73-1
Evaluation of Vor-Air Device,
    A Retrofit EGR System
        August 1972
       Henry L. Gompf
Control Device Evaluation Section
 Environmental Prptectipn Agency

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Background

      Vor-Air Inc. of Las Vegas, Nevada, contacted the Office
of Air Programs and requested an evaluation of an exhaust gas
recirculation retrofit device currently under development.
Data was presented from Scott Laboratories, Inc. of San
Bernardino, California, compiled using a 1969 Ford Mustang.
The results of this testing indicated a 23% reduction in carbon
monoxide and a 38% reduction in oxides of nitrogen.  The change
in hydrocarbon level was negligible.  An evaluation of the
Vof-Air system was initiated by the Test and Evaluation  Branch.

Device Description

      The Vor-Air system tested was basically a simple exhaust
gas recirculation device with the addition of an air-bleed system.
Exhaust was picked up from the exhaust manifold and piped
through a control valve to the PCV line for introduction into
the intake manifold.  In addition filtered air from the air
cleaner housing was allowed to mix with the EGR flow into the
PCV line.

      EGR flow was allowed at idle and'increased with decreasing
manifold vacuum.  No measure of the absolute EGR or bleed air
rates have yet been made.  Two different orifice plates were
tested in the control valve to optimize the relative carbon
monoxide-oxides of nitrogen control, by altering the amount of
EGR flow and hence filtered air-flow rate.

      The system requires about 45 minutes to install.  Total
installed cost to the consumer would probably be less than
thirty-five dollars.

Test Program

      Baseline and device tests were performed using a 1970
Plymouth Valiant equipped with an automatic transmission and
225 CID six-cylinder engine.  All testing was conducted in
accordance with the 1972 Federal emission test procedure as
described in the November 10, 1970, Federal Register.

Test Results

      The results of baseline and device testing (small and large
orifice in the control valve) are presented in the Appendix
of the report.  These results can be summarized as follows:

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              Percent Reduction from Baseline
HG
2%
-6%*
CO
11%
3%
C07
5%
4%
NOx
46%
42%
Large Orifice

Small Orifice

*increase

      In addition to substantial reduction in the oxides of
nitrogen level, the data indicates a potential fuel economy
benefit with the system installed.  Changes in hydrocarbon and
carbon monoxide levels were not significantly different from
usual test variability.

Conclusions

1.  Vor-Air demonstrated significant control of oxides of
nitrogen during the EPA evaluation.

2.  No adverse effect on hydrocarbon or carbon monoxide levels
was detected.

3.  Optimization of EGR vs. bleed air flow rates might lead to
better overall emission control.

4.  Durability and driveability effects of the system should
 e quantified to better assess the full potential and applicability
 f the system.

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           Vor-Air 1972 FTP Emission Results
            (all results in grams per mile)
          Average

Vor-Air
Large Orifice
7/25/72
7/27/72
          Average
Percent Reduction

Vor-Air
Small Orifice
7/31/72
8/01/72
          Average
Percent Reduction
HC
2.66

2.18
2.42
2.44
2.29
2.37
2%
2.71
2.40
2.56
-6%*
CO
41.54

35.33
38.44
34.04
34.40
34.22
11%
40.10
34.81
37.46
3%
C02
440.09
t
444.85
442.47
439.39
40.520
422.30
5%
414.06
439.71
426.89
4%
NOx
5.53

5.46
5.50
3.01
2.88
2.95
46%
3.08
3.30
3.19
42%
*i
 increase

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