Document ID: EPA-HQ-OAR-2019-0307-0107
Agency: epa
Document Type: Rule
Title: Improvements for Heavy-Duty Engine and Vehicle Test Procedures
Posted Date: 2022-07-28T04:00Z

[Federal Register Volume 87, Number 144 (Thursday, July 28, 2022)]
[Rules and Regulations]
[Pages 45257-45267]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-16031]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 1036 and 1037

[EPA-HQ-OAR-2019-0307; FRL-7423.1-01-OAR]
RIN 2060-AV21

Improvements for Heavy-Duty Engine and Vehicle Test Procedures

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This final rule includes corrections, clarifications, 
additional flexibilities, and adjustment factors to improve the 
Greenhouse gas Emissions Model (GEM) compliance tool for heavy-duty 
vehicles while more closely matching the outputs produced by the 
original GEM version 3.0 that was used to establish the CO2 
standards for Model Years 2021 and later in the 2016 Heavy-duty Phase 2 
final rule. Given the nature of this rule, there will be neither 
significant environmental impacts nor significant economic impacts.

DATES: This final rule is effective on August 29, 2022. The 
incorporation by reference of certain publications listed in this 
regulation is approved by the Director of the Federal Register as of 
August 29, 2022.

ADDRESSES: 
    Docket: EPA has established a docket for this action under Docket 
ID No. EPA-HQ-OAR-2019-0307. Publicly available docket materials are 
available either electronically at www.regulations.gov or in hard copy 
at Air and Radiation Docket and Information Center, EPA Docket Center, 
EPA/DC, EPA WJC West Building, 1301 Constitution Ave. NW, Room 3334, 
Washington, DC. Certain material, such as copyrighted material, is not 
placed on the internet and will be publicly available only at the EPA 
Docket Center. For further information on EPA Docket Center services 
and the current status, please visit us online at www.epa.gov/dockets.
    Public participation: Docket: All documents in the docket are 
listed on the www.regulations.gov website. Although listed in the 
index, some information is not publicly available, e.g., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the internet 
and will be publicly available only in hard copy form through the EPA 
Docket Center at the location listed in the ADDRESSES section of this 
document.

FOR FURTHER INFORMATION CONTACT: Amy Kopin, Office of Transportation 
and Air Quality, Assessment and Standards Division, Environmental 
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; 
telephone number: (734) 214-4173; email address: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
II. Greenhouse Gas Emissions Model (GEM) Background
III. GEM 4.0
IV. Updates to Test Procedures
V. Statutory Authority and Executive Order Reviews

I. General Information

Does this action apply to me?

    This action relates to companies that manufacture or sell new 
heavy-duty engines and vehicles as defined under EPA's CAA 
regulations.\1\ Regulated categories and entities include the 
following:
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    \1\ ``Heavy-duty engine'' and ``heavy-duty vehicle'' are defined 
in 40 CFR 1037.801.

------------------------------------------------------------------------
       NAICS codes \a\                        NAICS titles
------------------------------------------------------------------------
333618, 336111, 336112,        Other Engine Equipment Manufacturing,
 336120, 336211, 336999.        Automobile Manufacturing, Light Truck
                                and Utility Vehicle Manufacturing, Heavy
                                Duty Truck Manufacturing, Motor Vehicle
                                Body Manufacturing, All Other
                                Transportation Equipment Manufacturing.
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\a\ North American Industry Classification System (NAICS).

    This list is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. If you have questions regarding the applicability of this 
action to a particular entity, consult the person listed in the FOR 
FURTHER INFORMATION CONTACT section.

What action is the Agency taking?

    This action amends the procedures for demonstrating compliance with 
the CO2 emission standards for heavy-duty highway engines 
and vehicles with several corrections, clarifications, and additional 
flexibilities.
    EPA published a proposed rule on May 12, 2020 (85 FR 28153) 
(``Technical Amendments proposed rule''). EPA issued a corresponding 
final rulemaking (``Technical Amendments final rule'') relating to most 
revisions in the Technical Amendments proposed rule (86 FR 34308, June 
29, 2021). Additionally, for the amendments in this final action, EPA 
published a supplemental notice of proposed rulemaking (``Technical 
Amendments supplemental proposed rule'') with additional amendments for 
certain aspects of the modeling parameters used for certifying vehicles 
(86 FR 34189, June 29, 2021).

What are the incremental costs and benefits of this action?

    This action is limited in scope and does not have significant 
economic or environmental impacts. EPA has therefore not estimated the 
potential costs or benefits of this final rule.

II. Greenhouse Gas Emissions Model (GEM) Background

    The Greenhouse gas Emissions Model (GEM) is a computer application 
that estimates the greenhouse gas (GHG) emissions and fuel efficiency 
performance of specific aspects of heavy-duty vehicles. GEM uses 
several vehicle-specific inputs, such as engine fuel maps, aerodynamic 
drag coefficients, and vehicle weight ratings, to simulate vehicle and 
engine operation and model the amount of CO2 emitted over 
multiple duty cycles for tractors and vocational vehicles. The 
resulting CO2 values over these cycles are weighted by GEM 
to provide a Default FEL CO2 Emissions value. GEM version 
3.0 was used to set standards in the Greenhouse Gas Emissions and Fuel 
Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles 
Phase 2 (``Phase 2'') rulemaking (81 FR 73478). For purposes of 
determining compliance, Default FEL CO2 Emissions

[[Page 45258]]

from GEM are compared to the applicable Phase 2 vehicle standard.
    In the Technical Amendments proposed rule, we proposed several 
amendments to GEM 3.0, including corrections, clarifications, and 
additional flexibilities in a revised version of the model, GEM 3.5 (85 
FR 28145). EPA also requested comment on whether any differences in GEM 
output values resulting from changes to the model would impact the 
effective stringency of the program and, if so, whether EPA should 
revise the GEM model itself or address such impacts via regulations 
(see 85 FR 28145). Comments received in response to the Technical 
Amendments proposed rule supported most of the proposed updates to GEM 
and requested additional revisions to further improve the model.\2\ The 
California Air Resources Board (CARB) provided comment stating the 
importance of GEM results being consistent with the 2016 Phase 2 final 
rule program standards to avoid affecting program stringency. CARB 
recommended that EPA revise GEM in order to ensure stringency is 
maintained.\3\
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    \2\ See ``Improvements for Heavy-Duty Engine and Vehicle Test 
Procedures, and other Technical Amendments Response to Comments'', 
Publication Number: EPA-420-R-20-026, December 2020. Chapter 2 of 
the Response to Comments provides additional details on the 
amendments, clarifications requested by commenters, and our 
responses to most of the comments to the NPRM.
    \3\ California Air Resources Board, Docket number EPA-HQ-OAR-
2019-0207-0030.
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    After considering the comments received, EPA applied further 
changes to GEM 3.5 and released in October of 2020 a new development 
version of GEM, GEM 3.7, to the public for download and review by 
stakeholders to evaluate and assess the performance of this revised 
model. GEM 3.7 incorporated some corrections and improvements relative 
to the proposed version GEM 3.5, as noted in the corresponding 
memorandum in the rulemaking docket (October 23, 2020 memorandum).\4\
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    \4\ Nelson, Brian. Memorandum to Docket EPA-HQ-OAR-2019-0307. 
``Development version of GEM and adjustment factors''. October 23, 
2020. Docket number EPA-HQ-OAR-2019-0307-0083. Also available 
online: https://www3.epa.gov/otaq/gem-p2v3.7-release-memo-2020-10-23.pdf.
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    While evaluating GEM 3.7, we found differences in the output values 
for some tractor and vocational vehicles compared to the output values 
from GEM 3.0 (the version used to set the Phase 2 CO2 
standards). To understand the differences between GEM 3.0 and GEM 3.7, 
we replicated the process used in 2016 to determine the numerical level 
of the Phase 2 standards. Without an adjustment to the resulting GEM 
output value, these differences in GEM output values when compared to 
the Phase 2 final rule could be considered an effective change in 
stringency. In light of GEM 3.7 output differences and considering 
CARB's comment, we identified adjustment factors in the October 23, 
2020 docket memorandum that could be applied to the unrounded GEM 3.7 
output values to better ensure effective stringency of the standards is 
maintained.\5\ The Truck and Engine Manufacturers Association (EMA) 
requested additional time for its members to review the potential 
updates to the model in GEM 3.7 and evaluate the impact of the 
adjustment factors made available.\6\
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    \5\ Id.
    \6\ Charmley, Bill. Memorandum to Docket EPA-HQ-OAR-2019-0307. 
``EPA discussions with the Truck and Engine Manufacturers 
Association, and with the California Air Resources Board, regarding 
Highway Heavy-Duty Technical Amendments.'' December 14, 2020. Docket 
Number EPA-HQ-OAR-2019-0307-0092.
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    In the Technical Amendments final rule, EPA finalized a revised 
version of GEM (GEM 3.5.1) that included the changes proposed in GEM 
version 3.5 as well as changes that corrected three errors in the GEM 
3.5 code and did not include any adjustment factors. GEM 3.5.1 included 
the following updates to GEM 3.5:
     Corrected duty cycle weighting factors for vocational 
vehicles in the Heavy Heavy-Duty Multipurpose subcategory.
     Corrected an idle map error when the cycle average engine 
fuel mapping procedure is used for all three drive cycles.
     Corrected a functional error that unnecessarily required 
manufacturers to include transmission power loss data when using the 
option to enter a unique (instead of default) k-factor for the torque 
converter.
    In the Technical Amendments supplemental proposed rule, EPA 
proposed to revise GEM through additional changes in an updated version 
of GEM (GEM 3.8 which was identical to GEM 3.7, except that GEM 3.8 
included changes to the GEM HIL model). This rule also proposed to 
revise GEM's test procedures to include adjustment factors and to 
improve the GEM compliance tool for heavy-duty vehicles while more 
closely matching the outputs produced by the original GEM version 3.0 
that was used to establish the CO2 standards for Model Years 
2021 and later in the 2016 Heavy-duty Phase 2 final rule. The Technical 
Amendments supplemental proposed rule also proposed that GEM 3.5.1 
would be limited to use for model year (``MY'') 2021 only, except where 
MY 2021 data could be used for carryover requests for certificates of 
conformity for MY 2022 and future years for qualifying vehicles under 
Sec.  1036.235(d) (but in such circumstances EPA proposed that 
manufacturers would still be required to use GEM 3.8 for end-of-year 
reporting for MY 2022 and future years).\7\
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    \7\ See 86 FR 34192.
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    After considering the comments received in response to our 
Technical Amendments supplemental proposed rule, EPA applied further 
potential changes to GEM 3.8 and released a new development version of 
GEM, GEM 3.9, in December 2021. EPA also updated the adjustment factors 
released with the GEM 3.8 version to accommodate the changes made in 
the development of GEM 3.9. GEM 3.9 also included an updated method of 
creating these adjustment factors using unrounded GEM results instead 
of using the rounded GEM results as was done with GEM 3.8. GEM 3.9 was 
released to the public for download and review by stakeholders to 
evaluate and assess the performance of this revised model. GEM 3.9 
incorporated corrections and improvements relative to GEM 3.8, as noted 
in the corresponding memorandum in the rulemaking docket.\8\ Table 1 
summarizes the history of the different versions of GEM.
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    \8\ Nelson, Brian. Memorandum to Docket EPA-HQ-OAR-2019-0307. 
``Development version of GEM3.9 and adjustment factors''. December 
20, 2021. Docket Number EPA-HQ-OAR-2019-0307-0092. Available online: 
https://www.epa.gov/system/files/documents/2021-12/gem-v3.9-adjust-factors-memo-2021-12-20-.pdf.

                    Table 1--History of GEM Releases
------------------------------------------------------------------------
               Version                              History
------------------------------------------------------------------------
GEM 3.0..............................  Original official version
                                        finalized in the 2016 Phase 2
                                        final rule.
GEM 3.5..............................  Unofficial version proposed in
                                        the Technical Amendments
                                        proposed rule.
GEM 3.5.1............................  Version finalized in the
                                        Technical Amendments final rule.

[[Page 45259]]

 
GEM 3.7..............................  Unofficial version released
                                        between the Technical Amendments
                                        proposed and final rules.
GEM 3.8..............................  Unofficial version proposed in
                                        the Technical Amendments
                                        supplemental proposed rule.
GEM 3.8 HIL..........................  Version finalized in the
                                        Technical Amendments final rule
                                        for powertrain testing defined
                                        in 40 CFR 1037.550.
GEM 3.9..............................  Unofficial version released after
                                        the Technical Amendments
                                        supplemental proposed rule.
------------------------------------------------------------------------

III. GEM 4.0

A. Updates to GEM

    This final rule further revises GEM and includes GEM adjustment 
factors within the model. Applying the adjustment factors within GEM 
will help reduce potential process errors.
    We are adopting GEM version 4.0.9 10 This updated 
version of the model allows additional compliance flexibilities and 
improves the vehicle simulation by incorporating the following 
improvements relative to GEM 3.5.1:
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    \9\ Greenhouse gas Emissions Model (GEM) Phase 2, Version 4.0, 
January 2022. A working version of this software is also available 
for download at https://www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty.
    \10\ The changes summarized in the following listed items 13,14, 
15, and 16 are changes that were made to GEM version 4.0 relative to 
GEM version 3.9.
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    1. Changed limits on engine input to allow small negative torque 
inputs.
    2. Corrected how GEM adjusts the idle fueling of the transient 
cycle by using the same idle duration time both for subtracting the 
idle fuel rate from the transient cycle average engine fuel map and for 
adding back in the simulated idle fuel rate.
    3. Added an option for vocational vehicles to input a value for 
neutral coasting in GEM and amend the related test procedure in 40 CFR 
1037.520(j)(1).
    4. Corrected manual and automated manual transmissions to perform 
clutched upshifts for Heavy Heavy-Duty Vehicles (HDV).
    5. Allow input files from previous versions of GEM.
    6. Changed GEM to not merge drive idle fuel map with default 
steady-state fuel map.
    7. Corrected errors with the default fuel maps that are used for 
Custom Chassis vehicles.
    8. Changed the regression model that is used for interpolating the 
cycle average fuel maps for the cruise cycles to improve the accuracy 
and representativeness of the regression model.\11\
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    \11\ Sanchez, James. Memorandum to Docket: EPA-HQ-OAR-2019-0307. 
GEM Regression Model for Cycle-Average Cruise Cycles. March 11, 
2022.
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    9. Changed GEM to account for the emissions performance of stop-
start automatic and engine shutdown systems (AESS) technologies when 
the powertrain test procedure is used to create the fuel map input 
file.
    10. Applies mass of CO2 to gallons of fuel conversion 
factor by combustion type instead of fuel type.
    11. Includes a change to the carbon mass fraction for E85 to the 
value in Table 1 of 40 CFR 1036.530.
    12. Includes a 5% tolerance for declared idle target speed vs idle 
fuel map test points.
    13. Changed how GEM models powertrain accessory work for 55/65 mph 
cruise cycles and idle cycles.\12\
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    \12\ Sanchez, James. Memorandum to Docket: EPA-HQ-OAR-2019-0307. 
Modeling of Powertrain Accessory Work in GEM. March 11, 2022.
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    a. 55/65 mph cruise cycles: GEM uses the slope from the fuel-
versus-work regression of the cruise cycle average fuel map to account 
for emissions from accessory work
    b. Idle cycles: GEM uses the slope from the fuel-versus-work 
regression of the transient cycle average fuel map to account for 
emissions from accessory work
    14. Changed GEM output label ``FEL CO2 Emissions'' to 
``Default FEL CO2 Emissions'' and ``FEL Consumption'' to 
``Default FEL Consumption''.
    15. Changed units of GEM tire rolling resistance input from ``kg/
t'' to ``N/kN''.
    16. Updated GEM hardware in the loop (HIL) to better reflect 
operation during transmission shifting.
    To ensure that these changes we are finalizing into GEM 4.0 do not 
change the effective stringency of the Phase 2 CO2 
standards, we are adopting adjustment factors in GEM 4.0. In GEM 4.0, 
EPA has updated the adjustment factors released with the GEM 3.8 
version to accommodate the changes made in the development of GEM 4.0 
and the updated method of creating these factors using unrounded GEM 
results (versus using the rounded GEM results as was done with GEM 
3.8). The revised adjustment factors are included below and are a 
function of regulatory subcategory and the vehicle model year (i.e., MY 
2021-2023; MY 2024-2026; and MY 2027 and later).\13\ One exception is 
tractors with automatic transmission. For tractors with automatic 
transmissions, GEM 4.0 includes an adjustment factor of zero.\14\ In 
GEM 4.0, the adjustment factors in Table 2 are applied to the composite 
GEM result within the program itself using the following equation.
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    \13\ Table 2 summarizes the adjustment factors included in GEM 
4.0. Section III of the preamble discusses for which model years GEM 
4.0 applies.
    \14\ Chapter 1.6 of the Response to Comments provides additional 
details on why GEM 4.0 includes an adjustment factor of zero for 
tractors with automatic transmissions.
[GRAPHIC] [TIFF OMITTED] TR28JY22.014

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Where:

eCO2 = unrounded composite CO2 emissions from GEM.
    AF = the applicable adjustment factor from Table 1.

                                       Table 2--GEM 4.0 Adjustment Factors
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                                                                            Adjustment factor
                                                        --------------------------------------------------------
                 Regulatory subcategory                    MY 2021-2023      MY 2024-2026     MY 2027-and-later
                                                              vehicle           vehicle            vehicle
----------------------------------------------------------------------------------------------------------------
Class 7 Day Cab Low Roof...............................           -0.0107           -0.0094              -0.0097
Class 7 Day Cab Mid Roof...............................           -0.0105           -0.0091              -0.0091
Class 7 Day Cab High Roof..............................           -0.0090           -0.0094              -0.0093
Class 8 Day Cab Low Roof...............................           -0.0062           -0.0074              -0.0069
Class 8 Sleeper Cab Low Roof...........................           -0.0010           -0.0013              -0.0010

[[Page 45260]]

 
Class 8 Day Cab Mid Roof...............................           -0.0064           -0.0070              -0.0065
Class 8 Sleeper Cab Mid Roof...........................           -0.0010           -0.0011              -0.0010
Class 8 Day Cab High Roof..............................           -0.0061           -0.0071              -0.0067
Class 8 Sleeper Cab High Roof..........................           -0.0011           -0.0010              -0.0009
Class 8 Heavy Haul.....................................           -0.0068           -0.0067              -0.0070
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Multi-Purpose Light HDV Compression-ignition...........                          -0.0006
Regional Light HDV Compression-ignition................                           0.0005
Urban Light HDV Compression-ignition...................                           0.0000
Multi-Purpose Medium HDV Compression-ignition..........                          -0.0030
Regional Medium HDV Compression-ignition...............                           0.0008
Urban Medium HDV Compression-ignition..................                          -0.0036
Multi-Purpose Heavy HDV Compression-ignition...........                           0.0097
Regional Heavy HDV Compression-ignition................                           0.0006
Urban Heavy HDV Compression-ignition...................                           0.0132
Multi-Purpose Light HDV Spark-ignition.................                           0.0001
Regional Light HDV Spark-ignition......................                           0.0008
Urban Light HDV Spark-ignition.........................                           0.0011
Multi-Purpose Medium HDV Spark-ignition................                           0.0015
Regional Medium HDV Spark-ignition.....................                           0.0005
Urban Medium HDV Spark-ignition........................                           0.0028
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School bus.............................................                -0.0031                           -0.0030
Motor home.............................................                0.0001                             0.0001
Coach bus..............................................                0.0018                             0.0019
Other bus..............................................                0.0132                             0.0135
Refuse hauler..........................................                0.0124                             0.0126
Concrete mixer.........................................                0.0124                             0.0125
Mixed-use vehicle......................................                0.0124                             0.0125
Emergency vehicle......................................                0.0122                             0.0124
----------------------------------------------------------------------------------------------------------------

B. Allowable Versions of GEM for Certification and Compliance

    We are incorporating by reference into the regulations the revised 
version of the model, GEM 4.0. GEM 4.0 is adopted upon the effective 
date of this final rule to demonstrate compliance with the Phase 2 
standards under 40 CFR 1037.520, including end-of-year reporting. Due 
to the timing of this final rule, we are applying the requirement to 
use GEM version 4.0 starting with MY 2024. EPA is also finalizing 
provisions to allow for an orderly transition to the updated GEM 
version. For MY 2022 through 2023, manufacturers may also use GEM 3.0 
or GEM 3.5.1 under interim provision Sec.  1037.150(bb) to demonstrate 
compliance with the Phase 2 standards. Manufacturers may use different 
versions of GEM for different families within each model year before MY 
2024. Manufacturers may also change versions of GEM for MY 2022 and 
2023 vehicle families between the initial application for certification 
and submission of the final report after the end of the model year; 
however, manufacturers would need to document any changes in the GEM 
version for MY 2022 and 2023 vehicle families by submitting a running 
change as an amendment to the application for certification under Sec.  
1036.225. We also note that, once a manufacturer amends an application 
for certification to rely on GEM 4.0 or submits a new application that 
relies on GEM 4.0 under interim provision Sec.  1037.150(bb), the 
manufacturer may not revert back to an earlier version of GEM for that 
vehicle family.
    Changing to a different version of GEM for MY 2021 is a special 
case. Manufacturers have certified all their MY 2021 families using 
either GEM 3.0 or GEM 3.5.1. However, the model year has already ended. 
The flexibility to use a different official version of GEM, including 
GEM 4.0, therefore applies only for the end-of-year report that is due 
in September 2022. We are also adopting this flexibility only for 
vehicle families certified to the standards for custom chassis in Sec.  
1037.105(h). We are providing this flexibility for vehicle families 
meeting standards for custom chassis because we determined that there 
was an unintended increase in effective stringency for those vehicles 
in GEM 3.5.1. Manufacturers don't need the flexibility to change GEM 
versions for other families because they did not have this unexpected 
impact in GEM 3.5.1 and they have already closed out their model year. 
Finally, manufacturers must document any change in the version of GEM 
for end-of-year reporting in the submission of those end-of-year 
reports.
    The requirement to start using GEM 4.0 also applies starting with 
MY 2024 for manufacturers generating fuel maps using either engine 
testing or powertrain testing. Powertrain fuel mapping procedures are 
including in the Hardware-in-Loop (HIL) model that is part of GEM. 
Under interim provision 40 CFR 1036.150(r), manufacturers may certify 
in MY 2021 through 2023 with fuel maps generated using GEM 3.0, GEM 
3.5.1, GEM HIL 3.8, or GEM 4.0. Manufacturers may continue to certify 
in MY 2024 and later using fuel maps generated using earlier GEM 
versions in cases where the manufacturer qualifies for carryover 
certification. If we conduct or direct the manufacturer to do 
confirmatory testing, selective enforcement audits, or in-use testing 
of a set of engine or powertrain fuel maps, we will use or direct the 
manufacturer to use the same version of GEM that the manufacturer used 
to create those fuel maps. We intend to review the manufacturer's use 
of this carryover allowance going forward; we may consider in a future 
rulemaking whether

[[Page 45261]]

there is a continued need for manufacturers to use fuel maps generated 
using these transitional versions of GEM.

IV. Updates to Test Procedures

    We are finalizing revisions to the regulatory text in 40 CFR parts 
1036 and 1037 to clarify or make changes to the test procedures used to 
create inputs for GEM.
    We are finalizing changes to 40 CFR 1036.503(b)(4) to address the 
handling and use of automatic stop-start systems and automatic engine 
shutdown systems when performing powertrain fuel map testing under 40 
CFR 1037.550. Finalization of the Phase 2 technical amendments left it 
unclear with respect to how these systems and accessory loads were 
handled by GEM for powertrain testing. The revisions require that any 
engine stop-start and automatic shutdown systems be disabled prior to 
performing powertrain testing, as the effects of these systems will be 
handled by GEM, when GEM is used to determine the emissions of the 
vehicle. We are also clarifying the accessory load that should be used 
by primary intended service class during the powertrain test for hybrid 
engines so that hybrid engines are tested with the same accessory loads 
that are used for conventional engines. The power representing the 
accessory load added for Light HDV, Medium HDV, and Heavy HDV is 1.5, 
2.5, and 3.5 kW, respectively.
    In GEM 3.5.1, finalized in the Technical Amendments final rule, we 
included updates to handle point deletion in GEM but did not update our 
regulation, which required the prior approach of manual removal of such 
points. Consistent with this prior change to having GEM handle point 
deletion (now in GEM 4.0), we are now removing that requirement in 40 
CFR 1036.535(d)(3), for steady-state fuel maps used for cycle-average 
fuel mapping of the highway cruise cycles, that requires manual removal 
of the points from the default map that are below 115% of the maximum 
speed and 115% of the maximum torque of the boundaries of the points 
measured in 40 CFR 1036.535(d)(1). See Section 1.7 of the Response to 
Comments document for further discussion.
    We are finalizing changes to GEM inputs determined in 40 CFR 
1036.540(e) for cycle-average fuel maps for the cruise cycles. This 
revision changes the cruise cycle fuel map outputs from N/V (powertrain 
rotational speed divided by vehicle speed in revolutions per meter as 
defined specifically in 40 CFR part 1036), fuel mass consumption, and 
work to average engine speed, average engine torque, fuel mass 
consumption, and work. We are also adding a new vehicle configuration 
output matrix for cruise cycles to denote the differences that now 
exist for the testing outputs needed for GEM for transient and cruise 
cycles. These changes align the test procedure with changes to the 
regression model in GEM that is used for interpolating the cycle 
average fuel maps for the cruise cycles. The change in the regression 
model aligns the GEM results when the cycle-average method is used for 
the cruise cycles with the GEM results when the standard engine fuel 
mapping procedure is used (40 CFR 1036.503(b)(1)).
    We are finalizing changes in 40 CFR 1037.510 to correct the example 
problem that solves for eCO2comp. The value for 
vmoving was correctly listed as 38.41 mi/hr in the example; 
however, the value entered into the example problem of 41.93 mi/hr was 
in error. The change updates the example problem to the correct value.
    We are finalizing changes in 40 CFR 1037.520(j)(1) to allow the 
input value of 1.5 in GEM o vocational vehicles that include 
intelligent controls (predictive cruise control). This change 
recognizes the CO2 benefit of this technology in GEM for 
vocational vehicles, which was previously only allowed for tractors.
    We are finalizing an amendment in 40 CFR 1037.550(a)(8) to clarify 
that accessory loads should not be included in powertrain testing when 
conducting a powertrain test to generate inputs to GEM if torque is 
measured at the axle input shaft or wheel hubs. We are also finalizing 
changes to 40 CFR 1037.550(f) to clarify for hybrid engines that GEM 
must be configured with the applicable accessory load as specified in 
40 CFR 1036.503. We are also finalizing a change at 40 CFR 
1037.550(o)(4) to note that the regulatory section is now applicable 
only to the transient cycle specified in appendix A of 40 CFR part 
1037. We are also finalizing a new 40 CFR 1037.550(o)(6) to require 
calculating the average powertrain output speed and the average 
powertrain output torque for the cruise cycles. The changes to the 
calculations in 40 CFR 1037.550(o)(6) are necessary to address the 
changes in GEM inputs required for cycle-average fuel maps for cruise 
cycles. We are also adding a new vehicle configuration output matrix 
for cruise cycles to denote the differences that now exist for the 
testing outputs needed for GEM for transient and cruise cycles. As 
discussed in Section III of the preamble, we are changing the 
regression model used for interpolating the cycle-average fuel maps for 
the cruise cycles to improve the accuracy and representativeness of the 
regression model.

V. Statutory Authority and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose any new information collection burden 
under the PRA. OMB has previously approved the information collection 
activities contained in the existing regulations and has assigned OMB 
control numbers 2060-0287. This rule clarifies procedures without 
affecting information collection requirements.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, the impact of concern is any significant 
adverse economic impact on small entities and that the agency is 
certifying that this rule will not have a significant economic impact 
on a substantial number of small entities if the rule has no net burden 
on the small entities subject to the rule. This action is designed to 
make various corrections and adjustments to compliance provisions; as a 
result, we anticipate no costs associated with this rule. We have 
therefore concluded that this action will have no net regulatory burden 
for all directly regulated small entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action imposes no enforceable duty on any 
Tribal, state, or local governments. Requirements for the private 
sector do not exceed $100 million in any one year.

[[Page 45262]]

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have Tribal implications as specified in 
Executive Order 13175. This rule will be implemented at the Federal 
level and affects engine and vehicle manufacturers. Thus, Executive 
Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. There are no environmental health or safety risks created by 
this action that could present a disproportionate risk to children.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution or use of energy. Further, we have concluded that this 
action is not likely to have any adverse energy effects because the 
regulatory changes are limited to certification procedures for meeting 
the Phase 2 GHG standards.

I. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies. NTTAA directs agencies to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards. This action 
involves technical standards.
    With one exception, the standards included in the regulatory text 
as incorporated by reference in 40 CFR part 1037 were all previously 
approved for incorporation by reference (IBR) and no change is included 
in this action. In accordance with the requirements of 1 CFR 51.5, we 
are incorporating by reference new versions of the GEM. EPA is 
publishing new versions of the GEM, which we use for certifying heavy-
duty highway vehicles to the Phase 2 greenhouse gas emission standards 
in 40 CFR part 1037. We are also restoring a version of GEM that we 
withdrew in a different rulemaking. The model calculates GHG emission 
rates for heavy-duty highway vehicles based on input values defined by 
the manufacturer. GEM Version 4.0 applies broadly for Phase 2 vehicles. 
GEM Version 3.0 and GEM Version 3.5.1 apply optionally for model years 
2021 through 2023 to facilitate compliance during a transition period. 
The different versions of GEM are referenced in Sec.  1037.520. The 
model is available from EPA as noted in the amended regulations at 40 
CFR 1037.810.\15\
---------------------------------------------------------------------------

    \15\ GEM is most easily available at www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty.
---------------------------------------------------------------------------

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes this action does not have disproportionately high 
and adverse human health or environmental effects on minority 
populations, low-income populations or indigenous peoples, as specified 
in Executive Order 12898 (59 FR 7629, February 16, 1994). Due to the 
small environmental impact, this regulatory action will not have a 
disproportionate adverse effect on minority populations, low-income 
populations, or indigenous peoples.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

L. Judicial Review

    Under CAA section 307(b)(1), judicial review of this final rule is 
available only by filing a petition for review in the U.S. Court of 
Appeals for the District of Columbia Circuit by September 26, 2022. 
Under CAA section 307(d)(7)(B), only an objection to this final rule 
that was raised with reasonable specificity during the period for 
public comment can be raised during judicial review. CAA section 
307(d)(7)(B) also provides a mechanism for EPA to convene a proceeding 
for reconsideration, ``[i]f the person raising an objection can 
demonstrate to EPA that it was impracticable to raise such objection 
within [the period for public comment] or if the grounds for such 
objection arose after the period for public comment (but within the 
time specified for judicial review) and if such objection is of central 
relevance to the outcome of the rule.'' Any person seeking to make such 
a demonstration should submit a Petition for Reconsideration to the 
Office of the Administrator, Environmental Protection Agency, Room 
3000, William Jefferson Clinton Building, 1200 Pennsylvania Ave. NW, 
Washington, DC 20460, with an electronic copy to the person listed in 
FOR FURTHER INFORMATION CONTACT, and the Associate General Counsel for 
the Air and Radiation Law Office, Office of General Counsel (Mail Code 
2344A), Environmental Protection Agency, 1200 Pennsylvania Ave. NW, 
Washington, DC 20004. Note that under CAA section 307(b)(2), the 
requirements established by this final rule may not be challenged 
separately in any civil or criminal proceedings brought by EPA to 
enforce these requirements.

List of Subjects

40 CFR Part 1036

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Confidential business information, Greenhouse 
gases, Labeling, Motor vehicle pollution, Reporting and recordkeeping 
requirements, Warranties.

40 CFR Part 1037

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Confidential business information, Incorporation 
by reference, Labeling, Motor vehicle pollution, Reporting and 
recordkeeping requirements, Warranties.

Michael S. Regan,
Administrator.

    For the reasons set out in the preamble, we are amending title 40, 
chapter I of the Code of Federal Regulations as set forth below.

[[Page 45263]]

PART 1036--CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY 
HIGHWAY ENGINES

0
1. The authority citation for part 1036 continues to read as follows:

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

0
2. Amend Sec.  1036.150 by adding paragraph (r) to read as follows:

Sec.  1036.150   Interim provisions.

* * * * *
    (r) Fuel maps for the transition to updated GEM. (1) You may use 
fuel maps from model year 2023 and earlier engines for certifying model 
year 2024 and later engines using carryover provisions in Sec.  
1036.235(d).
    (2) Compliance testing will be based on the GEM version you used to 
generate fuel maps for certification. For example, if you perform a 
selective enforcement audit with respect to fuel maps, use the same GEM 
version that you used to generate fuel maps for certification. 
Similarly, we will use the same GEM version that you used to generate 
fuel maps for certification if we perform confirmatory testing with one 
of your engine families.

0
3. Amend Sec.  1036.503 by revising paragraphs (b)(3) and (4) to read 
as follows:

Sec.  1036.503   Engine data and information for vehicle certification.

* * * * *
    (b) * * *
    (3) Additional parameters. Determine fuel consumption at idle as 
described in Sec.  1036.535(c) and (d) and determine cycle-average 
engine fuel maps as described in 40 CFR 1037.550, including cycle-
average engine fuel maps for highway cruise cycles. Set up the test to 
apply accessory load for all operation by primary intended service 
class as described in the following table:

     Table 1 to Paragraph (b)(3) of Sec.   1036.503--Accessory Load
------------------------------------------------------------------------
                                                               Power
                                                           representing
             Primary intended service class               accessory load
                                                               (kW)
------------------------------------------------------------------------
Light HDV...............................................             1.5
Medium HDV..............................................             2.5
Heavy HDV...............................................             3.5
------------------------------------------------------------------------

    (4) Powertrain. Generate powertrain fuel maps as described in 40 
CFR 1037.550 instead of fuel mapping under Sec.  1036.535 or Sec.  
1036.540. Note that the option in 40 CFR 1037.550(b)(2) is allowed only 
for hybrid engine testing. Disable automatic stop-start systems and 
automatic engine shutdown systems when conducting powertrain fuel map 
testing using 40 CFR 1037.550.
* * * * *

Sec.  1036.535   [Amended]

0
4. Amend Sec.  1036.535 by removing and reserving paragraph (d)(2).

0
5. Amend Sec.  1036.540 by revising paragraph (e) to read as follows:

Sec.  1036.540   Determining cycle-average engine fuel maps.

* * * * *
    (e) Determine GEM inputs. Use the results of engine testing in 
paragraph (d) of this section to determine the GEM inputs for the 
transient duty cycle and optionally for each of the highway cruise 
cycles corresponding to each simulated vehicle configuration as 
follows:
    (1) Your declared fuel mass consumption, mfuel[cycle]. 
Using the calculated fuel mass consumption values described in 
paragraph (d) of this section, declare values using the method 
described in Sec.  1036.535(g).
    (2) We will determine mfuel[cycle] values using the 
method described in Sec.  1036.535(h).
    (3) For the transient cycle, calculate engine output speed per unit 
vehicle speed,
[GRAPHIC] [TIFF OMITTED] TR28JY22.015

by taking the average engine speed measured during the engine test 
while the vehicle is moving and dividing it by the average vehicle 
speed provided by GEM. Note that the engine cycle created by GEM has a 
flag to indicate when the vehicle is moving.
    (4) The engine idle speed and torque, by taking the average engine 
speed and torque measured during the engine test while the vehicle is 
not moving. Note that the engine cycle created by GEM has a flag to 
indicate when the vehicle is moving.
    (5) For the cruise cycles, calculate the average engine output 
speed, fnengine, and the average engine output torque 
(positive torque only), Tnengine, while the vehicle is 
moving. Note that the engine cycle created by GEM has a flag to 
indicate when the vehicle is moving.
    (6) Positive work determined according to 40 CFR part 1065, 
W[cycle], by using the engine speed and engine torque 
measured during the engine test while the vehicle is moving. Note that 
the engine cycle created by GEM has a flag to indicate when the vehicle 
is moving.
    (7) The following tables illustrate the GEM data inputs 
corresponding to the different vehicle configurations for a given duty 
cycle:
    (i) For the transient cycle:
    [GRAPHIC] [TIFF OMITTED] TR28JY22.016
    

[[Page 45264]]

    (ii) For the cruise cycles:

             Table 7 to Paragraph (e)(7)(ii) of Sec.   1036.540--Generic Example of an Output Matrix for Cruise Cycle Vehicle Configurations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Configuration
                      Parameter                       --------------------------------------------------------------------------------------------------
                                                           1          2          3          4          5          6          7          8          9
--------------------------------------------------------------------------------------------------------------------------------------------------------
mfuel[cycle].........................................
fnengine[cycle]......................................
Tengine[cycle].......................................
W[cycle].............................................
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

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

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

0
7. Amend Sec.  1037.150 by adding paragraph (bb) to read as follows:

Sec.  1037.150   Interim provisions.

* * * * *
    (bb) Transition to updated GEM. (1) Vehicle manufacturers may 
demonstrate compliance with Phase 2 GHG standards in model years 2021 
through 2023 using GEM Phase 2, Version 3.0, Version 3.5.1, or Version 
4.0 (incorporated by reference in 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 
(incorporated by reference in 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 (incorporated by reference in 
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).

0
8. Amend Sec.  1037.510 by revising paragraph (b) to read as follows:

Sec.  1037.510   Duty-cycle exhaust testing.

* * * * *
    (b) Calculate the official emission result from the following 
equation:
[GRAPHIC] [TIFF OMITTED] TR28JY22.017

Where:

eCO2comp = total composite mass of CO2 
emissions in g/ton-mile, rounded to the nearest whole number for 
vocational vehicles and to the first decimal place for tractors.
PL = the standard payload, in tons, as specified in Sec.  1037.705.
vmoving = mean composite weighted driven vehicle speed, 
excluding idle operation, as shown in table 1 to this section for 
Phase 2 vocational vehicles. For other vehicles, let 
vmoving = 1.
w[cycle] = weighting factor for the appropriate test 
cycle, as shown in table 1 to this section.
m[cycle] = CO2 mass emissions over each test 
cycle (other than idle).
D[cycle] = the total driving distance for the indicated 
duty cycle. Use 2.842 miles for the transient cycle, and use 13.429 
miles for both of the highway cruise cycles.
m[cycle]-idle = CO2 emission rate at idle.

Example:

    Class 7 vocational vehicle meeting the Phase 2 standards based 
on the Regional duty cycle.

PL = 5.6 tons
vmoving = 38.41 mi/hr
wtransient = 20% = 0.20
wdrive-idle = 0% = 0
wparked-idle = 25% = 0.25
w55 = 24% = 0.24
w65 = 56% = 0.56
mtransient = 4083 g
m55 = 13834 g
m65 = 17018 g
Dtransient = 2.8449 miles
D55 = 13.429 miles
D65 = 13.429 miles
mdrive-idle = 4188 g/hr
mparked-idle = 3709 g/hr

[[Page 45265]]

[GRAPHIC] [TIFF OMITTED] TR28JY22.018

* * * * *

0
9. Amend Sec.  1037.520 by revising the introductory text and paragraph 
(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) (incorporated by reference in Sec.  1037.810) 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 standards. Use good 
engineering judgment when demonstrating compliance using GEM. See Sec.  
1037.515 for calculation procedures for demonstrating compliance with 
trailer standards.
* * * * *
    (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, 
unless good engineering judgment indicates that a lower percentage 
should apply.
* * * * *

0
10. Amend Sec.  1037.550 by:
0
a. Revising paragraph (a)(3) introductory text.
0
b. Adding and reserving paragraph (a)(7).
0
c. Adding paragraph (a)(8).
0
d. Revising paragraphs (f) introductory text and (o).
    The additions and revisions read as follows:

Sec.  1037.550   Powertrain testing.

* * * * *
    (a) * * *
    (3) Powertrain testing depends on models to calculate certain 
parameters. You can use the detailed equations in this section to 
create your own models, or use the GEM HIL model contained within GEM 
Phase 2, Version 4.0 (incorporated by reference in Sec.  1037.810) to 
simulate vehicle hardware elements as follows:
* * * * *
    (7) [Reserved]
    (8) Do not apply accessory loads when conducting a powertrain test 
to generate inputs to GEM if torque is measured at the axle input shaft 
or wheel hubs.
* * * * *
    (f) Driveline and vehicle model. Use the GEM HIL model's driveline 
and vehicle submodels or the equations in this paragraph (f) to 
calculate the dynamometer speed setpoint, [fnof]nref,dyno, 
based on the torque measurement location. For all powertrains, 
configure GEM with the accessory load set to zero. For hybrid engines, 
configure GEM with the applicable accessory load as specified in 40 CFR 
1036.503. For all powertrains and hybrid engines, configure GEM with 
the tire slip model disabled.
* * * * *
    (o) Create GEM inputs. Use the results of powertrain testing to 
determine GEM inputs for the different simulated vehicle configurations 
as follows:
    (1) Correct the measured or calculated fuel masses, 
mfuel[cycle], and mean idle fuel mass flow rates, 
mfuelidle, if applicable, for each test result to a mass-
specific net energy content of a reference fuel as described in 40 CFR 
1036.535(f), replacing mfuel with mfuel[cycle] 
where applicable in Eq. 1036.535-4.
    (2) Declare fuel masses, mfuel[cycle], in g/cycle. In 
addition, declare mean fuel mass flow rate for each applicable idle 
duty cycle,mifuelidle. These declared values may not be 
lower than any corresponding measured values determined in this 
section. If you use multiple measurement methods as allowed in 40 CFR 
1036.540(d), follow 40 CFR 1036.535(g) regarding the use of direct and 
indirect fuel measurements and the carbon balance error verification. 
These declared values, which serve as emission standards, collectively 
represent the powertrain fuel map for certification.
    (3) [Reserved]
    (4) For the transient cycle specified in Sec.  1037.510(a)(2)(i), 
calculate powertrain output speed per unit of vehicle speed,
[GRAPHIC] [TIFF OMITTED] TR28JY22.019

using one of the following methods:

    (i) For testing with torque measurement at the axle input shaft:
    [GRAPHIC] [TIFF OMITTED] TR28JY22.020
    
Example:

ka = 4.0
rB = 0.399 m
[GRAPHIC] [TIFF OMITTED] TR28JY22.021

[[Page 45266]]

    (ii) For testing with torque measurement at the wheel hubs, use Eq. 
1037.550-8 setting ka equal to 1.
    (iii) For testing with torque measurement at the engine's 
crankshaft:
[GRAPHIC] [TIFF OMITTED] TR28JY22.022

Where:

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

Example:

fnengine = 1870 r/min = 31.17 r/s
vref = 19.06 m/s
[GRAPHIC] [TIFF OMITTED] TR28JY22.023

    (5) Calculate engine idle speed, by taking the average engine speed 
measured during the transient cycle test while the vehicle speed is 
below 0.100 m/s. (Note: Use all the charge-sustaining test intervals 
when determining engine idle speed for plug-in hybrid engines and 
powertrains.)
    (6) For the cruise cycles specified in Sec.  1037.510(a)(2)(ii), 
calculate the average powertrain output speed, fnpowertrain, 
and the average powertrain output torque (positive torque only), 
Tpowertrain, at vehicle speed at or above 0.100 m/s. (Note: 
Use all the charge-sustaining and charge-depleting test intervals when 
determining fnpowertrain and Tpowertrain for 
plug-in hybrid engines and powertrains.)
    (7) Calculate positive work, W[cycle], as the work over 
the duty cycle at the axle input shaft, wheel hubs, or the engine's 
crankshaft, as applicable, when vehicle speed is at or above 0.100 m/s.
    (8) The following tables illustrate the GEM data inputs 
corresponding to the different vehicle configurations for a given duty 
cycle:
    (i) For the transient cycle:
    [GRAPHIC] [TIFF OMITTED] TR28JY22.024
    
    (ii) For the cruise cycles:

              Table 3 to Paragraph (o)(8)(ii) of Sec.   1037.550--Generic Example of Output Matrix for Cruise Cycle Vehicle Configurations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Configuration
                      Parameter                       --------------------------------------------------------------------------------------------------
                                                           1          2          3          4          5          6          7          8          9
--------------------------------------------------------------------------------------------------------------------------------------------------------
mfuel[cycle].........................................
fnpowertrain[cycle]..................................
Tpowertrain[cycle]...................................
W[cycle].............................................
--------------------------------------------------------------------------------------------------------------------------------------------------------

0
11. Amend Sec.  1037.810 by revising paragraph (c) to read as follows:

Sec.  1037.810   Incorporation by reference.

* * * * *
    (c) U.S. EPA, Office of Air and Radiation, 2565 Plymouth Road, Ann 
Arbor, MI 48105, www.epa.gov.
    (1) Greenhouse gas Emissions Model (GEM), Version 2.0.1, September 
2012 (``GEM version 2.0.1''), IBR approved for Sec.  1037.520.
    (2) Greenhouse gas Emissions Model (GEM) Phase 2, Version 3.0, July 
2016 (``GEM Phase 2, Version 3.0''); IBR approved for Sec.  
1037.150(bb).
    (3) Greenhouse gas Emissions Model (GEM) Phase 2, Version 3.5.1, 
November

[[Page 45267]]

2020 (``GEM Phase 2, Version 3.5.1''); IBR approved for Sec.  
1037.150(bb).
    (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(bb); 1037.520; 1037.550(a).
    (5) GEM's MATLAB/Simulink Hardware-in-Loop model, Version 3.8, 
December 2020 (``GEM HIL model 3.8''); IBR approved for Sec.  
1037.150(bb).

    Note 1 to paragraph (c): The computer code for these models is 
available as noted in paragraph (a) of this section. A working 
version of the software is also available for download at 
www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty.

* * * * *
[FR Doc. 2022-16031 Filed 7-27-22; 8:45 am]
BILLING CODE 6560-50-P