United States Air and Radiation EPA420-R-98-013
Environmental Protection October 1998
Agency
v/EPA Emissions and Fuel
Economy Effects of
Vehicle Exhaust
Emission Control Device
1 Printed on Recycled Paper
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EPA420-R-98-013
October 1998
Vehicle Programs Group
Vehicle Programs and Compliance Division
Office of Mobile Sources
U.S. Environmental Protection Agency
NOTICE
This technical report does not necessarily represent final EPA decisions or positions. It is
intended to present technical analysis of issues using data which are currently available.
The purpose in the release of such reports is to facilitate the exchange of technical
information and to inform the public of technical developments which may form the basis
for a final EPA decision, position, or regulatory action.
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1.0 Abstract
This report describes testing by EPA of the Vehicle Exhaust
Emission Control Device (VEECD) retrofit device under Section
32918 of Title 49 U.S.C. Retrofit Devices (RD). This testing was
conducted at the National Vehicle and Fuel Emissions Laboratory
(NVFEL) in Ann Arbor, Michigan at the request of the device
developer, Hawtal Whiting Environmental Ltd. of the UK. Since
submission of the RD application, Hawtal Whiting has established
a tradename, EVEC™ for the VEECD.
The VEECD is described by the developer in the international
patent application as an embodiment of air bleed principle. It
is intended to be retrofitted to vehicles produced without any,
or with earlier-technology emission control systems. It is not
compatible with newer complex engine management systems or
vehicles equipped with closed-loop three-way catalytic systems.
The device is designed to be inserted into the hose connecting
the inlet manifold to the vacuum brake booster and, as claimed by
the developer, acts to optimize the air/fuel mixture during idle
and deceleration.
The developer claims (RD Application Appendix A) that the
valve significantly reduces CO and HC emissions without
substantially increasing C02 or NOx emissions. Incidental city
fuel economy enhancement was also claimed. Non-FTP test data
obtained for 1986/87 European vehicles from two laboratories in
the UK was submitted. This data (Appendix B) was analyzed using
the t-test for the difference of constant speed data 30/60/85MPH)
at 95% confidence level and the following was concluded:
• The device appeared to reduce CO emission at low speed;
however, this effect is reduced at higher constant speed.
• HC and NOx emissions did not appear to be affected by the
device.
• The device seemed to have negligible effect on C02 emissions
and fuel economy.
The apparent CO emission reduction warranted EPA to proceed
with confirmatory testing of the VEECD device.
The developer provided two vehicles as basis for the test
program. Both were 1973 model-year light-duty vehicles. One was
a Dodge Dart powered by a 318 cubic inch engine; the other a Ford
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Mustang incorporating a base 302 cubic inch engine. Both
vehicles were selected by the developer because they appeared to
be close to original specification and incorporated the early-
technology emission-control systems with which the VEECD is most
compatible.
The agreed upon test plan sequence (Appendix C) included a
comprehensive inspection and maintenance identical to that
performed on in-use vehicles in EPA's Recall Program done by
Vehicle Programs and Compliance Division (VPCD). Federal Test
Procedures (FTP) were performed to establish the baseline
tailpipe emission output of both vehicles. The VEECD was then
installed on each vehicle by the developer's representative under
the auspices of EPA personnel in accordance with the written
instructions provided by the developer. The vehicles were again
subjected to FTP testing. The third and final test consisted of
a second baseline test without the VEECD.
Complete test data were collected only on the Ford because
an undiagnosed engine failure in the Dodge prevented this vehicle
from completing the second baseline test.
EPA concludes the following from the testing conducted
on these two vehicles:
• Use of the VEECD resulted in a decrease in hydrocarbon (HC)
and carbon monoxide (CO) emissions and an increase of oxides
of nitrogen (NOx) and carbon dioxide (C02) emissions in both
cars.
• Use of the VEECD resulted in an increase in city fuel
economy in the Ford. Fuel economy in the Dodge remained the
same.
2.0 Background
Under Section 32918 of Title 49 U.S.C., EPA is required, in
response to requests from certain sources, to evaluate
aftermarket retrofit devices and fuel additives (collectively
referred to as devices) that are claimed to improve fuel economy
and emissions. EPA receives information about many of these
devices that are represented by the device developer/manufacturer
as offering a potential for reductions in emissions and/or an
improvement in the fuel economy of conventional automobiles.
EPA's VPCD is interested in evaluating such devices because of
the obvious benefits the test results and analyses have for the
nation. EPA invites developers of devices to submit information
on the principle of operation together with available preliminary
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emission test data. In those cases where the
developer's/manufacturer's application meets certain established
program criteria, and the device shows promise in preliminary
screening tests at an independent laboratory, confirmatory tests
may be run at EPA's NVFEL in Ann Arbor, Michigan at the expense
of the applicant. EPA is also required to evaluate devices at
the request of the Federal Trade Commission and may perform such
a device evaluation at the discretion of the EPA Administrator.
The conclusions drawn from EPA evaluation tests are
necessarily of limited applicability. An all encompassing
evaluation of the effectiveness of a device in achieving
performance improvements on the many types of vehicles that are
in actual use would require a large sample of test vehicles.
This is not economically feasible in the evaluation projects
conducted by EPA. Therefore, the conclusions from such device
evaluation tests can be considered to be quantitatively valid
only for the specific test cars used; however, it is reasonable
to extrapolate the results from EPA tests to other types of
vehicles in a directional manner; i.e., to suggest that similar
results are likely to be achieved on other similar types of
vehicles.
3.0 Introduction
This report describes EPA's testing of the VEECD air-bleed
device under Section 32918 U.S.C. Title 49. The evaluation was
conducted to address claims of reduced emissions and incidental
improved city fuel economy performance of this device.
4.0 Purpose of the Test Program
The purpose of the EPA RD test program was to conduct a
controlled technical evaluation of the VEECD air-bleed device in
a manner that would address the developer's specific claims for
significant reduction in HC and CO; with incidental reductions in
fuel consumption during urban test cycles. Effect of the VEECD
on power, octane requirement, cleanliness of the combustion
chamber, and driveability were not evaluated. The developer made
the following statements with regard to the device:
Purpose:
A mechanical device, which can be easily retrofitted to old
vehicles to significantly reduce CO and HC emissions without
significantly increasing C02 and NOx emissions. Incidental
reduction in fuel consumption, particularly during the urban
cycle is also achieved.
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Applicability:
Effective on four-stroke spark ignition engines and
operates with carburetor and fuel-injection systems. VEECD
is not compatible with diesel engines.
Not compatible with complex engine management systems or
vehicles fitted with three-way, closed loop catalytic
converters. Weather and driving conditions do not adversely
affect the functionality of the VEECD.
Theory of Operation:
The VEECD enhances the efficiency of the mix between air/
fuel ratio in the combustion chamber and it also reduces
overall friction in the non-combustion cylinders.
Construction and Operation:
VEECD is a simple mechanical "T" shaped valve. It is fitted
to the vacuum brake servo line and acts to optimize the air/
fuel mixture during idle and deceleration.
Specific Claims;
Significantly reduces CO and HC levels. Incidental
reductions in fuel consumption, particularly in the urban
cycles have been achieved.
5.0 Test Plan
The test plan developed by EPA and approved by the developer
was as follows:
• The developer provided two test vehicles. Both were 1973
model-year light-duty vehicles. One was a Dodge Dart, the
other a Ford Mustang.
• Both vehicles were subjected to inspection and maintenance
identical to that performed on more recent model vehicles
selected for testing in the VPCD Recall Program. Both were
tuned as close to manufacturer's specifications as possible
given their age and engine wear, replacing parts as
necessary. The resultant air fuel ratio (AFR) was rich of
stoichiometry in both vehicles.
• Baseline FTP testing was performed to establish the
emissions and fuel economy of both vehicles prior to the
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installation of the VEECD. The FTP (Federal Register; 40
CFR Part 86; July 1, 1990) is the official EPA test
procedure for determining the exhaust emissions and city
fuel economy of a vehicle. The vehicles were not tested for
evaporat ive emi s s ions.
• A VEECD was installed in each vehicle and adjusted per
developer's procedure by a developer's representative under
the auspices of EPA personnel. No adjustments were made to
any engine components between tests.
A second set of tests was then performed to evaluate the
performance of the VEECD.
The device was removed prior to the second series of
baseline tests. Again, no adjustments were made to any engine
components between tests. Only the Ford completed this phase of
testing. Due to an undiagnosed engine failure, the Dodge did not
complete its second baseline test.
Claims other than improved city fuel economy and reduced CO
and HC exhaust emissions were not specifically addressed. These
other claims are in large part subjective, and procedures for
their evaluation are neither well defined nor routinely used by
EPA. In addition, to evaluate other claims or vehicle system
effects would require extensive vehicle mileage or engine out-of-
vehicle operation. It should be noted however, that test
technicians noted no driveability problems during the test
driving cycles.
The device developer representative was present for all
test phases except the first series of baseline tests.
6.0 Results
The results of EPA testing can be found in Table 1. These
data have been analyzed and indicate the following:
• Neither vehicle met all emission standards for which they
were originally designed even though both had been tuned as
close to the manufacturer's specifications as possible and
certain parts replaced as necessary. The resultant air fuel
ratio for both the Dodge and Ford was rich of stoichiometry
at 14.4 and 13.6 respectively. Given the age and engine
wear of the vehicle, this is not unusual.
• HC and CO decreased from each vehicle with installation of
the VEECD.
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• HC and CO were decreased by 21% and 31% respectively in the
Dodge; 4% and 20% in the Ford.
• NOx emissions increased from both cars with the installation
of the VEECD; 13% for the Dodge and 10% for the Ford.
• C02 emissions from both cars increased also; 6% for the
Dodge, 4% for the Ford.
• No improvement in city fuel economy was seen in the Dodge;
however, city fuel economy did improve by 2% in the Ford.
7.0 Conclusions
EPA concludes the following from the testing reported above
(See Table 1).
EPA testing confirmed the trend of data and claims submitted
by the developer. The VEECD showed a decrease in HC and CO
emissions from two examples of vehicles incorporating older
emission control system technology. Volumes of such vehicles are
small in the United States so applicability of the VEECD
domestically would be quite limited. However, other geographic
locations where there are high volumes of vehicles with older
emission control systems might benefit from VEECD usage in
reducing CO and HC's provided that any NOX increase does not lead
to increase in ozone (03) levels. Ozone is formed in ambient air
from photochemical reactions of HC's and NOX. A recent report1
emphasizes the increased importance of NOX in 03 formation. The
relative importance of HC and NOX control varies from one part of
a geographic location to another depending on local conditions.
EPA regulates vehicle emissions of CO to meet ambient CO levels
and HC and NOX to meet acceptable 03 levels. Therefore, based
upon this very limited amount of test data from one vehicle that
completed the test plan, it would seem that the use of VEECD on
vehicles containing older technology emission control systems may
be environmentally beneficial because of the reduction in HC and
CO for areas meeting HC and CO controls. However, any NOX
increase must be considered since in some conditions NOX
emissions are more important than HC in ozone formation.
Finally, the fuel economy increase seen in the Ford was not
significant for a test sample of this size.
•"•"Rethinking the Ozone Problem in Urban and Regional Air
Pollution", National Research Council, 1992, National Academy
Press, 2101 Constitution Ave., NW, Washington, DC 20418.
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