Report on the Exhaust Emissions of an Army M-151 1/4 Ton Truck Using an Exhaust Catalyst


                                                   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-15l 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 wa.s
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 ~4 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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Conclusions         :

1.  There is a slight (22%) improvement in unburned hydrocarbons
with the reactor.

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

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

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TABLE 1
1972 Federal Test Procedure
  As 
  Recei ved 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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I  TABLE. 2     
 M-151 Test Data October and November 1970 
Mileage Test    HC CO C02 NOx
  B.ase1ine    
14997 LA4    6.4 76 481 3.4
15005 9X7 FTP 6.4 32  2.0
  CVS 9.8 68 395 2.3
15024 LA4    5.2 51 539 4.5
15031 LA4    7.3 68 495 3.8
 Rich Adjustment of Carburetor  
15043 9X7 FTP 4.9 74  2.1
  CVS 7.9 86 379 3.2
15051 LA4    7.7 III 386 3.4
 Reactor - 2 SCFM Aux. Air  
15064 9X7 FTP 1.5 39  1.2
  CVS 3.1 65 477 1.9
15071 9X7 FTP 1.6 33  1.6
  CVS 4.1 64 488 2.2
15078 LA4    4.8 85 541 2.7
15087 LA4    5.6 66 489 1.9
 All Results Reported in Grams Per mile 
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