EPA-AA-TAEB 76-14
Exhaust Emissions and Fuel Economy
of a Ford Pinto Powered by a Nissan Diesel Engine
March 1976
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 system's principle of operation, 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 Motor Vehicle Emission
Laboratory at Ann Arbor, Michigan. The results of all such test pro-
jects 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 test 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.
In October of 1975, the Wilcap Company of Torrance, California
offered to allow the EPA to test a Ford Pinto retrofitted with a 4-
cylinder Diesel engine. This particular vehicle had been entered in a
Student-Engineered Economy Design Rally sponsored by the University of
California and Western Washington State College. The Pinto-Diesel won
the overall fuel economy category and demonstrated exhaust emissions
below the 1977 Federal Emission Standards.
Vehicle Description
The test vehicle is a 1971.Ford Pinto sedan, powered by a Chrysler-
Nissan CN4-33 Diesel engine with a displacement of 132 cu. in. The
engine has a prechamber type of combustion chamber and is equipped with
glow plugs. The fuel pump is manufactured by C.A.V. Lucas. Test inertia
weight was 2750 Ibs.
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The vehicle is equipped with a four-speed manual transmission and
an axle-mounted Hone overdrive. The axle ratio is 2.80 without over-
drive and 1.95 with the overdrive engaged. Oversize tires (225R x 15)
have been fitted to the rear axle.
Engine cooling is accomplished with an oversize radiator. No
engine cooling fan is fitted.
A tabulation of vehicle characteristics is given on the Vehicle
Description Sheet at the end of this report.
Test Program
Exhaust emission tests were conducted in accordance with the 1975
Federal Test Procedure ("75 FTP) for light-duty Diesel vehicles. In
addition to the '75 FTP, exhaust emissions and fuel economy were measured
over the EPA Highway Fuel Economy Test (HFET) and under steady state
operating conditions. Other testing included measurement of sulfate
emissions and acceleration times.
The vehicle was tested at steady state speeds of 0 (idle), 15, 30,
45 and 60 mph. At 45 and 60 mph, the vehicle was tested with and with-
out the overdrive engaged.
One HFET was run using the overdrive. The vehicle was shifted into
overdrive when a cruise speed of 50 mph was attained. This allowed the
overdrive to be used for about one half of the Highway Cycle. The
shift into overdrive was made at about 325 seconds into the HFET.
Overdrive was not used during the LA4.
Sulfate emissions were measured over the EPA Sulfate Cycle (SC-7).
Eight such tests were run. The fuel used for the sulfate testing was #2
Diesel fuel containing 0.21 wt. % sulfur. A description of the pro-
cedure used for measuring sulfate emissions is given on page 11.
Acceleration times from 0-60 mph and 40-60 mph were measured.
Accelerations from 40-60 mph were run in 4th gear, with and without
overdrive engaged.
Test Results
The Diesel-Pinto demonstrated the following exhaust emissions and
fuel economy:
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'75 FTP Composite Mass Emissions
grams per mile
(grams per kilometer)
Average of
2 tests
HC
0.54
(0.34)
CO
1.13
(0.70)
NOx
0.74
(0.46)
Fuel Economy
(Fuel Consumption)
46.1 mpg
(5.1 liters/100 km)
The exhaust emissions are well within the 1977 Federal emission
standards (HC - 1.5 gpm, CO - 15.0 gpm, NOx -2.0 gpm). HC and NOx
emissions are above the 1978 Federal standards of 0.41 gpm and 0.4 gpm
respectively.
Exhaust emissions and fuel economy measured over the EPA Highway
Driving Cycle are presented in the following table:
EPA Highway Fuel Economy Test
grams per mile
(grams per kilometer)
Fuel Economy
HC CO NOx (Fuel Consumption)
0.24 0.77 0.63 60.3 mpg
(0.15) (0.48) (0.39) (3.9 liters/100 km)
0.18 0.44 0.63 63.9 mpg
(0.11) (0.27) (0.39) (3.7 liters/100 km)
Without overdrive
avg. of 2 tests
with overdrive
1 test
Steady state emissions and fuel economy are presented in Table IV.
It should be noted that steady states are generally not representative
of real-world driving conditions. The purpose of steady state testing
is to give insight into operating characteristics of the test vehicle.
The '75 FTP and Highway fuel economies can be combined into a
single fuel economy using weighting factors that have been determined by
the Department of Transportation to be typical of the driving pattern in
the United States. These factors are 55% for the '75 FTP and 45% for
the HFET. The '75 FTP and HFET fuel economies are averaged harmonically
to yield the combined fuel economy, which for the Diesel-Pinto is 51.6
mpg (4.6 liters/100 km).
Sulfate emissions measured over the EPA sulfate cycle are presented
in Table V. Emissions of SO, are in milligrams per mile. The percent
of fuel sulfur that is converted to SO. is also shown in Table V.
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The acceleration time from 0-60 mph is 22.5 seconds. Acceleration
from 40-60 mph in 4th gear takes 17.5 seconds. From 40-60 mph in 4th
gear overdrive takes 57.5 seconds.
Road testing revealed that the Diesel-Pinto had adequate acceleration
capability provided that overdrive was not used. It was not practical
to use 4th gear overdrive below 60 mph because the engine had insufficient
power in the engine speed range in which it was operating. Since road
testing was conducted on public roads, no attempt was made to determine
whether the overdrive could be used at speeds above 60 mph.
The oversize tires fitted to the rear of the Diesel-Pinto had an
adverse effect on the handling of the vehicle. In addition, apparent
adjustments to the front suspension to increase ground clearance also
caused a degradation of steering response characteristics.
Discussion
It appears that much of the credit for the high fuel economy of the
Diesel-Pinto (compared to other Diesel-powered passenger cars) is due to
modifications to the vehicle to reduce the number of engine revolutions
per mile traveled (N/V ratio). For instance, changing from standard A78
x 13 rear tires to the oversize 225 x 15 tires results in a reduction in
N/V ratio of roughly 18%. EPA and DOT test data indicate that the
change in composite fuel economy due to this change in N/V ratio will
probably be 9-18%. So, without the oversize tires, the composite fuel
economy can be expected to be between 42.3 mpg and 47.0 mpg.
The following table compares the exhaust emissions and fuel economy
of the Diesel-Pinto to those of a Diesel-powered Volkswagen Rabbit
tested by the EPA. The Diesel Rabbit is the only other Diesel-powered
car tested by EPA that has had an equivalent power-to-weight ratio.
'75 FTP Mass Emissions
grams per mile
(grams per kilometer)
Diesel-Pinto
VW Rabbit
HC
0.54
(0.34)
CO
1.13
(0.70)
NOx
0.74
(0.46)
0.19 0.98 1.19
(0.12) (0.61) (0.74)
Composite
Fuel Economy Inertia
(Fuel Consumption) Class
51.6 mpg
(4.6 liters/100 km) 2750 Ibs.
41.5 mpg
(5.7 liters/100 km) 2250 Ibs.
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The Rabbit is powered by a 4 cylinder, 4 stroke Diesel engine that
developes 50 hp. The transmission is a manual 4 speed, and the final
drive ratio is 4.22:1. Acceleration time from 0-60 mph was 16.5 seconds.
The road load at 50 mph used for the Diesel-Rabbit test was 7.3 hp.
The road load for the Diesel-Pinto was 9.9 hp. Road load effects on
fuel economy are seen primarily during the HFET. During the '75 FTP,
change in fuel economy due to small changes in road load is negligible.
It is true that the Diesel-Pinto delivers substantially better fuel
economy than other passenger cars, but the Diesel-Pinto also utilizes
fairly extensive vehicle (not engine) modifications to achieve its high
fuel economy. These modifications adversely affect the handling and
roadability of the Diesel-Pinto.
Conclusions
1. The Diesel-Pinto demonstrated exhaust emissions below the
levels required by the 1977 Federal emission standards for light-duty
vehicles.
2. The Diesel-Pinto has higher fuel economy than any other passenger
car tested to date by the EPA. However, much of the credit for this
high fuel economy is due to modifications to the vehicle to reduce the
number of engine revolutions per mile traveled.
3. Some of the chassis adjustments to.improve fuel economy and
facilitate the Diesel engine installation resulted in steering response
characteristics which may seriously compromise handling in emergency
situations.
4. It is not practical to operate the Diesel-Pinto in 4th gear
overdrive at speeds under 60 mph.
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Test //
77-551
77-550
Average
Table I
1975 Federal Test Procedure
Mass Emissions in
grams per Mile
(grams per kilometer)
HC
CO
C0r
0.50 1.06 218.
(0.31) (0.66) (135.)
0.58 1.19 218.
(0.36) (0.74) (135.)
0.54 1.13 218.
(0.34) (0.70) (135.)
NOx
0.72
(0.45)
0.75
(0.47)
0.74
(0.46)
miles/gallon
(liters/100 kilometers)
46.2
(5.1)
45.9
(5.1)
46.1
(5.1)
Test #
without overdrive
77-548
77-549
Average
with overdrive
77-547
Table II
EPA Highway Fuel Economy Test
Mass Emissions in
grams per Mile
(grams per kilometer)
HC
CO
CO,.
0.23 0.77 169.
(0.14) (0.48) (105.)
0.24 0.77 165.
(0.15) (0.48) (103.)
0.24 0.77 167.
(0.15) (0.48) (104.)
0.18 0.44 158.
(0.11) (0.27) (98.)
NOx
0.62
(0.39)
0.63
(0.39)
0.63
(0.39)
0.63
(0.39)
miles/gallon
(liters/100 kilometers)
59.6
(3.9)
60.9
(3.9)
60.3
(3.9)
63.9
(3.7)
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Table III
1975 FTP Individual Bag Emissions in grams per mile
1: Cold Transient Bag 2: Stabilized Bag 3: Hot Transient
Test # HC CO CCL NOx MPG HC CO CO,, NOx MPG HC CO CO,, NOx MPG
77-551 0.72 1.31 246. 0.72 40.9 0.51 1.05 210. 0.73 48.0 0.31 0.91 212. 0.70 47.5
77-550 0.77 1.45 243. 0.74 41.0 0.60 1.19 212. 0.77 47.2 0.38 0.99 212. 0.72 47.4
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Table IV
Steady State Mass Emissions in
grains per mile
(grams per kilometer)
Speed
Idle (300 sees.)
15 mph/24 kph 2nd gear
30 mph/48 kph 4th gear
45 mph/72 kph 4th gear
45 mph/72 kph 4th gear
overdrive
HC
CO
CO,
NOx mpg (H/100 km)
0.18 gms 0.60 gms 80. gms 0.32 gms
0.23 1.16 139. 0.47
(0.14) (0.72) (86.) (0.29)
0.11
(0.07)
0.22
(0.14)
60 mph/97 kph 4th gear
60 mph/97 kph 4th gear
overdrive
0.09
(0.06)
0.26
(0.16)
0.51
(0.32)
0.66
(0.41)
0.32
(0.20)
0.92
(0.57)
112.
(70.)
138.
(86.)
125.
(78.)
187.
(116.)
0.49
(0.30)
0.60
(0.37)
0.67
(0.42)
0.73
(0.45)
72.0 mpg
(3.3 A/100 km)
89.8 mpg
(2.6 £/100 km)
72.9 mpg
(3.2 «,/100 km)
80.8 mpg
(2.9 Jl/100 km)
53.9 mpg
(4.4 fc/100 km)
0.10
(0.06)
0.22 163.
(0.14) (101.)
0.74
(0.46)
62.3 mpg
(3.8 a/100 km)
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Table V
Sulfuric Acid Emissions in
milligrams per mile
milligrams % of Fuel Sulfur
H2S04 Converted to S04
8.5 1.8
6.4 1.5
12.5 2.5
10.6 2.1
6.6 1.5
5.6 1.3
8.2 1.8
10.0 2.1
Average 8.6 1.8
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10
TEST VEHICLE DESCRIPTION
Chassis model year/make - 1971 Ford Pinto
Emission control system - None
Engine
type t ...... 4-stroke, Diesel, 1-4, ohv, indirect injection
bore x stroke* .' ..'**.*! .' ." ! 3.277 x 3.94 in/83.2 x 100.1 mm
displacement 132 cu. in./2163cc
compression ratio 22:1
maximum power @ rpm 61 bhp at 4000 rpm/46kW at 4000 rpm
fuel metering mechanical fuel injection
fuel requirement #2 Diesel
Drive Train
transmission type 4-speed manual
final drive ratio 2.8 without overdrive
1.95 with overdrive
Chassis
type front engine, rear wheel drive
tire size 225R x 15 (rear)
curb weight 2480 lbs/1125kg
inertia weight 2750 Ibs.
passenger capacity 4
Emission Control System
basic type none
durability accumulated on system. . 75,000 miles/121,000km
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11
Diesel-Pinto
Procedure used to Measure Sulfate Emissions
1. The fuel was drained from the test vehicle. The vehicle was re-
fueled with #2 Diesel fuel containing 0.21 wt. % sulfur. This fuel was
used throughout the sulfate testing.
2. The vehicle was driven over one LA-4 cycle with the test fuel in
preparation for the test series.
3. The following sequence of test cycles was used to measure sulfate
emissions.
a) Cold start '75 FTP
b) Two hot start sulfate cycles
c) One EPA Highway Driving Cycle
d) Two hot start sulfate cycles.
This sequence was run on two consecutive days.
4. The barium chloranilate procedure was used to determine the con-
centration of sulfates in the exhaust.
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