75-24 BM
Evaluation of the NCAC Dual Catalyst Pinto
May 1975
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 National Clean Air Coalition (NCAC), a non-profit environmental
organization, contacted the Environmental Protection Agency about a pro-
totype emission control system they had developed and had operating on
a 1974 Ford Pinto. The system was aimed at emission levels of .41 grams
per mile hydrocarbons (HC), 3.4 grams per mile carbon monoxide (CO),
and .4 grams per mile oxides of nitrogen (NOx). Confirmatory testing
at the EPA laboratory was requested, and the Emission Control Technology
Division agreed to conduct an evaluation test program as part of its
continual technology assessment function.
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.
EPA1s 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,1or both. EPA invites developers of such systems to provide
to the EPA complete technical data on the system's 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 programs 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 oh
other types of vehicles.
System Description
The vehicle tested was a 1974 Ford Pinto with a four-cylinder
122 CID (2000 cc) engine and four-speed manual transmission. Curb
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weight of the vehicle as tested was 2580 Ibs. A complete vehicle
description is given in the vehicle description table on the following
page.
Exhaust emissions are controlled by a dual catalyst system in which
a Gould GEM 67 NOx reduction catalyst is followed by a Matthey-Bishop
oxidation catalyst. Air is injected:ahead of each catalyst and also,
on cold starts, at the exhaust ports for 120 seconds. The Gould catalyst
used was not,the latest Gould Getter catalyst which employs an-oxygen
removal catalyst ahead of, and in the same canister as, the NOx reduction
catalyst. (The purpose of the small oxidation catalyst in the "Getter"
system is to prevent any oxygen "spikes"-momentary increases in oxygen
concentration-from entering the NOx catalyst. This insures a proper
reduction atmosphere for:the NOx catalyst and lengthens durability.) The
reduction catalyst, in both cases, is a base metal composition (containing
nickel) on a metallic substrate.
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The air pump was not a standard item on the vehicle, but was installed
by the developer with this system. The standard exhaust gas recircu-
lation unit was disconnected and none was used on the system. A modified
Holley carburetor was installed and calibrated to deliver a raw (in
the exhaust manifold without air injection) CO concentration of 2-2%
percent throughput the entire operating range. This is a richer mixture
than the standard carburetor gave and is necessary in order to maintain
an abundance of carbon monoxide at the entrance to the NOx reduction
catalyst. The distributor" timing curve was modified, the basic timing
was increased from 6° to 10° BTDC, and full vacuum advance was utilized.
Test Procedure
Exhaust emissions tests were conducted according to the 1975 Federal
Test Procedure ('75 FTP), "described in the Federal Register of
November 15, 1972. An additional test on the EPA Highway Cycle was run.
All tests were conducted using an inertia weight of 2750 Ibs (1248 kg)
with a road load setting of 9.9 horsepower (7.39 kW) at 50 miles per
hour (80.5 km/hr).
The vehicle was driven to the EPA laboratory from Buffalo, New York,
and no calibration changes were made to the vehicle either when it arrived
or before any of the tests. Two '75 FTP's and one EPA Highway Cycle were
run on the vehicle.
At the request of NCAC personnel, the engineer who drove the vehicle
to the EPA laboratory, who was familiar with the test procedures, drove
the vehicle during the first '75 FTP. Also at the request of NCAC, the
fuel used during the test program was Amoco Super Premium, a high
octane lead-free gasoline. The vehicle had been run exclusively on this
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TEST VEHICLE DESCRIPTION
Chassis model year/make - 1974 Pinto
Emission control system - Dual catalyst
Engine
type 4 stroke Otto cycle, OHC, 4 cyl, in-line
bore x stroke 3.57 x 3.03 in./90.7 x 77 mm
displacement 122 CID/2000 cc
compression ratio 8.2:1
maximum power @ rpm ......... not available
fuel metering Holley modified carburetor
fuel requirement 91 RON unleaded
Drive Train
transmission type . . 4 speed manual
final drive ratio 3.40
Chassis
type . . jnitized construction, front engine, rear
wheel drive, 2 door coupe
tire size A 78-13
curb weight 2580 lbs/1171 Kg
inertia weight 2750 lbs/1248 Kg
passenger capacity 4
Emission Control System
basic type reduction catalyst, oxidation catalyst
oxidation catalyst location exhaust system, under floor
make Matthey-Bishop
reduction catalyst location ..... exhaust system, near firewall
make Gould GEM 67
EGR type None
air injection stock Ford, geared lower than normal
additional features
durability accumulated on system . . . about 7000 miles except for oxidation
catalyst about 2500 miles
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fuel and since it has a different density, from Indolene Clear, a
standard test fuel used at the EPA laboratory, EPA was asked not to
change fuels. Changing to Indolene would have required a recalibration
of the special carburetor to assure the same air-fuel ratio. The
higher density and higher carbon fraction of hydrocarbons were accounted
for in calculating fuel economy and hydrocarbon emissions from the
vehicle.
Test Results
Exhaust emissions data, summarized below, illustrate that the NCAC
vehicle achieved the levels of emissions required by the 1978 Federal
standards. Complete emissions data, including individual bag results,
are listed in the Appendix.
175 FTP Composite Mass Emissions
grams per mile
(grams per kilometre)
Fuel Economy, miles/gallon
HC CO NOx (Fuel Consumption, litres/100 km)
NCAC vehicle .28 2.20 .35 20.1
avg. of 2 tests (.17) (1.36)(.22) (11.7)
1978 Federal .41 3.4 .4
emissions standards (.25) (2.1) (.25)
EPA Highway Cycle Mass Emissions
grams per mile
(grams per kilometre)
Fuel Economy, miles/gallon
HC CO NOx (Fuel Consumption, litres/100 km)
NCAC vehicle .10 .04 .17 30.8
1 test (.06) (.02)(.11) (7.64)
Data from Bags 1 and 2 of the '75 FTP1s have been used to calculate
'72 FTP mass emissions and fuel economy, for comparison with the "baseline"
1974 certification Pinto of the same type: 122 CID, manual 4-speed
transmission, 2750 Ibs. IW class. (The 72 FTP was the test procedure
used for certification of 1972 through 1974 model year cars.)
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• 72 FTP Mass Emissions
grams per mile
(grams per kilometre)
HC
CO
NOx
NCAC vehicle
avg. of 2 tests
1974 Certification
vehicle
.38 4.86 .52
(.24) (3.02) (.32)
2.9 24 1.8
(1.8) (14.9) (1.1)
Fuel Economy, miles/gallon
(Fuel Consumption, litres/100 km)
19.4
(12.1)
22.8
(10.3)
It is seen that on the 72 FTP the NCAC vehicle demonstrated good
control of pollutant emissions, at the expense of a 15 percent drop in
fuel economy compared to the 1974 certification Pinto.
Vehicle driveability was very good. It started easily, did not
stumble or stall, and was fairly responsive. No acceleration tests were
performed, but it seemed to have comparable power to the standard
Pinto and had no trouble keeping up with the driver's trace used in
the '75 FTP.
Conclusions
Operating on a non-standard fuel, the NCAC Pinto, with over 7000
accumulated miles on the system (except for the oxidation catalyst,
which had accumulated about 2500 miles), met the 1978 Federal emission
standards with a decrease (15 percent) in fuel economy compared to a
standard 1974 Pinto with the same engine and transmission.
In order to get a more rigorous comparison to other vehicles tested
by EPA, the car should be calibrated to operate on the standard unleaded
Indolene test fuel. Additional durability testing would also be needed
to determine if the system is capable of meeting the standards at 50,000
miles, which would be necessary for certification. The NOx emissions
would have to be reduced slightly to give high confidence of passing
certification testing, but it is reasonable to expect this reduction'
with additional modifications to the basic engine. The test vehicle
did not utilize any EGR which might help to give superior NOx control.
Since the timing was advanced farther than manufacturer's specifications
it would be desirable to check for a possible knock problem with 91
RON unleaded gasoline (the Amoco is 100 RON).
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It is our technical judgement that increasing the fuel economy
of the system should be the major future effort, because the NCAC vehicle
compares poorly in fuel economy with other vehicles that have achieved
.4 gpm NOx in tests at EPA. Examples are a dual-catalyst modification
by Gould of a 1975 Vega and a 1974 Pinto fittldvwith a- Questor base-metal
catalyst system built by PPG Industries. The,fuel economy of the Gould
Vega (as presented in TAEB Test Report No. 75^25) was .slightly better
than the EPA certification value for the 1975 California Vega. The PPG-
Questor Pinto, the subject of TAEB Report No. 75-20, had no loss in fuel
economy when compared to the certification value for the 1974 Pinto
built to meet California standards.
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Appendix
Table I
'75 FTP Composite Results
Mass Emissions, grams per mile
Fuel Economy, miles per gallon
lest INO. no i.u lAJn «VHk ruex di;uuuiuy
16-8966
15-8977
.27
.28
2.06
2.33
479
456
.37
.33
19.7
20.6
Table II
EPA Highway Cycle
Mass Emissions, grams per mile
Fuel Economy, miles per gallon
Test No.
15-8977
HC
.10
CO
.04
co2
307
NOx
.17
Fuel Economy
30.8
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Table III
Test Number
Bag 1 Cold Transient
HC CO C02 NOx
'75 FTP Individual Bag Results
Mass Emissions, grams per mile
Fuel Economy, miles per gallon
Fuel
Economy
Bag 2 Hot Stabilized
HC
CO
CO,
H\S \J\S .wW f\
NOx
Fuel
Economy
Bag 3 Hot Transient
HC CO C02 NOx
Fuel
Economy
16-8966
15-8977
.61 9.46 459 1.00 19.9
.63 10.84 484
.92 18.8
.14 .00 497 .12 19.0
.13 .00 467 .10 20.3
.27 .42 461 .36 20.5
.31 .35 413 .33 22.9
Test Number
16-8966
15-8977
Table IV
'72 FTP
Mass Emissions, grams per mile
Fuel Economy, miles per gallon
HC CO C02 NOx
.38 4.53 478.93 .54
.38 5.19 475.36 .49
Fuel Economy
19.4
19.5
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