HIGH ALTITUDE VEHICULAR EMISSION CONTROL PROGRAM
VOLUME VII -EXPERIMENTAL CHARACTERIZATION OF
VEHICULAR EMISSION AND ENGINE DETERIORATION
¦'V-V ./"'w
PREPARED FOR:
STATE OF COLORADO
DEPARTMENT OF HEALTH
DENVER, COLORADO 80220
ENVIRONMENTAL PROTECTION AGENCY
REGION VIII
DENVER, COLORADO 80203
-------
(1$
q20\
HIGH ALTITUDE VEHICULAR EMISSION CONTROL PROGRAM
VOLUME VII.EXPERIMENTAL CHARACTERIZATION OF
VEHICULAR EMISSION AND ENGINE DETERIORATION
PREPARED FOR:
STATE OF COLORADO ENVIRONMENTAL PROTECTION AGENCY
DEPARTMENT OF HEALTH REGION VIII
DENVER, COLORADO 80220 DENVER, COLORADO 80203
-------
DISCLAIMER
This report was developed for the Environmental Protection Agency and
the State of Colorado by TRW using data supplied by ATL under contract
numbers 68-02-1385 and C290526. The contents of this report are reproduced
herein as received from the contractor. The opinions, findings, and con-
clusions are those of TRW and are not necessarily those of the sponsoring
agencies. Mention of company or product names does not constitute endorse-
ment by either the Environmental Protection Agency or the State of Colorado.
The results and conclusions presented are based on the data developed
from the deterioration .test program conducted by Automotive Testing Lab-
oratories. The extent to which these data are not representative of the
vehicle population in the Denver area, however, could have a significant
impact on the resultant conclusions and recommendations.
-------
PREFACE
This report, "High Altitude Vehicular Emission Control Program,"
consists of seven volumes. Listed in the following are the subtitles
given for each volume:
• Volume I - Executive Summary, Final Report, January
1974.
• Volume II - Experimental Characterization of Idle
Inspection, Exhaust Control Retrofit and Mandatory
Engine Maintenance, Final Report, December, 1973.
t Volume III - Impact of Altitude on Vehicular Exhaust
Emissions, Final Report, December, 1973.
• Volume IV - Analysis of Experimental Results, Final
Report, December, 1973.
• Volume V - Development of Techniques, Criteria and
Standards to Implement a Vehicle Inspection,
Maintenance and Modification Program, Final Report
December, 1973.
• Volume VI - The Data Base, Final Report, June, 1975.
e Volume VII - Experimental Characterization of Vehicular
Emission and Engine Deterioration, Final Report, April,
1976.
The first volume summarizes the general objectives, approach and
results of the study. The second volume presents a detailed description
of the experimental programs conducted to define the data base. Volume
III reports the methods and analysis used in developing the basic
relationships between mass emissions and altitude. A quantitative
analysis of the results from the experimental program is presented in
Volume IV. The fifth volume provides an analysis of the techniques
and criteria required in establishing a vehicle emission control program
for the Denver area. The actual data base developed from the experimental
-------
program is given in Volume VI. Lastly, this volume reports the results
of the six and twelve month deterioration program.
The work presented herein is the product of a joint effort by two con-
sulting firms. Automotive Testing Laboratories (ATL) was responsible for
the design and implementation of the basic experiments. TRW provided the
data management and analysis of the experimental results.
-------
TABLE OF CONTENTS
Page
1.0 SUMMARY AND CONCLUSIONS 1
2.0 INTRODUCTION 3
3.0 PROCEDURES DEVELOPMENT 4
3.1 Program Design 4'
3.2 Test Vehicles 7
3.3 Laboratory Testing and Evaluation ; . 8
3.4 Data Processing and Management 11
4.0 EXPERIMENTAL RESULTS 14
4.1 Unauthorized Maintenance 14
4.2 Sample Attrition 16
4.3 Test Sample Mileage . . . 17
4.4 Vehicle Owner Behavior 18
4.5 Impact of Deterioration 19
APPENDIX A Denver Deterioration Study Odometer Readings ... A-l
APPENDIX B Denver Deterioration Data B-l
-------
1.0 SUMMARY AND CONCLUSIONS
This report highlights the findings of the high altitude emission
deterioration program. It represents an update of yolume VII, originally
issued as an "Interim Report" in July 1974. Data from the planned one
year program is now available and has been analyzed to derive the results
presented herein. The format duplicates that of the original volume and
where it is deemed useful, data contained in the six .month report has
been repeated in this update.
• Unauthorized Maintenance: One out of four vehicle owners re-
turning for retest at the six month point of the program violated
the no servicing agreement, having adjusted or replaced one or
more of the fourteen engine components known to affect emission
performance. During the second six months, no restrictions were
placed on owner servicing; at the twelve month test point three
out of four owners had serviced one or more of the controlled
items. The net effect of this uncontrolled service is to severely
limit the accuracy of calculated deterioration rates.
• Deterioration Rates:
Six months:
Reductions in hydrocarbons and carbon monoxide resulting
from initial maintenance procedures were cancelled by
engine deterioration after six months. Calculated rates
for 165 vehicles:
Hydrocarbons 0.7 gm/mile/1000 miles
Carbon Monoxide 1.0 gm/mile/1000 miles
(The unauthorized maintenance detected after six months
tends to cause underestimation of the deterioration
rates).
-------
Twelve months:
Owner servicing during the second six months of the study
completely swamped the deterioration effects. Hydrocarbon
and carbon monoxide emissions were found to be lower at
the twelve month point than had been measured at six months.
• Sample Attrition: At the six month point two thirds of the
original 250 vehicle test fleet were available for retest. At
the end of one year the number of vehicles available for retest
was 109 of the original 250 (44%). Vehicle attrition was approx-
imately evenly distributed with model year distributions holding
within a few percentage points of the initial values throughout
the test program.
• Vehicle Mileage: Vehicle miles travelled during each of the two
six month segments was found to be well below Colorado Department
of Health estimates for average vehicle use. Initially, it was
thought that the fuel shortage experienced during the first six
months of the study was responsible for the low mileage. The
continuing low vehicle mileage throughout the year long program
suggests that the vehicle owner volunteers were not typical of
the Denver driving public in their driving patterns; perhaps the
sample had a disproportionately low number of commuters in its
make -up.
• Mandatory vs. Idle Inspection: Neither mode of vehicle treatment
was found to give significantly greater emission reductions at
the start of the program. Also, at the end of six months,
deterioration rates were nearly identical for both fleets,
indicating that the more expensive mandatory maintenance treatment
is unjustified. The loss of emission reductions at six months
for either treatment indicates the need for a semi-annual in-
spection/maintenance program to achieve and sustain emission
reductions.
-------
2.0 INTRODUCTION
A basic unknown in evaluating the cost-effectiveness of vehicular
inspection/maintenance is the extent and characteristics of emission
deterioration. Studies conducted by TRW have shown that emission
deterioration can have a substantial impact on the effectiveness of
the selected procedure (e.g., idle inspection).* In an attempt to
assess the potential impact of emission deterioration at altitude, an
experimental test program was undertaken using 250 vehicles. This pro-
ject was designed to characterize emission deterioration and engine
degradation for vehicles operating in the greater Denver area. The
project, involving the re-test of vehicles available at the conclusion
of two consecutive six month intervals recently was completed.
This report presents an analysis of the results from the twelve
month engine deterioration and degradation study.
The primary objective of this study was to develop emission
deterioration factors which are to be utilized to evaluate the long
term benefits of a mandatory inspection and maintenance program as a
strategy for reducing vehicular emissions. A secondary object was
to determine the extent of owner tampering, including its impact upon
the effectiveness of an inspection/maintenance program, and to determine
possible legislative requirements to maintain overall effectiveness of a
mandatory program.
* TRW, CAPE-13-68 Research Program (1972).
-------
3.0 PROCEDURES DEVELOPMENT
3.1 PROGRAM DESIGN
The program was designed to utilize a preconditioned and pretested
sample of vehicles from which various data, pertinent to program objectives,
could be obtained.
A sample of three-hundred 1964 through 1973 model-year vehicles,
selected to represent that segment of the Colorado light-duty vehicle
(under 6000 lbs GVW) population, was used initially to evaluate idle
inspection and maintenance, emission control retrofit and mandatory
engine maintenance. This segment represented about 90% of the light-
duty vehicle population. All vehicles in the sample were initially
subjected to inspection and maintenance. Idle emission inspections
were performed at ten selected state licensed motor vehicle safety
inspection stations. Station personnel were trained in advance and
were required to perform inspection and maintenance of vehicles in
accordance with specific procedures. All yehicles were laboratory
I
tested in the as-received condition before delivery to the stations.
Vehicles which failed station inspection and were subsequently repaired
were re-tested by laboratory procedures to determine the effectiveness
of station performance. A segment of the vehicle sample was then
utilized to evaluate emission control retrofit and modified tune-up
specifications.*
* A more complete description of the basic test procedures can be
found in Volume II of this report.
-------
Although three-hundred vehicles comprised the initial sample, the
potential size of the sample available for re-test was reduced to about
two-hundred and fifty vehicles.* This reduction, numbering about fifty
vehicles, came about as a result of an initial loss of several vehicles
which had been tested and released to owners prior to start-up of the
deterioration study. A number of other vehicles comprising the initial
sample were determined to be unsuitable for deterioration study purposes
for various other reasons.
During the time interval following initial testing, vehicles com-
prising the test sample were presumably operated in a typical manner
although several existing factors undoubtedly had some impact on mid-
point results. The interval (August, 1973 through May, 1974), spanned
the winter season with its typically cold weather and presumably had
a direct effect on engine warm-up characteristics, mileage accumulation
and maintenance requirements. Additionally, the fuel crisis and attendant
factors were predominant throughout much of the study interval and are
believed to have potentially biasing effects on 'study" results"by altering
mileage accumulation patterns, fuel preference and overall vehicle useage.
The effects of these variables are virtually impossible to evaluate. In
any case, the project proceeded according to design.
In planning for the interval which followed initial testing, pro-
cedures for handling test vehicles exhibiting undesirable operating
characteristics or component failure were devised. A maintenance
* Of the original 250 vehicles, 150 were assigned to the idle inspection
fleet and 100 to the mandatory maintenance fleet. These initial group
sizes were reduced (the results of attrition) to 87 and 78 vehicles,
respectively.
-------
committment was established and communicated to the vehicle owner; a
vehicle prematurely returned to the laboratory for repair work was sub-
jected to an on-the-spot inspection to establish the validity of a re-
quest for repair. In certain situations, owner dissatisfaction with some
aspect of vehicle performance proved to be unfounded. In other situations,
a legitimate requirement for maintenance did in fact exist. In the
latter case, a loan car was issued and the test vehicle was retained
for further testing amd maintenance. In this case, a series of tests
identical to those performed initially was conducted, repairs to the
vehicle were completed and the vehicle was returned to its owner.
Data developed as a result of these procedures were retained for sub-
sequent processing and reporting.
As reported earlier, two hundred and fifty vehicles of the
original sample were judged suitable for retest. It was originally
anticipated that a significant number of vehicles would be lost to
the program for various reasons including transfer of ownership,
owner relocation, accidents or negative owner reaction including loss of
interest. In this respect an attrition rate of 40 percent was allowed.
After the nominal interval of six months had elapsed, vehicles
were recalled for deterioration and degradation testing. An attempt
to maintain an initial tolerance of 180 + 5 days proved to be imprac-
tical and the tolerance was subsequently relaxed to 180 — 10 days to
maintain a high retest rate.
At the appropriate time, one or more attempts to contact owners
whose vehicles qualified for retest were made. As anticipated, a
significant number of owners had moved outside the area, had sold the
-------
test vehicles, had expressed dissatisfaction with some aspect of the
program or had simply become disinterested. On the other hand, a
significant number of vehicles (165) remained available for retest.
Testing procedures identical to those performed initially were then
conducted. At test completion engine adjustment seals and identification
marks on emission related components were inspected and the incoming
status of each adjustment and component part was recorded. Data were
then processed and compiled.
Throughout the retest phase of the program, laboratory instrumentation
and equipment calibration and operating procedures were maintained in
accordance with standards applied in the initial program. Quality
control tolerances were similarly maintained and procedures relating to
data auditing were applied.
At the conclusion of the six month tests, the seals and identifica-
tion marks were restored where tampering had been detected. Vehicles
were returned to their owners for a second six month use period identical
to the first with one exception: no maintenance agreement was established
with the owner. In general, they were not aware that they would be invited
back for retest at the end of the next six month period.
3.2 TEST VEHICLES
Three hundred vehicles were initially selected and utilized to rep-
resent the 1964 through 1973 Colorado motor vehicle population. Approx-
imately two hundred and fifty were prepared for the deterioration study
phase. As anticipated, a significant level of attrition occurred during
-------
the six month period and one-hundred and sixty-five vehicles were
actually submitted for retest. After 12 months, only 109 vehicles remained
in the test sample.
3.2.1 Vehicle Sample Composition
Table 1 shows the distribution of vehicles at the program start
and at the six and twelve month retest points. Distribution by model
year remained fairly stable throughout the program as shown by the
"percent of sample" figures. However, in many instances some make-model
year combinations were drastically reduced or eliminated by the sample
dropouts at either the six or twelve month points.
3.2.2 Vehicle Preparation and Handling
Upon receipt of the vehicle for retest, an inspection of the
vehicle exterior, interior and exhaust system was performed to deter-
mine incoming status. A loan car was issued to replace the test
vehicle and the necessary vehicle agreement forms were completed. The
vehicle was then moved to the laboratory for temperature soaking
prior to emission testing and engine inspection.
After a minimum soak period of twelve hours, the vehicle fuel
supply system was disconnected and reconnected to a laboratory fuel
supply system. A batch of summer-grade fuel, utilized for initial
testing had been retained and was used to perform the retests. Emission
tests were then performed, the vehicle was relocated to another area
in the laboratory and an inspection of engine components and adjustments
was completed. The vehicle was then returned to its owner.
3.3 LABORATORY TESTING AND EVALUATION
Procedures employed for retest were identical to those applied
initially.
-------
12
1
0
1
2
1
1
1
0
1
0
0
0
0
0
0
0
8
7
Table 3-1. Sample Distribution
1973 1972 1971 1970 1969 1968 1967 1966
0
6
12
0
6
12
0
6
12
0
6
12
0
6
12
0
6
12
0
6
12
0
6
12
1
0
0
1
1
0
1
1
0
1
1
1
1
0
0
1
1
0
1
0
0
1
1
1
1
0
0
1
U
0
1
1
1
1
0
0
2
0
0
2
2
0
2
1
1
2
0
0
1
0
0
1
C
0
1
0
0
1
1
1
1
0
0
1
0
0
1
0
0
1
0
0
7
6
3
7
4
3
7
3
3
6
3
2
6
2
1
7
2
1
6
5
3
7
5
3
1
0
0
1
1
1
1
1
1
1
1
0
1
0
0
1
0
0
1
1
1
1
0
0
2
1
0
2
1
1
2
0
0
2
1
1
2
1
1
2
1
1
1
1
0
2
1
1
8
4
2
8
4
3
9
6
5
8
3
2
6
2
2
5
4
3
6
6
4
7
5
4
1
0
0
1
1
1
1
0
0
1
0
0
1
1
1
1
1
0
2
1
1
1
0
0
1
1
1
1
0
0
1
0
0
2
1
1
2
0
0
2
1
0
2
1
0
2
1
1
3
1
1
3
3
1
3-
1
1
2
2
2
2
2
1
2
1
1
2
1
1
2
1
1
1
1
1
1
1
0
2
1
0
2
1
0
2
1
0
3
0
0
3
3
3
2
2
1
3
0
0
3
1
1
2
1
0
2
2
1
2
0
0
2
2
7
2
0
0
2
2
1
0
0
0
0
C
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
c
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
0
0
1
c
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
33
16
10
33
IE
11
35
17
13
30
17
11
29
10
7
30
15
7
29
20
14
30
18
13
n
10
9
11
11
10
12
10
12
10
10
10
10
6
6
10
9
6
10
12
13
10
11
12
250
165
-------
3.3.1 Exhaust Emission Testing Procedures
Laboratory standard exhaust emission tests were performed in
accordance with procedures outlined in Federal Register,Volume 3B,
Number 124, Part III, dated June 28, 1973. Standard tests were pre-
ceeded by a minimum 12 hour temperature soak at laboratory ambient
conditions (68° F to 72° F).
Loaded mode tests were performed in accordance with procedures
outlined by Clayton Manufacturing Company of El Monte, California.
Loaded mode testing and the resultant data have no direct bearing on the
objectives of this phase of the study but were included in the test
procedure merely to expand the data base.
Idle emission testing was performed in conjunction with loaded
mode testing. Emission samples were taken at no load conditions of
curb idle (drive gear for automatic transmission equipped vehicles) and
2500 engine rpm. Instrumentation and operating procedures were identical
to those employed during the initial phase of testing. Both laboratory and
garage-type inspection equipment (listed in Table 5 of Volume II) were
employed.
Instrument and equipment calibrations established in the initial
testing phase were maintained throughout the retest interval. Analytical
system calibrations were established using an inventory of EPA named
gases. Flow calibration of the CVS was verified using the laminar flow
element with calibration traceable to the National Bureau of Standards.
Dynamometer calibrations were established and verified on a regular
basis using the coast-down technique. In addition, propane recovery
tests, NO converter efficiency checks and analytical system leak checks
were performed on a daily basis.
-------
3.3.2 Engine Diagnostic Procedures
Diagnoses of engine conditions were performed at two points in the
overall vehicle procedure. During loaded mode operations on the chassis
dynamometer the laboratory analytical system recorders were operational
for a period of about one minute. Ducing this interval and during
periods of speed changes, emission traces were observed for an indication
of malfunction evidenced by abnormally high hydrocarbon (HC) or carbon
monoxide (CO) levels and these observations were recorded. The HC trace
also provided an indication of ignition system mis-fire.
Oxides of nitrogen (NO ) emission controls on applicable vehicles
A
were inspected for proper operation during loaded mode testing. A fully
operational system was indicated by the absence of vacuum to the distribu-
tor at high cruise conditions.
The second point at which diagnostic procedures were applied was
immediately after dynamometer tests were completed. The vehicle was
removed from the dyanmometer area and a more extensive diagnostic pro-
cedure was applied. Concurrently, the inspection to determine the extent
of tampering and alteration or replacement of parts was performed.
3.4 DATA PROCESSING AND MANAGEMENT
The combination of a large data base, and the necessity of a
series of complex operations involved in the analysis, necessitated
the use of a computerized data management system.
The data collected from the deterioration experiment has been
stored as a working file on the CDC 6500 disk pack. More permanent
copies of the data base are also stored on a magnetic tape and on
-------
card files. Extensive computer software was utilized in managing and
processing the data. The following data management activities were
performed by TRW:
e retrieval and sorting of data
e development of graphic presentations
• statistical analysis.
A brief description of each of these data management functions is
presented in the subsequent paragraphs.
Retrieval and Sorting of Test Data
The principal data handling program in the data management
system, DETER, serves as the basic interface between the data base
and other software. This program retrieves the selected data from
disk storage and sorts it by a number of classification'^terns. The
data can be culled in the following ways:
e CVS emissions
0 Loaded modes
• Engine parameters
o Vehicle characteristics
1) the total population
2) sort by age group
3) sort by manufacturer
4) sort by make, within a manufacturer
5) sort by engine size group
6) sort by weight group
7) sort by PASS/FAIL at idle inspection
Statistical Analysis
Two main statistical packages were used in processing the data
relevant to the engine deterioration study.
-------
The data handling program DETER had basic statistical capabilities
built into it. It computed means, standard deviations, T-scores, and
CVS emission deterioration factors.
The DETER program also was used to create an input file for the
other statistical applications program (TSTAGE). The TSTAGE program
performed ordinary least squares regressions. Equations were derived for
the deterioration of the three CVS mass emissions (HC, CO, N0X) as
functions of the odometer readings. Dummy variables were exploited to
yield independent equations for the different sort groups (i.e., age
group).
-------
4.0 EXPERIMENTAL RESULTS
This section presents the experimental results of the deterioration
program. The results of the six month program have been updated to include
the full year of test data. In addition, some of the concerns expressed
in the interim report are explored in further detail.
4.1 UNAUTHORIZED MAINTENANCE
During the first six month period, vehicle owners were specifically
requested to refrain from servicing emission affecting parts and adjust-
ments during the period between inspections. Incentives were supplied in
the form of a cash payment and the offer of free service should mainten-
ance be necessary before the six month point.
The object of the six month experiment was to measure the change of
vehicle emissions in the absence of corrective maintenance. The results,
as reported previously for six months, were disappointing. Twenty-five
per cent of the vehicles available for retest showed evidence of mainten-
ance on one or more of the fourteen controlled items (parts or adjustments).
Faced with this relatively large rate of unauthorized maintenance, the
experimenters were presented with a serious dilemma: Determine
the deterioration of the vehicle sample when one fourth of the sample has
received some form of corrective maintenance.
In the interim report, the approach taken was to evaluate the extent
of fleet deterioration with and without the vehicles that received unautho-
rized maintenance. The results in terms of vehicle emissions were reported
to be not significantly different either way. Within the context of the
data available, this was as far as the investigators could go in assessing
-------
the effect of unauthorized maintenance. Left unanswered were several
specific questions which must be addressed before a definite statement
can be made on the true effect of owner maintenance.
1. Why was service performed at the owner's expense when1specific
arrangements had been made, including the offer of free service?
Obviously, 25% of the vehicle owners were not impressed sufficiently
with the incentives in the program to preclude having service performed
outside the program. At this point we can only guess the motivation
for their actions, but must face the unfortunate possibility that
service was performed because the owners became dissatisfied with
their car's performance. A missing engine, poor acceleration, stalling,
hard starting, or any number of other defects may have convinced the
owners immediate service was needed, and therefore they opted not to
return to the test laboratory but rather to have the vehicle attended
to locally. If this was the case, it is reasonable to assume that the
vehicle defect(s) also resulted in changes in emission performance
and would impact the results of the experiment.
2. What were the emissions of those vehicles receiving unauthorized
service just before maintenance was performed?
This data cannot be determined for this experiment since the main-
tenance was uncontrolled. Without this data the experiment has
received a critical setback. Possibly for a large percentage of
serviced vehicles, the emission performance was unchanged by the
unauthorized maintenance, but considering the program incentives and
the decision that the controlled items normally do affect emission
performance, it seems probable that emissions did increase for these
vehicles and that the unauthorized service had the effect of correct-
ing higher emissions. The missing data then represents a serious
(perhaps insurmountable) obstacle in determining correct deteriora-
tion rates for the Denver vehicle population from the available data.
3. What are the implications of the unauthorized maintenance detected in
this study with regards to the enforcement of controlled inspection
maintenance?
The message to be learned from the unauthorized maintenance check is
reasonably clear: A significant portion of the vehicles will be
maintained by their owners outside any mandatory inspection program.
Even when the alternatve of free service is offered as it was in this
study, vehicle owners will spend their own money to maintain their
cars. Furthermore, based on the analysis of the data, the service
that is done will not degrade emission performance. On the contrary,
it would appear more likely to reduce pollutants.
-------
4.2 SAMPLE ATTRITION
Vehicle availability at the six and twelve month points was expected
to be reduced relative to the size of the starting sample and the actual
results match expected attrition rates (as was noted in the interim report).
The attrition in the sample leads to another disquieting question: Exactly
what happened to the vehicles and their owners to cause them to be unavail-
able at the twelve or six month test points?
No survey was planned or taken, so it is necessary once again to guess
the answer to the posed question. There are two possibilities that have
serious consequences for the deterioration analysis.
There is the possibility that owners of vehicles not available
for retest had unauthorized maintenance performed and were embarassed
to reappear with their serviced cars. For dropouts at the six month point
due to this possibility, the number of vehicles receiving unauthorized
maintenance could be considerably larger than the 25% detected and thereby
compound the problem discussed above.
Another possible and perhaps more probable reason for vehicle non-
availability at either the six month or twelve month retest points is the
change of ownership during the intervals. No provisions were made to track
down new owners of the vehicles in such cases so that each such change
automatically caused the loss of the vehicle to the test program. Vehicle
ownership changes frequently can be traced to owner dissatisfaction with
the performance of their vehicles. The prospect of large repair bills can,
-------
and often does,lead to consideration of a new or newer car. If a large
number of the 141 out of 250 original test vehicles not available for
retest did in fact fit this category, then there is one more reason to be
concerned about the data base.
Whatever the reasons for the large sample attrition, the data base
has been severly impacted by the loss of so many vehicles, unless it can
be shown that the lost vehicles are randomly distributed. The two possi-
bilities explored above are serious because they tend to discount random-
ness and,in fact, suggest a relationship between a "no-show" and the emis-
sion performance of the affected vehicles.
4.3 TEST SAMPLE MILEAGE
In examining the test sample for possible weaknesses, the interim
report pointed out that vehicle mileage for the first six months was rela-
tively low. It was thought that the fuel shortage and the attendant
gasoline price rise combined to limit vehicle use during the period. The
results for the second six month period show continued low mileage accumula-
tion. The mileage figures are so low that it is necessary to question the make-
up of the test sample as far as vehicle use patterns are concerned. Appendix A
summarizes the mileage figures for all vehicles throughout the program;
the numbers for a large percentage of the vehicles are below typical mile-
age figures supplied by the Colorado Department of Health.
The participants in the test program were volunteers from the Denver
area selected mainly to form a fleet typical of the Denver vehicle popula-
tion by make and model year. It is possible that in choosing the parti-
cipants with the vehicle owned as the criterion may have resulted in a
sample lacking in drivers typical of the population. For example, the
-------
low mileage figures may indicate a low participation by drivers who daily
commute to work. This would explain the low mileage figures throughout
the one year interval of the program rather than assuming gasoline short-
ages/prices were still dominant. In any case, low mileage must be added
to the list of problems that cropped up during the deterioration study.
4.4 VEHICLE OWNER BEHAVIOR
The preceding sections deal with some important negative aspects of
the deterioration study. Now we shall examine some of the useful results
that can be derived in spite of the limitations in achieving the originally
planned program results.
4.4.1 Owner Tampering
The high occurrence of unauthorized maintenance in an al1-volunteer
program with built-in incentives designed to prevent such action provides
an insight into the administration of an inspection/maintenance program.
There is the concern that an inspection/maintenance program may fail to
achieve its goals of reducing vehicle emissions because of owner tampering
between the scheduled inspections. The six month results of the deterio-
ii
ration study indicate that tampering can be expected but rather than de-
feating the benefits of inspection/maintenance, the unauthorized service
resulted in no significant increase in emissions when compared to the
unserviced cars. Actually, a more reasonable conclusion is that the
service performed by the owners preserved or even restored low emission
performance to their vehicles.
-------
4.4.2 Maintenance Patterns
In the second six month interval of the experiment, vehicle owners
were generally unaware that they would be called back for retest.
Obviously, the restrictions on service were automatically lifted and the
vehicle owners were free to have any work done they cared to. The coded
marking and part identification procedure instituted for the first six
months was, however, repeated at the start of the second six months. On
recall, laboratory inspectors re-inventoried the controlled items not
to detect unauthorized service but to record owner maintenance patterns.
Table 4-1 summarizes the results of the vehicle owner servicing surveys.
With owner-initiated maintenance detected in over 75% of the vehicles
checked after the second six month period, maintenance patterns for emis-
sion related parts and adjustments are encouraging. In the absence of
controls, the results indicate that vehicle owners will not neglect the
servicing of critical components, thereby preserving low emission perform-
ance on their cars. The willingness of vehicle owners to take their vehicles
in for service coupled with a service establishment skilled in restoring
or maintaining low emissions offers a viable means of achieving pollution
control.
4.5 IMPACT OF DETERIORATION
Note:
Due to the problems relating to the data base cited above, only a
limited updating of the analysis contained in the six month interim report
has been performed.
-------
Table 4-1. Summary of Vehicle Owner Maintenance
6 months^-
Idl
Monitored Item
Ignition wires
Coil
Spark plugs
Air filter
Fuel mixture screws
Idle adjust, screws
Choke setting
Dist. adj. screw
Points adj. screw
Condenser
Rotor
Distributor cap
PCV
Number
2
0
5
10
0
2
2
4
3
3
2
2
1
%
2
0
6
11
0
2
2
5
3
3
2
2
1
e Fleet
12 months2
Mandatory Maintenance Fleet
6 months!
Number
10
4
25
26
6
11
6
8
17
14
13
9
3
%
18
7
45
47
11
20
11
15
31
25
24
16
5
12 months^
Number
%
Number
%
2
3
7
13
1
1
2
4
3
4
22
41
5
6
31
57
2
3
7
13
2
3
12
23
2
3
7
13
3
4
6
11
4
5
22
41
3
4
20
37
2
3
18
33
4
5
10
19
2
3
4
7
Sample Size
87
55
78
54
^Vehicle owners requested not to perform maintenance to the items listed.
-------
4.5.1 Idle Inspection and Maintenance
The idle inspection and maintenance procedure, as detailed in Volume
IV, consisted of an initial examination of the loaded modes idle HC and
idle CO. If the vehicle conformed to the prescribed standards (see Table
4-2) it was left untouched, however, if it failed, a systematic program
of engine maintenance was performed.
Table 4-2. Idle Inspection Pass/Fall Criteria
Criteria
Measurement Pre-Controlled Controlled
Idle HC 800 ppm 330 ppm
Idle CO 6% 4%
A brief review of the CVS mass emission results for the idle inspection
and maintenance program is given in Table 4-3 for the vehicles* remaining
in the idle test fleet at the end of six months.
Table 4-3. Idle Inspection: CVS Emissions for Vehicles Remaining at
6 Months
Pre-Maintenance
Post-Mai ntenance
After 6
Months
Deterioration Rate
Mean
Std.Dev
Mean
Std.Dev
Mean
Std.Dev
(Gm/mi/1000 mi)
Pollutant (Gm/mi)
(Gm/mi)
(Gm/mi)
HC 3.18
5.28
6.99
3.57
11.09
14.11
0.50
O
O
00
o
51.57
101.12
47.37
112.51
63.96
0.86
i!0x 2.64
1.42
2.60
1.41
2.37
1.33
0.00
* Individual vehicle data is summarized in Appendix B.
-------
Table 4-4 repeats the calculations for just those vehicles remaining at
the end of 12 months.
Table 4-4. Idle Inspection: CVS Emissions for Vehicles Remaining at
12 Months
Pollutant
HC
CO
NO.
Pre-Maintenance Post-Maintenance After 12 Months Deterioration Rate
Mean Std.Dev. Mean Std.Dev. Mean Std.Dev. "(Gm/mi/IOOO mi)
(Gm/trn) (Gm/mi) (Gm/mi)
8.33 6.33 6.80 3.92 7.57 4.85 0 09
109.76 56.54 97.19 52.02 100.57 54.96 0 41
2-64 1-42 2.66 1.44 2.51 1.35 -0 02
4.5.2 Mandatory Engine Maintenance
Vehicles in this fleet underwent engine maintenance procedures as
detailed in Volume IV of this series. The pre- and post-deterioration
results for those vehicles remaining at the end of six months are summar-
ized in Table 4-5.
Table 4-5. Mandatory Maintenance: CVS Emissions Pre and Post
Deterioration for Vehicles Remaining at 6 Months
°fe-"!air:ten?nce
Pc.t-tlai ntenanco
After 6
Months
Deterioration Rate
i.bin Stci.Dev
I'.ean
Stci.Dev
Mean
Std.Dev
(Gm/mi/1000 mi)
Poil'-isnt
(G'../nn)
(Gm/mi)
(Gm/mi)
h'C
7.59 4.49
O
o\
Co
2.96
10.24
10.40
0.83
CO
108.65 49.99
101.97
46.76
109.50
55.40
1.04
:;3x
2.53 1.40
2.34
1.31
2.31
1.31
-0.01
Vehicle emissions measurements have been analyzed in a similar fashion
for those vehicles remaining at the end of 12 months. Table 4-6 summar-
izes the results.
-------
Table 4-6. Mandatory Maintenance: CVS Emissions Pre and Post Deterioration
for Vehicles Remaining at 12 Months
Pre-Maintenance Post-Maintenance After 12 Months Deterioration Rate
MeanStd.Dev. Mean Std.Dev. Mean Std.Dev. (Gm/mi/lOOOmiJ
Pollutant (Gm/mi) (Gm/mi) (Gm/mi
HC 7.60 4.29 6.98 3.09 11.09 14.11 0.50
CO 105.80 44.82 105.43 44.59 112.51 63.96 0.86
NO 2.63 1.49 2.33 1.37 2.37 1.33 0.00
4.5.3 Interpretation of Results
First six months:
By restricting vehicle owners from maintaining their cars, engine
deterioration appears to cancel any gains achieved by Inspection/Mainten-
ance within a six month interval. Even with 25% of the owners violating
the no maintenance agreement, emissions for hydrocarbons and carbon mon-
oxide are above the initial, pre-maintenance figures for both the idle
and mandatory maintenance fleets.
Second six months:
The problems of vehicle sample attrition and owner maintenance pre-
vent estimation of meaningful deterioration rates during the second six
months. In fact, the results indicate that emissions are down compared
to the six month results. Obviously, there are overriding factors at
work and it seems most reasonable that maintenance by vehicle owners dur-
ing this interval is the most significant. Seventy-five percent of the
vehicles available at the 12 month retest point were found to have been
maintained during the second six months by their owners. The reductions
in hydrocarbons and carbon monoxide have to be a direct result of this
maintenance.
-------
APPENDIX A. DENVER DETERIORATION STUDY ODOMETER READINGS
This listing is extracted from vehicle inspection records at each
nt in the deterioration study. The column headings are defined below
VEH NUM: A number code assigned to each vehicle for
identification throughout the program. The
listing contains the code numbers of the 109
vehicles available for retest at the end of
12 months.
POST-MAI NT:
MILES DRIVEN:
6 MONTHS:
12 MONTHS:
The odometer reading at the time the vehicle
was returned to the vehicle owner following
the initial inspection and maintenance pro-
cedures.
Mileage accumulated during owner use period.
Odometer reading at 6 months.
Odometer reading at 12 months.
-------
V EH
NUM
0 12
u 14
£ 15
G 16
0 17
0 24
0 26
C 27
023
0 29
0 31
0 37
0 38
0 40
0 43
0 45
0 48
0 53
0 60
0 63
G 64
0 66
0 72
U 73
0 7i+
0 75
0 76
0 78
0 79
0 63
0 90
0 91
0 93
0 96
104
10 7
109
115
1 18
1 22
1 26
127
129
1 30
OENVER DETERIORATION STUDY
ODOMETER READINGS
POST-PAINT, MILES b MONTHS MILES 12 MONThS
DRIVEN
DRIVEN
6 30 0 4
3199
662 C 3
2558
68761
4 9237
3310
52547
3489
56036
6 J24G
226i*
62504
3140
6 564^
5 90 0 3
6704
65707
5411
71113
510 45
4849
55894
5333
61227
9 93 4 0
3422
102762
1972
10 4734
84961
3 923
83884
4065
92949
72548
5 321
77369
2585
80454
8 30 2 0
2488
91508
2305
9 3813
5 95 85
2886
62471
3395
6 58 66
60672
5188
65860
6567
72427
52629
2067
546 96
1856
56552
54529
1675
56204
2441
58645
19445
1548
20993
1520
22513
20583
3166
23749
2590
26339
5414
3168
8582
3820
12402
6 40 33
3614
67647
3083
7C73C
42474
337
42811
352
43163
4 5946
3414
49360
5804
55164
42005
1799
43804
554 3
49 3U7
648 75
8974
73849
5389
7 9238
3 7361
3162
40523
468 3
45206
12834
3498
16332
1923
18255
22051
2844
2*895
2338
2 72 33
73336
2971
76307
4690
8 0 997
12609
2678
15287
2385
17672
21387
688
22575
765
2334C
20434
3382
23816
<+189
28005
35284
2816
38100
3875
41975
1 63 0 0
1667
17967
2541
20508
22467
1697
24164
225tt
26422
6704
3408
10112
3127
13239
20817
5708
26525
4255
30780
76369
2 190
78559
2754
81313
5 86 3 0
4180
62810
2 338
65148
7 60 7 8
2569
78647
2828
81475
64169
3064
67233
3069
70302
64860
4412
69272
6064
75336
71128
5910
77038
4321
81359
42146
3769
45915
3597
49512
33735
3564
37299
2896
40195
4 8219
2676
50895
2344
53239
73598
2918
76516
3449
79965
92515
1762
94277
1709
95986
-------
VEH
NUM
132
133
1 40
1 42
143
1 49
153
158
161
166
168
17C
171
175
1 77
179
1 8G
1 81
1 85
1 87
1 90
1 91
196
197
207
2 08
2 11
2 12
213
2 18
222
2 35
2 38
239
2 45
2 47
249
2 51
2 52
2 58
2 60
2 61
2 70
2 71
2 72
2 73
2 76
2 78
2 79
POST- PA INT.
8 97 82
458 98
1+ 8553
2 5592
3 8659
7 82 74
13 04 60
3 J747
<~7191
12474
<~8575
810 58
71092
21117
29493
1 7115
7 67 47
42449
2 <881
1*725
8056
22266
3 6250
11175
11511
27615
63652
51835
61637
16372
6 8526
78046
51016
3 4309
77348
46034
30259
6702
55 99
330 16
23677
6 86 80
95217
59028
92494
<~7305
73426
59885
3829
MILES
6 MONTHS
driven
843 8
9 B 2 2 0
7806
53704
2188
50 74 1
2586
28178
2449
<~1108
<~525
82799
3337
133797
2 653
36400
2 562
<»97 53
6011
1 S<+ 8 5
1977
50552
6<+95
87553
2796
73 88 8
6656
27773
2868
32361
10 342
27457
5114
81861
3121
<~5570
<~386
34267
1922
6647
210 3
10159
2688
24954
5 77k
42024
2820
13995
2353
13864
32 <+3
30858
6136
697 88
3115
54950
6339
67976
6880
23252
2224
70750
2933
80979
<~23
51439
7 2 33
915 <+2
6 8 94
84242
3U9
<~9183
7895
381 54
3653
10355
2496
12095
2127
851 <+3
584
2k 261
8955
77635
11995
107212
2 39 8
61426
2149
9 <~ 5 i+ 3
<~<~09
5171k
3415
768 41
3516
63401
9851
13680
MILES
12 MONTH
DRIVEN
11580
109800
1 0 o7 6
64380
2700
5 3 441
2681
30 859
2375
43483
6039
88838
<~608
138605
3517
39917
2235
51988
6489
24974
2092
5 2 6 44
5969
93522
3 71 6
77604
8219
35992
9490
41851
10732
3 8189
6864
88725
3179
48749
3 6 <~ 3
3791C
3705
1 0352
3468
1 3627
1270
26224
1776
4 3800
<~263
18258
3899
17763
3373
3 4231
7676
77464
128<+
5 6234
7533
75509
10 246
33498
2792
73542
2287
83266
3239
54678
6650
98192
<~153
88395
<~253
53436
8726
46880
5051
15406
6793
1 3888
2042
87185
1328
25589
9332
86967
19137
126349
3287
64713
1956
965 99
<~115
55829
2121
78962
3251
66652
6820
20500
-------
V EH
NUH
2 60
2 86
2 £7
2 91
2 92
2 93
2 96
300
3G7
3 G9
312
314
3 21
3 25
3 26
327
POST- MINT.
MILES
DRIVEN
6 MONTHS
MILES
DRIVEN
96491
2989
6 56 0 9
0
1 7998
2671
52667
5548
29533
5061
19843
5827
52813
2582
6317
4229
29124
1672
71+3 69
529C
8589
4593
20440
3104
12130
1112
16385
5653
7 6050
58 46
51836
9151
99480
2525
65609
70 57
20669
4241
58215
4195
34594
4868
25670
8132
55395
3541
11046
3260
30796
3517
79659
6306
13182
3823
23544
3681
132 42
1153
22038
6799
81896
5663
60987
8141
-------
APPENDIX B. DENVER DETERIORATION DATA
A summary of the vehicle inspection data at each point in the Denver
deterioration study. The column headings are defined below:
VEH NUM:
PRE-
MAINTENANCE:
A number code assigned to each vehicle for
identification throughout the program. The
listing contains the code numbers of the 109
vehicles available for retest at the end of
12 months.
Measured emissions for hydrocarbons (HC), carbon
monoxide (CO) and nitrogen oxide (N0X) in grams/
mile for vehicles at the initial inspection
point of the program.
POST-
MAINTENANCE:
ODOM:
AFTER 6 MONTHS:
Measured emissions after maintenance procedures
have been completed. Data for "PRE" and "POST"
listings for vehicles passing program standards
on initial inspection.
Vehicle odometer reading at given test point.
Measured emissions after 6 months of owner
operation.
AFTER 12 MONTHS: Measured emissions after 12 months of owner
operation.
TAMP: Indication of extent of owner performed mainten-
ance during interval. "LOW" indicates one to
four of the fourteen controlled items showed
evidence of maintenance. "HIGH" indicates
more than four items maintained.
-------
listing oc u'lri? dfte*io^ation oata
ITVS 1175)
VEH.
P9E-MAI NTE
NANCE
POST-M4INTTMANCE
srr
£0 f, ^QMTHS
NUM.
HC
CO
NOX
HC
CO
NOX
ODOH.
HC
C1
NOX
odom.
TAMP
HC
12
7.63
117.7
2.27
7.67
117. 7
2.27
63004
6.62
125.8
1 . 84
66203
LOW
6. 32
14
9.55
9°. n
1.37
9.«^
99. 0
1.37
49237
7. 60
92. 3
1. 9 T
^2^47
NONE
7. 9*
15
13.43
146.4
.67
9.13
1 C9. 4
. 77
6 0 24 C
14. 73
1 74. 5
. V}
62504
LOW
11. 60
16
7.08
118.9
1.55
7.08
118. °
1.55
f 90 C 3
6. 97
131.1
1.24
65707
LOW
7.82
17
10.43
172. 6
1 .54
8.92
162. 3
1 . 16
51045
7.22
179.8
.93
55894
HIGH
43.36
24
7.62
22 1.1
.59
5.59
125. 5
1.16
99340
7. 90
174.3
1.47
102762
LOW
8.53
26
6.01
85.0
4.51
6. 01
85. 0
4.51
84961
5. 97
85.4
4.08
98984
NONE
4.98
27
7.28
11 1. 3
1 .64
7.28
111.2
1. 64
72548
12. 41
1 61.1
.99
77869
LOW
10. 98
28
15.35
20 2.0
1 .47
7. 45
181.2
.80
89020
*.50
1 73.5
.57
91508
NONE
35. 94
29
11.15
193.9
.61
8.29
lc«. 9
.93
5 95 8*
11 • 4 *
1 96.9
.71
624*1
N0NF
12.45
T 31
8.24
152.9
1.26
7.90
151. 0
1.25
60672
9.93
171.9
.69
65860
NONE
8. 71
37
8.85
129.5
1.67
12.51
145. e
1. 32
52629
15.96
169. 8
1.11
54696
LOW
11. 18
36
6.02
167.3
3.31
8.02
If 7. 3
3.31
54529
13.45
196.3
2.53
56204
NONE
11. 98
i»0
<~.55
48.9
5.37
7. 89
47. ?
3.40
19445
4. 39
63.9
3.7 8
20993
NONE
3.98
<~3
5.68
62. 4
2.4;
4.6''
61.. 4
2. 33
20 5 97
4.75
«3. 4
2.09
2374C
NONP
4. *9
45
. 3.81
94.2
3.07
3.6?
86. 5
3.14
5414
4.J6
97.?
4. 20
8^82
NONE
¦?. 79
*»8
9.03
56.1
9.08
9.03
56.1
9.08
64033
6.26
69.7
6.64
67647
NONE
5.55
53
7.33
94.7
3.33
5. 72
57. 8
3.82
4 24 74
*. 31
63. 0
4.42
42811
NONE
6. 36
60
5.55
173.1
2.22
. 5. 55
173. 1
?. 22
45946
5.53
141.6
2.3 5
49360
LOW
"*,99
63
10.11
16 8. 1
1.68
1C.58
tc9. 8
1.57
4200 5
7. 75
1 23. 3
?. 0 0
43804
LOW
7. 25
64
4.43
68.1
5.24
U . 4 3
F8. 1
5.24
*4975
5.32
71.7
6. ?4
*3849
HIGH
4.09
66
6.69
70.7
2.64
5. 27
63, 7
?. 76
3 73 61
4. 77
60.9
3.53
41 523
N ONp
3 .48
72
2.66
40.1
2.52
2. 51
21. t
2.53
12834
2. 49
30.7
3. 22
16 332
LOW
7.99
73
4.55
44. 8
3.53
4. 06
46. 9
3. 78
22051
5. 01
48. 0
3.4 1
24895
NONF
5. 47
7V
6.92
8 8.7
5.02
7.42
100 . 9
2.71
73336
9.14
104.3
2 .?7
76307
LOW
7.55
75
7.40
75.3
1.49
3. OQ
r4. 4
t. 35
12609
c.
71.*
1 ."'0
15?87
NOME
5.48
76
8 . 7 i»
208. 6
.61
P. 7u
'0 8. 6
• 66
21887
9.8?
1 99 . 1
.79
22575
NONr
14. 2*
7.8
<~ .56
87.6
4.9?
4. 86
87.6
4.93
20434
11. 99
84 . 7
4. 0 5
?3916
NONE
5. *9
79
6.05
90.7
4.29
4.95
64. 3
5.35
35294
14. 84
94.9
5.64
3 8 108
NONF
4. 79
83
4.44
93.2
1.7 9
4. 62
52. ?
2. 56
163C0
3.99
45.9
1 .85
179*7
LOW
4. 82
Af- Trc 12 MONTHS ..
CO NOX 300M, TflHP
107.0
90 .2
164. ?
153.6
2 34.2
162 .4
63. 3
1(13.9
180.1
17.3.9
185. 9
150.3
210 .3
47.0
*2 . 7
86.3
65.5
64.0
116. 0
104.6
71.9
29 . 9
39.8
64. 3
97.1
97.5
237 . 3
97.9
7 8.7
73.5
2.02
1.77
.59
.97
.70
1.5 C
5.67
1.55
.73
. . R C
.7 0
.80
1.28
3. 36
1.64
3.2 2
5.73
<* . 87
2.43
2.55
2.92
2. 3<*
3.18
4. 93
2.08
.73
.78
3.66
<~.17
2.21
69761
56Q36
e.5644
71119,
61227
104734
.9294*
30 454
93813
6 5 856_
72427
56552
58845_
22513
2*33 9
1240 2
70730
<~3163
_551_64_
49^47
79239
4 5 206
18255
27233
80997
1767?
?334C
28035
<~1975
205D8
LOW.
HIGH
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
LOW .
HIGH
_1.M
LOW
LOM
MONE
LOM
HlGai
LOW
HIGH
HIGH
LOW
NONE
L OH
LOW
LOW
LOW _
LOW;:,
-------
LISTTNr, r)P HENV^R O^T FR TO^ AT I ON OATA
(CVS 1175)
VEH.
PRE-'
M AINTrNflNCE
PQS T-M<\ INT
ENANCE
AFTEP S MONTHS
NUM.
HC
CO
NOX
MC
CO
NOX
onoM.
HC
ro
NOX
OOOH.
90
3.
7U. 5
'.6 7
3 0 7JJ0
HIGH
NONF
10. l
-------
Lt^TTMT, OP "»FNVFR nETF" 10"? fiTION noro
(CVS 1975)
VEH.
PRE-I
maintenance
POST-MAINTENANC
E
AFTER 6 '
MONTHS
NUM.
HC
CO
NOX
hc
CO
NOX
000 M.
HC
CO
NOX
nno*.
180
6.3?
6 ® . 1
6.73
6.76
100.
c
3.41
76 74 7
5.97
«4. 3
4. 61+
81861
181
7.05
92.3
3.07
5.6 4
1C 3.
5
». 0 <~
4244 9
5 . 75
"4. e
2.
<•5 57 0
185
5.45
50.1
2.5?
1.67
34.
Q
1.81
29881
3. 49
44. 9
1. 59
342 6 7
187
<~.72
90.6
1.93
<~.39
8 3.
5
1. 35
47 25
<~.63
87.2
1 . 53
6647
190
3.62
51.2
3.05
3.62
51.
2
3.05
8056
3.94
66.7
2. 36
10159
191
14.82
138.8
1.36
1«». 34
151.
2
1.38
22266
10.78
138.1
1. 18
24954
196
<~.96
<~9.6
5.7?
4. 28
53.
e
<~.59
36250
5.69
70.4
4.91
42024
197
5.28
80.2
3.0 3
5.28
P0.
2
*.03
111 75
5.13
96.6
1.69
1 3995
207
5.09
35. 4
4. 04
5. 09
35.
4
4.04
11511
3.49
30.0
? . 79
1 3964
.208
<~..3 7
<~2.2
3.61
<~.36
<~6.
e
2.91
27615
3. 75
<~5.2
3.4 3
30 858
211
28.91
121.0
3.54
4.93
111.
<*
2.49
63652
5.67
141.7
1. 68
69788
co 212
15.29
165.4
.79
12. 12
141.
8
1.16
51835
15. 34
88.4
1.12
54950
213
H. 15
158.7
2.28
1U. 15
158.
7
2.28
61637
10 .67
148.0
2.51
67976
218
6.10
99.8
1.52
6. 24
120.
8
. 91
16372
5. 29
115.5
1.0 7
?1!252
222
6.3?
76.0
3.0?
6. 32
76.
0
3.0?
68526
4. 35
44 . 2
3.42
7075C
_235
24.44
. 238.5
1.50
27.60
248.
2
1. 99
79046
15.59
3 J6.8
1.89
90979
238
9.63
115.7
3.32
10.83
205.
2
.57
51016
14. 86
260.7
.57
51439
239
<~.66
101. 7
.87
<~.16
61.
8
1.98
84309
4.4 9
63.2
2.15
91542
2k5
7o 53.
91-7
1.60
B.M
112.
(
.89
7731* 8
7.66
55.8
1.44
94242
247
6.1*3
80 .4
6.10
<~.17
25.
1
6.59
460 34
<~.05
23.1
6.12
49183
2<* 9
7.52
157.5
1.6?
5.7*
124.
5
1.56
30259
9.91
180.9
1. 36
38154
,251
3.15
. .71.1
1.47
3., 0 8
7 8.,
1.2?
6702
?. 66
63. 5
1. 59
1 0 355
252
<•.07
77.9
1.08
3. 20
59.
0
1.26
95 99
<*. UO
59.0
1.48
12095
258
7.54
156.9
2.21
8. 89
167.
5
7.15
83016
9.49
232.5
1.63
85143
260
_£»81
138,7
1. 83
5. 81
138.
7
1.83
236 77
5.40
121.2
1. 94
24 261
261
<~.66
95.c
1.25
5.97
118.
0
1.16
68680
4. 94
68.2
1 .97
77635
270
3.26
4 2.3
3.56
2*
42.
"a
56
95217
3.90
37 . 0
6.63
107212
271
10.33
157.2
1.62
8. 20
153.
2
1.23
59028
9. ?9
13 9.0
1.17
61426
272
8.52
153.0
2. 87
6.67
116.
5
3. 12
9249 4
43. 97
198. 0
1 .23
94643
273
6.28
125.3
2.06
6.96
113.
1
3. 81
<~7305
5.2k
93.2
3. 72
51714
AFTEF 12 MONTHS
TAMP
HC
CO
NOX
0001.
TAMP
NONF
? 9. 4 2
92.1
3.19
88725.
HIGH
MON^
6. n8
82. 3
2. 38
4871*9
HIGH
NONF
3.2 7
25.6
2.15
37910
LOW
NOME
4. 70
75.6
2.08
10 352 _
LOH _
NONE
4. 30
61.7
3.01
13627
NONE
LOW
9. ?1
116. 0
1.35
26 2?**
LOW
NONE
4. 35
47.9
4.90
43800
LOK
NONE
3. 62
55.5
1.88
18 258
NONF
NONE
6.63
24.0
5.13
17 763
NONE
NONE
?. 56
26,8
3.62
34231
HIGH
NONE
5.17
98.2
2.32
7746<»
, NONE
LOW
14. 32
160.1
.66
5623<»
LOW
NONE
10.09
121.1
1.3_0
75509
LOW
NONC
5.54
103. 3
1. 37
33498
LOW
NONE
5. 31
53. 0
2.45
73542
NONE
LOW
13. 07
2 4 3 .5
1.19.
. 93266 NONF
NONE
15.42
238.1
.91
54678
NONE:
NONE
6.7*
128.9
1.01
98192
LOW
HIGH
11.18
95.9
1.^0
33 315 HIGH
NONE
16 .1?
19.4
6.22
53436
HIGH
NONE
8. 58
178.7
1.81
46880
NONF
LOW
3. 00
64. 9
?. 35
15406
NONE
NONE
4. 32
58.0
1.85
18888
LOW
LOW
9. 06
173.7
3.29
87185
LOW
NONE
6.74
102.7
3.81
25589 NONE
NONE
5. 98
107.9
1.59
86967
LCW
NONF
3.61
3A. ?
5.66
126349
HIGH
NONE
19.97
342 . 9
• 3 C
NONE
94. 43
233. ?
.85
96599
NONE
NONE
5.83
102.9
2.75
55839
-------
LISTING OF OFNVFR DFT rRIOP AT ION OA T ft
fCVS 1975J
VEH.
P.RE-M AI NTEN ANCE
POST-MAINTENANCE
AFTER 6 MONTHS
.AFTER.
12 MONTH.S
NUM.
HC
CO
NOX
HC
CO
flOX
OOOM .
HC
CO
NOX
ODOM.
TAMP
HC
CO
NOX
ODOM.
TAMP.
276
8.88
125.1
3.0^
7.00
118. 5
3.10
71kZh
9.27
128.7
3.62
768«tl
NONE
in.79
1«*2. «~ .
3.82 .
7 8.96 ZL_
JLIGM
2 78
6.20
87.?
2.95
6. 20
67.2
?. 95
59885
5. 37
92.
2.36
63 *+0 1
NONE
5.80
93.7
1.86
66652
NONc
279
1.1k
59.7
2. 85
?. 3k
59. 7
85
382 9
3. 39
51.5
2 .57
1368G
NONE
3.76
1*7.2
3.96
20500
LOW
280 .
13.12
J. 7 0.5
..1.01.
13. 07
16 5.. .3
. ..97_ .
96
------- |