EPA-AA-TEB 70-2
Exhaust Emissions From A Turbocharged
Texaco Combustion Process (TCP)
Stratified Charge Engine
April 1970
John C. Thomson
Division of Motor Vehicle Pollution Control
National Air Pollution Control Administration
Department of Health, Education, and Welfare
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Subject: TCP Jeep test program results
Texaco, Inc., through a U. S. Army contract has built an
updated version of their stratified charge engine. Because
preliminary Texaco data showed a significant reduction in
emissions from previous NAPCA results,1 an emission test
program was conducted on the new engine.
The engine was installed in the same M-151-1/4 ton army
jeep used in the previous test. Tests were conducted on
the chassis dynamometer using both continuous analysis
and the constant volume sampling system. Two fuels, and
a mixture of the fuels, were used and both hot and cold
starts were monitored.
A standard L-141 engine (four cylinder 3-7/8" bore, 3"
stroke - 141.5 CID) was modified by Texaco to incorporate
the required features for operation on their stratified
charge, multifuel, turbocharged, combustion process. This
system utilizes high pressure cylinder injection of the
fuel into a controlled- iale:L- air sw.irLpat.tje.nL in., con-
junction with spark iga^ti-oa^ Msk, •fc&fco.ttklB.g-. «xL .tke..... iale-t.
air is required and load control is accomplished by control
of the injected fuel quantity only,. Turbocharging and
a special ignition system were added in their latest design
to improve combustion and reduce smoke;fuel to 115/145
aviation gasoline may be used. For these series of tests
CITE fuel (MIL-F-45121B) and Indolene 30 (see Appendix) were
used along with a mixture of 50% gasoline and 50% CITE.
The following tests were conducted:
a) 1968 Federal Procedure (modified) for exhaust
emissions using Indolene 30 and a separate test using
50% CITE, 5.0% gasoline.
b) 9 cycles of the 7-mode Federal cycle used with
constant volume sampling (CVS) on both Indolene 30 and
the CITE-gasoline mixture.
1 See Exhaust Emissions From Texaco Combustion Process
(TCP) Stratified Charge Engine. National Air Pollution
Control Administration, Ypsilanti, Michigan August 1968.
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c) Selected hot cycles using both Indolene 30 and
straight CITE.
The Federal Procedure data were obtained with NDIR instru-
ments while both NDIR and FID were used in the CVS tech-
nique. The Saltzman method and the Whittaker "NOX Box"
were used for determination of oxides of nitrogen in the
CVS sample.
Dynamometer Results
Mass emission results for the Turbocharged TCP jeep along
with previous data on a standard jeep are shown in Figure
1. Both tests are 9 cycle repeats of the Federal cycle.
The results of the dynamometer evaluation based on mass
emissions clearly show that the turbocharged TCP jeep
engine greatly reduces all of the measured exhaust com-
ponents.
The effects of dilution with an unthrottled air engine,
as in the TCP jeep, leads to extremely high air-fuel ratios.
Due to the low concentrations of CO and CC>2 caused by non-
homogeneous combustion of a stochiometric mixture surrounded
by large quantities of air, the use of the conventional cor-
rection factor used in the Federal test procedure appears
to bias exhaust gas hydrocarbon results.2 Because of this,
the correction factor was not applied to the data and the
concentration values shown in Figure 2 were calculated
using revised weighting factors. The new weighting factors
were calculated by the procedure originally used by the
State of California but based on air flow data from the
previous TCP engine. The additional quantity of air flow
caused by the turbocharger is not significant in the portions
of the cycle measured*
The original mode breakdown and percent of total volume in
each mode is the product of the percent time in mode and
the average engine air flow in each mode. The final
weighting factors were obtained by combining the percent
See M.. W. Jackson, ET. AC, The Influence of Air-Fuel
Ratio, Spark Timing, and Combustion Chamber Deposits
on Exhaust Hydrocarbon Emission. SAE 486A, March 1962,
Appendix D.
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of total volumes in each mode in the manner used by the
State of California in the design of the original seven-
mode cycle. (For further details see "The California
Motor Vehicle Emissions Standards" by G. C. Hass?S:AE
paper number 210A August 1960). The weighting factors
used for the TCP engine are:
Idle .094
0-25mph .139
30 .099
30-15 .197
15 .081
15-30 .292
50-20 .098
Figure 2 compares results taken in previous tests with the
naturally aspirated TCP jeep and those taken with the Turbo-
charged jeep. This shows an approximate 501 reduction in
Hydrocarbons with a 2.51 reduction in carbon monoxide.
Figure 3 reports the results of hot start cycles run to
provide confirmation of repeatability.
In all tests but one a manual dump valve was used to prevent
pump leakage during the 50-30 mile per hour decel. A re-
vised pump with improved features is now under investigation
by Texaco, Inc. the solution of the pump leakage problem
would prevent potential engine run away at light load and
ensure full cut off on deceleration.-, The only major engine
problem during the program was a broken oil pump and the
repair should not influence the emission test results.
'Smoke
Due to the Diesel type combustion there is some production
of soot and smoke. To protect the instrumentation, a pre-
filter was placed in the continuous sample line. At the
conclusion of testing, no evidence of hangup in the sample
lines or the CVS unit was found. Attempts to measure smoke
and odor on this vehicle will be made in the near future.
Summary of Results
a) The addition of the turbocharger and an improved ignition
system have shown significant improvements over the standard
vehicle and the previous TCP engine.
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b) Mass emissions show large improvements over the standard
vehicle with a 10 fold reduction in CO, a 4 fold reduction
in NOV and a reduction of 1/2 in HC.
.A. . .
c) A small fuel effect on emissions was detected although
this may be due to instrument response.
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FIGURE ..1
Mass Emission Results (CVS)
Indolene 30 fuel
HC gm/mile
CO gm/mile
CO2 gm/mile
NO gm/mile
Turbocharged
TCP
3.07
10.30
361.68
1.07
Standard
M-151
8.0
100.9
4.0
HC gm/mile
CO gm/mile
CO2 gm/mile
NOX gm/mile
50% CITE / 50% Gasoline
- Tuxhach a r g.ed~
TCP
2.90
11.39
332
1.51
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FIGURE 2
Concentrations - Dynamometer
1968 Federal Procedure
Cycles 1-4
Hydrocarbon
Carbon Monoxide
Cycles 6-7
Hydrocarbon
Carbon Monoxide
Naturally
Aspirated
TCP
Indolene
222ppm
.18%
175ppm
.17%
Turbocharged
TCP
Indolene
llSppm
.15%
97.9ppm
.12%
Turbocharged
TCP
Gas/CITE
50/50
120ppm
.20%
94ppm
.13%
Weighted Average
Hydrocarbon
Carbon Monoxide
192ppm
.17%
104ppm
.13%
103ppm
.15%
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FIGURE 3
Constant Volume Sampling Results
. . • ;-Type of
'"• Test
Hot .Start
Fed Geft
No decel dump
Hot Start
Fed Cert
Manual decel dump
Cold Start
Fed Cert
and CVS
Hot Start
CVS
Cold Start
Fed Cert
and 'CVS
Hot Start
Fed Cert
and CVS
Hot \Start
Fed Cert
and CVS
Fuel
Used
Ihdolene
Indolene
Indolene
Indolene
501 CITE
50% Gas
Indolene
CITE
Subtractive
HC CO C07 NOx Hydrocarbon
FID NDIR NDIR % of total
gpm gpm SPm gpra P+B 0 A*
3.07 10.3 362 1.07 40 29
2.34 9.4 v:- .98 33 29
2.90 11.39 332 1.51 38 27
2.91 9.19 336 1.86 40 23
2.33 10.33 321 1.80 41 35
-;-r
--
30
38
35
37
24
*P+B = Parafine plus Benzene
.' 0 = Olefins
A = Aromatics
1968 Federal
Procedure Results
HC CO
NDIR NDIR
ppm %
Cas C6)
106
111
104
103
119
81
.17
.18
.13
.15
.15
.22
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APPENDIX
Fuel Inspection Data
CITE Fuel
Referee Grade
MIL-F-4512IB Iridolene
Gravity,0 API•at 60 F 48;3
Gravity, Specific at 60 F 0.7870
Viscosity, cs at - 30 F 4.12 •.-
100 F } 1.0.0 ----
Distillation, ASTM, F
IBP 152 75- -'95
10% 244 120-135
501 362 200-230
90% 458 300-325
EP 478 415
RVP 1.7 8.7-9.2
FIA - Aromatics, % 19.2 35
Olefins, % 2.1 10
Saturates, % 78.7 55
Octane Number (RON) 100
TEL Content, ml/gal 3.1-3.3
Cetane No. 38.0 -----
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