71-14
     Exhaust Emissions From a Vehicle Equipped With the
Roberts Induction Modification Supplied Under Contract CPA 70-51
                       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 1970 Plymouth Duster equipped w~th a 225 cubic inch six
cylinder engine and automatic transmission was modified under
contract CPA 70-51. The modifications designed by Roberts
consisted of changes to the intake manifold, lean main jets
in the carburetor and revised camshaft. The ,intake modifica-
tion consisted of truncated cone inserts placed in each inlet
port.
Tests Conducted
The vehicle was tested as received from the
at two mileage increments. The vehicle was
the inserts removed from the intake system.
tests were run:
contractor and
also tested with
The following'
1. Standard 1970 Federal test procedure for exhaust
emissions (FTP).
2. Closed, constant volume sampling technique using
9 repeats of the 7-mode Federal emissions test cycle
(CVS) .
3. Closed, constant volume sampling technique using
the LA4-S3 driving schedule as specified for 1972 and
later testing (LA4).
Closed cycle data were taken using a constant volume sampling
technique. Bag samples from the CVS were analyzed usin~ non-
dispersive infrared analysis for carbon monoxide and the
Whittaker "NOx Box" for determination of oxides of nitrogen,
with hydrocarbons measured using a flame ionization detector.
NDIR was used for continuous NOx measurements in the FTP tests.
In addition to the standard emission tests, performance data
was obtained comparing this vehicle with a similar one from
our NAPCA fleet. The tests consisted of ~ide open throttle
accelerations from 0-60 mph, 20-50 mph and 40-80 mph.
Emission Results
The emission results in table 1 compare the average emissions
as received from the contractor and after removal of the in-
take manifold inserts. The data was taken using the 1972
Federal test procedure. Neither vehicle met the 1972 standards
although hydrocarbons were lower after the device was rer,~oved.
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In Table 2 comparisons between the as received vehicle and
after device removal on the 1970 test procedure shows that
the vehicle meets the standards after the device has been
removed, although there is a increase in oxides of nitrogen.
Table 3 reports all emission test results.
Performance Results
In Table 4 performance results are recorded showing very
similar acceleration times for the 20-50 mph and the 0-60
mph tests but faster acceleration for the standard yehiclE~
on the 50-80 mph acceleration.
Conclusions
1. The Roberts device caused no significant change in un--
burned hydrocarbons or carbon monoxide.
2. The Roberts device caused some (27%) reduction in oxides
of nitrogen.
3. The Roberts device had a small detrimental effect on
performance at high loads.

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TABLE 1
1972 Emission Test Procedure
  With 
  Roberts No
  Device Device
Hydrocarbons 3.9 3.4
Carbon Monoxide 43 43
  i 
Carbon Dioxide 45$ 422
  - 
  . 
Oxides of Nitrogen 2.7 3.7
All values taken by constant
reported in grams per mile.
are hydrocarbons 3.4 gpm and
gpm.
volume sampler and
Standards for 1972
carbon monoxide 39

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--."
TABLE 2
1970 Emission Test Procedure
  As No
  Received nevice
Hydrocarbons 2.4 1.8
Carbon Monoxide 23 19
Oxides of Nitrogen 3.7 4.2
i
All values taken in accordanc~ with the 1970
F~deral procedure and reported in: grams per mile.
Standards for 1970 vehicles are h~drocarbons 2.2
gpm and carbon monoxide 23 gpm. NOx measured by
NDIR and reported as N02.
"<'r

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1____-
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Mileage
Test
TABLE 3
HC
co
C02
with Roberts Device As Received, Test Summary
22198
9X7
FTP
CVS
22206
9X7
FTP
CVS
22218
LA4
22226
LA4
22725
9X7
FTP
CVS
22835
LA4
23101
LA4
23109
9X7
FTP
CVS
2.85
5.62
2.17
4.48
3.84
3.95
1. 92
3.52
3.48
12.47
2.61
4.73
24.51
44.53
452
20.96
22.76
42.49
459
44.43
451
18.29
30.6
398
46.4
522
51.0
501
22.91
45.3
437
All results reported i~ grams per mile
Device Removed, Test Summary
23151
9X7
FTP
23160
LA4
23142
LA4
1. 76
3.46
3.39
18.93
37.66
427
NOx
3.63
3.62
3.91
3.73'
2.70
2.69
3.71
4.31
4.06
3.67
4..07
5..0
4.21
3.22
4.32
All results reported in grams per mile.
~ean jets and modified comshaft.

9X7 indicates that the CVS and FTP tests were run concurrently.
48.86
418
Vehicle equipped with

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20-50 mph
.0-60 mph
50-80 mph
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TABLE 4
Performance Test Results
Roberts Vehicle
8.3 sec.
14.6
sec.
17.6 sec.
~
Standard Vehicle
8.4 sec.
14.5
sec.
16.4 sec.
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