provisions apply for spark-ignition engines that control air-fuel
ratios at or near stoichiometry starting with model year 2027:
    (1) Catalyst bed temperature during extended idle may not fall
below 350 [deg]C, or a lower temperature that we approve. Describe how
you designed your engine to meet this requirement in your application
for certification. You may ask us to approve alternative strategies to
prevent emissions from increasing during idle.
    (2) In addition to the information requirements of Sec.
1036.205(b), describe why you rely on any AECDs instead of other engine
designs for thermal protection of catalyst or other emission-related
components. Also describe the accuracy of any modeled or measured
temperatures used to activate the AECD. We may ask you to submit a
second-by-second comparison of any modeled and measured component
temperatures as part of your application for certification.

Sec.  1036.120  Emission-related warranty requirements.

    (a) General requirements. You must warrant to the ultimate
purchaser and each subsequent purchaser that the new engine, including
all parts of its emission control system, meets two conditions:
    (1) It is designed, built, and equipped so it conforms at the time
of sale to the ultimate purchaser with the requirements of this part.
    (2) It is free from defects in materials and workmanship that may
keep it from meeting these requirements.
    (b) Warranty period. Your emission-related warranty must be valid
for at least as long as the minimum warranty periods listed in this
paragraph (b) in vehicle miles, or hours of engine operation, or years
in service, whichever comes first. You may offer an emission-related
warranty more generous than we require. The emission-related warranty
for the engine may not be shorter than any published warranty you offer
without charge for the engine. Similarly, the emission-related warranty
for any component may not be shorter than any published warranty you
offer without charge for that component. If an extended warranty
requires owners to pay for a portion of repairs, those terms apply in
the same manner to the emission-related warranty. The warranty period
begins when the vehicle is placed into service. The following minimum
warranty periods apply:

                                 Table 1 to Paragraph (b) of Sec.   1036.120--Warranty by Primary Intended Service Class
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Model year 2026 and earlier                      Model year 2027 and later
             Primary intended service class              -----------------------------------------------------------------------------------------------
                                                              Mileage          Years           Hours          Mileage          Years           Hours
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spark-Ignition HDE......................................          50,000               5  ..............         160,000              10           8,000
Light HDE...............................................          50,000               5  ..............         210,000              10          10,000
Medium HDE..............................................         100,000               5  ..............         280,000              10          14,000
Heavy HDE...............................................         100,000               5  ..............         450,000              10          22,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (c) Components covered. The emission-related warranty covers all
components listed in 40 CFR part 1068, appendix A, and components from
any other system you develop to control emissions. The emission-related
warranty covers any components, regardless of the company that produced
them, that are the original components or the same design as components
from the certified configuration.
    (d) Limited applicability. You may deny warranty claims under this
section if the operator caused the problem through improper maintenance
or use, subject to the provisions in Sec.  1036.125 and 40 CFR
1068.115.
    (e) Owners manual. Describe in the owners manual the emission-
related warranty provisions from this section that apply to the engine.

Sec.  1036.125  Maintenance instructions and allowable maintenance.

    Maintenance includes any inspection, adjustment, cleaning, repair,
or replacement of components and is classified as either emission-
related or not emission-related and each of these can be classified as
either scheduled or

unscheduled. Further, some emission-related maintenance is also
classified as critical emission-related maintenance. Give the ultimate
purchaser of each new engine written instructions for maintaining and
using the engine. As described in paragraph (h) of this section, these
instructions must identify how owners properly maintain and use engines
to clarify responsibilities for regulatory requirements such as
emission-related warranty and defect reporting.
    (a) Critical emission-related maintenance. Critical emission-
related maintenance includes any adjustment, cleaning, repair, or
replacement of components listed in paragraph (a)(2) of this section.
Critical emission-related maintenance may also include other
maintenance that you determine is critical, including maintenance on
other emission-related components as described in 40 CFR part 1068,
appendix A, if we approve it in advance. You may perform scheduled
critical emission-related maintenance during service accumulation on
your emission-data engines at the intervals you specify.
    (1) Maintenance demonstration. You must demonstrate that the
maintenance is reasonably likely to be done at your recommended
intervals on in-use engines. We will accept DEF replenishment as
reasonably likely to occur if your engine meets the specifications in
Sec.  1036.111. We will accept other scheduled maintenance as
reasonably likely to occur if you satisfy any of the following
conditions:
    (i) You present data showing that, if a lack of maintenance
increases emissions, it also unacceptably degrades the engine's
performance.
    (ii) You design and produce your engines with a system we approve
that displays a visible signal to alert drivers that maintenance is
due, either as a result of component failure or the appropriate degree
of engine or vehicle operation. The signal must clearly display
``maintenance needed'', ``check engine'', or a similar message that we
approve. The signal must be continuous while the engine is operating
and not be easily eliminated without performing the specified
maintenance. Your maintenance instructions must specify resetting the
signal after completing the specified maintenance. We must approve the
method for resetting the signal. You may not design the system to be
less effective at the end of the useful life. If others install your
engine in their vehicle, you may rely on installation instructions to
ensure proper mounting and operation of the display. Disabling or
improperly resetting the system for displaying these maintenance-
related signals without performing the indicated maintenance violates
the tampering prohibition in 42 U.S.C. 7522(a)(3).
    (iii) You present survey data showing that at least 80 percent of
engines in the field get the maintenance you specify at the recommended
intervals.
    (iv) You provide the maintenance free of charge and clearly say so
in your maintenance instructions.
    (v) You otherwise show us that the maintenance is reasonably likely
to be done at the recommended intervals.
    (2) Minimum scheduled maintenance intervals. You may not schedule
critical emission-related maintenance more frequently than the minimum
intervals specified or allowed in this paragraph (a), except as
specified in paragraph (g) of this section. The minimum intervals
specified for each component applies to actuators, sensors, tubing,
valves, and wiring associated with that component, except as specified.

Table 1 to Paragraph (a)(2) of Sec.   1036.125--Minimum Scheduled Maintenance Intervals for Replacement in Miles
                                                   (or Hours)
----------------------------------------------------------------------------------------------------------------
                                                  Spark-ignition
                   Components                           HDE          Light HDE      Medium HDE       Heavy HDE
----------------------------------------------------------------------------------------------------------------
Spark plugs.....................................    25,000 (750)  ..............  ..............  ..............
DEF filters.....................................  ..............         100,000         100,000         100,000
                                                                         (3,000)         (3,000)         (3,000)
Crankcase ventilation valves and filters........  60,000 (1,800)  60,000 (1,800)  60,000 (1,800)  60,000 (1,800)
Ignition wires and coils........................  50,000 (1,500)  ..............  ..............  ..............
Oxygen sensors..................................  80,000 (2,400)  ..............  ..............  ..............
Air injection system components.................         110,000  ..............  ..............  ..............
                                                         (3,300)
Sensors, actuators, and related control modules          100,000         100,000         150,000         150,000
 that are not integrated into other systems.....         (3,000)         (3,000)         (4,500)         (4,500)
Particulate filtration systems (other than               100,000  100,000 3,000)  250,000 7,500)         250,000
 filter substrates).............................         (3,000)                                         (7,500)
Catalyst systems (other than catalyst                    110,000         110,000  185,000 5,550)         435,000
 substrates), fuel injectors, electronic control         (3,300)         (3,300)                        (13,050)
 modules, hybrid system components,
 turbochargers, and EGR system components
 (including filters and coolers) ...............
Catalyst substrates and particulate filter               200,000         270,000         350,000         650,000
 substrates.....................................        (10,000)        (13,000)        (17,000)        (32,000)
----------------------------------------------------------------------------------------------------------------

    Table 2 to Paragraph (a)(2) of Sec.   1036.125--Minimum Scheduled Maintenance Intervals for Adjustment or
                                                    Cleaning
----------------------------------------------------------------------------------------------------------------
                                                      Accumulated miles (hours) for components
                                   -----------------------------------------------------------------------------
             Component              Spark-ignition
                                          HDE          Light HDE          Medium HDE             Heavy HDE
----------------------------------------------------------------------------------------------------------------
Spark plugs.......................    25,000 (750)
EGR-related filters and coolers,    50,000 (1,500)  50,000 (1,500)  50,000 (1,500).......  50,000 (1,500)
 fuel injectors, and crankcase
 ventilation valves and filters.
DEF filters.......................  ..............  50,000 (1,500)  50,000 (1,500).......  50,000 (1,500)

Ignition wires and coils..........  50,000 (1,500)
Oxygen sensors....................  80,000 (2,400)
Air injection system components...         100,000
                                           (3,000)
Catalyst system components, EGR            100,000         100,000  100,000 (3,000), then  100,000 (3,000), then
 system components (other than             (3,000)         (3,000)   50,000 (4,500).        150,000 (4,500)
 filters or coolers), particulate
 filtration system components, and
 turbochargers.
----------------------------------------------------------------------------------------------------------------

    (3) New technology. You may ask us to approve scheduled critical
emission-related maintenance of components not identified in paragraph
(a)(2) of this section that is a direct result of the implementation of
new technology not used in model year 2020 or earlier engines, subject
to the following provisions:
    (i) Your request must include your recommended maintenance
interval, including data to support the need for the maintenance, and a
demonstration that the maintenance is likely to occur at the
recommended interval using one of the conditions specified in paragraph
(a)(1) of this section.
    (ii) For any such new technology, we will publish a Federal
Register notice based on information you submit and any other available
information to announce that we have established new allowable minimum
maintenance intervals. Any manufacturer objecting to our decision may
ask for a hearing (see Sec.  1036.820).
    (4) System components. The following provisions clarify which
components are included in certain systems:
    (i) Catalyst system refers to the aftertreatment assembly used for
gaseous emission control and generally includes catalyst substrates,
substrate housings, exhaust gas temperature sensors, gas concentration
sensors, and related control modules. SCR-based catalyst systems also
include DEF level sensors, DEF quality sensors, and DEF temperature
sensors.
    (ii) Particulate filtration system refers to the aftertreatment
assembly used for exhaust PM filtration and generally includes filter
substrates, substrate housings, pressure sensors, pressure lines and
tubes, exhaust gas temperature sensors, fuel injectors for active
regeneration, and related control modules.
    (b) Recommended additional maintenance. You may recommend any
amount of critical emission-related maintenance that is additional to
what we approve in paragraph (a) of this section, as long as you state
clearly that the recommended additional maintenance steps are not
necessary to keep the emission-related warranty valid. If operators do
the maintenance specified in paragraph (a) of this section, but not the
recommended additional maintenance, this does not allow you to
disqualify those engines from in-use testing or deny a warranty claim.
Do not take these maintenance steps during service accumulation on your
emission-data engines.
    (c) Special maintenance. You may specify more frequent maintenance
to address problems related to special situations, such as atypical
engine operation. For example, you may specify more frequent
maintenance if operators fuel the engine with an alternative fuel such
as biodiesel. You must clearly state that this special maintenance is
associated with the special situation you are addressing. We may
disapprove your maintenance instructions if we determine that you have
specified special maintenance steps to address engine operation that is
not atypical, or that the maintenance is unlikely to occur in use. If
we determine that certain maintenance items do not qualify as special
maintenance under this paragraph (c), you may identify them as
recommended additional maintenance under paragraph (b) of this section.
    (d) Noncritical emission-related maintenance. You may specify any
amount of emission-related inspection or other maintenance that is not
approved critical emission-related maintenance under paragraph (a) of
this section, subject to the provisions of this paragraph (d).
Noncritical emission-related maintenance generally includes maintenance
on the components we specify in 40 CFR part 1068, appendix A, that is
not covered in paragraph (a) of this section. You must state in the
owners manual that these steps are not necessary to keep the emission-
related warranty valid. If operators fail to do this maintenance, this
does not allow you to disqualify those engines from in-use testing or
deny a warranty claim. Do not take these inspection or other
maintenance steps during service accumulation on your emission-data
engines.
    (e) Maintenance that is not emission-related. You may schedule any
amount of maintenance unrelated to emission controls that is needed for
proper functioning of the engine. This might include adding engine oil;
changing air, fuel, or oil filters; servicing engine-cooling systems;
adjusting idle speed, governor, engine bolt torque, valve lash,
injector lash, timing, or tension of air pump drive belts; and
lubricating the heat control valve in the exhaust manifold. For
maintenance that is not emission-related, you may perform the
maintenance during service accumulation on your emission-data engines
at the least frequent intervals that you recommend to the ultimate
purchaser (but not the intervals recommended for special situations).
    (f) [Reserved]
    (g) Payment for scheduled maintenance. Owners are responsible for
properly maintaining their engines, which generally includes paying for
scheduled maintenance. However, you may commit to paying for scheduled
maintenance as described in paragraph (a)(1)(iv) of this section to
demonstrate that the maintenance will occur. You may also schedule
maintenance not otherwise allowed by paragraph (a)(2) of this section
if you pay for it. You must pay for scheduled maintenance on any
component during the useful life if it meets all the following
conditions:
    (1) Each affected component was not in general use on similar
engines before 1980.
    (2) The primary function of each affected component is to reduce
emissions.
    (3) The cost of the maintenance is more than 2 percent of the price
of the engine.

    (4) Failure to perform the maintenance would not cause clear
problems that would significantly degrade the engine's performance.
    (h) Owners manual. Include the following maintenance-related
information in the owners manual, consistent with the requirements of
this section:
    (1) Clearly describe the scheduled maintenance steps, consistent
with the provisions of this section, using nontechnical language as
much as possible. Include a list of components for which you will cover
scheduled replacement costs.
    (2) Identify all maintenance you consider necessary for the engine
to be considered properly maintained for purposes of making valid
warranty claims. Describe what documentation you consider appropriate
for making these demonstrations. Note that you may identify failure to
repair critical emission-related components as improper maintenance if
the repairs are related to an observed defect. Your maintenance
instructions under this section may not require components or service
identified by brand, trade, or corporate name. Also, do not directly or
indirectly require that the engine be serviced by your franchised
dealers or any other service establishments with which you have a
commercial relationship. However, you may disregard these limitations
on your maintenance requirements if you do one of the following things:
    (i) Provide a component or service without charge under the
purchase agreement.
    (ii) Get us to waive this prohibition in the public's interest by
convincing us the engine will work properly only with the identified
component or service.
    (3) Describe how the owner can access the OBD system to
troubleshoot problems and find emission-related diagnostic information
and codes stored in onboard monitoring systems as described in Sec.
1036.110(b) and (c). These instructions must at a minimum include
identification of the OBD communication protocol used, location and
type of OBD connector, brief description of what OBD is (including type
of information stored, what a MIL is, and explanation that some MILs
may self-extinguish), and a note that generic scan tools can provide
engine maintenance information.
    (4) Describe the elements of the emission control system and
provide an overview of how they function.
    (5) Include one or more diagrams of the engine and its emission-
related components with the following information:
    (i) The flow path for intake air and exhaust gas.
    (ii) The flow path of evaporative and refueling emissions for
spark-ignition engines, and DEF for compression-ignition engines, as
applicable.
    (iii) The flow path of engine coolant if it is part of the emission
control system described in the application for certification.
    (iv) The identity, location, and arrangement of relevant sensors,
DEF heater and other DEF delivery components, and other critical
emission-related components. Terminology to identify components must be
consistent with codes you use for the OBD system.
    (6) Include one or more exploded-view drawings that allow the owner
to identify the following components: EGR valve, EGR actuator, EGR
cooler, all emission sensors (such as NOX sensors and soot
sensors), temperature and pressure sensors (such as sensors related to
EGR, DPF, DOC, and SCR and DEF), quality sensors, DPF filter, DOC, SCR
catalyst, fuel (DPF-related) and DEF dosing units and components (e.g.,
pumps, metering units, filters, nozzles, valves, injectors),
aftertreatment-related control modules, any other DEF delivery-related
components (such as delivery lines and freeze-protection components),
and separately replaceable aftertreatment-related wiring harnesses.
Terminology to identify components must be consistent with codes you
use for the OBD system. Include part numbers for sensors and filters
related to SCR and DPF systems for the current model year or any
earlier model year.
    (7) Include the following statement: ``Technical service bulletins,
emission-related recalls, and other information for your engine may be
available at www.nhtsa.gov/recalls.''
    (8) Include a troubleshooting guide to address the following
warning signals related to SCR inducement:
    (i) The inducement derate schedule (including indication that
inducements will begin prior to the DEF tank being completely empty).
    (ii) The meaning of any trouble lights that indicate specific
problems (e.g., DEF level).
    (iii) A description of the three types of SCR-related derates (DEF
quality, DEF quality and tampering) and that further information on the
inducement cause (e.g., trouble codes) is available using the OBD
system.
    (9) Describe how to access OBD fault codes related to DPF-related
derates.
    (10) Identify a website for the service information required in 40
CFR 86.010-38(j).

Sec.  1036.130  Installation instructions for vehicle manufacturers.

    (a) If you sell an engine for someone else to install in a vehicle,
give the engine installer instructions for installing it consistent
with the requirements of this part. Include all information necessary
to ensure that an engine will be installed in its certified
configuration.
    (b) Make sure these instructions have the following information:
    (1) Include the heading: ``Emission-related installation
instructions''.
    (2) State: ``Failing to follow these instructions when installing a
certified engine in a heavy-duty motor vehicle violates federal law,
subject to fines or other penalties as described in the Clean Air
Act.''
    (3) Provide all instructions needed to properly install the exhaust
system and any other components. Include any appropriate instructions
for configuring the exhaust system in the vehicle to allow for
collecting emission samples for in-use testing where that is practical.
    (4) Describe any necessary steps for installing any diagnostic
system required under Sec.  1036.110.
    (5) Describe how your certification is limited for any type of
application. For example, if you certify Heavy HDE to the
CO2 standards using only transient FTP testing, you must
make clear that the engine may not be installed in tractors.
    (6) Describe any other instructions to make sure the installed
engine will operate according to design specifications in your
application for certification. This may include, for example,
instructions for installing aftertreatment devices when installing the
engines.
    (7) Give the following instructions if you do not ship diesel
exhaust fluid tanks with your engines:
    (i) Specify that vehicle manufacturers must install diesel exhaust
fluid tanks meeting the specifications of Sec.  1036.115(i).
    (ii) Describe how vehicle manufacturers must install diesel exhaust
fluid tanks with sensors as needed to meet the requirements of
Sec. Sec.  1036.110 and 1036.111.
    (8) State: ``If you install the engine in a way that makes the
engine's emission control information label hard to read during normal
engine maintenance, you must place a duplicate label on the vehicle, as
described in 40 CFR 1068.105.''
    (9) Describe how vehicle manufacturers need to apply stickers to
qualifying vehicles as described in Sec.  1036.136 if you certify
engines to the

Clean Idle NOX standard of Sec.  1036.104(b).
    (c) Give the vehicle manufacturer fuel map results as described in
Sec.  1036.505(b).
    (d) You do not need installation instructions for engines that you
install in your own vehicles.
    (e) Provide instructions in writing or in an equivalent format. For
example, you may post instructions on a publicly available website for
downloading or printing. If you do not provide the instructions in
writing, explain in your application for certification how you will
ensure that each installer is informed of the installation
requirements.

Sec.  1036.135  Labeling.

    (a) Assign each engine a unique identification number and
permanently affix, engrave, or stamp it on the engine in a legible way.
    (b) At the time of manufacture, affix a permanent and legible label
identifying each engine. The label must meet the requirements of 40 CFR
1068.45.
    (c) The label must--
    (1) Include the heading ``EMISSION CONTROL INFORMATION''.
    (2) Include your full corporate name and trademark. You may
identify another company and use its trademark instead of yours if you
comply with the branding provisions of 40 CFR 1068.45.
    (3) Include EPA's standardized designation for the engine family.
    (4) Identify the primary intended service class.
    (5) State the engine's displacement (in liters); however, you may
omit this from the label if all the engines in the engine family have
the same per-cylinder displacement and total displacement.
    (6) State the date of manufacture [DAY (optional), MONTH, and
YEAR]; however, you may omit this from the label if you stamp, engrave,
or otherwise permanently identify it elsewhere on the engine, in which
case you must also describe in your application for certification where
you will identify the date on the engine.
    (7) State the NOX FEL to which the engines are certified
if applicable. Identify the Clean Idle standard if you certify the
engine to the NOX standard of Sec.  1036.104(b).
    (8) State: ``THIS ENGINE COMPLIES WITH U.S. EPA REGULATIONS FOR
[MODEL YEAR] HEAVY-DUTY HIGHWAY ENGINES.''
    (9) Identify any limitations on your certification. For example, if
you certify Heavy HDE to the CO2 standards using only
steady-state testing, include the statement ``TRACTORS ONLY''.
Similarly, for engines with one or more approved AECDs for emergency
vehicle applications under Sec.  1036.115(h)(4), the statement: ``THIS
ENGINE IS FOR INSTALLATION IN EMERGENCY VEHICLES ONLY''.
    (d) You may add information to the emission control information
label as follows:
    (1) You may identify other emission standards that the engine meets
or does not meet. You may add the information about the other emission
standards to the statement we specify, or you may include it in a
separate statement.
    (2) You may add other information to ensure that the engine will be
properly maintained and used.
    (3) You may add appropriate features to prevent counterfeit labels.
For example, you may include the engine's unique identification number
on the label.
    (e) You may ask us to approve modified labeling requirements in
this part if you show that it is necessary or appropriate. We will
approve your request if your alternate label is consistent with the
requirements of this part. We may also specify modified labeling
requirements to be consistent with the intent of 40 CFR part 1037.
    (f) If you obscure the engine label while installing the engine in
the vehicle such that the label cannot be read during normal
maintenance, you must place a duplicate label on the vehicle. If others
install your engine in their vehicles in a way that obscures the engine
label, we require them to add a duplicate label on the vehicle (see 40
CFR 1068.105); in that case, give them the number of duplicate labels
they request and keep the following records for at least five years:
    (1) Written documentation of the request from the vehicle
manufacturer.
    (2) The number of duplicate labels you send for each engine family
and the date you sent them.

Sec.  1036.136  Clean Idle sticker.

    (a) Design and produce stickers showing that your engines meet the
federal Clean Idle standard if you certify engines to the Clean Idle
NOX standard of Sec.  1036.104(b). The sticker must--
    (1) Meet the requirements of 40 CFR 1068.45 for permanent labels.
The preferred location for sticker placement is on the driver's side of
the hood.
    (2) Include one or both of your corporate name and trademark.
    (3) Identify that the engine is qualified to meet the federal Clean
Idle NOX standard.
    (4) Include a serial number or other method to confirm that
stickers have been properly applied to vehicles.
    (b) The following provisions apply for placing Clean Idle stickers
on vehicles with installed engines that have been certified to the
NOX standard of Sec.  1036.104(b):
    (1) If you install engines in vehicles you produce, you must apply
a sticker to each vehicle certified to the Clean Idle standard.
    (2) If you ship engines for others to install in vehicles, include
in your purchasing documentation the manufacturer's request for a
specific number of labels corresponding to the number of engines
ordered. Supply the vehicle manufacturer with exactly one sticker for
each shipped engine certified to the Clean Idle standard. Prepare your
emission-related installation instructions to ensure that vehicle
manufacturers meet all application requirements. Keep the following
records for at least five years:
    (i) Written documentation of the vehicle manufacturer's request for
stickers.
    (ii) Tracking information for stickers you send and the date you
sent them.
    (c) The provisions in 40 CFR 1068.101 apply for the Clean Idle
sticker in the same way that those provisions apply for emission
control information labels.

Sec.  1036.140  Primary intended service class and engine cycle.

    You must identify a single primary intended service class for each
engine family that best describes vehicles for which you design and
market the engine, as follows:
    (a) Divide compression-ignition engines into primary intended
service classes based on the following engine and vehicle
characteristics:
    (1) Light HDE includes engines that are not designed for rebuild
and do not have cylinder liners. Vehicle body types in this group might
include any heavy-duty vehicle built from a light-duty truck chassis,
van trucks, multi-stop vans, and some straight trucks with a single
rear axle. Typical applications would include personal transportation,
light-load commercial delivery, passenger service, agriculture, and
construction. The GVWR of these vehicles is normally at or below 19,500
pounds.
    (2) Medium HDE includes engines that may be designed for rebuild
and may have cylinder liners. Vehicle body types in this group would
typically include school buses, straight trucks with single rear axles,
city tractors, and a variety of special purpose vehicles such as small
dump trucks, and refuse trucks. Typical applications would include
commercial short haul and intra-city delivery and pickup. Engines

in this group are normally used in vehicles whose GVWR ranges from
19,501 to 33,000 pounds.
    (3) Heavy HDE includes engines that are designed for multiple
rebuilds and have cylinder liners. Vehicles in this group are normally
tractors, trucks, straight trucks with dual rear axles, and buses used
in inter-city, long-haul applications. These vehicles normally exceed
33,000 pounds GVWR.
    (b) Divide spark-ignition engines into primary intended service
classes as follows:
    (1) Spark-ignition engines that are best characterized by paragraph
(a)(1) or (2) of this section are in a separate Spark-ignition HDE
primary intended service class.
    (2) Spark-ignition engines that are best characterized by paragraph
(a)(3) of this section are included in the Heavy HDE primary intended
service class along with compression-ignition engines. Gasoline-fueled
engines are presumed not to be characterized by paragraph (a)(3) of
this section; for example, vehicle manufacturers may install some
number of gasoline-fueled engines in Class 8 trucks without causing the
engine manufacturer to consider those to be Heavy HDE.
    (c) References to ``spark-ignition standards'' in this part relate
only to the spark-ignition engines identified in paragraph (b)(1) of
this section. References to ``compression-ignition standards'' in this
part relate to compression-ignition engines, to spark-ignition engines
optionally certified to standards that apply to compression-ignition
engines, and to all engines identified under paragraph (b)(2) of this
section as Heavy HDE.

Sec.  1036.150  Interim provisions.

    The provisions in this section apply instead of other provisions in
this part. This section describes when these interim provisions expire,
if applicable.
    (a) Transitional ABT credits for NOX emissions. You may generate
NOX credits from model year 2026 and earlier engines and use
those as transitional credits for model year 2027 and later engines
using any of the following methods:
    (1) Discounted credits. Generate discounted credits by certifying
any model year 2022 through 2026 engine family to meet all the
requirements that apply under 40 CFR part 86, subpart A. Calculate
discounted credits for certifying engines in model years 2027 through
2029 as described in Sec.  1036.705 relative to a NOX
emission standard of 200 mg/hp[middot]hr and multiply the result by
0.6. You may not use discounted credits for certifying model year 2030
and later engines.
    (2) Partial credits. Generate partial credits by certifying any
model year 2024 through 2026 compression-ignition engine family as
described in this paragraph (a)(2). You may not use partial credits for
certifying model year 2033 and later engines. Certify engines for
partial credits to meet all the requirements that apply under 40 CFR
part 86, subpart A, with the following adjustments:
    (i) Calculate credits as described in Sec.  1036.705 relative to a
NOX emission standard of 200 mg/hp[middot]hr using the
appropriate useful life mileage from 40 CFR 86.004-2. Your declared
NOX family emission limit applies for the FTP and SET duty
cycles.
    (ii) Engines must meet a NOX standard when tested over
the Low Load Cycle as described in Sec.  1036.514. Engines must also
meet an off-cycle NOX standard as specified in Sec.
1036.104(a)(3). Calculate the NOX family emission limits for
the Low Load Cycle and for off-cycle testing as described in Sec.
1036.104(c)(3) with StdFTPNOx set to 35 mg/hp[middot]hr and
Std[cycle]NOx set to the values specified in Sec.
1036.104(a)(2) or (3), respectively. No standard applies for HC, PM,
and CO emissions for the Low Load Cycle or for off-cycle testing, but
you must record measured values for those pollutants and include those
measured values where you report NOX emission results.
    (iii) For engines selected for in-use testing, we may specify that
you perform testing as described in 40 CFR part 86, subpart T, or as
described in subpart E of this part.
    (iv) Add the statement ``Partial credit'' to the emission control
information label.
    (3) Full credits. Generate full credits by certifying any model
year 2024 through 2026 engine family to meet all the requirements that
apply under this part. Calculate credits as described in Sec.  1036.705
relative to a NOX emission standard of 200 mg/hp[middot]hr.
You may not use full credits for certifying model year 2033 and later
engines.
    (4) 2026 service class pull-ahead credits. Generate credits from
diesel-fueled engines under this paragraph (a)(4) by certifying all
your model year 2026 diesel-fueled Heavy HDE to meet all the
requirements that apply under this part, with a NOX family
emission limit for FTP testing at or below 50 mg/hp[middot]hr.
Calculate credits as described in Sec.  1036.705 relative to a
NOX emission standard of 200 mg/hp[middot]hr. You may use
credits generated under this paragraph (a)(4) through model year 2034,
but not for later model years. Credits generated by Heavy HDE may be
used for certifying Medium HDE after applying a 10 percent discount
(multiply credits by 0.9). Engine families using credits generated
under this paragraph (a)(4) are subject to a NOX FEL cap of
50 mg/hp[middot]hr for FTP testing.
    (b) Model year 2014 N2O standards. In model year 2014 and earlier,
manufacturers may show compliance with the N2O standards
using an engineering analysis. This allowance also applies for later
families certified using carryover CO2 data from model 2014
consistent with Sec.  1036.235(d).
    (c) Engine cycle classification. Through model year 2020, engines
meeting the definition of spark-ignition, but regulated as compression-
ignition engines under Sec.  1036.140, must be certified to the
requirements applicable to compression-ignition engines under this
part. Such engines are deemed to be compression-ignition engines for
purposes of this part. Similarly, through model year 2020, engines
meeting the definition of compression-ignition, but regulated as Otto-
cycle under 40 CFR part 86 must be certified to the requirements
applicable to spark-ignition engines under this part. Such engines are
deemed to be spark-ignition engines for purposes of this part. See
Sec.  1036.140 for provisions that apply for model year 2021 and later.
    (d) Small manufacturers. The greenhouse gas standards of this part
apply on a delayed schedule for manufacturers meeting the small
business criteria specified in 13 CFR 121.201. Apply the small business
criteria for NAICS code 336310 for engine manufacturers with respect to
gasoline-fueled engines and 333618 for engine manufacturers with
respect to other engines; the employee limits apply to the total number
employees together for affiliated companies. Qualifying small
manufacturers are not subject to the greenhouse gas emission standards
in Sec.  1036.108 for engines with a date of manufacture on or after
November 14, 2011 but before January 1, 2022. In addition, qualifying
small manufacturers producing engines that run on any fuel other than
gasoline, E85, or diesel fuel may delay complying with every later
greenhouse gas standard under this part by one model year. Small
manufacturers may certify their engines and generate emission credits
under this part before standards start to apply, but only if they
certify their entire U.S.-directed production volume within that
averaging set for that model year. Note that engines not yet subject to
standards must nevertheless supply fuel maps to vehicle manufacturers
as described in paragraph (n) of this

section. Note also that engines produced by small manufacturers are
subject to criteria pollutant standards.
    (e) Alternate phase-in standards for greenhouse gas emissions.
Where a manufacturer certifies all of its model year 2013 compression-
ignition engines within a given primary intended service class to the
applicable alternate standards of this paragraph (e), its compression-
ignition engines within that primary intended service class are subject
to the standards of this paragraph (e) for model years 2013 through
2016. This means that once a manufacturer chooses to certify a primary
intended service class to the standards of this paragraph (e), it is
not allowed to opt out of these standards.

           Table 1 to Paragraph (e) of Sec.   1036.150--Alternate Phase-In Standards (g/hp[middot]hr)
----------------------------------------------------------------------------------------------------------------
          Vehicle type                Model years          Light HDE          Medium HDE           Heavy HDE
----------------------------------------------------------------------------------------------------------------
Tractors........................  2013-2015.........  NA................  512 g/hp[middot]hr  485 g/
                                  2016 and later \a\  NA................  487 g/hp[middot]hr   hp[middot]hr.
                                                                                460 g/
                                                                                hp[middot]hr.
Vocational......................  2013-2015.........  618 g/hp[middot]hr  618 g/hp[middot]hr  577 g/
                                  2016 through 2020   576 g/hp[middot]hr  576 g/hp[middot]hr   hp[middot]hr.
                                   \a\.                                                       555 g/
                                                                                hp[middot]hr.
----------------------------------------------------------------------------------------------------------------
\a\ Note: these alternate standards for 2016 and later are the same as the otherwise applicable standards for
  2017 through 2020.

    (f) [Reserved]
    (g) Default deterioration factors for greenhouse gas standards. You
may use default deterioration factors (DFs) without performing your own
durability emission tests or engineering analysis as follows:
    (1) You may use a default additive DF of 0.0 g/hp[middot]hr for
CO2 emissions from engines that do not use advanced or off-
cycle technologies. If we determine it to be consistent with good
engineering judgment, we may allow you to use a default additive DF of
0.0 g/hp[middot]hr for CO2 emissions from your engines with
advanced or off-cycle technologies.
    (2) You may use a default additive DF of 0.010 g/hp[middot]hr for
N2O emissions from any engine through model year 2021, and
0.020 g/hp[middot]hr for later model years.
    (3) You may use a default additive DF of 0.020 g/hp[middot]hr for
CH4 emissions from any engine.
    (h) Advanced-technology credits. If you generate CO2
credits from model year 2020 and earlier engines certified for advanced
technology, you may multiply these credits by 1.5.
    (i) CO2 credits for low N2O emissions. If you certify your model
year 2014, 2015, or 2016 engines to an N2O FEL less than
0.04 g/hp[middot]hr (provided you measure N2O emissions from
your emission-data engines), you may generate additional CO2
credits under this paragraph (i). Calculate the additional
CO2 credits from the following equation instead of the
equation in Sec.  1036.705:
[GRAPHIC] [TIFF OMITTED] TR24JA23.012

    (j) Alternate standards under 40 CFR part 86. This paragraph (j)
describes alternate emission standards for loose engines certified
under 40 CFR 86.1819-14(k)(8). The standards of Sec.  1036.108 do not
apply for these engines. The standards in this paragraph (j) apply for
emissions measured with the engine installed in a complete vehicle
consistent with the provisions of 40 CFR 86.1819-14(k)(8)(vi). The only
requirements of this part that apply to these engines are those in this
paragraph (j), Sec. Sec.  1036.115 through 1036.135, 1036.535, and
1036.540.
    (k) Limited production volume allowance under ABT. You may produce
a limited number of Heavy HDE that continue to meet the standards that
applied under 40 CFR 86.007-11 in model years 2027 through 2029. The
maximum number of engines you may produce under this limited production
allowance is 5 percent of the annual average of your actual U.S.-
directed production volume of Heavy HDE in model years 2023-2025.
Engine certification under this paragraph (k) is subject to the
following conditions and requirements:
    (1) Engines must meet all the standards and other requirements that
apply under 40 CFR part 86 for model year 2026. Engine must be
certified in separate engine families that qualify for carryover
certification as described in Sec.  1036.235(d).
    (2) The NOX FEL must be at or below 200 mg/hp[middot]hr.
Calculate negative credits as described in Sec.  1036.705 by comparing
the NOX FEL to the FTP emission standard specified in Sec.
1036.104(a)(1), with a value for useful life of 650,000 miles. Meet the
credit reporting and recordkeeping requirements in Sec. Sec.  1036.730
and 1036.735.
    (3) Label the engine as described in 40 CFR 86.095-35, but include
the following alternate compliance statement: ``THIS ENGINE CONFORMS TO
U.S. EPA REGULATIONS FOR MODEL YEAR 2026 ENGINES UNDER 40 CFR
1036.150(k).''
    (l) Credit adjustment for spark-ignition engines and light heavy-
duty compression-ignition engines. For greenhouse gas emission credits
generated from model year 2020 and earlier spark-ignition and light
heavy-duty engines, multiply any banked CO2 credits that you
carry forward to demonstrate compliance with model year 2021 and later
standards by 1.36.
    (m) Infrequent regeneration. For model year 2020 and earlier, you
may invalidate any test interval with respect to CO2
measurements if an infrequent regeneration event occurs during the test
interval. Note that Sec.  1036.580 specifies how to apply infrequent
regeneration adjustment factors for later model years.
    (n) Supplying fuel maps. Engine manufacturers not yet subject to
standards under Sec.  1036.108 in model year 2021 must supply vehicle
manufacturers with fuel maps (or powertrain test results) as described
in Sec.  1036.130 for those engines.
    (o) Engines used in glider vehicles. For purposes of recertifying a
used engine for installation in a glider vehicle, we may allow you to
include in an existing certified engine family those engines you modify
(or otherwise demonstrate) to be identical to engines already covered
by the certificate. We would base such an approval on our review of any
appropriate documentation. These engines must have emission control
information

labels that accurately describe their status.
    (p) Transition to Phase 2 CO2 standards. If you certify all your
model year 2020 engines within an averaging set to the model year 2021
FTP and SET standards and requirements, you may apply the provisions of
this paragraph (p) for enhanced generation and use of emission credits.
These provisions apply separately for Medium HDE and Heavy HDE.
    (1) Greenhouse gas emission credits you 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 Sec.
1036.740(d).
    (2) You may certify your model year 2024 through 2026 engines to
the following alternative standards:

     Table 2 to Paragraph (p)(2) of Sec.   1036.150--Alternative Standards for Model Years 2024 Through 2026
----------------------------------------------------------------------------------------------------------------
                                               Medium heavy-     Heavy heavy-
                 Model years                       duty-            duty-         Medium heavy-    Heavy heavy-
                                                 vocational       vocational     duty- tractor    duty- tractor
----------------------------------------------------------------------------------------------------------------
2024-2026...................................             542              510              467              442
----------------------------------------------------------------------------------------------------------------

    (q) Confirmatory testing of fuel maps defined in Sec.  1036.505(b).
For model years 2021 and later, where the results from Eq. 1036.235-1
for a confirmatory test are at or below 2.0%, we will not replace the
manufacturer's fuel maps.
    (r) Fuel maps for the transition to updated GEM. (1) You may use
fuel maps from model year 2023 and earlier engines for certifying model
year 2024 and later engines using carryover provisions in Sec.
1036.235(d).
    (2) Compliance testing will be based on the GEM version you used to
generate fuel maps for certification. For example, if you perform a
selective enforcement audit with respect to fuel maps, use the same GEM
version that you used to generate fuel maps for certification.
Similarly, we will use the same GEM version that you used to generate
fuel maps for certification if we perform confirmatory testing with one
of your engine families.
    (s) Greenhouse gas compliance testing. Select duty cycles and
measure emissions to demonstrate compliance with greenhouse gas
emission standards before model year 2027 as follows:
    (1) For model years 2016 through 2020, measure emissions using the
FTP duty cycle specified in Sec.  1036.512 and the SET duty cycle
specified in 40 CFR 86.1362, as applicable.
    (2) The following provisions apply for model years 2021 through
2026:
    (i) Determine criteria pollutant emissions during any testing used
to demonstrate compliance with greenhouse gas emission standards;
however, the duty-cycle standards of Sec.  1036.104 apply for measured
criteria pollutant emissions only as described in subpart F of this
part.
    (ii) You may demonstrate compliance with SET-based greenhouse gas
emission standards in Sec.  1036.108(a)(1) using the SET duty cycle
specified in 40 CFR 86.1362 if you collect emissions with continuous
sampling. Integrate the test results by mode to establish separate
emission rates for each mode (including the transition following each
mode, as applicable). Apply the CO2 weighting factors
specified in 40 CFR 86.1362 to calculate a composite emission result.
    (t) Model year 2027 compliance date. The following provisions
describe when this part 1036 starts to apply for model year 2027
engines:
    (1) Split model year. Model year 2027 engines you produce before
December 20, 2026 are subject to the criteria standards and related
provisions in 40 CFR part 86, subpart A, as described in Sec.
1036.1(a). Model year 2027 engines you produce on or after December 20,
2026 are subject to all the provisions of this part.
    (2) Optional early compliance. You may optionally certify model
year 2027 engines you produce before December 20, 2026 to all the
provisions of this part.
    (3) Certification. If you certify any model year 2027 engines to 40
CFR part 86, subpart A, under paragraph (t)(1) of this section, certify
the engine family by dividing the model year into two partial model
years. The first portion of the model year starts when it would
normally start and ends when you no longer produce engines meeting
standards under 40 CFR part 86, subpart A, on or before December 20,
2026. The second portion of the model year starts when you begin
producing engines meeting standards under this part 1036, and ends on
the day your model year would normally end. The following additional
provisions apply for model year 2027 if you split the model year as
described in this paragraph (t):
    (i) You may generate emission credits only with engines that are
certified under this part 1036.
    (ii) In your production report under Sec.  1036.250(a), identify
production volumes separately for the two parts of the model year.
    (iii) OBD testing demonstrations apply singularly for the full
model year.
    (u) Crankcase emissions. The provisions of 40 CFR 86.007-11(c) for
crankcase emissions continue to apply through model year 2026.
    (v) OBD communication protocol. We may approve the alternative
communication protocol specified in SAE J1979-2 (incorporated by
reference in Sec.  1036.810) if the protocol is approved by the
California Air Resources Board. The alternative protocol would apply
instead of SAE J1939 and SAE J1979 as specified in 40 CFR 86.010-
18(k)(1). Engines designed to comply with SAE J1979-2 must meet the
freeze-frame requirements in Sec.  1036.110(b)(8) and in 13 CCR
1971.1(h)(4.3.2) (incorporated by reference in Sec.  1036.810). This
paragraph (v) also applies for model year 2026 and earlier engines.
    (w) Greenhouse gas warranty. For model year 2027 and later engines,
you may ask us to approve the model year 2026 warranty periods
specified in Sec.  1036.120 for components or systems needed to comply
with greenhouse gas emission standards if those components or systems
do not play a role in complying with criteria pollutant standards.
    (x) Powertrain testing for criteria pollutants. You may apply the
powertrain testing provisions of Sec.  1036.101(b) for demonstrating
compliance with criteria pollutant emission standards in 40 CFR part 86
before model year 2027.
    (y) NOX compliance allowance for in-use testing. A NOX
compliance allowance of 15 mg/hp[middot]hr applies for any in-use
testing of Medium HDE and Heavy HDE as described in subpart E of this
part. Add the compliance allowance to the NOX standard that
applies for each duty cycle and for off-cycle testing, with both field
testing and laboratory testing. The NOX compliance allowance
does not apply for the bin 1 off-cycle standard. As an example, for
manufacturer-run field-testing of a

Heavy HDE, add the 15 mg/hp[middot]hr compliance allowance and the 5
mg/hp[middot]hr accuracy margin from Sec.  1036.420 to the 58 mg/
hp[middot]hr[middot]bin 2 off-cycle standard to calculate a 78 mg/
hp[middot]hr NOX standard.
    (z) Alternate family pass criteria for in-use testing. The
following family pass criteria apply for manufacturer-run in-use
testing instead of the pass criteria described in Sec.  1036.425 for
model years 2027 and 2028:
    (1) Start by measuring emissions from five engines using the
procedures described in subpart E of this part and Sec.  1036.530. If
four or five engines comply fully with the off-cycle bin standards, the
engine family passes and you may stop testing.
    (2) If exactly two of the engines tested under paragraph (z)(1) of
this section do not comply fully with the off-cycle bin standards, test
five more engines. If these additional engines all comply fully with
the off-cycle bin standards, the engine family passes and you may stop
testing.
    (3) If three or more engines tested under paragraphs (z)(1) and (2)
of this section do not comply fully with the off-cycle bin standards,
test a total of at least 10 but not more than 15 engines. Calculate the
arithmetic mean of the bin emissions from all the engine tests as
specified in Sec.  1036.530(g) for each pollutant. If the mean values
are at or below the off-cycle bin standards, the engine family passes.
If the mean value for any pollutant is above an off-cycle bin standard,
the engine family fails.

Subpart C--Certifying Engine Families

Sec.  1036.201  General requirements for obtaining a certificate of
conformity.

    (a) You must send us a separate application for a certificate of
conformity for each engine family. A certificate of conformity is valid
from the indicated effective date until December 31 of the model year
for which it is issued.
    (b) The application must contain all the information required by
this part and must not include false or incomplete statements or
information (see Sec.  1036.255).
    (c) We may ask you to include less information than we specify in
this subpart, as long as you maintain all the information required by
Sec.  1036.250.
    (d) You must use good engineering judgment for all decisions
related to your application (see 40 CFR 1068.5).
    (e) An authorized representative of your company must approve and
sign the application.
    (f) See Sec.  1036.255 for provisions describing how we will
process your application.
    (g) We may require you to deliver your test engines to a facility
we designate for our testing (see Sec.  1036.235(c)). Alternatively,
you may choose to deliver another engine that is identical in all
material respects to the test engine, or another engine that we
determine can appropriately serve as an emission-data engine for the
engine family.
    (h) For engines that become new after being placed into service,
such as rebuilt engines installed in new vehicles, we may specify
alternate certification provisions consistent with the intent of this
part. See 40 CFR 1068.120(h) and the definition of ``new motor vehicle
engine'' in Sec.  1036.801.

Sec.  1036.205  Requirements for an application for certification.

    This section specifies the information that must be in your
application, unless we ask you to include less information under Sec.
1036.201(c). We may require you to provide additional information to
evaluate your application.
    (a) Identify the engine family's primary intended service class and
describe how that conforms to the specifications in Sec.  1036.140.
Also, describe the engine family's specifications and other basic
parameters of the engine's design and emission controls with respect to
compliance with the requirements of this part. List the fuel type on
which your engines are designed to operate (for example, gasoline,
diesel fuel, or natural gas). For engines that can operate on multiple
fuels, identify whether they are dual-fuel or flexible-fuel engines;
also identify the range of mixtures for operation on blended fuels, if
applicable. List each engine configuration in the engine family. List
the rated power for each engine configuration.
    (b) Explain how the emission control system operates. Describe in
detail all system components for controlling greenhouse gas and
criteria pollutant emissions, including all auxiliary emission control
devices (AECDs) and all fuel-system components you will install on any
production or test engine. Identify the part number of each component
you describe. For this paragraph (b), treat as separate AECDs any
devices that modulate or activate differently from each other. Include
all the following:
    (1) Give a general overview of the engine, the emission control
strategies, and all AECDs.
    (2) Describe each AECD's general purpose and function.
    (3) Identify the parameters that each AECD senses (including
measuring, estimating, calculating, or empirically deriving the
values). Include engine-based parameters and state whether you simulate
them during testing with the applicable procedures.
    (4) Describe the purpose for sensing each parameter.
    (5) Identify the location of each sensor the AECD uses.
    (6) Identify the threshold values for the sensed parameters that
activate the AECD.
    (7) Describe the parameters that the AECD modulates (controls) in
response to any sensed parameters, including the range of modulation
for each parameter, the relationship between the sensed parameters and
the controlled parameters and how the modulation achieves the AECD's
stated purpose. Use graphs and tables, as necessary.
    (8) Describe each AECD's specific calibration details. This may be
in the form of data tables, graphical representations, or some other
description.
    (9) Describe the hierarchy among the AECDs when multiple AECDs
sense or modulate the same parameter. Describe whether the strategies
interact in a comparative or additive manner and identify which AECD
takes precedence in responding, if applicable.
    (10) Explain the extent to which the AECD is included in the
applicable test procedures specified in subpart F of this part.
    (11) Do the following additional things for AECDs designed to
protect engines or vehicles:
    (i) Identify any engine and vehicle design limits that make
protection necessary and describe any damage that would occur without
the AECD.
    (ii) Describe how each sensed parameter relates to the protected
components' design limits or those operating conditions that cause the
need for protection.
    (iii) Describe the relationship between the design limits/
parameters being protected and the parameters sensed or calculated as
surrogates for those design limits/parameters, if applicable.
    (iv) Describe how the modulation by the AECD prevents engines and
vehicles from exceeding design limits.
    (v) Explain why it is necessary to estimate any parameters instead
of measuring them directly and describe how the AECD calculates the
estimated value, if applicable.
    (vi) Describe how you calibrate the AECD modulation to activate
only during conditions related to the stated need to protect components
and only as needed to sufficiently protect those components in a way
that minimizes the emission impact.

    (c) Explain in detail how the engine diagnostic system works,
describing especially the engine conditions (with the corresponding
diagnostic trouble codes) that cause the malfunction indicator to go
on. You may ask us to approve conditions under which the diagnostic
system disregards trouble codes as described in Sec.  1036.110.
    (d) Describe the engines you selected for testing and the reasons
for selecting them.
    (e) Describe any test equipment and procedures that you used,
including any special or alternate test procedures you used (see Sec.
1036.501).
    (f) Describe how you operated the emission-data engine before
testing, including the duty cycle and the number of engine operating
hours used to stabilize emission levels. Explain why you selected the
method of service accumulation. Describe any scheduled maintenance you
did.
    (g) List the specifications of the test fuel to show that it falls
within the required ranges we specify in 40 CFR part 1065.
    (h) Identify the engine family's useful life.
    (i) Include the warranty statement and maintenance instructions you
will give to the ultimate purchaser of each new engine (see Sec. Sec.
1036.120 and 1036.125).
    (j) Include the emission-related installation instructions you will
provide if someone else installs your engines in their vehicles (see
Sec.  1036.130).
    (k) Describe your emission control information label (see Sec.
1036.135). We may require you to include a copy of the label.
    (l) Identify the duty-cycle emission standards from Sec. Sec.
1036.104(a) and (b) and 1036.108(a) that apply for the engine family.
Also identify FELs and FCLs as follows:
    (1) Identify the NOX FEL over the FTP for the engine
family.
    (2) Identify the CO2 FCLs for the engine family; also
identify any FELs that apply for CH4 and N2O. The
actual U.S.-directed production volume of configurations that have
CO2 emission rates at or below the FCL and CH4
and N2O emission rates at or below the applicable standards
or FELs must be at least one percent of your actual (not projected)
U.S.-directed production volume for the engine family. Identify
configurations within the family that have emission rates at or below
the FCL and meet the one percent requirement. For example, if your
U.S.-directed production volume for the engine family is 10,583 and the
U.S.-directed production volume for the tested rating is 75 engines,
then you can comply with this provision by setting your FCL so that one
more rating with a U.S.-directed production volume of at least 31
engines meets the FCL. Where applicable, also identify other testable
configurations required under Sec.  1036.230(f)(2)(ii).
    (m) Identify the engine family's deterioration factors and describe
how you developed them (see Sec. Sec.  1036.240 and 1036.241). Present
any test data you used for this. For engines designed to discharge
crankcase emissions to the ambient atmosphere, use the deterioration
factors for crankcase emission to determine deteriorated crankcase
emission levels of NOX, HC, PM, and CO as specified in Sec.
1036.240(e).
    (n) State that you operated your emission-data engines as described
in the application (including the test procedures, test parameters, and
test fuels) to show you meet the requirements of this part.
    (o) Present emission data from all valid tests on an emission-data
engine to show that you meet emission standards. Note that Sec.
1036.235 allows you to submit an application in certain cases without
new emission data. Present emission data as follows:
    (1) For hydrocarbons (such as NMHC or NMHCE), NOX, PM,
and CO, as applicable, show your engines meet the applicable exhaust
emission standards we specify in Sec.  1036.104. Show emission figures
for duty-cycle exhaust emission standards before and after applying
adjustment factors for regeneration and deterioration factors for each
engine.
    (2) For CO2, CH4, and N2O, show
that your engines meet the applicable emission standards we specify in
Sec.  1036.108. Show emission figures before and after applying
deterioration factors for each engine. In addition to the composite
results, show individual measurements for cold-start testing and hot-
start testing over the transient test cycle. For each of these tests,
also include the corresponding exhaust emission data for criteria
emissions.
    (3) If we specify more than one grade of any fuel type (for
example, a summer grade and winter grade of gasoline), you need to
submit test data only for one grade, unless the regulations of this
part specify otherwise for your engine.
    (p) State that all the engines in the engine family comply with the
off-cycle emission standards we specify in Sec.  1036.104 for all
normal operation and use when tested as specified in Sec.  1036.530.
Describe any relevant testing, engineering analysis, or other
information in sufficient detail to support your statement. We may
direct you to include emission measurements representing typical engine
in-use operation at a range of ambient conditions. For example, we may
specify certain transient and steady-state engine operation that is
typical for the types of vehicles that use your engines. See Sec.
1036.210.
    (q) We may ask you to send information to confirm that the emission
data you submitted were from valid tests meeting the requirements of
this part and 40 CFR part 1065. You must indicate whether there are
test results from invalid tests or from any other tests of the
emission-data engine, whether or not they were conducted according to
the test procedures of subpart F of this part. We may require you to
report these additional test results.
    (r) Describe all adjustable operating parameters (see Sec.
1036.115(f)), including production tolerances. For any operating
parameters that do not qualify as adjustable parameters, include a
description supporting your conclusion (see 40 CFR 1068.50(c)). Include
the following in your description of each adjustable parameter:
    (1) For practically adjustable operating parameters, include the
nominal or recommended setting, the intended practically adjustable
range, and the limits or stops used to establish adjustable ranges.
State that the limits, stops, or other means of inhibiting adjustment
are effective in preventing adjustment of parameters on in-use engines
to settings outside your intended practically adjustable ranges and
provide information to support this statement.
    (2) For programmable operating parameters, state that you have
restricted access to electronic controls to prevent parameter
adjustment on in-use engines that would allow operation outside the
practically adjustable range. Describe how your engines are designed to
prevent unauthorized adjustments.
    (s) Provide the information to read, record, and interpret all the
information broadcast by an engine's onboard computers and ECMs as
described in Sec.  1036.115(d). State that, upon request, you will give
us any hardware, software, or tools we would need to do this.
    (t) State whether your certification is limited for certain
engines. For example, you might certify engines only for use in
tractors, in emergency vehicles, or in vehicles with hybrid
powertrains. If this is the case, describe how you will prevent use of
these engines in vehicles for which they are not certified.
    (u) Unconditionally certify that all the engines in the engine
family comply with the requirements of this part, other referenced
parts of the CFR, and the

Clean Air Act. Note that Sec.  1036.235 specifies which engines to test
to show that engines in the entire family comply with the requirements
of this part.
    (v) Include good-faith estimates of nationwide production volumes.
Include a justification for the estimated production volumes if they
are substantially different than actual production volumes in earlier
years for similar models.
    (w) Include the information required by other subparts of this
part. For example, include the information required by Sec.  1036.725
if you participate in the ABT program.
    (x) Include other applicable information, such as information
specified in this part or 40 CFR part 1068 related to requests for
exemptions.
    (y) Name an agent for service located in the United States. Service
on this agent constitutes service on you or any of your officers or
employees for any action by EPA or otherwise by the United States
related to the requirements of this part.
    (z) For imported engines, identify the following:
    (1) Describe your normal practice for importing engines. For
example, this may include identifying the names and addresses of anyone
you have authorized to import your engines. Engines imported by
nonauthorized agents are not covered by your certificate.
    (2) The location of a test facility in the United States where you
can test your engines if we select them for testing under a selective
enforcement audit, as specified in 40 CFR part 1068, subpart E.
    (aa) Include information needed to certify vehicles to greenhouse
gas standards under 40 CFR part 1037 as described in Sec.  1036.505.

Sec.  1036.210  Preliminary approval before certification.

    If you send us information before you finish the application, we
may review it and make any appropriate determinations, especially for
questions related to engine family definitions, auxiliary emission
control devices, adjustable parameters, deterioration factors, testing
for service accumulation, and maintenance. Decisions made under this
section are considered to be preliminary approval, subject to final
review and approval. We will generally not reverse a decision where we
have given you preliminary approval, unless we find new information
supporting a different decision. If you request preliminary approval
related to the upcoming model year or the model year after that, we
will make best-efforts to make the appropriate determinations as soon
as practicable. We will generally not provide preliminary approval
related to a future model year more than two years ahead of time.

Sec.  1036.225  Amending applications for certification.

    Before we issue you a certificate of conformity, you may amend your
application to include new or modified engine configurations, subject
to the provisions of this section. After we have issued your
certificate of conformity, you may send us an amended application any
time before the end of the model year requesting that we include new or
modified engine configurations within the scope of the certificate,
subject to the provisions of this section. You must also amend your
application if any changes occur with respect to any information that
is included or should be included in your application.
    (a) You must amend your application before you take any of the
following actions:
    (1) Add an engine configuration to an engine family. In this case,
the engine configuration added must be consistent with other engine
configurations in the engine family with respect to the design aspects
listed in Sec.  1036.230.
    (2) Change an engine configuration already included in an engine
family in a way that may affect emissions, or change any of the
components you described in your application for certification. This
includes production and design changes that may affect emissions any
time during the engine's lifetime.
    (3) Modify an FEL or FCL for an engine family as described in
paragraph (f) of this section.
    (b) To amend your application for certification, send the relevant
information to the Designated Compliance Officer.
    (1) Describe in detail the addition or change in the engine model
or configuration you intend to make.
    (2) Include engineering evaluations or data showing that the
amended engine family complies with all applicable requirements. You
may do this by showing that the original emission-data engine is still
appropriate for showing that the amended family complies with all
applicable requirements.
    (3) If the original emission-data engine for the engine family is
not appropriate to show compliance for the new or modified engine
configuration, include new test data showing that the new or modified
engine configuration meets the requirements of this part.
    (4) Include any other information needed to make your application
correct and complete.
    (c) We may ask for more test data or engineering evaluations. You
must give us these within 30 days after we request them.
    (d) For engine families already covered by a certificate of
conformity, we will determine whether the existing certificate of
conformity covers your newly added or modified engine. You may ask for
a hearing if we deny your request (see Sec.  1036.820).
    (e) The amended application applies starting with the date you
submit the amended application, as follows:
    (1) For engine families already covered by a certificate of
conformity, you may start producing a new or modified engine
configuration any time after you send us your amended application and
before we make a decision under paragraph (d) of this section. However,
if we determine that the affected engines do not meet applicable
requirements in this part, we will notify you to cease production of
the engines and may require you to recall the engines at no expense to
the owner. Choosing to produce engines under this paragraph (e) is
deemed to be consent to recall all engines that we determine do not
meet applicable emission standards or other requirements in this part
and to remedy the nonconformity at no expense to the owner. If you do
not provide information required under paragraph (c) of this section
within 30 days after we request it, you must stop producing the new or
modified engines.
    (2) [Reserved]
    (f) You may ask us to approve a change to your FEL in certain cases
after the start of production, but before the end of the model year. If
you change an FEL for CO2, your FCL for CO2 is
automatically set to your new FEL divided by 1.03. The changed FEL may
not apply to engines you have already introduced into U.S. commerce,
except as described in this paragraph (f). You may ask us to approve a
change to your FEL in the following cases:
    (1) You may ask to raise your FEL for your engine family at any
time. In your request, you must show that you will still be able to
meet the emission standards as specified in subparts B and H of this
part. Use the appropriate FELs/FCLs with corresponding production
volumes to calculate emission credits for the model year, as described
in subpart H of this part.
    (2) You may ask to lower the FEL for your engine family only if you
have test data from production engines showing that emissions are below
the proposed

lower FEL (or below the proposed FCL for CO2). The lower
FEL/FCL applies only to engines you produce after we approve the new
FEL/FCL. Use the appropriate FEL/FCL with corresponding production
volumes to calculate emission credits for the model year, as described
in subpart H of this part.
    (g) You may produce engines or modify in-use engines as described
in your amended application for certification and consider those
engines to be in a certified configuration. Modifying a new or in-use
engine to be in a certified configuration does not violate the
tampering prohibition of 40 CFR 1068.101(b)(1), as long as this does
not involve changing to a certified configuration with a higher family
emission limit.

Sec.  1036.230  Selecting engine families.

    (a) For purposes of certification to the standards of this part,
divide your product line into families of engines that are expected to
have similar characteristics for criteria emissions throughout the
useful life as described in this section. Your engine family is limited
to a single model year.
    (b) Group engines in the same engine family if they are the same in
all the following design aspects:
    (1) The combustion cycle and fuel. See paragraph (g) of this
section for special provisions that apply for dual-fuel and flexible-
fuel engines.
    (2) The cooling system (water-cooled vs. air-cooled).
    (3) Method of air aspiration, including the location of intake and
exhaust valves or ports and the method of intake-air cooling, if
applicable.
    (4) The arrangement and composition of catalytic converters and
other aftertreatment devices.
    (5) Cylinder arrangement (such as in-line vs. vee configurations)
and bore center-to-center dimensions.
    (6) Method of control for engine operation other than governing
(i.e., mechanical or electronic).
    (7) The numerical level of the applicable criteria emission
standards. For example, an engine family may not include engines
certified to different family emission limits for criteria emission
standards, though you may change family emission limits without
recertifying as specified in Sec.  1036.225(f).
    (c) You may subdivide a group of engines that is identical under
paragraph (b) of this section into different engine families if you
show the expected criteria emission characteristics are different
during the useful life.
    (d) In unusual circumstances, you may group engines that are not
identical with respect to the design aspects listed in paragraph (b) of
this section in the same engine family if you show that their criteria
emission characteristics during the useful life will be similar.
    (e) Engine configurations certified as hybrid engines or hybrid
powertrains may not be included in an engine family with engines that
have nonhybrid powertrains. Note that this does not prevent you from
including engines in a nonhybrid family if they are used in hybrid
vehicles, as long as you certify them based on engine testing.
    (f) You must certify your engines to the greenhouse gas standards
of Sec.  1036.108 using the same engine families you use for criteria
pollutants. The following additional provisions apply with respect to
demonstrating compliance with the standards in Sec.  1036.108:
    (1) You may subdivide an engine family into subfamilies that have a
different FCL for CO2 emissions. These subfamilies do not
apply for demonstrating compliance with criteria standards in Sec.
1036.104.
    (2) If you certify engines in the family for use as both vocational
and tractor engines, you must split your family into two separate
subfamilies.
    (i) Calculate emission credits relative to the vocational engine
standard for the number of engines sold into vocational applications
and relative to the tractor engine standard for the number of engines
sold into non-vocational tractor applications. You may assign the
numbers and configurations of engines within the respective subfamilies
at any time before submitting the report required by Sec.  1036.730. If
the family participates in averaging, banking, or trading, you must
identify the type of vehicle in which each engine is installed; we may
alternatively allow you to use statistical methods to determine this
for a fraction of your engines. Keep records to document this
determination.
    (ii) If you restrict use of the test configuration for your split
family only to tractors, or only to vocational vehicles, you must
identify a second testable configuration for the other type of vehicle
(or an unrestricted configuration). Identify this configuration in your
application for certification. The FCL for the engine family applies
for this configuration as well as the primary test configuration.
    (3) If you certify both engine fuel maps and powertrain fuel maps
for an engine family, you may split the engine family into two separate
subfamilies. Indicate this in your application for certification, and
identify whether one or both of these sets of fuel maps applies for
each group of engines. If you do not split your family, all engines
within the family must conform to the engine fuel maps, including any
engines for with the powertrain maps also apply.
    (4) If you certify in separate engine families engines that could
have been certified in vocational and tractor engine subfamilies in the
same engine family, count the two families as one family for purposes
of determining your obligations with respect to the OBD requirements
and in-use testing requirements. Indicate in the applications for
certification that the two engine families are covered by this
paragraph (f)(4).
    (5) Except as described in this paragraph (f), engine
configurations within an engine family must use equivalent greenhouse
gas emission controls. Unless we approve it, you may not produce
nontested configurations without the same emission control hardware
included on the tested configuration. We will only approve it if you
demonstrate that the exclusion of the hardware does not increase
greenhouse gas emissions.
    (g) You may certify dual-fuel or flexible-fuel engines in a single
engine family. You may include dedicated-fuel versions of this same
engine model in the same engine family, as long as they are identical
to the engine configuration with respect to that fuel type for the
dual-fuel or flexible-fuel version of the engine. For example, if you
produce an engine that can alternately run on gasoline and natural gas,
you can include the gasoline-only and natural gas-only versions of the
engine in the same engine family as the dual-fuel engine if engine
operation on each fuel type is identical with or without installation
of components for operating on the other fuel.

Sec.  1036.235  Testing requirements for certification.

    This section describes the emission testing you must perform to
show compliance with the emission standards in Sec. Sec.  1036.104 and
1036.108.
    (a) Select and configure one or two emission-data engines from each
engine family as follows:
    (1) You may use one engine for criteria pollutant testing and a
different engine for greenhouse gas emission testing, or you may use
the same engine for all testing.
    (2) For criteria pollutant emission testing, select the engine
configuration with the highest volume of fuel injected per cylinder per
combustion cycle at the point of maximum torque--unless good

engineering judgment indicates that a different engine configuration is
more likely to exceed (or have emissions nearer to) an applicable
emission standard or FEL. If two or more engines have the same fueling
rate at maximum torque, select the one with the highest fueling rate at
rated speed. In making this selection, consider all factors expected to
affect emission-control performance and compliance with the standards,
including emission levels of all exhaust constituents, especially
NOX and PM. To the extent we allow it for establishing
deterioration factors, select for testing those engine components or
subsystems whose deterioration best represents the deterioration of in-
use engines.
    (3) For greenhouse gas emission testing, the standards of this part
apply only with respect to emissions measured from the tested
configuration and other configurations identified in Sec.
1036.205(l)(2). Note that configurations identified in Sec.
1036.205(l)(2) are considered to be ``tested configurations'' whether
or not you test them for certification. However, you must apply the
same (or equivalent) emission controls to all other engine
configurations in the engine family. In other contexts, the tested
configuration is sometimes referred to as the ``parent configuration'',
although the terms are not synonymous.
    (b) Test your emission-data engines using the procedures and
equipment specified in subpart F of this part. In the case of dual-fuel
and flexible-fuel engines, measure emissions when operating with each
type of fuel for which you intend to certify the engine.
    (1) For criteria pollutant emission testing, measure
NOX, PM, CO, and NMHC emissions using each duty cycle
specified in Sec.  1036.104.
    (2) For greenhouse gas emission testing, measure CO2,
CH4, and N2O emissions; the following provisions
apply regarding test cycles for demonstrating compliance with tractor
and vocational standards:
    (i) If you are certifying the engine for use in tractors, you must
measure CO2 emissions using the SET duty cycle specified in
Sec.  1036.510, taking into account the interim provisions in Sec.
1036.150(s), and measure CH4 and N2O emissions
using the FTP transient cycle.
    (ii) If you are certifying the engine for use in vocational
applications, you must measure CO2, CH4, and
N2O emissions using the appropriate FTP transient duty
cycle, including cold-start and hot-start testing as specified in Sec.
1036.512.
    (iii) You may certify your engine family for both tractor and
vocational use by submitting CO2 emission data and
specifying FCLs for both SET and FTP transient duty cycles.
    (iv) Some of your engines certified for use in tractors may also be
used in vocational vehicles, and some of your engines certified for use
in vocational may be used in tractors. However, you may not knowingly
circumvent the intent of this part (to reduce in-use emissions of
CO2) by certifying engines designed for tractors or
vocational vehicles (and rarely used in the other application) to the
wrong cycle. For example, we would generally not allow you to certify
all your engines to the SET duty cycle without certifying any to the
FTP transient cycle.
    (c) We may perform confirmatory testing by measuring emissions from
any of your emission-data engines. If your certification includes
powertrain testing as specified in Sec.  1036.630, this paragraph (c)
also applies for the powertrain test results.
    (1) We may decide to do the testing at your plant or any other
facility. If we do this, you must deliver the engine to a test facility
we designate. The engine you provide must include appropriate
manifolds, aftertreatment devices, ECMs, and other emission-related
components not normally attached directly to the engine block. If we do
the testing at your plant, you must schedule it as soon as possible and
make available the instruments, personnel, and equipment we need.
    (2) If we measure emissions on your engine, the results of that
testing become the official emission results for the engine as
specified in this paragraph (c). Unless we later invalidate these data,
we may decide not to consider your data in determining if your engine
family meets applicable requirements in this part.
    (3) Before we test one of your engines, we may set its adjustable
parameters to any point within the practically adjustable ranges (see
Sec.  1036.115(f)).
    (4) Before we test one of your engines, we may calibrate it within
normal production tolerances for anything we do not consider an
adjustable parameter. For example, we may calibrate it within normal
production tolerances for an engine parameter that is subject to
production variability because it is adjustable during production, but
is not considered an adjustable parameter because it is permanently
sealed. For parameters that relate to a level of performance that is
itself subject to a specified range (such as maximum power output), we
will generally perform any calibration under this paragraph (c)(4) in a
way that keeps performance within the specified range.
    (5) For greenhouse gas emission testing, we may use our emission
test results for steady-state, idle, cycle-average and powertrain fuel
maps defined in Sec.  1036.505(b) as the official emission results. We
will not replace individual points from your fuel map.
    (i) We will determine fuel masses, mfuel[cycle], and
mean idle fuel mass flow rates, mifuelidle, if applicable,
using both direct and indirect measurement. We will determine the
result for each test point based on carbon balance error verification
as described in Sec.  1036.535(g)(3)(i) and (ii).
    (ii) We will perform this comparison using the weighted results
from GEM, using vehicles that are appropriate for the engine under
test. For example, we may select vehicles that the engine went into for
the previous model year.
    (iii) If you supply cycle-average engine fuel maps for the highway
cruise cycles instead of generating a steady-state fuel map for these
cycles, we may perform a confirmatory test of your engine fuel maps for
the highway cruise cycles by either of the following methods:
    (A) Directly measuring the highway cruise cycle-average fuel maps.
    (B) Measuring a steady-state fuel map as described in this
paragraph (c)(5) and using it in GEM to create our own cycle-average
engine fuel maps for the highway cruise cycles.
    (iv) We will replace fuel maps as a result of confirmatory testing
as follows:
    (A) Weight individual duty cycle results using the vehicle
categories determined in paragraph (c)(5)(i) of this section and
respective weighting factors in 40 CFR 1037.510(c) to determine a
composite CO2 emission value for each vehicle configuration;
then repeat the process for all the unique vehicle configurations used
to generate the manufacturer's fuel maps.
    (B) The average percent difference between fuel maps is calculated
using the following equation:

[GRAPHIC] [TIFF OMITTED] TR24JA23.013

Where:

i = an indexing variable that represents one individual weighted
duty cycle result for a vehicle configuration.
N = total number of vehicle configurations.
eCO2compEPAi = unrounded composite mass of CO2
emissions in g/ton-mile for vehicle configuration i for the EPA
test.
eCO2compManui = unrounded composite mass of
CO2 emissions in g/ton-mile for vehicle configuration i
for the manufacturer-declared map.

    (C) Where the unrounded average percent difference between our
composite weighted fuel map and the manufacturer's is at or below 0%,
we will not replace the manufacturer's maps, and we will consider an
individual engine to have passed the fuel map.
    (6) We may perform confirmatory testing with an engine dynamometer
to simulate normal engine operation to determine whether your emission-
data engine meets off-cycle emission standards. The accuracy margins
described in Sec.  1036.420(a) do not apply for such laboratory
testing.
    (d) You may ask to use carryover emission data from a previous
model year instead of doing new tests, but only if all the following
are true:
    (1) The engine family from the previous model year differs from the
current engine family only with respect to model year, items identified
in Sec.  1036.225(a), or other characteristics unrelated to emissions.
We may waive this criterion for differences we determine not to be
relevant.
    (2) The emission-data engine from the previous model year remains
the appropriate emission-data engine under paragraph (a) of this
section.
    (3) The data show that the emission-data engine would meet all the
requirements that apply to the engine family covered by the application
for certification.
    (e) We may require you to test a second engine of the same
configuration in addition to the engines tested under paragraph (a) of
this section.
    (f) If you use an alternate test procedure under 40 CFR 1065.10 and
later testing shows that such testing does not produce results that are
equivalent to the procedures specified in subpart F of this part, we
may reject data you generated using the alternate procedure.
    (g) We may evaluate or test your engines to determine whether they
have a defeat device before or after we issue a certificate of
conformity. We may test or require testing on any vehicle or engine at
a designated location, using driving cycles and conditions that may
reasonably be expected in normal operation and use to investigate a
potential defeat device. If we designate an engine's AECD as a possible
defeat device, you must demonstrate to us that that the AECD does not
reduce emission control effectiveness when the engine operates under
conditions that may reasonably be expected in normal operation and use,
unless one of the specific exceptions described in Sec.  1036.115(h)
applies.

Sec.  1036.240  Demonstrating compliance with criteria pollutant
emission standards.

    (a) For purposes of certification, your engine family is considered
in compliance with the duty-cycle emission standards in Sec.
1036.104(a)(1) and (2) if all emission-data engines representing that
family have test results showing official emission results and
deteriorated emission levels at or below these standards (including all
corrections and adjustments). This also applies for all test points for
emission-data engines within the family used to establish deterioration
factors. Note that your FELs are considered to be the applicable
emission standards with which you must comply if you participate in the
ABT program in subpart H of this part. Use good engineering judgment to
demonstrate compliance with off-cycle standards throughout the useful
life.
    (b) Your engine family is deemed not to comply if any emission-data
engine representing that family has test results showing an official
emission result or a deteriorated emission level for any pollutant that
is above an applicable emission standard (including all corrections and
adjustments). Similarly, your engine family is deemed not to comply if
any emission-data engine representing that family has test results
showing any emission level above the applicable off-cycle emission
standard for any pollutant. This also applies for all test points for
emission-data engines within the family used to establish deterioration
factors.
    (c) To compare emission levels from the emission-data engine with
the applicable duty-cycle emission standards, apply deterioration
factors to the measured emission levels for each pollutant. Section
1036.245 specifies how to test engines and engine components to develop
deterioration factors that represent the deterioration expected in
emissions over your engines' useful life. Section 1036.246 describes
how to confirm or modify deterioration factors based on in-use
verification testing. Your deterioration factors must take into account
any available data from other in-use testing with similar engines.
Small manufacturers may use assigned deterioration factors that we
establish. Apply deterioration factors as follows:
    (1) Additive deterioration factor for exhaust emissions. Except as
specified in paragraph (c)(2) of this section, use an additive
deterioration factor for exhaust emissions. An additive deterioration
factor is the difference between exhaust emissions at the end of the
useful life and exhaust emissions at the low-hour test point. In these
cases, adjust the official emission results for each tested engine at
the selected test point by adding the factor to the measured emissions.
If the factor is less than zero, use zero. Additive deterioration
factors must be specified to one more decimal place than the applicable
standard.
    (2) Multiplicative deterioration factor for exhaust emissions. Use
a multiplicative deterioration factor if good engineering judgment
calls for the deterioration factor for a pollutant to be the ratio of
exhaust emissions at the end of the useful life to exhaust emissions at
the low-hour test point. For example, if you use aftertreatment
technology that controls emissions of a pollutant proportionally to
engine-out emissions, it is often appropriate to use a multiplicative
deterioration factor. Adjust the official emission results for each
tested engine at the selected test point by multiplying the measured
emissions by the deterioration factor. If the factor is less than one,
use one. A multiplicative deterioration factor may not be appropriate
in cases where testing variability is significantly greater than
engine-to-engine variability. Multiplicative deterioration factors must

be specified to one more significant figure than the applicable
standard.
    (3) Sawtooth and other nonlinear deterioration patterns. The
deterioration factors described in paragraphs (c)(1) and (2) of this
section assume that the highest useful life emissions occur either at
the end of useful life or at the low-hour test point. The provisions of
this paragraph (c)(3) apply where good engineering judgment indicates
that the highest useful life emissions will occur between these two
points. For example, emissions may increase with service accumulation
until a certain maintenance step is performed, then return to the low-
hour emission levels and begin increasing again. Such a pattern may
occur with battery-based electric hybrid engines. Base deterioration
factors for engines with such emission patterns on the difference
between (or ratio of) the point at which the highest emissions occur
and the low-hour test point. Note that this applies for maintenance-
related deterioration only where we allow such critical emission-
related maintenance.
    (4) Dual-fuel and flexible-fuel engines. In the case of dual-fuel
and flexible-fuel engines, apply deterioration factors separately for
each fuel type. You may accumulate service hours on a single emission-
data engine using the type of fuel or the fuel mixture expected to have
the highest combustion and exhaust temperatures; you may ask us to
approve a different fuel mixture if you demonstrate that a different
criterion is more appropriate.
    (5) Deterioration factor for crankcase emissions. If engines route
crankcase emissions into the ambient atmosphere or into the exhaust
downstream of exhaust aftertreatment, you must account for any increase
in crankcase emissions throughout the useful life using good
engineering judgment. Use separate deterioration factors for crankcase
emissions of each pollutant (either multiplicative or additive).
    (d) Determine the official emission result for each pollutant to at
least one more decimal place than the applicable standard. Apply the
deterioration factor to the official emission result, as described in
paragraph (c) of this section, then round the adjusted figure to the
same number of decimal places as the emission standard. Compare the
rounded emission levels to the emission standard for each emission-data
engine.
    (e) You do not need deterioration factors to demonstrate compliance
with off-cycle standards. However, for engines designed to discharge
crankcase emissions to the ambient atmosphere, you must determine
deteriorated emission levels to represent crankcase emissions at the
end of useful life for purposes of demonstrating compliance with off-
cycle emission standards. Determine an official brake-specific
crankcase emission result for each pollutant based on operation over
the FTP duty cycle. Also determine an official crankcase emission
result for NOX in g/hr from the idle portion of any of the
duty cycles specified in subpart F of this part. Apply crankcase
deterioration factors to all these official crankcase emission results
as described in paragraph (c) of this section, then round the adjusted
figures to the same number of decimal places as the off-cycle emission
standards in Sec.  1036.104(a)(3).

Sec.  1036.241  Demonstrating compliance with greenhouse gas emission
standards.

    (a) For purposes of certification, your engine family is considered
in compliance with the emission standards in Sec.  1036.108 if all
emission-data engines representing the tested configuration of that
engine family have test results showing official emission results and
deteriorated emission levels at or below the standards. Note that your
FCLs are considered to be the applicable emission standards with which
you must comply for certification.
    (b) Your engine family is deemed not to comply if any emission-data
engine representing the tested configuration of that engine family has
test results showing an official emission result or a deteriorated
emission level for any pollutant that is above an applicable emission
standard (generally the FCL). Note that you may increase your FCL if
any certification test results exceed your initial FCL.
    (c) Apply deterioration factors to the measured emission levels for
each pollutant to show compliance with the applicable emission
standards. Your deterioration factors must take into account any
available data from in-use testing with similar engines. Apply
deterioration factors as follows:
    (1) Additive deterioration factor for greenhouse gas emissions.
Except as specified in paragraphs (c)(2) and (3) of this section, use
an additive deterioration factor for exhaust emissions. An additive
deterioration factor is the difference between the highest exhaust
emissions (typically at the end of the useful life) and exhaust
emissions at the low-hour test point. In these cases, adjust the
official emission results for each tested engine at the selected test
point by adding the factor to the measured emissions. If the factor is
less than zero, use zero. Additive deterioration factors must be
specified to one more decimal place than the applicable standard.
    (2) Multiplicative deterioration factor for greenhouse gas
emissions. Use a multiplicative deterioration factor for a pollutant if
good engineering judgment calls for the deterioration factor for that
pollutant to be the ratio of the highest exhaust emissions (typically
at the end of the useful life) to exhaust emissions at the low-hour
test point. Adjust the official emission results for each tested engine
at the selected test point by multiplying the measured emissions by the
deterioration factor. If the factor is less than one, use one. A
multiplicative deterioration factor may not be appropriate in cases
where testing variability is significantly greater than engine-to-
engine variability. Multiplicative deterioration factors must be
specified to one more significant figure than the applicable standard.
    (3) Sawtooth and other nonlinear deterioration patterns. The
deterioration factors described in paragraphs (c)(1) and (2) of this
section assume that the highest useful life emissions occur either at
the end of useful life or at the low-hour test point. The provisions of
this paragraph (c)(3) apply where good engineering judgment indicates
that the highest useful life emissions will occur between these two
points. For example, emissions may increase with service accumulation
until a certain maintenance step is performed, then return to the low-
hour emission levels and begin increasing again. Such a pattern may
occur with battery-based electric hybrid engines. Base deterioration
factors for engines with such emission patterns on the difference
between (or ratio of) the point at which the highest emissions occur
and the low-hour test point. Note that this applies for maintenance-
related deterioration only where we allow such critical emission-
related maintenance.
    (4) Dual-fuel and flexible-fuel engines. In the case of dual-fuel
and flexible-fuel engines, apply deterioration factors separately for
each fuel type by measuring emissions with each fuel type at each test
point. You may accumulate service hours on a single emission-data
engine using the type of fuel or the fuel mixture expected to have the
highest combustion and exhaust temperatures; you may ask us to approve
a different fuel mixture if you demonstrate that a different criterion
is more appropriate.
    (d) Calculate emission data using measurements to at least one more
decimal place than the applicable standard. Apply the deterioration
factor to the official emission result, as described in paragraph (c)
of this

section, then round the adjusted figure to the same number of decimal
places as the emission standard. Compare the rounded emission levels to
the emission standard for each emission-data engine.
    (e) If you identify more than one configuration in Sec.
1036.205(l)(2), we may test (or require you to test) any of the
identified configurations. We may also require you to provide an
engineering analysis that demonstrates that untested configurations
listed in Sec.  1036.205(l)(2) comply with their FCL.

Sec.  1036.245  Deterioration factors for exhaust emission standards.

    This section describes how to determine deterioration factors,
either with pre-existing test data or with new emission measurements.
Apply these deterioration factors to determine whether your engines
will meet the duty-cycle emission standards throughout the useful life
as described in Sec.  1036.240. The provisions of this section and the
verification provisions of Sec.  1036.246 apply for all engine families
starting in model year 2027; you may optionally use these provisions to
determine and verify deterioration factors for earlier model years.
    (a) You may ask us to approve deterioration factors for an engine
family based on an engineering analysis of emission measurements from
similar highway or nonroad engines if you have already given us these
data for certifying the other engines in the same or earlier model
years. Use good engineering judgment to decide whether the two engines
are similar. We will approve your request if you show us that the
emission measurements from other engines reasonably represent in-use
deterioration for the engine family for which you have not yet
determined deterioration factors.
    (b) [Reserved]
    (c) If you are unable to determine deterioration factors for an
engine family under paragraph (a) of this section, select engines,
subsystems, or components for testing. Determine deterioration factors
based on service accumulation and related testing to represent the
deterioration expected from in-use engines over the useful life,
including crankcase emissions. You may perform maintenance on emission-
data engines as described in Sec.  1036.125 and 40 CFR part 1065,
subpart E. Use good engineering judgment for all aspects of the effort
to establish deterioration factors under this paragraph (c). Send us
your test plan for our preliminary approval under Sec.  1036.210. You
may apply deterioration factors based on testing under this paragraph
(c) to multiple engine families, consistent with the provisions in
paragraph (a) of this section. Determine deterioration factors based on
a combination of minimum required engine dynamometer aging hours and
accelerated bench-aged aftertreatment as follows:
    (1) Select an emission-data engine and aftertreatment devices and
systems that can be assembled into a certified configuration to
represent the engine family. Stabilize the engine and aftertreatment
devices and systems, together or separately, to prepare for emission
measurements. Perform low-hour emission measurement once the engine has
operated with aftertreatment long enough to stabilize the emission
control. Measure emissions of all regulated pollutants while the engine
operates over all applicable duty cycles on an engine dynamometer as
described in subpart F of this part.
    (2) Perform additional service accumulation as described in
paragraph (c)(3) of this section on an engine dynamometer meeting at
least the following minimum specifications:

 Table 1 to Paragraph (c)(2) of Sec.   1036.245--Minimum Required Engine
        Dynamometer Aging Hours by Primary Intended Service Class
------------------------------------------------------------------------
                                                          Minimum engine
             Primary intended service class                 dynamometer
                                                               hours
------------------------------------------------------------------------
Spark-ignition HDE......................................             300
Light HDE...............................................           1,250
Medium HDE..............................................           1,500
Heavy HDE...............................................           1,500
------------------------------------------------------------------------

    (3) Perform service accumulation in the laboratory by operating the
engine repeatedly over one of the following test sequences, or a
different test sequence that we approve in advance:
    (i) Use duty-cycle sequence 1 for operating any engine on an engine
dynamometer, as follows:
    (A) Operate at idle for 2 hours.
    (B) Operate for 105  1 hours over a repeat sequence of
one FTP followed by one RMC.
    (C) Operate over one LLC.
    (D) Operate at idle for 2 hours.
    (E) Shut down the engine for cooldown to ambient temperature.
    (ii) Duty-cycle sequence 2 is based on operating over the LLC and
the vehicle-based duty cycles from 40 CFR part 1037. Select the vehicle
subcategory and vehicle configuration from Sec.  1036.540 with the
highest reference cycle work for each vehicle-based duty cycle. Operate
the engine as follows for duty-cycle sequence 2:
    (A) Operate at idle for 2 hours.
    (B) Operate for 105  1 hours over a repeat sequence of
one Heavy-duty Transient Test Cycle, then one 55 mi/hr highway cruise
cycle, and then one 65 mi/hr highway cruise cycle.
    (C) Operate over one LLC.
    (D) Operate at idle for 2 hours.
    (E) Shut down the engine for cooldown to ambient temperature.
    (4) Perform all the emission measurements described in paragraph
(c)(1) of this section when the engine has reached the minimum service
accumulation specified in paragraph (c)(2) of this section, and again
after you finish service accumulation in the laboratory if your service
accumulation exceeds the values specified in paragraph (c)(2) of this
section.
    (5) Determine the deterioration factor based on a combination of
actual and simulated service accumulation represented by a number of
hours of engine operation calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.014

Where:

UL = useful life mileage from Sec.  1036.104(e).
k = 1.15 for Heavy HDE and 1.0 for all other primary intended
service classes.
vagingcycle = average speed of aging cycle in paragraph
(c)(3) of this section. Use 40.26 mi/hr for duty-cycle sequence 1
and 44.48 mi/hr for duty-cycle sequence 2.

Example for Heavy HDE for Duty-Cycle Sequence 1:

UL = 650,000 miles
k = 1.15
vagingcycle = 40.26 mi/hr
[GRAPHIC] [TIFF OMITTED] TR24JA23.015

ttotal = 18,567 hr

    (6) Perform accelerated bench aging of aftertreatment devices to
represent normal engine operation over the useful life using the
service accumulation hours determined in paragraph (c)(5) of this
section. Design your bench aging to represent 10,000 hours of in-use
engine operation for every 1,000 hours of accelerated bench aging. Use
the accelerated bench-aging procedure in 40 CFR 1065.1131 through
1065.1145 or get our advance approval to use a different procedure that
adequately that accounts for thermal and chemical degradation. For
example, this might involve testing consistent with the analogous
procedures that apply for light-duty vehicles under 40 CFR part 86,
subpart S.

    (7) After bench-aging aftertreatment devices, install or reinstall
those aftertreatment devices and systems on an emission-data engine (or
an equivalent engine) that has been stabilized without aftertreatment.
Ensure that the aftertreatment is installed such that the engine is in
a certified configuration to represent the engine family.
    (8) Operate the engine with the bench-aged aftertreatment devices
to stabilize emission controls for at least 100 hours on an engine
dynamometer.
    (9) Once stabilization is complete, repeat the low-hour emission
measurements.
    (10) Calculate deterioration factors by comparing exhaust emissions
with the bench-aged aftertreatment and exhaust emissions at the low-
hour test point. Create a linear curve fit if testing includes
intermediate test points. Calculate deterioration factors based on
measured values, without extrapolation.
    (d) If you determine deterioration factors as described in
paragraph (c) of this section, you may apply those deterioration
factors in later years for engine families that qualify for carryover
certification as described in Sec.  1036.235(d). You may also apply
those deterioration factors for additional engine families as described
in paragraph (a) of this section.
    (e) Include the following information in your application for
certification:
    (1) If you use test data from a different engine family, explain
why this is appropriate and include all the emission measurements on
which you base the deterioration factors. If the deterioration factors
for the new engine family are not identical to the deterioration
factors for the different engine family, describe your engineering
analysis to justify the revised values and state that all your data,
analyses, evaluations, and other information are available for our
review upon request.
    (2) If you determined deterioration factors under paragraph (c) of
this section, include the following information in the first year that
you use those deterioration factors:
    (i) Describe your accelerated bench aging or other procedures to
represent full-life service accumulation for the engine's emission
controls.
    (ii) Describe how you prepared the test engine before and after
installing aftertreatment systems to determine deterioration factors.
    (iii) Identify the power rating of the emission-data engine used to
determine deterioration factors.

Sec.  1036.246  Verifying deterioration factors.

    We may require you to test in-use engines as described in this
section to verify that the deterioration factors you determined under
Sec.  1036.245 are appropriate.
    (a) Select and prepare in-use engines representing the engine
family we identify for verification testing under this section as
follows:
    (1) You may recruit candidate engines any time before testing. This
may involve creating a pool of candidate engines and vehicles in
coordination with vehicle manufacturers and vehicle purchasers to
ensure availability and to confirm a history of proper maintenance. You
may meet the testing requirements of this section by repeating tests on
a given engine as it ages, or you may test different engines over the
course of verification testing; however, you may not choose whether to
repeat tests on a given engine at a later stage based on its measured
emission levels. We generally require that you describe your plan for
selecting engines in advance and justify any departures from that plan.
    (2) Selected vehicles must come from independent sources, unless we
approve your request to select vehicles that you own or manage. In your
request, you must describe how you will ensure that the vehicle
operator will drive in a way that represents normal in-use operation
for the engine family.
    (3) Select vehicles with installed engines from the same engine
family and with the same power rating as the emission-data engine used
to determine the deterioration factors. However, if the test engine
does not have the specified power rating, you may ask for our approval
to either test in the as-received condition or modify engines in
selected vehicles by reflashing the ECM or replacing parts to change
the engines to be in a different certified configuration for proper
testing.
    (4) Selected engines must meet the screening criteria described in
Sec.  1036.410(b)(2) through (4). Selected engines must also have their
original aftertreatment components and be in a certified configuration.
You may ask us to approve replacing a critical emission-related
component with an equivalent part that has undergone a comparable
degree of aging.
    (5) We may direct you to preferentially select certain types of
vehicles, vehicles from certain model years. or vehicles within some
range of service accumulation. We will not direct you to select
vehicles that are 10 or more years old, or vehicles with an odometer
reading exceeding 85 percent of the engine's useful life. We will
specify a time frame for completing required testing.
    (b) Perform verification testing with one of the following
procedures, or with an alternative procedure that you demonstrate to be
equally effective:
    (1) Engine dynamometer testing. Measure emissions from engines
equipped with in-use aftertreatment systems on an engine dynamometer as
follows:
    (i) Test the aftertreatment system from at least two engines using
the procedures specified in subpart F of this part and 40 CFR part
1065. Install the aftertreatment system from the selected in-use
vehicle, including all associated wiring, sensors, and related hardware
and software, on one of the following partially complete engines:
    (A) The in-use engine from the same vehicle.
    (B) The emission-data engine used to determine the deterioration
factors.
    (C) A different emission-data engine from the same engine family
that has been stablized as described in 40 CFR 1065.405(c).
    (ii) Perform testing on all certification duty cycles with brake-
specific emission standards (g/hp[middot]hr) to determine whether the
engine meets all the duty-cycle emission standards, including any
compliance allowance, for criteria pollutants. Apply infrequent
regeneration adjustment factors as included in your application for
certification or develop new factors if we request it.
    (iii) Evaluate verification testing for each pollutant
independently. You pass the verification test if at least 70 percent of
tested engines meet standards for each pollutant over all duty cycles.
You fail the verification test if fewer than 70 percent of engines meet
standards for a given pollutant over all duty cycles.
    (2) PEMS testing. Measure emissions using PEMS with in-use engines
that remain installed in selected vehicles as follows:
    (i) Test at least five engines using the procedures specified in
Sec.  1036.555 and 40 CFR part 1065, subpart J.
    (ii) Measure emissions of NOX, HC, and CO as the test
vehicle's normal operator drives over a regular shift-day to determine
whether the engine meets all the off-cycle emission standards that
applied for the engine's original certification. Apply infrequent
regeneration adjustment factors as included in your application for
certification. For Spark-ignition HDE, calculate off-cycle emission
standards for purposes of this subpart by multiplying the FTP duty-
cycle standards in Sec.  1036.104(a) by 1.5 and

rounding to the same number of decimal places.
    (iii) Evaluate verification testing for each pollutant
independently. You pass the verification test if at least 70 percent of
tested engines meet the off-cycle standards including any compliance
allowance and accuracy margin, for each pollutant. You fail the
verification test if fewer than 70 percent of tested engines do not
meet standards for a given pollutant.
    (iv) You may reverse a fail determination under paragraph
(b)(2)(iii) of this section by restarting and successfully completing
the verification test for that year using the procedures specified in
paragraph (b)(1) of this section. If you do this, you must use the
verification testing procedures specified in paragraph (b)(1) of this
section for all remaining verification testing for the engine family.
    (c) You may stop testing under the verification test program and
concede a fail result before you meet all the testing requirements of
this section.
    (d) Prepare a report to describe your verification testing each
year. Include at least the following information:
    (1) Identify whether you tested using the procedures specified in
paragraph (b)(1) or (2) of this section.
    (2) Describe how the test results support a pass or fail decision
for the verification test. For in-field measurements, include
continuous 1 Hz data collected over the shift-day and binned emission
values determined under Sec.  1036.530.
    (3) If your testing included invalid test results, describe the
reasons for invalidating the data. Give us the invalid test results if
we ask for them.
    (4) Describe the types of vehicles selected for testing. If you
determined that any selected vehicles with enough mileage accumulation
were not suitable for testing, describe why you chose not to test them.
    (5) For each tested engine, identify the vehicle's VIN, the
engine's serial number, the engine's power rating, and the odometer
reading and the engine's lifetime operating hours at the start of
testing (or engine removal).
    (6) State that the tested engines have been properly maintained and
used and describe any noteworthy aspects of each vehicle's maintenance
history. Describe the steps you took to prepare the engines for
testing.
    (7) For testing with engines that remain installed in vehicles,
identify the date and location of testing. Also describe the ambient
conditions and the driving route over the course of the shift-day.
    (e) Send electronic reports to the Designated Compliance Officer
using an approved information format. If you want to use a different
format, send us a written request with justification.
    (1) You may send us reports as you complete testing for an engine
instead of waiting until you complete testing for all engines.
    (2) We may ask you to send us less information in your reports than
we specify in this section.
    (3) We may require you to send us more information to evaluate
whether your engine family meets the requirements of this part.
    (4) Once you send us information under this section, you need not
send that information again in later reports.
    (5) We will review your test report to evaluate the results of the
verification testing at each stage. We will notify you if we disagree
with your conclusions, if we need additional information, or if you
need to revise your testing plan for future testing.

Sec.  1036.250  Reporting and recordkeeping for certification.

    (a) By September 30 following the end of the model year, send the
Designated Compliance Officer a report including the total nationwide
production volume of engines you produced in each engine family during
the model year (based on information available at the time of the
report). Report the production by serial number and engine
configuration. You may combine this report with reports required under
subpart H of this part. We may waive the reporting requirements of this
paragraph (a) for small manufacturers.
    (b) Organize and maintain the following records:
    (1) A copy of all applications and any summary information you send
us.
    (2) Any of the information we specify in Sec.  1036.205 that you
were not required to include in your application.
    (3) A detailed history of each emission-data engine. For each
engine, describe all of the following:
    (i) The emission-data engine's construction, including its origin
and buildup, steps you took to ensure that it represents production
engines, any components you built specially for it, and all the
components you include in your application for certification.
    (ii) How you accumulated engine operating hours (service
accumulation), including the dates and the number of hours accumulated.
    (iii) All maintenance, including modifications, parts changes, and
other service, and the dates and reasons for the maintenance.
    (iv) All your emission tests, including documentation on routine
and standard tests, as specified in part 40 CFR part 1065, and the date
and purpose of each test.
    (v) All tests to diagnose engine or emission control performance,
giving the date and time of each and the reasons for the test.
    (vi) Any other significant events.
    (4) Production figures for each engine family divided by assembly
plant.
    (5) Engine identification numbers for all the engines you produce
under each certificate of conformity.
    (c) Keep routine data from emission tests required by this part
(such as test cell temperatures and relative humidity readings) for one
year after we issue the associated certificate of conformity. Keep all
other information specified in this section for eight years after we
issue your certificate.
    (d) Store these records in any format and on any media, as long as
you can promptly send us organized, written records in English if we
ask for them. You must keep these records readily available. We may
review them at any time.

Sec.  1036.255  EPA oversight on certificates of conformity.

    (a) If we determine an application is complete and shows that the
engine family meets all the requirements of this part and the Act, we
will issue a certificate of conformity for the engine family for that
model year. We may make the approval subject to additional conditions.
    (b) We may deny an application for certification if we determine
that an engine family fails to comply with emission standards or other
requirements of this part or the Clean Air Act. We will base our
decision on all available information. If we deny an application, we
will explain why in writing.
    (c) In addition, we may deny your application or suspend or revoke