71-13
A Report on the Exhaust Emissions of an Army M-151
      1/4 Ton Truck Using an Exhaust Catalyst
                  December 1970
                 John C. Thomson
Division of Motor Vehicle Research and Development
  National Air Pollution Control Administration
         ENVIRONMENTAL PROTECTION AGENCY

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Vehicle Tested

A standard Army 1/4 ton M-151 vehicle was tested for exhaust
emissions before and after installation of an Englehart Model
PTX catalytic exhaust reactor.  This vehicle uses a 141 cubic
inch, inline, four cylinder engine and requires an inertia
weight of 3000 pounds.  For these tests the reactor was in-
stalled in place of the standard muffler with an auxiliary
air line provided to supply air for the reactor.  The air was
supplied by a shop air system and flow was maintained at 2
cubic feet per minute.

Tests Conducted

  Baseline Tests

  The vehicle was tested prior to installation of the
  reactor and with the reactor installed as follows:

    1.  The 1972 Federal test procedure using the LA4-S3
    driving cycle (LA4).

    2.  Standard 1970 Federal test procedure for exhaust
    emissions (FTP).

    3.  Closed, constant volume sampling technique
    using 9 repeats of the 7-mode Federal emissions test
    cycle (CVS).

  Closed cycle data were taken as proscribed in the 1972
  Federal procedure for both the LA4 and the CVS tests.
  The Whittaker "NOx Box", an electro-chemical device, was
  used for determination of oxides of nitrogen in the CVS
  sample, and non-dispersive infrared was used during the
  FTP.

Emission Results

Table 1 shows a comparison between the vehicle as received
and as equipped with an exhaust reactor using the 1972 Federal
procedure.  This shows an increase in carbon monoxide with
reduction in hydrocarbon and oxides of nitrogen.  A complete
listing of all tests is shown in table 2.  The greatest reduc-
tion  in emissions between standard and the reactor is shown
on the 1970 Federal test  (FTP).  One reason for this effect
is due to the emphasis on the hot portion of the FTP where
the reactor is at its best.

All tests results are shown in grams per mile.

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                          -2-

Conclusions

lo  There is a slight (22%) improvement in unburned hydrocarbons
with the reactor«

2.  Carbon monoxide increased slightly  (15%) with the reactor,

3o  Oxides of nitrogen are moderately reduced  (41%) with the
reactor.

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                     TABLE 1

           1972 Federal Test Procedure


                               As
                            Received       Reactor
                                  ^

Hydrocarbons                  6.6           5.2

Carbon Monoxide                65 /           75

Oxides of Nitrogen            3.9 '          2.3


    All Results are Reported in Grams Per Mile.

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                         TABLE 2




        M-151 Test Data October and November 1970
Mileage
Test
HC
CO
C02
NOx
14997
15005
15024
15031
15043
15051
LA4
9X7
LA4
LA4
Rich
9X7
LA4
Baseline
6.4
FTP 6 . 4
CVS 9 . 8
5.2
7.3
76
32
68
51
68
481
395
539
495
3.4
2.0
2.3
4.5
3.8
Adjustment of Carburetor
FTP 4.9
CVS 7 . 9
7.7
Reactor - 2 SCFM Aux.
15064
15071
15078
15087
9X7
9X7
LA 4
LA4
FTP 1 . 5
CVS 3 . 1
FTP 1 . 6
CVS 4 . 1
4.8
5.6
74
86
111
Air
39
65
33
64
85
66
379
386
477
488
541
489
2.1
3.2
3.4
1.2
1.9
1.6
2.2
2.7
1.9
          All Results Reported in Grams Per mile

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