Medium HDV..........................                                                       234                                                       225
Heavy HDV...........................                                                       226                                                       222
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *
    (h) * * *
    (1) The following alternative emission standards apply by vehicle
type and model year as follows:

     Table 5 of Paragraph (h)(1) of Sec.   1037.105--Optional Phase 3 CO2 Standards for Model Year 2027 and Later Custom Chassis Vocational Vehicles
                                                                      [g/ton-mile]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Model year      Model year      Model year      Model year      Model year      Model year
          Optional custom chassis vehicle type                 2027            2028            2029            2030            2031       2032 and later
--------------------------------------------------------------------------------------------------------------------------------------------------------
School Bus..............................................             190             182             176             168             163             149
Other Bus...............................................             286             269             255             237             220             189
Coach Bus...............................................             205             205             205             185             164             154
Refuse Hauler...........................................             253             241             232             221             212             191
Concrete Mixer..........................................             259             250             240             231             224             205
Motor home..............................................             226             226             226             226             226             226
Mixed-use vehicle.......................................             316             316             316             316             316             316
Emergency vehicle.......................................             319             319             319             319             319             319
--------------------------------------------------------------------------------------------------------------------------------------------------------

 Table 6 of Paragraph (h)(1) of Sec.   1037.105--Phase 2 Custom Chassis
               Standards for Model Years 2021 Through 2026
                              [g/ton-mile]
------------------------------------------------------------------------
                                      Assigned vehicle      Model year
         Vehicle type \a\               service class        2021-2026
------------------------------------------------------------------------
School bus........................  Medium HDV..........             291
Motor home........................  Medium HDV..........             228
Coach bus.........................  Heavy HDV...........             210
Other bus.........................  Heavy HDV...........             300
Refuse hauler.....................  Heavy HDV...........             313
Concrete mixer....................  Heavy HDV...........             319
Mixed-use vehicle.................  Heavy HDV...........             319
Emergency vehicle.................  Heavy HDV...........             324
------------------------------------------------------------------------
\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).

* * * * *
0
48. Amend Sec.  1037.106 by revising the section heading and paragraph
(b), removing and reserving paragraph (c), and revising paragraphs
(f)(2) introductory text and (f)(2)(i) to read as follows:

Sec.  1037.106  CO2 emission standards for tractors above
26,000 pounds GVWR.

* * * * *
    (b) CO2 standards in this paragraph (b) apply based on
modeling and testing as described in subpart F of this part. The
provisions of Sec.  1037.241 specify how to comply with these
standards.
    (1) Model year 2027 and later tractors are subject to
CO2 standards corresponding to the selected subcategories as
shown in the following tables:

  Table 1 of Paragraph (b)(1) of Sec.   1037.106--CO2 Emission Standards for Model Year 2027 and Later Tractors
                                                  [g/ton-mile]
----------------------------------------------------------------------------------------------------------------
                                                    Class 7 all    Class 8  day       Class 8
         Model year               Roof height       cab styles          cab         sleeper cab     Heavy-haul
----------------------------------------------------------------------------------------------------------------
2027........................  Low...............            86.6            66.1            64.1            48.3
                              Mid...............            93.1            70.2            69.6
                              High..............            90.0            68.1            64.3
2028........................  Low...............            84.7            64.6            64.1            48.3
                              Mid...............            91.0            68.6            69.6
                              High..............            88.0            66.6            64.3
2029........................  Low...............            81.8            62.4            64.1            48.3
                              Mid...............            87.9            66.3            69.6
                              High..............            85.0            64.3            64.3
2030........................  Low...............            77.0            58.7            57.7            43.0
                              Mid...............            82.7            62.4            62.6
                              High..............            80.0            60.6            57.9
2031........................  Low...............            67.3            51.4            51.3            42.5
                              Mid...............            72.4            54.6            55.7
                              High..............            70.0            53.0            51.4
2032 and later..............  Low...............            63.5            48.4            48.1            41.1
                              Mid...............            68.2            51.5            52.2

                              High..............            66.0            50.0            48.2
----------------------------------------------------------------------------------------------------------------

    (2) Model year 2026 and earlier tractors are subject to
CO2 standards corresponding to the selected subcategory as
shown in the following table:

     Table 2 of Paragraph (b)(2) of Sec.   1037.106--CO2 Standards for Model Year 2026 and Earlier Tractors
                                                  [g/ton-mile]
----------------------------------------------------------------------------------------------------------------
                                                      Phase 1         Phase 1         Phase 2         Phase 2
                                                   standards for   standards for   standards for   standards for
                 Subcategory \a\                    model years     model years     model years     model years
                                                     2014-2016       2017-2020       2021-2023       2024-2026
----------------------------------------------------------------------------------------------------------------
Class 7 Low-Roof (all cab styles)...............             107             104           105.5            99.8
Class 7 Mid-Roof (all cab styles)...............             119             115           113.2           107.1
Class 7 High-Roof (all cab styles)..............             124             120           113.5           106.6
Class 8 Low-Roof Day Cab........................              81              80            80.5            76.2
Class 8 Low-Roof Sleeper Cab....................              68              66            72.3            68.0
Class 8 Mid-Roof Day Cab........................              88              86            85.4            80.9
Class 8 Mid-Roof Sleeper Cab....................              76              73            78.0            73.5
Class 8 High-Roof Day Cab.......................              92              89            85.6            80.4
Class 8 High-Roof Sleeper Cab...................              75              72            75.7            70.7
Heavy-Haul Tractors.............................  ..............  ..............            52.4            50.2
----------------------------------------------------------------------------------------------------------------

* * * * *
    (f) * * *
    (2) You may optionally certify Class 7 tractors not covered by
paragraph (f)(1) of this section to the standards and useful life for
Class 8 tractors. This paragraph (f)(2) applies equally for hybrid
vehicles, battery electric vehicles, and fuel cell electric vehicles.
Credit provisions apply as follows:
    (i) If you certify all your Class 7 tractors to Class 8 standards,
you may use these Heavy HDV credits without restriction.
* * * * *

Sec.  1037.107  [Removed]

0
49. Remove Sec.  1037.107.
0
50. Amend Sec.  1037.115 by revising paragraphs (a) and (e)(1) and
adding paragraph (f) 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 are deemed not to be adjustable parameters.
* * * * *
    (e) * * *
    (1) This paragraph (e) is intended to address air conditioning
systems for which the primary purpose is to cool the driver
compartment. This would generally include all cab-complete pickups and
vans. Similarly, it does not apply for self-contained air conditioning
used to cool passengers or refrigeration units used to cool cargo on
vocational vehicles. For purposes of this paragraph (e), a self-
contained system is an enclosed unit with its own evaporator and
condenser even if it draws power from the engine.
* * * * *
    (f) Battery durability monitor. Battery electric vehicles and plug-
in hybrid electric vehicles must meet monitoring requirements related
to batteries serving as a Rechargeable Energy Storage System from GTR
No. 22 (incorporated by reference, see Sec.  1037.810). The
requirements of this section apply starting in model year 2030. The
following clarifications and adjustments to GTR No. 22 apply for
vehicles subject to this section:
    (1) Install a customer-accessible display that monitors, estimates,
and communicates the vehicle's State of Certified Energy (SOCE) include
information in the application for certification as described in Sec.
1037.205. Monitoring requirements related to State of Certified Range
(SOCR) do not apply.
    (2) Accuracy requirements for SOCE in GTR No. 22 do not apply.
Minimum Performance Requirements for battery durability also do not
apply.
    (3) For battery electric vehicles, use good engineering judgment to
develop a test procedure for determining useable battery energy (UBE).
    (4) For plug-hybrid electric vehicles, determine UBE as described
in 40 CFR 1036.545.
0
51. Amend Sec.  1037.120 by:
0
a. Revising paragraph (b)(1)(iii).
0
b. Removing paragraph (b)(1)(iv).
0
c. Revising paragraph (c).
    The revisions read as follows:

Sec.  1037.120  Emission-related warranty requirements.

* * * * *
    (b) * * *
    (1) * * *
    (iii) 2 years or 24,000 miles for tires.
* * * * *
    (c) Components covered. The emission-related warranty covers tires,
automatic tire inflation systems, tire pressure monitoring systems,
vehicle

speed limiters, idle-reduction systems, 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),
fuel cell stacks, and RESS and other components used with hybrid
systems, battery electric vehicles, and fuel cell electric vehicles 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, and any other
components whose failure would increase a vehicle's CO2
emissions. 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.
* * * * *
0
52. Amend Sec.  1037.130 by revising paragraph (a) to read as follows:

Sec.  1037.130  Assembly instructions for secondary vehicle
manufacturers.

    (a) If you sell a certified incomplete vehicle to a secondary
vehicle manufacturer, give the secondary vehicle manufacturer
instructions for completing vehicle assembly consistent with the
requirements of this part. Include all information necessary to ensure
that the final vehicle assembly (including the engine) will be in its
certified configuration.
* * * * *
0
53. Amend Sec.  1037.140 by revising paragraph (g)(5) introductory text
to read as follows:

Sec.  1037.140  Classifying vehicles and determining vehicle
parameters.

* * * * *
    (g) * * *
    (5) Heavy-duty vehicles with no installed propulsion engine, such
as battery electric vehicles, are divided as follows:
* * * * *
0
54. Amend Sec.  1037.150 by:
0
a. Revising paragraphs (c), (f) and (p);
0
b. Removing paragraphs (u) through (x);
0
c. Redesignating paragraphs (y) through (bb) as paragraphs (u) through
(x);
0
d. Revising newly redesignated paragraph (x); and
0
e. Adding a new paragraph (y).
    The revisions and addition read as follows:

Sec.  1037.150  Interim provisions.

* * * * *
    (c) Small manufacturers. The following provisions apply for small
manufacturers:
    (1) The following provisions apply through model year 2026:
    (i) The greenhouse gas standards of Sec. Sec.  1037.105 and
1037.106 are optional for small manufacturers producing vehicles with a
date of manufacture before January 1, 2022. In addition, small
manufacturers producing vehicles that run on any fuel other than
gasoline, E85, or diesel fuel may delay complying with every later
standard under this part by one model year.
    (ii) Qualifying manufacturers must notify the Designated Compliance
Officer each model year before introducing excluded vehicles into U.S.
commerce. This notification must include a description of the
manufacturer's qualification as a small business under 13 CFR 121.201.
Manufacturers must label excluded vehicles with the following
statement: ``THIS VEHICLE IS EXCLUDED UNDER 40 CFR 1037.150(c).''
    (iii) Small manufacturers may meet Phase 1 standards instead of
Phase 2 standards in the first year Phase 2 standards apply to them if
they voluntarily comply with the Phase 1 standards for the full
preceding year. Specifically, small manufacturers may certify their
model year 2022 vehicles to the Phase 1 greenhouse gas standards of
Sec. Sec.  1037.105 and 1037.106 if they certify all the vehicles from
their annual production volume included in emission credit calculations
for the Phase 1 standards starting on or before January 1, 2021.
    (2) The following provisions apply for model year 2027 and later
for qualifying small manufacturers:
    (i) The following standards apply for vocational vehicles instead
of the standards specified in Sec.  1037.105:

     Table 1 of Paragraph (c)(2)(i) of Sec.   1037.150--Small Manufacturer CO2 Standards Vocational Vehicles
                                                  [g/ton-mile]
----------------------------------------------------------------------------------------------------------------
             Engine cycle                     Vehicle size         Multi-purpose     Regional          Urban
----------------------------------------------------------------------------------------------------------------
Compression-ignition..................  Light HDV...............             330             291             367
Compression-ignition..................  Medium HDV..............             235             218             258
Compression-ignition..................  Heavy HDV...............             230             189             269
Spark-ignition........................  Light HDV...............             372             319             413
Spark-ignition........................  Medium HDV..............             268             247             297
----------------------------------------------------------------------------------------------------------------

  Table 2 of Paragraph (c)(2)(i) of Sec.   1037.150--Small Manufacturer
          CO2 Standards for Custom Chassis Vocational Vehicles
                              [g/ton-mile]
------------------------------------------------------------------------
                                      Assigned vehicle      MY 2027 and
         Vehicle type \a\               service class          later
------------------------------------------------------------------------
School bus........................  Medium HDV..........             271
Motor home........................  Medium HDV..........             226
Coach bus.........................  Heavy HDV...........             205
Other bus.........................  Heavy HDV...........             286
Refuse hauler.....................  Heavy HDV...........             298
Concrete mixer....................  Heavy HDV...........             316
Mixed-use vehicle.................  Heavy HDV...........             316

Emergency vehicle.................  Heavy HDV...........             319
------------------------------------------------------------------------
\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).

    (ii) The following standards apply for tractors instead of the
standards specified in Sec.  1037.106:

 Table 3 of Paragraph (c)(2)(ii) of Sec.   1037.150--Small manufacturer
      CO2 Standards for Class 7 and Class 8 Tractors by Subcategory
                              [g/ton-mile]
------------------------------------------------------------------------
                                                              Phase 2
                                                           standards for
                     Subcategory\a\                         model year
                                                          2027 and later
------------------------------------------------------------------------
Class 7 Low-Roof (all cab styles).......................            96.2
Class 7 Mid-Roof (all cab styles).......................           103.4
Class 7 High-Roof (all cab styles)......................           100.0
Class 8 Low-Roof Day Cab................................            73.4
Class 8 Low-Roof Sleeper Cab............................            64.1
Class 8 Mid-Roof Day Cab................................            78.0
Class 8 Mid-Roof Sleeper Cab............................            69.6
Class 8 High-Roof Day Cab...............................            75.7
Class 8 High-Roof Sleeper Cab...........................            64.3
Heavy-Haul Tractors.....................................            48.3
------------------------------------------------------------------------
\a\ Subcategory terms are defined in Sec.   1037.801.

    (iii) Small manufacturers producing vehicles that run on any fuel
other than gasoline, E85, or diesel fuel may delay complying with the
model year 2027 standards under this paragraph (c) by one model year.
    (iv) Label qualifying vehicles with the following statement: ``THIS
VEHICLE MEETS PHASE 2 STANDARDS AS ALLOWED UNDER 40 CFR 1037.150(c).''
    (v) Small manufacturers may bank emission credits only by
certifying all their vehicle families within a given averaging set to
the Phase 3 standards that apply for the current model year.
    (vi) The battery durability monitor requirements of Sec.
1037.115(f) apply for vehicles subject to standards under this
paragraph (c).
    (3) See paragraphs (r), (t), (u), and (w) of this section for
additional allowances for small manufacturers.
* * * * *
    (f) Testing exemption for qualifying vehicles. Tailpipe
CO2 emissions from battery electric vehicles, fuel cell
electric vehicles, and vehicles with engines fueled with neat hydrogen
are deemed to be zero. No CO2-related testing is required
under this part for these vehicles.
* * * * *
    (p) Credit multiplier for advanced technology. You may calculate
credits you generate from vehicles certified with advanced technology
as follows:
    (1) For Phase 1 vehicles, multiply the credits by 1.50, except that
you may not apply this multiplier in addition to the early-credit
multiplier of paragraph (a) of this section.
    (2) For model year 2026 and earlier, apply multipliers of 3.5 for
plug-in hybrid electric vehicles, 4.5 for battery electric vehicles,
and 5.5 for fuel cell electric vehicles; calculate credits relative to
the Phase 2 standard. In model year 2027, the advanced technology
multiplier applies only for fuel cell electric vehicles, with credits
multiplied relative to the Phase 3 standard.
* * * * *
    (x) Transition to updated GEM. (1) Vehicle manufacturers may
demonstrate compliance with Phase 2 greenhouse gas standards in model
years 2021 through 2023 using GEM Phase 2, Version 3.0, Version 3.5.1,
or Version 4.0 (all incorporated by reference, see Sec.  1037.810).
Manufacturers may change to a different version of GEM for model years
2022 and 2023 for a given vehicle family after initially submitting an
application for certification; such a change must be documented as an
amendment under Sec.  1037.225. Manufacturers may submit an end-of-year
report for model year 2021 using any of the three regulatory versions
of GEM, but only for demonstrating compliance with the custom-chassis
standards in Sec.  1037.105(h); such a change must be documented in the
report submitted under Sec.  1037.730. Once a manufacturer certifies a
vehicle family based on GEM Version 4.0, it may not revert back to
using GEM Phase 2, Version 3.0 or Version 3.5.1 for that vehicle family
in any model year.
    (2) Vehicle manufacturers may certify for model years 2021 through
2023 based on fuel maps from engines or powertrains that were created
using GEM Phase 2, Version 3.0, Version 3.5.1, or Version 4.0 (all
incorporated by reference, see Sec.  1037.810). Vehicle manufacturers
may alternatively certify in those years based on fuel maps from
powertrains that were created using GEM Phase 2, Version 3.0, GEM HIL
model 3.8, or GEM Phase 2, Version 4.0 (all incorporated by reference,
see

Sec.  1037.810). Vehicle manufacturers may continue to certify vehicles
in later model years using fuel maps generated with earlier versions of
GEM for model year 2024 and later vehicle families that qualify for
using carryover provisions in Sec.  1037.235(d).
    (y) Correcting credit calculations. If you notify us by October 1,
2024 that errors mistakenly decreased your balance of emission credits
for 2020 or any earlier model years, you may correct the errors and
recalculate the balance of emission credits after applying a 10 percent
discount to the credit correction.
0
55. Amend Sec.  1037.205 by revising the introductory text, paragraphs
(b) introductory text, (b)(6), (e), (o), and (q) to read as follows:

Sec.  1037.205  What must I include in my application?

    This section specifies the information that must be in your
application, unless we ask you to include less information under Sec.
1037.201(c). We may require you to provide additional information to
evaluate your application. References to testing and emission-data
vehicles refer to testing vehicles or components to measure any
quantity that serves as an input value for modeling emission rates
under Sec.  1037.520.
* * * * *
    (b) Explain how the emission control system operates. As
applicable, describe in detail all system components for controlling
greenhouse gas emissions, including all auxiliary emission control
devices (AECDs) and all fuel-system components you will install on any
production vehicle. Identify the part number of each component you
describe. For this paragraph (b), treat as separate AECDs any devices
that modulate or activate differently from each other. Also describe
your modeling inputs as described in Sec.  1037.520, with the following
additional information if it applies for your vehicles:
* * * * *
    (6) If you perform powertrain testing under 40 1036.545, report
both CO2 and NOX emission levels corresponding to
each test run.
* * * * *
    (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 and
1037.527. Describe which type of data you are using for engine fuel
maps (see 40 CFR 1036.505).
* * * * *
    (o) Report calculated and modeled emission results as for ten
configurations. Include modeling inputs and detailed descriptions of
how they were derived. Unless we specify otherwise, include the
configuration with the highest modeling result, the lowest modeling
result, and the configurations with the highest projected sales.
* * * * *
    (q) For battery electric vehicles and plug-in hybrid electric
vehicles, describe the recharging procedures and methods for
determining battery performance, such as state of charge and charging
capacity. Also include the certified usable battery energy for each
battery durability subfamily.
* * * * *

Sec.  1037.230  [Amended]

0
56. Amend Sec.  1037.230 by removing paragraphs (a)(3) and (d)(3).
0
57. Amend Sec.  1037.231 by revising paragraph (a) to read as follows:

Sec.  1037.231  Powertrain families.

    (a) If you choose to perform powertrain testing as specified in 40
CFR 1036.545, use good engineering judgment to divide your product line
into powertrain families that are expected to have similar fuel
consumptions and CO2 emission characteristics throughout the
useful life. Your powertrain family is limited to a single model year.
* * * * *
0
58. Amend Sec.  1037.235 by revising the introductory text, paragraphs
(a) and (c)(3) and removing paragraph (g)(3) to read as follows:

Sec.  1037.235  Testing requirements for certification.

    This section describes the emission testing you must perform to
show compliance with respect to the greenhouse gas emission standards
in subpart B of this part, and to determine any input values from Sec.
1037.520 that involve measured quantities.
    (a) Select emission-data vehicles that represent production
vehicles and components for the vehicle family consistent with the
specifications in Sec. Sec.  1037.205(o) and 1037.520. Where the test
results will represent multiple vehicles or components with different
emission performance, use good engineering judgment to select worst-
case emission data vehicles or components. In the case of powertrain
testing under 40 CFR 1036.545, select a test engine, test hybrid
components, test axle and test transmission as applicable, by
considering the whole range of vehicle models covered by the powertrain
family and the mix of duty cycles specified in Sec.  1037.510. If the
powertrain has more than one transmission calibration, for example
economy vs. performance, you may weight the results from the powertrain
testing in 40 CFR 1036.545 by the percentage of vehicles in the family
by prior model year for each configuration. This can be done, for
example, through the use of survey data or based on the previous model
year's sales volume. Weight the results of Mfuel[cycle]
[GRAPHIC] [TIFF OMITTED] TP27AP23.069

and W[cycle] from Table 2 of 40 CFR 1036.545 according to
the percentage of vehicles in the family that use each transmission
calibration.
* * * * *
    (c) * * *
    (3) Before we test one of your vehicles or components, we may set
its adjustable parameters to any point within the practically
adjustable ranges, if applicable.
* * * * *
0
59. Amend Sec.  1037.241 to read as follows:

Sec.  1037.241  Demonstrating compliance with exhaust emission
standards for greenhouse gas pollutants.

    (a) Compliance determinations for purposes of certification depend
on whether or not you participate in the ABT program in subpart H of
this part.
    (1) If none of your vehicle families generate or use emission
credits in a given model year, each of your vehicle families is
considered in compliance with the CO2 emission standards in
Sec. Sec.  1037.105 and 1037.106 if all vehicle configurations in the
family have calculated or modeled CO2 emission rates from
Sec.  1037.520 that are at or below the applicable standards. A vehicle
family is deemed not to comply if any vehicle configuration in the
family has a calculated or modeled CO2 emission rate that is
above the applicable standard.
    (2) If you generate or use emission credits with one or more
vehicle families in a given model year, your vehicle families within an
averaging set are considered in compliance with the CO2
emission standards in Sec. Sec.  1037.105 and 1037.106 if the sum of
positive and negative credits for all vehicle configurations in those
vehicle families lead to a zero balance or a positive balance of
credits, except as allowed bySec.  1037.745. Note that the FEL is
considered to be the applicable emission standard for an individual
configuration.

    (b) We may require you to provide an engineering analysis showing
that the performance of your emission controls will not deteriorate
during the useful life with proper maintenance. If we determine that
your emission controls are likely to deteriorate during the useful
life, we may require you to develop and apply deterioration factors
consistent with good engineering judgment. For example, you may need to
apply a deterioration factor to address deterioration of battery
performance for a hybrid vehicle. Where the highest useful life
emissions occur between the end of useful life and at the low-hour test
point, base deterioration factors for the vehicles on the difference
between (or ratio of) the point at which the highest emissions occur
and the low-hour test point.

Sec.  1037.310  [Removed]

0
60. Remove Sec.  1037.310.
0
61. Amend Sec.  1037.315 by revising paragraph (a) to read as follows:

Sec.  1037.315  Audit procedures related to powertrain testing.

    (a) For vehicles certified based on powertrain testing as specified
in 40 CFR 1036.545, we may apply the selective enforcement audit
requirements to the powertrain. If engine manufacturers perform the
powertrain testing and include those results in their certification
under 40 CFR part 1036, they are responsible for selective enforcement
audits related to those results. Otherwise, the certificate holder for
the vehicle is responsible for the selective enforcement audit.
* * * * *
0
62. Amend Sec.  1037.401 by revising paragraph (b) to read as follows:

Sec.  1037.401  General provisions.

* * * * *
    (b) We may measure the drag area of a vehicle you produced after it
has been placed into service. We may use any of the procedures as
specified in Sec. Sec.  1037.525 and 1037.527 for measuring drag area.
Your vehicle conforms to the regulations of this part with respect to
aerodynamic performance if we measure its drag area to be at or below
the maximum drag area allowed for the bin to which that configuration
was certified.
0
63. Amend Sec.  1037.501 by revising paragraphs (a) and (h) and
removing paragraph (i) to read as follows:

Sec.  1037.501  General testing and modeling provisions.

* * * * *
    (a) Except as specified in subpart B of this part, you must
demonstrate that you meet emission standards using emission modeling as
described in Sec.  1037.520. This modeling depends on several measured
values as described in this subpart F. You may use fuel-mapping
information from the engine manufacturer as described in 40 CFR
1036.535 and 1036.540, or you may use powertrain testing as described
in 40 CFR 1036.545.
* * * * *
    (h) Note that declared GEM inputs for fuel maps and aerodynamic
drag area typically includes compliance margins to account for testing
variability; for other measured GEM inputs, the declared values are
typically the measured values without adjustment.
0
64. Amend Sec.  1037.510 by:
0
a. Revising paragraphs (a) introductory text, (a)(2) introductory text,
and (a)(2)(iii) and (iv);
0
b. In paragraph (b) in Equation 1037.510-1, in the Where entries for
vmoving and w[cycle], removing the text ``table 1
to this section'' and adding, in its place, the text ``table 1 of this
section''; and
0
c. Revising paragraphs (c)(3) and (d).
    The revisions read as follows:

Sec.  1037.510  Duty-cycle exhaust testing.

* * * * *
    (a) Measure emissions by testing the powertrain on a powertrain
dynamometer with the applicable duty cycles. Each duty cycle consists
of a series of speed commands over time--variable speeds for the
transient test and constant speeds for the highway cruise tests. None
of these cycles include vehicle starting or warmup.
* * * * *
    (2) Perform cycle-average engine fuel mapping as described in 40
CFR 1036.540. For powertrain testing under 40 CFR 1036.545 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:
* * * * *
    (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(d). 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 (601) seconds and then sample
emissions for (301) 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(d). 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 (1801) seconds
and then sample emissions for (6001) seconds.
* * * * *
    (c) * * *
    (3) Table 1 follows:

                                    Table 1 of Paragraph (c)(3) of Sec.   1037.510--Weighting Factors for Duty Cycles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Distance-weighted                               Time-weighted \a\
                                         ------------------------------------------------------------------------------------------------  Average speed
                                                             55 mi/hr        65 mi/hr                                                       during non-
                                             Transient        cruise          cruise        Drive idle      Parked idle      Non-idle       idle cycles
                                             (percent)       (percent)       (percent)       (percent)       (percent)       (percent)      (mi/hr) \b\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Day Cabs................................              19              17              64  ..............  ..............  ..............  ..............
Sleeper Cabs............................               5               9              86  ..............  ..............  ..............  ..............
Heavy-haul Tractors.....................              19              17              64  ..............  ..............  ..............  ..............
Vocational--Regional....................              20              24              56               0              25              75           38.41
Vocational--Multi-Purpose (2b-7)........              54              29              17              17              25              58           23.18
Vocational--Multi-Purpose (8)...........              54              23              23              17              25              58           23.27
Vocational--Urban (2b-7)................              92               8               0              15              25              60           16.25
Vocational--Urban (8)...................              90              10               0              15              25              60           16.51
Vocational with conventional powertrain               42              21              37  ..............  ..............  ..............  ..............
 (Phase 1 only).........................

Vocational Hybrid Vehicles (Phase 1                   75               9              16  ..............  ..............  ..............  ..............
 only)..................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Note that these drive idle and non-idle weighting factors do not reflect additional drive idle that occurs during the transient cycle. The transient
  cycle does not include any parked idle.
\b\ These values apply even for vehicles not following the specified speed traces.

* * * * *
    (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 40 CFR 1036.545(g)(1). If the speeds do not conform to
these criteria, the test is not valid and must be repeated.
* * * * *

Sec.  1037.515  [Removed]

0
65. Remove Sec.  1037.515.
0
66. Amend Sec.  1037.520 by revising the introductory text and
paragraphs (a)(2) introductory text, (b)(3), (e)(1) and (3), (g)(4),
and (j)(1) to read as follows:

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

    This section describes how to use the Greenhouse gas Emissions
Model (GEM) to show compliance with the CO2 standards of
Sec. Sec.  1037.105 and 1037.106 for vocational vehicles and tractors.
Use GEM version 2.0.1 to demonstrate compliance with Phase 1 standards;
use GEM Phase 2, Version 4.0 to demonstrate compliance with Phase 2 and
Phase 3 standards (both incorporated by reference, see Sec.  1037.810).
Use good engineering judgment when demonstrating compliance using GEM.
    (a) * * *
    (2) For Phase 2 and Phase 3 vehicles, the GEM inputs described in
paragraphs (a)(1)(i) through (v) of this section continue to apply.
Note that the provisions in this part related to vehicle speed limiters
and automatic engine shutdown systems are available for vocational
vehicles in Phase 2 and Phase 3. The rest of this section describes
additional GEM inputs for demonstrating compliance with Phase 2 and
Phase 3 standards. Simplified versions of GEM apply for limited
circumstances as follows:
    (b) * * *
    (3) For Phase 2 and Phase 3 tractors other than heavy-haul
tractors, determine bin levels and CdA inputs as follows:
    (i) Determine bin levels for high-roof tractors based on
aerodynamic test results as specified in Sec.  1037.525 and summarized
in the following table:

   Table 3 to Paragraph (b)(3)(i) of Sec.   1037.520--Bin Determinations for Phase 2 and Phase 3 High-Roof Tractors Based on Aerodynamic Test Results
                                                                      [CdA in m\2\]
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Tractor type                     Bin I          Bin II          Bin III         Bin IV           Bin V          Bin VI          Bin VII
--------------------------------------------------------------------------------------------------------------------------------------------------------
Day Cabs................................           >=7.2         6.6-7.1         6.0-6.5         5.5-5.9         5.0-5.4         4.5-4.9           <=4.4
Sleeper Cabs............................           >=6.9         6.3-6.8         5.7-6.2         5.2-5.6         4.7-5.1         4.2-4.6           <=4.1
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (ii) For low- and mid-roof tractors, you may either use the same
bin level that applies for an equivalent high-roof tractor as shown in
Table 3 of this section, or you may determine your bin level based on
aerodynamic test results as described in Table 4 of this section.

 Table 4 to Paragraph (b)(3)(ii) of Sec.   1037.520--Bin Determinations for Phase 2 and Phase 3 Low-Roof and Mid-Roof Tractors Based on Aerodynamic Test
                                                                         Results
                                                                      [CdA in m\2\]
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Tractor type                     Bin I          Bin II          Bin III         Bin IV           Bin V          Bin VI          Bin VII
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-Roof Cabs...........................           >=5.4         4.9-5.3         4.5-4.8         4.1-4.4         3.8-4.0         3.5-3.7           <=3.4
Mid-Roof Cabs...........................           >=5.9         5.5-5.8         5.1-5.4         4.7-5.0         4.4-4.6         4.1-4.3           <=4.0
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (iii) Determine the CdA input according to the tractor's
bin level as described in the following table:

                     Table 5 to Paragraph (b)(3)(iii) of Sec.   1037.520--Phase 2 and Phase 3 CdA Tractor Inputs Based on Bin Level
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Tractor type                     Bin I          Bin II          Bin III         Bin IV           Bin V          Bin VI          Bin VII
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-Roof Day Cabs......................            7.45            6.85            6.25            5.70            5.20            4.70            4.20
High-Roof Sleeper Cabs..................            7.15            6.55            5.95            5.40            4.90            4.40            3.90
Low-Roof Cabs...........................            6.00            5.60            5.15            4.75            4.40            4.10            3.80
Mid-Roof Cabs...........................            7.00            6.65            6.25            5.85            5.50            5.20            4.90
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *
    (e) * * *
    (1) Vehicle weight reduction inputs for wheels are specified
relative to dual-wide tires with conventional steel wheels. For
purposes of this paragraph (e)(1), an aluminum alloy qualifies as
light-weight if a dual-wide drive wheel made from this material weighs
at least 21 pounds less than a comparable conventional steel wheel. The
inputs are listed in Table 6 of this section. For example, a tractor or
vocational vehicle with aluminum steer wheels and eight (4 x 2) dual-
wide aluminum drive wheels would have an input of 210 pounds (2 x 21 +
8 x 21).

                           Table 6 to Sec.   1037.520--Wheel-Related Weight Reductions
----------------------------------------------------------------------------------------------------------------
                                                                                Weight
                                                                                Weight        reduction--
                                                                                reduction--    Phase 2  and
                   Tire type                                Material                  Phase 1         Phase 3
                                                                                (pounds per     (pounds per
                                                                                wheel)          wheel)
----------------------------------------------------------------------------------------------------------------
Wide-Base Single Drive Tire with . . .\a\.....  Steel Wheel.....................              84              84
                                                Aluminum Wheel..................             139             147
                                                Light-Weight Aluminum Alloy                  147             147
                                                 Wheel.
Steer Tire or Dual-wide Drive Tire with . . ..  High-Strength Steel Wheel.......               8               8
                                                Aluminum Wheel..................              21              25
                                                Light-Weight Aluminum Alloy                   30              25
                                                 Wheel.
----------------------------------------------------------------------------------------------------------------
\a\ The weight reduction for wide-base tires accounts for reduced tire weight relative to dual-wide tires.

* * * * *
    (3) Weight-reduction inputs for vocational-vehicle components other
than wheels are specified in the following table:

 Table 8 to Sec.   1037.520--Nonwheel-Related Weight Reductions From Alternative Materials for Phase 2 and Phase
                                              3 Vocational Vehicles
                                                  [pounds] \a\
----------------------------------------------------------------------------------------------------------------
                                                                                Vehicle type
               Component                        Material         -----------------------------------------------
                                                                     Light HDV    Medium HDV \b\     Heavy HDV
----------------------------------------------------------------------------------------------------------------
Axle Hubs--Non-Drive..................  Aluminum................                40                            40
                                                                 -----------------------------------------------
Axle Hubs--Non-Drive..................  High Strength Steel.....                 5                             5
                                                                 -----------------------------------------------
Axle--Non-Drive.......................  Aluminum................                60                            60
                                                                 -----------------------------------------------
Axle--Non-Drive.......................  High Strength Steel.....                15                            15
                                                                 -----------------------------------------------
Brake Drums--Non-Drive................  Aluminum................                60                            60
                                                                 -----------------------------------------------
Brake Drums--Non-Drive................  High Strength Steel.....                42                            42
                                                                 -----------------------------------------------
Axle Hubs--Drive......................  Aluminum................                40                            80
                                                                 -----------------------------------------------
Axle Hubs--Drive......................  High Strength Steel.....                10                            20
                                                                 -----------------------------------------------
Brake Drums--Drive....................  Aluminum................                70                           140
                                                                 -----------------------------------------------
Brake Drums--Drive....................  High Strength Steel.....                37                            74
                                                                 -----------------------------------------------
Suspension Brackets, Hangers..........  Aluminum................                67                           100
                                                                 -----------------------------------------------
Suspension Brackets, Hangers..........  High Strength Steel.....                20                            30
                                                                 -----------------------------------------------
Crossmember--Cab......................  Aluminum................              10              15              15
Crossmember--Cab......................  High Strength Steel.....               2               5               5
Crossmember--Non-Suspension...........  Aluminum................              15              15              15
Crossmember--Non-Suspension...........  High Strength Steel.....               5               5               5
Crossmember--Suspension...............  Aluminum................              15              25              25
Crossmember--Suspension...............  High Strength Steel.....               6               6               6
Driveshaft............................  Aluminum................              12              40              50
Driveshaft............................  High Strength Steel.....               5              10              12
Frame Rails...........................  Aluminum................             120             300             440
Frame Rails...........................  High Strength Steel.....              40              40              87
----------------------------------------------------------------------------------------------------------------
\a\ Weight-reduction values apply per vehicle unless otherwise noted.
\b\ For Medium HDV with 6 x 4 or 6 x 2 axle configurations, use the values for Heavy HDV.

* * * * *
* * * * *
    (g) * * *
    (4) GEM inputs associated with powertrain testing include
powertrain family, transmission calibration identifier, test data from
40 CFR 1036.545, and the powertrain test configuration (dynamometer
connected to transmission output or wheel hub). You do not need to
identify or provide inputs for transmission gear ratios, fuel map data,
or engine torque curves, which would otherwise be required under
paragraph (f) of this section.
* * * * *
    (j) * * *
    (1) Intelligent controls. Enter 2 for tractors with predictive
cruise control. This includes any cruise control system that
incorporates satellite-based global-positioning data for controlling
operator demand. For tractors without predictive cruise control and for
all vocational vehicles, enter 1.5 if they have neutral coasting or
full cylinder deactivation when coasting, unless good engineering
judgment indicates that a lower percentage should apply.
* * * * *
0
67. Amend Sec.  1037.525 by revising paragraphs (a) introductory text,
(b)(1), (4), and (5), (c)(1) introductory text, and (c)(2) introductory
text to read as follows:

Sec.  1037.525  Aerodynamic measurements for tractors.

* * * * *
    (a) General provisions. The GEM input for a tractor's aerodynamic
performance is a Cd value for Phase 1 and a CdA
value for Phase 2 and Phase 3. The input value is measured or
calculated for a tractor in a specific test configuration with a
trailer, such as a high-roof tractor with a box van meeting the
requirements for the standard trailer.
* * * * *
    (b) * * *
    (1) Determine the functional relationship between your alternate
method and coastdown testing. Specify this functional relationship as
Falt-aero for a given alternate drag measurement method. The
effective yaw angle, [psi]eff, is assumed to be zero degrees
for Phase 1. For Phase 2 and Phase 3, determine [Psi]eff
from coastdown test results using the following equation:
[GRAPHIC] [TIFF OMITTED] TP27AP23.070

Where:

CdAcoastdown([psi]eff) = the
average drag area measured during coastdown at an effective yaw
angle, [psi]eff.
CdAalt([psi]eff) = the average drag
area calculated from an alternate drag measurement method at an
effective yaw angle, [psi]eff.
* * * * *
    (4) Measure the drag area using your alternate method for a Phase 2
and Phase 3 tractor used to determine Falt-aero with testing
at yaw angles of 0[deg], 1[deg], 3[deg], 4.5[deg], 6[deg], and 9[deg] (you may
include additional angles), using direction conventions described in
Figure 2 of SAE J1252 (incorporated by reference, see Sec.  1037.810).
Also, determine the drag area at the coastdown effective yaw angle,
CdAalt([psi]eff), by taking the
average drag area at [psi]eff and -[psi]eff for
your vehicle using the same alternate method.
    (5) For Phase 2 and Phase 3 testing, determine separate values of
Falt-aero for at least one high-roof day cab and one high-
roof sleeper cab for model year 2021, at least two high-roof day cabs
and two high-roof sleeper cabs for model year 2024, and at least three
high-roof day cabs and three high-roof sleeper cabs for model year
2027. These test requirements are cumulative; for example, you may meet
these requirements by testing two vehicles to support model year 2021
certification and four additional vehicles to support model year 2023
certification. For any untested tractor models, apply the value of
Falt-aero from the tested tractor model that best represents
the aerodynamic characteristics of the untested tractor model,
consistent with good engineering judgment. Testing under this paragraph
(b)(5) continues to be valid for later model years until you change the
tractor model in a way that causes the test results to no longer
represent production vehicles. You must also determine unique values of
Falt-aero for low-roof and mid-roof tractors if you
determine CdA values based on low or mid-roof tractor
testing as shown in Table 4 of Sec.  1037.520. For Phase 1 testing, if
good engineering judgment allows it, you may calculate a single,
constant value of Falt-aero for your whole product line by
dividing the coastdown drag area, CdAcoastdown,
by drag area from your alternate method, CdAalt.
* * * * *
    (c) * * *
    (1) Apply the following method for all Phase 2 and Phase 3 testing
with an alternate method:
* * * * *
    (2) Apply the following method for Phase 2 and Phase 3 coastdown
testing other than coastdown testing used to establish
Falt-aero:
* * * * *

Sec.  1037.526  [Removed]

0
68. Remove Sec.  1037.526.
0
69. Revise Sec.  1037.527 to read as follows:

Sec.  1037.527  Aerodynamic measurements for vocational vehicles.

    This section describes a methodology for determining vocational
vehicle aerodynamic input values for as described in Sec.  1037.520.
This measurement is optional. A vocational vehicle's aerodynamic
performance is based on a [Delta]CdA value relative to a
baseline vehicle. Determine a [Delta]CdA value by performing
A to B testing as follows:
    (a) Determine a baseline CdA value for a vehicle
representing a production configuration without the aerodynamic
improvement. Repeat this testing and measure CdA for a
vehicle with the improved aerodynamic design.
    (b) Use good engineering judgment to perform paired tests that
accurately demonstrate the reduction in aerodynamic drag associated
with the improved design.
    (c) Measure CdA in m2 to two decimal places.
Calculate [Delta]CdA by subtracting the drag area for the
test vehicle from the drag area for the baseline vehicle.
0
70. Amend Sec.  1037.528 by:
0
a. Revising the introductory text, paragraphs (b) introductory text and
(h)(5)(iv);
0
b. Removing paragraph (h)(7);
0
c. Redesignating paragraphs (h)(8) through (12) as paragraphs (h)(7)
through (11); and
0
d. Revising newly redesignated paragraph (h)(10).
    The revisions read as follows:

Sec.  1037.528  Coastdown procedures for calculating drag area
(CdA).

    The coastdown procedures in this section describe how to calculate
drag area, CdA, for Phase 2 and Phase 3 tractors and
vocational vehicles, subject to the provisions of Sec. Sec.  1037.525
and 1037.527. These procedures are considered the reference method for
tractors. Follow the provisions of Sections 1 through 9 of SAE J2263
(incorporated by reference, see Sec.  1037.810), with the
clarifications and exceptions described in this section. Several of
these exceptions are from SAE J1263 (incorporated by reference, see
Sec.  1037.810). The coastdown procedures in 40 CFR 1066.310 apply
instead of the provisions of this section for Phase 1 tractors.
* * * * *
    (b) To determine CdA values for a tractor, perform
coastdown testing with a tractor-trailer combination using the
manufacturer's tractor and a standard

trailer. Prepare the vehicles for testing as follows:
* * * * *
    (h) * * *
    (5) * * *
    (iv) Calculate [Delta]Fspin using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP27AP23.119

Example:

[Delta]Fspin = 129.7-52.7
[Delta]Fspin = 77.0 N
* * * * *
    (10) Calculate drag area, CdA, in m2 for each
high-speed segment using the following equation, expressed to at least
three decimal places:
[GRAPHIC] [TIFF OMITTED] TP27AP23.071

Where:

Fhi = road load force at high speed determined from Eq.
1037.528-7.
Flo,pair = the average of Flo values for a
pair of opposite direction runs calculated as described in paragraph
(h)(9) of this section.
[Delta]Fspin = the difference in drive-axle spin loss
force between high-speed and low-speed coastdown segments. This is
described in paragraph (h)(5) of this section for tractor testing.
[Delta]FTRR = the difference in tire rolling resistance
force between high-speed and low-speed coastdown segments as
described in paragraph (h)(6) of this section.
v2air,lo,pair = the average of
v2air,lo values for a pair of opposite
direction runs calculated as described in paragraph (h)(9) of this
section.
R = specific gas constant = 287.058 J/(kg[middot]K).
T = mean air temperature expressed to at least one decimal Place.
pact = mean absolute air pressure expressed to at least
one decimal place.

    Example:
    [GRAPHIC] [TIFF OMITTED] TP27AP23.072

* * * * *
0
71. Amend Sec.  1037.530 by revising the introductory text, paragraphs
(a) introductory text, (c), and (d) introductory text to read as
follows:

Sec.  1037.530  Wind-tunnel procedures for calculating drag area
(CdA).

    The wind-tunnel procedure specified in this section is an alternate
procedure for tractors.
    (a) You may measure drag areas consistent with published SAE
procedures as described in this section using any wind tunnel
recognized by the Subsonic Aerodynamic Testing Association, subject to
the provisions of Sec. Sec.  1037.525 and 1037.527. If your wind tunnel
does not meet the specifications described in this section, you may ask
us to approve it as an alternate method under Sec.  1037.525(d). All
wind tunnels and wind tunnel tests must meet the specifications
described in SAE J1252 (incorporated by reference, see Sec.  1037.810),
with the following exceptions and additional provisions:
* * * * *
    (c) To determine CdA values for certifying tractors,
perform wind-tunnel testing with a tractor-trailer combination using
the manufacturer's tractor and a standard trailer. Use a moving/rolling
floor if the facility has one. For Phase 1 tractors, conduct the wind
tunnel tests at a zero yaw angle. For Phase 2 and Phase 3 vehicles,
conduct the wind tunnel tests by measuring the drag area at yaw angles
of +4.5[deg] and -4.5[deg] and calculating the average of those two
values.
    (d) In your request to use wind-tunnel testing for tractors,
describe how you meet all the specifications that apply under this
section, using terminology consistent with SAE J1594 (incorporated by
reference, see Sec.  1037.810). If you request our approval to use
wind-tunnel testing even though you do not meet all the specifications
of this section, describe how your method nevertheless qualifies as an
alternate method under Sec.  1037.525(d) and include all the following
information:
* * * * *
0
72. Amend Sec.  1037.532 by revising the introductory text, paragraphs
(a) introductory text, (b), and (c) introductory text to read as
follows:

Sec.  1037.532  Using computational fluid dynamics to calculate drag
area (CdA).

    This section describes how to use commercially available
computational fluid dynamics (CFD) software to determine CdA
values, subject to the provisions of Sec. Sec.  1037.525 and 1037.527.
This is considered to be an alternate method for tractors.
    (a) For Phase 2 and Phase 3 vehicles, use SAE J2966 (incorporated
by

reference, see Sec.  1037.810), with the following clarifications and
exceptions:
* * * * *
    (b) For Phase 1 tractors, apply the procedures as specified in
paragraphs (c) through (f) of this section. Paragraphs (c) through (f)
of section apply for Phase 2 and Phase 3 vehicles only as specified in
paragraph (a) of this section.
    (c) To determine CdA values for certifying a tractor,
perform CFD modeling based on a tractor-trailer combination using the
manufacturer's tractor and a standard trailer. Perform all CFD modeling
as follows:
* * * * *
0
73. Amend Sec.  1037.540 by:
0
a. Revising the introductory text and paragraphs (c)(2) and (5),
(d)(4), and (f) introductory text; and
0
b. In paragraph (f)(3), by removing the text ``the approved utility
factor curve'' and adding, in its place, the text ``the utility factor
curve in appendix E of this part''.

    The revisions 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 40 CFR 1036.545 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
electric 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 that
use a technology other than batteries for storing energy, consistent
with good engineering judgment. For plug-in hybrid electric vehicles,
use a utility factor to properly weight charge-sustaining and charge-
depleting operation as described in paragraph (f)(3) of this section.
* * * * *
    (c) * * *
    (2) Prepare the vehicle for testing by operating it as needed to
stabilize the RESS at a full state of charge (or equivalent for
vehicles that use a technology other than batteries for storing
energy).
* * * * *
    (5) Operate the vehicle over one or both of the denormalized PTO
duty cycles without turning the vehicle off, until the engine starts
and then shuts down. This may require running multiple repeats of the
PTO duty cycles. For systems that are not plug-in hybrid systems, the
test cycle is completed once the engine shuts down. For plug-in hybrid
systems, continue running until the PTO hybrid is running in a charge-
sustaining mode such that the ``End of Test'' requirements defined in
40 CFR 1066.501 are met. Measure emissions as described in paragraph
(b)(7) of this section. Use good engineering judgment to minimize the
variability in testing between the two types of vehicles.
* * * * *
    (d) * * *
    (4) Divide the total PTO operating time from paragraph (d)(3) of
this section by a conversion factor of 0.0144 hr/mi for Phase 1 and
0.0217 hr/mi for Phase 2 and Phase 3 to determine the equivalent
distance driven. The conversion factors are based on estimates of
average vehicle speed and PTO operating time as a percentage of total
engine operating time; the Phase 2 and Phase 3 conversion factor is
calculated from an average speed of 27.1 mi/hr and PTO operation 37% of
engine operating time, as follows:
[GRAPHIC] [TIFF OMITTED] TP27AP23.073

* * * * *
    (f) For Phase 2 and Phase 3, calculate the delta PTO fuel results
for input into GEM during vehicle certification as follows:
* * * * *

Sec.  1037.550--[Removed]

0
74. Remove Sec.  1037.550.
0
75. 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.

    40 CFR 1036.545 describes how to measure fuel consumption over
specific duty cycles with an engine coupled to a transmission; 40 CFR
1036.545(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 40 CFR 1036.545(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 40 CFR
1036.545(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
76. Amend Sec.  1037.555 by revising the introductory text 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 40 CFR 1036.545 for Phase 2 and Phase 3
hybrid systems.
* * * * *
0
77. Amend Sec.  1037.560 by revising paragraph (e)(2) to read as
follows:

Sec.  1037.560  Axle efficiency test.

* * * * *
    (e) * * *
    (2) Maintain gear oil temperature at (81 to 83) [deg]C. You may
alternatively specify a lower range by shifting both temperatures down
by the same amount for all test points or on a test point by test point
basis. We will test your axle assembly using the same temperature range
you specify for your testing. You may use an external gear oil
conditioning system, as long as it does not affect measured values.
* * * * *
0
78. Amend Sec.  1037.601 by revising paragraph (b) to read as follows:

Sec.  1037.601  General compliance provisions.

* * * * *
    (b) Vehicles exempted from the applicable standards of 40 CFR part
86 or part 1036 other than glider vehicles are exempt from the
standards of this part without request. Similarly, vehicles other than
glider vehicles are exempt without request if the installed engine is
exempted from the applicable standards in 40 CFR part 86 or part 1036.
* * * * *
0
79. Amend Sec.  1037.610 by revising paragraph (f)(2) to read as
follows:

Sec.  1037.610  Vehicles with off-cycle technologies.

* * * * *
    (f) * * *
    (2) For model years 2021 and later, you may not rely on an approval
for model years before 2021. You must separately request our approval
before applying an improvement factor or credit under this section for
Phase 2 and Phase 3 vehicles, even if we approved an improvement factor
or credit for similar vehicle models before model year 2021. Note that
Phase 2 and Phase 3 approval may carry over for multiple years.
* * * * *
0
80. Amend Sec.  1037.615 by revising paragraphs (a) and (d) through (g)
to read as follows:

Sec.  1037.615  Advanced technologies.

    (a) This section describes how to calculate emission credits for
advanced technologies. You may calculate Phase 1 advanced technology
credits through model year 2020 for hybrid vehicles with regenerative
braking, vehicles equipped with Rankine-cycle engines, battery electric
vehicles, and fuel cell vehicles. You may calculate Phase 2 advanced
technology credits through model year 2026 for plug-in hybrid electric
vehicles, battery electric vehicles, and fuel cell vehicles. You may
calculate Phase 3 advanced technology credits for model year 2027 for
fuel cell vehicles. You may not generate credits for Phase 1 engine
technologies for which the engines generate credits under 40 CFR part
1036.
* * * * *
    (d) For Phase 2 and Phase 3 plug-in hybrid electric vehicles and
for fuel cells powered by any fuel other than hydrogen, calculate
CO2 credits using an FEL based on emission measurements from
powertrain testing. Phase 2 and Phase 3 advanced technology credits do
not apply for hybrid vehicles that have no plug-in capability.
    (e) [Reserved]
    (f) For battery electric vehicles and for fuel cell electric
vehicles, calculate CO2 credits using an FEL of 0 g/ton-
mile. Note that these vehicles are subject to compression-ignition
standards for CO2.
    (g) As specified in subpart H of this part, advanced-technology
credits generated from Phase 1 vehicles under this section may be used
under this part 1037 outside of the averaging set in which they were
generated, or they may be used under 40 CFR part 86, subpart S, or 40
CFR part 1036. Advanced-technology credits generated from Phase 2 and
Phase 3 vehicles are subject to all the averaging-set restrictions that
apply to other emission credits.
* * * * *

Sec.  1037.620  [Amended]

0
81. Amend Sec.  1037.620 by removing paragraph (c) and redesignating
paragraphs (d) through (f) as paragraphs (c) through (e).
0
82. Amend Sec.  1037.622 by revising the introductory text and
paragraph (d)(5) to read as follows:

Sec.  1037.622  Shipment of partially complete vehicles to secondary
vehicle manufacturers.

    This section specifies how manufacturers may introduce partially
complete vehicles into U.S. commerce (or in the case of certain custom
vehicles, introduce complete vehicles into U.S. commerce for
modification by a small manufacturer). The provisions of this section
are intended to accommodate normal business practices without
compromising the effectiveness of certified emission controls. You may
not use the provisions of this section to circumvent the intent of this
part. For vehicles subject to both exhaust greenhouse gas and
evaporative standards, the provisions of this part apply separately for
each certificate.
* * * * *
    (d) * * *
    (5) The provisions of this paragraph (d) may apply separately for
vehicle greenhouse gas, evaporative, and refueling emission standards.
* * * * *
0
83. AmendSec.  1037.630 by revising paragraphs (a)(1)(iii) and (c) to
read as follows:

Sec.  1037.630  Special purpose tractors.

    (a) * * *
    (1) * * *
    (iii) Model year 2020 and earlier tractors with a gross combination
weight rating (GCWR) at or above 120,000 pounds. Note that Phase 2 and
Phase 3 tractors meeting the definition of ``heavy-haul'' in Sec.
1037.801 must be certified to the heavy-haul standards in Sec. Sec.
1037.106 or 1037.670.
* * * * *
    (c) Production limit. No manufacturer may produce more than 21,000
Phase 1 vehicles under this section in any consecutive three model year
period. This means you may not exceed 6,000 in a given model year if
the combined total for the previous two years was 15,000. The
production limit applies with respect to all Class 7 and Class 8 Phase
1 tractors certified or exempted as vocational tractors. No production
limit applies for tractors subject to Phase 2 and Phase 3 standards.
* * * * *
0
84. Amend Sec.  1037.631 by revising paragraph (a) introductory text to
read as follows:

Sec.  1037.631  Exemption for vocational vehicles intended for off-road
use.

* * * * *
    (a) Qualifying criteria. Vocational vehicles intended for off-road
use are exempt without request, subject to the provisions of this
section, if they are primarily designed to perform work off-road (such
as in oil fields, mining, forests, or construction sites), and they
meet at least one of the criteria of paragraph (a)(1) of this section
and at least one of the criteria of paragraph (a)(2) of this section.
See Sec.  1037.105(h) for alternate Phase 2 and Phase 3 standards that
apply for vehicles meeting only one of these sets of criteria.
* * * * *
0
85. Amend Sec.  1037.635 by revising paragraph (b)(1) to read as
follows:

Sec.  1037.635  Glider kits and glider vehicles.

* * * * *
    (b) * * *
    (1) The engine must meet the greenhouse gas standards of 40 CFR
part 1036 that apply for the engine model year corresponding to the
vehicle's date of manufacture. For example, for a vehicle with a 2024
date of manufacture, the engine must meet the greenhouse gas standards
that apply for model year 2024.
* * * * *
0
86. Amend Sec.  1037.640 by revising the introductory text to read as
follows:

Sec.  1037.640  Variable vehicle speed limiters.

    This section specifies provisions that apply for vehicle speed
limiters (VSLs) that you model under Sec.  1037.520. This does not
apply for VSLs that you do not model under Sec.  1037.520. (e) This
section is written to apply for tractors; however, you may use good
engineering judgment to apply equivalent adjustments for Phase 2 and
Phase 3 vocational vehicles with vehicle speed limiters.

* * * * *
0
87. Amend Sec.  1037.660 by revising paragraphs (a)(1)(iv), (2), and
(3) to read as follows:

Sec.  1037.660  Idle-reduction technologies.

* * * * *
    (a) * * *
    (1) * * *
    (iv) For Phase 2 and Phase 3 tractors, you may identify AES systems
as ``adjustable'' if, before delivering to the ultimate purchaser, you
enable authorized dealers to modify the vehicle in a way that disables
the AES system or makes the threshold inactivity period longer than 300
seconds. However, the vehicle may not be delivered to the ultimate
purchaser with the AES system disabled or the threshold inactivity
period set longer than 300 seconds. You may allow dealers or repair
facilities to make such modifications; this might involve password
protection for electronic controls, or special tools that only you
provide. Any dealers making any modifications before delivery to the
ultimate purchaser must notify you, and you must account for such
modifications in your production and ABT reports after the end of the
model year. Dealers failing to provide prompt notification are in
violation of the tampering prohibition of 40 CFR 1068.101(b)(1). Dealer
notifications are deemed to be submissions to EPA. Note that these
adjustments may not be made if the AES system was not ``adjustable''
when first delivered to the ultimate purchaser.
* * * * *
    (2) Neutral idle. Phase 2 and Phase 3 vehicles with hydrokinetic
torque converters paired with automatic transmissions qualify for
neutral-idle credit in GEM modeling if the transmission reduces torque
equivalent to shifting into neutral throughout the interval during
which the vehicle's brake pedal is depressed and the vehicle is at a
zero-speed condition (beginning within five seconds of the vehicle
reaching zero speed with the brake depressed). If a vehicle reduces
torque partially but not enough to be equivalent to shifting to
neutral, you may use the provisions of Sec.  1037.610(g) to apply for
an appropriate partial emission reduction; this may involve A to B
testing with the powertrain test procedure in 40 CFR 1036.545 or the
spin-loss portion of the transmission efficiency test in Sec.
1037.565.
    (3) Stop-start. Phase 2 and Phase 3 vocational vehicles qualify for
stop-start reduction in GEM modeling if the engine shuts down no more
than 5 seconds after the vehicle's brake pedal is depressed when the
vehicle is at a zero-speed condition.
* * * * *
0
88. Amend Sec.  1037.665 by revising paragraphs (a)(1) and (d) to read
as follows:

Sec.  1037.665  Production and in-use tractor testing.

* * * * *
    (a) * * *
    (1) Each calendar year, select for testing three sleeper cabs and
two day cabs certified to Phase 1 or Phase 2 or Phase 3 standards. If
we do not identify certain vehicle configurations for your testing,
select models that you project to be among your 12 highest-selling
vehicle configurations for the given year.
* * * * *
    (d) Greenhouse gas standards do not apply with respect to testing
under this section. Note however that NTE standards apply for any
qualifying operation that occurs during the testing in the same way
that it would during any other in-use testing.
0
89. Amend Sec.  1037.670 by revising paragraph (a) to read as follows:

Sec.  1037.670  Optional CO2 emission standards for tractors at or
above 120,000 pounds GCWR.

    (a) You may certify tractors at or above 120,000 pounds GCWR to the
following CO2 standards instead of the Phase 2
CO2 standards of Sec.  1037.106:

 Table 1 of Paragraph (a) of Sec.   1037.670--Optional CO2 Standards for
     Model Year 2026 and Earlier Tractors Above 120,000 Pounds GCWR
                            (g/ton-mile) \a\
------------------------------------------------------------------------
                                            Model years     Model years
               Subcategory                   2021-2023       2024-2026
------------------------------------------------------------------------
Heavy Class 8 Low-Roof Day Cab..........            53.5            50.8
Heavy Class 8 Low-Roof Sleeper Cab......            47.1            44.5
Heavy Class 8 Mid-Roof Day Cab..........            55.6            52.8
Heavy Class 8 Mid-Roof Sleeper Cab......            49.6            46.9
Heavy Class 8 High-Roof Day Cab.........            54.5            51.4
Heavy Class 8 High-Roof Sleeper Cab.....            47.1            44.2
------------------------------------------------------------------------
\a\ Note that these standards are not directly comparable to the
  standards for Heavy-Haul Tractors in Sec.   1037.106 because GEM
  handles aerodynamic performance differently for the two sets of
  standards.

* * * * *
0
90. Amend Sec.  1037.701 by revising paragraphs (a) and (h) to read as
follows:

Sec.  1037.701  General provisions.

    (a) You may average, bank, and trade emission credits for purposes
of certification as described in this subpart and in subpart B of this
part to show compliance with the standards of Sec. Sec.  1037.105 and
1037.106. Note that Sec.  1037.105(h) specifies standards involving
limited or no use of emission credits under this subpart. Participation
in this program is voluntary.
* * * * *

    (h) See Sec.  1037.740 for special credit provisions that apply for
credits generated under 40 CFR 86.1819-14(k)(7), 40 CFR 1036.615, or
Sec.  1037.615.
* * * * *
0
91. Revise Sec.  1037.705 to read as follows:

Sec.  1037.705  Generating and calculating CO2 emission
credits.

    (a) The provisions of this section apply separately for calculating
CO2 emission credits for each pollutant.
    (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) [middot] PL [middot] Volume [middot]
UL [middot] 10-\6\

Where:

Std = the emission standard associated with the specific regulatory
subcategory (g/ton-mile). For credits generated on all model year
2027 and later vocational vehicles with tailpipe CO2
emissions deemed to be zero under 40 CFR 1037.150(f), use the
emission standard in Sec.  1037.105 that applies for the
compression-ignition multi-purpose subcategory for the corresponding
vehicle weight class.
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,
subject to the exclusions described in paragraph (c) of this
section. 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.

    (c) Compliance with the requirements of this subpart is determined
at the end of the model year by calculating emission credits based on
actual production volumes, excluding any of the following engines:
    (1) Vehicles that you do not certify to the CO2
standards of this part because they are permanently exempted under
subpart G of this part or under 40 CFR part 1068.
    (2) Exported vehicles even if they are certified under this part
and labeled accordingly.
    (3) Vehicles not subject to the requirements of this part, such as
those excluded under Sec.  1037.5.
    (4) Any other vehicles, where we indicate elsewhere in this part
1037 that they are not to be included in the calculations of this
subpart.
0
92. Amend Sec.  1037.710 by revising paragraph (c) to read as follows:

Sec.  1037.710  Averaging.

* * * * *
    (c) If you certify a vehicle family to an FEL that exceeds the
otherwise applicable standard, you must obtain enough emission credits
to offset the vehicle family's deficit by the due date for the final
report required in Sec.  1037.730. The emission credits used to address
the deficit may come from your other vehicle families that generate
emission credits in the same model year (or from later model years as
specified in Sec.  1037.745), from emission credits you have banked
from previous model years, or from emission credits generated in the
same or previous model years that you obtained through trading.
0
93. Amend Sec.  1037.715 by revising paragraph (a) to read as follows:

Sec.  1037.715  Banking.

    (a) Banking is the retention of surplus emission credits by the
manufacturer generating the emission credits for use in future model
years for averaging or trading.
* * * * *
0
94. Amend Sec.  1037.720 by revising paragraph (a) to read as follows:

Sec.  1037.720  Trading.

    (a) Trading is the exchange of emission credits between
manufacturers, or the transfer of credits to another party to retire
them. You may use traded emission credits for averaging, banking, or
further trading transactions. Traded emission credits remain subject to
the averaging-set restrictions based on the averaging set in which they
were generated.
* * * * *
0
95. Amend Sec.  1037.730 by revising paragraphs (b)(4) and (f) to read
as follows:

Sec.  1037.730  ABT reports.

* * * * *
    (b) * * *
    (4) The projected and actual production volumes for the model year
for calculating emission credits. If you changed an FEL during the
model year, identify the actual production volume associated with each
FEL.
* * * * *
    (f) * * *
    (1) If you notify us by the deadline for submitting the final
report that errors mistakenly decreased your balance of emission
credits, you may correct the errors and recalculate the balance of
emission credits. If you notify us that errors mistakenly decreased
your balance of emission credits after the deadline for submitting the
final report, you may correct the errors and recalculate the balance of
emission credits after applying a 10 percent discount to the credit
correction, but only if you notify us within 24 months after the
deadline for submitting the final report. If you report a negative
balance of emission credits, we may disallow corrections under this
paragraph (f)(1).
* * * * *
0
96. Amend Sec.  1037.740 by:
0
a. Removing paragraphs (a)(4) and (5);
0
b. Redesignating paragraph (a)(6) as paragraph (a)(4); and
0
c. Revising paragraphs (b)(1) introductory text and (b)(2).

    The revisions read as follows:

Sec.  1037.740  Restrictions for using emission credits.

* * * * *
    (a) * * *
    (4) Note that other separate averaging sets also apply for emission
credits not related to this part. For example, vehicles certified to
the greenhouse gas standards of 40 CFR part 86, subpart S, comprise a
single averaging set. Separate averaging sets also apply for engines
under 40 CFR part 1036, including engines used in vehicles subject to
this subpart.
    (b) * * *
    (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 part 86, subpart S, 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:
* * * * *
    (2) Credits generated from Phase 2 and Phase 3 vehicles are subject
to all the averaging-set restrictions that apply to other emission
credits.
* * * * *
0
97. Amend Sec.  1037.745 by revising paragraph (a) to read as follows:

Sec.  1037.745  End-of-year CO2 credit deficits.

* * * * *
    (a) Your certificate for a vehicle family for which you do not have
sufficient CO2 credits will not be void if you remedy the
deficit with surplus credits within three model years (this applies
equally for tractors and vocational vehicles). For example, if you have
a credit deficit of 500 Mg for a vehicle family at the end of model
year 2015, you must generate (or otherwise obtain) a surplus of at
least 500 Mg in that same averaging set by the end of model year 2018.
* * * * *
0
98. Amend Sec.  1037.801 by:
0
a. Adding a definition of ``Battery electric vehicle'' in alphabetical
order;
0
b. Removing the definition of ``Box van'';
0
c. Revising the definition of ``Class'';
0
d. Removing the definitions of ``Container chassis'', ``Electric
vehicle'', and ``Flatbed trailer'';
0
e. Adding a definition of ``Fuel cell electric vehicle'' in
alphabetical order;
0
f. Revising the definitions of ``Heavy-duty vehicle'' and ``Heavy-haul
tractor'';
0
g. Adding a definition of ``Hybrid'' in alphabetical order;
0
h. Removing the definitions of ``Hybrid engine or hybrid powertrain''
and ``Hybrid vehicle'';
0
i. Revising the definitions of ``Low rolling resistance tire'',
``Manufacturer'', and ``Model year'';
0
j. Adding a definition of ``Neat'' in alphabetical order;
0
k. Revising the definitions of ``Phase 1'' and ``Phase 2'';
0
l. Adding definitions of ``Phase 3'' and ``Plug-in hybrid electric
vehicle'' in alphabetical order;
0
m. Revising the definitions of ``Preliminary approval'', ``Small
manufacturer'', and ``Standard payload'';
0
n. Removing the definitions of ``Standard tractor'' and ``Tank
trailer''; and
0
o. Revising the definitions of ``Tire rolling resistance level
(TRRL)'', ``Trailer'', ``U.S.-directed production volume'', and
``Vehicle''.
    The additions and revision read as follows:

Sec.  1037.801  Definitions.

* * * * *
    Battery electric vehicle means a motor vehicle powered solely by an
electric motor where energy for the motor is supplied by one or more
batteries that receive power from an external source of electricity.
Note that this definition does not include hybrid vehicles or plug-in
hybrid electric vehicles.
* * * * *
    Class means relating to GVWR classes for vehicles, as follows:
    (1) Class 2b means relating to heavy-duty motor vehicles at or
below 10,000 pounds GVWR.
    (2) Class 3 means relating to heavy-duty motor vehicles above
10,000 pounds GVWR but at or below 14,000 pounds GVWR.
    (3) Class 4 means relating to heavy-duty motor vehicles above
14,000 pounds GVWR but at or below 16,000 pounds GVWR.
    (4) Class 5 means relating to heavy-duty motor vehicles above
16,000 pounds GVWR but at or below 19,500 pounds GVWR.
    (5) Class 6 means relating to heavy-duty motor vehicles above
19,500 pounds GVWR but at or below 26,000 pounds GVWR.
    (6) Class 7 means relating to heavy-duty motor vehicles above
26,000 pounds GVWR but at or below 33,000 pounds GVWR.
    (7) Class 8 means relating to heavy-duty motor vehicles above
33,000 pounds GVWR.
* * * * *
    Fuel cell electric vehicle means a motor vehicle powered solely by
an electric motor where energy for the motor is supplied by hydrogen
fuel cells. Fuel cell electric vehicles may include energy storage from
the fuel cells or from regenerative braking in a battery.
* * * * *
    Heavy-duty vehicle means any motor vehicle that has a GVWR above
8,500 pounds. An incomplete vehicle is also a heavy-duty vehicle if it
has a curb weight above 6,000 pounds or a basic vehicle frontal area
greater than 45 square feet.
    Heavy-haul tractor means a tractor with GCWR greater than or equal
to 120,000 pounds. A heavy-haul tractor is not a vocational tractor in
Phase 2 and Phase 3.
* * * * *
    Hybrid has the meaning given in 40 CFR 1036.801. Note that a hybrid
vehicle is a vehicle with a hybrid powertrain (including a hybrid
engine). This includes plug-in hybrid electric vehicles.
* * * * *
    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.
* * * * *
    Manufacturer has the meaning given in section 216(1) of the Act. In
general, this term includes any person who manufactures or assembles a
vehicle (including an incomplete vehicle) for sale in the United States
or otherwise introduces a new motor vehicle into commerce in the United
States. This includes importers who import vehicles for resale,
entities that manufacture glider kits, and entities that assemble
glider vehicles.
* * * * *
    Model year means one of the following for compliance with this
part. Note that manufacturers may have other model year designations
for the same vehicle for compliance with other requirements or for
other purposes:
    (1) For tractors and vocational vehicles with a date of manufacture
on or after January 1, 2021, model year means the manufacturer's annual
new model production period based on the vehicle's date of manufacture,
where the model year is the calendar year corresponding to the date of
manufacture, except as follows:
    (i) The vehicle's model year may be designated as the year before
the calendar year corresponding to the date of manufacture if the
engine's model year is also from an earlier year. You may ask us to
extend your prior model year certificate to include such vehicles. Note
that Sec.  1037.601(a)(2) limits the extent to which vehicle
manufacturers may install engines built in earlier calendar years.
    (ii) The vehicle's model year may be designated as the year after
the calendar year corresponding to the vehicle's date of manufacture.
For example, a manufacturer may produce a new vehicle by installing the
engine in December 2023 and designating it as a model year 2024
vehicle.
    (2) For Phase 1 tractors and vocational vehicles with a date of
manufacture before January 1, 2021, model year means the manufacturer's
annual new model production period, except as restricted under this
definition and 40 CFR part 85, subpart X. It must include January 1 of
the calendar year for which the model year is named, may not begin
before January 2 of the previous calendar year, and it must end by
December 31 of the named calendar year. The model year may be set to
match the calendar year corresponding to the date of manufacture.
    (i) The manufacturer who holds the certificate of conformity for
the vehicle must assign the model year based on the date when its
manufacturing operations are completed relative to its annual model
year period. In unusual circumstances where completion of your assembly
is delayed, we may allow you to assign a model year one year

earlier, provided it does not affect which regulatory requirements will
apply.
    (ii) Unless a vehicle is being shipped to a secondary vehicle
manufacturer that will hold the certificate of conformity, the model
year must be assigned prior to introduction of the vehicle into U.S.
commerce. The certifying manufacturer must redesignate the model year
if it does not complete its manufacturing operations within the
originally identified model year. A vehicle introduced into U.S.
commerce without a model year is deemed to have a model year equal to
the calendar year of its introduction into U.S. commerce unless the
certifying manufacturer assigns a later date.
* * * * *
    Neat has the meaning given in 40 CFR 1065.1001.
* * * * *
    Phase 1 means relating to the Phase 1 standards specified in
Sec. Sec.  1037.105 and 1037.106. For example, a vehicle subject to the
Phase 1 standards is a Phase 1 vehicle.
    Phase 2 means relating to the Phase 2 standards specified in
Sec. Sec.  1037.105 and 1037.106.
    Phase 3 means relating to the Phase 3 standards specified in
Sec. Sec.  1037.105 and 1037.106.
* * * * *
    Plug-in hybrid electric vehicle means a hybrid vehicle that has the
capability to charge one or more batteries from an external source of
electricity while the vehicle is parked.
* * * * *
    Preliminary approval means approval granted by an authorized EPA
representative prior to submission of an application for certification,
consistent with the provisions of Sec.  1037.210.
* * * * *
    Small manufacturer means a manufacturer meeting the small business
criteria specified in 13 CFR 121.201 for heavy-duty truck manufacturing
(NAICS code 336120). The employee limit applies to the total number
employees for all affiliated companies (as defined in 40 CFR 1068.30).
* * * * *
    Standard payload means the payload assumed for each vehicle, in
tons, for modeling and calculating emission credits, as follows:
    (1) For vocational vehicles:
    (i) 2.85 tons for Light HDV.
    (ii) 5.6 tons for Medium HDV.
    (iii) 7.5 tons for Heavy HDV.
    (2) For tractors:
    (i) 12.5 tons for Class 7.
    (ii) 19 tons for Class 8, other than heavy-haul tractors.
    (iii) 43 tons for heavy-haul tractors.
* * * * *
    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.  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.
* * * * *
    Trailer means a piece of equipment designed for carrying cargo and
for being drawn by a tractor when coupled to the tractor's fifth wheel.
* * * * *
    U.S.-directed production volume means the number of vehicle units,
subject to the requirements of this part, produced by a manufacturer
for which the manufacturer has a reasonable assurance that sale was or
will be made to ultimate purchasers in the United States. Note that
this includes vehicles certified to state emission standards that are
different than the emission standards in this part.
* * * * *
    Vehicle means equipment intended for use on highways that meets at
least one of the criteria of paragraph (1) of this definition, as
follows:
    (1) The following equipment are vehicles:
    (i) A piece of equipment that is intended for self-propelled use on
highways becomes a vehicle when it includes at least an engine, a
transmission, and a frame. (Note: For purposes of this definition, any
electrical, mechanical, and/or hydraulic devices attached to engines
for the purpose of powering wheels are considered to be transmissions.)
    (ii) A piece of equipment that is intended for self-propelled use
on highways becomes a vehicle when it includes a passenger compartment
attached to a frame with one or more axles.
    (2) Vehicles may be complete or incomplete vehicles as follows:
    (i) A complete vehicle is a functioning vehicle that has the
primary load carrying device or container (or equivalent equipment)
attached when it is first sold as a vehicle. Examples of equivalent
equipment would include fifth wheel trailer hitches, firefighting
equipment, and utility booms.
    (ii) An incomplete vehicle is a vehicle that is not a complete
vehicle. Incomplete vehicles may also be cab-complete vehicles. This
may include vehicles sold to secondary vehicle manufacturers.
    (iii) You may ask us to allow you to certify a vehicle as
incomplete if you manufacture the engines and sell the unassembled
chassis components, as long as you do not produce and sell the body
components necessary to complete the vehicle.
* * * * *
0
99. In Sec.  1037.805 amend Table 5 in paragraph (e) by adding an entry
for ``GHG'' in alphabetical order and removing the entry for ``PHEV''
to read as follows:

Sec.  1037.805  Symbols, abbreviations, and acronyms.

* * * * *
    (e) * * *

     Table 5 to Paragraph (e) of Sec.   1037.805--Other Acronyms and
                              Abbreviations
------------------------------------------------------------------------
                  Acronym                              Meaning
------------------------------------------------------------------------

                                * * * * *
GHG.......................................  Greenhouse gas.

                                * * * * *
------------------------------------------------------------------------

* * * * *
0
100. Amend Sec.  1037.810 by:
0
a. Removing paragraph (c)(9);
0
b. Redesignating paragraph (c)(10) as paragraph (c)(9);
0
c. Revising paragraph (d)(4);
0
d. Removing the text ``bb'' in paragraphs (d)(2), (3), and (5) and add,
in their place, the text ``x''; and
0
e. Adding paragraph (e).

    The revision and addition read as follows:

Sec.  1037.810  Incorporation by reference.

* * * * *
    (d) * * *
    (4) Greenhouse gas Emissions Model (GEM) Phase 2, Version 4.0,
April 2022 (``GEM Phase 2, Version 4.0''); IBR approved for Sec. Sec.
1037.150(x); 1037.520.
* * * * *
    (e) UN Economic Commission for Europe, Information Service, Palais
des Nations, CH-1211 Geneva 10, Switzerland; [email protected];
www.unece.org:
    (1) Addendum 22: United Nations Global Technical Regulation, No.
22, United Nations Global Technical Regulation on In-vehicle Battery
Durability for Electrified Vehicles, Adopted April 14, 2022, (``GTR No.
22''); IBR approved for Sec.  1037.115(f).
    (2) [Reserved]

0
101. Revise appendix C of part 1037 to read as follows:

Appendix C of Part 1037--Emission Control Identifiers

    This appendix identifies abbreviations for emission control
information labels, as required under Sec.  1037.135.

Vehicle Speed Limiters
    --VSL--Vehicle speed limiter
    --VSLS--``Soft-top'' vehicle speed limiter
    --VSLE--Expiring vehicle speed limiter
    --VSLD--Vehicle speed limiter with both ``soft-top'' and
expiration
Idle Reduction Technology
    --IRT5--Engine shutoff after 5 minutes or less of idling
    --IRTE--Expiring engine shutoff
Tires
    --LRRA--Low rolling resistance tires (all)
    --LRRD--Low rolling resistance tires (drive)
    --LRRS--Low rolling resistance tires (steer)
Aerodynamic Components
    --ATS--Aerodynamic side skirt and/or fuel tank fairing
    --ARF--Aerodynamic roof fairing
    --ARFR--Adjustable height aerodynamic roof fairing
    --TGR--Gap reducing tractor fairing (tractor to trailer gap)
Other Components
    --ADVH--Vehicle includes advanced hybrid technology components
    --ADVO--Vehicle includes other advanced-technology components
(i.e., non-hybrid system)
    --INV--Vehicle includes innovative (off-cycle) technology
components
    --ATI--Automatic tire inflation system
    --TPMS--Tire pressure monitoring system

0
102. Amend appendix D of part 1037 by revising the appendix heading to
read as follows:

Appendix D of Part 1037--Heavy-Duty Grade Profile for Phase 2 and Phase
3 Steady-State Test Cycles

* * * * *

PART 1054--CONTROL OF EMISSIONS FROM NEW, SMALL NONROAD SPARK-
IGNITION ENGINES AND EQUIPMENT

0
103. The authority citation for part 1054 continues to read as follows:

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

0
104. Amend Sec.  1054.501 by revising paragraph (b)(7) to read as
follows:

Sec.  1054.501  How do I run a valid emission test?

* * * * *
    (b) * * *
    (7) Determine your test fuel's carbon mass fraction, wc,
using a calculation based on fuel properties as described in 40 CFR
1065.655(d); however, you must measure fuel properties for [alpha] and
[beta] rather than using the default values specified in 40 CFR
1065.655(e).
* * * * *

PART 1065--ENGINE-TESTING PROCEDURES

0
105. The authority citation for part 1065 continues to read as follows:

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

0
106. Amend Sec.  1065.210 by revising paragraph (a) to read as follows:

Sec.  1065.210  Work input and output sensors.

    (a) Application. Use instruments as specified in this section to
measure work inputs and outputs during engine operation. We recommend
that you use sensors, transducers, and meters that meet the
specifications in Table 1 of Sec.  1065.205. Note that your overall
systems for measuring work inputs and outputs must meet the linearity
verifications in Sec.  1065.307. We recommend that you measure work
inputs and outputs where they cross the system boundary as shown in
Figure 1 of this section. The system boundary is different for air-
cooled engines than for liquid-cooled engines. If you choose to measure
work before or after a work conversion, relative to the system
boundary, use good engineering judgment to estimate any work-conversion
losses in a way that avoids overestimation of total work. For example,
if it is impractical to instrument the shaft of an exhaust turbine
generating electrical work, you may decide to measure its converted
electrical work. As another example, your engine may include an engine
exhaust electrical heater where the heater is powered by an external
power source. In these cases, assume an electrical generator efficiency
of 0.67 ([eta]=0.67), which is a conservative estimate of the
efficiency and could over-estimate brake-specific emissions. As another
example, you may decide to measure the tractive (i.e., electrical
output) power of a locomotive, rather than the brake power of the
locomotive engine. In these cases, divide the electrical work by
accurate values of electrical generator efficiency ([eta]<1), or assume
an efficiency of 1 ([eta]=1), which would over-estimate brake-specific
emissions. For the example of using locomotive tractive power with a
generator efficiency of 1 ([eta]=1), this means using the tractive
power as the brake power in emission calculations. Do not underestimate
any work conversion efficiencies for any components outside the system
boundary that do not return work into the system boundary. And do not
overestimate any work conversion efficiencies for components outside
the system boundary that do return work into the system boundary. In
all cases, ensure that you are able to accurately demonstrate
compliance with the applicable standards in this chapter. Figure 1
follows:
BILLING CODE 6560-50-P

Figure 1 to paragraph (a) of Sec.  1065.210: Work Inputs, Outputs, and
System Boundaries
[GRAPHIC] [TIFF OMITTED] TP27AP23.074

BILLING CODE 6560-50-C
* * * * *

0
107. Amend subpart C by adding a new center header ``H2 AND
H2O MEASUREMENTS'' after Sec.  1065.250 and adding
Sec. Sec.  1065.255 and 1065.257 under the new center header to read as
follows:

H2 and H2O MEASUREMENTS

Sec.  1065.255  H2 measurement devices.

    (a) General component requirements. We recommend that you use an
analyzer that meets the specifications in Table 1 of Sec.  1065.205.
Note that your system must meet the linearity verification in Sec.
1065.307.
    (b) Instrument types. You may use any of the following analyzers to
measure H2:
    (1) Magnetic sector mass spectrometer.
    (2) Raman spectrometer.
    (c) Interference verification. Certain species can positively
interfere with magnetic sector mass spectroscopy and raman spectroscopy
by causing a response similar to H2. When running the
interference verification for these analyzers, use good engineering
judgment to determine interference species. Note that for raman
spectroscopy interference species are dependent on the H2
infrared absorption band chosen by the instrument manufacturer. For
each analyzer determine the H2 infrared absorption band. For
each H2 infrared adsorption band, determine the interference
species to use in the verification. Use the interference species
specified by the instrument manufacturer or use good engineering
judgment to determine the interference species.

Sec.  1065.257  Fourier transform infrared analyzer for H2O
measurement.

    (a) Component requirements. We recommend that you use an FTIR
analyzer that meets the specifications in Table 1 of Sec.  1065.205.
Note that your system must meet the linearity verification in Sec.
1065.307 using a water generation system that meets the requirements of
Sec.  1065.750(a)(6). Use appropriate analytical procedures for
interpretation of infrared spectra. For example, EPA Test Method 320
(see Sec.  1065.266(b)) and ASTM D6348 (incorporated by reference, see
Sec.  1065.1010) are considered valid methods for spectral
interpretation. You must use heated FTIR analyzers that maintain all
surfaces that are exposed to emissions at a temperature of (110 to 202)
[deg]C.
    (b) Interference verification. Certain species can interfere with
FTIR analyzers by causing a response similar to the water.
    (1) Perform CO2 interference verification for FTIR
analyzers using the procedures of Sec.  1065.357 as CO2 gas
can positively interfere with FTIR analyzers by causing a response
similar to H2O.
    (2) Use good engineering judgment to determine other interference
species for FTIR analyzers. Possible interference species include, but
are not limited to, CO, NO, C2H4, and
C7H8. Perform interference verification using the
procedures of Sec.  1065.357, replacing occurances of CO2
(except for Sec.  1065.357(e)(1)) with the targeted interferent specie.
Note that interference species, with the exception of CO2,
are dependent on the H2O infrared absorption band chosen by
the instrument manufacturer. For each analyzer determine the
H2O infrared absorption band. For each H2O
infrared absorption band, use good engineering judgment to determine
interference species to use in the verification.
0
108. Amend Sec.  1065.266 by revising paragraph (e) as follows:

Sec.  1065.266  Fourier transform infrared analyzer.

* * * * *
    (e) Interference verification. Perform interference verification
for FTIR analyzers using the procedures of Sec.  1065.366. Certain
species can interfere with FTIR analyzers by causing a response similar
to the hydrocarbon species of interest. When running the interference
verification for these analyzers, use interference species as follows:
    (1) The interference species for CH4 are CO2,
H2O, and C2H6.
    (2) The interference species for C2H6 are
CO2, H2O, and CH4.
    (3) The interference species for other measured hydrocarbon species
are CO2, H2O, CH4, and
C2H6.
0
109. Revise the undesignated center heading preceding Sec.  1065.270 to
read as follows:

NOX, N2O, and NH3 MEASUREMENTS
0
110. Add Sec.  1065.277 under the undesignated and newly revised center
header ``NOX, N2O, and NH3
Measurements'' to read as follows:

Sec.  1065.277  NH3 measurement devices.

    (a) General component requirements. We recommend that you use an
analyzer that meets the specifications in Table 1 of Sec.  1065.205.
Note that your system must meet the linearity verification in Sec.
1065.307.
    (b) Instrument types. You may use any of the following analyzers to
measure NH3:
    (1) Nondispersive ultravoilet (NDUV) analyzer.
    (2) Fourier transform infrared (FTIR) analyzer. Use appropriate
analytical procedures for interpretation of infrared spectra. For
example, EPA Test Method 320 (see Sec.  1065.266(b)) and ASTM D6348
(incorporated by reference, see Sec.  1065.1010) are considered valid
methods for spectral interpretation.
    (3) Laser infrared analyzer. Examples of laser infrared analyzers
are pulsed-mode high-resolution narrow band mid-infrared analyzers,
modulated continuous wave high-resolution narrow band mid-infrared
analyzers, and modulated continuous wave high-resolution near-infrared
analyzers. A quantum cascade laser, for example, can emit coherent
light in the mid-infrared region where nitrogen compounds including
NH3 have strong absorption.
    (c) Sampling system. NH3 has a tendency to adsorb to
surfaces that it encounters. Minimize NH3 losses and
sampling artifacts by using sampling system components (sample lines,
prefilters and valves) made of stainless steel or PTFE heated to (110
to 202) [deg]C. If you heat these components to temperatures >=130
[deg]C, use good engineering judgement to minimize NH3
formation due to thermal decomposition and hydrolysis of any DEF
present in the sample gas. Use a sample line that is as short as
practically possible.
    (d) Interference verification. Certain species can positively
interfere with NDUV, FTIR, and laser infrared analyzers by causing a
response similar to NH3. Perform interference verification
for NDUV analyzers using the procedures of Sec.  1065.372, replacing
occurances of NOX with NH3 and interference
species with those listed in paragraph (d)(1) of this section. NDUV
analyzers must have combined interference that is within (0.02.0) [mu]mol/mol. Perform interference verification for FTIR and
laser infrared analyzers using the procedures of Sec.  1065.377. When
running the interference verification for these analyzers, use
interference species as follows:
    (1) For NDUV analyzers, use SO2 and H2O as
the interference species.
    (2) Use good engineering judgment to determine interference species
for FTIR and laser infrared analyzers. Note that interference species,
with the exception of H2O, are dependent on the
NH3 infrared absorption band chosen by the instrument
manufacturer. For each analyzer determine the NH3 infrared
absorption band. For each NH3 infrared absorption band, use
the interference gases specified by the instrument manufacturer or use
good engineering judgment to determine the interference gases to use in
the verification.

0
111. Amend Sec.  1065.315 by revising paragraphs (a)(2) and (3) to read
as follows:

Sec.  1065.315  Pressure, temperature, and dewpoint calibration.

    (a) * * *
    (2) Temperature. We recommend digital dry-block or stirred-liquid
temperature calibrators, with data logging capabilities to minimize
transcription errors. We recommend using calibration reference
quantities that are NIST-traceable within 0.5% uncertainty
of absolute temperature. You may perform linearity verification for
temperature measurement systems with thermocouples, RTDs, and
thermistors by removing the sensor from the system and using a
simulator in its place. Use a NIST-traceable simulator that is
independently calibrated and, as appropriate, cold-junction
compensated. The simulator uncertainty scaled to absolute temperature
must be less than 0.5% of Tmax. If you use this option, you
must use sensors that the supplier states are accurate to better than
0.5% of Tmax compared with their standard calibration curve.
    (3) Dewpoint. We recommend a minimum of three different
temperature-equilibrated and temperature-monitored calibration salt
solutions in containers that seal completely around the dewpoint
sensor. We recommend using calibration reference quantities that are
NIST-traceable within 0.5% uncertainty of absolute dewpoint
temperature.
* * * * *
0
112. Amend subpart D by adding a new center header ``H2O
MEASUREMENTS'' after Sec.  1065.355 and adding Sec. Sec.  1065.357
under the new center header to read as follows:

H2O MEASUREMENTS

Sec.  1065.357  CO2 interference verification for H2O FTIR analyzers.

    (a) Scope and frequency. If you measure H2O using an
FTIR analyzer, verify the amount of CO2 interference after
initial analyzer installation and after major maintenance.
    (b) Measurement principles. CO2 can interfere with an
FTIR analyzer's response to H2O. If the FTIR analyzer uses
compensation algorithms that utilize measurements of other gases to
meet this interference verification, simultaneously conduct these other
measurements to test the compensation algorithms during the analyzer
interference verification.
    (c) System requirements. An H2O FTIR analyzer must have
a CO2 interference that is within (0.00.4) mmol/
mol, though we strongly recommend a lower interference that is within
(0.00.2) mmol/mol.
    (d) Procedure. Perform the interference verification as follows:
    (1) Start, operate, zero, and span the H2O FTIR analyzer
as you would before an emission test.
    (2) Use a CO2 span gas that meets the specifications of
Sec.  1065.750 and a concentration that is approximately the maximum
CO2 concentration expected during emission testing.
    (3) Introduce the CO2 test gas into the sample system.
    (4) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the transfer line and to
account for analyzer response.
    (5) While the analyzer measures the sample's concentration, record
30 seconds of sampled data. Calculate the arithmetic mean of this data.
The analyzer meets the interference verification if this value is
within (0.0  0.4) mmol/mol.
    (e) Exceptions. The following exceptions apply:
    (1) You may omit this verification for CO2 for engines
operating on fuels other than carbon-containing fuels.
    (2) You may omit this verification if you can show by engineering
analysis that for your H2O sampling system and your
emission-calculation procedures, the CO2 interference for
your H2O FTIR analyzer always affects your brake-specific
emission results within 0.5% of each of the applicable
standards in this chapter. This specification also applies for vehicle
testing, except that it relates to emission results in g/mile or g/
kilometer.
    (3) You may use an H2O FTIR analyzer that you determine
does not meet this verification, as long as you try to correct the
problem and the measurement deficiency does not adversely affect your
ability to show that engines comply with all applicable emission
standards.
0
113. Amend Sec.  1065.360 by revising paragraphs (a)(4), (b), (d)
introductory text, and (d)(12) to read as follows:

Sec.  1065.360  FID optimization and verification.

    (a) * * *
    (4) You may determine the methane (CH4) and ethane
(C2H6) response factors as a function of the
molar water concentration in the raw or diluted exhaust. If you choose
the option in this paragraph (a)(4), generate and verify the humidity
level (or fraction) as described in Sec.  1065.365(g).
    (b) Calibration. Use good engineering judgment to develop a
calibration procedure, such as one based on the FID-analyzer
manufacturer's instructions and recommended frequency for calibrating
the FID. Alternately, you may remove system components for off-site
calibration. For a FID that measures THC, calibrate using
C3H8 calibration gases that meet the
specifications of Sec.  1065.750. For a FID that measures
CH4, calibrate using CH4 calibration gases that
meet the specifications of Sec.  1065.750. We recommend FID analyzer
zero and span gases that contain approximately the flow-weighted mean
concentration of O2 expected during testing. If you use a
FID to measure CH4 downstream of a nonmethane cutter (NMC),
you may calibrate that FID using CH4 calibration gases with
the NMC. Regardless of the calibration gas composition, calibrate on a
carbon number basis of one (C1). For example, if you use a
C3H8 span gas of concentration 200 [mu]mol/mol,
span the FID to respond with a value of 600 [mu]mol/mol. As another
example, if you use a CH4 span gas with a concentration of
200 [mu]mol/mol, span the FID to respond with a value of 200 [mu]mol/
mol.
* * * * *
    (d) THC FID CH4 response factor determination. This procedure is
only for FID analyzers that measure THC. Since FID analyzers generally
have a different response to CH4 versus
C3H8, determine the THC-FID analyzer's
CH4 response factor, RFCH4[THC-FID], after FID
optimization. Use the most recent RFCH4[THC-FID] measured
according to this section in the calculations for HC determination
described in Sec.  1065.660 to compensate for CH4 response.
Determine RFCH4[THC-FID] as follows, noting that you do not
determine RFCH4[THC-FID] for FIDs that are calibrated and
spanned using CH4 with an NMC:
* * * * *
    (12) You may determine the response factor as a function of molar
water concentration and use this response factor to account for the
CH4 response for NMHC determination described in Sec.
1065.660(b)(2)(iii). If you use this option, humidify the
CH4 span gas as described in Sec.  1065.365(g) and repeat
the steps in paragraphs (d)(7) through (9) of this section until
measurements are complete for each setpoint in the selected range.
Divide each mean measured CH4 concentration by the recorded
span concentration of the CH4 calibration gas, adjusted for
water content, to determine the FID analyzer's CH4 response
factor, RFCH4[THC-FID]. Use the CH4 response
factors at the different setpoints to create a functional relationship
between response factor and molar water concentration,

downstream of the last sample dryer if any sample dryers are present.
Use this functional relationship to determine the response factor
during an emission test.
* * * * *
0
114. Revise Sec.  1065.365 to read as follows:

Sec.  1065.365  Nonmethane cutter penetration fractions and NMC FID
response factors.

    (a) Scope and frequency. If you use a FID analyzer and a nonmethane
cutter (NMC) to measure methane (CH4), determine the NMC's
penetration fractions of CH4, PFCH4, and ethane
(C2H6), PFC2H6. As detailed in this
section, these penetration fractions may be determined as a combination
of NMC penetration fractions and FID analyzer response factors,
depending on your particular NMC and FID analyzer configuration.
Perform this verification after installing the NMC. Repeat this
verification within 185 days of testing to verify that the catalytic
activity of the NMC has not deteriorated. Note that because NMCs can
deteriorate rapidly and without warning if they are operated outside of
certain ranges of gas concentrations and outside of certain temperature
ranges, good engineering judgment may dictate that you determine an
NMC's penetration fractions more frequently.
    (b) Measurement principles. A NMC is a heated catalyst that removes
nonmethane hydrocarbons from an exhaust sample stream before the FID
analyzer measures the remaining hydrocarbon concentration. An ideal NMC
would have a CH4 penetration fraction, PFCH4, of
1.000, and the penetration fraction for all other nonmethane
hydrocarbons would be 0.000, as represented by PFC2H6. The
emission calculations in Sec.  1065.660 use the measured values from
this verification to account for less than ideal NMC performance.
    (c) System requirements. We do not limit NMC penetration fractions
to a certain range. However, we recommend that you optimize an NMC by
adjusting its temperature to achieve a PFC2H6 <0.02, as
determined by paragraphs (d), (e), or (f) of this section, as
applicable, using dry gases. If we use an NMC for testing, it will meet
this recommendation. If adjusting NMC temperature does not result in
achieving this recommendation, we recommend that you replace the
catalyst material. Use the most recently determined penetration values
from this section to calculate HC emissions according to Sec.  1065.660
and Sec.  1065.665 as applicable.
    (d) Procedure for a FID calibrated with the NMC. The method
described in this paragraph (d) is recommended over the procedures
specified in paragraphs (e) and (f) of this section and required for
any gaseous-fueled engine, including dual-fuel and flexible-fuel
engines. For any gaseous-fueled engine, including dual-fuel and
flexible-fuel engines, you must determine the combined CH4
response factor and penetration fraction, RFPFCH4[NMC-FID],
and combined C2H6 response factor and penetration
fraction, RFPFC2H6[NMC-FID], as a function of the molar
water concentration in the raw or diluted exhaust as described in
paragraphs (d)(9) and (g) of this section. Note that
RFPFCH4[NMC-FID] is set equal to 1.0 only for zero molar
water concentration. For any other engine you may use the same
procedure, or you may set RFPFCH4[NMC-FID] equal to 1.0 and
determine RFPFC2H6[NMC-FID] at zero molar water
concentration. Generate and verify the humidity generation as described
in paragraph (g) of this section.
    (1) Select CH4 and C2H6 analytical
gas mixtures and ensure that both mixtures meet the specifications of
Sec.  1065.750. Select a CH4 concentration that you would
use for spanning the FID during emission testing and select a
C2H6 concentration that is typical of the peak
NMHC concentration expected at the hydrocarbon standard or equal to the
THC analyzer's span value. For CH4 analyzers with multiple
ranges, perform this procedure on the highest range used for emission
testing.
    (2) Start, operate, and optimize the NMC according to the