71-3
Exhaust Emissions from a Passenger Car Equipped
with a DuPont Exhaust Emission Control System
Using 1975 Test Procedure
August 1970
John C. Thomson
Division of Motor Vehicle Research and Development
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 \v?ere measured
to provide a comparison with other low emission vehicles
having the potential for meeting proposed 1975 Federal
standards. This was a repeat test with special emphasis
on procedures to be used for 1975 vehicle testing.
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. This was the same vehicle
tested in May 1970 with minor adjustments in carburetor and
assembly of the reactor.
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 as specified for 1972
and later testing.
4. An experimental particulate test using the hot
start LA4-S3 procedure.
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. Particulates were measured using
a multiplate condenser followed by high efficiency filters.
Emission Results
The data shown in Table I compare tests run on the DuPont
automobile in April and July 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 throughout the entire test. The DuPont vehicle still
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shows excellent control over hydrocarbons and oxides of nitrogen
but only minimal control over carbon monoxide. Table 2
summarizes the tests run and results obtained in the latest
series.
No attempt was made to evaluate driveability or fuel economy.
The vehicle was turned over to DuPont at the conclusion of
testing. Some problems were found in May 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 as shown by the
June results on the corrected vehicle. Some problems in
the carburetor were also corrected prior to the tests.
Particulate emissions using a technique described in Volume
27, Jan-Feb 1966, American Industrial Hygiene Association
Journal, P. 47 were measured. As no definition of.particu-
lates has been adopted to conform to the standards for 1975
the data presented in Table 2 should not be interpreted as
being either above or below the proposed particulate stan-
dard.
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.
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Table 1
Cold 9 cycle CVS Data
DuPont Reactor
1970 Chevy 350
HC
CO
NOX*
May
0.
24.
1.
1970
70
34
29
June
0.
17.
0.
1970
49
14
95
Average of 6 Best
1970 Chevy 350 of 6
3.
37.
3.
07
35
24
2.
22.
2.
23
35
29
*NUx data from Whittaker "NOX Box", an electro-chemical
oxides of nitrogen analyzer.
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Table 2
Results of Tests*
June 30, 1970 LA4-S3 CVS
Cold LA4-S3
HC = 0.79 gm/mi
CO = 25.92 gm/mi
NOX = 1.03 gm/mi
June 30, 1970 LA4-S3 CVS
Cold LA4-S3
HC = 0.44 gm/mi
CO = 20.82 gm/mi
NOX = 0.99 gm/mi
July 1, 1970 Federal Test and 9 CVS
Cold 1970 Federal Procedure
HC = 0.24 gm/mi
CO =11.3 gm/mi
NOx = 0.44 gm/mi
Cold 9 CVS
HC = 0.49 gm/mi
CO = 17.14 gm/mi
NOX = 0.95 gin/mi
July 2, 1970 Hot Start LA4-S5 Particulate
Particulates = .44 gm/mi
*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.
LA4-S3 CVS is the proposed 1972 Federal Test procedure
using a cold start.
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