EPA-M-TEB 70-4
Exhaust Emissions from a Passenger Car Equipped
with a DuPont Exhaust Emission Control System
May 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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Vehicles Tested
The exhaust emission characteristics of a vehicle equipped
with a DuPont exhaust emission control system were measured
to provide a comparison with other low emission vehicles
having the potential for meeting proposed 1975 Federal
standards.
To obtain emission data, DuPont delivered for test a 1970
Chevrolet equipped with their latest reactor system. This
was a typical vehicle with the following modifications:
exhaust manifold reactor, exhaust gas recirculation, manifold
air injection, particulate traps with special exhaust sys-
tems, and carburetor modifications. The vehicle used a 350
cubic inch engine with automatic transmission. All tests
were run using Indolene 30 fuel.
Tests Used
The following tests were conducted:
1. Standard 1970 Federal test procedure for exhaust
emissions.
2. A closed, constant volume sampling technique using
9 repeats of the Federal emissions test cycle (CVS).
3. A closed, constant volume sampling technique using
the new LA4-S3 driving schedule.
Emission values were obtained both on a concentration basis
and on a mass basis.
Closed cycle data were taken using a constant volume sampling
technique. Bag samples were analyzed using non-dispersive
infrared^.analyzers for carbon monoxide and carbon dioxide
with hydrocarbons measured using a flame ionization detector.
The modified Saltzman wet chemical method was used to deter-
mine oxides of nitrogen.
Emission Results
The data shown in Table 1 compare one test run on the DuPont
automobile with the average of six similar 1970 passenger
cars tested and with the best of the six. This testing method
utilizes a continuous sample of the exhaust products through-
out the entire test. The DuPont vehicle shows excellent
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control over hydrocarbons and oxides of nitrogen but only
minimal control over carbon monoxide.
In Table 2, the results of all tests are reported. The
tests run on April 23, 1970, showed an increase in both
hydrocarbon and carbon monoxide emissions and a control
system failure of some type was suspected. On examination
of the engine a burned spark plug lead wire was found and
replaced. The hot cycle data on April 24, 1970, indicated
that the problem had been corrected. As the wire was re-
placed prior to the LA4-S3 test, these data are assumed
to be representative.
No attempt was made to evaluate driveabillty or fuel, economy.
The vehicle was turned over to DuPont at the conclusion of
testing on April 24, 1970. Some problems were found by
DuPont in the bypass system that allowed some exhaust to
circumvent the reactor; the effect of this problem on
emissions is not known but it is suspected to be minimal.
Additional testing of this vehicle in the future is planned,
and some type of driving evaluation is proposed.
Conclusions .
1. The DuPont exhaust emission control system greatly
reduces unburned hydrocarbons.
2. The DuPont system reduces oxides of nitrogen.
3. Very little effect is shown on carbon monoxide compared
with standard production vehicles.
4. Additional testing and evaluation of idriveability and_
economy would be beneficial.
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Table 1
Cold 9 cycle CVS Data
DuPont Reactor Average of 6 Best
1970 Chevy 350 1970 Chevy 350 of 6
HC 0.70 3.07 2; 23
CO 24.34 37.35 22.35
NO* 1.29 3.24 2.29
*NOX data from Whittaker "NOX Box" , an electro-
chemical oxides of nitrogen analyzer.
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Table 2
Results of Tests*
April 22, 1970 Federal Test and 9 CVS
Cold 1970 Federal Procedure
HC = 0.20 gm/mi
CO = 11.72 gm/mi
Cold 9 CVS
HC = 0.70 gm/mi
CO = 24.34 gm/mi
NOX = 1.23 gm/mi
NO = 0.80 gm/mi
April 23, 1970 Federal Test and 9 CVS
Cold 1970 Federal Procedure
HC = 0.5 gm/mi
CO = 13.46 gm/mi
Cold 9 CVS
HC = 1.40 gm/mi
CO = 26.58 gm/mi
NOX = 1.45 gm/mi
NO = 0.94 gm/mi
April 24, 1970 LA4-S3 and Hot Cycles
Cold LA4-S3
HC = 0.17 gm/mi
CO =27.17 gm/mi
NOX = 1.06 gm/mi
NO = 0.69 gm/mi
Hot 1970 Federal Procedure
HC = 16 ppm
CO = 0.2 %
*Federal Test is the 1970 Federal Emissions test
procedure from a cold start.
9-CVS is a closed cycle using 9 repeats of the
Federal emission test cycle with constant volume
sampling and cold start.
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