&EPA
United States
Environmental Protection
Agency
Region H Office
26 Federal Plaza
New York, N.Y. 10007
EPA 902/4-81-001 a
May 1981
Air
STUDY OF CONTROL STRATEGIES FOR IN-USE HEAVY
DUTY VEHICLES
FINAL REPORT
-------
STUDY OF CONTROL STRATEGIES FOR IN-USE HEAVY DUTY VEHICLES
Final Report
Environmental Protection Agency Contract Number 68-01-4319
Submitted to Project Officer
William S. Baker
Chief, Air Program Branch
Region II
U.S. Environmental Protection Agency
Submitted by
John J. Pinto
Assistant Director, Mobile Systems
NYC Department of Environmental Protection
Bureau of Science & Technology
-------
This report was furnished to the Environmental Protection
Agency by the N.Y.City Department of Environmental Protection,
Mobile Systems Division, Brooklyn,New York in fulfillment of
EPA Contract No. 68-01-4319. This report has been reviewed by
Region II, EPA and approved for publication. Approval does not-..
signify that the contents necessarily, reflect the views and
policies of the Environmental Protection Agency, nor does mention
of trade names or commercial products consitutute endorsement
or recommendation for use.'
Region II publication No. 902/4-81-001 a
-------
ADDENDUM
This ADDENDUM attempts to resolve ambiguities and
omissions in the text that have been pointed out by re-
viewers.
1. On page 1 and again on page 19 it is stated that
Nox results are not significant at the 95% confidence
level, but no mention is made of the statistical
criteria for the CO, HC and fuel economy results.
It should be understood that these were also tested
at the 95% level.
2. Apparent contradictions appear in the tables that
show the average of the measured pollutant levels
before and after tune up and also the average of
the percent change in pollutant levels. One example
of these contradictions.appears in Table IV-D-1
for the CO levels measured in C39 tests. The first
line shows that CO emissions averaged 262.90 g/mi
before tune up and the second lines shows that tune
up reduced the average to 245.96 g/mi, a reduction
of about 7%. Yet the third line, which gives the
percentage change in emissions per vehicle, averaged
over all vehicles, shows an average increase of 15%
in emission level.
The reason for this apparent contradiction is the
occurance of vehicles with unusually low emission for
the pollutant and for which the emission increased after
tune up. Since the emission is small this vehicle has
a proportionally small influence on the ration of the
averages before and after tune up as found from rows one
and two. However, because its emission is small the per-
centage increase in emission can be large for that vehicle.
One or more vehicles with these characteristice can out-
weigh the percentage reduction in emission from the other
vehicles when averaged to find row three.
It is^interesting to compare the uses of the percent
reduction in emission that is found from the ration of
row one and row two with the percentage change per vehicle
given in row three. An air pollution control engineer
concerned with evaluating results 'of an I/M program would
be interested in the changes in average emissions found
from rows one and two. An engineer concerned with setting
up and instrumenting program would be concerned with being
able to measure the increases in emissions that sometimes
occur after tune up as shown in row three.
-------
3. On page 20 it is noted that the dynamometer could
not test the heaviest vehicles under full load. It
has been suggested that a correction factor be used
to compensate for the effect of underload on emissions
from the heaviest vehicles. Such a factor might be
calculated, for example, by making a linear regression
analysis of the test data to determine how emissions
vary with vehicle weight. However, it is unlikely
that the results of such analyses would be reliable
enough to justify the effort.
4. A question was raised about the possible cost of an
EGR retrofit device. The report did not provide a
cost estimate because such devices are no longer being
manufactured and it is difficult to extrapolate the
cost of a retrofit EGR device from the cost of original
equipment EGR systems. However, when retrofit kits
were available they were priced at under $35. Allowing
for inflation and changes in technology it is probable
that, if the market was created, manufacturers of o.e.
EGR systems would offer retrofit kits in the $60 to
$90 price range.
5. It was suggested that it would be helpful to summarize
the results of EGR retrofit tests in a table similar
to Table IV-J that summarizes results on ADAKS air
bleed devices. As explained in the report, by the
time the study was ready to start extensive testing
of EGR retrofits they were no longer being manufactured.
Insufficient EGR retrofit test data were taken to
warrent preparation of a table similar to Table IV-J.
6. It was pointed out that in Table IV-J, Figures 4-A thru
4-J and the graphs of APPENDIX II no indication is given
of the procedure used to find the results. Unless other-
wise stated all the results were obtained from New York
Quick cycle tests.
7. Typographical errors were pointed out in Table IV-I.
The Description line for the Air Jet/Ball-Matic device
should read "Air bleed to PCV line, spark advance"and
the correct description for the A.Q.P. Pure Power device
should read "Capacitor discharge ignition system".
-------
ABSTRACT
To collect baseline information for heavy duty vehicle
Inspection/Maintenance programs, a large fleet of in-service
gasoline powered vehicles were chassis dynometer tested for
HC, CO and NOx emissions and fuel economy in as-received
condition and again after being tuned to their manufacturers'
specifications. Computer analysis of the changes produced
by tuning are presented and discussed.
To investigate the suitability of commercially available
non-catalytic emissions control devices for heavy-duty-vehicle
retrofit programs over fifteen such devices were screened.
Exhaust gas recirculation devices/ air bleeds and lean mixture
carburetors were selected as promising candidates for retrofitting.
These devices were installed on in-service heavy duty vehicles."
Emissions and fuel economy were tested immediately after install-
ation. The vehicles were recalled and retested periodically to
monitor changes in devices effectiveness with use and time.
Test results are evaluated to determine the applicability of
the devices to a heavy duty retrofit program.
-------
II
TABLE OF CONTENTS
Paqe
Abstract ......... I
Table of Contents. ....... II
List of Tables ........ Ill
List of Figures ........ IV
Summary . ........ 1
I. Goals of the Study ....... 3
Retrofit ....... 3
Inspection/Maintenance. ..... 4
II. The Tests ........ 5
A. The Test Plan ....... 5
B. Instrumentation ...... 10
III. Vehicles and Fleets ...... 11
IV. Results . . . . . . . .18
A. Results of the Inspection/Maintenance Study 18
B. Results of the Retrofit Study ... 23
1. Screening ...... 23
2. Exhaust Gas Recirculation Devices . 28
3. Air Bleeds ...... 30
4. Lean Mixture Carburetors ... 41
5. Description of Screened Devices . . 43
V. Conclusions ........ 46
A. Conclusions from the Inspection/Maintenance
Study 46
B. Conclusions from the Retrofit Study . . 46
1. Conclusions on EGR Devices . .47
2. Conclusions on Air Bleed Devices . . 48
3. Conclusions on Lean Mixture
Carburetors . . . . . .48
VI. References ........ 50
-------
Ill
LIST OF TABLES
Table
IV-A Distribution of I/M tests by fleet and vehicle weight
(2 Tables)
IV-B Statistics for all Inspection/Maintenance tests
IV-C Averages of New York Quick and C39 tests from Table IV-B
IV-D Statistics for Inspection/Maintenance tests grouped by
vehicle weight (3 Tables)
IV-E Means and standard deviations of emissions measurements
from a study by the Southwest Research Institute
IV-F Statistics for Inspection/Maintenance tests grouped by
model year (2 Tables)
IV-G Statistics for Inspection/Maintenance tests grouped by
vehicle weight and model year (6 Tables)
IV-H Statistics for Inspection/Maintenance tests grouped by
fleet (6 Tables)
IV-I Non-catalytic devices screened
IV-J Percent change in pollutant level and fuel economy produced
by ADAKS
IV-K Initial change in emissions upon installation of a lean
mixture carburetor
-------
IV
LIST OF FIGURES
Page
Fig.l The New York Quick driving cycle 6
Fig.2 The C39 driving cycle 7
Fig.3 The C39H driving cycle 8
Fig.4 Percent change in emissions and fuel
economy produced by ADAKS (10 Figures) 31
-------
-1-
SUMMARY
The present study is divided into two parts; one to
evaluate retrofit of heavy duty vehicles with non-catalytic
emissions control devices, the other to investigate heavy duty
inspection and maintenance by measuring the change in exhaust
levels of hydrocarbons, carbon monoxide, oxides of nitrogen and
in fuel economy after engines were tuned to manufacturer's
specifications.
To evaluate retrofit, over 15 commercially available devices
were screened to determine their potential for a heavy duty
vehicle retrofit program. Exhaust gas recirculation devices,
air bleeds and lean mixture carburetors were selected as promising
devices. Commercially available models of the three devices
were installed on in-service heavy duty vehicles. Emissions and
fuel economy were measured before and after retrofit by chassis
dynamometer tests.
After testing, the vehicles were returned to their owners
and were periodically recalled and retested. Where possible
retests were performed with the retrofit device operational and
also with the device detached in order to evaluate the reduction
in emissions produced by it.
A heavy duty retrofit program appears to require an obligatory
inspection/maintenance program. The Inspection/Maintenance study
was conducted to get baseline data for such a program. A large
sample of heavy duty gasoline powered vehicles from ten commercial,
municipal, state and federal fleets were tested.
Fuel economy and emissions from the vehicles were measured in
as-received condition by chassis dynamometer testing. The engines
were then tuned to manufacturers' specifications and the vehicles
were retested.
When after-tune-up tests were complete those vehicles that
were also part of the Retrofit study had a retrofit device installed,
Data recorded during the Inspection/Maintenance and Retrofit tests
and engine parameters recorded during tune up were keypunched and
entered on magnetic tape allowing electronic data processing to be
used for statistical analysis of the results.
Analysis of 181 pairs of before-and-after tune up tests from
the Inspection/Maintenance study shows that tune up resulted in
average reductions of about 36% in hydrocarbon emissions and 33%
in carbon monoxide emissions. There was no statistically signifi-
cant change in oxides of nitrogen emissions. Fuel economy increased
almost 4% which, at a fuel price of $1.30 a gallon, would represent
a savings of $8.80 for every 1,000 miles driven.
-------
-2-
Tests on the three retrofit devices showed them capable of
producing sizeable reductions in emissions. However, other studies
at this facility indicate the potential of catalytic converters
for a heavy duty retrofit program is superior to non-catalytic
devices.
The durability of the devices, when properly installed, was
good. Exhaust gas recirculation devices are more difficult to
install in heavy duty vehicles than in lighter vehicles. Unless
properly maintained they may cause drivability problems. These
factors weigh against their use in a heavy duty retrofit program.
Air bleeds and lean carburetors can make considerable improve-
ment in emissions from older vehicles. For newer vehicles most of
this improvement has already been realized by other means. The
devices could be considered as elements in a broader retrofit strategy,
A program for retrofitting with lean mixture carburetors would
have to be preceded by a study of how to select the carburetors
and how to adjust them to minimize emissions.
-------
-3-
I. GOALS OF THE STUDY
Controlling undesirable emissions of pollutants from
heavy duty (HD) vehicles by retrofitting them with control
devices was proposed in the New York City Metropolitan Area
Air Quality Implementation Plan in 1973.(1)* A study of
retrofit devices for HD vehicles was conducted under an
Environmental Protection Agency grant by the Bureau of
Motor Vehicle Pollution Control of the New York City Depart-
ment of Environmental Protection.(2)
In that investigation, which will be referred to as the
"Grant" study, existing control devices were screened to
determine their suitability for retrofit. Catalytic conver-
ters, air bleed devices, lean carburetors and exhaust gas
recirculation devices were chosen as promising and examples
of these controls were retrofitted on in-service vehicles
and tested.
The present study was devided into two parts; one to
evaluate retrofit, the other to investigate inspection and
maintenance (I/M).
RETROFIT
Existing non-catalytic control devices were screened to
determine their suitability for retrofit. Factors considered
included emissions reduction potential, cost, availability,
ease of installtion, effects of installation on vehicle opera-
tion and fuel economy and possible mechnaical and safety
problems.
Devices selected in the screening process were installed
on in-use vehicles and tested. The vehicles were periodically
retested to investigate durability and reliability of the
devices under in-service conditions.
The study is an extension of the earlier Grant study and
wherever possible incorporates the results of that study.
* References are in Section VI.
-------
-4-
Inspection/Maintenance
For a retrofit strategy to be effective in controlling
emissions an inspection/maintenance program will be required
to ascertain that the retrofit is properly installed and
that the device and the vehicle are properly maintained.
To provide baseline data for an I/M program a large group of
HD vehicles were gathered from ten municipal and privately
owned fleets. The vehicles were tested at the New York City
Emissions Control Laboratory in their "as received" condition
to obtain baseline data on hydrocarbon, carbon monoxide and
oxides of nitrogen emissions levels and fuel economy as well
as information on engine condition and general condition.
The vehicles were then tuned to manufacturers' specifications
and retested.
For the first time data were collected on a large group
of in-service gasoline powered HD vehicles that allow compar-
ison of emissions levels and fuel economy in the on-the-road
condition with levels in the tuned-to-specifications condition.
The data will help establish realistic criteria for I/M programs
-------
-5-
II. THE TESTS
II.A. THE TEST PLAN
All vehicles were inspected when first received and infor-
mation including the owner, chassis identification number,
owner's identification number, service type, make, model,
model year, and general condition were recorded on vehicle
I.D. forms.
Vehicles were then tested for the I/M study on a chassis
dynamometer in "as received" condition. Hie vehicles were
driven through a set of driving cycles referred to as the
New York Quick Cycle, the C39 cycle and the C39H cycle. The
vehicle was also driven through a standard Clayton (2) Keymode
cycle.
The N.Y. Quick cycle, developed in 1368 for the N.Y. State
Dept. of Health to represent N.Y. City driving conditions is
illustrated in Fig.l. The C39 cycle, developed to represent
HD vehicle driving conditions in N.Y. City traffic is shown in
Fig.2. Early in the study it was found tJat drivers were
having difficuty in following the C39 cycle and it was slightly
modified. The modified version, called C33H, is shown in Fig.3.
Aside from the length of the cycles the main difference between
the N.Y. Quick and the C39 cycles is the greater number of
accelerations and decelerations in the C39 cycle.
A typical set of I/M tests consisted of two independent
N.Y. Quick cycle tests, two independent C39 or C39H cycle tests
and one standard Keymode Test. Emissions of HC, CO and NOX and
fuel economy were measured and manually recorded on test-record
forms. Ambient atmospheric temperature, pressure and humidity
were also recorded.
When the as-received I/M test sets were complete the engine
of the vehicle was tuned. Engine parameters recorded before and
after tune up include idle r.p.m., timing and dwell angles, air/
fuel ratio, spark plug gap, idle HC and CO emissions measured by
inspection-station-type instrumentation, air filter and PCV valve
condition and general engine condiiton. Parts replaced, adjust-
ments and engine repairs, if any, were also recorded. Vehicles
were tuned by adjusting the engine parameters to manufacturer's
specifications. Where.the specification indicated a permissible
range for a parameter the value in the range that minimized CO
emissions levels without unduly increasing HC emissions was
selected.
-------
m
CL
z:
LJ
LJ
LJ1
Ld
_J
IE
u
N
V
[
l I
,
L> IR i
V
INEB
3
ui
.
IS
.
-
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ra
is
si
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:
IS
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IS
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Fig. 1 The New York Quick driving cycle
-------
HE1.IZ1IZI
01
TIME: CMINUTEISD
Fig. 2 The C39 driving cycle
-------
OR ! VINE
I
00
TIME: CMINUTEIBD
Fig. 3 The C39H driving cycle
-------
-9-
After tuning the vehicle was again tested on the dynamometer
and the "after-tune-up" test set results were recorded. For
identification, each test set was assigned a unique four digit
tests set number. Test set number were assigned in chronological
order. Test set results and engine parameters were coded, key
punched and recorded on magnetic computer tape.
After I/M tests were finished those vehicles that were
also part of the RETROFIT study were retrofitted with an
emissions control device installed and adjusted to manufacturers
specifications. An hour meter initially set to zero was also
installed to measure the number of engine operating hours from
retrofit. When necessary, minor adjustments to the engine
parameters were made according to the installation procedures
recommended by the control device manufacturer. After retrofit
vehicles were given a set of tests on the dynamometer.
A tune up is part of the manufacturer's recommended install-
ation procedure for all retrofit emissions control devices.
In the present study comparison of the before-tune-up- and after-
-tune-up I/M test sets show the emissions reduction and fuel
economy improvement resulting from the tune up alone. The after-*
tune-up I/M set represents a "baseline" for a properly tuned
engine. Comparison of this baseline and the after-retrofit set
allows evaluation of the improvement attributable to the device.
RETROFIT vehicles were retested at periodic intervals.
The vehicles were not tuned before retesting, but were tested
in "as received" condition. The only exceptions were vehicles
received so out-of-tune that they could not be retested without
tuning.
Where possible the vehicles were retested with the device
attached and also with the device detached or rendered inopera-
tive. This was done because emissions from the in-service
vehicles varied widely from retest to retest. However, comparison
of test sets taken with and without the device provided a measure
of the effectiveness of the device in controlling emissions.
-------
-10-
II.B. INSTRUMENTATION.
Tests were driven on a Clayton Dynamometer CT200
with direct drive inertia loading from 1,750 to 13,500 Ib.
Exhuast sampling used a Scott Constant Volume Sampler
302H set at positive-displacement-pump flow rates of 325
or 500 cubic feet per minute.
Exhaust hydrocarbons and carbon monoxide were measured
during tune up with garage grade instruments. Horiba GSM-300
and Sun EPA-75 non dispersive infrared analyzers were used.'
The Horiba was also used in Keymode tests.
The laboratory grade gas analyzers used with the CVS
system were:
Hydrocarbons - Scott 116 flame ionization detector.
Carbon monoxide - Beckman 865 NDIR.
Oxides of nitrogen - Scott1 125 Chemiluminescence.
-------
-11-
III. VEHICLES AND FLEETS
Obtaining a large group of heavy duty vehicles for
testing was a formidable job. Committing trucks to a test
program, even a few hours, represented an appreciable ex-
pense to commercial operators. To New York City municipal
fleets responsible for maintaining essential services with
limited resources the diversion of a vehicle for testing
was a serious consideration. A free tune up, the operators
reward for participating in the study was hardly enough
compensation for allowing a vehicle to be tested.
Possibly anticipated public relations benefits influenced
private fleet owners to participate in the study. City
commissioners and assistant commissioners exerted some influence
on municipal fleets to secure vehicles although their influence
was limited by the overwhelming priority of maintaining
public services. Ultimately the study had to rely on the
good will and public spirit of the fleet operators and
gratitude is due for their response.
Many problems were encountered. Even though these
vehicles were in service a number were received in too
poor condition for testing. Early in the study considerable
repair work was done on such vehicles to make testing
possible, but the time and cost of repairs soon made it
necessary to stop this practice.
Vehicles in the RETROFIT study were scheduled to
return periodically for retesting. Tests were freguently
delayed or cancelled by an emergency requirement for the
vehicle, because of drivers' srtikes, or a variety of
other reasons. Sometimes the control device was disconnected
or removed during emergency repair of a vehicle.
Over 178 vehicles were supplied by ten commercial,
municipal and other fleets. The fleets and vehicles are
identified in the following list.
Several vehicles involved in the study are not listed.
These include vehicles received in too poor condition for
testing, trucks withdrawn from the study by their owners
and vehicles used in screening tests on devices that were
considered not worth including in this report.
-------
VEHICLES TESTED FQH U.S. ENVIRONMENTAL PROTECTION AGENCY CONTRACT 68-01-^319.
PAGE
BROOKLYN UNION QAS CO. *****
OWNER ' S
!U NUMBER
31?.3
4071
4202
4251
4274
4308B
4419
4595
4662
4706
4780
61 19
6583
6719
S851
OWNER'S
ID NUMBER
4 172
4306
5162
5210
5302 .
5344
5355
5419
5470
5522
5613
5724
5927
6201
6303
6325
6349
63 62
GROSS
W EIGHT
10000
10000
21 000
24000
21 000
21 000
21 000
-3 I 200
21 000
17000
2VOOO
34000
2', 000
21000
24000
GROSS
WEIGHT
10000
1 COCO
19500
14000
19500
14000
14000
32500
2 I 200
asooo
19500
19500
17000
34000
24000
24000
26000
26000
MODEL
YEAR
1073
1971
1970
1971
1971
1970
1969
1975
1971
1973
1968
1971
1963
1966
1968
MODEL
YEAR
1968
1973
1967
1970
1969
1974
1969
1970
1973
1971
1962
1969
1976
1971
1963
1969
1969
1969
ENGINE
DISPLACEMENT
350
250
330
318
330
330
330
330
330
330
330
400
292
330
391
ENGINE
DISPLACEMENT
292
292
292
292
292
350
292
351
345
361
261
292
330
413
351
366
400
400
XM I SSI ON
CODE
M4
M4
W5
M5
M4
M5
M5
M".
MS
M5
M5
T.15
M5
M5
Ma
4 * * * *
XMISSION
CODE
M4
M4
A6
M4
A6
M4
M4
A6
A-1
A4
M')
A6
A4
AC
AG
A 6
A6
A6
MAKE
GWC
CHEVROLET
FORD
DODGE
FOF^O
FORD
FORD
FORD
FORD
FORD
FORD
WHITE
FORD
FORD
FORD
CONSOLIDATED
MAKE
GMC
GMC
CHEVROLET
GMC
CHEVROLET
GMC
GMC
GMC
I-H
FORD
FORD
CHEVROLET
FORD
DODGE
GMC
CHEVROLET
WHITE
WHITE
MODEL
3500
30
C600
0500
C600
C600
C600
C600
C600
F500
C600
2300
C600
C600
C750
NUMBER OF VEHICLES
EDISON CO. *****
MODEL
3500
3500
50
3500
50
3500
3500
6500
1 610A
F700
C600
C50
C600
M800
7500
60
3200H
3200H
15
I
H
NJ
-------
VEHICLES TESTED FOR U.S. LNVIRO'.ULNTAL PROTECTION AGENCY CONTRACT 68-01-4319.
PAGE 2
6399
6513
6910
OvJNER' S
ID NUMBER
T49
117009
OvJNER ' S
10 NUMBER
09A018
25D?.".7
25D032
25D085
250092
25D1 16
25D1 41
25D201
25(3318
25D369
250384
25E020
25E021
25E1 46
25E150
25E155
?5E155
2rC157
2bE1 59
25E160
25E161
25E1 63
25E164
25E165
?SE1 65
25E168
25E169
?5500
21 000
22000
GROSS.
WEIGHT
10000
07500
GROSS
WEIGHT
44000
37300
37300
37800
37300
37800
37300
37800
37800
37800
37800
37800
37800
37800
37800
37800
37000
37800
37800
37800
37800
37800
37800
37000
37800
37800
37800
1971
1973
1961
MODEL
YEAR
1969
1969
MODEL
YEAR
1973
1970
1970
1970
1970
1 970
1970
1970
1970
1 970
1970
1972
1972
1972
1972
1972
1972
1972
1972
1972
1972
1S72
1972
1972
1972
1972
1972
361
366
318
"
ENGINE
DISPLACEMENT
307
307
*
ENGINE
DISPLACEMENT
501
478
4J8
478
478
478
478
478
478
478
478
478
476
47?
479
478
478
478
478
478
478
478
478
478
478
478
478
P.I 5
A 'I
M4
**+* MEW YORK
XM I SSI ON
CO DC
A3
A3
*++* NEW YORK
XMISSION
CODE
A4
A 6
AG
A6
A6
AG
A6
AG
A6
AG
AG
A 6
AG
A 6
AG
AG
AG
AG
AG
A13
AG
AG
A 6
AG
AG
AG
A6
FORD
GMC
DODGE
CITY DEP r .
MAKE
CHEVROLET
CHEVROLET
CITY DEPT.
MAKE
I-H
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
GMC
CMC
GMC
GMC
GMC
GMC
GMC
GMC
F700
6500
D600
NUMBER OF VEHICLES 2
OF AIR RESOURCES *****
MODEL
P30
CE20
NUMBER OF VEHICLES
OF SANITATION *****
MODEL
1910A
8500
8500
8500
8500
8500
8500
6500
85CO
8500
8500
8500
8500
P500
8500
8500
3500
8500
8500
8500
8500
P500
8500
8500
G500
8500
6500
00
I
-------
25E1 70
25E171
2SE1 77
25E182
25E183
25G055
25G059
25G080
25GOR9
25G090
25G091
25G184
25G190
25G192
25G193
25H173
2GB01 2
20D008
200024
2GD055
2GD066
267016
OWNER1 S
ID NUMBER
1 12004
125001
125002
125003
125005
137002
137004
145001
145004
145005
147001
147002
100003
175001
176001
1 7G002
1 7B002
182001
37800
37600
37600
37800
37800
40000
4COOO
40000
40000
40000
40000
40000
40000
40000
40000
40000
37800
40000
40000
40000
40000
39850
G
AG
A6
A6
A6
AG
AG
A 6
A6
AG
AG
A 6
A6
A-)
A6
A6
A6
AS
AS
AG
*** NflA! YORK
XM I SSI ON
CODE
M5
M-1
M'l
M4
M-l
M4
M.I
M4
M4
M4
M<1
M4
M4
M.I
!M
W4
M4
M5
GMC
GMC
GMC
GMC
GMC
I-H
I-H
I-H
'I-H
I-H
I-H
I-H
I-H
I-H
I-H
I-H
GMC
GMC
GMC
GMC
GMC
GMC
CITY DEPT.
MAKE
I-H
DODGE
DODGE
DODGE
DODGE
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
FORD
8500
8500
8500
8500
8500
20 1 OA
20 1 OA
20 1 OA
20 1 OA
20 10A
20 iOA
20 1 OA
20 10A
20 10A
20 1 OA
8500
8500
8500
8500
esoo
B500
NUMBER OF VEHICLES 49
OF WATER RESOURCES *****
MODEL
1 910A
D500
D500
D500
D500
F350
F350
F600
F600
F600
P600
F600
FGOO
F6CO
FGOO
F600
F600
C800
68-01-4319.
PAGE 3
-------
221002
279001
2E2003
2B2019
282C20
282021
282022
290003
290009
290010
29001 1
290012
2°0013
290014
290015
290016
290017
290018
293004
2970C1
297002
323001
330001
3^3005
3-33006
3-13007
3*13016
3*53017
409003
409006
416002
4.16003
416004
416005
419001
422007
422008
450001
450004
450005
450006
452001
VEHICLES TESTED FOR v.
-------
vcniuuti itbltU UJK 1Kb. ENVIRONMENTAL PROTECTION AGENCY CONTRACT 68-01-4319.
***** NEW YORK STATE DEPT. OF ENVIRONMENTAL CONSERVATION *****
PAGE
OWNER ' S
ID NUMBER
664352
704526
71 41 92
714398
GROSS
WE IGKT
20000
27300
08000
24000
MODEL
YEAR
1958
1970
1971
1971
ENGINE
DISPLACEMENT
300
366
318
361
XM I SSI ON
CODE
M4
M5
M4
M4
MAKE
FORD
CHEVROLET
DTDGE
DODGE
MODEL
F600
C60
PW200
D500
NUMBER OF VEHICLES 4
+ + !** NEW YORK TELEPHONE co. *****
O'/JNER1 S
ID NL'MBES
200G30
200633
200&34
2COG37
200640
200642
OWNER ' S
ID NUMBER
10704
10715
1 1338
1 G944
1G952
16056
19542
1 9392
19893
43424
43d34
4/704
477 18
47720
55467
GROSS
WEIGHT
14000
14000
14000
14000
14000
14000
GROSS
WEIGHT
50CO
50CO
5000
5000
5000
17000
15000
15000
15000
17000
17000
eooo
3000
8000
8000
MODEL
YEAR
1970
1970
1970
1970
1970
1970
MODEL-
YEAR
1971
1971
1971
1972
1972
1972
1970
1970
1970
1974
1974
1959
1S59
1959
1960
ENGINE
DISPLACEMENT
350
350
350
350
350
350
ENGINE
DISPLACEMENT
300
300
300
300
300
300
300
309
300
300
300
240
240
240
XM I SSI ON
CODE
A3
A3
A3
A3
A3
A3
<+*»*
XM I SSI ON
CODE
M4
M4
M4
M4
M4
MS
M4
M4
TvM
M'5
M5
i\W
M4
M-1
M4
MAKE
CMC
CMC
CMC
CMC
CMC
CMC
UNITED PARCEL
MAKE
FORD
FORD
FORD
FORD
FORD
FORO
FORD
F1RD
F'DRD
FORD
FORD
FORD
FORD
FORD
I-H
MODEL
3500
3500
3500
3500
3500
3500
NUMBER OF VEHICLES 6
SERVICE *****
MODEL
P500
P500
P500
P500
P500
P500
P500
P500
P500
P500
P505
P350
P350
P350
AM150M
-------
VEHICLES TESTED I OK' li.S.
CNVIRONMENTAL PROTECTION AGENCY CONTRACT 68-01-4319,
N'JMBF.R OF VEHICLES 1 5
PAGE G
791
**t-i-t UN' TED STATES POSTAL SERVICE <** + -
OWNER' S
ID NUMBER
0013-13
801425
610030
810131
GROSS
WEIGHT
21 200
2 1 200
20200
20200
MODEL
YEAR
197G
1 97 6
1976
197S
ENGINE
DISPLACEMENT
361
361
361
361
EMISSION
cone
A 4
A 4
A <>
A4
MAKE
FORD
FTRD
FTRO
FORD
MODEL
C600
C600
F700
F700
NUMBER OF
OWNER ' S
ID NUMBER
GROSS
WEIGHT
MODEL
YEAR
ENGINE
DISPLACEMENT
* t * t. k
/MISSION
CODE
WESTERN ELECTRIC
MAKE
CO. »*+
MODEL
VEHICLES
* *
25000
1970
401
M5
CMC
7500
NUMBER OF VEHICLES
OWNER1S
ID NUMBER
D7C30T
GROSS
WEIGHT
OG025
MODEL
YEAR
1977
* + **<- MISCELLANEOUS VEHICLES *****
ENGINE /MISSION MAKE MODEL
DISPLACEMENT CODE
401
A3
JEEP
CHRKEE
NUMBER OF VEHICLES
-------
-18-
IV. RESULTS
IV.A. Results Of The Inspection/Maintenance Study.
A total of 181 pairs of before-tune-up and after-
tune-up tests were performed on HD vehicles. The dist-
ributions of the vehicles by fleet, weight and model
year are shown in Tables IV-A-I and IV-A-2.
Ten vehicles were tested and retested after intervals
ranging from eighteen to twenty-four months. These vehicles
are counted twice in Tables IV-A. After such long in-service
intervals between tests it is appropriate to consider the
results of the later tests to be independent of the results.
of the earlier tests. The owners' I.D. numbers of the ten
vehicles are 10704, 10715, 11338, 16944, 10856, 19542, 19892,
19899, 47704 and 47718.
Two vehicles were already properly tuned to manufacturer's
specifications when received. Since no before-and-after
tune up comparisons could be made for these vehicles they
are not included in Tables IV-A.
The test results were .transcribed onto magnetic tape.
This massive collection of data was analyzed using the SPSS
package of statistical computer programs.(4)
The results of analyses, summarized in the following
Tables, only scratch the surface. Many important questions
about the effect of engine parameters on pollutant emissions
and fuel economy could be answered by further analysis of
the data. It is hoped that people investigating such problems
will make use of the test data file on magnetic tape described
in Appendix I.
Data from the N.Y. Quick, the C39 and the C39H driving
cycles were analyzed. Clayton Keymode results were not analyzed
because the variable format in which Keymode data were recorded
would have made analysis difficult. Also, Keymode tests were
judged to be less applicable to determining pollution effects
of on-the-road vehicles than were the driving cycle tests.
Test results for all vehicles are summarized in Table
IV-B. All vehicle were given NY Quick cycle tests. Forty-one
vehicles were also given C39 tests and eighty-nine were given
C39H tests.
-------
TABLE IV-A-1
DISTRIBUTION OF I/M TESTS BY FLEET AND VEHICLE WEIGHT
FLEET
GVriC
COUNT I
ROW PCT IBROO0
0.0
1
5.6
50.0
1.1
I
I
I
I
I
I
I
I
I
I
I
I
-T
2
8.0
100.0
2.1
0
0.0
0.0
0.0
0
0.0
0.0
0.0
I
I
I
I
I
I
I
I
I
I
I
I
-I-
6
24,0
33.3
6.3
12
23.1
66.7
12.6
0
0.0
0.0
0.0
I
I
I
I
I
I
I
I
I
I
I
I
-T-
0
0.0
0.0
0.0
1
1.9
100.0
1.1
0
0.0
0.0
o.o
COLUMN
TOTAL
14 -
14.7
16
16.8
2
2.1
12
12.6
28
29.5
2
2.1
2
2.1
18
18.9
1
1.1
ROW
TOTAL
25
26.3
52
54.7
18
18.9
95
100.0
For model year 1971 and earlier.
Top number in each group is the number of tests, second number is percent of the row
total, third number is percent of the column total, last number is the percent of
all tests on Table.
-------
TABLE IV-A-1
DISTRIBUTION OF I/M TESTS BY FLEET AND VEHICLE WEIGHT
FLEET
-------
TABLE IV~B
---
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
G39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP: ALL TESTS
Gross Vehicle Weights To 14,000 Ib.
14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year=
Prior to 1972
1972 and later
No. Of Vehicles
BEFORE.mean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
CHANGE
s.d.
NEW YORK QUICK
C39
mean _
HC
17.97
20.07
11.39
9.42
CO NOX
181
173.01
125.24
120.63
9J..93
15.98
11.18
15.32
9.41
MPG
6.59
2.64
6.84
2.76
HC
38.11
30.80
25.95
18.68
CO
41
369.44
231.48
229.89
125.96
NOX
26.56
16.14
24.77
12.22
MPG
3.59
1.30
3.83
1.25
HC
36.37
33.84
22.69
14.04
CO
89
276.21
156.93
185.98
105.43
NOX
19.06
11.60
18.31
10.13
MPG
4.32
1.47
4.42
1.50
19.05 -24.32 9.87 4.51-18.71-20.93 10.13 8.00-20.97 -24.44 7.32 4.53
35.02- 39.78 37. S3 10.66 33.68 53. fin 56.80 16.29 31.41 36.55 55.6(1 11.81
Emissions are in units of gram per mile.
Statistics for all Inspection/Maintenance tests.
-------
-19-
The pollutant levels and fuel economy before tune-up
are given on the first line. The after-tune-up levels are
given on the second line.
The third line gives the average and standard deviations
of the percent change in the measured levels for each vehicle
as a result of tune up. This is defined as:
(value after tune up) - (value before tune up)
value before tune up
Note that the average percent change shown on the third
line is not the same as the change in the average levels shown
on lines one and two.
The Table shows that, as expected, substantial reductions
in HC and CO levels resulted from tuning the engines to
manufacturers specifications. Greater percentage reductions
were produced for CO than for HC. This probably was a result
of favoring CO reduction during tune up (see Section II.A.)
The test results for NOX were surprising. It had been
expected that the decreases in HC and CO as a result of
tuning would be accompanied by an increase in NOX. However,
analysis of the pairs of before-tune-up and after-tune-up
measurements showed that any change was not statistically
significant at the 95% level. It can be concluded that the
effects of tune-up on NOX emissions were negligible.
Results of the fuel economy measurements showed that,
as expected, tuning to manufacturer's specifications results
in improved fuel economy.
Table IV-C was prepared to summarize the effect of tune
up on the vehicles tested when operating under avarage N.Y.
City driving conditions. The emissions in Table IV-C are
the averages of the NY Quick cycle results and the C39 cycle
results from TablelV-B. To prepare Table IV-C no distinction
was made between the very similar C39 and C39H cycles.
Measerements from the two cycles were lumped together, their
averages found and these averages where then averaged with
the means of the N.Y. Quick cycle measurements. ,
-------
-20-
TABLE IV-C
AVERAGES OF NEW YORK QUICK AND C39 TESTS FROM TABLE IV-B
HC CO M.P.G.
BEFORE 27.44 239.31 5.33
AFTER 17.55 160.22 5.53
Emissions are in units of gin/mi.
From emissions in Table IV-C we see that when all 181 '
vehicles drove one mile in their "as received" conditions
they emitted 5.0kg of HC and 43.4kg of CO. After tune up
their emissions wire reduced to 3.2kg of HC and 29.0kg of
CO, a net reduction of 1.8kg of HC and 14.4kg of CO.
The data in the last column shown an average fuel
economy of 5.33mpg before tune up and an average gain °.2mpg
in fuel economy from tuning. At a fuel cost of S1-30* _*ll
a properly tuned vehicle would save, on the average ,eig
dollars and eighty cents for every thousand miles driven
Useful statistics are generated by divi
tests into weight and model year catagories.
extrapolating results of the present study to groups
whose distributions of weight and model year differ from
group tested in the study.
Tables IV-D show statistics for vehicles in three gross-
vehicles-weight ranges. As expected, fuel economy decreases
wftn Increasing weight. The intermediate weight vehicles
show higher HC and CO emissions than the lighter vehicles.
However? the emissions of these two pollutants were less for
the heavy vehicles than for the intermediate weight vehicles.
A possible explanation for this unexpected result may arise
from the limitations of the dynamometer used in ^e study
which was unable to load the heaviest vehicles to full l°ad-
Had the heavy vehicles been fully loaded their emissions would
have been higher.
For reference, the results from an earlier study of heavy
vehicles conducted by the Southwest Research Institute (5) are
shown in Table IV-E. In the S.R.I, study a large group of
trucks was driven through a test cycle and their emissions
measured. The trucks were tested in "as received' condition,
-------
TABLE IV-D-1
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weights _£. To 14,000 Ib.
14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year=
Prior to 1972.
1972 and later
No. Of Vehicles
BEFOREmean
TUNE
UP s.d.
AFTER
TUNE
UP
mean
s.d.
NEW YORK QUICK
C39
C39H
HC
CO NOX
51
MPG
HC
CO
NOX
MPG
HC
CO NOX
19 .
MPG
12.Q3 1Q9.37 7.87 2.66 43.28 262.90 8.85 5.49 20.85 171.Q5 12.18 6.27
d! fin f?Q. 79 3-..qg 1-R9 28. -85 94.24 A. 54
8.25 &2.74 7.34 1Q.15 4Q.68 245.96 7.21
]^3J - 11^04 - 6^22 - 8.74 1.41
5.50 12. 56 112,50 9. 50 6.63
12.40 74.79 3.H 2.Id 37.52 76.42 3.56 1.48 5.07 61.03 2.92 1.41
% mean -18.36 -23.76 2,45 5.15 -9.0(1 15.463.3,93. 0.49 -22.22 -29.97 -4.85 7.09
CHANGE ...
S.d. 11 q? As:m 3B.g7 B.m- A4.fi! 82.16:28.21 12.14 33.9,3 26.3.9. 38.57 9,36
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight,
-------
TABLE IV-D-2
No. Of Vehicles
BEFOREmean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
3 mean
CHANGE .
s.d.
rANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
H DRIVING CYCLES FOR VEHICLES IN GROUP:
le Weight* To 14,000 Ib. Model Year= Prior to 1972.
TT 14,001 to 26,000 Ib. 1972 and later
~0ver 26,000 Ib.
NEW YORK QUICK C39 C39H
HC
21.06
22.59
13.44
9.01
-21.82
27.62
CO
205.36
148.33
145.99
99.23;
-22.88
34.36
NOX
77
12.59
5.95
12.80
5.59
21.22
77.17
MPG
6.26
1.77
6.41
1.69
3.63
11.96
HC
41.72
43.87
23.08
12.35
- 23.98
28.77
CO
13
415.20
313.76
205.98
152.81
-35.99
37.00
NOX
18.42
8.49
20.01
7.37
36.51
86.83
MPG
3.81
1.20
4.16
1.02
12.72
20.42
HC
43.33
35.21
30.39
16.23
-18.22
24.81
CO
40
292.38
155.30
216.46
112.89
-20.47
30.67
NOX '
14
6
14
6
18
72
.20
.95
.34
.06
.69
.51
MPG
4.31
0.88
4.33
0.84
1.07
9.96
Emissions are in units of gram per mile.
Statistics for inspection/Maintenance tests grouped be vehicle weight.
-------
TABLE
IV-D-3
MEANS AND STANDARD DEVIATIONS OP EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weights To 14,000 Ib.
14,001 to 26,000 Ib.
, x Over 26,000 Ib.
Model Year=
Prior to 1972
1972 and later
NEW YORK QUICK
C39
C39H
No. Of Vehicles
BEFORE.
TUNE
UP
AFTER
TUNE
UP
%
CHANGE
mean
s.d.
mean
s.d.
mean
s.d.
HC
19.20
20.26
11.44
4.99
-Ib. 11
44. 16
CO NOX
53
187.24
113.37
120.25
84.40
. 2b . yb
42.35
28.72
10.89
26.66
6.99
U. b3
31.24
MPG
4.10
0.54
4.2y
0.53
b. ±8
1X1.37
HC
34.15
21.43
22.67
8.83
-IB. by
33.51
CO
21
376". 50.
200.11
239.81
124.04
-/3. 8 /
47.43
NOX
37.50
13.90
34.01
7.03
1.4^
28.917
MPG
2.83
0.32
3.02
0.30
/ . 55
14.08
HC
36.91
37.44
18.88
8.37
37.76
CO
30
321.24
172.10
190.30
97.54
2t> . 29
46.92
NOX
29.89
10.52
28.43
8.54
-0.17
32.91
MPG
3.08
0.44
3.24
0.31
7.50
1442
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight.
-------
-21-
no tune ups were performed. The S.R.I, results and the
"before tune up" results of the present study are not
directly comparable because of differences in driving
cycles and other procedures.
Average values of HC and CO emissions found in the
S.R.I, study are of the same order as the NY Quick "before
tune up" results of the present study within a factor of
1.8. The S.R.I, result that HC emissions are almost the
same for all three weight catagories is surprising.
-------
TABLE IV-E
G.V.W.
14,000 Ibs. or less
14,001 to 26,000 Ibs.
over 26,000 Ibs.
ARD DEVIATIONS OF
DM A STUDY BY THE
\RCH INSTITUTE
#
VEHICLES
38 mean
s.d.
75 mean
s.d.
20 mean
s.d.
EMISSIONS
SOUTHWEST
HC
12.06
4.43
-11.81
5.69
12.81
11.61
CO
159.1
42.2
168.13
57.60
190.23
73.31
NOX
5.90
2.34
7.75
3.08
7.15
3.31
Units are gram/mile
-------
-22-
Tables IV-F show statistics for vehicles grouped in
two model year ranges. Model year 1972 was chosen to divide
the groups in order to emphasize differences between vehicles
built before and after the introduction of emissions controls.
The newer vehicles showed lower emissions than the older ones.
However, since the regulations governing heavy duty vehicles
are less strigent than those for autos how much of this
clifferce was the result of emissions controls on the newer
vehicles and how much was just the result of their being newer
is hard to determine.
In Table IV-G statistics are given for vehicles grouped-
be weight and model year. Enough tests were performed to
provide good statistics for each group, at least for NY Quick
cycle results. No statistics are given when less than five
vehicles were tested.
It is commonly assumed that good general maintanance is
important in control of emissions from heavy duty vehicles.
A preliminary statistical analysis of this aspect of emissions
control was made.
Prom observation of the vehicles received for testing it
vas found that the United Parcel Service fleet was excellently
maintained. In the current atudy 52 vehicles were tested that
vere in the 14,001 Ib. to 26,000 Ib. gross-vehicle-weight range
and also in the model-year-prior-to-1972 range. Four fleets
vere represented in this group; 11 from Consolidated Edison, 11
from Brooklyn Union Gas, 17 from New York City and 12 from U.P.S
For each of the four fleets the average of HC and CO
emissions during NY Quick tests were calculated and compared
with the averages for the rest of the vehicles in the group.
Only for U.P.S. vehicles were the HC and CO emissions averages
consistantly less than, and the fuel economy average consist-
antly greater than the rest of the vehicles in the group when
judged at the 95% confidence level. While this does not prove
that good maintaihance is, of itself, an important emissions
control measure it certainly supports the idea.
Statistics on I/M tests for each fleets of trucks that
participated in the study are given in Table IV-H. Statistics
are not given for cases where there were results from fewer
than four tests.
-------
TABLE --
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weight= To 14,000 Ib. Model Year= x_ Prior to 1972
14,001 to 26,000 Ib. 1972 and later
Over 26,000 Ib.
4 f'
NEW YORK QUICK C39 C39H
HC CO NOX MPG HC CO NOX MPG HC ' CO NOX MPG
No. Of Vehicles 95 .23 49
2°*89 197«98 12.99 6.. 79 42.86 424.91 21.75 3.77 40.60 288.67 14.33 4.57
UP s.d. 22.18 136.80 8.11 2.56 37.92 255.33 14.61 1.47 35.61 158.01 8.26 1.47
AFTER mean 13.82 134.12 13.41 7.09 29.1.3 226.57 iJj.UJ 4.11
TUNE
UP s.d.
11.89- 103.01 8.30 2.62 23.29 129.04 13.19 1.35 17.24 114.81 7.38 1.45
mean -16.26 -29.10 18.12 5.77-15.90 -3*6.22 23.26 12.65-20.26 27.28 12.bl b. 16
CHM*33 -Stdt . 38.69 31.21 70.54 12.14 38.52 34.34 69.54 18.40 30.78 29.59 62.20 11.61
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by model year.
-------
TABLE IV-F-2
No. Of Vehicles
BEFOREmean
TUNE
UP s.d.
AFTER mean
TONE
UP s.d.
% mean
CHANGE :
s.d.
STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
19H DRIVING CYCLES FOR VEHICLES IN GROUP:
.cle Weight* . To 14,000 Ib. Model Year= Prior to 1972.
14,001 to 26,000 Ib. X 1972 and later
Over 26,000 Ib.
NEW YORK QUICK C39 C39H
HC
14.74
17.01
8:71
4.20
-25.14
30.39
CO NOX
86
145.42
105.12
105.07
75 . 46
-19.04
47.12
19.29
13.06
17.42
10.14
0.76
36.65
MPG
6.36
2.72
6.57
2.91
HC
32.04
17.39
21.66
8.38
3.12-22.52
8.61 26.40
CO NOX
18
298:57
179.53
234.40
125.46
-0.23
67.75
3Z.70
16.30
27.13
10.71
-7.62,
25.14
MPG
3.36
1.03
3.44
1.03
HC
31.18
31.18
18.38
6.84
1.70-21.85
10.39 32.85
CO NOX
40
260.93
156.21
176.90
93.57
-20.95
43.79
24.73
12.63
23.25
10.83
0.80
46.18
MPG
4.00
1.42
3.94
1.42
1.83
11.63
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by model year,
-------
TABLE IV-G-1
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
G39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weight* _X To 14,000 Ib.
14,001 to 26,000 Ib.
« Over 26,000 'Ib.
Model Year= X_ Prior to 1972.
1972 and later
No. Of Vehicles
BEFORE- mean
TUNE
UP s.d.
AFTER mean
TUNE
.UP s.d.
CHANGE
mean
s.d.
NEW YORK QUICK
C39
C39H
HC
CO
NOX
MPG
HC
CO
NOX
MPG
HC
25
CO NOX
12
MPG
15.Q9. 122.66 7.73 9.56 45.918 271.31 7,54 5.74 22.83 165.69 11.00 6.23
15.99 £6.68 4.32 2.35 33.20 31.36T 4.41 1..3q 20.4n 7n.5£ fi:Q5 1.59
11.41 102.86 7.40 10.08 48*03 256.73
17.05 95.17 3.97 2.58 43^31 50.67
6,63. 5.66 11.93 120.27
3.95 1.76 5^53 64^Z3
9.83 6.61
3.17 _1.40
-13.41 -20.32 1.87 5.55 -2.34 -9..60 -10.91 -2.11-25.75 -25,03 ^ 5.52 7.60
42.55 3Q.60 4Q.Q7 10.64 47.67 24.17 22.93 11.67 30.16 24.87 40.50 11.03
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle Veight and model year.
-------
TABLE
IV-G-2
No. Of Vehicles
BEFORE!mean
UP s.d.
AFTER mean
TUNE
UP s.d.
CHANGE
,mean
s.d.
CANDAKD DEV-UYTJLUNS OF EMISSION AND EUJgl, ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
i DRIVING CYCLES FOR VEHICLES IN GJROUP:
le Weight* v To 14,000 Ib. Model Year= Prior tb 1972
14,001 to 26,000 Ib. jc_ 1972 and later
Over 26,000 Ib.
NEW YORK QUICK C39 C39H
HC
a.oa
11.33
5.22
2.96
24.29
22.11
CO NOX
26
ae.sa
52.68
63.39
41.25.
-27.07
55.94
8.01
3.67
7.28
2.05
3.00
38.06
MPG
9'
1.
10.
1.
4.
HC CO
2
77
35
23
56
76
6.87
NOX MPG HC
17.
9.
13.
4.
-11.
41.
46
34
81
14
16
14
CO NOX
7
180.
71.
96.
54.
-39.
28.
24
36
97
88
14
11
8
2
84-23
20
28
.20
.53
.84
.46
.58
.59
MPG
6.34
1.15
6.68
1.56
6.08
5.32
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight and model year.
-------
TABLE IV-G-3
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weight?* To 14,000 Ib.
14,001. to 26,000 Ib.
Over 26,000 Ib.
Model Year= X Prior to 1972
1972 and later
Mo. Of Vehicles
BEFORE. mean
TUNE
UP s.d.
AFTER mean
TUNE
UP ...s._d._
CHANGE
NEW YORK QUICK
C39
C39H
HC
CO NOX
52
MPG
HC
CO NOX
10
MPG
HC
CO NOX
29
MPG
24.44 231.50 11.36 6-32 47*38 492.19 17.9? ..3.59 48.82 318,35 13.51 4.30
26.41 156.73 6.18 1*77 48.70 319.07 .9.43 1.13 39.49 153.13 7.18 0.84
15713 160.01 12.40 6.51'25:24 238.65 20.58 4.05 33.28 230.70 13.58 4.43
mean
10.02 106.65 6.01 1.5& 13..18 160.59 8.17 Q.98. 17.45 115.34 6.110.86
2TT5T:-26.47 29.32 4.«l-2bi2U -JU.02 47.BO 16.39-18.40 -22.95 15.72 3.52
s.d. 27.33 31.24 89.10; 13.14 30.53 38.81 .95.38 22.02 26.15 30.91 76.04 8.35
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight and model year
-------
TABLE
IV-G-4
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GPOUP:
Gross Vehicle Weight= To 14,000 Ib.
~JT 14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year= Prior to 1972
X 1972 and later
Mb. Of Vehicles
BEFORE-mean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
% mean
CHANGE .
s.d.
NEW YORK QUICK
HC CO NOX MPG HC
25
C39
CO NOX MPG
3
C39H
HC CO NOX
11
MPG
14703150.99 14.106713
7.52 113.66 5.25 1.79
12.22 145.89 6.24 0.98
9.93 116.83 13.64 6.20
4.96 75.48 4.60 1.93
23.03 180.20 16.26 4.07
9.78 102.43 5.77 0.77
227T5-lb.41TTJT7ET
28.76 3SL.74 39L.3S 8.75
-ly.yb -14.13 18.62 -5.16
22.17 34.21 66.09 10.67
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight and model year.
-------
TABLE IV"G"5
Nd. Of Vehicles
BEFORE mean
TUNE
UP _ s.d.
AFTER mean
TUNE
UP _ s.d.
mean
s.d.
STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM
5H DRIVING CYCLES FOR VEHICLES IN GROUP:
=le Weights To 14,000 Ib. Model Year= X
14,001 to 26,000 Ib.
JC_ Over 26,000 Ib.
<
NEW YORK
HC
18.69
13.12
13.42
7.50
-5.03
57.00
CO
205.75
108.04
105.89
86.20
-48.88
24.22
QUICK
NOX
18
23.56
7.75
24.69
7.72
8.34
23.56
C39
MPG
4.28
0.63
4.62
0.53
8.84
11.11
HC
35.28
27.17
22.17
8.81
-12.74
43.60
CO
8
431.42
227.80
iy2;bi
110.92
-50.62
26.25
NOX
35.33
13.04
J0.1J
6.84
13.93
37.52
MPG
2.
0.
O
0.
17.
12.
77 37
34 31
" 23
28 14
19-15
77 45
HC
.'46
.16
.30.
.63
.bl
.31
NEW YORK QUICK,
Prior to 1972 .
1972 and later
' C39H
CO NOX
8
365.57 22.92
182.37 8.94
173.39 22.92
124.12 9.20
-45. /y J. J /
27*29 27.15
MPG
2.93
0.52
J.Ub
0.61
Ib . 66
16.99
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight and model year,
-------
TABLE IV-G-6
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:
Gross Vehicle Weight= To 14,000 Ih.
14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year= Prior to 1972 .
X 1972 and later
No. Of Vehicles
BEFOREmean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d. .
% mean
CHANGE .
s.d.
NEW YORK
HC
19.45
2T ?7
10.42
2.62
20.29-
QUICK
CO NOX.
35
177.72
127.64
83.74
>*15.67
31.38
27.67
6. 46
-3.49
C39
MPG
4.01
0.46
4.12
0,45
3.30
HC
33.37
18- 2 5
23.00
9.23
-22.66.
CO
13
342.92
182.31
271.27
126.67
-6.04
NOX
38.83
14.76
32.40
6.96
-6.93
MPG
2.86
0.31
2.89
0.23
HC
36. -n
40; 15
17.34
4.23
1.13-26.82
C39H
' CO NOX
22
305.13
169.68
196.18
89.06
-19.20
32.42
10.05
30.35
7.59
1.46
MPG
j.uy
0.37
3.16
0.28
4.17
36.86 45.44 34.15 9.59 26.21 50.79 19.06 11.23 35.34 "50.93 35.26 12.14
' Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by vehicle weight and model year.
-------
TABLE IV-H-1
Mo. Of Vehicles
BEFORE
TUNE -
UP
AFTER
TUNE
UP
%
CHANGE-
mean
s.d.
mean
s.d.
mean
s.d.
STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM
39H DRIVING CYCLES FOR VEHICLES IN GROUP: BROOKLYN UNION GAS
icle Weight* To 14,000 Ib. Model Year= _
14,001 to 26,000 Ib. __
Over 26,000 Ib.
«
NEW YORK QUICK C39
HC
31.36
18. Q2
24.13
10.77
-16.94
21.40
CO
226. Q8
109.24
181.21
sa.se
-17.17
28.22
NOX
11.90
5.39.
12.30
4.80
18. QQ
62.42
MPG HC CO
Q
5
1
5
1
2
7
.37
.15
.50
.25
.53
.98
NOX MPG
50
27
40
18
-12
23
HC
.46
.96
.47
.52
.40
.69
NEW YORK QUICK,
Prior to 1972 .
\ 1972 and later
.-
C39H
CO NOX
17
308.
137.
246.
124.
-18.
25.
79.
01
ad
55
7
37
14.23
6.37
14.23
6.76
.
38.64
MPG
J.
Q.
*
0.
3T
10.
95
78
09
89
62
59
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped By fleet.
-------
TABLE
- H- 2
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP: CONSOLIDATED EDISON
Gross Vehicle Wei#it= To 14,000 Ib.
14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year=
Prior to 1972.
1972 and later
Ho. Of Vehicles
BEFORE.mean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
CHANGE
NEW YORK
30
34
HC
.48
.43
CO
321.59
176.77
QUICK
NOX
21
13.90
7.76
C39
MPG
5.17
1.56
HC
56.96
43.36
CO
14
491.35
298.62
NOX
19.89
10.73
MPG
3.46
1.07
HC
53.05
56.36
C39H
CO NOX
7
421.91 13.19
168.98 10.74
MPG
3.81
0.71
mean -
s.d.
17.29 233.74 14.62 5.30 36.50 279.52 20.58 3.75 21.72 308.54 11.74 3.90
yi. OS" 128. 4B 10.00 1.32 27.54 130.17 12.22 0.81 9.03 55.92 5.47 0.89
24.73 -5.62 20.42 5. 24-21.02 . -13 . 73 14.52 12.15-43.65 -12.47 10.41 5.95
44.79 63.19 103.48 18.14 41.67 70.05 72.78 20.46 27.45 32.33 84.66 18.74
Emissions are in units of gram per mile.
Statistics for inspection/Maintenance tests grouped by fleet.
-------
TABLE IV-H-3
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLER FOR VEHICLES IN GROUP: N.Y. CITY DEPT. OF SANITATION
Gross Vehicle Weight* To 14,000 Ib.
' 14,001 to 26,000 Ib.
. Over 26,000 Ib.
Model Year=
Prior to 1972.
1972 and later
No. Of Vehicles
BEFORE"mean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
%
CHANGE
mean
NEW YORK QUICK
C39
C39H
HC
CO NOX
47
MPG
HC CO NOX MPG
19
HC
CO NOX MPG
28
17.71 178.36 3Q.23 4.02 29.54 341.23 38,28 2.85 35.30 322.70 31.23 3.05
20.79 111.12 10.40 0.4916.82171.79.13.50 0.32 37.96 173.89 3.54 0.42
10.32 114.96 27.62 4.19 21,70 231.40 33.54 3.02 17.10 189.65 29.45 3.20
L2-68 81.6-8 6.15 0.43 8.22 125.291 6.45 0.29 4.70 99.20 7.85 0.28
-12.70 <-25.76 -1.21 5.04-14.91-20.26 -3.87 6.51-24.04 -26.16 -1.93 7.46
's.d. 46.49 44.30 31.92 10.82 32.29. 48.71 20.67 14.41 38.92 48.52 33.20 14.79
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by fleet.
-------
TABLE
IV-H-4
No. Of Vehicles
BEFORE-mean
TUNE
UP s.d.
AFTER
TUNE
UP
%
CHANGE
mean
s.d.
mean -
s.d.
STANDARD DEVIATIONS OF EMISSION AND FUEL BOONCM* MEASUREMENTS FROM NEW YORK QUICK,
9H DRIVING CYCLES FOR VEHICLES IN GROUP :N.Y, CITY DEPT. OF WATER RESOURCES
cle Weights To 14,000 Ib. Model Year= Prior to 1972.
14,001 to 26,000 Ib. 1972 and later
, Over 26,000 Ib.
NEW YORK QUICK C39 C39H
HC
13.88
15.18
8.6Q
6.37
19.98
28.16
CO NOX
59
133 . 97
84. Q7
35.61
62.5.6
-27.25
sa.ia
9.46
5.Q6
9.13
3.97
11.49
51.00
MPG HC CO NOX MPG
0
8
2
8
2
6
8
.32
.26
. 82 .
.45
.21
.31
30.
29.
19.
11.
-20.
33.
HC
45
63
32
55
bl
21
CO NOX
24
210.75
126.52
145.16
75.80
-23 . 3.4
36.21
12.
7.
11.
5.
17.
81.
44
91
39
27
01
34
MPG
5.
1.
b.
1.
3.
7.
61
48
/y
67
89
94
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped By fleet,
-------
TABLE IV~H~5
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP:UNITED PARCEL SERVICE
Gross Vehicle Weight= To 14,000 Ib. Model Year= Prior to 1972
14,001 to 26,000 Ib. 1972 and later
Over 26,000 Ib.
<
NEW YORK QUICK C39 C39H
No. Of Vehicles
BEFORE
TUNE
UP
AFTER .
TUNE
UP
%
CHANGE
mean
s.d.
mean
s.d.
mean
s.d.
HC
10.85
A 84
7.47
3.03
-25.02
26.00
CO NOX
25
101.72
fn K"\
63.08
44.96
-37.7JB
27.90
11.05
= 79
10.77
4.71
9.39
63.80
MPG HC
2.30 26.19.
i
-------
TABLE
- H- 6
MEANS AND STANDARD DEVIATIONS OF EMISSION AND FUEL ECONOMY MEASUREMENTS FROM NEW YORK QUICK,
C39 AND C39H DRIVING CYCLES FOR VEHICLES IN GROUP: UNITED STATES POSTAL SERVICE
Gross Vehicle Weights
To 14,000 Ib.
14,001 to 26,000 Ib.
Over 26,000 Ib.
Model Year=
Prior to 1972
1972 and later
No. Of Vehicles
BEFORE-mean
TUNE
UP s.d.
AFTER mean
TUNE
UP s.d.
a msan
CHANGE
s.d.
NEW YORK
17
11
7
3
-52
15
HC
.88
.70
.54
.03
.08
.51
CO
265.
200.
141.
37.
-20.
65.
44
25
40
78
87
53
QUICK
NOX
4
17.
5.
16,
1.
6.
46.
04
39
36
75
37
65
MPG
4.
0.
4.
0.
4.
13.
C39 C39H
HC CO NOX MPG HC CO NOX MPG
Q °
72
60
90 .
22
94
90
Emissions are in units of gram per mile.
Statistics for Inspection/Maintenance tests grouped by fleet.
-------
-23-
IV.B. Result Of The Retrofit Study.
IV.B.1 Screening
A goal of the study was to identify the best non-catalytic
emissions controls by screening and testing coiranerically avail-
able device.
Extensive screening and preliminary testing had already
been accomplished in an earlier study of both catalytic and
non-catalytic device (2). The present study incorporates the
results of the previous study wherever possible.
A list of non-catalytic devices that were screened is
given in Table IV-? Factors that were considered include
emissions reductions, effects on safety, driveability and fuel
economy, ease of installation and maintainance and cost, including
installation and maintance costs.
Some devices were identified by screening as unsuitable.
Preliminary test showed others to be unacceptable. Summary
descriptions of these units are given at the end of this section.
The preliminary test results, if any, can be found in Appendix
-L X _L
Screening and initial testing produced three candidates
for further investigation in this study: exhaust gas recircula-
tion devices, air bleeds and lean mixture carburetors.
Exhaust gas recirculation devices:
Exhaust gas recirculation is a well-known control technique
for oxides of nitrogen. NOX is formed by high temperature oxida-
tion of nitrogen during combustion. EGR reduces peak combustion
temperature by introducing a quantity of basically non-reactive
gas (exhaust) into the combustion chamber. There are undesirable
thermodynamic consequences of EGR, such as lowering peak cycle
temperature, which reduces engine efficiency and thus fuel
economy.
Two EGR systems tested in this program are the DANA
"Retronox" and the STP systems. The two systems have much in
common. Both use an externally mounted aluminum body valve to
control EGR both route the exhaust into the manifold via the PCV
line, and both make use of two additional control approaches,
air bleed and vacuum spark advance modification.
-------
TABLE IV-I
NON-CATALYTIC DEVICES SCREENED
Device Name
Adaks Vacuum Breaker
Air Jet/Ball-Matic
A.Q.P. Pure Power
Clear Air International
Care System
Echlin
Description
Air bleed with carburetor spacer plate
Air bleed to PCV line Spark advance,
capacitor discharge
ignition system
Air bleed to PCV line
Modified PCV system with air bleed
Spark advance plus air bleed
Gas Atomizer/Econoneedle
Air bleed mixture screw
G-R Valve
Hydrocatalyst
M.S.D.
Patco
Paton
Pollution Master
Retronox
Rochester, Motorcraft
and Holly carburetors
Smogmaster
STP-EGR
STP-Air Computer
Air bleed to PCV line
Screen under carburetor
Electronic ignition system
Chemical injection
Heated air bleed to intake manifold
Air bleed to intake & exhaust manifolds
EGR plus air bleed, timing mod.
Lean mixture carburetors
Air bleed to PCV line
EGR plus air bleed, timing mod.
Air bleed to PCV line
-------
-24-
In both systems, manifold vacuum is the signal which
controls EGR valve operation. In the DANA system, ported
manifold vacuum above a certain point (about 3- inches Hg)
opens the valve and allow exhaust gas to flow. Thus EGR
is blocked out during low vacuum (acceleration) modes,
and since ported vacuum is used, there is no EGR during
idle. The STP valve, in addition to controlling EGR,
also controls filtered bleed air from the air cleaner.
During idle and low cruise modes, both exhaust gas and air
flow into the intake manifold. Low vacuum modes, such as
acceleration and high speed cruising, close the air bleed
and allow full EGR flow. Upon decelerating, the EGR is
closed and bleed air alone flows through the valve.
In the DANA system, the air bleed function is
accomplished through the use of an increased-flow PCV valve
replacement. Both systems use vacuum delay valves (VDV's)
to delay the onset of distributor vacuum advance as an HC
control measure. On the DANA system, the VDV also delays
EGR valve opening on sudden changes in vacuum.
Air bleeds:
The air bleed-type device operates by admitting extra
air to lean out the air/fuel mixture during certain modes
of operation, thus reducing CO concentrations. Of the many
air bleeds screened, those which gave the best result were
vacuum operated? the amount of air bled to the intake mani-
fold is directly related to manifold vacuum. This means
that the lean-out occurs during the characteristically high
vacuum modes of idle and deceleration. During low vacuum
modes, such as high speed cruising and acceleration, the
valve is closed.
The bleed air can be brought into the intake manifold
in one of two ways. The way common to most of the devices
was by tapping into the rubber PCV hose near where crankcase
vapors enter the intake manifold. This method is undesirable
for two reasons; 1) it can lead to malfunctioning of the PCV
valve or allow emission of crankcase vapors, and 2) it may
lead (on some engine models) to an uneven air/fuel mixture
distribution to the cylinders.
-------
-25-
The second method is to use the carburetor spacer plate.
This plate, usually of one-half inch aluminim, is installed bet-
ween the carburetor and the intake manifold. This arrangement
assures adequate mixing of the bleed air, but entails a more
involved installation procedure. Longer carburetor mounting studs
may be required, and choke and throttle linkages adjusted for
the raised, carburetor. Nevertheless, the spacer plate must be
considered the preferred method of air bleed installation on the
basis of observed emission reductions.
One device which emerged early in the program and was the
only air bleed-type device to receive full test treatment, was
the ADAKS Vacuum Breaker. This device features a piston-in-oil
damped bleed valve, a replaceable foam-type air filter, and an
aluminum spacer plate.
Five pre-adjusted ADAKS devices were supplied by the manu-
facturer. Emissions data indicated that these pre-set versions
are not as effective as device properly adjusted using an exhaust
gas analyzer. Actual physical deterioration of the ADAKS device
is expected to be negligible. The manufacturer recommends periodic
replacement of the air filter; they never needed replacement in our
study. Other maintenance should include checking the hose for
leaks, checking the oil level in the valve and having the bleed
setting checked by a mechanic skilled in the use of the CO/HC
analyzer. A one-year maintenance interval is reasonable. The
manufacturer estimated the cost of the device, including install-
ation, to be under $100. Cost will vary somewhat due to the
different adaptor plates required on various engine.
-------
-26-
Lean mixture carburetors:
The 1973 California HD Vehicle Emission Standards called
for emission reductions estimated at 67% for CO and 47% for
HC and NOX compared to uncontrolled vehicles. These standards
became national in 1974. Despite the large percentage reduction
indicated, heavy-duty engine manufacturers were able to attain
the new CO standard almost entirely through carburetor modifica-
tions .
The newer carburetors/ hereafter referred to as lean
carburetors, are not very different in outward appearance from
the devices they replace. The fact that they can be easily
installed by a mechanic of average skill level makes it a
prime candidate as a retrofit device.
The main difference in a lean carburetor is the quality
control level in recent carburetor production. (7) Whereas the
air/fuel ratio tolerance used to be in the neighborhood of 10%,
engine manufacturers, under pressure to meet emission standards,
are now asking for 3% tolerances. Most carburetors manufactered
today are individually flow .tested. With greater confidence in
air/fuel ratios, carburetors can be designed much leaner without
fear of straving the engine.
Lean carburetors, depending on the specific model, may
differ in other ways. Idle mixture limiter caps, pre-set at the
factory to optimum air/fuel ratio or permitting a small range
of adjustment, prevent, to some degree, excessive enrichment at
idle. Power enrichment and accelerator pump circuits may be
modified. Idle stop solenoids prevent dieseling on engine shut-
off. Automatic chokes are designed to open sooner.
Three manufacturer's examples of lean carburetors were
tested in this program. They are the Rochester Carburetors for
General Motors trucks, the Motorcraft for Ford trucks, and the
Holley for International trucks.
Deterioration of lean carburetors is nor expected to be an
important consideration, except as a result of improper mainten-
ance, especially the removal of idle limiter caps. Enriching
the idle mixture is the mechanic's traditional cure-all for a
poorly running engine.
Some deterioration in vehicle driveability, notably accel-
eration and cold-start performance, may occur with lean carburetors.
This effect was not of such a degree as to cause any adverse driver
comments during this program.
-------
-27-
Availability of devices is limited to those engine
families for which a carburetor redesign took place. Many engines,
of course, have been dropped from production. The most popular
HD engines, however, are still being produced and are therefore
candidates for lean carburetor retrofit.
Prices of the carburetors vary from about $50.00 to above
$125.00
-------
-28-
IV.B.2 Results - Exhaust Gas Recirculation Devices.
Exhuast Gas Recirculation devices were promising candidates
for a retrofit program and were specified as one of the controls
to be tested in the study.
Preliminary testing was done on the DANA Retronox and the
STP EGR devices. These devices were manufactured .in response to
an anticipated requirement for retrofit of older autos with NOX
controls that was expected to be enforced in California(8).
However, the requirement was never put into effect, possibly
because too low a price limit, $35 installed, had been set for
the devices. By the time the study was ready to start serious
testing of EGR devices they were no longer being -manufactured for
retrofit and were unavailable.
Results from preliminary test of the DANA device will be
discussed. These were installed on three trucks. Emissions and
fuel economy in tuned up conditions were measured immediately
before and after installation. The vehicles were then returned
to service. They were occasionally recalled and retested for a
period up to a year and a half.
Graphs of the measured levels of HC, CO, NOX and fuel economy
are given in Appendix II. The graphs show the level with the
device installed. For comparison, the level immediately prior to
installation is shown by a dashed line.
Caution must be used in interpreting the dashed line as a
constant level against which later measurements can be compared. It has been
found that emission levels from vehicles can vary substantially
with time depending on the general condition of the vehicle.
Therefore variations of emission levels probable have more to do
with the service and maintainance histories of the vehicles than
with the durability of the control device.
DANA claimed, on the basis of tests on a single auto, that
reductions of 19% in HC, 47% in CO and 65% in NOX could be
achieved. The preliminary test results for heavy duty vehicles
indicate that CO levels were reduced up to 50% and NOX up to
40%. Changes in HC levels were minor and there was a small improve-
ment in fuel economy.
Unlike RETROFIT tests on other devices all the DANA tests
were run using the 72H driving cycle. (9)Had testing been continued
the New York Quick and the C39 would have been used.
-------
-29-
Both the' STP and the DANA systems, which were approved
for sale in California's light-duty vehicle retrofit program,
showed vulnerable points in HD vehicle application. The VDV's
in both systems had a tendency to become clogged with dirt, thus
cutting off all vacuum advance and, in the case of the Retronox,
stopping EGR function as well. The corrugated metal hose supplied
with the DANA kit, good in its tendency to keep the EGR valve
cool by dissipating heat, can crack if bent too often in installa-
tion.
The hose supplied with the STP kit was clearly inadequate
for EGR work. Several of these had to be replaced. Installing
EGR systems was complex and time consuming. STP claimed install-
ation of their device in autos took about fifteen minutes.
However, each model of heavy duty" vehicles required a unique
installation procedure and took much longer.
No adverse driveability effects were found as long as the
devices were operating properly. Out-of-adjustment devices did '
produce drivability problems. This indicates that adequate
maintenance of EGR devices in heavy duty vehicles is important
and that maintanance costs may be increased.
-------
-30-
IV.B.3 Result's - Air Bleeds.
Results of HC, CO NOX and fuel economy measurements for
eleven vehicles with the ADAKS device are given in Appendix II.
Levels with and without the device are shown. The "without"
values were measured with the air inlet to the device plugged,
making it inoperative.
Experience with HD vehicle emissions suggests they are
strong dependent on the general condition of the vehicle and
its engine/ As a result it should be expected that periodic.
testing of in-service vehicles would show considerable variation
in emission levels from test to test. This assumption is
supported -by the results in Appendix III which show large
variations in levels both with and without the device. .
Figures 4-A through 4-J show plots of the percent change
in emissions and fuel economy achieved by ADAKS in ten vehicles.-'
Reductions in HC and CO varied widely from test to test. Also
shown in the figures are the means and standard deviations of
the percent changes. .
The following Table summerizes the data for ten vehicles
tested with ADAKS:
TABLE IV-J
PERCENT CHENGE IN POLLUTANT LEVEL AND FUEL ECONOMY- PRODUCED BY ADAKS
POLLUTANT HC CO NOX FUEL ECONOMY
' (GRAMS PER MILE) M.P.G.
Mean % change -2.40 -44.74 8.74 2.34
Standard error of the mean 8.04 6.62 3.80 1.82
The results in Table can be compared with results of tests
performed on a different grpup of vehicles in the Grant study.
jn that study their Table 9 reporting tests on 7 vehicles shows
xroughly the same changes in CO and fuel economy. They-reported
substantially larger reductions in HC and NOX possibly due to
the large scatter in their results and also in the present results
for these two pollutants.
-------
-31-
I00.0E
90.00
B0.00
70.00
E0.00
50.00
H0.00
[J 30.00
in
"-^ 20.00
IT 10.00
_L0J30
-10.00
j 20.00
*- -30.00
y
M -H0.00
LL 50.00
LJ
,-j -50.00
-70J30'
B0.00'
-30.00'
CHRNEE IN LEVEL FDR VEHICLE I 133B WITH RDRK5.
+ HC RVE» -22.02 5TRN. DEV.r I B.92
X CD -23.72 29.17
D.NDX -H.BB I5.3B
X M.P.G. -H.BB II. I 7
H 1 H
H 1 h
~{
WHWHWHWBMHUlHUIHblHWHWH
* *
TJJl/ll/Il/IMlfllDlDIDhhh^IDQI'IDIDIII
^^^^^^^^^^^^^^^^^^^^
DlQIDIDIDlDiniDlDlIIIDIDIQininiDlDiniinill
DRTE DF TE5T
Fig. 4-A Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-32-
I 00.00
90.00
B0.00
70.00
E0.00
50.00
H0.00
120.00
[J 30.00
13;
rr 10.00
10.00
-10.00
|- -20.00
£- -30.00
y
II -H0.00
C-S0.00"
y
P. -E0.00
-70.00
-B0.00
-90.00
CHRNEE IN LEVEL FDR VEHICLE IE9HH NITH RDRK5.
+ HC RVE.: -10.3H 5TRN. DEV.= 37.73
x CD -30s i Haas:
D NDX -1.73 I 1.35
* M.P.B. -0.EH H.EE
^iiiiiiih
1 - 1
1 - 1 - 1 - 1 - 1 - 1 - 1
I h
H ni M h H
ni oi ni ni ni
N U h H N M h H 'N M h El N M I
oiDiDinininiiniiiDioiDiDioiDininimDinini
DRTE DP TE5T
Fig. 4-B Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-33-
1 03.32
30.03
B0.0E!
70.00
E0.00
£0.00
H0.00
U 30.00
13 20.00
Z
rr 10.00 '
10.00
-10.00'
U- -20.00
Z -30.00
Ul
I-H0.00
Pi -50.00
. 1
^ -50.00'
o.
-70.00'
-,80.00
-30.00
*
^
CHRNGE IN LEVEL FDR VEHICLE 1E9S2 WITH RDRK5.
+ HC RVG- 3B.BB 5TRN. DEV.:
X CD -2B.SH
D NDX -E.7H
X M.P.G. I.B0 +
*
t
* x
0
' '.'''' * ' '
^ 5!^ g W B M B W BU1BUIBVIBUBMB
NMhBNMhBNMhaNUhBWMhB
J J 7 W I/I M M ID 10 ID ID b H h h Ol (D D OJ OJ
0101010101010101010101010101010101010101
DRTE DF TEST
Fig. 4-c Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device,disconnected). ; .
-------
-34-
100.00
30.00
B0.00
70.00
EIZ.00
E0.00
H0.00
[J 30.00
ID
Z
rr 10.00
10.00
-10.00
(- -20.00
*- -30.00
111-
M -H0.00
20.00
LJ
D.
E0.00
-70.00
-B0.00
-30.00
I 1
CHRNEE IN LEVEL FDR VEHICLE IB0SE WITH HDRK5.
+ HC RVE.= B.0H 5TRN. DEV.= 22.27
X CD -H9.2H IE.HI
D.NDX 1.69 I7.3H
3K M.P.E. -2.35 2.E2
H 1 1 1 1 1 1 1 1 1 1 1 \ 1 1 1 1 1 1 1
U1SI/1HI/1H1/1HI/1S1/1HI/1B1/1BWSI/1B
DimoiDioimininniniDiQiniDiniDiDiDiDiin
DRTE DF TE5T
Fig. 4~D Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-35-
100.00
30.00 '
B0.00
70.00
60.00 '
33.00 '
H0.00
130.00 '
'20.00
Z
IT 10.00
10.00
V
-10.00
30.00
| 20.00
Z_.
u
M -H0J20
H -50.00
p. -B0.00
-70.00
-B0J20
-g0jznzr
i(
CHRNEE IN LEVEL FDR VEHICLE I95H2 WITH FIDFIK5.
+ HC FIVE- 1.17 5THN. I>EV.= 17.73
X CD -33.05 9-99
D.NDX 5.1 H 10.75
X M.P.B. LSI 2.05
H 1 1 1 1 1
H 1 1 1 1-
JJJl/lWWMlDtDlDlDhr-hNIDIIllDffiin
^^^^^^^^^^^^^^^^^^^^
DiDioiDiDiDiniDiniDiainiDiDiDiDioiniinni
DRTE OF TE5T
Fig. 4-E Percent in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-36-
100.00
50.00
H0.00
70.00
E0.00
50.00
H0.00
L-'20.00
n~ 10.00
10.00
-10.00
I 20.00
*- -30.00
bJ
M -H0.00
II -50.00
r, H50J30
-70.00
B0I30'
I 1
CHRNEE IN LEVEL FDR VEHICLE 19392 WITH RDRK5.
+ HC fWG.= IB.3H 5TRN. DEV.= HB.7B
X CD -73.73 7.30:
D.NDX 0.3
X MP.E. 0.B7 /\ B.23
H 1 1 1 1
T j j u i/ w
ID ui ui ui
ni o ID
n
t>RTE DF TE5T
Fig. 4-F Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-37-
100.00
30.00
B0.00
70.00
B0.00
50.00
H0.00
[J 30.00
in
u 20.00
rr 10.00
Z0.00
-10.00
j 20.00
^30.00
y
M-H0J30
LL-50.00
U
Q. mm
-70.00
-B0.00'
-30.00'
CHRNEE IN LEVEL FDR VEHICLE 200E30 WITH HDHK5.
+ HC RVB.r 2H.2B 5TRN. DEV.r
X CD -EH.EH
D. NDX 31 SB
* M.P.E. I9.HS
J T T M w i/i i/i ID" ID" ID ID K K K K oi ni ni m' ni
ntOlDIDIDlDlinDIDIDIDIDIDIDlinDlDlDlinDl
DRTE DF TEST
Fig. 4-G Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-38-
100.00
90.00
B0.00
70.00
E0.00
£0.00
H0.00
JJ 30.00
in
'20.00
Z
rr 10.00
10.00
-10.00
I 20.00
^ -30.00
y
l| -H0J30
H -S0J30
y
pi
m
-E0.00
-70.00
-00.00
-30.00
I - 1 -
CHRNEE INT LEVEL FDR VEHICLE 200EH0 WITH RI>RK5.
I- HC RVE.r -37.35 5TRN. DEV.: H1.55
X CD -57.30 15.27
D NDX H5.B5 23.72
5K M.P.E. 3.7H 1.7E
H 1 1 1 1 1 1
j j j w
w M ID i u u
n o i n n
t>RTE DF TE5T
Fig. 4-H Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-39-
100.00
30.00
B0.00
70.00
E0.00
50.00
H0.00
U 30.00
H] 20.00
Z
rr 10.00
0.00
V
-10.00
|- -20.00
^- -30.00
U
i i -H0.00
y
-S0.00
-60.00
-70.00
-B0.00
-90.00
1 1
CHRNEE IN LEVEL FDR VEHICLE H3B3H WITH RDRKS.
+ HC RVE.= -3.27 5TRN. DEV.r IB.BS
X CD -33.E2 13.52
D-NDX 9.H5 3.B0
5K M.P.E. 2.51 5.2H
H 1 1 1 1 1 1 1 1 1 1 1 1 1 1I 1 1 1 1
J J T U I/ M M ID ID ID ID
^I^^^JS^I^^^^f^
DimniniDiDiDininiDiDi
DRTE DF TE5T
Fig. 4-1 Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-40-
100.00
30.00
B0.00
70.00
60.00 '
50.00 '
H0.00 '
jjj 30.00 '
'-'20.00 '
rr 10.00 '
1 0.00 '
-10.00'
\- -20.00'
*- -30.00'
Id
M -H0.00'
LL -50.00'
n -60.00'
-70.00'
-B0.00"
-90.00'
i i
i i
CHRNGE IN LEVEL TOR VEHICLE H77DH NITH RDRK5.
+ HC RVE - -33. 1 H 5TRN. DEV.= 9.H5
X CD -H0.EB 15.21
D- NDX B.77 II. HE
* M.P.E. \JBK 2.H3
\
j" * ^ *
^* * \ *
*^ \
N,
N(\ ^
/ ^^\*^>^*
/ ^^^^
/
i i i i i i i i i i i i i i i i i i i i
i i i i i i i i i i i i i i i i i i i i
WHt/1EWHl/1Hl/1HU1HU1Hl/lSl/1HWH
Nl/lhHNl/lhHRIl/lhHniMhHNMf^H
T T j t/i i/i i/i M" ID ID ID ID K S h K ni ni id ni m'
DiniDiDiDiainimDinininiQiDiniDiDininiQi
DRTE DF TEST
Fig. 4-J Percent change in emissions and fuel economy
produced by ADAKS (compared with level measured
with device disconnected).
-------
-41-
IV.B.4 Results - Lean Mixture Carburetors.
The significant improvements in the emissions levels and
fuel economy of light duty vehicles that results from improved
carburetors suggest that similar improvements would result from
retrofitting older HD vehicles with new carburetors.
Tests were made on two 1971 vehicles, a 1970 vehicle and
a 1959 vehicle. Other vehicles were tested but the results
could not be used. One of the vehicles became unavailable for
further testing after retrofit. For another vehicle ignition
system malfunctions invalidated the test data. Data from all
carburator retrofit tests are contained in Appendix III.
Vehicles in the carburetor retrofit study were tuned up
and their HC, CO, NOX and fuel economy levels were measured*
They were then retrofitted with the most modern carburetors that
matched the engine and were again tested. The vehicles were
returned to service and were periodically retested.
Graphs of the NY Quick cycle results are given in Appendix
II. A dashed line on each plot shows the level immediately prior
to retrofit. Caution should be used in interpreting the dashed '
line representing a single measurement, as a constant level
against which all later level can be compared.
The percent change in emissions level, produced by lean
carburator (I.e..) retrofit, defined as
100 X (level after I.e. retrofit - level before I.e. retrofit)
level before I.e. retrofit
are shown in Table IV-K. in the table results from tests on 4
vehicles in the present study (nos. 10704, 10715, 19899 and 47720)
are grouped with results from tests on 11 vehicles made during the
Grant study
A mean decrease of emissions levels is shown for all three
pollutants. However, the standard errors of the mean are large:
5.6 for HC, 9.0 for CO and 6.3 for NOX. Only for CO is the mean
percentage reduction statistically significant at a 95% level of
confidence.
The 4 vehicle in the current study showed a modest average
increase in fuel economy of 3.6% after retrofit. While this was
not significant at the 95% level the previous study on 11 vehicles
also reported a "small" increase in fuel economy.
-------
-42-
The small size of the average reductions in emission
shown in Table IV-K does not mean that lean carburetors are
inadequate for HD retrofit. As discussed in the CONCLUSIONS
section, the small reductions result from limitations in the
study rather than limitations of lean carburetors as control
devices.
TABLE IV-K
:NITIAL CHANGE IN EMISSIONS UPON INSTALLATION OF A LEAN MIXTURE CARBURETOR
OWNER'S - MODEL PERCENT CHANGE
I.D. No. YEAR HC CO NOX
47720 1959 13.5 2.6 -6.9
252-284 1969 -24.7 -33.1 6.0
4200 1961 8.6 7.6 -8.4
19899 1970 23.9 69.5 -22.7
25D369 1970 -0.2 5.9 -26.0
10704 1971 -11.5 -51,4 23.7
10715 1971 3.7 -19.8 1.1
4160 1971 -3.5 -11.2 -25.1
4177 1971 -26.4 -56.0 -18.7
4205 1971 -23.4 -42.3 1.4
4206 1971 -20.3 -30.4 22.2
4215 1971 -42.4 -70.5 63.1
4220 1971 38.1 1.5 -21.9
4418 1972 -11.1 -48.4 -14.4
4633 1972 -21.2 -25.4 -22.5
Mean -6.5 -20.1 -3.3
s.d. -21.5 -34.8 24.5
-------
-43-
IV. B. 5 Description Of Devices Screened.
Herein are brief descriptions of those devices tested in the
screening phase.
BALL-MATIC (also marketed as "AIR JET")
This device is representative of a series of small, air bleed
type devices which are inserted into the PCV line between the PCV
valve and the intake manifold. The device contains a non-adjust-
able ball check valve which is normally open but which closes.
under high manifold vacuum conditions, the exact opposite of
vacuum-opening type devices. The flow of air is so high under
low vacuum conditions that misfire may occur at high speeds.
These devices may also allow crankcase emissions.
AIR QUALITY PRODUCTS - "PURE POWER"
The Pure Power exhaust emission control system is a capacitive
discharge electronic ignition, system. The system monitors
engine revolutions and computes correct spark timing signals to
control emissions and raises the sparking voltage to improve
combustion effectiveness at all engine speeds.
CLEAR AIR INTERNATIONAL
This is a vacuum-operated air bleed which feeds into the
pCV line. Valve spring tension is adjustable and installation
the use of an exhaust analyzer.
C.A.R.E. SYSTEM
This system replaces the vehicle *s crankcase ventilation
system and provides heating of crankcase vent air plus additional
t>leed air. Air enters the crankcase via an air tube containing
a flow valve (replacing the vehicle's PCV valve) and a filter.
Upon exiting the crankcase, the air passes through a copper tube
clamped to the exhaust manifold where it is heated. The air
enters the intake manifold. Additional bleed air is introduced
through a separate variable orifice and filter.
-------
-44-
ECHLIN
This system combines air bleed and V.S.A.D. functions. The
air bleed is referred to as an "ultra-sonic generator" which is
alleged to enhance the combustion process. A carburetor spacer
plate is enclosed, as is a plug for the distributor vacuum line.
GAS ATOMIZER (also marketed as ECONONEEDLE)
These devices replace the carburetor idle fuel adjusting
screws. The device consists of a needle screw with an bleed hole
drilled through the center. It is claimed that this carburetor
modification for lean air-to-fuel mixture in idle and deceleration
modes results in reduced fuel consumption and exhaust emissions.
G-R VALVE
Refer to "BALL MATIC" description.
HYDROCATALYST
This device consists of two fine mesh wire cloths of deep
dish configuration installed in a carburetor mounting gasket.
The top (upstream) wire is coated with cadmium and the bottom
(downstream) wire cloth is coated with nickel. The object of
this devices is, through the alleged catalytic on the carbureted
mixture of gasoline and air, to precondition the mixture for more
efficient ignition, therby cleaning up existing carbon deposits in
the combustion chamber of the engine and reduce exhaust emission.
M.S.D. (Multiple Spark Discharge) IGNITION SYSTEM
This electronic ignition system provides a series of capacitive
discharge pulses in place of single discharge of conventional C.D.
or inductive systems. The vehicle's original contact breaker points
provide the timing signal.
pATCO POWER-PACK '
This device is a chemical fuel vaporizer which, according to
the manufacturer, increase gas mileage and power while reducing
pollution and maintenance due to carbon foul-up. It consists of
a 9-inch long cylindrical container, filled with an unknown chemical,
which mounts to a fender well or other suitable location in the
engine compartment. This unit ties into the PCV line by means of
& connecting hose and "T" fitting, which are provided in the Kit.
-------
-45-
PATON SYSTEM
This is a heated air bleed system. A small heat exchanger
is installed in the vehicle exhaust pipe. Air from the carburetor
air cleaner is drawn through this heat exchanger and into the PCV
line.
POLLUTION MASTER
This system consists of two parts. The"crankcase scavenger"
is a PCV valve replacement which acts as an air bleed. The "exhaust
scavenger" is a check valve which is a check valve which allows
secondary air to be drawn into the exhaust manifold by venturi
action.
SMOGMASTER
This device is a vacuum-operated air bleed valve which vents
filtered air into the PCV line. The device must be adjusted using-
an exhaust gas analyzer.
STP AIR COMPUTER
This device is a vacuum-operated air bleed valve. The valve
is operated by a signal from the distributor vacuum advance line.
A vacuum delay valve damps the action of the bleed valve, which
vents into the PCV line.
-------
-46-
V. CONCLUSIONS
V.A. Conclusions From The Inspection/Maintenance Study.
An obligatory I/M schedule is required for a HD vehicle
retrofit program to insure that:
1. devices are installed
2. they are properly installed
3. they are properly maintained.
I/M to assure that HD vehicles are properly tuned and main-
tained is in itself an effective control strategy. Averages over
181 pairs of tests indicate that tune up achieves:
1. 36% reduction in HC emissions
2. 33% reduction in CO emissions
3. almost 4% gain in fuel economy.
There is evidence that there are lower emissions after tune
up from vehicles that are routinely well maintained than from
vehicles that are not. The gain in fuel economy represents a
savings of $8.80 for every 1,000 miles driven if gasoline is $1.30
a gallon.
Data collected in the study can provide valuable information
on relations between vehicle condition and pollutant emissions.
It is hoped that investigators concerned with these topics will
take advantage of the DATA TAPE discussed in Appendix I and the
test data printouts, in Appendix III.
V.B. Conclusions From The Retrofit Study.
Catalytic And Non-Catalytic Controls.
Non-catalytic devices can achieve considerable reductions
in pollutant emissions. However, extensive studies at the Mobile
Systems Laboratory show that catalytic converters have greater
promise for HD retrofit than non-catalytic devices.
Catalytic converters are discussed in a separate report. (6)
Durability Of Non-Catalytic Devices.
In order to collect data on retrofitted vehicles in in-service
condition the vehicles were deliberately not tuned up when they
were periodically retested. This accounts for the erratic variations
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in emissions from test to test as seen, for example, in the
plots of retrofit measurements in Appendix II. Since these
variations mask any gradual deterioration in the performance
of the retrofit devices the goal of determining the deterioration
in performance of the devices could not be met.
Even if the vehicles were tuned before retesting it is
unlikely that variations would be reduced sufficiently to
allow deterioration to be determined because device deterioration
would still be masked by vehicle deterioration. Vehicle
deterioration depends on the quality of maintenance received
by the vehicle. Maintenance quality varies from fleet to
fleet and can vary from vehicle to vehicle within a fleet.
The only way to control this factor is for the testing laboratory
to assume responsibility for all maintenance and repairs on
the vehicles. This would be impractical for in-service fleets.
It appears that deterioration in emissions reductions
and fuel economy, if any, of non-catalytic devices cannot be
determined by periodic testing of in-service vehicles.
The durability of the devices tested in the study appeared '
good. No evidence of physical deterioration was observed in
properly installed devices.
y.B.I. Conclusions On EGR Devices.
EGR devices are effective in reducing CO and NOX emissions.
Test results also indicated a slight improvement in fuel economy
and little change in HC emissions.
The devices were no longer available as HD retrofits during
the study. However, EGR devices were still used as original
equipment on autos and the state of the art has progressed since
the tests made in the study.
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Experience with installing EGR retrofits on HD vehicles
showed it to be a more costly and time consuming process than
retrofitting autos. Unless EGR devices are properly maintained
and adjusted they have a potential for causing drivability
programs in HD vehicles. These two factors weight against EGR
devices as first choice for a HD retrofit program.
y.B.2 Conclusions On Air Bleed Devices
The test results on air bleed devices indicate they are
effective CO controls, relatively ineffective HC controls and
slightly increase NOX emissions. They produce only a slight
gain in fuel economy, a disappointing result since the ADAKS
device was sold as a fuel savings retrofit for autos.
Installation was simple and no maintenance or drivability
problems were found. Within its limitations the air bleed might
£e considered as part of a retrofit program for older HD vehicles.
for newer vehicles improvements in original equipments carburetors
and other changes have already accomplished most of the improve-
jnent that could be expected from an air bleed retrofit.
y.B.3 Conclusions On Lean Mixture Carburetors.
The wide range of results from carburetor retrofit shown in
rpable IV-K requires explanation. Retrofit produced large decreases
in HC, CO and NOX emissions in vehicles 4177 and 4633 yet produced
large increases in HC and NOX emissions in vehicle 19899. The
Batter result seem to contradict the general observation that
carburetor retrofit is an effective emissions control method.
It is probable that the best results in the Table IV-K are
typical of the improvements obtainable with lean mixture carburetor
retrofit. Some of the increases in emissions observed in the
*rable undoubtedly result from the procedure used to adjust the
-retrofitted carburetors. These were adjusted to minimize emissions
at idle and fast idle. However, this does not guarantee that
tjie mixture is not too rich under the load conditions of the
Driving cycle.
Another probable reason for high emissions was the lack of
Aata on matching retrofit carburetors to HD engines. Matching
no problem where a "California" carburetor existed to match
engine that had been in production for a number of years.
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However, matching old engines for which improved replacement
carburetors were not available involved subjective judgements.
This might have resulted in a mismatch over part of the engines1
operating range.
The data indicates that lean mixture carburetors are
effective retrofit devices for older, rich mixture HD engines.
On newer vehicles the effect of carburetor retrofit would be
much less pronounced. The variability in effectiveness in
Deducing emissions make the universal use of lean carburetor
j-etrofit inadvisable except as part of a more comprehensive
control strategy.
A lean carburetor retrofit program would require a prelim-
inary study on criteria for selecting and adjusting the carbur-
etors .
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VI. REFERENCES
(1) New York City Metropolitan Area Air Quality Implementation
Plan - Transportation Controls, New York State Dept. of
Environmental Conservation, April 1973.
(2) Norman Friberg, An Evaluation Of Retrofit Devices For Heavy
Duty Vehicles, Final Report, Federal Environmental Agency
Grant S802909. April, 1978.
(3) The Clayton Keymode Test is a product of the Clayton Manu-
facturing Co., El Monte California
(4) Norman H. Nie et. al., SPSS Statistical Package For The
Social Sciences/ 2'nd edition/ McGraw Hill Book Co., New York.
1975
I t
(5) Robert W. Olsen and K.J. Springer/ "Exhaust Emissions from
Heavy Duty Vehicles", Presented at the Nat. Combined Fuels and
Lubricants and Transportation Meetings, Huston/ Texas. Nov 4-7,
1969. SAE No. 690764
(6) Laslo Goldberger/"Heavy-Duty Vehicle Catalyst Retrofit Certi-
fication" New York City Department of Environmental Protection,
Mobile Systems. December, 1976.
(7) Covington/ J.P. "Moderning the Fixed-Venturi Carburetor" article
in Automotive Engineering/^ July 1974
(8) Bulletin of the California Air Resources Board. May, 1973
This light duty vehicle driving cycle is described in the
Federal Register/ Part II,Vol.35 pp.17311/ 17312. November 10, 1970
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing/
1. REPORT NO. 2
EPA 902/4-81-001 A
4. TITLE AND SUBTITLE
Study Of Control Strategies For In-Use Heavy
Duty Vehicles. Final Report
7. AUTHORJSJ
John J. Pinto
9. PERFORMING ORGANIZATION NAME AND ADDRESS
NYC Department of Environmental Protection
Mobile Systems Division
75 Frost Street
Brooklyn , N . Y . 112 11
12. SPONSORING AGENCY NAME AND ADDRESS
United States Enviromental Protection Agency
Region II
26 Federal Plaza
New York, N.Y.10278
15. SUPPLEMENTARY NOTES
Ifi A RKTRAOT ~
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
Approved 5/81
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPOR1
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
Contract 68-01-4319
13. TYPE OF REPORT AND PERIOD COVED
Final
14. SPONSORING AGENCY CODE
To collect baseline information for heavy duty vehicle
Inspection/Maintenance programs, a large fleet of in-service
gasoline powered vehicles were chassis dynometer tested for
HC, CO and NOx emissions and fuel economy in as-received condition
and again after being tuned .to their manufacturers' specifications.
Computer analysis of the changes produced by tuning are presented
and discussed. x
To investigate the suitability of commercially available non-
catalytic emissions control devices for heavy-duty-vehicle retrofit
programs over fifteen such devices were screened. Exhaust gas
recirculation devices, air bleeds and lean mixture carburetors were
selected as promising candidates for retrofitting. These devices
were installed on in-service heavy duty vehicles. Emissions and
fuel economy were tested immediately after installation. The
vehicles were recalled and retested periodically to monitor changes
in devices effectiveness with use and time. Test results are
evaluated to determine in applicability of the devices to a heavy dm
retrofit program. J
17' KEY WORDS AND DOCUMENT ANALYSIS ~~
a- DESCRIPTORS
IB. DISTRIBUTION STATEMENT ~~
b.lDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report}
20. SECURITY CLASS {This page}
c. COSATI Field/Gio»
21. NO. OF PAGES
81
22. PRJCE
EPA Form 2220.) (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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