75-25 GS
Test Results on a
1975 California Vega
Equipped with the Gould Dual-Catalyst
Emission Control System
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 Gould "Corporation, New Business Division of Cleveland, Ohio
requested confirmatory testing of a 1975 California Vega equipped with
their catalyst system. As part of a continuing program for the eval-
uation of new developments in emission control, the Emission
Control Technology Division agreed to test the vehicle. Arrangements
were made with Mr. Richard Steiner of Gould, to test the vehicle
on May 6, 1975.
The Environmental Protection Agency receives information about many
devices for which emission reduction or fuel economy improvement claims
are made. In some cases, both claims are made for a single device. In
most cases, these devices are being recommended or promoted for retrofit
to existing vehicles although some represent advanced systems for
meeting future standards.
The EPA is interested in evaluating the validity of the claims for
all such devices, because of the obvious benefits to the Nation of
identifying devices that live up to their claims. For that reason the
EPA invites proponents of such devices to provide to the EPA complete
technical data on the device's principle of operation, together with
test data on the device made by independent laboratories. In those cases
in which review by EPA technical staff suggests that the data submitted
holds promise of confirming the claims made for the device, confirmatory
tests of the device are scheduled at the EPA Emissions Laboratory at Ann
Arbor, Michigan. The results of all such confirmatory 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 confirmatory tests are neces-
sarily of limited applicability. A complete evaluation of the effective-
ness of an emission control system in achieving its claimed 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 confirmatory test projects conducted by EPA. I/ For
promising devices it is necessary that more extensive test programs be
carried out.
The conclusions from the EPA confirmatory tests can be considered
to be quantitatively valid only for the specific type of vehicle used in
the EPA confirmatory test program. Although it is reasonable to
I/ See Federal Register 38 FR 11334, 3/27/74, for a description
of the test protocols proposed for definitive evaluations of
the effectiveness of retrofit devices.
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extrapolate the results from the EPA confirmatory 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,
tests of the device on such other vehicles would be required to reliably
quantify results on other types of vehicles.
In summary, a device that lives up to its claims in the EPA confirma-
tory test must be further tested according to protocols described in
footnote I/, to quantify its beneficial effects on a broad range of
vehicles. A device which when tested by EPA does not meet the claimed
results would not appear to be a worthwhile candidate for such further
testing from the standpoint of the likelihood of ultimately validating
the claims made. However, a definitive quantitative evaluation of its
effectiveness on a broad range of vehicle types would equally require
further tests in accordance with footnote I/.
System Description
The test vehicle was a 1975 Vega Notchback (2 door sedan) produced
in compliance with the 1975 California vehicle emissions standards. See
Table I for vehicle description. The vehicle as tested had an odometer
reading of 6,610 miles. The modifications had been made shortly before
our tests, thus the system tested was a "zero mile" modification to a
"stabilized" vehicle.
Exhaust emissions were controlled by a Gould Getter catalyst system
employing three catalyst beds. (See Figures 1 and 2). The first bed,
a small Engelhard PTX-IIB catalyst, removed oxygen and provided early
cold start-up hydrocarbon and carbon monoxide oxidation. The second
bed, a Gould Gem 68 catalyst, reduced nitrogen oxides. After the second
bed, secondary air was injected into the exhaust gas to provide suf-
ficient oxygen for oxidation of the remaining hydrocarbons and carbon
monoxide in the third bed, an Engelhard PTX-IIB monolith. Air injection
after the Gem catalyst was continuous, while air injection to the exhaust
ports was limited to 60 seconds during cold starts. The standard
exhaust gas recirculation (EGR) was not changed. Ignition timing at
idle was increased from 12° BTDC to 18° BTDC. An anti-stall device was
installed to override the thermal check arid delay valve which normally
shuts off vacuum advance during cold starts. The anti-stall override
was activated when a stall was determined to be iminent by sensing
manifold vacuum. Carburetor adjustments made are listed in Table II.
These adjustments, though minor, provided leaner carburetion. The
evaporative emission canister was disconnected.
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Table I
Test Vehicle Description
Chassis model year/make - 1975 Chevrolet Vega Notchback
Engine
type 4 stroke Otto cycle, Overhead cam, in-line
4 cyl.
bore x stroke 3.50 x 3.63 in/88.9 x 92.2 mm
displacement 140 CID/2,294 cc
compression ratio 7.9:1
maximum power @ rpm 80 hp/60 kW @ 4400 rpm
fuel metering 2-V carburetor
Drive Train
transmission type 3 speed automatic
final drive ratio . 2.92:1
Chassis
type unitized construction, front engine,
rear wheel drive
tire size BR 78-13
curb weight 2540 lb/1152 kg
inertia weight 2750 lb/1247 kg
passenger capacity 4
Emission Control System
basic type reduction catalyst (GEM 68), oxidation
catalyst (Engelhard PTX-IIB), air injection
exhaust gas recirculation, positive crankcase
ventilation
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FIGURE 1
GOULD GETTER SYSTEM
o Distributor
- 18° BTDC at Idle
- Anti-stall override of thermal
check valve on vacuum advance
o Carburetor
- Minor adjustments
See Table II
0 EC/CO oxidation/
catalyst (PTX IIB)
o.NOx reduction catalyst
(GEM 68)
o Oxygen removal catalyst
(1/2 PTX IIB)
12V solenoid for
port air control
Air pump
o Air injection scheme
— Cold start
60 second port injection
2-3% residual Q£ at catalyst
- Continuous secondary
injection oxidation catalyst
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FIGURE 2
GOULD CATALYST SYSTEM
DIMENSIONS.IN INCHES
(centimeters)
Oxygen removal catalyst
Engelhard PTX-IIB
(monolith)
2.25
Secondary air injection
10.75
(27.3)
Oxidation catalyst
Engelhard PTX-IIB
(monolith)
NOx reduction catalyst
GEM 68
(wound expanded metal mesh)
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Test Procedures and Results
The testing consisted of one 1975 Federal Test Procedure ('75 FTP)
described in the Federal Register of November 15, 1972; and one EPA
Highway Cycle (HWC), described in the EPA Recommended Practices for
Conducting Highway Fuel Economy Tests. Both of these tests are conducted
on a chassis dynamometer and employ the Constant Volume Sampling (CVS)
procedure, which gives exhaust emissions of HC, CO, NOx and CO- in grams
per mile. Fuel economy is calculated by the carbon balance method. The
fuel used was Indolene unleaded 96 RON gasoline.
The results of these tests are shown in Tables III, IV and V.
Conclusions
The hydrocarbon and carbon monoxide emissions on the '75 FTP from
this "zero mile" system were well within the statutory 1978 standards
of 0.41 grams per mile and 3.4 grams per mile respectively. The NOx
emissions of .42 slightly exceeded the statutory '78 standard of 0.4
grams per mile. The ability of this system to approach the statutory
'78 standards and still maintain or slightly improve upon the fuel
economy of the 1975 Vega is promising. This coupled with the relative
simplicity of the system and its compatibility with existing control
hardware and calibrations make it an attractive emission control
package. As this was a "zero mile" test the durability of the system
and its ability to maintain emission levels with mileage accumulation
have yet to be demonstrated.
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Table II
Carburetor Adjustments
Primary main jet
Primary air bleed
Carburetor idle (D)
Choke index
Choke pulldown
Choke delay restriction
Cold idle speed (N)
Stock
0.0535"
0.065"
750 rpm
4-rich
0.186"
Stock
1600 rpm
Gould NOx System
0.0530"
0.072"
800 rpm
1-lean
0.260"
removed
1800 rpm
Table III
Gould Vega '75 FTP Individual Bag and
EPA Highway Cycle Mass Emissions
grams per mile
(grams per kilometre)
Test Cycle
'75 FTP Cold Transient
'75 FTP Cold Stabilized
'75 FTP Hot Transient
EPA Highway
HC
CO
0.52 3.27 499
(0.32) (2.03) (310)
0.19 0.02 451
(0.12) (0.01) (280)
0.19 0.08 408
(0.12) (0.05) (253)
0.11 0.03 306
(0.07) (0.02) (190)
NOx
0.59
(0.37)
0.33
(0.21)
0.46
(0.29)
0.29
(0.18)
Fuel Economy
(Fuel Consumption)
17.5 miles/gal
(13.4 litres/100 Km)
19.7 miles/gal
(11.9 litres/100 Km)
21.7 miles/gal
(10.8 litres/100 gal
29.0 miles/gal
(8.11 litres/100 gal
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Table IV
75 FTP Composite Mass Emissions
grams per mile
(grams per kilometre)
HC
CO
CCv
Gould Vega
1975 Calif. Standard
1978 Federal
Statutory Standard
0.26 0.71 449
(0.16) (0.44) (279)
0.9 9.0
(0.56) (5.6)
0.41 3.4
(0.25) (2.1)
SOx
0.42
(0.26)
2.0
(1.24)
0.4
(0.25)
Table V
'75 FTP (City) and HWC (Highway) Fuel Economies/Fuel Consumption
miles per gallon
(litres per 100 kilometres)
Gould Vega
EPA Certification Vega
Cit5
19.7
(11.9)
19
(12.4)
Highway
29.0
(8.1)
28
(8.4)
* As published in the 1975 EPA Gas Mileage Guide for
New Car Buyers in California.
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