EPA-AA-TAEB 75-4
Emission Results from a Prototype
Audi Fox
August 1974
Technology Assessment and Evaluation Branch
Emission Control Technology Division
Mobile Source Air Pollution Control Program
Office of Air and Waste Management Programs
Environmental Protection Agency
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Background
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 necessarily
of limited applicability. A complete evaluation of the effectiveness of
an emission control system in achieving its claimed performance improvements
Dn 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. \J 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 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 confirmatory
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/.
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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The Emission Control Technology Division of the Office of
Mobile Source Air Pollution Control was contacted by representatives
of Audi NSU Auto Union AG about testing a prototype Audi vehicle.
Consistent with ECTD's continuing interest in the evaluation of
advanced automotive emission control technology, a test program
was conducted by the Technology Assessment and Evaluation Branch.
Vehicle Description
The vehicle tested was a catalyst-equipped Audi Fox proto-
type, with a 4-cylinder 97 cubic inch engine and 4-speed manual
transmission. The car is described in detail in the Vehicle
Description table on the following page.
The emission control system consists of a three-way catalytic
exhaust reactor. This single catalytic unit is used for the control
of hydrocarbons, carbon monoxide and nitrogen oxide emissions.
The catalyst on this prototype Audi had experienced less than 100
miles (160 Km) of use.
To achieve control of all three pollutants at once in the same
reactor requires close control of the engine air-fuel ratio at a point
very near to stoichiometric. This degree of control is achieved using
the signal from an oxygen sensor in the exhaust stream to control a
Bosch K-Jetronic continuous-type fuel injection system in a closed
loop system.
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. Additional tests included the '72 FTP and
the EPA Highway Cycle. All tests were conducted using an inertia
weight of 2500 Ibs, (1133 kg) with a road load setting of 7.0 horse-
power (5.22 kw) at 50 miles per hour (80.5 km/hr). This road load
is lower than the 9.4 hp specified in the Federal Register for vehicles
in the- 2500-lb inertia weight class. The specified road load is to be
used unless a manufacturer chooses to determine road load by measuring
absolute manifold pressure on the road at 50 mph and duplicating that
pressure on the chassis dynamometer. This has been done by Audi, who
found that their road load was only 7 hp at 50 mph, due in part perhaps
to lower air resistance for the Audi vehicle than "typical" vehicles
on which the standard horsepower settings were based.
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TEST VEHICLE DESCRIPTION
Chassis model year/make - 1974 Audi Fox
Emission control system - 3-way catalyst
Engine
type 4-cycle, OHC, 14, otto cycle
bore x stroke 3.13" x 3.15" (79.5mm x 80mm)
displacement '97 CID (1580cc)
compression ratio 8.0
maximum power @ rpra 79 hp @, 5800 rpip , , . . . _
, , „ . . Bosch, K-Jetrofiic mech. fuel injection
fuel metering . with fexh. 02 sensor
fuel requirement .' 91 RON unleaded
Drive Train
transmission type ......... 4 speed manual
final drive ratio 4.11
Chassis
type unit body construction
tire size 155.13 radials
curb weight . 2100 Ibs. (935 Kg)
inertia weight , . 2500 Ibs. (1110 Kg)
passenger capacity . . ^
Emission Control System
basic type ........ 3-way catalyst
substrate. .... monolith
volume 75 in3 (1220cc)
loading. ............. experimental state
durability accumulated on system.
100 mi (160 Km)
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Test Results
Exhaust emissions data, listed in Tables I and II, illustrate
the ability of the test car to achieve 1977 standards at low mileage.
Nitrogen oxide emissions were about twice as high as required by
the 1978 standard of 0.4 grams/mile (0.25 gm/km).
Conclusions
A low mileage Audi Fox prototype equipped with fuel injection
and a 3-way catalytic reactor system achieved 1977 emission levels,
tiith NOx emissions below 1 gram per mile. The fuel economy of this
low emission prototype was not significantly different from the
1974 production version of the1 Audi Fox.
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6
Table I
Exhaust Emissions (grams per mile)
and Fuel Economy (miles per gallon)
from a Prototype Audi Fox
(English Units)
Procedure
HC
CO
NOx
Fuel Economy
Urban Highway
•75 FTP
'75 FTP
Average
'77 Federal
Standards
'72 FTP hot start
'72 FTP hot start
'72 FTP hot start
Average
Highway Cycle
Highway Cycle
Average
0.15
0.14
0.14
0.41
0.09
0.08
0.10
0.09
0.06
0.05
0.06
0.95
0.94
0.95
3.4
0.36
0.38
0.40
0.38
0.33
0.33
0.33
0.82 22.0
0.94 21.8
0.88 21.9
2.00
0.70 22.5
0.56 22.3
0.76 22.2
0.67 22.3
0.61 34.1
0.46 37.3
0.54 35.6
1974 Certification Values
(1974 Audi Fox, 90 CID, 4-spd manual)
average values from two models tested
'75 .FTP*
2.15
28.0
1.55
22.5
*'74 models tested by '72 FTP.
in test procedure.
These results adjusted to reflect change
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Table II
Exhaust Emissions (grams per kilometre)
and Fuel Consumption (litres per 100 kilometre)
from a prototype Audi Fox
(Metric Units)
Procedure
HC
CO
NOx
Fuel Consumption
Urban Highway
•75 FTP
•75 FTP
Average
'77 Federal
Standards
'72 FTP hot start
'72 FTP hot start
'72 FTP hot start
Average
Highway Cycle
Highway Cycle
Average
0.093
0.086
0.090
0.255
0.054
0.046
0.061
0.054
0.040
0.033
0.037
0.59
0.59
0.59
2.11
0.22
0.24
0.25
0.24
0.33
0.33
0.33
0.51 10.7
0.58 10.8
0.55 10.8
1.24
0.43 10.5
0.35 10.6
0.47 10.6
0.42 10.6
0.61 6.9
0.46 6.3
0.53 6.6
•75 FTP*
1974 Certification Values
(1974 Audi Fox, 1475 cc, 4-spd Manual)
average values from two models tested
1.34
17.4
0.96
10.5
*'74 models tested by '75 FTP.
in test procedure.
These results adjusted to reflect change
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