United States
Environmental Protection Agency
EPA-AA-EPSD-IM-93-1
April 1994
Air
High-Tech I/M Test Procedures,
Emission Standards, Quality Control
Requirements, and Equipment
Specifications
Final
Technical Guidance
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United States
Environmental Protection Agency
>/ EPA-AA-EPSD-IM-93-1
April 1994
Air
& High-Tech I/M Test Procedures,
Emission Standards, Quality Control
Requirements, and Equipment
Specifications
Final
Technical Guidance
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Table of Contents
Page
Table of Contents i
Introduction 1
§85.2205 Short Test Standards - IM240-Purge Test 3
(a) IM240 Emission Standards 3
(b) Transient Test Score Calculations 7
(c) Purge Test Standards 10
§85.2221 IM240 and Purge Test Procedure 11
(a) General Requirements 11
(b) Pre-inspection and Preparation 11
(c) Equipment Positioning and Settings 12
(d) Vehicle Conditioning 13
(e) Vehicle Emission Test Sequence 14
(f) Emission Measurements 17
§85.2226 IM240 Equipment Specifications 18
(a) Dynamometer Specifications 18
(b) Constant Volume Sampler 24
(c) Analytical Instruments 26
§85.2227 Evaporative System Inspection Equipment 29
(a) Evaporative Purge System 29
(b) Evaporative System Integrity Analysis System 30
§85.2234 IM240 Test Quality Control Requirements 31
(a) General Requirements 31
(b) Dynamometer 31
(c) Constant Volume Sampler 34
(d) Analysis System 36
(e) Gases 38
(f) Overall System Performance 39
(g) Control Charts 39
§85.2235 Evaporative Test System Quality Control Requirements 42
(a) Evaporative Purge Analysis System Flow Checks 42
(b) Evaporative Pressure System Check 42
§85.2239 Test Report -IM240 and Evaporative Tests 43
(a) General Test Report Information 43
(b) Tests and Results 43
§85.2231 Terms 45
(a) Definitions 45
(b) Abbreviations 45
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Introduction
This document is the successor to the July version of "High-Tech I/M Test Procedures, Emission
Standards, Quality Control Requirements, and Equipment Specifications," and you should replace your
old copy of the Technical Guidance with this one once you have noted the changes. There are relatively
few changes and many of them are more in the nature of clarifications than substantive changes.
However, some changes were necessary due to information that came to light as some states and
contractors began the process of finalizing detailed specifications and plans for their testing networks
and implementing the new tests.
The IM240 test equipment specifications have not been changed. Some clarifications were added
to the fast-pass/fast-fail logic in §85.2205(a)(4) and §85.2205(c)(2); however, the logic is the same as
described in the EPA memorandum of October 13,1993. The Speed Variation Limits in §85.2221 were
found to produce a high void test rate when applied to tests that ended before 240 seconds using the fast-
pass and fast-fail algorithms. The previously published limits apply only to tests lasting the full 240
seconds. EPA is developing limits for tests that end earlier. The provision for augmented braking in
§85.2226(a)(5)(v) has been changed to require fully automatic augmented braking on the two major
decelerations of the test and to allow it elsewhere. This was done to reduce the number of test voids that
would otherwise occur due to speed excursions in these portions of the test The purge meter
specifications in §85.2227 have been revised to better ensure the desired accuracy in the lower end of the
range, which is most important for pass/fail decisions. In addition, some revisions and clarifications have
been made to §85.3334, on quality control for IM240 test equipment
The test procedures and related requirements are presented in this document in the language and
format in which EPA intends to propose to promulgate them in the Code of Federal Regulations under
§207(b) of the Clean Air Act as official I/M tests. We project that we will publish a Notice of Proposed
Rulemaking in July of this year. No additional revisions will be made prior to proposal. Interested
parties will, of course, have the opportunity to comment on these provisions when they are proposed.
However, EPA believes that minimal changes, if any, will be made in the rule making process, given that
the test procedures and related requirements, as presented here, already reflect an understanding of the
views of the primary interested parties.
Because the coverage, language, and format of the test procedures and related requirements are
specific to EPA's plan to propose the high tech tests as 207 (b) tests, state agencies will want to extract
and reformat those portions relevant to their own needs. A state specifying equipment for state-operated
inspection stations, for example, would not need to copy all the same parts as a state preparing a request
for proposals for construction and operation of stations. Also references to "the Administrator" will
need to be changed.
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Section 85.2205(a), "IM240 Emission Standards," requires special explanation. In
§85.2205(a)(2), EPA has listed start-up standards which it currently recommends be adopted for
inspections performed in 1995 and 1996. More stringent final standards for 1997 and later are
recommended in §85.2205(a)(3). EPA recommends the looser start-up standards for the first two years
of a high-tech I/M program primarily out of concern for the transitional capability of the vehicle repair
industry to handle the number of failed cars. By 1997, repair facilities will be more adept, more may
have entered the I/M repair business, and much of the accumulated backlog of defective vehicles will have
already been repaired, allowing the IM240 standards to be tightened for greater emission reduction. EPA
advises states to retain as much flexibility to revise inspection standards during 1995 and 1996 as
possible, since local experience may indicate the advisability of either more or less stringent start-up
standards than shown in §85.2205(a) (3). In its Federal Register proposal to establish 207(b) tests, EPA
intends to propose the standards shown in §85.2205(a)(3) for use even in 1995 and 1996, since EPA
does not doubt that they satisfy the requirements for a 207(b) test However EPA will be monitoring the
situation closely as states begin testing in 1995 and to ensure that the recommended standards in this
document are producing the desired outcome and is prepared to revisit and revise these standards if
significant unanticipated problems develop. ,
Some readers have noted that this Technical Guidance document does not contain standards and
procedures for the evaporative integrity, or "pressure" test EPA has previously published the test
procedure and standards in the I/M regulation, in §51.357(a)(10) and (b)(3)(i). Requirements related to
the evaporative system integrity test will, of course, be included in the 207(b) rule making.
4/19/94 Page 2
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§85.2205
§85.2205
§85.2205 Short Test Standards • lM240-Purge Test
(a) IM240 Emission Standards
(1) Two Wavs to Pass Standards,- If the corrected, composite emission rates calculated in
paragraph (b) exceed standards for any exhaust component, additional analysis of test
results shall look at the second phase of the driving cycle separately. Phase 2 shall
include second 94 through second 239. Second-by-second emission rates in grams,
and composite emission rates in grams per mile for Phase 2 and for the entire test shall
be recorded for each gas. For any given exhaust component, if the composite emission
level is equal to or below the composite standard or if the Phase 2 grams per mile
emission level is equal to or below the applicable Phase 2 standard, then the vehicle
shall pass the test for that exhaust component.
(2) Start-up Standards. Start-up standards should be used during calendar years 1995 and
1996. Tier 1 standards are recommended for 1996 and later vehicles and may be used
for 1994 and later vehicles certified to Tier 1 standards. The following exhaust
emissions standards, in grams per mile, are recommended:
(0
Light Duty Vehicles.
Model Yean
Carbon Monoxide
Oxides of Nitroaen
Composite Phase 2 Composite Phase 2
1994* Tier 1 0.80 0.50 15.0 12.0
1991-1995 1.20 0.75 20.0 16.0
1983-1990 2.00 1.25 30.0 24.0
1981-1982 2.00 1.25 60.0 48.0
1980 2.00 1.25 60.0 48.0
1977-1979 7.50 5.00 90.0 72.0
1975-1976 7.50 5.00 90.0 72.0
1973-1974 10.0 6.00 150 120
1968-1972 10.0 6.00 150 120
(ii) High-Altitude Light Dutv Vehicles.
Model Years Hydrocarbons
Composite Phase 2
1983-1984 2.00 1.25
1982 2.00 1.25
(iii) Light Duty Trucks 1 (less than
Made! Years Hydrocarbons
Composite Phase 2
1994+ Tier 1
(£3750 LVW) 0.80 0.50
(>3750LVW) 1.00 0.63
1991-1995 2.40 1.50
1988-1990 3.20 2.00
1984-1987 3.20 2.00
1979-1983 7.50 5.00
1975-1978 8.00 5.00
1973-1974 10.0 6.00
Carbon Monoxide
Composite Phase 2
60.0 48.0
75.0 60.0
6000 pounds GVWR)
Carbon Monoxide
Composite Phase 2
15.0 12.0
20.0 16.0
60.0 48.0
80.0 64.0
80.0 64.0
100 80.0
120 96.0
150 120
Composite Phase 2
2.0 (Reserved)
2.5 (Reserved)
3.0 (Reserved)
3.0 (Reserved)
6.0 (Reserved)
6.0 (Reserved)
9.0 (Reserved)
9.0 (Reserved)
10.0 (Reserved)
Oxides of Nitrogen
Composite Phase 2
3.0 (Reserved)
3.0 (Reserved)
Qftidfl flf Njtroffen
Composite Phase 2
2.0 (Reserved)
2.5 (Reserved)
3.0 (Reserved)
3.5 (Reserved)
7.0 (Reserved)
7.0 (Reserved)
9.0 (Reserved)
9.0 (Reserved)
Standards I Calculations
Page 3
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§85.2205
§85.2205
1968-1972 10.0 6.00 150 120 10.0 (Reserved)
(iv) Hieh-Altitude Light Duty Trucks 1 (less than 6000 pounds GVWR).
Hydrocarbon^
Composite Phase 2
Carbon Monoxide
Composite Phase 2
Oxides of Nitrogen
Composite Phase 2
1991+
1988-1990
1984-1987
1982-1983
3.00
4.00
4.00
8.00
2.00
2.50
2.50
5.00
70.0
90.0
90.0
130
56.0
72.0
72.0
104
3.0
3.5
7.0
7.0
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(v) Lieht Duty Trucks 2 (greater than 6000 pounds GVWR).
Model Yean
1994+ Tier 1
(<5750 LVW)
(>5750 LVW)
1991-1995
1988-1990
1984-1987
1979-1983
1975-1978
1973-1974
1968-1972
Hydrocarbons
Composite Phase 2
Carbon Monoxide
Composite Phase 2
Oxides of Nitrogen
Composite Phase 2
1.00
2.40
2.40
3.20
3.20
7.50
8.00
10.0
10.0
0.63
1.50
1.50
2.00
2.00
5.00
5.00
6.00
6.00
20.0
60.0
60.0
80.0
80.0
100
120
150
150
16.0
48.0
48.0
64.0
64.0
80.0
96.0
120
120
2.5
4.0
4.5
5.0
7.0
7.0
9.0
9.0
10.0
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(vi) High-Altitude Light Dutv Trucks 2 (greater than 6000 pounds GVWR).
Model Yean
Hydrocarbons
Composite Phase 2
Carbon Monoxide
Composite Phase 2
1991+
1988-1990
1984-1987
1982-1983
3.00
4.00
4.00
8.00
2.00
2.50
2.50
5.00
70.0
90.0
90.0
130
56.0
72.0
72.0
104
Oxides of Nitrogen
Composite Phase 2
4.5 (Reserved)
5.0 (Reserved)
7.0 (Reserved)
7.0 (Reserved)
(3) Final Standards. The following exhaust emissions standards, in grams per mile, are
recommended for vehicles tested in the calendar years 1997 and later. Tier 1 standards
are recommended for all 1996 and newer vehicles but may be used for 1984 and newer
vehicles.
(i) Light Dutv Vehicles.
MnddYean
1994+ Tier 1
1983-1995
1981-1982
1980
1977-1979
1975-1976
1973-1974
1968-1972
Hydrocarbons
Composite Phase 2
Carbon Monoxide
0.60
0.80
0.80
0.80
3.00
3.00
7.00
7.00
0.40
0.50
0.50
0.50
2.00
2.00
4.50
4.50
Composite
10.0
15.0
30.0
30.0
65.0
65.0
120
120
\ Phase 2
8.0
12.0
24.0
24.0
52.0
52.0
96.0
96.0
Oxides of Nitrogen
Composite Phase 2
1.5
2.0
2.0
4.0
4.0
6.0
6.0
7.0
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
Standards I Calculations
Page 4
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385.2205
§85.2205
(ii) High-Altitude Light Duty Vehicles.
Model Yean
1983-1984
1982
Hydrocarbons
Composite Phase 2
Carbon Monoxidq
Composite Phase 2
1.20
1.20
0.75
0.75
30.0
45.0
24.0
36.0
Oxides of Nitrogen
Composite Phase 2
2.0 (Reserved)
2.0 (Reserved)
(iii) Light Duty Trucks 1 (less than 6QQQ pounds GVWR).
Model Years
1994+Tier 1
(£3750 LVW)
(>3750 LVW)
1988-1995
1984-1987
1979-1983
1975-1978
1973-1974
1968-1972
Hydrocarbons
Composite Phase 2
Carbon Monoxide
Composite Phase 2
Oxides of Nitrogen
Composite Phase 2
0.60
0.80
1.60
1.60
3.40
4.00
7.00
7.00
0.40
0.50
1.00
1.00
2.00
2.50
4.50
4.50
10.0
13.0
40.0
40.0
70.0
80.0
120
120
8.0
10.0
32.0
32.0
56.0
64.0
96.0
96.0
1.5
1.8
2.5
4.5
4.5
6.0
6.0
7.0
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(iv) High-Altitude Light Duty Trucks 1 (less than 6000 pounds GVWR).
Model Yeara
Composite Phase 2
Carbon Monoxide
Composite Phase 2
1988+
1984-1987
1982-1983
2.00
2.00
4.00
1.25
1.25
2.50
60.0
60.0
90.0
48.0
48.0
72.0
Oxides of Nitrogen
Composite Phase 2
2.5 (Reserved)
4.5 (Reserved)
4.5 (Reserved)
(v) Light Duty Trucks 2 (greater than 6QQQ pounds GVWR).
Model Yeara
1994+Tier 1
(<5750LVW)
(>5750LVW)
1988-1995
1984-1987
1979-1983
1975-1978
1973-1974
1968-1972
Hydrocarbons
Composite Phase 2
Cartoon Monoxide
Composite Phase 2
Oxides of Nitrogen
Composite Phase 2
0.80
0.80
1.60
1.60
3.40
4.00
7.00
7.00
0.50
0.50
1.00
1.00
2.00
2.50
4.50
4.50
13.0
15.0
40.0
40.0
70.0
80.0
120
120
10.0
. 12.0
32.0
32.0
56.0
64.0
96.0
96.0
1.8
2.0
3.5
4.5
4.5
6.0
6.0
7.0
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(Reserved)
(vi) High-Altitude Light Duty Trucks 2 (greater than 6000 pounds GVWR).
Model Yeara
Hydrocarbons
Composite Phase 2
Carbon Monoxide
Composite Phase 2
1988+
1984-1987
1982-1983
2.00
2.00
4.00
1.25
1.25
2.50
60.0
60.0
90.0
48.0
48.0
72.0
Oxides of Nitrogen
Composite Phase 2
3.5 (Reserved)
4.5 (Reserved)
4.5 (Reserved)
Standards I Calculations
PageS
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§85-2205 585.2205
(4) Fast-Pass and Fast-Fail. Vehicles may be fast-passed and/or fast-failed using the
following algorithm.
(i) Beginning at second 30 of the driving cycle, cumulative second-by-second
emission levels for each second, calculated from the start of the cycle in grams,
shall be compared to the cumulative fast-fail or fast-pass emission standards for
the second under consideration. For exhaust components subject to Phase 2
standards, cumulative second-by-second emission levels calculated from second
94 forward in grams shall be compared to cumulative second-by-second fast-
fail or fast-pass Phase 2 emission standards for the second under consideration.
(ii) A vehicle shall pass the IM240 test for a given exhaust component if either of
the following conditions occur
(A) cumulative emissions of the exhaust component for the full driving
cycle are below the full cycle fast-pass standard for the second
under consideration; or,
(B) at second 94 and later, if the exhaust component is subject to
Phase 2 standards, cumulative Phase 2 emissions are below the
Phase 2 fast-pass standards for the second under consideration;
(iii) Optionally, a vehicle shall fail the IM240 test for a given exhaust component if
either of the following conditions occur.
(A) cumulative emissions of the exhaust component for the full driving
cycle are above the full cycle fast-fail standard for the second
under consideration; or,
(B) at second 94 and later, for exhaust components subject to Phase 2
standards, the following two conditions must be satisfied
simultaneously:
(i) cumulative full cycle emissions for the second under
consideration are above the minimum cumulative composite
emission level for vehicles failing the test, and
(ii) cumulative Phase 2 emissions are above the Phase 2 fast-
fail standard for the second under consideration.
(iv) Testing may be terminated when fast-pass or fast-fail criteria are met for all
subject exhaust components and for purge as described in paragraph (c)(l),
(c)(3)(ii), or (c)(3)(iii) of this section in the same second.
(v) If a fast-pass or fast-fail determination cannot be made for all subject exhaust
components and for purge before the driving cycle ends, the pass/fail
determination for each component shall be based on composite or Phase 2
emissions over the full driving cycle as described in paragraph (a)(l) of this
section.
(vi) In instances where the fast-pass and fast-fail standards converge at some point
in the driving cycle, if the vehicle has not either fast-passed or fast-failed at the
point where the standards converge, it may fast-pass if it falls below the fast-
pass standard in the next second. Otherwise the test shall continue for the
duration of the full driving cycle.
Standards I Calculations Page 6
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§85.2205
§85.2205
(b) Transient Test Score Calculations
(1) Composite Scores. The composite scores for the test or test mode shall be determined
by dividing the sum of the mass of each exhaust component obtained in each second of
the test or mode by the number of miles driven in the test or test mode. The first data
point is the sample taken from t=0 to t=l. The IM240 shall be divided into four modes
as follows:
Mode Cvcle Portion
1 0-60 seconds
2 61-119 seconds
3 120-174 seconds
4 175-239 seconds
The composite test score shall be obtained by weighting the modes by their weighting
factors, if applicable, and averaging them. The composite test value shall be calculated
by the equation in (b)(l)(i):
(i) Composite gpm
s
£ grams of emissions
sec==0
s
£ miles traveled
sec=0
(ii)
Where: s = ' duration of test in seconds for fast pass / fast fail
= 239 seconds for complete IM240
Where the composite emissions are to be calculated by weighting factors, the
equation in (b)(l)(iii) shall be used
(iii)
gprn,.
WF1*
WF3*
r si
£gramse
sec=0
si
X miles
L sec=0
T s3
£gramse
sec=s2+l
WF2*
s3
£ miles
- sec=s2+l
- s2
£gramse
sec=sl+l
s2
Smiles
i_ sec=s 1+1
r s4
WF4*
sec=s3+l
s4
£ miles
- sec=s3+l
Where: gramse
miles
si
s2
s3
s4
WF1
WF2
WF3
WF4
grams of emissions (HC, CO, and NOx)
composite grams per mile
miles traveled
60 second, or duration of test for fast pass / fast fail
119 second, or duration of test for fast pass / fast fail
174 second, or duration of test for fast pass / fast fail
239 second, or duration of test for fast pass / fast fail
weighting factor for mode 1 = (Reserved)
weighting factor for mode 2 = Reserved)
weighting factor for mode 3 = (Reserved)
weighting factor for mode 4 = (Reserved)
Standards I Calculations
Page?
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§85.2205 §85.2205
(2) Second-bv-Second Mass Calculations. The mass of each exhaust component shall be
calculated to five significant digits for each second of the test using the following
equations:
(i) Hydrocarbon mass: HCmass = Vmix*DensityHc*(HCconc/l, 000,000)
(ii) Carbon Monoxide mass: C0mass = Vmix*Densityco*(COCOnc/l. 000,000)
(iii) Oxides of Nitrogen mass:
= Vmix*DensityN02*KH*(NOXConc/l,000,000)
(iv) Carbon Dioxide mass: COzmass - Vmix*Densityco2*(C02COnc/100)
(3) Meaning of Symbols.
(i) HCmass = Hydrocarbon emissions in grams per second.
(ii) Densitync - Density of hydrocarbons is 16.33 grams per cubic foot assuming
an average carbon to hydrogen ratio of 1:1.85 at 68°F and 760 mm
Hg pressure.
(iii) HCconc = Average hydrocarbon concentration per second of the dilute
exhaust sample measured as described in §85.2226(c) (4) , and
corrected for background, in ppm carbon equivalent, i.e., equivalent
propane*3.
(A) HCconc = HCe-HQU-1/DF). Where:
(B) HCe = Hydrocarbon concentration of the dilute exhaust sample as
measured in ppm carbon equivalent
(C) HQ = Background hydrocarbon concentration of the dilution air,
sampled as described in §85.2221 (b) (5), as measured in
ppm carbon equivalent
(D) DF = 13.4 / [CO2e+(HCe+COe)*10-4], calculated on a second-
by-second basis.
(iv) Vmix = The CVS flow rate in cubic feet per second corrected to standard
temperature and pressure.
(v) C0mtas = Carbon monoxide emissions in grams per second.
(vi) Densityco = Density of carbon monoxide is 32.97 grams per cubic foot at 68°F
and 760 mm Hg pressure.
(vii) COconc = Average carbon monoxide concentration per second of the dilute
exhaust sample measured as described in §85.2226(c)(4), and
corrected for background, water vapor, and COz extraction, in
ppm.
(A) COconc = COe-COd(l-l/DF)
(B) C0e = Carbon monoxide concentration of the dilute exhaust in
ppm.
Standards I Calculations Page 8
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§85.2205 §85.2205
(D) COd = Background carbon monoxide concentration of the dilution
air, sampled as described in §85.2221 (b)(5), in ppm.
(viii) N0xmass = Oxides of nitrogen emissions in grams per second.
(ix) DensityNOZ = Density of oxides of nitrogen is 54.16 grams per cubic foot
assuming they are in the form of nitrogen dioxide at 68°F and 760
mm Hg pressure.
(x) NOxconc = Average concentration of oxides of nitrogen per second of the
dilute exhaust sample measured as described in §85.2226(c)(4),
and corrected for background in ppm.
(A) NOxconc = NOx«-NOxdU-l/DF)
(B) NOx« = Oxides of nitrogen concentration of the dilute exhaust
sample as measure in ppm.
(C) NOxd = Background oxides of nitrogen concentration of the dilution
air, sampled as described in §85.2221 (b) (5), as measured in
ppm.
(xi) KH= humidity correction factor.
(A) KH = l/[l-0.0047(H-75)].
(B) H = Absolute humidity in grains of water per pound of dry air.
(C) H = [(43.478)Rt*PdMPB-(Pd*Ra/100)]
(D) Ra = Relative humidity of the ambient air, percent
(E) Pd = Saturated vapor pressure, mm Hg at the ambient dry bulb
temperature. If the temperature is above 86° F, then it shall
be used in lieu of the higher temperature, until EPA supplies
final correction factors.
(F) PB - Barometric pressure, mm Hg.
(xii) COzmass = Carbon dioxide emissions in grams per second.
(xiii) Densitycoz = Density of carbon dioxide is 51.81 grams per cubic foot at 68°F
and 760 mm Hg.
(xiv) COzconc = Average carbon dioxide concentration per second of the dilute
exhaust sample measured as described in §85.2226(c)(4), and
corrected for background in percent
(A) C02conc = COzc-COzdd-l/DF)
(B) C02d = Background carbon dioxide concentration of the dilution
air, sampled as described in §85.2221 (b) (5), as measured in
percent
Standards I Calculations Pa8* 9
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§85.2205 §85.2205
(c) Purge Test Standards
(1) Total Flow Method- The vehicle shall pass the purge test when the total volume of
flow exceeds one standard liter. If total volume of flow is less than 1.0 standard liter at
the conclusion of the transient driving cycle, the vehicle shall fail. Any measurement
below the noise specification in §85.2227(a)(2)(vi) shall not be included in the total
flow calculation.
(2) Total Flow Method Fast-Pass and Fast-Fail. Vehicles may be fast-passed and/or fast-
failed using the following algorithm.
(i) Beginning at second 30 of the driving cycle, cumulative second-by-second
purge levels for each second, in liters, shall be compared to the cumulative fast-
pass and fast-fail purge standards for the second under consideration.
(ii) A vehicle shall pass the purge test if cumulative purge levels are above the fast-
pass standard for the second under consideration;
(iii) A vehicle shall fail the purge test if cumulative purge levels are below the fast-
fail standard for the second under consideration;
(iv) Testing may be terminated when a fast-pass or fast-fail decision has been made
for purge and for all subject exhaust components in the IM240 as described in
paragraph (a)(4)(ii), (a) (4) (iii) or (a)(4)(v) of this section.
(v) If a fast-pass or fast-fail decision cannot be made for purge and for all subject
exhaust components before the driving cycle ends, the pass/fail determination
for purge shall be based purge levels over the full driving cycle as described in
paragraph (c)(l) of this section.
(3) Flow Rate Method. (Reserved)
Standards I Calculations Pa8e
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§85.2221
§85.2221 IM240 and Purge Test Procedure
(a) General Requirements
( 1 ) Data Collection The following information shall be determined for the vehicle being
tested and used to automatically select the dynamometer inertia and power absorption
settings:
(i) Vehicle type: LDGV, LDGT1, LDGT2, HDGT, and others as needed,
(ii) Chassis model year,
(iii) Make,
(iv) Model,
(v) Gross vehicle weight rating, and
(vi) Number of cylinders, or cubic inch displacement of the engine.
(2) Ambient Conditions. The ambient temperature, absolute humidity, and barometric
pressure shall be recorded continuously during the transient or as a single set of
readings up to 4 minutes before the start of the transient driving cycle.
(3) Restart. If shut off, the vehicle shall be restarted as soon as possible before the test and
shall be running at least 30 seconds prior to the transient driving cycle.
(b) Pre-inspection and Preparation
(1) Accessories. All accessories (air conditioning, heat, defogger, radio, automatic traction
control if switchable, etc.) shall be turned off (if necessary, by the inspector).
(2) Lsaka. The vehicle shall be inspected for exhaust leaks. Audio assessment while
blocking exhaust flow or gas measurement of carbon dioxide or other gases shall be
acceptable. Vehicles with leaking exhaust systems shall be rejected from testing.
(3) Operating Temperature. The vehicle temperature gauge, if equipped and operating, shall
be checked to assess temperature. If the temperature gauge indicates that the engine is
not at normal operating temperature, the vehicle shall not be fast-failed and shall get a
second-chance emission test if it fails the initial test for any criteria exhaust component.
Vehicles in overheated condition shall be rejected from testing.
(4) Tire Condition. Vehicles shall be rejected from testing if the tire cords, or bubbles, cuts,
or other damage are visible. Vehicles shall be rejected that have space-saver spare tires
on the drive axle. Vehicles may be rejected that do not have reasonably sized tires.
Vehicle tires shall be visually checked for adequate pressure level. Drive wheel tires
that appear low shall be inflated to approximately 30 psi, or to tire sidewall pressure, or
manufacturers recommendation. Tires of vehicles being tested for the purposes of
program evaluation under §51.353(c) shall have their tires inflated to tire sidewall
pressure.
(5) Ambient Background. Background concentrations of hydrocarbons, carbon monoxide,
oxides of nitrogen, and carbon dioxide (HC, CO, NOX. and C02, respectively) shall be
sampled as specified in §85.2226(b) (2) (iv) to determine background concentration of
constant volume sampler dilution air. The sample shall be taken for a minimum of 15
seconds within 120 seconds of the start of the. transient driving cycle, using the same
analyzers used to measure tailpipe emissions except as provided in paragraph (0(3) of
this section. Average readings over the 15 seconds for each gas shall be recorded in the
test record. Testing shall be prevented until the average ambient background levels are
less than 20 ppmC HC, 35 ppm CO, and 2 ppm NOx.
Test Procedures Page 11
-------
§85.2221 §85.2221
(6) Sample System Purge. While a lane is in operation, the CVS shall continuously purge
the CVS hose between tests, and the sample system shall be continuously purged when
not taking measurements.
(7) Negative Valuep. Negative gram per second readings shall be integrated as zero and
recorded as such.
(c) Equipment Positioning and Settings
(1) Purge Equipment If an evaporative system purge test is to be performed:
(i) The evaporative canister shall be checked unless the canister is inaccessible. A
missing or obviously damaged canister shall result in failure of the visual
evaporative system check or rejection from testing (rejection shall be counted as
failure for purposes of reporting to EPA).
(ii) The evaporative system shall be visually inspected for the appearance of proper
hose routing and connection of hoses, unless the canister is inaccessible. If any
evaporative system hose is disconnected, then the vehicle shall fail the visual
evaporative system check or shall be rejected from testing. All hoses
disconnected for the test shall be reconnected after a purge flow test is
performed.
(iii) The purge flow measurement equipment shall be pneumatically connected in
series between the evaporative canister and the engine, preferably on the canister
end of the hose.
(2) Roll Rotation. The vehicle shall be maneuvered onto the dynamometer with the drive
wheels positioned on the dynamometer rolls. Prior to test initiation, the rolls shall be
rotated until the vehicle laterally stabilizes on the dynamometer. Drive wheel tires shall
be dried if necessary to prevent slippage during the initial acceleration.
(3) Cooling System. Testing shall not begin until the test-cell cooling system is positione '
and activated. The cooling system shall be positioned to direct air to the vehicle cooling
system, but shall not be directed at the catalytic converter.
(4) Vehicle Restraint Testing shall not begin until the vehicle is restrained. Any restraint
system shall meet the requirements of §85.2226(a)(5)(ii). In addition, the parking
brake shall be set for front wheel drive vehicles prior to the start of the test
(5) Dynamometer Settings. Dynamometer power absorption and inertia weight settings
shall be automatically chosen from an EPA-supplied electronic look-up table which will
be referenced based upon the vehicle identification information obtained in (a)(l).
Vehicles not listed shall be tested using default power absorption and inertia settings as
follows:
Test Procedures Page 12
-------
§85.2221
§85.2221
VEHICLE
TYPE
All
All
All
All
LDGV
LDGT
LDGV
LDGT
LDGV
LDGT
NUMBER OF
CYLINDERS
3
4
5
6
8
8
10
10
12
12
ACTUAL ROAD
LOAD
HORSEPOWER
8.3
9.4
10.3
10.3
11.2
12.0
11.2
12.7
12.0
13.4
TEST
INERTIA
WOGHT
2000
2500
3000
3000
3500
4000
3500
4500
4000
5000
(6) Exhaust Collection System. The exhaust collection system shall be positioned to insure
complete capture of the entire exhaust stream from the tailpipe during the transient
driving cycle. The system shall meet the requirements of §85.2226(b)(2).
(d) Vehicle Conditioning
(1) Queuing Time. When the vehicle queue exceeds 20 minutes, a vehicle shall get a
second-chance emission test if it falls the initial test and all criteria exhaust components
are at or below 1.5 times the standard when the standards specified in §51.351(a)(7)
apply.
(2) Program Evaluation. Vehicles being tested for the purpose of program evaluation under
§51.353(c) shall receive two full transient emission tests (i.e., a full 240 seconds each).
Results from both tests and the test order shall be separately recorded in the test record.
Emission scores and results provided to the motorist may be from either test.
(3) Discretionary Preconditioning. At the program's discretion, any vehicle may be
preconditioned using any of the following methods:
(i) Non-loaded Preconditioning. Increase engine speed to approximately 2500
rpm, for up to 4 minutes, with or without a tachometer.
(ii) Loaded Preconditioning. Drive the vehicle on the dynamometer at 30 miles per
hour for up to 240 seconds at road-load .
(iii) Transient Preconditioning. After maneuvering the vehicle onto the
dynamometer, drive a transient cycle consisting of speed, time, acceleration, and
load relationships similar to that of the transient driving cycle in (e)(l) of this
section.
(4) Second-Chance Purge Testing. Vehicles that exhibit significant purge activity during
the driving cycle but do not accumulate one liter of purge shall receive a second-chance
purge test The second-chance test may be the Transient Driving Cycle or modified
sequences of shorter duration designed to rapidly produce purge activity.
Test Procedures
Page 13
-------
§85.2221
§85.2221
(e) Vehicle Emission Test Sequence
(1) Transient Driving Cvcle. The vehicle shall be driven over the following cycle:
Tune
second
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Speed
mph
0
0
0
0
0
3
5.9
8.6
11.5
14.3
16.9
17.3
18.1
20.7
21.7
22.4
22.5
22.1
21.5
20.9
20.4
19.8
17
14.9
14.9
15.2
15.5
16
17.1
19.1
21.1
22.7
22.9
22.7
22.6
21.3
19
17.1
15.8
15.8
17.7
19.8
21.6
23.2
24.2
24.6
24.9
25
Time
second
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
Speed
mph
25.7
26.1
26.7
27.5
28.6
29.3
29.8
30.1
30.4
30.7
30.7
30.5
30.4
30.3
30.4
30.8
30.4
29.9
29.5
29.8
30.3
30.7
30.9
31
30.9
30.4
29.8
29.9
30.2
30.7
31.2
31.8
32.2
32.4
32.2
31.7
28.6
25.1
21.6
18.1
14.6
11.1
7.6
4.1
0.6
0
0
0
Time
second
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
Speed
mph
0
0
3.3
6.6
9.9
13.2
16.5
19.8
22.2
24.3
25.8
26.4
25.7
25.1
24.7
25.2
25.4
27.2
26.5
24
22.7
19.4
17.7
17.2
18.1
18.6
20
20.7
21.7
22.4
22.5
22.1
21.5
20.9
20.4
19.8
17
17.1
15.8
15.8
17.7
19.8
21.6
22.2
24.5
24.7
24.8
24.7
Time
second
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
Speed
mph
24.6
24.6
25.1
25.6
25.7
25.4
24.9
25
25.4
26
26
25.7
26.1
26.7
27.3
30.5
33.5
36.2
37.3
39.3
40.5
42.1
43.5
45.1
46
46.8
47.5
47.5
47.3
47.2
47.2
47.4
47.9
48.5
49.1
49.5
50
50.6
51
51.5
52.2
53.2
54.1
54.6
54.9
55
54.9
54.6
Time
second
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
Speed
mph
54.6
54.8
55.1
55.5
55.7
56.1
56.3
56.6
56.7
56.7
56.3
56
55
53.4
51.6
51.8
52.1
52.5
53
53.5
54
54.9
55.4
55.6
56
56
55.8
55.2
54.5
53.6
52.5
51.5
50.5
48
44.5
41
37.5
34
30.5
27
23.5
20
16.5
13
9.5
6
2.5
0
(2) Driving Trace. The inspector shall follow an electronic, visual depiction of the
time/speed relationship of the transient driving cycle (hereinafter, the trace). The visual
depiction of the trace shall be of sufficient magnification and adequate detail to allow
accurate tracking by the driver and shall permit the driver to anticipate upcoming speed
changes. The trace shall also clearly indicate gear shifts as specified in paragraph
Test Procedures
Page 14
-------
§85.2221
§85.2221
(3)
Shift Schedule. For vehicles with manual transmissions, inspectors shall shift gears
according to the following shift schedule:
Shift Sequence
gear
1-2
2-3
De-clutch
1-2
2-3
3-2
2-3
3-4
4-5
5-6
De-clutch
Speed
miles per hour
15
25
15
15
25
17
25
40
45
50
15
Nominal
Cycle Time
seconds
9.3
47.0
87.9
101.6
105.5
119.0
145.8
163.6
167.0
180.0
234.5
Gear shifts shall occur at the points in the driving cycle where the specified speeds are
obtained. For vehicles with fewer than six forward gears the same schedule shall be
followed with shifts above the highest gear disregarded.
(4) Speed Excursion Limits. Speed excursion limits shall apply as follows:
(i) The upper limit is 2 mph higher than the highest point on the trace within 1
second of the given time.
(ii) The lower limit is 2 mph lower than the lowest point on the trace within 1
second of the given time.
(iii) Speed variations greater than the tolerances (such as may occur during gear
changes) are acceptable provided they occur for no more than 2 seconds on any
occasion.
(iv) Speeds lower than those prescribed during accelerations are acceptable provided
the vehicle is operated at maximum available power during such accelerations
until the vehicle speed is within the excursion limits.
(v) Exceedances of the limits in (i) through (iii) of this paragraph shall
automatically result in a void test The station manager can override the
automatic void of a test if the manager determines that the conditions specified
in paragraph (e)(4)(iv) occurred. Tests shall be aborted if the upper excursion
limits are exceeded. Tests may be aborted if the lower limits are exceeded.
(5) Speed Variation Limits.
(i) A linear regression of feedback value on reference value shall be performed on
each transient driving cycle for each speed using the method of least squares,
with the best fit equation having the form: y = mx + b, where:
(A) y - The feedback (actual) value of speed;
(B) m a The slope of the regression line;
(C) x = The reference value; and
(D) b = The y-intercept of the regression line.
Test Procedures
Page 15
-------
585-2221 §85.2221
(ii) The standard error of estimate (SE) of y on x shall be calculated for each
regression line. A transient driving cycle lasting the full 240 seconds that
exceeds the following criteria shall be void and the test shall be repeated:
(A) SE = 2.0 mph maximum.
(B) m = 0.96-1.01.
(C) r2 = 0.97 minimum.
(D) b = ±2.0 mph.
(iii) A transient driving cycle that ends before the full 240 seconds that exceeds the
following criteria shall be void and the test shall be repeated:
(A) SE= (Reserved)
(B) m a (Reserved)
(C) r2 a (Reserved)
(D) b = (Reserved)
(6) Distance Criteria. The actual distance traveled for the transient driving cycle and the
equivalent vehicle speed (i.e., roll speed) shall be measured. If the absolute difference
between the measured distance and the theoretical distance for the actual test exceeds
0.05 miles, the test shall be void.
(7) Vehicle Stalls. Vehicle stalls during the test shall result in a void and a new test More
than 3 stalls shall result in test failure or rejection from testing.
(8) Dynamometer Controller Check. For each test, the measured horsepower, and inertia if
electric simulation is used, shall be integrated from 55 seconds to 81 seconds (divided
by 26 seconds), and compared with the theoretical road-load horsepower (for the
vehicle selected) integrated over the same portion of the cycle. The same procedure
shall be used to integrate the horsepower between 189 seconds to 201 seconds (divided
by 12 seconds). The theoretical horsepower shall be calculated based on the observed
speed during the integration interval. If the absolute difference between the theoretical
horsepower and the measured horsepower exceeds 0.5 hp, the test shall be void. For
vehicles over 8500 pounds GVWR, if the absolute difference between the theoretical
horsepower and the measured horsepower exceeds 2 hp, the test shall be void.
Alternate error checking methods may be used if shown to be equivalent
(9) Inertia Weight Selection. Operation of the inertia weight selected for the vehicle shall
be verified as specified in §85.2226(a)(4)(iii). For systems employing electrical inertia
simulation, an algorithm identifying the actual inertia force applied during the transient
driving cycle shall be used to be determine proper inertia simulation. For all
dynamometers, if the observed inertia is more than 1% different from the required
inertia, the test shall be void.
(10) CVS Operation. The CVS operation shall be verified for each test for a CFV-type CVS
by measuring either the absolute pressure difference across the venturi or measuring the
blower vacuum behind the venturi for minimum levels needed to maintain choke flow
for the venturi design. The operation of an SSV-type CVS shall be verified throughout
the test by monitoring the difference in pressure between upstream and throat pressure.
The minimum values shall be determined from system calibrations. Monitored
pressure differences below the minimum values shall void the test
Test Procedures Page 16
-------
§85.2221 §85.2221
(11) Fuel Economy. For each test, the health of the overall analysis system shall be
evaluated by checking a test vehicle's fuel economy for reasonableness, relative to upper
and lower limits, representing the range of fuel economy values normally encountered
for the test inertia and horsepower selected. For each inertia selection, the upper fuel
economy limit shall be determined using the lowest horsepower setting typically
selected for the inertia weight, along with statistical data, test experience, and
engineering judgment. A similar process for the lower fuel economy limit shall be used
with the highest horsepower setting typically selected for the inertia weight. For test
inertia selections where the range of horsepower settings is greater than 5 horsepower,
at least two sets of upper and lower fuel economy limits shall be determined and
appropriately used for the selected test inertia. Tests with fuel economy results in
excess of 1.5 times the upper limit shall result in a void test
(f) Emission Measurements
(1) Exhaust Measurement The emission analysis system shall sample and record dilute
exhaust HC, CO. CO2, and NOX during the transient driving cycle as described in
§85.2226(c)(4).
(2) Purge Measurement The analysis system shall sample and record the purge flow in
standard liters per second and total volume of flow in standard liters over the course of
the actual driving cycle as described in §85.2227(a).
(3) Integrity Measurement The analysis system shall measure and record the integrity of
the evaporative system as described in §85.2227(b).
Test Procedures ?a8e
-------
§85.2226 §85.2226
§85.2226 IM240 Equipment Specifications
(a) Dynamometer Specifications
(1) General Requirements.
(i) The dynamometer structure (e.g., bearings, rollers, pit plates, etc.) shall
accommodate all light-duty vehicles and light-duty trucks up to 8500 pounds
GVWR.
(ii) Road load horsepower and inertia simulation shall be automatically selected
based on the vehicle parameters in the test record.
(iii) Alternative dynamometer specifications or designs may be allowed upon a
determination by the Administrator that, for the propose of properly conducting
an approved short test, the evidence supporting such deviations will not cause
improper vehicle loading.
(2) Power Absorption.
(i) Coefficients. The coefficients Av, By, and Cy, from vehicle track coast down
testing, and referenced in the equations in this section are those specified during
new car certification, or as specified by a vehicle class designator determined by
the Administrator. In the absence of new car certification coefficients or a
vehicle class designator, the following track coefficients in paragraphs
(a)(2)(i)(A) through (a)(2)(i)(C) of this section shall be used.
(A) Av = (0.35/50)*(TRLHP@50mph)hp/mph
(B) Bv = (0.10/2500)*(TRLHP@50mph)hp/mph2
(C) Cv = (0.55 /125,000) * (TRLHPO 50 mph) hp/mph^
(ii) Vehicle Loading. The true vehicle loading used during the transient driving
cycle shall follow the equation in paragraph (a) (2) (iii) between 10 and 60 mph.
The dynamometer controls shall set the dynamometer loading to achieve the
coast-down target time (±1 second) with the vehicle on the dynamometer using
the vehicle-specific inertia test weights. A conversion equation or table of target
time versus horsepower for the dynamometer design shall be used. Target time
shall be converted to horsepower by the equation paragraph (a) (2) (iv) or pre-
defined horsepower values may be used.
(iii) TRLHPe Obmph = {Av * Obmph} + {By * Obmph2} + {Cv * Obmph3}
Av.Bv.Cv = Coefficients specified in paragraph (a) (2) (Oof this
section for vehicle track coast down curves.
Obmph = Observed mph
TRLHP = Track Road-Load Horsepower
= Which, on a dynamometer, includes loading contributions
from the power absorber, parasitic losses, and tire/roll
interface losses.
IM240 Equipment Page 18
-------
S8"226 185.2226
(iv) Track Road-Load Horsepower =
r.>_
ET)
ET = Elapsed time for the vehicle on the road to coast down from 55 to
45 mph, and from 22 to 18 mph
ETW = Inertia weight in pounds
Vt s Initial velocity in feet/second (i.e., velocity at either 55 or 22 mph)
V2 = Final velocity in feet/second (i.e., velocity at either 45 or 1 8 mph)
(v) In practice, the true vehicle loading is derived from equations of "force" (i.e.,
F=MA). In determining vehicle load on a dynamometer, applied loads in units
of force tangential to the roll surface are not dependent on the roll diameter
used, whereas applied loads in units of torque of horsepower are dependent on
the roll diameter. The equation in paragraph (a)(2)(vi) may be used to convert
track road-load horsepower values in paragraph (a)(2)(iii) to units of force.
(vi) TRLF@ Obmph = { Af * Obmph} + {Bf * Obmph2} + {Cf * Obmph3 }
TRLF = Track Road-Load Force (in units of pounds)
Af = 375 *AV (Av in HP/mph units)
Bf = 375 *BV (By in HP/mph2 units)
Cf = 375 *CV (Cv in HP/mph3 unite)
Af , Bf, Cf = Equivalent force coefficients to the coefficients specified
in paragraph (a)(2)(i) of this section for vehicle track
coast down curves.
(vii) Range and Curve of Power Absorber. The range of power absorber at 50 mph
shall be sufficient to cover track road-load horsepower (TRLHP) values
between 6 and 35 horsepower. The absorption shall be adjustable across the
required horsepower range at 50 mph in 0.1 horsepower increments. The
accuracy of the power absorber shall be ±0.25 horsepower or ±2% of point
whichever is greater.
(viii) Parasitic Losses (General Requirements). The parasitic losses in each
dynamometer system (such as windage, bearing friction, and system drive
friction) shall be characterized between 10 and 60 mph upon initial acceptance.
There shall be no sudden discontinuities in parasitic losses below 10 mph.
Further, when added to the lowest possible loading of the power absorber
(dynamometer motoring is considered a negative load) , the parasitic losses must
be sufficiently small such that proper loading will occur between 10 and 60 mph
for a vehicle with a 50 mph track road-load horsepower value of 6 horsepower.
The parasitic horsepower losses shall be characterized either digitally in five
mph increments and linearly interpolated in-between, or the data at 10 mph
increments shall fit the equation in paragraph (a)(2)(ix) to within 2 percent of
point
(ix) PLHP = {Ap * (Obmph)} + {(Bp) * (Obmph)2} + {(Cp) * (Obmph)3}
PLHP = Dynamometer parasitic losses.
IM240 Equipment Page 19
-------
§85.2226 §85.2226
Ap, Bp, and Cp are curve coefficients necessary to properly
characterize the dynamometer parasitic losses for
the inertia weight(s) used.
(x) Parasitic Losses (Low Speed Requirements). The coast down time of the
dynamometer between 8 and 12 mph shall be greater than or equal to the value
calculated by the equation in paragraph (a)(2)(xi) when the dynamometer is set
for a 2000 pound vehicle with a track road-load horsepower of 6 horsepower at
50 mph.
ETW*(V172-Vo2)
(xi) ET = lz —
21.94 * (Af4 -i- Bf4V + Cf4V2)
V12 = 12 mph
Vg = 8 mph
V= 10 mph
Af4 = 375*A
-------
§85.2226
§85.2226
GTRL,
'Obmph = Generic Tire/Roll Interface losses at the observed mph
Where: At, Bt, and Ct are curve coefficients necessary to properly
characterize the tire/roil interface losses.
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(I)
At
Bt
Q
Atg
Btg
Ctg
At20
Bt20
Ct20
=
=
=
=
=
=
=
=
=
(O.xx/50)
(O.yy/2500)
(O.zz/ 125,000)
(O.pp/50)
(O.qq/2500)
(O.rr/ 125,000)
(O.tt/50)
(O.uu/2500)
(O.w / 125,000)
*
*
*
*
*
*
*
*
*
(GTRL®
(GTRL®
(GTRL®
(GTRL®
(GTRL®
(GTRL®
(GTRL®
(GTRL®
(GTRL®
50 mph)
50 mph)
50 mph)
50 mph)
50 mph)
50 mph)
50 mph)
50 mph)
50 mph)
hp/mph
hp/mph2
hp/mph^
hp/mph
hp/mph2
hp/mph^
hp/mph
hp/mph2
hp/mph3
(J) Where:
(a) At, Bf, and Q are curve coefficients necessary to properly
characterize the tire/roll interface losses.
(b) Atg, Btg, and Ctg are curve coefficients when using twin
8.625 inch diameter rolls.
(c) Ago* Bt20>arK^ Q20 are aave coefficients when using twin
20.0 inch diameter rolls.
(xiv) In the absence of new car certification GTRL® 50 mph or a vehicle class
designator, the GTRL® 50 mph shall be calculated
(A) by the equation in (a) (2) (xv) of this section when using twin 8.625
inch diameter rolls
(B) by the equation in (a) (2) (xvi) of this section when using twin 20.0
inch diameter rolls
(xv) GTRL® 50 mph = (-0.378193) + {(0.0033207) * (DAXWT)}
Where:
DAXWT = Axle weight on the drive tires
GTRL® 50 mph = Losses for 8.625 inch diameter roll
(xvi) GTRL® 50 mph = (reserved) + {(reserved) * (DAXWT)}
Where:
DAXWT . = Axle weight on the drive tires
GTRL® 50 mph = Losses for 20.0 inch diameter roll
IM240 Equipment
Page 21
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§85.2226 §* :26
(xiv) Indicated Horsepower. The power absorption for each test shall be s Jat
50 mph. The indicated power absorption (IMP) at 50 mph after acccunung for
parasitic and generic tire losses shall be determined by the equation in
paragraph (a)(2)(xv).
(xv)
IHP@ 5Q mph = TRLHP@ 50 mph - PLHP@ 50 mph - GTRL@ 50 mph
(xvi) In systems where the power absorption is actively controlled, the indicated
horsepower at each speed between 0 and 60 mph shall conform to the equation
in paragraph (a)(2)(xvii). Approximations for a smooth curve with no
discontinuities may be used between 0 and 10 mph.
(xvii) IHP@ Obmph = TRLHP0 Obmph - PLHPa Obmph - GTRLO Obmph
(3) Rolls.
(i) Size and Type. The dynamometer shall be equipped with twin rolls. The rolls
shall be coupled side to side. In addition, the front and rear rolls shall be
coupled. The dynamometer roll diameter shall be between 8.5 and 21.0 inches.
The spacing between the roll centers shall comply with the equation in
paragraph (a)(3)(ii) to within +0.5 inches and -0.25 inches. The parasitic and
generic tire/roll interface losses for the specific roll diameter, spacing, and
surface finish used shall be determined as indicated in paragraphs (a)(2)(viii),
(a)(2)(ix), and (a)(2)(xii) of this section as necessary to properly load vehicles
as define in paragraphs (a) (2) (ii) and (a)(2)(iii) of this section. The
dynamometer rolls shall accommodate an inside track width of 30 inches and an
outside track width of at least 100 inches.
(ii) Roll Spacing = (24.375 + D) * SIN 31.5153*
D = dynamometer roll diameter.
Roll spacing and dynamometer roll diameter are
expressed in inches.
(iii) Design. The roll size, surface finish, and hardness shall be such that tire
slippage on the first acceleration of the transient driving cycle is minimized
under all weather conditions; that the specified accuracy of the distance
measurement is maintained; and that tire wear and noise are minimized.
(4) Inertia.
(i) Mechanical Inertia Simulation. The dynamometer shall be equipped with
mechanical flywheels providing test inertia weights between at least 2000 to
5500 pounds, in increments of no greater than 500 pounds. The tolerance on
the base inertia weight and the flywheels shall be within 1% of the specified test
weights. The proper inertia weight for any test vehicle shall be selectable.
(ii) Electric Inertia Simulation. Electric inertia simulation, or a combination of
electric and mechanical simulation may be used in lieu of mechanical flywheels,
provided that the performance of the electrically simulated inertia complies with
the following specifications. Exceptions to these specifications may be allowed
upon a determination by the Administrator that such exceptions would not
significantly increase vehicle loading or emissions for the purpose of properly
conducting an approved short test
IM240 Equipment Page 22
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§85'2226 §85.2226
(A) System Response. The torque response to a step change shall be at least
90% of the requested change within 100 milliseconds after a step change
is commanded by the dynamometer control system, and shall be within 2
percent of the commanded torque by 300 milliseconds after the command
is issued. Any overshoot of the commanded torque value shall not exceed
25 percent of the torque value.
(B) Simulation Error. An inertia simulation error (ISE) shall be continuously
calculated any time the actual dynamometer speed is above 10 MPH and
below 60 MPH. The ISE shall be calculated by the equation in
§85.2226(a)(4)(ii)(C), and shall not exceed 1 percent of the inertia weight
selected (IWg) for the vehicle under test
(C) ISE = (IWs-It)/(IWs)
(D) It = Im + ^ JJ (Fm - Frl) dt
Where:
It = Total inertia being simulated by the dynamometer (kg)
It Ob force) = It (kg) * 2.2046
Im = Base (mechanical inertia of the dynamometer (kg)
V = Measured roll speed (m/s)
Fm = Force measured by the load cell (translated to the roll
surface) (N)
Frl = Road load force (N) required by TRLHP at the
measure roll speed (V)
t = Time (sec)
(iii) Inertia Weight Selection. For dynamometer systems employing mechanical
inertia flywheels, the test system shall be equipped with a method, independent
from the flywheel selection system, that identifies which inertia weight flywheels
are actually rotating during die transient driving cycle.
(5) Other Requirements.
(i) Test Distance and Vehicle Speed. The total number of dynamometer roll
revolutions shall be used to calculate the distance traveled. Pulse counters may
be used to calculate the distance directly if there are at least 16 pulses per
revolution. The measurement of the actual roll distance for the composite and
each phase of the transient driving cycle shall be accurate to within ±0.01 mile.
The measurement of the roll speed shall be accurate to within ±0.1 mph. Roll
speed measurement systems shall be capable of accurately measuring a 3.3 mph
per second acceleration rate over a one second period with a starting speed of 10
mph.
(ii) Vehicle Restraint The vehicle shall be restrained during the transient driving
cycle. The restraint system shall be designed to minimize vertical and horizontal
force on the drive wheels such that emission levels are not significantly affected.
The restraint system shall allow unobstructed vehicle ingress and egress and
IM240 Equipment Page 23
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§85-2226 585.2226
shall be capable of safely restraining the vehicle under all reasonable operating
conditions.
(iii) Vehicle Cooling. The test system shall provide for a method to prevent
overheating of the vehicle. The cooling method shall direct air to the cooling
system of the test vehicle. The cooling system capacity shall be 5400 ±300
SCFM within 12 inches (30.5 cm) of the intake to the vehicle's cooling system.
The cooling system design shall avoid improper cooling of the catalytic
convenor.
(iv) Four-Wheel Drive. If used, four-wheel drive dynamometers shall insure the
application of correct vehicle loading as defined in paragraph(a)(2) of this
section and shall not damage the four wheel drive system of the vehicle. Front
and rear wheel rolls shall maintain speed synchronization within 0.2 mph.
(v) Augmented Braking. Fully automatic augmented braking shall be used from
seconds 85 through 95 and after second 223 of the driving cycle. Fully
automatic augmented braking may be used in other deceleration periods of the
driving cycle with the approval of the Administrator. During the periods of
augmented braking the operator shall be made aware that augmented braking is
occurring and shall be trained not to use the vehicle accelerator during these
periods. It shall be automatically interlocked such that it can be actuated only
while the vehicle brakes are applied. Simultaneous engine acceleration is
systematically prevented through periodic quality assurance.
(b) Constant Volume Sampler
(1) General Design Requirements.
(i) Venturi Type. A constant volume sampling (CVS) system of the critical flow
venturi (CFV) or the sub-sonic venturi (SSV) type shall be used to collect
vehicle exhaust samples. The CVS system and components shall generally
conform to the specifications in §86.109-90.
(ii) CVS Flow Size. The CVS system shall be sized in a manner that prevents
condensation in the dilute sample over the range of ambient conditions to be
. encountered during testing. A 700 SCFM system is assumed to satisfy this
requirement The range of ambient conditions may require the use of heated
sample lines. A 350 SCFM CVS system and heated lines may be used to
eliminate condensation and to increase measured concentrations for better
resolution. Should the heated sample lines be used, the sample line and
components (e.g., filters, etc.) shall be heated to a minimum of 120° F and a
maximum of 250°F, which shall be monitored during the transient driving cycle.
(iii) CVS Compressor. The CVS compressor flow capacity shall be sufficient to
maintain proper flow in the main CVS venturi with an adequate margin. For
CFV CVSs the margin shall be sufficient to maintain choke flow. The capacity
of the blower relative to the CFV flow capacity shall not be so large as to create
a limited surge margin.
(iv) Materials. All materials in contact with exhaust gas shall be unaffected by and
shall not affect the sample (Le., the materials shall not react with the sample, and
neither shall they taint the sample as a result of out gassing). Acceptable
materials include stainless steel, Teflon®, silicon rubber, and Tedlar®.
IM240 Equipment Page 24
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§85.2226
(v) Alternative Approaches. Alternative CVS specifications, materials, or designs
may be allowed upon a determination by the Administrator, that for the propose
of properly conducting an approved short test, the evidence supporting such
deviations will not significantly affect the proper measurement of emissions.
(2) Sample System.
(i) Sample Probe. The sample probe within the CVS shall be designed such that a
continuously and adequate volume of sample is collected for analysis. The
system shall have a method for determining if the sample collection system has
deteriorated or malfunctioned such that an adequate sample is not being
collected, or that the response time has deteriorated such that the time correlation
for each emission constituent is no longer valid.
(ii) CVS Mixing Tee.
(A) Design and Effect The mixing tee for diluting the vehicle exhaust with
ambient air shall be at the vehicle tailpipe exit as in §86.109-
90(a)(2)(iv). The dilution mixing tee shall be capable of
collecting exhaust from all light-duty vehicle and light-duty
truck exhaust systems. The design used shall not cause
static pressure in the tailpipe to change such that the
emission levels are significantly affected. A change of ±1.0
inch of water, or less, shall be acceptable.
(B) Locating Device. The mixing tee shall have a device for positively locating
the tee relative to the tailpipe with respect to distance from
the tailpipe, and with respect to positioning the exhaust
stream from the tailpipeis) in the center of the mixing tee
flow area. The locating device, or the size of the entrance to
the tee shall be such that if a vehicle moves laterally from
one extreme position on the dynamometer to the other
extreme, that mixing tee will collect all of the exhaust
sample.
(iii) fly.il Fixhfl"**- For dual exhaust systems, the design used shall insure that each
leg of the sample collection system maintains equal flow. Equal flow will be
assumed if the design of the "Tee" intersection for the dual CVS hoses is a " Y"
that minimizes the flow loss from each leg of the " Y," if each leg of the dual
exhaust collection system is approximately equal in length (± 1 foot), and if the
dilution area at the end of each leg is approximately equal. In addition, the CVS
flow capacity shall be such that the entrance flow velocity for each leg of the
dual exhaust system is sufficient to entrain all of the vehicle's exhaust from each
tailpipe.
(iv) Background Sample. The mixing tee shall be used to collect the background
sample. The position of the mixing tee for taking the background sample shall
be within 12 lateral and 12 longitudinal feet of the position during the transient
driving cycle, and approximately 4 vertical feet from the floor.
(v) Integrated Sample. A continuous dilute sample shall be provided for integration
by the analytical instruments in a manner similar to the method for collecting
bag samples as described in §86.109.
(c) Analytical Instruments
1M240 Equipment Page 25
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§85.2226 §85.2226
(1) General Requirements.
(0 The emission analysis system shall automatically sample, integrate, and record
the specified emission values for HC, CO, C02, and NOx. Performance of the
analytical instruments with respect to accuracy and precision, drift, interferences,
noise, etc. shall be similar to instruments used for testing under §86 Subparts B,
D, and N. Analytical instruments shall perform in this manner in the full range
of operating conditions in the lane environment
(ii) Alternative analytic equipment specifications, materials, designs, or detection
methods may be allowed upon a determination by the Administrator, that for the
propose of properly conducting an approved short test, the evidence supporting
such deviations will not significantly affect the proper measurement of
emissions.
(2) Detection Methods and Instrument Ranges.
(i) Total Hydrocarbon Analysis. Total hydrocarbon analysis shall be determined
by a flame ionization detector. If a 700 SCFM CVS is used, the analyzer
calibration curve shall cover at least the range of 0 ppmC to 2,000 ppmC. Use
of a different CVS flow capacity shall require an adjustment to these ranges.
Appropriate documentation supporting any adjustment in ranges shall be
available. Such documentation shall also address the ability of any altered
ranges to accurately measure all cutpoints, including cutpoints for vehicles older
than those specified in §85.2205(a), that may be used in the specific I/M
program for which the altered ranges are proposed to be used. The calibration
curve must comply with the quality control specifications in §85.2234(d) for
calibration curve generation.
(ii) Carbon Monoxide Analysis. CO analysis shall be determined using a non-
dispersive infrared analyzer. If a 700 SCFM CVS is used, CO analysis shall
cover at least the range of 0 ppm to 10,000 ppm (1%). In order to meet the
calibration curve requirements, two CO analyzers may be required • one from 0
to 1000 or 2000 ppm, and one from 0 to 1% CO. Use of a different CVS flow
capacity shall require an adjustment to these ranges. Appropriate
documentation supporting any adjustment in ranges shall be available. Such
documentation shall also address the ability of any altered ranges to accurately
measure all cutpoints, including cutpoints for vehicles older than those specified
in §85.2205(a), that may be used in the specific I/M program for which the
altered ranges are proposed to be used. The calibration curve requirements and
the quality control specifications in §85.2234(4) apply to both analyzers.
(iii) Carbon Dioxide Analysis. COa analysis shall be determined using an NDIR
analyzer. If a 700 SCFM CVS is used, COa analysis shall cover at least the
range of 0 ppm to 40,000 ppm (4%). Use of a different CVS flow capacity
shall require an adjustment to these ranges. Appropriate documentation
supporting any adjustment in ranges shall be available. Such documentation
shall also address the ability of any altered ranges to accurately measure all
cutpoints, including cutpoints for vehicles older than those specified in
§85.2205(a), that may be used in the specific I/M program for which the altered
ranges are proposed to be used. The calibration curve must comply with the
quality control specifications in §85.2234(d) for calibration curve generation.
(iv) Oxides of Nitrogen Analysis. NOx analysis shall be determined using
chemiluminescense. The NOx measurement shall be the sum of nitrogen oxide
and nitrogen dioxide. If a 700 SCFM CVS is used, the NOx analysis shall
IM240 Equipment Page 26
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§85'2226 §85.2226
cover at least the range of 0 ppm to 500 ppm. Use of a different CVS flow
capacity shall require an adjustment to these ranges. Appropriate
documentation supporting any adjustment in ranges shall be available. Such
documentation shall also address the ability of any altered ranges to accurately
measure all outpoints, including outpoints for vehicles older than those specified
in §85.2205(a), that may be used in the specific I/M program for which the
altered ranges are proposed to be used. The calibration curve must comply with
the quality control specifications in §85.2234(d) for calibration curve
generation.
(3) System Response Requirements. The governing requirement for system response is
the ability of the integration system to measure vehicle emissions to within ±5% of that
measured from a bag sample simultaneously collected over the same integration period,
on both clean and dirty vehicles. Historically, continuously integrated emission
analyzers have been required to have a response time of 1.5 seconds or less to 90% of a
step change, where a step change was 60% of full scale or better. System response
times between a step change at the probe and reading 90% of the change have generally
been less than 4 • 10 seconds. Systems proposed that exceed these historical values
shall provide an engineering explanation as to why the slower system response of the
integrated system will compare to the bag reading within the specified 5%.
(4) Integration Requirements.
(i) The analyzer voltage responses, CVS pressure(s), CVS temperature(s),
dynamometer speed, and dynamometer power shall be sampled at a frequency
of no less than 5 Hertz, and the voltage levels shall be averaged over 1 second
intervals.
(ii) The system shall properly time correlate each analyzer signal and the CVS
signals to the driving trace.
(iii) The one-second average analyzer voltage levels shall be converted to
concentrations by the analyzer calibration curves. Corrected concentrations for
each gas shall be derived by subtracting the pre-test background concentrations
from the measured concentrations, according to the method in §85.2205(b).
The corrected concentrations shall be converted to grams for each second using
the equations specified in §85.2205(b) to combine the concentrations with the
CVS flow over the same interval. The grams of emissions per test phase shall
be determined using the equations in Section 85.2205(b).
(iv) When multiple analyzers are used for any constituent, the integration system
shall simultaneously integrate both analyzers. The integrated values for the
lowest analyzer in range shall be used for each second.
(v) For all constituents, the background concentration levels from the lowest range
analyzer shall be used, including the case where multiple analyzers may have
been used.
(5) Analytical System Design.
(i) Materials. All materials in contact with exhaust gas prior to and throughout the
measurement portion of the system shall be unaffected by and shall not affect
the sample (i.e., the materials shall not react with the sample, and neither shall
they taint the sample as a result of out gassing). Acceptable materials include
stainless steel, Teflon, silicon rubber, and Tedlar®-
IM240 Equipment Page 27
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§85.2226 §85.2226
(ii) Bag Ports. All analysis systems shall have provisions for reading a sample bag.
A portable pump for sampling such bags is permitted.
(iii) System Filters. The sample system shall have an easily replaceable filter
element to prevent paniculate matter from reducing the reliability of the
analytical system. The filter element shall provide for reliable sealing after filter
element changes. If the sample line is heated, the filter system shall also be
heated.
(iv) Availability of Intermediate Calculation Variables. Upon request prior to a test,
all intermediate calculation variables shall be available to be downloaded to
electronic files or hard copy. These variables shall include those that calculate
the vehicle emission test results, perform emission analyzer and dynamometer
function checks, and perform quality assurance and quality control
measurements.
IM240 Equipment Page 28
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§85.2227 ' §8
§85.2227 Evaporative System Inspection Equipment
(a) Evaporative Purge System
(1) General Requirements. The evaporative purge analysis system shall measure the
instantaneous purge flow in standard liters/minute, and shall compute the total volume
of the flow in standard liters over the transient driving cycle.
(2) Specifications. The purge flow measuring system shall comply with the following
requirements.
(0 Flow Capacity. A minimum of 50 liters per minute.
(ii) Pressure Drop. Maximum of 16 inches of water at 50 liters per minute for the
complete system including hoses necessary to connect the system to the vehicle.
(iii) Totalized Flow. 0 to 100 liters of volume
(iv) Response Time. 410 milliseconds maximum to 90% of a step change between
approximately 2 and 10 liters per minute measured with air.
(v) Accuracy.
(A) ±2.0 liters per minute between 10 and 50 liters per minute (rate)
(B) ±0.15 liters per minute between 0 and 10 liters per minute (rate)
(C) ±4% of 50 standard liters total flow volume between 10 and 50
liters total flow volume over one minute.
(D) ±1.5% of 10 standard liters between 0 and 10 liters total volume
flow over one minute.
(vi) Noise. The maximum noise shall be less than 0.001 liters per second
(vii) Calibration Gas. Air
(3) Automatic Operation. Vehicle purge flow shall be monitored with a computerized
system at a minimum sample rate of 1 Hz, shall automatically capture average (if
sampled faster than 1 Hz) second-by-second readings, and shall automatically derive a
pass/fail decision. In determining the total volume of flow, the monitoring system shall
not count signal noise as flow volume. The test sequence shall be automatically
initiated when the transient driving cycle test is initiated.
(4) Adaptability The purge flow system shall have sufficient adaptors to connect in a leak-
tight manner with the variety of evaporative systems and hose deterioration conditions
in the vehicle fleet The purge measurement system shall not substantially interfere with
purge flow.
(5) Alternative Systems. Alternative purge flow equipment, specifications, materials, or
designs, may be allowed upon a determination by the Administrator, that for the
propose of properly conducting an approved short test, the evidence supporting such
deviations will not appreciably or adversely affect the proper measurement of purge or
the proper operation of the vehicle.
Evaporative Test Equipment Page 29
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§85.2227 §85.2227
(b) Evaporative System Integrity Analysis System
(1) General Requirements. Pressure gauges or measurement devices used for this test shall
have an accuracy of ±0.3 inches of water (2% of 15) or better. Nitrogen (N2), or an
equivalent non-toxic, non-greenhouse, inert gas, shall be used for pressurizing the
evaporative system. Air may be used to pressurize the system if the state program
administrator determines that potential flammability hazards are. addressed and that N2
shall be used instead whenever temperature and pressure (and other conditions as
needed) indicate a potential for explosion.
(2) Automatic Operation. The process for filling the evaporative system, monitoring
compliance, recording data, and making a pass/fail decision shall be automatic. After
the determination that the evaporative system has been filled to the specified pressure
level, and upon initiation of the integrity test, the pressure level in the evaporative system
shall be recorded at a frequency of no less than 1 hertz until the conclusion of the test
(3) Adaptability. The system shall have sufficient adaptors to connect in a leak-tight
manner with the variety of evaporative systems and hose deterioration conditions in the
vehicle fleet
(4) Test Abort The system shall be equipped with an abort system that positively shuts off
and relieves pressure to the vehicle. The abort system shall be capable of being
activated quickly and conveniently by the inspector should the need arise.
(5) Alternative Systems. Alternative equipment specifications, materials, or designs, may
be allowed upon a determination by the Administrator that, for the propose of properly
conducting an approved short test the evidence supporting such deviations will not
appreciably or adversely affect the proper determination of system integrity or the
proper operation of the vehicle.
Evaporative Test Equipment Page 30
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§85.2234 §85.2234
§85.2234 IM240 Test Quality Control Requirements
(a) General Requirements
(1) Minimurqs.- The frequency and standards for quality control specified here are
minimum requirements, unless modified as specified in paragraph (2) of this section.
Greater frequency or tighter standards may be used as needed.
(2) Statistical Process Control. Reducing the frequency of the quality control checks,
modifying the procedure or specifications, or eliminating the quality control checks
altogether may be allowed if the Administrator determines, for the propose of properly
conducting an approved short test, that sufficient Statistical Process Control (SPC) data
exist to make a determination, that the SPC data support such action, and that taking
such action will not significantly reduce the quality of the emission measurements.
Should emission measurement performance or quality deteriorate as a result of allowing
such actions, the approval shall be suspended, and the frequencies, procedures,
specifications, or checks specified here or otherwise approved shall be reinstated,
pending further determination by the Administrator.
(3) Modifications. The Administrator may modiry the frequency and standards contained
in this section if found to be impractical.
(b) Dynamometer
(1) Coast Down Check.
(i) The calibration of each dynamometer shall be checked on a weekly basis by a
dynamometer coast-down equivalent that in §86.118-78 (for reference see EOD
Test Procedures TP-302A and TP-202) between the speeds of 55 to 45 mph,
and between 22 to 18 mph. All rotating dynamometer components shall be
included in the coast-down check for the inertia weight selected.
(ii) The base dynamometer and the base plus each prime inertia weight flywheel, if
any, shall be checked with at least two horsepower settings within the normal
range of the inertia weight
(iii) The coast-down procedure shall use a vehicle off-dynamometer type method or
equivalent If a vehicle is used to motor the dynamometer to the beginning
coast-down speed, the vehicle shall be lifted off the dynamometer rolls before
the coast-down test begins. If the difference between the measured coast-down
time and the theoretical coast-down time is greater than ±1 second on the 55 to
45 mph coast-down, official testing shall automatically be prevented, and
corrective action shall be taken to bring the dynamometer into calibration.
Official testing shall also automatically be prevented, and corrective action shall
be taken to bring the dynamometer into calibration, if the difference between the
measured coast-down time and the theoretical coast-down time for 22 to 18 mph
is greater than ±7%, or is out side of the time window calculated by
§85.2234(b)U)(iii)(A) and (B). For tests using inertia weights of 8500 Ibs. and
above, if the difference between the measured coast-down time and the
theoretical coast-down time is greater than ±10%, or is out side of the time
window calculated by §85.2234(b)(l)(iii)(A) and (B) for the 22 mph to the 18
mph coast-down, official testing shall automatically be prevented, and corrective
action shall be taken to bring the dynamometer into calibration.
IM240 Quality Control Page 31
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§85.2234 §85.2234
IW * DelV
(A) DT,
(B) DTmax
min - (A + BV + CV2 + 3.3 Ibs) * 21.937
IW * DelV
(A + BV + CV2 - 3.3 Ibs) * 21.937
(C) Where:
DTmjn = Lower coast down limit (sec)
DTmax = Upper coast down limit (sec)
IW = Inertia weight selected (Ib)
DelV = Width of coast down interval (mph)
V = Midpoint speed of coast down interval (mph)
±3.3 = Allowable error in terms of force (pounds-force) equivalent
to ±0.25 HP
A, B, C = ' Dynamometer setting coefficients needed to set the
horsepower settings required in §85.2234(b) (1) (ii) and the
inertia weight selected (if electrically simulated). For this
calculation, these coefficients are those that represent
TRLHP minus CTRL, or IHP plus PLHP. The coefficients
used to adjust the dynamometer for coast-down test are
those needed to set the dynamometer for the IHP
corresponding to the horsepower settings required in
§85.2234(b)(l)(ii).
(iv) The clock used to check the coast-down time shall be accurate to the nearest
0.01 seconds when summing 1000 seconds.
(v) The results of each dynamometer coast-down check performed shall be
automatically computed and recorded on electronic media with a date and time
stamp.
(2) Roll Speed. Roll speed and roll counts shall be checked each operating day by an
independent means (e.g., photo tachometer). Deviations of greater than ±0.2 mph or a
comparable tolerance in roll counts shall require corrective action. Alternatively, a
redundant roll speed transducer independent of the primary transducer may be used in
lieu of the daily comparison. Accuracy of redundant systems shall be checked
monthly.
(3) Warm-Up. Dynamometers shall be in a wanned up condition for use in official testing.
Warm-up is defined as sufficient operation that allows the dynamometer to meet the
coast down time (within 3 seconds) identified for the specific dynamometer during
calibration. The reference coast-down time shall be the value for 55 to 45 mph with the
lightest inertia weight and lowest horsepower for that weight used during weekly
calibrations. Alternatively, the reference coast-down time shall be the value for 22 to 18
mph with the lightest inertia weight and lowest horsepower for that weight used during
weekly calibration, with a time standard of ±20%. warm-up may be checked by
comparing the measured parasitic losses at least 25 mph to reference values established
during calibration.
(4) Acceptance Testing. Upon initial installation and prior to beginning official testing, the
performance of each dynamometer and dynamometer design shall be verified for
IM240 Quality Control Page 32
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§85'2234 §85.2234
compliance with the requirements in §85.2226(a). Specific acceptance verification
requirements are described in paragraphs (b)(4)(i) through (b)(4)(v) of this section.
(0 Coast Down / Vehicle Loading Check. The coast down performance of each
dynamometer shall be checked with at least two categories of vehicles to verify
the ability of the dynamometer and dynamometer load setting system to meet
dynamometer target coast down times. The coast down performance of each
dynamometer design used shall be checked with at least 6 categories of vehicles
to determine the ability of the dynamometer design to properly load the vehicle
over the required speed range as defined in §85.2226 (a) (2). The performance
of the design shall be checked by the procedure defined in paragraphs
(b) (4) (i) (A) through (b) (4) (i) (L) of this section, or by a comparable procedure
acceptable to the Administrator.
(A) The dynamometer shall be warmed-up by the dynamometer
manufacturer's procedure, and the tires and drive train on the test
car shall be warmed-up by operating the vehicle at 50 mph for 20
minutes. The tire pressure in the test vehicles shall be at 45 psi.
(B) The dynamometer indicated power (fflP) and inertia weight for the
vehicle shall be selected for the test vehicle.
(C) The test vehicle shall be coasted down from 65 mph to 5 mph on
the dynamometer with the settings preselected in paragraph
(b) (4) (i) (B) in this section.
(D) The 55 mph to 45 mph, and the 22 mph to 18 mph coast down
times shall be recorded for the data collected in paragraph
(b) (4) (i) (C)of this section.
(E) The test vehicle shall again be coasted down from 65 mph to 5
mph on the dynamometer with the dynamometer power absorber
reset to a load of zero.
(F) A speed versus horsepower equation of the form in
§85.2226* (a) (2) (Ui) shall be determined for the data collected in
paragraph (b)(4)(i)(E) of this section.
(G) The test vehicle shall be removed from the dynamometer, and the
dynamometer shall be coasted down from 65 mph to 5 mph with
the dynamometer power absorber set to a load of zero.
(H) A speed versus horsepower equation of the form in
§85.2226(a)(2)(ix) for parasitic losses (PLHP) shall be
determined for the data collected in paragraph (b) (4) (i) (G) of this
section.
(I) The tire/roll interface losses shall be determined by subtracting the
horsepower curve determined in paragraph (b)(4)(i)(H) of this
section from the horsepower curve determined in paragraph
(b)(4)(i)(F) of this section. The tire loss curve (GTRL) shall be in
the form specified in §85.2226(a)(2)(xiii).
(J) Repeat the steps in paragraphs (b)(4)(i)(B) through (b) (4) (i) (I) of
this section to obtain a total of three sets of data for each test
vehicle. The dynamometer and vehicle may be warmed-up as
IM240 Quality Control Page 33
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585.2234 §85.2234
needed to meet the requirements in paragraph (b) (4) (i) (A) of this
section.
(K) For each test vehicle, compute the average 55 mph to 45 mph coast
down time, the average 22 mph to 18 mph coast down time, and
the average tire/roll interface loss curve as measured in paragraphs
(b)(4)(i)(B) through (b)(4)(i)(J) of this section.
(L) The dynamometer vehicle loading is considered acceptable if, for
each test vehicle, the average values determined in paragraph
(b)(4)(i)(K) of this section are within ±1 second of the 55 mph to
45 mph for the target time specified in §85.2226(a)(2)(ii), are
within ±7 percent of the 22 mph to 18 mph that is calculated from
§85.2226(a)(2)(iii) and §85.2226(a)(2)(iv), and within ±15
percent of a generic tire/roll loss curve for the category of vehicle.
(ii) Load Measuring Device Check. The load measuring device on each
dynamometer shall be checked by a dead-weight method (or equivalent) at least
six points across the range of loads used for vehicle testing. Physical checking
weights shall be traceable to NIST standards to within ± 0.5 percent
Equivalent methods shall document the method used to verify equivalent
accuracy. The accuracy of the interpreted value used for calculation or control
shall be within ±1 percent of full scale.
(iii) Vehicle Inertia Loading. The actual inertia applied to the vehicle by each inertia
weight in combination with the base inertia, shall be verified for each
dynamometer to insure compliance with the requirements in §85.2226(a)(4)(i)
or §85.2226(a)(4)(ii) as applicable.
(iv) Parasitic loss check between 8 and 12 mph. The coast down time of each
dynamometer between 8 and 12 mph shall be verified for compliance with the
requirements of §85.2226(a)(2)(x).
(v) Speed and Distance Check. The performance of the speed and distance
measuring system of each dynamometer shall be verified for compliance with
the requirements of §85.2226(a)(5)(i). The ability to resolve acceleration as
specified in §85.2226(a)(5)(i) need only be genetically verified for the design
used. If more than one design is used, each design shall be verified.
(vi) Warm-up System Check. The dynamometer warm-up system shall be checked
for compliance with the requirements in paragraph (b)(3) of this section by
conducting a coast down check immediately following completion of the warm-
up specified by the dynamometer manufacturer or the system. The design of
the warm-up system should be checked across the range of temperatures
experience in-use, and particularly at the lower speeds.
(5) Coast-down Times. Following acceptance, 55 to 45 mph, and 22 to 18 mph coast-down
times shall be determined for quality control purposes with the vehicle off the
dynamometer for each inertia weight and for at least 2 horsepower settings within the
normal range of the inertia weight These quality control values shall be determined
when the dynamometer has been set to meet either the coast-down target times with the
vehicle on the dynamometer (i.e., 55 to 45 mph and 22 to 18 mph), or the equation
coefficients.
(c) Constant Volume Sampler
1M240 Quality Control Page 34
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§85.2234 §852234
(1) Flow Calibration. The flow of the CVS shall be calibrated at six flow rates upon initial
installation, 6 months following installation, and every 12 months thereafter. The flow
rates shall include the nominal rated flow-rate and a rate below the rated flow-rate for
both critical flow Venturis and subsonic Venturis, and a flow-rate above the rated flow
for sub-sonic Venturis. The flow calibration points shall cover the range of variation in
flow that typically occurs when testing. A complete calibration shall be performed
following repairs to the CVS that could affect flow.
(2) System Check. CVS flow calibration at the nominal CVS design flow shall be checked
once per operating day using a procedure that identifies deviations in flow from the true
value. A procedure equivalent to that in §86.119(c) shall be used. Deviations greater
than ±4% shall result in automatic lockout of official testing until corrected.
(3) Cleaning Flow Passages. The sample probe shall be checked at least once per month
and cleaned if necessary to maintain proper sample flow. CVS venturi passages shall
be checked once per year and cleaned if necessary.
(4) Probe Flow. The indicator identifying the presence of proper probe flow for the system
design (e.g., proportional flow for CFV systems, minimum flow for time correlation of
different analyzers) shall be checked on a daily basis. Lack of proper flow shall require
corrective action.
(5) Leak Check. The vacuum portion of the sample system shall be checked for leaks on a
daily basis and each time the system integrity is violated (e.g., changing a filter).
(6) Bag Sample Check. On a quarterly basis, vehicle exhaust shall be collected in sample
bags with simultaneous integrated measurement of the sample. At least one bag each
for Phase 1 and for Phase 2 of the transient test cycle shall be conducted. Differences
between the two measurement systems greater than 10% shall result in system lockout
until corrective action is taken. For the purposes of acceptance testing, the differences
shall be no greater than 5%.
(7) Response Time Check. The response time of each analyzer shall be checked upon
initial installation, during each check for compliance with (c)(6) of this section, after
each repair or modification to the flow system that would reasonably be expected to
affect the response time, and at least once per week. The check shall include the
complete sample system from the sample probe to the analyzer. Statistical process
control shall be used to monitor compliance and establish fit for use limits based on the
requirements in §85.2226(c)(3). At a minimum, response time measurements that
deviate significantly from the average response time for all CVS systems designed to
the same specification in the program shall require corrective action before testing may
resume.
(8) Mixing Tee Acceptance Test
(i) The design of the mixing tee shall be evaluated by running the transient driving
cycle on at least two vehicles, representing the high and low ends of engine
displacement and inertia. Changes in the static tailpipe pressure with and
without CVS, measured on a second-by-second basis within 3 inches of the end
of the tailpipe, shall not exceed ±1.0 inch of water.
(ii) The ability of the mixing tee design to capture all of the exhaust as a vehicle
moves laterally from one extreme position on the dynamometer to the other
extreme shall be evaluated with back-to-back testing of three vehicles,
representing the high and low ends of engine displacement and inertia. The
back-to-back testing shall be done with the mixing tee at the tailpipe and with an
IM240 Quality Control Page 35
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§85-2234 §85.2234
airtight connection to the tailpipe (i.e., the mixing tee will be effectively moved
downstream, as in typical FTP testing). The difference in carbon-balance fuel
economy between the mixing tee located at the vehicle and the positive
connection shall be no greater than 5%.
(iii) The design of the dual exhaust system shall be evaluated with back-to-back
testing of three vehicles, representing the high and low ends of engine
displacement and inertia, with an airtight connection to the tailpipe (i.e., the
mixing tee will be effectively moved downstream, as in typical FTP testing, for
these qualification tests). The difference in carbon-balance fuel economy
between the two methods shall be no greater than 5%.
(d) Analysis System
(1) Calibration Curve Generation.
(0 Upon initial installation, calibration curves shall be generated for each analyzer.
If an analyzer has more than one measurement transducer, each transducer shall
be considered as a separate analyzer in the analysis system for the purposes of
curve generation and analysis system checks.
(ii) The calibration curve shall consider the entire range of the analyzer as one
curve.
(iii) At least 5 calibration points plus zero shall be used in die lower portion of the
analyzer range corresponding to an average concentration of approximately 2
gpm for HC, 30 gpm for CO, 3 gpm for NOx, and 400 gpm for C02- When
both a low range analyzer and a high range analyzer are used for a single
interest gas (e.g., CO), the high range analyzer shall use at least 5 calibration
points plus zero in the lower portion of the high range scale corresponding to
approximately 100% of the full-scale value of the low range analyzer. For all
analyzers, at least 5 calibration points shall be used to define the calibration
curve above the 5 lower calibration points. The calibration zero gas shall be
used to set the analyzer to zero.
(iv) Gas dividers may be used to obtain the intermediate points for the general range
classifications specified.
(v) The calibration curves generated shall be a polynomial of the best fit and no
greater than 4th order, and shall fit die data within 2.0% at each calibration point
as specified in §86.121-90, §86.122-78, §86.123-78, and §86.124-78. An
exception to the 2% fit may be allowed with approval by the Administrator if
supported by appropriate data for the lowest two non-zero calibration points,
provided that those points are below a value corresponding to an average
concentration of approximately 1 gpm for HC, 15 gpm for CO, 1.5 gpm for
NOx, and 200 gpm for C02. For those points the allowable curve fit may be
increased to no more than 5%. (For reference, see EPA NVFEL Procedure No.
204)
(vi) Each curve shall be verified for each analyzer with a confirming calibration
standard between 40-80% of full scale that is not used for curve generation.
Each confirming standard shall be measured by the curve within 2.5%.
(2) Spanning Frequency. The zero and up-scale span points shall be checked at 2 hour
intervals following the daily mid-scale curve check specified in paragraph (d)(4) of this
section and adjusted if necessary. If the up-scale span point drifts by more than 2.0%
IM240 Quality Control Page 36
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§85'2234 . §85.2234
from the previous check or, for the first check performed after the daily calibration
check described in paragraph (d)(4), from the daily check official testing shall be
prevented and corrective action shall be taken to bring the system into compliance. If
the zero point drifts by more than 2 ppmC HC, 1 ppm NOx, 10 ppm CO, or 40 ppm
C02, official testing shall be prevented and corrective action shall be taken to bring the
system into compliance. Or, the unit may be zeroed prior to each test.
(3) Limit Check. The tolerance on the adjustment of the up-scale span point shall be 0.4%
of point. A software algorithm to perform the zero and span adjustment and
subsequent calibration curve adjustment shall be used. Cumulative software up-scale
zero and span adjustments greater than ±10% from the latest calibration curve shall
cause official testing to be prevented and corrective action shall be taken to bring the
system into compliance.
(4) Daily Calibration Checks. The curve for each analyzer shall be checked and adjusted to
correctly read zero using a working zero gas, and an up-scale span gas within the
tolerance in paragraph (d)(3), and then by reading a mid-scale span gas within 2.5% of
point, on each operating day prior to vehicle testing. If the analyzer does not read the
mid-scale span point within 2.5% of point, the analyzer shall automatically be prevented
from official testing. The up-scale span gas concentration for each analyzer shall
correspond to approximately 80% of full scale, and the mid-point concentration shall
correspond to approximately 15% of full scale.
(5) Weekly NQx Converter Checks. The converter efficiency of the T 102 to NO converter
shall be checked on a weekly basis. The check shall be equivalent to §86.123-78 (for
reference see EOD Form 305-01) except that the concentration ov the NO gas shall be
in the range of 100-300 ppm. Alternative methods may be used if approved by the
Administrator.
(6) Weekly NO/NQx Flow Balance. The flow balance between the NO and NOx test
modes shall be checked weekly. The check may be combined with the NOx converter
check as illustrated in EPA NVFEL Form 305-01.
(7) Monthly Calibration Checks. The basic calibration curve shall be verified monthly by
the same procedure used to generate the curve in paragraph (d)(l) of this section, and to
the same tolerances.
(8) FID Check.
(i) Upon initial operation, and after maintenance to the detector, each FID shall be
checked, and adjusted if necessary, for proper peaking and characterization
using the procedures described in SAE Paper No. 770141 or by analyzer
manufacturer recommended procedures.
(ii) The response of each FID to a methane concentration of approximately 50 ppm
CH4 shall be checked once per month. If the response is outside of the range
of 1.0 to 1.30, corrective action shall be taken to bring the FID response within
this range. The response shall be computed by the equation in paragraph
..... _ . ... . _ FID response in ppmC
(m) Ratio of Methane Response = ppm C^ in cylinder
(9) Integrator Checks. Upon initial operation, and every three months thereafter, emissions
from a vehicle with transient cycle test values between 60% and 400% of the 1984
LDGV standard shall be simultaneously sampled by the normal integration method and
IM240 Quality Control Page 37
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§852234
by the bag method in each lane. The data from each method shall be put into a
historical data base for determining normal and deviant performance for each test lane,
facility, and all facilities combined. Specific deviations between the integrator and bag
readings exceeding ±10% shall require corrective action.
(10) Cross-Check^. On a quarterly basis, and whenever gas bottles are changed, each
analyzer in a given facility shall analyze a sample of a test gas. The test gas shall be
independent of the gas used for the daily calibration check in paragraph (d)(4), in
independent bottles. The same test gas, or gas mixture shall be used for all analyzers.
The concentration of the gas shall be one of three values corresponding to
approximately 0.5 to 3 times the outpoint (in gpm) for 1984 and later model year
vehicles for the constituent One of the three values shall be at the lower end of the
range, another shall be at the higher end of the range, and the other shall be near the
middle of the range. The values selected shall be rotated in a random manner for each
cross-check. The value of the checking sample may be determined by a gas divider.
The deviation in analysis from the concentration of the checking sample for each
analyzer shall be recorded and compared to the historical mean and standard deviation
for the analyzers at the facility and at all facilities. Any reading exceeding 3 sigma shall
cause the analyzer to be placed out of service.
(11) Interference - Laboratory Testing. The design of each CO, COz, and NOx analyzer
shall be checked for water vapor interference prior to initial service. The interference
limits in this paragraph shall apply to analyzers used with a CVS of 700 SCFM or
greater. For analyzers used with lower flow rate CVS units, the allowable interference
response shall be proportionately adjusted downward.
(i) CO Analyzer. A gas mixture of 4% CC<2 in N£ bubbled through water with a
saturated-mixture temperature of 40°C shall produce a response on the CO
analyzer of no greater than 15 ppm at 40°C. Also, a gas mixture of 4 percent
CO2 in Na shall produce a response on the CO analyzer of no greater than 10
ppm at 40°C.
(ii) CQ2 Analyzer. A calibration zero gas bubbled through water with a saturated-
mixture temperature of 40°C shall produce a response on the COa analyzer of
no greater than 60 ppm.
(iii) NOx Analyzer. A calibration zero gas bubbled through water with a saturated-
mixture temperature of 40°C shall produce a response on the NOx analyzer of
no greater than 1 ppm. Also, a gas mixture of 4 percent C02 in either N2 or air
shall produce a response on the NOx analyzer of no greater than 1.0 ppm at
40°C.
(12) Interference - Field Testing. Each CO, COa, and NOx analyzers shall be checked for
water vapor interference prior to initial service, and on a yearly basis thereafter. The in-
field check prior to initial service and the yearly checks shall be performed on a high
ambient temperature summer day (or simulated conditions). For analyzers used with
lower flow rate CVS units, the allowable interference response shall be proportionately
adjusted downward. The allowable interference level shall be adjusted to coincide with
the saturated-mixture temperature used. For the CO analyzer, a rejection ratio of 9,000
to 1 shall be used for this calculation. A ratio of 2000 to 1 shall be used for COz
analyzers. A ratio of 90,000 to 1 shall be used for NOx analyzers.
(e) Gases
(1) General Requirements. FID gas shall be propane. Multi-component gases may be
used after approval by the Administrator.
1M240 Quality Control Page 38
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§85.2234 §852234
(2) Calibration Gases. Gases used to generate and check calibration curves shall be
traceable to a NIST SRM, CRM, NTRM, or ROM and have a stated uncertainty to
within 1% of the standard by Gas Comparison methods. Calibration zero gas shall be
used when using a gas divider to generate intermediary calibration gases.
(3) Span Gases. Gases used for up-scale span adjustment, cross-checks, and for mid-scale
span checks shall be traceable to NIST SRM, CRM, NTRM, or ROM and have a stated
uncertainty to within 2% of the standard by Gas Comparison methods. Span gas
concentrations shall be verified immediately after a monthly calibration curve check and
before being put into service. If the reading on the span gases exceeds 2% of the label
value, the system or gases shall be taken out of service until corrective action is taken.
When a gas divider is used to generate span gases, the diluent gas shall not have
impurities any greater than the working zero gas.
(4) Calibration Zero Gas. The impurities in the calibration zero gas shall not exceed 0.1
ppmC, 0.5 ppm CO, 1 ppm CO2, and 0.1 ppm NO. Calibration zero grade air shall be
used for the FID zero calibration gas. Calibration zero grade nitrogen or calibration
zero grade air shall be used for CO, C02, and NOx zero calibration gases.
(5) Working Zero Gas. The impurities in working zero grade gases shall not exceed 1
ppmC, 2 ppm CO, 400 ppm C02, and 0.3 ppm NOx. Working zero grade air or
calibration zero grade air shall be used for die FID zero span gas. Working or
calibration zero grade nitrogen or air shall be used for CO, C02, and NOx zero span
gases.
(6) FID Fuel. The fuel for the FID shall consist of a mixture of 40% (±2%) hydrogen,
and the balance helium. The FID oxidizer shall be zero grade air, which can consist of
artificial air containing 18 to 21 mole percent of oxygen.
(7) Gas Naming Protocol. (Reserved)
(f) Overall System Performance
(1) Emission Levels. For each test lane, the average, median, 10* percentile and 90*h
percentile of the composite emissions (HC, CO, C02. and NOx) measured shall be
monitored on a monthly basis. Differences in the monthly average of greater than
±10% by any one lane from the facility-average or combined facility-average, or by any
one facility from the combined facility-average shall require an investigation to
determine whether the single lane or facility has a systematic equipment or operating
error or difference. Where it can be determined that the averages from one facility (or
facilities) are offset from the average of the other facilities based on the mix of vehicles
tested, the ±10% limit shall be compared to the expected offset If systematic
equipment or operating errors or differences causing the offset are found, such errors
shall be corrected. The sample period may be adjusted to assure that a reasonably
random sample of vehicles was tested in each lane.
(2) Pass/Fail Status. The average number of passing vehicles and the average number of
failing vehicles shall be monitored monthly for each test lane. Differences in the
monthly average of greater than ±15% by any one lane from the facility-average or
combined facility-average, or by any one facility from the combined facility-average
shall require an investigation to determine whether the single lane or facility has a
systematic equipment or operating error or difference. Where it can be determined that
the averages from one facility (or facilities) are offset from the average of the other
facilities based on the mix of vehicles tested, the ±15% limit shall be compared to the
expected offset If systematic equipment or operating errors or differences causing the
IM240 Quality Control Page 39
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§85.2234 §85.2234
offset are found, such errors shall be corrected. The sample period may be adjusted to
assure that a reasonably random sample of vehicles was tested in each lane.
(g) Control Charts
(1) General Requirements. Control charts and Statistical Process Control theory shall be
used to determine, forecast, and maintain performance of each test lane, each facility,
and all facilities in a given network. The control charts shall cover the performance of
key parameters in the test system. When key parameters approach control chart limits,
close monitoring of such systems shall be initiated and corrective actions shall be taken
when needed to prevent such systems from exceeding control chart limits. If any key
parameter exceeds the control chart limits, corrective action shall be taken to bring the
system into compliance. The control chart limits specified are those values listed for the
test procedures, the equipment specifications, and the quality control specifications that
cause a test to be voided or require equipment to be removed from service. These
values are "fit for use" limits, unlike a strict interpretation of SPC control chart theory
which may use tighter limits to define the process. The test facility is encouraged to
apply SPC strict control chart theory to determine when equipment or processes could
be improved. No action shall be required until the equipment or process exceeds the
"fit for use limits" specified in this section.
(2) Control Charts for Individual Test Lanes. In general, control charts for individual test
lanes shall include parameters that will allow the cause for abnormal performance of a
test lane to be pinpointed to individual systems or components. Test lane control charts
shall include at a minimum:
(i) Overall number of voided tests
(ii) Number of voided tests by type
(iii) Level of difference between theoretical and measured coast-down times
(iv) Level of difference between theoretical and measured CVS flow
(v) Level of up-scale span change from last up-scale span (not required if software
corrections are tracked)
(vi) Level of mathematical or software correction to the calibration curve as a result
of an up-scale span change (if used)
(vii) Level of difference between the analyzer response to the daily cross-check, and
the test gas concentration
(viii) Level of difference between the integrated measurements and the bag
measurements
(ix) The system response time
(x) Level of the FED CH4 response ratio
(xi) Level of the ambient background concentrations
(xii) The average, median, 10th percentile and 90th percentile of the composite
emissions (HC, CO, COz, and NOx) measured over the defined periodic basis
IM240 Quality Control Page 40
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§85.2234 §85.2234
(xiii) Average number of passing vehicles, and average number of failing vehicles
over the defined periodic basis
(xiv) Level of difference between theoretical or measured values for other parameters
measured during quality assurance procedures
(3) Control Charts for Individual Facilities. Control charts for individual facilities shall
consist of facility-averages of the test lane control charts for each test lane at the facility.
(4) Combined Control Charts for All Facilities. Combined control charts for all of the
facilities in a given network shall consist of an average of the facility-average control
charts for each facility.
(5) Control Charts of Individual Inspectors. Control charts for individual inspectors shall
include parameters that will allow the cause for abnormal performance to be evaluated.
Control charts for individual inspectors shall be compared to the combined control
charts for each facility and for the network.
IM240 Quality Control Pa8e 41
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§85.2235 §85.2235
§85.2235 Evaporative Test System Quality Control Requirements
(a) Evaporative Purge Analysis System Flow Checks
(\) Daily Check. Each flow meter used to measure purge flow shall be checked each
operating day with simulated purge flow (e.g., auxiliary pneumatic pump) against a
reference flow measuring device with performance specifications equal to or better than
those specified for the purge meter. The check shall be made at a flow rate of between
4 and 5 liters per minute. The test shall be conducted for one minute. Deviations
greater than ±0.3 liters per minute, or ±3% of total flow from the values determined by
the reference device shall require corrective action.
(2) Monthly Check. On a monthly basis, the calibration of purge meters shall be checked
for total volume of flow at 0.8,2,20, and 35 liters over 4 minutes with a device or
method capable of measuring these flow volumes to within ±0.2 liters over the test
period. Deviations exceeding 1.5 times the specifications in §85.2227(a)(2)(v)(D) shall
require corrective action.
(b) Evaporative Pressure System Check
(1) Daily Check. Relevant parameters of the evaporative system integrity analysis system
shall be checked on each operating day. At a minimum, systems that monitor pressure
leak down shall be checked for integrity. If, after the canister end of the checking
system is capped and the checking system is pressurized to between 14 and 28 inches
of water, the pressure system changes more than 0.2 inches of water over 15 seconds,
official testing shall be automatically prevented until corrective action is taken.
(2) Weekly Check. Pressure gauges or measurement devices shall be checked on a weekly
basis against a reference gauge or device equal to or better than the specified
performance requirements. Deviations exceeding the specified accuracy shall require
corrective action.
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§85'2239 §85.2239
§85.2239 Test Report - IM240 and Evaporative Tests
(a) General Test Report Information
(1) Vehicle Description.
(i) License plate number,
(ii) Vehicle identification number,
(iii) Weight class, and
(iv) Odometer reading.
(2) Date and end time of the tailpipe emission measurement test
(3) Name or identification number of the individual performing the test and the location of
the test station and lane.
(4) For failed vehicles, a statement indicating the availability of warranty coverage as
provided in Section 207 of the Clean Air Act
(5) A statement certifying that the short tests were performed in accordance with applicable
regulations.
(b) Tests and Results
(1) Test Types and Standards. The test report shall indicate the types of tests performed on
the vehicle and the test standards for each. Test standards shall be displayed to the
appropriate number of significant digits as in §85.2205. For the IM240 the reported
standards shall be the composite test standards.
(2) Test Scores. The test report shall show the scores for each test performed. Test scores
shall be displayed to the same number of significant digits as the standards.
(3) IM24Q Scores. The reported score for the EM240 shall be in units of grams per mile
and shall be selected based upon the following:
(i) If the emissions of any exhaust component on the composite IM240 are below
the applicable standard in §85.2205(a)(2) through §85.2205(a)(4). then the
vehicle shall pass for that constituent and the composite score shall be reported.
(ii) If the emissions of any exhaust component on the composite IM240 exceed the
applicable standard in §85.2205(a) (2) through §85.2205(a) (4) but are below the
Phase 2 standard, then the vehicle shall pass for that component and the Phase 2
score shall be reported.
(iii) If the emissions of any exhaust component on the composite IM240 exceed the
applicable standard in §85.2205(a)(l) through §85.2205(a)(4) and exceed the
Two Ways to Pass Standard as described in §85.2205(a)(5), then the vehicle
shall fail for that component and the composite score shall be reported.
(iv) If a pass or fail decision is made for all three exhaust components on the
IM240, and for purge before the end of the full driving cycle according to the
criteria described in paragraphs §85.2205(a)(4) and §85.2205(c)(3), the
pass/fail results and reported emissions levels shall be those'obtained at the time
the test is terminated.
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§85.2239 §85.2239
(4) Purge Scores. The reported score for the purge test shall be reported in units of liters
and shall be selected based upon the following:
(i) If purge levels at the conclusion of the transient driving cycle are below the
applicable standard in §85.2205(c) (2), then the vehicle shall fail.
(ii) If a pass or fail decision is made for all three exhaust components on the
IM240, and for purge before the end of the full driving cycle according to the
criteria described in paragraphs §85.2205(a)(4) and §85.2205(c)(3), the
pass/fail result and reported cumulative purge levels shall be those obtained at
the time the test is terminated.
(5) Test Results. The test report shall indicate the pass/fail result for each test performed
and the overall result In the case of exhaust emission tests, the report shall indicate the
pass/fail status for each component for which standards apply.
(6) Second-by-Second Measurements. For vehicles failing the IM240, a table or graph
showing the second-by-second emission levels, for each exhaust component in grams
per second, and for purge in liters per second shall be made available to the motorist or
repair technician. This may be accomplished either by including it in the test report, or
by making it available directly to any repair provider through electronic means within a
reasonable interval after completion of die test
Test Report Page 44
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§85.2231
§85.2231
§85.2231 Terms
(a) Definitions
(1) Track coast-down target time: The new vehicle certification track coast-down time
between 55 and 45 mph.
(2) Road load horsepower The power required for a vehicle to maintain a given constant
speed taking into account power losses due to such things as wind
resistance, tire losses, bearing friction, etc.
New gaseous and paniculate tailpipe emission standards for use in
certifying new light duty vehicles and light duty trucks phased in beginning
with the 1994 model year.
CVS hose: The hose, connecting to the tailpipe of the vehicle, that carries exhaust and
dilution air to the stationary portion of the CVS system.
(3) Tier 1:
(4)
(b) Abbreviations
(1) CFV:
(2) CH*
(3) C02:
(4) CO:
(5) CRM:
(6) CVS:
(7) FID:
(8) gpm:
(9) GVWR:
(10) HC:
(11) HDGT:
(12) hp:
(13) Hz:
(14) I/M:
(15) IW:
(16) LDGT1:
(17) LDGT2:
(18) LDGV:
(19) LVW
(20) mph:
(21) NDIR:
(22) MIST:
(23) NO*
(24) NO:
(25) NOx:
(26) NVFEL:
(27) Obmph:
(28) PLHP:
(29) ppm:
(30) ppmC:
(31) psi:
(32) RFP:
(33) RLHP
(34) rpm:
(35) SCFM:
Critical flow venturi
Methane
Carbon dioxide
Carbon monoxide
Certified reference material
constant volume sampler
Flame ionization detector
Grams per mile
Gross Vehicle Weight Rating
Hydrocarbons
Heavy-Duty Gasoline-powered Truck greater than 8500 pounds GVWR
horsepower
cycles per second (Hertz)
Inspection and Maintenance
Inertia weight
Light-Duty Gasoline-powered Truck from 0 to 6000 pounds GVWR
Light-Duty Gasoline-powered Truck from 6001 to 8500 pounds GVWR
Light-Duty Gasoline-powered Vehicle
Loaded Vehicle Weight
Miles per hour
non-dispersive infrared
National Institute for Standards and Technology
Nitrogen dioxide
Nitrogen oxide
Oxides of nitrogen
National Vehicle and Fuel Emissions Laboratory
Observed dynamometer speed in mph of the loading roller, if rolls are not
coupled
Parasitic horsepower loss at the observed dynamometer speed in mph
parts per million by volume
parts per million, carbon
Pounds per square inch
Request for Proposal
Road Load Horsepower
revolutions per minute
standard cubic feet per minute
Terms and Abbreviations
Page 45
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§85.2231 §85.2231
(36) SPC: Statistical process control
(37) SRM: Standard reference material
(38) SSV: Subsonic venturi
(39) TRLHP: Track road-load horsepower
Terms and Abbreviations ?age #>
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