Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA 420-R-98-013

October 1998

Emissions and Fuel

Economy Effects of

Vehicle Exhaust

Emission Control Device
Emissions and Fuel Economy Effects of Vehicle

Exhaust Emission Control Device

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.

EPA420-R-98-013

October 1998
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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, EVECTM 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 CO2 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 CO2 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 earlytechnology 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 (CO2) 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 CO2 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

evaporative emissions.

& 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-ofvehicle 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.
1

"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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& 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.

& CO2 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 (O3) 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 O3 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 O3 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.