shells.

      The volume of the total thermal  reactor is greater than the engine displacement
 and this should result in satisfactory exhaust gas residence time for HC and CO
 oxidation  when combined  with the high gas  temperatures.

      The exhaust gas exit from  the rear  end  of the reactor is angled  to direct the
 exhaust pipe for its passage between  the rear of the  left hand bank and the vehicle
 bulkhead.   Consideration of space and suitable insulation because of  the close
 proximity  to the bulkhead will  have to be made to accommodate this proposed position
 of the exhaust pipe  to sweep over .the top of the left hand bank rocker cover.
 Neither of these exhaust pipe arrangements have been  indicated in the installation
 package size.

      The carburettor supplies  two different mixture charges, one a rich charge to

-------
 the pre-chamber and the other  a  weak  charge  to  the cylinder.  A hot spot from the
 Inner concentric shell  of the  thermal  reactor ensures  that both charges are
 vaporised before dividing between  the runners.  Exhaust gas heats the und rside
 of the manifold evaporative floor.

 Combustion System and Breathing  Considerations

      The combustion system Is  based on  the Honda CVCC  engine.  Pre-chamber volume
 was arranged  to be about 3% of the total clearance volume and the ratio of throat
 area divided  by pre-chamber volume was  0.1 cnr1. A thimble type of auxiliary chamber
 unit Is used,  the outlet orifice of the thimble being  the throat.  The spark plug
 is in a position to avoid direct fuel or charge Impingement.

      Inlet ports are designed  for high  volumetric efficiency, there being no
 necessity for  organised swirl.   The inlet valve inner  seat diameter is 36.1 mm,
 about b]% of  the bore,  which gives a  mean inlet gas speed of 76.8 m/s at 73-5 rev/s.

 Auxiliary Drives (Fig.  AO)

      Both overhead camshafts are driven by a single toothed belt, the back of which
 is poly-V form and Is used  to  drive the water pump.  The water pump is mounted on
 adjustable feet to the  engine  and  Is  used as the tensioner.

      A single  V-belt drives the  air conditioning unit  and a twin V-belt drives the
 alternator and hydraulic pump.   A chain from the crankshaft drives an intermediate
 gear from which a  skew  driven  shaft drives both the distributor and oil pump.

      The  complexity  of  the  front end  drive systems on  this overhead camshaft engine
 is apparent.   The  proposed  arrangement  is not definitive since there are several
 feasible  methods.  Toothed  belts for  the camshafts are, however, considered the best
 solution  In comparison  to chain  or gear driven camshafts.

 Category  5

 (2)  V-8,  Naturally  Aspirated  -  CVCC  Engine - Secondary Emission Target
Bore
Stroke
Bore/Stroke Ratio
Displacement
96 mm
96 mm
1.0
5.56 L
3.78
3.78

3*0 i
in
In

in3
Compression Ratio                    7.9:1

Power                                121 kW                162 bhp
                                           at 66.7 rev/s          at 4000 rev/min
BMEP                                 6.5 bar               94.5 lbf/ln2

Max. BMEP                            7.9 bar               115 lbf/ln2
                                           at 33-5 rev/s          at 2000 rev/min
Max. Torque                          350 Nm                258 Ibf.ft

Torque Back-up                       21.5%


46

-------
795 mm
675 mm
67^ mm
0.362 m3
273 kg 1
31.3 in
26.58 in
26.5 in
12.8 ft3
600 Ib
Power/Unit Displacement              21.8 kW/L             0.^76  bhp/in3

Max. Piston Speed                    12.8 m/s              2520  ft/min

Max. Cylinder Pressure               58.6 bar              850  lbf/in2

Con-rod

Distance between centres, L          162.2 mm              6.39  in
                               L/
Ratio of L to crank throw (r),   r   3.38

Cylinder bore spacing                       1.22 x cylinder bore

Package

Engine length

       height

       width

       box volume

       weight

Predicted CVS-CH Results

Fuel Economy                         15 miles/U.S. gallon

Fuel Consumption                     15.63 L/100 km

HC   Control led                      0.37 g/mlle

CO   Controlled                      3.0g/mile

NO   Controlled                      0.37 g/mile
  X

Estimated Noise                      73 dBA

Predicted Performance. Economy. Emissions and Noise

     Published data indicate that the amount of EGR necessary to achieve the
secondary NO  target will produce an imep loss of about 15%.  In order to offset
this torque Toss and so maintain the prescribed performance levels, means that the
engine capacity must be increased from that used for the primary target to 5.56L
(3*»0 In3), i.e. a capacity increase of about 30%.

     Performance predictions were made, assuming the addition of 111 proportional
EGR over the engine spectrum and at maximum load of the CVS-CH test, using the
same method as described for the primary target CVCC engine.  The imep of the Honda
engine was first reduced by 15% in order to obtain the new ratio of imep to
volumetric efficiency with the addition of EGR.  The target power output of 96 kW
(128 bhp) was met, with EGR, at 66.7 rev/s.

     In practice, EGR will  be reduced to zero rate at full throttle and therefore

-------
 the true power output will be that calculated without EGR.  Performance curves
 presented  in Fig. 43 show both conditions.  Obviously the vehicle performance will
 be more than adequate since the maximum power is 121 kW (162 bhp) at 66.7 rev/s.

     Emission control Is achieved with an inboard thermal  reactor as for the
 previous CVCC engine.  EGR Is recycled into the inlet system through a single pipe
 downstream of the carburettor.  The quantity of EGR necessary to achieve 0..41 g/mlle
 of NO  is estimated to be 11% over the load range up to and including the maximum
 load condition of the CVS-CH test.  EGR can be modulated to zero rate for all load
 conditions In excess of the latter.

     It should be noted that because the HC and CO emissions are only marginally
 within the secondary target due to the effects of EGR, it  may prove necessary,
 dependent on vehicle tests, for an oxidising catalyst to be fitted.  However, no
 cost allowance has been Included in this study to allow for this.

     Emission durability of the HC and CO emissions will be difficult for periods
 in excess of 25,000 miles.  Again, like the previous engine, the physical integrity
 of the thermal  reactor Is critical.

 Design Notes

     The design Is Identical but Increased in size to the  CVCC engine schemed to
meet the primary emission target.  Only an Installation drawing, Fig. 44, is
 therefore presented to allow an assessment.

-------
                                                                                                          I I E

i»v...«; a
c*v-. IM :j,
'RX: /»
'•'X'. :.4
»«oca /«
ICC5 VI
TICS :i6
cv KOTART
ices vt
KM FM vt
vw vt
vw vt
cvcc vt
cvcc vt
OICStL VI

'.ATISOK
iASOUK
iAlOlIN
I
•'
I
II
:i
• i
ii
in
i»
rv
¥
V

EMISSION
TARGET
PRIMARY
PRIMARY
PRIMARY
PRIMARY
SECONDARY
RIMARY
•IMAHY
P*INA*Y
ECOKOARY
RIMAAY
raiwuiv
ECONOARY
RIMARY
ECONOMY
PRIMARY
ENCINE SPECIFICATION
IORE ISTROKE 'CONFIC-JOISPLACE-
•M ! wn URATION MENT L
97
18
87
96
»»
95
9*

101
93
74 "*
" ] V8
12
17
M
»*
S5
»*

»J
13
NA
1L6
NA
V8
C.«.
*-5
2. 59
I..15

11.0
R6 »-'5 !"•«
V8
NA
V8
TC
IL6
2 SANK
ROTAAr
TC
V8
NA
V8
5.25
5.".
I..K,
5.5
5.87
5.05
n.o
10.0
9.0
8.5
9.0
15.0
•6 75 j JJ 3.67 8.5
86
7> " : 3.67 8.5
M ; " i vt *•'«
H ;
M :
** V8
»« 1 vt
7.5
5.56 7.S
*.78
20
PACKAiE
LENGTH
mm
HEIGHl
nm
WIDTH
ntn
sox
VOUHE m3
NOT CONFIGURED
NOT CONFIGURED
770
995
800
823
981
523
8*5
7kS
763
763
761
7S5
758
597
600
6}8 1 528
60S
oS8
610
660
M5
613
610
610
660
675
60k
622
622
578
W-.
6JO
6*0
610
610
6*2
67»
692
.275
WE 1 GMT
kg
2*5
20*
250
.335 ; 263
.303
.337
-3*6
.2k
.3»3
.307
.2823
41
298
33
228
66
228
66
268
35
350
35.5
!86
33.*
TOHQUE
SACIQJP t
J5
20
19
26
1]
23
15. »
17. »
19.0
2*. 6
9.8
9.8
26.*
21.5
2*.0
VEHICLE PERFOSHANCE
ECONOMY
n/USg*l
16
17.*
18.7
18.*
16.5
17.0
17.0
t*.o
U.O
19.0
16.5
15.5
16.8
15.0
21.0
CONSUMPTION
I/ 100 kin
Ik. 6
13.5
12.5
12.75
Ik. 2
13.B
13.8
16.7*
16.7*
U.3
i*.2
15.13
13.95
15.6
11.0
HC CHNTKOL
HC BASE
0.2
1.8
0.2
1.8
0.15
1.0
0.15
1.0
0.25
2.5
0.3
2.5
0.22
2.0
0.3
3.0
0.25
*.5
0.3
0.8
0.23
1.8
0.28
2.5
0.2
0.37
O.kt
CO CONTROL
CO BASE
1.0
30.0
1.0
30.0
1.0
8.0
0.8
8.0
0.8
12
1.5
10
1.5
10
0.8
15
1.0
12.0
0.8
8.0
0.8
8.0
N0«
1.3
NOISE
06A
71
1
1.3 73
l.k i 71
1.3
0.37
0.8
0.8
1.0
0.33
75
72.5
70.5
EXISS ON CONTROL
CATALYST
1 EXH.
AIR INJ.
1 EXH.
AIR INJ.
1
1
2
2
7. : *
71
	
72.5
1.0 72
1.0
73
ii:S °-35! "
2:7 N.3 73
3.0
2.0
0.37 : 73
1.2
7*
2
2
1
THERMAL '
REACTOR . "
; X
I
j X
X
X
1 >
X
; «

«

, j
2

X
X
1
X X
1

10

-------
     Figure  1.   Estimated Performance  Curve  for 0 97 x 76 mm V8 Gasoline Engine
     for Primary Emission Target.
   BARE ENGINE
A.I.T. 20UC
BARO 760 mm Hg
   ENGINE BUILD:  CLOSE TOLERANCE SOPHISTICATED CARBURETTOR, MODULATED EGR,
                  AIR INJECTION OXIDATION CATALYST
    1*0
    30-
              1000
                3000
          rev/min
50

-------
         Figure 2.  Estimated Performance Curve for 0 88 x 82 mm 6 Cylinder
         "European Type" Gasoline Engine for Primary Emission Target.
     BARE ENGINE
                        A.I.T. 20°C
                              BARO 760 mm Hg
     BUILD:   PETROL INJECTION, MODULATED EGR, AIR INJECTION, OXIDATION CATALYST
 130-
 120--90
 110-
 100.
  90-
  80.
Q.

-O
 70.



 60-



 50.



 40'



 30 H
     HOO-
     kyo
-60-
   UJ

   O
   O-
-50
 •30-
      •20
    10
        20
         1000
                     POWER
30
 i
                    2000
                                            ENGINE SP
50
                                             rev/s
                                                ED
60
I
                  3000
               4000
                                              rev/min
                                                                              Nra
                                                                              T
                                                                              Q.


                                                                              .0
                                                                           -- 130
                                                                                   120
                                                                               10.5
                                                                                   100
                                                                                   90
30
90
 I
                     5000
                                                                                   51

-------
   Figure 3.  Estimated Performance Curve for 0 87 x 87 mm V8 Configuration
   Category 1.
   BARE  ENGINE
A.I.T. 20 C
BARO 760 mm Hg
           PRIMARY  EMISSION  TARGET     PROCO COMBUSTION  SYSTEM
                                                                      10.
   130-
   120-
   30
                            2000
              3000
4000
                                    rev/mln
52

-------
                          Figure 4.   E.P.A. Light  Duty Stratified Charge Project.  Task  II  - Configu-
                          ration Study.  Category  I  - V8 Ford  'PROCO1  System, Installation  Drg.,
                          Primary Emission Target.
 HYOWXAJC PUMP
                                                                                                                     415 L.iftk
                                                                                                             BOX VOL   2751^'
                                                                                                             tST N^IGWT  t»O
en
CO

-------
tn
                        Figure  5.   E.P.A. Light Duty Stratified Charge Project.  Task II Configuration.
                        Category  I —  V8  Ford  'PROCO' System, Cylinder Head Layout, Primary Emission
                        Target.
        VIEW  ON CYLINDER   SECTION  A A
         HEADRACE
PLAN  VEW

-------
Figure 6.  E.P.A. Light Duty Stratified Charge Project.  Task II Configuration
Study.  Category I - V8 Ford 'PROCO1 System, Cross Section Arrangement, Pri-
mary Emission Target.
                                                                                    55

-------
          Figure 7.   Estimated Performance Curve  for 0  96 x 96 mm  In-line 6 Con-
          figuration - Category 1.
        BARE ENGINE
A.I.T. 20°C
            BARO 760 mm  Hg
                   PRIMARY EMISSION  TARGET    PROCO COMBUSTION SYSTEM
            r 100
       130
       120.-90
                1000
2000
3000
                                                                               140
                                                                              U130
                                      ENGINE SPEEC

                                       40  rev/s
                                        I
                                         rev/min
56

-------
                        Figure  8.   E.P.A.  Light  Duty  Stratified Charge Project.  Task II Configuration
                        Study.   Category.!  -  In-line  6 Ford 'PROCO1  System, Installation Drg., Primary
                        Emission  Target.
   HYDRAULIC
en

-------
       Figure 9.  E.P.A. Light Duty Stratified Charge Project.  Task II Configuration
       Study.  Category I - In-line 6 Ford 'PROCO1 System, Cross-sectional Arrange-
       ment, Primary Emission Target.
58

-------
Figure 10.  Estimated Performance Curve for 0 94 x 94 mm V8 Configuration
Category 1.

     BARE ENGINE         A.I.T. 20°C          BARO ?60 mm Hg
          SECONDARY EMISSION TARGET  PROCQ COMBUSTION SYSTEM
     	 PERFORMANCE WITH  15*  EGR
                       I          I
          1000
2000
3000
14000
                                   rev/mi n
                                                                                 59

-------
                       Figure 11.   E.P.A Light Duty Stratified  Charge Project.  Task  II  Configuration
                       Study .  Category I - V8 Ford  'PROCO'  System, Installation  Drg.,  Secondary
                       Emission Target..
HYDRAULIC PUMP
                                                                                                            STROKE   »4 «.««
                                                                                                            • HP     *l K.W
                                                                                                            BMtP

-------
Figure 12.  Maximum Power Operating Conditions for L141 TCCS Engines at Two
Smoke Levels.
                           NATURALLY  ASPIRATED
      $    TOYOTA  DATA ON LlM  BOSCH SMOKE NO.  k
      <8    TEXACO   '	NO.  k
      0      "      "    "    "      "     "   NO.  2i-2
60
                                   ENGINE SPEED rev/s
                                                                                 61

-------
        Figure  13.   Indicated Specific Air Consumption for L141 TCCS Engines at Two
        Smoke Levels.
                              NATURALLY  ASPIRATED
         ©  TOYOTA DATA ON L1*»1  BOSCH  SMOKE  NO.  k
         Q
     10
      9 •
      8 -
      7-
     6-
   'a.
   £ 5H
  TEXACO  "

     ii    ii


INDICATED
SPECIFIC AIR
CONSUMPTION
  NO. A

  NO. 2i-2
         •5500
         •5000
         •4500
         -4000
         3000
               cn
     3-
     2-
        -2000
     1 -
        -1000
                        1000
rev/mln

 2000
   i  '
                                                   3000
                  10
—T
 20
—T
 30
                                        40
                     50
60
62
                                      ENGINE SPEED  rev/s

-------
         Figure  14.   Motoring Friction of LI41 TCCS Engines,
  50
   1*0
   30
CL.
LLl
   20
   10
                          ENGINE NO. 1

                          ENGINE NO. 2

                          ENGINE NO. 3
f J.p

•3.0
-2.5

•2.0
(0
-Q
•1.5
^
•1.0
•0.5
10




/
g
<


00 15
i


/
/

c
1 "'\
)
>


00 20(
1

/
/


\/'*
1 I
> \J


rev/m I n
30 25
1
/
/


/X^
'' \
}
\



00 3C
1
/


4
X
)
•\
i



)00 35
i



/
/
S





00 ^0
1

30
ill iii
]0 20 30 **0 50 60
                                ENGINE SPEED - rev/s
                                                                              63

-------
Figure 15.  Estimated Performance Curve for 0 95  x 95  mm Naturally  Aspirated
V8 Configuration - Category 2.
BARE ENGINE
                 A.I.T. 20°C
                         BARO 760 mm Hg
         PRIMARY EMISSION TARGET    TCCS COMBUSTION SYSTEM
   130-
   120-
   110-J
   100-
    90-
    80'
    70-
    60-
    50-
    30-
        100
"90
       -80
                                                                      10-1
 20      20
30
*»0rev/s  50
            1000
                    2000
                                    rey/mln-
                  3000
                                                            4000

-------
                            Figure 16.   E.P.A.  Light Duty Stratified Charge Project.   Task II Configuration
                            Study.  Category  J.-.-V8 Naturally  Aspirated TCCS System,  Installation  Drg.,
                            Primary Emission  Target.
   WORAUIIC PUMP
      ALTERNATOR
CTl
tn
                                                                                                                •HP    «fc kV
                                                                                                                •MCP    9 ft hw
                                                                                                                CAWsClTY  1-4
                                                                                                                       3S7«»
                                                                                                                1ST NCMKT ST1 h|

-------
cr>
Figure 17.  E.P.A. Light Duty Stratified Charge Project.  Task  II Configu-
ration Study.  Category I - V8 Naturally Aspirated TCCS System, Cylinder
Head Drg., Primary Emission Target.
                                                                  SECTION B-B
                                                         PLAN  VIEW
                                                       SECTION AA
VIEW QM CYLINDER
  HEAD  FACE

-------
Figure 18.  E.P.A.  Light Duty Stratified Charge Project.   Task  II  Configu-
ration Study.  Category II - V8 Naturally Aspirated Texaco TCCS System,
Primary Emission Target, Cross Sectional Arrangement,
                                                                             67

-------
   Figure 19.  Calculated Variation in Boost Density Ratio and Air Fuel Ratio

   for the Configurated Turbocharged TCCS Engine.




                           PRIMARY  EMISSION TARGET
     30
  oc


  _i
  ui
  ZJ
     20
      15
        10
20
   ENGINE SPEED - rev/s

30       kQ        50
60

 i
70
             1000
             I      :          I

           2000            3000

                  rev/mfn
                                                                            1.6
                                                                            1.2 t
                                                                                to
                                                                            1.0
68

-------
Figure 20.   Relationship Between Indicated Fuel  Consumption and Air Fuel
Ratio for a  TCCS  Engine.
 280-r0-^-
 270-
 260.
 250.
JC

3s

"  230-
o>
 220'
 210-
 200-
  190-
      -0.38-
            o
            Ll_
            CO
         0.36-
      -0.32-
      L.0.30—
     10         15
                         20
25        30

 A/F RATIO
35
                                                                          69

-------
          Figure 21.   Estimated Performance Curve for 0 96 x 96 mm Turbocharged
          In-line 6 Configuration - Category 2.
          BARE  ENGINE
A.I.T. 2CTC
BARO 760 mm Hg
             PRIMARY  EMISSION  TARGET
              TCCS COMBUSTION SYSTEM
              r»  100
                                        ENGINE SPEEDj - rev/s

                                                   50
          30
                                                                                  .130
                                                                                  • 120
                                                                                      
-------
                          Figure 22.   E.P.A. Light Duty Stratified  Charge Project.   Task  II  Con-
                          figuration  Study.  Category II  -  In-line  6  Turbocharged  TCCS System,
                          Installation Drg:, Primary Emission Target.
HYDRMAIC
                                                                                                                          AOTRNKPR
                                                                                                                 eo^    „._ Sim&
                                                                                                                 sritont   x. »•»
                                                                                                                 BMP     »« ww .
                                                                                                                 BMCP
                                                                                                                 RMAX    71 0 tar
                                                                                                                 CARRC1TV  41C.  I'l
                                                                                                                 BCW VOL   3*t-»
                                                                                                                 CST -^jcm t to k«
                                                                                                                 smoKC
                                                                                                                            • 4000 rpm.
                                                                                                                 •OKVOt   12 2 euft
                                                                                                                 BH WBCHT m > o

-------
ro
                     Figure 23.  E.P.A. Light Duty Stratified Charge  Project.   Task  II Con-
                     figuration Study.  Category II - In-line 6 Turbocharged TCCS  System,
                     Cylinder Head Drg., Primary Emission Target.
                                                                            SECTION  3-B

                                                        PLAN   VIEW
SECTION A-A
VIEW ON  CYLINDER

   HEAD  FACF

-------
Figure 24.  E.P.A. Light Duty Stratified Charge Project.  Task II Con-
figuration Study.  Category II - In-line 6 Turbocharged TCCS System,
Cross-sectional Arrangement, Primary Emission Target.
                                                                        73

-------
            Figure  25.   Estimated  Performance Curve for 2 Bank Rotary Engines
            Category  2.


              BARE ENGINE     A.I.T. 20°C     BARO 760 mm Hg


           PRIMARY EMISSION TARGET    CURTISS WRIGHT COMBUSTION SYSTEM
        100
  130
  120
                                           3000

                                              rev/mi n
1*000
5000
74

-------
                         Figure  26.   E.P.A.  Light Duty Stratified Charge Project.   Task II Con-
                         figuration  Study.   Category  II  - 2 Bank  Rotary, Installation Drg.,
                         Primary  Emission  Target.
01

-------
en
                             Figure  27.   E.P.A.  Light Duty Stratified Charge Project.   Task II Con-
                             figuration  Study.   Category II -  2 Bank Rotary, Cross and Longitudinal
                             Sectional Arrangement,  Primary Emission Target.

-------
Figure 28.  Calculated Variation of Boost Density Ratio for Configurated

Turbocharged TCCS Engine.



           CALCULATED VARIATION OF BOOST DENSITY RATIO FOR


                CONFIGURATED TURBCCHARGED TCCS ENGINE
                      SECONDARY EMISSION TARGET
       1.6 -
     o
    Q.
    a:

    >-
       1.2
       1.0



x
2



/
0 3
l


x

ENGINE !
3 1»C
i

X"
^

PEED - re
) 5
i

^


V/s
0 6(
i

S^


3 7
i i
i 1*1
1000 2000 3000 kOOO
rev/mi n
                                                                            77

-------
Figure 29.   Estimated Performance Curve for 0  101  x 92 mm V8 Turbocharged
Configuration  - Category 2.

  BARE ENGINE        A.I.T. 20°C         BARO 760 ran Hg
  SECONDARY  EMISSION TARGET      TCCS COMBUSTION SYSTEM

       r 140
   180
PERFORMANCE WITH  1U EGR
AND COMBUSTION  RETARD
                               ENGINE SPEED |-  rev/s

                        30       kQ       SO       60
           1000

-------
                        Figure  30.   E.P.A.  Light Duty  Stratified  Charge  Project.   Task II  Con-
                        figuration Study.   Category  II  - V8  Turbocharged TCCS  System, Installa-
                        tion  Drg., Secondary Emission  Target.
AKrtW.JA.TW
                                                                                                                       ao«t    10.--   SAgNTCS

                                                                                                                       BHP    i}5 kv «**-/»»/.
                                                                                                                       BMEP   fr» tar at*lrvil%
                                                                                                                              9O Wr o> 41 rav/t
                                                                                                                       P MMl   7IOte«r
                                                                                                                       OS»*>CITV  S 87  Litres
                                                                                                                       •OK VOL  ••*> -'
                                                                                                                       CST WtWKT 2«« fc.
                                                                                                                              V*-T3tA>   "7^21^
                                                                                                                      STWMC   >b4'      S«I2
                                                                                                                      •KP     «l • *000r»«,
                                                                                                                      WCP     «DlMWf *4000rf^
                                                                                                                              lUiW^* t*»f|«m.
                                                                                                                      PHAX   IO*>iW.«/
                                                                                                                      OMtKfTV  5i»CID
                                                                                                                      •CX^IL  12 I U ft
                                                                                                                              (,X> Ik

-------
       Figure 31.   Estimated Performance Curve for 0 93 x 93 mm V8 Configuration
       Category  3.

                  BARE  ENGINE   A.I.T.  20°C    BARO 760  mm Hg
              PRIMARY  EMISSION  TARGET    MAN-FM  COMBUSTION  SYSTEM
        130
        120-
        30-
                                 2000
3000
4000
                                                                            10.,
                                 ENGINE  SPEED - rev/S
                                       rev/mi n
80

-------
CO
                           Figure 32.  E.P.A.  Light Duty  Stratified Charge Project.   Task II Con-
                           figuration Study.   Category  III  - V8 N/A -  M.A.N. FM System,  Installa-
                           tion  Drg., Primary  Emission  Target.
                  490
                  28-04'
       FUEL INJECTION
           PUMP
                                                                           WATER PUMP
HYDRAULIC PUMP
                                                                                      STARTER
                                                                                       MOTOR
AIM OMPTTKMNNC
    UNIT
           S. I. UNIT*
                                                                                                         torn
                                                                                                                  99 M.
                                                                                                         f. MAX
                                                                                                         CAW*dTY   3-Oft
                                                                                                         •OK VOL.   O-XT7
                                                                                                           MPMlAL  JNTf>
                                                                                                                  > A*.
                                                                                                         ».kJ>
                 » 4000^0
                                                                                                         KMAH
                                                                                                         •OK VOL.
                                                                                                                  ao*
                                                                                                                  » 8
                  29W

-------
00
                          Figure  33.  E.P.A. Light Duty Stratified  Charge Project.  Task II Con-
                          figuration Study.  Category III - V8 Naturally Aspirated M.A.N. FM
                          System,  Primary Emission Target, Cylinder Head Drg.
            PLAN VIEW
SECTION  A-A
VIEW ON  CYLINDER
 HEAD GAS FACE

-------
Figure 34.   E.P.A. Light Duty Stratified Charge Project.  Task II Con-
figuration Study.  Category III - V8 Naturally Aspirated M.A.N. FM
System, Primary Emission Target, Cross Sectional Arrangement.
                                                                              83

-------
             Figure  35.   Estimated  Performance  Curve  for 0 86 x 79 mm Naturally
             Aspirated  V8 Configuration  -  Category 4.

           BARE ENGINE         A.I.T. 20°C                 BARO 760 mm Hg

           PRIMARY AND  SECONDARY EMISSION TARGET     VW COMBUSTION SYSTEM
            r  100
                1000
                                           10-,
2000            3000

      ENGINE SPEED - rev/min
84

-------
                                 Figure  36.   E.P.A.  Light  Duty  Stratified Charge Project.   Task  II Con-
                                 figuration Study.   Category IV - V8  VW System, Installation Drg.,
                                 Primary and  Secondary Emission Target.
                              TC.3
. ,47 SO OS' ^
500*^ 2000 -
114 hi
430" J2lf
rr
^. — rf
¥¥
"--
ll»

!¥¥'



j
±E

_

• ii





         PUMP-
                     Bt
                    _^,44|i-tt^ t
                    -,f~^
                    -Ci
                    	^
730
ears'
                                                                                                                             AIR CONOTICWING
                                                                                                                             UNIT
   FUEL INJECTION
   pgMP
oo
tn
                                                                                              BORE    ah-.ouk&'-UNITS
                                                                                              STROKE   71) m m
                                                                                              BHP     9C.-S KW C 75 rtv/t
                                                                                              9MLP    7-1 tw « 75 r«v/»
                                                                                                     76 bar «  U,  rtutt
                                                                                              f> MAX    » (. bor
                                                                                              CAPIMITV  3'«.7  Litrt*
                                                                                              BOX VOL  2&*~«
                                                                                              EST. Wtl&HT 2SO Kg
                                                                                                                         BORE     S-99-OA
                                                                                                                         STROKE   in      UNITS
                                                                                                                                 IO3 ib/.n* (f)43OOrpm
                                                                                                                                 IIB lb/in>
                                                                                                                         PMAX    860
                                                                                                                                 e24 c i o
                                                                                                                         S» VOt   IQ-O c. ft.
                                                                                                                         EST WtXIHT 55O IB

-------
00
                          Figure 37.   E.P.A.  Light  Duty Stratified Charge Project.   Task  II
                          Configuration Study.   Category IV - V8 VW System, Cylinder Head
                          Drg., Primary and Secondary  Emission Target.
                                                                  PLAN VEW
SECTION A A
VIEW ON CYLINDER
   HEAD F»CE

-------
Figure 38.  E.P.A. Light Duty Stratified Charge Project.  Task II
Configuration Study.  Category IV - V8 VU System, Cross-sectional
Arrangement, Primary and Secondary Emission Target.
                                                                          87

-------
             Figure 39.  Estimated Performance Curve for 0 88 x 88 mm V8 Con-
             figuration - Category 5.
             BARE ENGINE
                   A.I.T.  20UC
                        BARO 760 mm Hg
                PRIMARY EMISSION TARGET   HONDA GVCC COMBUSTION SYSTEM
        130
        120 •
        110
        100
         90
      Q-  80
         70
         60
         50
         40'
         30H
             rioo
              •90
              •80
'60
              •50
                 :s

                  I
                 o
                 0.
              30
       20
        I
                 1000
                                      POWER
            rev/s
30       40        50
60
                                                               10-
70
 I
  2obo            3000

      ENGINE SPEED - rev/min
                                                   4000
                                                                             6.
                                                                    140





                                                                    130



                                                                       CM

                                                                    120 .5

                                                                        «4-
                                                                        JO


                                                                  . 110





                                                                    100





                                                                    90
80
 A
88

-------
 MR
                               Figure 40.   E.P.A. Light Duty Stratified Charge Project.   Task II
                               Configuration  Study.   Category V  -  V8 CVCC System, Installation Drg.,
                               Primary Emission Target.
           . Ill
                          -air
1
ST"





J__
l
T


b
•rar

I^Hj

V '
1^-




1.
*-*»•









J /






!


















i

	 ^










i



1











\
             UNIT
                                                                               J
oo
                                                                                                                            -ALTERNATOR
                                                                                                                  P MAX    SB fc
                                                                                                                  CAPNCJTC  48B
                                                                                                                     VOL  321 -v'
                                                                                                                  ttH P    HO 3 a 4400 r.pn
                                                                                                                         9MI a/n* «4400(.p«.
                                                                                                                         IIS
                                                                                                                        JtOCLO
                                                                                                                  ••KMOL   Il4t.|t
                                                                                                                  C9T VTKXT 9QO I b

-------
               Figure  41.  E.P.A. Light Duty Stratified Charge Project.   Task  II
               Configuration Study.  Category V -  V8  CVCC System, Cylinder  Head
               Layout,  Primary Emission Target.
VIEW ON CYLINDER

  HEAD FACE
SECTION  A A
PLAN  VIEW

-------
Figure 42.  E.P.A. Light Duty Stratified Charge Project.  Task II
Configuration Study.  Category V - V8 CVCC System, Cross-sectional
Arrangement, Primary Emission Target.
                                                                          91

-------
              Figure 43.  Estimated Performance Curve for 0 96 x 96 mm V8 Con-
              figuration - Category 5.

            BARE ENGINE        A.I.T. 20°C        BARO 760 mm Hg
            SECONDARY EMISSION TARGET   HONDA CVCC COMBUSTION SYSTEM
            H30
                               I          I
             	PERFORMANCE WITH  11*  EGR
         k
                                2000
92
                                          rev/min
3000
4000

-------
                            Figure 44.   E.P.A.  Light  Duty  Stratified  Charge Project.   Task  II
                            Configuration  Study.   Category V -  V8 CVCC System,  Installation Drg.,
                            Secondary  Emission  Target.
                                                                                                                              HYDRAULIC PUMP
in
oo
                                                                                                                                      . -ALTERNATOR
                                                                                                                           BORE    94.... D,*  &AJ2HS
                                                                                                                           STHOKE   9fcm «
                                                                                                                           B.H.P    121 KW  4000 rp.
H5 Ib/m' tD ZOOOrpm
85O tw.r1
 J4O c, o
 128  ^ft
                                                                                                                           ESt VD&HT  oOO lb

-------
                                   COST ANALYSIS

      Since  the  literature survey contained little information on production costs
 for  the various  stratified charge engine, an in-house cost estimate was made for
 each  of the engines designed in the configuration study.  The input information
 for  the analysis was obtained from two principle sources,

 1.    Information supplied to Ricardo on a confidential basis by a number of
      European manufacturers of automotive vehicles and associated components
      Including  fuel Injection equipment, carburettors etc.  This information was
      broken down Into costs of major engine mechanical components such as block
      pistons, crankshaft, flywheels, cylinder heads etc.

 2.    Information contained in two surveys by NAS in May, 1973 and September, 1974
      (Ref.  6.32) covering the cost of emission control components.   In some cases,
      the  figures from these two references were adjusted to take account of
      Inflation.

      In deriving the engine costs, no attempt was made to adjust the figures from
 projected sales.   It was simply assumed that equal numbers of the alternative
 engines were being produced, and that the rate of production was of the order of
 50,000 units/year.

      The  reasons behind the choice of the individual figures are given below.

 1.    I tern 1 - 4.  The cost of the engine assembly was basically determined by the
      engine size, although additions were added to the CVCC engine to account for
      the extra valve gear and camshafts.

 2.    I tern 14 and 5.  For many of the engines, the fuelling equipment is a major
      Item.  The  injection pump for each of the engines was considered to have
      equal  production costs, with a small reduction for 6 cylinder engines, and an
      increase for boost control on the turbocharged engines.  The injection equip-
      ment cost of the VW engine was particularly high due to the 12 plunger layout
      and  16 injectors.  Some allowance was made for an alternative arrangement
      usfng  a completely electronic system.  The carburettors of the CVCC engine
      were considered to be 30% more expensive than those of the gasoline engine,
      and the IL-6 gasoline engine was fitted with electronic fuel injection.

 3-   An allowance was also made for control equipment on the throttled fuel
   .   Injected engines, since the throttle must be linked with the fuel injection
      pump,  as well  as a signal for engine speed, from the distributor.  In many
     cases,  these Items must also be linked to the EGR valve.

4.    Item 8.  Since direct Injection stratified charge engines appear to function
     better with long duration, or multi-strike sparks, an allowance was included
     for transistorised Ignition on these engines.

5.    I tern 6.  The cost of exhaust catalysts was determined by the amount of control
      required e.g.  the cost of catalysts for the secondary target TCCS engine was
     twice as high as that for the primary target MAN-FM, reflecting the large
     difference In baseline HC emissions.  Surprisingly, the cost of the thermal
      reactor for the CVCC engines emerged as more expensive than a catalyst,

6.    Item 9.  At the secondary emission target the exhaust gas recirculated to the
      Inlet of the engines, must be modulated according to the engine air flow, and
     often  It must  a.lso be cooled, to reduce the air displacement and heating
     effects in the engine.

 94

-------
7.    Item 10.   Other  emission control  I terns such as evaporative controls,  PCV
     valves,  Intake heaters,  dleseling solenoids etc., were costed separately and
     added together.   The fuel  Injected  engines had considerable advantages in this
     area.

8.    I tern 11.   An  air pump was  Included  on the gasoline engine.

9.    Item 13.   A turbocharger was Included on two TCCS engines.

     Four of  the engines  considered were similar to those costed by NAS in their
January,  1973  report.   The comparison  of results is:-

                       Ricardo                 NAS
                       Estimate               Estimate        Ratio
                       1975 %                 1972 %

Gasoline  V-8            595                    320             1.86
Primary CVCC            600                    300             2.0
101  Diesel              701                    3^3             2.0*»
Rotary                 667 (with carburettor  2~jk             2.k2 (2.0*0
                            560)

     The  rotary engine estimates were  not directly comparable, as the Ricardo con-
figuration had fuel Injection.   The figure in brackets is an alteration to include
a carburettor  rather  than fuel  Injection for comparison purposes.

     The  ratio of  estimates Is  consistent among the different engines, but the
ratio of  2 between the two estimates is  rather high.  Some of the difference can
be accounted  to Inflation, and  the remainder is due to the higher Ricardo estimate
for the basic  engine  assembly.
                                                                                95

-------
vo
en
         POWER PLANT
         V-*GASOUNI



         O* GASOLINE



         P10CO V-»



         PWCOIU6



         PtOCO V-8



         TCCS V-i



         TCCS iu« T/C



         CL'RTIS WRIGHT ROTARY



         TCCS V-» T/C



         M.A.N. r.M. V-»



         T.¥. V-t



         V.W. V-»



         CVCC V-»



         CVCC V-«



         DIESEL V.I
                                                                STRATIFIED   CHARGE  ENGINE  .  FEASIBILITY  STUDY





                                           BAR CHART SHOWING ESTIMATED MANUFACTURING COST BREAKDOWN FOR THt VAMOUS POWER PLANTS . U.S. DOLLARS
                                    I. CYLINDER BLOCK



                                    2. CON-RCDS. CRANKSHAPT. VALVI



                                      GEAR, PirW HEEL, ETC.



                                    3. PISTONS



                                    4. CYLINDER HEAD(S)



                                    S. CONTROL GEAR BETWEEN EGR.



                                      THROTTLE, DISTRIBUTOR AND



                                      INJECTION PUMP



                                    6. MANIFOLDS t HEATING PIPEWORK IH.
 1.  EXHAUST REACTOR AND/OR CATALYST



 I.  IGNITION DISTRIBUTOR, COIL, PLUGS



•».  EGR VALVIt AND PIPEWORK



10.  OTHER EMISSION CONTROL GEAR: EVAP



    CONTROL. P.C.V. INTAKE HEATER,



    TRANSMISSION CONTROLLED SPARK,



    SPARK ADVANCE CONTROL, ANTI



    DIESELING SOLENOID, ETC. ETC.



II.  AIR PUMP
It.  STARTER MOTOR, ALTERNATOR



    VACUUM PUMP, HYDRAULIC PUMP



I).  TURBOCHARGER



H.  CARBURETTOR AND/OR INJECTION



    PUMP, PRIMARY INJECTORS,



    SECONDARY INJECTORS
1 1 2 1 3 1 4 1 S i 7 1 8 1 9 1 tO f II 1 12 1 1* 1
1 I

: 1 I 2 IJ14I6I7II1!
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REDUCED
ElECTNO
COST FOR

-------
                                POWER PLANT RATING

SUMMARY

     The quantitative comparison of different power plants was one of the major aims
of the study.  This section describes the rating methodology which was developed,
how it was applied to the potentially viable power plants and the results of that
applicat ion.

     The rating methodology Involves the identification of performance aspects or
requirements for a power plant.  Each aspect Is given a weighting indicating its
relative importance.  Each power plant is then given a 'rating1  indicating how
well it met the requirements of each performance aspect.   Multiplication of each
'rating1 by the appropriate 'weighting1 and summation of the products then gives a
numerical   'overall rating'.  Comparison of the 'overall ratings'  allows the power
plants to be compared on a numerical basis.

     The individual ratings for each performance aspect for each power plant are
listed and the reasons for these ratings are discussed.

     The 'overall  ratings' Indicate that the rating achieved by the conventional
gasoline engines at primary emission levels can be closely approached by two
stratified charge systems (PROCO and CVCC).  The remaining contenders can be con-
sidered contenders all achieving varying degrees of viability.

     Of the engines configured for the secondary emissions targets, the Honda
CVCC combustion system emerged as the best, closely followed by Ford PROCO and
VW.
                                                                                97

-------
                                POWER PLANT RATING

 INTRODUCTION

      In order to provide a quant!tative assessment of the relative merits of the
 various power plants selected, the major aim of the study was to rate the per-
 formance aspects of each power plant.  The methodology already developed for the
 light duty diesel engine study was considered suitable for this application.  By
 the use of the existing methodology a direct comparison between the assessment
 of the existing power plants and those rated in the earlier survey was possible.
 Those aspects which render a particular power, plant viable or not for a light duty
 application were also identified and quantified.  Furthermore the methodology
 allows an assessment of changes in a particular area as well  as highlighting areas
 worthy of effort to make a particular configuration more suitable for use in a
 given environment.

 Approach of Rating System

      The fitness of any power plant for a given duty is a combination of the
 excellence with which it meets various performance aspects or requirements and the
 relative importance of those individual aspects.  The application of any rating
 system must thus involve five stages:-

 (I)   Identification of performance aspects.

 (2)   Estimation of relative importance of those aspects.

 (3)   Estimation of how well a particular power plant meets a  performance aspect.

 (4)  Assessment of overall merit of that power plant.

 (5)  Comparison with overall merit of other power plants.

 Performance Aspects

     The methodology employed in the light duty diesel  engine study established
 twenty-six performance aspects by which each power plant was  rated.  Each of these
 performance aspects was individually weighted as a measure of Its relative
 importance; the final  score being the product of the rating and the weighting.  For
 the current study the same performance aspects and weightings were employed

     The performance aspects are listed in the following table together with the
weighting factors.

                   Aspect                                   Weighting

     1             Smoke                                       4.48

     2             Particulates                                2.14

     3             Odour                                       4.48

     4             N0x                                         3.92

     5             HC                                           3.99

     6             CO                                           3.61


 98

-------
                   Aspect                                   Weighting

      7             S02                                         3.148

      8             HC reactivity                               1.83

      9             Evaporative  Emissions                       1.60

     10             Miscellaneous  Emissions                     0.98

     11             Noise  (Drive-by)                            6.32

     12             Package volume                             2.61

     13             Package weight                             2.59

     1A             Fuel economy                               12.20

     15             Fuel cost                                   5.1*0

     16             Vehicle first  cost                          l».65

     17             Maintenance cost                            ^.35

     18             Startability                                k.85

     19             Hot drlveability                            4.M5

     20             Cold driveabllity                           3.52

     21             Torque rise                                 1 .98

     22             Durability                                  1».80

     23             Heat loss                                   2.18

     2lt             Fire risk                                   3.55

     25             Idling noise                                3.83

     26             Vibration and  torque recoil                 2.18

      In some of these areas, estimates on the performance of the various engines
had  been made In the configuration study, and the results are summarised in the
summary table of that section.

How Well a Performance Aspect or  Requirement  is Met

      It is necessary that a rating scale be devised so that a quantitative assess-
ment of how well a particular power plant meets a given performance aspect can be
made.  The above list of performance aspects shows that although some aspects could
be quickly assessed In a numerical fashion, many others are essentially qualitative
and any rating scale should be able to cover all aspects.

     As expected, some difficulty was experienced in relating a purely subjective
impression to a linear quantitative scale, but after some consideration the

                                                                                99

-------
following system was adopted as giving the numerical scale easily relatable
subjective key points.  The numbers without definition are an interpolation  of the
su'r round ing merit definitions.
Merit
0
1
2
3
k
5
6
7
8
9
10
Rating Scale
Totally unacceptable

Bad

Poor
Acceptable

Good

Best practical
Perfect
Assessment of OveraM_Mer_t t_pf_the_ Power Plant

     The rating system evolved allows an immediate quantitative assessment of the
overall merit of the power plant and this is accomplished by multiplying each
aspect 'rating1 by its appropriate 'weighting1 and summing all  the products.
With a total weighting of 100 and a merit scale of 0-10 as above the maximum
possible is 1000.

     The relative merit of various power plants can be assessed immediately by
comparing their total scores, the power plant with the highest  score being the
best.  An Idea of the absolute merit of the power plants can also be obtained if
the score is divided by 100 and the quotient related to the above rating scale,
e.g. a score of 1000/100 = 10 is a 'perfect1 power plant.  A score of 500/100 = 5
is an  'acceptable' power plant.

Use of the Rating System In the Study

     In order to apply the rating system to the power plants considered in this
study a committee was used to assess the various ratings.  The  committee consisted
of four experienced members of Rlcardo staff and great care was taken to ensure
that the committee had no bias to either diesel, gasoline or any of the stratified
charge configurations considered in this study.  The power plants considered were
those described in the 'engine configuration1 section of the report with the
addition of the two gasoline engines and the IDI diesel engine  described briefly
in that section.  The engines considered are listed below, together with the
categories In which they are divided and their respective emission targets--

               Engine                         Category     Emission Target

     I          V-8 'American1 Gasoline           -             primary

     2         IL-6 'European1 Gasoline          -             primary

     3         PROCO V-8                         I             primary

     k.        PROCO IL-6                        I             primary

     5         PROCO V-8                         I             secondary

 100

-------
               Engine                         Category    .Emission Target

     6         TCCS V-8                          ||            primary

     7         TCCS  IL-6 T/C                     II            primary

     8         Curtiss-Wright Rotary             II            primary

     9         TCCS V-8 T/C                      I  I            secondary

     10         MAN-FM V-8                        III           primary

     11         VW V-8                            IV            primary

     12         VW V-8                            IV            secondary

     13         CVCC V-8                          V             primary

     14         CVCC V-8                          V             secondary

     15         IDI Diesel V-8                    -              primary

     Each of the power plants above were considered for the emission targets  shown
and  in some cases the secondary target was also considered.  The quantity of
exhaust pollutants for the two target levels are shown below measured according
to the CVS-CH test procedure:-

                              Primary Targets

                              HC         0.41 g/mile
                              CO         3.^ g/mile

                              N0x        1.5 g/mile

                              Secondary Targets

                              HC         0.41 g/mile

                              CO         3.4 g/mile

                              NO         0.4 g/mile

Results of Rating Assessment

     The following rating assessment is sub-divided into 26 sections each corres-
ponding to the 26 performance aspects of the rating system.  The score  allocated
to each of the 15 power plants is shown in a summary table in each section  together
with the weighted rating.

     Each section also contains brief notes on the  derivation of the various  scores.
A complete score table is shown at the end of this  section.
                                                                               101

-------
1.   Smoke  (Weighting 4.48)
     Eng ine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURT ISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   P r i ma ry
   Primary
   Secondary
   P r i ma ry
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
Score

 9
 9
 8.5
 8.5
 8.5
 6
 5.5
 6
 5.5
 6
 8.
 8.
 9
 9
 6
Rating

40.32
40.32
38.08
38.08
38.08
26.88
24.62
26.88
24.64
26.88
38.08
38.08
40.32
40.32
26.88
     The absolute smoke limit at which an engine is limited varies  considerably
from country to country and even between manufacturers,  some simply complying
with legislative requirements and others aiming for significantly lower levels.
For passenger car use, maximum,smoke levels must be selected on an  aesthetic basis
In order to avoid public criticism.   From European experience,  Ricardo would
recommend that maximum steady state  smoke levels of 5-8% opacity should be aimed
for.  The combination of these low .smoke levels with the high power/weight ratio
of the vehicle should result in the  exhaust being at least acceptable from the
candidate power plants.  However, the stratified charge  engines vary from category
to category in their smoke limited performance.

     In rating the conventional gasoline engines with a  score of 9  (the best
practical), It was considered that no significant quantity of smoke was emitted:
this also being applicable to the CVCC engines in category V, where the fuel supply
is carburetted.  The PROCO engines have low smoke levels due to the early fuel
injection (Score 8.5).  Similarly the VW engines were rated good (8.5).  The TCCS,
MAN-FM and Rotary engines were considered to have similar smoke characteristics to
the diesel engine and were rated accordingly; the two turbocharged  TCCS engines
being down graded i a point due to the need to employ boost controlled fuel
Injection pumps.
2.   Particulates  (Weighting 2.14)
     Engine

     V-8  GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURTISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
Emission Target

   Primary
   Primary
   Primary
   Primary
  •Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
Score

 7
 7
 6.5
 6.5
 6.5
 3
 3
 3
 3
 3
 7
Rating
14.98
14.98
13-91
13:91
13.91
6.42
6.42
6.42
6.42
6.42
14.98
102

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     Engine                    Emission Target            Score          Rating

     VW V-8                       Secondary                7             IMS
     CVCC V-8                     Primary                  7             I1*.98
     CVCC V-8                     Secondary                7             I1*.98
     DIESEL V-8                   Primary                  2             *».28

     Current data Is still insufficient to come to a final conclusion concerning
this topic.  With a lack of standards to judge by the conventional  gasoline engine
running on lead free fuel must be considered good; worthy of seven  points,  and  the
diesel, with levels of 10 times as high, was considered bad, wi\h a score of two
points.  With the limited data available, Ricardo feel confident to predict the
stratified charge engine particulate levels In terms of those already known.   It
was considered therefore that the VW and CVCC engines would have similar levels  to
those of the conventional gasoline engines as they have similar combustion
characteristics (Score 7), and the TCCS, MAN-FM and Rotary engines  approach the
level of the diesel (Score 3).  There Is some evidence to indicate  that the PROCO
particulate levels may be twice that of the conventional gasoline engine; but still
good (Score 6.5).

     If particulate levels are to be the subject of legislation, the lower rated
engines would need after treatment in the form of particulate filters and in this
area further work would have to be carried out.

3.   Odour(Weight ing k.kB)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  6             26.88
     IL-6 GASOLINE                Primary                  6             26.88
     PROCO V-8                    Primary                  6             26.88
     PROCO IL-6                   Primary                  6             26.88
     PROCO V-8                    Secondary                6             26.88
     TCCS V-8                     Primary                  A.5           20.16
     TCCS  IL-6 T/C                Primary                  *t.5           20.16
     CURTISS-WRIGHT ROTARY        Primary                  *».0           17.92
     TCCS V-8 T/C                 Secondary                A. 5           20.16
     MAN-FM V-8                   Primary                  3-0           13.M
     VW V-8                       Primary                  5.0           22.k
     VW V-8                       Secondary                5-0           22. ^
     CVCC V-8                     Primary                  6.0           26.88
     CVCC V-8                     Secondary                6.0           26.88
     DIESEL V-8                   Primary                  *f.O           17-92

     It was generally agreed  that the conventional gasoline power  plants are good
from the point of view of odour but were down graded  1 point to  6  on the grounds
that with a cold engine and using catalyst, some  problems arose.   The PROCO engines
were reported to be good on odour and were awarded the same score  as were  the CVCC
engines.  The diesel engine  is known to be relatively poor  in  this respect and was
awarded k points.  The MAN-FM power plant, known  to have  an odour  problem, was
awarded 3 points.  The VW engines were considered to  be acceptable (5 points)
although little data was available and  the TCCS were  rated marginally better than
the diesel at k.S points.  The Rotary engine  Is also  known  to  have an odour problem
(awarded *» points) due to poor scavenging of  end  spaces and poor surface to
vp1ume ratio.
                                                                               103

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     NO  (Weighting 3-92)
       /C

     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURT ISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
Score

 5
 5
 5
 5
 5
 6
 6
 7
 5
 7
 7
 5
 5
 5
 5
Rat i nq

19.6
19.6
19.6
19.6
19.6
23.52
23.52
27.kk
19-60
27. M
27.kk
19.6
19.6
19.6
19.6
     With this performance aspect and with all  the others  Involving  legislative
requirements it was assumed that all  the power  plants  selected  for  rating  could
at  least achieve the levels required  by such legislation.   Where  the legal  require-
ments were just met, with or without  treatment, an acceptable  rating was  scored
and  if any margin was available, with or without aid,  an additional  one or two
points were awarded.  Thus the score  table shows the majority of  the power plants
being able to achieve the 1.5 g/mile  NO  level  during  the  CVS-CH  cycle with a
score of 5 points, the remainder of the engines having a better score.  All  the
power plants entered for the secondary level of NO  (.k g/mile) achieved  a merit
rating of 5 points.
5.   HC(Welghting 3-99)

     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PRQCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURTISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   P r i ma ry
   Secondary
   Primary
Score

 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
Rating

19.95
19.95
19.95
19.95
19.95
19.95
19.95
19.95
19.95
19.95
19-95
19-95
19.95
19.95
19-95
     In this performance aspect all the power plants were considered capable of
achieving an acceptable level of HC during the CVS-CH cycle.   No particular engine
stood out as'superior to the rest so all  achieved a merit rating of 5 points.
  104

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6.    CO Weighting 3.61)

     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURTISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   Primary
   Pr imary
   Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
Score

 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 6
Rating

18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
18.05
21.66
     Here again all the engines were expected to achieve an acceptable level  of  CO
with the diesel awarded an extra point because of its ability to achieve low levels
without treatment
7.   S02(Weighting 3.*»8)

     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURTISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     Diesel V-8
Emission Target

   Primary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   P r i ma ry
Score

 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 5
 2
Rating
 17.*»
 17.*
 17.A
 17.1*
 17.1*
 17.1*
 17.1*
 17. k
 17.1*
 17. k
 17.1*
 17. k
 17.1*
 17. k
 6.96
     This pollutant  is  totally dependent on  the sulphur content of the fuel and the
amount of fuel being burnt.   In assessing  the diesel for SO-  it was assumed that
the sulphur content of  U.S.  light distillate (DF  1)  is similar to that found in
Europe (i.e. 0.2 - 0.5%).   In theory  the sulphur  can be completely extracted from
the fuel  but economic considerations  have  ruled this out to date.  The sulphur
content of gasoline  is  very  low  (
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8.   HC Reactivity (Weighting 1.83)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  5             9-15
     IL-6 GASOLINE                Primary                  5             9-15
     PROCO V-8                    Primary                  7             12.81
     PROCO  IL-6                   Primary                  7             12.81
     PROCO V-8                    Secondary                7             12.81
     TCCS V-8                     Primary                  7             12.81
     TCCS IL-6 T/C                Primary                  7             12.81
     CURTISS-WRIGHT ROTARY        Primary                  7             12.81
     TCCS V-8 T/C                 Secondary                7             12.81
     MAN-FM V-8                   Primary                  7             12.81
     VW V-8                       Primary                  5             9.15
     VW V-8                       Secondary                5             9.15
     CVCC V-8                     Primary                  5             9-15
     CVCC V-8                     Secondary                5             9.15
     DIESEL V-8                   Primary                  7             12.81

     This subject  Is an important aspect of HC emissions and it has been demon-
strated that HC  reactivity from the conventional gasoline engine is 10 times
higher than from the dlesel.  Thus ft was assumed that all the power plants with
gasoline engine  characteristics, i.e. VW, CVCC and the two conventional engines
should be awarded  5 points as acceptable and the remainder having dlesel com-
bustion characteristics to some degree should merit an award of 7 points.

9-   Evaporative Emissions(Weighting 1.60)

     Eng'ine                    Emission Target            Score          Rating

     V-8 Gasoline                 Primary                  5.0           8.00
     IL-6 Gasoline                Primary                  5-5           8.80
     PROCO V-8                    Primary                  5-5           8.80
     PROCO IL-6                   Primary                  5.5           8.80
     PROCO V-8                    Secondary                5.5           8.80
     TCCS V-8                     Primary                  5.5           8.80
     TCCS IL-6 T/C                Primary                  5.5           8.80
     CURTISS-WRIGHT ROTARY        Primary                  5.5           8.80
     TCCS V-8 T/C                 Secondary                5.5           8.80
     MAN-FM V-8                   Primary                  5.5           8.80
     VW V-8                       Primary                  5-5           8.80
     VW V-8                       Secondary                5.5           8.80
     CVCC V-8                     Primary                  5.0           8,00
     CVCC V-8                     Secondary                5.0           8.00
     DIESEL  V-8                   Primary                  7.0           H-2

     With modern control systems using carbon filter/storage canisters, gasoline Is
an acceptable and practical fuel, which when considered in relation to the power
plants having carburettors warrants them 5 points.  The power plants using
gasoline injection, i.e. all but the CVCC and V-8 conventional gasoline, were each
awarded an extra i point as It was considered an injection system could achieve
a slightly lower evaporation loss level.

     Mid distillates such as used in high speed diesel engines would suffer only
marginal  evaporative losses and must merit a good rating  (Score 7).

  106

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 10.   Miscellaneous  Emtssfons(Weight ing 0.98)

      Engine                    Emission Target            Score          Rating

      V-8  GASOLINE                 Primary                  5             4.9
      IL-6 GASOLINE                Primary                  5             4.9
      PROCO V-8                    Primary                  5             4.9
      PROCO  IL-6                   Primary                  5             4.9
      PROCO V-8                    Secondary                5             4.9
      TCCS V-8                     Primary                  5             A.9
      TCCS IL-6 T/C                Primary                  5             4.9
      CURTISS-WRIGHT ROTARY        Primary                  5             A.9
      TCCS V-8 T/C                 Secondary                5             4.9
      MAN-FM V-8                   Primary                  5             4.9
      VW V-8                       Primary                  5             4.9
      VW V-8                       Secondary                5             4.9
      CVCC V-8                     Primary                  5             4.9
      CVCC V-8                     Secondary                5             4.9
      DIESEL V-8                   Primary                  5             4.9

      At the time of writing of the study none of the power plants was regarded as
 producing major quantities of any pollutants other than those already considered
 so that all were rated as equal and acceptable.

 11.   Noise  (Drive-by)( Weighting 6.32 )

      The  notse level of a particular engine  is largely dependent on the cylinder
 bore  size, the rotational speed and the rate of cylinder pressure rise.  A 1590 kg
 passenger car powered by a conventional V-8 gasoline engine can achieve a drive-by
 noise level of 71 dB(A) measured at 50 ft.  This level was rated good and awarded
 seven merit points.  The table below shows predicted noise levels for a similar
 vehicle powered by  the remaining power plants, assessed In relation to the above
 parameters together with the merit rating and weighted score.

      Engine                 Emission Target   Predicted      Score       Rating
                                            Vehicle Noise
                                                dBA

      V-8  GASOLINE                 Primary       71            7          44.24
      IL-6 GASOLINE                Primary       73            6.5        41.08
      PROCO V-8                    Primary       71            7          44.24
      PROCO  IL-6                   Primary       75            5          31.60
      PROCO V-8                    Secondary     72.5          6.5        41.08
      TCCS V-8                     Primary       70.5          7.5        47.4
      TCCS IL-6 T/C                Primary       71            7          44.24
      CURTISS-WRIGHT ROTARY        Primary       71            7          44.24
      TCCS V-8 T/C                 Secondary     72.5          6.5        41.08
      MAN-FM V-8                   Primary       72            7          44.24
      VW V-8                       Primary       73            6.5        41.08
      VW V-8                       Secondary     73            6.5        41.08
      CVCC V-8                     Primary       73            6.5        41.08
      CVCC V-8                     Secondary     73            6-5        41.08
      DIESEL V-8                   Primary       74            5.5        34.76

      Changes to engine configuration such as more advanced crank-case design may
modify these predictions and the power plants having the most severe noise problem
are likely to benefit most from such modification.

                                                                               107

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 12.  Package Volume (Weighting 2.61)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  7             18.2?
     IL-6 GASOLINE                Primary                  7             18.27
     PROCO V-8                    Primary                  7             18.27
     PROCO  IL-6                   Primary                  5             13-05
     PROCO V-8                    Secondary                6             15.66
     TCCS V-8                     Primary                  5             13-05
     TCCS IL-6 T/C                Primary                  4             10. 44
     CURTISS-WRIGHT ROTARY        Primary                  9             23.49
     TCCS V-8 T/C                 Secondary                4.5            U -75
     MAN-FM V-8                   Primary                  6             15-66
     VW V-8                       Primary                  7             18.27
     VW V-8                       Secondary                7             18.27
     CVCC V-8                     Primary                  6             15.66
     CVCC V-8                     Secondary                4.5            11.75
     DIESEL V-8                   Primary                  5-5            14.36

     Box volumes as calculated during the configuration phase of  the study are
 Iisted below:-

     Engine                    Emission Target             ft            m

     PROCO V-8                    Primary                   9-7          -275
     PROCO  IL-6                   Primary                  11.9          -337
     PROCO V-8                    Secondary                10.7          -303
     TCCS V-8                     Primary                  11.9 '         -337
     TCCS IL-6 T/C                Primary                  12.2          .346
     CURTISS-WRIGHT ROTARY        Primary                   8.5          .24
     TCCS V-8 T/C                 Secondary                12.1           .343
     MAN-FM V-8                   Primary                  10.83          -307
     W V-8                       Primary                  10.0          .284
     VW V-8                       Secondary                10.0          .284
     CVCC V-8                     Primary                  11.4          .322
     CVCC V-8                     Secondary                12.8          .362
     DIESEL V-8                   Primary                  11.3          -320

     All-are given merit ratings according to their calculated  box volumes based on
a rating  of good for the conventional gasoline engines.   Taken  into account  In the
rating was the length of the six cylinder In-line engines as this  was believed to
be important to safety regulations.

13.   Package Welght(We!ght1ng 2.59)

     Engine                    Emission Target            Score          Rating

     V-8  GASOLINE                 Primary                  6             15.54
     IL-6 GASOLINE                Primary                  7             18.13
     PROCO V-8                    Primary                  6             15-54
     PROCO IL-6                   Primary                  6             15.54
     PROCO V-8                    Secondary                6             15-54
     TCCS V-8                     Primary                  5.5            14.25
     TCCS IL-6 T/C                Primary                  6             15.54
     CURTISS-WRIGHT ROTARY        Primary                  8             20.72

  10R

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     Engine                    Emission Target            Score          Rating

     TCCS V-8 T/C                 Secondary                5             12.95
     MAN-FM V-8                   Primary                  5             12.95
     VW V-8                       Primary                  6             15.5^
     VW V-8                       Secondary                6             15-5^
     CVCC V-8                     Primary                  6             15-51*
     CVCC V-8                     Secondary                5-5          1^.25
     DIESEL V-8                   Primary  '                k.5          11.66

     The following table shows the estimated weight for each  of  the  power  plants
considered In this study.  If the six-cylinder European type  gasoline engine  is
considered to have a rating of good (Score 7) all the remainder,  apart from the
rotary engine, bear a weight penalty and were thus accorded lower scores.

                                                           1 b .          kg .
     V-8 GASOLINE
     IL-6 GASOLINE                                         i»50           20*»
     PROCO V-8                                             551           250
     PROCO IL-6                                            580           263
     PROCO V-8  Secondary                                  571           259
     TCCS V-8                                              602           273
     TCCS IL-6 T/C                                         573           260
     ROTARY                                                330           150
     TCCS V-8 T/C  Secondary                               631           286
     MAN-FM V-8                                            662           300
     VW V-8                                                550           250
     VW V-8  Secondary                                     550           250
     CVCC V-8                                              550           250
     CVCC V-8  Secondary                                   602           273
     DIESEL                                                700           320

\k.  Fuel Economy (Weighting 12.2)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  6.5           79.3
     IL-6 GASOLINE                Primary                  7             85. *»
     PROCO V-8                    Primary                  7-5           91.5
     PROCO IL-6                   Primary                  7-5           91.5
     PROCO V-8                    Secondary                6.5           79-3
     TCCS V-8                     Primary                  7-0           85. ^
     TCCS IL-6 T/C                Primary                  7-0           85. *t
     CURTISS-WRIGHT ROTARY        Primary                  5-5           67.1
     TCCS V-8 T/C                 Secondary                5-5           67.1
     MAN-FM V-8                   Primary                  7-5           91.5
     VW V-8                       Primary                  6.5           79-3
     VW V-8                       Secondary                6.0           73-2
     CVCC V-8                     Primary                  6.5           79-3
     CVCC V-8                     Secondary                6.0           73.2
     DIESEL V-8                   Primary                  8.5          103-7

     This section was considered  the most  important and was awarded the highest
weighting factor.  The definitions of  the  various fuel consumption ratings were
changed from the  previous diesel  survey to the scale shown below as it was con-
                                                                               109

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sidered that 25 mpg, rated 9 points in the earlier study, was impossible to
achieve, with gasoline as the fuel.

          Fuel Economy mpg.               1/100 km         Rating

                                                           0  (totally unacceptable)
               5.25                        M.81            1
                                                           2  (bad)
               8.75                        26.89            3
                                               .            *t  (poor)
              13-125                       17-92            5  (acceptable)
                                                           6
              17-5                         13. V»            7  (good)
                                                           8
              21.87                        10.76            9  (best  practical)
                                                          10  (perfect)

     Predicted fuel economy levels for a 1590 kg  passenger car  were  based on
estimated and measured fuel consumptions from each of the power plants.   The six
cylinder European gasoline engine, with injected  fuel,  was given a good  rating
(7 points) and several  of the stratified charge systems were rated as good or
better.  The dlesel was considered to be almost 'best practical'  and awarded 8£
points.  Of course, the dlesel  engine had an advantage in this  respect since the
fuel economies are rated on a volumetric basis, and dlesel  fuel  has  a higher
specific gravity.  A full list  of the estimated fuel  consumption and economy levels
obtainable during the CVS-CH test cycle are as  follows:-

                                          1/100 km         mpg

     V-8 GASOLINE                          14.6            16
     IL-6 GASOLINE                         13.5            17.*»
     PROCO V-8                             12.5            18.7
     PROCO IL-6                            12.75            18.A
     PROCO V-8  Secondary                  \k.2            16.5
     TCCS V-8                              13.8            17.0
     TCCS IL-6 T/C                         13.8            17-0
     ROTARY                                16.75            1**.0
     TCCS V-8 T/C  Secondary             .  16.75            14.0
     MAN-FM V-8                            12.3            19.0
     VW V-8                                14.2            16.5
     VW V-8 Secondary                      15.13            15-5
     CVCC V-8                              13.95            16.8
     CVCC V-8  Secondary                   15.6            15.0
     DIESEL V-8                            11.0            21.0

15-   Fuel  Cost(Weighting 5.40)

     Engine                    Emission Target             Score          Rating

     V-8 GASOLINE                 Primary                  5             27.0
     IL-6 GASOLINE                Primary                  5             27.0
     PROCO V-8                    Primary                  5             27.0
     PROCO IL-6                   Primary                  5             27-0
     PROCO V-8                    Secondary                5             27.0
     TCCS V-8                     Primary                  5             27.0
     TCCS IL-6 T/C                Primary                  5             27.0


110

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     Engine
Emission Target
Score
Rating
     CURTISS-WRIGHT  ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
 5
 5
 5
 5
 5
 5
 5
 6
27-0
27.0
27-0
27.0
27.0
27.0
27.0
32. 4
     In spite of the trend towards higher fuel costs It was assumed that  the
situation for all the power plants employing gasoline as fuel  must rate as
acceptable.  All these engines were required to run on lead free fuel  to  preserve
catalyst life, with the exception of the CVCC engine which, having thermal
reactors, could tolerate  leaded fuel.  This factor however, was not considered
to constitute a measurable advantage to the CVCC power plants.  The diesel  engine
was awarded 1 extra point  (Score 6) as the light distillate fuel (DF 1) has a
currently lower price at  the pump although this may always be subject  to
artificial manipulation by taxation.
16.  Vehicle First Cost(Weight!ng 4.65)
     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURTISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
Score

 6
 6
 4.5
 5.5
 4.0
 4.0
 4.0
 5.0
 2.5
 4.5
 3-5
 3.0
 6.0
 5.0
 5.0
Rating

27.9
27.9
20.93
25.57
18.
18.
18
,6
,6
,6
23-25
11.63
20.93
16.28
13.95
27.90
23.25
23.25
     It Is estimated that for a conventional V-8 powered passenger car the power
plant is responsible for 25% of the total vehicle cost and the first cost of such
a vehicle was rated as better than acceptable (Score 6).  For this aspect the man-
ufacturing cost  of each power plant was estimated and rated accordingly.  The
following table shows the cost estimates for each engine and It can be seen that
apart from the primary target of the CVCC all the power plants Incur a cost penalty
in relation to the conventional gasoline engines; the TCCS secondary engine and
the two VW engines being between 40 and 65% more expensive.
     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
                  Manufacturing Cost

                     %  595
                        598
                        741
                        664
                                                                              in

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                                                  Manufacturing  Cost

     PROCO V-8  Secondary                            %  827
     TCCS V-8                                           811
     TCCS IL-6 T/C                                      827
     ROTARY                                             667
     TCCS V-8 T/C  Secondary                            985
     MAN-FM V-8                                         756
     VW V-8                                             8M *
     VW V-8  Secondary                                  899 *
     CVCC V-8                                           600
     CVCC V-8  Secondary                                670
     DIESEL V-8                                         701

     * Deduct approx. % 80 for electronic fuel  Injection.

     The merit rating for costs was based on the following:-

               Cost %                                  Score

                                                         0
                                                         1
                1000                                     2   (bad)
                 900                                     3
                 800                                     k   (poor)
                 700                                     5   (acceptable)
                 600                                     6
                 500                                     7   (good)
                 itOO                                     8
                                                         9
                                                        10

17.  Maintenance Cost( Weight ing *».35 )

     Engine                    Emission Target             Score           Rating

     V-8 GASOLINE                 Primary                  5             21.75
     IL-6 GASOLINE                Primary                  5             21.75
     PROCO V-8                    Primary                  *».5           19-57
     PROCO IL-6                   Primary                  k.S           19-57
     PROCO V-8                    Secondary                3.0           13-05
     TCCS V-8                     Primary                  3.0           13-05
     TCCS IL-6 T/C                Primary                  3-0           13.05
     CURTISS-WRIGHT ROTARY        Primary                  2.5           10.88
     TCCS V-8 T/C                 Secondary                3.0           13.05
     MAN-FM V-8                   Primary                  k.O           17-40
     VWV-8                       Primary                  1».0           17-^0
     VW V-8                       Secondary                3.0           13-05
     CVCC V-8                     Primary                  6.0           26.10
     CVCC V-8                     Secondary                5-5           23-93
     DIESEL V-8                   Primary                  6.0           26.10

     Maintenance costs for conventional gasoline engines are regarded as  satis-
factory and experience suggests that the diesel  should be better and  was  rated
one point higher (Score 6).  The remaining stratified charge engines  were rated less
than acceptable mainly because of the high cost  of catalytic exhaust  systems, the


112

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exceptions being the CVCC engines which were rated as better than the conventional
gasoline.

     The rotary engine was rated particularly lowly (2.5 points)  because  apart  from
catalysts It was considered the engine may require more than average  mechanical
attention.

18.  Star-tab!! ity(Weighting A.85)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  7             33-95
     IL-6 GASOLINE                Primary                  7             33-95
     PROCO V-8                    Primary   "              7             33.95
     PROCO IL-6                   Primary                  7             33-95
     PROCO V-8                    Secondary                7             33-95
     TCCS V-8                     Primary                  8             38.80
     TCCS IL-6 T/C                Primary                  8             38.80
     CURTISS-WRIGHT ROTARY        Primary                  5             2k.25
     TCCS V-8 T/C                 Secondary                8             38.80
     MAN-FM V-8                   Primary                  7             33.95
     VW V-8                       Primary                  6             29.10
     VW V-8                       Secondary                6             29-10
     CVCC V-8                     Primary                  6.5           31-53
     CVCC V-8                     Secondary                6.5           31-53
     DIESEL V-8                   Primary                  5             24.25

     With the ability to start instantaneously under most environmental  conditions
experienced In America the conventional gasoline engines should merit a  very high
rating but the hot starting of low emissions vehicles can be poor, and Is not
likely to improve substantially beyond today's levels.  However both versions of
the conventional engines were rated good and awarded seven points.  At the other
end of the range the diesel was rated only as acceptable, largely due to the delay
In cold starting due to the heater plug lead time required, and the rotary engine,
known to be a sometimes doubtful starter, was also rated acceptable.  VW and CVCC
engines were rated just below the conventional engines and the TCCS engines were
rated very good (Score 8).

19.  Hot Drlveablllty(WeIghtlng 4.48)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  8             35.84
     IL-6 GASOLINE                Primary                  8             35.84
     PROCO V-8                    Primary                  8             35.84
     PROCO IL-6                   Primary                  8             35.84
     PROCO V-8                    Secondary                8             35-84
     TCCS V-8                     Primary                  8             35.84
     TCCS IL-6 T/C                Primary                  7             31-36
     CURTISS-WRIGHT ROTARY        Primary                  7             31-36
     TCCS V-8 T/C                 Secondary                7             31.36
     MAN-FM V-8                   Primary                  8             35-84
     VW V-8                       Primary                  8             35-84
     VW V-8                       Secondary                8             35.84
     CVCC V-8                     Primary                  7             31-36
     CVCC V-8                     Secondary                5             22.40
     DIESEL V-8                   Primary                  7             31-36

                                                                               113

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      Hot driveabllity of  the conventional gasoline engines was rated at 8 points;
 better  than good, almost  best practical, and all but one of the remaining power
 plants  was rated as good  or better.  The exception was the CVCC secondary emissions
 target  engine which, because of a high degree of EGR required, was considered to be
 just  acceptable  (Score  5).

 20.   Cold Drlveabllity Weighting 3.52)

      Engine                    Emission Target            Score          Rating

      V-8 GASOLINE                 Primary                  k             14.08
      IL-6 GASOLINE                Primary                  6             21.12
      PROCO V-8                    Primary                  7             2k.64
      PROCO  IL-6                   Primary                  7             2k.6k
      PROCO V-8                    Secondary                7             24.64
      TCCS V-8                     Primary                  7             24.64
      TCCS  IL-6 T/C                Primary                  6             21.12
      CURTISS-WRIGHT ROTARY        Primary                  6             21.12
      TCCS V-8 T/C                 Secondary                6             21.12
      MAN-FM V-8                   Primary                  7             2k.64
      VW V-8                       Primary                  7             24.64
      VW V-8                       Secondary                7             2k.6k
      CVCC V-8                     Primary                  4             14.08
      CVCC V-8                     Secondary                k             14.08
      DIESEL V-8                   Primary                  7             24.64

      With flat spots due  to carburation problems at cold temperatures the V-8
 conventional gasoline engine was regarded as poor (4 points).   With gasoline
 Injection the remaining power plants were rated up to good (scoring 6 or 7) with a
 rating  of good for the diesel engine.  The two CVCC candidates, being carburetted,
 were  rated as poor for  the same reasons as the conventional  gasoline engine.

 21.   Torque Back-up (Weighting 1.98)

      Engine                    Emission Target            Score          Rating

      V-8 GASOLINE                 Primary                  7             13.86
      IL-6 GASOLINE                Primary                  6.5           12.87
      PROCO V-8                    Primary                  6.5           12.87
      PROCO IL-6                   Primary                  7             13.86
      PROCO V-8                    Secondary                5             9-90
      TCCS V-8                     Primary                  7             13.86
      TCCS IL-6 T/C                Primary                  5.5           10.89
      CURTISS-WRIGHT ROTARY        Primary                  6             11.88
      TCCS V-8 T/C                 Secondary                6.5           12.87
      MAN-FM V-8                   Primary                  7             13.86
     VW V-8                       Primary                  k             7-92
     VW V-8                       Secondary                k             7.92
      CVCC V-8                     Primary                  7             13.86
      CVCC V-8                     Secondary                6.5           12.87
     DIESEL V-8                   Primary                  7             13.86

     All the. power plants varied in the amount of torque back-up available.  Those
considered good (7 points) having 25% torque back-up, were the V-8 conventional
gasoline engine,  the PROCO IL-6, TCCS and CVCC primary V-8 engines, the MAN-FM and
the diesel  engine.   Marginally inferior were the IL-6 gasoline, PROCO V-8 primary;


  114

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TCCS and CVCC secondary engines each having about 20% torque back-up  (Score 6.5).
The remainder were satisfactory or better with the exception of  the VW engines
which have a curious torque curve with less than ]Q% back-up and were consequently
rated poor with a score of k.

22.  Durability  (Weighting 4.80)

     Engine                    Emission Target            Score           Rating

     V-8 GASOLINE                 Primary                  5             2k.0
     IL-6 GASOLINE                Primary                  5             2A.O
     PROCO V-8                    Primary                  k.5           21.60
     PROCO IL-6                   Primary                  k.$           21.60
     PROCO V-8                    Secondary                3             H».l»0
     TCCS V-8                     Primary                  3             l^O
     TCCS IL-6 T/C                Primary                  3             Ht.^O
     CURTISS-WRIGHT ROTARY        Primary                  2.5           12.00
     TCCS V-8 T/C                 Secondary                2.5           12.00
     MAN-FM V-8                   Primary                  k.5           21.60
     VW V-8                       Primary                  1»             19.20
     VW V-8                       Secondary                3         H».l»0
     CVCC V-8                     Primary                  7             33.60
     CVCC V-8                     Secondary                6.5           31.20
     DIESEL V-8                   Primary                  7             33.60

     Apart from reservations concerning the Rotary engine It was considered that
all the power plants could achieve  100,000 miles mechanically without difficulty.
However, the limitation was expected to be in the catalytic exhaust systems.
Although attempts to Improve catalyst  life have so far not been particularly
successful the durability of the conventional gasoline engines was considered
to be acceptable.  On this basis the remaining engines were judged with the diesel
and CVCC power plants achieving the highest rating as no catalysts are involved.
The remaining power plants all received lower than acceptable ratings, according
to the severity of the demand on the catalysts.  The TCCS secondary emissions
engine and the Rotary engine only rated a score of 2.5 points due to mechanical
as well as other doubts.

23.  Heat Loss (Weighting 2.18)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  7             15.26
     IL-6 GASOLINE                Primary                  7             15.26
     PROCO V-8                    Primary                  7             15.26
     PROCO IL-6                   Primary                  7             15.26
     PROCO V-8                    Secondary                7             15.26
     TCCS V-8                     Primary                  5             10.90
     TCCS IL-6 T/C                Primary                  5             10.90
     CURTISS-WRIGHT ROTARY        Primary                  6             13-08
     TCCS V-8 T/C                 Secondary                7             15.26
     MAN-FM V-8                   Primary                  5             10-90
     VW V-8                       Primary                  7             15.26
     VW V-8                       Secondary                7             15.26
     CVCC V-8                     Primary                  6             13-08
     CVCC V-8                     Secondary                6             13.08
     DIESEL V-8                   Primary                  5             10.90


                                                                              115

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     For this aspect, the vehicle configuration for the various power plants was
assumed to contain an adequate cooling system a 1 lowing for the increased coolant
heat losses for some of the engines at full load.   It is know, for  instance, that
the diesel engine may reject 25% more heat to the  radiator than the equivalent
gasoline engine and that some of the stratified charge engines will  also have a
higher full load heat rejection than conventional  gasoline engines.   The rating
in this section, therefore, was mainly concerned with light load and idle heat
rejection to enable the vehicle interior heating  to be accomplished satisfactorily.

     In this respect all the power plants were awarded 'good'  ratings except for
the diesel, the two primary TCCS engine and the MAN-FM engine, all  known to have low
heat losses at Idle.  These latter engines were however considered  satisfactory
and awarded 5 points.

2k.  Fire Risk (Weighting 3-55)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  5             17-75
     IL-6 GASOLINE                Primary                  5             17-75
     PROCO V-8                    Primary                  5             17.75
     PROCO IL-6                   Primary                  5             17-75
     PROCO V-8                    Secondary                5             17-75
     TCCS V-8                     Primary                  5             17-75
     TCCS IL-6 T/C                Primary                  5             17-75
     CURTISS-WRIGHT ROTARY        Primary                  5             17-75
     TCCS V-8 T/C                 Secondary                5             17-75
     MAN-FM V-8                   Primary                  5             17.75
     VW V-8                       Primary                  5             17-75
     VW V-8                       Secondary                5             17-75
     CVCC V-8                     Primary                  k.S           15-98
     CVCC V-8                     Secondary                4.5           15-98
     DIESEL V-8                   Primary                  6             21.30

     Apart from the diesel engine all the power plants considered in this survey use
gasoline fuel which, due to its high volatility, can contribute to  fire risk.  It
was assumed for the purposes of this rating system that most of these gasoline
powered vehicles would rate as acceptable.  However,  the CVCC engines, with their
high heat capacity thermal reactors might contribute a marginally higher risk and
were therefore down-graded £ a point to k.$.   The  diesel engine was given one more
point (Score 6) as the relatively low volatility of the fuel  was considered to
contain a lower degree of risk.

25.  Idling Noise (Weighting 3.83)

     Engine                    Emission Target            Score          Rating

     V-8 GASOLINE                 Primary                  8             30.6*4
     IL-6 GASOLINE                Primary                  8             30.64
     PROCO V-8                    Primary                  5-5           21.07
     PROCO IL-6                   Primary                  5             19.15
     PROCO V-8                    Secondary                5             19.15
     TCCS V-8                     Primary                  5             19-15
     TCCS IL-6 T/C                Primary                  5             19-15
     CURTISS-WRIGHT ROTARY        Primary                  7             26.81
     TCCS V-8 T/C                 Secondary                k.$           17.24


  ns

-------
     Engine
Emission Target
Score
Rating
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
   Primary
   Primary
   Secondary
   P rI ma ry
   Secondary
   Primary
 5
 6
 6
 8
 8
19.15
22.98
22.98
30.6A
30.61*
15.32
     Idle noise of the conventional gasoline engine is low in terms of both
objectionabi11ty and overall noise level and must approach the best practical  level
that a power plant can achieve.  The CVCC engine, having similar combustion
characteristics at idle, must also rate highly.  All score 8 points.  At the
other end of the scale, the dlesel, although not excessively high in noise level,
produces a harsh unpleasant sound and was rated  'poor' at A points.

     The stratified charge engines employing direct injection (PROCO, TCCS and
MAN-FM) were all rated more or less acceptable.  Although the combustion
characteristics were considered similar to the dlesel a combination of lower
pressures and smoother cylinder pressure diagrams generally allowed £ to 1£ points
higher rating.

     Of the remaining power plants the rotary was considered good (Score 7) and
the VW engines  less than good  (6 points).
26.  Vibration and Torque Recoil  (Weighting 2.18)
     Engine

     V-8 GASOLINE
     IL-6 GASOLINE
     PROCO V-8
     PROCO IL-6
     PROCO V-8
     TCCS V-8
     TCCS IL-6 T/C
     CURT ISS-WRIGHT ROTARY
     TCCS V-8 T/C
     MAN-FM V-8
     VW V-8
     VW V-8
     CVCC V-8
     CVCC V-8
     DIESEL V-8
Emission Target

   Primary
   Primary
   Primary
   P r i ma ry
   Secondary
   P r i ma ry
   Primary
   Primary
   Secondary
   Primary
   Primary
   Secondary
   Primary
   Secondary
   Primary
Score

 8
 7-5
 6.5
 6
 6.5
 6
 5.5
 7.5
 6
 5
 8
 8
 8
 8
 6
Rating
17.
16.
14.
13.
   35
   17
   08
   17
   08
   99
   35
   08
   9
13
11
16
13
10
17
17
17
17.M
13.08
   kk
     The aspect of vibration and  torque  recoil
to the feel or refinement of a vehicle.
                is undoubtedly a major contributor
     A V-8 power plant having  similar combustion characteristics to a conventional
gasoline engine should be quiet enough as  to make  the user unaware of any
reciprocating motion.   In this respect It  was considered that the VW and CVCC
power plants were equal  to  the conventional V-8 gasoline engine and rated at 8
points being almost  the  best practical.  Only marginally Inferior (Score 7.5) were
the IL-6 gasoline and Rotary engines.

     The direct injection engines,  including the dlesel, were all rated lower,
                                                                               117

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but better than acceptable,  due to running unthrottled  and  having slightly rougher
torque characteristics.
                           ,,  ///////////A
                          f  c>  A'  V  -V  •*  <*v  c?  o,    v
-------
RESULTS

     The product of  the  rating  and  the weighting  for each performance aspect was
summed for each power  plant  and the results are shown  In the table below:-

Englne                     Final  Score         Primary  Target    Secondary Target
                        (to nearest  whole          Position            Position
                             number)

V-8 GASOLINE                  616                   2
IL-6 GASOLINE                 62?                   1
PROCO V-8                     615                   3
PROCO IL-6                    599                   5
PROCO V-8                     576                                      2
TCCS V-8                      566                   9
TCCS IL-6 T/C                 5*»7                   11
CURTISS-WRIGHT ROTARY         552                   10
TCCS V-8 T/C                  517                                      k
MAN-FM V-8                    57*»                   8
VW V-8                        586                   6
VW V-8                        561                                      3
CVCC V-8                      613                   1*
CVCC V-8                      583                                      1
DIESEL V-8                    581                   7  *

     * Not strictly  comparable  due  to different fuel.

     These results are revealing In that  they  indicate how small the relative
differences are between  the  power plants.  With the rating methodology employed a
power plant rated as acceptable in  each of the performance aspects would achieve
a score of 500 but If  a  zero were to occur In any score, that power plant must be
rejected whatever Its  final  total.   As none of the candidates rate zero  In any of
the performance aspects  and  all  achieved  a total  score in excess of 500, all must
be considered as viable  alternatives.

     The highest scoring power  plant, the conventional European type IL-6 gasoline
engine scored approximately  20% more points than  the  lowest, the TCCS secondary
emissions engine.  Of  particular Interest  is the  score attained by the PROCO primary
emissions engine which attained a similar  rating  to the conventional V-8 gasoline
engine.  With a slightly lower  total score than the PROCO V-8 engine, came the CVCC
primary engine followed  by the  PROCO IL-6.  The position of the IDI diesel in the
'table is not directly  comparable with the other power  plants since the fuel  is
different from the other power  plants, but was included In the rating, so that a
comparison could be  made with the previous diesel  survey.

     Of the candidates for the  secondary  emissions target (O.*f g/mile NO ) the
CVCC and PROCO engines were  awarded greatest merit.  However, by the definition of
this methodology, none of  the other combustion systems could be completely ruled
out.

CONCLUSIONS

     The rating methodology  evolved has allowed the different power plants to be
compared on a numerical  basis.   Its application to the fifteen candidate power
plants selected for  appraisal has resulted In them all being proved viable for the
proposed 3500 Ib vehicle to  some degree.
                                                                               119

-------
     The most suitable engines, those with the highest total score, were the con-
ventional gasoline engines and the PROCO V-8 primary emissions stratified charge
engine, which came second to the IL-6 gasoline engine.

     For the secondary emissions target the CVCC secondary engine achieved the
highest score followed by the PROCO secondary engine.
120

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                          DISCUSSIONS AND RECOMMENDATIONS

GENERAL DISCUSSION

     The unthrottled stratified charge engine has been sought throughout  this
century as the epitome for fuel economy.  The advent of exhaust emission  legis-
lation increased the fervour of the search and, indeed, Improvements In economy
with unthrottled engines have been demonstrated.  Conversely, the exhaust emission
legislation has also condemned the unthrottled stratified charge engine,  due  to  its
Inherent characteristics of emitting high HC emissions In spite of the low CO  and
NO emissions.  This survey has indicated that the hydrocarbon emissions at low
loads cannot be avoided, due to the quenching of some of the air and fuel mixture
by the cylinder walls and the low gas temperatures during combustion.  A  catalyst
is needed to remove the emissions in the exhaust system, but even here there  are
problems.  Since the exhaust temperature Is  low, the catalyst efficiency  is lower
than in a conventional gasoline engine.

     The only practical approach to reducing HC emissions from stratified charge
engines is to throttle the induced air, so that the mixture  in the cylinder has  an
air fuel ratio of around 17 to 20.  In this  region, Jn-cylinder formation of  HC
emissions is reduced to a minimum, exhaust temperatures are  relatively high,  and
there is sufficient oxygen in the exhaust gas so that further oxidation of the
HC can be completed in the exhaust system.   This approach has been followed In
Ford PROCO, Honda CVCC, VW and Porsche engines.  The only exception among the
principal stratified charge developments has been Texaco TCCS and MAN-FM, where
unthrottled operation has been maintained under most conditions.  The TCCS engines
have high HC emissions and the high degree of exhaust treatment which is  required
to meet emission targets is a direct result  of this decision.  HC emissions of the
MAN-FM are good, but this engine has not reached the stage of an automotive
application.

     The direct injection stratified charge  engines such as  PROCO, TCCS and MAN-FM
appear to have the greatest potential for low fuel consumption.  The higher gas
velocities which occur during the combustion in divided chamber engines  (CVCC, VW,
Porsche, etc.) lead to higher heat transfer  and some loss in fuel economy.  The
need to throttle most of the engines for HC  control has also involved an economy
sacrifice.  The end result is that the fuel  economy advantage of the best D.I.
engine (i.e. PROCO) over the good gasoline engines Is relatively small.  The TCCS
engines do not emerge as the best In fuel economy due to various trade-offs in
meeting the HC standard.  Exhaust gas reelrculation Is used, partially to reduce
NO and partially to increase exhaust temperatures and aid in HC control.   The
divided chamber engines have fuel economies  similar, or slightly worse than the
best conventional gasoline engines.  Category  IV engines (e.g. VW and Porsche) are
at a relatively early stage of development,  and some small  increase  in economy
may still be possible.  However, category V  engines (e.g. Honda CVCC) are unlikely
to improve on the economy of good gasolIne engines If thermal  reactors are used  to
control HC and CO.  It is important to  realise that the energy  In the fuel can only
be used once, either as output work due to better fuel economy, or else as exhaust
energy to help control HC and CO emissions,  BUT NOT BOTH.   If a stratified charge
engine emerges In the future, which can give better economy  than a good gasoline
engine, then it will almost certainly not use a thermal reactor for exhaust control,
and a catalyst is the only alternative.  This  Is disappointing, as the durability
of thermal reactors Is better than that of catalysts, and likely to  remain so.

     The question must Inevitably be raised:  Can any stratified charge engine meet
Q.k] g/mile HC without catalytic reactors, while improving on the economy of the
existing good gasoline engines?  The answer  which emerges from  this survey is :  No,
and there does not appear to be any likelihood of such an engine emerging If It  Is

                                                                                121

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based on an a spark ignition combustion process.  As compression ratio Increases,
and moves towards compression Ignition, the HC problem does reduce to some extent,
but the level of O.k\ g/mi1e HC is still unattainable.  The good results from
MAN-FM In this respect are probably related to the higher CR compared to all
the other engines surveyed.

     The nitrogen oxide emissions of stratified charge engines are universally
lower than for conventional gasoline engines.   The divided chamber engines in
categories IV and V can often achieve the primary targets (I.e.  1.5 g/mile)
without EGR.  The direct  injection engines have varied performance in this respect,
TCCS and MAN-FM having low NO , but PROCO being substantially higher.  The
particularly attractive feature of stratified  charge engines is  their ability to
meet the secondary emission target of 0.4 g/mile NO .   PROCO, TCCS and Honda  CVCC
have all demonstraJ-ed this ability In a vehicle, bu£ the quantities of EGR required
have involved considerable losses in performance and driveablIity, and in the case
of TCCS and CVCC, an additional large economy  sacrifice.  The PROCO, due to its
Inherent fast burning, has only a small loss In economy at the secondary target.
Perhaps the most significant conclusion to emerge from this survey is the practical
and theoretical advantages of Category IV engines (e.g. VW and Porsch) at low NO^
levels.  VW and Porsche have both demonstrated NO  levels below  1  gm/mile without
EGR.  The secondary targets could probably be  achieved with lower  penalties in
performance and drlveabllity than engines in other categories.  At the moment, the
greatest problem of the VW and Porsche engines is mechanical complexity, due  to
the requirement for two Injection systems, one for port injection  and the other for
pre-chamber injection.  However, this survey has revealed certain  alternatives
which, with development, might reduce the injection system cost, such as the
Schlamann rubber pump and the Bonner pump less  injector.  Meeting the secondary
emission targets will almost certainly lead to further reliance  on catalysts  to
remove HC and .CO.

     Some of the stratified charge engines reviewed bear similar characteristics
to the diesel, particularly those In categories II and III (TCCS and MAN-FM)  and
some in category IV.  The full load performance of these engines is limited by
the onset of smoke, and the difference with the diesel engine Is principally  in
the ability to operate on gasoline as a fuel.   Partlculate emissions from these
engines are higher than the conventional gasoline engines.

     Some types of stratified charge engines have high noise levels, but this
problem may occur in different regions of the  power spectrum.  If  the charge
stratification Is arranged by air motion, i.e. by directed ports such as PROCO, or
medium sized swirl  chambers, then full load noise is usually relatively high.  The
air motion causes higher  turbulence levels than in the gasoline  engine, and the
mixture burns at an excessive speed.  The TCCS and MAN-FM engines  are an exception
to this rule, as the combustion rate is controlled, either directly or Indirectly
by the rate of fuel Injection.  Engines with small pre-chambers  (around 10%)  such
as Porsche and Honda have lower full load noise levels, as the gas velocities and
turbulence at the beginning of combustion are  little greater than  In the conventional
gasoline engine.  While the unthrottled engines such as MAN-FM and TCCS have  low
noise levels at full load, Idling noise is usually higher than the gasoline engine.
This may mean that  idling noise is controlled  mainly by maximum cylinder pressure
rather than rate of pressure rise.  Typical maximum cylinder pressures would  be
20 bar for an unthrottled engine and only 7 bar for an engine throttled to an air
fuel ratio.of 15-   Noise from injection equipment may also be significant during
idling.
  122

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Alternative Engines

     Two-stroke stratified charge engines have been studied under Category VII,
and though some have made distinct improvements in emissions with respect  to
the conventional 2 stroke, they still do not equal their b stroke counterparts.
Many of these studies have centred on the piston ported engine, where the  control
of the air movement is difficult.  A more promising arrangement Is one similar  to
Heintz using unlflow 2 stroke, with a poppet valve as one port, and the piston
controlling the ports in the  liner, as the other.  Arranging charge stratification
within this type of engine Is  less difficult, although the basic problem of high
HC, associated with stratified charge engines is still not solved.  In addition,
the mechanical complexity of  the engine is Increased.  The only advantage  compared
to a A stroke engine is a reduction in overall engine size.

     The two piston Kushul engine  is an interesting development, and the reported
fuel consumption results are  exceptionally good.  This area might warrant  further
study.

     In view of the fundamental problem of HC emissions with stratified charge
engines, uncovered by this survey, some alternative to stratified charge should be
sought.  The source of the HC  formation Is linked with spark ignition of the
mixture In the cylinder.  The  flame initiated at the  plug  is easily doused by very
lean mixtures, leaving the unburnt fuels to be released as HC.  Therefore  combustion
which  Is controlled by a flame front must be avoided.  The only two recognised
methods of causing combustion  in engines are by a compression or spark ignition,
and the problem associated with compression ignition  are well known.  The  clear
indication from this survey  is that other methods of  causing combustion in engines
should be studied.  The most  obvious alternative would be  to catalyse the  air fuel
mixture.  If the mixture were  passed through a catalyst during combustion, then
HC emissions would be completely removed.  At the end of the compression stroke
the gas pressure and temperature are more favourable  for oxidation than in an
exhaust system.  Furthermore,  stratification would not be  required as a homogeneous
lean mixture of any mixture  strength could be oxidised.  The engine  load could be
simply regulated by the amount of  fuel admitted  to the engine.  A possible
arrangement for catalysed combustion is shown  in Fig. Dl.  The  induced air has an
imparted swirl of 2 times engine speed.  This swirl  level  is accelerated  into the
piston cup at tdc.  The top  of the cup is enclosed by a catalysed wire mesh with
a further surface bisecting  the cup.  At tdc, fuel is injected through a two hole
nozzle Into the swirling air below the wire mesh, and is then swept  through the
bisecting mesh and burnt.  During  the expansion  and  exhaust strokes  the burnt
mixture coming from the cup  into the remainder of the cylinder must pass through
the mesh on the top of the piston.  Therefore HC emissions are controlled.  The
mesh might also need to be pre-heated before starting the  engine.  This idea has
not received a detailed feasibility study, and  Is simply included here  in an
attempt to promote ideas for alternatives to spark ignition.

Other Results of Survey

     Some general comments can be made regarding  the  review of mathematical models
In each category.  While the number of models was large, the actual experimental
data on which the models were based was extremely limited.  The most  critical
area in this respect was heat transfer to the cylinder walls.  This has a funda-
mental effect on fuel consumption, performance and N0x emissions.  Many of the
models completely  Ignored heat transfer, while others used the empirical relations
established by Woschni, Annand and Eichelberg on diesel and gasoline engines.   It
is very doubtful if these relations can be applied,  in view of the different gas

                                                                               123

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densities, compositions, and velocities In stratified charge engines.  It Is
suggested that further combustion photography work and instantaneous heat transfer
experiments should be conducted so that reliable empirical results can be
established and so justify the complexity of the computer simulations which are
already developed.  Droplet formation and evaporation from injectors is another
area where experimental data is missing.

Discussion on Application to Motorcycles

     Existing two stroke motorcycle engines will experience great difficulty in
achieving the target emission levels.  At present many four stroke engines are also
outside the target, although this is the result of over-enrichment of the
carburettor, to give good performance and drlveabl1ity.   If a small loss In
acceleration is accepted, the carburettor mixture strength of the motorcycle
engine can'be set leaner, and the emission targets can be achieved with ease.
Ricardo tests have shown that this approach can also Increase fuel economy by up
to 50%.  Therefore, It is not practical to consider stratified charge versions of
motorcycle engines at these emission targets, since the extra mechanical complexity
is not justified.  The four stroke motorcycle engine must work through the same
evolutionary process as that of the car engine in the period of the later 1960's
and early 1970's, i.e. better manufacturing tolerances on carburettor settings and
ignition timings, resulting In engine operation at higher air/fuel ratios.
Eventually, as motorcycle emission levels become more severe, stratified charge
engines must be considered.  The only practical arrangements would be the Honda
CVCC process for cylinder sizes greater than 200 cc and the Kushul process for the
flat four arrangement (probably above 750 cc).

Results of Rating Methodology

     The stratified charge combustion systems which were considered to be viable
power plants were configured, and the various aspects of the performance were
estimated.  Finally, the engines were rated by a scoring technique based on all
aspects of the engine and vehicle performance.  The results are shown below:-
Eng i ne
GASOLINE V-8
GASOLINE IL-6
PROCO V-8
PROCO IL-6
PROCO Vz-8
TCCS V-8
TCCS IL-6
TCCS V-8
CURT ISS-WRIGHT
MAN-FM V-8
VW V-8
VW V-8
CVCC V-8
CVCC V-8
DIESEL
Primary target
Primary target
Secondary target
Primary target
Primary target
Secondary target
Primary target
Primary target
Primary target
Secondary target
Primary target
Secondary target
Primary target
                   Points
616
627
615
599
576
566
547
552
517
574
586
561
613
583
581
                    Posi tion
P r i ma ry

   2
   1
   3
   5

   9
  10

  11
   8
   6
                                                                       Secondary
2


/4



3

1
     The results from the first k engines were very close, and raised many questions,
particularly with regard to the weighting of each aspect of vehicle performance.
 124

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Any alterations of the weighting can significantly affect the overall  result.  A
number of comments are listed below.

1.   Each of the components of the  legislated exhaust emissions (i.e.  HC,  CO,  NO  )
     were marked either 5 or 6 (i.e. acceptable) as the configurated engine  was
     estimated to meet the target at low mileage.  In addition, the weighting  of
     each of the exhaust emission components was 3-99, 3-61,  3-92  respectively.
     However, the durability of the emission control  equipment and the engine  was
     only given a total weighting of ^.80.  Since the durability of catalysts  is
     the critical factor in many of the configurated engines, an increase in the
     weighting of this aspect would significantly Improve the position of the
     CVCC engines.

2.   The engines configured are at various stages of development.   The complex
     mechanical fuel  injection equipment of the VW engine might be considerably
     simplified in the future.

3.   The weighting figures generally display a concern with environmental issues
     such as exhaust  emissions and energy utilisation, with a relatively lower
     weighting on vehicle first cost.  Automotive manufacturers would probably
     consider vehicle first cost to be of critical importance.

k.   Market penetration and amortization of production plant costs have not been
     considered in the engine cost analysis.  Such an approach would probably
     give the conventional gasoline engine an advantage over alternatives.
                                                                                125

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GENERAL CONCLUSIONS

1.   This survey has  revealed a basic  limitation of unthrottled stratified charge
     engines,  in that hydrocarbon emission levels are always very high.  These
     levels can be reduced by throttling the engine, but they are usually still
     greater  than the conventional gasoline engine.  There are two primary methods
     for HC control.  Fuel economy can be sacrificed to increase the exhaust
     temperature and aid HC oxidation  In the exhaust.  Alternatively, reliance
     can be placed on catalytic reactors, although even here there will be some
     economy  penalty.

2.   A new method of engine combustion is needed, besides spark or compression
     ignition, which will be satisfactory In oxidising lean air fuel mixtures,
     and will  avoid the formation of unburnt hydrocarbons.

3-   Carbon monoxide emissions from stratified charge engines are universally low,
     although In CVS  tests they are usually above the primary target of 3.*» g/mile.

k.   NO emissions vary, depending on the stratification.

     (NO emissions at an air fuel ratio of 16)

Rating of Categories
                                                 Example
     Homogeneous charge gasoline engine                             Highest

     Category 6                                  IFF

     Category 1                                  PROCO

     Category  2 and 3                            TCCS

     Category  5                                  CVCC

     Category  k                                  VW                 Lowest
\ r
     Exhaust diluent engines may give even lower levels of NO,  but at the expense
     of economy.,

5.   The best possible fuel economy from a reciprocating I.e.  engine is attained
     by completely unthrottled operation and control  of engine power by fuel flow
     alone.  None of the engines reviewed has reached the fuel  economy levels which
     are theoretically attainable, due to high heat transfer losses caused by
     charge agitation and movement during combustion, and matching problems of air
     swirl and fuel Injection over the speed and load range.  Furthermore, the best
     economy figures attained have been further compromised by modifications of
     the engine operating parameters such as the introduction  of throttling to
     reduce HC emissions.  The fuel economy figures reviewed in this survey have
     been relatively disappointing.  Only the direct  injection engines have shown
     any improvement over baseline conventional gasoline engines.   These baseline
     engines were chosen to be representative of good current  engines, rather than
     average examples.

6.   The specific torque output (i.e.  BMEP) of a naturally aspirated stratified
     charge-engine at the primary emission target will  always  be lower than
     conventional gasoline engines, unless the stratified charge engine is fitted
     with an air pump and exhaust oxidation device.  Without exception air pumps
     are avoided on stratified charge engines, and the  minimum air fuel  ratio of

  126

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     the engines Is arranged to be leaner than stolchlometric.   The  maximum
     specific torques recorded from the naturally aspirated engine in  this survey
     was around 8.5 bar.  Many engines could not attain this figure, particularly
     those where fuel injection was occurring In the region of  50 -  0° BTDC at
     full load.  Under these conditions, the maximum specific torque of the engine
     is limited by the onset of smoke.  The actual smoke characteristics depend
     on the combustion principle.  These engines also have higher paniculate
     emissions than conventional gasoline engines.

7-   A multi-fuel capability is usually dlspJayed by stratified charge engines
     which resemble the diesel, and where the combustion is being controlled mainly
     by the rate of fuel injection.  Carburetted stratified charge engines  have  no
     multi-fuel capability In the accepted sense.

8.   The mechanical complexity and cost of a stratified charge engine  is completely
     governed by the combustion principle.   In general these engines are more
     expensive than the gasoline engine even when meeting the same emission  targets.
     The production costs of stratified charge engines may vary from a few percent
     to twice the  level of the gasoline engine.

9.   Engine size and weight Is  influenced by the combustion system.   The only
     rotary stratified charge engine  reviewed,  I.e. Curtiss-Wright,  had a
     considerable advantage in  this respect.  However, the rotary stratified
     charge engine, at  Its present stage of  development, suffers from all the  same
     problems as the rotary gasoline  engine,  i.e. poor fuel consumption and very
     high HC emissions.

10.  Full load noise Is governed by the maximum  rate of pressure  rise,  the actual
     shape of  the  pressure diagram and  the maximum  cylinder pressure.

     Generally the actual noise  level  is governed by  the category:-

Full Load Noise  Levels  in Comparison  to  the  Gasoline  Engine

               Category          Noise

                   1              Higher

                   2              Similar

                   3              Similar

                   1»              Higher  if  pre-chamber size  above 10% of clearance
                                 volume.   Otherwise similar

                   5              Similar  if  stratification maintained at full load.
                                  If mixture  enriched  combustion  becomes harsher.

                   6              Similar

                   7              Depends  on  type

11.  Noise under idling and  low load  conditions is  highest with  unthrottled engines.

12.  Startablllty  of most of  the engines  reviewed was good,  although  some of the
     engines  with  in-cylinder injection alone, required the addition of fuel into the


                                                                               127

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     main induction system  during  starting at very  low  temperatures.

13-   When the coolant  is  cold,  driveability of engines  with  in-cylinder  fuel
     Injection Is better  than with carburetted engines.

1A.   Turbocharglng Is  only  attractive  for unthrottled engines.

15-   Stratified charge versions of motorcycle, engines are  not  economically
     attractive at the motorcycle  emission target,  but  the Honda and  Kushul
     processes may be  practical for lower emission  levels.

16.   Engines from categories  1  to  5 were configured and rated  by a jury  under
     26 topic areas.   The overall  result of the  rating  was that the Ford PROCO
     and Honda CVCC engines were possible alternatives  to  the  gasoline engine at
     the primary emission target,  and  that these engines,  together with  the  VW
     engine, were viable  power  plants  at the secondary  target.  However, in
     achieving the secondary  targets there will almost  always  be severe  sacrifices
     in specific power output,  driveabllity and  fuel economy.  Only the  Ford PROCO
     system could meet the  secondary target without a significant reduction  in
     fuel economy.  The performance of the VW system at the  secondary targets  is
     not proven.
 128

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GENERAL RECOMMENDATIONS

1.   The scavenged pre-chamber engine  (e.g. Honda CVCC) should continue to
     receive study as an interim measure to achieve the primary emission target.
     Although It has demonstrated the ability to meet the secondary target,  it
     may not prove to be a satisfactory power plant in the long term,  due to poor
     fuel economy and drlveability.  This process may also be practical for
     motorcycles with cylinder sizes above 200 cc.

2.   The Ford PROCO emerged high in the rating study and although catalyst
     durabi11ty,first cost and noise problems exist, it has some attractive
     features.  Notably the secondary emission targets have been demonstrated
     with virtually no loss in fuel economy compared to existing gasoline engines.
     Therefore, continuity of production could be achieved as the emission levels
     were reduced.

3.   As the engine with the lowest exhaust emissions and best test bed fuel
     consumption of any reviewed In this survey, the MAN-FM should be applied
     to an automotive vehicle, so that a direct comparison can be made with  other
     stratified charge engines.  The multi-fuel capability of this engine may
     also prove useful in other applications.

*».   The Porsche and VW engines should receive further study as configurations
     most likely to achieve the secondary emission targets without sacrifice in
     durability or engine performance.

5.   Further investigation of the Kushul engine is recommended.

6.   Research groups should be encouraged to study alternative methods for
     Initiating combustion, besides compression and spark ignition.  The basic
     premise that unthrottled engines, operating at moderate compression ratios
     could give better utilisation of energy than existing i.e. engines, is  sound.
     The exhaust emission limitations associated with existing stratified charge
     engines is related to the method of combustion, i.e. Initiating the combustion
     with a spark and relying on flame propagation to oxidise all the fuel.

7.   In the event that alternative methods of initiating and controlling combustion
     are not successful, the problem of HC formation in spark Ignited stratified
     charge engines should receive a fundamental study.  This should include the
     source of HC emissions, and possible methods of control, both irvcyllnder
     and in the exhaust system.  It may be that the formation mechanism in single
     chamber and divided chamber engines will be different.

8.   Understanding of combustion and heat transfer in stratified charge engines is
     rather limited.  Further experimental studies by combustion photography,
     instantaneous heat transfer measurements and fuel injection droplet
     characteristics would establish empirical relations, and help in the form-
     ulation of complex mathematical models.  Existing models are of limited use,
     due to out-moded and non-appl1 cable empirical relations.
                                                                             129

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ACKNOWLEDGMENTS

     Ricardo would like to acknowledge the assistance and information given in
the preparation of this report, by the following Companies:

                                     Ford

                                     Texaco

                                     Curtlss-Wrlght

                                     MAN

                                     British  Leyland
130

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   Figure Dl.  Proposed Alternative Approach for Combustion Initiation
   in Reciprocating Internal Combustion  Engine.
CATALYSED  GRID
FORMING CAP FOR
PISTON  BOWL
1 HOLE  FUEL
  INJECTOR
                                        BISECT/NO  CATALYSED GRID
                                                                      131

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                                  TECHNICAL REPORT DATA
                           (Please read Instructions on the reverse before completing)
          -74-011-b
                             2.
                                                          3. RECIPIENT'S ACCESSIOWNO.
4. TITLE AND SUBTITLE
 A Study of Stratified Charge For Light Duty
 Power Plants     Volume 2
             5. REPORT DATE
              October  1975
             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
  Ricardo and  Co.
             8. PERFORMING ORGANIZATION REPORT NO.


              DP 20437
9.P.ERFOBMING ORGANIZAJION NAME AND ADDRESS
 Ricardo &  Co.  Engineers  (1927)  LTD.,
 Bridge Works,  Shoreham-by-Sea,  Sussex, BN4 5FG'.
 England.
                                                           10. PROGRAM ELEMENT NO.
             11. CONTRACT/GRANT NO.


              68-03-0375
 12. SPONSORING AGENCY NAME AND ADDRESS
 Environmental Protection  Agency,  Office of Air and
 Waste Management, Office  of  Mobile Source Air Pollution
 Control, Emission Control  Technology Division, Ann Arbor
 Michigan 48105
             13. TYPE OF REPORT AND PERIOD COVERED
              Final Report
             14. SPONSORING AGENCY CODE
 15. SUPPLEMENTARY NOTES
 The first part of this  report was  issued as: EPA-460/3-74-011,  dated July 1974,
 NTIS No. PB-236 896/as
 16. ABSTRACT
    The objectives of this project were to determine the acceptability of various
 types of stratified charge engines  as  potential power plants  for light duty vehicles
 and motorcycles in America.  The light duty vehicle considered was  a 4/5 seat compact
 sedan with good acceleration capabilities and exhaust emissions  below a primary target
 of 0.41  g/mile HC, 3.4 g/mile CO, 1.5  g/mile NOX.  A secondary target of 0,41 g/mile
 HC, 3.4  g/mile CO and 0.4 g/mile NOx was  also considered.

    A literature survey was undertaken,  comparing stratified charge  engines with exam-
 ples of  good conventional gasoline  and diesel engines. While  some stratified charge
 engines  had exhaust emission or fuel economy advantages, there were always sacrifices
 in  other areas.

    Eleven engines  were configured,  four of which were specifically  directed towards the
 secondary emission targets. A method of rating the engines was derived, and the design
 concepts were compared with two gasoline  engines by a jury panel. The overall result
 was that the Ford  PROCO and Honda CVCC  combustion processes were serious contenders to
 the gasoline engine at the primary  emission target, and that  both of these systems, to-
 gether with the VW combustion process,  might be suitable at the secondary targets.
 7.
                               KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS  C. COSATI Field/Group
 Exhaust Emissions
Stratified Charge  Engines
 >ower Plant Rating Methodology
 Engine Design
Literature Review
 Light  Duty Vehicles
 Light  Duty Engine
 Gasoline/Stratified
   Charge  Comparison
 Emission  Controls
 Fuel Economy
 8. DISTRIBUTION STATEMENT
Release Unlimited
                                             19. SECURITY CLASS (This Report)
                                               Unclassified
                                                                        21. NO. OF PAGES
                              143
                                             20. SECURITY CLASS (Thispage)
                                              Unclassified
                                                                        22. PRICE
EPA Form 2220-1 (9-73)

132

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