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TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1
2.0 EMISSION FACTORS 3
2.1 Fleet Description 3
2.1.1 EPA Surveillance Database 3
2.1.2 Technology Distribution Projections ... 6
2.2 Emission Level Groupings 7
2.2.1 Passing FTP Emitters 7
2.2.2 Marginal Emitters 9
2.2.3 High Emitters 10
2.2.4 Super Emitters 15
2.3 General Methodology 17
2.4 Emission Factor Results 18
3.0 I/M BENEFITS 20
3.1 Short Test Data 20
3.2 Identification Rates 21
3.3 Repair Effects from I/M 23
3.3.1 Repairs Database 24
3.3.2 Emission Reduction from Repairs 25
3.4 General Methodology 28
3.4.1 Annual Inspections . 28
3.4.2 Biennial Inspections 29
3.4.3 Idle I/M Credits 30
4.0 NORMALIZED BAG FRACTIONS 31
5.0 HIGH ALTITUDE 35
5.1 Emission Factors 35
5.2 High Altitude I/M Credits 37
5.3 High Altitude Bag Fractions 37
Appendix 38
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1.0 INTRODUCTION
The MOBILE4 Tech IV Credit Model is used to estimate the
emission factor equations, the effects of Inspection and
Maintenance (I/M) programs, and the bag fraction equations for
1981 and later passenger cars. The model's results are then
stored in the EPA MOBILE4 emission factor model. This report
describes the development, use, and results of the Tech IV
model. It also documents the normalized bag fractions, high
altitude emission factors, biennial I/M credits, and idle
emission I/M credits used in MOBILE4.
MOBILES, EPA's previous emission factor model, used a
similar modeling approach. Details on this model can be found
in the report "Tech IV Credit Model : Estimates for Emission
Factors and Inspection and Maintenance Credits for 1981 and
Later Vehicles for MOBILES" (EPA-AA-IMG-85-6).
The technology used to meet the stringent emission
standards beginning with the 1981 model year is continually
being improved. For instance, many manufacturers have utilized
closed-loop control since 1981; others, however, did not adopt
it product-wide until more recently. Fuel injection use has
also grown dramatically in the past few years. It has
increased from 8.5% of fleet sales in 1981, to 81.1% in 1988,
and is projected to comprise 95.7% of the 1992 model year.
In the Tech IV Model, the fleet is separated into three
technology groups. They are open loop vehicles (OL)
including both carbureted and fuel injected vehicles',
closed-loop carbureted vehicles (CARB), and closed-loop fuel
injected vehicles (FI). The data were separated into the three
technology groups for several reasons. The open and
closed-loop vehicles were separated because of large
differences in emission levels. Also, the open and closed-loop
systems are technically very different. They generally utilize
completely different principles to control emissions and engine
functions and when they fail it is frequently in a different
manner. Repairing vehicles of these two technologies often
requires different diagnostic procedures, tools, replacement
parts, and expertise. The closed-loop vehicles were further
divided into carbureted and fuel injected types. Overall, the
emissions of these technologies did not differ greatly.
However, they are technically quite different in their
operation, failure mode, adjustment, and repairability. Also,
the fuel injected technology is the more important one in terms
of future emissions predictions, since it is rapidly dominating
the market and will continue to do so in the future.
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The MOBILE4 Tech IV Credit Model predicts the emission
levels of each distinct technology separately and then combines
the results based on the fraction of the vehicle fleet which
uses each technology in each model year group.
The sample of passenger cars is also separated into two
model year groups. These two groups are the 1981 and 1982
model year cars and the 1983 and later model year cars. The
differences in these groups are largely the result of CO
waivers granted to most 1981 and 1982 cars and the gradual
improvement of closed-loop technology throughout the 1980's.
The MOBILES version of the Tech IV Credit Model divided
the sample into three emission level categories. For the
MOBILE4 Tech IV Credit Model these categories have been
modified and expanded to include a fourth category. They are
1) passing FTP, 2) marginal emitters, 3) high emitters, and 4)
super emitters.
The general approach of the MOBILE4 Tech IV Model is to
obtain statistical information about the emission levels of
each category by emission standard and technology and to
predict the emission levels of that category at any specified
age measured by mileage. All categories are then weighted
together based on their predicted size in each model year group.
The emission reduction credits allowed inspection and
maintenance (I/M) programs for inspection of 1981 and newer
passenger cars are also estimated using the Tech IV model.
Successful inspection and maintenance programs, as their name
implies, are the result of two factors: identification of high
emitting vehicles through failure of an emissions test, and
proper repair of these vehicles. Data on both of these aspects
of I/M have been collected, analyzed by EPA, and included in
the model.
-2-
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2.0 EMISSION FACTORS
2.1 Fleet Description
2.1.1 EPA Emission Factors Surveillance Database
The database was created from data collected in EPA's
in-use emission factor surveillance program. The cars in this
program were randomly recruited and thoroughly emission
tested. The data from these vehicles were used to calculate
the emission factors, the percent of excess emissions
identified by the I/M tests, and the bag fractions. This
database consists of 1,697 light-duty vehicles with model years
1981 through 1986. It contains 659 1981 and 1982 vehicles
certified to the 7.0 gram CO standard. These vehicles were
included because they were so numerous; however, their use was
restricted to modeling only the 1981 and 1982 model years.
All the vehicles in the sample were examined for
emissions systems tampering. However, not all forms of
tampering yield significant exhaust emissions increases.
Tampering of the air pump system, catalyst removal, misfueling
of catalyst equipped cars with leaded gasoline, and EGR system
disablements were considered reasons for removal from the
database. There were 89 vehicles identified with such
tampering in the EPA surveillance database. All of them were
removed. Table 2-lb provides a distribution and shows the
average excess emissions due to tampering among tampering types
and model years for the vehicles which were removed.
MOBILE4 adjusts the emission levels predicted by the Tech
IV Credit Model to reflect the emission impact of tampering
separately. The emission values which are part of this
calculation are displayed in the row entitled MOBILE4 (See
footnote at the bottom of Table 2-lb).
Three major technology divisions were used for modeling
the emissions of passenger cars. These were:
o Closed-loop carbureted (CARS)
o Closed-loop fuel-injected (FI)
(both MFI and TBI)
o Open-loop carbureted and fuel-injected (OL)
Table 2-la shows the distribution of the database,
excluding tampered vehicles, by model year, technology, and CO
certification standard.
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Table 2-la
Distribution by Technology and Model Year
Model
Year
All
Closed
Carbureted
3.4
253
7
57
0
68
25
7.0
344
60
-
-
-
-
Loop
FI
3.4
33
13
168
64
52
22
7.0
8
64
-
—
-
-
Open
3.4
196
17
47
0
16
0
Loop
7.0
145
38
-
-
-
-
1981 253 344 33 8 196 145 979
1982 7 60 13 64 17 38 199
1983 57 - 168 - 47 - 272
1984 0 64 - 0 64
1985 68 52 - 16 136
1986 25 = 22 - 0 = 47
TOTAL 410 404 352 72 276 183 1697
-4-
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Model Year
1981
1982
1983
1984*
1985
1986
All
MOBILE4**
Model Year
1981
1982
1983
1984
1985
1986
All
MOBILE4**
Model Year
1981
1982
1983
1984
1985
1986
All
MOBILE4**
Table 2-lb
Distribution and Average Emissions
of Tampered Vehicles by Model Year
Air Pump Tampering
N
19
8
0
0
0
1
28
N
52
3
2
1
1
0
59
N
1
1
0
0
0
0
HC
1.28
2.35
0.00
1.61
1.55
CO
30.72
29.72
0.00
30.47
30.13
Fuel Inlet Tampering
HC
0.33
0.05
0.00
0.00
0.00
0.32
2.14
CO
4.25
1.55
0.06
0.00
0.00
3.92
15.68
Catalyst Tampering
HC
6.45
3.23
CO
172.6
19.7
NOX
0.33
0.34
0.00
0.34
NOx
0.34
0.23
0.00
0.00
0.00
0.34
1.55
NOx
0.00
1.35
4.84
2.74
96.1
22.8
1.35
1.55
* The small number of tampered vehicles in later model years
reflects the EPA policy of generally rejecting tampered
vehicles from the in-use testing program.
** The MOBILE4 numbers are the basic 50,000 mile emission
rates for 1981 vehicles from Table 2-14 of this report
plus the excess added by MOBILE4 per tampered vehicle for
a given tampering type. This provides a point of
comparison to the test data on the tampered vehicles which
were removed from the analysis. The final MOBILE4 number
for all the vehicles in a model year is the product of the
tampering excess and the tampering rate plus the basic
emission rate.
-5-
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2.1.2 Technology Distribution Projections
Most information about the mix of the technologies was
taken directly from actual sales data provided by the
manufacturers. For model years not yet produced, and for
recent model years where sales information is not yet
available, projections of the future technology mix were needed.
All estimates for 1987 and later model years were based on 1986
model year actual CAFE sales data, modified by sales fraction
projections provided by most of the major manufacturers. CAFE
sales projections (General Label) were generally not used,
except for some engine families introduced after the 1986 model
year.
Some general rules for estimating the technology
distribution were used:
o The 1988 model year distribution is estimated using
the actual total 1986 sales for those carbureted
engines still available in 1988. New carbureted
engines for 1988 assume the sales projected by the
manufacturer for that engine in 1988.
o All carbureted engines remaining in 1988 which are
not the largest or the smallest engine offered by a
manufacturer are assumed to convert to fuel
injection by the 1992 model year.
o Engines with both carbureted and fuel injected
versions are assumed to convert sooner than engines
that are strictly carbureted. Engines with larger
fuel injected version sales than carbureted sales
estimated for 1988, are assumed to drop the
carbureted version for the 1990 model year. Others
discontinue the carbureted version for the 1991
model year.
o Manufacturer market share is assumed to remain
fixed at 1986 model year levels.
o Engine sales in each size are assumed to remain
fixed at 1986 model year levels.
o None of the carbureted engines that were available
in 1988 are assumed to be completely converted to
fuel injected before the 1990 model year. However,
carbureted sales are assumed to drop linearly
between 1988 and 1990.
o The projected 1992 distribution is assumed to
continue indefinitely.
-6-
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The technology projections used in calculating
weighted emission values are given in Table 2-2 below.
Table 2-2
Passenger Car (LDGV) MOBILE4
Technology Distribution by Model Year
the
Model
Year
Technology Group
Closed-Loop CLS
Fuel Injected Carbureted Open Loop
1981 0.084 0.635 0.281
1982 0.171 0.499 0.330
1983 0.303 0.456 0.241
1984 0.485 0.460 0.055
1985 0.545 0.393 0.062
1986 0.670 0.260 0.070
1987 0.747 0.239 0.014
1988 0.811 0.189 0.000
1989 0.837 0.163 0.000
1990 0.863 0.137 0.000
1991 0.916 0.084 0.000
1992 0.957 0.043 0.000
For exhaust emissions, TBI and PFI were not distinguished
since no large differences in performance were noted in the
data. The evaporative emissions portion and the temperature
correction factor portion of MOBILE4 do distinguish TBI and
PFI. Documentation for the non-exhaust portions of MOBILE4
will be provided elsewhere.
2.2 Emission Level Groupings
2.2.1 Description of Passing Emitters
A Passing emitter is defined as a vehicle which passes
the FTP Certification standards for both HC and CO. The NOx
emission value is not used in determining an emitter type. It
is assumed instead that all vehicles comprise one NOx emitter
category. For programming convenience these were referred to
as "Passing" NOx emitters, although they may exceed the FTP
standard for NOx. Also, I/M programs are assumed not to affect
NOx emissions directly; therefore, no NOx I/M credits are
produced. However, I/M programs help deter tampering which
reduces NOx emissions slightly.
The emission levels and mileages of the Passing emitters
in the surveillance database are shown below in Table 2-3
stratified' by technology and model year. On average these
vehicles are approximately 40% below their FTP standards for HC
and the 1983 and later vehicles are approximately 30% below the
-7-
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FTP CO standard. The passing vehicles make up about 46% of the
surveillance database sample. The data indicate that for FTP
passing vehicles there is very little emissions difference
between technologies.
Table 2-3
Description of the Passing Emitters
Model Year
1981
1982
1983
1984
1985
1986
ALL
Model Year
1981
1982
1983
1984
1985
1986
ALL
Model Year
1981
1982
1983
1984
1985
1986
ALL
Carbureted
Sample
259
54
32
0
43
20
HC
0.267
0.256
0.236
-
0.233
0.227
Vehicles
CO
2.978
2.859
1.894
—
1.914
1.838
NOx
0.801
0.729
0.796
—
0.751
0.678
408
0.258
2.709
0.780
Fuel Injected Vehicles
Sample HC CO NOx
20
47
74
21
20
16
198
Sample
121
37
12
0
2
0
172
0.249 2.614 0.675
Open Loop Vehicles
HC
0.290
0.265
0.257
0.335
0.283
CO
2.671
2.827
2.749
NOx
0.769
0.748
0.665
2.260 0.680
Mile
19,691
6,695
18,029
30,979
23,221
19,203
Mile
0
0
0
0
0
0
.272
.257
.239
.245
.234
.263
2.
3.
2.
2.
2.
2.
344
376
389
347
650
059
0.
0.
0.
0.
0.
0.
799
679
623
788
665
608
24
31
27
17
35
30
,310
,417
,853
,933
,728
,706
2.705 0.756
28,315
Mile
24,269
3,017
23,819
21,380
19,632
-8-
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When the fleet is at zero mileage, the model assumes most
vehicles are Passing emitters (Further details are provided
below). As the vehicles of a given model year accumulate
mileage, the number of Passing emitters decreases and the
number of other .types of emitters grows. The decrease in the
number of Passing emitters with increased mileage is the result
of the increased number of failed emission control components.
In addition, the emissions of Passing emitters are assumed to
have a gradual deterioration due to normal use. This
deterioration is calculated by regressing the emissions of the
Passing emitters versus mileage. The deterioration and zero
mile level are shown in Table 2-4 for each technology and model
year group.
Since there were only 14, 1983 and newer open-loop
vehicles in the sample, the deterioration rate of the 1981 and
1982 open-loop vehicles was assumed for the 1983 and newer
vehicles as well. The zero-mile and deterioration rates for
the other 1983+ technologies are based only on 1983 and later
model year vehicles.
Table 2-4
Emission Levels of the Vehicles Passing FTP
MYR Group Technology
N
1981-82 Carbureted 313
1981-82 Fuel Injected 67
1981-82 Open Loop 158
1983+ Carbureted 95
1983+ Fuel Injected 131
1983+ Open Loop 14
Zero-Mile
HC
0.244
0.229
0.260
0.192
0.232
0.240
CO
2.686
2.368
2.465
1.619
2.176
2.385
Deterioration
per 10k miles
HC CO
0.0122
0.0111
0.0124
0.0162
0.0039
0.0124
0.156
0.239
0.126
0.109
0.078
0.126
2.2.2 Description of Marginal Emitters
The Marginal emitter category is new for MOBILE4. It was
added to better model the emission behavior of vehicles whose
emissions are not enough to make them High emitters, yet which
do not pass the FTP certification standards for one or both
pollutants. Unlike the passing vehicles, most of these
vehicles have some minor engine or emission control system
problems which cause them to exceed FTP standards. It was also
desirable to separate these vehicles in modeling the I/M
benefits. Their behavior toward testing and repair is often
quite different than that of the High emitters.
-9-
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For consistency, the Marginal emitters were split into
the same technology groups and model year groups as the Passing
emitters. The three technology groups were all open loop,
closed loop carbureted, and closed loop fuel injected. The
model year groups were 1981-82 and 1983 and later.
The EPA surveillance database contains 735 Marginal
emitting vehicles. This corresponds to 43% of the sample. On
average these vehicles exceed HC FTP standards by about 20%
However, the average fuel injected marginal vehicle did not
exceed the HC FTP standards, indicating that many of these
vehicles are CO-only failures. It also demonstrates that on
average, Marginal fuel injected vehicles emit less than
carbureted. The average 1983 and later Marginal emitting
vehicle in the sample exceeded its CO FTP standard by
approximately 40%.
The corresponding emission levels for the Marginal
emitters in the surveillance database are shown in Table 2-5.
Emissions data from the Marginal vehicles are used to
create three input parameters to the MOBILE4 Tech IV Model.
These are the deterioration in the emission level, the initial
emission level, and the growth rate of the Marginal emitter
category. The first two parameters are obtained from a linear
least squares regression of the HC and CO emissions data of the
Marginal vehicles. The zero-mile intercept is used as the
initial emissions level and the slope of the regression
represents the gradual deterioration that a Marginal emitting
vehicle would undergo with normal use and maintenance. These
parameters are shown in Table 2-6 by technology and model year
group.
The growth rate of the Marginal emitter category is the
rate at which Passing vehicles turn into Marginals, or the rate
at which vehicles become FTP failures. These parameters were
developed by coding all marginal emitting vehicles which passed
as a zero and all failing vehicles as a one. The coded data of
ones and zeroes were then divided by technology and model year
group and regressed versus mileage using least squares. The
FTP failure rate regression parameters which were obtained are
displayed in Table 2-7 for each technology and model year group.
2.2.3 Description of High Emitters
For MOBILE4, High emitters are defined in a statistical
manner. The sample was first separated into the same
technology and model year groups as the Passing and Marginal
vehicles. For each of these groups, the logarithmic
distribution of the emissions was computed. A High emitter was
-10-
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Model Year
1981
1982
1983
1984
1985
1986
ALL
Model Year
1981
1982
1983
1984
1985
1986
ALL
Model Year
1981
1982
1983
1984
1985
1986
ALL
Table 2-5
Description of the Marginal Emitters
Sample
255
9
19
0
18
5
306
Sample
16
13
79
35
29
4
176
Carbureted
HC
0.565
0.767
0.552
-
0.329
0.238
0.551
Fuel Injected
HC
0.482
0.481
0.352
0.355
0.420
0.470
0.388
Vehicles
CO
6.832
9.193
4.996
-
4.934
5.038
6.646
Vehicles
CO
5.821
6.569
4.823
4.705
4.181
4.030
4.895
NOx
1.010
0.914
1.142
—
0.852
0.434
0.997
NOx
1.375
1.324
0.729
0.840
0.738
0.410
0.848
Mile
43,398
76,829
37,720
-
32,752
25,989
43,118
Mile
42,255
54,158
34,255
30,504
36,429
27,095
35,901
Open Loop Vehicles
Sample
190
15
35
0
13
0
HC
0.525
0.500
0.398
-
0.522
-
CO
7.336
6.890
4.881
-
5.952
-
NOx
0.795
0.637
0.652
—
0.615
-
Mile
41,640
21,087
24,190
—
33,891
-
253
0.506
6.899 0.757
37,609
-11-
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Table 2-6
Emission Levels of the Marginal Emitters
MYR Group Technology
1981-82
1981-82
1981-82
1983+
1983+
1983+
Carbureted
Fuel Injected
Open Loop
Carbureted
Fuel Injected
Open Loop
N
264
29
205
42
147
48
0
0
Zero-Mile
HC
533
428
0.468
0.348
0.367
0.370
CO
5.358
5.333
6.818
4.600
4.361
4.880
Deterioration
per 10k miles
HC CO
0.0087 0.349
0.0113 0.173
0.0137 0.121
0.0207 0.109
0.0008 0.085
0.0230 0.108
MYR Group
1981-82
1981-82
1981-82
1983+
1983+
1983+
Table 2-7
Rate of FTP Failures per 10,000 Miles
Technology Zero-Mile Growth
@50K
Carbureted 0.2079 0.09537
Fuel Injected 0.1056 0.07877
Open Loop 0.3548 0.07322
Carbureted 0.0889 0.09479
Fuel Injected 0.3598 0.06729
Open Loop 0.7025 0.02835
0
0
685
499
0.721
0.563
0.696
0.844
-12-
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judged to be any vehicle whose HC or CO emissions were more
than two standard deviations from the log mean of the sample.
Table 2-8 gives the actual HC and CO cutpoints, for each
technology and group, that determine the lower boundary of the
High emitter category. To prevent outliers from being
classified as High emitters, an upper bound was established at
150 g/mile CO and 10 g/mile HC.
MYR Group
1981-82
1981-82
1981-82
1983+
1983+
1983+
Table 2-8
Definition of a High Emitter
FTP (qm/mi)
Technology
Carbureted
Fuel Injected
Open Loop
Carbureted
Fuel Injected
Open Loop
HC
1.175
0.725
1.112
0.815
0.965
0.837
CO
17.411
10.499
21.638
10.398
10.558
10.139
Table 2-9 presents the zero-mile levels and deterioration
rates of the High emitters. The emissions of the High emitters
are assumed to deteriorate at the same rate as Marginal
emitters of the same model year group and technology. The
zero-mile level was calculated using the average emissions of
the Highs and the deterioration rates of the Marginals for each
technology and model year group. The method was to subtract
from the average emission level of the Highs the product of the
deterioration rate and the average mileage of those High
emitters. The deterioration and zero-mile levels of the High
emitters are shown in Table 2-9.
Table 2-9
Emission Levels of the High Emitters
MYR Group Technology
1981-82
1981-82
1981-82
1983+
1983+
1983+
Carbureted
Fuel Injected
Open Loop
Carbureted
Fuel Injected
Open Loop
N
80
22
33
13
26
2
Zero-Mile
HC
CO
2.198 33.659
0.861 11.901
2.179 31.933
0.954 13.197
1.260 13.789
2.123 32.014
Deterioration
per 10k miles
HC CO
0.0087
0.0113
0.0137
0.0207
0.0008
0.0230
0.349
0. 173
0. 121
0. 109
0.085
0. 108
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For the MOBILE4 Tech IV Model, data on High emitters are
used to create two other parameters. These are the growth in
the High emitter category at low mileage and the accelerated
growth in the High emitters after 50,000 miles - the "kink."
It is assumed that no High emitters exist at zero miles, but
that vehicles start to become High emitters as soon as they are
driven. The proportion of High emitters then increases for a
given model year at a linear rate until it reaches 50,000
miles. After 50,000 miles, the rate of occurrence of High
emitters increases. This increase might be due to such factors
as loss of warranty coverage or generally poor maintenance
given to used cars by second owners.
The increased rate in the number of High emitters for all
technologies and model years was calculated using the following
methodology.
1. The fraction of High emitters was found in the
sample of vehicles which had less than 50,000 miles.
2. The average mileage of all the cars in the sample
which had less than 50,000 was calculated. This
sample was formed by combining both model year
groups and the three technology groups. A more
disaggregated approach would have been preferred,
however, insufficient data above 50,000 miles for
all the groups prevented it.
3. The rate of increase of High emitters per 10,000
miles was calculated by dividing the fraction of
High emitters by the average mileage.
4. Using the rate developed in step 3 and assuming
that at zero miles there were no Highs, the number
of Highs at 50,000 miles was calculated.
5. The fraction of High emitters was found in the
sample of vehicles which had more than 50,000 miles.
6. The average mileage of all the cars in the sample
which had more than 50,000 miles was calculated.
7. The mileage beyond 50,000 miles was determined by
subracting 50,000 from the average mileage.
8. The increase in High emitters was determined by
subtracting the number of High emitters predicted
at 50,000 miles (from Step 4) from the fraction of
High emitters among vehicles with more than 50,000
miles.
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9. The increase in High emitters was divided by the
mileage beyond 50,000 to determine the rate of
increase for High emitters after 50,000 miles.
10. The rate of increase after 50,000 miles was divided
by the rate for vehicles before 50,000 miles to
give the adjustment factor for the. accelerated
growth.
11. This is the "kink" and its calculated value is 3.1.
The growth in the number of High emitters up to 50,000
miles is shown for each technology and model year group in
Table 2-10.
Table 2-10
Growth in the Number of
High Emitters per 10,000 Miles
MYR Group
1981-82
1981-82
1981-82
1983+
1983+
1983+
Technology
Carbureted
Fuel Injected
Open Loop
Carbureted
Fuel Injected
Open Loop
Growth
0.016257
0.022202
0.011799
0.023528
0.015340
0.008304
2.2.4 Description of Super Emitters
There are nine vehicles in the EPA surveillance database
which exceed either 150 g/mile CO or 10 g/mile HC. The repair
databases, as discussed in Section 3.3.1, provided an
additional eight vehicles which met these critera. These
vehicles are outliers and are classified as Super emitters.
All seventeen vehicles had closed-loop systems. Thirteen of
the vehicles were carbureted and four were fuel injected. A
list of the seventeen vehicles, their emission levels, mileage,
and a brief description are presented in Table 2-11. Since
there were only four fuel injected vehicles, they were combined
with the other thirteen carbureted Super emitters to determine
the average emissions of a Super emitter.
-15-
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Veh ft
MYR
Table 2-11
Description of the Super Emitters
Make Std Fuel Mileage HC
CO
NOx
58*
408*
462*
5206*
5238*
6045*
5045*
3139*
109
272
274
305
329
5144*
423
629
1107
1981
1981
1981
1982
1984
1984
1982
1981
1981
1981
1981
1981
1981
1981
1984
1982
1984
PONT
CHEV
PONT
CHEV
CHRY
FORD
OLDS
MERC
OLDS
BUIC
AUDI
CHEV
PONT
BUIC
CHRY
PONT
PONT
3
7
7
7
3
3
7
3
3
3
3
7
7
7
3
7
3
.4
.0
.0
.0
.4
.4
.0
.4
.4
.4
.4
.0
.0
.0
.4
.0
.4
GARB
GARB
CARB
GARB
TBI
TBI
CARB
CARB
CARB
CARB
MFI
CARB
CARB
CARB
MFI
CARB
CARB
5,710
25,440
30,740
80,050
30,340
55,720
94,321
50,740
29,266
70,147
27,574
115,833
71,004
52,126
6,523
67,522
44,424
8
24
10
58
7
12
3
12
10
7
5
6
9
11
8
28
16
.88
.86
.55
.31
.66
.53
.39
.24
.30
.11
.39
.27
.69
.57
.89
.50
.49
204
134
254
302
154
41
152
178
179
152
207
165
209
20
189
58
312
.56
.62
.87
.21
.50
.99
.08
.88
.85
.36
.52
.64
.78
.64
.11
.28
.55
0.33
0.23
0.24
0.57
0.31
0.70
0.20
0.94
0.73
2.74
0.19
0.43
0.78
0.73
0.19
1.23
0.73
ALL
50,440 14.27 171.73 0.66
Indicates a vehicle from the Emission Factor Database.
Analysis of the Super emitters showed that the extremely
high emissions result from failure of the closed-loop control
system. A bad oxygen sensor or a malfunctioning electronic
control unit can often be the problem. . Additionally, many
Super emitters suffer from problems which vehicle tune-ups
often address such as dirty air filters, worn plugs, bad
distributor, etc.
Only one growth rate for all closed-loop technology
vehicles was calculated for Super emitters. Only the
surveillance database was used for determining the rate of
occurrence of Super emitters. Therefore, only nine of the
seventeen Super emitters identified in all sources are used.
The first step in finding the growth rate of Super emitters was
to calculate the fraction of Supers in the sample. The
fraction was then divided by the average mileage of the sample
to obtain the rate of occurrence of Super emitters per 10,000
miles.
The methodology assumes that no Super emitters exist at
zero miles. Also, the rate of occurrence of Supers is assumed
-16-
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to increase linearly with mileage. Unlike the high emitters,
the rate of increase is not assumed to change after 50,000
miles.
2.3
The calculation is:
Number of Supers
Number of Closed-loop
Vehicles in the Sample
or:
(9 / 1238) / 3.3332
General Methodology
Average Mileage Growth
/ of the Closed-loop = of
Sample in 10K Supers
0.00218 = Growth of Supers
The estimates of the vehicle emissions are weighted sums
of the separate emission contributions of Passing, Marginal,
High, and Super emitters. The equation is in the form:
E(M) = (l-Wra-Wh-Ws) * (ZMP+DFP*M)
-1- Wm*(ZMin + DFm*M) + Wh*(ZMh+DFh*M)
+ WS*ZMS
(1)
A set of three estimates, in the form of equation (1), is
generated. The three estimates represent the three
technologies of carbureted, fuel injected, and open loop. They
are then weighted together using the technology distribution
fractions found in Table 2-2 to produce a weighted emission
value (WEV).
Mathematically, the form is:
WEV = I Et(M)
where i = technology type
For each model year, the weighted emission values are
calculated for twenty different vehicle mileage points over the
life of a vehicle. Each point is the average mileage that the
in-use vehicle fleet, of that model year, has at a given age.
Table 2-13 displays the twenty average mileage points, the
vehicle miles traveled fraction (VMT), and the corresponding
vehicle ages. The VMT fraction is the fraction of total travel
which the vehicles of a given age perform in a year. For
example, the vehicles which are two years old, on average, make
up 12% of the total light-duty vehicle VMT.
-17-
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Table 2-13
Age and Mileage Distribution
Age Mileage VMT Fraction
Age Mileage VMT Fraction
1
2
3
4
5
6
7
8
9
10
13,118
26,058
38,298
49,876
60,829
71,190
80,991
90,262
99,031
107,326
0.030
0.120
0.111
0.099
0.088
0.078
0.068
0.060
0.054
0.048
11
12
13
14
15
16
17
18
19
20
115,172
122,594
129,615
136,257
142,540
148,483
154,104
159,421
164,451
169,209
0.043
0.038
0.033
0.028
0.024
0.020
0.017
0.013
0.010
0.019
1.000
For each model year, the twenty technology weighted
emission values are regressed versus mileage to produce an
emission factor. Since the data for HC and CO emission points
are non-linear due to the "kink," two linear regressions are
performed. The first regression is done on the data points
which have mileages from zero to 50,000 miles. This produces
the zero mile level and the first deterioration factor. The
second regression is computed on the data points which have
mileages greater than 50,000 miles. The deterioration of this
regression becomes the second deterioration. The second
regression is constrained to be equal at the 50,000 point of
the first regression. Both regressions are weighted by the VMT
fraction contribution of each age (see Table 2-13). This
allows each emission point to be weighted by the amount of
travel that actually happens at that age. The NOx weighted
emission factors are calculated in a manner analogous to the HC
and CO emission numbers. The difference is that the NOx
regression is not split at 50,000 miles but has only a single
deterioration factor for all mileages. This approach was used
because there were no high NOx emitters.
2.4 Emission Factor Results
The final HC, CO, and NOx emission factors for light-duty
vehicles are shown in Table 2-14. These numbers are used in
the MOBILE4 computer model to predict the exhaust emissions of
1981 and later cars.
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Table 2-14
MOBILE4 Exhaust Emission Factors
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
ZML
.308
.305
.257
.242
.254
.265
.264
.267
.269
.271
.275
.278
ZML
3.378
3.376
2.731
2.431
2.611
2.764
2.720
2.757
2.785
2.813
2.870
2.915
ZML
0.651
0.633
0.632
0.663
0.651
0.641
0.647
0.646
0.644
0.642
0.638
0.635
HC
DET
.079
.074
.062
.067
.063
.060
.060
.059
.059
.058
.057
.056
CO
DET
1.147
1.079
0.760
0.840
0.803
0.771
0 . 786
0.780
0.774
0.769
0.757
0.748
NOx
DET
0.067
0.071
0.039
0.035
0.035
0.035
0.034
0.034
0.034
0.034
0.034
0.034
(qm/mi)
DET2
.108
.101
.085
.088
.084
.081
.081
.080
.079
.078
.077
.076
(qm/mi)
DET2
1.765
1.616
1.013
1.052
1.014
0.982
0.983
0.973
0.967
0.961
0.949
0.939
(qm/mi)
DET2
50k
0.70
0.68
0.57
0.58
0.57
0.56
0.56
0.56
0.56
0.56
0.56
0.56
50k
9.11
8.77
6.53
6.63
6.63
6.62
6.65
6.66
6.66
6.66
6.66
6.66
50k
0.98
0.99
0.83
0.84
0.83
0.82
0.82
0.82
0.81
0.81
0.81
0.80
100k
1.24
1.18
0.99
1.01
0.99
0.97
0.97
0.96
0.96
0.95
0.95
0.94
100k
17.94
16.85
11.60
11.89
11.70
11.53
11.57
11.52
11.49
11.46
11.40
11.35
100k
1.32
1.34
1.02
1.02
1.00
1.00
0.99
0.98
0.98
0.98
0.98
0.97
-19-
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3.0 INSPECTION AND MAINTENANCE BENEFITS
Three I/M tests are modeled by the MOBILE4 Tech IV Credit
Model. They are the Idle test, the 2500/Idle test, and the
Loaded/Idle test performed on a dynamometer. The I/M tests are
much more likely to fail High and Super emitting cars than
Marginal or Passing emitters. This fact is used in I/M
programs to identify vehicles which most need repair and
produce the greatest emission benefits.
The MOBILE4 Tech IV Credit Model only uses the cutpoints
of 1.2% CO and 220 ppm HC. The previous Tech IV Credit Model
for MOBILE3 also produced I/M credits for the cutpoints of 0.5%
CO and 100 ppm HC, and 3.0% and 300 ppm HC. These cutpoints
were dropped because they were rarely used by state I/M
programs.
The I/M credits produced by the MOBILE4 Tech IV Credit
Model are the product of identification effectiveness of a
particular I/M test (IDR) and the effectiveness of repair after
identifying a failing vehicle. The EPA surveillance database
was used to generate the IDR's for each test and emitter type.
A separate repair effectiveness database was used to estimate
the effect of repairing each emitter type after it failed the
I/M procedure.
3.1 Short Test Data
The Idle test tailpipe emission levels were gathered
mainly from the second idle in neutral of the four-mode test
procedure. In this procedure the vehicle is tested at curb
idle, then with the idle speed held at 2500 rpm for up to 30
seconds, then at curb idle again, and finally at curb idle with
the vehicle transmission in drive with the brake on for
vehicles with automatic transmissions. The second idle
measured in this procedure best simulates a preconditioned Idle
test procedure.
The 2500/Idle test data for this analysis were derived
mainly from the same four-mode test procedure. In this case
the emissions sampled at 2500 rpm and from the second idle in
neutral are used. Vehicles must pass both the 2500 rpm and
idle modes of this test. For MOBILE4 the I/M credit is based
on a different definition of the 2500/Idle test than in
MOBILES. In the new definition, the CO outpoint of 1.2% is
applied during the idle portion of the test but not during the
2500 rpm test portion. The additional 2500 rpm benefits of the
2500/Idle test over the idle test alone are therefore based
only on the HC cutpoint of 220 ppm. This change reduces the
amount of emission credit given the 2500/Idle test. This
change in the 2500/Idle test procedure is being promoted by EPA
to reduce problems with testing vehicles which purge their
-20-
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evaporative canisters at 2500 rpm. Many of these vehicles tend
to fail the CO cutpoint during the 2500 rpm portion of the test
even though the FTP emissions are low.
Restart test procedure results were substituted for the
above four-mode test data for all vehicles manufactured by the
Ford Motor Company in the sample with restart procedure
results. The Restart test is a modified 2500/Idle test in
which the vehicle ignition is turned off and then restarted
prior to the 2500 rpm portion of the test, and is required for
Ford vehicles to be eligible for warranty coverage.
The data on the Loaded/Idle test procedure came primarily
from some limited testing done on 1981, 1982 and 1983 model
year vehicles. Where Loaded/Idle data were not available, the
2500/Idle data were substituted. The Loaded/Idle test
procedure consisted of a 30 MPH cruise with a 9.0 hp load for
30 seconds followed by a 30 second idle period. Emissions are
sampled during both modes and vehicles must pass both the
loaded and idle modes of this test.
3.2 Identification Rates
Table 3-1 below displays the distribution in the EPA
surveillance database of emitter type versus technology. These
vehicles were used to generate the I/M identification of excess
emissions rates (IDR's) as well as the emission factors. The
tampered vehicles are shown for illustration only. They were
not used in the analysis to create the I/M benefits.
Table 3-1
Emitter Category vs. Technology
in the EPA Surveillance Database
Sample GARB FI PL Total
Pass FTP 408 198 172 778
Marg 306 176 253 735
High 93 48 34 175
Super 6208
Tampered 53 12 24 89
Total 866 436 483 1785
One vehicle, a Super emitter, was eliminated from the
sample for purposes of determining short test identification
rates. This vehicle, number 5206, was determined to have
unreliable short test results making it impossible to determine
if the vehicle would be correctly identified. Since it was a
Super emitter, any determination would greatly effect the
emission reduction estimates for short tests. Eliminating this
-21-
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vehicle from the identification rate sample avoids any effect
this vehicle would have without reducing the confidence in the
results using the remaining vehicles in the sample.
Table 3-2 shows the failure distribution by emitter type
for the Idle test, the 2500/Idle test and the Loaded/Idle test
in the EPA Surveillance Database. Note that the I/M short test
failure rate increases with increased FTP emissions. Also,
that tampered vehicles tend to fail at a higher rate than the
fleet as a whole, but not as much as the vehicles classified as
High emitters.
Table 3-2
Identification Rate Database
Idle Test 2500/Idle Test Loaded/Idle Test
Sample Pass Fail % Fail Pass Fail % Fail Pass Fail % Fail
Pass 768 10 1.3 766 12 1.5 763 15 1.9
Marginal 709 26 3.5 707 28 3.8 699 36 4.9
High 128 47 26.9 123 52 29.7 112 63 36.0
Super 3 5 62.5 3 5 62.5 2 6 75.0
Tampered 77 12 13.5 76 13 14.6 73 16 18.0
Total 1685 100 5.6 1675 110 6.2 1649 136 7.6
Table 3-2 presents the raw I/M failure rates for various
I/M short tests. These rates were easily calculated by
dividing the number of failures by the sample size. It shows
that a high percent of the failures are high emitters.
The MOBILE4 Tech IV Model, however, uses a measure of the
total emissions of the vehicles identified by the short test to
quantify the impact of I/M. This IDR is usually greater than
the simple failure rate shown in Table 3-2 and can be different
for HC and CO. The IDR better reflects the fact that short
tests usually identify the worst emitting vehicles in any
grouping. For MOBILE4, the IDR was determined as the fraction
of the emissions in excess of certification standards.
Table 3-3 shows there to be large differences between the
IDR's of High emitters and Marginal emitters. For example, the
High emitters make up about 10% of the sample; however, it is
these vehicles at which I/M programs are targeted and which
contribute the bulk of the emissions reductions. Also, the
IDR's of the High and Super emitting fuel injected vehicles are
considerably lower than the corresponding ones for carbureted
or open-loop vehicles. The primary cause of this phenomenon is
the low failure rate of fuel injected vehicles compared to
carbureted vehicles, even among High emitting vehicles.
-22-
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Vehicles passing the FTP, by definition, have no excess
emissions. Therefore, the IDR for Passing vehicles is zero in
all cases. The IDR for Super vehicles were determined from the
combined carbureted and fuel injected sample of eight Super
emitting vehicles.
Table 3-3
Identification Rates For Excess Emissions
Pass FTP
Marginal
High
Super
Carbureted Vehicles
Idle Test
HC
CO
0.00 0.00
3.34 1.51
35.74 41.24
55.26 71.72
2500/Idle Test
HC CO
0.00
3.34
42.90
55.26
0.00
1.51
49.90
71.72
Loaded/Idle Test
HC CO
0.00
5.71
53.99
58.63
0.00
5.36
63.76
84.90
Pass FTP
Marginal
High
Super
Fuel Injected Vehicles
Idle Test
HC
CO
0.00 0.00
7.46 8.33
15.57 23.74
55.26 71.72
2500/Idle Test
HC CO
0.00
8.30
18.93
55.26
0.00
8.60
25.80
71.72
Loaded/Idle Test
HC CO
0.00
11.29
18.93
58.63
0.00
12.54
25.80
84.90
Pass FTP
Marginal
High
Super
Open Loop Vehicles
Idle Test 2500/Idle Test
HC CO
HC
CO
0.00 0.00
3.80 4.86
60.61 61.14
0.00
5.20
71.57
0.00
6.90
77.47
Loaded/Idle Test
HC CO
0.00
4.55
66.22
0.00
9.25
75.82
3.3 Repair Effects from I/M
In the MOBILES Tech IV Credit Model, the I/M benefits
were based on the assumption that High and Super emitters would
fail the I/M test and a certain percentage of the excess
emissions would be identified and repaired. It was assumed
that this repair would reduce the emissions of a High emitting
-23-
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vehicle to those of the average Normal emitting vehicle. This
assumption was necessary because there were insufficient data
available to show the effect of failing an I/M test and
receiving repairs to pass it.
3.3.1 Repair Database
Prior to the development of the MOBILE4 Tech IV Model,
testing programs were conducted with vehicles which went
through the I/M process and were repaired by either commercial
garage mechanics or by EPA contractor mechanics. Data
collected from these programs allow the modeling of repair
effectiveness for the MOBILE4 Tech IV Model. Table 3-4 shows
the distribution of the repair effects by testing program
type. Approximately half of the repair effectiveness database
is composed of vehicles which are in the EPA Surveillance
Database and had before and after repairs and emission tests.
Approximately, one quarter of the vehicles were recruited after
they failed the Maryland or Washington, D.C. I/M programs and
were repaired by EPA contractor mechanics or garage mechanics
in Washington D.C. to pass the I/M test. The other 25% of the
vehicles were involved in an extensive I/M evaluation program
conducted by the California Air Resources Board. The results
from this program may be the most representative of actual
field conditions in decentralized programs, since the vehicles
were tested and repaired in commercial garage facilities.
Table 3-4
The Distribution of Repair Database
Vehicles by Emissions Testing Program
Program tt of Vehicles %
EF80 34 4.7
EF82 280 38.7
MI82 28 3.9
SP82 8 1.1
IM83 184 25.4
CALI87 190 26.2
ALL 724 100.0
Tables 3-5 and 3-6 show the distribution of vehicles in
the repair database by model year, technology, and emitter
category. As Table 3-5 shows, 51 1980 model year vehicles from
California were included in the database and in the analysis of
repair effects. These vehicles were included because they were
certified to California's strict 1980 standards. They also
used technology which was similar to what was on Federally
certified 1981 model year vehicles.
-24-
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Table 3-5
Distribution of Repair Database
Vehicles by Model Year and Technology
Technology Type
Model Year GARB FI OL
1980* 42 90
1981 242 20 106
1982 50 38 17
1983 37 55 26
1984 26 25 8
1985 592
1986 0 7 0
402 163 159
Includes only California cars.
Table 3-6
Distribution of Repair Database
Vehicles by Emitter Category and Technology
Technology Type
Emitter Type CARS FI OL
Pass FTP 48 23 13
Marg 161 40 75
High 177 91 71
Super 16 9 0
ALL 402 163 159
3.3.2 Emission Reduction from Repairs
Table 3-7 displays the emission reductions from repairing
vehicles which failed the initial idle test but passed after
repairs. The data show that the emissions from failing Highs
can be reduced more than 50% as a result of I/M repairs. The
benefit of repairing Marginal and Passing emitters which fail
I/M drops off sharply, with emissions actually increasing after
repairing vehicles under certification standards in many
cases. Table 3-8 displays analogous results for vehicles which
fail the 2500/Idle test.
-25-
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Pass FTP
Marginal
High
Super
Pass FTP
Marginal
High
Super
Pass FTP
Marginal
High
Super
Table 3-7
Failed Initial Idle Test/Pass After Repair
_N
4
34
53
9
_N
3
9
24
4
N
0
5
30
0
Carbureted Vehicles
Before
0.368
0.806
2.858
13.811
Before
0.260
0.455
2.358
6.405
Before
0.660
2.477
HC
After
%Reduct
Before
0.385 -4.62 5.120
0.645 19.98 9.205
1.398 51.08 50.939
2.146 84.46 190.210
Fuel Injected Vehicles
HC
After
0.300
0.333
0.936
1.928
Open
HC
After
0.523
1.038
%Reduct
Before
15.38 3.443
26.81 6.535
60.31 47.898
69.90 184.070
Loop Vehicles
%Reduct
20.76
58.09
Before
7.900
43.638
CO
After
5.333
7. 136
21.895
16.206
CO
After
4.330
4.443
15.163
45.067
CO
After
4.963
13.828
%Reduct
-4.16
22.48
57.02
91.48
%Reduct
-25.76
32.01
68.34
75.52
%Reduct
37. 18
68.31
-26-
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Pass FTP
Marginal
High
Super
Table 3-8
Failed Initial Two Speed Test/Passed After Repairs
Carbureted Vehicles
_N
5
38
58
10
Pass FTP 3
Marginal 9
High 25
Super 4
Pass FTP
Marginal
High
Super
_N
0
6
31
0
Before
0.320
0.739
2.833
11.492
Before
0.220
0.455
2.340
6.547
Before
0.643
2.506
HC
After
IReduct
Before
0.360 -12.50 4.303
0.591 20.03 8.661
1.189 58.03 49.632
1.931 83.20 183.340
Fuel Injected Vehicles
HC
After
0.265
0.333
0.861
0.603
Open
HC
After
0.550
0.966
%Reduct
Before
-20.45 3.580
26.81 6.535
63.21 47.205
90.79 192.02
Loop Vehicles
%Reduct
14.46
61.45
Before
11.385
43.749
CO
After
5.530
6.780
17.789
20.915
CO
After
4.525
4.443
12.801
5.033
CO
After
7.958
11.821
%Reduct
-28.51
21.72
64.16
88.59
%Reduct
-26.40
32.01
72.88
97.38
%Reduct
30.10
72.98
-27-
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3.4 General Methodology
For MOBILE4, the effect of I/M immediately after an
inspection/repair event is calculated by reducing the average
emissions of the Super, High, and Marginal emitting vehicles
stratified by technology, by a percentage which is the product
of the IDR rate and the repair effectiveness. This product is
multiplied by the weighted emission value to create a weighted
I/M emission value for each technology. The I/M emission
values for each technology are then weighted together using the
technology distribution for each model year in Table 2-2. This
produces intermediate I/M emission values for each pollutant,
test type, model year and age. These emission values are
compared to the corresponding non-I/M emission levels to
produce the final I/M credits. This method is somewhat
different from MOBILES where each pre-inspection point was
calculated from the previous post-inspection point assuming an
icreased rate of deterioration.
3.4.1 Annual I/M Credits
The individual credits are generated by comparing the
emissions from all vehicles of a model year with and without
the I/M program. Unfortunately, single emission values for
both I/M and non-I/M cases cannot be used directly.
One problem is the distribution of ages within a model
year. For example, if a program is evaluated in January, 1990,
inspecting the 1988 model year vehicles, the age distribution
of the 1988 model year vehicles would range from 2.25 years to
1.25 years. The vehicles between one and two years old have
only been inspected once. Any vehicles two years and older
should have already received their second inspection. For
purposes of modeling, all vehicles are assumed to be inspected
on the first anniversary of their purchase and periodically
therafter, always on that same date. It is also assumed that
sales of vehicles in a model year are evenly distributed and
that all sales occur exactly in the 12 month period from
October of the calendar year previous to the model year through
September of the next year. In this example, 25% of the
emissions on the evaluation date come from vehicles recently
completing their second inspection and 75% of the emissions
come from vehicles which have been inspected only once.
Another factor which is taken into account is the
deterioration of the vehicles in between their yearly
inspections and repairs. Existing evidence suggests that the
type of problems which cause I/M failures can re-occur as often
in the repaired vehicles as they do in the unrepaired fleet.
It is assumed that the fleet, after repairs, will have the same
emission deterioration as before repairs. On the other hand,
there is no reason to suspect that replacement of components
and other types of repairs performed on failed vehicles should
-28-
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be more susceptible to subsequent deterioration than in the
non-I/M fleet. The available data from the California I/M
Review Study are very limited, but suggest no unusual
deterioration after repair. In MOBILES the deterioration
between I/M cycles was calculated to be greater than or equal
to the non-I/M deterioration.
Figure 3-1 shows how the distribution of a model year by
individual age and the deterioration are incorporated to
produce the I/M credits for each age for a given model year.
The upper line is an example of an emission factor found in
Table 2-14. It is the emission factor regression equation
without I/M effects. The lower "sawtooth" figure is the I/M
line. The "sawtooth" illustrates the effect of I/M inspection
and repair and the subsequent deterioration of the fleet. All
deterioration slopes are parallel. The repair effect is
represented by the sudden drop in emission level at each
anniversary. This drop is the product of the identification
rates shown in Table 3-3. and the repair effectiveness in Tables
3-7 and 3-8. Details on these rates can be found in previous
sections. The heavy shaded portions of the lines illustrate
how an I/M credit for the given model year at age two is
produced. MOBILE4 always chooses January 1st as the evaluation
date. The vehicles sold from October through December are
represented by the short line segment to the right of the two
year anniversary point, representing vehicles in the model year
that are older than two years. The longer line segment to the
left of the anniversary point represents the vehicles sold from
January through September, which are still less than two years
old at the evaluation date. The weighted average of each
segment is calculated and the percent difference between the
two weighted averages is computed. This percent difference is
the I/M credit.
3.4.2 Biennial I/M Credits
The weighted emission values after an inspection/repair
event with and without biennial I/M are the same as those for
annual I/M. The only difference is that the biennial I/M
values are applied every other year and that there is
consequently a longer period of deterioration between I/M
inspections and repairs. Figures 3-2 and 3-3 are analogous to
Figure 3-1. Figure 3-2 is an example of a 1-3-5 biennial
program in which a vehicle is first inspected when it is one
year old and then every two years thereafter. Figure 3-3
illustrates a 2-4-6 biennial program which begins when a
vehicle is two years old and inspects it every other year. The
differences are small for a fleet that has a full complement of
vehicle ages. The final biennial credits used in MOBILE4 are
the average of these two program types. This adequately
represents either the 1-3-5 or the 2-4-6 plan, or any mixed
biennial program in which half of each model year is inspected
during each calendar year.
-29-
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3.4.3 Idle I/M Credits
The previous emission factor model (MOBILES) included
idle emission factors in grams/hour but not I/M credits at
idle. - For MOBILE4 it was desired to include I/M credits at
idle; however, very little data were available to evaluate the
effect of I/M on idle emissions. Therefore, the FTP I/M
Credits, as discussed in previous sections, are applied in
MOBILE4 to the idle emission factors to calculate an I/M impact.
-30-
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4.0 NORMALIZED BAG FRACTIONS
The basic exhaust emission level of a vehicle is a
composite derived by VMT-weighting the vehicle's cold start,
stabilized, and hot start emissions. A weighting factor of
20.6% is used for cold start, 52.1% for stabilized, and 27.3%
for hot start. These are the weightings of the three "bags" of
the Federal Test Procedure (FTP) . These bag correction factors
are used in MOBILE4 to adjust the emissions for cold/hot
operation. The bag correction factors are used to separate the
basic emission rate (BER) into cold start, stabilized and hot
start operation emission levels. This correction factor is
defined as:
The basic exhaust emission rate for one of the operating
modes (cold, stabilized, hot) is expressed as:
BERt = BERftp * CF(mile) (1)
Where: BERt is the basic exhaust rate for an individual
bag of the FTP.
p is composite FTP emission factor
CF(mile) is the overall bag correction factor, which
is a function of mileage.
The correction factor CF(mile) is represented in the form:
CF(mile) = At + B4 * M (2)
AI = The zero-mile bag correction factor for bag i.
Bi = The deterioration bag correction factor for bag i.
M = The mileage, in 10,000 mile increments (mile/10,000).
The correction factor equation can also be displayed in
terms of the zero-mile and deterioration levels. For 1981 and
newer model year gasoline fueled passenger cars, the model
produces a zero-mile level and deterioration rate for vehicles
with mileage less than 50,000 and a second deterioration rate
for vehicles with greater than 50,000 miles. The zero-mile and
deterioration rates are calculated for each model year, FTP
bag, and pollutant (HC and CO only ; NOx does not have the
second deterioration) .
-31-
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The form of the equation when the mileage is less than
50,000 is:
Bt*M = (ZMt+DR^M) / (ZMf t p+DRf t P*M) (3)
Where:
ZMt = The zero-mile coefficient for bag i (calculated by
the emission factor model).
DRi = The first deterioration rate (0-50K miles) for bag i.
ZMftp = The zero-mile coefficient for the composite FTP
This coefficient is constructed from a weighted
average of the three FTP bags.
DRftp = The deterioration rate (0-50K miles) for the
composite FTP. This coefficient is also constructed
from a weighted average of the three FTP bags.
M = The mileage, expressed in 10K increments
(mile/10,000) up to 50,000 miles.
Equation 3 can be separated and the following four
equations are the result.
A4 = ZMt / (ZMftp + DRftp * M) (4)
or
Ai = (ZMt/ZMftp) / (1 + (DRftp/ZMftp)*M)) (5)
B4*M = (DRt*M) / (ZMftp + DRftp*M) (6)
or
BA*M = (DRt/ZMftp) / (1 + (DRrtp/ZMftp)*M) (7)
The bag correction factors for vehicles with mileages
greater than 50,000 are similar to the previous ones. The
equations are the same except ZM4 is now ZM1Sox, ZMftp is
ZMftpsok, DRt is now DR1Sok and DRftp is now
DRftpsok- Also, the variable (M) is the mileage greater than
50,000 miles.
(ZM1Sok+DRisok*M)
A1Sok+B1Sok*M = -------------------------- (8)
(ZMftpsok +DR f t P s o k *M )
-32-
-------
The variables ZMtsok and ZMftpSok are not zero-mile
levels but the 50,000 mile emission levels of bag i and the
composite FTP emission level for a given pollutant. The
variables (DRjsok) and (DRftpSok) are the rates of
deterioration in emissions which vehicles experience after
50,000 miles in bag i and the composite FTP emissions
respectively. The bag fraction equations for vehicles with
mileages greater than 50,000 are then:
isok / ZMft
A1
Sok
and
BI
S Ok
(DRrtpSOk / ZMftp)*M))
(DRtSok/ZMftp)
+ (DRftp/ZMftp)*M)
(9)
(10)
The bag correction factors can also be represented as
normalized bag fractions. In this form the three correction
factors sum to 1.0 and are used in MOBILE4 . Mathematically the
equation is:
1.0
+ Bi*M)/(Aftp + Bftp*M))
(11)
where vmfi is the percent of the vehicle miles traveled (vmt)
contributed by each of the three modes - cold start, hot
stabilized, and hot start. The default values for the three
percents are 20.6%, 52.1%, and 27.3% respectively. In the
MOBILE4 model these percentages can also be entered by the user
in the scenario record.
Equation (11) can be expanded to:
1.0 =
(l-w-x)*(A2+B2*M) + x*(A3+B3*M)
Aftp + Bftp * M
where vmfi becomes variables (w), (x) or (l-w-x). Variable
(w) is the fraction of the miles a vehicle travels in cold
start (default = 0.206). Variable (x) is the fraction traveled
in the hot start mode (default = 0.273) and remaining fraction
(l-w-x) is the fraction of hot-stabilized travel (default =
0.521).
-33-
-------
The three normalized bag fractions are the terms of this
equation. For example, the normalized fraction for bag one for
mileage under 50,000 miles is:
BFi = w*(A, + B,*M) / (Aftp + B,tp*M) (13)
For bags two and three the equations are:
BF2 = w*(A2 + B2*M) / (A,t, + Bftp*M) (14)
and
BF3 = w*(A, + B,*M) / (Aftp + Bftp*M) (15)
Normalized bag fractions for mileages over 50,000 miles
are generated in an analogous manner substituting At so*/
Bisok/ Aftpsok and Bftpsok for the appropriate variable.
-34-
-------
5.0 HIGH ALTITUDE
5.1 Emission Factors
The number of vehicles available for analysis which were
tested at high altitudes make an analysis, like the one
performed for low altitude passenger cars, impossible. In
addition, changes in the standards for high altitude areas make
further division of the database necessary. Passenger cars
must now meet the same emissions standards at all altitudes.
As a result, the modeling approach was simplified. It is
assumed that passenger cars emissions at high altitude will
deteriorate at the same rate as low altitude vehicles.
Analysis of the limited high altitude sample supports this
concept for low mileages. Average emission levels and mileages
were determined for each model year. The small samples of 1983
and 1984 model year vehicles were combined. Using the low
altitude emission deterioration rates and the high altitude
mean emissions and mileages, the zero mile emission levels were
determined. If this emission level was less than the low
altitude prediction, the high altitude emissison level was set
to the low altitude prediction. The 1986 and newer model years
use the results of the combined 1984 and 1985 sample.
Table 5-1
High Altitude Sample
Model Sample Average Emissions (gm/mi) Average
Year Size HC CO NOx Mileage
1981 176 .633 13.522 .563 8,627
1982 149 .642 12.596 .815 26,451
Combined 106 .338 4.399 .841 14,723
1983-84
-35-
-------
Table 5-2
Passenger Car (LDGV) High Altitude
Exhaust Emission Factors for MOBILE4
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
Model
Year
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992+
HC (qm/mi)
ZML
.565
.446
.269
.242
.254
.265
.264
.267
.269
.271
.275
.278
ZML
12.532
9.742
3.280
3. 162
3.217
3.264
3.242
3.251
3.259
3.267
3.284
3 . 298
ZML
.505
.627
.784
.789
.789
.789
.791
.791
.791
.791
.791
.791
DET
.079
.074
.062
.067
.063
.060
.060
.059
.059
.058
.057
.056
DET
1.147
1.079
.760
.840
.803
.771
.786
.780
.774
.769
.757
.748
NOx
DET
.067
.071
.039
.035
.035
.035
.034
.034
.034
.034
.034
.034
DET2
.108
.101
.085
.088
.084
.081
.081
.080
.079
.078
.077
.076
CO (qm/mi)
DET2
1.765
1.616
1.013
1.052
1.014
.982
.983
.973
.967
.961
.949
.939
(qm/mi)
50k
0.84
0.98
0.98
0.96
0.96
0.96
0.96
0.96
0.96
0.96
0.96
0.96
50k
0.96
0.82
0.58
0.57
0.57
0.56
0.56
0.56
0.56
0.56
0.56
0.56
50k
18.27
15.14
7.08
7.36
7.23
7.12
7.17
7.15
7.13
7.11
7.07
7.04
100k
1.18
1.34
1.17
1.14
1.14
1.14
1.13
1.13
1.13
1.13
1.13
1.13
100k
1.50
1.32
1.00
1.01
0.99
0.97
0.97
0.96
0.96
0.95
0.95
0.94
100k
27.10
23.22
12.15
12.62
12.30
12.03
12.09
12.02
11.97
11.92
11.82
11.74
-36-
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5.2 High Altitude I/M Credits
A separate model was not developed to generate high
altitude I/M credits for model year vehicles 1981 and newer.
However, since the technologies and emission levels at high and
low altitudes are quite similar, it was assumed that the
credits developed for low altitude could be applied directly to
the high altitude emission estimates. Separate high altitude
I/M credits are necessary for pre-1981 model year vehicles in
MOBILE4.
5.3 High Altitude Bag Fractions
Different Bag Fractions for high altitude modeling were
not developed for MOBILE4 because the technologies and emission
levels for both altitudes are very similar. Therefore, the bag
fractions developed for low altitude will be applied at high
altitude.
-37-
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MOBILE4
Exhaust Emission Factors and Inspection/Maintenance
Benefits for Passenger Cars
Appendix
Program Code Listing
-38-
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1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
CC
CC.
CC
CC.
CC
CC.
CC
CC
,
c
CC
CC.
CC
CC.
CC.
CC.
CC
CC
CC
CC.
CC
CC
CC
CC.
CC
CC
.MOBILE4 I/M Credit Model for 1981 and newer LDGV
.Program Main
.COMMON Blocks and DIMENSION Statements
COMMON /DAT01/ MYR, ISTD, ITECH, IBAG, IP, IAGE, ICUT, ITST
COMMON /DAT02/ AMIL (20) , ODOM (20) , TMILE (20) , WGT (20)
COMMON /DAT03/ PASS (20, 3, 2) , EDGE (20, 3, 2) , HIGH (20, 3, 2)
COMMON /DAT04/ FAIL (20, 3, 2)
COMMON /DAT05/ SNO (3, 2) , SMO (3, 2)
COMMON /DAT06/ FRAC(3,12)
COMMON /DAT07/ ESO (2 , 4, 3, 2) , EHO (2, 4 , 3, 2 )
COMMON /DAT08/ DM (2, 4, 3, 2), DN (3, 4, 3, 2)
COMMON /DAT09/ ZMIL (2, 4, 3, 2) , CWO (2, 4, 20, 3, 2) , CIMW (2, 4, 20, 3, 2, 3)
COMMON /DAT10/ EWO (2 , 4 , 20 , 12) , EIMW (2 , 4 , 20 , 12 , 3) , EZM (2 , 4 , 12 )
COMMON /DAT11/ CREDIT (2, 20 , 12, 3 , 4)
COMMON /DAT12/ ZML (3, 4, 12) , ZML1 (3, 4, 12) , ZML2 (3, 4, 12)
COMMON /DAT13/ BFZML1 (3, 4, 12) , BFDET1 (3, 4, 12)
COMMON /DAT14/ DET (3, 4 , 12) , DET1 (3, 4 , 12) , DET2 (3, 4 , 12)
COMMON /DAT16/ XSIDR (2, 3, 2, 3) , XHIDR (2, 3, 2, 3)
COMMON /DAT17/ RSUP (2,3,2,3) , RHIG (2, 3, 2, 3)
COMMON /DAT18/ SUPER (20 , 3, 2)
COMMON /DAT19/ GM (3, 2) , GH (3, 2) , GS (3, 2) , BEND (3, 2)
COMMON /DAT20/ EMO (2, 4, 3, 2) , ENO (3, 4, 3, 2)
COMMON /DAT21/ BFDET2 (3, 4 , 12) , BFZML2 (3, 4 , 12 )
COMMON /DAT22/ RMAR (2, 3, 2, 3)
COMMON /DAT24/ XMIDR (2, 3, 2 , 3)
INTEGER BI
OPEN(1,FILE='BIENIAI/ )
OPEN(7,FILE='ANNUAL' )
OPEN(8,FILE='EFAC' )
OPEN(9,FILE='BAGFRAC' )
.Inspection Frequency:
.BI = 1 1/3/5 Biennial inspection schedule.
.BI = 2 2/4/6 Biennial inspection schedule.
. BI = 3 Annual inspection schedule.
BI = 3
.Calculate the mileage accumulated in each one year interval.
AMIL(l) = ODOM(l)
DO 10 IAGE=2,20
AMIL (IAGE) = ODOM (IAGE) - ODOM ( IAGE- 1)
10 CONTINUE
.CO standard ( 1: 1981,1982, 2: 1983 and newer )
DO 600 ISTD=1,2
-39-
-------
1058
'1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
TO 8 5
1086
1087
1088
1089
1090
1091
1092
CC..ITECH indicates the technology type used in the vehicles,
CC
CC..ITECH = 1 : Closed-Loop, Carbureted
CC..ITECH = 2 : Closed-Loop, Fuel-Injected
CC..ITECH = 3 : Open-Loop, Any
CC
DO 600 ITECH=1,3
CC
CC..Vehicle age in years
CC
DO 600 IAGE=1,20
CC
CALL SIZE
CC
CC..FTP Bag ( 1=FTP; 2=BAG1; 3=BAG2; 4=BAG3 )
CC
DO 600 IBAG=1,4
CC
CC..Pollutant ( 1:HC, 2:CO )
CC
DO 600 IP=1,2
CC
CC
CALL EMIT
CALL IMEMIT
600 CONTINUE
CALL MYRSUB
CALL REGR
CALL JAN1
CALL OUTPUT
CC
CC
STOP
END
-40-
-------
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
SUBROUTINE SIZE
.This routine predicts the number of vehicles in each emission
.level category by technology and age.
COMMON /DAT01/ MYR,ISTD,ITECH,IBAG,IP,IAGE,ICUT,ITST
COMMON /DAT02/ AMIL(20),ODOM(20),TMILE(20),WGT(20)
COMMON /DAT03/ PASS(20,3,2),EDGE(20,3,2),HIGH(20,3,2)
COMMON /DAT04/ FAIL(20,3,2)
COMMON /DAT05/ SNO(3,2),SMO(3,2)
COMMON /DAT18/ SUPER(20,3,2)
COMMON /DAT19/ GM(3,2),GH(3,2),GS(3,2),BEND(3,2)
.Estimate the number of FTP failures
FAIL(IAGE,ITECH,ISTD) = SMO(ITECH,ISTD)
* + GM(ITECH,ISTD)*ODOM(IAGE)
IF(FAIL(IAGE,ITECH,ISTD).GT.1.0) FAIL(IAGE,ITECH,ISTD)=1.0
.Calculate the number of "HIGH" emitting vehicles
HIGH(IAGE,ITECH,ISTD) = GH(ITECH,ISTD) * ODOM(IAGE)
."BEND" is the change in the rate of occurrance of "HIGH"
.emitting vehicles assumed to occur at 50,000 miles.
IF(ODOMdAGE-l) .GT.5.0)
* HIGH(IAGE,ITECH,ISTD) = HIGH(IAGE-1,ITECH,ISTD)
* + BEND(ITECH,ISTD)*GH(ITECH,ISTD)*AMIL(IAGE)
IF (HIGHdAGE, ITECH, ISTD) .GT. 1.00) HIGH (IAGE, ITECH, ISTD) =1.00
.Calculates the number of "SUPER" emitting vehicles
SUPER(IAGE,ITECH,ISTD) = GS(ITECH,ISTD)*ODOM(IAGE)
IF(SUPER(IAGE,ITECH,ISTD).GT.1.0) SUPER(IAGE,ITECH,ISTD)=1.0
.Calculate the number of "MARGINAL" FTP failures
EDGE(IAGE,ITECH,ISTD) = FAIL(IAGE,ITECH,ISTD)
* - HIGHdAGE, ITECH, ISTD)
* - SUPER(IAGE,ITECH,ISTD)
IF(EDGE(IAGE,ITECH,ISTD).LT.0.0) EDGE(IAGE,ITECH,ISTD)=0.0
.Calculate the number of remaining FTP passing vehicles
CHECK = HIGHdAGE, ITECH, ISTD) + SUPER (IAGE, ITECH, ISTD)
IF (CHECK.GT.1.0)
* HIGHdAGE, ITECH, ISTD) = 1.0 - SUPER (IAGE, ITECH, ISTD)
PASS(IAGE,ITECH,ISTD) =1.0
- EDGE(IAGE,ITECH,ISTD)
- HIGH(IAGE,ITECH,ISTD)
- SUPER(IAGE,ITECH,ISTD)
IF(IAGE.GT.l) GOTO 999
.Calculates the remaining FTP passing vehicles at zero miles
-41-
-------
2058 SNO(ITECH,ISTD) = 1.0 - SMO(ITECH,ISTD)
2059 CC
2060 999 RETURN
2061 END
-42-
-------
3000
3001
3002
3003
3004
3005
3006
3007
3008.
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
SUBROUTINE EMIT
..This routine combines the emission levels of each emission
..category based on the predicted categroy size.
COMMON /DAT01/ MYR, ISTD, ITECH, IBAG, IP, IAGE, ICUT, ITST
COMMON /DAT02/ AMIL (20) , ODOM (20) , TMILE (20) , WGT (20)
COMMON /DAT03/ PASS (20, 3, 2) , EDGE (20, 3, 2) , HIGH (20, 3, 2)
COMMON /DAT05/ SNO (3, 2) , SMO (3, 2)
COMMON /DAT07/ ESO (2, 4, 3, 2) , EHO (2, 4, 3, 2)
COMMON /DAT08/ DM (2, 4, 3, 2) , DN (3, 4, 3, 2)
COMMON /DAT09/ ZMIL (2, 4, 3, 2) , CWO (2, 4, 20, 3, 2) , CIMW (2, 4, 20, 3, 2, 3)
COMMON /DAT18/ SUPER (20, 3, 2)
COMMON /DAT19/ GM (3, 2) , GH (3, 2) , GS (3, 2) , BEND (3, 2)
COMMON /DAT20/ EMO (2 , 4 , 3, 2) , ENO (3, 4 , 3, 2)
IF (IAGE.GT. 1) GOTO 10
..Emission levels at zero mileage point
ZMIL (IP, IBAG, ITECH, ISTD) =
* SMO (ITECH, ISTD) * EMO (IP, IBAG, ITECH, ISTD)
* + SNO (ITECH, ISTD) * ENO (IP, IBAG, ITECH, ISTD)
..Emission levels by age
10 ES = "ESO (IP, IBAG, ITECH, ISTD)
EH = EHO (IP, IBAG, ITECH, ISTD)
* + ( DM (IP, IBAG, ITECH, ISTD) *ODOM (IAGE) )
EM = EMO (IP, IBAG, ITECH, ISTD)
* + ( DM (IP, IBAG, ITECH, ISTD) *ODOM( IAGE) )
EN = ENO (IP, IBAG, ITECH, ISTD)
* + ( DN (IP, IBAG, ITECH, ISTD) *ODOM( IAGE) )
..Calculate the base' (without I/M) composite emission levels by age
CWO (IP, IBAG, IAGE, ITECH, ISTD) =
* PASS (IAGE, ITECH, ISTD) * EN
* + EDGE (IAGE, ITECH, ISTD) * EM
* + HIGH (IAGE, ITECH, ISTD) * EH
* + SUPER (IAGE, ITECH, ISTD) * ES
999 RETURN
END
-43-
-------
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
CC
cc
CC
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
SUBROUTINE IMEMIT
.This routine combines the emission levels of each emission
.category based on the predicted catagory size.
COMMON /DAT01/ MYR,ISTD,ITECH,IBAG,IP,IAGE,ICUT,ITST
COMMON /DAT02/ AMIL(20),ODOM(20),TMILE(20) , WGT(20)
COMMON /DAT03/ PASS(20,3,2),EDGE(20,3,2),HIGH(20,3,2)
COMMON /DAT07/ ESO(2,4,3,2),EHO(2,4,3,2)
COMMON /DAT08/ DM(2,4,3,2),DN(3,4,3, 2)
COMMON /DAT09/ ZMIL(2,4,3,2),CWO(2,4,20,3, 2),CIMW(2,4,20,3,2,3)
COMMON /DAT16/ XSIDR(2,3,2,3) , XHIDR(2, 3, 2, 3)
COMMON /DAT17/ RSUP(2,3,2, 3),RHIG(2,3,2,3)
COMMON /DAT18/ SUPER(20,3,2)
COMMON /DAT20/ EMO(2, 4,3,2),ENO(3,4,3,2)
COMMON /DAT22/ RMAR(2, 3, 2, 3)
COMMON /DAT24/ XMIDR(2,3, 2, 3)
,Non-I/M emission levels
ES2 = ESO(IP,IBAG,ITECH,ISTD)
EH2 = EHO(IP,IBAG,ITECH,ISTD)
* + ( DM(IP,IBAG,ITECH,ISTD)*ODOM(IAGE) )
EM2 = EMO(IP,IBAG,ITECH,ISTD)
* + ( DM(IP,IBAG,ITECH,ISTD)*ODOM(IAGE) )
EN2 = ENO(IP,IBAG,ITECH,ISTD)
* + ( DN(IP,IBAG,ITECH,ISTD)*ODOM(IAGE) )
,For each test type
DO 10 ITEST=1,3
ITEST = 1
ITEST = 2
ITEST = 3
Idle Test
2500/Idle Test
Loaded/Idle Test
,The emissions of vehicles passing the short test are combined
.with the estimated emission levels of vehicles which are repaired.
EIMS = (XSIDRUP, ITECH, ISTD, ITEST) *
* (ES2*(1-RSUP(IP,ITECH,ISTD,ITEST)))) +
* ((1 - XSIDR(IP,ITECH,ISTD,ITEST))*ES2)
EIMH = (XHIDRdP, ITECH, ISTD, ITEST) *
* (EH2*(1-RHIG(IP,ITECH,ISTD,ITEST)))) +
* (d - XHIDRdP, ITECH, ISTD, ITEST) ) *EH2)
EIMM = (XMIDRdP, ITECH, ISTD, ITEST) *
* (EM2*(1-RMAR(IP,ITECH,ISTD,ITEST)))) +
* (d - XMIDRdP, ITECH, ISTD, ITEST) ) *EM2)
.Emission levels by age and by test
.Calculate the base (without I/M) composite emission levels by age
CIMW(IP, IBAG,IAGE,ITECH,ISTD,ITEST) =
* PASS(IAGE,ITECH,ISTD) * EN2
* + EDGE(IAGE,ITECH,ISTD) * EIMM
* + HIGH(IAGE,ITECH,ISTD) * EIMH
* + SUPER(IAGE,ITECH,ISTD) * EIMS
-44-
-------
4058 10 CONTINUE
4059 CC
4060 999 RETURN
4061 END
-45-
-------
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
SUBROUTINE MYRSUB
CC..This section combines the technologies into
CC..model year emission levels.
COMMON /DAT01/ MYR,ISTD,ITECH,IBAG,IP,IAGE,ICUT,ITST
COMMON /DAT06/ FRAC(3,12)
COMMON /DAT09/ ZMIL(2,4,3,2),CWO(2,4,20,3,2),CIMW(2,4,20,3,2,3)
COMMON /DAT10/ EWO(2,4,20,12),EIMW(2,4 , 20, 12,3),EZM(2,4,12)
CC..Loop by MYR, CO standard, technology, age, bag, & pollutant
CC
CC..The ITEST loops only for the I/M composite emission arrays
DO 300 MYR=1,12
ISTD=1
IF(MYR.GE.3) ISTD=2
DO 300 IP=1,2
DO 300 IBAG=1,4
DO 300 ITECH=1,3
Zero mile emission levels by model year
EZM(IP,IBAG,MYR) = EZM(IP,IBAG,MYR)
* + FRAC(ITECH,MYR) * ZMIL(IP,IBAG,ITECH,ISTD)
DO 300 IAGE=1,20
Calculates the emission levels for
CC..January 1st dates from the emission levels by age.
CC..Since model year introduction is on October 1st, this
CC..requires a 75%/25% staggering.
EWO(IP,IBAG,IAGE,MYR) =
* EWO(IP,IBAG,IAGE,MYR)
* + FRAC(ITECH,MYR) * CWO(IP,IBAG,IAGE,ITECH,ISTD)
DO 200 ITEST=1,3
EIMW(IP,IBAG,IAGE,MYR,ITEST) =
* EIMW (IP, IBAG, IAGE, MYR, ITEST)
* + FRAC(ITECH,MYR) * CIMW(IP,IBAG,IAGE,ITECH,ISTD,ITEST)
200 CONTINUE
300 CONTINUE
999 RETURN
END
-46-
-------
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
5028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
SUBROUTINE REGR
, This subroutine uses a weighted regression equation to
.linearize the emission level results for each.model year.
COMMON /DAT01/ MYR,ISTD,ITECH,IBAG,IP,IAGE,ICUT, ITST
COMMON /DAT02/ AMIL(20),ODOM(20),TMILE(20),WGT(20)
COMMON /DAT06/ FRAC(3,12)
COMMON /DAT07/ ESO (2, 4,3,2),EHO(2,4,3,2)
COMMON /DAT08/ DM(2,4,3,2),DN(3, 4, 3, 2)
COMMON /DAT10/ EWO(2,4,20,12),EIMW(2,4,20,12,3),EZM(2,4,12)
COMMON /DAT12/ ZML(3,4,12),ZML1(3,4,12),ZML2(3,4,12)
COMMON /DAT14/ DET(3,4,12),DET1(3,4,12),DET2(3,4,12)
COMMON /DAT20/ EMO(2,4,3,2),ENO(3,4,3,2)
DO 40 MYR=1,12
DO 40 IBAG=1,4
DO 40 IP=1,2
SUMX
SUMY
SUMXY
SUMXX
N = 5
0.0
0.0
0.0
0.0
DO 10 IAGE=1,N
IF(IAGE.EQ.l) EM
IF(IAGE.GT.l) EM
IF(IAGE.EQ.l) XM
IF(IAGE.GT.l) XM
SUMX = SUMX +
SUMY = SUMY +
SUMXY = SUMXY -I-
SUMXX = SUMXX +
10 CONTINUE
= EZM (IP, IBAG, MYR)
= EWO (IP, IBAG, IAGE-1, MYR)
= 0.0
= ODOM (IAGE-1)
XM
EM
(XM*EM)
(XM**2)
SUM1 = N * SUMXY - SUMX * SUMY
SUM2 = N * SUMXX - SUMX**2
Dl = SUM1 / SUM2
Zl = (SUMY/N) - Dl * (SUMX/N)
.Store the regression results
ZML1 (IP, IBAG, MYR) = Zl
DET1 (IP, IBAG, MYR) = Dl
ZML2 (IP, IBAG, MYR) = ZML1 (IP, IBAG, MYR) + DET1 (IP, IBAG, MYR) *5 . 0
IF(ZML1 (IP, IBAG, MYR) .GE.0.0) GO TO 30
.If the emission level at zero miles is less than zero,
.then the regression is altered to intercept at zero.
ZMLKIP, IBAG, MYR) =0.0
-47-
-------
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
CC
cc
CC
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
c
cc
cc
cc
cc
cc
cc
DET1 (IP, IBAG,MYR) = SUMXY / SUMXX
ZML2(IP,IBAG,MYR) = ZML1 (IP, IBAG, MYR) + DEI
30 SUMX =0.0
SUMY =0.0
SUMXY =0.0
SUMXX =0.0
M = 16
DO 20 IAGE=6,21
IF(IAGE.EQ.l) EM = EZM (IP, IBAG, MYR)
IF(IAGE.GT.l) EM = EWO (IP, IBAG, IAGE-1, MYR)
IF(IAGE.EQ.l) XM = 0.0
IF(IAGE.GT.l) XM = ODOM ( IAGE-1)
SUMX = SUMX + XM
SUMY = SUMY + EM
SUMXY = SUMXY + (XM*EM)
SUMXX = SUMXX + (XM**2)
20 CONTINUE
SUM1 = M * SUMXY - SUMX * SUMY
SUM2 = M * SUMXX - SUMX** 2
Dl = SUM1 / SUM2
Zl = (SUMY/M) - Dl * (SUMX/M)
..Store the regression results
DET2 (IP, IBAG, MYR) = Dl
..Single Linear Regression
SUMX =0.0
SUMY =0.0
SUMXY =0.0
SUMXX =0.0
SUMW =0.0
DO 60 IAGE=1,20
IF(IAGE.EQ.l) EM = EZM (IP, IBAG, MYR)
IF(IAGE.GT.l) EM = EWO (IP, IBAG, IAGE-1, MYR)
IFdAGE.EQ. 1) XM = 0.0
IF(IAGE.GT.l) XM = ODOM (IAGE-1)
SUMX = SUMX -i- ( WGT(IAGE) * XM )
SUMY = SUMY + ( WGT(IAGE) * EM )
SUMXY = SUMXY + ( WGT(IAGE) * (XM*EM) )
SUMXX = SUMXX + ( WGT(IAGE) * (XM**2) )
60 CONTINUE
SUM1 = SUMXY - SUMX * SUMY
-48-
-------
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
CC
cc
CC
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
SUM2 = SUMXX - SUMX**2
Dl = SUM1 / SUM2
Zl = SUMY - Dl * SUMX
CC..Store the regression results
ZML(IP,IBAG,MYR) = Zl
DET(IP,IBAG,MYR) = Dl
IF(ZML(IP,IBAG,MYR).GE.0.0) GO TO 40
CC..If the emission level at zero miles is less than zero,
CC..then the regression is altered to intercept at zero.
ZML(IP,IBAG,MYR) =0.0
DET(IP,IBAG,MYR) = SUMXY / SUMXX
40 CONTINUE
CC..Since the NOx emissions are not combined from emission level
CC..groups, the NOx emission factors can be calculated directly
CC..from the regressions.
IP=3
DO 50 MYR=1,12
ISTD=1
IF(MYR.GE.3) ISTD=2
DO 50 IBAG=1,4
DO 50 ITECH=1,3
ZML(IP,IBAG,MYR) = ZML (IP,IBAG,MYR) +
* ENO(IP, IBAG,ITECH,ISTD)*FRAC(ITECH,MYR)
DET(IP,IBAG,MYR) = DET(IP,IBAG,MYR) +
* DN(IP,IBAG,ITECH,ISTD)*FRAC(ITECH,MYR)
ZML1(IP,IBAG,MYR)=ZML(IP,IBAG, MYR)
DET1(IP,IBAG,MYR)=DET(IP,IBAG,MYR)
DET2(IP,IBAG,MYR)=DET(IP,IBAG,MYR)
50 CONTINUE
CALL BAGF
999 RETURN
END
-49-
-------
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
703.4
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
CC
CC.
CC
CC.
CC
CC
CC
CC
CC
CC
CC.
CC
CC
CC
CC
CC.
CC
CC
CC.
CC
CC
CC
CC
SUBROUTINE BAGF
.This routine calculates the bag fractions for hot/cold starts
.Last. Updated : November 15, 1988
COMMON /DAT01/ MYR, ISTD, ITECH, I BAG, IP, IAGE, ICUT, ITST
COMMON /DAT12/ ZML(3, 4, 12) , ZML1 (3, 4, 12) , ZML2 (3, 4, 12)
COMMON /DAT13/ BFZML1 (3, 4, 12) , BFDET1 (3, 4, 12)
COMMON /DAT14/ DET (3, 4, 12) , DET1 (3, 4, 12) , DET2 (3, 4, 12)
COMMON /DAT21/ BFDET2 (3, 4 , 12) , BFZML2 (3, 4, 12)
DIMENSION BFRAC(4)
DATA BFRAC / 1.000, 0.206, 0.521, 0.273 /
DO 20 IP=1,3
DO 20 MYR=1, 12
Z2 = 0.0
Z3 = 0.0
D2 = 0.0
D3 = 0.0
.Sum up the bag regression coeffs weighted by the FTP bag fractions
DO 10 IBAG=2, 4
Z2 = Z2 + ZML1 (IP, IBAG,MYR) * BFRAC (IBAG)
Z3 = Z3 + ZML2 (IP, IBAG, MYR) * BFRAC (IBAG)
D2 = D2 + DET1 (IP, IBAG, MYR) * BFRAC (IBAG)
• D3 = D3 + DET2 (IP, IBAG, MYR) * BFRAC (IBAG)
10 CONTINUE
.Set the combined FTP bag fraction to 1.00
BFZML1 (IP, 1,MYR) = Z2 / Z2
BFZML2 (IP, 1,MYR) = Z3 / Z2
BFDET1 (IP, 1,MYR) = D2 / Z2
BFDET2 (IP, 1,MYR) = D3 / Z2
.Divide each bag regression coeff by the weighted sum
DO 20 IBAG=2, 4
BFZML1 (IP, IBAG, MYR) = ZML1 (IP, IBAG, MYR) / Z2
BFZML2 (IP, IBAG, MYR) = ZML2 (IP, IBAG, MYR) / Z2
BFDET1 (IP, IBAG, MYR) = DET1 (IP, IBAG, MYR) / Z2
BFDET2 (IP, IBAG, MYR) = DET2 (IP, IBAG, MYR) / Z2
20 CONTINUE
RETURN
END
-50-
-------
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
CC
cc.
CC.
cc.
cc
cc
cc
cc
cc
cc.
cc.
cc
cc
' cc
cc
cc
cc.
cc.
cc
cc
cc
cc.
cc
cc
cc.
cc
cc
SUBROUTINE JAN1
.This subroutine calculates the average emissions of each
.model year on January first. It creates the I/M credits
.and passes them to OUTPUT.
COMMON /DAT02/ AMIL (20) , ODOM (20) , TMILE (20) , WGT (20)
COMMON /DAT10/ EWO (2, 4, 20, 12) , EIMW (2, 4, 20, 12, 3) , EZM (2, 4, 12)
COMMON /DAT11/ CREDIT (2, 20, 12, 3, 4) .
COMMON /DAT12/ ZML (3, 4, 12) , ZML1 (3, 4, 12) , ZML2 (3, 4, 12)
COMMON /DAT14/ DET (3, 4, 12) , DET1 (3, 4, 12) , DET2 (3, 4, 12)
DIMENSION ANSWNO(2,20,12) , ANSWIM (2, 20, 12, 3, 3)
DIMENSION EPRED(2,4,20, 12,3) ,PRED(2, 4,20, 12,3)
DIMENSION SLOPE (2, 12,21) , ZERO (2, 12,21)
IBAG = 1
DO 100 MYR = 1, 12
DO 100 IP = 1,2
.The deteriorations before and after the "KINK" are transferred
.to the array SLOPE for each vehicle age.
DO 95 I = 1,20
IF(I.LE.4) SLOPE (IP, MYR, I) = DET1 (IP, IBAG, MYR)
IF(I.GE.S) SLOPE (IP, MYR, I) = DET2 (IP, IBAG, MYR)
. IF(I.LE.4) ZERO (IP, MYR, I) = ZML1 (IP, IBAG, MYR)
IF(I.GE.S) ZERO (IP, MYR, I) = ZML2 (IP, IBAG, MYR) -
* DET2 (IP, IBAG, MYR) *5.0
95 CONTINUE
.Computes the NON-I/M emission level by age, by pollutant,
.by bag, and by myr.
DO 100 IAGE = 1,19
IF(IAGE .GT. 1) GOTO 33
.Vehicle age is one.
ANSWNO(IP, IAGE, MYR) =
*. 75* (ZERO (IP, MYR, IAGE) + SLOPE (IP, MYR, IAGE) *. 625*ODOM (IAGE) ) +
*.25* (ZERO (IP, MYR, IAGE+1) + SLOPE (IP, MYR, IAGE+1) *
* (.125* (ODOM (IAGE+1 ) -ODOM (IAGE) ) +ODOM ( IAGE) ) )
GOTO 34
.Vehicle age is greater than one.
33 ANSWNO(IP, IAGE, MYR) =
*. 75* (ZERO (IP, MYR, IAGE) + SLOPE (IP, MYR, IAGE) *
* (.625* (ODOM (IAGE) -ODOM (IAGE-1) ) +ODOM (IAGE-1) ) ) +
*. 25* (ZERO (IP, MYR, IAGE+1) + SLOPE (IP, MYR, IAGE+1) *
* (.125* (ODOM (IAGE+1 ) -ODOM (IAGE) ) +ODOM ( IAGE) ) )
-51-
-------
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
.Compute the I/M emission level by age, by pollutant,
.by bag, by myr and by test for IAGE = 1. The predicted emission
.level is from the regression equation and the actual model
.emission level points.
34 DO 100 ITEST=1,3
EPREDdP, IBAG, IAGE, MYR, ITEST) =
* 1 - ((EWO(IP,IBAG,IAGE,MYR) - EIMW(IP,IBAG,IAGE,MYR,ITEST)) /
* EWO(IP,IBAG,IAGE,MYR))
PRED(IP,IBAG,IAGE,MYR,ITEST) =
* (ZERO(IP,MYR,IAGE) + SLOPE(IP,MYR,IAGE)*ODOM(IAGE)) *
* EPREDdP, IBAG, IAGE, MYR, ITEST)
.Determine I/M credits for each inspection frequency.
ITYP = 1 : Annual
2 : Biennial 1 - 3 - 5 - etc
3 : Biennial 2 - 4 - 6 - etc
DO 110 ITYP = 1,3
IF(ITYP.GE.2) GOTO 60
.Annual I/M Credits
IF(IAGE .GT. 1) GOTO 50
ANSWIM (IP, IAGE, MYR, ITEST, ITYP) =
* (.75* (.62 5* SLOPE (IP, MYR, IAGE) *ODOM(IAGE) + ZERO (IP, MYR, IAGE) ))
* + .25*(PRED(IP,IBAG,IAGE,MYR,ITEST) + SLOPE(IP,MYR,IAGE+1)*
* (.125*(ODOM(IAGE+1)-ODOM(IAGE))) )
GOTO 60
50 ANSWIM(IP,IAGE,MYR,ITEST,ITYP) =
*.75*(PRED(IP,IBAG,IAGE-1,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE) * (.625*(ODOM(IAGE)-ODOM(IAGE-1))) ) +
*.25*(PRED(IP,IBAG,IAGE,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE+1) * (.125*(ODOM(IAGE+1)-ODOM(IAGE))) )
GOTO 90
.Biennial I/M Credits
IMODE = 1 : Odd year
2 : Even year
60 IMODE = MOD(IAGE,2)
.Biennial 1 - 3 - 5 - etc 1st Year Exception
same as no I/M first year
IF(ITYP .EQ. 2 .AND. IAGE .EQ. 1)
* ANSWIM (IP, IAGE, MYR, ITEST, ITYP) =
* (.75* (.625*SLOPE(IP,MYR, IAGE) *ODOM(IAGE) + ZERO (IP, MYR, IAGE) ))
* + .25*(PRED(IP,IBAG,IAGE,MYR,ITEST) + SLOPE(IP,MYR,IAGE+1)*
* (.125*(ODOM(IAGE+1)-ODOM(IAGE))) )
-52-
-------
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
CC
CC.
CC.
CC
CC
CC.
CC
CC
CC
CC.
CC
CC.
CC
CC
CC
CC.
CC.
CC
CC
CC.
CC
CC
1
CC
CC.
CC
.Biennial 2 - 4 - 6 - etc 1st Year Exception
same .as no I/M first year
IF(ITYP .EQ. 3 .AND. IAGE .EQ. 1)
* ANSWIM(IP,IAGE,MYR,ITEST,ITYP) =
* .75*(ZERO(IP,MYR,IAGE) + SLOPE(IP,MYR,IAGE)*.625*ODOM(IAGE))+
* .25*(ZERO(IP,MYR,IAGE) + SLOPE(IP,MYR,IAGE+1)*
* (.125*(ODOM(IAGE+1)-ODOM(IAGE))+ODOM(IAGE)) )
.Biennial 2 - 4 - 6 - etc 2nd Year Exception
IF(ITYP .EQ. 3 .AND. IAGE .EQ. 2)
* ANSWIM(IP,IAGE,MYR,ITEST,ITYP) =
* .75*(ZERO(IP,MYR,IAGE) +
* SLOPE(IP,MYR,IAGE)*(ODOM(IAGE-1)) +
* SLOPE(IP,MYR,IAGE)*(.625*(ODOM(IAGE)-ODOM(IAGE-1)))) +
* .25*(PRED(IP,IBAG,IAGE,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE+1)*.125*(ODOM(IAGE+1)-ODOM(IAGE)))
IF(IAGE.EQ.l .OR. (ITYP.EQ.3 .AND. IAGE.EQ.2)) GOTO 90
.The Principle Biennial Cases 1-3-5-etc and 2-4-6-etc
.An Even Year for the 1-3-5 or An Odd Year for the 2-4-6
.There is no I/M inspection that year
IF((IMODE.EQ.l .AND. ITYP.EQ.3) .OR. (IMODE.EQ.0.AND.ITYP.EQ.2))
* ANSWIM(IP,IAGE,MYR,ITEST,ITYP) =
* .75*(PRED(IP,IBAG,IAGE-1,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE)*(.625*(ODOM(IAGE)-ODOM(IAGE-1)))) +
* .25*(PRED(IP,IBAG,IAGE-1,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE)*(ODOM(IAGE)-ODOM(IAGE-1)) +
* SLOPE(IP,.MYR,IAGE+1)*.125*(ODOM(IAGE+1)-ODOM{IAGE)))
.An Odd Year for the 1-3-5 or An Even Year for the 2-4-6
There is an I/M inspection that year
IF((IMODE.EQ.0 .AND. ITYP.EQ.3) .OR. (IMODE.EQ.1.AND.ITYP.EQ.2))
* ANSWIM(IP,IAGE,MYR,ITEST,ITYP) =
* .75*(PRED(IP,IBAG,IAGE-2,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE-1)*(ODOM(IAGE-1)-ODOM(IAGE-2)) +
* SLOPE(IP,MYR,IAGE)*(.625*(ODOM(IAGE)-ODOM(IAGE-1)))) +
* .25*(PRED(IP,IBAG,IAGE,MYR,ITEST) +
* SLOPE(IP,MYR,IAGE+1)*(.125*(ODOM(IAGE+1)-ODOM(IAGE))))
.Combined 1-3-5 and 2-4-6 biennial cases
90 CREDIT(IP,IAGE,MYR,ITEST,ITYP) =
* (ANSWNOdP, IAGE, MYR) -ANSWIM (IP, IAGE, MYR, ITEST, ITYP) )
* / (ANSWNOdP, IAGE, MYR) )
10 CONTINUE
.Store resulting I/M credits
CREDIT(IP,IAGE,MYR,ITEST, 4) =
* (CREDIT(IP,IAGE,MYR,ITEST,2) + CREDIT(IP,IAGE,MYR,ITEST,3))/2
-53-
-------
8174 CC
8175 100 CONTINUE
8176 CC
8177 RETURN
8178 END
-54-
-------
9000
9001
9002
9003
9004
9005
9006
9007
9008
9009
9010
9011
9012
9013
9014
9015
9016
9017
9018
9019
9020
9021
9022
9023
9024
9025
9026
9027
9028
9029
9030
9031
9032
9033
9034
9035
9036
9037
9038
9039
9040
9041
9042
9043
9044
9045
9046
9047
9048
9049
9050
9051
9052
9053
9054
9055
9056
9057
CC
cc
CC
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
SUBROUTINE OUTPUT
.Outputs results for emission factors, bag fractions and
.I/M credits.
COMMON /DAT11/ CREDIT(2,20, 12, 3, 4)
COMMON /DAT12/ ZML(3,4,12),ZML1(3,4,12),ZML2(3,4,12)
COMMON /DAT13/ BFZML1(3,4,12),BFDET1(3,4,12)
COMMON /DAT14/ DET(3,4,12),DET1(3,4,12),DET2(3,4,12)
COMMON /DAT21/ BFDET2(3,4,12),BFZML2(3,4,12)
',' NOX'/
INTEGER ITEST,ICUTS,STD,IP,IBY,IBAG
CHARACTER*4 LABI (3)/' HC',' CO
CHARACTER*4 LAB2(5)/'FTP ',
* 'BAG1',
* 'BAG2',
* 'BAG3',
* 'BAGI'/
NP = 3
Nl = 1
N3 = 3
..Write out Annual I/M credits on Device #7
WRITE(7,102) N3
DO 10 ITEST=1,3
DO 10 MYR=1,12
NYR=1980+MYR
DO 10 IP=1,2
WRITE(7,200) (CREDIT(IP,IAGE,MYR,ITEST, 1),IAGE=1,19),
* NYR,LAB1(IP)
10 CONTINUE
..Write out Biennial I/M Credits on Device #1
WRITE(1,103) N3
DO 130 ITEST=1,3
DO 130 MYR=1,12
NYR=1980+MYR
DO 130 IP=1,2
WRITE(1,200) (CREDIT(IP,IAGE,MYR,ITEST, 4) , IAGE=1, 19),
* NYR,LABI(IP)
130 CONTINUE
..Write out MOBILE4 Emission Facors on Device #8
WRITE(8,100) Nl
WRITE(8,600)
DO 20 IP=1,NP
WRITE(8,500)
DO 20 MYR=1,12
NYR=1980+MYR
IBAG=1
T50 = ZML1(IP,IBAG,MYR) + 5.0*DET1(IP,IBAG,MYR)
T100 = T50 + 5.0*DET2(IP,IBAG,MYR)
WRITE(8,300) NYR,LAB2(IBAG),LAB1(IP) ,
* ZML1(IP,IBAG,MYR),DET1(IP,IBAG,MYR),DET2(IP,IBAG,MYR),
-55-
-------
9058 * T50,T100,ZML(IP,IBAG,MYR),DET(IP,IBAG,MYR)
9059 20 CONTINUE
9060 CC
9061 CC..Write out bag fractions on Device #9
9062 CC
9063 WRITE (9-, 101) Nl
9064 DO 30 IP=1,3
9065 WRITE(9,500)
9066 DO 30 MYR=1,12
9067 NYR=1980+MYR
9068 WRITE(9,400) NYR,LABI(IP),
9069 *(BFZML1(IP,IBAG,MYR),BFDET1(IP,IBAG,MYR),BFZML2(IP,IBAG,MYR),
9070 * BFDET2(IP,IBAG,MYR),IBAG=2,4),
9071 * BFZML1(IP,1,MYR),BFDET1(IP,1,MYR),BFZML2(IP,1,MYR),
9072 * BFDET2(IP,1,MYR)
9073 30 CONTINUE
9074 CC
9075 100 FORMAT(II,/,' **',/,
9076 *' ** MOBILE4 LDGV Emission Factors',
9077 *' (February 1989) ',
9078 */,' **')
9079 101 FORMAT(II,/,/,
9080 *' ** MOBILE4 LDGV Bag Fractions (February 1989)**',/,/,
9081 *23X,'Bag l',20X,'Bag 2',25X,'Bag 3',25X,'FTP',/,
9082 *9X,4(' '),/,
9083 *9X,4(' ZML1 DET1 ZML2 DET2'),/,
9084 *9X,4(' '))
9085 102 FORMAT(II,/,' **',/,
9086 *' ** MOBILE4 Annual I/M Credits (February 1989)',
9087 */,' **')
9088 103 FORMAT(II,/,' **',/,
9089 *' ** MOBILE4 Biennial I/M Credits (February 1989)',
9090 */,' **')
9091 200 FORMAT(19F4.3,5X,14,A4)
9092 600 FORMAT(29X,' ZML ',3X,' DET1 ',18X,' DET2 ',18X,
9093 * ' @ 50k',' @100k',3X,' ZML ',3X,' DET ')
9094 300 FORMAT(
9095 * IX,14,' EF Equation : ',2A4,'=',
9096 * F6.3,' + ',F6.3,' * Mi/lOk(<50K) ' , 3X,
9097 *F6.3,' * Mi/10k(>50K)',3X,2F10.3,2(3X,F6.3))
9098 400 FORMAT(IX,14,A4,16F7.4)
9099 500 FORMAT ('-' )
9100 CC
9101 RETURN
9102 END
-56-
-------
10000 BLOCK DATA BD01
10001 CC
10002 CC..This block data is used to initialize data arrays
10003 CC
10004 COMMON /DAT10/ EWO(2,4,20,12),EIMW(2,4,20,12,3),EZM(2,4,12)
10005 COMMON /DAT12/ ZML (3, 4, 12) , ZML1 (3, 4, 12) , ZML2 (3, 4, 12)
10006 COMMON /DAT14/ DET(3,4,12),DET1(3,4,12),DET2(3,4,12)
10007 CC
10008 DATA EWO / 1920*0.0 /
10009 DATA EIMW / 5760*0.0 /
10010 DATA EZM / 96*0.0 /
10011 CC
10012 DATA ZML / 144*0.0 /
10013 DATA ZML1 / 144*0.0 /
10014 DATA ZML2 / 144*0.0 /
10015 CC
10016 DATA DET / 144*0.0 /
10017 DATA DET1 / 144*0.0 /
10018 DATA DET2./ 144*0.0 /
10019 CC
10020 END
-57-
-------
11000
11001
11002
11003
11004
11005
11006
11007
11008
11009
11010
11011
11012
11013
11014
11015
11016
11017
11018
11019
11020
1102.1
11022
11023
11024
11025
11026
11027
11028
11029
11030
11031
11032
11033
11034
11035
11036
11037
11038
11039
11040
11041
11042
11043
11044
11045
11046
11047
11048
11049
11050
11051
11052
11053
11054
11055
11056
11057
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
BLOCK DATA EDO2
.Emission Level Data Block
COMMON /DAT05/ SNO(3,2),SMO(3,2)
COMMON /DAT07/ ESO(2,4,3,2),EHO(2,4,3,2)
COMMON /DAT19/ GM(3,2),GH(3,2),GS(3,2),BEND(3,2)
Change in the rate of increase in the number of HIGH emitters
BEND(ITECH,ISTD)
DATA BEND / 6*3.1031 /
Growth in the number of SUPERS per 10,000 miles
GS(ITECH,ISTD)
DATA GS / 6*.002180 /
Growth in the number of HIGHS per 10,000 miles
GH(ITECH,ISTD)
DATA GH /
.Number of FTP failures at zero miles
SMO(ITECH,ISTD)
CARB
.016257,
.023528,
FI
.022202,
.015340,
OPLP
.011799,
.008304 /
DATA SMO /
.20788,
.088884,
.10564,
.35977,
.35484,
.70248 /
.Growth in the number of FTP failures per 10,000 miles
, (Used to calculate the number of Marginal Emitters)
GM(ITECH,ISTD)
DATA GM /
0.095371,
0.094791,
0.078771,
0.067288,
0.073221,
0.028347 /
.Average emissions of SUPERS (from 17 EF & IM vehicles)
ESO (IP,IBAG,ITECH,ISTD)
DATA ESO /
.1981,1982 model year vehicles
1 14.272, 171.732, 17.118,169.759,15.239,184.853,10.256,148.371,
2 14.272, 171.732, 17.118,169.759,15.239,184.853,10.256,148.371,
3 0.00, 0.00, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000,
.1983 and newer model year vehicles
1 14.272, 171.732, 17.118,169.759,15.239,184.853,10.256,148.371,
2 14.272, 171.732, 17.118,169.759,15.239,184.853,10.256,148.371,
3 0.00, 0.00, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000 /
.Emission Levels of HIGH Emitters at zero miles
EHO(IP,IBAG,ITECH,ISTD)
DATA EHO/
.1981,1982 model year vehicles
* 2.1984, 33.659, 4.207,47.426,1.797,32.582,1.445,25.324,
-58-
-------
11058 * 0.8610, 11.901, 1.883,30.409,0.568,06.391,0.601,06.749,
11059 * 2.1793, 31.933, 3.604,47.209,1.686,27.176,2.030,28.150,
11060 CC..1983 and newer vehicles
11061 * 0.9543, 13.197, 2.769,32.539, .172, 5.854, .582,13.530,
11062 * 1.2596, 13.789, 2.226,29.151, .986, 9.183, .998,10.604,
11063 * 2.1224, 32.014, 3.961,54.979,1.532,24.740,1.839,26.080 /
11064 CC
11065 END
-59-
-------
12000
12001
12002
12003
12004
12005
12006
12007
12008
12009
12010
12011
12012
12013
12014
12015
12016
12017
12018
12019
12020
12021
12022
12023
12024
12025
12026
12027
12028
12029
12030
12031
12032
12033
12034
12035
12036
12037
12038
12039
12040
12041
12042
12043
12044
12045
12046
12047
12048
12049
12050
1205-1
12052
12053
12054
12055
12056
12057
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
BLOCK DATA EDO3
. I/M effects block 'data (IDR & Repair Effects)
COMMON /DAT16/ XSIDR(2,3,2,3),XHIDR(2,3,2,3)
COMMON /DAT17/ RSUP(2,3,2,3),RHIG(2,3, 2, 3)
COMMON /DAT22/ RMAR(2, 3, 2, 3)
COMMON /DAT24/ XMIDR(2, 3, 2, 3)
.Emission level after repairs expressed as a fraction of
,the emission level before repairs.
RSUP(IP,ITECH,ISTD,ITEST)
DATA RSUP/
.Idle test emission effect from repairs for SUPERS
1 .851, .919, .699, .755, .000, .000,
2 .851, .919, .699, .755, .000, .000,
,2500/Idle test emission effect of repairs for SUPERS
1 .834, .892, .908, .974, .000, .000,
2 .834, .892, .908, .974, .000, .000,
.Loaded/Idle test emission effect of repairs for SUPERS
1 .834, .892, .908, .974, .000, .000,
2 .834, .892, .908, .974, .000, .0007
RHIG(IP,ITECH,ISTD,ITEST)
DATA RHIG/
.Idle test emission effect from repairs for HIGHS
1 .514, .568, .603, .683, .561, .665,
2 .514, .568, .603, .683, .561, .665,
.2500/Idle test emission effect of repairs for HIGHS
1 .583, .639, .649, .749, .596, .725,
2 .583, .639, .649, .749, .596, .725, .
.Loaded/Idle test emission effect of repairs for HIGHS
1 .583, .639, .649, .749, .596, .725,
2 .583, .639, .649, .749, .596, .725 /
RMAR(IP,ITECH,ISTD,ITEST)
DATA RMAR/
,Idle test emission effect from repairs for MARGINALS
1 .209, .247, .268, .320, .208, .372,
2 .209, .247, .268, .320, .208, .372,
.2500/Idle test emission effect of repairs for MARGINALS
1 .206, .232, .268, .320, .145, .301,
2 .206, .232, .268, .320, .145, .301,
.Loaded/Idle test emission effect of repairs for MARGINALS
1 .206, .232, .268, .320, .145, .301,
2 .206, .232, .268, .320, .145, .301 /
.The fraction of excess emissions identified by the short
.test for each emission level group.
XSIDR(IP,ITECH,ISTD,ITEST)
DATA XSIDR/
.Idle test identification rate for SUPERS
-60-
-------
12058
12059
12060
12061
12062
12063
12064
12065
12066
12067
12068
12069
12070
12071
12072
12073
12074
12075
12076
12077
12078
12079
12080
12081
12082
12083
12084
12085
12086
12087
12088
12089
12090
12091
12092
12093
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
• cc
CC
CC
1 .5526, .7172,.5526,.7172,.0, .0,
2 .5526,.7172,.5526,.7172, .0, .0,
2500/Idle test identification rate for SUPERS
1 - .5526,.7172,.5526,.7172, .0, .0,
2 .5526,.7172,.5526,.7172,.0, .0,
Loaded/Idle test identification rate for SUPERS
1 .5863,.8490,.5863,.8490,.0, .0,
2 .5863,.8490,.5863,.8490,.0, .07
XHIDR(IP,ITECH,ISTD,ITEST)
DATA XHIDR/
.Idle test identification fraction for HIGHS
1 .3574, .4124, .1557, .2374, .6061, .6114,
2 .3574, .4124, .1557,.2374, .6061, .6114,
2500/Idle test identification fraction for HIGHS
1 .4290,.4990,.1893,.2580,.7157,.7747,
2 .4290,.4990,.1893,.2580,.7157,.7747,
Loaded/Idle test identification fraction for HIGHS
1 .5399, .6376, .1893,.2580, .6622, .7582,
2 .5399, .6376, .1893, .2580,.6622, .7582 /
XMIDR(IP,ITECH,ISTD, ITEST)
DATA XMIDR/
Idle test identification fraction for MARGINALS
1 .0334, .0151,.0746,.0833,.0380,.0486,
2 .0334,.0151,.0746,.0833,.0380, .0486,
, 2500/Idle test identification fraction for MARGINALS
1. .0334, .0151, .0830, .0860, .0520, .0690,
2 .0334, .0151, .0830, .0860,.0520, .0690,
Loaded/Idle test identification fraction for MARGINALS
1 .0571,.0536,.1129,.1254,.0455,.0925,
2 .0571,.0536,.1129,.1254,.0455,.0925'/
END
-61-
-------
13000
13001
13002
13003
13004
13005
13006
13007
13008
13009
13010 '
13011
13012
13013
13014
13015
13016
13017
13018
13019
13020
13021
13022
13023
13024
13025
13026
13027
13028
13029
13030
13031
13032
13033
13034
13035
13036
13037
13038
13039
13040
13041
13042
13043
13044
13045
13046
13047
13048
13049
13050
13051
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
CC
BLOCK DATA EDO4
.Fleet Description Block
COMMON /DAT02/ AMIL(20),ODOM(20),TMILE(20),WGT(20)
COMMON /DAT06/ FRAC(3,12)
.Technology Sales Fractions Projections
FRAC(ITECH,MYR)
DATA FRAC /
CARS FI OPLP
.1981 Model Year
* .635, .084, .281,
.1982 Model Year
* .499, .171, .330,
,1983 Model Year
* .456, .303, .241,
.1984 Model Year
* .460, .485, .055,
.1985 Model Year
* .393, .545, .062,
.1986 Model Year
* .260, .670, .070,
.1987 Model Year
* .239, .747, .014,
.1988 Model Year
* .189 , .811, .000,
.1989 Model Year
* .163, .837, .000,
.1990 Model Year
* .137, .863, .000,
.1991 Model Year
* .084, .916, .000,
.1992 and Newer Model Years
* .043, .957, .000 /
.Fleet January 1st VMT weighting factors (MOBILE4)
DATA WGT / 0.030,
0.078,
0.120,
0.068,
0.111,
0.060,
0.099,
0.054,
0.043, 0.038, 0.033, 0.028,
0.088,
0.048,
0.024,
* 0.020, 0.017, 0.013, 0.010, 0.019/
.Fleet average odometer mileage by vehicle age (MOBILE4)
DATA ODOM/ 1.3118, 2.6058, 3.8298, 4.9876, 6.0829,
* 7.1190, 8.0991, 9.0262, 9.9031,10.7326,
* 11.5172,12.2594,12.9615,13.6257,14.2540,
* ' 14.8483,15.4104,15.9421,16.4451, 16.92097
END
-62-
-------
14000
14001
14002
14003
14004
14005
14006
14007
14008
14009
14010
14011
14012
14013
14014
14015
14016
14017
14018
14019
14020
14021
14022
14023
14024
14025
14026
14027
14028
14029
14030
14031
14032
14033
14034
14035
14036
14037
14038
14039
14040
14041
14042
14043
14044
14045
14046
14047
14048
14049
14050
14051
14052
14053
14054
14055
14056
14057
CC
cc
CC
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
cc
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• cc
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BLOCK DATA EDO5
.Emission Level Data Block
COMMON /DAT08/ DM (2, 4, 3, 2) , DN (3, 4, 3, 2)
COMMON /DAT20/ EMO(2,4,3,2),ENO(3,4,3,2)
.Emission level of MARGINALS at zero mileage
EMO(IP,IBAG,ITECH,ISTD)
DATA EMO/
,1981,1982 model year vehicles
1 0.5333, 5.358, 1.321,15.34,.276,2.16,.426,3.89,
2 0.4277, 5.333, 1.095,14.89,.222,2.66,.282, 2.08,
3 0.4684, 6.818, . 822,12.69,.310,3.35, .496,6.91,
,1983 and newer model year vehicles
10.3482, 4.602, .889,15.81, . 184,1.17, .245,3.48,
2 0.3668, 4.360, .939, 9.76,.159,2.28,.293,3.97,
30.3703, 4.881, . 787,12.10, .200,1.32, .379,5.16 /
.Emission deterioration MARGINALS per 10,000 miles
DM(IP,IBAG,ITECH, ISTD)
DATA DM/
1981,1982 model year
1 0.00871, 0.3490,
2 0.01129, 0.1731, .
3 0.01372, 0.1211, .
1983 and newer model
1 0.02071, 0.1089,
2 0.00077, 0.0853, .
3 0.02295, 0.1080,
vehicles
015, .812,.008,
000, .000,.012,
063,1.261,.002,
year vehicles
056, .056,.006,
000, .128,.007,
005, .000,.027,
223,
153,
000,
000,
154,
233,
.005,
.025,
.000,
.024,
.000,
.031,
.238,
.574,
.000,
.118,
.000,
.336 /
.Emission level of vehicles passing FTP at zero mileage
END(IP,IBAG,ITECH,ISTD)
DATA ENO /
1981,1982 model year vehicles
1 0.2437, 2.686, 0.6781, .66,8.45,1.2,
10, .64,.49,.20,2.19,.64,
20.2288, 2.368, 0.4995, . 70,5.74,.88, .09,1.38, .39, .14,1.69, .43,
3 0.2600, 2.465, 0.6333, . 57,7.19, .97, .15, .68,.50,.24,2 . 22, . 64,
,1983 and newer model year vehicles
10.1924, 1.619, 0.7030, .49,5.34,1.1, .09, .22, .52,.15,1. 45, . 76,
2 0.2317, 2.176, 0.6322, .64,5.88,1.0, .09, .84, .48, .17,1.92, .63,
3 0.2395, 2.385, 0.4893, . 48,8.19,.60,.17, .24, .44, .25,2.12, .49 /
.Emission deterioration of vehicles passing FTP per 10,000 miles
DN(IP,IBAG,ITECH,ISTD)
DATA DN /
,1981,1982 model year vehicles
1 .01223, .1557, .0689, .019,.29,.06, .Oil, .14, . 07,.Oil, . 09, . 09,
2 .01106, .2391, .1358, . 020,.68, .14,.009,.12,.12, .009, .14, .16,
3 .01237, .1256, .0410, .047, .56,.03,.004,.04, .04, .002, . 00, . 05,
,1983 and newer model year vehicles
1 .01615, .1089, .0340, . 033,.28, .03, .Oil, .05, .03,.013, . 10, . 04,
-------
14058 2 .00387, .0781, .0338, .020,.05,.04,.002,.10,.02,.000,.05,.05,
14°59 3 .01237, .1256, .0559, .023,.00,.07,.000,.23,.05,.000,.00,.05 /
14060 CC
14061 END
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