Rule2021-05306
Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and Other Technical Amendments
Primary source
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Published
June 29, 2021
Effective
July 29, 2021
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is amending the test procedures for heavy-duty engines and vehicles to improve accuracy and reduce testing burden. EPA is also making other regulatory amendments concerning light-duty vehicles, heavy-duty vehicles, highway motorcycles, locomotives, marine engines, other nonroad engines and vehicles, and stationary engines. These amendments affect the certification procedures for exhaust emission standards and related requirements. EPA is finalizing similar amendments for evaporative emission standards for nonroad equipment and portable fuel containers. The amendments increase compliance flexibility, harmonize with other requirements, add clarity, correct errors, and streamline the regulations. Given the nature of the amendments, they will have neither significant environmental impacts nor significant economic impacts for any sector.
Full Text
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<title>Federal Register, Volume 86 Issue 122 (Tuesday, June 29, 2021)</title>
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[Federal Register Volume 86, Number 122 (Tuesday, June 29, 2021)]
[Rules and Regulations]
[Pages 34308-34590]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-05306]
[[Page 34307]]
Vol. 86
Tuesday,
No. 122
June 29, 2021
Part II
Environmental Protection Agency
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40 CFR Parts 9, 59, 60, et al.
Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and
Other Technical Amendments; Final Rule
Federal Register / Vol. 86, No. 122 / Tuesday, June 29, 2021 / Rules
and Regulations
[[Page 34308]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 59, 60, 85, 86, 88, 89, 90, 91, 92, 94, 1027, 1033,
1036, 1037, 1039, 1042, 1043, 1045, 1048, 1051, 1054, 1060, 1065,
1066, 1068, and 1074
[EPA-HQ-OAR-2019-0307; FRL-10018-52-OAR]
RIN 2060-AU62
Improvements for Heavy-Duty Engine and Vehicle Test Procedures,
and Other Technical Amendments
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is amending the test
procedures for heavy-duty engines and vehicles to improve accuracy and
reduce testing burden. EPA is also making other regulatory amendments
concerning light-duty vehicles, heavy-duty vehicles, highway
motorcycles, locomotives, marine engines, other nonroad engines and
vehicles, and stationary engines. These amendments affect the
certification procedures for exhaust emission standards and related
requirements. EPA is finalizing similar amendments for evaporative
emission standards for nonroad equipment and portable fuel containers.
The amendments increase compliance flexibility, harmonize with other
requirements, add clarity, correct errors, and streamline the
regulations. Given the nature of the amendments, they will have neither
significant environmental impacts nor significant economic impacts for
any sector.
DATES: This final rule is effective on July 29, 2021. The incorporation
by reference of certain publications listed in this regulation is
approved by the Director of the Federal Register as of July 29, 2021.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2019-0307. All documents in the docket are
listed on the <a href="http://www.regulations.gov">www.regulations.gov</a> website. Although listed in the
index, some information is not publicly available, e.g., confidential
business information (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. Publicly available docket materials are
available either electronically in <a href="http://www.regulations.gov">www.regulations.gov</a> 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. Note that the EPA Docket Center and Reading Room were
closed to public visitors on March 31, 2020, to reduce the risk of
transmitting COVID-19. The Docket Center staff will continue to provide
remote customer service via email, phone, and webform. The telephone
number for the Public Reading Room is (202) 566-1744, and the telephone
number for the Air Docket is (202) 566-1742. For further information on
EPA Docket Center services and the current status, go to <a href="https://www.epa.gov/dockets">https://www.epa.gov/dockets</a>.
FOR FURTHER INFORMATION CONTACT: Alan Stout, Office of Transportation
and Air Quality, Assessment and Standards Division, Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
telephone number: (734) 214-4805; email address: <a href="/cdn-cgi/l/email-protection#aad9dec5dfde84cbc6cbc4eacfdacb84cdc5dc"><span class="__cf_email__" data-cfemail="cdbeb9a2b8b9e3aca1aca38da8bdace3aaa2bb">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. General Information
II. Heavy-Duty Highway Amendments
A. Test Procedures and Compliance Model Changes
B. Heavy-Duty Engine GHG Emission Standards and Flexibility
C. Heavy-Duty Vehicle GHG Emission Standards and Flexibility
D. Onboard Diagnostics (``OBD'')
III. Other Amendments
A. Ethanol-Blend Test Fuels for Nonroad Spark-Ignition Engines
and Vehicles, Highway Motorcycles, and Portable Fuel Containers
B. Removing Obsolete CFR Content
C. Certification Fees (40 CFR Part 1027)
D. Additional Amendments for Motor Vehicles and Motor Vehicle
Engines (40 CFR Parts 85 and 86)
E. Additional Amendments for Locomotives (40 CFR Part 1033)
F. Additional Amendments for Land-Based Nonroad Diesel Engines
(40 CFR Part 1039)
G. Additional Amendments for Marine Diesel Engines (40 CFR Parts
1042 and 1043)
H. Portable Fuel Containers (40 CFR Part 59)
I. Evaporative Emission Standards for Nonroad Spark-Ignition
Engines and Equipment (40 CFR Part 1060)
J. Additional Amendments for Nonroad Spark-Ignition Engines at
or Below 19 kW (40 CFR Part 1054)
K. Amendments for General Compliance Provisions (40 CFR Part
1068)
L. Other Requests for Comment
IV. Statutory Authority and Executive Order Reviews
I. General Information
Does this action apply to me?
This action relates to companies that manufacture, sell, or import
into the United States new heavy-duty engines or Class 2b through 8
trucks, including combination tractors, vocational vehicles, and all
types of buses.\1\ Vocational vehicles include municipal, commercial,
and recreational vehicles. Additional amendments apply for different
manufacturers of light-duty vehicles, light-duty trucks, highway
motorcycles, stationary engines, and various types of nonroad engines,
vehicles, and equipment.\2\ 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.
\2\ ``Light-duty vehicle'' and ``light-duty truck'' are defined
in 40 CFR 86.1803-01.
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Examples of
potentially
NAICS codes a NAICS titles regulated
entities
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333618, 336111, 336112, 336120, Other Engine Motor vehicle
336211, 336212, 336611, 336999. Equipment manufacturers and
Manufacturing, engine
Automobile manufacturers.
Manufacturing,
Light Truck and
Utility Vehicle
Manufacturing,
Heavy Duty Truck
Manufacturing,
Motor Vehicle
Body
Manufacturing,
Truck Trailer
Manufacturing,
Ship Building and
Repairing, All
Other
Transportation
Equipment
Manufacturing.
811111, 811112, 811198, 423110.. General Automotive Commercial
Repair, importers of
Automotive vehicles and
Exhaust System vehicle
Repair, All Other components.
Automotive Repair
and Maintenance,
Automobile and
Other Motor
Vehicle Merchant
Wholesalers.
335312, 811198.................. Motor and Alternative fuel
Generator vehicle
Manufacturing, converters.
All Other
Automotive Repair
and Maintenance.
[[Page 34309]]
326199, 332431.................. All Other Plastics Portable fuel
Product container
Manufacturing, manufacturers.
Metal Can
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 regulations that implement our air pollutant
emission standards for engines, vehicles and mobile equipment. The
amendments include corrections, clarifications, and flexibilities for
multiple types of vehicles, engines and equipment.
The majority of these amendments modify existing test procedures
for heavy-duty highway engines and vehicles. These test procedure
changes improve accuracy, and in some cases, reduce test burden. They
mainly apply for measurement of greenhouse gas (GHG) pollutants
(primarily CO2), though some apply for criteria pollutants (such as
NO<INF>X</INF>), as well. See Section II.A.
Additional heavy-duty highway amendments update EPA regulations to
enhance implementation of existing emission standards. For example,
some changes reduce the likelihood that manufacturers would need to
duplicate certification efforts to comply with EPA, Canadian, and
Californian standards. Some amendments make it easier for manufacturers
to more fully account for the emission benefits of advanced emission
control technology, which could provide them the opportunity to
generate additional emission credits. These heavy-duty highway
amendments are described in Section II.B.
This rule includes other amendments that are generally
administrative or technical in nature and include amendments for
nonroad engines and vehicles, stationary engines, and portable fuel
containers. These amendments are described in Section III. Perhaps the
most visible administrative amendment is the elimination of hundreds of
pages of obsolete regulations, which is described in Section III.B.
EPA published a proposed rule on May 12, 2020 (85 FR 28140). This
final rule follows from that proposal, with several adjustments that
reflect EPA's consideration of comments received. Most of the proposed
revisions from that document are addressed in this final rule. EPA is
also issuing a new notice of proposed rulemaking to supplement the
earlier proposed rule, published in the Proposed Rules section of this
issue of the Federal Register, titled ``Improvements for Heavy-Duty
Engine and Vehicle Test Procedures,'' docket number EPA-HQ-OAR-2019-
0307; FRL-10018-51-OAR. In the supplemental proposal, EPA proposes
further amendments concerning only certain specific aspects of the
Greenhouse gas Emissions Model (GEM) (see Section II of the preamble to
the supplemental proposal).
The proposed rule included requests for comment on a wide range of
issues, including some broad areas where we were interested only in
gathering information for potential future rulemaking(s). This preamble
does not include a discussion of those comment areas where we are not
taking any action in this final rule. The ``Improvements for Heavy-Duty
Engine and Vehicle Test Procedures, and other Technical Amendments
Response to Comments'' document (``Response to Comments'') in the
docket for this rulemaking includes a summary of the input received
from commenters and EPA's responses.\3\
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\3\ EPA, ``Improvements for Heavy-Duty Engine and Vehicle Test
Procedures, and other Technical Amendments Response to Comments,''
December 2020, Docket EPA-HQ-OAR-2019-0307, Publication Number: EPA-
420-R-20-026.
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In addition, we have prepared a docket memo with redline text to
highlight all the changes to the regulations in the proposed rule.\4\
This is especially helpful for reviewing provisions that we are
removing from the Code of Federal Regulations. For obsolete provisions
we are removing, see especially 40 CFR 1027.105, 1033.150, 1042.145,
1045.145, 1048.145, 1051.145, 1054.145, and 1054.625. We prepared
additional docket memos to show regulatory changes after the proposed
rule.\5\
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\4\ ``Redline Document Showing Proposed Changes to Regulatory
Text in the Heavy-Duty Greenhouse Gas Amendments'', EPA memorandum
from Alan Stout to Docket EPA-HQ-OAR-2019-0307, March 2020.
\5\ ``Redline Version of EPA's Final Regulatory Amendments for
Heavy-Duty Greenhouse Gas Standards and other Programs'', EPA
memorandum from Alan Stout to Docket EPA-HQ-OAR-2019-0307, December
9, 2020.
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What are the incremental costs and benefits of this action?
This action is limited in scope and does not include amendments
that have significant economic or environmental impacts. EPA has
therefore not estimated the potential costs or benefits of this final
rule (and we did not for the proposal).
II. Heavy-Duty Highway Amendments
A. Test Procedures and Compliance Model Changes
Since the promulgation of the Phase 2 regulations, manufacturers
have been revising their internal test procedures to ensure they will
be able to comply with the new requirements that begin in model year
2021. In doing so, they have identified several areas in which the test
procedure regulations could be improved (in terms of overall accuracy,
repeatability and clarity) without changing the effective stringency of
the standards.
EPA is making numerous changes to the test procedure regulations to
address manufacturers' concerns and other issues we have identified.
These changes are described below. The list includes numerous editorial
changes that simply correct typographical/formatting errors or revise
the text to improve clarity. Although these amendments are being made
primarily in the context of heavy-duty engines and vehicles, the
amendments to part 1065 will also apply to nonroad engines, and the
amendments to part 1066 will also apply to light-duty vehicles. Since
these amendments are mostly editorial or adding flexibility, they will
not adversely impact these other sectors.
1. 40 CFR Part 1036 Test Procedures
EPA proposed several updates to the testing and measurement
provisions of part 1036, subpart F, and appendices of part 1036 related
to how to measure emissions from heavy-duty engines and requested
comment on general improvements to the engine test procedures and
compliance provisions (85 FR 28141). This section presents the changes
we are adopting to engine test procedures after consideration of
comments received. Additional details on some of these and other engine
testing and measurement amendments or clarifications requested by
[[Page 34310]]
commenters and our responses are available in Chapter 2 of our Response
to Comments. Amendments to other subparts of part 1036 (i.e.,
amendments not directly related to test procedures) are discussed in
Section II.B.
These updates are primarily for the purposes of adding flexibility
and reducing variability in test results. Additional information that
led to and supports these changes arose from a test program at
Southwest Research Institute (SwRI) that was jointly funded by EPA and
the Truck and Engine Manufacturers Association (EMA).\6\
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\6\ Sharp, Christopher A., et al., ``Measurement Variability
Assessment of the GHG Phase 2 Fuel Mapping Procedure'', Final
Report, Southwest Research Institute, December 2019.
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We are generally finalizing revisions as proposed; however, some
revisions include further changes and clarifications after
consideration of public comments to better ensure clarity, accuracy and
consistency with the intent of the proposed rule.
<bullet> Section 1036.501(g)--Providing a new paragraph (g) to
specify duty cycles for testing model year (MY) 2016-2020 engines,
including additional clarifications to the proposed amendment to refer
to the steady-state duty cycle as the Supplemental Emission Test
(``SET'') rather than the Ramped Modal Cycle (``RMC'') to avoid
confusion as steady-state cycles are run as RMCs in many standard
setting parts, and to change a reference for the Federal Test Procedure
(``FTP'') duty cycle from appendix B of 40 CFR part 1036 to 40 CFR
1036.510 because 40 CFR 1036.510 gives an overview of the duty cycle
and provides the reference to appendix B of 40 CFR part 1036.
<bullet> Section 1036.501(h)--Renumbering existing paragraph (g)
concerning testing of MY 2021 and later engines as new paragraph (h),
modifying paragraph (h)(1) to address restarting the engine during
dynamometer testing for engines with stop-start technologies, and
adding paragraph (h)(3) (shown as (h)(2) in the proposed rule) to
cross-reference transient test cycle specifications, including
additional clarifications in final paragraph (h)(2) to refer to the
Supplemental Emission Test cycle to avoid confusion as steady-state
cycles are run as RMCs in many standard setting parts and in paragraph
(h)(2)(ii) that weighting factors for the Supplemental Emission Test
are to be applied to CO2 to calculate the composite emission result.
<bullet> Section 1036.503--Migrating Sec. 1036.510 to new Sec.
1036.503, renumbering existing paragraph (d) as new paragraph (c),
updating paragraphs (b) and (c)(1) through (3) and adding paragraphs
(c)(4) and (5) and (d), including provisions to specify that the engine
manufacturer must provide idle speed and torque to the vehicle
manufacturer and to provide additional direction on handling data
points for a low speed governor where the governor is active. We
further modified proposed paragraph (b) to denote that there are four
methods to generate fuel maps with the addition of the hybrid
powertrain and hybrid engine testing procedures and to more clearly
explain which method(s) apply to which application, paragraphs (b)(1)
and (2) to add more specificity to which referenced paragraphs in Sec.
1036.535 are applicable, paragraph (b)(3) to clarify that the option in
Sec. 1037.520(d)(2) is only allowed for hybrid powertrain testing and
not powertrain testing in general, and added paragraph (b)(4) to
include a method to perform hybrid engine testing. We also further
updated paragraph (c)(1) to clarify how to measure torque curve for
engines that have a rechargeable energy storage system (RESS) and for
those that don't.
<bullet> Section 1036.505--Adding paragraph (b) to give direction
on both engine and powertrain testing and modifying Table 1 to include
vehicle speed and grade parameters to facilitate the hybrid powertrain
testing option. We further modified the proposed language in this
section by: Adding a new paragraph (b)(2)(v) to calculate curb mass for
hybrid powertrain testing as this calculation is needed to determine
the linear equivalent mass of rotational moment of inertias in
clarified paragraph (b)(2)(vi), adding reference speed determination
requirements for powertrain testing in paragraphs (c)(2)(i) and (ii) to
address underspeed conditions in the hybrid powertrain SET testing,
including a removal of default A, B, and C SET speeds and calculation
of the A and B speeds based on C speed, modifying Table 1 further to
include vehicle speed and grade parameters to facilitate the hybrid
powertrain testing option so the road grade equation is now vehicle
speed-dependent to address vehicle underspeed concerns corresponding to
the determination and use of vehicle C speed, and replacing ramped
modal cycle with supplemental emission test for the reason discussed in
the first bullet of this subsection of the preamble.
<bullet> Section 1036.510--Providing a new section regarding
transient testing of engines and hybrids to facilitate hybrid
certification for both GHG and criteria pollutants.
<bullet> Section 1036.525(a)--Adding a clarification in the final
rule that the hybrid engine testing procedure in this section applies
only for model year 2014 to 2020 hybrid engines since the new hybrid
powertrain and hybrid engine test procedure being adopted in this
rulemaking will apply for model year 2021 and later engines.
<bullet> Section 1036.525(d)(4)(i)--Editorial revisions to equation
and the addition of example calculations.
<bullet> Section 1036.527--Adding a section to provide a means to
determine powertrain systems rated power and continuous rated power, to
facilitate the hybrid and conventional powertrain testing options. This
test procedure is applicable for powertrain testing defined in 40 CFR
1037.550 for both the engine and vehicle standards. We further modified
the proposed language, including modifying how the test is carried out
by reducing the number of test intervals from 9 to 1, paragraph (e) to
address the determination of Psys for speed and torque measurements at
different locations, with new paragraphs (g) and (h) to provide an
improved method for determining continuous rated power and vehicle C
speed, and addressed typographical errors.
<bullet> Section 1036.530(a), (b)(1)(i) and (ii), and (b)(2)(i) and
(ii)--Updating carbon mass fraction determination to allow analysis by
a single lab only to facilitate on-line analysis from pipeline supplied
natural gas and adding the ASTM International method for determination
of test fuel mass-specific energy content for natural gas. We have
further modified the proposed language by clarifying in paragraph (a)
that the infrequent regeneration adjustment factors (IRAF) are applied
to CO2 emission results for all duty-cycles, not just cycle average
engine fuel map results, and updating paragraph (b) to require test
fuel mass-specific energy content and carbon mass fraction to be
analyzed by at least three different labs and the median of all the
results to be used in the calculation. We are also adding a
recommendation that you screen your results to determine if additional
observations are needed by performing an outlier test and provided
critical values for this check. The critical values were determined as
1.27 times the method reproducibility R. The R value used for fuel
mass-specific energy content is 0.234 which is the published R value
for ASTM D4809 and the R value used for carbon mass fraction is 1.23,
which was based on analysis of the fuel survey data for ASTM D5291 that
was used in the Fuel Mapping Variability Study at SwRI.
<bullet> Section 1036.530 Table 1--Updating footnote format in
table.
[[Page 34311]]
<bullet> Section 1036.535--Generally updating to improve the engine
fuel mapping test procedures based on the jointly funded EPA-EMA test
program. The overall result of these updates is to reduce the
variability of the emission test results to reduce lab-to-lab
variability. We further modified the proposed language by adding
paragraph (h) to describe how EPA will determine the official fuel
consumption rate during a confirmatory test, based on carbon balance
results, updating paragraph (b)(7)(iv) to require validation of test
intervals that were complete prior to a lab equipment or engine
malfunction, updating the variable description for w<INF>Cmeas</INF> in
paragraph (b)(8) to make clear that you may not account for the
contribution to [alpha], [beta], [gamma], and [delta] of diesel exhaust
fluid or other non-fuel fluids injected into the exhaust, and
clarifying regulatory text and correcting paragraph references.
<bullet> Section 1036.540--Generally updating to improve the cycle-
average engine fuel mapping test procedure as a result of the jointly
funded EPA-EMA test program at SwRI. The overall result of these
updates is to reduce the variability of the emission test results to
reduce lab-to-lab variability. We further modified the proposed
language in a few ways by adding paragraph (b)(4) to address the
ability of gaseous fueled engines with single point fuel injection to
pass alternate cycle statistics to validate the transient duty cycle in
40 CFR part 1037, appendix I, by adding paragraph (e)(2) to describe
how EPA will determine the official fuel consumption rate during a
confirmatory test, based on carbon balance results, by deleting the
requirement for EPA to use an average of indirect measurement of fuel
flow with dilute sampling and direct sampling for fuel mapping as EPA
will now perform the carbon balance verification in 40 CFR 1065.543,
and by generally adding some clarifying text.
<bullet> Section 1036.543--Adding a section to address carbon
balance error verification. This is a result of the jointly funded EPA-
EMA test program. The overall result of these updates is to reduce the
variability of the emission test results to reduce lab-to-lab
measurement variability.
<bullet> Section 1036.801--Adding a definition for hybrid engine to
correspond with the addition of the hybrid powertrain test procedures
to part 1036. Modifying the definition from the proposed language to
provide examples of hybrid engine architecture and hybrid energy
storage systems.
<bullet> Section 1036.801--Adding definitions for ``hybrid
powertrain'' and ``mild hybrid'' in the final rule. These definitions
are needed as a result of adding hybrid powertrain test procedures to
part 1036, subpart F, including mild hybrid certification where engine
testing can use a transmission model. The definitions make clear what
hybrid architectures are covered by each of these terms.
<bullet> Section 1036.801--Updating definition of ``steady-state''
to clarify that fuel map and idle tests are steady-state tests.
<bullet> Section 1036.805(b)--Updating quantity and quantity
descriptions, including some changes to those proposed to ensure
consistency throughout the part.
<bullet> Section 1036.805(c) and (d)--Updating table introductory
sentence and column headings in the table to be consistent with format
in other parts.
<bullet> Section 1036.805(e)--Updating acronyms and abbreviations,
including some changes to those proposed to ensure that the table
contained all that were used throughout the part.
<bullet> Section 1036.805(f)--Adding gravitational constant,
including an updated value for the gravitational constant based on
consideration of comments received on the proposal.
<bullet> Part 1036, appendix A--Adding a new appendix A to provide
a historic summary of previous emission standards which EPA originally
adopted under 40 CFR part 85 or 86, that apply to compression-ignition
engines produced before model year 2007 and to spark-ignition engines
produced before model year 2008.
<bullet> Part 1036, appendix B(a)--Adding a new paragraph (a) of
appendix B to specify transient duty cycles for the engine and
powertrain testing described in Sec. 1036.510.
<bullet> Part 1036, appendix B(b)--Adding a new paragraph (b) of
appendix B to migrate over the spark-ignition FTP duty cycle from part
86, which includes no changes to the FTP duty-cycle weighting factors
or the duty-cycle speed values from the current heavy duty diesel
engine (HDDE) FTP duty cycle that applies to criteria pollutant
regulation in paragraph (f)(1) of 40 CFR part 86, appendix I, a change
to the negative torque values, and migration of the HDDE FTP drive
schedule to paragraph (b) of 40 CFR part 1036, appendix B, to add
vehicle speed and road grade to the duty-cycle to facilitate powertrain
testing for compliance with the HD Phase 2 GHG standards. The change to
negative torque values is the removal of and footnoting of the negative
normalized vehicle torque values over the HDDE FTP duty-cycle. The
footnote denotes that these torque points are controlled using closed
throttle motoring, which would then match how negative torque values
have been controlled in the HDDE FTP. This change also reflects the way
that engine manufacturers are already controlling to negative torque
from spark-ignition engines and harmonizes the methodology with the
HDDE FTP, with no effect on stringency. The spark-ignition engine
denormalization equation in 40 CFR 86.1333(a)(1)(ii) includes division
by 100 which equates it to the denormalization equation in 40 CFR
1065.610(c)(1) (Equation 1065.610-3), with no effect on stringency. We
have further modified the proposed language in this section by updating
the road-grade coefficients to reflect additional refinement of the
road-grade development process that is described in Section II.A.7 of
the preamble.
<bullet> Part 1036, appendix B(c)--Adding a new paragraph (c) of 40
CFR part 1036, appendix B, to migrate over the compression-ignition FTP
duty cycle from part 86, which includes no changes to the HDDE FTP
weighting factors or the duty-cycle torque values from the duty cycle
that currently apply to criteria pollutant regulations in paragraph
(f)(2) of 40 CFR part 86, appendix I, a change to the speed values that
does not influence the ultimate denormalized speed, and migration of
the HDDE FTP drive schedule to add vehicle speed and road grade to the
duty-cycle to facilitate powertrain testing for compliance with the
Phase 2 GHG standards. The change to speed values takes the normalized
vehicle speeds over the HDDE FTP duty-cycle and multiplies them by 100/
112 to eliminate the need to divide by 112 in the diesel engine
denormalization equation in 40 CFR 86.1333(a)(1)(i). This eliminates
the need for use of a denormalization equation and allows commonization
(between compression- and spark-ignition engines) of the use of the
denormalization equation in 40 CFR 1065.610(c)(1) (Equation 1065.610-
3), with no effect on stringency. We have further modified the proposed
language in this section by updating the road grade coefficients to
reflect additional refinement of the road grade development process
that is described in Section II.A.7 of the preamble.
2. 40 CFR Part 1037 Test Procedures
EPA proposed several updates to the testing and measurement
provisions of 1037 subpart F related to how to measure emissions from
heavy-duty vehicles and determine certain GEM inputs and requested
comment on general improvements to the vehicle test procedures and
compliance provisions (see 85 FR 28142). This section presents
[[Page 34312]]
the changes we are adopting to vehicle test procedures after
consideration of comments received. Chapter 2 of our Response to
Comments includes additional details on some of these amendments, as
well as other testing and measurement amendments or clarifications
requested by commenters and our responses. Amendments for other
subparts of part 1037 (i.e., amendments not directly related to test
procedures) are discussed in Section II.C.15. We are generally
finalizing revisions as proposed; however, some revisions include
further changes and clarifications after consideration of public
comments to better ensure clarity, accuracy and consistency with the
intent of the proposed rule.
<bullet> Section 1037.501(i)--Adding paragraph (i) to note that the
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.
<bullet> Section 1037.510(a)(2)--Updating the powertrain testing
procedure used to generate GEM inputs to reduce the variability of the
emission test results and to improve lab-to-lab measurement variability
consistent with the results from the jointly funded EPA-EMA test
program at SwRI.
<bullet> Section 1037.510 Table 1--Updating footnote format in
table.
<bullet> Section 1037.510(d)--Clarifying the reference to
specifically refer to paragraphs ``(b) and (c)'' of Sec. 1066.425.
<bullet> Section 1037.510(e)--Clarifying to specifically state that
the use of cruise control is optional.
<bullet> Section 1037.515 Table 2--Correcting a table entry to
include the proper mathematical symbols in response to a comment by the
California Air Resources Board (CARB).
<bullet> Section 1037.515 Table 3--Updating footnote format in
table.
<bullet> Section 1037.520--Updating a reference to reflect the
updated version of the GEM model released in conjunction with this
rulemaking.
<bullet> Section 1037.520(b)(3)(i)--Adding a reference to Sec.
1037.525 to clarify how to determine a high-roof tractor's aerodynamic
test results in response to a comment request from EMA.
<bullet> Section 1037.520 Table 4--Correcting a typographical error
in a tractor aerodynamic test result C<INF>d</INF>A value for Bin III
low-roof cabs.
<bullet> Section 1037.520 Table 5--Correcting a typographical error
in a tractor input C<INF>d</INF>A value for Bin II High-Roof Sleeper
Cabs.
<bullet> Section 1037.520(c)--Adding a clarification to Sec.
1037.520(c)(6) and updating the GEM user guide to clarify that a time-
and load-weighted average be applied to calculate the rolling
resistance of tires installed on liftable axles, given that tires on
liftable axles are only in contact with the ground when the axle is in
a deployed state in response to a comment from EMA.
<bullet> Section 1037.520 Table 6--Updating footnote format in
table.
<bullet> Section 1037.520 Table 7--Clarifying that the nonwheel-
related weight reductions from alternative materials applied to
tractors for non-suspension crossmembers is for a set of three.
<bullet> Section 1037.520 Table 8--Adding two footnotes to address
how weight reduction values apply and what values to use for medium
heavy-duty vehicles (Medium HDV) with 6x4 or 6x2 axle configurations.
Also see Section II.C.3.
<bullet> Section 1037.520(f)--Updating a cross-reference.
<bullet> Section 1037.520(g)--Adding and clarifying which vehicle
characteristics need to be reported, including providing a better
description in paragraph (g)(2)(iv) of the 6x4D drive axle
configuration as well as qualifying conditions for use of this
configuration. After considering comments received by Allison and Ford,
we are further modifying this paragraph by noting in paragraph (g)(1),
and similarly in Sec. 1037.231(b)(7), that available forward gear
means the vehicle has the hardware and software to allow operation in
those gears and providing in paragraph (g)(2)(i) that the 4x2 drive
axle configuration is available to vehicles with two drive axles where
one of them is disconnectable and designed to be connected only when
used in off road or slippery road conditions and based on a qualifying
condition.
<bullet> Section 1037.520(h)--Adding provisions to determine
appropriate vehicle idle speed based on vehicle service class and
applicable engine standard, including in the final rule a clarification
that the 750 rpm value applies to Light HDV and Medium HDV vocational
vehicles and providing an idle speed value of 700 rpm for Medium HDV
tractors, corresponding to the idle speed used to set the standards for
those vehicles, in response to a comment from EMA. These final
provisions incorporated in a new table format, with an updated footnote
noting the appropriate adjustable idle speed to choose if an engine
cannot operate at the idle speed specified in the table.
<bullet> Section 1037.520(i)--Adding that a manufacturer can
characterize a torque converter, in addition to an axle and
transmission, which will improve the accuracy of GEM by replacing
default GEM values with more representative values.
<bullet> Section 1037.520(j)(2)--Removing a superfluous reference
to tractors in paragraph (j)(2)(i); clarifying paragraph (j)(2)(iii) in
response to a comment from EMA to indicate how to demonstrate the
performance of high-efficiency air conditioning compressors.
<bullet> Section 1037.520(j)(4) Table 9--Including additional
combinations of idle reduction technologies and their corresponding GEM
input values.
<bullet> Section 1037.520(j)(5)--Correcting typographical error
that transposed school and coach bus GEM inputs.
<bullet> Section 1037.525--See Section II.A.6 for a description of
comments and final revisions to this section.
<bullet> Section 1037.528--Replacing the phrase ``primary
procedures'' with ``reference method'' for tractors and ``alternate
procedures'' with ``an alternate method'' for trailers to maintain
consistency with terminology used throughout subpart F.
<bullet> Section 1037.528(c)--Clarifying that the conditions listed
in paragraph (c) apply to each run separately.
<bullet> Section 1037.528(e)--Removing requirement that the
anemometer be ``electro-mechanical'' to rely instead on the
specifications outlined in the existing reference to SAE J1263.
<bullet> Section 1037.528(g)(3)--Clarifying that the measured air
direction correction is ``from all the high-speed segments.''
<bullet> Section 1037.528(h)(3)(i)--Clarifying how to account for
measurement noise near the 2 mile/hour boundary.
<bullet> Section 1037.528(h)(6)--Adding a definition of
DF<INF>TRR</INF> to the introduction of paragraph (h)(6) to clarify the
required calculations; relocating the proposed direction to determine
the difference in rolling resistance between 65 mph and 15 mph for each
tire and to use good engineering judgment when measuring multiple
results to paragraph (v) with the corresponding DF<INF>TRR</INF>
equation.
<bullet> Section 1037.528--Updating equation 11 and the
corresponding example to include the appropriate variable to represent
inflation pressure variable with a lowercase ``p''.
<bullet> Section 1037.528--Updating equation 13 to include
appropriate units for the ambient temperature variable.
<bullet> Section 1037.528--Updating equation 14 to replace a ``+''
with a ``-'' to correct a typographical error.
<bullet> Section 1037.528(h)(12)--Updating a variable name to
provide consistency with updates made to Sec. 1037.525.
[[Page 34313]]
<bullet> Section 1037.532--See Section II.A.6 for a description of
comments and final revisions to this section.
<bullet> Section 1037.534--Updating equation 6 and the
corresponding example to include the appropriate variable to represent
increments by italicizing the ``i''.
<bullet> Section 1037.540--Updating equations 1, 2, and 3 to
include the appropriate variable to represent increments by italicizing
the ``i''.
<bullet> Section 1037.540 Table 1--Updating footnote format in
table; updating a parameter name.
<bullet> Section 1037.540(e) and (f)--Removing incorrect cross-
reference to Sec. 1036.540(d)(5); adding reference to definition of
standard payload.
<bullet> Section 1037.550--Updating the powertrain testing
procedure to reduce the variability of the emission test results and
improve lab-to-lab variability consistent with the results from the
jointly funded EPA-EMA test program at SwRI. We further modified this
section to include an introduction paragraph and reorganized paragraphs
with new paragraph headings to improve navigation. Additional
modifications to this section in the final rule include clarifying in
paragraph (a)(3) options available to create the models for powertrain
testing, adding clarifications in several paragraphs to address where
the torque and speed are measured based on powertrain setup, adding a
new paragraph (f)(2) to address testing of hybrid engines using the
transmission model in GEM, modifying paragraph (b) to give additional
clarification on how to set the engine idle speed, adding a new
paragraph (f)(2) for testing with torque measurement at the engine's
crankshaft and how to calculate the transmission output rotational
speed, updating paragraph (j)(2) to describe how to transition between
duty cycles if the preceding cycle ends at 0 mi/hr, adding a new
paragraph (j)(5) to describe how to warm up the powertrain, adding a
new paragraph (o)(2) to describe how EPA will determine the official
fuel consumption rate during a confirmatory test, based on carbon
balance results, and updating paragraphs (o)(3) through (5) to better
define when a vehicle is not moving, moving the text from paragraph (p)
into paragraph (o)(1), moving the text of paragraph (q) to the general
provisions as a new paragraph (a)(5). The final rule includes
additional revisions regulatory text to provide greater clarity and
more carefully describe the procedures.
<bullet> Section 1037.551(b)--Updating a reference.
<bullet> Section 1037.555--Updating equations 1 and 3 to include
the appropriate variable to represent increments by italicizing the
``i''; updating a parameter name in Table 1 for consistency in this
part.
<bullet> Section 1037.560--Clarifying that it is optional to drain
gear oil after the break in period is complete, providing the option of
an alternative temperature range to provide international harmonization
of testing, editing the P<INF>loss</INF> (i.e., power loss) variable
description to improve the readability, and adding paragraph (h) to
describe how to derive axle power loss maps for untested configurations
in a family. We further modified this section in the final rule by
clarifying in paragraph (a) that for tandem axles that can be
disconnected, testing both single-drive and tandem axle configurations
includes 4x4 axles where one of the axles is disconnectable; adding a
new paragraph (h)(4) and modifying (h)(5) to address comments regarding
results when multiple gear ratios are tested and one of the points is
above the linear regression line, which could cause the regression
values to understate power loss, to clarify that you must add the
difference between the datapoint and the regression line to the
intercept values of the regression line to mitigate this effect; and
updating the use of the term ``axle'' to ``axle assembly'' throughout
the section to provide consistency.
<bullet> Section 1037.565--Providing an option to map additional
test points to provide international harmonization of testing,
including edits to improve the readability of the P<INF>loss</INF>
variable description, and adding paragraph (d)(4) and clarifying
paragraphs (e)(6) and (7) regarding the gears the transmission is
tested in. After considering comments from Allison, EMA, and Eaton
Cummins Automated Transmission Technologies, we further modified this
section by: Updating the torque transducer accuracy requirements in
paragraph (c) to link it to the highest transmission input torque or
respective output torque; adding additional detail in paragraph (d)(1)
on the maximum transmission input shaft speed to test, specifically the
maximum rated input shaft speed of the transmission or the maximum test
speed of the highest speed engine paired with the transmission. and the
minimum idle speed to test, specifically 600 r/min or the minimum idle
speed of the engines paired with the transmission; modifying paragraph
(d)(2) in response to comments regarding transmission torque setpoints
to optionally allow, in higher gear ratios where output torque may
exceed dynamometer torque limits, the use of good engineering judgment
to measure loaded test points at input torque values lower than
specified (in this case GEM may need to extrapolate values outside of
the measured map, however extrapolation time may not exceed 10% for any
given cycle and you must describe in the application for certification
how you adjusted the torque setpoints); modifying paragraph (e)(9) to
allow the use of the maximum loss value achieved from all the repeats
of the test points to calculate transmission efficiency if you cannot
meet the repeatability requirements; adding a new paragraph (e)(11)
clarifying what needs to be calculated for each point in the test
matrix; modifying paragraph (g) and moving part of existing paragraph
(g) to a new paragraph (h) to avoid a potentially never-ending cycle of
repeat testing if repeatability requirements are not achieved. If the
repeatability requirement is not met after conducting three or more
tests, the maximum loss value may be used to calculate transmission
efficiency, or you can continue to test until you pass the
repeatability requirement.
<bullet> Section 1037.570--Adding new section to characterize
torque converters to allow a manufacturer to determine their own torque
converter capacity factor instead of using the default value provided
in GEM. The option to use the default value remains. The final rule
includes updated regulatory text to provide greater clarity and more
carefully describe the procedures. Final revisions do not change the
proposed procedure; instead, they include updates to revise the section
heading, reorganize paragraphs, ensure consistent terminology, and
clarify measurement points.
3. 40 CFR Part 1065 Test Procedures
EPA proposed several updates to the testing and measurement
provisions of 40 CFR part 1065 related to how to measure emissions from
heavy-duty highway and nonroad engines and requested comment on general
improvements to the engine test procedures and compliance provisions
(see 85 FR 28142). This section presents the changes we are adopting
primarily to reduce variability associated with engine test procedures
after consideration of comments received. Chapter 2 of our Response to
Comments includes additional details on some of these amendments, as
well as other testing and measurement amendments or clarifications
requested by commenters and our responses.
[[Page 34314]]
The regulations in part 1065 rely heavily on acronyms and
abbreviations (see 40 CFR 1065.1005 for a complete list). Acronyms used
here are summarized in Table II-1:
Table II-1--Summary of Acronyms Related to 40 CFR Part 1065 That Are
Referenced in These Amendments
------------------------------------------------------------------------
------------------------------------------------------------------------
ASTM............................. American Society for Testing and
Materials
CVS.............................. Constant-Volume Sampler
DEF.............................. Diesel Exhaust Fluid
ECM.............................. Electronic Control Module
NIST............................. National Institute for Standards and
Technology
NMC FID.......................... Nonmethane Cutter with a Flame
Ionization Detector
NMHC............................. Nonmethane Hydrocarbon
NMNEHC........................... Nonmethane Nonethane Hydrocarbon
RMC.............................. Ramped Modal Cycle
THC FID.......................... Flame Ionization Detector for Total
Hydrocarbons
------------------------------------------------------------------------
We are generally finalizing revisions as proposed; however, some
revisions include further changes and clarifications after
consideration of public comments to better ensure clarity, accuracy and
consistency with the intent of the proposed rule.
<bullet> Section 1065.1(g)--Updating the test procedure Uniform
Resource Locator (URL).
<bullet> Section 1065.2(c)--Correcting a typographical error by
replacing ``engines'' with ``engine''.
<bullet> Section 1065.130(e)--Revising to denote that a carbon
balance procedure should be performed to verify exhaust system
integrity in place of a chemical balance procedure.
<bullet> Section 1065.140(c)(6)(i)--Correcting a typographical
error by replacing ``dew point'' with ``dewpoint''.
<bullet> Section 1065.140(e)(2)--Clarifying how to determine the
minimum dilution ratio for discrete mode testing.
<bullet> Section 1065.145(e)(3)(i)--Removing the requirement to
heat a sample pump if it is located upstream of a NO<INF>X</INF>
converter or chiller and replacing it with a requirement to design the
sample system to prevent aqueous condensation to better address
concerns with the loss of NO<INF>2</INF> in the sampling system where
methods other than heating the pump can be used to prevent
condensation.
<bullet> Section 1065.170--Updating to allow you to stop sampling
during hybrid tests when the engine is off and allow exclusion of the
sampling off portions of the test from the proportional sampling
verification, and adding a provision for hybrid testing to allow
supplemental dilution air to be added to the bag in the event that
sampled volumes are too low for emission analysis.
<bullet> Section 1065.205 introductory and Table 1--Revising and
adding recommended performance specifications for fuel and DEF mass
scales and flow meters to reduce fuel flow measurement error.
<bullet> Section 1065.220(a) introductory and (a)(3)--Updating the
application of fuel flow meters to more correctly reflect how and what
they are used for in part 1065.
<bullet> Section 1065.225(a) introductory and (a)(3)--Updating the
application of intake flow meters to more correctly reflect how and
what they are used for in part 1065.
<bullet> Section 1065.247--Revising to add acronym for DEF
throughout in place of ``diesel exhaust fluid'' and in paragraph (c)(2)
account for any fluid that bypasses or returns from the dosing unit to
the fluid storage tank.
<bullet> Section 1065.260(e)--Adding the word ``some'' as a
qualifier for gaseous fueled engines with respect to using the additive
method for NMHC determination.
<bullet> Section 1065.266(a) and (b)--Adding flexible fuel engines
under the allowance to use Fourier transform infrared (FTIR) and
updating the URL for EPA method 320.
<bullet> Section 1065.275--Deleting the URL and replacing with a
reference to Sec. 1065.266(b).
<bullet> Section 1065.280(a)--Updating to reflect that there is no
method in Sec. 1065.650 for determining oxygen balance and that you
may develop a method using good engineering judgment.
<bullet> Section 1065.303 Table 1--Updating the formatting and
entries in the summary table to reflect revised requirements, including
adding fuel mass scale and DEF mass scale to the linearity
verifications in Sec. 1065.307, updating the verification in Sec.
1065.341 to replace ``batch sampler'' with ``PFD'' as partial-flow
dilution (PFD) is the preferred language, updating one footnote to
include the PFD flow verification (propane check) as not being required
for measurement systems that are verified by a carbon balance error
verification as described in Sec. 1065.341(h) and adding two footnotes
excluding linearity verification for DEF flow if the ECM is used and
for intake air, dilution air, diluted exhaust, batch sampler, and raw
exhaust flow rates flow if propane checks or carbon balance is
performed. These are not new exemptions; they are simply relocated to
the footnotes.
<bullet> Section 1065.307(c)(13)--Adding a clarification that the
calculation used for arithmetic mean determination in Sec. 1065.602
uses a floating intercept.
<bullet> Section 1065.307(d)(4)--Revising to include DEF mass flow
rate and to correct or account for buoyancy effects and flow
disturbances to improve the flow measurement.
<bullet> Section 1065.307(d)(6)(i)--Revising to state that the span
gas can only contain one single constituent in balance air (or
N<INF>2</INF> if using a gas analyzer) as the reference signal for
linearity determination.
<bullet> Section 1065.307(d)(7)--Revising to state that the span
gas can only contain one single constituent in balance air (or
N<INF>2</INF> if using a gas analyzer) as the reference signal for
linearity determination.
<bullet> Section 1065.307(d)(9)--Expanding the paragraph to include
fuel and DEF mass scales and requirements for performing the linearity
verification on these scales.
<bullet> Section 1065.307(e)(3)(i) and (ii)--Editing to clarify the
intent of the requirements.
<bullet> Section 1065.307(e)(3)(iii) through (xi)--Defining maximum
flowrate for fuel and DEF mass scales and flow meters as well as
maximum molar flowrate for intake air and exhaust flow meters and
defining maximum for electrical power, current, and voltage
measurement.
<bullet> Section 1065.307(e)(5)--Providing additional information
surrounding requirements for using a propane check or carbon balance
verification in place of a flow meter linearity verification.
<bullet> Section 1065.307(e)(7)(i)(F) and (G)--Adding transmission
oil and axle gear oil to temperature measurements that require
linearity verification.
<bullet> Section 1065.307(f)--Adding new paragraph (f) to denote
that table 1 follows.
<bullet> Section 1065.307 Table 1--Adding DEF flow rate, fuel mass
scale, and DEF mass scale to measurement systems and updating the
footnote format.
<bullet> Section 1065.307(g)--Adding a new paragraph (g) to denote
that table 2 follows.
<bullet> Section 1065.307 Table 2--Adding a new Table 2 to provided
additional guidance on when optional verifications to the flow meter
linearity verifications can be used.
<bullet> Section 1065.309(d)(2)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
from EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.320(b)--Deleting existing paragraph (b) and
marking it
[[Page 34315]]
``reserved'' as this is now adequately covered in Sec. 1065.307.
<bullet> Section 1065.341--Revising section heading, adding
introductory text, revising paragraph (a) to clarify which
subparagraphs apply to CVS and which apply to PFD, relocating some of
existing paragraph (a) to paragraph (f) and reordering existing
paragraphs (b) through (f) as paragraphs (a) through (e).
<bullet> Section 1065.341(g)--Revising to replace ``batch sampler''
with ``PFD'' throughout and editing to provide further clarification on
the procedure.
<bullet> Section 1065.341(h)--Adding a new paragraph to reference
Table 2 of Sec. 1065.307 regarding when alternate verifications can be
used.
<bullet> Section 1065.342(d)(2)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
by EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.350(d)(2)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
by EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.355(d)(2)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
by EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.360(a)(4)--Adding a new option to determine
methane and ethane THC FID response factors as a function of exhaust
molar water content when measuring emissions from a gaseous fueled
engine. This is to account for the effect water has on non-methane
cutters. We received a comment regarding whether the new regulatory
text for the allowance is optional. The intent is that if you decide to
use the option to determine the methane and ethane THC FID response
factors as a function of exhaust molar water content, you must generate
and verify the humidity as described in Sec. 1065.365(d)(12).
Paragraph (a)(4) has been modified to make this clear.
<bullet> Section 1065.360(d)(12)--Adding a process to determine
methane and ethane THC FID response factors as a function of exhaust
molar water content when measuring emissions from a gaseous fueled
engine. This is to account for the effect water has on non-methane
cutters.
<bullet> Section 1065.365(a)--Removing chemical symbol for methane
in parenthetical.
<bullet> Section 1065.365(d)--Adding a requirement to determine NMC
FID methane penetration fraction and ethane response factor as a
function of exhaust molar water content when measuring emissions from a
gaseous fueled engine. This is to account for the effect water has on
non-methane cutters.
<bullet> Section 1065.365(d)(9)--Adding C<INF>2</INF>H<INF>6</INF>
before ``response factor'' and ``penetration fraction'' to clarify, as
intended, that these are the ethane response factor and ethane
penetration fraction.
<bullet> Section 1065.365(d)(10), (11), and (12)--Adding a process
to determine NMC FID methane penetration fraction and ethane response
factors as a function of exhaust molar water content when measuring
emissions from a gaseous fueled engine. This is to account for the
effect water has on non-methane cutters.
<bullet> Section 1065.365(f)(9) and (14)--Adding
C<INF>2</INF>H<INF>6</INF> before ``response factor'' and ``penetration
fraction'' to clarify, as intended, that these are the ethane response
factor and ethane penetration fraction. Adding CH<INF>4</INF> before
``penetration fraction'' to clarify, as intended, that this is the
methane penetration fraction.
<bullet> Section 1065.370(e)(5)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
by EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.375(d)(2)--Updating to allow the use of water
vapor injection for humidification of gases. After considering comments
by EMA and Auto Innovators, we further modified this section to make
language consistent where water vapor injection was added as an
alternative.
<bullet> Section 1065.410(c)--Replacing ``bad engine'' with
``malfunctioning'' in relation to engine components after considering a
comment by Auto Innovators.
<bullet> Section 1065.410(d)--Updating to state that you may repair
a test engine if the parts are unrelated to emissions without prior
approval. If the part may affect emissions, prior approval is required.
<bullet> Section 1065.510(a), (b)(5)(i), (c)(5), and (f)(4)(i)--
Moving provision for engine stabilization during mapping from Sec.
1065.510(a) to Sec. 1065.510(b)(5)(i), which lays out the mapping
procedure, adding allowance in Sec. 1065.510(f)(4)(i) to specify curb
idle transmission torque (CITT) as a function of idle speed in cases
where an engine has an adjustable warm idle or enhanced idle. We
further modified this section in the final rule by adding a provision
in Sec. 1065.510(c)(5) for hybrid powertrain testing to map negative
torque required to motor the engine with the RESS fully charged.
<bullet> Section 1065.512(b)(1) and (2)--Updating procedures on how
to operate the engine and validate the duty-cycle when an engine
utilizes enhanced-idle speed. This also addresses denormalization of
the reference torque when enhanced-idle speed is active.
<bullet> Section 1065.514(e)--Clarifying that a floating intercept
as described in Sec. 1065.602 is used to calculate the regression
statistics to harmonize with changes made to Sec. 1065.602 and further
modifying paragraph (e)(3) in the final rule to change ``standard
estimates of errors'' to ``standard error of the estimate'' for
consistency with other parts.
<bullet> Section 1065.514 Table 1--Updating a parameter name in the
final rule for consistency with other parts.
<bullet> Section 1065.530(a)(2)(iii)--Adding instructions on how to
determine that the engine temperature has stabilized for air cooled
engines.
<bullet> Section 1065.530(g)(5)--Adding a new paragraph on carbon
balance error verification if it is performed as part of the test
sequence.
<bullet> Section 1065.543--Adding a new section on carbon balance
error verification procedure to further reduce measurement variability
for the fuel mapping test procedure in part 1036. We have further
modified this section in the final rule to make it optional to account
for the flow of other non-fuel carbon-carrying fluids into the system
as the overall contribution from any such fluids to the total carbon in
the system is negligible.
<bullet> Section 1065.545--Revising to clarify that a forcing the
intercept through zero as described in Sec. 1065.602 is used to
calculate the standard error of the estimate (SEE) to harmonize with
changes to Sec. 1065.602.
<bullet> Section 1065.602(b), (c), (d), (e), (f), (g), (h), (j),
(k)--Updating to include the appropriate variable to represent
increments by italicizing the ``i''.
<bullet> Section 1065.602 Table 1--Updating footnote format in
table.
<bullet> Section 1065.602 Table 2--Correcting a typographical error
where the N<INF>ref</INF>-1 value should be ``22'' but was mistakenly
listed as ``20''.
<bullet> Section 1065.602(h)--Defining the existing Equation
1065.602-9 as a least squares regression slope calculation where the
intercept floats, i.e., is not forced through zero, designating this
[[Page 34316]]
paragraph as (h)(1) and adding a new paragraph (h)(2) for Equation
1065-602-10, a least squares regression slope calculation where the
intercept is forced through zero.
<bullet> Section 1065.602(i)--Editing to state that the intercept
calculation Equation 1065.602-11 is for a floating intercept.
<bullet> Section 1065.602(j)--Defining the existing Equation
1065.602-12 (renumbered from 1065.602-11) as a SEE calculation where
the intercept floats, i.e., is not forced through zero, designating
this paragraph as (j)(1), adding a new paragraph (j)(2) for Equation
1065.602-13, a SEE calculation where the intercept is forced through
zero, and further modifying paragraph (j) in the final rule to change
``Standard estimate of error'' to ``Standard error of the estimate''
for consistency with other parts.
<bullet> Section 1065.610(a)(1)(iv)--Updating to include the
appropriate variable to represent increments by italicizing the ``i''.
<bullet> Section 1065.610(a)(2)--Clarifying that the alternate
maximum test speed determined is for all duty-cycles.
<bullet> Section 1065.610(d)(3)--Adding provision to use good
engineering judgment to develop an alternate procedure for adjusting
CITT as a function of speed.
<bullet> Section 1065.640(a), (b)(3), and (d)(1)--Deleting a comma
in paragraph (a), specifying that the least square regression
calculation in paragraph (b)(3) is with a floating intercept, providing
a conversion to kg/mol for M<INF>mix</INF> in the example problem for
paragraph (d)(1), and correcting an error in the example problem in
applying Equation 1065.640-10 where M<INF>mix</INF> was used with the
wrong units.
<bullet> Section 1065.640(d)(3)--Providing additional guidance on
how to calculate SEE for C<INF>d</INF> to correspond with the changes
made to Sec. 1065.602.
<bullet> Section 1065.642(b)--Correcting a cross-reference.
<bullet> Section 1065.642(c)(1)--Defining C<INF>f</INF>.
<bullet> Section 1065.643--Adding a new section on carbon balance
error verification calculations to support the new Sec. 1065.543.
<bullet> Section 1065.650(b)(3)--Adding DEF to clarify what is
needed for chemical balance calculations.
<bullet> Section 1065.650(c)(1)--Relocating transformation time
requirement from Sec. 1065.650(c)(2)(i) to Sec. 1065.650(c)(1).
<bullet> Section 1065.650(c)(3)--Updating the equation to include
the appropriate variable to represent increments by italicizing the
``i''.
<bullet> Section 1065.650(d)--Correcting cross-references.
<bullet> Section 1065.650(d)(7)--Updating to include the
appropriate variable to represent increments by italicizing the ``i''.
<bullet> Section 1065.650(f)(2)--Adding DEF to clarify what is
needed for chemical balance calculations.
<bullet> Section 1065.650(g)--Updating the equations to include the
appropriate variable to represent increments by italicizing the ``i''
and correcting variable name from e<INF>NOxcomposite</INF> to
e<INF>NOxcomp</INF>.
<bullet> Section 1065.655--Adding ``DEF'' to the section heading.
<bullet> Section 1065.655(a) and (c) introductory text--After
considering comments by EMA, we modified this section to clarify that
the inclusion of diesel exhaust fluid in the chemical balance is
optional.
<bullet> Section 1065.655(c)(3)--Updating the x<INF>Ccombdry</INF>
variable description to include injected fluid.
<bullet> Section 1065.655(d)--After considering comments by EMA, we
modified this section to clarify that the inclusion of diesel exhaust
fluid in the wC determination is optional.
<bullet> Section 1065.655(e)(1)(i)--Clarifying the determination of
carbon and hydrogen mass fraction of fuel, specifically to S and N
content.
<bullet> Section 1065.655(e)(3)--Clarifying that nonconstant fuel
mixtures also applies to flexible fueled engines.
<bullet> Section 1065.655(e)(4)--Updating to include the
appropriate variable to represent increments by italicizing the ``i''.
<bullet> Section 1065.655(e)(5)--Adding new paragraph (e)(5) to
denote that table 1 follows.
<bullet> Section 1065.655 Table 1--Updating cross-reference.
<bullet> Section 1065.655(f)(3)--Restricting the use of Equation
1065.655-25 if the standard setting part requires carbon balance
verification and including the appropriate variable to represent
increments by italicizing the ``j''; adding in the final rule a
description of the variable for carbon mass fraction, as it was
missing.
<bullet> Section 1065.655(g)(1)--Updating cross-reference.
<bullet> Section 1065.659(c)(2) and (3)--Adding DEF to clarify what
is needed for chemical balance chemical balance calculations.
<bullet> Section 1065.660(a)(5) and (6)--Adding new paragraphs to
those proposed codifying existing practice to calculate THC based on
measurements made with FTIR for gaseous fueled engines. EPA intended in
previous updates to part 1065 to allow the determination of NMNEHC and
NMHC using FTIR from gaseous fueled engines, but the HD Phase 2
rulemaking inadvertently omitted instructional text in paragraph (a) on
calculating THC using the two FTIR additive methods.
<bullet> Section 1065.660(b)(2) and (3)--Correcting typographical
errors, including adding missing commas.
<bullet> Section 1065.660(b)(4)--Correcting a typographical error
for the chemical formula of acetaldehyde in a variable.
<bullet> Section 1065.660(c)(2)--Including NMC FID as allowable
option in NMNEHC calculation and further modifying Sec. 1065.660(c) in
the final rule adding additional information on performing the NMNEHC
calculation and to correct typos in variables.
<bullet> Section 1065.660(d)--Adding missing parentheses.
<bullet> Section 1065.665(a)--Deleting the variable and description
for C# as it is not used in any calculation in this section.
<bullet> Section 1065.667(d)--Adding DEF to clarify what is needed
for chemical balance description.
<bullet> Section 1065.675(d)--Editing variable descriptions to
refer to a humidity generator rather than a bubbler (accommodates both
a bubbler and humidity generator).
<bullet> Section 1065.695(c)(8)(v)--Adding carbon balance
verification.
<bullet> Section 1065.701(b)--Updating name of California gasoline
type.
<bullet> Section 1065.701 Table 1--Updating footnote format in
table.
<bullet> Section 1065.703 Table 1--Updating to correct units for
kinematic viscosity and updating footnote format in table.
<bullet> Section 1065.705 Table 1--Updating to correct units for
kinematic viscosity and updating footnote format in table.
<bullet> Section 1065.710 Table 1--Editing format for consistency
and updating footnote format in table.
<bullet> Section 1065.710 Table 2--Editing format for consistency,
adding allowance to use ASTM D1319 or D5769 for total aromatic content
determination and ASTM D1319 or D6550 for olefin determination because
the dye used in ASTM D1319 is becoming scarce and an alternate method
is needed, and updating a footnote format in table.
<bullet> Section 1065.715 Table 1--Updating footnote format in
table.
<bullet> Section 1065.720 Table 1--Updating footnote format in
table and revising Table 1 after considering a comment by EMA to
specify ASTM D6667 instead of ASTM D2784 as the reference procedure for
measuring sulfur in liquefied petroleum gas. We requested comment on
amending the
[[Page 34317]]
regulation to replace ASTM D2784, which has been withdrawn by ASTM
without replacement, received comment from EMA and agree that ASTM
D6667 is a suitable method. EPA is similarly changing other regulatory
provisions to specify ASTM D6667 as the reference procedure for fuel
manufacturers measuring sulfur in butane (see 40 CFR 1090.1350).
<bullet> Section 1065.750 Table 1--Updating footnote format in
table.
<bullet> Section 1065.790(b)--Adding a NIST traceability
requirement for calibration weights for dynamometer, fuel mass scale,
and DEF mass scale.
<bullet> Section 1065.905 Table 1--Updating footnote format in
table.
<bullet> Section 1065.910(a)(2)--Adding a revision in the final
rule to change the requirement to use 300 series stainless steel tubing
to connect the PEMS exhaust and/or intake air flow meters into a
recommendation because there are other materials that are equally
suitable for in-use testing other than stainless steel tubing.
<bullet> Section 1065.915 Table 1--Updating footnote format in
table.
<bullet> Section 1065.1001--Adding a definition for enhanced-idle.
<bullet> Section 1065.1001--Clarifying definition of test interval
as duration of time over which the mass of emissions is determined.
<bullet> Section 1065.1005(a)--Updating footnote format in table
and parameter names for consistency with other parts.
<bullet> Section 1065.1005(c), (d), and (e)--Updating to ensure
column headings use terminology consistent with NIST SP-811.
<bullet> Section 1065.1005(a) and (e)--Updating tables of symbols
and subscripts to reflect revisions to part 1065.
<bullet> Section 1065.1005(f)(2)--Adding molar mass of ethane and
updating footnote format in table.
<bullet> Section 1065.1005(g)--Updating acronyms and abbreviations
for ASTM, e.g., and i.e.
<bullet> Section 1065.1010(b)(23) and (43)--Incorporating by
reference ASTM D6667 into the regulations instead of ASTM D2784,
consistent with replacing ASTM D2784 with ASTM D6667 as the reference
procedure for measuring sulfur in liquefied petroleum gas in Sec.
1065.720, as explained above in this section. EPA is similarly
specifying ASTM D6667 as the reference procedure for fuel manufacturers
measuring sulfur in butane.
4. 40 CFR Part 1066 Test Procedures
EPA proposed several updates to the testing and measurement
provisions of 40 CFR part 1066 related to how to measure emissions from
light- and heavy-duty vehicles and requested comment on general
improvements to the vehicle test procedures and compliance provisions
(see 85 FR 28144). This section presents the changes we are adopting to
vehicle test procedures after consideration of comments received.
Chapter 2 of our Response to Comments includes additional details on
some of these amendments, as well as other testing and measurement
amendments or clarifications requested by commenters and our responses.
We are generally finalizing revisions as proposed; however, some
revisions include further changes and clarifications after
consideration of public comments to better ensure clarity, accuracy and
consistency with the intent of the proposed rule.
<bullet> Section 1066.1(g)--Updating the URL.
<bullet> Section 1066.135(a)(1)--Revising to widen the range for
verifications of a gas divider derived analyzer calibration curve to 10
to 60% to ease lab burden with respect to the number of gas cylinders
they must have on hand and revising to make the midspan check optional
as the part 1066 requirement for yearly linearity verification of the
gas divider has provided more certainty of the accuracy of the gas
blending device.
<bullet> Section 1066.210(d)(3)--Changing the value for
acceleration of Earth's gravity from a calculation under 40 CFR
1065.630 to a default value of 9.80665 m/s<SUP>2</SUP> because the
track coastdown doesn't take place in the same location that the
dynamometer resides. Therefore, best practice is to use a default value
for gravity.
<bullet> Section 1066.255(c)--Clarifying that the torque transducer
zero and span are mathematically done prior to the start of the
procedure.
<bullet> Section 1066.260(c)(4)--Correcting an error in the example
problem result.
<bullet> Section 1066.265(d)(1)--Correcting example equation to
replace a subtraction sign that was a typographical error with a
multiplication sign.
<bullet> Section 1066.270(c)(4)--Correcting units for force in mean
force variable description and correcting example problem solution.
<bullet> Section 1066.270(d)(2)--Adding corrections in the final
rule of typographical errors on maximum allowable error where error
tolerances were indicated as ``<plus-minus>'', but paragraph is clear
that the allowable error is a maximum value as Equation 1066.270-2
determines error as an absolute value. Therefore, the error values are
positive and not a positive and negative range.
<bullet> Section 1066.275--Extending the dynamometer readiness
verification interval from within 1 day before testing to an optional 7
days prior to testing if historic data from the test site supports an
interval of more than 1 day. Adding corrections in the final rule of
typographical errors in paragraphs (d)(1) and (2) on allowable error
where error tolerances were indicated as ``<plus-minus>'', but
paragraph is clear that the allowable error is a maximum value as
Equation 1066.270-2 determines error as an absolute value. Therefore,
the error values are positive and not a positive and negative range.
<bullet> Section 1066.405--Updating heading to include
``maintenance''.
<bullet> Section 1066.405(a) through (c)--Designating existing text
as paragraph (a), adding new paragraphs (b) and (c) to address test
vehicle inspection, maintenance and repair, consistent with Sec.
1065.410, and, after considering a comment by Auto Innovators,
replacing ``bad engine'' with ``malfunctioning'' in relation to engine
components in paragraph (b).
<bullet> Section 1066.420 Table 1--Updating footnote format in
table and, after considering comments from Auto Innovators and VW,
clarifying that SC03 humidity tolerance is an ``average'' value
consistent with 40 CFR 86.161-00(b)(1) and inadvertently not carried
over in part 1066. All SC03 capable test cells have been designed to
meet the humidity requirement in Sec. 86.161-00 which is on an average
basis.
<bullet> Section 1066.605--Correcting a typographical error in
paragraph (c)(4) where NMHC should read NMHCE and editing Equation
1066.605-10 adding italics for format consistency.
<bullet> Section 1066.610--Editing Equation 1066.610-4 adding
italics for format consistency.
<bullet> Section 1066.710(c)--Clarifying to reflect how heating,
ventilating, and air conditioning (HVAC) control systems operate in
vehicles and how they should be operated for the test. Further
modifying paragraph (c)(1)(i)(A) in the final rule to state that for
automatic temperature control systems that allow the operator to select
a specific temperature, set the air temperature at 72 [deg]F or higher,
which the vehicle then maintains by providing air at that selected
constant temperature. Further modifying paragraph (c)(2) in the final
rule to state that for full automatic temperature control systems that
allow the operator to select a specific temperature, set the air
temperature at 72 [deg]F, which the vehicle then maintains by varying
temperature, direction and
[[Page 34318]]
speed of air flow. Clarifying terminology is consistent with EPA
compliance guidance CD-2020-04.
<bullet> Section 1066.801 Figure 1--Updating to reflect that the
initial vehicle soak, as outlined in the regulations, is a 6-hour
minimum and not a range of 6 to 36 hours.
<bullet> Section 1066.835(a)--Clarifying that the last drain and
fill operation is after the most recent FTP or highway fuel economy
test (HFET) measurement (with or without evaporative emission
measurements).
<bullet> Section 1066.835(f)(2)--Deleting the word
``instantaneous'' to reflect that the SC03 temperature and humidity
tolerances in paragraph (f)(1) are not all instantaneous in response to
comments received from Auto Innovators and Volkswagen. This was an
inadvertent error in part 1066.
<bullet> Section 1066.930--Adding a period to the end of the
sentence.
<bullet> Section 1066.1005(a)--Updating a parameter name to be
consistent with use in other parts.
<bullet> Section 1066.1005(c) and (d)--Updating to ensure column
headings use terminology consistent with NIST SP-811.
<bullet> Section 1066.1005(f)--Updating footnote format in table.
5. Greenhouse Gas Emissions Model (GEM)
EPA proposed several updates to the GEM model related to how to
measure emissions from heavy-duty engines and requested comment on
whether the differences in GEM would impact the effective stringency of
the standards and, if so, whether either GEM or the regulations need to
be revised to address the changes (see 85 FR 28145, May 12, 21020).
This section presents the changes we are adopting to GEM after
consideration of comments received. Additional details on these and
other amendments or clarifications requested by commenters and our
responses are available in Chapter 2 of our Response to Comments.
GEM is a computer application that estimates the greenhouse gas
(GHG) emissions and fuel efficiency performance of specific aspects of
heavy-duty (HD) vehicles. GEM is used to determine compliance with the
Phase 2 standards from several vehicle-specific inputs, such as engine
fuel maps, aerodynamic drag coefficients, and vehicle weight rating.
GEM simulates engine operation over two cruise cycles, one transient
cycle, and for vocational vehicles, idle operation. These results are
weighted by GEM to provide a composite GEM score that is compared to
the standard.
EPA proposed to update GEM, in a revised version 3.5 to replace the
current version 3.0, and requested comment on whether the differences
in GEM would impact the effective stringency of the standards and, if
so, whether either GEM or the regulations need to be revised to address
the changes. We received one comment on the proposal on this topic from
the California Air Resources Board (CARB), stating the importance of
GEM results being consistent with the current program standards to
ensure stringency is maintained and recommending that EPA revise GEM to
maintain this consistency.
After considering the comment and further evaluating the
performance of GEM 3.5 with the input files used to set the Phase 2
vehicle standards, EPA is finalizing GEM version 3.5.1 applicable for
MY 2021 vehicles that includes the changes proposed in version 3.5 as
well as changes that correct three errors in the GEM 3.5 code. The
following changes were proposed in version 3.5 and are finalized in
version 3.5.1 to allow additional compliance flexibilities and improve
the vehicle simulation:
<bullet> Corrected how idle emission rates are used in the model.
<bullet> Increased the allowable weight reduction range to 25,000
pounds.
<bullet> For powertrain input, added an input for powertrain rated
power to scale default engine power.
<bullet> Recalibrated driver over speed allowance on cruise cycles
from 3 mph to 2.5 mph.
<bullet> Revised engine cycle generation outputs with corrected
engine cycle generation torque output from model based on simulated
inertia and rate limited speed target.
<bullet> Added scaling of powertrain simulation default engine and
transmission maps based on new rated power input.
<bullet> Changed interpolation of fuel map used in post processing
to be consistent with one used in simulation.
<bullet> Corrected accessory load value on powertrain test when
coasting or decelerating.
<bullet> Added torque converter k-factor input option.
<bullet> Cycle average cycles: added flag for points that are to be
considered ``idle.''
<bullet> Improved handling of large input tables.
<bullet> Allow hybrid engine input.
The three additional changes in GEM 3.5.1 correct the following
errors in GEM 3.5 code: (1) A typographical error, where GEM used a
weighting factor of 0.25 instead of 0.23 for the Heavy Heavy-Duty (HHD)
Multipurpose vehicle subcategory; (2) an idle map error when the cycle
average fuel mapping procedure is used for all three drive cycles; and
(3) a functional error that unnecessarily required transmission power
loss data when using the option to enter a unique (instead of default)
k-factor for the torque converter. The GEM version we are releasing
with and incorporating by reference in this final rule is identified as
``3.5.1.''
EPA is also issuing a supplemental proposal published in the
Proposed Rules section of this issue of the Federal Register, titled
``Improvements for Heavy-Duty Engine and Vehicle Test Procedures,''
docket number EPA-HQ-OAR-2019-0307; FRL-10018-51-OAR. This supplemental
proposal provides notice and opportunity for comment on a proposed
further updated version of GEM for MY 2022 and later, proposes to allow
use of the updated model for MY 2021 for demonstrating compliance with
the Phase 2 standards, including obtaining a certificate of conformity
and submitting end-of-year reports, and requests comment on whether
this version of GEM should be required for MY2021 end-of-year reports.
This proposed revised version in the supplemental proposal includes
corrections, clarifications, additional flexibilities, and adjustment
factors to the Greenhouse gas Emissions Model (GEM) compliance tool for
heavy-duty vehicles after consideration of comments received on the
proposed rule. The supplemental proposal proposes limiting the use of
GEM 3.5.1 to MY 2021 vehicles only, except where this MY 2021 data can
be used for carryover requests for certificates of conformity for MY
2022 and future years for qualifying vehicles under Sec. 1036.235(d);
however, manufacturers would still need to use GEM 3.8 for end-of-year
reporting for MY 2022 and future years.
EPA is finalizing GEM 3.5.1 after considering comments, further
evaluating the performance of GEM 3.5.1 with the input files used to
set the Phase 2 vehicle standards, considering the corrections and
improvements made in GEM 3.5.1, and identifying potential additional
corrections and improvements for GEM. Evaluation of GEM 3.5.1 indicated
that there was some difference in output 96results for both tractor and
vocational vehicles when compared to GEM 3.0. To assess the magnitude
of any differences between using GEM 3.0 and GEM 3.5.1, we repeated the
process used in 2016 to calculate the numerical level of the vehicle
standards, replacing GEM 3.0 with GEM 3.5.1. On average, the
differences in the resulting standards
[[Page 34319]]
from using GEM 3.5.1 instead of GEM 3.0 are decreases of 0.09 percent
and 0.54 percent for the tractor and vocational vehicle standards,
respectively. The tractor standards resulting from GEM 3.5.1 ranged
from 0.29 percent below to 0.15 percent above the GEM 3.0 standards.
The vocational vehicle standards resulting from GEM 3.5.1 ranged from
0.32 percent above to 1.45 percent below the GEM 3.0 standards. A
summary of the process taken to calculate the vehicle standards using
GEM and a comparison of the results generated by GEM 3.0 and GEM 3.5.1
are provided in a docket memo.\7\
---------------------------------------------------------------------------
\7\ Sanchez, James, Memorandum to Docket EPA-HQ-OAR-2019-0307.
Process of Using GEM to Set Vehicle Standards. December 4, 2020.
---------------------------------------------------------------------------
We are finalizing GEM 3.5.1 without adopting adjustment factors in
the related test procedures.\8\ In the same memo noted previously, we
compare the GEM 3.8 results to those from GEM 3.0. In the supplemental
proposal, EPA proposes GEM 3.8 and corresponding adjustment factors to
adjust the results to more closely match the results produced by the
original GEM 3.0 version and we intend to issue a final rule before the
start of model year 2022. If finalized as proposed, we would limit the
potential impact on effective stringency due to a change in GEM
versions to model year 2021 only, which should have a minimal impact on
the effective stringency and environmental benefits of the overall
Phase 2 program.
---------------------------------------------------------------------------
\8\ Greenhouse gas Emissions Model (GEM) Phase 2, Version 3.5.1,
December 2020. A working version of this software is also available
for download at <a href="https://www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty">https://www.epa.gov/regulations-emissions-vehicles-and-engines/greenhouse-gas-emissions-model-gem-medium-and-heavy-duty</a>.
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6. Aerodynamic Test Procedures
EPA proposed several updates to the testing and modeling provisions
of 1037 subpart F related to aerodynamic testing and requested comment
on general improvements to the aerodynamic test procedures and
compliance provisions (see 85 FR 28147). This section presents the
changes we are adopting to aerodynamic test procedures after
consideration of comments received. Additional details on these and
other aerodynamic amendments or clarifications requested by commenters
and our responses are available in Chapter 2 of our Response to
Comments.
a. Aerodynamic Measurements for Tractors
The aerodynamic drag of a vehicle is determined by the vehicle's
coefficient of drag (C<INF>d</INF>), frontal area, air density and
speed. The regulations in Sec. 1037.525 allow manufacturers to use a
range of techniques, including wind tunnel testing, computational fluid
dynamics, and constant speed tests. This broad approach is appropriate
given that no single test procedure is superior in all aspects to other
approaches. However, we also recognized the need for consistency and a
level playing field in evaluating aerodynamic performance. To address
the consistency and level playing field concerns, EPA adopted an
approach that identified coastdown testing as the reference aerodynamic
test method, and specified a procedure to align results from other
aerodynamic test procedures with the reference method by applying a
correction factor (F<INF>alt-aero</INF>) to results from alternative
methods (Sec. 1037.525(b)). We are adding a sentence to the
introductory text of Sec. 1037.525 to clarify that coastdown testing
is the ``reference method for aerodynamic measurements''.
In the proposed rule, we proposed to separate Sec. 1037.525(b)(1)
into a paragraph (b)(1) defining F<INF>alt-aero</INF> and a new
paragraph (b)(2) allowing manufacturers to assume F<INF>alt-aero</INF>
is constant for a given alternate method. We are finalizing two
separate paragraphs and the subsequent renumbering of the remaining
paragraphs as proposed except as explained here. Our proposed update to
the definition of F<INF>alt-aero</INF> in Equation 1037.525-1 and the
related text in Sec. 1037.525(b)(1) inadvertently removed the
definition of effective yaw, c<INF>eff</INF>, which is used throughout
Sec. 1037.525 and incorrectly replaced the C<INF>d</INF>A variables
measured at [psi]<INF>eff</INF> with wind-averaged C<INF>d</INF>A
values, as noted in comment by EMA. We agree that Equation 1037.525-1
should continue to be based on the definition from HD GHG Phase 2 final
rule such that F<INF>alt-aero</INF> is a function of the coefficient of
drag areas at the effective yaw angle. We are finalizing paragraph
(b)(1) with the same Equation 1037.525-1 as the current requirement but
with the updated variable names throughout Sec. 1037.525 (and where
referenced in Sec. 1037.525(h)(12)(v)) to more clearly relate the drag
areas to the defined effective yaw variable, as recommended by EMA.\9\
We are also adding a ``Where:'' statement to Equation 1037.525-1 to
define the variables in that equation and are restoring the existing
language we proposed to remove that defines the effective yaw angle to
apply for Phase 1 and Phase 2 compliance.
---------------------------------------------------------------------------
\9\ The variables
C<INF>d</INF>A<INF>effective-yaw-coastdown</INF> and
C<INF>d</INF>A<INF>effective-yaw-alt</INF> are now
C<INF>d</INF>A<INF>coastdown</INF>(c<INF>eff</INF>) and
C<INF>d</INF>A<INF>alt</INF>(c<INF>eff</INF>), respectively.
---------------------------------------------------------------------------
We proposed and received no adverse comments on two additional
changes in Sec. 1037.525(b). In paragraph (b)(3), we proposed and are
finalizing removal of the sentence ``Where you have test results from
multiple vehicles expected to have the same F<INF>alt-aero</INF>, you
may either average the F<INF>alt-aero</INF> values or select any
greater value.'' By removing this statement, we are allowing
manufacturers the flexibility to propose a method for calculating their
F<INF>alt-aero</INF> from multiple test vehicles that suits their
unique compliance margin targets. In paragraph (b)(5), we proposed to
add a statement that manufacturers may test earlier model years than
the 2021, 2024, and 2027 model years specified and are finalizing
additional clarifying text and a new example. We are finalizing two
additional typographical edits correcting references to our renumbered
paragraphs in the paragraph (b)(5). The reference to ``paragraph
(b)(2)'' was corrected to paragraph (b)(3) and the reference to ``this
paragraph (b)(4)'' was corrected to paragraph (b)(5). Finally, we are
adding the phrase ``drag area from your alternate method'' to describe
the previously undefined term, C<INF>d</INF>A<INF>alt</INF>.
EPA proposed a change to Sec. 1037.525(b)(7), to clarify that the
use of good engineering judgment with respect to the specified tractor-
trailer gap dimension ``applies for all testing, including confirmatory
and SEA testing''. Both EMA and Volvo requested further clarification
through use of an example. We are finalizing three clarifying changes
to Sec. 1037.525(b)(7). First, we are adding a reference to the
tractor-trailer gap specifications in Sec. 1037.501(g)(1)(ii), as
requested. Second, we provide an example of good engineering judgment
that could be applied to correct a difference between the specified and
tested tractor-trailer gaps. Lastly, we clarify that the allowance
applies ``for certification, confirmatory testing, SEA, and all other
testing to demonstrate compliance with standards.''
We also proposed a provision to our regulations at Sec.
1037.525(b)(8) to encourage manufacturers to proactively coordinate
with EPA to have compliance staff present when a manufacturer conducts
its coastdown testing to establish F<INF>alt-aero</INF> values. Section
208 of the Clean Air Act provides EPA broad oversight authority for
manufacturer testing. Being present for the testing would give EPA
greater confidence that the test was conducted properly, and thus,
would make it less likely that EPA would need to conduct aerodynamic
confirmatory testing on the
[[Page 34320]]
vehicle. Consistent with the intent of the proposed revision and EPA's
authority under section 208, we are finalizing in Sec. 1037.525(b)(8)
a provision that refers to the existing preliminary approval provisions
of Sec. 1037.210 with the note that EPA may witness the testing.
Section 1037.210 provides an established protocol for manufacturers to
coordinate with EPA for testing.
EMA's comment requested additional modifications to the yaw sweep
correction provisions in Sec. 1037.525(c), suggesting that coastdown
results do not need to be corrected to wind-averaged and that all of
paragraph (c)(2) was ``unnecessary'' because another regulatory
provision ``serves that function''. Their request appears to be a
misunderstanding of the existing regulations. Wind-averaged drag area
(C<INF>d</INF>A<INF>wa</INF>) is a required input for GEM in Phase 2.
Paragraph (c)(1) specifies how to calculate C<INF>d</INF>A<INF>wa</INF>
when using an alternate test method and paragraph (c)(2) specifies how
to calculate it for coastdown testing. EPA may use coastdown for
confirmatory testing and manufacturers may choose to use coastdown
testing for all aerodynamic testing. Consequently, paragraph (c)(2) is
needed to properly calculate the wind-averaged input required by GEM in
these situations. To address any potential confusion on the necessity
of both paragraphs under the current regulatory text, we are finalizing
three updates to Sec. 1037.525(c) as follows:
<bullet> Clarifying the use of the yaw correction provisions by
revising paragraph (c) introductory text to add ``as specified in Sec.
1037.520'' and to remove the phrase ``differences from coastdown
testing'' that only applies to paragraph (c)(1).
<bullet> Updating the text of paragraphs (c)(1) and (2) to more
clearly communicate that they are two separate options that apply based
on which testing method is chosen.
<bullet> Adopting the updated drag area variable names from Sec.
1037.525(b).
b. Aerodynamic Measurements for Vocational Vehicles
We did not specifically propose changes to or request comment on
our procedures for measuring aerodynamic performance of vocational
vehicles in Sec. 1037.527. EMA commented that the existing provisions
of Sec. 1037.527 to determine a DC<INF>d</INF>A value for vocational
vehicles refer to the trailer provisions in Sec. 1037.526; however,
Sec. 1037.526 does not specify how to choose an appropriate baseline
for vocational vehicles. EMA requested that manufacturers should be
able to ``choose an appropriate baseline vehicle for the technology and
applications''. We are not taking any final action on this issue at
this time. However, we are providing a summary of the current
provisions and their original intent in this preamble to assist
manufacturers.
The current Sec. 1037.527(a) states that DC<INF>d</INF>A is
determined for vocational vehicles as follows: ``Determine
DC<INF>d</INF>A values by performing A to B testing as described for
trailers in Sec. 1037.526, with any appropriate adjustments,
consistent with good engineering judgment.'' The A to B testing
provisions for trailers are specified in Sec. 1037.526(a), where
paragraph (a)(1) describes the baseline trailer, paragraph (a)(2)
describes the general intent of the A to B test, and paragraph (a)(3)
describes how to calculate the DC<INF>d</INF>A from the test results.
We acknowledge that the reference to a ``standard trailer'' in
Sec. 1037.526(a)(1) may cause confusion to vocational vehicle
manufacturers, since it would be a challenge to identify a single
``standard'' vehicle to represent the range of vocational applications.
However, the baseline trailer description in that paragraph equates to
a trailer without aerodynamic components, which is the key aspect of
that baseline description the regulatory cross-reference in Sec.
1037.527(a) applies to vocational vehicles. The trailer provision of
Sec. 1037.526(a)(2) states that the general intent of the A to B test
is to ``demonstrate the reduction in aerodynamic drag associated with
the improved design'', which can be directly applied to vocational
vehicles. The general process of calculating DC<INF>d</INF>A in Sec.
1037.526(a)(3) could be applied to vocational vehicles as well, but its
reference to test trailer and baseline trailer may cause confusion for
reasons similar to those discussed for Sec. 1037.526(a)(1).
Similar to the trailer provision, a vocational vehicle's
aerodynamic performance is based on a DC<INF>d</INF>A value relative to
a baseline vehicle. Manufacturers wishing to perform aerodynamic
testing on their vocational vehicles are encouraged to coordinate with
their Designated Compliance Officer and use the existing provision in
Sec. 1037.527, including its reference to the description of how to do
so for the trailer-specific provision in Sec. 1037.526. As noted in
Sec. 1037.527(a), we expect manufacturers to make ``appropriate
adjustments'' when applying the cross-referenced provision to
vocational vehicle testing consistent with good engineering judgment.
When followed, this should result in a manufacturer choosing an
appropriate baseline vehicle, similar to the clarification requested by
the commenter. For example, a manufacturer may choose an aerodynamic
test method, determine a baseline C<INF>d</INF>A value (in m\2\) using
a vehicle that represents a production configuration without the
aerodynamic improvement, then repeat the same aerodynamic method for a
test vehicle that is a nearly equivalent configuration but includes the
aerodynamic improvement of interest. In this case, the manufacturer
would calculate DC<INF>d</INF>A by subtracting the measured drag area
for the test vehicle from the drag area for the baseline vehicle.
Calculating DC<INF>d</INF>A in this manner would generally be
consistent with the intent that the test ``accurately demonstrate the
reduction in aerodynamic drag associated with the improved design'' for
the vocational vehicle since any improvement to aerodynamic performance
would be attributable to the aerodynamic technology on the test
vehicle.
c. Computational Fluid Dynamics Procedures
We proposed one correction to our computational fluid dynamics
(CFD) provisions of Sec. 1037.532 that replaced the incorrect ``or''
in paragraph (a)(1) with ``and'' to include yaw angles of +4.5[deg] and
-4.5[deg]. EMA requested three additional modifications related to our
CFD provisions. In Sec. 1037.532(a)(3), they requested that we clarify
our specified Reynolds number of 5.1 million is based on the 102-inch
trailer width as the characteristic length. We agree with this
suggestion and updated the language in Sec. 1037.532(a)(3) for clarity
that the Reynolds number is based on a 102-inch trailer width
consistent with our specifications for a ``standard trailer'' in Sec.
1037.501(g)(1)(i). EMA also suggested the phrase ``the General On-Road
Simulation'' in Sec. 1037.532(a)(4) be replaced with ``an open-road
simulation'' to avoid confusion with SAE International's revisions of
SAE J2966 to incorporate the impact of traffic. We agree that open-road
simulation is representative of our initial intent and are updating the
regulatory text of Sec. 1037.532(a)(4). See Chapter 2 of our Response
to Comments for additional details.
EMA's third request was that we remove the requirement to set the
``free stream turbulence intensity to 0.0 percent'' in Sec.
1037.532(a)(5), and instead recommended we replace that requirement
with a ``uniform inlet velocity profile.'' EPA is not taking any final
action on revision to that paragraph at this time. Furthermore, EPA
disagrees with the requested change to paragraph (a)(5). Turbulence
intensity is a common parameter in CFD packages and, as described in
Chapter
[[Page 34321]]
3.2.2.3 of the Final Regulatory Impact Analysis (Final RIA) for the HD
Phase 2 Rule, we evaluated a range of turbulence intensities and
intentionally specified a value of zero to ensure consistency, stating
that ``Turbulence intensity must be 0.0 percent.'' \10\ Manufacturers
who wish to use alternative parameters and criteria related to their
CFD models, which includes seeking to substitute the specified
turbulence intensity with a uniform inlet velocity profile, continue to
have the option to seek to do so through requesting EPA approval under
Sec. 1037.532(f).
---------------------------------------------------------------------------
\10\ US EPA, US DOT/NHTSA. Greenhouse Gas Emissions and Fuel
Efficiency Standards for Medium- and Heavy-Duty Engines and
Vehicles--Phase 2: Regulatory Impact Analysis. EPA-420-R-16-900.
August 2016. Page 3-41.
---------------------------------------------------------------------------
CARB requested EPA add provisions that set a requirement for a
maximum limit of computational elements to perform Computational Fluid
Dynamics (CFD) simulation, define a specific transient averaging
methodology, quantify the uncertainty in using CFD simulation, and
assess CFD simulation credibility. We are not taking any final action
on these requests, but may consider the changes suggested by the
commenter in an appropriate future rulemaking with notice and comment.
See our complete response in Chapter 2 of our Response to Comments.
7. Hybrid Powertrain Test Procedures
As explained above in Sections II.A.1 and II.A.2, EPA proposed
several updates to the hybrid powertrain test procedures that apply to
engine and vehicle standards provisions in 40 CFR 1036.503, 1036.505,
1036.510, and 1036.527, 40 CFR part 1036, appendix B, and 40 CFR
1037.550 related to how to perform hybrid powertrain testing and
requested comment on general improvements to the hybrid powertrain test
procedure provisions (see 85 FR 28152). This section further explains,
in addition to the specific descriptions in Sections II.A.1. and
II.A.2. above, the changes we are adopting to hybrid powertrain test
procedures after consideration of comments received. Additional details
on these and other hybrid powertrain testing and measurement amendments
or clarifications requested by commenters and our responses are
available in Chapter 2 of our Response to Comments.
a. Hybrid Test Procedures for Engine Standards
EPA worked with industry prior to proposal and also considered
input provided during this rulemaking to develop a powertrain test
procedure that includes the addition of a transmission model to GEM and
options in GEM to test without the transmission present, using the
model in its place to be used to certify a hybrid powertrain to the FTP
and SET HD GHG Phase 2 greenhouse gas engine standards. The two primary
goals of this development process were to make sure that the powertrain
version of each test cycle was equivalent to the respective engine
cycle in terms of positive power demand versus time and that the
powertrain cycle had appropriate levels of negative power demand.
Our current regulations do not have a certification procedure for
powertrain certification of heavy-duty hybrid vehicles to any engine
standards. The powertrain certification test for certification to both
the FTP and SET is carried out by following 40 CFR 1037.550 as
described in 40 CFR 1036.505 and 1036.510 and is applicable for
powertrain systems located in the P0, P1, P2, and P3 positions.
For this test procedure, EPA is finalizing addition of a vehicle
speed and road grade profile to the existing FTP duty cycles for
compression-ignition and spark-ignition engines in 40 CFR part 1036,
appendix B, and to the SET duty cycle in 40 CFR 1036.505. EPA also is
finalizing vehicle parameters to be used in place of those in 40 CFR
1037.550; namely vehicle test mass, vehicle frontal area, vehicle drag
area, coefficient of rolling resistance, drive axle ratio, tire radius,
vehicle curb mass, and linear equivalent mass of rotational moment of
inertias. Under the final test procedure, determination of system and
continuous rated power along with the maximum vehicle speed (C speed)
is also required using 40 CFR 1036.527. Under the final test procedure,
the combination of the generic vehicle parameters, the engine duty-
cycle vehicle speed profile, and road grade profile fully defines the
system load and this is designed to match up the powertrain load with
the compression-ignition engine vFTP, spark ignition engine vFTP, and
vSET load for an equally powered engine.
The development of this test procedure was based on the process
contained in Global Technical Regulation No. 4.<SUP>11 12</SUP>
Generally speaking, the final test procedure is powertrain in the loop
using a vehicle-based cycle (vehicle speed vs. time and grade vs.
time). The final vehicle speed profiles were developed by following SAE
2012-01-0878.\13\
---------------------------------------------------------------------------
\11\ United Nations Economic Commission for Europe. Addendum 4:
Global technical regulation No. 4. Test procedure for compression
ignition (C.I.) engines and positive-ignition (P.I.) engines fueled
with natural gas (NG) or liquefied petroleum gas (LPG) with regard
to the emission of pollutants Amendment 3., March 12, 2015.
\12\ Six, C., Siberholz, G., Fredriksson, J., Geringer, B.,
Hausberger, S. Development of an exhaust emission and CO2
measurement test procedure for heavy-duty hybrids (HDH). October 27,
2014. Available online at: <a href="https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2">https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2</a>.
\13\ Andreae, M., Salemme, G., Kumar, M., and Sun, Z.,
``Emissions Certification Vehicle Cycles Based on Heavy Duty Engine
Test Cycles,'' SAE Int. J. Commer. Veh. 5(1):299-309, 2012, <a href="https://doi.org/10.4271/2012-01-0878">https://doi.org/10.4271/2012-01-0878</a>.
---------------------------------------------------------------------------
The engine operational profile for engines installed in vehicles
depends on the entire vehicle setup, including the use of hybrid
systems if applicable, thus the entire vehicle must be considered when
certifying a powertrain. Given that heavy duty vehicles can vary quite
a bit even though the powertrain configuration remains unchanged,
testing of every conceivable configuration is not possible; therefore,
a representative average vehicle, consisting of generic vehicle
parameters, is used to provide a representative configuration for
certification testing. Generic vehicle parameters were developed with
the intent of maintaining the same system load for engines installed in
conventional vehicles and hybrid systems with the same power rating to
maintain comparability in terms of emissions.\14\
---------------------------------------------------------------------------
\14\ Six, C., Siberholz, G., Fredriksson, J., Geringer, B.,
Hausberger, S. Development of an exhaust emission and CO2
measurement test procedure for heavy-duty hybrids (HDH). October 27,
2014. Available online at: <a href="https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2">https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2</a>.
---------------------------------------------------------------------------
EPA is finalizing vehicle parameters for hybrid powertrain testing
in place of those in 40 CFR 1037.550 to be used in the vehicle model in
40 CFR 1037.550(f). These final parameters can be found in 40 CFR
1036.505 (via reference from 40 CFR 1036.510 for FTP testing) and
included vehicle test mass, M, vehicle frontal area, A<INF>front</INF>,
vehicle drag area, C<INF>d</INF>A, coefficient of rolling resistance,
C<INF>rr</INF>, drive axle ratio, k<INF>a</INF>, tire radius, r,
transmission efficiency if the hybrid powertrain is being tested
without the transmission, axle efficiency, Eff<INF>axle</INF>, vehicle
curb mass, M<INF>curb</INF>, and linear equivalent mass of rotational
moment of inertias, M<INF>rotating</INF>. The requirements for the
determination of these parameters were taken from the Global Technical
Regulation (GTR) No. 4 referenced above.
Under the final test procedure, to align the system demands for
conventional and hybrid engines, the generic vehicle parameters are
defined as a function of the system's power
[[Page 34322]]
rating. 40 CFR 1036.527 provides the procedure for determining the peak
rated power, P<INF>rated</INF>, and continuous rated power of the
hybrid system, P<INF>contrated</INF>, that goes into the vehicle test
mass determination. These revisions also provide a procedure for the
determination of the maximum vehicle speed (C speed), vrefC. In
general, the process for determining both P<INF>rated</INF> and
P<INF>contrated</INF> is very similar to the GTR No. 4 hybrid system
rated power determination procedure with a few exceptions. In the final
40 CFR 1036.527 procedure, the default axle efficiency is 0.955 because
that is the default value in GEM. The determination of continuous rated
power in the final EPA process versus the system rated power in the GTR
No. 4 process is to address the lack of a steady state vehicle test
cycle in GTR No. 4. The full throttle test to determine system rated
power in GTR No. 4 lasts 50 to 150 seconds and GTR No. 4 determines
rated power as peak power during these tests. While this process is
appropriate for the FTP, the SET is 2400 seconds long and the extended
operation at some high speed and load points can lead to some hybrid
systems not being able to sustain peak power over the course of the
test due to thermal limitations on the motor generator (generally due
to material limitations) and limitations on the battery storage
capacity and available usable energy. Under these scenarios, the hybrid
system will typically derate the motor generator to thermally protect
it, resulting in a sustained peak power that is lower than that
determined using the GTR No. 4 process.
Under the final test procedure, the powertrain system rated power
determination in 40 CFR 1036.527 includes the determination of both
peak and continuous rated power. The peak rated power
(P<INF>rated</INF>) is used in the transient FTP test procedure, while
the continuous rated power (P<INF>contrated</INF>) is used in the
steady-state SET test procedure. The vehicle C speed, v<INF>refC</INF>,
is also determined as a result of this process. This is the maximum
vehicle speed at which Psys equals Pcontrated.
The final compression-ignition vFTP duty cycle vehicle speed
profile was derived from the compression-ignition FTP vehicle duty-
cycle developed in SAE 2012-01-0878. In this work, a vehicle FTP cycle
and a vehicle SET cycle were created based on the transient diesel
engine FTP and engine SET duty cycles. The vehicle cycles are the same
duration and have similar power requirements and performance when
compared to the engine cycles. The alignment of the engine and vehicle
cycles maintain a consistency within vehicle and engine emissions
evaluations. The compression-ignition FTP vehicle speed profile is not
applicable to the spark-ignition FTP vehicle speed profile due to
differences in the engine duty-cycle lengths, speed profiles, and
torque profiles. Thus, a separate vehicle speed profile had to be
developed for the spark-ignition FTP duty cycle. Using the methodology
in SAE 2012-01-0878, a vehicle speed profile was developed for the
spark-ignition FTP duty cycle and a comparison between the two cycles
can be found in Table II-2. The vehicle speed profiles can be found in
Figure II-1 and Figure II-2.
Table II-2--Comparison Between FTP Vehicle Duty-Cycle Metrics for
Vehicles with Compression-Ignition and Spark-Ignition Engines
------------------------------------------------------------------------
Compression- Spark-ignition
Cycle metric ignition FTP FTP vehicle duty
vehicle duty cycle cycle
------------------------------------------------------------------------
Maximum acceleration (m/s2)..... 1.55 1.47
Maximum deceleration (m/s2)..... -2.26 -2.15
Average speed (mph)............. 20.1 19.2
Maximum speed (mph)............. 60.6 60.8
Stop duration (%)............... 3.3 4.7
Distance (miles)................ 6.4 6.4
------------------------------------------------------------------------
BILLING CODE 6560-50-P
[[Page 34323]]
[GRAPHIC] [TIFF OMITTED] TR29JN21.003
The road gradient profile is designed to further align the
powertrain system load for engines installed in conventional vehicles
and hybrid systems to eliminate the deviations in cumulative work done
between the engine and powertrain test. The grade profiles were
developed to align the power versus time and cycle work of the vehicle
profiles (compression-ignition vFTP, spark-ignition vFTP, and vSET) to
the compression-ignition and spark-ignition FTPs, and SET. The general
process was based on the development of the grade profile for the World
Harmonized Vehicle Cycle (WHVC).\15\ A reference normalized power curve
was generated using denormalized torque and speed curves from 50
different compression-ignition engines with multiple engine ratings for
the compression-ignition FTP, and SET. The denormalized curves were
normalized individually for each engine based on the engine's rated
power. The normalized power curves were then averaged to define the
final reference normalized power curve. Ten different spark-ignition
engine torque curves were used for the spark-ignition FTP. The duty-
cycle velocity profile over time was then divided into multiple mini-
cycles. Within each mini-cycle, a constant grade was defined in such a
way that the energy calculated from the normalized power curve was
matched for a given engine power rating. Power ratings between 100 and
500 kW were used to develop the compression-ignition vFTP, spark-
ignition vFTP, and vSET duty-cycles. The average slope was calculated
from the road grade profiles generated for the power ratings between
100 and 500 kW. The average fixed slope was calculated for every time
step along the drive cycle, and a second order polynomial was chosen
for the FTP duty-cycles to describe correlation between, and account
for the differences in, the average fixed and individual slopes based
on the rated power (Prated) of the powertrain. The equation and
coefficient descriptions follow:
---------------------------------------------------------------------------
\15\ Six, C., Siberholz, G., Fredriksson, J., Geringer, B.,
Hausberger, S. Development of an exhaust emission and CO2
measurement test procedure for heavy-duty hybrids (HDH). October 27,
2014. Available online at: <a href="https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2">https://wiki.unece.org/download/attachments/4064802/20141027_ACEA_Report.pdf?api=v2</a>.
[GRAPHIC] [TIFF OMITTED] TR29JN21.004
Where a is error compensation in %/kW\2\, b is error compensation
in %/kW, and c is the average fixed slope pattern. Negative road grade
is included in the profile to ensured that a representative amount of
recuperation energy is provided by the test cycle for hybrid
applications. This enables accurate cycle power/work alignment for all
vehicles with the FTP duty cycles for both compression-ignition and
spark-ignition engines. Example vehicle road
[[Page 34324]]
grade profiles for a 350 kW compression-ignition and 400 kW spark-
ignition engine can be found in Figure II-3 and Figure II-4.
BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TR29JN21.005
[[Page 34325]]
During additional review of the development of the road grade
profile for vSET included in the proposal, it became apparent that the
powertrain might not be able to achieve the default vehicle C speed of
75.0 mph. To provide a representative maximum vehicle speed and vehicle
A and B speeds that are scaled to the C speed in the final test
procedure, the determination of vehicle C speed was added as an
additional revision to 40 CFR 1036.527. This maximum achievable vehicle
speed is used as the vehicle C speed in Table 1 of Sec. 1036.505 and A
and B speed are calculated as described in 40 CFR 1036.505. The final
test procedure replaces the proposed maximum vehicle C speed and the
default vehicle A and B speeds in the proposed additions to Table 1 of
Sec. 1036.505 with these calculated speeds. Adding the allowance to
scale the vSET test speeds based on the vehicle maximum achievable
speed required an accounting of the effect of these lower speeds on the
road grade determination. This resulted in an expansion of the proposed
second order polynomial equation for the vFTP to include vehicle speed
in the final test procedure. The expanded equation and coefficient
descriptions follow:
[GRAPHIC] [TIFF OMITTED] TR29JN21.006
Where a is error compensation in %/kW3, b is error compensation in
%/kW2[middot]mi/hr, c is error compensation in %/kW2, d is error
compensation in %/(mi/hr)2, e is error compensation in %/kW[middot]mi/
hr, f is error compensation in %/kW, g is error compensation in %/mi/
hr, and h is the average fixed slope pattern. Negative road grade is
included in the profile to ensure that a representative amount of
recuperation energy is provided by the test cycle for hybrid
applications. This enables accurate cycle power/work alignment for all
vehicles with the engine SET duty-cycle.
The final test procedure also includes updates to the road grade
coefficients for the compression-ignition and spark-ignition vFTP duty
cycles from those proposed. EPA further reviewed the GTR No. 4 process
and noted that the work in mini cycles number 4 and 6 was set to zero.
This was a policy decision made during the GTR No. 4 process but is not
appropriate for the generation of EPA's duty-cycles, which should
include the actual work for these two mini cycles. While this
improvement results in only a marginal difference from that proposed,
it provides a more aligned comparison of work between the engine and
vehicle duty-cycles. The result of this was included in the final test
procedure in updated coefficients for the compression-ignition vFTP,
spark-ignition vFTP, and vSET duty cycles (vSET improvements are in
addition to the road grade coefficient updates already discussed).
Figure II-5 and Figure II-6 show a comparison of the effect on work
matching from changing the mini cycle work in mini cycles number 4 and
6 from zero to the actual work for a 300 kW engine. Note, this final
test procedure is limited to hybrid powertrains to avoid having two
different testing pathways for non-hybrid engines for the same
standards.
[[Page 34326]]
[GRAPHIC] [TIFF OMITTED] TR29JN21.007
BILLING CODE 6560-50-C
b. Hybrid Test Procedures for Vehicle Standards
i. Hybrid Fuel Maps
We are finalizing an option, after consideration of comments
received, to generate fuel maps for engine hybrids using the powertrain
test procedure in 40 CFR 1037.550. This was done by updating the hybrid
engine test procedures finalized in 40 CFR 1036.503, 1036.505,
1036.527, and 1037.550 and include the addition of a transmission model
to GEM and options in GEM to test without the transmission present,
using the model in its place.
ii. Mild Hybrid Certification
Under the Phase 2 regulations, manufacturers must conduct
powertrain testing if they wish to take credit for hybrid systems,
including mild hybrid systems. However, manufacturers have expressed
concerns about the cost of powertrain testing and that the existing
procedure may not measure improvements from certain mild hybrid
systems. EPA requested comment on alternative means of evaluating mild
hybrids noting that manufacturers have asked EPA to consider the
following options:
[[Page 34327]]
<bullet> Allow manufacturers to test a powertrain and apply
analytically derived scaling factors to others (e.g., scale by fraction
of battery capacity or motor capacity) under 40 CFR 1037.235(h).
<bullet> Allow manufacturers to use international test procedures
for battery capacity, motor power, and motor efficiency.
<bullet> Provide smaller credit (potentially with a volume limit
and/or only for limited time) in exchange for less testing (e.g.,
reduced benefit when using the simplified model spreadsheet that is
available under docket no. EPA-HQ-OAR-2014-0827-2109).
Commenters generally responded with support for EPA addressing mild
hybrid certification but did not provide any concrete means to address
concerns surrounding the cost of powertrain testing. In addition,
commenters stated that the existing procedures in the proposal may not
measure improvements from certain mild hybrid systems. This section
presents the changes we are adopting to hybrid test procedures after
consideration of comments received. Additional details on these and
other hybrid test procedure amendments or clarifications requested by
commenters and our responses are available in Chapter 2 of our Response
to Comments.
After further consideration, including the lack of additional input
on these mild-hybrid certification options, we have concluded that the
engine hybrid test procedure proposed in this rule, is the best pathway
for these hybrids. This will allow a manufacturer to test a mild hybrid
engine without having to certify the hybrid with a transmission under
the powertrain testing option. Finalizing these changes allows the test
results to better reflect the performance of mild hybrid's that are not
integrated into the transmission, without requiring that the
transmission be part of the certified configuration. Finalizing this
procedure also allows the test results to be used for additional
appropriate vehicles, since the test results will not be limited to the
transmission that was included during the test, as is required for non-
hybrid powertrains utilizing 40 CFR 1037.550. This mild hybrid engine
test procedure was finalize via additions to the hybrid powertrain test
procedure revisions in 40 CFR 1036.503, 1036.505, 1036.510, 1036.527,
and 1037.550 and includes the addition of a transmission model to GEM
and options in GEM to test without the transmission present, using the
model in its place.
B. Heavy-Duty Engine GHG Emission Standards and Flexibility
1. Revisions to Credit Provisions for Vocational Engine Emissions
Standards
EPA proposed several updates to the credit provisions related to
credit provisions for vocational engines and requested comment on these
credit provisions (see 85 FR 28145). This section presents the changes
we are adopting to vocational engine credit provisions after
consideration of comment received. Additional details on comment on
these credit provisions and our response are available in Chapter 2.4
of our Response to Comments.
In developing the baseline emission rates for vocational engines in
the final Phase 2 rulemaking, we considered MY 2016 FTP certification
data for diesel engines, which showed an unexpected step-change
improvement in engine fuel consumption and CO<INF>2</INF> emissions
compared to data considered in the proposed rule. The proposed baseline
emission rates came from the Phase 1 standards, which in turn were
derived from our estimates of emission rates for 2010 engines. The
underlying reasons for this shift in the 2016 Phase 2 final rule were
mostly related to manufacturers optimizing their selective catalytic
reduction (SCR) thermal management strategy over the FTP in ways that
we (mistakenly) thought they already had in MY 2010 (i.e., the Phase 1
baseline).
As background, the FTP includes a cold-start, a hot-start and
significant time spent at engine idle. During these portions of the
FTP, the NO<INF>X</INF> SCR system can cool down and lose
NO<INF>X</INF> reducing efficiency. To maintain SCR temperature,
manufacturers initially used a simplistic strategy of burning extra
fuel to heat the exhaust system. However, during the development of
Phase 1, EPA believed manufacturers were using more sophisticated and
efficient strategies to maintain SCR temperature. EPA's
misunderstanding of the baseline technology for Phase 1 provided engine
manufacturers the opportunity to generate windfall credits against the
FTP standards.
For the Phase 2 final rule, EPA revised the baseline emission rate
for vocational engines to reflect the actual certified emission levels.
The Phase 2 vocational engine final CO<INF>2</INF> baseline emissions
are shown in the table below. More detailed analyses on these Phase 2
baseline values of tractor and vocational vehicles can be found in
Chapter 2.7.4 of the Phase 2 Final RIA.\16\
---------------------------------------------------------------------------
\16\ U.S. EPA, U.S. DOT/NHTSA. Greenhouse Gas Emissions and Fuel
Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles
-Phase 2: Regulatory Impact Analysis, August 2016, EPA-420-R-16-900.
See p. 2-76.
Table II-3--Phase 2 Vocational Engine CO2 and Fuel Consumption Baseline
Emissions
------------------------------------------------------------------------
Units HHD MHD LHD
------------------------------------------------------------------------
g/bhp-hr..................................... 525 558 576
gal/100 bhp-hr............................... 5.1572 5.4813 5.6582
------------------------------------------------------------------------
EPA did not allow the carryover of Phase 1 vocational engine
credits into the Phase 2 program, consistent with these adjustments to
the baselines. Since this issue does not apply for RMC emissions, the
restriction was applied only for engines certified exclusively to the
FTP standards (rather than both FTP and RMC standards). We believed
that allowing engine credits generated against the Phase 1 diesel FTP
standards to be carried over into the Phase 2 program would have
inappropriately diluted the Phase 2 engine program. However, this was
in the context of unadjusted credits.
After further consideration, we now believe that it would not
dilute the program if the credits were appropriately adjusted to more
accurately reflect improvement over the true baseline levels.
Allowing the portion of the credits that represent actual emission
improvements to be carried forward is consistent with our rationale
from Phase 2. Thus, we are allowing in Sec. 1036.701(j), for the
purpose of carrying Phase 1 credits into the Phase 2 program, and not
compliance with Phase 1 standards, that manufacturers may recalculate
the credits in their initial Phase 1 averaging, banking, and trading
(ABT) vocational engine averaging set relative to the Phase 2 baseline
engine values. The recalculated vocational engine credits for an ABT
averaging set will be allowed into the Phase 2 engine program to the
same extent as tractor engine credits. Cummins submitted a late comment
(see Docket ID EPA-HQ-OAR-2019-0307-0066) requesting clarification of
whether manufacturers would have the option of applying these
vocational carryover provisions to one ABT averaging set but not
another (i.e., that EPA would not require the recalculation of all
averaging sets.) This final rule affirms that recalculation of
vocational credits is to be applied to all engines within an individual
ABT averaging set and that
[[Page 34328]]
other averaging sets, such as tractors, are not affected by these
vocational carryover provisions. EMA commented that manufacturers
should be able to opt in to recalculating credits on an engine family
by engine family basis, as applying this adjustment to all engine
families could affect existing Phase 1 compliance for engines above the
Phase 2 baseline value. However, EPA is only allowing this
recalculation for the purpose of determining the amount of credit that
can be carried into the Phase 2 program, and adjusting the credits for
all the engine families a manufacturer chose to include in their
initial ABT averaging set for Phase 1 program properly accounts for the
net credits that can be carried forward. In the ABT program, all engine
families within an averaging set are used in the calculation of
credits, and manufacturers cannot pick and choose which engine families
are used in that calculation.
As noted in the Phase 2 final rule, allowing additional flexibility
for compliance with engine standards does not cause any increase in
emissions because the manufacturers must still comply with the vehicle
standards (See 81 FR 73499, October 25, 2016). However, this
flexibility could allow some manufacturers to find a less expensive
compliance path.
2. Special Flexibility for Vocational Engines and Credits
EPA requested comment on several updates to the special flexibility
provisions for vocational engines (see 85 FR 28145). This section
presents the regulatory changes we are adopting after consideration of
comments received. Additional details on comments received on these
provisions and our responses are available in Chapter 2.4 of our
Response to Comments.
In the existing regulations at 40 CFR 1036.150(p), EPA provided
special flexibility for engine manufacturers that certify all their
model year 2020 engines within an averaging set to the model year 2021
FTP and SET standards and requirements. Where 40 CFR 1036.150(p)
applies, paragraph (p)(1) specifies that GHG emission credits that
manufacturers generate with model year 2018 through 2024 engines may be
used through model year 2030, instead of being limited to a five-year
credit life as specified in 40 CFR 1036.740(d). Note that under the
Phase 2 final rule this provision in effect only applies to
manufacturers of tractor engines, as under 40 CFR 1036.701(j) EPA did
not allow the carryover of Phase 1 vocational engine credits into the
Phase 2 program (81 FR 73499, October 25, 2016). Where 40 CFR
1036.150(p) applies, paragraph (p)(2) specifies that manufacturers are
also allowed to certify model year 2024 through 2026 tractor engines to
alternative standards that are slightly higher than the otherwise
applicable standards. Note that in the table of alternative standards
in the Phase 2 final rule EPA included values for medium and heavy
heavy-duty vocational engines, but these values are identical to the
Phase 2 standards and not slightly higher due to our concerns about
windfall credits if carryover of Phase 1 credits were allowed.
The applicability of 40 CFR 1036.150(p) is based on the choices
manufacturers made when certifying their MY 2020 engines. Instead of
certifying engines to the final year of the Phase 1 engine standards,
manufacturers electing the alternative instead certified to the MY 2021
Phase 2 engine standards. Because these engine manufacturers reduced
emissions of engines that would otherwise have been subject to the more
lenient MY 2020 Phase 1 engine standards, there can be a net benefit to
the environment. These engines do not generate credits relative to the
Phase 1 standards but instead generate credits relative to the pulled
ahead MY 2021 Phase 2 engine standards. Because the vehicle standards
themselves are unaffected, the alternative MY 2024-2026 engine
standards will not dilute or diminish the overall GHG reductions or
fuel savings of the program. Vehicle manufacturers using engines
subject to the alternative MY 2024-2026 standards would need to adopt
additional vehicle technology (i.e., technology beyond that projected
to be needed to meet the engine standards) to meet the applicable
vehicle GHG standards. The result is that the vehicles would still
achieve the same GHG emissions in use.
The proposed rule included an amendment to address the concern
regarding Phase 1 windfall credits and requested comment on the
possibility of a similar set of alternative standards for vocational
engines. CARB and Volvo commented that they support these changes and
flexibilities. Cummins commented opposing both the alternative MY 2024
through 2026 vocational engine standards and extending the life of
credits generated from early compliance with Phase 2 vocational
standards. The American Council for an Energy-Efficient Economy
commented opposing extending the life of vocational engine credits
generated in Phase 1, stating that doing so does not result in emission
reductions but would increase emissions and reduce the rule's overall
stringency. Cummins also commented that manufacturers had already
developed and certified MY 2020 products without consideration of these
changes, and even if post hoc recertification was possible, allowing
them now would potentially be an advantage or disadvantage to
individual manufacturers.
As discussed in section II.B.1, we are finalizing provisions on
calculating credits relative to a baseline that addresses these
windfall credit concerns, which also results in the extended credit
life flexibility under 40 CFR 1036.150(p)(1) now being available to
vocational vehicles that qualify under 40 CFR 1036.150(p). We are also
finalizing a set of alternative standards for vocational engines, as
shown in Table II-4.
Table II-4--Alternative Standards for Vocational Engines
------------------------------------------------------------------------
Medium Heavy heavy-
heavy-duty duty
Model years vocational vocational
(g/hp-hr) (g/hp-hr)
------------------------------------------------------------------------
2024-2026................................... 542 510
------------------------------------------------------------------------
The Phase 2 standards are implemented in three MY steps: 2021,
2024, and 2027. The largest step change in stringency occurs in MY
2024, where approximately two-thirds of the total numeric reduction in
the MY 2021 through MY 2027 standards is achieved, with the remaining
one-third occurring in MY 2027. For the alternative tractor engine
standards, EPA reversed the magnitude of the MY 2024 and MY 2027 step
changes, where the MY 2024 alternative standard represents one-third of
the total numeric reduction and is slightly higher than the Phase 2
standard. The standards at the beginning (MY 2021) and ending (MY 2027)
steps of the Phase 2 program remain the same in either case, and only
the level of decrease in standard for MY 2024 changes with the
alternative standards. EPA determined the alternative standards for
vocational engines by adjusting the magnitude of the MY 2024 standard
in the same manner as used to determine the alternative tractor engine
standards in the Phase 2. The Phase 2 vocational engine standards
decrease by 10 g/hp-hr between MY 2021 and MY 2027, with a 7 g/hp-hr
step change in the MY 2024 standard (approximately two-thirds of the
total numeric reduction) and a 3 g/hp-hr step change in MY 2027. For
the alternative vocational engine standards in MY 2024-2026, we are
adopting a 3 g/hp-hr reduction from the MY 2021 standard (from 545 to
542 g/hp-hr for
[[Page 34329]]
medium heavy-duty (MHD) and 513 to 510 g/hp-hr for heavy heavy-duty)
instead of 7 g/hp-hr. EPA believes that allowing these slightly higher
(approximately 0.7 to 0.8% compared to the Phase 2 final rule) engine
standards for vocational vehicles is justified, as the overall vehicle
standards will still be met. Engine development and vehicle technology
choices are pathways to meeting overall vehicle standards, as is the
use of credits generated by early compliance. EPA's alternative engine
standards provisions for vocational vehicles for MYs 2024-2026 allows
manufacturers flexibility to choose the mix of engine and vehicle
technologies that will comply with the standards. As noted in the Phase
2 final rule and this rule's proposal, EPA views this type of
alternative as being positive from the environmental and energy
conservation perspectives, as vehicle-level emission standards remain
the same, but manufacturers are provided with significant flexibility
on engine emission standards and credit life provisions that may reduce
their compliance costs.
Regarding the adverse comments received, including whether or not
manufacturers had the opportunity to consider these changes prior to MY
2020, these changes correspond to the corrected approach to Phase 1
credit calculations explained in Section II.B.1 above. At the time of
the Phase 2 final rule, we believed that allowing Phase 1 vocational
engine credits, without adjustment, to be carried over to the Phase 2
program would result in ``windfall'' credits, or dilution of the
benefits of the Phase 2 program, and we adopted restrictions to limit
their use. However, after the Phase 2 final rule we recognized that an
alternative to restricting Phase 1 vocational engine credits because of
windfall concerns would be to adjust credits earned in Phase 1
downward, relative to a baseline of the lower Phase 2 emissions
standards, and in doing so, we would be extending to vocational engine
manufactures the same flexibilities that were provided to tractor
engine manufacturers. In this final rule we are allowing the vocational
engine credits generated in Phase 1 to be adjusted downward and used in
Phase 2 program through MY 2030, just as they were for tractors. In
setting lower baseline emission values for Phase 1 vocational engine
credits and providing the corresponding program flexibilities, EPA does
not intend to advantage or disadvantage any manufacturer. Rather, we
are removing restrictions that were applied only to vocational engines
but no longer should be applied now that we are finalizing provisions
that provide a proper accounting of the emission improvements realized
by manufacturers who chose to certify their MY 2020 engines to the MY
2021 Phase 2 standards, so vocational and tractor engines are treated
the same. In addition, the revised MY 2024-2026 alternative standards
for vocational engines, while slightly higher than those in the Phase 2
final rule by 0.7 to 0.8%, do not reduce the overall stringency of the
Phase 2 program, but instead reflect the alternative standards we would
have adopted in the Phase 2 final rule alongside the similar tractor
provisions, and for the same reasons we finalized those tractor
provisions, had we considered adjusting baseline emission rates used
for calculating Phase 1 credits. Manufacturers that qualify to use the
alternative MYs 2024-2026 engine standards accelerated their compliance
with the more stringent MY 2021 Phase 2 standards by one model year. As
we explained in the Phase 2 final rule, because the vehicle standards
themselves are unaffected, these alternative engine standards will not
dilute or diminish the overall GHG reductions or fuel savings of the
program. Vehicle manufacturers using engines subject to the alternative
MYs 2024-2026 standards will need to adopt additional vehicle
technology (i.e., technology beyond that projected to be needed to meet
the engine standard) to meet the applicable vehicle GHG standards. The
result is that the vehicles using engines that comply with the
alternative standards will still achieve the same overall GHG emissions
in use. EPA believes that these alternative standards are appropriate,
and allowing alternative engine standards for vocational vehicles that
qualify is justified, for these reasons, and that vocational engine
manufacturers who met the Phase 2 engine standards one year in advance
of the MY 2021 implementation date should have the same flexibility as
tractors to earn and use those credits through MY 2030.
3. Confirmatory Testing of Engines and Measurement Variability
EPA proposed updates to the procedure for confirmatory testing of
the fuel mapping test procedure related to providing an interim 2%
allowance during confirmatory testing of the fuel mapping test
procedure finalized in the Phase 2 final rule and requested comment on
``. . . whether it appropriately balances the impacts of testing
variability for fuel maps'' (see 85 FR 28146, May 12, 2020). This
section presents the changes we are adopting to the confirmatory
testing portion of the fuel mapping test procedure after consideration
of comments received. Additional details on these comments and our
responses are available in Chapter 2 of our Response to Comments.
During the Phase 2 rulemaking, manufacturers raised concern about
measurement variability impacting the stringency of the engine GHG
standards and fuel map requirements. As noted in the Phase 2 final
rule, the final standards were developed to account for this. (81 FR
73571, October 25, 2016). Manufacturers raised particular concern about
variability of fuel map measurements because neither they nor EPA had
sufficient experience measuring fuel maps (in a regulatory context) to
fully understand the potential impacts of measurement variability. We
estimated the fuel map uncertainty to be equivalent to the uncertainty
associated with measuring CO<INF>2</INF> emissions and fuel consumption
over the FTP and SET cycles, which we estimated to be about one
percent. However, the Phase 2 final rule noted that we were
incorporating test procedure improvements that would further reduce
test result uncertainty. We also noted that ``[i]f we determine in the
future . . . that the +1.0 percent we factored into our stringency
analysis was inappropriately low or high, we will promulgate technical
amendments to the regulations to address any inappropriate impact this
+1.0 percent had on the stringency of the engine and vehicle
standards.'' (81 FR 73571, October 25, 2016)
In conjunction with this intention, EPA has worked with engine
manufacturers to better understand the variability of measuring fuel
maps using the test procedures and cycles specified by EPA in the Phase
2 final rule. Through that work, we identified several sources of
variability that can be reduced by making small changes to the test
procedures. EPA is adopting these changes, as explained in Sections
II.A.1 through II.A.3 of this final rule.
SwRI performed emission measurements in multiple test cells and
identified distributions of error for other test inputs such as
measured fuel properties and calibration gas concentrations. SwRI then
used a Monte Carlo simulation to estimate a distribution of errors in
measured fuel maps.\17\ After reviewing the results, EPA had several
significant observations which we discussed in the proposal for
[[Page 34330]]
this final rule and which EPA confirms in this final action:
---------------------------------------------------------------------------
\17\ Sharp, Christopher A., et al., ``Measurement Variability
Assessment of the GHG Phase 2 Fuel Mapping Procedure'', Southwest
Research Institute, Final Report, December 2019.
---------------------------------------------------------------------------
1. The variability of measuring CO<INF>2</INF> and fuel consumption
during fuel mapping is greater than the one percent assumed in the
Phase 2 final rule. Variability from vehicles without idle test cycles
is <1.8% (1.68 to 1.8%), while variability from vehicles with idle test
cycles is <2.8% (2.0 to 2.79%).
2. The variability of measuring CO<INF>2</INF> and fuel consumption
during the fuel mapping procedure is roughly the same as that of the
FTP and SET cycles, 3.34% for the FTP and 1.99% for the SET.
3. Measuring CO<INF>2</INF> and fuel consumption at idle is
particularly challenging.
4. The data obtained during the test program at SwRI did not
include all the test procedure changes being adopted in 40 CFR parts
1036 and 1037 that will further reduce fuel mapping test variability
and therefore the variability is likely to be lower than reported by
the SwRI.
Manufacturers have indicated they are concerned about the
possibility of EPA changing an official fuel map result as a
consequence of EPA confirmatory testing where the measured maps were
within an expected range of variability. In the context of the SwRI
test program, EPA observed similarity between the range of variability
of measuring fuel maps and the range of variability of measuring
CO<INF>2</INF> and fuel consumption over the FTP and SET cycles
(measurements for which EPA has already determined in both Phase 1 and
Phase 2 that no such allowances are needed). These results indicate
that there is no additional source of increased variability associated
with the fuel mapping test procedure and suggest that manufacturers
should be able to comply without any special provisions. Additionally,
the data we have available indicates that the manufacturers may
potentially over time be able to take advantage of the 2% allowance,
resulting in a reduction in stringency of the standards. We anticipate
that this would not happen over the next few model years, as
manufacturers will need time to implement the revised test procedures
adopted in this rule that will reduce the variability of the fuel map
test procedure to levels at or below the variability of the FTP and SET
test procedures.
After considering the comments received, we are adopting the
limited transitional approach aimed at addressing the manufacturers'
variability concerns. As manufacturers implement this rule's revised
test procedures to reduce variability, we will analyze and compare a
manufacturer's declared and measured fuel maps to those that result
from our confirmatory testing, with the goal of ensuring the long-term
integrity of the Phase 2 program. We are codifying the interim
provision for model years 2021 and later in 40 CFR 1036.150, under
which EPA will not replace a manufacturer's fuel maps during
confirmatory testing if the difference between the EPA-measured fuel
maps and the manufacturer's declared maps is less than or equal to 2.0
percent. We may revisit the interim 2% allowance in a future
rulemaking.
EPA also intends to further review data and developments in this
area. We intend to review this provision as we learn more about the
impact of measurement variability on measured and declared fuel maps
submitted during the certification process for future model years
(including the full impact of the test procedure improvements that are
intended to reduce measurement variability), which may inform whether
we determine additional action is warranted in the future with respect
to fuel mapping variability. We also intend to enter into a round robin
study of criteria and GHG pollutant engine testing variability with
interested engine manufacturers, with the involvement of the Truck and
Engine Manufacturer's Emission Measurement and Testing Committee. This
data will add to the existing knowledge regarding the variability of
the FTP, SET and fuel mapping test procedures and may help inform if
future action is needed to further improve the test procedures.
We are also finalizing an algorithm for comparing fuel maps.
Because fuel maps are multi-point surfaces instead of single values, it
would be a common occurrence that some of EPA's points would be higher
than the manufacturer's while others would be lower. This algorithm was
inadvertently proposed as an interim provision in 40 CFR 1036.150(q)
along with the 2.0 percent variability allowance. The algorithm and
fuel map comparison process during a confirmatory test is needed for
confirmatory testing regardless of an allowance. Therefore, in this
final rule the algorithm and all supporting text are located at 40 CFR
1036.235(c)(5). The limited interim 2.0 percent variability allowance
is located at 40 CFR 1036.150(q).
EPA's measured fuel maps will be used with GEM according to 40 CFR
1036.540 to generate emission duty cycles which simulate several
different vehicle configurations, generating emission results for each
of the vehicles for each of the duty cycles. Each individual duty cycle
result will be weighted using the appropriate vehicle category
weighting factors in Table 1 of 40 CFR 1037.510 to determine a
composite CO<INF>2</INF> emission value for that vehicle configuration.
Note that the equation is being finalized to use values before rounding
as this is consistent with the provisions in 40 CFR 1065.20 to not
round intermediate values. When the process is repeated for the
manufacturer's fuel maps, the average percent difference between fuel
maps will be calculated as:
[GRAPHIC] [TIFF OMITTED] TR29JN21.008
Where:
i = an indexing variable that represents one individual weighted
duty cycle result for a vehicle configuration.
N = total number of vehicle configurations.
e<INF>CO2compEPA</INF>i = unrounded composite mass of CO<INF>2</INF>
emissions in g/ton-mile for the EPA confirmatory test.
e<INF>CO2compManu</INF> = unrounded composite mass of CO<INF>2</INF>
emissions in g/ton-mile for the manufacturer declared map.
4. Other Minor Heavy-Duty Engine Amendments
EPA proposed three additional updates to the testing and
measurement provisions of 40 CFR part 1036, related to measuring
emissions from heavy-duty
[[Page 34331]]
engines and requested comment on general improvements to the engine
test procedures and compliance provisions (see 85 FR 28147). This
section presents these three additional changes we are adopting to
engine test procedures. Additional details on these and other engine
testing and measurement amendments or clarifications requested by
commenters and our responses are available in Chapter 2 of the Response
to Comments.
<bullet> Correcting the assigned N2O deterioration factor in Sec.
1036.150(g). In the Phase 2 proposed rule, EPA proposed to lower the
N<INF>2</INF>O standard from 0.10 g/hp-hr to 0.05 g/hp-hr for model
year 2021 and later diesel engines. In that context, we also proposed
to lower the assigned deterioration factor (DF) from 0.020 g/hp-hr to
0.010 g/hp-hr for model year 2021 and later diesel engines. EPA
explained in the preamble to the Phase 2 final rule that we were not
finalizing the change to the standard (81 FR 73530, October 25, 2016),
but inadvertently finalized the proposed DF change in the regulations.
We proposed in this rulemaking to correct this error, consistent with
EPA's clear statement in the Phase 2 final rule that we were not
finalizing the change to the standard. However, given that finalizing
the assigned DF of 0.01 g/hp-hr for N<INF>2</INF>O in the regulations
was an oversight on EPA's part in the Phase 2 final rule and that the
Phase 2 final rule was inadvertently internally inconsistent, and after
consideration of EMA's comment that manufacturers will not have time to
correct or account for a change in the assigned DF in time for their MY
2021 certifications, we are deferring changing the assigned DF to 0.02
g/hp-hr until MY 2022 within the revisions finalized in this
rulemaking.
<bullet> Clarifying a reference to non-gasoline engine families in
Sec. 1036.705(b)(5). The second sentence of Sec. 1036.705(b)(5) is
intended to refer to non-gasoline engine families. However, the
existing text is not clear. As written, it can be read to mean that
gasoline engine families may not generate emission credits. EPA is
adding ``non-gasoline'' to clarify the intended meaning.
<bullet> Engine families. We are revising Sec. 1036.230 to allow
engine families to be divided into subfamilies with respect to
CO<INF>2</INF>. This allowance simplifies the certification process
without changing the overall requirements.
<bullet> Adding a summary of previously applicable emission
standards as appendix A of part 1036. The new appendix is being
provided for reference purposes only regarding previously applicable
emission standards and will cover regulatory text being deleted from 40
CFR part 86.
Except as noted above, we received no adverse comments on these
proposed amendments and are adopting them without modification.
C. Heavy-Duty Vehicle GHG Emission Standards and Flexibility
1. Aerodynamic Compliance Provisions
In addition to the aerodynamic test procedure amendments described
in Section II.A.6, we proposed several updates to Sec. 1037.150(s) as
it relates to EPA's confirmatory testing of aerodynamic parameters and
Sec. 1037.305 as it relates to our selective enforcement audit (SEA)
procedures. We also requested comment on general improvements to the
aerodynamic compliance provisions (see 85 FR 28147). This section
presents the changes we are adopting to our confirmatory testing and
SEA procedures after consideration of comments received. Additional
details on these and other aerodynamic amendments or clarifications
requested by commenters and our responses are available in Chapter 2 of
our Response to Comments.
a. Confirmatory Testing for F<INF>alt-aero</INF>
As described in 40 CFR 1037.235(c), EPA may perform confirmatory
testing on a manufacturer's vehicles, including a vehicle tested to
establish the F<INF>alt-aero</INF> value. The regulations also include
an interim provision in Sec. 1037.150(s) that outlines how EPA may and
when EPA will not replace a manufacturer's F<INF>alt-aero</INF> value
based on confirmatory test results. This interim provision connects
EPA's confirmatory testing to the audit procedures of Sec. 1037.305.
In keeping with the principle that good engineering judgment \18\ would
generally call for more data rather than selecting a single value, and
after consideration of comment, EPA is finalizing our proposed
provision to require EPA to perform a minimum of 100 valid runs before
replacing a manufacturer's F<INF>alt-aero</INF> value in confirmatory
testing with some additional clarifications in Sec. 1037.150(s).
---------------------------------------------------------------------------
\18\ Good engineering judgment is defined in 40 CFR 1068.30 as
judgments made consistent with generally accepted scientific and
engineering principles and all available relevant information. See
40 CFR 1068.5 for requirements regarding applying good engineering
judgment.
---------------------------------------------------------------------------
CARB commented in support of increasing the number of runs from SEA
to 100 to limit false failures, but requested in comment to know the
origin of the proposed minimum 100 valid runs for confirmatory testing.
Our intent with the finalized requirement for 100 valid confirmatory
runs is to maintain consistency with the existing regulatory language
adopted in the Phase 2 final rulemaking for SEA testing. The existing
Sec. 1037.305(a)(7)(iii) states: ``The vehicle passes if you perform
100 coastdown runs and C<INF>d</INF>A<INF>wa-upper</INF> is greater
than and C<INF>d</INF>A<INF>wa-lower</INF> is lower than the upper
limit of the bin to which you certified the vehicle.'' Similarly, as
noted below in Section II.C.1.b, we are also finalizing our
corresponding proposed language in the audit procedures of Sec.
1037.305(a)(5) clarifying that manufacturers must perform a minimum of
24 runs to pass and a minimum of 100 runs to fail.
EMA requested additional modifications to Sec. 1037.150(s)
regarding EPA's approach to calculating a new F<INF>alt-aero</INF>
value in confirmatory testing. EMA suggested that the regulation more
explicitly connect to the SEA procedures for pass/fail criteria and the
coastdown procedures for calculating F<INF>alt-aero</INF>. They also
suggested we directly outline how EPA will replace a manufacturer's
F<INF>alt-aero</INF>. EMA suggested that EPA calculate two
F<INF>alt-aero</INF> values and apply the average of those values to
replace a manufacturer's value. We agree with EMA's suggestions to
clarify the connections to the SEA procedures of Sec. 1037.305 and the
coastdown test procedures of Sec. 1037.528 and we updated Sec.
1037.150(s) accordingly. While we generally agree that additional data
is preferable, we are not committing to calculating multiple
F<INF>alt-aero</INF> values, as requested by EMA, due to consideration
of potential resource constraints; however, we have revised the
regulatory language to allow for it. We also are not finalizing an
approach to calculate the final F<INF>alt-aero</INF> when there are
multiple values. Our revised Sec. 1037.150(s) states that EPA will
``will generate a replacement value of F<INF>alt-aero</INF> based on at
least one C<INF>d</INF>A value and corresponding effective yaw angle''.
Additionally, as noted in the proposal regarding Sec. 1037.150(s),
we recognize that test conditions for coastdown testing are an
important consideration. For our confirmatory testing, EPA intends to
minimize the differences between our test conditions and those of the
manufacturer and we proposed a note in Sec. 1037.150(s) stating our
intent to test at similar times of the year. EMA requested additional
regulatory language regarding our intent to test at the same location
as well as time of year. We are expanding our proposed note in Sec.
1037.150(s) to include our intent to test at both the same time of year
and the same location, subject to
[[Page 34332]]
certain considerations. More specifically, we emphasize that the note
in Sec. 1037.150(s) is not a commitment by the agency due to the
limited number of coastdown test facilities, the challenges of
scheduling time for testing, and our prerogative to choose an
alternative facility if we have concerns about the original test
location. Our revised language in Sec. 1037.150(s) states that we
intend to test ``at similar times of the year where possible and at the
same location where possible and when appropriate.''
b. Selective Enforcement Audits for Tractors
We proposed and received no adverse comments to three typographical
edits to our aerodynamic testing audit procedures for tractors in Sec.
1037.305. We are finalizing those three edits as proposed and
additional editorial edits as follows:
<bullet> Section 1037.305--Replaced reference to 40 CFR 1068.420
with the range ``40 CFR 1068.415 through 1068.425'' as proposed.
<bullet> Section 1037.305(a)--Rephrased ``whether or not a tractor
fails to meet'' to the more concise ``whether a tractor meets''.
<bullet> Section 1037.305(a)(2)--Corrected ``coastdown effective''
to ``coastdown effective yaw angle'' as proposed.
<bullet> Section 1037.305(a)(7)--Added a missing ``m2'' following
the bin value of 5.95 in the example as proposed. Editorial revisions
to remove passive voice.
In comment, EMA suggested additional revisions to Sec. 1037.305(a)
allowing manufacturers to apply good engineering judgment in their
selective enforcement audit (SEA) testing if a production vehicle could
not be configured to meet the trailer height specified in Sec.
1037.501(g)(1)(i). We accept that a future production vehicle may be
designed such that it cannot be configured to match a trailer that
meets our current definition of standard trailer. We are finalizing a
broader revision to address all such scenarios where a production
vehicle cannot be configured to match a trailer that meets our current
definition of standard trailer, including but not limited to height,
that will address EMA's specific concern with meeting the standard
trailer's height requirements. We are adding language to clarify that a
manufacturer may seek EPA approval to use an alternate or modified
vehicle configuration, consistent with good engineering judgment, if
EPA chooses to audit a production vehicle configuration that cannot
meet any of the standard trailer requirements specified in Sec.
1037.501(g)(1).
As noted in Section II.C.1.a, we proposed and are finalizing a
provision in Sec. 1037.150(s) to require EPA to perform a minimum of
100 valid runs before replacing a manufacturer's F<INF>alt-aero</INF>
value in confirmatory testing. Similarly, we are finalizing our
corresponding proposed language in the audit procedures of Sec.
1037.305(a)(5) clarifying that manufacturers must perform a minimum of
24 runs to pass and a minimum of 100 runs to fail. Finally, we received
no adverse comments and are finalizing the proposed regulatory language
in Sec. 1037.305(a)(7)(v) allowing manufacturers to continue testing
and to generate additional data that EPA may consider in our pass/fail
determinations.
2. Idle Reduction Technologies
EPA proposed several provisions related to idle reduction
technologies. This section presents the changes we are adopting after
consideration of the comments received. See Chapter 2 of our Response
to Comments for further details, including additional idle reduction
amendments or clarifications requested by commenters and our responses.
a. Extended-Idle Reduction for Tractors
The Phase 1 version of GEM gives credit for extended idle emission
reduction technologies that include a tamper-proof automatic engine
shutoff system (AESS), with few override provisions. Phase 2 GEM gives
credit for a wider variety of idle reduction strategies, recognizing
technologies that are available on the market today, such as auxiliary
power units (APUs), diesel fired heaters, and battery powered units.
For example, a tamper-proof AESS with a diesel APU would be credited
with a 4 percent reduction in emissions, while an adjustable AESS with
a diesel fired heater would be credited with a 2 percent reduction in
emissions (81 FR 73601, October 25, 2016).
Our proposal to revise Sec. 1037.520(j)(4) to include GEM input
values for combinations of these technologies received support from
CARB, EMA, and Volvo and we are finalizing our proposed combinations of
idle reduction technologies as shown in Table II-5. Adding these values
to GEM reduces the compliance burden for manufacturers who would
otherwise need to apply for off-cycle credits for these technology
combinations. The values of these technology benefits were determined
using the same methodology used in the Phase 2 final rule.
Table II-5--GEM Input Values for AES Systems
------------------------------------------------------------------------
GEM input values
------------------------
Technology Tamper-
Adjustable resistant
------------------------------------------------------------------------
Standard AES system............................ 1 4
With diesel APU................................ 3 4
With battery APU............................... 5 6
With automatic stop-start...................... 3 3
With fuel-operated heater (FOH)................ 2 3
With diesel APU and FOH........................ 4 5
With battery APU and FOH....................... 5 6
With stop-start and FOH........................ 4 5
------------------------------------------------------------------------
b. Idle Reduction Overrides
In 40 CFR 1037.660, we identify three idle reduction technologies
(i.e., automatic engine shutdown, neutral idle, and stop-start) and
specify how these systems must operate to qualify for GEM credit.
Included among those provisions are allowances for overriding these
systems where it may damage the engine or create a safety issue for the
vehicle occupants or service personnel. This section highlights the
some of the idle reduction override provisions we are adopting, either
as proposed or further revisions after consideration of comments
received.
i. Automatic Engine Shutdown (AES) Overrides
While we did not specifically propose or request comment on AES
overrides, New Flyer (a bus manufacturer) commented that the override
condition for AES systems during servicing in Sec. 1037.660(b)(1)(ii)
(cross-referenced under the existing regulations for vocational
vehicles in Sec. 1037.660(b)(2)(i)) could pose a safety risk to
maintenance personnel. They stated that maintenance personnel may not
have a diagnostic scan tool required to deactivate the system and some
maintenance may require longer than the current 60-minute limit before
reactivation. New Flyer suggested an ``open engine compartment'' would
be a more appropriate override condition.
After consideration of New Flyer's safety concern for vocational
vehicles, we are revising Sec. 1037.660(b)(2) to allow a vocational
vehicle's AES system to delay shutdown if necessary while servicing the
vehicle without the scan tool requirement and time limit. Our final
revision removes the cross-reference in Sec. 1037.660(b)(2)(i) to that
particular provision in Sec. 1037.660(b)(1) and replaces it with a new
provision in Sec. 1037.660(b)(2)(ii). Our new provision allows a delay
in shutdown for vocational vehicles if the engine compartment is open
and replaces the
[[Page 34333]]
regulatory text regarding unsafe cab temperatures in the current Sec.
1037.660(b)(2)(ii), which is redundant with the existing cross-
reference to paragraph (b)(1) in paragraph (b)(2)(i). For vocational
vehicles, we believe an open engine compartment sufficiently indicates
that a vocational vehicle is being serviced and automatic engine
shutdown would provide limited environmental benefit. We are not taking
final action to revise the tractor-specific provision of Sec.
1037.660(b)(1)(ii) to allow an open engine compartment as a condition
for AES override, since the environmental benefits of AES on tractors
occurs when these vehicles are parked for extended durations where an
open engine compartment may not be a sufficient deterrent for the
operator to circumvent the AES.\19\
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\19\ Tractor manufacturers have the option to request and we may
approve additional override criteria as needed to protect the engine
and vehicle from damage and to ensure safe vehicle operation, as
stated in Sec. 1037.660(b).
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We are finalizing editorial revisions to Sec. 1037.660(b) so the
paragraphs consistently begin with ``When''. Additionally, we reordered
the paragraphs of Sec. 1037.660(b)(1) to move the servicing provision
previously located at paragraph (b)(1)(ii) to paragraph (b)(1)(vi) such
that the vocational vehicle AES provisions can continue to reference
the range of relevant (b)(1) paragraphs in paragraph (b)(2)(i).
ii. Neutral Idle Overrides
EPA proposed and is finalizing a provision in Sec.
1037.660(b)(3)(ii) that would allow the neutral idle system to delay
shifting the transmission into neutral if the transmission is in
reverse gear (85 FR 28271, May 12, 2020). New Flyer requested an
additional override when the vehicles is on a road grade of 6.0 percent
or more to prevent the safety concern of vehicle rollback. EPA agrees
with this safety concern and is finalizing a provision in Sec.
1037.660(b)(3)(iii) to allow a delay in neutral idle when the vehicle
is on a grade greater than or equal to 6.0 percent. EMA requested
additional overrides for ``safety; thermal protection of the emissions
aftertreatment; and maintenance of aftertreatment temperature within a
range for adequate emissions control''. EPA is not adopting EMA's
suggested override conditions as we do not think that they would likely
be appropriate without more specific criteria. Manufacturers continue
to have the option to justify the need for additional overrides for
their individual systems and seek EPA approval through Sec.
1037.660(b).
iii. Stop-Start Overrides
We requested comment on a specific list of override conditions for
stop-start systems (85 FR 28151, May 12, 2020). CARB expressed concern
that additional overrides may compromise emissions and requested a
requirement that manufacturers bring their proposed overrides to EPA
for approval. We are not requiring a ``case-by-case'' approval process
for these overrides, as suggested by CARB, but we note that, in the
certification application provisions of Sec. 1037.205(b)(5),
manufacturers are required to include a description of their idle
reduction technology, including the override conditions of Sec.
1037.660. We believe this continues to be an appropriate level of
oversight for these idle technologies and their associated override
conditions.
EMA and New Flyer supported the inclusion of all override
conditions listed in the proposed rule for comment, but their comments
did not expand on the need for any of the individual conditions to be
adopted. Each commenter requested additional override conditions and
included the rationale for those requests. Our final revisions to Sec.
1037.660(b)(4) cross-reference the provisions for vocational vehicle
AES (paragraph (b)(2)) and neutral idle (paragraphs (b)(3)(ii) and
(iii)) such that the new open engine compartment, reverse gear, and
road grade provisions for those systems also apply for stop-start
systems. EPA considered the original list and the commenters'
additional suggested override conditions and we are adopting the
following additional override criteria specific to stop-start systems
to ensure safety and/or effective system operation as noted in Sec.
1037.660(b)(4):
<bullet> When the steering angle is at or near the limit of travel
to avoid steering wheel kickback during engine start.
<bullet> When a wheel speed sensor failure may prevent the anti-
lock braking system from detecting vehicle speed.
<bullet> When an automatic transmission is in ``park'' or in
``neutral'' with the parking brake engaged because the feature is
intended to be used during driving operation.
<bullet> When a component failure protection mode is active, such
as starter motor overheating, which may prevent the engine from
restarting.
<bullet> When a fault is active on a system component needed to
start the engine, which may prevent the engine from restarting.
<bullet> When the flow of diesel exhaust fluid is limited due to
freezing, because an engine-off condition may further delay thawing and
SCR operation.
It was not clear that the remaining override conditions suggested
by commenters or presented for comment in the proposed rule pose a
widespread concern for safety, vehicle operation, or serviceability, or
could not be easily overridden by the driver, and we are not adopting
those overrides in our final revisions. However, manufacturers continue
to have the option to seek EPA approval for these or additional
criteria they believe are needed to protect the engine and vehicle from
damage and to ensure safe vehicle operation (see Sec. 1037.660(b)).
3. Weight Reduction
EPA proposed minor revisions to the weight reduction provisions
(see 85 FR 28150). This section presents the changes we are adopting
after consideration of comments received. See Chapter 2 of our Response
to Comments for additional details on some of these amendments,
including other amendments or clarifications requested by commenters
and our responses.
The regulations in 40 CFR 1037.520 include tables to calculate
weight reduction values for using certain lightweight components. The
sum of the weight reductions is used as an input to GEM. As noted in
Section II.A.2, EPA proposed two changes to Table 8 of that section
allowing manufacturers to use the heavy heavy-duty (HHD) values for
medium heavy-duty (MHD) vehicles with three axles (i.e., 6x4 and 6x2
configurations) and adding a footnote to the table to clarify that the
weight reduction values apply per vehicle (instead of per component)
unless otherwise noted. We received no adverse comments to the proposed
updates to Table 8 and we are finalizing the two changes.
We received comment from EMA requesting ``a process for adding in
other weight-savings technologies''. As described in Sec.
1037.520(e)(5), this process is available in the existing off-cycle
provisions of Sec. 1037.610 and no further action is needed or being
finalized in this rule. EMA also requested clarification on the origin
of certain weight reduction values for tires and recommended use of a
``base'' value for comparison. We note that all the values in Table 6
through Table 8 of Sec. 1037.520 were developed through notice and
comment in the HD Greenhouse Gas Emissions Phase 1 and Phase 2
rulemakings based on information as described in the Regulatory Impact
Analysis for the rules. We did not propose changes to the weight
reduction tables and are not taking any final action at this time to
[[Page 34334]]
update values to refer to a base weight, but manufacturers continue to
have the ability to apply through our off-cycle process.
4. Self-Contained Air Conditioning Units
We proposed a revision to Sec. 1037.115(e) to clarify that it is
``intended to address air conditioning systems for which the primary
purpose is to cool the driver compartment (85 FR 28151). This would
generally include all complete pickups and vans, but not self-contained
air conditioning or refrigeration units on vocational vehicles.'' CARB
and New Flyer requested additional clarification on the phrase ``self-
contained''. After consideration of submitted comments, we are
finalizing a modified version of the proposed changes to Sec.
1037.115(e)(1) that incorporates some of the feedback from commenters.
We are maintaining the proposed statement that this provision is
intended for A/C systems that cool the driver compartment. We're
clarifying that it generally applies to ``cab-complete'' pickups and
vans (see definition at Sec. 86.1803-01) which is more appropriate for
heavy-duty than ``complete pickups and vans'' as proposed. We are
expanding the existing statement that the paragraph does not apply for
self-contained A/C or refrigeration units by adding the phrases ``used
to cool passengers'' and ``used to cool cargo''. Finally, we further
clarify that a self-contained system for purposes of this provision is
an ``enclosed unit with its own evaporator and condenser even if it
draws power from the engine.''
5. Manufacturer Testing of Production Vehicles
The regulations require tractor manufacturers to annually chassis
test five production vehicles over the GEM cycles to verify that
relative reductions simulated in GEM are being achieved in actual
production. See 40 CFR 1037.665. We do not expect absolute correlation
between GEM results and chassis testing. GEM makes many simplifying
assumptions that do not compromise its usefulness for certification but
do cause it to produce emission rates different from what would be
measured during a chassis dynamometer test. Given the limits of
correlation possible between GEM and chassis testing, we would not
expect such testing to accurately reflect whether a vehicle was
compliant with the GEM standards. Therefore, Sec. 1037.665 does not
apply compliance liability to such testing.
The regulation also allows manufacturers to request approval of
alternative testing ``that will provide equivalent or better
information.'' Manufacturers have asked us to clarify this allowance
and we proposed to revise Sec. 1037.665 to provide an example that the
EPA may allow manufacturers to provide CO<INF>2</INF> data from in-use
operation, and CO<INF>2</INF> data from manufacturer-run on-road
testing, as long as the data allows for reasonable year-to-year
comparisons and includes testing from non-prototype vehicles (85 FR
28148). We didn't receive any comments on the proposed changes to Sec.
1037.665, and we are finalizing changes to the regulation as proposed.
To qualify, the vehicles would need to be actual production vehicles
rather than custom-built prototype vehicles. Such vehicles could be
covered by testing or manufacturer owned exemptions but would need to
be produced on an assembly line or other normal production practices.
Manufacturers would also need to ensure test methods are sufficiently
similar from year to year to allow for a meaningful analysis of trends.
6. Vehicle Model Year Definition
For Phase 2 tractors and vocational vehicles, the vehicle's
regulatory model year is usually the calendar year corresponding to the
vehicle's date of manufacture. However, the Phase 2 regulations allow
the vehicle's model year to be designated as the year before the
calendar year corresponding to the vehicle's date of manufacture if the
engine's model year is from an earlier year. We are amending as
proposed the definition of model year in Sec. 1037.801 to allow
vehicle manufacturers to extend the period during which a vehicle's
certification is valid to account for this flexibility. This
clarification more explicitly explains how vehicle manufacturers
utilize this existing flexibility.
After promulgation of the Phase 2 final rule, it became apparent
that the Phase 2 vehicle model year definition does not allow starting
vehicle production before the start of the named year if the engine
model year also begins in the earlier year. For example, if a
manufacturer would start its 2024 engine model year in December 2023,
the definition would not allow vehicles produced in 2023 to be model
year 2024.
To address this issue, EPA is allowing the option for the vehicle's
model year to be designated as the year after the calendar year
corresponding to the vehicle's date of manufacture. This has the effect
of allowing manufacturers to meet standards earlier with aligned engine
and vehicle model years. Model years would still be constrained to
reflect annual (rather than multi-year) production periods and include
January 1 of the named year.
We did not receive comments on these proposed change to the
definition of model year for vehicles. We are accordingly adopting the
revised definition for model year in 40 CFR 1037.801 for tractors and
vocational vehicles with a date of manufacture on or after January 1,
2021, as proposed, except that the final rule includes additional text
to make explicit the requirement for the model year to be based on the
manufacturer's annual production period for new models. This is
consistent with the definition of model year for vehicles subject to
Phase 1 standards in the same section.
7. Compliance Margins for GEM Inputs
The regulations at 40 CFR 1037.620(d) allow component manufacturers
to conduct testing for vehicle manufacturers, but they do not specify
restrictions for the format of the data. Vehicle manufacturers have
raised concerns about component manufacturers including compliance
margins in GEM inputs--in other words, inputting a value that is
significantly worse than the tested result. They state that many
component suppliers are providing GEM inputs with compliance margins,
rather than raw test results. However, when stacked together, the
compliance margins would result in inappropriately high GEM results
that would not represent the vehicles being produced.
We proposed to note in 40 CFR 1037.501(i) that declared GEM inputs
for fuel maps and aerodynamic drag area will typically include
compliance margins to account for testing variability and that, for
other measured GEM inputs, the declared values will typically be the
measured values, and received comment requesting additional
clarification and providing additional suggested revisions as described
in Chapter 2 of the Response to Comments document. One commenter
suggested that EPA finalize default allowance values at this time,
however we lack adequate data to make a thorough determination on what
these values should be. In addressing manufacturers' concern, it is
important to distinguish between engine fuel maps (which are certified
separately) and other GEM inputs that are not certified. As is
discussed in Section II.B.3, certified engine fuel maps are expected to
include compliance margins to account for manufacturing and test
variability. However, EPA did not expect each of the other GEM input to
have a
[[Page 34335]]
significant compliance margin of its own. (Note that the aerodynamic
bin structure serves to provide an inherent compliance margin for most
vehicles.) Rather, we expected the certifying original equipment
manufacturer (OEM) to include compliance margins in their Family
Emission Limits (FELs) relative to the GEM outputs.
For vehicle GHG standards, the primary role for FEL compliance
margins is to protect against SEA failures. Without a compliance margin
under the Phase 2 regulations, normal production variability would
cause some vehicles to fail, which would require the testing of
additional vehicles. Even if the family ultimately passed the SEA, it
would probably require the manufacturer to test a large number of
vehicles. However, because SEAs and confirmatory tests for particular
components would not target GEM inputs for other components, a modest
vehicle FEL compliance margin determined by the vehicle manufacturer,
that accounts for the component input with the highest uncertainty used
to determine the vehicle FEL, would be sufficient to cover the full
range of uncertainty for all components.
While we are not adopting explicit changes with respect to
compliance margins that were requested in comments, we are finalizing
the revision in Sec. 1037.501(i) as with clarifying edits that, for
other measured GEM inputs, the declared values are typically the
measured values without adjustment, and finalizing a related provision
after consideration of comments on this proposed revision and on
conducting a confirmatory test and SEA for an axle or transmission
apart from a specific vehicle. Specifically, the additional change
clarifies this intent for confirmatory testing in 40 CFR 1037.235(c)(2)
by stating that the results will only affect your vehicle FEL if the
results of our confirmatory testing result in a GEM vehicle emission
value that is higher than the vehicle FEL declared by the manufacturer.
These revisions further obviate a need for component-specific
compliance margins and should thus further clarify that component-
specific suppliers should be providing GEM inputs with raw test
results, rather than values that include an associated compliance
margin. While we do not believe that suppliers should normally include
compliance margins when providing test data to OEMs for GEM inputs, we
do believe they should provide to OEMs some characterization of the
statistical confidence they have in their data. This allows the OEM to
apply an appropriate overall compliance margin for their vehicle FEL.
During a confirmatory test, EPA would compare the GEM results using our
measured inputs with the declared FEL for the vehicles, which means
that the compliance margin for measurement variability should be built
into the FEL of the vehicle. Again, EPA notes that the certified engine
fuel maps are expected to include small compliance margins to account
for manufacturing and test variability.
Finally, none of this is intended to discourage suppliers and OEMs
from entering into commercial agreements related to the accuracy of
test results or SEA performance.
8. SEAs for Axles and Transmissions
Under 40 CFR 1037.320, a selective enforcement audit (SEA) for
axles or transmissions would consist of performing measurements with a
production axle or transmission to determine mean power loss values as
declared for GEM simulations, and running GEM over one or more
applicable duty cycles based on those measured values. The axle or
transmission is considered passing for a given configuration if the new
modeled emission result for every applicable duty cycle is at or below
the modeled emission result corresponding to the declared GEM inputs.
As described below, EPA is revising the provision regarding where an
axle or transmission does not pass.
We believe special provisions are needed for axles and
transmissions given their importance as compliance technologies and a
market structure in which a single axle or transmission could be used
by multiple certifying OEMs. Under the existing SEA regulations, if an
axle or transmission family from an independent supplier fails a SEA,
vehicle production could be disrupted for multiple OEMs and have
serious economic impacts on them. We are finalizing a revision that
will minimize the disruption to vehicle production.
Under the revised provision, if the initial axle or transmission
passes, then the family would pass, and no further testing would be
required. This is the same as under the existing regulations. However,
if the initial axle or transmission does not pass, two additional
production axles or transmissions, as applicable, would need to be
tested. We are finalizing this revision as proposed, except we are
finalizing additional changes to Sec. 1037.320(c) after consideration
of comments received to the proposal in a couple respects. We further
clarified that these additional production axels or transmissions to be
tested could be different axle and transmission configurations within
the family to cover the range of product included in the family. We
also are finalizing an additional clarification in 40 CFR 1037.320(c)
that further address how the results from the SEA will be used to
determine if the manufacturer declared map should be replaced, by
stating that if you fail the audit test for any of the axles or
transmissions tested, the audit result becomes the declared map, also
requiring revision of any analytically derived maps if applicable, and
that these would become official test results for the family. In other
words, this approach would correct the data used by the OEM for their
end-of-year report.
After consideration of comments, we are also finalizing changes to
40 CFR 1037.320(b) to clarify that the test transmission's gear ratios
and not the default ratios in 40 CFR 1036.540 should be used in GEM.
After consideration of comment regarding the lack of an engine defined
for use as a GEM input when a component-level SEA is being performed,
we have specified the use of the default engine map in 40 CFR part
1036, appendix C, and a default torque curve that we have added as
Table 1 to 40 CFR 1037.520. The axle and transmission GEM inputs can
now be determined based on the default map and torque curve. See
Chapter 2 of the Response to Comments for further details on comments
received and our responses.
9. Electric and Hybrid Vehicles in Vocational Applications
Prior to the proposal, manufacturers expressed concern that the
Phase 2 regulations are not specific enough regarding how to classify
hybrid vocational vehicles (see Sec. 1037.140). This is not an issue
for tractors, which are classified based on gross vehicle weight rating
(GVWR). However, vocational vehicles are generally classified by the
class of the engines. Obviously, this approach does not work for
electric vehicle without engines. This approach could also misrepresent
a hybrid vehicle that is able to use an undersized engine. To address
these problems, we proposed changes to Sec. 1037.140(g)(1) to clarify
that the classification for tractors where provisions are the same as
vocational vehicles applies for hybrid and non-hybrid vehicles, and
paragraph (g)(4) to clarify that Class 8 hybrid and electric vehicles
are Heavy HDVs and all other vehicles are classified by GVWR classes.
CARB and Tesla supported the regulation changes proposed in Sec.
1037.140(g). We did not receive any
[[Page 34336]]
adverse comments on these proposed revisions and we are finalizing the
proposed revisions with the addition of ``electric'' to paragraph
(g)(1) for consistency with the rest of the section and an expanded
clarification in paragraph (g)(4)(iii) that Class 8 hybrid and electric
vehicles are considered Heavy HDV, regardless of the engine's primary
intended service class.
CARB suggested tying certification provisions such as warranty and
useful life to the vehicle GVWR to avoid allowing a downsized hybrid
powertrain installed in a heavier vehicle weight class to have shorter
useful life and emission warranty obligations. We note that useful life
(Sec. 1037.105(e)) and warranty (Sec. 1037.120(b)) for vocational
vehicles are defined by vehicle service class (i.e., Light HDV, Medium
HDV, and Heavy HDV) and our final revision to Sec. 1037.140(g)(4)
ensures all Class 8 hybrid and electric vehicles are classified in our
heaviest weight class with the longest useful life and warranty
periods. Consequently, any powertrain in a Class 8 vehicle, including a
downsized hybrid, would be a Heavy HDV and subject to all corresponding
certification provisions for Heavy HDVs.
We also requested comment on alternative approaches, such as
specifying the useful life in hours rather than miles for these
vocational vehicles or allowing electric vehicles to step down one
weight class, with justification from the manufacturer. With respect to
the potential alternative approaches we requested comment on, Ford
supported specifying useful life in hours rather than miles for
vocational vehicles. However, CARB raised questions on how the useful
life in miles correlates to engine hours. Tesla encouraged EPA to
continue to use a single, miles-based criteria for useful life. In
addition, Ford expressed support for allowing electric vehicles to step
down one weight class. We are not taking final action on any of the
potential alternative approaches at this time. Regarding adopting
useful life criteria based on engine hours, we currently lack the data
required to link engine hours to miles for the range of vocational
vehicles. Regarding potentially allowing electric vehicles to step down
one weight class, we currently have concerns that this may allow for
inappropriate useful life and warranty requirements.
Section 1037.140(g)(5) references Sec. 1037.106(f) in specifying
that, in certain circumstances, you may certify vehicles to standards
that apply for a different vehicle service class. We received comments
from EMA and Volvo and agree with the commenters' suggestion to clarify
how our revision to Sec. 1037.140(g)(1) regarding hybrid and electric
tractors interacts with the cross-referenced Sec. 1037.106(f).
Consistent with our explanation at proposal that the current
requirements in Sec. 1037.140(g) applied to all tractors, we are also
finalizing a corresponding clarification in Sec. 1037.106(f)(2)
regarding Class 7 hybrid and electric tractor's ability to certify to
the Class 8 standards, by adding a sentence that ``[t]his applies
equally for hybrid and electric vehicles.'' See Chapter 2 of the
Response to Comments for further details on comments received and our
responses.
10. Vocational Vehicle Segmentation
The Phase 2 regulatory structure applies the primary vocational
standards by subcategory. Manufacturers are generally allowed to
certify vocational vehicles in the particular duty-cycle subcategory
they believe to be most appropriate, consistent with good engineering
judgment.\20\ This process for selecting the correct subcategory is
often called ``segmentation.'' Under this structure, EPA expects
manufacturers to choose a subcategory for each vehicle configuration
that best represents the type of operation that vehicle will actually
experience in use. This is important because several technologies
provide very different emission reductions depending on the actual in-
use drive cycle. For example, stop-start would provide the biggest
emission reductions for urban vehicles and much less reduction for
vehicles that operate primary on long intercity drives.
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\20\ See 40 CFR 1068.5 for specifications on applying good
engineering judgment.
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Vocational vehicles are classified based upon the gross vehicle
weight rating (GVWR) as defined in Sec. 1037.140(g). Once classified,
manufacturers identify the intended regulatory subcategory duty cycles
(i.e., Urban, Multi-purpose, or Regional) for each vocational vehicle
configuration as indicated in Sec. 1037.140(h). There are constraints
for vocational duty cycle and regulatory subcategory, specified in
Sec. 1037.150(z).
Prior to the proposal, manufacturers raised concerns about the
impact of this structure on their ability to plan for and monitor
compliance. They suggested that more objective and quantitative ``good
engineering judgment'' criteria would be helpful. In response to these
concerns, EPA proposed an interim ``safe harbor'' provision in Sec.
1037.150(bb) for vocational vehicle segmentation. Under the proposal,
manufacturers meeting the safe harbor criteria would be presumed to
have applied good engineering judgment, and we explained that we
thought the criteria were consistent with the intent of the Phase 2
program and would not allow manufacturers to reduce the effective
stringency the standards.
The first principle of the proposed safe harbor was that any
vehicle could be classified as Multi-purpose. The Multi-purpose duty
cycle weighting factors include significant weightings for highway
operation, lower speed transient operation, and idle. Thus, it would
not generally overvalue an individual technology. The second principle
of the proposed safe harbor was that vehicles not classified as Multi-
purpose should not be exclusively Regional or Urban. We proposed a
quantitative measure that evaluates the ratio of Regional vehicles to
Urban vehicles within an averaging set. Specifically, we proposed that
the ratio of Regional vehicles to Urban vehicles must be between 1:5
and 5:1. EPA requested comment on the proposed approach overall and the
range of acceptable ratios.
CARB supported the proposed provision of allowing any vocational
vehicle to be classified as Multi-purpose. However, both EMA and CARB
questioned the ratios for vocational vehicle categories in the proposed
provisions of Sec. 1037.150(bb). EMA commented that the proposed
ratios were ``arbitrary'' and may not be represent a manufacturer's
model mix during any specific year. Instead, EMA suggested that more
appropriate ``good engineering judgment'' would be to base the vehicle
category on ``the duty cycle weighting under which it performs most
efficiently in GEM.'' CARB commented that the ratio could inadvertently
drive manufacturers to certify the vehicles with an inappropriate duty
cycle and recommended all vehicles be certified as Multi-purpose unless
the manufacturer could provide ``good justification'' for a Regional or
Urban categorization.
We are finalizing a revision in Sec. 1037.140(h) and throughout
Sec. 1037.150(z) to replace ``duty cycle'' with the term ``regulatory
subcategory'' that more appropriately reflects the intent of
classifying a vehicle and its connection to a standard. Additionally,
after considering the comments, EPA is finalizing one principle of the
safe harbor provision proposed as Sec. 1037.150(bb); specifically, the
paragraph that allows manufacturers to select the Multi-purpose
subcategory for any vocational vehicle, unless otherwise
[[Page 34337]]
specified in Sec. 1037.150(z).\21\ As noted previously, selecting this
subcategory and associated duty cycle would require technologies that
reduce emissions across all operation (i.e., high speed, lower speed
transient, and idle) and we believe it is an appropriate default duty
cycle if a manufacturer is unsure of the final vehicle application when
applying the good engineering judgment provision of Sec. 1037.140(h).
We agree with the concerns expressed by CARB and EMA and are not
finalizing the ratios of Regional to Urban vehicles in paragraph Sec.
1037.150(bb)(2) of the proposed safe harbor provision. Instead, as
discussed further below, we continue to rely on the constraints listed
in Sec. 1037.150(z) to guide manufacturers in identifying
[…truncated; see source link]Indexed from Federal Register on June 29, 2021.
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