failure by a mechanism that does not represent normal aging. An example
of temperatures to run the degradation experiment at for a small-pore
copper zeolite SCR catalyst is 600 [deg]C, 650 [deg]C, and 725 [deg]C.
    (2) For each temperature selected, perform testing to assess the
aging metric at different times. These time intervals do not need to be
evenly spaced and it is typical to run these experiments using
increasing time intervals (e.g., after 2, 4, 8, 16, and 32 hours). Use
good engineering judgment to stop each temperature experiment after
sufficient data has been generated to characterize the shape of the
deactivation behavior at a given temperature.
    (d) Generate a fit of the deactivation data generated in paragraph
(b) of this section at each temperature using the generalized
deactivation equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.147

Where:

[Omega] = aging metric.
k = thermal aging rate constant for a given temperature.
[Omega]EQ = aging metric at equilibrium (set to 0 unless
there is a known activity minimum).
m = model order (the model order should be set at the lowest value
that best fits the data at all temperatures, minimum = 1).

    (e) Using the data pairs of temperature and thermal aging rate
constant, k, from paragraph (c)(2) of this section, determine the
thermal reactivity coefficient, Ea, by performing a
regression analysis of the natural log of k versus the inverse of
temperature, T, in Kelvin. Determine Ea from the slope of
the resulting line using the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.148

Where:

m = the slope of the regression line of ln(k) versus 1/T.
R = molar gas constant.

Sec.  1065.1139  Aging cycle generation.

    Generation of the accelerated aging cycle for a given application
involves analysis of the field data to determine a set of aging modes
that will represent that field operation. There are two methods of
cycle generation, each of which is described separately below. Method 1
involves the direct application of field data and is used when the
recorded data includes sufficient exhaust flow and temperature data to
allow for determination of aging conditions directly from the field
data set and must be available for all of the key components. Method 2
is meant to be used when insufficient flow and temperature data is
available from the field data. In Method 2, the field data is used to
weight a set of modes derived from the laboratory certification cycles
for a given application. These weighted modes are then combined with
laboratory recorded flow and temperatures on the certification cycles
to derive aging modes. There are two different cases to consider for
aging cycle generation, depending on whether or not a given
aftertreatment system incorporates the use of a periodic regeneration
event. For the purposes of this section, a ``regeneration'' is any
event where the operating temperature of some part of the
aftertreatment system is raised beyond levels that are observed during
normal (non-regeneration) operation. The analysis of regeneration data
is considered separately from normal operating data.
    (a) Cycle generation process overview. The process of cycle
generation begins with the determination of the number of bench aging
hours. The input into this calculation is the number of real or field
hours that represent the useful life for the target application. This
could be given as a number of hours or miles, and for miles, the
manufacturer must use field data and good engineering judgment to
translate this to an equivalent number of operating hours for the
target application. The target for the accelerated aging protocol is a
10-time acceleration of the aging process, therefore the total number
of aging hours is always set at useful life hours divided by 10. For
example, if an on-highway heavy duty engine has a full useful life of
750,000 miles and this is determined to be represented by 24,150 field
hours, the target duration for the DAAAC protocol for this application
would be 2,415 bench-aging hours. The 2,415 hours will then be divided
among different operating modes that will be arranged to result in
repetitive temperature cycling over that period. For systems that
incorporate periodic regeneration, the total duration will be split
between regeneration and normal (non-regeneration) operation. The
analysis of normal operation data is given in paragraph (b) of this
section. The analysis of regeneration data is given in paragraph (c) of
this section.
    (b) Analysis of normal (non-regeneration) operating data. This
analysis develops a reduced set of aging modes that represent normal
operation. As noted earlier, there are two methods for conducting this
analysis, based on the data available.
    (1) Method 1--Direct clustering. Use Method 1 when sufficient
exhaust flow and temperature data are available directly from the field
data. The data requirements for Method 1 are described in Sec.
1065.1133(b)(1). The method involves three steps: clustering analysis,
mode consolidation, and cycle building.
    (i) The primary method for determining modes from a field data set
involves the use of k-means clustering. K-means clustering is a method
where a series of observations is partitioned into set of clusters of
``similar'' data points, where every observation is a member of a
cluster with the nearest mean, which is referred to as the centroid of
that cluster. The number of clusters is a parameter of the analysis,
and the k-means algorithm generally seeks an optimal number of clusters
to minimize the least-squares distance of all points to their
respective centroids. There are a number of different commercially
available software programs to perform k-means clustering, as well as
freely available algorithm codes. K-means clustering can arrive at many
different solutions, and we are providing the following guidance to
help select the optimal solution for use in accelerated aging cycle
generation. The process involves analyzing the data multiple time using
an increasing number of clusters for each analysis. Use at least 5
clusters, and we recommend developing solutions for the range between 5
and 8 clusters, although you may use more if desired. Each cluster is a
potential aging mode with a temperature and flow rate defined by the
centroid. More clusters result in more aging modes, although this
number may be reduced later via model consolidation.
    (ii) The cubic clustering criteria (CCC) is a metric calculated for
each solution having a different number of clusters.

The computation of CCC is complex and described in more detail in the
following reference. The CCC computation is normally available as one
of the metrics in commercially available software packages that can be
used for k-means clustering. The optimal solution is typically the one
with the number of clusters corresponding to the highest CCC.
    (iii) Check each solution, starting with the one with the highest
CCC to determine if it satisfies the following requirements:
    (A) No more than one cluster contains fewer than 3% of the data
points.
    (B) The temperature ratio between the centroid with the maximum
temperature and the centroid with the minimum temperature is at least
1.6 for clusters containing more than 3% of the data points.
    (C) If that solution does not satisfy these requirements move to
the solution with the next highest CCC.
    (iv) The process described in paragraph (c)(1)(iii) of this section
generally works well for most data sets, but if you have difficulty
with the CCC metric in a particular data set, use good engineering
judgment to leverage additional criteria to help the down-selection
process. Examples of alternate clustering metrics include a Davies-
Bouldin Index (optimizing on the minimum value) or a Calinski-Harabasz
Index (optimize on the maximum value).
    (v) The initial candidate mode conditions are temperature and flow
rate combinations that are the centroids for each cluster from the
analysis in paragraph (c)(1)(iii) of this section. As part of the
analysis, you must also determine the 10th percentile and 90th
percentile temperatures for each cluster. These additional values may
be needed later for the cycle heat load tuning process described in
Sec.  1065.1143.
    (vi) The mode weight factor for a given cluster is the fraction
data points contained within that cluster.
    (2) Method 2--Cluster-based weighting of certification cycle modes.
Use Method 2 if there is insufficient exhaust flow and temperature data
from the field at the time the cycle is being developed. The data
requirements for Method 2 are described in Sec.  1065.1133(b)(2). You
also need laboratory data recorded in the form of 1 Hz data sets for
the regulatory duty cycles you are certifying to for your application
as described in the standard setting part. Include exhaust flow rate
and the inlet temperature for each key catalyst component in the
laboratory data sets, as described in paragraph (e) of this section.
The laboratory data sets must also include parameters that match the
field data as described in Sec.  1065.1133(b)(2), which will be used to
facilitate the clustering analysis.
    (i) Perform k-means clustering is described in Sec.
1065.1133(b)(1) but using data sets containing the two parameters
recorded in the field data sets. For example, you might use speed and
torque, as recorded both in the field and the laboratory for Method 2
clustering.
    (ii) Determine the fraction of points from each of the regulatory
laboratory duty-cycles that are within each cluster, in addition to the
overall fraction of points from the entire data set.
    (iii) For each cycle, calculate a square sum error, SSE, as
follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.149

Where:

i = an indexing variable that represents one cluster.
N = total number of clusters.
Cycleprob = the fraction of points in a given cluster, i,
for the regulatory duty-cycle of interest.
RefDataprob = the fraction of points in a given cluster,
i, for the full data set.

    (iv) For each cycle, calculate a dissimilarity index as follows:
    [GRAPHIC] [TIFF OMITTED] TR24JA23.150

Where:

SSE = sum square error from Eq. 1065.1139-2.
Ng = total number of clusters.

    (v) If you have more than one regulatory duty cycle, weight the
regulatory cycles.
    (A) Determine the weighting factors for a given regulatory cycle,
wi, by solving a system of equations:
[GRAPHIC] [TIFF OMITTED] TR24JA23.151

Where:

di = dissimilarity for a given regulatory cycle, i.
dj = dissimilarity for a given regulatory cycle, j.

    (B) For example, for three duty cycles, calculate w1 as
follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.152

    (C) Calculate subsequent wi values after calculating
w1 as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.153

    (D) Calculate the sum of the weighting factors to verify that they
are equal to one.
[GRAPHIC] [TIFF OMITTED] TR24JA23.154

Where:

n = number of regulatory cycles for the application.

    (vi) For each regulatory cycle determine the average exhaust flow
and the average inlet temperature for each key catalyst. Determine the
25th and 90th percentile inlet temperatures for the primary catalyst
and the respective associated exhaust flow rate for each data point.
    (vii) Use the cycle weights from paragraph (b)(2)(v) of this
section and the mode conditions from paragraph (b)(2)(vi) of this
section to generate a set of candidate aging modes by multiplying the
cycle weight factor, w[cycle] by 0.25 for the 25th
percentile temperature mode, 0.65 for the 50th percentile temperature
mode, and by 0.10 for the 90th percentile temperature mode. This will
generate a weighted set of mode numbers three times the number of
regulatory cycles for the target application. Each mode will have a
target temperature and exhaust flow rate.

    (viii) If you have only one regulatory cycle for your application,
use the cycle modes and weighting factors as they are given in the
standard setting part.
    (3) Determination of mode total durations. The output for either
method will be a set of mode exhaust conditions, with an associated
weighting factor for each mode. Multiply the mode weight factors by the
total number of normal operating (non-regenerating) hours, to get a
target mode duration for each mode. This will be used in the heat load
calculations.
    (c) Mode consolidation. Sometimes the clustering analysis process
will generate multiple modes that are very similar to each other in
temperature, such that although they are distinct modes they will not
have a significantly different impact on aftertreatment aging. To
reduce the complexity of the aging cycle, you may consolidate modes
that are similar into a single mode as described below.
    (1) Consolidate any two or more modes which have a target
temperature within 10 [deg]C into a single mode. If you choose to do
this, the target temperature of the single consolidated mode is the
temperature associated with the highest weight factor mode before
consolidation. If the modes being consolidated all have weighting
factors within 0.05 of each other, use the highest temperature among
the modes.
    (2) Use the highest exhaust flow target among the modes being
combined as the target exhaust flow for new consolidate mode.
    (3) Use the combined sum of the weighting factors for all modes
being consolidate as the weighting factor for the new consolidated
mode. Similarly, the total duration of the new consolidated mode is the
sum of the durations of the modes being consolidated.
    (d) Analysis of regeneration data. Regeneration data is treated
separately from the normal operating mode data. Generally, the target
for accelerated aging cycle operation is to run all of the
regenerations that would be expected over the course of useful life. If
multiple types of regeneration are conducted on different system
components, each type of regeneration must be analyzed separately using
the steps in this paragraph (d). The data requirements for input into
this process are described in Sec.  1065.1133(b)(3). The process
described below is meant to determine a representative regeneration
profile that will be used during aging. You may also ask us to allow
the use of other engineering data or analysis to determine a
representative regeneration profile.
    (1) The total number of regenerations that will be run during the
accelerated aging process will be the same as the total number of
regenerations over useful life. Calculate this number by dividing the
total number of useful life hours by the interval between regenerations
as determined in Sec.  1065.1133(b)(3).
    (2) Use the 1 Hz regeneration data to determine an appropriate
regeneration profile. The recorded regeneration event begins when the
engine indicates it has started regeneration using the recorded
regeneration indicator and ends when the aftertreatment has returned
back to the normal operating temperature after the flag indicates the
regeneration is complete.
    (3) For each recorded regeneration, calculate the cumulative
deactivation, Dt, using the equations in paragraph (e) of
this section.
    (4) If you have a large number of recorded regenerations in your
data set, select a regeneration event with a cumulative deactivation
representing the 75th percentile of the distribution of heat loads in
your recorded data set. If you have a smaller number of recorded
regenerations, such that you cannot clearly identify the real
distribution, select the recorded regeneration with the highest
recorded cumulative deactivation.
    (5) This regeneration event will be used as the regeneration
profile for that type of event during aging. The profile should include
the entire event, include the temperature ramp and cool-down period.
    (6) The regeneration must be conducted in the same manner as it is
run in the field. For instance, if the regeneration temperature is
generated from an exothermic reaction by injecting fuel in front of a
DOC, this methodology should also be used during bench aging.
    (7) If part of the system is at a lower temperature during
regeneration because it is upstream of the temperature generating
component, the set the target temperature for the aftertreatment system
inlet to be equivalent to the system inlet temperature used during the
highest duration non-regeneration mode, or 350 [deg]C, whichever is
lower.
    (e) Heat load calculation and tuning for systems that have
regeneration events. Perform this procedure after the preliminary
cycles are completed for both normal and regeneration operation. The
target cumulative deactivation is determined from the input field data,
and then a similar calculation is performed for the preliminary aging
cycle. If the cumulative deactivation for the preliminary cycle does
not match cumulative deactivation from the field data, then the cycle
is tuned over a series of steps until the target is matched.
    (1) The deactivation for a given catalyst is calculated for each
time step as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.155

Where:

Di = incremental deactivation for time step i.
Ea = thermal reactivity coefficient for the catalyst as
determined in Sec.  1065.1137.
R = molar gas constant in kJ/mol[middot]K.
Tstd = standard temperature = 293.15 K.
T = catalyst temperature in K.

    (2) Calculate the cumulative deactivation, Dt, for a
given catalyst over a series of time steps, N, using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.156

Where:

i = an indexing variable that represents one time step.
N = total number of cumulative deactivation time steps in the data
set.
Di = incremental deactivation for each time step.

    (3) Calculate the cumulative deactivation, Dt, for the
input field data set. The time step for the calculations should be 1
second for 1-Hz input data.
    (i) First calculate Dt for the non-regeneration portion
of the field data set. For Method 2 use the 1-Hz data from the
regulatory cycles as the field data set.
    (ii) Divide the calculate field Dt by the number of
hours represented in the field data set.
    (iii) Multiply the hourly Dt by the number of hours
required to reach full useful life. This is the target
Dt,field-normi.
    (iv) Multiply the total number of regenerations for full useful
life by the cumulative deactivation Dt for the target
regeneration profile determined in paragraph (d)(4) of this section.
This is the target Dt,field-regen.
    (v) The total target cumulative deactivation for the field data,
Dt,field, is the sum of Dt,field-normi and
Dt,field-regen.
    (4) Calculate the cumulative deactivation for the candidate aging
cycle generated under paragraphs (c) and (d) of this section as
follows:
    (i) Using the modes and mode durations for normal operation
generated in paragraph (c) of this section, calculate the cumulative
deactivation, Dt,cycle-norm, using the

method given in paragraph (e)(2) of this section.
    (ii) The total cumulative deactivation for the candidate aging
cycle, Dt, is the sum of Dt,cycle-norm and
Dt,field-regen.
    (5) If Dt,cycle is within 1% of
Dt,field, the candidate cycle is deemed representative and
may be used for aging.
    (6) If Dt,cycle is not within 1% of
Dt,field, the candidate cycle must be adjusted to meet this
criterion using the following steps. It should be noted that if the
Dt,cycle is outside of the criteria it will usually be lower
than the Dt,field.
    (i) Increase the duration of the stable portion of the regeneration
profile, which is defined as the portion of the regeneration profile
where the temperature has completed ramping and is being controlled to
a stationary target temperature. Note that this will increase the
number of hours of regeneration time. You must compensate for this by
decreasing the total number of normal operation (non-regeneration)
hours in the cycle. Recalculate the duration of all the normal
operation modes. You may not increase the duration of the stable
portion of the regeneration profile by more than a factor of 2. If you
reach this limit and you still do not meet the criteria in paragraph
(e)(5) of this section, proceed to the next step.
    (ii) Increase the target temperature of the stable portion of the
regeneration profile by the amount necessary to reach the target
criteria. You may not increase this temperature higher than the
temperature observed in the regeneration profile with the highest
Dt observed in the field. If you reach this limit and you
still do not meet the criteria in paragraph (e)(5) of this section,
proceed to the next step.
    (iii) Increase the target temperature of the highest temperature
normal operation mode. You may not increase this temperature above the
90th percentile determined in paragraph (b)(1)(v) of this section for
Method 1, or above the maximum temperature for the regulatory cycle
from which the mode was derived for Method 2. If you reach this limit
and you still do not meet the criteria in paragraph (e)(5) of this
section, you may repeat this step using the next highest temperature
mode, until you reach the target, or all modes have been adjusted.
    (iv) If you are unable to reach the target deactivation by
following paragraphs (e)(6)(i) through (iii) of this section, use good
engineering judgment to increase the number of regenerations to meet
the criteria in paragraph (e)(5) of this section. Note that this will
increase the total regeneration hours, therefore you must decrease the
number of normal operation hours and re-calculate mode durations for
the normal operation modes.
    (f) Heat load calculation and tuning for systems that do not have
regeneration events. Follow the steps described for systems with
regeneration events to calculate Dt,field and
Dt,cycle, omitting the steps related to regeneration events.
The Dt,cycle will be well below the Dt,field.
Follow the steps given below to adjust the cycle until you meet the
criteria in paragraph (e)(5) of this section.
    (1) Increase the temperature of the highest temperature mode. Use
good engineering judgment to ensure that this temperature does not
exceed the limits of the catalyst in a way that might cause rapid
deactivation or failure via a mechanism that is not considered normal
degradation.
    (2) Increase the duration of the highest temperature mode and
decrease the duration of the other modes in proportion. You may not
increase the duration highest temperature mode by more than a factor of
2.
    (g) Final aging cycle assembly. The final step of aging cycle
development is the assembly of the actual cycle based on the mode data
from either paragraph (e) of this section for systems with infrequent
regeneration, or paragraph (f) of this section for systems that do not
incorporate infrequent regeneration. This cycle will repeat a number of
times until the total target aging duration has been reached.
    (1) Cycle assembly with infrequent regenerations. For systems that
use infrequent regenerations, the number of cycle repeats is equal to
the number of regeneration events that happen over full useful life.
The infrequent regenerations are placed at the end of the cycle. The
total cycle duration of the aging cycle is calculated as the total
aging duration in hours divided by the number of infrequent
regeneration events. In the case of systems with multiple types of
infrequent regenerations, use the regeneration with the lowest
frequency to calculate the cycle duration.
    (i) If you have multiple types of infrequent regenerations, arrange
the more frequent regenerations such that they are spaced evenly
throughout the cycle.
    (ii) Determine the length of the normal (non-regeneration) part of
the cycle by subtracting the regeneration duration, including any
regeneration extension determined as part of cycle tuning from
paragraph (e) of this section, from the total cycle duration. If you
have multiple types of regeneration, then the combined total duration
of regeneration events performed in the cycle must be subtracted from
the total. For example, if you have one type of regeneration that is
performed for 30 minutes every 30 cycle hours, and a second type that
is performed for 30 minutes every 10 cycle hours (such that 3 of these
secondary events will happen during each cycle), then you would
subtract a total of 2 hours of regeneration time from the total cycle
duration considering all 4 of these events.
    (iii) Divide the duration of the normal part of the cycle into
modes based on the final weighting factors determined in paragraph (c)
of this section following any mode consolidation.
    (iv) Place the mode with the lowest temperature first, then move to
the highest temperature mode, followed by the next lowest temperature
mode, and then the next highest mode, continuing in this alternating
pattern until all modes are included.
    (v) Transition between normal modes within (60 to 300) seconds. The
transition period is considered complete when you are within 5 [deg]C of the target temperature for the primary key component.
Transitions may follow any pattern of flow and temperature to reach
this target within the required 300 seconds.
    (vi) For normal modes longer than 30 minutes, you may count the
transition time as time in mode. Account for the transition time for
modes shorter than 30 minutes by shortening the duration of the longest
mode by an equivalent amount of time.
    (vii) If the shortest normal operating mode is longer than 60
minutes, you must divide the normal cycle into shorter sub-cycles with
the same pattern in paragraph (g)(1)(iii) of this section, but with
shorter durations, so that the pattern repeats two or more times. You
must divide the cycle into sub-cycles until the duration of the
shortest mode in each sub-cycle is no longer than 30 minutes. No mode
may have a duration shorter than 15 minutes, not including transition
time.
    (viii) If a regeneration event is scheduled to occur during a
normal mode, shift the start of regeneration to the end of the nearest
normal mode.
    (2) Cycle assembly without infrequent regenerations. For systems
that do not use infrequent regenerations, the cycle will be arranged to
achieve as much thermal cycling as possible using the following steps.
    (i) Assign a duration of 15 minutes to the mode with the lowest
weight factor. Calculate the duration of the remaining modes in
proportion to the final weight factors after mode durations have been

adjusted during heat load tuning in paragraph (f) of this section.
    (ii) Place the mode with the lowest temperature first, then move to
the highest temperature mode, followed by the next lowest temperature
mode, and then the next highest mode, continuing in this alternating
pattern until all modes are included.
    (iii) Transition between normal modes within (60 to 300) seconds.
The transition period is considered complete when you are within 5 [deg]C of the target temperature for the primary key component.
Transitions may follow any pattern of flow and temperature to reach
this target within the required 300 seconds.
    (iv) For normal modes longer than 30 minutes, you may count the
transition time as time in mode. Account for the transition time for
modes shorter than 30 minutes by shortening the duration of the longest
mode by an equivalent amount of time.
    (v) This cycle will be repeated the number of times necessary to
reach the target aging duration.
    (h) Determination of accelerated oil exposure targets. The target
oil exposure rate during accelerated aging is 10 times the field
average oil consumption rate determined in Sec.  1065.1133(a)(2). You
must achieve this target exposure rate on a cycle average basis during
aging. Use good engineering judgment to determine the oil exposure
rates for individual operating modes that will achieve this cycle
average target. For engine-based aging stands you will likely have
different oil consumption rates for different modes depending on the
speed and load conditions you set. For burner-based aging stands, you
may find that you have to limit oil exposure rates at low exhaust flow
or low temperature modes to ensure good atomization of injected oil. On
a cycle average basis, the portion of oil exposure from the volatile
introduction pathway (i.e., oil doped in the burner or engine fuel)
must be between (10 to 30)% of the total. The remainder of oil exposure
must be introduced through bulk pathway.
    (1) Determination of accelerated fuel sulfur exposure targets. The
target sulfur exposure rate for fuel-related sulfur is determined by
utilizing the field mean fuel rate data for the engine determined in
Sec.  1065.1133(a)(3). Calculate the total sulfur exposure mass using
this mean fuel rate, the total number of non-accelerated hours to reach
full useful life, and a fuel sulfur level of 10 ppmw.
    (i) For an engine-based aging stand, if you perform accelerated
sulfur exposure by additizing engine fuel to a higher sulfur level,
determine the accelerated aging target additized fuel sulfur mass
fraction, wS, as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.157

Where:

mifuel,field = field mean fuel flow rate.
mifuel,cycle = accelerated aging cycle mean fuel flow
rate.
mSfuel,ref = reference mass of sulfur per mass of fuel =
0.00001 kg/kg
Sacc,rate = sulfur acceleration rate = 10

Example:

mifuel,field = 54.3 kg/hr
mifuel,cycle = 34.1 kg/hr
mSfuel,ref = 0.00001 kg/kg.
Sacc,rate = 10.
[GRAPHIC] [TIFF OMITTED] TR24JA23.158

wS,target = 0.000159

    (ii) If you use gaseous SO2 to perform accelerated
sulfur exposure, such as on a burner-based stand, calculate the target
SO2 concentration to be introduced, xSO2,target,
as follows:
[GRAPHIC] [TIFF OMITTED] TR24JA23.159

Where:

mifuel,field = field mean fuel flow rate.
miexhaust,cycle = mean exhaust flow rate during the
burner aging cycle.
xSfuel,ref = reference mol fraction of sulfur in fuel =
10 [micro]mol/mol.
Sacc,rate = sulfur acceleration rate = 10.
Mexh = molar mass of exhaust = molar mass of air.
MS = molar mass of sulfur.

Example:

mifuel,field = 54.3 kg/hr
miexhaust,cycle = 1000.8 kg/hr
xSfuel,ref = 10 [micro]mol/mol
Sacc,rate = 10
Mexh = 28.96559 g/mol
MS = 32.065 g/mol
[GRAPHIC] [TIFF OMITTED] TR24JA23.160

xSO2,target = 4.90 [micro]mol/mol

    (iii) You may choose to turn off gaseous sulfur injection during
infrequent regeneration modes, but if you do you must increase the
target SO2 concentration by the ratio of total aging time to
total normal (non-regeneration) aging time.
    (2) [Reserved]

Sec.  1065.1141  Facility requirements for engine-based aging stands.

    An engine-based accelerated aging platform is built around the use
of a compression-ignition engine for generation of heat and flow. You
are not

required to use the same engine as the target application that is being
aged. You may use any compression-ignition engine as a bench aging
engine, and the engine may be modified as needed to support meeting the
aging procedure requirements. You may use the same bench aging engine
for deterioration factor determination from multiple engine families.
The engine must be capable of reaching the combination of temperature,
flow, NOX, and oil consumption targets required. We
recommend using an engine platform larger than the target application
for a given aftertreatment system to provide more flexibility to
achieve the target conditions and oil consumption rates. You may modify
the bench aging engine controls in any manner necessary to help reach
aging conditions. You may bypass some of the bench aging engine exhaust
around the aftertreatment system being aged to reach targets, but you
must account for this in all calculations and monitoring to ensure that
the correct amount of oil and sulfur are reaching the aftertreatment
system. If you bypass some of the engine exhaust around the
aftertreatment system, you must directly measure exhaust flow rate
through the aftertreatment system. You may dilute bench aging engine
exhaust prior to introduction to the aftertreatment system, but you
must account for this in all calculations and monitoring to ensure that
the correct engine conditions and the correct amount of oil and sulfur
are reaching the aftertreatment system. Your engine-based aging stand
must incorporate the following capabilities:
    (a) Use good engineering judgment to incorporate a means of
controlling temperature independent of the engine. An example of such a
temperature control would be an air-to-air heat exchanger. The
temperature control system must be designed to prevent condensation in
the exhaust upstream of the aftertreatment system. This independent
temperature control is necessary to provide the flexibility required to
reach temperature, flow, oil consumption targets, and NOX
targets.
    (b) Use good engineering judgment to modify the engine to increase
oil consumption rates to levels required for accelerated aging. These
increased oil consumption levels must be sufficient to reach the bulk
pathway exposure targets determined in Sec.  1065.1139(h). A
combination of engine modifications and careful operating mode
selection will be used to reach the final bulk pathway oil exposure
target on a cycle average. You must modify the engine in a fashion that
will increase oil consumption in a manner such that the oil consumption
is still generally representative of oil passing the piston rings into
the cylinder. Use good engineering judgment to break in the modified
engine to stabilize oil consumption rates. We recommend the following
methods of modification (in order of preference):
    (1) Install the top compression rings inverted (upside down) on all
the cylinders of the bench aging engine.
    (2) If the approach in paragraph (b)(1) of the section is
insufficient to reach the targets, modify the oil control rings in one
or more cylinders to create small notches or gaps (usually no more than
2 per cylinder) in the top portion of the oil control rings that
contact the cylinder liner (care must be taken to avoid compromising
the structural integrity of the ring itself).
    (c) We recommend that the engine-aging stand include a constant
volume oil system with a sufficiently large oil reservoir to avoid oil
``top-offs'' between oil change intervals.
    (d) If the engine-aging stand will be used for aging of systems
that perform infrequent regenerations, the aging stand must incorporate
a means of increasing temperature representative of the target
application. For example, if the target application increases
temperature for regeneration by introducing fuel into the exhaust
upstream of an oxidation catalyst, the aging stand must incorporate a
similar method of introducing fuel into the exhaust.
    (e) If the engine-aging stand will be used for aging systems that
incorporate SCR-based NOX reduction, the aging stand must
incorporate a representative means of introducing DEF at the
appropriate location(s).
    (f) Use good engineering judgment to incorporate a means of
monitoring oil consumption on at least a periodic basis. You may use a
periodic drain and weigh approach to quantify oil consumption. You must
validate that the aging stand reaches oil consumption targets prior to
the start of aging. You must verify oil consumption during aging prior
to each emission testing point, and at each oil change interval.
Validate or verify oil consumption over a running period of at least 72
hours to obtain a valid measurement. If you do not include the constant
volume oil system recommended in paragraph (c) of this section, you
must account for all oil additions.
    (g) Use good engineering judgment to establish an oil change
interval that allows you to maintain relatively stable oil consumption
rates over the aging process. Note that this interval may be shorter
than the normal recommended interval for the engine due to the
modifications that have been made.
    (h) If the engine-aging stand will be used for aging of systems
that incorporate a diesel particulate filter (DPF), we recommend you
perform secondary tracking of oil exposure by using clean (soot free)
DPF weights to track ash loading and compare this mass of ash to the
amount predicted using the measured oil consumption mass and the oil
ash concentration. The mass of ash found by DPF weight should fall
within (55 to 70)% of the of mass predicted from oil consumption
measurements.
    (i) Incorporate a means of introducing lubricating oil into the
engine fuel to enable the volatile pathway of oil exposure. You must
introduce sufficient oil to reach the volatile pathway oil exposure
targets determined in paragraph (h) of this section. You must measure
the rate of volatile pathway oil introduction on a continuous basis.
    (j) If you perform sulfur acceleration by increasing the sulfur
level of the engine fuel, you must meet the target sulfur level within
5 ppmw. Verify the sulfur level of the fuel prior to
starting aging, or whenever a new batch of aging fuel is acquired.
    (k) If you use gaseous SO2 for sulfur acceleration, you
must incorporate a means to introduce the gaseous SO2
upstream of the aftertreatment system. Use good engineering judgment to
ensure that gaseous SO2 is well mixed prior to entering the
aftertreatment system. You must monitor the rate of gaseous
SO2 introduction on a continuous basis.

Sec.  1065.1143  Requirements for burner-based aging stands.

    A burner-based aging platform is built using a fuel-fired burner as
the primary heat generation mechanism. The burner must utilize diesel
fuel and it must produce a lean exhaust gas mixture. You must configure
the burner system to be capable of controlling temperature, exhaust
flow rate, NOX, oxygen, and water to produce a
representative exhaust mixture that meets the accelerated aging cycle
targets for the aftertreatment system to be aged. You may bypass some
of the bench aging exhaust around the aftertreatment system being aged
to reach targets, but you must account for this in all calculations and
monitoring to ensure that the correct amount of oil and sulfur are
reaching the aftertreatment system. The burner system must incorporate
the following capabilities:
    (a) Directly measure the exhaust flow through the aftertreatment
system being aged.

    (b) Ensure transient response of the system is sufficient to meet
the cycle transition time targets for all parameters.
    (c) Incorporate a means of oxygen and water control such that the
burner system is able to generate oxygen and water levels
representative of compression-ignition engine exhaust.
    (d) Incorporate a means of oil introduction for the bulk pathway.
You must implement a method that introduces lubricating oil in a region
of the burner that does not result in complete combustion of the oil,
but at the same time is hot enough to oxidize oil and oil additives in
a manner similar to what occurs when oil enters the cylinder of an
engine past the piston rings. Care must be taken to ensure the oil is
properly atomized and mixed into the post-combustion burner gases
before they have cooled to normal exhaust temperatures, to insure
proper digestion and oxidation of the oil constituents. You must
measure the bulk pathway oil injection rate on a continuous basis. You
must validate that this method produces representative oil products
using the secondary method in Sec.  1065.1141(h) regardless of whether
you will use the burner-based aging stand to age systems which include
a DPF. Use good engineering judgment to select a DPF for the initial
validation of the system. Perform this validation when the burner-based
aging stand is first commissioned or if any system modifications are
made that affect the oil consumption introduction method. We also
recommend that you examine ash distribution on the validation DPF in
comparison to a representative engine aged DPF.
    (e) Incorporate a means of introducing lubricating oil into the
burner fuel to enable the volatile pathway of oil exposure. You must
introduce sufficient oil to reach the volatile pathway oil exposure
targets determined in Sec.  1065.1139(h). You must measure the rate of
volatile pathway oil introduction on a continuous basis.
    (f) If the burner-based aging stand will be used for aging of
systems that perform infrequent regenerations, the aging stand must
incorporate a means of increasing temperature representative of the
target application. For example, if the target application increases
temperature for regeneration by introducing fuel into the exhaust
upstream of an oxidation catalyst, the aging stand must incorporate a
similar method of introducing fuel into the exhaust.
    (g) If the burner-based aging stand will be used for aging of
systems that incorporate SCR-based NOX reduction, the aging
stand must incorporate a representative means of introducing DEF at the
appropriate location(s).
    (h) If the burner-based aging stand will be used for aging of
systems that incorporate a diesel particulate filter (DPF), we
recommend you perform secondary tracking of oil exposure by using clean
(soot free) DPF weights to track ash loading and compare this mass of
ash to the amount predicted using the measured oil consumption mass and
the oil ash concentration. The mass of ash found by DPF weight should
fall within (55 to 70)% of the of mass predicted from oil consumption
measurements.
    (i) You must incorporate a means to introduce the gaseous
SO2 upstream of the aftertreatment system. Use good
engineering judgment to ensure that gaseous SO2 is well
mixed prior to entering the aftertreatment system. You must monitor the
rate of gaseous SO2 introduction on a continuous basis.

Sec.  1065.1145  Execution of accelerated aging, cycle tracking, and
cycle validation criteria.

    The aging cycle generally consists first of practice runs to
validate and tune the final cycle, followed by the actual running of
the repeat cycles needed to accumulate field equivalent hours to reach
full useful life. During the course of the aging run, various aging
parameters are tracked to allow verification of proper cycle execution,
as well as to allow for correction of the aging parameters to stay
within the target limits.
    (a) Preliminary cycle validation runs. Prior to the start of aging,
conduct a number of practice runs to tune the cycle parameters. It is
recommended that initial practice runs be conducted without the
aftertreatment installed, but with the backpressure of the
aftertreatment simulated to help ensure that the tuned cycle is
representative. For final cycle tuning, including regenerations, it is
recommended to use a duplicate or spare aftertreatment system of
similar design to the target system, to avoid damage or excessive
initial aging during the tuning. However, it is permissible to conduct
final tuning using the target system being aged, but you must limit the
total duration to no more than 100 field equivalent hours (10 hours of
accelerated aging), including both thermal and chemical components. The
process followed for these initial runs will vary depending on whether
you are using an engine-based platform or a burner-based platform.
    (1) Engine-based platform. (i) Initial cycle development. It will
be necessary to determine a set of engine modes that will generate the
required combinations of temperature, exhaust flow, oil consumption,
and NOX to meet the target aging requirements. The
development of these modes will be an iterative process using the
engine and independent temperature control features of the aging stand.
This process assumes that you have already implemented the oil
consumption increase modifications, and that these have already been
stabilized and validated to reach the necessary levels of bulk oil
exposure. In general, we recommend the use of higher engine speeds and
loads to generate the desired oil consumption, leveraging the
temperature controls as needed to lower temperature to the targets.
Several iterations will likely be needed to reach all targets. Note
that during transitions you may utilize any combination of conditions
necessary to help primary component catalysts reach the target
temperature and flow conditions within no more than 5 minutes. For
example, you may use a higher exhaust flow rate and lower temperature
to rapidly cool the aftertreatment system to the next temperature.
NOX targets do not need to be met during transitions. It is
permissible to deviate from engine-out NOX emission targets
if needed to reach the temperature, exhaust flow, and oil consumption
targets. We recommend that you maintain a NOX level that is
at the target level or higher, but you may lower NOX by up
to 25%, if necessary, on some modes. Note that validation of oil
consumption requires at least 72 hours of operation. Tune the
parameters for infrequent regeneration towards then end of this initial
development process (such as hydrocarbon injection schedules and
temperature ramp rates).
    (ii) Final cycle validation. Once the cycle is tuned, conduct a
final run using the target aftertreatment system to verify conditions
and log temperatures for heat load calculation. Using the recorded
cycle data, calculate Dt for all primary component catalysts
to ensure that you are matching the desired Dt,cycle
targets. If you are not within 3% of the target
Dt,cycle, adjust the cycle accordingly. Calculate
Dt for any secondary catalyst components to verify that they
are within 3% of either the target Dt or the
target aging metric. Note that the accelerated aging methodology
assumes that the relationship between the temperature of the primary
and secondary catalyst components will the be same as the field
observations. If this relationship deviates in the lab by having more
or less heat transfer through the system, it may be necessary to modify
that relationship on the aging stand. You may need to take measures

such as adding or removing insulation or utilize external cooling fans
to help these parameters match more closely.
    (2) Burner-based platform. (i) Cycle development. The burner-based
platform will be able to meet the exhaust flow, temperature,
NOX, and oil consumption targets directly without the need
for additional cycle development. This process assumes that you have
already implemented and validated your oil consumption exposure methods
to reach the necessary levels of bulk oil exposure. In addition, you
must meet the oxygen and water targets during aging modes within 2% for oxygen and 2% for water. Note that during
transitions you may utilize any combination of conditions necessary to
help primary component catalysts reach the target temperature and flow
conditions within no more than 5 minutes. For example, you may use a
higher exhaust flow rate and lower temperature to rapidly cool the
aftertreatment system to the next temperature. NOX, oxygen,
and water targets do not need to be met during transitions.
    (ii) Final cycle validation. Once the cycle is tuned, conduct a
final run using the target aftertreatment system to verify conditions
and log temperatures for heat load calculation. Using the recorded
cycle data, calculate Dt for all primary components
catalysts to ensure that you are matching the desired
Dt,cycle targets. If you are not within 3% of
the target Dt,cycle, adjust the cycle accordingly. Calculate
Dt for any secondary catalyst components to check that they
are within 3% of either the target Dt or the
target aging metric. Note that the accelerated aging methodology
assumes that the relationship between the temperature of the primary
and secondary catalyst components will the be same as that observed in
the field. If this relationship deviates in the lab by having more or
less heat transfer through the system, it may be necessary to modify
that relationship on the aging stand. You may need to take measures
such as adding or removing insulation or utilize external cooling fans
to help these parameters match more closely.
    (b) Aftertreatment break in. Break in the emission-data engine and
aftertreatment prior to the initial zero-hour test by running both on
an engine dynamometer as described in subpart E of this part. Use good
engineering judgment to develop a representative cycle that represents
the field data. You may use the same data used for accelerated aging
cycle development or other data. If your system utilizes infrequent
regeneration, include at least one complete regeneration event, but we
recommend that you include at least two such events to stabilize
emissions performance. Your break in process must include at least 125
hours of engine operation with the aftertreatment system. You may ask
to use a longer break in duration based on good engineering judgment,
to ensure that emission performance is stabilized prior to the zero-
hour testing.
    (c) Initial emission testing. Prior to the start of accelerated
aging conduct the initial zero-hour emission test and any required
engine dynamometer aging following the requirements of the standard
setting part for your engine. Dynaometer aging hours count toward the
total aging hours.
    (d) Accelerated aging. Following zero-hour emission testing and any
engine dynamometer aging, perform accelerated aging using the cycle
validated in either paragraph (a)(1) or (2) of this section. Repeat the
cycle the number of times required to reach full useful life equivalent
aging. Interrupt the aging cycle as needed to conduct any scheduled
intermediate emission tests, clean the DPF of accumulated ash, and for
any facility releated reasons. We recommended you interrupt aging at
the end of a given aging cycle, following the completion of any
scheduled infrequent regeneration event.
    (e) QA tracking and validation. During aging, track a number of
aging parameters to ensure that fall within the required limits.
Correct aging parameters as need to remain within the required control
limits.
    (1) Thermal load tracking. For each primary catalyst component,
generate a target line which describes the relationship between aging
hours on the cycle and cumulative deactivation, Dt. Generate
control limit lines that are 3% of the target line. You
must remain within these control limits over the course of aging.
Adjust aging parameters as needed to remain within these limits for the
primary catalyst components. For each secondary catalyst component,
generate both a target Dt line and a line describing the
target behavior of the aging metric directly. You must remain within
either 10% of either the Dt line or 3% of the aging metric target line for any secondary catalyst
component. Adjust aging parameters as needed to remain within these
limits noting that you must remain within limits for the primary
components. Adjusting the secondary catalyst aging may require altering
heat transfer through the system to make it more representative of the
field aging.
    (2) Oil consumption tracking. Generate a target oil consumption
line for both the bulk and volatile pathway which describes the
relationship between oil exposure and aging hours on the cycle. For the
engine-based stand the control limits are 10% for total oil
consumption, noting that the volatile pathway must not exceed 30% of
the total. For the burner-based stand, the controls limits are 5% for both pathways, which are tracked separately.
    (i) Changing engine oil. For an engine-based platform, periodically
change engine oil to maintain stable oil consumption rates and maintain
the health of the aging engine. Interrupt aging as needed to perform
oil changes. Perform a drain-and-weigh measurement. Following an oil
change you must run at least 4 hours with the exhaust bypassing the
aftertreatment system to stabilize the new oil. If you see a sudden
change in oil consumption it may be necessary to stop aging and either
change oil or correct an issue with the accelerated oil consumption. If
the aging engine requires repairs to correct an oil consumption issue
in the middle of aging, you must re-validate the oil consumption rate
for 72 hours before you continue aging. The engine exhaust should be
left bypassing the aftertreatment system until the repaired engine has
been validated.
    (ii) Secondary oil consumption validation. If your aftertreatment
includes a diesel particulate filter, we recommend that you perform
secondary validation of oil consumption by using clean (soot free) DPF
weights to track ash loading and compare this mass of ash to the amount
predicted using the measured oil consumption mass and the oil ash
concentration. The mass of ash found by DPF weight should fall within a
range of (55 to 70)% of the of mass predicted from oil consumption
measurements. Perform this validation at the end of aging, at any
intermediate emission test points, and at any point where you need to
clean the DPF of accumulated ash in according with recommended
maintenance.
    (iii) Sulfur tracking. Generate a fuel sulfur exposure line
describing the relationship between aging hours and cumulative target
sulfur exposure mass. The control limits for sulfur exposure are 3%. Log actual fuel consumption and the measured fuel sulfur
level of the current batch of fuel (if you are doping fuel to
accelerate sulfur exposure) for engine stand aging. Use these
measurements to ensure that sulfur exposure remains within the control
limits. Adjust sulfur doping levels in the fuel from batch to batch as
needed to stay within limits. If you use gaseous SO2 for
sulfur acceleration, monitor the mass flow rate of the gaseous sulfur.
Use these measurements to calculate total

sulfur mass exposure, and correct SO2 gas flow rates as
needed to stay within the control limits.
    (f) Emission testing at intermediate and final test points. Conduct
emission testing at the end of aging and at any intermediate emission
test points as described in the standard setting part. Following
installation of the aged aftertreatment system on the emission-data
engine at intermediate or final test points, prior to the start of
emission testing, use good engineering judgment to operate the engine
and aftertreatment system for a number of hours to stabilize emission
controls and to allow any adaptive controls to update. Declare the
number of stabilization hours prior to the start of the accelerated
aging program.

PART 1066--VEHICLE-TESTING PROCEDURES

0
269. The authority citation for part 1066 continues to read as follows:

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

0
270. Amend Sec.  1066.110 by revising paragraphs (b)(1)(vi), (b)(2)(i)
and (b)(2)(v) introductory text to read as follows:

Sec.  1066.110  Equipment specifications for emission sampling systems.

* * * * *
    (b) * * *
    (1) * * *
    (vi) You must seal your system to the extent necessary to ensure
that any remaining leaks do not affect your ability to demonstrate
compliance with the applicable standards in this chapter. We recommend
that you seal all known leaks.
* * * * *
    (2) * * *
    (i) For PM background measurement, the following provisions apply
in addition to the provisions in 40 CFR 1065.140(b):
* * * * *
    (v) If you choose to dilute the exhaust by using a remote mix tee,
which dilutes the exhaust at the tailpipe, you may use the following
provisions consistent with good engineering judgment, as long as they
do not affect your ability to demonstrate compliance with the
applicable standards in this chapter:
* * * * *

0
271. Amend Sec.  1066.220 by revising paragraph (b) to read as follows:

Sec.  1066.220  Linearity verification for chassis dynamometer systems.

* * * * *
    (b) Performance requirements. If a measurement system does not meet
the applicable linearity criteria in Table 1 of this section, correct
the deficiency by re-calibrating, servicing, or replacing components as
needed. Repeat the linearity verification after correcting the
deficiency to ensure that the measurement system meets the linearity
criteria. Before you may use a measurement system that does not meet
linearity criteria, you must demonstrate to us that the deficiency does
not adversely affect your ability to demonstrate compliance with the
applicable standards in this chapter.
* * * * *

0
272. Amend Sec.  1066.301 by revising paragraph (b) to read as follows:

Sec.  1066.301  Overview of road-load determination procedures.

* * * * *
    (b) The general procedure for determining road-load force is
performing coastdown tests and calculating road-load coefficients. This
procedure is described in SAE J1263 and SAE J2263 (incorporated by
reference in Sec.  1066.1010). Continued testing based on the 2008
version of SAE J2263 is optional, except that it is no longer available
for testing starting with model year 2026. This subpart specifies
certain deviations from those procedures for certain applications.
* * * * *

0
273. Amend Sec.  1066.415 by revising paragraph (e)(2) to read as
follows:

Sec.  1066.415  Vehicle operation.

* * * * *
    (e) * * *
    (2) If vehicles have features that preclude dynamometer testing,
you may modify these features as necessary to allow testing, consistent
with good engineering judgment, as long as it does not affect your
ability to demonstrate that your vehicles comply with the applicable
standards in this chapter. Send us written notification describing
these changes along with supporting rationale.
* * * * *

0
274. Amend Sec.  1066.420 by revising paragraph (b) to read as follows:

Sec.  1066.420  Test preparation.

* * * * *
    (b) Minimize the effect of nonmethane hydrocarbon contamination in
the hydrocarbon sampling system for vehicles with compression-ignition
engines as follows:
    (1) For vehicles at or below 14,000 pounds GVWR, account for
contamination using one of the following methods:
    (i) Introduce zero and span gas during analyzer calibration using
one of the following methods, noting that the hydrocarbon analyzer flow
rate and pressure during zero and span calibration (and background bag
reading) must be exactly the same as that used during testing to
minimize measurement errors:
    (A) Close off the hydrocarbon sampling system sample probe and
introduce gases downstream of the probe making sure that you do not
pressurize the system.
    (B) Introduce zero and span gas directly at the hydrocarbon
sampling system probe at a flow rate greater than 125% of the
hydrocarbon analyzer flow rate allowing some gas to exit probe inlet.
    (ii) Perform the contamination verification in paragraph (b)(2) of
this section, except use 0.5 [mu]mol/mol in 40 CFR 1065.520(f)(8)(iii).
    (2) For vehicles above 14,000 pounds GVWR, verify the amount of
nonmethane hydrocarbon contamination as described in 40 CFR
1065.520(f).
* * * * *

0
275. Amend Sec.  1066.710 by revising the introductory text and
paragraph (b)(1), removing Figure 1 of Sec.  1066.710, and adding
paragraph (f) to read as follows:

Sec.  1066.710  Cold temperature testing procedures for measuring CO
and NMHC emissions and determining fuel economy.

    This section describes procedures for measuring carbon monoxide
(CO) and nonmethane hydrocarbon (NMHC) emissions and determining fuel
economy on a cold day using the FTP test cycle (see Sec.  1066.801).
* * * * *
    (b) * * *
    (1) Ambient temperature for emission tests. Measure and record
ambient temperature in the test cell at least once every 60 seconds
during the sampling period. The temperature must be (-7.0 1.7)[deg]C at the start of the test and average temperature must
be (-7.0 2.8)[deg]C during the test. Instantaneous
temperature values may be above -4.0[deg]C or below -9.0[deg]C, but not
for more than 3 minutes at a time during the test. At no time may the
ambient temperatures be below -12.0[deg]C or above -1.0[deg]C.
* * * * *
    (f) The following figure illustrates the cold temperature testing
sequence for measuring CO and NMHC emissions and determining fuel
economy:

Figure 1 to paragraph (f) Sec.  1066.710--Cold Temperature Testing
Sequence for Measuring CO and NMHC Emissions and Determining Fuel
Economy

[GRAPHIC] [TIFF OMITTED] TR24JA23.161

0
276. Amend Sec.  1066.815 by revising paragraph (d)(1)(ii) to read as
follows:

Sec.  1066.815  Exhaust emission test procedures for FTP testing.

* * * * *
    (d) * * *
    (1) * * *
    (ii) Simultaneously start any electronic integrating devices,
continuous data recording, and batch sampling before attempting to
start the engine. Initiate the sequence of points in the test cycle
when the engine starts. Place the vehicle in gear 15 seconds after
engine starting, which is 5 seconds before the first acceleration.
* * * * *

0
277. Amend Sec.  1066.831 by revising paragraph (d) to read as follows:

Sec.  1066.831  Exhaust emission test procedures for aggressive
driving.

* * * * *
    (d) For diesel-fueled vehicles, measure THC emissions on a
continuous basis. For separate measurement of the city and highway test
intervals as described in paragraph (c) of this section, perform
separate calculations for each portion of the test cycle.
* * * * *

0
278. Amend Sec.  1066.835 by revising paragraphs (f)(1), (2), and
(f)(3)(iii) to read as follows:

Sec.  1066.835  Exhaust emission test procedure for SC03 emissions.

* * * * *
    (f) * * *
    (1) Ambient temperature and humidity. Measure and record ambient
temperature and humidity in the test cell at least once every 30
seconds during the sampling period. Alternatively, if you collect data
of at least once every 12 seconds, you may use a moving average of up
to 30 second intervals to measure and record ambient temperature and
humidity. Control ambient temperature throughout the test sequence to
(35.0  3.0)[deg]C. Control ambient temperature during
emission sampling to (33.6 to 36.4)[deg]C on average. Control ambient
humidity during emission sampling as described in Sec.  1066.420(d).
    (2) Conditions before testing. Use good engineering judgment to
demonstrate that you meet the specified temperature and humidity
tolerances in paragraph (f)(1) of this section during the
preconditioning cycle and during the vehicle soak period in paragraph
(c)(6) of this section.
    (3) * * *
    (iii) Determine radiant energy intensity experienced by the vehicle
as the average value between two measurements along the vehicle's
centerline, one at the base of the windshield and the other at the
bottom of the rear window (or equivalent location for vehicles without
a rear window). This value must be (850  45)

W/m\2\. Instruments for measuring radiant energy intensity must meet
the following minimum specifications:
* * * * *

0
279. Amend Sec.  1066.845 by revising paragraphs (c), (f)(3) and (g)
and adding paragraph (h) to read as follows:

Sec.  1066.845  AC17 air conditioning efficiency test procedure.

* * * * *
    (c) Ambient conditions. Measure and control ambient conditions as
specified in Sec.  1066.835(f), except that you must control ambient
temperature during emission sampling to (22.0 to 28.0)[deg]C throughout
the test and (23.5 to 26.5)[deg]C on average. These tolerances apply to
the combined SC03 and HFET drive cycles during emission sampling. Note
that you must set the same ambient temperature target for both the air
conditioning on and off portions of emission sampling. Control ambient
temperature during the preconditioning cycle and 30 minute soak to
(25.0  5.0)[deg]C. For these same modes with no emission
sampling, target the specified ambient humidity levels, but you do not
need to meet the humidity tolerances. Note that solar heating is
disabled for certain test intervals as described in this section.
* * * * *
    (f) * * *
    (3) Turn on solar heating within one minute after turning off the
engine. Once the solar energy intensity reaches 805 W/m\2\, let the
vehicle soak for (30  1) minutes. You may alternatively
rely on prior measurements to start the soak period after a defined
period of warming up to the specified solar heat load. Close the
vehicle's windows at the start of the soak period; ensure that the
windows are adequately closed where instrumentation and wiring pass
through to the interior.
* * * * *
    (g) Calculations. (1) Determine the mass of CO2
emissions for each of the two test intervals as described in Sec.
1066.605.
    (2) Calculate separate composite mass-weighted emissions of
CO2, eCO2-AC17compAC[status], representing the
average of the SC03 and HFET emissions, in grams per mile for operation
with the vehicle's air conditioner and the solar heating on and off
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR24JA23.162

Where:

mSC03 = mass emissions from the SC03 test interval, in
grams.
DSC03 = measured driving distance during the SC03 test
interval, in miles.
mHFET = mass emissions from the HFET test interval, in
grams.
DHFET = measured driving distance during the HFET test
interval, in miles.

    (3) Calculate the incremental CO2 emissions due to air
conditioning operation by subtracting the composite mass-weighted
emissions of CO2 with the vehicle's air conditioner and the
solar heating on, eCO2-AC17compACon, from the composite
mass-weighted emissions of CO2 with the vehicle's air
conditioner and the solar heating off, eCO2-AC17compACoff.
    (h) Record information for each test as specified in Sec.
1066.695. Emission results and the results of all calculations must be
reported for each phase of the test. The manufacturer must also report
the following information for each vehicle tested: interior volume,
climate control system type and characteristics, refrigerant used,
compressor type, and evaporator/condenser characteristics.

0
280. Amend Sec.  1066.1001 by adding definitions of ``Charge-
depleting'' and ``Charge-sustaining'' in alphabetical order and
revising the definition of ``Test interval'' to read as follows:

Sec.  1066.1001  Definitions.

* * * * *
    Charge-depleting means relating to the test interval of a plug-in
hybrid engine or powertrain in which the engine or powertrain consumes
electric energy from the RESS that has been charged from an external
power source until the RESS is depleted to the point that a test
interval qualifies as charge-sustaining. The engine might consume fuel
to produce power during a charge-depleting test interval.
    Charge-sustaining means relating to the test interval of a plug-in
hybrid engine or powertrain in which the engine or powertrain consumes
fuel to produce power such that the battery's net-energy change meets
the end-of-test criterion of SAE J1711 or SAE J2711, as applicable
(incorporated by reference in Sec.  1066.1010).
* * * * *
    Test interval means a period over which a vehicle's emission rates
are determined separately. For many standards, compliance with the
standard is based on a weighted average of the mass emissions from
multiple test intervals. For example, the standard-setting part may
specify a complete duty cycle as a cold-start test interval and a hot-
start test interval. In cases where multiple test intervals occur over
a duty cycle, the standard-setting part may specify additional
calculations that weight and combine results to arrive at composite
values for comparison against the applicable standards in this chapter.
* * * * *

0
281. Amend Sec.  1066.1005 by revising paragraphs (b), (g), and (h) to
read as follows:

Sec.  1066.1005  Symbols, abbreviations, acronyms, and units of
measure.

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

   Table 2 to Paragraph (b) of Sec.   1066.1005--Symbols for Chemical
                    Species and Exhaust Constituents
------------------------------------------------------------------------
                 Symbol                              Species
------------------------------------------------------------------------
CH4....................................  methane.
CH3OH..................................  methanol.
CH2O...................................  formaldehyde.
C2H4O..................................  acetaldehyde.
C2H5OH.................................  ethanol.
C2H6...................................  ethane.
C3H7OH.................................  propanol.

C3H8...................................  propane.
C4H10..................................  butane.
C5H12..................................  pentane.
CO.....................................  carbon monoxide.
CO2....................................  carbon dioxide.
H2O....................................  water.
HC.....................................  hydrocarbon.
N2.....................................  molecular nitrogen.
NMHC...................................  nonmethane hydrocarbon.
NMHCE..................................  nonmethane hydrocarbon
                                          equivalent.
NMOG...................................  nonmethane organic gas.
NO.....................................  nitric oxide.
NO2....................................  nitrogen dioxide.
NOX....................................  oxides of nitrogen.
N2O....................................  nitrous oxide.
O2.....................................  molecular oxygen.
OHC....................................  oxygenated hydrocarbon.
PM.....................................  particulate matter.
THC....................................  total hydrocarbon.
THCE...................................  total hydrocarbon equivalent.
------------------------------------------------------------------------

* * * * *
    (g) Constants. (1) This part uses the following constants for the
composition of dry air:

   Table 7 to Paragraph (g)(1) of Sec.   1066.1005--Constants for the
                         Composition of Dry Air
------------------------------------------------------------------------
              Symbol                      Quantity            mol/mol
------------------------------------------------------------------------
xArair............................  amount of argon in           0.00934
                                     dry air.
xCO2air...........................  amount of carbon            0.000375
                                     dioxide in dry air.
xN2air............................  amount of nitrogen           0.78084
                                     in dry air.
xO2air............................  amount of oxygen in         0.209445
                                     dry air.
------------------------------------------------------------------------

    (2) This part uses the following molar masses or effective molar
masses of chemical species:

    Table 8 to Paragraph (g)(2) of Sec.   1066.1005--Molar Masses or
               Effective Molar Masses of Chemical Species
------------------------------------------------------------------------
                                                       g/mol (10-
           Symbol                 Quantity     \3\[middot]kg[middot]mol-
                                                          \1\)
------------------------------------------------------------------------
Mair........................  molar mass of                28.96559
                               dry air \1\.
MH2O........................  molar mass of                18.01528
                               water.
------------------------------------------------------------------------
\1\ See paragraph (g)(1) of this section for the composition of dry air.

    (3) This part uses the following molar gas constant for ideal
gases:

               Table 9 to Paragraph (g)(3) of Sec.   1066.1005--Molar Gas Constant for Ideal Gases
----------------------------------------------------------------------------------------------------------------
                                                                                J/(mol[middot]K)
                                                                                (m\2\[middot]kg[middot]s-
                        Symbol                                     Quantity                 \2\[middot]mol-
                                                                                \1\[middot]K-\1\)
----------------------------------------------------------------------------------------------------------------
R.....................................................            molar gas constant              8.314472
----------------------------------------------------------------------------------------------------------------

    (h) Prefixes. This part uses the following prefixes to define a
quantity:

   Table 10 to Paragraph (h) of Sec.   1066.1005--Prefixes to Define a
                                Quantity
------------------------------------------------------------------------
              Symbol                      Quantity             Value
------------------------------------------------------------------------
n.................................  nano................          10-\9\
[mu]..............................  micro...............          10-\6\
m.................................  milli...............          10-\3\
c.................................  centi...............          10-\2\
k.................................  kilo................           10\3\
M.................................  mega................           10\6\
------------------------------------------------------------------------

0
282. Revise Sec.  1066.1010 to read as follows:

Sec.  1066.1010  Incorporation by reference.

    Certain material is incorporated by reference into this part with
the approval of the Director of the Federal Register under 5 U.S.C.
552(a) and 1 CFR part 51. To enforce any edition other than that
specified in this section, EPA must publish a document in the Federal
Register and the material must be available to the public. All approved
incorporation by reference (IBR) material is available for inspection
at EPA and at the National Archives and Records Administration (NARA).
Contact EPA at: U.S. EPA, Air and Radiation Docket Center, WJC West
Building, Room 3334, 1301 Constitution Ave. NW, Washington, DC 20004;
www.epa.gov/dockets;<PHONE_NUMBER>. For information on inspecting this
material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations.html or email [email protected]. The material may be
obtained from the following sources:

    (a) National Institute of Standards and Technology (NIST), 100
Bureau Drive, Stop 1070, Gaithersburg, MD 20899-1070;<PHONE_NUMBER>;
www.nist.gov.
    (1) NIST Special Publication 811, 2008 Edition, Guide for the Use
of the International System of Units (SI), Physics Laboratory, March
2008; IBR approved for Sec. Sec.  1066.20(a); 1066.1005.
    (2) [Reserved]
    (b) SAE International, 400 Commonwealth Dr., Warrendale, PA 15096-
0001;<PHONE_NUMBER> (U.S. and Canada) or<PHONE_NUMBER> (outside the
U.S. and Canada); www.sae.org.
    (1) SAE J1263 MAR2010, Road Load Measurement and Dynamometer
Simulation Using Coastdown Techniques, Revised March 2010, (``SAE
J1263''); IBR approved for Sec. Sec.  1066.301(b); 1066.305(a);
1066.310(b).
    (2) SAE J1634 JUL2017, Battery Electric Vehicle Energy Consumption
and Range Test Procedure, Revised July 2017, (``SAE J1634''); IBR
approved for Sec.  1066.501(a).
    (3) SAE J1711 JUN2010, Recommended Practice for Measuring the
Exhaust Emissions and Fuel Economy of Hybrid-Electric Vehicles,
Including Plug-In Hybrid Vehicles, Revised June 2010, (``SAE J1711'');
IBR approved for Sec. Sec.  1066.501(a); 1066.1001.
    (4) SAE J2263 DEC2008, Road Load Measurement Using Onboard
Anemometry and Coastdown Techniques, Revised December 2008; IBR
approved for Sec. Sec.  1066.301(b); 1066.305; 1066.310(b).
    (5) SAE J2263 MAY2020, (R) Road Load Measurement Using Onboard
Anemometry and Coastdown Techniques, Revised May 2020, (``SAE J2263'');
IBR approved for Sec. Sec.  1066.301(b); 1066.305; 1066.310(b).
    (6) SAE J2264 JAN2014, Chassis Dynamometer Simulation of Road Load
Using Coastdown Techniques, Revised January 2014, (``SAE J2264''); IBR
approved for Sec.  1066.315.
    (7) SAE J2711 MAY2020, (R) Recommended Practice for Measuring Fuel
Economy and Emissions of Hybrid-Electric and Conventional Heavy-Duty
Vehicles, Revised May 2020, (``SAE J2711''); IBR approved for
Sec. Sec.  1066.501(a); 1066.1001.
    (8) SAE J2951 JAN2014, Drive Quality Evaluation for Chassis
Dynamometer Testing, Revised January 2014, (``SAE J2951''); IBR
approved for Sec.  1066.425(j).

PART 1068--GENERAL COMPLIANCE PROVISIONS FOR HIGHWAY, STATIONARY,
AND NONROAD PROGRAMS

0
283. The authority citation for part 1068 continues to read as follows:

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

0
284. Amend Sec.  1068.1 by revising paragraphs (a)(2), (4), (5), (6),
(8), (9), and (13) and adding paragraph (a)(15) to read as follows:

Sec.  1068.1  Does this part apply to me?

    (a) * * *
    (2) This part 1068 applies for heavy-duty motor vehicles and motor
vehicle engines we regulate under 40 CFR parts 1036 and 1037. This
includes trailers. This part 1068 applies to heavy-duty motor vehicles
and motor vehicle engines certified under 40 CFR part 86 to the extent
and in the manner specified in 40 CFR parts 85, 86, and 1036.
* * * * *
    (4) This part applies to aircraft and aircraft engines we regulate
under 40 CFR parts 1030 and 1031 to the extent and in the manner
specified in 40 CFR parts 1030 and 1031.
    (5) This part 1068 applies for locomotives that are subject to the
provisions of 40 CFR part 1033.
    (6) This part 1068 applies for land-based nonroad compression-
ignition engines that are subject to the provisions of 40 CFR part
1039. This part 1068 applies for engines certified under 40 CFR part 89
to the extent and in the manner specified in 40 CFR part 1039.
* * * * *
    (8) This part 1068 applies for marine compression-ignition engines
that are subject to the provisions of 40 CFR part 1042. This part 1068
applies for marine compression-ignition engines certified under 40 CFR
part 94 to the extent and in the manner specified in 40 CFR part 1042.
    (9) This part 1068 applies for marine spark-ignition engines that
are subject to the provisions of 40 CFR part 1045. This part 1068
applies for marine spark-ignition engines certified under 40 CFR part
91 to the extent and in the manner specified in 40 CFR part 1045.
* * * * *
    (13) This part applies for small nonroad spark-ignition engines
that are subject to the provisions of 40 CFR part 1054. This part 1068
applies for nonroad spark-ignition engines certified under 40 CFR part
90 to the extent and in the manner specified in 40 CFR part 1054.
* * * * *
    (15) This part 1068 applies to portable fuel containers we regulate
under 40 CFR part 59 to the extent and in the manner specified in 40
CFR part 59, subpart F.
* * * * *

0
285. Revise Sec.  1068.10 to read as follows:

Sec.  1068.10  Practices for handling confidential business
information.

    The provisions of this section apply both to any information you
send us and to any information we collect from inspections, audits, or
other site visits.
    (a) When you submit information to us, if you claim any of that
information as confidential, you may identify what you claim to be
confidential by marking, circling, bracketing, stamping, or some other
method; however, we will not consider any claims of confidentiality
over information we have determined to be not entitled to confidential
treatment under Sec.  1068.11 or other applicable provisions.
    (b) If you send us information without claiming it is confidential,
we may make it available to the public without further notice to you,
as described in 40 CFR 2.301(j).
    (c) For submissions that include information that may be entitled
to confidential treatment, we may require that you send a ``public''
copy of the report that does not include the confidential information.
We may require that you substantiate your claim to confidential
treatment for any items not contained in the public version. We will
release additional information from the complete version of such a
submission only as allowed under 40 CFR 2.301(j) and as described in
this subpart and the standard-setting part.
    (d) We will safeguard your confidential business information (CBI)
as described in 40 CFR 2.301(j). Also, we will treat certain
information as confidential and will only disclose this information if
it has been determined to be not entitled to confidential treatment as
specified in Sec.  1068.11(c). The following general provisions
describe how we will process requests for making information publicly
available:
    (1) Certification information. We will treat information submitted
in an application for certification as confidential until the
introduction-into-commerce date you identify in your application for
certification consistent with 40 CFR 2.301(a)(2)(ii)(B). If you do not
identify an introduction-into-commerce date or if we issue the
certificate after your specified date, we will treat information
submitted in an application for certification as described in Sec.
1068.11 after the date we issue the certificate.
    (2) Preliminary and superseded information. Preliminary and
superseded versions of information you submit are covered by
confidentiality determinations in the same manner as

final documents. However, we will generally not disclose preliminary or
superseded information unless we receive a request under 5 U.S.C. 552
that specifically asks for all versions of a document, including
preliminary and superseded versions. We will consider a document
preliminary if we have not reviewed it to verify its accuracy or if the
reporting deadline has not yet passed. We will consider information
superseded if you submit a new document or a revised application for
certification to replace the earlier version.
    (3) Authorizing CBI disclosure. The provisions of this section do
not prevent us from disclosing protected information if you
specifically authorize it.
    (4) Relationship to the standard-setting part. The standard-setting
part may identify additional provisions related to confidentiality
determinations. Note that the standard-setting part identifies
information requirements that apply for each type of engine/equipment.
If this section identifies information that is not required for a given
engine, that does not create a requirement to submit the information.
    (5) Changes in law. The confidentiality determinations in this
section and in the standard-setting parts may be changed through the
processes described in 40 CFR 2.301(j)(4).

0
286. Add Sec.  1068.11 to subpart A to read as follows:

Sec.  1068.11  Confidentiality determinations and related procedures.

    This section characterizes various categories of information for
purposes of making confidentiality determinations, as follows:
    (a) This paragraph (a) applies the definition of ``Emission data''
in 40 CFR 2.301(a) for information related to engines/equipment subject
to this part. ``Emission data'' cannot be treated as confidential
business information and shall be available to be disclosed to the
public except as specified in Sec.  1068.10(d)(1). The following
categories of information qualify as emission data, except as specified
in paragraph (c) of this section:
    (1) Certification and compliance information, including information
submitted in an application for a certificate of conformity that is
used to assess compliance.
    (2) Fleet value information, including information submitted for
compliance with fleet average emission standards and emissions related
ABT credit information, including the information used to generate
credits.
    (3) Source family information. For example, engine family
information or test group information would identify the regulated
emission source.
    (4) Test information and results, including emission test results
and other data from emission testing that are submitted in an
application for a certificate of conformity, test results from in-use
testing, production-line testing, and any other testing to demonstrate
emissions. The information in this category includes all related
information to characterize test results, document the measurement
procedure, and modeling inputs and outputs where the compliance
demonstration is based on computer modeling.
    (5) ABT credit information, including information submitted for
current and future compliance demonstrations using credits under an ABT
program.
    (6) Production volume, including information submitted for
compliance with fleet average emission standards, compliance with
requirements to test production engines/equipment, or compliance
through ABT programs.
    (7) Defect and recall information, including all information
submitted in relation to a defect or recall except the remedial steps
you identify in Sec.  1068.510(a)(2).
    (8) Selective enforcement audit compliance information.
    (b) The following categories of information are not eligible for
confidential treatment, except as specified in Sec.  1068.10(d)(1):
    (1) Published information, including information that is made
available in annual and quarterly filings submitted to the U.S.
Securities and Exchanges Commission, on company websites, or otherwise
made publicly available by the information submitter.
    (2) Observable information available to the public after the
introduction to commerce date.
    (c) The following categories of information are subject to the
process for confidentiality determinations in 40 CFR part 2 as
described in 40 CFR 2.301(j)(5):
    (1) Projected sales volume and projected production volume.
    (2) Production start and end dates.
    (3) Detailed description of emission control operation and
function.
    (4) Design specifications related to aftertreatment devices.
    (5) Description of auxiliary emission control devices (AECDs).
    (6) Plans for meeting regulatory requirements. For example, this
applies for any projections of emission credits for the coming model
year or determinations of the number of required repair facilities that
are based on projected production volumes.
    (7) The following information related to deterioration factors and
other adjustment factors:
    (i) Procedures to determine deterioration factors and other
emission adjustment factors.
    (ii) Any information used to justify those procedures.
    (iii) Emission measurements you use to compare procedures or
demonstrate that the procedures are appropriate.
    (8) Financial information related to the following items:
    (i) ABT credit transactions, including dollar amount, identity of
parties, and contract information.
    (ii) Meeting bond requirements, including aggregate U.S. asset
holdings, financial details regarding specific assets, whether the
manufacturer or importer obtains a bond, and copies of bond policies.
    (9) Serial numbers or other information to identify specific
engines or equipment selected for testing.
    (10) Procedures that apply based on your request to test engines/
equipment differently than we specify in the regulation. This applies
for special and alternative test procedures. This also applies, for
example, if we approve a broader or narrower zone of engine operation
for not-to-exceed testing.
    (11) Information related to testing vanadium catalysts in 40 CFR
part 1065, subpart L.
    (12) GPS data identifying the location for in-use emission
measurements.
    (13) Information related to possible defects that are subject to
further investigation (not confirmed defects).
    (14) Information submitted in support of a requested exemption.
    (d) If you submit information that is not addressed in paragraphs
(a) through (c) of this section, you may claim the information as
confidential. We may require you to provide us with information to
substantiate your claims. If claimed, we may consider this
substantiating information to be confidential to the same degree as the
information for which you are requesting confidential treatment. We
will make our determination based on your statements to us, the
supporting information you send us, and any other available
information. However, we may determine that your information is not
subject to confidential treatment consistent with 40 CFR part 2 and 5
U.S.C. 552(b)(4).
    (e) Applications for certification and submitted reports typically
rely on software or templates to identify specific categories of
information. If you submit information in a comment field

designated for users to add general information, we will respond to
requests for disclosing that information consistent with paragraphs (a)
through (d) of this section.

0
287. Amend Sec.  1068.30 by adding a definition of ``Critical emission-
related component'' in alphabetical order and revising the definition
of ``Designated Compliance Officer'' to read as follows:

Sec.  1068.30  Definitions.

* * * * *
    Critical emission-related component means a part or system whose
primary purpose is to reduce emissions or whose failure would commonly
increase emissions without significantly degrading engine/equipment
performance.
* * * * *
    Designated Compliance Officer means one of the following:
    (1) For motor vehicles regulated under 40 CFR part 86, subpart S:
Director, Light-Duty Vehicle Center, U.S. Environmental Protection
Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
[email protected]; www.epa.gov/ve-certification.
    (2) For compression-ignition engines used in heavy-duty highway
vehicles regulated under 40 CFR part 86, subpart A, and 40 CFR parts
1036 and 1037, and for nonroad and stationary compression-ignition
engines or equipment regulated under 40 CFR parts 60, 1033, 1039, and
1042: Director, Diesel Engine Compliance Center, U.S. Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
[email protected]; www.epa.gov/ve-certification.
    (3) Director, Gasoline Engine Compliance Center, U.S. Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
[email protected]; www.epa.gov/ve-certification, for all the
following engines and vehicles:
    (i) For spark-ignition engines used in heavy-duty highway vehicles
regulated under 40 CFR part 86, subpart A, and 40 CFR parts 1036 and
1037,
    (ii) For highway motorcycles regulated under 40 CFR part 86,
subpart E.
    (iii) For nonroad and stationary spark-ignition engines or
equipment regulated under 40 CFR parts 60, 1045, 1048, 1051, 1054, and
1060.

0
288. Add Sec.  1068.50 to subpart A to read as follows:

Sec.  1068.50  Adjustable parameters.

    (a) The standard-setting part requires as a condition of
certification that engines with adjustable parameters meet all the
requirements of the standard-setting part for any setting in the
practically adjustable range. This section defines these terms and
describes general provisions that apply broadly across sectors. This
section refers to engines, because most adjustable parameters are
integral to the engine even in the case of equipment-based standards;
this section also applies for equipment-based adjustable parameters.
The provisions of this section apply starting with model year 2027 and
are optional for earlier model years.
    (b) You must use good engineering judgment for all decisions
related to adjustable parameters. We recommend that you ask for
preliminary approval for decisions related to new technologies,
substantially changed engine designs, or new methods for limiting
adjustability. The standard-setting part describes the information you
must include in the application for certification related to adjustable
parameters. Decisions related to adjustable parameters include the
following:
    (1) Determining which engine operating parameters qualify as
adjustable parameters.
    (2) Establishing the adequacy of the limits, stops, seals,
programming limits, inducements, or other means used to limit
adjustment, limit reprogramming, or ensure replenishment.
    (3) Defining the practically adjustable range for each such
parameter.
    (c) For purposes of this section, ``operating parameter'' means any
feature that can, by the nature of its design, be adjusted to affect
engine performance. For example, while bolts used to assemble the
engine are practically adjustable (can be loosened or tightened), they
are not adjustable parameters because they are not operating
parameters. Consider all programmable parameters not involving user-
selectable controls to be a single, collective operating parameter.
    (d) Operating parameters are considered adjustable parameters if
they are practically adjustable by a user or other person by physical
adjustment, programmable adjustment, or regular replenishment of a
fluid or other consumable material. However, an operating parameter is
not an adjustable parameter if--
    (1) We determine it is permanently sealed or it is not practically
adjustable using available tools, as described in paragraph (e) of this
section; or
    (2) We determine that engine operation over the full range of
adjustment does not affect emissions without also degrading engine
performance to the extent that operators will be aware of the problem.
    (e) An operating parameter is considered practically adjustable as
follows:
    (1) Physically adjustable parameters are considered practically
adjustable if the adjustment is accessible and can be performed by an
experienced mechanic using appropriate tools within the following time
and cost thresholds, excluding extraordinary measures:
    (i) For engines at or below 30 kW, physically adjustable parameters
are considered practically adjustable if a typical user can make
adjustments with ordinary tools within 15 minutes using service parts
that cost no more than $30.
    (ii) For 30-560 kW engines, physically adjustable parameters are
considered practically adjustable if a qualified mechanic can make
adjustments with ordinary tools within 60 minutes using service parts
that cost no more than $60.
    (iii) For engines above 560 kW, physically adjustable parameters
are considered practically adjustable if a qualified mechanic can make
adjustments with any available supplies and tools within 60 minutes.
    (iv) Cost thresholds in this section are expressed in 2020 dollars.
Adjust these values for certification by comparing most recently
available Consumer Price Index for All Urban Consumers (CPI-U) value
published by the Bureau of Labor Statistics at www.bls.gov/data/inflation_calculator.htm.
    (v) Cost thresholds do not include the cost of labor or the cost of
any necessary tools or nonconsumable supplies. Time thresholds refer to
the time required to access and adjust the parameter, excluding any
time necessary to purchase parts, tools, or supplies, or to perform
testing.
    (vi) The term ``ordinary tools'' has the following meanings for
different sizes of engines:
    (A) Ordinary tools consist of slotted and Phillips head
screwdrivers, pliers, hammers, awls, wrenches, electric screwdrivers,
electric drills, and any tools supplied by the manufacturer, where
those tools are used for their intended purpose.
    (B) For 30-560 kW engines, ordinary tools includes the tools
identified in paragraph (e)(1)(vi)(A) of this section and any other
hand tools, solvents, or other supplies sold at hardware stores,
automotive parts supply stores or on the internet.
    (vii) The following extraordinary measures are not included when
determining whether a physically adjustable parameter is considered

``practically adjustable'' according to the specified time and cost
thresholds:
    (A) Removing the cylinder head(s) from the engine block.
    (B) Fully or partially removing a carburetor.
    (C) Drilling or grinding through caps or plugs.
    (D) Causing damage to engine or equipment if the associated repair
would exceed the time or cost thresholds in this paragraph (e)(1).
    (E) Making special tools to override design features that prevent
adjustment. Note that extraordinary measures do not include purchase of
such special tools if they become available as described in paragraph
(e)(1)(vi)(B) of this section.
    (2) A programmable operating parameter is considered ``practically
adjustable'' if an experienced mechanic can adjust the parameter using
any available tools (including devices that are used to alter computer
code). Conversely, such parameters are not practically adjustable if
you limit access to electronic control modules with password or
encryption protection. You must have adequate protections in place to
prevent distribution and use of passwords or encryption keys. This
paragraph (e)(2) applies for engines with any degree of programmable
control. Programmable settings are considered practically adjustable if
any of the following apply:
    (i) The user can make the adjustment by following instructions in
the owners manual.
    (ii) An experienced mechanic can make the adjustment using ordinary
digital interface tools for selecting available settings or options as
described in this paragraph (e)(2).
    (f) The practically adjustable range for physically adjustable
operating parameters is based on design features to create physical
limits or stops to limit adjustment. A physical limit or stop is
adequate for defining the limits of the practically adjustable range if
it has the following characteristics:
    (1) In the case of a threaded adjustment, the head is sheared off
after adjustment at the factory or the threads are terminated, pinned,
or crimped to prevent additional travel without causing damage for
which the repair would exceed the time or cost thresholds in paragraph
(e)(1) of this section.
    (2) In the case of fasteners, bimetal springs, or other mechanical
devices used to limit adjustment, those devices are recessed within a
larger, permanent body and sealed with a plug, cap, or cover plate that
limits access to the device consistent with the time and cost
thresholds in paragraph (e)(1) of this section.
    (3) Operators cannot exceed the travel or rotation limits using
appropriate tools without causing damage for which the repairs would
exceed the time or cost thresholds specified in paragraph (e)(1) of
this section. For example, if a vehicle has a shim, bushing, or other
device to limit flow rates, range of travel, or other parameters to
prevent operating outside of a specified range of engine or vehicle
speeds, you must take steps to prevent operators or mechanics from
removing, replacing, or altering those parts to operate at a wider
range of engine or vehicle speeds.
    (g) Apply the following provisions to determine the practically
adjustable range for programmable parameters that can be adjusted by
changing software or operating parameters (``reflashed''):
    (1) If an engine includes multiple operating modes or other
algorithms that can be selected or are easily accessible, consider each
of the selectable or accessible modes or settings to be within the
practically adjustable range.
    (2) If you sell or offer to sell software or other tools that an
experienced mechanic not affiliated with the manufacturer could use to
reflash or otherwise modify the electronic control module, consider all
those settings to be within the practically adjustable range.
    (3) The following systems and features illustrate examples of the
types of programmable settings for which this paragraph (g) applies:
    (i) Air-fuel setpoints for closed-loop fuel systems.
    (ii) Reductant flow systems.
    (iii) Base maps for fuel injection or spark timing.
    (iv) Exhaust gas recirculation maps.
    (h) The following provisions apply for adjustable parameters
related to elements of design involving consumption and replenishment,
such as DEF tank fill level and hybrid battery state of charge:
    (1) We will determine the range of adjustability based on the
likelihood of in-use operation at a given point in the physically
adjustable range. We may determine that operation in certain subranges
within the physically adjustable range is sufficiently unlikely that
the subranges should be excluded from the allowable adjustable range
for testing. In such cases, the engines/equipment are not required to
meet the emission standards for operation in an excluded subrange.
    (2) Shipping new engines/equipment in a state or configuration
requiring replenishment to be within the range of adjustability for a
certified configuration does not cause a violation of the prohibition
in Sec.  1068.101(a)(1).
    (i) We will make determinations regarding in-use adjustments of
adjustable parameters under this section for certifying engines as
follows:
    (1) Our determinations will depend on in-use maintenance practices
conforming to the maintenance and service information you provide. For
example, if your published maintenance instructions describe routine
procedures for adjusting engines or if you or your dealers make
specialized tools available to operators, we will conclude that such
adjustments are likely to occur. Also, your maintenance and service
information may not specify adjustable ranges that are broader than
those that you specify in your application for certification.
    (2) We may review manufacturer statements under this section for
certifying engines for a later model year if we learn from observation
of in-use engines or other information that a parameter was in fact
practically adjustable or that the specified operating range was in
fact not correct. We may require you to include a new adjustable
parameter or to revise your specified operating range for an adjustable
parameter.
    (j) We may inspect your engines at any time to determine whether
they meet the specifications of this section. We may purchase engines
for testing, or we may ask you to supply engines for such inspections.
We will inspect using appropriate tools and time limits and using any
available devices that alter computer code, as specified in paragraph
(e)(2) of this section. The inspection will determine the following:
    (1) If the adjustable parameter is limited to the adjustable range
specified in the manufacturer's certification application.
    (2) If physical stops for physically adjustable parameters can be
bypassed using methods outlined in paragraph (f) of this section.
    (k) Except as provided in the standard-setting part and this
paragraph (k), engines are not in the certified configuration if you
produce them with adjustable parameters set outside the range specified
in your application for certification. Similarly, engines are not in
the certified configuration if you produce them with other operating
parameters that do not conform to the certified configuration. Where we
determine that you failed to identify something that should be
considered an adjustable parameter, we may require you to treat the
parameter as defective under Sec.  1068.501. If we determine you
deliberately misrepresented the

accessibility of the parameter or that you did not act in good faith,
we may take action regarding your certificate as described in the
standard-setting part (see, for example, 40 CFR 1054.255).
    (l) Nothing in this section limits the tampering prohibition of
Sec.  1068.101(b)(1) or the defeat device prohibition of Sec.
1068.101(b)(2).

0
289. Amend Sec.  1068.101 by revising paragraphs (a) introductory text
and (b)(5) to read as follows:

Sec.  1068.101  What general actions does this regulation prohibit?

* * * * *
    (a) The following prohibitions and requirements apply to
manufacturers of new engines, manufacturers of equipment containing
these engines, manufacturers of new equipment, and other persons as
provided by Sec.  1068.1(a), except as described in subparts C and D of
this part:
* * * * *
    (b) * * *
    (5) Importation. You may not import an uncertified engine or piece
of equipment if it is defined to be new in the standard-setting part
with a model year for which emission standards applied. Anyone
violating this paragraph (b)(5) is deemed to be a manufacturer in
violation of paragraph (a)(1) of this section. We may assess a civil
penalty up to $44,539 for each engine or piece of equipment in
violation. Note the following:
* * * * *

0
290. Amend Sec.  1068.210 by revising paragraph (c) introductory text
to read as follows:

Sec.  1068.210  Exempting test engines/equipment.

* * * * *
    (c) If you are a certificate holder, you may request an exemption
for engines/equipment you intend to include in a test program.
* * * * *

0
291. Amend Sec.  1068.220 by revising paragraph (b) to read as follows:

Sec.  1068.220  Exempting display engines/equipment.

* * * * *
    (b) Nonconforming display engines/equipment will be exempted if
they are used for displays in the interest of a business or the general
public. The exemption in this section does not apply to engines/
equipment displayed for any purpose we determine is inappropriate for a
display exemption.
* * * * *

0
292. Amend Sec.  1068.240 by revising paragraphs (a)(1), (b)(3), and
(c)(3)(ii) to read as follows:

Sec.  1068.240  Exempting new replacement engines.

* * * * *
    (a) * * *
    (1) Paragraphs (b) and (c) of this section describe different
approaches for exempting new replacement engines where the engines are
specially built to correspond to an engine model from an earlier model
year that was subject to less stringent standards than those that apply
for current production (or is no longer covered by a certificate of
conformity). You must comply with the requirements of paragraph (b) of
this section for any number of replacement engines you produce in
excess of what we allow under paragraph (c) of this section. You must
designate engines you produce under this section as tracked engines
under paragraph (b) of this section or untracked engines under
paragraph (c) of this section by the deadline for the report specified
in paragraph (c)(3) of this section.
* * * * *
    (b) * * *
    (3) An old engine block replaced by a new engine exempted under
this paragraph (b) may be reintroduced into U.S. commerce as part of an
engine that meets either the current standards for new engines, the
provisions for new replacement engines in this section, or another
valid exemption. Otherwise, you must destroy the old engine block (or
confirm that it has been destroyed), or export the engine block without
its emission label. Note that this paragraph (b)(3) does not require
engine manufacturers to take possession of the engine being replaced.
Owners may arrange to keep the old engine if they demonstrate that the
engine block has been destroyed. An engine block is destroyed under
this paragraph (b)(3) if it can never be restored to a running
configuration.
* * * * *
    (c) * * *
    (3) * * *
    (ii) Count exempt engines as tracked under paragraph (b) of this
section only if you meet all the requirements and conditions that apply
under paragraph (b)(2) of this section by the due date for the annual
report. In the annual report you must identify any replaced engines
from the previous year whose final disposition is not resolved by the
due date for the annual report. Continue to report those engines in
later reports until the final disposition is resolved. If the final
disposition of any replaced engine is not resolved for the fifth annual
report following the production report, treat this as an untracked
replacement in the fifth annual report for the preceding year.
* * * * *

0
293. Amend Sec.  1068.261 by revising paragraphs (b), (c) introductory
text, and (d) introductory text to read as follows:

Sec.  1068.261  Delegated assembly and other provisions related to
engines not yet in the certified configuration.

* * * * *
    (b) If you manufacture engines and install them in equipment you or
an affiliated company also produce, you must take steps to ensure that
your facilities, procedures, and production records are set up to
ensure that equipment and engines are assembled in their proper
certified configurations. For example, you may demonstrate compliance
with the requirements of this section by maintaining a database showing
how you pair aftertreatment components with the appropriate engines
such that the final product is in its certified configuration.
    (c) If you manufacture engines and ship them to an unaffiliated
company for installation in equipment and you include the price of all
aftertreatment components in the price of the engine (whether or not
you ship the aftertreatment components directly to the equipment
manufacturer), all the following conditions apply:
* * * * *
    (d) If you manufacture engines and ship them to an unaffiliated
company for installation in equipment, but you do not include the price
of all aftertreatment components in the price of the engine, you must
meet all the conditions described in paragraphs (c)(1) through (9) of
this section, with the following additional provisions:
* * * * *

0
294. Amend Sec.  1068.301 by revising paragraph (b) to read as follows:

Sec.  1068.301  General provisions for importing engines/equipment.

* * * * *
    (b) In general, engines/equipment that you import must be covered
by a certificate of conformity unless they were built before emission
standards started to apply. This subpart describes the limited cases
where we allow importation of exempt or excluded engines/equipment. If
an engine has an exemption from exhaust emission standards, you may
import the equipment under the same exemption. Imported engines/
equipment that are exempt or excluded must have a label as described in
the specific exemption

or exclusion. If the regulation does not include specific labeling
requirements, apply a label meeting the requirements of Sec.  1068.45
that identifies your corporate name and describes the basis for the
exemption or exclusion.
* * * * *

0
295. Amend Sec.  1068.310 by revising the introductory text and
paragraph (e)(4) to read as follows:

Sec.  1068.310  Exclusions for imported engines/equipment.

    If you show us that your engines/equipment qualify under one of the
paragraphs of this section, we will approve your request to import such
excluded engines/equipment. You must have our approval before importing
engines/equipment under paragraph (a) of this section. You may, but are
not required, to request our approval to import the engines/equipment
under paragraph (b) through (d) of this section. Qualifying engines/
equipment are excluded as follows:
* * * * *
    (e) * * *
    (4) State: ``THIS ENGINE IS EXEMPT FROM THE REQUIREMENTS OF
[identify the part referenced in Sec.  1068.1(a) that would otherwise
apply], AS PROVIDED IN [identify the paragraph authorizing the
exemption (for example, ``40 CFR 1068.310(a)'')]. INSTALLING THIS
ENGINE IN ANY DIFFERENT APPLICATION MAY BE A VIOLATION OF FEDERAL LAW
SUBJECT TO CIVIL PENALTY.''

0
296. Amend Sec.  1068.315 by revising paragraphs (a) and (h) and
removing paragraph (i) to read as follows:

Sec.  1068.315  Permanent exemptions for imported engines/equipment.

* * * * *
    (a) National security exemption. You may import an engine or piece
of equipment under the national security exemption in Sec.  1068.225.
* * * * *
    (h) Identical configuration exemption. Unless specified otherwise
in the standard-setting part, you may import nonconforming engines/
equipment if they are identical in all material respects to certified
engines/equipment produced by the same manufacturer, subject to the
following provisions:
    (1) You must meet all the following criteria:
    (i) You have owned the engines/equipment for at least six months.
    (ii) You agree not to sell, lease, donate, trade, or otherwise
transfer ownership of the engines/equipment for at least five years.
The only acceptable way to dispose of the engines/equipment during this
five-year period is to destroy or export them.
    (iii) You use data or evidence sufficient to show that the engines/
equipment are in a configuration that is identical in all material
respects to engines/equipment the original manufacturer has certified
to meet emission standards that apply at the time the manufacturer
finished assembling or modifying the engines/equipment in question. If
you modify the engines/equipment to make them identical, you must
completely follow the original manufacturer's written instructions.
    (2) We will tell you in writing if we find the information
insufficient to show that the engines/equipment are eligible for the
identical configuration exemption. We will then not consider your
request further until you address our concerns.

0
297. Amend Sec.  1068.325 by revising the introductory text, paragraphs
(a) through (c), (e), and (g) to read as follows:

Sec.  1068.325  Temporary exemptions for imported engines/equipment.

    You may import engines/equipment under certain temporary
exemptions, subject to the conditions in this section. We may ask U.S.
Customs and Border Protection to require a specific bond amount to make
sure you comply with the requirements of this subpart. You may not sell
or lease one of these exempted engines/equipment while it is in the
United States except as specified in this section or Sec.  1068.201(i).
You must eventually export the engine/equipment as we describe in this
section unless it conforms to a certificate of conformity or it
qualifies for one of the permanent exemptions in Sec.  1068.315 or the
standard-setting part.
    (a) Exemption for repairs or alterations. You may temporarily
import nonconforming engines/equipment solely for repair or alteration,
subject to our advance approval as described in paragraph (j) of this
section. You may operate the engine/equipment in the United States only
as necessary to repair it, alter it, or ship it to or from the service
location. Export the engine/equipment directly after servicing is
complete, or confirm that it has been destroyed.
    (b) Testing exemption. You may temporarily import nonconforming
engines/equipment for testing if you follow the requirements of Sec.
1068.210, subject to our advance approval as described in paragraph (j)
of this section. You may operate the engines/equipment in the United
States only as needed to perform tests. The testing exemption expires
one year after you import the engine/equipment unless we approve an
extension. The engine/equipment must be exported before the exemption
expires. You may sell or lease the engines/equipment consistent with
the provisions of Sec.  1068.210.
    (c) Display exemption. You may temporarily import nonconforming
engines/equipment for display if you follow the requirements of Sec.
1068.220, subject to our advance approval as described in paragraph (j)
of this section. The display exemption expires one year after you
import the engine/equipment, unless we approve your request for an
extension. The engine/equipment must be exported (or destroyed) by the
time the exemption expires or directly after the display concludes,
whichever comes first.
* * * * *
    (e) Diplomatic or military exemption. You may temporarily import
nonconforming engines/equipment if you represent a foreign government
in a diplomatic or military capacity. U.S Customs and Border Protection
may require that you show your written confirmation from the U.S. State
Department that you qualify for the diplomatic or military exemption or
a copy of your orders for military duty in the United States. We will
rely on the State Department or your military orders to determine when
your diplomatic or military status expires, at which time you must
export your exempt engines/equipment.
* * * * *
    (g) Exemption for partially complete engines. The following
provisions apply for importing partially complete engines and used
engines that become new as a result of importation:
    (1) You may import a partially complete engine by shipping it from
one of your facilities to another under the provisions of Sec.
1068.260(c) if you also apply a removable label meeting the
requirements of Sec.  1068.45 that identifies your corporate name and
states that the engine is exempt under the provisions of Sec.
1068.325(g).
    (2) You may import an engine if another company already has a
certificate of conformity and will be modifying the engine to be in its
final certified configuration or a final exempt configuration if you
meet the labeling and other requirements of Sec.  1068.262. If you are
importing a used engine that becomes new as a result of importation,
you must meet all the requirements that apply to original engine
manufacturers under Sec.  1068.262. You may sell or lease

the engines consistent with the provisions of Sec.  1068.262.
* * * * *

0
298. Amend Sec.  1068.450 by revising paragraph (e) to read as follows:

Sec.  1068.450  What records must I send to EPA?

* * * * *
    (e) We may post test results on publicly accessible databases and
we will send copies of your reports to anyone from the public who asks
for them, consistent with Sec.  1068.11.

0
299. Amend Sec.  1068.601 by revising the introductory text and
paragraph (b) to read as follows:

Sec.  1068.601  Overview.

    The regulations of this chapter involve numerous provisions that
may result in EPA making a decision or judgment that you may consider
adverse to your interests. For example, our decisions might require you
to pay penalties, or you might consider that our decisions will limit
your business activities or put you at a competitive disadvantage. As
specified in the regulations in this chapter, this might involve an
opportunity for an informal hearing or a formal hearing that follows
specific procedures and is directed by a Presiding Officer. The
regulations in this chapter generally specify when we would hold a
hearing. In limited circumstances, we may grant a request for a hearing
related to adverse decisions regarding regulatory provisions for which
we do not specifically describe the possibility of asking for a
hearing.
* * * * *
    (b) For other issues where the regulation allows for a hearing in
response to an adverse decision, you may request an informal hearing as
described in Sec.  1068.650. Sections 1068.610 through 1068.630
describe when and how to request an informal hearing under various
circumstances.
* * * * *

0
300. Add Sec.  1068.630 to read as follows:

Sec.  1068.630  Request for hearing--allowable maintenance.

    (a) Any manufacturer may request an informal hearing as described
in Sec.  1068.650 in response to our decision to identify allowable
maintenance associated with new technology as part of the certification
process.
    (b) You must send your hearing request in writing to the Designated
Compliance Officer no later than 30 days after we publish our decision
in the Federal Register. If the deadline passes, we may nevertheless
grant you a hearing at our discretion.
    (c) Your hearing request must include the information specified in
Sec.  1068.610(d).
    (d) We will approve your request for an informal hearing if we find
that your request raises a substantial factual issue in the decision we
made that, if addressed differently, could alter the outcome of that
decision.

0
301. Redesignate appendix I to part 1068 as appendix A to part 1068 and
amend newly redesignated appendix A by revising the introductory text
and paragraph IV to read as follows:

Appendix A to Part 1068--Emission-Related Components

    This appendix specifies emission-related components that we
refer to for describing such things as emission-related warranty or
maintenance or requirements related to rebuilding engines. Note that
inclusion of a component in Section III of this Appendix does not
make it an emission-related component for engines/equipment that are
not subject to evaporative emission standards.
* * * * *
    IV. Any other part or system that meets the definition of critical
emission-related component.

Appendix II to Part 1068 [Redesignated as Appendix B to Part 1068]

0
302. Redesignate appendix II to part 1068 as appendix B to part 1068.

Appendix III to Part 1068 [Redesignated as Appendix C to Part 1068]

0
303. Redesignate appendix III to part 1068 as appendix C to part 1068.

PART 1090--REGULATION OF FUELS, FUEL ADDITIVES, AND REGULATED
BLENDSTOCKS

0
304. The authority citation for part 1090 continues to read as follows:

    Authority: 42 U.S.C. 7414, 7521, 7522-7525, 7541, 7542, 7543,
7545, 7547, 7550, and 7601.

Subpart P [Amended]

0
305. Revise Sec.  1090.1550 to read as follows:

Sec.  1090.1550  Requirements for gasoline dispensing nozzles used with
motor vehicles.

    The following requirements apply for any nozzle installation used
for dispensing gasoline into motor vehicles:
    (a) Nozzles must meet the following hardware specifications:
    (1) The outside diameter of the terminal end must not be greater
than 21.3 mm.
    (2) The terminal end must have a straight section of at least 63
mm.
    (3) The retaining spring must terminate at least 76 mm from the
terminal end.
    (b) The dispensing flow rate must not exceed a maximum value of 10
gallons per minute. The flow rate may be controlled through any means
in the pump/dispenser system, as long as it does not exceed the
specified maximum value.

[FR Doc. 2022-27957 Filed 1-11-23; 4:15 pm]
 BILLING CODE 6560-50-P