(a) This appendix specifies transient test intervals and duty
cycles for the engine and powertrain testing described in Sec. Sec.
1036.512 and 1036.514, as follows:
    (1) The transient test intervals and duty cycle for testing
engines involves a schedule of normalized engine speed and torque
values.
    (2) The transient test intervals and duty cycles for powertrain
testing involves a schedule of vehicle speeds and road grade.
Determine road grade at each point based on the peak rated power of
the powertrain system, Prated, determined in Sec.
1036.520 and road grade coefficients using the following equation:
Road grade = a [middot] P2rated + b [middot]
Prated + c
    (3) The operating schedules in this appendix in some cases
eliminate repetitive information by omitting 1 Hz records where
there is no change in values. Perform testing by continuing to
operate at the last specified values until the operating schedule
shows a change in values. The official operating schedule for
testing, cycle validation, and other purposes includes both the
specified and omitted values.
    (b) The following transient test interval applies for spark-
ignition engines and powertrains when testing over the duty cycle
specified in Sec.  1036.512:

Table 1 of Appendix B--Transient Test Interval for Spark-Ignition
Engines and Powertrains Under Sec.  1036.512

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    (c) The following transient test interval applies for
compression-ignition engines and powertrains when testing over the
duty cycle specified in Sec.  1036.512:

Table 2 of Appendix B--Transient Test Interval for Compression-Ignition
Engines and Powertrains Under Sec.  1036.512

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    (d) The following transient duty cycle applies for compression-
ignition engines and powertrains when testing under Sec.  1036.514:

Table 3 of Appendix B--Transient Duty Cycle for Compression-Ignition
Engines and Powertrains Under Sec.  1036.514
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Appendix C of Part 1036--Default Engine Fuel Maps for Sec.  1036.540

    GEM contains the default steady-state fuel maps in this appendix
for performing cycle-average engine fuel mapping as described in
Sec.  1036.505(b)(2). Note that manufacturers have the option to
replace these default values in GEM if they generate a steady-state
fuel map as described in Sec.  1036.535(b).
    (a) Use the following default fuel map for compression-ignition
engines that will be installed in Tractors and Vocational Heavy HDV:

Table 1 of Appendix C--Default Fuel Map for Compression-Ignition
Engines Installed in Tractors and Vocational Heavy HDV

[GRAPHIC] [TIFF OMITTED] TR24JA23.237

    (b) Use the following default fuel map for compression-ignition
engines that will be installed in Vocational Light HDV and
Vocational Medium HDV:

Table 2 of Appendix C--Default Fuel Map for Compression-Ignition
Engines Installed in Vocational Light HDV and Vocational Medium HDV

[GRAPHIC] [TIFF OMITTED] TR24JA23.238

    (c) Use the following default fuel map for all spark-ignition
engines:

Table 3 of Appendix C--Default Fuel Map for Spark-Ignition Engines

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PART 1037--CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES

0
93. The authority citation for part 1037 continues to read as follows:

    Authority: 42 U.S.C. 7401--7671q.

Subpart A [Amended]

0
94. Amend Sec.  1037.1 by revising paragraph (a) to read as follows:

Sec.  1037.1  Applicability.

    (a) The regulations in this part 1037 apply for all new heavy-duty
vehicles, except as provided in Sec. Sec.  1037.5 and 1037.104. This
includes electric vehicles, fuel cell vehicles, and vehicles fueled by
conventional and alternative fuels. This also includes certain trailers
as described in Sec. Sec.  1037.5, 1037.150, and 1037.801.
* * * * *

0
95. Amend Sec.  1037.5 by revising paragraph (e) to read as follows:

Sec.  1037.5  Excluded vehicles.

* * * * *
    (e) Vehicles subject to the heavy-duty emission standards of 40 CFR
part 86. See 40 CFR 86.1816 and 86.1819 for emission standards that
apply for these vehicles. This exclusion generally applies for complete
heavy-duty vehicles at or below 14,000 pounds GVWR.
* * * * *

0
96. Amend Sec.  1037.10 by revising paragraph (c) to read as follows:

Sec.  1037.10  How is this part organized?

* * * * *
    (c) Subpart C of this part describes how to apply for a certificate
of conformity.
* * * * *

0
97. Revise Sec.  1037.101 to read as follows:

Sec.  1037.101  Overview of emission standards.

    This part specifies emission standards for certain vehicles and for
certain pollutants. This part contains standards and other regulations
applicable to the emission of the air pollutant defined as the
aggregate group of six greenhouse gases: carbon dioxide, nitrous oxide,
methane, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.
    (a) You must show that vehicles meet the following emission
standards:
    (1) Exhaust emissions of criteria pollutants. Criteria pollutant
standards for NOX, HC, PM, and CO apply as described in
Sec.  1037.102. These pollutants are sometimes described collectively
as ``criteria pollutants'' because they are either criteria pollutants
under the Clean Air Act or precursors to the criteria pollutants ozone
and PM.
    (2) Exhaust emissions of greenhouse gases. These pollutants are
described collectively in this part as ``greenhouse gas pollutants''
because they are regulated primarily based on their impact on the
climate. Emission standards apply as follows for greenhouse gas (GHG)
emissions:
    (i) CO2, CH4, and N2O emission
standards apply as described in Sec. Sec.  1037.105 through 1037.107.
    (ii) Hydrofluorocarbon standards apply as described in Sec.
1037.115(e). These pollutants are also ``greenhouse gas pollutants''
but are treated separately from exhaust greenhouse gas pollutants
listed in paragraph (b)(2)(i) of this section.
    (3) Fuel evaporative and refueling emissions. Requirements related
to fuel evaporative and refueling emissions are described in Sec.
1037.103.
    (b) The regulated heavy-duty vehicles are addressed in different
groups as follows:
    (1) For criteria pollutants, vocational vehicles and tractors are
regulated based on gross vehicle weight rating (GVWR), whether they are
considered ``spark-ignition'' or ``compression-ignition,'' and whether
they are first sold as complete or incomplete vehicles.
    (2) For greenhouse gas pollutants, vehicles are regulated in the
following groups:
    (i) Tractors above 26,000 pounds GVWR.
    (ii) Trailers.
    (iii) Vocational vehicles.
    (3) The greenhouse gas emission standards apply differently
depending on the vehicle service class as described in Sec.  1037.140.
In addition, standards apply differently for vehicles with spark-
ignition and compression-ignition engines. References in this part 1037
to ``spark-ignition'' or ``compression-ignition'' generally relate to
the application of standards under 40 CFR 1036.140. For example, a
vehicle with an engine certified to spark-ignition standards under 40
CFR part 1036 is generally subject to requirements under this part 1037
that apply for spark-ignition vehicles. However, note that emission
standards for Heavy HDE are considered to be compression-ignition
standards for purposes of applying vehicle emission standards under
this part. Also, for spark-ignition engines voluntarily certified as
compression-ignition engines under 40 CFR part 1036, you must choose at
certification whether your vehicles are subject to spark-ignition
standards or compression-ignition standards.
    (4) For evaporative and refueling emissions, vehicles are regulated
based on the type of fuel they use. Vehicles fueled with volatile
liquid fuels or gaseous fuels are subject to evaporative and refueling
emission standards.

0
98. Revise Sec.  1037.102 to read as follows:

Sec.  1037.102  Exhaust emission standards for NOX, HC, PM, and CO.

    (a) Engines installed in heavy-duty vehicles are subject to
criteria pollutant standards for NOX, HC, PM, and CO under
40 CFR part 86 through model year 2026 and 40 CFR part 1036 for model
years 2027 and later.
    (b) Heavy-duty vehicles with no installed propulsion engine, such
as electric vehicles, are subject to criteria pollutant standards under
this part. The emission standards that apply are the same as the
standards that apply for compression-ignition engines under 40 CFR
86.007-11 and 1036.104 for a given model year.
    (1) You may state in the application for certification that
vehicles with no installed propulsion engine comply with all the
requirements of this part related to criteria emission standards
instead of submitting test data. Tailpipe emissions of criteria
pollutants from vehicles with no installed propulsion engine are deemed
to be zero.
    (2) Vehicles with no installed propulsion engines may not generate
NOX credits.

0
99. Amend Sec.  1037.103 by:
0
a. Revising paragraph (b)(1);
0
b. Removing paragraph (b)(6); and
0
c. Revising paragraphs (f) and (g)(1) and (2).
    The revisions read as follows:

Sec.  1037.103  Evaporative and refueling emission standards.

* * * * *
    (b) * * *
    (1) The refueling standards in 40 CFR 86.1813-17(b) and the related
provisions in 40 CFR part 86, subpart S, apply to complete vehicles
starting in model year 2022. Those standards and related provisions
apply for incomplete vehicles starting in model year 2027, or as
described in the alternate phase-in schedule described in 40 CFR
86.1813-17(b). If you do not certify all your incomplete heavy-duty
vehicles above 14,000 pounds GVWR to the refueling standards in model
year 2027, you must use the alternate phase-in schedule described in 40
CFR 86.1813-17(b).
* * * * *
    (f) Useful life. The evaporative and refueling emission standards
of this section apply for the full useful life, expressed in service
miles or calendar years, whichever comes first. The useful life values
for the standards of this section are the same as the values described
for evaporative emission standards in 40 CFR 86.1805.
    (g) * * *
    (1) Auxiliary engines and associated fuel-system components must be
installed when testing fully assembled vehicles. If the auxiliary
engine draws fuel from a separate fuel tank, you must fill the extra
fuel tank before the start of diurnal testing as described for the
vehicle's main fuel tank. Use good engineering judgment to ensure that
any nonmetal portions of the fuel system related to the auxiliary
engine have reached stabilized levels of permeation emissions. The
auxiliary engine must not operate during the running loss test or any
other portion of testing under this section.
    (2) For testing with partially assembled vehicles, you may omit
installation of auxiliary engines and associated fuel-system components
as long as those components installed in the final configuration are
certified to meet the applicable emission standards for Small SI
equipment described in 40 CFR 1054.112 or for Large SI engines in 40
CFR 1048.105. For any fuel-system components that you do not install,
your installation instructions must describe this certification
requirement.

0
100. Amend Sec.  1037.105 by:
0
a. Revising paragraph (g)(2);
0
b. Amending paragraph (h)(1) by revising footnote a in Table 5; and
0
c. Revising paragraphs (h)(5) through (7).
    The revisions read as follows:

Sec.  1037.105  CO2 emission standards for vocational vehicles.

* * * * *
    (g) * * *

    (2) Class 8 hybrid vehicles with Light HDE or Medium HDE may be
certified to compression-ignition standards for the Heavy HDV service
class. You may generate and use credits as allowed for the Heavy HDV
service class.
* * * * *
    (h) * * *
    (1) * * *

                          Table 5 of Sec.   1037.105--Phase 2 Custom Chassis Standards
                                                  [g/ton-mile]
----------------------------------------------------------------------------------------------------------------
                Vehicle type a                  Assigned vehicle service class     MY 2021-2026      MY 2027+
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
\a\ Vehicle types are generally defined in Sec.   1037.801. ``Other bus'' includes any bus that is not a school
  bus or a coach bus. A ``mixed-use vehicle'' is one that meets at least one of the criteria specified in Sec.
  1037.631(a)(1) or (2).

* * * * *
    (5) Emergency vehicles are deemed to comply with the standards of
this paragraph (h) if they use tires with TRRL at or below 8.4 N/kN
(8.7 N/kN for model years 2021 through 2026).
    (6) Concrete mixers and mixed-use vehicles are deemed to comply
with the standards of this paragraph (h) if they use tires with TRRL at
or below 7.1 N/kN (7.6 N/kN for model years 2021 through 2026).
    (7) Motor homes are deemed to comply with the standards of this
paragraph (h) if they have tires with TRRL at or below 6.0 N/kN (6.7 N/
kN for model years 2021 through 2026) and automatic tire inflation
systems or tire pressure monitoring systems with wheels on all axles.
* * * * *

0
101. Amend Sec.  1037.106 by revising paragraph (f)(1) to read as
follows:

Sec.  1037.106  Exhaust emission standards for tractors above 26,000
pounds GVWR.

* * * * *
    (f) * * *
    (1) You may optionally certify 4x2 tractors with Heavy HDE to the
standards and useful life for Class 8 tractors, with no restriction on
generating or using emission credits within the Class 8 averaging set.
* * * * *

0
102. Amend Sec.  1037.115 by revising paragraphs (a) and (e)(3) to read
as follows:

Sec.  1037.115  Other requirements.

* * * * *
    (a) Adjustable parameters. Vehicles that have adjustable parameters
must meet all the requirements of this part for any adjustment in the
practically adjustable range. We may require that you set adjustable
parameters to any specification within the practically adjustable range
during any testing. See 40 CFR 1068.50 for general provisions related
to adjustable parameters. You must ensure safe vehicle operation
throughout the practically adjustable range of each adjustable
parameter, including consideration of production tolerances. Note that
adjustable roof fairings and trailer rear fairings are deemed not to be
adjustable parameters.
* * * * *
    (e) * * *
    (3) If air conditioning systems are designed such that a compliance
demonstration under 40 CFR 86.1867-12(a) is impossible or impractical,
you may ask to use alternative means to demonstrate that your air
conditioning system achieves an equivalent level of control.

0
103. Amend Sec.  1037.120 by revising paragraph (c) to read as follows:

Sec.  1037.120  Emission-related warranty requirements.

* * * * *
    (c) Components covered. The emission-related warranty covers tires,
automatic tire inflation systems, tire pressure monitoring systems,
vehicle speed limiters, idle-reduction systems, hybrid system
components, and devices added to the vehicle to improve aerodynamic
performance (not including standard components such as hoods or mirrors
even if they have been optimized for aerodynamics) to the extent such
emission-related components are included in your application for
certification. The emission-related warranty also covers other added
emission-related components to the extent they are included in your
application for certification. The emission-related warranty covers all
components whose failure would increase a vehicle's emissions of air
conditioning refrigerants (for vehicles subject to air conditioning
leakage standards), and it covers all components whose failure would
increase a vehicle's evaporative and refueling emissions (for vehicles
subject to evaporative and refueling emission standards). The emission-
related warranty covers components that are part of your certified
configuration even if another company produces the component. Your
emission-related warranty does not need to cover components whose
failure would not increase a vehicle's emissions of any regulated
pollutant.
* * * * *

0
104. Amend Sec.  1037.125 by revising paragraphs (a) and (d) to read as
follows:

Sec.  1037.125  Maintenance instructions and allowable maintenance.

* * * * *
    (a) Critical emission-related maintenance. Critical emission-
related maintenance includes any adjustment, cleaning, repair, or
replacement of critical emission-related components. Critical emission-
related maintenance may also include additional emission-related
maintenance that you determine is critical if we approve it in advance.
You may schedule critical emission-related maintenance on these
components if you demonstrate that the maintenance is reasonably likely
to be done at the recommended intervals on in-use vehicles. We will
accept scheduled maintenance as reasonably likely to occur if you
satisfy any of the following conditions:
* * * * *
    (d) Noncritical emission-related maintenance. Subject to the
provisions of this paragraph (d), you may schedule any amount of
emission-related inspection or maintenance that is not covered by
paragraph (a) of this section (that is, maintenance that is neither
explicitly identified as critical emission-related maintenance, nor
that we approve as critical emission-related maintenance). Noncritical
emission-related maintenance generally includes maintenance on the
components we specify in 40 CFR part 1068, appendix A, that is not
covered in paragraph (a) of this section. You must state in the owners
manual that these steps are not necessary to keep the emission-related
warranty valid. If operators fail to do this maintenance, this does not
allow you to disqualify those vehicles from in-use testing or deny a
warranty claim. Do

not take these inspection or maintenance steps during service
accumulation on your emission-data vehicles.
* * * * *

0
105. Amend Sec.  1037.130 by revising paragraph (b)(3) to read as
follows:

Sec.  1037.130  Assembly instructions for secondary vehicle
manufacturers.

* * * * *
    (b) * * *
    (3) Describe the necessary steps for installing emission-related
diagnostic systems.
* * * * *

0
106. Amend Sec.  1037.135 by revising paragraph (c)(6) to read as
follows:

Sec.  1037.135  Labeling.

* * * * *
    (c) * * *
    (6) Identify the emission control system. Use terms and
abbreviations as described in appendix C to this part or other
applicable conventions. Phase 2 tractors and Phase 2 vocational
vehicles may omit this information.
* * * * *

0
107. Amend Sec.  1037.140 by revising paragraph (g) to read as follows:

Sec.  1037.140  Classifying vehicles and determining vehicle
parameters.

* * * * *
    (g) The standards and other provisions of this part apply to
specific vehicle service classes for tractors and vocational vehicles
as follows:
    (1) Phase 1 and Phase 2 tractors are divided based on GVWR into
Class 7 tractors and Class 8 tractors. Where provisions of this part
apply to both tractors and vocational vehicles, Class 7 tractors are
considered ``Medium HDV'' and Class 8 tractors are considered ``Heavy
HDV''. This paragraph (g)(1) applies for hybrid and non-hybrid
vehicles.
    (2) Phase 1 vocational vehicles are divided based on GVWR. ``Light
HDV'' includes Class 2b through Class 5 vehicles; ``Medium HDV''
includes Class 6 and Class 7 vehicles; and ``Heavy HDV'' includes Class
8 vehicles.
    (3) Phase 2 vocational vehicles propelled by engines subject to the
spark-ignition standards of 40 CFR part 1036 are divided as follows:
    (i) Class 2b through Class 5 vehicles are considered ``Light HDV''.
    (ii) Class 6 through Class 8 vehicles are considered ``Medium
HDV''.
    (4) Phase 2 vocational vehicles propelled by engines subject to the
compression-ignition standards in 40 CFR part 1036 are divided as
follows:
    (i) Class 2b through Class 5 vehicles are considered ``Light HDV''.
    (ii) Class 6 through 8 vehicles are considered ``Heavy HDV'' if the
installed engine's primary intended service class is Heavy HDE (see 40
CFR 1036.140), except that Class 8 hybrid vehicles are considered
``Heavy HDV'' regardless of the engine's primary intended service
class.
    (iii) All other Class 6 through Class 8 vehicles are considered
``Medium HDV''.
    (5) Heavy-duty vehicles with no installed propulsion engine, such
as electric vehicles, are divided as follows:
    (i) Class 2b through Class 5 vehicles are considered ``Light HDV''.
    (ii) Class 6 and 7 vehicles are considered ``Medium HDV''.
    (iii) Class 8 vehicles are considered ``Heavy HDV''.
    (6) In certain circumstances, you may certify vehicles to standards
that apply for a different vehicle service class. For example, see
Sec. Sec.  1037.105(g) and 1037.106(f). If you optionally certify
vehicles to different standards, those vehicles are subject to all the
regulatory requirements as if the standards were mandatory.
* * * * *

0
108. Amend Sec.  1037.150 by revising paragraphs (f) and (y)(1) to read
as follows:

Sec.  1037.150  Interim provisions.

* * * * *
    (f) Electric and hydrogen fuel cell vehicles. Tailpipe emissions of
regulated GHG pollutants from electric vehicles and hydrogen fuel cell
vehicles are deemed to be zero. No CO2-related emission
testing is required for electric vehicles or hydrogen fuel cell
vehicles. Use good engineering judgment to apply other requirements of
this part to electric vehicles.
* * * * *
    (y) * * *
    (1) For vocational Light HDV and vocational Medium HDV, emission
credits you generate in model years 2018 through 2021 may be used
through model year 2027, instead of being limited to a five-year credit
life as specified in Sec.  1037.740(c). For Class 8 vocational vehicles
with Medium HDE, we will approve your request to generate these credits
in and use these credits for the Medium HDV averaging set if you show
that these vehicles would qualify as Medium HDV under the Phase 2
program as described in Sec.  1037.140(g)(4).
* * * * *

0
109. Amend Sec.  1037.201 by revising paragraph (h) to read as follows:

Sec.  1037.201  General requirements for obtaining a certificate of
conformity.

* * * * *
    (h) The certification and testing provisions of 40 CFR part 86,
subpart S, apply instead of the provisions of this subpart relative to
the evaporative and refueling emission standards specified in Sec.
1037.103, except that Sec.  1037.243 describes how to demonstrate
compliance with evaporative and refueling emission standards. For
vehicles that do not use an evaporative canister for controlling
diurnal emissions, you may certify with respect to exhaust emissions
and use the provisions of Sec.  1037.622 to let a different company
certify with respect to evaporative emissions.
* * * * *

0
110. Amend Sec.  1037.205 by revising paragraphs (e) and (p), and
adding paragraph (q) to read as follows:

Sec.  1037.205  What must I include in my application?

* * * * *
    (e) Describe any test equipment and procedures that you used,
including any special or alternate test procedures you used (see Sec.
1037.501). Include information describing the procedures you used to
determine CdA values as specified in Sec. Sec.  1037.525
through 1037.527. Describe which type of data you are using for engine
fuel maps (see 40 CFR 1036.505). If your trailer certification relies
on approved data from device manufacturers, identify the device and
device manufacturer.
* * * * *
    (p) Where applicable, describe all adjustable operating parameters
(see Sec.  1037.115), including production tolerances. For any
operating parameters that do not qualify as adjustable parameters,
include a description supporting your conclusion (see 40 CFR
1068.50(c)). Include the following in your description of each
adjustable parameter:
    (1) The nominal or recommended setting.
    (2) The intended practically adjustable range.
    (3) The limits or stops used to establish adjustable ranges.
    (4) Information showing why the limits, stops, or other means of
inhibiting adjustment are effective in preventing adjustment of
parameters on in-use engines to settings outside your intended
practically adjustable ranges.
    (q) Include the following information for electric vehicles and
fuel cell vehicles to show they meet the standards of this part:

    (1) You may attest that vehicles comply with the standards of Sec.
1037.102 instead of submitting test data.
    (2) For vehicles generating credits under Sec.  1037.616, you may
attest that the vehicle meets the durability requirements described in
Sec.  1037.102(b)(3) based on an engineering analysis of measured
values and other information, consistent with good engineering
judgment, instead of testing at the end of the useful life. Send us
your test results for work produced over the FTP and initial useable
battery energy or initial fuel cell voltage. Also send us your
engineering analysis describing how you meet the durability
requirements if we ask for it.
* * * * *

0
111. Amend Sec.  1037.225 by revising the introductory text and
paragraph (g) to read as follows:

Sec.  1037.225  Amending applications for certification.

    Before we issue you a certificate of conformity, you may amend your
application to include new or modified vehicle configurations, subject
to the provisions of this section. After we have issued your
certificate of conformity, you may send us an amended application any
time before the end of the model year requesting that we include new or
modified vehicle configurations within the scope of the certificate,
subject to the provisions of this section. You must amend your
application if any changes occur with respect to any information that
is included or should be included in your application.
* * * * *
    (g) You may produce vehicles or modify in-use vehicles as described
in your amended application for certification and consider those
vehicles to be in a certified configuration. Modifying a new or in-use
vehicle to be in a certified configuration does not violate the
tampering prohibition of 40 CFR 1068.101(b)(1), as long as this does
not involve changing to a certified configuration with a higher family
emission limit. See Sec.  1037.621(g) for special provisions that apply
for changing to a different certified configuration in certain
circumstances.

0
112. Amend Sec.  1037.230 by revising paragraph (c) to read as follows:

Sec.  1037.230  Vehicle families, sub-families, and configurations.

* * * * *
    (c) Group vehicles into configurations consistent with the
definition of ``vehicle configuration'' in Sec.  1037.801. Note that
vehicles with hardware or software differences that are related to
measured or modeled emissions are considered to be different vehicle
configurations even if they have the same modeling inputs and FEL. Note
also, that you are not required to separately identify all
configurations for certification. Note that you are not required to
identify all possible configurations for certification; also, you are
required to include in your final ABT report only those configurations
you produced.
* * * * *

0
113. Amend Sec.  1037.231 by revising paragraph (b)(1) to read as
follows:

Sec.  1037.231  Powertrain families.

* * * * *
    (b) * * *
    (1) Engine family as specified in 40 CFR 1036.230.
* * * * *

0
114. Amend Sec.  1037.243 by revising the section heading and
paragraphs (a) and (b) to read as follows:

Sec.  1037.243  Demonstrating compliance with evaporative and refueling
emission standards.

    (a) For purposes of certification, your vehicle family is
considered in compliance with the evaporative and refueling emission
standards in subpart B of this part if you prepare an engineering
analysis showing that your vehicles in the family will comply with
applicable standards throughout the useful life, and there are no test
results from an emission-data vehicle representing the family that
exceed an emission standard.
    (b) Your evaporative refueling emission family is deemed not to
comply if your engineering analysis is not adequate to show that all
the vehicles in the family will comply with applicable emission
standards throughout the useful life, or if a test result from an
emission-data vehicle representing the family exceeds an emission
standard.
* * * * *

0
115. Amend Sec.  1037.250 by revising paragraph (a) to read as follows:

Sec.  1037.250  Reporting and recordkeeping.

    (a) By September 30 following the end of the model year, send the
Designated Compliance Officer a report including the total U.S.-
directed production volume of vehicles you produced in each vehicle
family during the model year (based on information available at the
time of the report). Report by vehicle identification number and
vehicle configuration and identify the subfamily identifier. Report
uncertified vehicles sold to secondary vehicle manufacturers. We may
waive the reporting requirements of this paragraph (a) for small
manufacturers.
* * * * *

0
116. Amend Sec.  1037.320 by revising paragraph (b) to read as follows
and removing Table 1 to Sec.  1037.320:

Sec.  1037.320  Audit procedures for axles and transmissions.

* * * * *
    (b) Run GEM with the define vehicles to determine whether the
transmission or axle family passes the audit.
    (1) For transmission audits, run GEM for each applicable vehicle
configuration and GEM regulatory subcategory identified in 40 CFR
1036.540 and for each vehicle class as defined in Sec.  1037.140(g)
using the applicable default engine map in appendix C of 40 CFR part
1036, the cycle-average fuel map in Table 1 of this section, the torque
curve in Table 2 of this section for both the engine full-load torque
curve and parent engine full-load torque curve, the motoring torque
curve in Table 3 of this section, the idle fuel map in Table 4 of this
section. For transmission testing, use the test transmission's gear
ratios in place of the gear ratios defined in 40 CFR 1036.540. Table 1
through Table 4 follow:

                                                Table 1 to Paragraph (b)(1) of Sec.   1037.320--Transient Cycle-Average Fuel Map by Vehicle Class
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
             Light HDV and medium HDV--spark-ignition                       Light HDV and medium HDV--compression-ignition                                    Heavy HDV
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Engine cycle                             Idle                      Engine cycle                            Idle                     Engine cycle                         Idle
      work         N/V (r/      Fuel    speed (r/    Idle torque         work         N/V (r/   Fuel mass  speed (r/  Idle torque         work        N/V (r/    Fuel    speed (r/  Idle torque
 (kW[middot]hr)      min)     mass (g)     min)     (N[middot]m)    (kW[middot]hr)      min)       (g)       min)     (N[middot]m)   (kW[middot]hr)    min)    mass (g)    min)     (N[middot]m)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
     3.5404         2.8739    1109.31      600.5       37.997            3.3057        2.3317     919.01      750.3      36.347         11.4255        2.3972   2579.58     600.7      89.658
     3.6574         3.0198    1153.35      600.4       37.951            3.3822        2.5075     982.53      750.2      36.461         11.6112        2.2432   2591.08     601.2      90.428
     3.8119         3.0370    1188.66      600.2       37.956            3.4917        2.5320     998.64      750.2      36.608         12.5052        2.1620   2763.28     602.4      92.014
     4.0121         3.1983    1250.76      600.1       38.153            3.6087        2.6181    1036.34      750.2      36.734         17.7747        2.5195   3835.77     602.2      91.780

     5.5567         3.1325    1585.32      604.6       56.535            5.2397        2.5050    1354.33      753.0      51.992         18.4901        2.4155   3994.29     603.5      93.724
     5.6814         3.2956    1639.08      604.0       56.549            5.3153        2.7289    1417.20      751.9      51.488         20.1904        2.3800   4374.06     605.1      96.340
     5.8720         3.3255    1686.14      602.5       56.234            5.4112        2.6689    1416.75      751.3      51.280     ...............  ........  ........  ........  .............
     6.1774         3.4848    1773.39      601.7       56.038            5.5590        2.7231    1450.67      751.0      51.254     ...............  ........  ........  ........  .............
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

                                Table 2 to Paragraph (b)(1) of Sec.   1037.320--Full-Load Torque Curves by Vehicle Class
--------------------------------------------------------------------------------------------------------------------------------------------------------
      Light HDV and medium HDV--spark-ignition         Light HDV and medium HDV--compression-ignition                       Heavy HDV
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Engine torque                                      Engine torque                                     Engine torque
   Engine speed (r/min)          (N[middot]m)          Engine speed (r/min)         (N[middot]m)          Engine speed (r/min)         (N[middot]m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  600                       433                       750                      470                       600                     1200
                  700                       436                       907                      579                       750                     1320
                  800                       445                      1055                      721                       850                     1490
                  900                       473                      1208                      850                       950                     1700
                 1000                       492                      1358                      876                      1050                     1950
                 1100                       515                      1507                      866                      1100                     2090
                 1200                       526                      1660                      870                      1200                     2100
                 1300                       541                      1809                      868                      1250                     2100
                 1400                       542                      1954                      869                      1300                     2093
                 1500                       542                      2105                      878                      1400                     2092
                 1600                       542                      2258                      850                      1500                     2085
                 1700                       547                      2405                      800                      1520                     2075
                 1800                       550                      2556                      734                      1600                     2010
                 1900                       551                      2600                        0                      1700                     1910
                 2000                       554      .......................  ........................                  1800                     1801
                 2100                       553      .......................  ........................                  1900                     1640
                 2200                       558      .......................  ........................                  2000                     1350
                 2300                       558      .......................  ........................                  2100                      910
                 2400                       566      .......................  ........................                  2250                        0
                 2500                       571
                 2600                       572
                 2700                       581
                 2800                       586
                 2900                       587
                 3000                       590
                 3100                       591
                 3200                       589
                 3300                       585
                 3400                       584
                 3500                       582
                 3600                       573
                 3700                       562
                 3800                       555
                 3900                       544
                 4000                       534
                 4100                       517
                 4200                       473
                 4291                       442
                 4500                       150
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                 Table 3 to Paragraph (b)(1) of Sec.   1037.320--Motoring Torque Curves by Vehicle Class
--------------------------------------------------------------------------------------------------------------------------------------------------------
      Light HDV and medium HDV--spark-ignition         Light HDV and medium HDV--compression-ignition                       Heavy HDV
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Engine torque                                      Engine torque                                     Engine torque
   Engine speed (r/min)          (N[middot]m)          Engine speed (r/min)         (N[middot]m)          Engine speed (r/min)         (N[middot]m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  700                       -41                       750                     -129                       600                      -98
                  800                       -42                       907                     -129                       750                     -121
                  900                       -43                      1055                     -130                       850                     -138
                 1000                       -45                      1208                     -132                       950                     -155
                 1100                       -48                      1358                     -135                      1050                     -174
                 1200                       -49                      1507                     -138                      1100                     -184
                 1300                       -50                      1660                     -143                      1200                     -204

                 1411                       -51                      1809                     -148                      1250                     -214
                 1511                       -52                      1954                     -155                      1300                     -225
                 1611                       -53                      2105                     -162                      1400                     -247
                 1711                       -56                      2258                     -170                      1500                     -270
                 1811                       -56                      2405                     -179                      1520                     -275
                 1911                       -57                      2556                     -189                      1600                     -294
                 2011                       -57      .......................  ........................                  1700                     -319
                 2111                       -58      .......................  ........................                  1800                     -345
                 2211                       -60      .......................  ........................                  1900                     -372
                 2311                       -65      .......................  ........................                  2000                     -400
                 2411                       -81      .......................  ........................                  2100                     -429
                 2511                       -85
                 2611                       -87
                 2711                       -88
                 2811                       -89
                 2911                       -91
                 3011                       -91
                 3111                       -96
                 3211                       -96
                 3311                       -97
                 3411                       -98
                 3511                       -99
                 3611                      -104
                 3711                      -105
                 3811                      -108
                 3911                      -108
                 4011                      -111
                 4111                      -111
                 4211                      -115
                 4291                      -112
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                 Table 4 to Paragraph (b)(1) of Sec.   1037.320--Engine Idle Fuel Maps by Vehicle Class
--------------------------------------------------------------------------------------------------------------------------------------------------------
      Light HDV and medium HDV-- spark-ignition         Light HDV and medium HDV-- compression-ignition                      Heavy HDV
--------------------------------------------------------------------------------------------------------------------------------------------------------
 Engine speed (r/   Engine torque   Fuel mass rate (g/ Engine speed (r/  Engine torque   Fuel mass rate    Engine speed    Engine torque  Fuel mass rate
       min)          (N[middot]m)           s)               min)        (N[middot]m)         (g/s)           (r/min)      (N[middot]m)        (g/s)
--------------------------------------------------------------------------------------------------------------------------------------------------------
            600                 0            0.4010               750               0           0.2595              600               0          0.3501
            700                 0            0.4725               850               0           0.2626              700               0          0.4745
            600               100            0.6637               750             100           0.6931              600             100          0.6547
            700               100            0.7524               850             100           0.7306              700             100          0.8304
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (2) Follow the procedure in paragraph (b)(1) of this section for
axle audits, but cover the range of tire sizes by using good
engineering judgment to select three representative tire sizes for each
axle ratio for each vehicle configuration instead of using the tire
size determined in 40 CFR 1036.540.
    (3) The GEM ``Default FEL CO2 Emissions'' result for
each vehicle configuration counts as a separate test for determining
whether the family passes the audit. For vocational vehicles, use the
GEM ``Default FEL CO2 Emissions'' result for the Regional
subcategory.
* * * * *

0
117. Amend Sec.  1037.510 by revising paragraphs (a)(1)(i), (2), and
(3) and (d) to read as follows:

Sec.  1037.510  Duty-cycle exhaust testing.

* * * * *
    (a) * * *
    (1) * * *
    (i) Transient cycle. The transient cycle is specified in appendix A
of this part. Warm up the vehicle. Start the duty cycle within 30
seconds after concluding the preconditioning procedure. Start sampling
emissions at the start of the duty cycle.
* * * * *
    (2) Perform cycle-average engine fuel mapping as described in 40
CFR 1036.540. For powertrain testing under Sec.  1037.550 or Sec.
1037.555, perform testing as described in this paragraph (a)(2) to
generate GEM inputs for each simulated vehicle configuration, and test
runs representing different idle conditions. Perform testing as
follows:
    (i) Transient cycle. The transient cycle is specified in appendix A
of this part.
    (ii) Highway cruise cycles. The grade portion of the route
corresponding to the 55 mi/hr and 65 mi/hr highway cruise cycles is
specified in appendix D of this part. Maintain vehicle speed between -
1.0 mi/hr and 3.0 mi/hr of the speed setpoint; this speed tolerance
applies instead of the approach specified in 40 CFR 1066.425(b)(1) and
(2).
    (iii) Drive idle. Perform testing at a loaded idle condition for
Phase 2 vocational vehicles. For engines with an adjustable warm idle
speed setpoint, test at the minimum warm idle speed and the maximum
warm idle speed;

otherwise simply test at the engine's warm idle speed. Warm up the
powertrain as described in 40 CFR 1036.520(c)(1). Within 60 seconds
after concluding the warm-up, linearly ramp the powertrain down to zero
vehicle speed over 20 seconds. Apply the brake and keep the
transmission in drive (or clutch depressed for manual transmission).
Stabilize the powertrain for (60 1) seconds and then sample
emissions for (30 1) seconds.
    (iv) Parked idle. Perform testing at a no-load idle condition for
Phase 2 vocational vehicles. For engines with an adjustable warm idle
speed setpoint, test at the minimum warm idle speed and the maximum
warm idle speed; otherwise simply test at the engine's warm idle speed.
Warm up the powertrain as described in 40 CFR 1036.520(c)(1). Within 60
seconds after concluding the warm-up, linearly ramp the powertrain down
to zero vehicle speed in 20 seconds. Put the transmission in park (or
neutral for manual transmissions and apply the parking brake if
applicable). Stabilize the powertrain for (180 1) seconds
and then sample emissions for (600 1) seconds.
    (3) Where applicable, perform testing on a chassis dynamometer as
follows:
    (i) Transient cycle. The transient cycle is specified in appendix A
of this part. Warm up the vehicle by operating over one transient
cycle. Within 60 seconds after concluding the warm up cycle, start
emission sampling and operate the vehicle over the duty cycle.
    (ii) Highway cruise cycle. The grade portion of the route
corresponding to the 55 mi/hr and 65 mi/hr highway cruise cycles is
specified in appendix D of this part. Warm up the vehicle by operating
it at the appropriate speed setpoint over the duty cycle. Within 60
seconds after concluding the preconditioning cycle, start emission
sampling and operate the vehicle over the duty cycle, maintaining
vehicle speed within 1.0 mi/hr of the speed setpoint; this
speed tolerance applies instead of the approach specified in 40 CFR
1066.425(b)(1) and (2).
* * * * *
    (d) For highway cruise and transient testing, compare actual
second-by-second vehicle speed with the speed specified in the test
cycle and ensure any differences are consistent with the criteria as
specified in Sec.  1037.550(g)(1). If the speeds do not conform to
these criteria, the test is not valid and must be repeated.
* * * * *

0
118. Amend Sec.  1037.520 by revising paragraphs (c)(2) and (3), (f),
and (h)(1) to read as follows:

Sec.  1037.520  Modeling CO2 emissions to show compliance
for vocational vehicles and tractors.

* * * * *
    (c) * * *
    (2) Measure tire rolling resistance in newton per kilonewton as
specified in ISO 28580 (incorporated by reference in Sec.  1037.810),
except as specified in this paragraph (c). Use good engineering
judgment to ensure that your test results are not biased low. You may
ask us to identify a reference test laboratory to which you may
correlate your test results. Prior to beginning the test procedure in
Section 7 of ISO 28580 for a new bias-ply tire, perform a break-in
procedure by running the tire at the specified test speed, load, and
pressure for (60 2) minutes.
    (3) For each tire design tested, measure rolling resistance of at
least three different tires of that specific design and size. Perform
the test at least once for each tire. Calculate the arithmetic mean of
these results to the nearest 0.1 N/kN and use this value or any higher
value as your GEM input for TRRL. You must test at least one tire size
for each tire model, and may use engineering analysis to determine the
rolling resistance of other tire sizes of that model. Note that for
tire sizes that you do not test, we will treat your analytically
derived rolling resistances the same as test results, and we may
perform our own testing to verify your values. We may require you to
test a small sub-sample of untested tire sizes that we select.
* * * * *
    (f) Engine characteristics. Enter information from the engine
manufacturer to describe the installed engine and its operating
parameters as described in 40 CFR 1036.505. Note that you do not need
fuel consumption at idle for tractors.
* * * * *
    (h) * * *
    (1) For engines with no adjustable warm idle speed, input vehicle
idle speed as the manufacturer's declared warm idle speed. For engines
with adjustable warm idle speed, input your vehicle idle speed as
follows:

------------------------------------------------------------------------
                                                          Your default
     If your vehicle is a         And your engine is      vehicle idle
                                      subject to          speed is \a\
------------------------------------------------------------------------
(i) Heavy HDV.................  compression-ignition    600 r/min.
                                 or spark-ignition
                                 standards.
(ii) Medium HDV tractor.......  compression-ignition    700 r/min.
                                 standards.
(iii) Light HDV or Medium HDV   compression-ignition    750 r/min.
 vocational vehicle.             standards.
(iv) Light HDV or Medium HDV..  spark-ignition          600 r/min.
                                 standards.
------------------------------------------------------------------------
\a\ If the default idle speed is above or below the engine
  manufacturer's whole range of declared warm idle speeds, use the
  manufacturer's maximum or minimum declared warm idle speed,
  respectively, instead of the default value.

* * * * *

0
119. Amend Sec.  1037.534 by revising paragraph (d)(2) to read as
follows:

Sec.  1037.534  Constant-speed procedure for calculating drag area
(CdA).

* * * * *
    (d) * * *
    (2) Perform testing as described in paragraph (d)(3) of this
section over a sequence of test segments at constant vehicle speed as
follows:
    (i) (300 30) seconds in each direction at 10 mi/hr.
    (ii) (450 30) seconds in each direction at 70 mi/hr.
    (iii) (450 30) seconds in each direction at 50 mi/hr.
    (iv) (450 30) seconds in each direction at 70 mi/hr.
    (v) (450 30) seconds in each direction at 50 mi/hr.
    (vi) (300 30) seconds in each direction at 10 mi/hr.
* * * * *

0
120. Amend Sec.  1037.540 by revising the introductory text and
paragraphs (b)(3), (7), (8), and (f) to read as follows:

Sec.  1037.540  Special procedures for testing vehicles with hybrid
power take-off.

    This section describes optional procedures for quantifying the
reduction in greenhouse gas emissions for vehicles as a result of
running power take-off (PTO) devices with a hybrid energy delivery
system. See Sec.  1037.550 for powertrain testing requirements that
apply for drivetrain hybrid systems. The procedures are written to test
the PTO by ensuring that the engine produces all of the energy with no
net change in stored energy (charge-sustaining), and

for plug-in hybrid vehicles, also allowing for drawing down the stored
energy (charge-depleting). The full charge-sustaining test for the
hybrid vehicle is from a fully charged rechargeable energy storage
system (RESS) to a depleted RESS and then back to a fully charged RESS.
You must include all hardware for the PTO system. You may ask us to
modify the provisions of this section to allow testing hybrid vehicles
other than battery electric hybrids, consistent with good engineering
judgment. For plug-in hybrids, use a utility factor to properly weight
charge-sustaining and charge-depleting operation as described in
paragraph (f)(3) of this section.
* * * * *
    (b) * * *
    (3) Denormalize the PTO duty cycle in appendix B of this part using
the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.078

Where:

prefi = the reference pressure at each point i in the PTO
cycle.
pi = the normalized pressure at each point i in the PTO
cycle (relative to pmax).
pmax = the mean maximum pressure measured in paragraph (b)(2) of
this section.
pmin = the mean minimum pressure measured in paragraph (b)(2) of
this section.
* * * * *
    (7) Depending on the number of circuits the PTO system has, operate
the vehicle over one or concurrently over both of the denormalized PTO
duty cycles in appendix B of this part. Measure emissions during
operation over each duty cycle using the provisions of 40 CFR part
1066.
    (8) Measured pressures must meet the cycle-validation
specifications in the following table for each test run over the duty
cycle:

Table 1 to Paragraph (b)(8) of Sec.   1037.540--Statistical Criteria for
              Validating Each Test Run Over the Duty Cycle
------------------------------------------------------------------------
               Parameter \a\                          Pressure
------------------------------------------------------------------------
Slope, a1.................................  0.950 <=a1 <=1.030.
Absolute value of intercept,                <=2.0% of maximum mapped
 [verbar]a0[verbar].                         pressure.
Standard error of the estimate, SEE.......  <=10% of maximum mapped
                                             pressure.
Coefficient of determination, r2..........  >=0.970.
------------------------------------------------------------------------
\a\ Determine values for specified parameters as described in 40 CFR
  1065.514(e) by comparing measured values to denormalized pressure
  values from the duty cycle in appendix B of this part.

* * * * *
    (f) For Phase 2, calculate the delta PTO fuel results for input
into GEM during vehicle certification as follows:
    (1) Determine fuel consumption by calculating the mass of fuel for
each test in grams, mfuelPTO, without rounding, as described
in 40 CFR 1036.540(d)(12) for both the conventional vehicle and the
charge-sustaining and charge-depleting portions of the test for the
hybrid vehicle as applicable.
    (2) Divide the fuel mass by the applicable distance determined in
paragraph (d)(4) of this section and the appropriate standard payload
as defined in Sec.  1037.801 to determine the fuel-consumption rate in
g/ton-mile.
    (3) For plug-in hybrid electric vehicles calculate the utility
factor weighted fuel-consumption rate in g/ton-mile, as follows:
    (i) Determine the utility factor fraction for the PTO system from
the table in appendix E of this part using interpolation based on the
total time of the charge-depleting portion of the test as determined in
paragraphs (c)(6) and (d)(3) of this section.
    (ii) Weight the emissions from the charge-sustaining and charge-
depleting portions of the test to determine the utility factor-weighted
fuel mass, mfuelUF[cycle]plug-in, using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.079

Where:

i = an indexing variable that represents one test interval.
N = total number of charge-depleting test intervals.
mfuelPTOCD = total mass of fuel per ton-mile in the
charge-depleting portion of the test for each test interval, i,
starting from i = 1.
UFDCDi = utility factor fraction at time tCDi
as determined in paragraph (f)(3)(i) of this section for each test
interval, i, starting from i = 1.
j = an indexing variable that represents one test interval.
M = total number of charge-sustaining test intervals.
mfuelPTOCS = total mass of fuel per ton-mile in the
charge-sustaining portion of the test for each test interval, j,
starting from j = 1.
UFRCD = utility factor fraction at the full charge-
depleting time, tCD, as determined by interpolating the
approved utility factor curve. tCD is the sum of the time
over N charge-depleting test intervals.

    (4) Calculate the difference between the conventional PTO emissions
result and the hybrid PTO emissions result for input into GEM.
* * * * *

0
121. Revise Sec.  1037.550 to read as follows:

Sec.  1037.550  Powertrain testing.

    This section describes the procedure to measure fuel consumption
and create engine fuel maps by testing a powertrain that includes an
engine coupled with a transmission, drive axle, and hybrid components
or any assembly with one or more of those hardware elements. Engine
fuel maps are part of demonstrating compliance with Phase 2 vehicle
standards under this part; the powertrain test procedure in this
section is one option for generating this fuel-mapping information as
described in 40 CFR 1036.505. Additionally, this powertrain test
procedure is one option for certifying hybrids to the engine standards
in 40 CFR 1036.108.
    (a) General test provisions. The following provisions apply broadly
for testing under this section:
    (1) Measure NOX emissions as described in paragraph (k)
of this section. Include these measured NOX values any time
you report to us your greenhouse gas emissions or fuel consumption
values from testing under this section.
    (2) The procedures of 40 CFR part 1065 apply for testing in this
section except as specified. This section uses engine parameters and
variables that are consistent with 40 CFR part 1065.
    (3) Powertrain testing depends on models to calculate certain
parameters. You can use the detailed equations in this section to
create your own models, or use the GEM HIL model contained within GEM
Phase 2, Version 4.0 (incorporated by reference in Sec.  1037.810) to
simulate vehicle hardware elements as follows:
    (i) Create driveline and vehicle models that calculate the angular
speed

setpoint for the test cell dynamometer, fnref,dyno, based on
the torque measurement location. Use the detailed equations in
paragraph (f) of this section, the GEM HIL model's driveline and
vehicle submodels, or a combination of the equations and the submodels.
You may use the GEM HIL model's transmission submodel in paragraph (f)
of this section to simulate a transmission only if testing hybrid
engines.
    (ii) Create a driver model or use the GEM HIL model's driver
submodel to simulate a human driver modulating the throttle and brake
pedals to follow the test cycle as closely as possible.
    (iii) Create a cycle-interpolation model or use the GEM HIL model's
cycle submodel to interpolate the duty-cycles and feed the driver model
the duty-cycle reference vehicle speed for each point in the duty-
cycle.
    (4) The powertrain test procedure in this section is designed to
simulate operation of different vehicle configurations over specific
duty cycles. See paragraphs (h) and (j) of this section.
    (5) For each test run, record engine speed and torque as defined in
40 CFR 1065.915(d)(5) with a minimum sampling frequency of 1 Hz. These
engine speed and torque values represent a duty cycle that can be used
for separate testing with an engine mounted on an engine dynamometer
under Sec.  1037.551, such as for a selective enforcement audit as
described in Sec.  1037.301.
    (6) For hybrid powertrains with no plug-in capability, correct for
the net energy change of the energy storage device as described in 40
CFR 1066.501. For plug-in hybrid electric powertrains, follow 40 CFR
1066.501 to determine End-of-Test for charge-depleting operation. You
must get our approval in advance for your utility factor curve; we will
approve it if you can show that you created it, using good engineering
judgment, from sufficient in-use data of vehicles in the same
application as the vehicles in which the plug-in hybrid electric
powertrain will be installed. You may use methodologies described in
SAE J2841 (incorporated by reference in Sec.  1037.810) to develop the
utility factor curve.
    (7) The provisions related to carbon balance error verification in
40 CFR 1036.543 apply for all testing in this section. These procedures
are optional if you are only performing direct or indirect fuel-flow
measurement, but we will perform carbon balance error verification for
all testing under this section.
    (8) Do not apply accessory loads when conducting a powertrain test
to generate inputs to GEM if torque is measured at the axle input shaft
or wheel hubs.
    (9) If you test a powertrain over the duty cycle specified in 40
CFR 1036.514, control and apply the electrical accessory loads using
one of the following systems:
    (i) An alternator with dynamic electrical load control.
    (ii) A load bank connected directly to the powertrain's electrical
system.
    (b) Test configuration. Select a powertrain for testing as
described in Sec.  1037.235 or 40 CFR 1036.235 as applicable. Set up
the engine according to 40 CFR 1065.110 and 40 CFR 1065.405(b). Set the
engine's idle speed to idle speed defined in Sec.  1037.520(h)(1).
    (1) The default test configuration consists of a powertrain with
all components upstream of the axle. This involves connecting the
powertrain's output shaft directly to the dynamometer or to a gear box
with a fixed gear ratio and measuring torque at the axle input shaft.
You may instead set up the dynamometer to connect at the wheel hubs and
measure torque at that location. The preceeding sentence may apply if
your powertrain configuration requires it, such as for hybrid
powertrains or if you want to represent the axle performance with
powertrain test results.
    (2) For testing hybrid engines, connect the engine's crankshaft
directly to the dynamometer and measure torque at that location.
    (c) Powertrain temperatures during testing. Cool the powertrain
during testing so temperatures for oil, coolant, block, head,
transmission, battery, and power electronics are within the
manufacturer's expected ranges for normal operation. You may use
electronic control module outputs to comply with this paragraph (c).
You may use auxiliary coolers and fans.
    (d) Engine break in. Break in the engine according to 40 CFR
1065.405, the axle assembly according to Sec.  1037.560, and the
transmission according to Sec.  1037.565. You may instead break in the
powertrain as a complete system using the engine break in procedure in
40 CFR 1065.405.
    (e) Dynamometer setup. Set the dynamometer to operate in speed-
control mode (or torque-control mode for hybrid engine testing at idle,
including idle portions of transient duty cycles). Record data as
described in 40 CFR 1065.202. Command and control the dynamometer speed
at a minimum of 5 Hz, or 10 Hz for testing engine hybrids. Run the
vehicle model to calculate the dynamometer setpoints at a rate of at
least 100 Hz. If the dynamometer's command frequency is less than the
vehicle model dynamometer setpoint frequency, subsample the calculated
setpoints for commanding the dynamometer setpoints.
    (f) Driveline and vehicle model. Use the GEM HIL model's driveline
and vehicle submodels or the equations in this paragraph (f) to
calculate the dynamometer speed setpoint, fnref,dyno, based
on the torque measurement location. For all powertrains, configure GEM
with the accessory load set to zero. For hybrid engines, configure GEM
with the applicable accessory load as specified in 40 CFR 1036.505 and
1036.514. For all powertrains and hybrid engines, configure GEM with
the tire slip model disabled.
    (1) Driveline model with a transmission in hardware. For testing
with torque measurement at the axle input shaft or wheel hubs,
calculate, fnref,dyno, using the GEM HIL model's driveline
submodel or the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.080

Where:

ka[speed] = drive axle ratio as determined in paragraph
(h) of this section. Set ka[speed] equal to 1.0 if torque
is measured at the wheel hubs.
vrefi = simulated vehicle reference speed as calculated
in paragraph (f)(3) of this section.
r[speed] = tire radius as determined in paragraph (h) of
this section.

    (2) Driveline model with a simulated transmission. For testing with
the torque measurement at the engine's crankshaft,
fnref,dyno is the dynamometer target speed from the GEM HIL
model's transmission submodel. You may request our approval to change
the transmission submodel, as long as the changes do not affect the
gear selection logic. Before testing, initialize the transmission model
with the engine's measured torque curve and the applicable steady-state
fuel map from the GEM HIL model. You may request our approval to input
your own steady-state fuel map. For example, this request for approval
could include using a fuel map that represents the combined performance
of the engine and hybrid components. Configure the torque converter to
simulate neutral idle when using this procedure to generate engine fuel
maps in 40 CFR 1036.505 or to perform the Supplemental Emission Test
(SET) testing under 40 CFR

1036.510. You may change engine commanded torque at idle to better
represent CITT for transient testing under 40 CFR 1036.512. You may
change the simulated engine inertia to match the inertia of the engine
under test. We will evaluate your requests under this paragraph (f)(2)
based on your demonstration that that the adjusted testing better
represents in-use operation.
    (i) The transmission submodel needs the following model inputs:
    (A) Torque measured at the engine's crankshaft.
    (B) Engine estimated torque determined from the electronic control
module or by converting the instantaneous operator demand to an
instantaneous torque in N[middot]m.
    (C) Dynamometer mode when idling (speed-control or torque-control).
    (D) Measured engine speed when idling.
    (E) Transmission output angular speed,
fni,transmission, calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.081

Where:

ka[speed] = drive axle ratio as determined in paragraph
(h) of this section.
vrefi = simulated vehicle reference speed as calculated
in paragraph (f)(3) of this section.
r[speed] = tire radius as determined in paragraph (h) of
this section.

    (ii) The transmission submodel generates the following model
outputs:
    (A) Dynamometer target speed.
    (B) Dynamometer idle load.
    (C) Transmission engine load limit.
    (D) Engine speed target.
    (3) Vehicle model. Calculate the simulated vehicle reference speed,
[nu]refi, using the GEM HIL model's vehicle submodel or the
equations in this paragraph (f)(3):
[GRAPHIC] [TIFF OMITTED] TR24JA23.082

Where:

i = a time-based counter corresponding to each measurement during
the sampling period. Let vref1 = 0; start calculations at
i = 2. A 10-minute sampling period will generally involve 60,000
measurements.
T = instantaneous measured torque at the axle input, measured at the
wheel hubs, or simulated by the GEM HIL model's transmission
submodel.
Effaxle = axle efficiency. Use Effaxle = 0.955
for T >=0, and use Effaxle = \1/0\.955 for T <0. Use
Effaxle = 1.0 if torque is measured at the wheel hubs.
M = vehicle mass for a vehicle class as determined in paragraph (h)
of this section.
g = gravitational constant = 9.80665 m/s\2\.
Crr = coefficient of rolling resistance for a vehicle
class as determined in paragraph (h) of this section.
Gi -1 = the percent grade interpolated at
distance, D i-1, from the duty cycle in appendix D to
this part corresponding to measurement i-1.

[GRAPHIC] [TIFF OMITTED] TR24JA23.083

[rho] = air density at reference conditions. Use [rho] = 1.1845 kg/
m\3\.
CdA = drag area for a vehicle class as determined in
paragraph (h) of this section.
Fbrake,i-1 = instantaneous braking
force applied by the driver model.
[GRAPHIC] [TIFF OMITTED] TR24JA23.084

[Delta]t = the time interval between measurements. For example, at
100 Hz, [Delta]t = 0.0100 seconds.
Mrotating = inertial mass of rotating components. Let
Mrotating = 340 kg for vocational Light HDV or vocational
Medium HDV. See paragraph (h) of this section for tractors and for
vocational Heavy HDV.

    (4) Example. The following example illustrates a calculation of
fnref,dyno using paragraph (f)(1) of this section where
torque is measured at the axle input shaft. This example is for a
vocational Light HDV or vocational Medium HDV with 6 speed automatic
transmission at B speed (Test 4 in Table 1 to paragraph (h)(2)(ii) of
this section).

kaB = 4.0
rB = 0.399 m
T999 = 500.0 N[middot]m
Crr = 7.7 N/kN = 7.7[middot]10-\3\ N/N
M = 11408 kg
CdA = 5.4 m\2\
G999 = 0.39% = 0.0039
[GRAPHIC] [TIFF OMITTED] TR24JA23.085

Fbrake,999 = 0 N
vref,999 = 20.0 m/s
[Delta]t = 0.0100 s
Mrotating = 340 kg
[GRAPHIC] [TIFF OMITTED] TR24JA23.086

[GRAPHIC] [TIFF OMITTED] TR24JA23.087

    (g) Driver model. Use the GEM HIL model's driver submodel or design
a driver model to simulate a human driver modulating the throttle and
brake pedals. In either case, tune the model to follow the test cycle
as closely as possible meeting the following specifications:
    (1) The driver model must meet the following speed requirements:
    (i) For operation over the highway cruise cycles, the speed
requirements described in 40 CFR 1066.425(b) and (c).
    (ii) For operation over the transient cycle specified in appendix A
of this part, the SET as defined 40 CFR 1036.510, the Federal Test
Procedure (FTP) as defined in 40 CFR 1036.512, and the Low Load Cycle
(LLC) as defined in 40 CFR 1036.514, the speed requirements described
in 40 CFR 1066.425(b) and (c).
    (iii) The exceptions in 40 CFR 1066.425(b)(4) apply to the highway
cruise cycles, the transient cycle specified in appendix A of this
part, SET, FTP, and LLC.
    (iv) If the speeds do not conform to these criteria, the test is
not valid and must be repeated.
    (2) Send a brake signal when operator demand is zero and vehicle
speed is greater than the reference vehicle speed from the test cycle.
Include a delay before changing the brake signal to prevent dithering,
consistent with good engineering judgment.
    (3) Allow braking only if operator demand is zero.
    (4) Compensate for the distance driven over the duty cycle over the
course of the test. Use the following equation to perform the
compensation in real time to determine your time in the cycle:
[GRAPHIC] [TIFF OMITTED] TR24JA23.088

Where:

vvehicle = measured vehicle speed.
    vcycle = reference speed from the test cycle. If v
cycle,i -1 <1.0 m/s, set
vcycle,i-1 =
vvehicle,i-1.

    (h) Vehicle configurations to evaluate for generating fuel
maps as defined in 40 CFR 1036.505. Configure the driveline and vehicle
models from paragraph (f) of this section in the test cell to test the
powertrain. Simulate multiple vehicle configurations that represent the
range of intended vehicle applications using one of the following
options:
    (1) For known vehicle configurations, use at least three equally
spaced axle ratios or tire sizes and three different road loads (nine
configurations), or at least four equally spaced axle ratios or tire
sizes and two different road loads (eight configurations). Select axle
ratios to represent the full range of expected vehicle installations.
Select axle ratios and tire sizes such that the ratio of engine speed
to vehicle speed covers the range of ratios of minimum and maximum
engine speed to vehicle speed when the transmission is in top gear for
the vehicles in which the powertrain will be installed. Note that you
do not have to use the same axle ratios and tire sizes for each GEM
regulatory subcategory. You may determine appropriate
Crr, CdA, and mass values to cover the range of
intended vehicle applications or you may use the
Crr, CdA, and mass values specified in paragraph
(h)(2) of this section.
    (2) If vehicle configurations are not known, determine the vehicle
model inputs for a set of vehicle configurations as described in 40 CFR
1036.540(c)(3) with the following exceptions:
    (i) In the equations of 40 CFR 1036.540(c)(3)(i),
ktopgear is the actual top gear ratio of the powertrain
instead of the transmission gear ratio in the highest available gear
given in Table 1 in 40 CFR 1036.540.
    (ii) Test at least eight different vehicle configurations for
powertrains that will be installed in Spark-ignition HDE, vocational
Light HDV, and vocational Medium HDV using the following table instead
of Table 2 in 40 CFR 1036.540:

[GRAPHIC] [TIFF OMITTED] TR24JA23.089

    (iii) Select and test vehicle configurations as described in 40 CFR
1036.540(c)(3)(iii) for powertrains that will be installed in
vocational Heavy HDV and tractors using the following tables instead of
Table 3 and Table 4 in 40 CFR 1036.540:

[GRAPHIC] [TIFF OMITTED] TR24JA23.090

    (3) For hybrid powertrain systems where the transmission will be
simulated, use the transmission parameters defined in 40 CFR
1036.540(c)(2) to determine transmission type and gear ratio. Use a
fixed transmission efficiency of 0.95. The GEM HIL transmission model
uses a transmission parameter file for each test that includes the
transmission type, gear ratios, lockup gear, torque limit per gear from
40 CFR 1036.540(c)(2), and the values from 40 CFR 1036.505(b)(4) and
(c).
    (i) [Reserved]
    (j) Duty cycles to evaluate. Operate the powertrain over each of
the duty cycles specified in Sec.  1037.510(a)(2), and for each
applicable vehicle configuration from paragraph (h) of this section.
Determine cycle-average powertrain fuel maps by testing the powertrain
using the procedures in 40 CFR 1036.540(d) with the following
exceptions:
    (1) Understand ``engine'' to mean ``powertrain''.
    (2) Warm up the powertrain as described in 40 CFR 1036.520(c)(1).
    (3) Within 90 seconds after concluding the warm-up, start the
transition to the preconditioning cycle as described in paragraph
(j)(5) of this section.
    (4) For plug-in hybrid engines, precondition the battery and then
complete all back-to-back tests for each vehicle configuration
according to 40 CFR 1066.501 before moving to the next vehicle
configuration.
    (5) If the preceding duty cycle does not end at 0 mi/hr, transition
between duty cycles by decelerating at a rate of 2 mi/hr/s at 0% grade
until the vehicle reaches zero speed. Shut off the powertrain. Prepare
the powertrain and test cell for the next duty-cycle.
    (6) Start the next duty-cycle within 60 to 180 seconds after
shutting off the powertrain.
    (i) To start the next duty-cycle, for hybrid powertrains, key on
the vehicle and then start the duty-cycle. For conventional powertrains
key on the vehicle, start the engine, wait for the engine to stabilize
at idle speed, and then start the duty-cycle.
    (ii) If the duty-cycle does not start at 0 mi/hr, transition to the
next duty cycle by accelerating at a target rate of 1 mi/hr/s at 0%
grade. Stabilize for 10 seconds at the initial duty cycle conditions
and start the duty-cycle.
    (7) Calculate cycle work using GEM or the speed and torque from the
driveline and vehicle models from paragraph (f) of this section to
determine the sequence of duty cycles.
    (8) Calculate the mass of fuel consumed for idle duty cycles as

described in paragraph (n) of this section.
    (k) Measuring NOX emissions. Measure NOX
emissions for each sampling period in grams. You may perform these
measurements using a NOX emission-measurement system that
meets the requirements of 40 CFR part 1065, subpart J. If a system
malfunction prevents you from measuring NOX emissions during
a test under this section but the test otherwise gives valid results,
you may consider this a valid test and omit the NOX emission
measurements; however, we may require you to repeat the test if we
determine that you inappropriately voided the test with respect to
NOX emission measurement.
    (l) [Reserved]
    (m) Measured output speed validation. For each test point, validate
the measured output speed with the corresponding reference values. If
the range of reference speed is less than 10 percent of the mean
reference speed, you need to meet only the standard error of the
estimate in Table 1 of this section. You may delete points when the
vehicle is stopped. If your speed measurement is not at the location of
fnref, correct your measured speed using the constant speed
ratio between the two locations. Apply cycle-validation criteria for
each separate transient or highway cruise cycle based on the following
parameters:

  Table 4 to Paragraph (m) of Sec.   1037.550--Statistical Criteria for
                         Validating Duty Cycles
------------------------------------------------------------------------
               Parameter \a\                        Speed control
------------------------------------------------------------------------
Slope, a1.................................  0.990 <=a1 <=1.010.
Absolute value of intercept,                <=2.0% of maximum fnref
 [bond]a0[bond].                             speed.
Standard error of the estimate, SEE.......  <=2.0% of maximum fnref
                                             speed.
Coefficient of determination, r\2\........  >=0.990.
------------------------------------------------------------------------
\a\ Determine values for specified parameters as described in 40 CFR
  1065.514(e) by comparing measured and reference values for fnref,dyno.

    (n) Fuel consumption at idle. Record measurements using direct and/
or indirect measurement of fuel flow. Determine the fuel-consumption
rates at idle for the applicable duty cycles described in Sec.
1037.510(a)(2) as follows:
    (1) Direct fuel flow measurement. Determine the corresponding mean
values for mean idle fuel mass flow rate, mIfuelidle, for
each duty cycle, as applicable. Use of redundant direct fuel-flow
measurements require our advance approval.
    (2) Indirect fuel flow measurement. Record speed and torque and
measure emissions and other inputs needed to run the chemical balance
in 40 CFR 1065.655(c). Determine the corresponding mean values for each
duty cycle. Use of redundant indirect fuel-flow measurements require
our advance approval. Measure background concentration as described in
40 CFR 1036.535(b)(4)(ii). We recommend setting the CVS flow rate as
low as possible to minimize background, but without introducing errors
related to insufficient mixing or other operational considerations.
Note that for this testing 40 CFR 1065.140(e) does not apply, including
the minimum dilution ratio of 2:1 in the primary dilution stage.
Calculate the idle fuel mass flow rate for each duty cycle,
mIfuelidle, for each set of vehicle settings, as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.091

Where:

MC = molar mass of carbon.
wCmeas = carbon mass fraction of fuel (or mixture of test
fuels) as determined in 40 CFR 1065.655(d), except that you may not
use the default properties in Table 2 of 40 CFR 1065.655 to
determine [alpha], [beta], and wC for liquid fuels.
niexh = the mean raw exhaust molar flow rate from which
you measured emissions according to 40 CFR 1065.655.
xCcombdry = the mean concentration of carbon from fuel
and any injected fluids in the exhaust per mole of dry exhaust.
xH2Oexhdry = the mean concentration of
H2O in exhaust per mole of dry exhaust.
mICO2DEF = the mean CO2 mass
emission rate resulting from diesel exhaust fluid decomposition over
the duty cycle as determined in 40 CFR 1036.535(b)(9). If your
engine does not use diesel exhaust fluid, or if you choose not to
perform this correction, set miCO2DEF equal to
0.
MCO2 = molar mass of carbon dioxide.

Example:

MC = 12.0107 g/mol
wCmeas = 0.867
niexh = 25.534 mol/s
xCcombdry = 2.805[middot]10-\3\ mol/mol
xH2Oexhdry = 3.53[middot]10-\2\ mol/
mol
miCO2DEF = 0.0726 g/s
MCO2 = 44.0095
[GRAPHIC] [TIFF OMITTED] TR24JA23.092

mifuelidle = 0.405 g/s = 1458.6 g/hr
    (o) Create GEM inputs. Use the results of powertrain testing to
determine GEM inputs for the different simulated vehicle configurations
as follows:
    (1) Correct the measured or calculated fuel masses,
mfuel[cycle], and mean idle fuel mass flow rates,
mifuelidle, if applicable, for each test result to a mass-
specific net energy content of a reference fuel as described in 40 CFR
1036.535(e), replacing mifuel with mfuel[cycle]
where applicable in Eq. 1036.535-4.
    (2) Declare fuel masses, mfuel[cycle] and
mifuelidle. Determine mfuel[cycle] using the
calculated fuel mass consumption values described in 40 CFR
1036.540(d)(12). In addition, declare mean fuel mass flow rate for each
applicable idle duty cycle, mifuelidle. These declared
values may not be lower than any corresponding measured values
determined in this section. If you use both direct and indirect
measurement of fuel flow, determine the corresponding declared values
as described in 40 CFR 1036.535(g)(2) and (3). These declared values,
which serve as emission standards, collectively represent the
powertrain fuel map for certification.
    (3) For engines designed for plug-in hybrid electric vehicles, the
mass of fuel for each cycle, mfuel[cycle], is the utility
factor-weighted fuel mass, mfuelUF[cycle]. This is
determined by calculating mfuel for the full charge-
depleting and charge-sustaining portions of the test and

weighting the results, using the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.093

Where:

i = an indexing variable that represents one test interval.
N = total number of charge-depleting test intervals.
mfuel[cycle]CDi = total mass of fuel in the charge-
depleting portion of the test for each test interval, i, starting
from i = 1, including the test interval(s) from the transition
phase.
UFDCDi = utility factor fraction at distance
DCDi from Eq. 1037.505-9 as determined by interpolating
the approved utility factor curve for each test interval, i,
starting from i = 1. Let UFDCD0 = 0
j = an indexing variable that represents one test interval.
M = total number of charge-sustaining test intervals.
mfuel[cycle]CSj = total mass of fuel over the charge-
sustaining portion of the test for each test interval, j, starting
from j = 1.
UFRCD = utility factor fraction at the full charge-
depleting distance, RCD, as determined by interpolating
the approved utility factor curve. RCD is the cumulative
distance driven over N charge-depleting test intervals.
[GRAPHIC] [TIFF OMITTED] TR24JA23.094

Where:

k = an indexing variable that represents one recorded velocity
value.
Q = total number of measurements over the test interval.
v = vehicle velocity at each time step, k, starting from k = 1. For
tests completed under this section, v is the vehicle velocity as
determined by Eq. 1037.550-1. Note that this should include charge-
depleting test intervals that start when the engine is not yet
operating.
[Delta]t = 1/frecord
frecord = the record rate.

Example for the 55 mi/hr Cruise Cycle:

Q = 8790
v1 = 55.0 mi/hr
v2 = 55.0 mi/hr
v3 = 55.1 mi/hr
frecord = 10 Hz
[Delta]t = 1/10 Hz = 0.1 s
[GRAPHIC] [TIFF OMITTED] TR24JA23.095

DCD2 = 13.4 mi
DCD3 = 13.4 mi
N = 3
UFDCD1 = 0.05
UFDCD2 = 0.11
UFDCD3 = 0.21
mfuel55cruiseCD1 = 0 g
mfuel55cruiseCD2 = 0 g
mfuel55cruiseCD3 = 1675.4 g
M = 1
mfuel55cruiseCS = 4884.1 g
UFRCD = 0.21
[GRAPHIC] [TIFF OMITTED] TR24JA23.096

mfuelUF55cruise = 4026.0 g
    (4) For the transient cycle specified in Sec.  1037.510(a)(2)(i),
calculate powertrain output speed per unit of vehicle speed,
[GRAPHIC] [TIFF OMITTED] TR24JA23.097

using one of the following methods:
    (i) For testing with torque measurement at the axle input shaft:
    [GRAPHIC] [TIFF OMITTED] TR24JA23.098

Example:

ka = 4.0
rB = 0.399 m
[GRAPHIC] [TIFF OMITTED] TR24JA23.099

    (ii) For testing with torque measurement at the wheel hubs, use Eq.
1037.550-8 setting ka equal to 1.
    (iii) For testing with torque measurement at the engine's
crankshaft:
[GRAPHIC] [TIFF OMITTED] TR24JA23.100

Where:

fnengine = average engine speed when vehicle speed is at
or above 0.100 m/s.
vref = average simulated vehicle speed at or above 0.100
m/s.

Example:

fnengine = 1870 r/min = 31.17 r/s
vref = 19.06 m/s
[GRAPHIC] [TIFF OMITTED] TR24JA23.101

    (5) Calculate engine idle speed, by taking the average engine speed
measured during the transient cycle test while the vehicle speed is
below 0.100 m/s. (Note: Use all the charge-sustaining test intervals
when determining engine idle speed for plug-in hybrid engines and
powertrains.)
    (6) For the cruise cycles specified in Sec.  1037.510(a)(2)(ii),
calculate the average powertrain output speed, fnpowertrain,
and the average powertrain output torque (positive torque only),
Tpowertrain, at vehicle speed at or above 0.100 m/s. (Note:
Use all the charge-sustaining and charge-depleting test intervals when
determining fnpowertrain and Tpowertrain for
plug-in hybrid engines and powertrains.)
    (7) Calculate positive work, W[cycle], as the work over
the duty cycle at the axle input shaft, wheel hubs, or the engine's
crankshaft, as applicable, when vehicle speed is at or above 0.100 m/s.
For plug-in hybrids engines and powertrains, calculate,
W[cycle], by calculating the positive work over each of the
charge-sustaining and charge-depleting test intervals and then
averaging them together.
    (8) The following tables illustrate the GEM data inputs
corresponding to the different vehicle configurations for a given duty
cycle:
    (i) For the transient cycle:
    [GRAPHIC] [TIFF OMITTED] TR24JA23.102

    (ii) For the cruise cycles:

              Table 6 to Paragraph (o)(8)(ii) of Sec.   1037.550--Generic Example of Output Matrix for Cruise Cycle Vehicle Configurations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Configuration
             Parameter              --------------------------------------------------------------------------------------------------------------------
                                          1            2            3            4            5            6            7           ...           n
--------------------------------------------------------------------------------------------------------------------------------------------------------
mfuel[cycle].......................
fnpowertrain[cycle]................
Tpowertrain[cycle].................
W[cycle]...........................
--------------------------------------------------------------------------------------------------------------------------------------------------------

0
122. Amend Sec.  1037.551 by revising the introductory text and
paragraphs (b) and (c) to read as follows:

Sec.  1037.551  Engine-based simulation of powertrain testing.

    Section 1037.550 describes how to measure fuel consumption over
specific duty cycles with an engine coupled to a transmission; Sec.
1037.550(a)(5) describes how to create equivalent duty cycles for
repeating those same measurements with just the engine. This Sec.
1037.551 describes how to perform this engine testing to simulate the
powertrain test. These engine-based measurements may be used for
selective enforcement audits as described in Sec.  1037.301, as long as
the test engine's operation represents the engine operation observed in
the powertrain test. If we use this approach for confirmatory testing,
when making compliance determinations, we will consider the uncertainty
associated with this approach relative to full powertrain testing. Use
of this approach for engine SEAs is optional for engine manufacturers.
* * * * *
    (b) Operate the engine over the applicable engine duty cycles
corresponding to the vehicle cycles specified in Sec.  1037.510(a)(2)
for powertrain testing over the applicable vehicle simulations
described in Sec.  1037.550(j). Warm up the engine to prepare for the
transient test or one of the highway cruise cycles by operating it one
time over one of the simulations of the corresponding duty cycle. Warm
up the engine to prepare for the idle test by operating it over a
simulation of the 65-mi/hr highway cruise cycle for 600 seconds. Within
60 seconds after concluding the warm up cycle, start emission sampling
while the engine operates over the duty cycle. You may perform any
number of test runs directly in succession once the engine is warmed
up. Perform cycle validation as described in 40 CFR 1065.514 for engine
speed, torque, and power.
    (c) Calculate the mass of fuel consumed as described in Sec.
1037.550(n) and (o). Correct each measured value for the test fuel's
mass-specific net energy content as described in 40 CFR 1036.550. Use
these corrected values to determine whether the engine's emission
levels conform to the declared fuel-consumption rates from the
powertrain test.

0
123. Amend Sec.  1037.555 by revising the introductory text and
paragraph (g) to read as follows:

Sec.  1037.555  Special procedures for testing Phase 1 hybrid systems.

    This section describes a powertrain testing procedure for
simulating a chassis test with a pre-transmission or post-transmission
hybrid system to perform A to B testing of Phase 1 vehicles. These
procedures may also be used to perform A to B testing with non-hybrid
systems. See Sec.  1037.550 for Phase 2 hybrid systems.
* * * * *
    (g) The driver model should be designed to follow the cycle as
closely as possible and must meet the requirements of Sec.  1037.510
for steady-state testing and 40 CFR 1066.425 for transient testing. The
driver model should be designed so that the brake and throttle are not
applied at the same time.
* * * * *

0
124. Amend Sec.  1037.560 by revising paragraph (c) to read as follows:

Sec.  1037.560  Axle efficiency test.

* * * * *
    (c) Measure input and output speed and torque as described in 40
CFR 1065.210(b). You must use a speed-measurement system that meets an
accuracy of 0.05% of point. Use torque transducers that
meet an accuracy requirement of 1.0 N[middot]m for unloaded
test points and 0.2% of the maximum tested axle input
torque or output torque, respectively, for loaded test points.
Calibrate and verify measurement instruments according to 40 CFR part
1065, subpart D. Command speed and torque at a minimum of 10 Hz, and
record all data, including bulk oil temperature, at a minimum of 1 Hz
mean values.
* * * * *

0
125. Amend Sec.  1037.601 by revising paragraphs (a)(1) and (c) to read
as follows:

Sec.  1037.601  General compliance provisions.

    (a) * * *
    (1) Except as specifically allowed by this part or 40 CFR part
1068, it is a violation of 40 CFR 1068.101(a)(1) to introduce into U.S.
commerce either a tractor or vocational vehicle that is not certified
to the applicable requirements of this part or a tractor or vocational
vehicle containing an engine that is not certified to the applicable
requirements of 40 CFR part 86 or 1036. Further, it is a violation to
introduce into U.S. commerce a Phase 1 tractor containing an engine not
certified for use in tractors; or to introduce into U.S. commerce a
vocational vehicle containing a Light HDE or Medium HDE not certified
for use in vocational vehicles. These prohibitions apply especially to
the vehicle manufacturer. Note that this paragraph (a)(1) allows the
use of Heavy heavy-duty tractor engines in vocational vehicles.
* * * * *
    (c) The prohibitions of 40 CFR 1068.101 apply for vehicles subject
to the requirements of this part. The following specific provisions
apply:
    (1) The actions prohibited under this provision include introducing
into U.S. commerce a complete or incomplete vehicle subject to the
standards of this part where the vehicle is not covered by a valid
certificate of conformity or exemption.
    (2) Applying a Clean Idle sticker to a vehicles with an installed
engine that is not certified to the NOX standard of 40 CFR
1036.104(b) violates the prohibition in 40 CFR 1068.101(b)(7)(iii).
* * * * *

0
126. Amend Sec.  1037.605 by revising paragraphs (a) introductory text
and (a)(4) to read as follows:

Sec.  1037.605  Installing engines certified to alternate standards for
specialty vehicles.

    (a) General provisions. This section allows vehicle manufacturers
to introduce into U.S. commerce certain new motor vehicles using
engines certified to alternate emission standards specified in 40 CFR
1036.605 for motor vehicle engines used in specialty vehicles. You may
not install an engine certified to these alternate standards if there
is an engine certified to the full set of requirements of 40 CFR part
1036 that has the appropriate physical and performance characteristics
to power the vehicle. Note that, although these alternate emission
standards are mostly equivalent to standards that apply for nonroad
engines under 40 CFR part 1039 or 1048, they are specific to motor
vehicle engines. The provisions of this section apply for the following
types of specialty vehicles:
* * * * *
    (4) Through model year 2027, vehicles with a hybrid powertrain in
which the engine provides energy only for the Rechargeable Energy
Storage System.
* * * * *

0
127. Amend Sec.  1037.615 by revising paragraph (f) to read as follows:

Sec.  1037.615  Advanced technologies.

* * * * *
    (f) For electric vehicles and for fuel cells powered by hydrogen,
calculate CO2 credits using an FEL of 0 g/ton-mile. Note
that these vehicles are subject to compression-ignition standards for
CO2.
* * * * *

0
128. Amend Sec.  1037.635 by revising paragraph (b)(2) to read as
follows:

Sec.  1037.635  Glider kits and glider vehicles.

* * * * *
    (b) * * *
    (2) The engine must meet the criteria pollutant standards of 40 CFR
part 86 or 40 CFR part 1036 that apply for the engine model year
corresponding to the vehicle's date of manufacture.
* * * * *

0
129. Amend Sec.  1037.705 by revising paragraph (b) to read as follows:

Sec.  1037.705  Generating and calculating emission credits.

* * * * *
    (b) For each participating family or subfamily, calculate positive
or negative emission credits relative to the otherwise applicable
emission standard. Calculate positive emission credits for a family or
subfamily that has an FEL below the standard. Calculate negative
emission credits for a family or subfamily that has an FEL above the
standard. Sum your positive and negative credits for the model year
before rounding. Round the sum of emission credits to the nearest
megagram (Mg), using consistent units with the following equation:

Emission credits (Mg) = (Std-FEL) x PL x Volume x UL x 10
-\6\

Where:
Std = the emission standard associated with the specific regulatory
subcategory (g/ton-mile).
FEL = the family emission limit for the vehicle subfamily (g/ton-
mile).
PL = standard payload, in tons.
    Volume = U.S.-directed production volume of the vehicle
subfamily. For example, if you produce three configurations with the
same FEL, the subfamily production volume would be the sum of the
production volumes for these three configurations.
    UL = useful life of the vehicle, in miles, as described in
Sec. Sec.  1037.105 and 1037.106. Use 250,000 miles for trailers.
* * * * *

0
130. Amend Sec.  1037.725 by revising the section heading to read as
follows:

Sec.  1037.725  Required information for certification.

* * * * *

0
131. Amend Sec.  1037.730 by revising paragraphs (a), (b) introductory
text, (c), and (f) to read as follows:

Sec.  1037.730  ABT reports.

    (a) If you certify any vehicle families using the ABT provisions of
this subpart, send us a final report by September 30 following the end
of the model year.
    (b) Your report must include the following information for each
vehicle family participating in the ABT program:
* * * * *
    (c) Your report must include the following additional information:
    (1) Show that your net balance of emission credits from all your
participating vehicle families in each averaging set in the applicable
model year is not negative, except as allowed under Sec.  1037.745.
Your credit tracking must account for the limitation on credit life
under Sec.  1037.740(c).
    (2) State whether you will retain any emission credits for banking.
If you choose to retire emission credits that would otherwise be
eligible for banking, identify the families that generated the emission
credits, including the number of emission credits from each family.
    (3) State that the report's contents are accurate.
    (4) Identify the technologies that make up the certified
configuration associated with each vehicle identification number. You
may identify this as a range of identification numbers for vehicles
involving a single, identical certified configuration.
* * * * *
    (f) Correct errors in your report as follows:
    (1) If you or we determine by September 30 after the end of the
model year that errors mistakenly decreased your balance of emission
credits, you may correct the errors and recalculate the balance of
emission credits. You may not make these corrections for errors that
are determined later than September 30 after the end of the model year.
If you report a negative balance of emission credits, we may disallow
corrections under this paragraph (f)(1).
    (2) If you or we determine any time that errors mistakenly
increased your balance of emission credits, you must correct the errors
and recalculate the balance of emission credits.

0
132. Amend Sec.  1037.735 by revising paragraph (b) to read as follows:

Sec.  1037.735  Recordkeeping.

* * * * *
    (b) Keep the records required by this section for at least eight
years after the due date for the final report. You may not use emission
credits for any vehicles if you do not keep all the records required
under this section. You must therefore keep these records to continue
to bank valid credits.
* * * * *

0
133. Amend Sec.  1037.740 by revising paragraph (b) to read as follows:

Sec.  1037.740  Restrictions for using emission credits.

* * * * *
    (b) Credits from hybrid vehicles and other advanced technologies.
The following provisions apply for credits you generate under Sec.
1037.615.
    (1) Credits generated from Phase 1 vehicles may be used for any of
the averaging sets identified in paragraph (a) of this section; you may
also use those credits to demonstrate compliance with the
CO2 emission standards in 40 CFR 86.1819 and 40 CFR part
1036. Similarly, you may use Phase 1 advanced-technology credits
generated under 40 CFR 86.1819-14(k)(7) or 40 CFR 1036.615 to
demonstrate compliance with the CO2 standards in this part.
The maximum amount of advanced-technology credits generated from Phase
1 vehicles that you may bring into each of the following service class
groups is 60,000 Mg per model year:
    (i) Spark-ignition HDE, Light HDE, and Light HDV. This group
comprises the averaging set listed in paragraph (a)(1) of this section
and the averaging set listed in 40 CFR 1036.740(a)(1) and (2).
    (ii) Medium HDE and Medium HDV. This group comprises the averaging
sets listed in paragraph (a)(2) of this section and 40 CFR
1036.740(a)(3).
    (iii) Heavy HDE and Heavy HDV. This group comprises the averaging
sets listed in paragraph (a)(3) of this section and 40 CFR
1036.740(a)(4).
    (iv) This paragraph (b)(1) does not limit the advanced-technology
credits that can be used within a service class group if they were
generated in that same service class group.
    (2) Credits generated from Phase 2 vehicles are subject to all the
averaging-set restrictions that apply to other emission credits.
* * * * *

0
134. Amend Sec.  1037.801 by:
0
a. Revising the definitions of ``Adjustable parameter'', ``Automatic
tire inflation system'', and ``Automatic transmission (AT)'';
0
b. Adding definitions of ``Charge-depleting'', and ``Charge-
sustaining'' in alphabetical order;
0
c. Revising the definitions of ``Designated Compliance Officer'' and of
``Electric vehicle'';
0
d. Adding a definition of ``Emission-related component'' in
alphabetical order; and
0
e. Revising the definitions of ``Low rolling resistance tire'',
``Neutral coasting'', ``Rechargeable Energy Storage System (RESS)'',
and ``Tire rolling resistance level (TRRL)''.
    The additions and revisions read as follows:

Sec.  1037.801  Definitions.

* * * * *
    Adjustable parameter has the meaning given in 40 CFR 1068.30.
* * * * *
    Automatic tire inflation system means a pneumatically or
electronically activated system installed on a vehicle to maintain tire
pressure at a preset level. These systems eliminate the need to
manually inflate tires. Note that this is different than a tire
pressure monitoring system, which we define separately in this section.
    Automatic transmission (AT) means a transmission with a torque
converter (or equivalent) that uses computerize or other internal
controls to shift gears in response to a single driver input for
controlling vehicle speed.. Note that automatic manual transmissions
are not automatic transmissions because they do not include torque
converters.
* * * * *
    Charge-depleting has the meaning given in 40 CFR 1066.1001.
    Charge-sustaining has the meaning given in 40 CFR 1066.1001.
* * * * *
    Designated Compliance Officer means one of the following:
    (1) For compression-ignition engines, Designated Compliance Officer
means Director, Diesel Engine Compliance Center, U.S. Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
[email protected]; www.epa.gov/ve-certification.
    (2) For spark-ignition engines, Designated Compliance Officer means
Director, Gasoline Engine Compliance Center, U.S. Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
[email protected]; www.epa.gov/ve-certification.
* * * * *
    Electric vehicle means a motor vehicle that does not include an
engine, and is powered solely by an external source of electricity and/
or solar power. Note that this definition does not include hybrid
electric vehicles or fuel cell vehicles that use a chemical fuel such
as gasoline, diesel fuel, or hydrogen. Electric vehicles may also be
referred to as all-electric vehicles to distinguish them from hybrid
vehicles.
* * * * *
    Emission-related component has the meaning given in 40 CFR part
1068, appendix A.
* * * * *
    Low rolling resistance tire means a tire on a vocational vehicle
with a TRRL at or below of 7.7 N/kN, a steer tire on a tractor with a
TRRL at or below 7.7 N/kN, a drive tire on a tractor with a TRRL at or
below 8.1 N/kN, a tire on a non-box trailer with a TRRL at or below of
6.5 N/kN, or a tire on a box van with a TRRL at or below of 6.0 N/kN.
* * * * *
    Neutral coasting means a vehicle technology that automatically puts
the transmission in neutral when the vehicle has minimal power demand
while in motion, such as driving downhill.
* * * * *
    Rechargeable Energy Storage System (RESS) has the meaning given in
40 CFR 1065.1001.
* * * * *
    Tire rolling resistance level (TRRL) means a value with units of N/
kN that represents the rolling resistance of a tire configuration.
TRRLs are used as modeling inputs under Sec. Sec.  1037.515 and
1037.520. Note that a manufacturer may use the measured value for a
tire configuration's coefficient of rolling resistance, or assign some
higher value.
* * * * *

0
135. Amend Sec.  1037.805 by revising paragraphs (a), (b), (d), (e),
(f), and (g) to read as follows:

Sec.  1037.805  Symbols, abbreviations, and acronyms.

* * * * *
    (a) Symbols for chemical species. This part uses the following
symbols for chemical species and exhaust constituents:

    Table 1 to Paragraph (a) of Sec.   1037.805--Symbols for Chemical
                    Species and Exhaust Constituents
------------------------------------------------------------------------
                  Symbol                               Species
------------------------------------------------------------------------
C.........................................  carbon.
CH4.......................................  methane.
CO........................................  carbon monoxide.
CO2.......................................  carbon dioxide.
H2O.......................................  water.
HC........................................  hydrocarbon.
NMHC......................................  nonmethane hydrocarbon.
NMHCE.....................................  nonmethane hydrocarbon
                                             equivalent.
NO........................................  nitric oxide.
NO2.......................................  nitrogen dioxide.
NOX.......................................  oxides of nitrogen.
N2O.......................................  nitrous oxide.
PM........................................  particulate matter.
THC.......................................  total hydrocarbon.
THCE......................................  total hydrocarbon
                                             equivalent.
------------------------------------------------------------------------

    (b) Symbols for quantities. This part 1037 uses the following
symbols and units of measure for various quantities:

                       Table 2 to Paragraph (b) of Sec.   1037.805--Symbols for Quantities
----------------------------------------------------------------------------------------------------------------
                                                                                Unit in terms of SI base
      Symbol             Quantity             Unit                 Unit symbol                    units
----------------------------------------------------------------------------------------------------------------
A.................  vehicle            pound force or     lbf or N....................  kg[middot]m[middot]s-
                     frictional load.   newton.                                          \2\.
a.................  axle position
                     regression
                     coefficient.
[alpha]...........  atomic hydrogen-   mole per mole....  mol/mol.....................  1.
                     to-carbon ratio.
[alpha]...........  axle position
                     regression
                     coefficient.
[alpha]0..........  intercept of air
                     speed correction.
[alpha]1..........  slope of air
                     speed correction.
ag................  acceleration of    meters per second  m/s\2\......................  m[middot]s-\2\.
                     Earth's gravity.   squared.
a0................  intercept of
                     least squares
                     regression.
a1................  slope of least
                     squares
                     regression.
B.................  vehicle load from  pound force per    lbf/(mi/hr) or N[middot]s/m.  kg[middot]s-\1\.
                     drag and rolling   mile per hour or
                     resistance.        newton second
                                        per meter.
b.................  axle position
                     regression
                     coefficient.
[beta]............  atomic oxygen-to-  mole per mole....  mol/mol.....................  1.
                     carbon ratio.
[beta]............  axle position
                     regression
                     coefficient.
[beta]0...........  intercept of air
                     direction
                     correction.
[beta]1...........  slope of air
                     direction
                     correction.
C.................  vehicle-specific   pound force per    lbf/mph\2\ or N[middot]s\2\/  kg[middot]m-\1\.
                     aerodynamic        mile per hour      m\2\.
                     effects.           squared or
                                        newton-second
                                        squared per
                                        meter squared.
c.................  axle position
                     regression
                     coefficient.

ci................  axle test
                     regression
                     coefficients.
Ci................  constant.........
[Delta]CdA........  differential drag  meter squared....  m\2\........................  m\2\.
                     area.
CdA...............  drag area........  meter squared....  m\2\........................  m\2\.
Cd................  drag coefficient.
CF................  correction factor
Crr...............  coefficient of     newton per         N/kN........................  10-\3\.
                     rolling            kilonewton.
                     resistance.
D.................  distance.........  miles or meters..  mi or m.....................  m.
e.................  mass-weighted      grams per ton-     g/ton-mi....................  g/kg-km.
                     emission result.   mile.
Eff...............  efficiency.......
F.................  adjustment factor
F.................  force............  pound force or     lbf or N....................  kg[middot]m[middot]s-
                                        newton.                                          \2\.
fn................  angular speed      revolutions per    r/min.......................  [pi][middot]30[middot]s-
                     (shaft).           minute.                                          \1\.
G.................  road grade.......  percent..........  %...........................  10-\2\.
g.................  gravitational      meters per second  m/s\2\......................  m[middot]s-\2\.
                     acceleration.      squared.
h.................  elevation or       meters...........  m...........................  m.
                     height.
i.................  indexing variable
ka................  drive axle ratio.  .................  ............................  1.
kd................  transmission gear
                     ratio.
ktopgear..........  highest available
                     transmission
                     gear.
L.................  load over axle...  pound force or     lbf or N....................  kg[middot]m[middot]s-
                                        newton.                                          \2\.
m.................  mass.............  pound mass or      lbm or kg...................  kg.
                                        kilogram.
M.................  molar mass.......  gram per mole....  g/mol.......................  10-
                                                                                \3\[middot]kg[middot]mo
                                                                                l-\1\.
M.................  vehicle mass.....  kilogram.........  kg..........................  kg.
Me................  vehicle effective  kilogram.........  kg..........................  kg.
                     mass.
Mrotating.........  inertial mass of   kilogram.........  kg..........................  kg.
                     rotating
                     components.
N.................  total number in
                     series.
n.................  number of tires..
n.................  amount of          mole per second..  mol/s.......................  mol[middot]s-\1\.
                     substance rate.
P.................  power............  kilowatt.........  kW..........................  10\3\[middot]m\2\[middot
                                                                                ]kg[middot]s-\3\.
p.................  pressure.........  pascal...........  Pa..........................  kg[middot]m-\1\[middot]s-
                                                                                \2\.
[rho].............  mass density.....  kilogram per       kg/m\3\.....................  kg[middot]m-\3\.
                                        cubic meter.
PL................  payload..........  tons.............  ton.........................  kg.
[phis]............  direction........  degrees..........  [deg].......................  [deg].
[psi].............  direction........  degrees..........  [deg].......................  [deg].
r.................  tire radius......  meter............  m...........................  m.
r\2\..............  coefficient of
                     determination.
Re ..............  Reynolds number..
SEE...............  standard error of
                     the estimate.
[sigma]...........  standard
                     deviation.
TRPM..............  tire revolutions   revolutions per    r/mi........................
                     per mile.          mile.
TRRL..............  tire rolling       newton per         N/kN........................  10-\3\.
                     resistance level.  kilonewton.
T.................  absolute           kelvin...........  K...........................  K.
                     temperature.
T.................  Celsius            degree Celsius...  [deg]C......................  K-273.15.
                     temperature.
T.................  torque (moment of  newton meter.....  N[middot]m..................  m\2\[middot]kg[middot]s-
                     force).                                                             \2\.
t.................  time.............  hour or second...  hr or s.....................  s.
[Delta]t..........  time interval,     second...........  s...........................  s.
                     period, 1/
                     frequency.
UF................  utility factor...
v.................  speed............  miles per hour or  mi/hr or m/s................  m[middot]s-\1\.
                                        meters per
                                        second.
w.................  weighting factor.
w.................  wind speed.......  miles per hour...  mi/hr.......................  m[middot]s-\1\.
W.................  work.............  kilowatt-hour....  kW[middot]hr................  3.6[middot]m\2\[middot]k
                                                                                g[middot]s-\1\.
wC................  carbon mass        gram per gram....  g/g.........................  1.
                     fraction.
WR................  weight reduction.  pound mass.......  lbm.........................  kg.
x.................  amount of          mole per mole....  mol/mol.....................  1.
                     substance mole
                     fraction.
----------------------------------------------------------------------------------------------------------------

* * * * *
    (d) Subscripts. This part uses the following subscripts for
modifying quantity symbols:

         Table 4 to Paragraph (d) of Sec.   1037.805--Subscripts
------------------------------------------------------------------------
               Subscript                             Meaning
------------------------------------------------------------------------
6..........................  6[deg] yaw angle
                                          sweep.
A......................................  A speed.
air....................................  air.
aero...................................  aerodynamic.

alt....................................  alternative.
act....................................  actual or measured condition.
air....................................  air.
axle...................................  axle.
B......................................  B speed.
brake..................................  brake.
C......................................  C speed.
Ccombdry...............................  carbon from fuel per mole of
                                          dry exhaust.
CD.....................................  charge-depleting.
circuit................................  circuit.
CO2DEF.................................  CO2 resulting from diesel
                                          exhaust fluid decomposition.
CO2PTO.................................  CO2 emissions for PTO cycle.
coastdown..............................  coastdown.
comp...................................  composite.
CS.....................................  charge-sustaining.
cycle..................................  test cycle.
drive..................................  drive axle.
drive-idle.............................  idle with the transmission in
                                          drive.
driver.................................  driver.
dyno...................................  dynamometer.
effective..............................  effective.
end....................................  end.
eng....................................  engine.
event..................................  event.
fuel...................................  fuel.
full...................................  full.
grade..................................  grade.
H2Oexhaustdry..........................  H2O in exhaust per mole of
                                          exhaust.
hi.....................................  high.
i......................................  an individual of a series.
idle...................................  idle.
in.....................................  inlet.
inc....................................  increment.
lo.....................................  low.
loss...................................  loss.
max....................................  maximum.
meas...................................  measured quantity.
med....................................  median.
min....................................  minimum.
moving.................................  moving.
out....................................  outlet.
P......................................  power.
pair...................................  pair of speed segments.
parked-idle............................  idle with the transmission in
                                          park.
partial................................  partial.
ploss..................................  power loss.
plug-in................................  plug-in hybrid electric
                                          vehicle.
powertrain.............................  powertrain.
PTO....................................  power take-off.
rated..................................  rated speed.
record.................................  record.
ref....................................  reference quantity.
RL.....................................  road load.
rotating...............................  rotating.
seg....................................  segment.
speed..................................  speed.
spin...................................  axle spin loss.
start..................................  start.
steer..................................  steer axle.
t......................................  tire.
test...................................  test.
th.....................................  theoretical.
total..................................  total.
trac...................................  traction.
trac10.................................  traction force at 10 mi/hr.
trailer................................  trailer axle.
transient..............................  transient.
TRR....................................  tire rolling resistance.
UF.....................................  utility factor.
urea...................................  urea.
veh....................................  vehicle.
w......................................  wind.

wa.....................................  wind average.
yaw....................................  yaw angle.
ys.....................................  yaw sweep.
zero...................................  zero quantity.
------------------------------------------------------------------------

    (e) Other acronyms and abbreviations. This part uses the following
additional abbreviations and acronyms:

     Table 5 to Paragraph (e) of Sec.   1037.805--Other Acronyms and
                              Abbreviations
------------------------------------------------------------------------
                Acronym                              Meaning
------------------------------------------------------------------------
ABT....................................  averaging, banking, and
                                          trading.
AECD...................................  auxiliary emission control
                                          device.
AES....................................  automatic engine shutdown.
APU....................................  auxiliary power unit.
CD.....................................  charge-depleting.
CFD....................................  computational fluid dynamics.
CFR....................................  Code of Federal Regulations.
CITT...................................  curb idle transmission torque.
CS.....................................  charge-sustaining.
DOT....................................  Department of Transportation.
ECM....................................  electronic control module.
EPA....................................  Environmental Protection
                                          Agency.
FE.....................................  fuel economy.
FEL....................................  Family Emission Limit.
FTP....................................  Federal Test Procedure.
GAWR...................................  gross axle weight rating.
GCWR...................................  gross combination weight
                                          rating.
GEM....................................  greenhouse gas emission model.