73-8
An Evaluation of a 1975
Prototype Chrysler Passenger Car
October 1972
Thomas C. Austin
Test and Evaluation Branch
Division of Emission Control Technology
Environmental Protection Agency •
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Background
One of the most promising 1975 prototype vehicles reported
to EPA during the Suspension Hearings of April 1972, was a
Chrysler Corporation passenger car equipped with twin
Engelhard catalytic converters. Based on the emission
data from this vehicle, Chrysler was predicted to be able
to comply with the 1975 Federal Emission Standards. After
the completion of the 50,000 mile durability testing,
Chrysler representatives agreed to loan this vehicle,
designated car 333, to EPA for an evaluation in our Ann Arbor
laboratory.
Vehicle Tested
Car 333 is an extensively modified-1971 Plymouth Fury equipped
with a 360 CID V-8 engine and an automatic transmission. The
heart of the emission control system used on the vehicle is a
pair of Engelhard catalytic converters. These monolithic
platinum converters were installed in each side of the exhaust
system about as far back as the front seat. Additional
modifications included exhaust gas recirculation (EGR) and
air injection.
At the beginning of our series of tests on the vehicle the
odometer registered 58,500 miles. One of the two catalysts
had been on the vehicle since the beginning of mileage
accumulation. The other catalyst-was a replacement for
one of the vehicle's original converters which had been
r-emoved for laboratory analysis. The replacement catalyst
was another Engelhard unit with several thousand miles
accumulated on it at the time of EPA testing.
Test Program
A series of tests were run on car 333 to determine what the
emission levels from such a system would be in a variety of
different vehicles. Chassis dynamometer loadings were varied
to simulate passenger car weights, with two passengers, of
3000, 4500 and 5500 pounds. Replicate tests at each of these
in'ertia weights were run. At 4500 pounds two different
configurations were tested. First the vehicle was run without
any adjustments and then it was run with the dashboard EGR switch
in the "off" position.
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Using a special "medium duty" dynamometer the vehicle was
evaluated at elevated horsepower and inertia weight settings.
During a recent procedures development program the horsepower
requirements of medium duty (6000 GVW to 14,000 GVW) vehicles
were determined. At 6000 pounds test weight 'the dynamometer
was set at 31.5 horsepower at 50 mph. 6000 pound test weight
passenger cars are tested with only 14.4 hp at 50 mph. The
increase in road load horsepower in the medium duty testing
reflects the increase in frontal area of lightly loaded truck-
type vehicles compared to passenger cars of equivalent weights.
At 7000 pounds test weight the 50 mph horsepower was set at 41.9,
Fuel consumption over the Federal urban driving cycle was
determined during each, test using both carbon balance and
weighing techniques.
The 1975 Federal Test Procedure was used throughout the testing.
A description of the Federal procedure is attached as Appendix
I.
In addition to the chassis dynamometer testing, an "over the
road" comparison between car #333 and,a 1972 Plymouth Fury
rental car was made.
Test Results
A summary of the test results appears in Tables I, II, and III.
Table I consists of data accumulated when the vehicle was tested
as if it was a passenger car of three different weights. Besides
the standard test weight of 4500 pounds, the vehicle was tested
at 3000 pounds and 5500 pounds. As shown graphically in Figure I,
there was a pronounced effect on NOx emissions when different
vehicle weights were simulated. An 86% increase in NOx emissions.
occured when the test weight was changed from 3000 pounds to 5500
pounds. Hydrocarbon and carbon monoxide emissions also tended to
increase as test weight increased but the trend was less pronounced.
The 4500 pound tests were the first run by EPA on this vehicle.
Prior to EPA testing the car operated on unleaded fuels other than
"indolene clear" test fuel for over 2000 miles. With the first
EPA test (number 12-2356) a step change in fuel type was made.
It is possible that this step change in fuel type caused the lack
of stability during these first tests.
Also presented in Table I are data accumulated at 4500 pounds with
the vehicle's dashboard EGR switch in the "off" position. It is not
known if this switch completely eliminated EGR or only reduced the
EGR rate. Shutting off this EGR switch caused a significant increase
in NOx emissions and significant decreased in HC and CO emission.
The effect on fuel consumption was insignificant.
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Since it is possible to determine emissions and carbon balance
fuel consumption values for a 1972 Federal Test Procedure (FTP)
from analysis of the first two bags of a 1975 FTP, a comparison of
fuel consumption data from car #333 with data from 1973 model year
certification vehicles was made. Running with full EGR and less.
than one-half the NOx level required for 1973-75 the 1975 prototype
got 4% better fuel economy than the average of all 1973 certification
vehicles of the same weight. The Chrysler 1975 prototype demon-
strated a 6% improvement over its 1973 counterpart, the 360 CID
Plymouth.
1972 FTP
(All data in miles per gallon)
Vehicle MPG
Average of all 1973 certification 10.13
vehicles tested at 4500 I.
Average of 360 Plymouth 1973 9.92
certification cars (4500 I)
Average of last three car #333 10.5
at 4500 I with full EGR
Table II presents data on the "medium duty vehicle" simulation.
The hydrocarbon levels do not appear to be significantly different
than the levels achieved during the Igiht duty (passenger car)
testing. The HC levels are, however, somewhat questionable due
to the higher background levels present in our medium duty testing
area. HC measurement was difficult in bags two and three due to
the higher dilution rates obtained with the large medium duty CVS
unit. Carbon monoxide levels were somewhat higher than those
obtained during the light duty testing but a high degree of control
was maintained. The catalyst temperature gauge installed on the
vehicle indicated that there was no danger of overtemperature
during LA4 driving cycle operation. The vehicle had no difficulty
in keeping up with the speed vs. time trace at either.6000 or
7000 pounds test weight.
NOx emissions measured during medium duty operation were
significantly higher than NOx measured during light duty testing.
Tests were run at 6000 pounds with and without the EGR switch
turned on. The data indicates that the EGR system was just as
effective during the medium duty simulation as during the passenger
car testing. The EGR accounted for a 50% NOx decrease in both
cases.
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Table III presents the data recorded during 60 mph cruise
operation at the standard test weight of 4500 pounds. HC,
CO, and NOx emissions were very low and the fuel economy was
excellent.
When the driveability and performance of car #333 was compared
to a 1972 Plymouth Fury rental car (360 CID engine) no significant
differences were noticed. Neither vehicle had any adverse
driveability characteristics. The acceleration performance of
both vehicles was almost identical. Zero to sixty mile per hour
acceleration times were about 11.5 seconds for both cars.
Conclusions
1. After EGR rate was reduced, Chrysler prototype #333 demon=
strated the ability to achieve the emission levels required
for model year 1975 with high mileage on one catalyst and low
mileage on the other catalyst.
2. Reducing EGR rate caused significant increased in NOx emissions
and significant reductions in HC and CO emissions.
3. NOx emissions were a function of(vehicle test weight.
•An- 83% increase in weight (from 3000f to 5500#), caused
an 861 increase in NOx emissions.
4. HC and CO emissions did not change significantly as test
weight was varied.
5. The fuel economy of prototype #333 was better than the
fuel economy of the average 1973 certification vehicle of the
same weight.
6. The fuel consumption measured at different inertia weights
did not change drastically. This is probably due to more
efficient power to weight ratios at the higher loadings.
7. Reducing the EGR rate did not cause significant changes
in .fuel economy. This testing indicates that EGR systems
can be designed to reduce NOx emissions without adversely
affecting fuel consumption. The EGR system on car #333 was
a proportional system.
8. Exhaust emissions and fuel economy at 60 mph cruise condition
were both very good. Unlike many 1973 models and other advanced
prototypes tested, the Chrysler 1975 prototype did not have
provisions for switching off emission control systems when
conditions specific to the LA4 (Federal) driving cycle are not
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encountered. At 60 mph cruise the NOx emissions from car #333
were much lower than several 1976 prototypes previously tested
because NOx control was maintained. Catalyst temperatures at
60 mph cruise were lower than during portions•of the LA4 cycle.
There apparently is no need to bypass the catalyst system just
because expressway speeds are encountered. Fuel economy at
60 mph cruise calculated to be over 18 miles per gallon.
9. Overall a'cceleration performance and driveability of
car #333 was as good as the 1972 production counterpart.
10. Data from the "medium duty" simulation indicates that the
catalytic converters could maintain a high level of control
under much higher loading conditions than normally found in
passenger car operation. NOx levels were significantly higher
during the medium duty simulation but the EGR system was still
quite effective.
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TABLE I
1975 Federal Test Procedure
Call data in grams per mile)
Test Number
12-2368
12-2373
AVERAGE
3000# Inertia w/EGR
HC CO
.38
.39
.39
5.47
4.22
4.85
NOx
.88
1.05
.97
MPG
11.1
10.9
11.0
Test Number
12-2356
12-2361
12-2362
12-2393
12-2401
12-2409
12-2413
AVERAGE
AVERAGE of
Last Three
4500/f Inertia w/EGR
HC CO
.69
.65
.50
.44
.56
.44
.43
.53
.48
8.14
7.44
6.35
5.10
4.60
3.93
4.24
5.69
4.26
NOx
72
52
47
34
,34
43
32
1.45
1.36
MPG
10.6
10.3
10.5
9.9
10.4
10.9
11.5
10.6
10.9
Test Number
12-2399
12-2404
AVERAGE
4500# Inertia wo/EGR
HC CO
.31
.33
.32
3.76
2.80
3.28
NOx
2.51
2.92
2.72
MPG
10.8
11.2
11.0
Test Number
12-2379
12-2383
AVERAGE
5500# Inertia w/EGR
HC CO
.49
.51
.50
6.07
5.71
5.89
NOx
1.81
1.78
1.80
MPG
9.8
10.0
9.9
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TABLE II
1975 Federal Test Procedure
(all data in grams per mile)
Medium Duty Vehicle Simulation
6000# Inertia w/EGR
Test Number HC CO NOx MPG
12-2417
12-2419
AVERAGE
.20
.34
.27
4.99
5.89
5.44
3.52
3.39
3.46
8.52
8.63
8.57
6000# Inertia wo/EGR
Test Number HC_ CO NOx MPG
16-0009 .39 5.77 7.08 8.7
7000# Inertia w/EGR
Test Number HC CJD NOx MPG
18-0495 .39 6.74 4.86 7.4
18-0499 .21 8.32 4.50 8.1
AVERAGE .30 7.53 4.68 7.8
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TABLE III
60 MPH Steady State
(all data in grams per mile)
4500* Inertia w/EGR
HC CO NOx MPG
60 mph Cruise .07 1.40 1.01 18.7
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NOy LEVEL K INERTIA WEIGHT
"'CHRYSLER '75 PROTOTYPE WITH. EGR
3.0
CL
o
-j
2.0
^:
kj
-J
><
i
'-"
-76
HOOD 5000
INERT/A WEIGHT
FIGURE I.
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APPENDIX I
FEDERAL EMISSION TESTING PROCEDURES
FOR LIGHT DUTY VEHICLES '
The Federal procedures for emission testing of light
duty vehicles involves operating the vehicle on a chassis
dynamometer to simulate a 7.5 mile (1972 procedure) or
11.1 mile (1975 procedure) drive through an urban area.
The cycle is primarily made up of stop and go driving and
includes some operation at speeds up to 57 mph. The
average vehicle speed is approximately 20 mph. Both the
1972 and 1975 procedures capture the emissions generated
during a "cold start" (12-hour soak @ 68°F to 86°F before
start-up). The 1975 procedure also includes a "hot start"
after a ten minute shut-down following the first 7.5 miles
of driving.
Vehicle exhaust is drawn through a constant volume
sampler (CVS) during the test. The CVS dilutes the vehicle's
exhaust to a known constant volume jwith make up air. A
continuous sample of the diluted ex-haust is pumped into
sample bags during the test. •
Analysis of the diluted exhaust collected in the sample
bags is used to determine the mass of vehicle emissions per
mile of operation (grams per mile). A flame ionization de-
tector (FID) is used to measure unburned hydrocarbon (HC) •
concentrations. Non-dispersive infrared (NDIR) analyzers are
used to measure carbon monoxide (CO) and carbon dioxide (C02).
A chemiluminescence (CL) analyzer is used to determine oxides .
of nitrogen (NOx) levels.
These procedures are used for all motor vehicles designed
primarily for transportation of property and rated at 6,000
pounds GVW or less, or designed primarily for transportation of
persons and having a :capacity of twelve persons or less. Each
new light duty vehicle sold in the United States in model years
1973 and 1974 must emit no more than 3.4 gpm HC, 39. gpm CO
and 3.0 gpm NOx when using the 1972 procedure. In 1975 the
standards will change to .41 gpm HC. 3.4 gpm CO and 3.1 gpm NOx
using the 1975 procedure. In 1976 the standards will be .41
gpm HC, 3.4 gpm CO and .4 gpm NOx using the 1975 procedure.
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