75-10 AW
Emissions from a Mercedes-Benz Diesel
Car Equipped with a Turbocharger
October 1974
Technology Assessment and Evaluation Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Environmental Protection Agency
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Background
The Environmental Protection Agency receives information about
many systems which appear to offer potential for emission reduction or
fuel economy improvement compared to conventional engines and vehicles.
EPA's Emission Control Technology Division is interested in evaluating
all such systems, because of the obvious benefits to the Nation from
the identification.of systems that can reduce emissions, improve
economy, or both. EPA invites developers of such systems to provide
to the EPA complete technical data on the systems principle of opera-
tion, together with available test data on the system. In those
cases in which review by EPA technical staff suggests that the data
available show promise, attempts are made to schedule tests at the
EPA Emissions Laboratory at Ann Arbor, Michigan. The results of all
such test projects are set forth in a series of Technology Assessment
and Evaluation Reports, of which this report is one.
The conclusions drawn from the EPA evaluation tests are necessarily
of limited applicability. A complete evaluation of the effectiveness
of an emission control system in achieving performance improvements
on the many different types of vehicles that are in actual use requires
a much larger sample of test vehicles than is economically feasible
in the evaluation test projects conducted by EPA. For promising systems
it is necessary that more extensive test programs be carried out.
The conclusions from the EPA evaluation tests can be considered
to be quantitatively valid only for the specific test car used, however,
it is reasonable to extrapolate the results from the EPA test to other
types of vehicles in a directional or qualitative manner, i.e., to
suggest that similar results are likely to be achieved on other types
of vehicles,,
Test Vehicle Description
A West Coast company, Turbocharger, Inc., is marketing a turbo-
charging kit for 1970-1973 Mercedes 220Ds'. Since little emissions
data are available for turbocharged light-duty Diesel engines, arrange-
ments were made for*EPA testing of a 1971 Mercedes 220D before and
after installation of the turbocharger kit.
The turbocharger supplied with the kit, model # 377B40 modified, is
manufactured by Rayjay. It has a 3" tip to tip diameter turbine wheel
and rated speed capability is 70,000 rpm peak (safety tested for 130,000
rpm). The basic package contains the turbocharger and plumbing necessary
for the installation. Many of the stock parts which must be removed to
make room for the turbocharger are modified for use with the kit.
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In the present design of the kit, the governor modifications
suggested result in elimination of the fuel cutoff at high engine
speed, so there is nothing to prevent the engine from exceeding its
maximum rated speed. When driving the vehicle, the engine is easy
to overspeed when accelerating hard in first and second gear. A
means of controlling maximum engine speed is to be introduced in
future kits.
The kit is designed to supply up to 10 psi boost, the specific
kit tested would actually supply 13 psi boost.
A more detailed description of the test vehicle appears on the
following page,
Test Program
The vehicle was tested in accordance with the 1975 Federal Test
Procedure (Federal Register, August 7, 1973, vol. 38 No. 151, Part III).
Testing also included the Federal Highway Driving Cycle and measure-
ment of acceleration times. All tests were run before and after
installation of the turbocharger„ Hydrocarbon emissions were measured
with a Beckman model 402 heated flame ionizatidn detector in accordance
with established EPA procedures for Diesel exhaust. The same test
fuel was used for all tests and meets EPA specifications for Diesel
fuel (Federal Register, August 7, 1973).
Test Results
1975 FTP results are given in Tables I and II. Emissions over
the 1975 FTP are broken down into individual bag data in Table III.
The effect of the turbocharger kit on emissions was negligible.
Hydrocarbon emissions increased by 13%, but carbon monoxide and oxide
of nitrogen emissions were unchanged. Fuel economy over the 1975
FTP and Highway Driving Cycle was also unchanged.
The acceleration of the vehicle improved considerably after
installation of the turbocharger. Acceleration time from 0 to 60
mph was reduced from 29.8 seconds to 21.9 seconds.
Driveability of the vehicle was very good, with no perceptible
lag on acceleration. A manifold pressure gauge installed on the
vehicle indicated rapid increases during transient, part load to full
load, operation. The turbocharger did not cause any noticeable increase
in the noise level of the vehicle, either inside or outside. No visible
smoke was observed during the acceleration tests.
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TEST VEHICLE DESCRIPTION
Chassis model year/make - 1971 Mercedes-Benz 220D
Emission control system - None
Engine
type 4-cylinder in-line,oh v, 4-cycle Diesel
bore x stroke . . . 3.43 in. x 3.64 in. (87.1mm x 92.5mm)
displacement ' "134 CID (2200 cc)
compression.ratio 21.0:1
maximum power
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Conclusions
1) The turbocharger kit improved the performance of the test
vehicle without significantly affecting either emissions or fuel
economy. This conclusion is valid only for the change in fuel injection
characteristics that were associated with this particular test car.
Attempts t.o fully utilize the excess air capacity provided by the turbo-
charger could result in transient smoke problems and/or emission
increases.
2) The turbocharger kit did not increase the mechanical noise
from the engine. Very little insulation was used with the kit,
so the lack of noise is inherent in the use of this model turbo-
charger with the 220D engine.
3) The effect of the turbocharger on engine durability has not
been established at this time.
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TABLE I
% change
from baseline
Mercedes 220D
Mass Emissions in
Grams per Mile
1975 Federal Test Procedure
Baseline
Test #
16-5953
15-5979
Average
Turbocharged
16-6124
15-6139
Average
HC
0.82
0.92
0.87
1.0
0.96
0.98
CO
2.47
2.85
2.66
2.66
2.67
2.67
C02
394.
418.
406.
400.
420.
410.
Weighted Fuel Econoii
NOx miles per gallon
1.61 25.4
24.0
1.61 24.7
1.69 25.0
1.62 23.9
1.66 24.5
+13%
0
+1%
+3%
Baseline
Test //
16-5953
Highway Driving Cycle Emissions and Fuel Economy
C02
HC
0.68
CO
2.45
295.
NOx
H.60
Turbocharged
16-6124
15-6139
Average
0.79
0.79
2.37 306.
2.25 295.
2.31 301.
-1%
MPG
33.8
1.62 32.7
1.56 33.9
1.59 33.3
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TABLE II
Mercedes 220D
Mass Emissions in
Grams per Kilometre
1975 Federal Test Procedure
Baseline
Test //•
16-5953
15-5979
Average
Turbocharged
16-6124
15-6139
Average
HC
0.51
0.57
0.54
0.62
0.60
0.61
CO
1.52
1.77
1.65
1.65
1.66
1.66
C02
245.
260.
253.
249.
261.
255.
NOx
1.0
1.0
1.05
1.01
1.03
Fuel Weighted Consun
litres/100 km
9.2
9.8
9.5
9.4
9.8
9.6
% change
from baseline
+13%
+1%
+3%
+1%
Highway Driving Cycle Emissions and Fuel Consumption
Baseline
Test #
16-5953
HC
0.42
CO
1.52
C02
184.
NOx
0.99
litres/100 km
7.0
Turbocharged
16-6124 0.49
15-6139
Average 0.49
1.47
1.40
1.44
190.
183.
187.
1.01
0.97
0.99
7.2
6.9
7.1
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Test- #
16-5953
15-5979
Average
16-6124
15-6139
Average
TABLE ITT
Bag 1
Cold Transient
HC
CO
COo
NOx
MPG
Mass Emissions in Grams per Mile
Bag 2
Stabilized
HC
CO
C09
NOx
MPG
Bag 3
Hot Transient
HC
CO
CO? 1 NOx
MPG
0.75
1.09
0.92
2.46
3.49
2.98
415.
474.
445.
1.69
__
1.69
24.2
21.1
• 22.7
0.86
0.90
0.88
2.52
.2.77
2.65
398.
416.
407.
1.59
__
1.59
25.2
.24.1
24.7
0.80
0.84
0.82
2.37
2.51
2.44
371.
379.
375.
1.59
_— .
1.59
27.0
26.4
26.7
0.98
0.97
0.98
2.91
2.66
2.79
438.
434.
436.
1.82
1.68
1.75
22.9
23.1
23.0
1.04
1.03
1.04
2.76
2.84
2.80
406.
434.
420.
1.64
1.62
1.63
24.7
23.1
23.9
0.95
0.83
0.89
2.30
2.37
2.34
360.
381.
371.
1.67
1.'59
1.63
27.8
26.3
27.1
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