73-19 AW
Exhaust Emissions from Three
Diesel-Powered Passenger Cars
March 1973
Emission Control Technology Division
Office of Air and Water Programs
Environmental Protection Agency
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Background
The Emission Control Technology Division is currently conducting
a technical feasibility study and evaluation of the light duty
Diesel engine to determine it's potential for low exhaust
emissions in light duty passenger vehicle applications. As
part of the experimental phase of this study we have tested
three passenger cars powered by Diesel engines that are in
current production. These are the Mercedes 220D, the Opel
Rekord 2100 D, and the Peugeot 504 Diesel. The Mercedes was
supplied by Mercedes-Benz of North America, the Opel by General
Motors Corp., and the Peugeot by Peugeot, Inc. Of the three
vehicles the Mercedes 220 Diesel is the only one available for
purchase in the United States.
Vehicle Descriptions
The Mercedes is a four-door sedan with a capacity of five persons.
It is powered by a four-cylinder, four-stroke, 2.2 litre (134 CID)
Diesel engine which develops 65 hp (SAE). The car is equipped
with a four-speed automatic transmission. Inertia weight is
set at 3500 pounds.
The Opel is a four-door sedan with a capacity of five persons.
The engine is a four-cylinder, four-stroke, 2.1 litre (126 CID)
Diesel engine which develops 68 hp (SAE). Inertia weight is
set at 3000 pounds. The transmission is a three-speed automatic.
The Peugeot is also a four-door sedan with a capacity of five
persons. The engine is a four-cylinder, four-stroke, 2.1 litre
(129 CID) Diesel which develops 65 hp (DIN). The transmission
is a four-speed manual. Inertia weight is set at 3000 pounds.
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Test Procedure
Tests were run on all cars as specified in the 1975 Federal
Test Procedure for light duty Diesel passenger vehicles. In
addition, several tests were run on the Mercedes after a modified
injection system was installed. The modified system consisted
of new fuel lines which incorporated dampers for the purpose of
damping out stray pressure pulses in the delivery lines to the
nozzles.
Standard instrumentation specified in the Federal Register for
measurement of CO, C02, HC and NOx was used. For the Mercedes
with the standard injection system, an IPM RS-5 flame ionization
detector (FID) was used to continuously analyze the dilute exhaust
for hydrocarbons. A Beckman 402 FID was used for the remainder
of the tests. FID oven and sample line temperature was 375°F.
Results
Emissions from the Mercedes were consistently within the 1975
limits (see Table I). The modifications to the injection system
caused no change in NOx, but resulted in approximately 25%
reductions in CO and HC (see Table II). NOx levels were about
four times the permissable level for 1976.
The Opel ran at or below the 1975 levels. CO and NOx are about
half the specified limits (Table III). HC ran very close to
the 1975 standard, with some tests above it and some tests below.
NOx is about three times the level required for 1976.
Emissions from the Peugeot exceeded the 1975 standards for CO
and HC (see Table IV). HC levels were about seven times the
allowable level and CO was slightly above the allowable level.
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NOx levels are about one-third the 1975 level.
Conclusions
Both the Mercedes and the Opel are capable of meeting the 1975
standards. The Opel has adequate power for city and country
driving. It can keep pace with traffic without using full
throttle. The Mercedes is considerably slower than the Opel
and it is necessary to use full throttle most of the time in
order to keep up with traffic. The Peugeot in its present
form does not meet the 1975 standards. This may be due to what
Peugeot calls its "deferred injection" system, which alters
the injection rate at idling speed to reduce the amount of engine
noise. The driveability of the Peugeot is comparable to the Opel,
Fuel economy was calculated from emissions data, by the 1975
FTP and the 1972 FTP. All three cars exhibit superior fuel
economy for their weight classes. Using the data from Tables
I-IV, we find the 3500 Ib. Mercedes achieved an average of
23.6 mpg in stock form and 24.6 mpg with the modified injection
system, both calculated from 1975 FTP emissions data. The
3000 Ib. Opel averaged 23.8 mpg and the 3000 Ib. Peugeot
averaged 25.2 mpg, again from 1975 FTP emissions data.
An EPA report released in November 1972 and titled 'Fuel Economy
and Emission Control" gives the following data for gasoline-
powered cars (1972 FTP):
1973 Model Year Average Range
Inertia Weight MPG
3000 16.2 12.6 to 19.7
3500 14.0 9.8 to 17.8
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The Diesel-powered cars show about 70% greater fuel economy,
by the same test procedure (1972 FTP), than comparable gasoline
cars.
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Table I
Mercedes-Benz 220 Diesel
Gaseous Emissions
1975 Federal Test Procedure
(grams per mile)
Cold Bag Hot FID
Test No. HC
1 0.16
2 0.19
3 0.18
4 0.16
5 0.16
AVERAGE 0.17
1975 Standards
1976 Standards
Fuel Economy (miles
Test No.
1
2
3
4
5
AVERAGE
HC CO
0.27 1.21
1.58
0.30 1.51
0.40 1.34
0.37 1.46
0.34 1.42
0.41 3.4'
0.41 3.4
per gallon)
MPG ('75 FTP)
23.7
22.6
23.8
24.0
24.0
2316
CO 2
423.39
434.97
416.80
409.82
411.76
419.35
MPG
23.3
22.3
23.3
23.9
23.5
23.3
NOx
1.62
1.55
1.17
1.45
1.38
1.43
3.1
0.4
('72
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Table II
Mercedes-Benz 220 Diesel
Modified Injection System
Gaseous Emissions
1975 Federal Test Procedure
(grams per mile)
Cold Bag Hot FID
Test No. HC
1 0.13
2 0.13
3 0.12
4 0.12
5 0.14
AVERAGE 0.13
1975 Standards
1976 Standards
Fuel Economy (miles per
Test No.
1
2
3
4
5
HC
0.26
0.26
0.24
0.27
0.35
0.28
0.41
0.41
gallon)
MPG ('75
23.8
24.4
25.3
24.9
24.5
CO
1.15
1.01
1.06
1.05
1.13
1.08
3.4
3.4
FTP)
co2
418.66
412.35
400.12
402.38
410.03
408.71
"" ~ ~.
MPG
22.8
23.8
24.0
24.0
23.6
NOx
1.46
1.50
1.42
1.46
1.55
1.48
3.1
0.4
('72 !
AVERAGE 24.6 23.6
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Table III
Opel Rekord 2100 Diesel
Gaseous Emissions
1975 Federal lest Procedure
(grams per mile)
Cold Bag Hot FID
Test No. HC
1 0.13
2 0.16
3 0.17
4 0.17
AVERAGE 0.16
1975 Standards
1976 Standards
Fuel Economy (miles
Test No.
1
2
3
4
AVERAGE
HC CO
- 0.28 1.12
0.32 1.12
0.50 1.24
0.48 1.17
0.40 1.16
0.41 3.4
0.41 3.4
per gallon)
MPG ('75 FTP)
23.9
24.3
23.2
23.7
23.8
C0.2
414.39
409.23
427.13
419.98
417.68
MPG ('
23.3
23.5
22.7
23.1
23.2
NOx
1.37
1.29
1.38
1.32
1.34
3.1
0.4
72 FTP
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Table IV
Peugeot 504 Diesel
Gaseous Emissions
1975 Federal Test Procedure
Cgrams per mile)
Cold Bag Hot FID
Test No. HC
1 0.96
2 0.83
3 1.05
1
4 1.03
5 1.30
0
AVERAGE 1.03
1975 Standards
1976 Standards
Fuel Economy (miles per
Test No.
1
2
3
4
5
AVERAGE
HC
2.76
3.41
2.72
3:53
3.11
0.41
0.4.1
gallon)
MPG ('75
25.4
25.2
24.1
25.2
26.2
25.2
CO
3.37
3.04
3.54
3.30
3.84
3.42
3.4
3.4
FTP)
co2
399.33
394.06
407.28
397.22
379.47
395.47
MPG ('
24.3
24.3
23.3
24.2
25.1
24.2
NOx
1.05
1.08
1.09
1.07
1.04
1.07
3.1
0.4
72 FTP
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