above nhi per Sec.  1065.610(c)(2).
    (d) Mapping constant-speed engines. For constant-speed engines,
generate a map as follows:
    (1) Record the atmospheric pressure.
    (2) Warm up the engine by operating it. We recommend operating the
engine at approximately 75% of the engine's expected maximum power.
Continue the warm-up until the engine coolant, block, or head absolute
temperature is within 2% of its mean value for at least 2
min or until the engine thermostat controls engine temperature.
    (3) You may operate the engine with a production constant-speed
governor or simulate a constant-speed governor by controlling engine
speed with an operator demand control system described in Sec.
1065.110. Use either isochronous or speed-droop governor operation, as
appropriate.
    (4) With the governor or simulated governor controlling speed using
operator demand, operate the engine at no-load governed speed (at high
speed, not low idle) for at least 15 seconds.
    (5) Record at 1 Hz the mean of feedback speed and torque. Use the
dynamometer to increase torque at a constant rate. Unless the standard-
setting part specifies otherwise, complete the map such that it takes
(2 to 4) min to sweep from no-load governed speed to the lowest speed
below maximum mapped power at which the engine develops (85-95)% of
maximum mapped power. You may map your engine to lower speeds. Stop
recording after you complete the sweep. Use this series of speeds and
torques to generate the power map as described in paragraph (e) of this
section.
    (e) Power mapping. For all engines, create a power-versus-speed map
by transforming torque and speed values to corresponding power values.
Use the mean values from the recorded map data. Do not use any
interpolated values. Multiply each torque by its corresponding speed
and apply the appropriate conversion factors to arrive at units of
power (kW). Interpolate intermediate power values between these power
values, which were calculated from the recorded map data.
    (f) Measured and declared test speeds and torques. You must select
test speeds and torques for cycle generation as required in this
paragraph (f). ``Measured'' values are either directly measured during
the engine mapping process or they are determined from the engine map.
``Declared'' values are specified by the manufacturer. When both
measured and declared values are available, you may use declared test
speeds and torques instead of measured speeds and torques if they meet
the criteria in this paragraph (f). Otherwise,

you must use measured speeds and torques derived from the engine map.
    (1) Measured speeds and torques. Determine the applicable speeds
and torques for the duty cycles you will run:
    (i) Measured maximum test speed for variable-speed engines
according to Sec.  1065.610.
    (ii) Measured maximum test torque for constant-speed engines
according to Sec.  1065.610.
    (iii) Measured ``A'', ``B'', and ``C'' speeds for variable-speed
engines according to Sec.  1065.610.
    (iv) Measured intermediate speed for variable-speed engines
according to Sec.  1065.610.
    (v) For variable-speed engines with a low-speed governor, measure
warm idle speed according to Sec.  1065.510(b) and use this speed for
cycle generation in Sec.  1065.512. For engines with no low-speed
governor, instead use the manufacturer-declared warm idle speed.
    (2) Required declared speeds. You must declare the lowest engine
speed possible with minimum load (i.e., manufacturer-declared warm idle
speed). This is applicable only to variable-speed engines with no low-
speed governor. For engines with no low-speed governor, the declared
warm idle speed is used for cycle generation in Sec.  1065.512. Declare
this speed in a way that is representative of in-use operation. For
example, if your engine is typically connected to an automatic
transmission or a hydrostatic transmission, declare this speed at the
idle speed at which your engine operates when the transmission is
engaged.
    (3) Optional declared speeds. You may use declared speeds instead
of measured speeds as follows:
    (i) You may use a declared value for maximum test speed for
variable-speed engines if it is within (97.5 to 102.5)% of the
corresponding measured value. You may use a higher declared speed if
the length of the ``vector'' at the declared speed is within 2.0% of
the length of the ``vector'' at the measured value. The term vector
refers to the square root of the sum of normalized engine speed squared
and the normalized full-load power (at that speed) squared, consistent
with the calculations in Sec.  1065.610.
    (ii) You may use a declared value for intermediate, ``A'', ``B'',
or ``C'' speeds for steady-state tests if the declared value is within
(97.5 to 102.5)% of the corresponding measured value.
    (4) Required declared torques. If a nonzero idle or minimum torque
is representative of in-use operation, you must declare the appropriate
torque as follows:
    (i) For variable-speed engines, declare a warm idle torque that is
representative of in-use operation. For example, if your engine is
typically connected to an automatic transmission or a hydrostatic
transmission, declare the torque that occurs at the idle speed at which
your engine operates when the transmission is engaged. Use this value
for cycle generation. You may use multiple warm idle torques and
associated idle speeds in cycle generation for representative testing.
For example, for cycles that start the engine and begin with idle, you
may start a cycle in idle with the transmission in neutral with zero
torque and later switch to a different idle with the transmission in
drive with the Curb-Idle Transmission Torque (CITT). For variable-speed
engines intended primarily for propulsion of a vehicle with an
automatic transmission where that engine is subject to a transient duty
cycle with idle operation, you must declare a CITT. You must specify a
CITT based on typical applications at the mean of the range of idle
speeds you specify at stabilized temperature conditions.
    (ii) For constant-speed engines, declare a warm minimum torque that
is representative of in-use operation. For example, if your engine is
typically connected to a machine that does not operate below a certain
minimum torque, declare this torque and use it for cycle generation.
    (5) Optional declared torques. For constant-speed engines you may
declare a maximum test torque. You may use the declared value for cycle
generation if it is within (95 to 100)% of the measured value.
    (g) Other mapping procedures. You may use other mapping procedures
if you believe the procedures specified in this section are unsafe or
unrepresentative for your engine. Any alternate techniques you use must
satisfy the intent of the specified mapping procedures, which is to
determine the maximum available torque at all engine speeds that occur
during a duty cycle. Identify any deviations from this section's
mapping procedures when you submit data to us.

0
99. Section 1065.512 is revised to read as follows:

Sec.  1065.512  Duty cycle generation.

    (a) Generate duty cycles according to this section if the standard-
setting part requires engine mapping to generate a duty cycle for your
engine configuration. The standard-setting part generally defines
applicable duty cycles in a normalized format. A normalized duty cycle
consists of a sequence of paired values for speed and torque or for
speed and power.
    (b) Transform normalized values of speed, torque, and power using
the following conventions:
    (1) Engine speed for variable-speed engines. For variable-speed
engines, normalized speed may be expressed as a percentage between warm
idle speed, fnidle, and maximum test speed,
fntest, or speed may be expressed by referring to a defined
speed by name, such as ``warm idle,'' ``intermediate speed,'' or ``A,''
``B,'' or ``C'' speed. Section 1065.610 describes how to transform
these normalized values into a sequence of reference speeds,
fnref. Running duty cycles with negative or small normalized
speed values near warm idle speed may cause low-speed idle governors to
activate and the engine torque to exceed the reference torque even
though the operator demand is at a minimum. In such cases, we recommend
controlling the dynamometer so it gives priority to follow the
reference torque instead of the reference speed and let the engine
govern the speed. Note that the cycle-validation criteria in Sec.
1065.514 allow an engine to govern itself. This allowance permits you
to test engines with enhanced-idle devices and to simulate the effects
of transmissions such as automatic transmissions. For example, an
enhanced-idle device might be an idle speed value that is normally
commanded only under cold-start conditions to quickly warm up the
engine and aftertreatment devices. In this case, negative and very low
normalized speeds will generate reference speeds below this higher
enhanced idle speed and we recommend controlling the dynamometer so it
gives priority to follow the reference torque, controlling the operator
demand so it gives priority to follow reference speed and let the
engine govern the speed when the operator demand is at minimum.
    (2) Engine torque for variable-speed engines. For variable-speed
engines, normalized torque is expressed as a percentage of the mapped
torque at the corresponding reference speed. Section 1065.610 describes
how to transform normalized torques into a sequence of reference
torques, Tref. Section 1065.610 also describes special
requirements for modifying transient duty cycles for variable-speed
engines intended primarily for propulsion of a vehicle with an
automatic transmission. Section 1065.610 also describes under what
conditions you may command Tref greater than the reference
torque you calculated from a normalized duty cycle. This provision
permits you to

command Tref values that are limited by a declared minimum
torque. For any negative torque commands, command minimum operator
demand and use the dynamometer to control engine speed to the reference
speed, but if reference speed is so low that the idle governor
activates, we recommend using the dynamometer to control torque to
zero, CITT, or a declared minimum torque as appropriate. Note that you
may omit power and torque points during motoring from the cycle-
validation criteria in Sec.  1065.514. Also, use the maximum mapped
torque at the minimum mapped speed as the maximum torque for any
reference speed at or below the minimum mapped speed.
    (3) Engine torque for constant-speed engines. For constant-speed
engines, normalized torque is expressed as a percentage of maximum test
torque, Ttest. Section 1065.610 describes how to transform
normalized torques into a sequence of reference torques,
Tref. Section 1065.610 also describes under what conditions
you may command Tref greater than the reference torque you
calculated from the normalized duty cycle. This provision permits you
to command Tref values that are limited by a declared
minimum torque.
    (4) Engine power. For all engines, normalized power is expressed as
a percentage of mapped power at maximum test speed, fntest,
unless otherwise specified by the standard-setting part. Section
1065.610 describes how to transform these normalized values into a
sequence of reference powers, Pref. Convert these reference
powers to corresponding torques for operator demand and dynamometer
control. Use the reference speed associated with each reference power
point for this conversion. As with cycles specified with % torque,
issue torque commands more frequently and linearly interpolate between
these reference torque values generated from cycles with % power.
    (5) Ramped-modal cycles. For ramped modal cycles, generate
reference speed and torque values at 1 Hz and use this sequence of
points to run the cycle and validate it in the same manner as with a
transient cycle. During the transition between modes, linearly ramp the
denormalized reference speed and torque values between modes to
generate reference points at 1 Hz. Do not linearly ramp the normalized
reference torque values between modes and then denormalize them. Do not
linearly ramp normalized or denormalized reference power points. These
cases will produce nonlinear torque ramps in the denormalized reference
torques. If the speed and torque ramp runs through a point above the
engine's torque curve, continue to command the reference torques and
allow the operator demand to go to maximum. Note that you may omit
power and either torque or speed points from the cycle-validation
criteria under these conditions as specified in Sec.  1065.514.
    (c) For variable-speed engines, command reference speeds and
torques sequentially to perform a duty cycle. Issue speed and torque
commands at a frequency of at least 5 Hz for transient cycles and at
least 1 Hz for steady-state cycles (i.e., discrete-mode and ramped-
modal). Linearly interpolate between the 1 Hz reference values
specified in the standard-setting part to determine more frequently
issued reference speeds and torques. During an emission test, record
the feedback speeds and torques at a frequency of at least 5 Hz for
transient cycles and at least 1 Hz for steady-state cycles. For
transient cycles, you may record the feedback speeds and torques at
lower frequencies (as low as 1 Hz) if you record the average value over
the time interval between recorded values. Calculate the average values
based on feedback values updated at a frequency of at least 5 Hz. Use
these recorded values to calculate cycle-validation statistics and
total work.
    (d) For constant-speed engines, operate the engine with the same
production governor you used to map the engine in Sec.  1065.510 or
simulate the in-use operation of a governor the same way you simulated
it to map the engine in Sec.  1065.510. Command reference torque values
sequentially to perform a duty cycle. Issue torque commands at a
frequency of at least 5 Hz for transient cycles and at least 1 Hz for
steady-state cycles (i.e., discrete-mode, ramped-modal). Linearly
interpolate between the 1 Hz reference values specified in the
standard-setting part to determine more frequently issued reference
torque values. During an emission test, record the feedback speeds and
torques at a frequency of at least 5 Hz for transient cycles and at
least 1 Hz for steady-state cycles. For transient cycles, you may
record the feedback speeds and torques at lower frequencies (as low as
1 Hz) if you record the average value over the time interval between
recorded values. Calculate the average values based on feedback values
updated at a frequency of at least 5 Hz. Use these recorded values to
calculate cycle-validation statistics and total work.
    (e) You may perform practice duty cycles with the test engine to
optimize operator demand and dynamometer controls to meet the cycle-
validation criteria specified in Sec.  1065.514.

0
100. Section 1065.514 is revised to read as follows:

Sec.  1065.514  Cycle-validation criteria for operation over specified
duty cycles.

    Validate the execution of your duty cycle according to this section
unless the standard-setting part specifies otherwise. This section
describes how to determine if the engine's operation during the test
adequately matched the reference duty cycle. This section applies only
to speed, torque, and power from the engine's primary output shaft.
Other work inputs and outputs are not subject to cycle-validation
criteria. You must compare the original reference duty cycle points
generated as described in Sec.  1065.512 to the corresponding feedback
values recorded during the test. You may compare reference duty cycle
points recorded during the test to the corresponding feedback values
recorded during the test as long as the recorded reference values match
the original points generated in Sec.  1065.512. The number of points
in the validation regression are based on the number of points in the
original reference duty cycle generated in Sec.  1065.512. For example
if the original cycle has 1199 reference points at 1 Hz, then the
regression will have up to 1199 pairs of reference and feedback values
at the corresponding moments in the test. The feedback speed and torque
signals may be filtered--either in real-time while the test is run or
afterward in the analysis program. Any filtering that is used on the
feedback signals used for cycle validation must also be used for
calculating work. Feedback signals for control loops may use different
filtering.
    (a) Testing performed by EPA. Our tests must meet the
specifications of paragraph (f) of this section, unless we determine
that failing to meet the specifications is related to engine
performance rather than to shortcomings of the dynamometer or other
laboratory equipment.
    (b) Testing performed by manufacturers. Emission tests that meet
the specifications of paragraph (f) of this section satisfy the
standard-setting part's requirements for duty cycles. You may ask to
use a dynamometer or other laboratory equipment that cannot meet those
specifications. We will approve your request as long as using the
alternate equipment does not adversely affect your ability to show
compliance with the applicable emission standards.
    (c) Time-alignment. Because time lag between feedback values and
the reference values may bias cycle-validation results, you may advance
or delay the entire sequence of feedback engine speed and torque pairs
to

synchronize them with the reference sequence. If you advance or delay
feedback signals for cycle validation, you must make the same
adjustment for calculating work. You may use linear interpolation
between successive recorded feedback signals to time shift an amount
that is a fraction of the recording period.
    (d) Omitting additional points. Besides engine cranking, you may
omit additional points from cycle-validation statistics as described in
the following table:

   Table 1 of Sec.   1065.514.--Permissible Criteria for Omitting Points From Duty-Cycle Regression Statistics
----------------------------------------------------------------------------------------------------------------
  When operator demand is at its . . .         you may omit . . .                       if . . .
----------------------------------------------------------------------------------------------------------------
For reference duty cycles that are specified in terms of speed and torque (fnref, Tref):
----------------------------------------------------------------------------------------------------------------
minimum.................................  power and torque...........  Tref < 0% (motoring).
minimum.................................  power and speed............  fnref = 0% (idle speed) and Tref = 0%
                                                                        (idle torque) and Tref-(2% [middot] Tmax
                                                                        mapped) < T < Tref + (2% [middot]  fnref or T < Tref but not if fn >
                                           speed.                       (fnref [middot] 102%) and T >Tref + (2%
                                                                        [middot] [fnof]nref or < P > Pref but not if
                                           speed.                       fn > (fnref [middot] 102%) and P < Pref
                                                                        + (2% [middot] Pmax mapped).
maximum.................................  power and either torque or   fn < fnref or P < Pref but not if [fnof]n
                                           speed.                       (fnref [middot] 98%) and P < Pref-(2%
                                                                        [middot] Pmax mapped).
----------------------------------------------------------------------------------------------------------------

    (e) Statistical parameters. Use the remaining points to calculate
regression statistics described in Sec.  1065.602. Round calculated
regression statistics to the same number of significant digits as the
criteria to which they are compared. Refer to Table 2 of Sec.  1065.514
for the default criteria and refer to the standard-setting part to
determine if there are other criteria for your engine. Calculate the
following regression statistics:
    (1) Slopes for feedback speed, a1fn, feedback torque,
a1T, and feedback power a1P.
    (2) Intercepts for feedback speed, a0fn, feedback
torque, a0T, and feedback power a0P.
    (3) Standard estimates of error for feedback speed,
SEEfn, feedback torque, SEET, and feedback power
SEEP.
    (4) Coefficients of determination for feedback speed,
r\2\fn, feedback torque, r\2\T, and feedback
power r\2\P.
    (f) Cycle-validation criteria. Unless the standard-setting part
specifies otherwise, use the following criteria to validate a duty
cycle:
    (1) For variable-speed engines, apply all the statistical criteria
in Table 2 of this section.
    (2) For constant-speed engines, apply only the statistical criteria
for torque in Table 2 of this section.
    (3) For discrete-mode steady-state testing, apply cycle-validation
criteria using one of the following approaches:
    (i) Treat the sampling periods from the series of test modes as a
continuous sampling period, analogous to ramped-modal testing and apply
statistical criteria as described in paragraph (f)(1) or (2) of this
section.
    (ii) Evaluate each mode separately to validate the duty cycle. For
variable-speed engines, all speed values measured during the sampling
period for each mode would need to stay within a tolerance of 2 percent
of the reference value, and all load values would need to stay within a
tolerance of 2 percent or  0.27 N[middot]m of the reference
value, whichever is greater. Also, the mean speed value during the
sampling period for each mode would need to be within 1 percent of the
reference value, and the mean load value would need to stay within 1
percent or  0.12 N[middot]m of the reference value,
whichever is greater. The same torque criteria apply for constant-speed
engines but the speed criteria do not apply.

              Table 2 of Sec.   1065.514.--Default Statistical Criteria for Validating Duty Cycles
----------------------------------------------------------------------------------------------------------------
              Parameter                         Speed                    Torque                   Power
----------------------------------------------------------------------------------------------------------------
Slope, a1............................  0.950 <= a1 <= 1.030...  0.830 <= a1 <= 1.030...  0.830 <= a1 <= 1.030.
Absolute value of intercept,           <= 10% of warm idle....  <= 2.0% of maximum       <= 2.0% of maximum
 [verbarlm]a0[verbarlm].                                         mapped torque.           mapped power.
Standard error of estimate, SEE......  <= 5.0% of maximum test  <= 10% of maximum        <= 10% of maximum
                                        speed.                   mapped torque.           mapped power.
Coefficient of determination,r \2\...  >= 0.970...............  >= 0.850...............  >= 0.910.
----------------------------------------------------------------------------------------------------------------

0
101. Section 1065.520 is revised to read as follows:

Sec.  1065.520  Pre-test verification procedures and pre-test data
collection.

    (a) If your engine must comply with a PM standard, follow the
procedures for PM sample preconditioning and tare weighing according to
Sec.  1065.590.
    (b) Unless the standard-setting part specifies different
tolerances, verify that

ambient conditions are within the following tolerances before the test:
    (1) Ambient temperature of (20 to 30) [deg]C.
    (2) Atmospheric pressure of (80.000 to 103.325) kPa and within
 5 kPa of the value recorded at the time of the last engine
map.
    (3) Dilution air conditions as specified in Sec.  1065.140, except
in cases where you preheat your CVS before a cold start test.
    (c) You may test engines at any intake-air humidity, and we may
test engines at any intake-air humidity.
    (d) Verify that auxiliary-work inputs and outputs are configured as
they were during engine mapping, as described inSec.  1065.510(a).
    (e) You may perform a final calibration of the speed, torque, and
proportional-flow control systems, which may include performing
practice duty cycles.
    (f) You may perform the following recommended procedure to
precondition sampling systems:
    (1) Start the engine and use good engineering judgment to bring it
to one of the following:
    (i) 100% torque at any speed above its peak-torque speed.
    (ii) 100% operator demand.
    (2) Operate any dilution systems at their expected flow rates.
Prevent aqueous condensation in the dilution systems.
    (3) Operate any PM sampling systems at their expected flow rates.
    (4) Sample PM for at least 10 min using any sample media. You may
change sample media during preconditioning. You may discard
preconditioning samples without weighing them.
    (5) You may purge any gaseous sampling systems during
preconditioning.
    (6) You may conduct calibrations or verifications on any idle
equipment or analyzers during preconditioning.
    (7) Proceed with the test sequence described in Sec.
1065.530(a)(1).
    (g) Verify the amount of nonmethane contamination in the exhaust
and background HC sampling systems within eight hours of starting each
duty-cycle sequence for laboratory tests. You may verify the
contamination of a background HC sampling system by reading the last
bag fill and purge using zero gas. For any NMHC measurement system that
involves separately measuring methane and subtracting it from a THC
measurement, verify the amount of THC contamination using only the THC
analyzer response. There is no need to operate any separate methane
analyzer for this verification, however you may measure and correct for
THC contamination in the CH4 sample train for the cases
where NMHC is determined by subtracting CH4 from THC, using
an NMC as configured in Sec.  1065.365(d), (e), and (f); and the
calculations in Sec.  1065.660(b)(2). Perform this verification as
follows:
    (1) Select the HC analyzer range for measuring the flow-weighted
mean concentration expected at the HC standard.
    (2) Zero the HC analyzer at the analyzer zero or sample port. Note
that FID zero and span balance gases may be any combination of purified
air or purified nitrogen that meets the specifications of Sec.
1065.750. We recommend FID analyzer zero and span gases that contain
approximately the flow-weighted mean concentration of O2 expected
during testing.
    (3) Span the HC analyzer using span gas introduced at the analyzer
span or sample port. Span on a carbon number basis of one
(C1). For example, if you use a C3H8
span gas of concentration 200 [mu]mol/mol, span the FID to respond with
a value of 600 [mu]mol/mol.
    (4) Overflow zero gas at the HC probe or into a fitting between the
HC probe and its transfer line.
    (5) Measure the THC concentration in the sampling and background
systems as follows:
    (i) For continuous sampling, record the mean THC concentration as
overflow zero air flows.
    (ii) For batch sampling, fill the sample medium (e.g., filter) and
record its mean THC concentration.
    (iii) For the background system, record the mean THC concentration
of the last fill and purge.
    (6) Record this value as the initial THC concentration,
xTHC[THC-FID]init- and use it to correct measured values as
described in Sec.  1065.660.
    (7) If any of the xTHC[THC-FID]init- values exceed the
greatest of the following values, determine the source of the
contamination and take corrective action, such as purging the system
during an additional preconditioning cycle or replacing contaminated
portions:
    (i) 2% of the flow-weighted mean wet, net concentration expected at
the HC (THC or NMHC) standard.
    (ii) 2% of the flow-weighted mean wet, net concentration of HC (THC
or NMHC) measured during testing.
    (iii) 2 [mu]mol/mol.
    (8) If corrective action does not resolve the deficiency, you may
request to use the contaminated system as an alternate procedure under
Sec.  1065.10.

0
102. Section 1065.525 is revised to read as follows:

Sec.  1065.525  Engine starting, restarting, shutdown, and optional
repeating of void discrete modes.

    (a) Start the engine using one of the following methods:
    (1) Start the engine as recommended in the owners manual using a
production starter motor or air-start system and either an adequately
charged battery, a suitable power supply, or a suitable compressed air
source.
    (2) Use the dynamometer to start the engine. To do this, motor the
engine within 25% of its typical in-use cranking speed.
Stop cranking within 1 second of starting the engine.
    (b) If the engine does not start after 15 seconds of cranking, stop
cranking and determine why the engine failed to start, unless the
owners manual or the service-repair manual describes the longer
cranking time as normal.
    (c) Respond to engine stalling with the following steps:
    (1) If the engine stalls during warm-up before emission sampling
begins, restart the engine and continue warm-up.
    (2) If the engine stalls during preconditioning before emission
sampling begins, restart the engine and restart the preconditioning
sequence.
    (3) If the engine stalls at any time after emission sampling begins
for a transient test or ramped-modal cycle test, the test is void.
    (4) Except as described in paragraph (d) of this section, void the
test if the engine stalls at any time after emission sampling begins.
    (d) If emission sampling is interrupted during one of the modes of
a discrete-mode test, you may void the results only for that individual
mode and perform the following steps to continue the test:
    (1) If the engine has stalled, restart the engine.
    (2) Use good engineering judgment to restart the test sequence
using the appropriate steps in Sec.  1065.530(b).
    (3) Precondition the engine by operating at the previous mode for
approximately the same amount of time it operated at that mode for the
last emission measurement.
    (4) Advance to the mode at which the engine stalled and continue
with the duty cycle as specified in the standard-setting part.
    (5) Complete the remainder of the test according to the
requirements in this subpart.
    (e) Shut down the engine according to the manufacturer's
specifications.

0
103. Section 1065.530 is revised to read as follows:

Sec.  1065.530  Emission test sequence.

    (a) Time the start of testing as follows:

    (1) Perform one of the following if you precondition sampling
systems as described in Sec.  1065.520(f):
    (i) For cold-start duty cycles, shut down the engine. Unless the
standard-setting part specifies that you may only perform a natural
engine cooldown, you may perform a forced engine cooldown. Use good
engineering judgment to set up systems to send cooling air across the
engine, to send cool oil through the engine lubrication system, to
remove heat from coolant through the engine cooling system, and to
remove heat from any exhaust aftertreatment systems. In the case of a
forced aftertreatment cooldown, good engineering judgment would
indicate that you not start flowing cooling air until the
aftertreatment system has cooled below its catalytic activation
temperature. For platinum-group metal catalysts, this temperature is
about 200 [deg]C. Once the aftertreatment system has naturally cooled
below its catalytic activation temperature, good engineering judgment
would indicate that you use clean air with a temperature of at least 15
[deg]C, and direct the air through the aftertreatment system in the
normal direction of exhaust flow. Do not use any cooling procedure that
results in unrepresentative emissions (see Sec.  1065.10(c)(1)). You
may start a cold-start duty cycle when the temperatures of an engine's
lubricant, coolant, and aftertreatment systems are all between (20 and
30) [deg]C.
    (ii) For hot-start emission measurements, shut down the engine.
Start the hot-start duty cycle as specified in the standard-setting
part.
    (iii) For testing that involves hot-stabilized emission
measurements, such as any steady-state testing, you may continue to
operate the engine at maximum test speed and 100% torque if that is the
first operating point. Otherwise, operate the engine at warm idle or
the first operating point of the duty cycle. In any case, start the
emission test within 10 min after you complete the preconditioning
procedure.
    (2) If you do not precondition sampling systems, perform one of the
following:
    (i) For cold-start duty cycles, prepare the engine according to
paragraph (a)(1)(i) of this section.
    (ii) For hot-start emission measurements, first operate the engine
at any speed above peak-torque speed and at (65 to 85)% of maximum
mapped power until either the engine coolant, block, or head absolute
temperature is within 2% of its mean value for at least 2
min or until the engine thermostat controls engine temperature. Shut
down the engine. Start the duty cycle within 20 min of engine shutdown.
    (iii) For testing that involves hot-stabilized emission
measurements, bring the engine either to warm idle or the first
operating point of the duty cycle. Start the test within 10 min of
achieving temperature stability. Determine temperature stability either
as the point at which the engine coolant, block, or head absolute
temperature is within 2% of its mean value for at least 2
min, or as the point at which the engine thermostat controls engine
temperature.
    (b) Take the following steps before emission sampling begins:
    (1) For batch sampling, connect clean storage media, such as
evacuated bags or tare-weighed filters.
    (2) Start all measurement instruments according to the instrument
manufacturer's instructions and using good engineering judgment.
    (3) Start dilution systems, sample pumps, cooling fans, and the
data-collection system.
    (4) Pre-heat or pre-cool heat exchangers in the sampling system to
within their operating temperature tolerances for a test.
    (5) Allow heated or cooled components such as sample lines,
filters, chillers, and pumps to stabilize at their operating
temperatures.
    (6) Verify that there are no significant vacuum-side leaks
according to Sec.  1065.345.
    (7) Adjust the sample flow rates to desired levels, using bypass
flow, if desired.
    (8) Zero or re-zero any electronic integrating devices, before the
start of any test interval.
    (9) Select gas analyzer ranges. You may automatically or manually
switch gas analyzer ranges during a test only if switching is performed
by changing the span over which the digital resolution of the
instrument is applied. During a test you may not switch the gains of an
analyzer's analog operational amplifier(s).
    (10) Zero and span all continuous analyzers using NIST-traceable
gases that meet the specifications of Sec.  1065.750. Span FID
analyzers on a carbon number basis of one (1), C1. For
example, if you use a C3H8 span gas of
concentration 200 [mu]mol/mol, span the FID to respond with a value of
600 [mu]mol/mol. Span FID analyzers consistent with the determination
of their respective response factors, RF, and penetration fractions,
PF, according to Sec.  1065.365.
    (11) We recommend that you verify gas analyzer responses after
zeroing and spanning by sampling a calibration gas that has a
concentration near one-half of the span gas concentration. Based on the
results and good engineering judgment, you may decide whether or not to
re-zero, re-span, or re-calibrate a gas analyzer before starting a
test.
    (12) If you correct for dilution air background concentrations of
engine exhaust constituents, start measuring and recording background
concentrations.
    (13) Drain any condensate from the intake air system and close any
intake air condensate drains that are not normally open during in-use
operation.
    (c) Start testing as follows:
    (1) If an engine is already running and warmed up, and starting is
not part of the duty cycle, perform the following for the various duty
cycles:
    (i) Transient and steady-state ramped-modal cycles. Simultaneously
start running the duty cycle, sampling exhaust gases, recording data,
and integrating measured values.
    (ii) Steady-state discrete-mode cycles. Control the engine
operation to match the first mode in the test cycle. This will require
controlling engine speed and load, engine load, or other operator
demand settings, as specified in the standard-setting part. Follow the
instructions in the standard-setting part to determine how long to
stabilize engine operation at each mode, how long to sample emissions
at each mode, and how to transition between modes.
    (2) If engine starting is part of the duty cycle, initiate data
logging, sampling of exhaust gases, and integrating measured values
before attempting to start the engine. Initiate the duty cycle when the
engine starts.
    (d) At the end of each test interval, continue to operate all
sampling and dilution systems to allow the sampling system's response
time to elapse. Then stop all sampling and recording, including the
recording of background samples. Finally, stop any integrating devices
and indicate the end of the duty cycle in the recorded data.
    (e) Shut down the engine if you have completed testing or if it is
part of the duty cycle.
    (f) If testing involves another duty cycle after a soak period with
the engine off, start a timer when the engine shuts down, and repeat
the steps in paragraphs (b) through (e) of this section as needed.
    (g) Take the following steps after emission sampling is complete:
    (1) For any proportional batch sample, such as a bag sample or PM
sample, verify that proportional sampling was maintained according to
Sec.  1065.545. Void any samples that did not maintain proportional
sampling according to Sec.  1065.545.

    (2) Place any used PM samples into covered or sealed containers and
return them to the PM-stabilization environment. Follow the PM sample
post-conditioning and total weighing procedures in Sec.  1065.595.
    (3) As soon as practical after the duty cycle is complete, or
during the soak period if practical, perform the following:
    (i) Zero and span all batch gas analyzers no later than 30 minutes
after the duty cycle is complete, or during the soak period if
practical.
    (ii) Analyze any conventional gaseous batch samples no later than
30 minutes after the duty cycle is complete, or during the soak period
if practical.
    (iii) Analyze background samples no later than 60 minutes after the
duty cycle is complete.
    (iv) Analyze non-conventional gaseous batch samples, such as
ethanol (NMCHE) as soon as practical using good engineering judgment.
    (4) After quantifying exhaust gases, verify drift as follows:
    (i) For batch and continuous gas anlyzers, record the mean analyzer
value after stabilizing a zero gas to the analyzer. Stabilization may
include time to purge the analyzer of any sample gas, plus any
additional time to account for analyzer response.
    (ii) Record the mean analyzer value after stabilizing the span gas
to the analyzer. Stabilization may include time to purge the analyzer
of any sample gas, plus any additional time to account for analyzer
response.
    (iii) Use these data to validate and correct for drift as described
in Sec.  1065.550.
    (h) Unless the standard-setting part specifies otherwise, determine
whether or not the test meets the cycle-validation criteria in Sec.
1065.514.
    (1) If the criteria void the test, you may retest using the same
denormalized duty cycle, or you may re-map the engine, denormalize the
reference duty cycle based on the new map and retest the engine using
the new denormalized duty cycle.
    (2) If the criteria void the test for a constant-speed engine only
during commands of maximum test torque, you may do the following:
    (i) Determine the first and last feedback speeds at which maximum
test torque was commanded.
    (ii) If the last speed is greater than or equal to 90% of the first
speed, the test is void. You may retest using the same denormalized
duty cycle, or you may re-map the engine, denormalize the reference
duty cycle based on the new map and retest the engine using the new
denormalized duty cycle.
    (iii) If the last speed is less than 90% of the first speed, reduce
maximum test torque by 5%, and proceed as follows:
    (A) Denormalize the entire duty cycle based on the reduced maximum
test torque according to Sec.  1065.512.
    (B) Retest the engine using the denormalized test cycle that is
based on the reduced maximum test torque.
    (C) If your engine still fails the cycle criteria, reduce the
maximum test torque by another 5% of the original maximum test torque.
    (D) If your engine fails after repeating this procedure four times,
such that your engine still fails after you have reduced the maximum
test torque by 20% of the original maximum test torque, notify us and
we will consider specifying a more appropriate duty cycle for your
engine under the provisions of Sec.  1065.10(c).
    (i) [Reserved]
    (j) Measure and record ambient temperature, pressure, and humidity,
as appropriate.

0
104. Section 1065.545 is revised to read as follows:

Sec.  1065.545  Validation of proportional flow control for batch
sampling and minimum dilution ratio for PM batch sampling.

    For any proportional batch sample such as a bag or PM filter,
demonstrate that proportional sampling was maintained using one of the
following, noting that you may omit up to 5% of the total number of
data points as outliers:
    (a) For any pair of flow meters, use recorded sample and total flow
rates, where total flow rate means the raw exhaust flow rate for raw
exhaust sampling and the dilute exhaust flow rate for CVS sampling, or
their 1 Hz means with the statistical calculations in Sec.  1065.602.
Determine the standard error of the estimate, SEE, of the sample flow
rate versus the total flow rate. For each test interval, demonstrate
that SEE was less than or equal to 3.5% of the mean sample flow rate.
    (b) For any pair of flow meters, use recorded sample and total flow
rates, where total flow rate means the raw exhaust flow rate for raw
exhaust sampling and the dilute exhaust flow rate for CVS sampling, or
their 1 Hz means to demonstrate that each flow rate was constant within
2.5% of its respective mean or target flow rate. You may
use the following options instead of recording the respective flow rate
of each type of meter:
    (1) Critical-flow venturi option. For critical-flow venturis, you
may use recorded venturi-inlet conditions or their 1 Hz means.
Demonstrate that the flow density at the venturi inlet was constant
within 2.5% of the mean or target density over each test
interval. For a CVS critical-flow venturi, you may demonstrate this by
showing that the absolute temperature at the venturi inlet was constant
within 4% of the mean or target absolute temperature over
each test interval.
    (2) Positive-displacement pump option. You may use recorded pump-
inlet conditions or their 1 Hz means. Demonstrate that the flow density
at the pump inlet was constant within 2.5% of the mean or
target density over each test interval. For a CVS pump, you may
demonstrate this by showing that the absolute temperature at the pump
inlet was constant within 2% of the mean or target absolute
temperature over each test interval.
    (c) Using good engineering judgment, demonstrate with an
engineering analysis that the proportional-flow control system
inherently ensures proportional sampling under all circumstances
expected during testing. For example, you might use CFVs for both
sample flow and total flow and demonstrate that they always have the
same inlet pressures and temperatures and that they always operate
under critical-flow conditions.
    (d) Use measured or calculated flows and/or tracer gas
concentrations (e.g., CO2) to determine the minimum dilution ratio for
PM batch sampling over the test interval.

0
105. Section 1065.550 is revised to read as follows:

Sec.  1065.550  Gas analyzer range validation, drift validation, and
drift correction.

    (a) Range validation. If an analyzer operated above 100% of its
range at any time during the test, perform the following steps:
    (1) For batch sampling, re-analyze the sample using the lowest
analyzer range that results in a maximum instrument response below
100%. Report the result from the lowest range from which the analyzer
operates below 100% of its range.
    (2) For continuous sampling, repeat the entire test using the next
higher analyzer range. If the analyzer again operates above 100% of its
range, repeat the test using the next higher range. Continue to repeat
the test until the analyzer always operates at less than 100% of its
range.
    (b) Drift validation and drift correction. Calculate two sets of
brake-specific emission results. Calculate one set using the data
before drift correction and calculate the other set after correcting
all the data for drift according to Sec.  1065.672. Use the two sets of
brake-specific emission results as follows:

    (1) This test is validated for drift if, for each regulated
pollutant, the difference between the uncorrected and the corrected
brake-specific emission values is within 4% of the
uncorrected results or applicable standard, whichever is greater. If
not, the entire test is void.
    (2) If the test is validated for drift, you must use only the
drift-corrected emission results when reporting emissions, unless you
demonstrate to us that using the drift-corrected results adversely
affects your ability to demonstrate that your engine complies with the
applicable standards.

0
106. Section 1065.590 is revised to read as follows:

Sec.  1065.590  PM sampling media (e.g., filters) preconditioning and
tare weighing.

    Before an emission test, take the following steps to prepare PM
sampling media (e.g., filters) and equipment for PM measurements:
    (a) Make sure the balance and PM-stabilization environments meet
the periodic verifications in Sec.  1065.390.
    (b) Visually inspect unused sample media (e.g., filters) for
defects and discard defective media.
    (c) To handle PM sampling media (e.g., filters), use electrically
grounded tweezers or a grounding strap, as described in Sec.  1065.190.
    (d) Place unused sample media (e.g., filters) in one or more
containers that are open to the PM-stabilization environment. If you
are using filters, you may place them in the bottom half of a filter
cassette.
    (e) Stabilize sample media (e.g., filters) in the PM-stabilization
environment. Consider an unused sample medium stabilized as long as it
has been in the PM-stabilization environment for a minimum of 30 min,
during which the PM-stabilization environment has been within the
specifications of Sec.  1065.190.
    (f) Weigh the sample media (e.g., filters) automatically or
manually, as follows:
    (1) For automatic weighing, follow the automation system
manufacturer's instructions to prepare samples for weighing. This may
include placing the samples in a special container.
    (2) For manual weighing, use good engineering judgment to determine
if substitution weighing is necessary to show that an engine meets the
applicable standard. You may follow the substitution weighing procedure
in paragraph (j) of this section, or you may develop your own
procedure.
    (g) Correct the measured mass of each sample medium (e.g., filter)
for buoyancy as described in Sec.  1065.690. These buoyancy-corrected
values are subsequently subtracted from the post-test mass of the
corresponding sample media (e.g., filters) and collected PM to
determine the mass of PM emitted during the test.
    (h) You may repeat measurements to determine the mean mass of each
sample medium (e.g., filter). Use good engineering judgment to exclude
outliers from the calculation of mean mass values.
    (i) If you use filters as sample media, load unused filters that
have been tare-weighed into clean filter cassettes and place the loaded
cassettes in a clean, covered or sealed container before removing them
from the stabilization environment for transport to the test site for
sampling. We recommend that you keep filter cassettes clean by
periodically washing or wiping them with a compatible solvent applied
using a lint-free cloth. Depending upon your cassette material, ethanol
(C2H5OH) might be an acceptable solvent. Your cleaning frequency will
depend on your engine's level of PM and HC emissions.
    (j) Substitution weighing involves measurement of a reference
weight before and after each weighing of PM sampling media (e.g.,
filters). While substitution weighing requires more measurements, it
corrects for a balance's zero-drift and it relies on balance linearity
only over a small range. This is most advantageous when quantifying net
PM masses that are less than 0.1% of the sample medium's mass. However,
it may not be advantageous when net PM masses exceed 1% of the sample
medium's mass. If you utilize substitution weighing, it must be used
for both pre-test and post-test weighing. The same substitution weight
must be used for both pre-test and post-test weighing. Correct the mass
of the substitution weight for buoyancy if the density of the
substitution weight is less than 2.0 g/cm3. The following
steps are an example of substitution weighing:
    (1) Use electrically grounded tweezers or a grounding strap, as
described in Sec.  1065.190.
    (2) Use a static neutralizer as described in Sec.  1065.190 to
minimize static electric charge on any object before it is placed on
the balance pan.
    (3) Select a substitution weight that meets the requirements for
calibration weights found in Sec.  1065.790. The substitution weight
must also have the same density as the weight you use to span the
microbalance, and be similar in mass to an unused sample medium (e.g.,
filter). A 47 mm PTFE membrane filter will typically have a mass in the
range of 80 to 100 mg.
    (4) Record the stable balance reading, then remove the calibration
weight.
    (5) Weigh an unused sample medium (e.g., a new filter), record the
stable balance reading and record the balance environment's dewpoint,
ambient temperature, and atmospheric pressure.
    (6) Reweigh the calibration weight and record the stable balance
reading.
    (7) Calculate the arithmetic mean of the two calibration-weight
readings that you recorded immediately before and after weighing the
unused sample. Subtract that mean value from the unused sample reading,
then add the true mass of the calibration weight as stated on the
calibration-weight certificate. Record this result. This is the unused
sample's tare weight without correcting for buoyancy.
    (8) Repeat these substitution-weighing steps for the remainder of
your unused sample media.
    (9) Once weighing is completed, follow the instructions given in
paragraphs (g) through (i) of this section.

0
107. Section 1065.595 is revised to read as follows:

Sec.  1065.595  PM sample post-conditioning and total weighing.

    After testing is complete, return the sample media (e.g., filters)
to the weighing and PM-stabilization environments.
    (a) Make sure the weighing and PM-stabilization environments meet
the ambient condition specifications in Sec.  1065.190(e)(1). If those
specifications are not met, leave the test sample media (e.g., filters)
covered until proper conditions have been met.
    (b) In the PM-stabilization environment, remove PM samples from
sealed containers. If you use filters, you may remove them from their
cassettes before or after stabilization. We recommend always removing
the top portion of the cassette before stabilization. When you remove a
filter from a cassette, separate the top half of the cassette from the
bottom half using a cassette separator designed for this purpose.
    (c) To handle PM samples, use electrically grounded tweezers or a
grounding strap, as described in Sec.  1065.190.
    (d) Visually inspect the sampling media (e.g., filters) and
collected particulate. If either the sample media (e.g., filters) or
particulate sample appear to have been compromised, or the particulate
matter contacts any surface other than the filter, the sample may not
be used to determine particulate emissions. In the case of contact with
another surface, clean the affected surface before continuing.
    (e) To stabilize PM samples, place them in one or more containers
that are

open to the PM-stabilization environment, as described in Sec.
1065.190. If you expect that a sample medium's (e.g., filter's) total
surface concentration of PM will be less than 400 [mu]g, assuming a 38
mm diameter filter stain area, expose the filter to a PM-stabilization
environment meeting the specifications of Sec.  1065.190 for at least
30 minutes before weighing. If you expect a higher PM concentration or
do not know what PM concentration to expect, expose the filter to the
stabilization environment for at least 60 minutes before weighing. Note
that 400 [mu]g on sample media (e.g., filters) is an approximate net
mass of 0.07 g/kW[middot]hr for a hot-start test with compression-
ignition engines tested according to 40 CFR part 86, subpart N, or 50
mg/mile for light-duty vehicles tested according to 40 CFR part 86,
subpart B.
    (f) Repeat the procedures in Sec.  1065.590(f) through (i) to
determine post-test mass of the sample media (e.g., filters).
    (g) Subtract each buoyancy-corrected tare mass of the sample medium
(e.g., filter) from its respective buoyancy-corrected mass. The result
is the net PM mass, mPM. Use mPM in emission
calculations in Sec.  1065.650.

Subpart G--[Amended]

0
108. Section 1065.601 is amended by revising paragraph (c)(1) to read
as follows:

Sec.  1065.601  Overview.

* * * * *
    (c) * * *
    (1) Mass-based emission calculations prescribed by the
International Organization for Standardization (ISO), according to ISO
8178, except the following:
    (i) ISO 8178-1 Section 14.4, NOX Correction for Humidity
and Temperature. See Sec.  1065.670 for approved methods for humidity
corrections.
    (ii) ISO 8178-1 Section 15.1, Particulate Correction Factor for
Humidity.
* * * * *
0
109. Section 1065.602 is amended by revising paragraphs (f)(3) before
the table and (l) introductory text to read as follows:

Sec.  1065.602  Statistics.

* * * * *
    (f) * * *
    (3) Use Table 1 of this section to compare t to the
tcrit values tabulated versus the number of degrees of
freedom. If t is less than tcrit, then t passes the t-test.
The Microsoft Excel software package contains a TINV function that
returns results equivalent to Sec.  1065.602 Table 1 and may be used in
place of Table 1.
* * * * *
    (l) Flow-weighted mean concentration. In some sections of this
part, you may need to calculate a flow-weighted mean concentration to
determine the applicability of certain provisions. A flow-weighted mean
is the mean of a quantity after it is weighted proportional to a
corresponding flow rate. For example, if a gas concentration is
measured continuously from the raw exhaust of an engine, its flow-
weighted mean concentration is the sum of the products of each recorded
concentration times its respective exhaust molar flow rate, divided by
the sum of the recorded flow rate values. As another example, the bag
concentration from a CVS system is the same as the flow-weighted mean
concentration because the CVS system itself flow-weights the bag
concentration. You might already expect a certain flow-weighted mean
concentration of an emission at its standard based on previous testing
with similar engines or testing with similar equipment and instruments.
If you need to estimate your expected flow-weighted mean concentration
of an emission at its standard, we recommend using the following
examples as a guide for how to estimate the flow-weighted mean
concentration expected at the standard. Note that these examples are
not exact and that they contain assumptions that are not always valid.
Use good engineering judgment to determine if you can use similar
assumptions.
* * * * *

0
110. Section 1065.610 is revised to read as follows:

Sec.  1065.610  Duty cycle generation.

    This section describes how to generate duty cycles that are
specific to your engine, based on the normalized duty cycles in the
standard-setting part. During an emission test, use a duty cycle that
is specific to your engine to command engine speed, torque, and power,
as applicable, using an engine dynamometer and an engine operator
demand. Paragraph (a) of this section describes how to ``normalize''
your engine's map to determine the maximum test speed and torque for
your engine. The rest of this section describes how to use these values
to ``denormalize'' the duty cycles in the standard-setting parts, which
are all published on a normalized basis. Thus, the term ``normalized''
in paragraph (a) of this section refers to different values than it
does in the rest of the section.
    (a) Maximum test speed, fntest. This section generally
applies to duty cycles for variable-speed engines. For constant-speed
engines subject to duty cycles that specify normalized speed commands,
use the no-load governed speed as the measured fntest. This
is the highest engine speed where an engine outputs zero torque. For
variable-speed engines, determine the measured fntest from
the power-versus-speed map, generated according to Sec.  1065.510, as
follows:
    (1) Based on the map, determine maximum power, Pmax, and
the speed at which maximum power occurred, fnPmax. Divide
every recorded power by Pmax and divide every recorded speed
by fnPmax. The result is a normalized power-versus-speed
map. Your measured fntest is the speed at which the sum of
the squares of normalized speed and power is maximum, as follows:

fntest = fni at the maximum of
(fnnormi\2\ + Pnormi\2\)

Eq. 1065.610-1

Where:

fntest = maximum test speed.
i = an indexing variable that represents one recorded value of an
engine map.
fnnormi = an engine speed normalized by dividing it by
fnPmax.
Pnormi = an engine power normalized by dividing it by
Pmax.

Example:

(fnnorm1 = 1.002, Pnorm1 = 0.978,
fn1 = 2359.71)
(fnnorm2 = 1.004, Pnorm2 = 0.977,
fn2 = 2364.42)
(fnnorm3 = 1.006, Pnorm3 = 0.974,
fn3 = 2369.13)
(fnnorm12 + Pnorm1\2\) = (1.002\2\
+ 0.978\2\) = 1.960
(fnnorm2\2\ + Pnorm2\2\) = (1.004\2\ +
0.977\2\) = 1.963
(fnnorm3\2\ + Pnorm3\2\) = (1.006\2\ +
0.974\2\) = 1.961
maximum = 1.963 at i = 2
fntest = 2364.42 rev/min

    (2) For variable-speed engines, transform normalized speeds to
reference speeds according to paragraph (c) of this section by using
the measured maximum test speed determined according to paragraph
(a)(1) of this section--or use your declared maximum test speed, as
allowed in Sec.  1065.510.
    (3) For constant-speed engines, transform normalized speeds to
reference speeds according to paragraph (c) of this section by using
the measured no-load governed speed--or use your declared maximum test
speed, as allowed in Sec.  1065.510.
    (b) Maximum test torque, Ttest. For constant-speed engines,
determine the measured Ttest from the power-versus-speed
map, generated according to Sec.  1065.510, as follows:
    (1) Based on the map, determine maximum power, Pmax, and
the speed at which maximum power occurs, fnPmax. Divide
every recorded power by Pmax and divide every recorded speed
by fnPmax. The result is a normalized power-

versus-speed map. Your measured Ttest is the torque at which
the sum of the squares of normalized speed and power is maximum, as
follows:

Ttest = Ti at the maximum of
(fnnormi\2\ + Pnormi\2\)

Eq. 1065.610-2

Where:

Ttest = maximum test torque.

Example:
(fnnorm1 = 1.002, Pnorm1 = 0.978, T\1\ =
722.62 Nxm)
(fnnorm2 = 1.004, Pnorm2 = 0.977, T\2\ =
720.44 Nxm)
(fnnorm3 = 1.006, Pnorm3 = 0.974,
T3 = 716.80 Nxm)
(fnnorm1\2\ + Pnorm1\2\) = (1.002\2\ +
0.978\2\) = 1.960
(fnnorm1\2\ + Pnorm1\2\) = (1.004\2\ +
0.977\2\) = 1.963
(fnnorm1\2\ + Pnorm1\2\) = (1.006\2\ +
0.974\2\) = 1.961
maximum = 1.963 at i = 2
Ttest = 720.44 Nxm

    (2) Transform normalized torques to reference torques according to
paragraph (d) of this section by using the measured maximum test torque
determined according to paragraph (b)(1) of this section--or use your
declared maximum test torque, as allowed in Sec.  1065.510.
    (c) Generating reference speed values from normalized duty cycle
speeds. Transform normalized speed values to reference values as
follows:
    (1) % speed. If your normalized duty cycle specifies % speed
values, use your warm idle speed and your maximum test speed to
transform the duty cycle, as follows:

fnref = % speed [middot] (fntest -
fnidle) + fnidle

Eq. 1065.610-3

Example:

% speed = 85%
fntest = 2364 rev/min
fnidle = 650 rev/min
fnref = 85% [middot] (2364-650 ) + 650
fnref = 2107 rev/min

    (2) A, B, and C speeds. If your normalized duty cycle specifies
speeds as A, B, or C values, use your power-versus-speed curve to
determine the lowest speed below maximum power at which 50% of maximum
power occurs. Denote this value as nlo. Take nlo
to be warm idle speed if all power points at speeds below the maximum
power speed are higher than 50% of maximum power. Also determine the
highest speed above maximum power at which 70% of maximum power occurs.
Denote this value as nhi. If all power points at speeds
above the maximum power speed are higher than 70% of maximum power,
take nhi to be the declared maximum safe engine speed or the
declared maximum representative engine speed, whichever is lower. Use
nhi and nlo to calculate reference values for A,
B, or C speeds as follows:
fnrefA = 0.25 [middot] (nhi-nlo) +
nlo

Eq. 1065.610-4

fnrefB = 0.50 [middot] (nhi - nlo) +
nlo

Eq. 1065.610-5
fnrefC = 0.75 [middot] (nhi - nlo) +
nlo
Eq. 1065.610-6

Example:

nlo = 1005 rev/min
nhi = 2385 rev/min
fnrefA = 0.25 [middot] (2385-1005) + 1005
fnrefB = 0.50 [middot] (2385-1005) + 1005
fnrefC = 0.75 [middot] (2385-1005) + 1005
fnrefA = 1350 rev/min
fnrefB = 1695 rev/min
fnrefC = 2040 rev/min

    (3) Intermediate speed. If your normalized duty cycle specifies a
speed as ``intermediate speed,'' use your torque-versus-speed curve to
determine the speed at which maximum torque occurs. This is peak torque
speed. Identify your reference intermediate speed as one of the
following values:
    (i) Peak torque speed if it is between (60 and 75)% of maximum test
speed.
    (ii) 60% of maximum test speed if peak torque speed is less than
60% of maximum test speed.
    (iii) 75% of maximum test speed if peak torque speed is greater
than 75% of maximum test speed.
    (d) Generating reference torques from normalized duty-cycle
torques. Transform normalized torques to reference torques using your
map of maximum torque versus speed.
    (1) Reference torque for variable-speed engines. For a given speed
point, multiply the corresponding % torque by the maximum torque at
that speed, according to your map. If your engine is subject to a
reference duty cycle that specifies negative torque values (i.e.,
engine motoring), use negative torque for those motoring points (i.e.,
the motoring torque). If you map negative torque as allowed under Sec.
1065.510 (c)(2) and the low-speed governor activates, resulting in
positive torques, you may replace those positive motoring mapped
torques with negative values between zero and the largest negative
motoring torque. For both maximum and motoring torque maps, linearly
interpolate mapped torque values to determine torque between mapped
speeds. If the reference speed is below the minimum mapped speed (i.e.,
95% of idle speed or 95% of lowest required speed, whichever is
higher), use the mapped torque at the minimum mapped speed as the
reference torque. The result is the reference torque for each speed
point.
    (2) Reference torque for constant-speed engines. Multiply a %
torque value by your maximum test torque. The result is the reference
torque for each point.
    (3) Required deviations. We require the following deviations for
variable-speed engines intended primarily for propulsion of a vehicle
with an automatic transmission where that engine is subject to a
transient duty cycle with idle operation. These deviations are intended
to produce a more representative transient duty cycle for these
applications. For steady-state duty cycles or transient duty cycles
with no idle operation, these requirements do not apply. Idle points
for steady state duty cycles of such engines are to be run at
conditions simulating neutral or park on the transmission.
    (i) Zero-percent speed is the warm idle speed measured according to
Sec.  1065.510(b)(6) with CITT applied, i.e., measured warm idle speed
in drive.
    (ii) If the cycle begins with a set of contiguous idle points
(zero-percent speed, and zero-percent torque), leave the reference
torques set to zero for this initial contiguous idle segment. This is
to represent free idle operation with the transmission in neutral or
park at the start of the transient duty cycle, after the engine is
started. If the initial idle segment is longer than 24 s, change the
reference torques for the remaining idle points in the initial
contiguous idle segment to CITT (i.e., change idle points corresponding
to 25 s to the end of the initial idle segment to CITT). This is to
represent shifting the transmission to drive.
    (iii) For all other idle points, change the reference torque to
CITT. This is to represent the transmission operating in drive.
    (iv) If the engine is intended primarily for automatic
transmissions with a Neutral-When-Stationary feature that automatically
shifts the transmission to neutral after the vehicle is stopped for a
designated time and automatically shifts back to drive when the
operator increases demand (i.e., pushes the accelerator pedal), change
the reference torque back to zero for idle points in drive after the
designated time.
    (v) For all points with normalized speed at or below zero percent
and reference torque from zero to CITT, set the reference torque to
CITT. This is to provide smoother torque references below idle speed.
    (vi) For motoring points, make no changes.
    (vii) For consecutive points with reference torques from zero to
CITT that immediately follow idle points, change their reference
torques to CITT. This is to provide smooth torque transition out of
idle operation. This does not apply if the Neutral-When-Stationary
feature is used and the transmission has shifted to neutral.

    (viii) For consecutive points with reference torque from zero to
CITT that immediately precede idle points, change their reference
torques to CITT. This is to provide smooth torque transition into idle
operation.
    (4) Permissible deviations for any engine. If your engine does not
operate below a certain minimum torque under normal in-use conditions,
you may use a declared minimum torque as the reference value instead of
any value denormalized to be less than the declared value. For example,
if your engine is connected to a hydrostatic transmission and it has a
minimum torque even when all the driven hydraulic actuators and motors
are stationary and the engine is at idle, then you may use this
declared minimum torque as a reference torque value instead of any
reference torque value generated under paragraph (d)(1) or (2) of this
section that is between zero and this declared minimum torque.
    (e) Generating reference power values from normalized duty cycle
powers. Transform normalized power values to reference speed and power
values using your map of maximum power versus speed.
    (1) First transform normalized speed values into reference speed
values. For a given speed point, multiply the corresponding % power by
the mapped power at maximum test speed, fntest, unless
specified otherwise by the standard-setting part. The result is the
reference power for each speed point, Pref. Convert these
reference powers to corresponding torques for operator demand and
dynamometer control and for duty cycle validation per 1065.514. Use the
reference speed associated with each reference power point for this
conversion. As with cycles specified with % torque, linearly
interpolate between these reference torque values generated from cycles
with % power.
    (2) Permissible deviations for any engine. If your engine does not
operate below a certain power under normal in-use conditions, you may
use a declared minimum power as the reference value instead of any
value denormalized to be less than the declared value. For example, if
your engine is directly connected to a propeller, it may have a minimum
power called idle power. In this case, you may use this declared
minimum power as a reference power value instead of any reference power
value generated per paragraph (e)(1) of this section that is from zero
to this declared minimum power.
0
111. Section 1065.640 is amended by revising paragraphs (a) and (e) and
redesignating the second ``Table 3'' as ``Table 4'' to read as follows:

Sec.  1065.640  Flow meter calibration calculations.

* * * * *
    (a) Reference meter conversions. The calibration equations in this
section use molar flow rate, nref, as a reference quantity.
If your reference meter outputs a flow rate in a different quantity,
such as standard volume rate, Vstdref, actual volume rate,
Vactref, or mass rate, mref, convert your
reference meter output to a molar flow rate using the following
equations, noting that while values for volume rate, mass rate,
pressure, temperature, and molar mass may change during an emission
test, you should ensure that they are as constant as practical for each
individual set point during a flow meter calibration:
[GRAPHIC] [TIFF OMITTED] TR06MY08.022

Where:
Nref = reference molar flow rate.
Vstdref = reference volume flow rate, corrected to a
standard pressure and a standard temperature.
Vactref = reference volume flow rate at the actual
pressure and temperature of the flow rate.
Nref = reference mass flow.
Pstd = standard pressure.
Pact = actual pressure of the flow rate.
Tstd = standard temperature.
Tact = actual temperature of the flow rate.
R = molar gas constant.
Mmix = molar mass of the flow rate.

Example 1:

Vstdref = 1000.00 ft3/min = 0.471948
m3/s
P = 29.9213 in Hg @ 32 [deg]F = 101325 Pa
T = 68.0 [deg]F = 293.15 K
R = 8.314472 J/(mol [middot] K)
[GRAPHIC] [TIFF OMITTED] TR06MY08.023

Nref = 19.169 mol/s

Example 2:

Mref = 17.2683 kg/min = 287.805 g/s
Mmix = 28.7805 g/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.024

    nref = 10.0000 mol/s

    (e) CFV calibration. Some CFV flow meters consist of a single
venturi and some consist of multiple venturis, where different
combinations of venturis are used to meter different flow rates. For
CFV flow meters that consist of multiple venturis, either calibrate
each venturi independently to determine a separate discharge
coefficient, Cd, for each venturi, or calibrate each combination of
venturis as one venturi. In the case where you calibrate a combination
of venturis, use the sum of the active venturi throat areas as At, the
square root of the sum of the squares of the active venturi throat
diameters as dt, and the ratio of the venturi throat to inlet diameters
as the ratio of the square root of the sum of the active venturi throat
diameters (dt) to the diameter of the common entrance to all of the
venturis (D). To determine the Cd for a single venturi or a single
combination of venturis, perform the following steps:
    (1) Use the data collected at each calibration set point to
calculate an individual Cd for each point using Eq. 1065.640-4.
    (2) Calculate the mean and standard deviation of all the Cd values
according to Eqs. 1065.602-1 and 1065.602-2.
    (3) If the standard deviation of all the Cd values is less than or
equal to 0.3% of the mean Cd, use the mean Cd in Eq. 1065.642-6, and
use the CFV only down to the lowest r measured during calibration using
the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.025

    (4) If the standard deviation of all the Cd values exceeds 0.3% of
the mean Cd, omit the Cd values corresponding to the data point
collected at the lowest r measured during calibration.
    (5) If the number of remaining data points is less than seven, take
corrective action by checking your calibration data or repeating the
calibration process. If you repeat the calibration process, we
recommend checking for leaks, applying tighter tolerances to
measurements and allowing more time for flows to stabilize.
    (6) If the number of remaining Cd values is seven or greater,
recalculate the mean and standard deviation of the remaining Cd values.
    (7) If the standard deviation of the remaining Cd values is less
than or equal to 0.3% of the mean of the remaining Cd, use that mean Cd
in Eq. 1065.642-6, and use the CFV values only down to the

lowest r associated with the remaining Cd.
    (8) If the standard deviation of the remaining Cd still exceeds
0.3% of the mean of the remaining Cd values, repeat the steps in
paragraph (e)(4) through (8) of this section.

0
112. Section 1065.642 is amended by revising paragraph (b) to read as
follows:

Sec.  1065.642  SSV, CFV, and PDP molar flow rate calculations.

    (b) SSV molar flow rate. Based on the Cd versus
Re equation you determined according to Sec.
1065.640, calculate SSV molar flow rate, n during an emission test as
follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.026

Example:

At = 0.01824 m\2\
pin = 99132 Pa
Z = 1
Mmix = 28.7805 g/mol = 0.0287805 kg/mol
R = 8.314472 J/(mol[middot]K)
Tin = 298.15 K
Re = 7.232[middot]10\\
y = 1.399
[beta] = 0.8
[Delta]p = 2.312 kPa
Using Eq. 1065.640-7,
rssv = 0.997
Using Eq. 1065.640-6,
Cf = 0.274
Using Eq. 1065.640-5,
Cd = 0.990
[GRAPHIC] [TIFF OMITTED] TR06MY08.027

n= 58.173 mol/s

* * * * *

0
113. A new Sec.  1065.644 is added to read as follows:

Sec.  1065.644  Vacuum-decay leak rate.

    This section describes how to calculate the leak rate of a vacuum-
decay leak verification, which is described in Sec.  1065.345(e). Use
Eq. 1065.644-1 to calculate the leak rate, nleak, and compare it to the
criterion specified in Sec.  1065.345(e).

[GRAPHIC] [TIFF OMITTED] TR06MY08.028

Where:

Vvac = geometric volume of the vacuum-side of the
sampling system.
R = molar gas constant.
p\2\ = Vacuum-side absolute pressure at time t\2\.
T\2\ = Vacuum-side absolute temperature at time t\2\.
p\1\ = Vacuum-side absolute pressure at time t\1\.
T\1\ = Vacuum-side absolute temperature at time t\1\.
t\2\ = time at completion of vacuum-decay leak verification test.
t\1\ = time at start of vacuum-decay leak verification test.

Example:

Vvac = 2.0000 L = 0.00200 m3
R = 8.314472 J/(mol[middot]K)
p\2\ = 50.600 kPa = 50600 Pa
T\2\ = 293.15 K
p\1\ = 25.300 kPa = 25300 Pa
T\1\ = 293.15 K
t\2\ = 10:57:35 AM
t\1\ = 10:56:25 AM
[GRAPHIC] [TIFF OMITTED] TR06MY08.029

0
114. Section 1065.645 is revised to read as follows:

Sec.  1065.645  Amount of water in an ideal gas.

    This section describes how to determine the amount of water in an
ideal gas, which you need for various performance verifications and
emission calculations. Use the equation for the vapor pressure of water
in paragraph (a) of this section or another appropriate equation and,
depending on whether you measure dewpoint or relative humidity, perform
one of the calculations in paragraph (b) or (c) of this section.
    (a) Vapor pressure of water. Calculate the vapor pressure of water
for a given saturation temperature condition, Tsat, as
follows, or use good engineering judgment to use a different
relationship of the vapor pressure of water to a given saturation
temperature condition:
    (1) For humidity measurements made at ambient temperatures from (0
to 100) [deg]C, or for humidity measurements made over super-cooled
water at ambient temperatures from (-50 to 0) [deg]C, use the following
equation:

[GRAPHIC] [TIFF OMITTED] TR06MY08.030

Where:

PH20 = vapor pressure of water at saturation temperature
condition, kPa.
Tsat = saturation temperature of water at measured
conditions, K.
Example:

Tsat = 9.5 [deg]C
Tdsat= 9.5 + 273.15 = 282.65 K
[GRAPHIC] [TIFF OMITTED] TR06MY08.112

-log10(pH20) = -0.073974
pH20 = 100.073974 = 1.18569 kPa

    (2) For humidity measurements over ice at ambient temperatures from
(-100 to 0) [deg]C, use the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.031

Example:

Tice = -15.4 [deg]C
Tice = -15.4 + 273.15 = 257.75 K
[GRAPHIC] [TIFF OMITTED] TR06MY08.032

-log10(pH2O) =-0.79821
pH2O = 100.79821 = 0.15914 kPa

    (b) Dewpoint. If you measure humidity as a dewpoint, determine the
amount of water in an ideal gas, xH2O, as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.033

Where:

xH2O = amount of water in an ideal gas.
pH2O = water vapor pressure at the measured dewpoint,
Tsat = Tdew.
pabs = wet static absolute pressure at the location of
your dewpoint measurement.
Example:
pabs = 99.980 kPa
Tsat = Tdew = 9.5 [deg]C
Using Eq. 1065.645-2,
pH2O = 1.18489 kPa
xH2O = 1.18489/99.980
xH2O = 0.011851 mol/mol

    (c) Relative humidity. If you measure humidity as a relative
humidity, RH %, determine the amount of water in an ideal gas,
xH2O, as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.034

Where:

xH2O = amount of water in an ideal gas.
RH % = relative humidity.
pH2O = water vapor pressure at 100% relative humidity at
the location of your relative humidity measurement, Tsat
= Tamb.
pabs = wet static absolute pressure at the location of
your relative humidity measurement.
Example:
RH % = 50.77%
pabs = 99.980 kPa

Tsat = Tamb = 20 [deg]C
Using Eq. 1065.645-2,
pH2O = 2.3371 kPa
xH2O = (50.77% [middot]2.3371)/99.980
xH2O = 0.011868 mol/mol

0
115. Section 1065.650 is revised to read as follows:

Sec.  1065.650  Emission calculations.

    (a) General. Calculate brake-specific emissions over each test
interval in a duty cycle. Refer to the standard-setting part for any
calculations you might need to determine a composite result, such as a
calculation that weights and sums the results of individual test
intervals in a duty cycle. For summations of continuous signals, each
indexed value (i.e., ``i'') represents (or approximates) the mean value
of the parameter for its respective time interval, delta-t.
    (b) We specify three alternative ways to calculate brake-specific
emissions, as follows:
    (1) For any testing, you may calculate the total mass of emissions,
as described in paragraph (c) of this section, and divide it by the
total work generated over the test interval, as described in paragraph
(d) of this section, using the following equation:

[GRAPHIC] [TIFF OMITTED] TR06MY08.035

Example:
mNOx = 64.975 g
W = 25.783 kW[middot]hr
eNOx = 64.975/25.783
eNOx = 2.520 g/(kW[middot]hr)

    (2) For discrete-mode steady-state testing, you may calculate the
ratio of emission mass rate to power, as described in paragraph (e) of
this section, using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.036

    (3) For field testing, you may calculate the ratio of total mass to
total work, where these individual values are determined as described
in paragraph (f) of this section. You may also use this approach for
laboratory testing, consistent with good engineering judgment. This is
a special case in which you use a signal linearly proportional to raw
exhaust molar flow rate to determine a value proportional to total
emissions. You then use the same linearly proportional signal to
determine total work using a chemical balance of fuel, intake air, and
exhaust as described in Sec.  1065.655, plus information about your
engine's brake-specific fuel consumption. Under this method, flow
meters need not meet accuracy specifications, but they must meet the
applicable linearity and repeatability specifications in subpart D or
subpart J of this part. The result is a brake-specific emission value
calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.037

Example:

m = 805.5 ~g
W = 52.102 ~kW[middot]hr
eCO = 805.5/52.102
eCO = 2.520 g/(kW[middot]hr)

    (c) Total mass of emissions. To calculate the total mass of an
emission, multiply a concentration by its respective flow. For all
systems, make preliminary calculations as described in paragraph (c)(1)
of this section, then use the method in paragraphs (c)(2) through (4)
of this section that is appropriate for your system. Calculate the
total mass of emissions as follows:
    (1) Concentration corrections. Perform the following sequence of
preliminary calculations on recorded concentrations:
    (i) Correct all THC and CH4 concentrations, including
continuous readings, sample bags readings, and dilution air background
readings, for initial contamination, as described in Sec.  1065.660(a).
    (ii) Correct all concentrations measured on a ``dry'' basis to a
``wet'' basis, including dilution air background concentrations, as
described in Sec.  1065.659.
    (iii) Calculate all THC and NMHC concentrations, including dilution
air background concentrations, as described in Sec.  1065.660.
    (iv) For emission testing with an oxygenated fuel, calculate any HC
concentrations, including dilution air background concentrations, as
described in Sec.  1065.665. See subpart I of this part for testing
with oxygenated fuels.
    (v) Correct all the NOX concentrations, including
dilution air background concentrations, for intake-air humidity as
described in Sec.  1065.670.
    (vi) Compare the background corrected mass of NMHC to background
corrected mass of THC. If the background corrected mass of NMHC is
greater than 0.98 times the background corrected mass of THC, take the
background corrected mass of NMHC to be 0.98 times the background
corrected mass of THC. If you omit the NMHC calculations as described
in Sec.  1065.660(b)(1), take the background corrected mass of NMHC to
be 0.98 times the background corrected mass of THC.
    (vii) Calculate brake-specific emissions before and after
correcting for drift, including dilution air background concentrations,
according to Sec.  1065.672.
    (2) Continuous sampling. For continuous sampling, you must
frequently record a continuously updated concentration signal. You may
measure this concentration from a changing flow rate or a constant flow
rate (including discrete-mode steady-state testing), as follows:
    (i) Varying flow rate. If you continuously sample from a changing
exhaust flow rate, time align and then multiply concentration
measurements by the flow rate from which you extracted it. Use good
engineering judgment to time align flow and concentration data to match
t50 rise or fall times to within 1 s. We
consider the following to be examples of changing flows that require a
continuous multiplication of concentration times molar flow rate: raw
exhaust, exhaust diluted with a constant flow rate of dilution air, and
CVS dilution with a CVS flowmeter that does not have an upstream heat
exchanger or electronic flow control. This multiplication results in
the flow rate of the emission itself. Integrate the emission flow rate
over a test interval to determine the total emission. If the total
emission is a molar quantity, convert this quantity to a mass by
multiplying it by its molar mass, M. The result is the mass of the
emission, m. Calculate m for continuous sampling with variable flow
using the following equations:
[GRAPHIC] [TIFF OMITTED] TR06MY08.038

Where:

[GRAPHIC] [TIFF OMITTED] TR06MY08.039

Example:

MNMHC = 13.875389 g/mol
N = 1200
xNMHC1 = 84.5 [mu]mol/mol = 84.5 [middot] 10-6
mol/mol
xNMHC2 = 86.0 [mu]mol/mol = 86.0 [middot] 10-6
mol/mol
nexh1 = 2.876 mol/s
nexh2 = 2.224 mol/s
frecord = 1 Hz
Using Eq. 1065.650-5,
[Delta]t = 1/1 =1 s
mNMHC = 13.875389 [middot] (84.5 [middot] 10-6
[middot] 2.876 + 86.0 [middot] 10-6 [middot] 2.224 + ...
+ xNMHC1200 [middot] nexh) [middot] 1
mNMHC = 25.53 g

    (ii) Constant flow rate. If you continuously sample from a constant
exhaust flow rate, use the same emission calculations described in
paragraph (c)(2)(i) of this section or calculate the mean or flow-
weighted concentration recorded over the test interval and treat the
mean as a batch sample, as described in paragraph (c)(3)(ii) of this
section. We consider the following to be examples of constant

exhaust flows: CVS diluted exhaust with a CVS flowmeter that has either
an upstream heat exchanger, electronic flow control, or both.
    (3) Batch sampling. For batch sampling, the concentration is a
single value from a proportionally extracted batch sample (such as a
bag, filter, impinger, or cartridge). In this case, multiply the mean
concentration of the batch sample by the total flow from which the
sample was extracted. You may calculate total flow by integrating a
changing flow rate or by determining the mean of a constant flow rate,
as follows:
    (i) Varying flow rate. If you collect a batch sample from a
changing exhaust flow rate, extract a sample proportional to the
changing exhaust flow rate. We consider the following to be examples of
changing flows that require proportional sampling: Raw exhaust, exhaust
diluted with a constant flow rate of dilution air, and CVS dilution
with a CVS flowmeter that does not have an upstream heat exchanger or
electronic flow control. Integrate the flow rate over a test interval
to determine the total flow from which you extracted the proportional
sample. Multiply the mean concentration of the batch sample by the
total flow from which the sample was extracted. If the total emission
is a molar quantity, convert this quantity to a mass by multiplying it
by its molar mass, M. The result is the mass of the emission, m. In the
case of PM emissions, where the mean PM concentration is already in
units of mass per mole of sample, MPM, simply multiply it by
the total flow. The result is the total mass of PM, mPM.
Calculate m for batch sampling with variable flow using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.040

Example:

MNOx = 46.0055 g/mol
N = 9000
xNOx = 85.6 [mu]mol/mol = 85.6 [middot]
10-6 mol/mol
ndexh1 = 25.534 mol/s
ndexh2 = 26.950 mol/s
frecord = 5 Hz
Using Eq. 1065.650-5,
[Delta]t = 1/5 = 0.2
mNOx = 46.0055 [middot] 85.6 [middot]
10-6 [middot] (25.534 + 26.950 + ... +
nexh9000) [middot] 0.2
mNOx = 4.201 g

    (ii) Constant flow rate. If you batch sample from a constant
exhaust flow rate, extract a sample at a proportional or constant flow
rate. We consider the following to be examples of constant exhaust
flows: CVS diluted exhaust with a CVS flow meter that has either an
upstream heat exchanger, electronic flow control, or both. Determine
the mean molar flow rate from which you extracted the constant flow
rate sample. Multiply the mean concentration of the batch sample by the
mean molar flow rate of the exhaust from which the sample was
extracted, and multiply the result by the time of the test interval. If
the total emission is a molar quantity, convert this quantity to a mass
by multiplying it by its molar mass, M. The result is the mass of the
emission, m. In the case of PM emissions, where the mean PM
concentration is already in units of mass per mole of sample,
MPM, simply multiply it by the total flow, and the result is
the total mass of PM, mPM. Calculate m for sampling with
constant flow using the following equations:
[GRAPHIC] [TIFF OMITTED] TR06MY08.041

and for PM or any other analysis of a batch sample that yields a mass
per mole of sample,
[GRAPHIC] [TIFF OMITTED] TR06MY08.042

Example:

MPM = 144.0 [mu]g/mol = 144.0 [middot] 10-6 g/
mol
ndexh = 57.692 mol/s
[Delta]t = 1200 s
mPM = 144.0 [middot] 10-6 [middot] 57.692
[middot]1200
mPM = 9.9692 g
    (4) Additional provisions for diluted exhaust sampling; continuous
or batch. The following additional provisions apply for sampling
emissions from diluted exhaust:
    (i) For sampling with a constant dilution ratio (DR) of diluted
exhaust versus exhaust flow (e.g., secondary dilution for PM sampling),
calculate m using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.043

Example:

mPMdil = 6.853 g
DR = 6:1
mPM = 6.853 [middot] (6)
mPM = 41.118 g

    (ii) For continuous or batch sampling, you may measure background
emissions in the dilution air. You may then subtract the measured
background emissions, as described in Sec.  1065.667.
    (d) Total work. To calculate total work from the engine's primary
output shaft, numerically integrate feedback power over a test
interval. Before integrating, adjust the speed and torque data for the
time alignment used in Sec.  1065.514(c). Any advance or delay used on
the feedback signals for cycle validation must also be used for
calculating work. Account for work of accessories according to Sec.
1065.110. Exclude any work during cranking and starting. Exclude work
during actual motoring operation (negative feedback torques), unless
the engine was connected to one or more energy storage devices.
Examples of such energy storage devices include hybrid powertrain
batteries and hydraulic accumulators, like the ones illustrated in
Figure 1 of Sec.  1065.210. Exclude any work during reference zero-load
idle periods (0% speed or idle speed with 0 N[middot]m reference
torque). Note, that there must be two consecutive reference zero load
idle points to establish a period where this applies. Include work
during idle points with simulated minimum torque such as Curb Idle
Transmissions Torque (CITT) for automatic transmissions in ``drive''.
The work calculation method described in paragraphs (b)(1) though (7)
of this section meets these requirements using rectangular integration.
You may use other logic that gives equivalent results. For example, you
may use a trapezoidal integration method as described in paragraph
(b)(8) of this section.
    (1) Time align the recorded feedback speed and torque values by the
amount used in Sec.  1065.514(c).
    (2) Calculate shaft power at each point during the test interval by
multiplying all the recorded feedback engine speeds by their respective
feedback torques.
    (3) Adjust (reduce) the shaft power values for accessories
according to Sec.  1065.110.
    (4) Set all power values during any cranking or starting period to
zero. See Sec.  1065.525 for more information about engine cranking.
    (5) Set all negative power values to zero, unless the engine was
connected to one or more energy storage devices. If the engine was
tested with an energy storage device, leave negative power values
unaltered.
    (6) Set all power values to zero during idle periods with a
corresponding reference torque of 0 N[middot]m.
    (7) Integrate the resulting values for power over the test
interval. Calculate total work as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.044

[GRAPHIC] [TIFF OMITTED] TR06MY08.045

Example:

N = 9000
fn1 = 1800.2 rev/min
fn2 = 1805.8 rev/min
T1 = 177.23 N[middot]m
T2 = 175.00 N[middot]m
Crev = 2 [middot] [pi] rad/rev
Ct1 = 60 s/min
Cp = 1000 (N[middot]m[middot]rad/s)/kW
frecord = 5 Hz
Ct2 = 3600 s/hr

[GRAPHIC] [TIFF OMITTED] TR06MY08.046

P1 = 33.41 kW
P2 = 33.09 kW
Using Eq. 1065.650-5,
[Delta]t = \1/5\ = 0.2 s
[GRAPHIC] [TIFF OMITTED] TR06MY08.047

W = 16.875 kW[middot]hr

    (8) You may use a trapezoidal integration method instead of the
rectangular integration described in this paragraph (b). To do this,
you must integrate the fraction of work between points where the torque
is positive. You may assume that speed and torque are linear between
data points. You may not set negative values to zero before running the
integration.
    (e) Steady-state mass rate divided by power. To determine steady-
state brake-specific emissions for a test interval as described in
paragraph (b)(2) of this section, calculate the mean steady-state mass
rate of the emission, m, and the mean steady-state power, P as follows:
    (1) To calculate m, multiply its mean concentration, x, by its
corresponding mean molar flow rate, n. If the result is a molar flow
rate, convert this quantity to a mass rate by multiplying it by its
molar mass, M. The result is the mean mass rate of the emission, m. In
the case of PM emissions, where the mean PM concentration is already in
units of mass per mole of sample, MPM, simply multiply it by
the mean molar flow rate, n. The result is the mass rate of PM,
mPM. Calculate m using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.048

    (2) Calculate P using the following equation:
    [GRAPHIC] [TIFF OMITTED] TR06MY08.049

    (3) Divide emission mass rate by power to calculate a brake-
specific emission result as described in paragraph (b)(2) of this
section.
    (4) The following example shows how to calculate mass of emissions
using mean mass rate and mean power:

MCO = 28.0101 g/mol

xCO = 12.00 mmol/mol = 0.01200 mol/mol

n = 1.530 mol/s

fn = 3584.5 rev/min = 375.37 rad/s

T = 121.50 N[middot]m

m = 28.0101[middot]0.01200[middot]1.530

m = 0.514 g/s = 1850.4 g/hr

P = 121.5[middot]375.37

P = 45607

W = 45.607 kW

eCO = 1850.4/45.61

eCO = 40.57 g/(kW[middot]hr)

    (f) Ratio of total mass of emissions to total work. To determine
brake-specific emissions for a test interval as described in paragraph
(b)(3) of this section, calculate a value proportional to the total
mass of each emission. Divide each proportional value by a value that
is similarly proportional to total work.
    (1) Total mass. To determine a value proportional to the total mass
of an emission, determine total mass as described in paragraph (c) of
this section, except substitute for the molar flow rate, n, or the
total flow, n, with a signal that is linearly proportional to molar
flow rate, [ntilde], or linearly proportional to total flow, [ntilde],
as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.050

    (2) Total work. To calculate a value proportional to total work
over a test interval, integrate a value that is proportional to power.
Use information about the brake-specific fuel consumption of your
engine, efuel, to convert a signal proportional to fuel flow
rate to a signal proportional to power. To determine a signal
proportional to fuel flow rate, divide a signal that is proportional to
the mass rate of carbon products by the fraction of carbon in your
fuel, wc.. For your fuel, you may use a measured
wc or you may use the default values in Table 1 of Sec.
1065.655. Calculate the mass rate of carbon from the amount of carbon
and water in the exhaust, which you determine with a chemical balance
of fuel, intake air, and exhaust as described in Sec.  1065.655. In the
chemical balance, you must use concentrations from the flow that
generated the signal proportional to molar flow rate, n~, in paragraph
(e)(1) of this section. Calculate a value proportional to total work as
follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.051

Where:
[GRAPHIC] [TIFF OMITTED] TR06MY08.052

    (3) Brake-specific emissions. Divide the value proportional to
total mass by the value proportional to total work to determine brake-
specific emissions, as described in paragraph (b)(3) of this section.
    (4) Example. The following example shows how to calculate mass of
emissions using proportional values:

N = 3000
frecord = 5 Hz
efuel = 285 g/(kW.hr)
wfuel = 0.869 g/g
Mc = 12.0107 g/mol
n1 = 3.922 ~mol/s = 14119.2 mol/hr
xCcombdry1 = 91.634 mmol/mol = 0.091634 mol/mol
xH2Oexh1 = 27.21 mmol/mol = 0.02721 mol/mol

Using Eq. 1065.650-5,
[Delta]t = 0.2 s

[GRAPHIC] [TIFF OMITTED] TR06MY08.053

W = 5.09 ~(kW[middot]hr)

    (g) Rounding. Round emission values only after all calculations are
complete and the result is in g/(kW[middot]hr) or units equivalent to
the units of the standard, such as g/(hp[middot]hr). See the definition
of ``Round'' in Sec.  1065.1001.

0
116. Section 1065.655 is revised to read as follows:

Sec.  1065.655  Chemical balances of fuel, intake air, and exhaust.

    (a) General. Chemical balances of fuel, intake air, and exhaust may
be used to calculate flows, the amount of water in their flows, and the
wet concentration of constituents in their flows. With one flow rate of
either fuel, intake air, or exhaust, you may use chemical balances to
determine the flows of the other two. For example, you may use chemical
balances along with either intake air or fuel flow to determine raw
exhaust flow.
    (b) Procedures that require chemical balances. We require chemical
balances when you determine the following:
    (1) A value proportional to total work, W, when you choose to
determine brake-specific emissions as described in Sec.  1065.650(e).
    (2) The amount of water in a raw or diluted exhaust flow,
xH2Oexh, when you do not measure the amount of water to
correct for the amount of water removed by a sampling system. Correct
for removed water according to Sec.  1065.659(c)(2).
    (3) The flow-weighted mean fraction of dilution air in diluted
exhaust, xdil/exh, when you do not measure dilution air flow
to correct for background emissions as described in Sec.  1065.667(c).
Note that if you use chemical balances for this purpose, you are
assuming that your exhaust is stoichiometric, even if it is not.
    (c) Chemical balance procedure. The calculations for a chemical
balance involve a system of equations that require iteration. We
recommend using a computer to solve this system of equations. You must
guess the initial values of up to three quantities: The amount of water
in the measured flow, xH2Oexh, fraction of dilution air in
diluted exhaust, xdil/exh, and the amount of products on a
C1 basis per dry mole of dry measured flow,
xCcombdry. You may use time-weighted mean values of
combustion air humidity and dilution air humidity in the chemical
balance; as long as your combustion air and dilution air humidities
remain within tolerances of  0.0025 mol/mol of their
respective mean values over the test interval. For each emission
concentration, x, and amount of water, xH2Oexh, you must
determine their completely dry concentrations, xdry and
xH2Oexhdry. You must also use your fuel's atomic hydrogen-
to-carbon ratio, [alpha], and oxygen-to-carbon ratio, [beta]. For your
fuel, you may measure [alpha] and [beta] or you may use the default
values in Table 1 of Sec.  1065.650. Use the following steps to
complete a chemical balance:
    (1) Convert your measured concentrations such as,
xCO2meas, xNOmeas, and xH2Oint, to dry
concentrations by dividing them by one minus the amount of water
present during their respective measurements; for example:
xH2OxCO2meas, xH2OxNOmeas, and
xH2Oint. If the amount of water present during a ``wet''
measurement is the same as the unknown amount of water in the exhaust
flow, xH2Oexh, iteratively solve for that value in the
system of equations. If you measure only total NOX and not
NO and NO2 separately, use good engineering judgment to
estimate a split in your total NOX concentration between NO
and NO2 for the chemical balances. For example, if you
measure emissions from a stoichiometric spark-ignition engine, you may
assume all NOX is NO. For a compression-ignition engine, you
may assume that your molar concentration of NOX,
xNOx, is 75% NO and 25% NO2. For NO2
storage aftertreatment systems, you may assume xNOx is 25%
NO and 75% NO\2\. Note that for calculating the mass of NOX
emissions, you must use the molar mass of NO2 for the
effective molar mass of all NOX species, regardless of the
actual NO2 fraction of NOX.
    (2) Enter the equations in paragraph (c)(4) of this section into a
computer program to iteratively solve for xH2Oexh,
xCcombdry, and xdil/exh. Use good engineering
judgment to guess initial values for xH2Oexh,
xCcombdry, and xdil/exh. We recommend guessing an
initial amount of water that is about twice the amount of water in your
intake or dilution air. We recommend guessing an initial value of
xCcombdry as the sum of your measured CO2, CO,
and THC values. We also recommend guessing an initial
xdil/exh between 0.75 and 0.95, such as 0.8. Iterate values
in the system of equations until the most recently updated guesses are
all within  1% of their respective most recently calculated
values.
    (3) Use the following symbols and subscripts in the equations for
this paragraph (c):

xdil/exh = Amount of dilution gas or excess air per mole
of exhaust.
xH2Oexh = Amount of water in exhaust per mole of exhaust.
xCcombdry = Amount of carbon from fuel in the exhaust per
mole of dry exhaust.
xH2Oexhdry = Amount of water in exhaust per dry mole of
dry exhaust.
xprod/intdry = Amount of dry stoichiometric products per
dry mole of intake air.
xdil/exhdry = Amount of dilution gas and/or
excess air per mole of dry exhaust.
xint/exhdry = Amount of intake air required to produce
actual combustion products per mole of dry (raw or diluted) exhaust.
xraw/exhdry = Amount of undiluted exhaust, without excess
air, per mole of dry (raw or diluted) exhaust.
xO2int = Amount of intake air O2 per mole of
intake air.
xCO2intdry = Amount of intake air CO2 per mole
of dry intake air. You may use xCO2intdry = 375 [mu]mol/
mol, but we recommend measuring the actual concentration in the
intake air.
xH2Ointdry = Amount of intake air H2O per mole
of dry intake air.
xCO2int = Amount of intake air CO2 per mole of
intake air.
xCO2dil = Amount of dilution gas CO2 per mole
of dilution gas.
xCO2dildry = Amount of dilution gas CO2 per
mole of dry dilution gas. If you use air as diluent, you may use
xCO2dildry = 375 [mu]mol/mol, but we recommend measuring
the actual concentration in the intake air.
xH2Odildry = Amount of dilution gas H2O per
mole of dry dilution gas.
xH2Odil = Amount of dilution gas H2O per mole
of dilution gas.
x[emission]meas = Amount of measured emission in the
sample at the respective gas analyzer.
x[emission]dry = Amount of emission per dry mole of dry
sample.
xH2O[emission]meas = Amount of water in sample at
emission-detection location. Measure or estimate these values
according to Sec.  1065.145(d)(2).
xH2Oint = Amount of water in the intake air, based on a
humidity measurement of intake air.
[alpha] = Atomic hydrogen-to-carbon ratio in fuel.
[beta] = Atomic oxygen-to-carbon ratio in fuel.

    (4) Use the following equations to iteratively solve for
xdil/exh, xH2Oexh, and xCcombdry:
[GRAPHIC] [TIFF OMITTED] TR06MY08.054

[GRAPHIC] [TIFF OMITTED] TR06MY08.055

[GRAPHIC] [TIFF OMITTED] TR06MY08.056

[GRAPHIC] [TIFF OMITTED] TR06MY08.057

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[GRAPHIC] [TIFF OMITTED] TR06MY08.067

[GRAPHIC] [TIFF OMITTED] TR06MY08.068

[GRAPHIC] [TIFF OMITTED] TR06MY08.069

[GRAPHIC] [TIFF OMITTED] TR06MY08.070

    (5) The following example is a solution for xdil/exh,
xH2Oexh, and xCcombdry using the equations in
paragraph (c)(4) of this section:
[GRAPHIC] [TIFF OMITTED] TR06MY08.071

[GRAPHIC] [TIFF OMITTED] TR06MY08.072

[GRAPHIC] [TIFF OMITTED] TR06MY08.073

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[GRAPHIC] [TIFF OMITTED] TR06MY08.085

[GRAPHIC] [TIFF OMITTED] TR06MY08.086

[GRAPHIC] [TIFF OMITTED] TR06MY08.087

[alpha] = 1.8
[beta] = 0.05

Table 1 of Sec.   1065.655.--Default Values of Atomic Hydrogen-to-Carbon Ratio, [alpha], Atomic Oxygen-to-Carbon
                     Ratio, [beta], and Carbon Mass Fraction of Fuel, wC, for Various Fuels
----------------------------------------------------------------------------------------------------------------
                                                                                Carbon mass
                      Fuel                           Atomic  hydrogen and  oxygen-to-carbon      concentration,
                                                            ratios  CH[alpha]O[beta]                 wC  g/g
----------------------------------------------------------------------------------------------------------------
Gasoline........................................  CH1.85O0                                                 0.866
2 Diesel...............................  CH1.80O0                                                 0.869
1 Diesel...............................  CH1.93O0                                                 0.861
Liquified Petroleum Gas.........................  CH2.64O0                                                 0.819
Natural gas.....................................  CH3.78O0.016                                             0.747
Ethanol.........................................  CH3O0.5                                                  0.521
Methanol........................................  CH4O1                                                    0.375
----------------------------------------------------------------------------------------------------------------

    (d) Calculated raw exhaust molar flow rate from measured intake air
molar flow rate or fuel mass flow rate. You may calculate the raw
exhaust molar flow rate from which you sampled emissions,
nexh, based on the measured intake air molar flow rate,
nint, or the measured fuel mass flow rate, nfuel,
and the values calculated using the chemical balance in paragraph (c)
of this section. Note that the chemical balance must be based on raw
exhaust gas concentrations. Solve for the chemical balance in paragraph
(c) of this section at the same frequency that you update and record
nintor nfuel.
    (1) Crankcase flow rate. If engines are not subject to crankcase
controls under the standard-setting part, you may calculate raw exhaust
flow based on nintor nfuel using one of the
following:
    (i) You may measure flow rate through the crankcase vent and
subtract it from the calculated exhaust flow.
    (ii) You may estimate flow rate through the crankcase vent by
engineering analysis as long as the uncertainty in your calculation
does not adversely affect your ability to show that your engines comply
with applicable emission standards.
    (iii) You may assume your crankcase vent flow rate is zero.
    (2) Intake air molar flow rate calculation. Based on
nint, calculate nexh as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.088

Where:

nexh = raw exhaust molar flow rate from which you
measured emissions.
nint = intake air molar flow rate including humidity in
intake air.

Example:

nint = 3.780 mol/s
xint/exhdry = 0.69021 mol/mol
xraw/exhdry = 1.10764 mol/mol
xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.089

nexh = 6.066 mol/s

    (3) Fuel mass flow rate calculation. Based on mfuel,
calculate nexh as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.090

Where:

nexh = raw exhaust molar flow rate from which you
measured emissions.
mfuel = fuel flow rate including humidity in intake air.

Example:

mfuel = 7.559 g/s
wC = 0.869 g/g
MC = 12.0107 g/mol
xCcombdry = 99.87 mmol/mol = 0.09987 mol/mol
xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.091

nexh = 6.066 mol/s

0
117. Section 1065.659 is revised to read as follows:

Sec.  1065.659  Removed water correction.

    (a) If you remove water upstream of a concentration measurement, x,
or upstream of a flow measurement, n, correct for the removed water.
Perform this correction based on the amount of water at the
concentration measurement, xH2O[emission]meas, and at the
flow meter, xH2Oexh, whose flow is used to determine the
concentration's total mass over a test interval.
    (b) When using continuous analyzers downstream of a sample dryer
for transient and ramped-modal testing, you must correct for removed
water using signals from other continuous analyzers. When using batch
analyzers downstream of a sample dryer, you must correct for removed
water by using signals either from other batch analyzers or from the
flow-weighted average concentrations from continuous analyzers.
Downstream of where you removed water, you may determine the amount of
water remaining by any of the following:
    (1) Measure the dewpoint and absolute pressure downstream of the
water removal location and calculate the amount of water remaining as
described in Sec.  1065.645.
    (2) When saturated water vapor conditions exist at a given
location, you may use the measured temperature at that location as the
dewpoint for the downstream flow. If we ask, you must demonstrate how
you know that saturated water vapor conditions exist. Use good
engineering judgment to measure the temperature at the appropriate
location to accurately reflect the dewpoint of the flow. Note that if
you use this option and the water correction in paragraph (d) of this
section results in a corrected value that is greater than the measured
value, your saturation assumption is invalid and you must determine the
water content according to paragraph (b)(1) of this section.
    (3) You may also use a nominal value of absolute pressure based on
an alarm set point, a pressure regulator set point, or good engineering
judgment.
    (4) Set xH2O[emission]meas equal to that of the measured
upstream humidity condition if it is lower than the dryer saturation
conditions.
    (c) For a corresponding concentration or flow measurement where you
did not remove water, you may determine the amount of initial water by
any of the following:
    (1) Use any of the techniques described in paragraph (b) of this
section.
    (2) If the measurement comes from raw exhaust, you may determine
the amount of water based on intake-air humidity, plus a chemical
balance of fuel, intake air and exhaust as described in Sec.  1065.655.
    (3) If the measurement comes from diluted exhaust, you may
determine the amount of water based on intake-air humidity, dilution
air humidity, and a chemical balance of fuel, intake air, and exhaust
as described in Sec.  1065.655.
    (d) Perform a removed water correction to the concentration
measurement using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.092

Example:

xCOmeas = 29.0 [mu]mol/mol
x H2OCOmeas = 8.601 mmol/mol = 0.008601 mol/mol
xH2Oexh = 34.04 mmol/mol = 0.03404 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.093

xCO = 28.3 [mu]mol/mol

0
118. Section 1065.660 is revised to read as follows:

Sec.  1065.660  THC and NMHC determination.

    (a) THC determination and THC/CH4 initial contamination
corrections. (1) If we require you to determine THC emissions,
calculate xTHC[THC-FID] using the initial THC contamination
concentration xTHC[THC-FID]init from Sec.  1065.520 as
follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.094

Example:

xTHCuncor = 150.3 [mu]mol/mol
xTHCinit = 1.1 [mu]mol/mol
xTHCcor = 150.3 - 1.1
xTHCcor = 149.2 [mu]mol/mol

    (2) For the NMHC determination described in paragraph (b) of this
section, correct xTHC[THC-FID] for initial HC contamination
using Eq. 1065.660-1. You may correct for initial contamination of the
CH4 sample train using Eq. 1065.660-1, substituting in
CH4 concentrations for THC.
    (b) NMHC determination. Use one of the following to determine NMHC
concentration, xNMHC:
    (1) If you do not measure CH4, you may determine NMHC
concentrations as described in Sec.  1065.650(c)(1)(vi).
    (2) For nonmethane cutters, calculate xNMHC using the
nonmethane cutter's penetration fractions (PF) of CH4 and
C2H6 from Sec.  1065.365, and using the HC
contamination and wet-to-dry corrected THC concentration
xTHC[THC-FID]cor as determined in paragraph (a) of this
section.
    (i) Use the following equation for penetration fractions determined
using an NMC configuration as outlined in Sec.  1065.365(d):
[GRAPHIC] [TIFF OMITTED] TR06MY08.095

Where:

xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
xTHC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
RFCH4[THC-FID] = response factor of THC FID to
CH4, according to Sec.  1065.360(d).
RFPFC2H6[NMC-FID] = nonmethane cutter combined ethane
response factor and penetration fraction, according to Sec.
1065.365(d).

Example:

xTHC[THC-FID]cor = 150.3 [mu]mol/mol
xTHC[NMC-FID] = 20.5 [mu]mol/mol
RFPFC2H6[NMC-FID] = 0.019
RFCH4[THC-FID] = 1.05
[GRAPHIC] [TIFF OMITTED] TR06MY08.096

xNMHC = 130.4 [mu]mol/mol

    (ii) For penetration fractions determined using an NMC
configuration as outlined in Sec.  1065.365(e), use the following
equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.097

Where:

xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
PFCH4[NMC-FID] = nonmethane cutter CH4
penetration fraction, according to Sec.  1065.365(e).
xTHC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
PFC2H6[NMC-FID] = nonmethane cutter ethane penetration
fraction, according to Sec.  1065.365(e).

Example:

xTHC[THC-FID]cor = 150.3 [mu]mol/mol
PFCH4[NMC-FID] = 0.990
xTHC[NMC-FID] = 20.5 [mu]mol/mol
PFC2H6[NMC-FID] = 0.020
[GRAPHIC] [TIFF OMITTED] TR06MY08.098

xNMHC = 132.3 [mu]mol/mol

    (iii) For penetration fractions determined using an NMC
configuration as outlined in Sec.  1065.365(f), use the following
equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.099

Where:

xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
PFCH4[NMC-FID] = nonmethane cutter CH4
penetration fraction, according to Sec.  1065.365(f).
xTHC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
RFPFC2H6[NMC-FID] = nonmethane cutter CH4
combined ethane response factor and penetration fraction, according
to Sec.  1065.365(f).
RFCH4[THC-FID] = response factor of THC FID to
CH4, according to Sec.  1065.360(d).

Example:

xTHC[THC-FID]cor = 150.3 [mu]mol/mol
PFCH4[NMC-FID] = 0.990
xTHC[NMC-FID] = 20.5 [mu]mol/mol
RFPFC2H6[NMC-FID] = 0.019
RFCH4[THC-FID] = 0.980
[GRAPHIC] [TIFF OMITTED] TR06MY08.100

xNMHC = 132.5 [mu]mol/mol

    (3) For a gas chromatograph, calculate xNMHC using the
THC analyzer's response factor (RF) for CH4, from Sec.
1065.360, and the HC contamination and wet-to-dry corrected initial THC
concentration xTHC[THC-FID]cor as determined in section (a)
above as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.101

Where:

xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID.
xCH4 = concentration of CH4, HC contamination
(optional) and dry-to-wet corrected, as measured by the gas
chromatograph FID.
RFCH4[THC-FID] = response factor of THC-FID to
CH4.

Example:

xTHC[THC-FID][cor = 145.6 [mu]mol/mol
RFCH4[THC-FID] = 0.970
xCH4 = 18.9 [mu]mol/mol
xNMHC = 145.6-0.970 [middot] 18.9
xNMHC = 127.3 [mu]mol/mol

0
119. Section 1065.665 is revised to read as follows:

Sec.  1065.665  THCE and NMHCE determination.

    (a) If you measured an oxygenated hydrocarbon's mass concentration,
first calculate its molar concentration in the exhaust sample stream
from which the sample was taken (raw or diluted exhaust), and convert
this into a C1-equivalent molar concentration. Add these
C1-equivalent molar concentrations to the molar
concentration of NOTHC. The result is the molar concentration of THCE.
Calculate THCE concentration using the following equations, noting that
equation 1065.665-3 is only required if you need to convert your OHC
concentration from mass to moles:

[GRAPHIC] [TIFF OMITTED] TR06MY08.102

[GRAPHIC] [TIFF OMITTED] TR06MY08.103

[GRAPHIC] [TIFF OMITTED] TR06MY08.104

Where:

xTHCE = The C1-equivalent sum of the
concentration of carbon mass contributions of non-oxygenated
hydrocarbons, alcohols, and aldehydes.
xNOTHC = The C1-equivalent sum of the
concentration of nonoxygenated THC.
xOHCi = The C1-equivalent concentration of
oxygenated species i in diluted exhaust, not corrected for initial
contamination.
xOHCi-init = The C1-equivalent concentration
of the initial system contamination (optional) of oxygenated species
i, dry-to-wet corrected.
xTHC[THC-FID]cor = The C1-equivalent response
to NOTHC and all OHC in diluted exhaust, HC contamination and dry-
to-wet corrected, as measured by the THC-FID.
RFOHCi[THC-FID] = The response factor of the FID to
species i relative to propane on a C1-equivalent basis.
C = The mean number of carbon atoms in the
particular compound.
Mdexh = The molar mass of diluted exhaust as determined
in Sec.  1065.340.
mdexhOHCi = The mass of oxygenated species i in dilute
exhaust.
MOHCi = The C1-equivalent molecular weight of
oxygenated species i.
mdexh = The mass of diluted exhaust.
ndexhOHCi = The number of moles of oxygenated species i
in total diluted exhaust flow.
ndexh = The total diluted exhaust flow.

    (b) If we require you to determine NMHCE, use the following
equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.105

Where:

xNMHCE = The C1-equivalent sum of the
concentration of carbon mass contributions of non-oxygenated NMHC,
alcohols, and aldehydes.
RFCH4[THC-FID] = response factor of THC-FID to
CH4.
xCH4 = concentration of CH4, HC contamination
(optional) and dry-to-wet corrected, as measured by the gas
chromatograph FID.

    (c) The following example shows how to determine NMHCE emissions
based on ethanol (C2H5OH), methanol
(CH3OH), acetaldehyde (C2H4O), and
formaldehyde (HCHO) as C1-equivalent molar concentrations:

xTHC[THC-FID]cor = 145.6 [mu]mol/mol
xCH4 = 18.9 [mu]mol/mol
xC2H5OH = 100.8 [mu]mol/mol
xCH3OH = 1.1 [mu]mol/mol
xC2H4O = 19.1 [mu]mol/mol
xHCHO = 1.3 [mu]mol/mol
RFCH4[THC-FID] = 1.07
RFC2H5OH[THC-FID] = 0.76
RFCH3OH[THC-FID] = 0.74
RFH2H4O[THC-FID] = 0.50
RFHCHO[THC-FID] = 0.0
xNMHCE = xTHC[THC-FID]cor-(xC2H5OH
[middot] RFC2H5OH[THC-FID] + xCH3OH [middot]
RFCH3OH[THC-FID] + xC2H4O [middot]
RFC2H4O[THC-FID] + xHCHO [middot]
RFHCHO[THC-FID] + xC2H5OH + xCH3OH +
xC2H4O + xHCHO-(RFCH4[THC-FID]
[middot] xCH4)
xNMHCE = 145.6-(100.8 [middot] 0.76 + 1.1 [middot] 0.74 +
19.1 [middot] 0.50 + 1.3 [middot] 0) + 100.8 + 1.1 + 19.1 + 1.3-(1.07
[middot] 18.9)
xNMHCE = 160.71 [mu]mol/mol

0
120. Section 1065.667 is amended by revising paragraph (b) to read as
follows:

Sec.  1065.667  Dilution air background emission correction.

* * * * *
    (b) You may determine the total flow of dilution air by a direct
flow measurement. In this case, calculate the total mass of background
as described in Sec.  1065.650(b), using the dilution air flow,
ndil. Subtract the background mass from the total mass. Use
the result in brake-specific emission calculations.
* * * * *

0
121. Section 1065.670 is amended by revising the introductory text to
read as follows:

Sec.  1065.670  NOX intake-air humidity and temperature corrections.

    See the standard-setting part to determine if you may correct
NOX emissions for the effects of intake-air humidity or
temperature. Use the NOX intake-air humidity and temperature
corrections specified in the standard-setting part instead of the
NOX intake-air humidity correction specified in this part
1065. If the standard-setting part does not prohibit correcting
NOX emissions for intake-air humidity according to this part
1065, first apply any NOX corrections for background
emissions and water removal from the exhaust sample, then correct
NOX concentrations for intake-air humidity. You may use a
time-weighted mean combustion air humidity to calculate this correction
if your combustion air humidity remains within a tolerance of  0.0025 mol/mol of the mean value over the test interval. For
intake-air humidity correction, use one of the following approaches:
* * * * *

0
122. Section 1065.675 is revised to read as follows:

Sec.  1065.675  CLD quench verification calculations.

    Perform CLD quench-check calculations as follows:
    (a) Calculate the amount of water in the span gas,
xH2Ospan, assuming

complete saturation at the span-gas temperature.
    (b) Estimate the expected amount of water and CO2 in the
exhaust you sample, xH2Oexp and xCO2exp,
respectively, by considering the maximum expected amounts of water in
combustion air, fuel combustion products, and dilution air
concentrations (if applicable).
    (c) Set xH2Oexp equal to xH2Omeas if you are
using a sample dryer that passes the sample dryer verification check in
Sec.  1065.342.
    (d) Calculate water quench as follows:

    [GRAPHIC] [TIFF OMITTED] TR06MY08.106

Where:

quench = amount of CLD quench.
xNOdry = measured concentration of NO upstream of a
bubbler, according to Sec.  1065.370.
xNOwet = measured concentration of NO downstream of a
bubbler, according to Sec.  1065.370.
xH2Oexp = expected maximum amount of water entering the
CLD sample port during emission testing.
xH2Omeas = measured amount of water entering the CLD
sample port during the quench verification specified in Sec.
1065.370.
xNO,CO2 = measured concentration of NO when NO span gas
is blended with CO2 span gas, according to Sec.
1065.370.
xNO,N2 = measured concentration of NO when NO span gas is
blended with N2 span gas, according to Sec.  1065.370.
xCO2exp = expected maximum amount of CO2
entering the CLD sample port during emission testing.
xCO2meas = measured amount of CO2 entering the
CLD sample port during the quench verification specified in Sec.
1065.370.

Example:

xNOdry = 1800.0 [mu]mol/mol
xNOwet = 1760.5 [mu]mol/mol
xH2Oexp = 0.030 mol/mol
xH2Omeas = 0.017 mol/mol
xNO,CO2 = 1480.2 [mu]mol/mol
xNO,N2 = 1500.8 [mu]mol/mol
xCO2exp = 2.00%
xCO2meas = 3.00%
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quench = -0.00888-0.00915 = -1.80%

0
123. Section 1065.690 is amended by revising paragraph (e) to read as
follows:

Sec.  1065.690  Buoyancy correction for PM sample media.

* * * * *
    (e) Correction calculation. Correct the PM sample media for
buoyancy using the following equations:
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Where:
mcor = PM mass corrected for buoyancy.
muncor = PM mass uncorrected for buoyancy.
Pair = density of air in balance environment.
Pweight = density of calibration weight used to span
balance.
Pmedia = density of PM sample media, such as a filter.

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Where:
pabs = absolute pressure in balance environment.
Mmix = molar mass of air in balance environment.
R = molar gas constant.
Tamb = absolute ambient temperature of balance
environment.

Example:
pabs = 99.980 kPa
Tsat = Tdew = 9.5 [deg]C
Using Eq. 1065.645-2,
pH20 = 1.1866 kPa
Using Eq. 1065.645-3,
xH2O = 0.011868 mol/mol
Using Eq. 1065.640-9,
Mmix = 28.83563 g/mol
R = 8.314472 J/(mol [middot] K)
Tamb = 20 [deg]C
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Pair = 1.18282 kg/m3
muncorr = 100.0000 mg
Pweight = 8000 kg/m3
Pmedia = 920 kg/m3
[GRAPHIC] [TIFF OMITTED] TR06MY08.111

mcor 100.1139 mg

0
124. Section 1065.695 is amended by revising paragraph (c)(7)(ix) to
read as follows:

Sec.  1065.695  Data requirements.

* * * * *
    (c) * * *
    (7) * * *
    (ix) Warm-idle speed value.
* * * * *

Subpart H--[Amended]

0
125. Section 1065.701 is amended by revising paragraphs (b), (c), and
(e) to read as follows:

Sec.  1065.701  General requirements for test fuels.

* * * * *
    (b) Fuels meeting alternate specifications. We may allow you to use
a different test fuel (such as California Phase 2 gasoline) if it does
not affect your ability to show that your engines would comply with all
applicable emission standards using the fuel specified in this subpart.
    (c) Fuels not specified in this subpart. If you produce engines
that run on a type of fuel (or mixture of fuels) that we do not specify
in this subpart, you must get our written approval to establish the
appropriate test fuel. See the standard-setting part for provisions
related to fuels and fuel mixtures not specified in this subpart.
    (1) For engines designed to operate on a single fuel, we will
generally allow you to use the fuel if you show us all the following
things are true:
    (i) Show that your engines will use only the designated fuel in
service.
    (ii) Show that this type of fuel is commercially available.
    (iii) Show that operating the engines on the fuel we specify would
be inappropriate, as in the following examples:
    (A) The engine will not run on the specified fuel.
    (B) The engine or emission controls will not be durable or work
properly when operating with the specified fuel.
    (C) The measured emission results would otherwise be substantially
unrepresentative of in-use emissions.
    (2) For engines that are designed to operate on different fuel
types, the provisions of paragraphs (c)(1)(ii) and (iii) of this
section apply with respect to each fuel type.
    (3) For engines that are designed to operate on different fuel
types as well as continuous mixtures of those fuels, we may require you
to test with either the worst-case fuel mixture or the most
representative fuel mixture, unless the standard-setting part specifies
otherwise.
* * * * *
    (e) Service accumulation and field testing fuels. If we do not
specify a service-accumulation or field-testing fuel in the standard-