Exhaust Emissions From a Passenger Car Equipped With the "Wilford Smog Suppressor"


Exhaust Emissions from a Passenger Car Equipped with the
               "Wilforct Smog Suppressor"
                      October 1970
                   Leonard D.  Verrelli
    Division  of Motor Vehicle  Research and Development
      National Air Pollution Control Administration
       Department of Health, Education-and-Welfare  -

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                                                       71-9
Exhaust Emissions from a Passenger Car Equipped with the
               "Wilford Smog Suppressor"
                      October 1970
                  Leonard D. Verrelli
   Division of Motor Vehicle Research and Development
     National Air Pollution Control Administration
      Department of Health, Education and Welfare

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Device Tested

The design characteristics of the Wilford Smog Suppressor
provided an opportunity to evaluate the effects of applying
back pressure to the exhaust system and ita relationship to
reduced emissions.  The testing was required as part of an
evaluation of retro-fit devices to aid in reducing emissions
in used vehicles.

The Wilford Smog Suppressor consists of a spring (calibrated)
controlled flapper valve that varies the back pressure depend^
ing on engine rpm.  It is clamped to the end of the exhaust
pipe with the valve opening downward.

The device was mounted on a 1963 Ford Galaxie test bed, with
a 289 cubic inch engine and automatic transmission.  There
is extensive emissions background data available on this ve-
hicle as a result of previous testing that would denote any
improvements made by the device.

Test Procedure

The device was tested under the 1970 Federal test procedure
as stated in the Federal Register, Volume 33, Number 108,
Part II, dated June 4, 1968, Subpart H, para. 85.7 b.

Emission Results

The data shown in Table I compare tests run both with and
without the Wilford Smog Suppressor.

Because of the increase of unburned hydrocarbons during
the cold cycle and the lack of any meaningful reduction in
both CO and NO it appears that the Wilford Smog Suppressor
has no beneficial effect on emissions.

Conclusions

The "Wilford Smog Suppressor" does not improve exhaust emis-
sion rates when evaluated using the 1970 Federal test proce-
dure.

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                   Table I


              1963 Ford Galaxie
   1970 Federal          HC       CO        NO
  Test Procedure         GPM      GPM       GPM

Without device          4.01     53.85     1.62

With Wilford Smog
  Suppressor            6.8?     50.16     1.83

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