United States
Environmental Protection Agency
May 1993
Air
High-Tech I/M Test Procedures,
Emission Standards, Quality Control
Requirements, and Equipment
Specifications
Technical Guidance
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Table of Contents
Page
Table of Contents i
Introduction 1
§85.2205 Short Test Standards - IM240-Purge Test 2
(a) IM240 Emission Standards 2
(b) Transient Test Score Calculations 4
(c) Purge Test Standards 7
§85.2221 EM240-Purge Test Procedure 8
(a) General Requirements 8
(b) Pre-inspection and Preparation 8
(c) Equipment Positioning and Settings 9
(d) Vehicle Conditioning 10
(e) Vehicle Emission Test Sequence 11
(f) Emission Measurements 14
§85.2226 IM240 Equipment Specifications 15
(a) Dynamometer Specifications 15
(b) Constant Volume Sampler 19
(c) Analytical Instruments 21
§ 8 5.2227 Evaporative S ystem Inspection Equipment 24
(a) Evaporative Purge System 24
(b) Evaporative System Integrity Analysis System 25
§ 8 5.2234 LM240 Test Quality Control Requirements 26
(a) General Requirements 26
(b) Dynamometer 26
(c) Constant Volume Sampler 29
(d) Analysis System 30
(e) Gases 32
(0 Overall System Performance 33
(g) Control Charts 34
§85.2235 Evaporative Test System Quality Control Requirements 36
(a) Evaporative Purge Analysis System Flow Checks 36
(b) Evaporative Pressure System Check 36
§85.2239 Test Report - IM240 and Evaporative Tests 37
(a) General Test Report Information 37
(b) Tests and Results 37
§85.2231 Terms 39
(a) Definitions 39
(b) Abbreviations 39
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Introduction
This document is the successor to EPA's "High-Tech Tests: Draft Guidance on Developing an
RFP " It is the result of a cooperative effort among EPA. the automobile manufacturers, die I/M
equipment manufacturers and contractors, and states to resolve outstanding technical issues and
finalize EPA's guidance to state I/M programs on I/M test procedures and related requirements.
In the process of promulgating the I/M regulation, published on November 5,1992. EPA
received numerous comments on a variety of technical issues regarding test procedures. Primarily the
comments reflected a desire to be certain that sufficient safeguards would be in place to prevent false
failures, as well as a desire to see enough flexibility in the equipment specifications and quality control
requirements to allow for innovative technical approaches to reduce overall costs. Since the
comments came from a variety of parties with different technical perspectives and different interests,
EPA convened a technical committee composed of representatives from EPA, the automobile
manufacturers, the I/M equipment manufacturers and contractors, and the states. Every provision
detailed in this document was discussed extensively in the committee with input from all sides. While
some of die details have changed from die earlier document, there is general agreement that cost and
test time have not been substantially changed from previous estimates.
The test procedures and related requirements are presented in diis document in die language
and format in which EPA intends to propose to promulgate them in die 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 October of this year. However, EPA recognizes the need to publish detailed
technical guidelines now so that states may use them in developing their I/M SIPs, due on November
15 of this year. The provisions in this document have not yet been proposed as regulations and
interested panics will still have die opportunity to comment on diem when they are. However. EPA
believes that given diat die test procedures and related requirements, as presented here, reflect a
general agreement among die primary interested parties, and that minimal changes, if any, will be
made in the rulemaking process.
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§85 2205 §85 2203
§85.2205 Short Test Standards - IM240-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 pollutant, 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 and composite
emission rates for Phase 2 and for the entire test shall be recorded in grams per mile
for each gas. For any given pollutant, if die composite emission level is below the
composite standard or if the Phase 2 grams per mile emission level is below the
applicable Phase 2 standard, then the vehicle shall pass the test for that pollutant.
(2) Phase-in Standards. Phase-in standards should be used during calendar years 1995
and 1996. Exhaust emissions standards for 1981 and newer vehicles no tighter than
the following are recommended.
(i) 1990 and Newer Light-Duty Vehicles. Short test emission standards on the
composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.20 gpm 0.75 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 3.0 gpm (Reserved)
(ii) 1981 to 1989 Light-Duty Vehicles. Short test emission standards on the
composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 2.00 gpm 1.25 gpm
(B) Carbon Monoxide: 30.0 gpm 24.0 gpm
(C) Oxides of Nitrogen: 3.5 gpm (Reserved)
(iii) 1990 and Newer Light-Duty Trucks. Short test emission standards on the
composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.20 gpm 0.75 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 3.5 gpm (Reserved)
(iv) 1981 to 1989 Light-Duty Trucks. Short test emission standards on the
composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 2.00 gpm 1.25 gpm
(B) Carbon Monoxide: 30.0 gpm 24.0 gpm
(C) Oxides of Nitrogen: 4.0 gpm (Reset ved)
(3) Final Standards. The following exhaust emissions standards shall apply to 1981 to
1995 model year vehicles tested in the calendar years 1997 and later except as
provided in paragraph (a)(3). The following standards will be subject to review by
the Administrator prior to implementation and may be revised if necessary.
Standards I Calculations Page 2
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§85 2205 §85 2205
U) 1981 and Newer pre-Tierl Light-Duty Vehicles. Short test emission
standards on the composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 0.80 gpm 0.50 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 2.0 gpm (Reserved)
(li) 1981 to 1983 Light-Duty Trucks. Short test emission standards on the
composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 3.50 gpm 2.20 gpm
(B) Carbon Monoxide: 35.0 gpm 28.0 gpm
(C) Oxides of Nitrogen: 4.5 gpm (Reserved)
(iii) 1984 to 1987 Light-Duty Trucks. Short test emission standards on the
composite 1M240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.60 gpm 1.00 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 4 5 gpm (Reserved)
(iv) 1988 to 1990 Light Duty Trucks 1. Short test emission standards on the
composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.60 gpm 1.00 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 3.0 gpm (Reserved)
(iv) 1988 to 1990 Light Duty Trucks 2. Short test emission standards on the
composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.60 gpm 1.00 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 4.5 gpm (Reserved)
(v) 1990 and Newer Pre-Tier 1 Light Duty Trucks. Short test emission
standards on the composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 1.60 gpm 1.00 gpm
(B) Carbon Monoxide: 25.0 gpm 20.0 gpm
(C) Oxides of Nitrogen: 3.0 gpm (Reserved)
(4) Final Standards for Tier 1 Vehicles. The following exhaust emission standards shall
apply to 1996 and later vehicles and may be applied to 1994 and 1995 vehicles
certified to Tier 1 emission standards. The following standards will be subject to
review by the Administrator prior to implementation and may be revised if
necessary.
(i) Tier 1 Light-Duty Vehicles. Short test emission standards on the composite
IM240 test shall not be less than:
Standards I Calculations Page 3
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583.2205 §85 2205
Composite Phase 2
(A) Hydrocarbons: 0.70 gpm 0.44 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 1.4 gpm (Reserved)
(ii) Tier 1 Light Light-Duty Trucks i. Short test emission for trucks less than or
equal to 6000 pounds GVWR and and less than or equal to 3750 pounds
LVW standards on the composite EM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 0.75 gpm 0.44 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 2.5 gpm (Reserved)
(iii) Tier 1 Heavy Light-Duty Trucks 2. Short test emission for trucks less than
or equal to 6000 pounds GVWR and greater than 3750 pounds LVW
standards on the composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 0.75 gpm 0.47 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 2.5 gpm (Reserved)
(iv) Tier 1 Light Light-Duty Trucks 2. Short test emission for trucks greater than
6000 pounds GVWR and and less than or equal to 5750 pounds LVW
standards on the composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 0.75 gpm 0.44 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 2.0 gpm (Reserved)
(v) Tier 1 Heavy Light-Duty Trucks 2. Short test emission for trucks greater
than 6000 pounds GVWR and greater than 5750 pounds LVW standards on
the composite IM240 test shall not be less than:
Composite Phase 2
(A) Hydrocarbons: 0.80 gpm 0.50 gpm
(B) Carbon Monoxide: 15.0 gpm 12.0 gpm
(C) Oxides of Nitrogen: 2.5 gpm (Reserved)
(5) Fast-Pass. (Reserved).
(6) Fast-Fail. (Reserved).
(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 pollutant obtained in each
second of the test or mode by the number of miles driven in the test or test mode.
The IM240 shall be divided into four modes as follows:
Mode Cycle Portion
1 0-60 seconds
2 61-119 seconds
3 120-174 seconds
Standards I Calculations Page 4
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$85 2205
§85 2205
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)( 1 )(i):
(i)
Composite gpm
Where:
s =
£ grams of emissions
sec=0
s
£ miles traveled
sec=0
duration of test in seconds for fast pass / fast fail
239 seconds for complete IM240
(ii) Where the composite emissions are to be calculated by weighting factors, the
equation in (b)(l)(iii) shall be used
WF1
f si
^ gramse
sec=0
si
£ miles
L sec=0
WF2
WF3*
gramse
sec=s2+l
s3
£ miles
- sec=s2+l
WF4*
r s2
X gramse
sec=sl+l
s2
£ miles
L sec=sl+l
f s4
X gfamse
sec=s3+l
s4
X miles
- sec=s3+l
Where: gramse =
miles =
si
s2
s3
s4
WFl =
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)
(2) Second-bv-Second Mass Calculations. The mass of each pollutant shall be
calculated for each second of the test using the following equations:
(i) Hydrocarbon mass: HCmass = VmK*DensityHC*(HCCOnc/l.000.000)
(ii) Carbon Monoxide mass: C0mass = Vmix*Densityco"(COCOnc/l.000.000)
(iii) Oxides of Nitrogen mass:
NOxmass = Vmix*DensityNO2*KH*(NOXconc/l, 000,000)
(iv) Carbon Dioxide mass: CO2niass = Vmjx*Densityco2*(CO2Conc/100)
Standards I Calculations
PageS
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§85.2205 §85 2205
(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 hydrocarbon ratio of 1:1.85 at 68°F and 760
mm Hg pressure.
(ill) HQonc = 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-HCd(l-l/DF). Where:
(B) HCe = Hydrocarbon concentration of the dilute exhaust
sample as measured in ppm carbon equivalent.
(C) Background hydrocarbon concentration of the dilution air,
sampled as described in §85.2221(b)(5), as measured in
ppm carbon equivalent.
(D) DF = 1 3.4 / [CO2e+(HCe+COe)*10-*], calculated on a
second-by-second basis.
= The CVS flow rate in cubic feet per second corrected to standard
temperature and pressure.
(v) COmass = Carbon monoxide emissions in grams per second.
(vi) Densiryco = 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 CC>2 extraction, in ppm.
(A) COconc = COe-COdd-1/DF)
(B) COe = Carbon monoxide concentration of the dilute exhaust
volume corrected for water and carbon dioxide extraction in
ppm.
(C) C0e = (l-0.01925C02e-0.000323R)COem
(D) COem = Background carbon monoxide concentration of the
dilution air, sampled as described in §85.2221(b)(5), as
measured in ppm.
(E) CO2e = Carbon dioxide concentration of the dilute exhaust
sample in percent.
(F) R = Relative humidity of the dilution air in percent.
(viii) NOxmass = Oxides of nitrogen emissions in grams per second.
(ix) DensityNO2 = 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 = NOxe-NOxdd-1/DF)
(B) NOxe = Oxides of nitrogen concentration of the dilute exhaust
sample as measure in ppm.
Standards I Calculations Page 6
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§85 2205 §85 2205
(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=Huirudity 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)R.*Pd]/[PB-(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
(F) PB = Barometric pressure, mm Hg.
(xii) CChmass = Carbon dioxide emissions in grams per second.
(xiii) Densitycoi = Density of carbon dioxide is 51.81 grams per cubic foot at
68»F and 760 mm Hg.
(xiv) CO2conc = 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) C02c0nc = C02e-C02d(l-l/DF)
(B) C02d = Background carbon dioxide concentration of the
dilution air. sampled as described in §85.2221(b)(5), as
measured in percent.
(c) Purge Test Standards
(I) 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 l.U 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) Flow Rate Method. (Reserved)
Standards I Calculations Page 7
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§85.2221 §852221
§85.2221 IM240-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, LDGT 1 . 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) l^eaks. 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
pollutant. Vehicles in overheated condition shall be rejected from testing.
(4) Tire Condition. Vehicles shall be rejected from testing if the tire cords are visible.
Vehicles shall be rejected that have space-saver spare tires on the drive axle. 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 CO2,
respectively) shall be sampled as specified in §85.2226(b)(2)(ii)(4) 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 (f)(3) of this section. Average readings over the 15
seconds for each gas shall be recorded in the test record. Testing shall be prevented
Test Procedures Page 8
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§852221 §85.2221
until the average ambient background levels are less than 20 ppmC HC, 30 ppm CO,
and 2 ppm NOx or outside ambient air levels, whichever are greater.
(6) Sample System Puree. While a lane is in operation, the CVS shall continuously
purge the CVS hose between tests, and die sample system shall be continuously
purged when not taking measurements.
(7) Negative Values. 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 purge
test and purge flow measurement shall not be taken.
(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 test. All hoses shall be reconnected after a purge flow
test is performed.
(lii) 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
positioned and activated. The cooling system shall be positioned to direct air to the
vehicle cooling system, but shall not be directed at the catalytic convener.
(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).
(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 9
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§85.2221
§83 2221
;
VEHICLE
TYPE
All
All
' All
' All
LDGV
LDGT
LDGV
LDGT
; LDGV
' LDGT
• i
; NUMBEROF <
CYLINDERS i
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
112
12.7
12.0
134
i TEST
• INERTIA
i WEEGHT
" 2000
' 2500
i 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 fails the initial test and all criteria pollutants 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 die
dynamometer, drive a transient cycle consisting of speed, time, acceleration.
and load relationships similar to that of the transient driving cycle in (e)( 1) 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 10
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§85 2221
§83 2221
(e) Vehicle Emission Test Sequence
(1) Transient Driving Cycle. The vehicle shall be driven over the following cycle:
Tune i Speed 5 Time : Speed I Time i Speed
second i mph i second i mph i second i mph
6* 0 48 25 7 I 96 (')
! 1 0 49 26.1 97 0
I 0
50 26 7 98 3 3
3 0 51275 99 6 6
4 0 52 28 6
5 3 53 29 1
6 5.9
7 86
8 115
9 14 3
10 16.9
11 17 3
12 18 1
13 207
14 21 7
54 298
55 30 1
56 30.4
57 307
58 30.7
59 30.5
60 30.4
61 30 3
62 30.4
15 224 i 63 30.8
16 22.5
17 22.1
18 21.5
19 209
20 20.4
21 198
22 17
23 149
24 14.9
25 15 2
26 15 5
27 16
28 17 1
29 19.1
30 21.1
31 22.7
32 22.9
33 22.7
34 22.6
35 21.3
36 19
37 17.1
38 15.8
39 15.8
40 17 7
41 14 8
42 21 6
43 23 2
44 24.2
. 43 24.6
46 249
64 30 4
65 29 9
66 29.5
67 29 8
68 30.3
69 30.7
70 309
71 31
72 30.9
73 30.4
74 29.8
75 299
76 30.2
77 30.7
78 U 2
79 31.8
80 32.2
81 32.4
82 32.2
83 31.7
84 28.6
85 25.1
86 21.6
87 18.1
88 146
89 11.1
90 76
91 4 1
92 06
93 0
94 0
47 25 95 0
1(10 99
101 132
102 165
103 19.8
104 22.2
105 24.3
106 25.8
107 26.4
108 25.7
109 25.1
110 247
111 25.2
112 254
113 272
114 26.5
115 24
116 22.7
117 194
118 17.7
119 172
120 18 1
121 18.6
122 20
123 207
124 21.7
125 22.4
126 22.5
127 22.1
128 21.5
129 20.9
130 20.4
131 19.8
132 17
133 17 1
134 15.8
135 138
136 17.7
137 19.8
138 21.6
139 22.2
140 24 5
141 24.7
142 24.8
143 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
256
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
479
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 : Speed
second ' mph
192 546
193 54 8
194 55 1
195 55 5
196 557
197 56 1
198 56.3
199 566
200 56 7
201 56.7
202 56 3
203 56
204 55
205 53 4
206 51.6
207 51.8
208 52 1
209 52.5
210 53
211 535
212 54
213 54.9
214 554
215 55 6
216 56
217 56
218 55.8
219 55 2
220 54 5
221 53 6
222 52.5
223 515
224 50 5
225 48
226 44 5
227 41
228 37 5
229 34
230 30.5
231 27
232 23.5
233 20
234 16 5
235 13
236 9.5
237 6
238 2 5
239 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 (e)(3).
Test Procedures
Page 11
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§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
M-2
2-3
13-2
J2-3
3-4
4-5
15-6
j De-clutch
Speed
miles per hour
15
25
15
15
25
-17.2
25
40
45
50
15
Approximate
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 except for the shift at second 119.0, which shall occur at the specified
time.
(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 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 = The slope of the regression line;
(C) x = The reference value; and
(D) b = The y-intercept of the regression line.
Test Procedures
Page 12
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§852221 §85.2221
(n) The standard error of estimate (SE) of y on x shall be calculated for each
regression line. A transient driving cycle that exceeds the following criteria
shall be void and the test shall be repeated:
(A) SE = 2.0 mph maximum;
(B) m = 0.96- 101;
(C) r2 = 0.97 minimum:
(D) b = ±2.0 mph.
(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.
(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 lip, 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 throughout the test by
monitoring the difference in pressure from atmosphere for a CFV-type CVS or the
difference in pressure between upstream and throat pressure on a SSV-type CVS.
The minimum values shall be determined from system calibrations. Monitored
pressure differences below the minimum values shall void the test.
(6) 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 for the test inertia and horsepower selected. For each inert la
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 judgement. 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.
Test Procedures Page 13
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§852221 §85.2221
(f) Emission Measurements
(1) Exhaust Measurement. The emission analysis system shall sample and record dilute
exhaust HC. CO, CO2, and NO* during the transient dnving cycle as described in
§85.2226(c)(4).
(2) Puree Measurement. The analysis system shall sample and record the purge flow in
standaid liters per second and total volume of flow in standard liters over the course
of the actual dnving 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 Page 14
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§85 2226 §85 2226
§85.2226 IM240 Equipment Specifications
(a) Dynamometer Specifications
(1) General Requirements.
(0 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, Bv, and Cv, 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@ 50 mph) hp/mph
(B) Bv = (0.10/2500)*(TRLHP@50mph)hp/mph2
(C) Cv = (0.55/l25,000)*(TRLHP@50mph)hp/mph3
(ii) Vehicle Loading. The true veliicle 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) TRLHP@ Obmph= {Av * Obmph) + {Bv * Obmph2} + {Cv * Obmph3)
AV,BV Cv = Coefficients specified in paragraph (a)(2)(i) of 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 15
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§85 2226 §85 2226
5 * FTW\
C1
_ v x
32.2 1 ' V2 )
(iv) Track Road-Load Horsepower = ^ - (550 * 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
V. = 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 18
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 (Bv in HP/mph2 units)
Cf = 375 *CV (Cv in HP/mph3 units)
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 4 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 4 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)(bO to within 2 percent of point.
Equipment Page 16
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§85 2226 §85 2226
(ix) PLHP = (Ap * (Obmph) | + ((Bp) * (Obmph)2) + {(Cp) * (Obmph)3)
PLHP = Dynamometer parasitic losses.
Ap, Bp, and Cp are curve coefficients necessary to properly
characterize the dynamometer parasitic losses for the inertia
weights) used.
(x) Parasitic Losses (Low Speed Requirements). The coast down time of the
dynamometer between 8 and 12 mph shall not exceed 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 4 horsepower at 50
mph.
(xi) ET =
ETW * (V[22 - Vg2)
21.94 * (Af4 + Bf4V + Cf4V2)
Vjj = 12 mph
Vg =8 mph
V = 10 mph
Af4 = 375 * A(]4 (A^ in HP/mph units)
Bf4 = 375 * Bd4 (844 in HP/mph2 units)
Cf4 = 375 * C(|4 (Cj4 in HP/mph3 units)
Af4( Bf4 and Cf4 are dynamometer road-load curve
coefficients in "force" units which include parasitic losses
and power absorber loading.
« Bd4. and Ql4 are the dynamometer road-load curve
coefficients necessary to properly load a vehicle with a 50
mph track road-load horsepower (TRLHP) of 4
horsepower. Note, tire/roll interface losses are not included
in these dynamometer coefficients.
(xii) Tire/Roll Interface Losses. Generic tire/roll interface losses shall be
determined for each dynamometer design used, and applied to obtain proper
vehicle loading. A means to select or determine the appropriate generic
tire/roll interface loss for each test vehicle shall be employed. Dynamometer
design parameters include roll diameter, roll spacing, and roll surface finish
Generic tire/roll interface losses may be determined by the acceptance
procedures in §85.2234(b)(4). Alternatively, generic values determined by
the Administrator, or by a procedure accepted by the Administrator, may be
used. The equation in (a)(2)(xiii) may be used to quantify tire/roll interface
losses.
(xiii) GTRL = { At * (Obmph) } + | (Bt) * (Obmph)2 } + { (Ct) * (Obmph)3 }
GTRL = Generic Tire/Roll Interface losses
At, Bt, and Ct are curve coefficients necessary to properly
characterize the tire/roll interface losses.
IM 2 40 Equipment Page 1 7
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§85 2226 §85 2226
(xiv) Indicated Horsepower. The power absorption for each test shall be selected
at 50 mph. The indicated power absorption (IHP) at 50 mph after accounting
for parasitic and generic tire losses shall be determined by the equation in
paragraph (a)(2)(xv).
(xv) IHP@ 50 mph = TRLHP@ 50 mph - PLHP@ 50 mph - GTRL@ 5Q 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 = TRLHP@ Obmph ' PLHP@ Obmph • GTRL<8> 50 mph
(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 tue
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 specifications in EPA RFP Number C100081T1.
Exceptions to the RFP specifications may be allowed upon a determination
by the Administrator that such exceptions would not significantly increase
/A/240 Equipment Page 18
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$85 2226 §85 2226
vehicle loading or emissions for the purpose of properly conducting an
approved short test. RFP C100081T1 is incorporated by reference.
(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 the 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 travelled. 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 two 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 shall be capable of safely restraining the veliicle 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 veliicle. 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 and shall not damage the four wheel
drive system. Front and rear wheel rolls shall maintain speed
synchronization within 0.2 mph.
(v) Augmented Braking. The dynamometer controls may provide for driver
hand-actuated augmented braking during decelerations in the transient driving
cycle. The dynamometer controls shall prevent operation of hand-actuated
augmented braking except during seconds 85 through 95 and after second
223 of the transient driving cycle. Hand-actuated augmented braking may be
allowed on other portions of the transient driving cycle upon a determination
by the Administrator that such additional augmentation would improve the
ability to follow the driving cycle without adversely affecting emission
levels. Fully automatic augmented braking may be used if it is automatically
interlocked such that it can be actuated only while the vehicle brakes are
applied, and simultaneous engine acceleration is systematically prevented.
(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
IM240 Equipment Page 19
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§85 2226 §85.2226
vehicle exhaust samples. The CVS system and components shall generally
conform to the specifications in §86.109-90.
(ii) CVS Row 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 (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®.
(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 tailpipe(s) in the center of the
/A/240 Equipment Page 20
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§85.2226 §8j 2226
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.
(ui) Dual Exhaust. 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
(1) General Requirements.
(i) The emission analysis system shall automatically sample, integrate, and
record the specified emission values for HC, CO, CO2, 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 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.
/A/240 Equipment Page 21
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§85 2226 §85.2226
(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 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
requirements and the quality control specifications in §85.2234(d) apply to
both analyzers.
(iii) Carbon Dioxide Analysis. C02 analysis shall be determined using an NDIR
analyzer. If a 700 SCFM CVS is used, CC*2 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 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 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.
(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
IM240 Equipment Page 22
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585 2226 §85 2226
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 tiie driving trace.
(ui) 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®-
(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.
IM240 Equipment Page 23
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§85.2227 §85.2227
§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.
(i) Flow Capacity. Up to 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. 1 second maximum to 90% of a step change measured with
air.
(v) Accuracy.
(A) ±1% of full scale as specified in (a)(2)(i) above 10 liters per
minute (rate)
(B) ±0.15 liters per minute between 0 and 10 liters per minute (rate)
(C) ±1% of full scale as specified in (a)(2)(iv) (total flow volume)
(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 24
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§85.2227 §85.2227
(b) Evaporative System Integrity Analysis System
(L) 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.
(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 25
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§85.2234 §85.2234
§85.2234 IM240 Test Quality Control Requirements
(a) General Requirements
(1) Minimums. 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 modify 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-dyno 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, or ±7% on the 22 to 18 mph coast-
down, official testing shall automatically be prevented, and corrective action
shall be taken to bring the dynamometer into calibration. 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%. official testing shall automatically be prevented, and corrective action
shall be taken to bring the dynamometer into calibration.
(iv) The clock used to check the coast-down time shall be accurate to the nearest
0.01 seconds when summing 1000 seconds.
/A/240 Quality Control Page 26
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§85 2234 §85 2234
(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 die daily comparison. Accuracy of redundant systems shall be checked
monthly.
(3) Warm-Up. Dynamometers shall be in a warmed up condition for use in official
testing. Warm-up is defined as sufficient operation that allows the dynamometer to
meet the coast down tune (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 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
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.
(i) 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 tunes. 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 perfonnance 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 (IHP) and inertia weight for
die 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 die 22 mph to 18 mph coast down
times shall be recorded for the data collected in paragraph
(b)(4)(i)(C) of this section.
/A/240 Quality Control Page 27
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§85.2234 §83 2234
(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)(iii) 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)(bO 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)(4Xi)(H) of
thus section from the horsepower curve determined in paragraph
(b)(4)(i)(F) of this section. The tire loss curve (CTRL) 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
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
tune, 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 (bX4)(i)(K) of this section are within ±1 second of
the 55 mph to 45 mph of 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 at
least six. points across the range of loads used for vehicle testing. Physical
checking weights shall be traceable to N1ST 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.
IM240 Quality Control Page 28
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§85 2234 §83.2234
(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 genencally 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 detennined 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
(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 collective action.
(5) Leak Check. The vacuum portion of the sample system shall be checked for leaks
on a daily basis and each tune 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
IM240 Quality Control Page 29
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§83 2234 §85.2234
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 tune, and at least once per week. The check shall include the
complete sample system from the sample probe to the analyzer. Values obtained
during initial acceptance testing where the differences between the integrated
measurement and the bag measurement differed by no more than 5% shall be used as
the "fit for use" limits. Response times exceeding these limits 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, to determine that any changes in the static
tailpipe pressure, measured on a second-by-second basis within 3 inches of
the end of the tailpipe, do not exceed ±1.0 inch of water.
(ii) The abil ity 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 liigh, middle, 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 a positive connection to the tailpipe (i.e., the mixing tee will
be effectively moved downstream, as in typical FTP testing). The average
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, middle, and low ends of
engine displacement and inertia, with a positive 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.
(i) 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 the 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 CO2-
When both a low range analyzer and a high range analyzer are used for a
IM240 Quality Control Page 30
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4852234 §852234
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 no greater than 4th
order, and shall fit the data within 2.0% at each calibration point as specified
in §86.121-90, §86 122-78, §86.123-78, and §86.124-78. (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 zero or the up-scale span points drift by
more than 2.0% from the previous check (except for the first check of the day),
official testing shall be prevented and corrective action shall be taken to bring die
system into compliance.
(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 correcdy 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) Daily Cross-Checks. Each analyzer in a given facility shall analyze a sample of test
gas, on each operating day after the up-scale span check. The test gas shall be the
same gas, or gas mixture for all analyzers. The concentration of the gas shall be one
of three values corresponding to approximately 0.5 to 3 times the cutpoint (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 the daily cross-check. The value of the daily
checking sample may be determined by a gas divider. The deviation in analysis from
the concentration of the daily 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.
IM240 Quality Control Page 31
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§85 2234 §85 2234
(6) Weekly NOx Convenor Checks. The convenor efficiency of the NO2 to NO
convenor 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 of
the NO gas shall be in the range of 100-300 ppm. Alternative methods may be used
if approved by the Administrator.
(7) Weekly NO/NOx Flow Balance. The flow balance between the NO and NOx test
modes shall be checked weekly. The check may be combined with the NOx
convenor check as illustrated in EPA NVFEL Form 305-01.
(8) 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.
(9) 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 (d)(9)(iii).
_.-.-. _, FID response in ppmC
(in) Ratio of Methane Response = ppm CH4 in cylinder
(10) 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 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.
(11) Interference. CO and CO2 analyzers shall be checked for water vapor interference
prior to initial service, and on a yearly basis thereafter. For CO analyzers used with
a CVS of 700 SCFM or greater, a gas mixture of 4% CO2 in N2 or air bubbled
through water with a saturated-mixture temperature of 40°C shall produce a response
on the CO analyzer of no greater than 10 ppm at 40°C. For CO2 analyzers used with
a CVS of 700 SCFM or greater, a zero gas bubbled through water with a saturated-
mixture temperature of 40°C shall produce a response on the CO2 analyzer of no
greater than 40 ppm. For analyzers used with lower flow rate CVS units, the
allowable interference response shall be proportionately adjusted downward. The
yearly checks shall be performed on a high ambient temperature summer day. The
allowable interference level shall be adjusted to coincide with the saturated-mixture
temperature used. For the CO analyzer, a rejection ratio of 12,000 to 1 shall be used
for this calculation. A ratio of 2000 to 1 shall be used for CO2 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 32
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<)85 2234 §85 2234
(2) Calibration Gases. Gases used to generate and check calibration curves shall be
traceable to a NIST SRM. CRM. NTRM. or RGM 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 to for up-scale span adjustment, cross-checks, and for
mid-scale span checks shall be traceable to NIST SRM. CRM. NTRM. or RGM 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 C02. 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, CO2, 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 CO2, and 0.3 ppm NOx. Working zero grade air or
calibration zero grade air shall be used for the FID zero span gas. Working or
calibration zero grade nitrogen or air shall be used for CO, CO2, 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. 10th percentile and 90th
percentile of the composite emissions (HC, CO, CO2, 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
IM240 Quality Control Page 33
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§85 2234 §85 2234
causing the offset are found, such errors shall be corrected. The sample penod 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 die 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 FID CH4 response ratio
(xi) Level of the ambient background concentrations
IM240 Quality Control Page 34
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§85 2234 §85 2234
(xii) The average, median. 1Otrt percentile and 90^ percentile of the composite
emissions (HC, CO, CO2, and NOx) measured over the defined periodic
basis
(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 Chans for AJJ 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 Page 35
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§85.2235 §85.2235
§85.2235 Evaporative Test System Quality Control Requirements
(a) Evaporative Purge Analysis System Flow Checks
(1) 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 include a mid-scale rate
check, and a total flow volume check between 10 and 20 liters. Deviations greater
than ±5% of full scale 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.
Deviations exceeding 25% of point in 4 minutes, or 1 liter in 4 minutes, wluchever is
less, 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.
Evaporative Test Equipment Quality Control Page 36
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§85 2239 §8S 2239
§85.2239 Test Report - IM240 and Evaporative Tests
(a) General Test Report Information
(1) Vehicle Description.
(i) License plate number.
(u) 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 faded 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 1M240 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.
The reported score for the IM240 shall be selected based upon the following:
(i) If the emissions of any exhaust constituent on the composite EM240 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 constituent 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 constituent
and the Phase 2 score shall be reported.
(iii) If the emissions of any exhaust constituent 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 constituent and the composite score shall be
reported.
(3) 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 constituents for which standards apply.
(4) Second-bv-Second Measurements. For vehicles failing the IM240, a table or graph
showing the second-by-second emission levels, in grams per second for each
Test Report Page 37
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§852239 §852239
pollutant, 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.
Test Report Page 38
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§85 2231
§85 2231
§85.2231 Terms
(a) Definitions
(I) Track coast-down target time: The new vehicle certification track coast-down tune
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.
(3) Tier 1: 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.
(4) 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.
(b) Abbreviations
(1) CFV:
(2) CH4:
(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) LDGTl:
(17) LDGT2.
(18) LDGV:
(19) LVW
(20) mph:
(21) NDIR:
(22) N1ST:
(23) N02:
(24) NO:
(25) NOx:
(26) NVFEL:
(27) Obmpfc
(28) PLHP:
(29) ppm:
(30) ppmC:
(31) psi:
(32) RFP:
(33) RLHP
(34) rpm:
(35) SCFM:
Ciitical flow venrun
Methane
Carbon dioxide
Carbon monoxide
Certified reference material
constant volume sampler
Flame iomzation detector
Grains 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 the rolls are
not coupled
Parasitic horsepower loss at the observed dynamometer speed in mph
parts per million by volume
pans 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 39
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§85.2231 5852231
(36) SPC: Statistical process control
(37) SRM: Standard reference material
(38) SSV: Subsonic venturi
(39) TRLHP: Track road-load horsepower
Terms and Abbreviations Page 40
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