-------
Table 6-7
COST SUMMARY OF I/M OPTIONS
(1978 Dollars)
OPTION 1 OPTION 2 OPTION 3
1. First-Year Capital Costs
State's Share 31,644,400 5,944,300 6,001,300
Contractor's Share 0 25,700,100 29,759,400
2. Annualized Program Costs 34,595,200 38,443,400 50,044,568
State's Share 34,595,200 8,214,000 10,099,525
Contractor's Share 0 30,229,400 39,945,043
3. Consumer Fee (LDV) 5.66 6.29 8.28
State's Share 5.66 1.34 1.67
Contractor's Share 0 4.95 6.61
4. Consumer Fee (HDG) 16.47 18.30 21.30
State's Share 16.47 3.91 4.30
Contractor's Share 0 14.39 17.00
- 6-9
-------
initial capital costs to the state. Comparing Options 1 and 2, contractor's
costs (Option 2) are slightly higher than those for the state option
(Option 1).
The inspection fee required under each option is also presented in
Table 6-7. As expected, the fee is lowest for Option 1 and highest for Option 3,
Fee for testing HDGs is approximately two times more than that for testing
LDVs.
6.3 FUEL SAVINGS BENEFITS
The fuel savings benefits are based upon data set forth in Section 2.
Table 6-8 presents fuel savings (estimated gallons and dollars) for LDVs and
HDGs during 1977 (base), 1983, and 1987. The data indicates that properly
maintained LDVs would have saved an approximate 40.4 million gallons with dollar
savings of approximately $30.3 million in 1977. By 1983, the number of gallons
saved would be lower (28.9 million) because of increased fuel efficiency. The
dollar savings, because of lower fuel consumption, would be $21.6 million despite
an increase in vehicle population. In 1987, the number of gallons saved increases
with vehicle population growth to $31.3 million gallons at a dollar savings of $23.5
In contrast, fuel savings with HDVs shows a steady increase in number of
gallons and dollars saved from 1977 to 1987. Primarily, this is due to increas-
ing vehicle growth rate.
6.4 EFFECT ON VEHICLE PERFORMANCES AND EFFECT ON VEHICLE LIFE
The benefits associated with vehicle performance and vehicle life are
presented in Section 2. Since the impact considerations on these benefits are
difficult to quantify, no further analyses is provided beyond that presented
in Section 2.
6-10
-------
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6-11
-------
6.5 FAILURE RATE AND ESTIMATED REPAIR COSTS
The detail data associated with the analysis for repair costs are presented
in Section 2. The estimated repair costs are presented in Table 6-9.
Table 6-9. ESTIMATED AVERAGE REPAIR COSTS FORlDV AND HDV FOR
VARIOUS FAILURE RATE FOR 1983 AND 1987; IDLE-MODE
VEHICLE
CATEGORY
LDV
HDV
FAILURE
RATE(%)
30
35
50
30
35
50
1977 ($)
35.50
34.00
31.00
47.00
45.00
41.80
YEARS
1983 ($)
54.00
51.00
46.50
70.50
67.50
61.50
1987 ($)
70.00
67.00
61.00
92.50
88.50
80.50
aTo the closest $0.50.
The above table was based on the following assumptions:
1. An annual 7 percent inflation rate. The compound factor 1983 and
1987 is 1.50 and 1.967, respectively.
2. Average repair costs (1977) were projected from data in Section 2.
3. Uncontrolled vehicle repair costs are approximately 58 percent
higher than costs for controlled vehicles.
4. The average repair costs do not take into consideration major repairs.
The maximum repair limit is $75.
6.6 VALUE OF WARRANTY REPAIR PERFORMED
The benefits associated with the effects on the value of warranty repair
completed is difficult to quantify and no further analysis was completed
6-12
-------
beyond that presented in Section 2. Most warranty repair is completed because
of vehicle driveability problems.
The warranty failure that would be picked up in an I/M program are those
that are related to parts that are exclusively installed for emission control
purposes.
6-13
-------
Section 7
SPECIAL SUBJECTS
The Illinois EPA has designated several special in-use vehicle control
strategies. These include:
o Heavy-duty diesel vehicles
o Light-duty diesel vehicles
o First-year vehicles
The analysis covers the following considerations:
o Population characteristics
o Population size
o Emissions effects
o Cost effects
7.1 DIESEL VEHICLES
Because of visible smoke emissions, the diesel engine is widely blamed
for much of the atmospheric pollution. However, the medically harmful pollut-
ants such as carbon monoxide, benzopyrene, and aldehydes are emitted only in
low concentrations, while the oxides of nitrogen, though by no means negligible,
are present in much lower proportions than in gasoline engines. However, black
diesel exhaust smoke is readily noticeable and is a potential safety hazard.
Therefore, many studies have introduced legislation to limit such diesel smoke.
These limits are checked with opacity measurements. Diesel exhaust odor, a
further sign of malfunctioning, is another area of concern.
7-1
-------
7.1.1 Constituents in Diesel Engine Exhaust Emissions
o Black Smoke (Unburned Carbon Particles)
Unburned carbon, appearing as visible black smoke, is a clear indica-
tion of inefficient operation; as such, its elimination is a matter
of personal as well as public interest to diesel vehicle operators.
The composition of exhaust smoke has been reported between 75 and
95 percent carbon (Ref. 20) showing significant variation with engine
loading (Ref. 25)- Particle size varies in the 0.1-0.3/^m range with
smaller particles predominating. Particles in this size rage are often
associated with significant health effects.
o White Smoke
A fine mist of partly vaporized fuel and water droplets is often
produced in "cold-start" conditions or on misfire (Ref. 26). This is
white smoke and is a powerful irritant due, in part, to accompanying
aldehydes in the exhaust gases. Fortunately it is of short duration
and is of little importance in normal driving schedules. Thus, one
can distinguish between "hot" smoke (black) and "cold" smoke (white).
o Blue Smoke
Although "white" smoke and (particularly) "black" smoke have attracted
wide attention, less is known about "blue" smoke (Ref. 26). This does
not become visible until several feet from the exhaust and is probably
the result of a cooling and (ultimately) condensation process.
Precipitation of the droplets in blue smoke yields a dark amber
liquid of the viscosity of light lube oil. Mass spectrometric analysis
has shown this to be a mixture of hydrocarbons. Blue smoke droplets
are of much smaller diameter than those of white smoke or the particles
in black smoke. They represent a particular fraction of the unburned
fuel in the exhaust, viz. that fraction which will condense in the
colder conditions some feet away from the exhaust pipe. It is heaviest
at medium load, the maximum emission occurring at 40 percent rated
+ /
load with straight-run fuels,,at 60 percent with cracked fuel. At
higher engine speeds the maximum blue smoke emission occurs at lower
loads, this shift being related to exhaust temperature.
7-2
-------
o Odor
Diesel exhaust odor, although somewhat unpleasant, is not, of itself,
dangerous, except in confined situations. However, as an indicator of
some pollution, "odor" is now regulated by the State of California.
There seems to be no direct correlation between odor and pollutants;
thus odor and irritant intensity have to be assessed by panel esti-
mates. In comparative studies it has been assumed that aldehydes and
oxides of nitrogen are probably the most odoriferous constituents.
Minor sources of odor, such as organic peroxides and acids, are
unlikely to be present in sufficient quantity to contribute to
noticeable levels.
o Other Pollutants
The pollutants arousing most concern in spark-ignition engines have
been shown to be present in relatively insignificant quantities in
the case of diesel engines. Figure 7-1 shows the concentration of
some pollutants related to air/fuel ratio (Ref. 27) . Carbon content is
seen to increase rapidly at higher air/fuel ratio than carbon monoxide.
(The range of values shown covers a wide range of production model
engines.) Furthermore, concentration of 3,4-benzpyrene is of negligible
importance at acceptable air/fuel ratios, and measurable quantities
of nitrogen oxides are not detected until fuel delivery rates are
nearly twice normal values, so that pollution from either source is
unlikely to be important. Carbon, emitted as black smoke, remains
the most serious pollutant.
The diesel engine because of its high combustion ratio, better utilizes
the calorific value of injection fuel, so it needs less fuel than a gasoline
engine to develop the same horsepower, Figure 7-2 (Ref. 28).
7.1.2 Light-Duty Diesel-Powered Vehicles
The emissions of an uncontrolled diesel engine is presented in Appendix G.
In its uncontrolled form (i.e., pre-1973), the diesel engine emits 1.1 gm/km
(1.7 gm/mi) carbon monoxide, and 0.29 gm/km (0.46 gm/mi) hydrocarbons. This is
7-3
-------
E700
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is 600
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Figure 7-1. DIESEL ENGINE EXHAUST GAS CONSTITUENTS
100
OSOIIME DIESEL
24°'
^•^'''
OutpMI
A««M«OI
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Figure 7-2. COMPARATIVE ANALYSIS DIESEL VERSUS GASOLINE ENGINE MERCEDES-BENZ DATA
7-4
-------
considerably less than comparable uncontrolled gasoline engines with 1.7 gm/km
carbon monoxide andO.46 gm/km hydrocarbons.
The emissions standards for 1978 light-duty vehicles as set forth in the
Federal Register Title 40, Paragraph 86.078-8 does not differentiate between
light-duty gasoline or light-duty diesel engines. The standards set forth are:
o Hydrocarbons - 0.41 grams per vehicle mile
o Carbon Monoxide - 3.4 grams per vehicle mile
o Oxides of Nitrogen - 0.4 grams per vehicle mile
Comparing these 1978 standards to the emission values for the pre-1973
uncontrolled vehicle, one finds that the diesel engine without controls meets
the 1978 standard, except in the NO emissions.
X
An opacity standard for LDDV smoke emissions should be defined as in the
emissions standards for 1978 diesel heavy-duty vehicles.
Statistics on the number of LDDV vehicles as obtained from the manufac-
turer's sales personnel, relating to the sales of light-duty vehicles is as
follows:
Oldsmobile
o Diesels are 12.2 percent of Oldsmobile sales
o Oldsmobile has about 8.75 percent of the sales market
Mercedes-Benz
o Diesels are 65 percent of the Mercedes vehicle sales
o Mercedes-Benz sales on an allocated basis 53,000 vehicles in the U.S.
o Mercedes-Benz has about 0.5 percent of the market
On the basis of the above statistics, it is assumed that the light-duty
diesel engine has 1.3 percent of the vehicle market in the United States. The
Illinois County population based upon this percentage is presented in Table 7-1.
7-5
-------
Table 7-1. DIESEL VEHICLE TYPE DISTRIBUTION OF SELECTED
COUNTIES IN ILLINOIS (1977)
Light-Duty Vehicles Heavy-Duty Vehicles Total Vehicles
County
Champaign
Cook
DuPage
Kane
Lake
Macon
Madison
McHenry
McLean
Peoria
Rock Island
Saint Clair
Sangamon
Tazewell
Will
Winnebago
Statewide
Number
1,137
31,887
5,462
2,221
3,105
1,063
1,956
1,108
911
1,900
1,377
1,864
1,466
806
1,872
1,940
79,752
Percent
1.2
1.3
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
Number
2,112
53,619
9,417
4,382
5,206
2,224
3,381
2,077
1,607
3,270
2,359
3,066
3,239
1,339
3,945
3,444
146,422
Percent
2.3
2.1
2.1
2.4
2.1
2.6
2.6
2.3
2.1
2.1
2.1
2.0
2.7
2.1
2.6
2.2
2.2
In County
92,409
2,577,519
442,025
181,040
250,951
86,942
158,341
90,064
73,842
153,832
111,400
150,573
120,306
65,131
153,175
157,271
6,632,627
Source: 1. R.L. Polk & Company
2. J. Harms
3. Assumptions: (a) 45 percent of Heavy-duty vehicles are
diesel, HDV manufactures.
(b) 1.3 percent of LDV are diesel - data
from Mercedes-Benz and General Motors.
7-6
-------
It is evident that a well designed diesel engine, regularly maintained and
sensibly operated without overloading.will produce very little HC/CO or smoke.
The costs to perform testing of the light-duty diesel vehicle for opacity
reading only, is presented in Table 7-2. This is based on the premise that in
the case of the LDDV the primary concern is to establish that acceptable smoke
limits are not exceeded under "free acceleration" in neutral gear.
7.1.3 Heavy-Duty Diesel-Powered Vehicles
Heavy-duty diesel-powered vehicles (HDDV) as compared with its counterpart
in the gasoline-powered HD engine, feature low pollution power plants. The
emissions factors for the heavy-duty diesel-powered vehicles (pre-1973) are
presented in Appendix H. In the pre-1973 vehicles, the HDDV CO emission
factors were 28.7 gm/mi (truck) and 21.3 gm/mi (bus); 4.6 g/mi (truck) and
4.0 (bus) for HC; and 20.9 gm/mi (truck) and 21.5 gm/mi (bus) for NO . The
X
emission factors for HDGV were 188 gm/mi CO, 13.6 g/mi HC, and 12.5 g/mi NO . It
X.
is evident that the diesel emissions are considerably lower.
The EPA in 1979 promulgated new standards for the 1980 heavy-duty diesel
engines. These standards are:
o Hydrocarbons - 1.5 grams per brake horsepower
o Carbon monoxide - 25 grams per brake horsepower
o Hydrocarbons plus oxides of nitrogen - 10 grams per brake horsepower
hour
Or the following standards
o Hydrocarbons plus oxides of nitrogen - 5 grams per brake horsepower
hour
7-7
-------
Table 7-2. DIESEL VEHICLE COSTS STATE-OPERATED,
AND UNDER ACCELERATION/OPACITY TEST MODE
Light-Duty Diesel Vehicles Heavy-Duty Diesel Vehicles
County
Champaign
Cook
DuPage
Kane
Lake
Macon
Madison
McHenry
McLean
Peoria
Rock Island
Saint Clair
Sangamon
Tazewell
Will
Winnebago
Statewide
Capital
$ 308
8,641
1,480
602
842
288
530
300
247
515
373
505
397
218
507
526
21,613
Operating
$ 2,773
77 ,772
13,322
5,417
7,573
2,593
4,771
2,693
2,222
4,634
3,358
4,546
3,575
1,966
4,566
4,732
194,515
Capital
1,481
37,587
6,601
3,073
3,650
1,559
2,371
1,456
1,127
2,293
1,654
2,150
2,271
939
2,765
2,415
136,394
Operating
13,325
338,282
59,412
27,646
32,845
14,031
21,330
13,103
10,138
20,630
14,883
19,343
20,435
8,448
24,889
21,725
923,776
Assumptions:
(a) Throughput time, same as idle test for gasoline vehicle.
(b) Capital costs same as gasoline.
(c) Operation costs same as gasoline.
(d) Based upon life cycle costing for a 10-year life.
7-8
-------
o Carbon monoxide - 25 grains per brake horsepower hour
The opacity of smoke emissions from new 1979 and later model-year diesel
heavy-duty engines shall not exceed:
o 20 percent during the engine acceleration mode
o 15 percent during the engine lugging mode
o 50 percent during the peaks in either mode
The new standards are more stringent on emissions then the 1972 noted
values. The corresponding levels are difficult to interpolate because of the
certification test mode applied is in brake horsepower readings. To establish
an I/M program having gas emissions testing it will be necessary to develop
'short tests that would correlate to the FTP for heavy-duty diesel. At present,
the test would include only opacity checks. This ensures that the vehicle is
operating in a satisfactory air/fuel ratio range. The test could be measured
under "free acceleration" conditions that is, full throttle in netural gear to
give three successive similar maximum smoke readings.
The total cost for performing the opacity check is presented in
Table 7-2.
7.2 FIRST-YEAR VEHICLES
Vehicle stress inducement relative to time is presented in Figure 7-3.
This figure notes three failure rate regions. These regions are:
o The green area failures (break-in region) wherein the vehicle has a
failure rate slightly higher then the stabilized region.
o Stabilized regional ) where the failure rate is constant.
o t region (wear-out region)has a continuously increasing failure
rate.
7-9
-------
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break-in area within the manufacturers 12,000 mile
warranty and service check
Pure randomness within manufacturer:;
maintenance requirements
Time
u
Figure 7-3. FAILURE RATE REGION
7-10
-------
o t region has an increasing slope identifying high rate of failure.
This is the area of gross polluters.
In the majority of reported cases, new vehicle owners (i.e., first year)
returned their vehicles to the dealers for servicing within the warranty
period of 12,000 miles. This servicing would provide the necessary maintenance
and repairs resulting in minimum emissions.
A California CVS 75 study (unpublished) performed in 1976 on 159 LDVs and
21 LDTs resulted in the following conclusions.
o "Closely" maintained vehicles were significantly lower on CO emissions.
o Failure rates were high on only one component—the EGR valve. The
EGR valve becomes plugged with carbon residues because of tampering.
o Of the 105 1976 vehicles, 3 vehicles failed because of HC per CVS 75
test requirements and not per short test (Figure 7-4 and 7-5). The
repaired vehicles were within emission standards.
o Of these 1976 vehicles, only 11 failed the CO test under CVS 75 test-
ing. Seven would have failed a short test because of the lack of
required maintenance, that is, adjustment of carburetor or timing
(see Figure 7-2).
A review of Figures 2-13 and 2-14 of Section 2.10.3 would identify long-
and short-term vehicle deterioration.
It is generally accepted that vehicle emissions increase with time, and
that there is a corresponding change in fuel consumption as well? however, it is
also concluded that with or without an inspection and maintenance program
there would be little deterioration the first year. An SCI study showed that,
after repairs, emissions remained generally low for 6 to 9 months and then
increased to pre-repair levels after about 1 year (Ref. 14). It is assumed that
each new car is in satisfactory repair as it leaves the dealer's show room.
7-11
-------
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Presumably, vehicle emissions will run at satisfactory levels for 1 year
thereafter. It is to be noted that the manufacturers are subject to average
quality level audit of all new 49 state cars. Thus, the quality setting for
emissions on new cars are normally to FTP standards or less.
The number of new in-use vehicles is per the 49 state average of 7.5 per-
cent. The HC reductions would be negligible the first 6 months of vehicle use
(see Section 2.10.3). The Mobile 1 Program uses a 0.30 gm/mi initial emissions
factor for LDV. The EPA standard is 0.41 gm/mi.
7-14
-------
Section 8
REFERENCES
1. State of Illinois Job Titles and Salary Steps dated July 1, 1975.
2. State of Arizona, "Arizona Vehicular Emissions Inspection Program
Operation 1977", April 1978.
3. Telephone Contacts to Various Advertisement Agencies, Publishing Houses,
and Printers.
4. State of California, El Monte Air Pollution Laboratory, Telephone Communi-
cation, December 14, 1978.
5. State of Oregon, "Oregon Environmental Quality Commission, Report to the
Oregon Legislature on the Motor Vehicle Emissions Testing Program".
6. State of Illinois, Communication on the Number of Referee Stations. -They
-xejguire__one--ref eree—s^a-tion-pe^-eowvty-plus - one -extra- in—€ook—County.
7. State of Illinois Environmental Protection Agency Report, "Annual Air
Quality Report, 1977".
8. State of Illinois, "Assessment of the Need for a Motor Vehicle
Inspection and Maintenance Program in Illinois", July, 1978..
9. State of Illinois, Communication by J. Harms on Emissions Inventories
for the State of Illinois.
10. R. L. Polk and Company, Passenger Cars and Trucks, Registration Counts
Two Volumes.
ll. Appendix "N" "Emission Reductions Acheivable Through I/M of LDV, Motorcycles,
LOT and HOT." dated May 2, 1977, proposed credits, final credits are pending.
12. Kincannon, B. F. and A. H. Castaline "Information Documents on Automobile
Emissions Inspection Programs" - Final Report, EPA, Report 400/2-78-001,
February 1978.
13. Lewis E. Guthman, Mobile Source Emission Model, United States Environ-
mental Protection Agency, January 1978.
14. Olson Laboratories, "The Short Cycle Project, Effectiveness of Short
Emission Inspection Tests in Reducing Emissions Through Maintenance",
1973.
15. Elston and Cooperthwait, "New Jersey's Auto Emission Inspection Program,
An Assessment of One Year's Mandatory Operations", June 1975.
R-l
-------
16. Scott Research Laboratories, Inc., "Exhaust Emissions and Test Evaluation
of the State of California Roadside Idle Emission Inspection Program",
1975.
17. Clean Air Research Company, "An Evaluation of the Effectiveness of Auto-
mobile Engine Adjustments to Reduce Exhaust Emissions".
18. State of California Air Resources Board, "Evaluation of Mandatory Vehicle
Inspection and Maintenance Programs", August 2, 1976.
19. Northrop Corporation, "Mandatory Vehicle Emissions Inspection and Main-
tenance" V.5, 1971.
20. U.S. Environmental Protection Agency "Control Strategies for In-Use
Vehicle", November 1972.
21. Olson Laboratories, "Vehicle Emission Testing Program, Concept and Criteria
Phase, City of Chicago", February 1973.
22. State of California Unpublished Report "Evaluation of Mandatory Vehicle
Inspection and Maintenance Programs", December 1976.
23. Pacific Environmental Services, Inc., Technical Memorandum, December 1978.
24. R.A.C. Fosberry and D.E. Gee, Motor Industry Research Association Report
No. 1961/5, July 1961.
25. H. Stott and H. Bauer, M.T.Z., 18(5), 127, May 1967.
26. J. B. Durant and L. Eltinge, S.A.E. Paper No. 3R, Annual Meeting, January
1959.
27. M. Vulliamy and J. Spiers, S.A.E. Paper No. 670090, Automotive Engineer-
ing Congress, Detroit, January 1967.
28. Mercedes-Benz diesel trucks, economy data A-SP-77-211-10-CVR1 data sheet,
September, 1977.
8-2
-------
Appendix A
EMISSION CREDITS GIVEN IN THE CODE OF FEDERAL REGULATIONS
(APPENDIX N)
-------
APPENDIX A
EMMISION CREDITS GIVEN IN THE
CODE OF FEDERAL REGULATIONS
(Appendix N)
ENVIRONMENTAL PROTECTION
AGENCY
[ 40 CFR Part 51 ]
[FR.L 703^1]
APPENDIX N—EMISSION REDUCTIONS
ACHIEVABLE THROUGH INSPECTION
AND MAINTENANCE OF LIGHT DUTY
VEHICLES, MOTORCYCLES. AND LIGHT
AND HEAVY DUTY TRUCKS
AGENCY: Environmental Protection
Agency.
ACTION: Proposed rule.
SUMMARY: This Appendix presents es-
timates of potential emissions reduction
benefits which, in the judgment of the
Administrator, are likely to be achievable
through the application .of a properly
structured and managed inspection/
maintenance (I/M) program. Estimates
of emission reductions available through
retrofit programs, formerly contained in
Appendix N, have been deleted. Inspec-
^tion/Maintenance program effectiveness
is given as a function of the level of
technology, the stringency of emission
standards, the length of program opera-
tion, and the adequacy of mechanic
training. Basic program requirements are
outlined for both the centralized and
decentralized program concept. Attach-!
merit 1 provides a discussion of the mo-
deling techniques utilized to generate the
emission reduction estimates, while At-
tachment 2 provides computational ex-
amples illustrating the usage of Appen-
dix N.
FOR FURTHER INFORMATION CON-
TACT:
John O. Hidingsr, Director, Office of
Transportation and Land Use Policy
(AW-445) U.S. Environmental Protec-
tion Agency, 401 M Street SW., Wash-
ington, D.C. 20460 (202-755-0480).
ADDRESS: Submittal of Comments:
Comments upon Appendix N are re-
quested. Such comments should be di-
rected to the individual below~and post-
marked no later than August 1, 1977.
Dated: April 19,1977.
DOUGLAS M. COSTLE,
Administrator.
In Part 51, of Title 40, Code of Federal
Regulations, Appendix N is revised to
read as follows:
APPENDIX N—EMISSION REDUCTIONS AND
ACHIEVABLE THROUGH INSPECTION" AND
MAINTENANCE OP LIGHT DUTY VEHICLES,
MOTORCYCLES, AND LIGHT AND HEAVY DUTY
TRUCKS
AUTHORITY: Section 301 (a) of the Clean
Air Act as amended by section 15(c) (2) or
Pub. L. 91-604, 84 Stat. 1713; 81 Stat. 504
(42U.S.C. 1857g(a)).
1. Introduction. This Appendix presents
estimates of the potential emissions reduc-
tion benefits which, in the judgment of the
Administrator, are likely to be achievable
through the application of a properly struc-
tured and managed inspection/maintenance
(I/M) program. Since the publication of ^he
original Appendix N, new data obtained and
experience gained from operating programs
have shown the necessity for a revision to
certain portions of this document. In addi-
tion, estimates of emission reductions avail-
able through retrofit programs, formerly con-
tained In Appendix N, have been deleted.
Retrofit guidance will be placed in a separate
appendix consistent with a format to be fol-
lowed for other strategies.
To the extent possible, estimates In this
Appendix are based on empirical data. How-
ever, lack of data In several areas has neces-
sitated extrapolation of empirical data using
modeling techniques based on sound engi-
neering Judgment. A description of these
modeling techniques Is contained in Attach-
ment 1. A3 new data become available, or
as predicted extrapolations char.ge, this
Appendix will be revised and amended
accordingly.
Several definitions have been modified to
reflect their intended meaning. Mo?t impor-
tant, "Initial failure rate" has been redefined
as a "stringency factor." Hopefully, this new
definition will dispel past misapprehension
concerning the "Initial failure rate" concept.
In addition, the idle test has been slightly
redefined to reflect actual idle ernissicn test-
ing currently being used.
The minimum requirements of an I-'M
program are defined. Those programs u-hicti
are contemplating the use of a private garage
I/M program should note the special require-
ments necessary to obtain the basic emission
reduction credits.
- Emission reductions for light duty vehicles
are estimated not only for the first rear of
an I/M program but also for subsequent years
since modeling has shown that the reduction
benefits can increase with time. Additional
emission reductions are estimated for those
programs wMch include twlce-a-year mspec-"
tion and special mechanic training. Estimates
of emission reductions resulting from I/M
programs for light-duty trucks, heavy-duty
trucks, and motorcycles are also given.
Certification data and recent surveillance
data indicate that I/M effectiveness may be
greater (especially for carbon monoxide) for
catalyst equipped In-use vehicles than-for
pre-catalyst vehicles. By the time many I/M
programs are fully implemented, catalyst-
equipped vehicles will dominate the vehicle
mix. Estimates are therefore given for the ef-
fectiveness of I/M on such vehicles, despite
the limited data base at the present time.
Tables 1 through 5 summarize the emis-
sion reductions obtainable from I/M pro-
-------
grams. The actual benefit obtained by any
state or region implementing a well-designed
program may exceed the emissions reduc-
tions listed. Such higher reductions, how-
ever, would have to be shown through an
adequate source surveillance study.
2. Definitions, a. "Outpoint" rheans the
level of emissions which discriminates be-
tween those vehicles requiring emission-re-
lated maintenance and those that do not.
b. "Federal Test Procedure" (FTP)—A se-
quence of testing utilized by the Agency to
measure vehicle exhaust emissions over a
typical urban driving cycle.
c. "Heavy-duty vehicle" means for the
purpose of this Appendix, a gasoline fueled
motor vehicle whose GVW is greater than
8,500 pounds.
-
11
8
20
?3
33
37
b. Subsequent years program credit. The
following additional (to Table 1) credits are
applicable to vehicles which have undergone
more than one inspection by the beginning
of the calendar year of interest. These cred-
its are not applicable to programs having
Inspection Intervals of longer than one year.
For a model year group of vehicles, the ap-
propriate credit is selected on the basis of
the specific number of Inspections that the
group has incurred by the beginning of the
calendar year of Interest. The credit is then
added to the appropriate first year credit
above. Credits are applicable to both tech-
nology level cases, to the idle and loaded
tests, and to all stringency factor programs.
TABLE 2.—Subsequent years program credi
Number of
2
3
4 '.,
5
6
7
8 or more...
Additive credit
HC (percent) CO (percent)
7
14
20
25
20
Si
36
R
n
19
»
rt
Sll
35
c. Semi-annual 1/M program credit. A
credit of 0.2 percent per subsequent semi-
annual inspection may be added, up to 15
times, to the first year (Table 1) credits lor
those programs requiring semi-annual in-
spection. This credit is applicable at all strin-
gency factors for both He and CO, idle and
loaded tests, and both technology levels.
d. Mechanic training program credit. The
following additional credits may be taken
for the presence of an adequate program of
mechanic training.1 Table 3 provides the
basic credits for mechanic training, while
Table 4 lists the appropriate credits to be
added to Table 3 credits for subsequent
years of program operation. The sum of Table
3 and 4 credits is then to be added to the'
basic credit computed from Tables 1 and 2.
TABUS 3.—Mechanic training first year
Credits
*• Technology I
factor HC
0.10
.20
.SO
.40
.50
(percent)
1
3
4
6
7
CO
(percent)
5
/
9
8
7
Technology H
' IIC
(percent)
3
5
4
1
1
CO
(percent)
7
10
10
t
5
Number of inspections
Stringency
factor
3 of more
1IC CO HC CO
(percent) (percent) (percent) (percent)
0. 10
.20
.30
.40
.50
3
4
6
5
3
3
8
5
5
2
15
10
9
5
3
18
15 '
9
5
2
Technoloyy 11
Stringency
0.10
.20
.30
.40
.50
Number of inspections— 2 or more
IIC (percent)
10
8
2
1
1
CO
(per
4
2
1
3
1
cent)
The above Table 4 credits are applicable to
vehicles which have undergone more than
one inspectioji by the beginning of the calen-
dar year of interest. For a modal year group
of vehicles, the appropriate credit Is se-
lected on the basis of the technology level
of the vehicles, the number of Inspections
the vehicles have Incurred by the beginning
of the calendar year of Interest, and the
stringency factor of the I/M program. The
credit is then added to the appropriate, first
year mechanic training credit (Table 3) and
the result is added to the basic credit cal-
culated from Tables 1 and 2. Credits are ap-
plicable to both the Idle and the loaded test.
Inspection/maintenance approaches are
Expected to be applicable to heavy duty
gasoline fueled trucks and motorcycles, as
well as light duty vehicles.
a. Emission reductions for motorcycles and
light duty trucks. -The estimated, emission
redxiotions for tills group of vehicles are the
same as those given in Tables 1 through 4
for Technology I light duty vehicles,
b. Emission reductions for heavy duty
trucks. Estimated emission reductions due
to X/M for gasoline fueled heavy duty ve-
hicles, using either an idle or loaded emis-
sions test are cs follows:
TABLE 5.—'Heavy ditty vehicle I/A/ credit3
Stringency
factor
' 0.20
.30
.40
.50
IIC (percent)
11.4
12.3
15.6
17.2
CO (percent)-
8.3
9.2
10.5
12.0
'The "adequacy" of a mechanic training
program will, for the present, be determined
on a case-by-case basis. Guidelines will be
issued in the future it found to be feasible.
Analysis of data (generated by the City of
New York under EPA grant) on 65 trucks-
Indicate that I/M is a potentially viable emis-
sion reducing strategy. The estimated emis-
sion reductions given above are based on
these limited data. No data on the deteriora-
tion of trucks with or without I/M are avail-
able. The assumption utilised to develop
Table 5 is that the average yearly effective-
ness is one-half of'the Initial benefit achieved
as a result of a tune-up.
A-2
-------
r - 5. Basic program requirements. Tbere are
""• two basic types of operation which may be
utilized for an I/M program, namely a cen-
tralized Inspection system (government or
contractor operated) and a decentralized in-
spection system (private commercial ga-
• rages). In order to obtain full emission
. reduction benefits for either a centralized
or decentralized Inspection system, certain
minimum requirements are established,
•which if not met, will result in assessed emis-
sion reductions lower than those listed to
Tables 1 through 5 of this Appendix.
a. Program requirements—Minimum' for
ail programs.
J. Provisions for regular periodic inspec-
tion (at least annually) of all vehicles for
which emissions reductions are claimed.
lj. Provisions to ensure that failed vehi-
cles receive the maintenance necessary to
achieve compliance with the inspection
standards. The basic method Is to require
that falling vehicles pass a retest following
maintenance.
iii. Provisions for quality control. The
reliability of the inspection system and
equipment accuracy must be ensured. This
•will' include routine maintenance, calibra-
tion and inspection of all I/M equipment,
end routine auditing of inspection results.
b. Minimum, decentralized program re-
quirements. In order to receive the basic
emission reduction benefits for a decentral-
ized I/M program, the following require-
ments must be Included in addition to pro-
visions listed in Section 5(a).
i, Provisions for the licensing of inspec-
tion' facilities which insure that the facility
has obtained, prior to licensing, analytical
instrumentation v/hich has been approved
for use by the appropriate governing agency.
A representative xjf the facility must have
received instructions in the proper use of
the instruments and in vehicle testing
methods. The facility must agree to maintain
record', to collect signatures of operators
whose vehicles have passed inspection, and
to EUbrr.it to inspection of the facility.
ii. Records required to be maintained
should include the description (make, year,
license number, etc.) of each vehicle in-
spected, and its emissions test results. Rec-
ords must also be maintained on the calibra-
tion of testing equipment.
iii. Copies of these inspection records
should be submitted on a periodic basis to
the governing agency for auditing.
iv. The governing agency should inspect
each facility at least once every 90 days to
check the facilities' records, check the cali-
bration of the testing equipment and ob-
serve that proper test procedures are fol-
lov,-ed.
v. The governing agency should have an
effective program of unannounced/unsched-
uled inspections both as a routine measure
and as a complaint investigation measure. It
is also recommended that such Inspections
be used to check the correlation of instru-
ment readings among inspection facilities.
c. Motorcycle and heavy duty truck -pro-
•gram, requirements. An acceptable I/M pro-
gram for motorcycles and trucks must in-
clude the same provision specified in Section
5 for light duty vehicles. In addition, n source
.•surveillance program, such as discussed in
"Section 6(c) is strongly recommended for any
-emission reduction estimates for motorcycles
' and heavy duty vehicles. The test procedures
and program design for the evaluation of
emission redxictions should be reviewed In
advance by EPA. The source surveillance pro-
gram can include an assessment of emission
.-deterioration at the option of a state. With-
"out such en assessment, the assumption will
t>e rnadc that average yearly effectiveness is
of the initial benefit found.
6. Additional Topics—Emission reductions.
A. Idle \js. locidsd testing. Although idle and
loaded testing do not necessarily fall a
mutally inclusive set of vehicles, latest avail-
able data indicate no overall difference in HC
and CO emission reductions between the two
tests. The available data do indicate that the
loaded test can be more effective in reducing
emissions than the idle test, but only if me-
chanics are extensively trained in the proper
use of loaded test diagnostic information. For
this reason, no additional credit is given for
loaded mode testing. The loaded emission
test does, however, have the potential to
measure oxides of nitrogen from automobile
emissions and can therefore be a valuable
strategy in areas where there is a defined
NOx problem.
b. Tampering inspection. Additional an-
nual reductions in emissions can be achieved
from, a program of tampering inspection, in
conjunction with emissions inspection. The
amount of reduction credited will be a func-
tion of the sophistication and complexity of
the tampering inspection and the training of
the Inspectors. To obtain these reductions
there must be inspection and maintenance
for tampering along with emission I/M. Any
plans for tampering inspection should be re-
viewed with EPA In advance in order to esti- .
mate the potential benefits.
c. Added benefits—source surveillance pro-
gram. It is possible that well designed and
managed I/M programs -will achieve greater
reductions than those estimated in this Ap-
pendix. This can occur because deterioration
rates and other factors may be different for
specific geographic areas or'because the serv-
ice Industry is doing a better job than esti-
mated or because public maintenance habits
improve significantly In response to the pro-
gram.
To overcome the uncertainty associated
with the above it Is recommended that a
source surveillance program be performed.
The results of such a program would allow
states and areas to update the emission re-
duction benefit for I/M as clata. become avail-
able. Such source surveillance studies can
determine three tey pieces of information:
the initial reduction which vehicles can
achieve In the first year of a program as a
result of inspection and repair, the change in
lifetime vehicle emission deterioration which
can be credited to yearly inspections, and an
accurate location specific emission inventory
prior to I/M implementation.
An I/M program has the potential to
change both the first year emission rate and
the lifetime deterioration curve. Since a
source surveillance program needs to be care-
fully designed to adequately evaluate benefits
attributable to I/M, states are encouraged to
review source surveillance study designs with
regional EPA offices before beginning such
programs. Technical guidance for program
design and sizing of test samples will be
available from EPA.
In the absence of a source surveillance pro-
gram, states required to submit transporta-
tion control plans must use the estimates
contained in this Appendix In the deter-
mination of emission reductions from in-
spection/maintenance programs. In addition,
current and projected emission factors sup-
plied by EPA must be used in these deter-
minations, unless substantiating justifica-
tion for other factors is provided.
At the present time, EPA is looking at the
possibility of using short Inspection tests to
determine both percent emission reduction
due to inspection and maintenance, and
emission deterioration of vehicles over time.
The ability to use short tests to determine
percent emission reductions due to mainte-
nance will "depend upon the correlation of
the short test with the Federal Test Proce-
dure, Additional source surveillance imple-
mentation information will become avail-
able as current analyses are completed.
d. Alternative approaches. Maintenance-
oriented programs that employ approaches
other than emission testing may be capable
of achieving emission reductions for in-use
motor vehicles. Such approaches, including
mandatory maintenance procedures and en-
gine parameter Inspection, will be acceptable
only If sufficient data are provided to justify
the emission reductions estimated.
e. Program alterations. Alternations to
program design during the course of an I/M
program will be evaluated on a case-by-case
basis. Such alternations might Include:
change from an Idle test, after several years
of use, to a loaded test; change from annual
inspection, after several years of use. to a
semiannual inspection.
•t. Outpoint variations. For a given strin-
gency factor (which Is based on both hydro-
carbons and carbon monoxide), individual
cutpoiuts for hydrocarbons and carbon mon-
oxide can be varied In a theoretically infinite
number of ways. The reductions given in this
Appendix assume that there is a particular
relationship between hydrocarbon and car-
bon monoxide cutpolnts. This relationship,
though considerably more complex than
mentioned here, can be generally stated as,
for Technology I vehicles, two carbon mon-
oxide failures for each hydrocarbon failure,
and for Technology H vehicles, three car-
bon monoxide failures for each hydrocarbon
failure. It is possible that an area's particu-
lar pollution problem may call for I/M cut-
points that result in substantial deviations
from the HC/CO relationships implicit In
this Appendix. At the State's or local area's
request, EPA will review the program's cut-
point structure, and make adjustments to
emissions reduction credit as necessary.
g. High altitudes, California. All emission
reductions estimated In this section are also
applicable to high altitude areas and for ve-
hicles equipped for use in California.
h. Oxides of nitrogen.' It has not been
shown that maintenance directed at reduc-
ing HC and CO emissions has a significant
impact on oxide of nitrogen (KOx) emis-
sions. All available data show very minor In-
creases or decreases in NOx levels. It has
already been cited (Section 6(a)) that a
loaded test is capable of detecting high NOx
emitters. Maintenance procedures end an
ensuing control strategy to reduce XOi emis-
sions, based on I/M, are therefore conceiva-
ble. To the extent that tampering is directed
toward KOx emission controls, a good enti-
tampcring program, can reduce IsCx emis-
sions.
ATTACHMENT 1
DESCRIPTION' OP THE SIMULATION MO3EL
Introduction. Empirical data from ongoing
inspection/maintenance (I/M) prosrams has
shown that mandatory inspection and.
maintenance will result In significant air
quality benefits. Increased future benefits are
to be expected as such programs become
stabilized, i.e., the vehicle population has.
been subject to I/M requirements during its
full lifetime. Currently available data, how-
ever, is somewhat limited In Its ability to
estimate these future benefits quantitatively.
For this reason, a mathematical model of trie
I/M process has been developed, In which
available empirical data Is utilized to make
the model as realistic as possible. This ap-
proach was used to derive the estimates of
benefit presented in Appendix N. Two groups
of vehicles were considered, ar.d these grouns
of vehicles are designated as Technology" I
and Technology II. Technology I vehicles in-
clude all light-duty vehicles manufactured
prior to the 1975 model year that were de-
Eigned to meet pre-1975 exhaust emission
standards. Technology II vehicles include all
post-197* light-duty vehicles that -were de-
A-3
-------
signed to meet the more stringent 1975 and
later emission standards. Samples of vehicles
of the two technology levels were Input to
the model, and were taken as representative
of Technology I and Technology II vehicles
on a nationwide basis. Please note: all com-
putations In Attachments 1 and 2 are based
upon the metric system.
I. Description of the simulation model of
the inspection/maintenance process. The- I/M
process as currently conceived in the model
consists of the following events:
1. Emission deterioration from existing
levels,
2. Inspection lane testing of HC and CO
levels using the idle test to detect high FTP
emitters (NOx emissions are insignificant at
Id'.e, and therefore are not considered in the
model),
3. Maintenance or repair (resulting in lower
emission levels), if a vehicle fails the Inspec-
tion.
Each vehicle undergoes this sequence of
events throughout its useful life, which Is
assumed to be nine years, or approximately
160,000 kilometers.
The model compares average FTP emissions
In the case where an I/M program Is opera-
tional, with emissions in the case where no
I/M program exists. Benefit Is calculated as
the percent reduction in FTP emissions from
the average level in the no I/M case. FTP
emission levels art used to measure benefit
since the FTP driving cycle is assumed to be
representative of vehicle operation in urban
areas. Two types of benefit can be computed:
(1) the average benefit over a vehicle's life,
and (2) the benefit in a particular year of a
vehicle's life. Both types of benefit are de-
pendent upon the vehicle's level of emission
control technology and the number of times
the vehicle has been subjected to a manda-
tory inspection program. The average benefit
for a population of vehicles in a'given calen-
dar year is computed from the individual
technology level vehicle benefits given in Ap-
pendix N, which are of the second type. The
calculation methodology is discussed in a
later section of this Appendix.
Issues affecting estimated I/;,f benefit. Ben-
efit due to I/M depends upon the assump-
tions used to implement the simulation o!
the I/M process; that Is, the assumptions
surrounding the three events identified
above. Because the currently available data
are limited, assumptions were made regard-
ing some of the Issues that logically affect
benefit. The model reflects these assumptions,
which were based on engineering judgment.
The issues and assumptions are discussed
below.
Issue 1. Emission levels of vehicles at first
Inspection.
Concept. Benefit In the first and subse-
quent inspection years Is expected to depend
on the emission levels of vehicles at their first
Inspection. There are two ways in which dif-
ferences in the first year emission levels could
produce significant differences in benefit.
First, it is possible that for vehicles of a given
age there will be differences In the distribu-
tion of emission levels at first inspection
from one technology level to another; for ex-
ample, it might be the case that for one tech-
nology level vehicles have either very low
or very high emissions at first inspection,
whereas for another technology level vehicles
have emissions which are clumped closely
together around some average value. This
situation could possibly result in more bene-
fit for the first technology level case, even if
the same percentage of vehicles of each tech-
nology level were to fail an inspection, since
failures in the first technology level case
could result In bigger drops in emissions
percentagewise. Second, within a technology
level, different emission levels at the time of
I/M Implementation will naturally exist for
different model year vehicles, and it Is pos-
sible thai these absolute numerical differ-
ences will result in benefit (or percentage)
differences as well.
Assumptions. The first year Appendix N
benefits, and Indirectly the benefits for each
subsequent inspection year, were determined
by analyzing the emissions performance of
one-year-old cars with and without I/M.
Separate benefits v/ere calculated for the
Technology I and Technology II cases. Tech-
nology I first year benefits were based on
emissions data on 180 1973-74 models tested
In the FY '73 Emission Factor Program. Tech-
nology II first year benefits were based on
emissions data on 587 1975 models tested in
the FY '74 Emission Factor Program. These
vehicles were taken to be representative of
the nationwide mix of low altitude non-
California one-year-old Technology I and
Technology II vehicles, respectively, in terms
of mileage and maintenance characteristics.
As Appendix N benefit numbers indicate, I/M
benefits differ by technology level, at least for
CO.
With regard to different first year emission
levels that all model year vehicles, regardless
of age. obtain the same first year benefits.
This assumption is based upon the premise
that, for public acceptance reasons, the first
year pass/fail outpoints would differ with
age or model year so that all vehicles would
experience similar failure rates. Limited data
indicate that under this premise, benefits (on
a percentage-wise basis) are similar.
Issue 2. Emission deterioration.
Concept. Emission deterioration Is the
process whereby vehicle emission rates In-
crease over time from the levels at which the
vehicles were intended to emit when new.
Emission deterioration includes changes In
emissions due to normal we.ir of engine/
emission control components as well as
changes in emissions due to tampering or
poor maintenance.
Assumptions. The deterioration rates used
In the model are expressed as a percentage
of low miieage average FTP values per year.
These percentage rates are assumed to be
equal for all vehicles of a given technology
level, and are constant over time. Specifically,
the rates were taken to be 18 percent per
year for HC and 15 percent per year for CO
for Technology I vehicles; 21 percent per
year for HC and 14 percent per year for CO
for technology II vehicles. These rates are
based on data from EPA's FY '71 through
FT '74 Emission Factor Programs and repre-
sent vehicle deterioration under typical owner
maintenance practices. For a given pollu-
tant and vehicle, the model considers the
FTP rate of deterioration per year (grams/
kilometer/year) to be constant over time.
Thus, deterioration Is modeled as a linear
phenomenon. The grams/kilometer/year
value is calculated as the overall deteriora-
tion rate, (in percent) multiplied by the in-
dividual vehicle's first-year emission level.
Thus, each vehicle is considered to be an
inherently low or high emitter with respect
to each pollutant; vehicles-which have low
emissions when new will continue to have
relatively low emissions as they accumulate
mileage. Emissions of vehicles in the no I/M
case are a.jsumed to deteriorate throughout
their useful life until they reach the average
levels of pre-controlled cars at 161,000 kilom-
eters (100,000 miles).
Significant percentages of catalytic con-
verter failure may occur with increasing ve-
hicle age and if such a situation does occur,
the emission rates will Increase sharply in
later years; that is, a constant deterioration
rate assumption will not be valid. However,
the surveillance data currently available to
EPA do not cover mileage ranges extensive
enough to estimate the frequency and effect
of such failures.
The FTP deterioration rate (grams/ '
kilometer/year) Is assumed not to be af- |
fected by the existence of an I/M program. I
However. If an I/M program Is operational, j
the deterioration process is not continuous j
because deterioration Is Interrupted by an- '
nual idle test emissions inspections. If a ve-
hicle falls the idle test, its emissions are as-
sumed to be reduced via maintenance cr
repair to meet the pre-determined Idle test
standards. The FTP emissions are assumed
to be reduced correspondingly, as deter-
mined by regression relationships. Follow-
ing an I/M repair, the deterioration process
continues under the assumption that a ve-
hicle's yearly rate of deterioration (grn/km)
is unaffected by the repair that occurred.
The implication is that the inherent emis-
sions characteristics of a vehicle cannot be
improved via repair. If a vehicle passes the
idle test, its emissions are left unchanged
for the calculation of the average emission
levels (gm/km) following the round of I/M.
The deterioration process then continues
until the next annual Inspection occurs.
The idle test deterioration rate per year
(percent CO or ppm HC) is also assumed to
be constant over time for each, vehicle. Idle
test deterioration rates are determined from
FTP deterioration rates using the following
rationale: The effectiveness of I/M In reduc-
ing in-use vehicle emissions as measured
over the FTP requires that the short test
used In the inspection lane be an accurate
predictor of FTP passage or failure. One way
to ensure this Is to define the idle deteriora-
tion rate In terms of the FTP deterioration
rate. Currently In the model the assumption
is made that FTP emissions can be quan-
titatively predicted from Idle teit emissions,
and vice versa. The idle deterioration rate
for a given vehicle is determined from the
FTP deterioration rate and a regression re-
lationship. Based on data over a limited
mileage range, the relationships are assumed
to be independent of milage and mainte-
nance state.
Issue 3. Short test pa&s/fall cutpoints.
Concept. The" purpose of an inspection/
maintenance program is to reduce the emis-
sions of in-use vehicles as measured over
the FTP. A short emissions test procedure
is intended to provide a practical method
(i.e~, quick and Inexpensive) for identifying
high FTP emitting vehicles. The benefit asso-
ciated with an I/M program is dependent
on the methodology xised to determine the
short test pass/fail outpoint for each pollut-
ant from year to year. The method of de-
termining initial short test cutpoints has
varied in practice from assigning cutpoints
that are make/model specific to assigning
one set of cutpoints for all light duty vehi-
cles with similar emission control tech-
nology. The possibility of changing short test
cutpoints to reflect vehicle age is also an
important consideration.
Assumptions. The HC and CO cutpoints
on which the Appendix N benefits are based
are technology level specific. Thus, all vehi-
cles of a given emission control technology
(for example, catalyst-equipped cars) are
assumed to have the same cutpoints. Cut-
points for the first year of the sirrrulated
I/M program were set by first specifying a
stringency factor and then analyzing appro-
priate EPA emission factor data on one-year-
old vehicle.-, which were assumed to be repre-
sentative of the nationwide mix of one-year-
old vehicles. The analysis resulted in the
determination of idle test pass/fail cutpoints
for HC and O which corresponded to the
specified stringency factor (ranging from
10 percent to 50 percent). For example, if
a 30 percent stringency factor was specified,
then HC and CO idle test cutpoints were de-
termined so that approximately 30 percent
of nil vehicles would fail the idle test at
A-4
-------
' the first Inspection assuming that owners
-did not change their maintenance habits
from those typically In effect prior to the
Implementation of I/M.
- The relative stringency factors for HC and
CO were determined by assuming that a car
emitting at twice the HC FTP standard Is
equally likely to be failed as a car whlch-
is emitting at twice the CO FTP standard.
This assumption Is only one of an Infinite
number or ways that relative HC and CO
stringency factors could be weighted to
achieve the' specified overall stringency fac-
tor. For example, since more AQCRs exceed
ambient oxidant emission standards than ex-
ceed ambient CO standards, a car at twice
the HC FTP emission standard could be con-
sidered equally likely to fail as a car which
Is- at four times the CO FTP standard. The
result of the weighting criterion which was
applied is that at stringency levels beZow
30 percent, the large majority of vehicle
failures can be attributed to high CO emis-
sion levels; even though, significant percen-
tages of HC failure are detected at strin-
gency levels of 40 percent and above, HC
failure Is never as high, as CO failure, per-
centagewise.
One of the model's critical assumptions
with regard to cutpoint specification is that
the first year cutpoints continue to be used
year after year to determine which vehicles
will pass or fall the idle test. One implication
of the assumption of maintaining constant
cutpoints over time is that vehicles can con-
tinue to be repaired to meet the same stand-
ards year after year, regardless of vehicle age
or mileage. In support of this assumption,
data from the 1972 and 1973 EPA In-use
Compliance Program (ITJCP) programs indi-
cate that vehicles can contlnxie to be repaired
to FTP levels well below short test levels
which represent 50 percent stringency levels.
If service Industry repair capability is as-
sumed to be minimal (as In the base case
Appendix N credits, where failed vehicles are
repaired Just to meet the idle test cutpoints),
another Implication is that the percentage of
failed vehicles Increases over time to about
twice the initial stringency factor if, as the
model assumes, significant voluntary owner
maintenance does not occur. Data from I/M
programs in New Jersey and Chicago indicate
that the failure rates of a given model year
of vehicles do not Increase significantly as
vehicles age, even though the same cutpoint
is applied. Thus, either considerable volun-
tary maintenance is occurring or mechanics
are repairing vehicles to levels significantly
better than the minimum required repair
levels.
Issue 4. Service industry repair capability.
Concept. Air quality benefit derived from
an I/M program is dependent on the ability
of the service Industry to perform the repair
work necessary to lower emissions. Depending
on the level of service Industry training, idle
emissions could be reduced Just to the cut-
points, or well below the cutpoints, poten-
tially resulting in different benefits to air
quality.
Assumptions. The base case benefits given
In Table 1 of Appendix N assume that the
service industry is capable of repairing all
failed vehicles exactly to the idle test cut-
points. Then the equivalent FTP levels are
computed so that the average urban bene-
fits can be calculated. The model assumes
that a vehicle which is failed Incorrectly on
the Idle test does not have Its FTP emissions
either raised or lowered by the repair proc-
ess. The model also assumes that a vehicle
which falls for one pollutant only will have
the other pollutant emissions lowered to the
FTP equivalent Idle standard In cases where
errors of emission occurred.
Additional benefit is predicted If mechanic
training is in effect. The model assumes that
mechanic training would result in the reduc-
tion of emissions of failed vehicles to the
FTP standards. As to the base case, the model
assumes that If a vehicle falls for one pol-
lutant only, the other pollutant will also be
reduced to the FTP standard if an error of
emission occurred. The first year credits in-
dicate a dependency on stringency factor.
For catalyst vehicles, the tendency Is for me-
chanic training to have the largest effect on
programs with stringency factors of 20 and
30 percent. This Is reasonable because the
effect of mechanic training is Jointly depend-
ent on the percent of cars failed and the de-
gree of Improvement In the FTP levels of
repaired vehicles resulting from the me-
chanic training program: If only 10 percent
of ail cars are failed initially, then only 10
percent of all cars are repaired so that even.
an apparently significant increased reduction
due to mechanic training will be somewhat
dampened by the fact that a good percentage
of the remaining cars ere undoubtedly high
FTP emitters which simply were not caught.
If, on the other hand, 60 percent are failed
and the FTP standards In gmtm are approx-
imately equal to the FTP levels correspond-
ing to the more stringent Idle test cutpoints
additional benefit due to mechanic training
would be insignificant. For precatalyst CO,
the tendency described above, although less
apparent, still seems to be present. However,
precatalyst HC exhibits a. tendency for me-
chanic training to nave an Increasing effect
with, increasing stringency factor. The tend-
ency Is explained by the fact that for the
data which were input to the computer pro-
gram, the HC FTP standards In gin/km vras
significantly lower than the FTP level cor-
responding to the icUe test HC cutpoint, even
at stringencies of 40 to 50 percent. As a re-
sult, an increased percentage of failed ve-
hicles continued to produce Increased benefit
due to mechanic training.
The model assumes that owner tampering
following the sequence of events: failure of
the idle test, vehicle repair, and subsequent
passage of the Idle test, does cot occur. Since
motorists frequently attribute driveability
problems to properly-functioning emission
control devices, this assumption may be
somewhat unrealistic unless mechanics be-
come more knowledgeable about the trade-
OS's between performance and emission rates.
However, a good estimate of the frequency
and eSect of owner tampering (either with
or without EM) is not available at the present
time. Moreover, the benefit credits given la
Appendix N require the existence of an ef-
fective anti-tampering program.
Issue 5. Frequency of Inspection.
Concept. Since emission deterioration is
modeled to occur continuously over time, the
frequency of Inspection determines the ex-
tent of -vehicle deterioration between Inspec-
tions. The more frequent tie inspection, the
less the vehicles deteriorate and thus tie
greater the I/M benefit.
Assumptions. For the base case benefits
given in Appendix N, inspections are modeled
to take place annually. Additional benefits
result from semi-annual inspections. The dif-
ference in benefits from the annual to the
semi-annual case is presented in section
3(c) of Appendix N.
Issue 6. Short test procedure used In th2
inspection lane. ^_"
Concept. Since toe intent of an I/M pro-
gram is to reduce the emissions of in-use
vehicles as measured over the FTP, one would
ideally be able to design a short emissions
test procedure whose results could be used
to cccuratcly predict FTP emission levels.
From a practical standpoint, the short test
procedure must be quick. Inexpensive, and
applicable to vehicles in a warmed-up
condition.
A.s~umpt\ons. Benefits presented in Appen-
dix X are based on The assumption that the
Idle test Js used in the Inspection lane. Lim-
ited analysis using the simulation model In-
dicates that benefits vising the idle test and
a loaded test are comparable since the two '
tests axe equally able to Identify high FTP
emitters. j
ATTACHMENT 2 I
METHODOLOCT FOR APPLYING APPENDIX N !
BENEFIT NUMBERS
Tables 1 and 2 of Appendix N provide the
I/M benefit numbers necessary to calculate
the estimated calendar year percent reduc- i
tion In HC and CO emissions from emission
levels expected In the absence of I/M. To
determine the percent reduction in EC and
CO emissions for a given calender year, the
Appendix N numbers must be applied' to
the scenario In question. The scenario Is
specified in determining • the following for
the calendar year i of Interest;
1. The calendar year, y, in which an I/M
program was implemented.
2. The number or percentage of vehicles
of each model year (t —12 through i) con-
tributing to the total vehicle population
(vehicles of model years earlier than i—12
should be considered as model year t—12),
3. Average vehicle kilometers traveled by
each, model year group of vehicles, ' -
4. HC and CO emission factors (grams/
kilometer) for each model year group of
vehicles, assuming I/M has never been In
effect.
The calculation of emission reduction in
kilograms for a given pollutant (HC or CO)
in calender year » is performed as follows:
£>,=
where
('it^percent reduction in err.issicr-.s for vihii-les of
model yecr (in calendar year i,-'
fi/^emi^sion factor (prams "kilometer) for vibielt-s of
model yec.r (in calendar Yc.tr i, assuming 1,-M Las
never been in effect.
«;i = averse kilometers traveled by vehicles of model
year t in calendar year if
f)(i=nti-nber of vehicles of mode! yew t in calendar
year i,
' The benefit numbers in Tables 1 through I of-\ppeu"
cix N (which represent both the. ba^e ca^e of I/M and
the case where mechanic training (mcl'or a semi-annual
program is in effect), can be used to determine 6,r by
identifying the technology level represented by vehicles
of rnodel year t and the number of inspections which
vehicles of mod•-] year t have midereone by thp begin-
ning of calendar year f. The number of inspections can
be calculated formally as the minimum of (i—y) and
(i—0 for an annual I/M program, where, i is the calendar
year of interest, y is the year in which I/M was imple-
mented, snd t is the model year. It is assumed that the
maximum number of ajvnual inspections for vehicles ol
all model years will be ei^ht. For purposes of calculating
benefit, model yejr vehicles which bavo undergone nioro
than eipht inspections should be treated as if only ci^ht.
have been undergone.
The calculation of benefits In percent,'
Bi, In calendar year i requires one further
step:
!i=100
where the definitions cf m, n, and e are as •
above. ;
If only the percent reduction is of Interest, !
rather than the kilograms, the following al- ,
ternative calculation of Bt can be used: !
f -
S b>ie,tmltp.,
n _ -KI/V 1 = 1—12
where b, e, and 111, are defined r.s above, and ;j
Is the fraction of vehicles on the road In
calendar year £ which are of model year f.
The calculation of the scenario's reduced
emission factor (grams.'k!!ometer) in calcn-
A-5
-------
dar year i as a result of, I/M, Is performed as
follows:
100
where F,, e,i, mi; and n,i are as defined above. (Replace-
ment cf ii.i ivitli p.i will yield the same numerical results).
Appendix N can also be used to compute
the average percentage benefit of I/M for a
given vehicle over Its useful life, which is
essumed to be nine years or approximately
160.000 kilometers and represents eight an-
nual I/M Inspections. If the vehicle is of
model year t and I/M began in calendar
year y, this percent reduction In emissions
for a specific pollutant is computed as
follows:
(*+8
*o~\
k=t
t+S
vhere
k - calendar years covering Hie useful life of a ve-
hicle of model year (; fc=f, t-f 1, • * *, f+S,
&£>( = percent reduction in emissions for vehicles of
model year t in calendar year fc,3
ti.i=emisaion factor fcrams/kiloTneter) for vehicles of
model year ( in calendar year fc, assuming I/.M
has never been in elTect.
»u,i=.iverage kilometers traveled by vehicles of model
year t in calendar year t.
' The benefit numbers in Tables 1 through 4 of Ap-
pendix -N" (which repres-nt both the base case of I/M and
the case where mechanic training and/or a semi-annual
program is in effect), can be used to determine 6*.., by
identifying the technology level represented by vehicles
of model year t and the number of inspections which
vehicles of jr.odel year ( have undergone by the b.'glnmnj
of calendar year fr. The number of inspections (for calen-
dar \viirs aft cr calendar year y) can be calculated formally
»5 the minimum of (k— f) and (t— 0 for an annual 1/M
program, where y is the. jear in which I/M was imp'e-
uieiued, t is the mod"! year, and £ is the calendar year.
Note that 6i,i-0 for /: less thai or equal to y.
Nationwide estimates of the number of
vehicles of each model year in the calendar
year of interest, and average kilometers
traveled by each model year vehicle for the
calendar year of interest can be obtained by
referring Table 1 which provides nationwide
estimates of number of vehicles by vehicle
age, and average kilometers traveled by ve-
hicle age. Nationwide estimates of emission
factors by calendar year ere available In
AP-42. Tables 2 and 3 provide, for illustrative
purposes only.' sample emission factors for
calendar years 1977-1930 in format to be
utilized in the upcoming revision of AP-42,
Supplement 5.
Examples of the application of the meth-
odology for calculating benefit.
Specification of scenario for problem, ex-
amples 1 and Z. Ths nationwide mix of vehi-
cles by age and average VKTs, as given In
AP-42, applies. An I/M program with a 40
percent stringency factor was Implemented in
1973, and vehicles one-year-old or older were
tested by the end of calendar year 1973.
Problem 1. Determine the present reduc-
tion In emissions for HC and CO in CY 1977,
assuming that the I/M inspections are an-
nual, and that no mechanic training program
Is In effect.
Solution. The percent reduction, Bn, can
be calculated from the formula:
xioo,
-
<=77-12
reduction In emissions for vehicles of
model year t In calendar year 1977 (obtained from
Appendix N),
f;7.!=eniission factor fern/Ion) for vehicles of model
year t In calendar year 1977, assuming I/M has
never been in effect (obtained from AP-4J),
ro.-7.i=3veraf[a kilometers traveled by vehicles o( model
year t in calendar year 1977 (obtained from
Prr.i = fraction of total vehicles on the the road in
calendar year 1977 which are of model year t
(obtained from AP-42).
Note that the denominator of Brr b the usual AP-42
typ* calculation of emission factors.
The following tables detail the calculation
of both the numerator and denominator of
B- forHCand CO:
N'u- Penom-
t brr. i /:.: i i;.'rr, t p;; ( mera- iiutoF
(pei cent) tor product
product
1977 0 0.9 2.56 0.0*1 0 1.S8
1*»76-. .. 16 1.1 2!.2 .110 .47 2.93
1975 23 1.2 22.5 .107 .66 2.89
1974.. 24 2.9 21 1 .106 1.56 6 43
1673.. .. 30 3.4 198 .102 2.04 6.80
HC 1972.'. 30 3.7 IS. 2 .f>.« 1.94 6.40
1971 30 4.1 166 Oivi 1.80 599
1970 . . 30 4.5 15.1 .077 1.57 5.23
1969 30 49 11.7 .CM 1.29 4.30
1903 SI) 5.3 12.2 .04'J .95 3.17
Pre-1368.. 30 61 10.8 .120 2.37 7.96
H 65 54.07
HC: J?r;=(H.7/54.1)Xl.'X3=.27.
Nu- Pt-noni-
t fa. t m. i m-. i p-.-. i rnera- inator
(percent) tor pioduct
product
1977 0 11.7 25.6 OKI 0 305
1976 33 16.6 2!. 3 .110 14.6 44.2
1975 41 136 22.5 .107 13.4 44.8
1974. 34 35.3 21.1 .106 26 S 7S 9
1973 33 30.5 19.6 A<<2 SO.O 7'J. 0
CO 1972.. 33 43.7 13.2 .096 L'9.0 76.3
l«7l 38 47.0 16.6 .OsS 26.6 70.0
1970 . - - 3.3 52.1 15.1 .077 -'".0 60.6
1969 33 56.3 137 .034 IS 8 -19-1
]'>W 33 60.5 12.2 .049 13.7 3S 2
Pre-lMS.. 38 77.5 10 S . 12y 33.2 100.4
239 1 670.3
CO: B77=(239.1,'670.3)X1.00=.36
Problem 2. Determine the percent reduc-
tion in emissions, B~, for HG and CO in
CY 1977, assuming that the inspections are
annual and that an adequate mechanic
training program. Is in effect.
Solution. The method used for Problem 1
applies. Only the o—,i numbers will differ to
reflect the presence of an adequate program
of mechanic training. The following tables
detail the calculation of both numerator and
denominator of Bn for HC and CO:
• " Nu- Penom-
i bn t m t ">:T < P" i m*ra- inotor
(percent) tor product.
product
1977 0 0.9 25.6 0.091 0 1.87
1976 17 1.1 24.2 .110 .50 2.93
1075 25 12 22 5 .107 .72 2.S9
1974 35 2.9 21.1 .106 2.27 6.49
1973 41 3.4 19.6 .102 2.79 6. SO
HC1972. 41 3.7 13.2 .008 2.65 6.46
1971 41 4.1 16.6 .OSS 2.46 5.99
1970 41 4.5 15.1 .077 2.15 5.23
1969 41 4.9 13.7 .064 1.76 4.30
1968 41 53 I9 2 Gi9 1 30 3. 17
Pre-1998.. 41 6.1 10.8 .130 3.24 7.91
19.84 55.04
HC:Bn=UW54.0)Xl.=.37.
Nu- Uenom-
* fa. t tn, i inn. i jm. i mera- Inator
(percent) tor product
product
1977 0117 25 6 0 081 0 TO 5
1976. 40 IQ 6 212 110 17 7 44 2
1975 51 Is 6 **> 5 107 °*) 8 41 8
197* 47 35 3 *>l I 106 37~ 1 73~9
1973 51 39 5 19 6 \(y> 40 3 79
CO 1972.. 51 43.7 13.2 .096 Ss!o 763
1971 . . 51 47 9 16 8 OS8 35 7 70
1970 51 5J 1 15 1 077 30 9 6" 6
1U69 51 56 3 1J 7 CIH- 25 2 49 4
1963 51 60.5 12.2 .0*9 . 13.5 30 2
Pre-1963.. 51 77.5 10.8 .120 SI. 2 100.4
318.3 670.3
•- CO: ^;;=(31S.." '670.3; X1.00-.4S.
Specification of scenario for problem ex-
ample 3. The nationwide mix of vehicles by
age and average VKT, as given In AP-43. ap-
plies. An I/M program with a 30% stringency
factor was implemented In calendar year
1980, and vehicles one year old or older were
tested by the end of calendar year 1980. The
program is annual and no mechanic training
program Is in effect. Since the emissions
characteristics of 1978 and later model year
cars are unknown. It will be assumed that
the initial year emissions from these vehicles
will be the same as that determined for
1975 mods! year vehicles by the Agency's
Emission Factor Program; namely, .87
gm./km. HC and 14.7 gm./km. CO. Also, It
will be assumed that 1978 and later model
year vehicles deteriorate at the same rate
as 1975-77 models; namely, .17 gm/km./yr.
HC and 1.95 gm./km./yr. CO.
Problem 3. Determine the percent reduc-
tion In emissions. Bt.,, for HC and CO in
calendar year 1990, and the resulting reduced
emission factors for HC and CO for calendar
year 1990.
Solution. To calculate #„,, the method used
in the solutions to Problems 1 and 2 applies.
The following tables detail the numerical
calculation of both numerator and denomi-
nator of BM for HC and CO.
Nit- Denom-
t DM. ( r«. t 77!w. i p«. i rnera- inator
(per tor product
cent) product
1990 0092560 031 0 187
19S9 . ,.- 9 1.1 24.2 .110 .26 2.93
19 W -16 1.2 22.5 107 48 2,89
19S7 23 1.4 21.1 .106 .72 313
1035 29 1.6 19.6 .102 .93 3 20
1945 34 17 18 2 .096 1 01 2 97
TIC 19J4-. 39 71.9 16.6 .088 1.08 2.73
1983 43 20 15.1 .077 S3 233
19S2 ,. 45 2.2 13.7 .064 .86 1 93
1031 45 2.4 12.2 .049 65 1 44
19SO . 45 2.4 10.8 .033 .38 .86
Pre-1980,. 45 2.4 10.8 .087 1.01 2.28
8.34 23.58
HC: /*,-CW/2M>X1.00-.».
Nu- peuom-
t 6». i tw, t '"». t P». t mera- inator
(per- tor product
cent) product
1900 ... 0 14.7 25.6 0.081 0 30.5
1^39 28 166 24. 2 .110 lt)4 442
1938 36 18.6 22.5 .107 16.1 44.8
19S7 43 20.6 21.1 .106 198 461
1QS6 47 22.5 19.6 .102 21 1 45 0
10S5 51 24.5 18.2 .096 218 428
CO 1934- 55 28.4 16.6 .088 21.2 33.6
1933 53 28.4 15.1 .077 192 S! 0
1^32 63 30.3 13.7 .064 16.7 268
19S1 63 32.3 12.2 .019 12 2 19 3
1940 6.5 32.3 10.8 .033 7.3 11 5
Pre-1980.. 63 32,3 10.S .087 19.1 30.3
188.9 412.7
CO: BB-(18«.9/412.7)X1.00=.45.
A-6
-------
- To calculate the reduced emission factors
for HC and CO, the following formula can
be used: '
TABLE 2.—Emigfion /actors /or ligfd-duly,
gasoline-powered vehicles (o.\tUm6biles)
(low atiittide, non-California)
•~ -r • • -
1(
30-A
90
X
«VI-W-1
ew.i
*.,*.,
.'/ '^ 100 " 90
The following tables detail the calculation
of the numerator and denominator:
t
1990 ,
1989
1987--.
1985 -
EC 19S4..
19*2
1!»80 ... .
Pre-1%0..
• HC: (£,
t
19S9.".--."-
1W7IIILII
co iGs4~
19S3
issTriiin
I9SO
Pre-1 9SO. .
'K.I
0.9
1.1
1.2
1.4
1.6
1.7
1.9
2.0
2.2
2.4
2.4
2.4
P).-.
tui
14.7
16.6
IS 6
20.6
">•' 5
24.5
2fi. 4
2S. 4
30. 3
32.3
32 3
32.3
Numeral or
'"•o.i P«o i product
25.6 0.081
24.2 .110
22.5 .107
21.1 .106
19. 6 . 102
18.2 .0%
16 6 . OgS
15.1 .077
13. 7 . 064
12. 2 . 049
10.8 .033 -
10.8. .087
71 X28'3
' X18.3
=].12p/tm.
.Virtin
»"M.I ;)« i l>™<3
25.6 0
21.2 ,
22. 5 .
21.1
19. 6
IS. 2 ,
10.6
15.1 .
13.7 ,
12.2
10.8
10.8
OS1
.110
.107
.106
.102
M6
.OSS
.077
!()!9
.01!
2.07
2.93
2.89
3.13
3.20
2.97
2.78
2.32
1.93
1.43
2^25
2S.76
Tutor
net
SO. 5
41.2
'44. 8
40.1
45.0
42.8
as. 6
3M.O
1 1». 3
11.5
30.3
rotor
product
1.87
2.68
2.41
2.24
2.00
1.75
1.46
1.18
.88
.60
.36
.94
18.33
mtor
product
2.07
2.06
2.41
2.24
2 00
1.46
1.40
1.16
.88
.60
.36
.94
Model
Pre-1968
1963
1969
1970.
1971
1972
1973
1974 . . .
1975
1976
1977
TABLF 3 •
gasoline-p
' ' (low aUiiu
Carbon monoxide, grams "Kilometer;
calendar year—
1977
77.5
60.5
56.3
52.1
47.9
43.7
».5
35.3
la-6
16.6
14.7 .
. 1978 1979 I960
77.5 77.5
60.5 60.5,
60.5 60.5
56. 5 ' 60. a
52.1 56.5
47.9 52.1
43.7 47.9
39.5 43.7
20. 6 22. 5
IS. 6 3fl 6
16.6 Is 6
Eiii.if,s,ion fa>
offered vehi
;df, iwn-Cal\
77.5
610.5
60.' 5
56.5
56.5
47^8
24.5
22.5
20.6
dors for liglti-du/y,
ides (aut,
in years
1
2
3
4
5
6
7
8
9
10
11
12+
Fraction of
vehicles
O.OS1
.110
.107
.108
.102
.«-6
.oss
.077
.061
.049
.033
.OS7
Average annual
kilometers driven,
in thousands
25.6
24.2
22.5
21.1
J9.6
18.2
16.6
, 15.1
' 13.7
12.2
10.8
10.8
Source: AP-ii
A-7
-------
Appendix B
SHORT TEST EMISSIONS STANDARDS AS RELATED
TO FEDERAL CVS TESTING
-------
Appendix B
SHORT TEST EMISSIONS STANDARDS AS RELATED
TO FEDERAL CVS TESTING
The correlation attributes between short test programs and FTP tests for
noted gaseous emissions for model year 1975 are presented in Figures B-l,
B-2, B-3, B-4, B-5, and B-6. In setting pass/fail limits in a mandatory
inspection program using modal testing, it is required to set concentration
standards that relate in a logical manner to the Federal Constant Volume
Sampling (CVS) test procedure.
U.S. Environmental Protection Agency (EPA) report "Evaluation of Restora-
tive Maintenance on 1975 and 1976 Light-duty Vehicles in Detroit, Michigan"
(Ref. 5) presented emission test results for individual vehicles for test
types noted in Table B-l. This data is plotted in the graphs as noted above
for idle and loaded mode. The data, along with its statistical analysis,
indicates a low level of correlation. Superimposed on the graph is a Federal
Test Procedure to short test procedure regression relationship established by
the EPA (Williams, 76).
Table B-2 presents correlation coefficient for short-test emission measure-
ment procedures on a California 1972 Idle Inspection Fleet Test Program.
-------
CO
2
o
xe
O
X
a
h-
u.
to
N.
CO
Fi g. B-I
HC Emissions
Idle Mode
too
3 3P CUE ( AVERAGE HGH A LOW
) FFM HC
LU
_l
i
***
V)
5
O
Fig. s-2
NOX Emissions
Idle Mode
a.
K
U.
IO
K
a
100 too
2 SP CUE TEST NOX t PPM )
B-2
-------
o
Fig. B-3
HC Emissions
Key Mode
AVERAGE KEYMOOE MC ( PPM )
CD
§
X
2
Fig. B-4
NO Emissions
^
Key Mode
200 * eoo too tooo - 1200 1*00
AVERAGE KETfMCCe NOXC NO XC ( PPM~>
B-3
-------
TO
8 •»
t
*0
Fig. B-5
CO Emissions
Idle Mode
1.0 IO
2 S> CUE TEST CO < PCT >
§
O
O so
Fig. B-6
CO Emissions
Key Mode
AVERAGE KEYMC06 CO ( PCT J
B-4
-------
Table B-l. TEST TYPES
TEST
EMISSIONS
READINGS
TEST PROCEDURE CHARACTERISTICS
1975 FTP
HWY FET
FED SCY
NY/NJ
KEY MODE
TWO-SPEED
IDLE TEST
FED THREE-
MODE
GMS/Mile
CMS/Mile
GMS/Mile
GMS/Mile
Concentration
ppm/pct
Concentration
ppm/pct
Concentration
ppm/pct
Defined in sections 85.076-14 through 85.075.24
of Federal Register Vol. 37, No. 221
Defined driving cycle of 10.2 miles and 765
second duration
Driving cycle of 125 second duration and .7536
miles in length and 9 modes
Driving cycle of 75 seconds duration and .2792
miles in length consisting of 7 mode
3 Steady-state operating conditions high-speed,
low speed and idle plus presoak
Nonloaded test having two speeds: idle and
2,250 rpm
Similar to Key Mode with dynamometer loads
simulating the average power as required on the
FTP under NADA weight class
B-5
-------
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-------
Appendix C
LOADED-MODE TRUTH CHART AND DIAGNOSTIC PROCEDURES
-------
Appendix
LOADED-MODE TRUTH CHART AND DIAGNOSTIC PROCEDURES
C.I TRUTH CHART USAGE
The truth chart (Table C-l) shows failure patterns resulting from various
types of malfunction or maladjustment. Also shown on the truth chart is a
general description of the probable cause of failure and diagnostic code for
each failure pattern.
The test results of failed vehicles are compared with the truth chart to
determine the correct failure pattern. The inspector then determines the
general cause of failure and refers to the appropriate diagnostic procedures,
as indicated by the diagnostic code, for a more detailed analysis of the
problem.
Example: A vehicle fails HC and CO in the idle-mode. The inspector uses
the truth chart and finds the correct failure pattern. The probable cause of
failure, in this case, is the idle air/fuel mixture is too rich, the diagnostic
code is 1. This portion of the diagnostic truth table is shown below.
DIAGNOSTIC
IDLE LOW HIGH COMMENTS/PROBABLE CAUSE OF FAILURE CODE
CO F
HC (F) Idle air/fuel mixture rich
The inspector refers to diagnostic procedure 1 and finds that a rich
air/fuel naxture at idle may be caused by one or more of the following:
-------
Table C-l. DIAGNOSTIC TRUTH CHART
TEST MODE DIAGNOSTIC
Idle Low High COMMENTS/PROBABLE CAUSE OF FAILURE CODE
NO F F Faulty ignition advance and/or EGR.
CO F
HC CF) Idle air/fuel mixture rich.
HC F HC emission fluctuate.
CO N/L CO emission normal or low.
Idle air/fuel mixture lean.
0 F F
CO ("?) F Faulty carburetion or air induction
^) F system.
("F) F Faulty spark plug(s), spark plug
HC (F) F F wire(s), or ignition components.
© F
HC (?) F F
CO (F) F F Faulty exhaust valve action -and/or faulty
rings.
a!971 through 1974 model LDV.
1975 and later model LDV.
F = Mode must fail.
(F)= Mode may also fail.
C-2
-------
o Faulty idle mixture adjustment
o PDV restriction
o Faulty air injection system (if equipped)
o Clogged carburetor idle air-bleed passages.
In addition, diagnostic procedures for determining which of the above
case causing the failure are listed. The diagnostic procedures are to be
completed in the order shown. This will help to insure that the simplest,
quickest and least costly repair will be found to resolve the problem. The
repairs are then performed per the manufacturer's specifications.
Diagnostic Procedure 1 - Idle A/F Mixture Rich
The following procedures are to be completed in the order shown. Refer
to service manuals for specific repair information.
Diagnosis
Rich A/? mixture at only idle can be caused by PCV restriction, faulty
idle mixture adjustment, air inspection (if equipped), or clogged carburetor
idle air-bleed passages. Rich idle A/F mixture causes failing CO and high,
possible failing HC emission at idle. Since this malfunction occurs only at
idle, the air cleaner, carburetor choke, and carburetor mainsystems are
satisfactory.
A. Carburetor Idle Adjustment - Make a gross adjustment of idle mixture
to determine whether CO can be brought within the specification. If
CO can be corrected by adjustment, complete the final adjustments.
If not, continue with diagnosis.
B. PCV System - Test PCV valve by disconnecting tube to crankcase and
feeling for vacuum ahead of the valve at idle. Replace valve if
vacuum cannot be detected. Check all components for free flow.
Listen for clicking of valve to changes in vacuum.
C-3
-------
C. Air Injection System (if equipped) - Disconnect from air injection
pump. Feel for pressure and flow. If no flow can be detected,
service pump.
D. Clogged Idle Air-Bleed Passages - If CO cannot be corrected by one
of the above, carburetor must be rebuilt.
Diagnostic Procedure 2 - Idle A/F Mixture Lean
Diagnosis
Lean idle A/F mixture can be caused by excessive air leaking into the
engine at idle or too lean an idle screw adjustment. Lean A/F mixture results
in normal or low' CO emissions (may be less than 1 percent) and high fluctuating
HC emissions. High HC emissions can also be caused by grossly advanced
ignition timing.
A. Gross Lean Adjustment of Idle Mixture - If idle CO emissions are
less than 0.5 percent, richen idle mixture to determine if HC emis-
sions can be brought within specification. If they can, then perform
ADJUSTMENT.
B. Vacuum Leak - Inspect for vacuum leaks in the induction system by
spraying a heavy hydrocarbon onto the carburetor body and intake
manifold. Idle speed will increase and engine idle will smooth out
if vacuum leaks are present. Check for loose or missing vacuum
hoses. Check PCV ventilation valve to determine if it is stuck in
full flow position.
C. Ignition Timing - Check timing and advance with timing light. Check
dwell with oscilloscope.
Diagnostic Procedure 3 - Faulty Carburetion
Diagnosis
C-4
-------
Faulty carburetion results in excessive carbon monoxide emissions during
low and high cruise and may contribute to excessive idle emissions. Faulty
carburetion causes excessive quantities to fuel to be supplied to the engine.
It may also be due to problems with the air induction system rather than the
carburetor itself.
A. Air Cleaner - Inspect air cleaner element. Replace if CO emissions
at 2,500 rpm with and without air cleaner element installed change
more than 1 percent CO.
B. Carburetor Choke - Check to ensure that the choke is not stuck
partially closed. Repair or adjust if not fully open at normal
engine temperature.
C. Carburetor Main System - With air cleaner removed and choke open,
measure CO emissions at 2,500 rpm. Carburetor main system is satis-
factory if CO emissions decrease to less than one half of idle CO
emission level.
D. Fuel Pump Pressure - Check for excess fuel pressure. If excess
pressure is present, check for restricted fuel return line and pump
bypass valve.
Diagnostic Procedure 4 - Faulty Spark Plug, Spark Plug Wire, or Ignition
Components
Diagnosis
Spark plug, spark plub wire or ignition component failures resulted in
secondary ignition misfire in at least one cylinder producing very high HC
emissions during low and high cruise and may contribute to high idle emissions,
A. Conduct an ignition system diagnosis. Check for erroded plugs,
incorrect gap, disconnected or open wires, crossfire, distributor
cap and rotor condition.
C-5
-------
B. Conduct a diagnosis of the following components to determine where
the expected fault is occurring; coil, condenser, distributor advance
mechanisms, electronic ignition components.
Diagnostic Procedure 5 - Faulty Exhaust Valve Action/Bad Rings
Diagnosis
Faulty exhaust valve action and/or bad rings result in producing high HC
and CO emissoins in low and/or high cruise. This condition may also cause
high HC and/or CO emissions in the idle-mode.
A. Conduct a compression check to determine if the valve(s) are seating.
The compression check should show no more than 20 percent variation
from highest to lowest cylinder and be within the manufacturer's
recommended specification.
B. If the compression check is not satisfactory, perform a cylinder
leak down test to determine whether the rings or valves are at
fault.
Diagnostic Procedure 6 - Faulty Ignition Advance and/or EGR
Diagnosis
On NO system equipped vehicles, either original equipment or retrofit
equipment, the ignition advance is modified to inhibit NO formation. Many
X
vehicles also employ exhaust gas recirculation (EGR). These systems may
malfunction resulting in excessive NO emissions during the low or high cruise.
A. Determine whether emission failure is due to NO system malfunction.
x
Repair or replace the system according to applicable service proce-
dures. Check for plugged EGR valves or disconnected hoses.
B. Check for vacuum or mechanical advance malfunction, incorrect basic
timing or dwell. Repair and adjustment of the timing malfunction
may correct the NO failure.
1 x
C-6
-------
Appendix D
EMISSIONS-RELATED PARTS LIST
-------
Appendix D
EMISSIONS-RELATED PARTS LIST.
The following list of components are examples of emissions-related parts.
I. CARBURETION AND AIR INDUCTION SYSTEM
A. Air Induction System:
1. Temperature sensor elements
2. Vacuum motor for air control
3. Hot air duct and stove
4. Air filter housing and element
B. Emissions Calibrated Carburetors:
1. Metering jets
2. Metering rods
3. Needle and seat
4. Power valve
5. Float circuit
6. Vacuum break
7. Choke mechanism
8. Throttle control solenoid
9. Deceleration valve
10. Dashpot
11. Idle stop solenoid, anti-dieseling assembly
12. Accelerating pump
13. Altitude compensator
C. Mechanical Fuel Injection:
1. Pressure regulator
2. Fuel injection pump
3. Fuel injectors
4. Throttle-position compensator
5. Engine speed compensator
6. Engine temperature compensator
7. Altitude cut-off valve
8. Deceleration cut-off valve
9. Cold-start valve
-------
D. Continuous Fuel Injection:
1. Fuel pump
2. Pressure accumulator
3. Fuel filter
4. Fuel distributor
5. Fuel injectors
6. Air-flow sensor
7. Throttle-position compensator
8. Warm-running compensator
9. Pneumatic overrun compensator
10. Cold-start valve
E. Electronic Fuel Injection:
1. Pressure regulator
2. Fuel distribution manifold
3. Fuel injectors
4. Electronic control unit
5. Engine' speed sensor
6. Engine temperature sensor
7. Throttle-position sensor
8. Altitude/manifold-pressure sensor
9. Cold-start valve
F. Air Fuel Ratio Control:
1. Frequency vlave
2. Oxygen sensor
3. Electronic control unit
G. Intake Manifold
II. IGNITION SYSTEM
A. Distributor:
1. Cam
2. Points
3. Rotor
4. Condenser
5. Distributor cap
6. Breaker plate
7. Electronic components (breakerless or electronic system)
B. Spark Advance/Retard Systems:
1. Centrifugal advance mechanism:
a. weights
b. springs
D-2
-------
2. Vacuum advance unit
3. Transmission controlled spark systems:
a. Vacuum solenoid
b. Transmission switch
c. Temperature switches
d. Time delay
e. CEC valve
f. Reversing relay
4. Electronic spark control systems:
a. Computer circuitry
b. Speed sensor
c. Temperature switches
d. Vacuum switching valve
5. Orifice spark advance control systems:
a. Vacuum by-pass valve
b. OSAC (orifice spark advance control) valve
c. Temperature control switch
d. Distributor vacuum control valve
6. Speed controlled spark systems:
a. Vacuum solenoid
b. Speed sensor and control switch
c. Thermal vacuum switch
C. Spark Plugs
D. Ignition Coil
E. Ignition Wires
III. MECHANICAL COMPONENTS
A. Valve Train:
1. Intake valves
2. Exhaust valves
3. Valve guides
4. Valve springs
5. Valve seats
6. Camshaft
B. Combustion Chamber:
1. Cylinder head or rotor housing*
2. Piston or rotor
* Rotary (Wankel) engines only
D-3
-------
IV. EVAPORATIVE CONTROL SYSTEM
A. Vapor Storage Canister and Filter
B. Vapor Liquid Separator
C. Filler Cap
D. Fuel Tank
V. POSITIVE CRANKCASE VENTILATION SYSTEM
A. PCV Valve
B. Oil Filler Cap
C. Manifold PCV Connection Assembly
VI. EXHAUST GAS RECIRCULATION SYSTEM
A. EGR Valve:
1. Valve body and carburetor spacer
2. Internal passages and exhaust gas orifices
B. Driving Mode Sensors:
1. Speed sensors
2. Solenoid vacuum valve
3. Electronic amplifier
4. Temperature-controlled vacuum valve
5. Vacuum reducing valve
6. EGR coolant override valve
7. Backpressure transducer
8. Vacuum amplifier
9. Delay valves
VII. AIR INJECTION SYSTEM
A. Air Supply Assembly:
1. Pump
2. Pressure relief valve
3. Pressure-setting plug
4. Pulsed air system
B. Distribution Assembly:
1. Diverter, relief, bypass, or gulp valve
2. Check or anti-backfire valve
D-4
-------
3. Deceleration control part
4. Flow control valve
5. Distribution manifold
6. Air switching valve
C. Temperature sensor
VIII. CATALYST, THERMAL REACTOR, AND EXHAUST SYSTEM
A. Catalytic Converter:
1. Constricted fuel filler neck
2. Catalyst beads (pellet type converter)
3. Ceramic support and monolith coating (monolith type converter)
4. Converter body and internal supports
5. Exhaust manifold
B. Thermal Reactor:
1. Reactor casing and lining
2. Exhaust manifold and exhaust port liner
C. Exhaust System:
1. Manifold
2. Exhaust port liners
3. Double walled portion of exhaust system
4. Heat riser valve and control assembly
D-5
-------