(2) Measure roll runout using an indicator with a probe that allows
for measuring the position of the roll surface relative to the roll
centerline as it turns through a complete revolution. The indicator
must have some means of being securely mounted adjacent to the roll.
The indicator must have sufficient range to measure roll runout at all
points, with a minimum accuracy of 0.025 mm. Calibrate the
indicator according to the instrument manufacturer's instructions.
    (3) Position the indicator adjacent to the roll surface at the
desired measurement location. Position the shaft of the indicator
perpendicular to the roll such that the point of the indicator is
slightly touching the surface of the roll and can move freely through a
full rotation of the roll. Zero the indicator according to the
instrument manufacturer's instructions. Avoid distortion of the runout
measurement from the weight of a person standing on or near the mounted
dial indicator.
    (4) Slowly turn the roll through a complete rotation and record the
maximum and minimum values from the indicator. Calculate runout as the
difference between these maximum and minimum values.
    (5) Repeat the steps in paragraphs (c)(3) and (4) of this section
for all measurement locations.
    (6) The roll runout must be less than 0.254 mm (0.0100 inches) at
all measurement locations.
    (d) Diameter procedure. Verify roll diameter based on the following
procedure, or an equivalent procedure based on good engineering
judgment:
    (1) Prepare the laboratory and the dynamometer as specified in
paragraph (c)(1) of this section.
    (2) Measure roll diameter using a Pi Tape[supreg]. Orient the Pi
Tape[supreg] to the marker line at the desired measurement location
with the Pi Tape[supreg] hook pointed outward. Temporarily secure the
Pi Tape[supreg] to the roll near the hook end with adhesive tape.
Slowly turn the roll, wrapping the Pi Tape[supreg] around the roll
surface. Ensure that the Pi Tape[supreg] is flat and adjacent to the
marker line around the full circumference of the roll. Attach a 2.26-kg
weight to the hook of the Pi Tape[supreg] and position the roll so that
the weight dangles freely. Remove the adhesive tape without disturbing
the orientation or alignment of the Pi Tape[supreg].
    (3) Overlap the gage member and the vernier scale ends of the Pi
Tape[supreg] to read the diameter measurement to the nearest 0.01 mm.
Follow the manufacturer's recommendation to correct the measurement to
20 [deg]C, if applicable.
    (4) Repeat the steps in paragraphs (d)(2) and (3) of this section
for all measurement locations.
    (5) The measured roll diameter must be within 0.254 mm
of the specified nominal value at all measurement locations. You may
revise the nominal value to meet this specification, as long as you use
the corrected nominal value for all calculations in this subpart.

Sec.  1066.230  Time verification procedure.

    (a) Overview. This section describes how to verify the accuracy of
the dynamometer's timing device.
    (b) Scope and frequency. Perform this verification upon initial
installation and after major maintenance.

    (c) Procedure. Perform this verification using one of the following
procedures:
    (1) WWV method. You may use the time and frequency signal broadcast
by NIST from radio station WWV as the time standard if the trigger for
the dynamometer timing circuit has a frequency decoder circuit, as
follows:
    (i) Contact station WWV by telephone by dialing<PHONE_NUMBER> and
listen for the time announcement. Verify that the trigger started the
dynamometer timer. Use good engineering judgment to minimize error in
receiving the time and frequency signal.
    (ii) After at least 1000 seconds, re-dial station WWV and listen
for the time announcement. Verify that the trigger stopped the
dynamometer timer.
    (iii) Compare the measured elapsed time, yact, to the
corresponding time standard, yref, to determine the time
error, yerror, using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.144

    (2) Ramping method. You may use an operator-defined ramp function
to serve as the time standard as follows:
    (i) Set up a signal generator to output a marker voltage at the
peak of each ramp to trigger the dynamometer timing circuit. Output the
designated marker voltage to start the verification period.
    (ii) After at least 1000 seconds, output the designated marker
voltage to end the verification period.
    (iii) Compare the measured elapsed time between marker signals,
yact, to the corresponding time standard, yref,
to determine the time error, yerror, using Eq. 1066.230-1.
    (3) Dynamometer coastdown method. You may use a signal generator to
output a known speed ramp signal to the dynamometer controller to serve
as the time standard as follows:
    (i) Generate upper and lower speed values to trigger the start and
stop functions of the coastdown timer circuit. Use the signal generator
to start the verification period.
    (ii) After at least 1000 seconds, use the signal generator to end
the verification period.
    (iii) Compare the measured elapsed time between trigger signals,
yact, to the corresponding time standard, yref,
to determine the time error, yerror, using Eq. 1066.230-1.
    (d) Performance evaluation. The time error determined in paragraph
(c) of this section may not exceed 0.001%.

Sec.  1066.235  Speed verification procedure.

    (a) Overview. This section describes how to verify the accuracy of
the dynamometer speed determination. When performing this verification,
you must also verify the dynamometer speed at any devices used to
display or record vehicle speed (for example a driver's aid) is
representative of the speed input from the dynamometer speed
determination.
    (b) Scope and frequency. Perform this verification upon initial
installation, within 370 days before testing, and after major
maintenance.
    (c) Procedure. Use one of the following procedures to verify the
accuracy and resolution of the dynamometer speed simulation:
    (1) Pulse method. Connect a universal frequency counter to the
output of the dynamometer's speed-sensing device in parallel with the
signal to the dynamometer controller. The universal frequency counter
must be calibrated according to the counter manufacturer's instructions
and be capable of measuring with enough accuracy to perform the
procedure as specified in this paragraph (c)(1). Make sure the
instrumentation does not affect the signal to the dynamometer control
circuits. Determine the speed error as follows:
    (i) Set the dynamometer to speed-control mode. Set the dynamometer
speed to a value of approximately 4.5 m/s (10 mph); record the output
of the frequency counter after 10 seconds. Determine the roll speed,
vact, using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.045

Where:

f = frequency of the dynamometer speed sensing device, accurate to
at least four significant figures.
droll = nominal roll diameter, accurate to the nearest
1.0 mm, consistent with Sec.  1066.225(d).
n = the number of pulses per revolution from the dynamometer roll
speed sensor.

    Example:

f = 2.9231 Hz = 2.9231 s-1
droll = 904.40 mm = 0.90440 m
n = 1 pulse/rev
[GRAPHIC] [TIFF OMITTED] TP21MY13.046

    [ngr]act = 8.3053 m/s

    (ii) Repeat the steps in paragraph (c)(1)(i) of this section for
the maximum speed expected during testing and at least two additional
evenly spaced speed points between the starting speed and the maximum
speed point.
    (iii) Compare the calculated roll speed, vact, to each
corresponding speed set point, vref, to determine values for
speed error at each set point, verror, using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.047

Example:

vact = 8.3053 m/s
vref = 8.3000 m/s
verror = 8.3053-8.3000 = 0.0053 m/s

    (2) Frequency method. Install a piece of tape in the shape of an
arrowhead on the surface of the dynamometer roll near the outer edge.
Put a reference mark on the deck plate in line with the tape. Install a
stroboscope or photo tachometer on the deck plate and direct the flash
toward the tape on the roll. The stroboscope or photo tachometer must
be calibrated according to the instrument manufacturer's instructions
and be capable of measuring with enough accuracy to perform the
procedure as specified in this paragraph (c)(2). Determine the speed
error as follows:
    (i) Set the dynamometer to speed control mode. Set the dynamometer
speed to a speed value of approximately 4.5 m/s (10 mph). Tune the
stroboscope or photo tachometer until the signal matches the
dynamometer roll speed. Record the frequency. Determine the roll speed,
yact, using Eq. 1066.235-1, using the stroboscope or photo
tachometer's frequency for f.
    (ii) Repeat the steps in paragraph (c)(2)(i) of this section for
the maximum speed expected during testing and at least two additional
evenly spaced speed points between the starting speed and the maximum
speed point.
    (iii) Compare the calculated roll speed, vact, to each
corresponding speed set point, vref, to determine values for
speed error at each set point, yerror, using Eq. 1066.235-2.
    (d) Performance evaluation. The speed error determined in paragraph
(c) of this section may not exceed 0.02 m/s at any speed
set point.

Sec.  1066.240  Torque transducer verification.

    Verify torque-measurement systems by performing the verifications
described in Sec. Sec.  1066.270 and 1066.280.

Sec.  1066.245  Response time verification.

    (a) Overview. This section describes how to verify the
dynamometer's response time to a tractive effort force step change.
    (b) Scope and frequency. Perform this verification upon initial
installation,

within 370 days before testing (i.e., annually), and after major
maintenance.
    (c) Procedure. Use the dynamometer's automated process to verify
response time. You may perform this test either at two different
inertia settings corresponding approximately to the minimum and maximum
vehicle weights you expect to test or using base inertia and two
acceleration rates that cover the range of acceleration rates
experienced during testing (for example 0.5 and 8 mph/s). Use good
engineering judgment to select road-load coefficients representing
vehicles of the appropriate weight. Determine the dynamometer's
settling response time, ts, based on the point at which
there are no measured results more than 10% above or below the final
equilibrium value, as illustrated in Figure 1 of this section. The
observed settling response time must be less than 100 milliseconds for
each inertia setting.
[GRAPHIC] [TIFF OMITTED] TP21MY13.048

Sec.  1066.250  Base inertia verification.

    (a) Overview. This section describes how to verify the
dynamometer's base inertia.
    (b) Scope and frequency. Perform this verification upon initial
installation and after major maintenance (such as maintenance that
could affect roll assembly inertia).
    (c) Procedure. Verify the base inertia using the following
procedure:
    (1) Warm up the dynamometer according to the dynamometer
manufacturer's instructions. Set the dynamometer's road-load inertia to
zero, turning off any electrical simulation of road load and inertia so
that the base inertia of the dynamometer is the only inertia present,
and motor the rolls to 5 mph. Apply a constant force to accelerate the
roll at a nominal rate of 1 mph/s. Measure the elapsed time to
accelerate from 10 to 40 mph, noting the corresponding speed and time
points to the nearest 0.01 mph and 0.01 s. Also determine average force
over the measurement interval.
    (2) Starting from a steady roll speed of 45 mph, apply a constant
force to the roll to decelerate the roll at a nominal rate of 1 mph/s.
Measure the elapsed time to decelerate from 40 to 10 mph, noting the
corresponding speed and time points to the nearest 0.01 mph and 0.01 s.
Also determine average force over the measurement interval.
    (3) Repeat the steps in paragraphs (c)(1) and (2) of this section
for a total of five sets of results at the nominal acceleration rate
and the nominal deceleration rate.
    (4) Use good engineering judgment to select two additional
acceleration and deceleration rate pairs that cover the middle and
upper rates expected during testing. Repeat the steps in paragraphs
(c)(1) through (3) of this section at each of these additional
acceleration and deceleration rates.
    (5) Determine the base inertia, Ib, for each measurement
interval using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.049

Where:

F = average dynamometer force over the measurement interval as
measured by the dynamometer.
vfinal = roll surface speed at the end of the measurement
interval to the nearest 0.01 mph.
vinitial = roll surface speed at the start of the
measurement interval to the nearest 0.01 mph.
[Dgr]t = elapsed time during the measurement interval to
the nearest 0.01 s.

Example:

F = 1.500 lbf = 48.26 ft[middot]lbm/s\2\
vfinal = 40.00 mph = 58.67 ft/s
vinitial = 10.00 mph = 14.67 ft/s
[Dgr]t = 30.00 s
[GRAPHIC] [TIFF OMITTED] TP21MY13.050

Ib = 32.90 lbm

    (6) Calculate the base inertia error, Iberror, for each
of the thirty measured base inertia values, Ib, by comparing
it to the manufacturer's stated base inertia, Ibref, using
the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.051

Example:

Ibref = 32.96 lbm
Ibact = 32.90 lbm (from paragraph (c)(5) of this section)

[GRAPHIC] [TIFF OMITTED] TP21MY13.052

Iberror = 0.18%

    (7) Determine the base inertia arithmetic mean value,
Ib, from the ten acceleration and deceleration interval base
inertia values for each of the three acceleration/deceleration rates.
Then determine the base inertia arithmetic mean value, Ib,
from the three acceleration/deceleration rate mean base inertia values.
Calculate base inertia mean values as described in 40 CFR 1065.602(b).
    (8) Calculate the inertia error for the final mean base inertia
value from paragraph (c)(7) of this section. Use Eq. 1066.250-2,
substituting the final mean base inertia value from paragraph (c)(7) of
this section for the individual base inertia.
    (d) Performance evaluation. The dynamometer must meet the following
specifications to be used for testing under this part:
    (1) All base inertia errors determined under paragraph (c)(6) of
this section may not exceed 1.0%.
    (2) The mean base inertia error determined under paragraph (c)(8)
of this section may not exceed 0.20%.

Sec.  1066.255  Parasitic loss verification.

    (a) Overview. Verify the dynamometer's parasitic loss as described
in this section, and correct as necessary. This procedure determines
the dynamometer's internal losses that it must overcome to simulate
road load. Characterize these losses in a parasitic loss curve that the
dynamometer uses to apply compensating forces to maintain the desired
road-load force at the roll surface.
    (b) Scope and frequency. Perform this verification upon initial
installation, after major maintenance, and upon failure of a
verification in either Sec.  1066.270 or Sec.  1066.280.
    (c) Procedure. Perform this verification by following the
dynamometer manufacturer's specifications to establish a parasitic loss
curve, taking data at fixed speed intervals to cover the range of
vehicle speeds that will occur during testing. You may zero the load
cell at a selected speed if that improves your ability to determine the
parasitic loss. Parasitic loss forces may never be negative. Note that
the torque transducers must be zeroed and spanned prior to performing
this procedure.
    (d) Performance evaluation. Some dynamometers automatically updates
the parasitic loss curve for further testing. If this is not the case,
compare the new parasitic loss curve to the original parasitic loss
curve from the dynamometer manufacturer or the most recent parasitic
loss curve you programmed into the dynamometer. You may reprogram the
dynamometer to accept the new curve in all cases, and you must
reprogram the dynamometer if any point on the new curve departs from
the earlier curve by more than 9.0 N for dynamometers
capable of testing vehicles at or below 20,000 pounds GVWR or 36.0 N (8.0 lbf) for dynamometers not capable of
testing vehicles at or below 20,000 pounds GVWR.

Sec.  1066.260  Parasitic friction compensation evaluation.

    (a) Overview. This section describes how to verify the accuracy of
the dynamometer's friction compensation.
    (b) Scope and frequency. Perform this verification upon initial
installation, after major maintenance, and upon failure of a
verification in either Sec.  1066.270 or Sec.  1066.280. Note that this
procedure relies on proper calibration of speed and torque, as
described in Sec. Sec.  1066.235 and 1066.240. You must also first
verify the dynamometer's parasitic loss curve as specified in Sec.
1066.255.
    (c) Procedure. Use the following procedure to verify the accuracy
of the dynamometer's friction compensation:
    (1) Warm up the dynamometer as specified by the dynamometer
manufacturer.
    (2) Perform a torque verification as specified by the dynamometer
manufacturer. For torque verifications relying on shunt procedures, if
the results do not conform to specifications, recalibrate the
dynamometer using NIST-traceable standards as appropriate until the
dynamometer passes the torque verification. Do not change the
dynamometer's base inertia to pass the torque verification.
    (3) Set the dynamometer inertia to the base inertia with the road-
load coefficients A, B, and C set to 0. Set the dynamometer to speed-
control mode with a target speed of 50 mph or a higher speed
recommended by the dynamometer manufacturer. Once the speed stabilizes
at the target speed, switch the dynamometer from speed control to
torque control and allow the roll to coast for 60 seconds. Record the
initial and final speeds and the corresponding start and stop times. If
friction compensation is executed perfectly, there will be no change in
speed during the measurement interval.
    (4) Calculate the power equivalent of friction compensation error,
FCerror, using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.053

Where:

I = dynamometer inertia setting.
t = duration of the measurement interval, accurate to at least 0.01
s.
vinit = the roll speed corresponding to the start of the
measurement interval, accurate to at least 0.05 mph.
vfinal = the roll speed corresponding to the end of the
measurement interval, accurate to at least 0.05 mph.

Example:

I = 2000 lbm = 62.16 lbf[middot] s\2\/ft
t = 60.0 s
vinit = 9.2 mph = 13.5 ft/s
vfinal = 10.0 mph = 14.7 ft/s
[GRAPHIC] [TIFF OMITTED] TP21MY13.054

FCerror = -16.5 ft[middot]lbf/s = -0.031 hp

    (5) The friction compensation error may not exceed 0.15
hp for dynamometers capable of testing vehicles at or below 20,000
pounds GVWR, or 0.6 hp for dynamometers not capable of
testing vehicles at or below 20,000 pounds GVWR.

Sec.  1066.265  Acceleration and deceleration verification.

    (a) Overview. This section describes how to verify the
dynamometer's ability to achieve targeted acceleration and deceleration
rates. Paragraph (c) of this section describes how this verification
applies when the dynamometer is programmed directly for a specific
acceleration or deceleration rate. Paragraph (d) of this section
describes how this verification applies when the dynamometer is
programmed with a calculated force to achieve a targeted acceleration
or deceleration rate.
    (b) Scope and frequency. Perform this verification or an equivalent
procedure upon initial installation and after major maintenance that
could affect acceleration and deceleration accuracy. Note that this
procedure relies on proper calibration of speed as described in Sec.
1066.235.
    (c) Verification of acceleration and deceleration rates. Activate
the dynamometer's function generator for measuring roll revolution
frequency. If the dynamometer has no such function generator, set up a
properly calibrated external function generator consistent with the
verification described in this paragraph (c). Use the function
generator to determine actual acceleration and deceleration rates as
the dynamometer traverses speeds between 10 and 40 mph at various

nominal acceleration and deceleration rates. Verify the dynamometer's
acceleration and deceleration rates as follows:
    (1) Set up start and stop frequencies specific to your dynamometer
by identifying the roll-revolution frequency, f, in revolutions per
second (or Hz) corresponding to 10 mph and 40 mph vehicle speeds,
accurate to at least four significant figures, using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.055

Where:
v = the target roll speed, in inches per second (corresponding to
drive speeds of 10 mph or 40 mph).
n = the number of pulses from the dynamometer's roll-speed sensor
per roll revolution.
droll = roll diameter, in inches.

    (2) Program the dynamometer to accelerate the roll at a nominal
rate of 1 mph/s from 10 mph to 40 mph. Measure the elapsed time to
reach the target speed, to the nearest 0.01 s. Repeat this measurement
for a total of five runs. Determine the actual acceleration rate for
each run, aact, using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.056

Where:

aact = acceleration rate (decelerations have negative
values).
vfinal = the target value for the final roll speed.
vinit = the setpoint value for the initial roll speed.
t = time to accelerate from vinit to vfinal.

Example:

vfinal = 40 mph
vinit = 10 mph
t = 30.003 s
[GRAPHIC] [TIFF OMITTED] TP21MY13.057

aact = 0.999 mph/s

    (3) Program the dynamometer to decelerate the roll at a nominal
rate of 1 mph/s from 40 mph to 10 mph. Measure the elapsed time to
reach the target speed, to the nearest 0.01 s. Repeat this measurement
for a total of five runs. Determine the actual acceleration rate,
aact, using Eq. 1066.265-2
    (4) Repeat the steps in paragraphs (c)(2) and (3) of this section
for additional acceleration and deceleration rates in 1 mph/s
increments up to and including one increment above the maximum
acceleration rate expected during testing. Average the five repeat runs
to calculate a mean acceleration rate, aact, at each
setting.
    (5) Compare each mean acceleration rate, aact, to the
corresponding nominal acceleration rate, aref, to determine
values for acceleration error, aerror, using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.058

Example:

aact> = 0.999 mph/s
aref = 1 mph/s
[GRAPHIC] [TIFF OMITTED] TP21MY13.059

aerror = -0.100%
    (d) Verification of forces for controlling acceleration and
deceleration. Program the dynamometer with a calculated force value and
determine actual acceleration and deceleration rates as the dynamometer
traverses speeds between 10 and 40 mph at various nominal acceleration
and deceleration rates. Verify the dynamometer's ability to achieve
certain acceleration and deceleration rates with a given force as
follows:
    (1) Calculate the force setting, F, using the following equation:

    [GRAPHIC] [TIFF OMITTED] TP21MY13.060

Where:

Ib = the dynamometer manufacturer's stated base inertia,
in lbf[middot]s2/ft.
a = nominal acceleration rate, in ft/s\2\.

Example:

Ib = 2967 lbm = 92.217 lbf[middot] s\2\/ft
a = 1 mph/s = 1.4667 ft/s\2\
F= 92.217 [middot] [verbarlm]1.4667[verbarlm]
F = 135.25 lbf

    (2) Set the dynamometer to road-load mode and program it with a
calculated force to accelerate the roll at a nominal rate of 1 mph/s
from 10 mph to 40 mph. Measure the elapsed time to reach the target
speed, to the nearest 0.01 s. Repeat this measurement for a total of
five runs. Determine the actual acceleration rate, aact, for
each run using Eq. 1066.265-2. Repeat this step to determine measured
``negative acceleration'' rates using a calculated force to decelerate
the roll at a nominal rate of 1 mph/s from 40 mph to 10 mph. Average
the five repeat runs to calculate a mean acceleration rate,
aact, at each setting.
    (3) Repeat the steps in paragraph (d)(2) of this section for
additional acceleration and deceleration rates as specified in
paragraph (c)(4) of this section.
    (4) Compare each mean acceleration rate, aact, to the
corresponding nominal acceleration rate, aref, to determine
values for acceleration error, aerror, using Eq. 1066.265-3
    (e) Performance evaluation. The acceleration error from paragraphs
(c)(5) and (d)(4) of this section may not exceed 1.0%.

Sec.  1066.270  Unloaded coastdown verification.

    (a) Overview. Use force measurements to verify the dynamometer's
settings based on coastdown procedures.
    (b) Scope and frequency. Perform this verification upon initial
installation, within 7 days of testing, and after major maintenance.
    (c) Procedure. This procedure verifies the dynamometer's settings
derived from coastdown testing. For dynamometers that have an automated
process for this procedure, perform this evaluation by setting the
initial speed, final speed, inertial coefficients, and road-load
coefficients as required for each test, using good engineering judgment
to ensure that these values properly represent in-use operation. Use
the following procedure if your dynamometer does not perform this
verification with an automated process:
    (1) Warm up the dynamometer as specified by the dynamometer
manufacturer.
    (2) With the dynamometer in coastdown mode, set the dynamometer
inertia for the smallest vehicle weight that you expect to test and set
A, B, and C road-load coefficients to values typical of those used
during testing. Program the dynamometer to coast down over the
dynamometer operational speed range (typically from a speed of 80 mph
through a minimum speed at or below 10 mph). Perform at least one
coastdown over this speed range, collecting data over each 10 mph
interval.
    (3) Repeat the steps in paragraph (c)(2) of this section with the
dynamometer inertia and road-load coefficients set for the largest
vehicle weight that you expect to test.
    (4) Determine the average coastdown force, F, for each speed and
inertia setting for each of the coastdowns performed using the
following equation:

[GRAPHIC] [TIFF OMITTED] TP21MY13.061

Where:

F = the average force measured during the coastdown for each speed
interval and inertia setting, expressed in lbf[middot] s\2\/ft and
rounded to four significant figures.
I = the dynamometer's inertia setting, in lbf[middot] s\2\/ft.
vinit = the speed at the start of the coastdown,
expressed in ft/s and rounded to four significant figures.
vfinal = the speed at the end of the coastdown interval,
rounded to four significant figures.
t = coastdown time for each speed and inertia setting, accurate to
at least 0.01 s.

Example:

I = 2000 lbm = 65.17 lbf [middot] s\2\/ft
vinit = 25 mph = 36.66 ft/s
vfinal = 15 mph = 22.0 ft/s
t = 5.00 s
[GRAPHIC] [TIFF OMITTED] TP21MY13.062

F = 191.1 lbf

    (5) Calculate the target value of coastdown force, Fref,
based on the applicable dynamometer parameters for each speed and
inertia setting.
    (6) Compare the mean value of the coastdown force measured for each
speed and inertia setting, Fact, to the corresponding
Fref to determine values for coastdown force error,
Ferror, using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.063

Example:

Fref = 192 lbf
Fact = 191 lbf
[GRAPHIC] [TIFF OMITTED] TP21MY13.064

Ferror = 0.5%

    (d) Performance evaluation. The coastdown force error determined in
paragraph (c) of this section may not exceed the following:
    (1) For vehicles at or below 20,000 pounds GVWR, calculate
Ferrormax from the following formula:
[GRAPHIC] [TIFF OMITTED] TP21MY13.065

Example:

Fref = 192 lbf
Ferrormax (%) = (2.2/192)[middot]100 = 1.14%

    (2) For vehicles above 20,000 pounds GVWR, the maximum allowable
error, Ferrormax, for all speed and inertia settings is
1.0% or 39.2 N, whichever is greater.
    (e) If the dynamometer is not able to meet this requirement,
diagnose and repair the dynamometer before continuing with emission
testing. Diagnosis should include performing the verifications in Sec.
1066.255 and Sec.  1066.260.

Sec.  1066.280  Daily dynamometer readiness verification.

    (a) Overview. This section describes how to verify that the
dynamometer is ready for emission testing.
    (b) Scope and frequency. Perform this verification upon initial
installation, within 1 day before testing, and after major maintenance.
    (c) Procedure. For dynamometers that have an automated process for
this verification procedure, perform this evaluation by setting the
initial speed and final speed and the inertial and road-load
coefficients as required for the test, using good engineering judgment
to ensure that these values properly represent in-use operation. Use
the following procedure if your dynamometer does not perform this
verification with an automated process:
    (1) With the dynamometer in coastdown mode, set the dynamometer
inertia to the base inertia with the road-load coefficient A set to 20
lbf (or a force that results in a coastdown time of less than 10
minutes) and coefficients B and C set to 0. Program the dynamometer to
coast down for one 10 mph interval from 55 mph down to 45 mph. If your
dynamometer is not capable of performing one discrete coastdown, then
coast down with preset 10 mph intervals that include a 55 mph to 45 mph
interval.
    (2) Perform the coastdown.
    (3) Determine the coastdown force and coastdown force error using
Eqs. 1066.270-1 and 1066.270-2.
    (d) Performance evaluation. The coastdown force error determined in
paragraph (c) of this section may not exceed the following:
    (1) For vehicles at or below 20,000 pounds GVWR, 1.0%
or 9.8 N (2.2 lbf), whichever is greater.
    (2) For vehicles above 20,000 pounds GVWR, 1.0% or
39.2 N (8.8 lbf), whichever is greater.
    (e) If the verification results fail to meet the performance
criteria in paragraph (d) of this section, perform the procedure up to
two additional times. If the dynamometer is consistently unable to meet
the performance criteria, diagnose and repair the dynamometer before
continuing with emission testing. Diagnosis should include performing
the verifications in Sec.  1066.255 and Sec.  1066.260.

Sec.  1066.290  Driver's aid.

    Use good engineering judgment to provide a driver's aid that
facilitates compliance with the requirements of Sec.  1066.430. Verify
the speed accuracy of the driver's aid as described in Sec.  1066.235.

Subpart D--Coastdown

Sec.  1066.301  Overview of coastdown procedures.

    (a) The coastdown procedures described in this subpart are used to
determine the load coefficients (A, B, and C) for the simulated road-
load equation in Sec.  1066.210(d)(3).
    (b) The general procedure for performing coastdown tests and
calculating load coefficients is described in SAE J1263 and SAE J2263
(incorporated by reference in Sec.  1066.1010). This subpart specifies
certain deviations from those procedures for certain applications.
    (c) Use good engineering judgment for all aspects of coastdown
testing. For example, minimize the effects of grade by performing
coastdown testing on reasonably level surfaces and determining
coefficients based on average values from vehicle operation in opposite
directions over the course.

Sec.  1066.305  Coastdown procedures for motor vehicles at or below
14,000 pounds GVWR.

    For motor vehicles at or below 14,000 pounds GVWR, develop
representative road-load coefficients to characterize each test
vehicle. Calculate road-load coefficients by performing coastdowns
using the provisions of SAE J1263 and SAE J2263 (incorporated by
reference in Sec.  1066.1010). Perform coastdowns at a starting speed
as specified in SAE J2263, or at the highest speed from the range of
applicable duty cycles. Use the same road-load coefficients for all
duty cycles. However, if your test conditions are substantially
different from the conditions represented by your road-load
coefficients, such as cold-temperature testing, you may use good
engineering judgment to develop separate road-load coefficients.

Sec.  1066.310  Coastdown procedures for vehicles above 14,000 pounds
GVWR.

    This section describes coastdown procedures that are unique to
vehicles

above 14,000 pounds GVWR. These procedures are valid for calculating
road-load coefficients for chassis and post-transmission powerpack
testing and for calculating drag area (CDA) for use in the GEM
simulation tool under 40 CFR part 1037.
    (a) Determine load coefficients by performing a minimum of 16 valid
coastdown runs (8 in each direction).
    (b) Follow the provisions of Sections 1 through 9 of SAE J1263, and
SAE J2263 (incorporated by reference in Sec.  1066.1010), except as
described in this paragraph (b). The terms and variables identified in
this paragraph (b) have the meaning given in SAE J1263 or J2263 unless
specified otherwise.
    (1) The test condition specifications of SAE J1263 apply except as
follows for wind and road conditions:
    (i) We recommend that you do not perform coastdown testing on days
for which winds are forecast to exceed 6.0 mph.
    (ii) The grade of the test track or road must not be excessive
(considering factors such as road safety standards and effects on the
coastdown results). Road conditions should follow Section 7.4 of SAE
J1263, except that road grade may exceed 0.5%. If road grade is greater
than 0.02% over the length of the test surface, then the road grade as
a function of distance along the length of the test surface must be
incorporated into the analysis. To calculate the force due to grade use
Section 11.5 of SAE J2263.
    (2) Operate the vehicle at a top speed above 70 mph, or at its
maximum achievable speed if it cannot reach 70 mph. If a vehicle is
equipped with a vehicle speed limiter that is set for a maximum speed
below 70 mph, you must disable the vehicle speed limiter. Start the
test at or above 70 mph or at the vehicle's maximum achievable speed if
it cannot reach 70 mph. Collect data through a minimum speed at or
below 15 mph. Data analysis for valid coastdown runs must include a
maximum speed as described in this paragraph (b)(2) and a minimum speed
of 15 mph.
    (3) Gather data regarding wind speed and direction, in coordination
with time-of-day data, using at least one stationary electro-mechanical
anemometer and suitable data loggers meeting the specifications of SAE
J1263, as well as the following additional specifications for the
anemometer placed adjacent to the test surface:
    (i) Calibrate the equipment by running the zero-wind and zero-angle
calibrations within 24 hours before conducting the coastdown
procedures. If the coastdown procedures are not complete 24 hours after
calibrating the equipment, repeat the calibration for another 24 hours
of data collection.
    (ii) Record the location of the anemometer using a GPS measurement
device adjacent to the test surface (approximately) at the midway
distance along the test surface used for coastdowns.
    (iii) Position the anemometer such that it will be at least 2.5 but
not more than 3.0 vehicle widths from the test vehicle's centerline as
the test vehicle passes the location of that anemometer.
    (iv) Mount the anemometer at a height that is within 6 inches of
half the test vehicle's maximum height.
    (v) Place the anemometer at least 50 feet from the nearest tree and
at least 25 feet from the nearest bush (or equivalent roadside
features).
    (vi) The height of the grass surrounding the stationary anemometer
may not exceed 10% of the anemometer's mounted height, within a radius
equal to the anemometer's mounted height.
    (4) You may split runs as per Section 9.3.1 of SAE J2263, but we
recommend whole runs. If you split a run, analyze each portion
separately, but count the split runs as one run with respect to the
minimum number of runs required.
    (5) You may perform consecutive runs in a single direction,
followed by consecutive runs in the opposite direction, consistent with
good engineering judgment. Harmonize starting and stopping points to
the extent practicable to allow runs to be paired.
    (6) All valid coastdown run times in each direction must be within
2.0 standard deviations of the mean of the valid coastdown run times
(from 70 mph down to 15 mph) in that direction. Eliminate runs outside
this range. After eliminating these runs you must have at least eight
valid runs in each direction. You may use coastdown run times that do
not meet these standard deviation requirements if we approve it in
advance. In your request, describe why the vehicle is not able to meet
the specified standard deviation requirements and propose an
alternative set of requirements.
    (7) Analyze data for chassis and post-transmission powerpack
testing or for use in the GEM simulation tool as follows:
    (i) Follow the procedures specified in Section 10 of SAE J1263 or
Section 11 of SAE J2263 to calculate coefficients for chassis and post-
transmission powerpack testing.
    (ii) Determine drag area, CDA as follows instead of using the
procedure specified in Section 10 of SAE J1263:
    (A) Measure vehicle speed at fixed intervals over the coastdown run
(generally at 10 Hz), including speeds at or above 15 mph and at or
below 70 mph. Establish the height or altitude corresponding to each
interval as described in SAE J2263 if you need to incorporate the
effects of road grade.
    (B) Calculate the vehicle's effective mass, Me, in kg by
adding 56.7 kg to the measured vehicle mass for each tire making road
contact. This accounts for the rotational inertia of the wheels and
tires.
    (C) Calculate the road-load force for each measurement interval,
Fi, for values of i >= 1 using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.066

Where:

Me = the vehicle's effective mass, expressed to at least
the nearest 0.1 kg.
v = vehicle speed at the beginning and end of the measurement
interval.
[Delta]t = elapsed time over the measurement interval, in seconds.

    (D) Plot the data from all the coastdown runs on a single plot of
Fi vs. vi\2\ to determine the slope correlation,
D, based on the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.067

Where:

g = gravitational acceleration = 9.81 m/s\2\.
[Delta]h = change in height or altitude over the measurement
interval, in m. Assume [Delta]h = 0 if you are not correcting for
grade.
[Delta]s = distance the vehicle travels down the road during the
measurement interval, in m.
Am = the calculated value of the y-intercept based on the
curve-fit.

    (E) Calculate drag area, CDA, in m\2\ using the
following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.068

Where:

[rho] = air density at reference conditions = 1.17 kg/m\3\.

[GRAPHIC] [TIFF OMITTED] TP21MY13.069

Tb,= average ambient absolute temperature during testing,
in K.
Pb,= average ambient pressuring during the test, in kPa.

    (8) Determine the A, B, and C coefficients identified in Sec.
1066.210 as follows:
    (i) For chassis and post-transmission powerpack testing, follow the
procedures specified in Section 10 of SAE J1263 or Section 12 of SAE
J2263.
    (ii) For the GEM simulation tool, use the following values:

A = Am
B = 0
C = Dadj

Sec.  1066.320  Dynamometer road-load setting.

    Determine dynamometer road-load settings for chassis testing by
following SAE J2264 (incorporated by reference in Sec.  1066.1010).

Subpart E-- Preparing Vehicles and Running an Exhaust Emission Test

Sec.  1066.401  Overview.

    (a) Use the procedures detailed in this subpart to measure vehicle
emissions over a specified drive schedule. Different procedures may
apply for criteria pollutants and greenhouse gas emissions as described
in subpart I of this part or the standard-setting part. This subpart
describes how to:
    (1) Determine road-load power, test weight, and inertia class.
    (2) Prepare the vehicle, equipment, and measurement instruments for
an emission test.
    (3) Perform pre-test procedures to verify proper operation of
certain equipment and analyzers and to prepare them for testing.
    (4) Record pre-test data.
    (5) Sample emissions.
    (6) Record post-test data.
    (7) Perform post-test procedures to verify proper operation of
certain equipment and analyzers.
    (8) Weigh PM samples.
    (b) The overall test generally consists of prescribed sequences of
fueling, parking, and driving at specified test conditions. An exhaust
emission test generally consists of measuring emissions and other
parameters while a vehicle follows the drive schedules specified in the
standard-setting part. There are two general types of test cycles:
    (1) Transient cycles. Transient test cycles are typically specified
in the standard-setting part as a second-by-second sequence of vehicle
speed commands. Operate a vehicle over a transient cycle such that the
speed follows the target values. Proportionally sample emissions and
other parameters and use the calculations in 40 CFR part 1065, subpart
G, or subpart G of this part to calculate emissions. The standard-
setting part may specify three types of transient testing based on the
approach to starting the measurement, as follows:
    (i) A cold-start transient cycle where you start to measure
emissions just before starting an engine that has not been warmed up.
    (ii) A hot-start transient cycle where you start to measure
emissions just before starting a warmed-up engine.
    (iii) A hot running transient cycle where you start to measure
emissions after an engine is started, warmed up, and running.
    (2) Cruise cycles. Cruise test cycles are typically specified in
the standard-setting part as a discrete operating point that has a
single speed command.
    (i) Start a cruise cycle as a hot running test, where you start to
measure emissions after the engine is started and warmed up and the
vehicle is running at the target test speed.
    (ii) Sample emissions and other parameters for the cruise cycle in
the same manner as a transient cycle, with the exception that the
reference speed value is constant. Record instantaneous and mean speed
values over the cycle.

Sec.  1066.407  Vehicle preparation and preconditioning.

    Prepare the vehicle for testing (including measurement of
evaporative and refueling emissions, as required) as described in the
standard-setting part.

Sec.  1066.410  Dynamometer test procedure.

    (a) Dynamometer testing may consist of multiple drive cycles with
both cold-start and hot-start portions, including prescribed soak times
before each test interval. The standard-setting part identifies the
driving schedules and the associated sample intervals, soak periods,
engine startup and shutdown procedures, and operation of accessories,
as applicable. Not every test interval includes all these elements.
    (b) Place the vehicle onto the dynamometer without starting the
engine (for cold-start test cycles) or drive the vehicle onto
dynamometer (for hot-start and hot-running cycles only) and position a
fan that directs cooling air to the vehicle during dynamometer
operation as described in this paragraph (b). This generally requires
squarely positioning the fan in front of the vehicle and directing the
airflow to the vehicle's radiator. Use good engineering judgment to
design and configure fans to cool the test vehicle in a way that
properly simulates in-use operation, consistent with the specifications
of Sec.  1066.105. Except for the following special cases, use a road-
speed modulated fan meeting the requirements of Sec.  1066.105(c)(2) or
(d) that is placed within 90 cm of the front of the vehicle and ensure
that the engine compartment cover is closed:
    (1) For SC03 and AC17 testing, use a road-speed modulated fan
meeting the requirements of Sec.  1066.105(c)(3). Position the
discharge nozzle such that its lowest point is not more than 16 cm
above the floor of the test cell.
    (2) For FTP, LA-92, US06, or HFET testing of vehicles at or below
14,000 pounds GVWR, you may use a fixed-speed fan meeting the
requirements of Sec.  1066.105(c)(4) or (c)(5) as specified in the
following table, with the engine compartment cover open:

    Table 1 of Sec.   1066.410--Fixed-Speed Fan Capacity and Position
                             Specifications
------------------------------------------------------------------------
                                               Approximate distance from
    Test cycle        Maximum fan  capacity     the front of the vehicle
------------------------------------------------------------------------
FTP...............  Up to 2.50 m\3\/s........  0 to 30 cm
US06..............  2.50 m\3\/s to 7.10 m\3\/  0 to 60 cm
                     s.
LA-92.............  Up to 2.50 m\3\/s........  0 to 30 cm
HFET..............  Up to 2.50 m\3\/s........  0 to 30 cm
------------------------------------------------------------------------

    (c) Record the vehicle's speed trace based on the time and speed
data from the dynamometer. Record speed to at least the nearest 0.01
mph and time to at least the nearest 0.01 s.
    (d) You may perform practice runs for operating the vehicle and the
dynamometer controls to meet the driving tolerances specified in Sec.
1066.430 or adjust the emission sampling equipment. Verify that the
accelerator pedal allows for enough control to closely follow the
prescribed driving schedule. We recommend that you verify your ability
to meet the minimum dilution factor requirements of Sec.
1066.110(b)(2)(iii)(B) during these practice runs.
    (e) Inflate tires on drive wheels according to the vehicle
manufacturer's specifications. The tire pressure for drive wheels must
be the same for dynamometer operation and for dynamometer coastdown
procedures used for determining road-load

coefficients. Report these tire pressure values with the test results.
    (f) Tie down or load the test vehicle as needed to provide a normal
force at the tire and dynamometer roll interface to prevent wheel slip.
For vehicles above 14,000 pounds GVWR, report this force with the test
results.
    (g) For vehicles which provide four-wheel drive or all-wheel drive
operation, utilize the vehicle's normal (default) mode of operation.
(For purposes of this paragraph (g), the term four-wheel drive includes
other multiple drive axle configurations.) This may involve testing
four-wheel drive or all-wheel drive on a dynamometer with a separate
dynamometer roll for each drive axle. Alternatively, two drive axles
may use a single roll, as described in Sec.  1066.210(d)(1). You may
also test the vehicle on a single roll by deactivating the second set
of drive wheels, but only if this mode of operation does not decrease
emissions or energy consumption relative to normal in-use operation. We
may test such vehicles in four-wheel or all-wheel mode on one or more
rolls to confirm that the alternate dynamometer procedures did not
decrease emissions.
    (h) Determine test weight as follows:
    (1) For vehicles at or below 14,000 pounds GVWR, determine ETW as
described in Sec.  1066.810. Set dynamometer vehicle inertia, I, based
on dynamometer type, as follows:
    (i) For two-wheel drive dynamometers, set I = ETW.
    (ii) For four-wheel drive dynamometers, set I = 0.985[middot]ETW.
    (2) For vehicles above 14,000 pounds GVWR, determine the vehicle's
effective mass as described in 1066.310. This is the test weight.
    (i) Warm up the dynamometer as recommended by the dynamometer
manufacturer.
    (j) Following the test, determine the actual driving distance by
counting the number of dynamometer roll or shaft revolutions, or by
integrating speed over the course of testing from a high-resolution
encoder system.

Sec.  1066.420  Vehicle operation.

    This section describes how to test a conventionally configured
vehicle (vehicles with transmission shifters, foot pedal accelerators,
etc). You may ask us to modify these procedures for vehicles that do
not have these control features.
    (a) Start the vehicle as follows:
    (1) At the beginning of the test cycle, start the vehicle according
to the procedure described in the owners manual. In the case of hybrid
vehicles, this would generally involve activating vehicle systems such
that the engine will start when the vehicle's control algorithms
determine that the engine should provide power instead of or in
addition to power from the rechargeable energy storage system (RESS).
Unless we specify otherwise, engine starting throughout this part
generally refers to this step of activating the system on hybrid
vehicles, whether or not that causes the engine to start running.
    (2) Place the transmission in gear as described by the test cycle
in the standard-setting part. During idle operation, apply the brakes
if necessary to keep the drive wheels from turning.
    (b) If the vehicle does not start after your recommended maximum
cranking time, wait and restart cranking according to your recommended
practice. If you do not recommend such a cranking procedure, stop
cranking after 10 seconds, wait for 10 seconds, then start cranking
again for up to 10 seconds. You may repeat this for up to three start
attempts. If the vehicle does not start after three attempts, you must
determine and record the reason for failure to start. Shut off sampling
systems and either turn the CVS off or disconnect the exhaust tube from
the tailpipe during the diagnostic period to prevent flow through the
exhaust system. Reschedule the vehicle for testing. This may require
performing vehicle preparation and preconditioning if the testing needs
to be rerun from a cold start. If failure to start occurs during a hot-
start test, you may reschedule the hot-start test without repeating the
cold-start test, as long as you bring the vehicle to a hot-start
condition before starting the hot-start test.
    (c) Repeat the recommended starting procedure if the engine has a
false start (i.e., an incomplete start).
    (d) Take the following steps if the engine stalls:
    (1) If the engine stalls during an idle period, restart the engine
immediately and continue the test. If you cannot restart the engine
soon enough to allow the vehicle to follow the next acceleration, stop
the driving schedule indicator and reactivate it when the vehicle
restarts.
    (2) Void the test if the vehicle stalls during vehicle operation.
If this happens, remove the vehicle from the dynamometer, take
corrective action, and reschedule the vehicle for testing. Record the
reason for the malfunction (if determined) and any corrective action.
See the standard-setting part for instructions about reporting these
malfunctions.
    (e) Operate vehicles during testing as follows:
    (1) Where we do not give specific instructions, operate the vehicle
according to the recommendations in the owners manual, unless those
recommendations are unrepresentative of what may reasonably be expected
for in-use operation.
    (2) If vehicles have features that preclude dynamometer testing,
you may modify these features as necessary to allow testing, consistent
with good engineering judgment, as long as it does not affect your
ability to show that your vehicles comply with standards. Send us
written notification describing these changes along with supporting
rationale.
    (3) Operate vehicles during idle as follows:
    (i) For vehicles with automatic transmission, operate at idle with
the transmission in ``Drive'' with the wheels braked, except that you
may shift to ``Neutral'' for the first idle period and for any idle
period longer than one minute. If you put the vehicle in ``Neutral''
during an idle, you must shift the vehicle into ``Drive'' with the
wheels braked at least 5 seconds before the end of the idle period.
Note that this does not preclude vehicle designs involving engine
operation with stop-start functions where the engine stops when the
brake is applied below a certain threshold speed and restarts upon
release of the brake.
    (ii) For vehicles with manual transmission, operate at idle with
the transmission in gear with the clutch disengaged, except that you
may shift to ``Neutral'' with the clutch engaged for the first idle
period and for any idle period longer than one minute. If you put the
vehicle in ``Neutral'' during idle, you must shift to first gear with
the clutch disengaged at least 5 seconds before the end of the idle
period. Note that this does not preclude vehicle designs involving
engine operation with stop-start functions where the engine stops when
the clutch is disengaged below a certain threshold speed and restarts
upon reengagement of the clutch.
    (4) Operate the vehicle with the appropriate accelerator pedal
movement necessary to achieve the speed versus time relationship
prescribed by the driving schedule. Avoid smoothing speed variations
and excessive accelerator pedal perturbations.
    (5) Operate the vehicle smoothly, following representative shift
speeds and procedures. For manual transmissions, the operator shall
release the accelerator pedal during each shift and accomplish the
shift with minimum time. If the vehicle cannot accelerate at the
specified rate, operate it at

maximum available power until the vehicle speed reaches the value
prescribed for that time in the driving schedule.
    (6) Decelerate as follows:
    (i) For vehicles with automatic transmission, use the brakes or
accelerator pedal as necessary, without manually changing gears, to
maintain the desired speed.
    (ii) For vehicles with manual transmission, shift gears in a way
that represents reasonable shift patterns for in-use operation,
considering vehicle speed, engine speed, and any other relevant
variables. Disengage the clutch when the speed drops below 15 mph, when
engine roughness is evident, or when good engineering judgment
indicates the engine is likely to stall. Manufacturers may recommend
shift guidance in the owners manual that differs from the shift
schedule during testing as long as both shift schedules are included in
the application for certification. In this case, we may use the shift
schedule based on the shift pattern described in the owners manual.

Sec.  1066.425  Test preparation.

    (a) Follow the procedures for PM sample preconditioning and tare
weighing as described in 40 CFR 1065.590 if you need to measure PM
emissions.
    (b) For vehicles above 14,000 pounds GVWR with compression-ignition
engines, verify the amount of nonmethane hydrocarbon contamination as
described in 40 CFR 1065.520(g).
    (c) Unless the standard-setting part specifies different
tolerances, verify at some point before the test that ambient
conditions are within the tolerances specified in this paragraph (c).
For purposes of this paragraph (c), ``before the test'' means any time
from a point just prior to engine starting (excluding engine restarts)
to the point at which emission sampling begins.
    (1) Ambient temperature must be (20 to 30) [deg]C. See Sec.
1066.430(i) for circumstances under which ambient temperatures must
remain within this range during the test.
    (2) Dilution air conditions must meet the specifications in Sec.
1066.110(b)(2). We recommend verifying dilution air conditions just
before starting each test interval.
    (d) Control test cell ambient air humidity as follows:
    (1) For vehicles at or below 14,000 pounds GVWR, follow the
humidity requirements in Table 1 of this section, unless the standard-
setting part specifies otherwise. When complying with humidity
requirements in the table, where no tolerance is specified, use good
engineering judgment to maintain the humidity level near the specified
value within the limitations of your test facility.
    (2) For vehicles above 14,000 pounds GVWR, you may test vehicles at
any humidity.

                           Table 1 of Sec.   1066.425--Test Cell Humidity Requirements
----------------------------------------------------------------------------------------------------------------
                                              Humidity
                                             requirement
               Test cycle                  (grains H2O per        Tolerance  (grains H2O per pound dry air)
                                           pound dry air)
----------------------------------------------------------------------------------------------------------------
AC17....................................                69  5 average, > 10
                                                             instantaneous.
FTP\1\ and LA-92........................                50  ....................................................
HFET....................................                50  ....................................................
SC03....................................               100  5.
US06....................................                50  ....................................................
----------------------------------------------------------------------------------------------------------------
\1\ FTP humidity requirement does not apply for cold (-7 [deg]C), intermediate (10 [deg]C), and hot (35 [deg]C)
  temperature testing.

     (e) You may perform a final calibration of proportional-flow
control systems, which may include performing practice runs.
    (f) You may perform the following procedure to precondition
sampling systems:
    (1) Operate the vehicle over the test cycle.
    (2) Operate any dilution systems at their expected flow rates.
Prevent aqueous condensation in the dilution systems as described in 40
CFR 1065.140(c)(6), taking into account allowances given in Sec.
1066.110(b)(2)(iv).
    (3) Operate any PM sampling systems at their expected flow rates.
    (4) Sample PM using any sample media. You may change sample media
during preconditioning. You must 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.
    (g) 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, 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) Adjust the sample flow rates to desired levels using bypass
flow, if desired.
    (7) Zero or re-zero any electronic integrating devices before the
start of any test interval.
    (8) Select gas analyzer ranges. You may not switch the gain of an
analyzer's analog operational amplifier(s) during a test. However, you
may switch (automatically or manually) gas analyzer ranges during a
test if such switching changes only the range over which the digital
resolution of the instrument is applied.
    (9) Zero and span all continuous gas analyzers using gases that
meet the specifications of 40 CFR 1065.750. For FID analyzers, you may
account for the carbon number of your span gas either during the
calibration process or when calculating your final emission value. For
example, if you use a C3H8 span gas of
concentration 200 ppm ([mu]mol/mol), you may span the FID to respond
with a value of 600 ppm ([mu]mol/mol) of carbon or 200 ppm of propane.
However, if your FID response is equivalent to propane, include a
factor of three to make the final calculated hydrocarbon mass
consistent with a molar mass of 13.875389. When utilizing an NMC-FID,
span the FID analyzer consistent with the determination of their
respective response factors, RF, and penetration

fractions, PF, according to 40 CFR 1065.365.
    (10) 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, use good engineering judgment to decide whether or not to re-
zero, re-span, or re-calibrate a gas analyzer before starting a test.
    (11) If you correct for dilution air background concentrations of
associated engine exhaust constituents, start sampling and recording
background concentrations at the same time you start sampling exhaust
gases.
    (12) Turn on cooling fans immediately before starting the test.
    (h) Proceed with the test sequence described in Sec.  1066.430.

Sec.  1066.430  Performing emission tests.

    (a) See the standard-setting part for drive schedules. These are
defined by a smooth fit of a specified speed vs. time sequence.
    (b) The driver must attempt to follow the target schedule as
closely as possible, consistent with the specifications in paragraph
(b) of this section. Instantaneous speeds must stay within the
following tolerances:
    (1) The upper limit is 2.0 mph higher than the highest point on the
trace within 1.0 s of the given point in time.
    (2) The lower limit is 2.0 mph lower than the lowest point on the
trace within 1.0 s of the given time.
    (3) The same limits apply for vehicle operation without exhaust
measurements, such as vehicle preconditioning and warm-up, except that
the upper and lower limits for speed values are 4.0 mph. In
addition, up to three occurrences of speed variations greater than the
tolerance are acceptable for vehicle operation without exhaust
measurements, as long as they occur for less than 15 seconds on any
occasion and are clearly documented as to the time and speed at that
point of the driving schedule.
    (4) Void the test if you do not maintain speed values as specified
in this paragraph (b), except as allowed by this paragraph (b)(4).
Speed variations (such as may occur during gear changes or braking
spikes) may occur as follows, provided that such variations are clearly
documented, including the time and speed values and the reason for the
deviation:
    (i) Speed variations greater than the specified limits are
acceptable for up to 2.0 seconds on any occasion.
    (ii) For vehicles that are not able to maintain acceleration as
specified in Sec.  1066.420(e)(5), do not count the insufficient
acceleration as being outside the specified limits.
    (5) We may approve an alternate test cycle and cycle-validation
criteria for vehicles that do not have enough power to follow the
specified driving trace. The alternate driving specifications must be
based on making best efforts to maintain acceleration and speed to
follow the specified test cycle. We must approve these alternate
driving specifications before you perform this testing.
    (c) Figure 1 and Figure 2 of this section show the range of
acceptable speed tolerances for typical points during testing. Figure 1
of this section is typical of portions of the speed curve that are
increasing or decreasing throughout the 2-second time interval. Figure
2 of this section is typical of portions of the speed curve that
include a maximum or minimum value.

[GRAPHIC] [TIFF OMITTED] TP21MY13.070

    (d) Start testing as follows:
    (1) If a vehicle is already running and warmed up, and starting is
not part of the test cycle, operate the vehicle as follows:
    (i) For transient test cycles, control vehicle speeds to follow a
drive schedule consisting of a series of idles, accelerations, cruises,
and decelerations.
    (ii) For cruise test cycles, control the vehicle operation to match
the speed of the first interval of the test cycle. Follow the
instructions in the standard-setting part to determine how long to
stabilize the vehicle during each interval, how long to sample
emissions at each interval, and how to transition between intervals.
    (2) If engine starting is part of the test cycle, start recording
continuous data,

any electronic integrating devices, and batch sampling before starting
the engine. Initiate the driver's trace when the engine starts.
    (e) Perform the following at the end of each test interval, except
as specified in subpart I of this part:
    (1) Shut down the vehicle if it is part of the test cycle or if
testing is complete.
    (2) Continue to operate all sampling and dilution systems to allow
the response times to elapse. Then stop all sampling and recording,
including background sampling. Finally, stop any integrating devices
and indicate the end of the duty cycle in the recorded data.
    (f) If testing involves engine shutdown followed by another test
interval, start a timer for the vehicle soak when the engine shuts
down. Turn off cooling fans, close the vehicle hood (if applicable),
and turn off the CVS or disconnect the exhaust tube from the
tailpipe(s) of the vehicle unless otherwise instructed in the standard-
setting part. If testing is complete, disconnect the exhaust tube from
the vehicle tailpipe(s) and drive the vehicle from dynamometer.
    (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
40 CFR 1065.545. Void any samples that did not maintain proportional
sampling according to those specifications.
    (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 40 CFR 1065.595.
    (3) As soon as practical after the interval or test cycle is
complete, or optionally during the soak period if practical, perform
the following:
    (i) Begin drift check for all continuous gas analyzers as described
in paragraph (g)(6) of this section and zero and span all batch gas
analyzers as soon as practical prior to any batch sample analysis. You
may perform this batch analyzer zero and span prior to the end of the
test cycle or interval.
    (ii) Analyze any conventional gaseous batch samples (HC,
CH4, CO, NOX, and CO2) no later than
30 minutes after an interval or test cycle is complete, or during the
soak period if practical. Analyze background samples no later than 60
minutes after the test cycle is complete.
    (iii) Analyze nonconventional gaseous batch samples (including
background), such as NMHCE, N2O, or NMOG sampling with
ethanol, as soon as practicable using good engineering judgment.
    (4) Range validation. If an analyzer operated above 100% of its
range at any time during the test, perform the following steps:
    (i) 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.
    (ii) 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 consistently operates at less than 100% of
its range. Keep records of any tests where the analyzer exceeds its
range. We may consider these results to be failures, consistent with
good engineering judgment.
    (5) After quantifying exhaust gases, verify drift as follows:
    (i) For batch and continuous gas analyzers, 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 that analyzer drift does not
exceed 2.0% of the analyzer full scale.
    (h) [Reserved]
    (i) Measure and record ambient pressure. Measure and record ambient
temperature continuously to verify that it remains within the
temperature range specified in Sec.  1066.425(c)(1) throughout the
test. Also measure humidity if required, such as for correcting
NOX emissions, or meeting the requirements of Sec.
1066.425(d).
    (j) For vehicles at or below 14,000 pounds GVWR, determine overall
driver accuracy as follows:
    (1) Compare the following drive cycle metrics, based on measured
vehicle speeds, to a reference value based on the target cycle that
would have been generated by driving exactly to the target trace as
described in SAE J2951 (incorporated by reference in Sec.  1066.1010).
    (i) Determine the Energy Economy Rating as described in Section 5.4
of SAE J2951.
    (ii) Determine the Absolute Speed Change Rating as described in
Section 6.1.2 of SAE J2951.
    (iii) Calculate the Inertia Work Rating, IR, using the both the
sums of the incremental driven and the target inertia work as described
in Eq. 1066.430-1.
[GRAPHIC] [TIFF OMITTED] TP21MY13.072

Where:

FIDi = the driven inertial force over an interval i, as
described by Equation 18 of SAE J2951.
FIDj = the target inertial force over an interval j, as
described by Equation 19 of SAE J2951.
DDi = the incremental driven distance over an interval i,
as described by Equation 12 of SAE J2951.
DDj = the incremental target distance over an interval j,
as described by Equation 13 of SAE J2951.

    (2) The standard-setting part may require you to provide to us 10
Hz data to characterize both target and actual values for cycle energy.
Calculate target values based on the vehicles speeds from the specified
test cycle.

Subpart F--Hybrids and Electric Vehicles

Sec.  1066.501  Overview.

    For HEV, PHEV, and pure electric vehicle (EV), use the following
procedures:
    (a) Correct the results for Net Energy Change of the RESS as
follows:
    (1) For vehicles at or below 14,000 pounds GVWR, follow SAE J1711
(incorporated by reference in Sec.  1066.1010) except as noted in this
paragraph (a). Use 1% of reading or 0.3% of
full scale, whichever is greater, in place of the current measurement
accuracy in Section 4.2a of SAE J1711.
    (2) For vehicles above 14,000 pounds GVWR, follow SAE J2711
(incorporated by reference in Sec.  1066.1010) for requirements related
to charge-sustaining operation.
    (3) For pure EVs, irrespective of GVWR, follow SAE J1634
(incorporated by reference in Sec.  1066.1010).
    (b) This paragraph (b) applies for vehicles that include an engine-
powered generator or other auxiliary power unit that provides motive
power. For example, this would include a vehicle that has a small
gasoline engine that generates electricity to charge batteries. Unless
we approve otherwise, measure emissions for all test cycles when such
an engine is operating. For each test cycle for which emissions are not
measured, you must validate that such engines are not operating at any
time during the test cycle.

Subpart G--Calculations

Sec.  1066.601  Overview.

    (a) This subpart describes calculations used to determine emission
rates. See the standard setting part and the other provisions of this
part to determine which equations apply for your testing. This subpart
describes how to--
    (1) Use the signals recorded before, during, and after an emission
test to calculate distance-specific emissions of each regulated
pollutant.
    (2) Perform calculations for calibrations and performance checks.
    (3) Determine statistical values.
    (b) You may use data from multiple systems to calculate test
results for a single emission test, consistent with good engineering
judgment. You may also make multiple measurements from a single batch
sample, such as multiple weighing of a PM filter or multiple readings
from a bag sample. Although you may use an average of multiple
measurements from a single test, you may not use test results from
multiple emission tests to report emissions. We allow weighted means
where appropriate, such as for sampling onto a PM filter over the FTP.
You may discard statistical outliers, but you must report all results.

Sec.  1066.610  Mass-based and molar-based exhaust emission
calculations.

    (a) Calculate your total mass of emissions over a test cycle as
specified in paragraph (c) of this section or in 40 CFR part 1065,
subpart G, as applicable.
    (b) For composite emission calculations over multiple test
intervals and corresponding weighting factors, see the standard-setting
part.
    (c) To calculate total mass emissions, multiply a concentration by
its respective flow and density as specified in Eq. 1066.610-1. Before
calculating mass emissions as specified in paragraph (d) and (e) of
this section, perform the following sequence of preliminary
calculations to correct recorded concentration measurements:
    (1) For vehicles above 14,000 pounds GVWR, correct all THC and
CH4 concentrations for initial contamination as described in
40 CFR 1065.660(a), including continuous readings, sample bag readings,
and dilution air background readings. This correction is optional for
vehicles at or below 14,000 pounds GVWR.
    (2) Correct all concentrations measured on a ``dry'' basis to a
``wet'' basis, including dilution air background concentrations.
    (3) Calculate all NMHC and CH4 concentrations, including
dilution air background concentrations, as described in 40 CFR
1065.660.
    (4) For vehicles at or below 14,000 pounds GVWR, calculate HC
concentrations, including dilution air background concentrations, as
described in this section and Sec.  1066.665 for NMOG. For emission
testing of vehicles above 14,000 pounds GVWR, with fuels that contain
25% or more oxygenated compounds by volume, calculate HC
concentrations, including dilution air background concentrations, as
described in 40 CFR part 1065, subpart I, for THCE and NMHCE.
    (5) Correct all NOX emission values for test cell
ambient air humidity as described in Sec.  1066.630.
    (6) Correct all gaseous concentrations for dilution air background
as described in Sec.  1066.620.
    (7) Correct all PM filter masses for sample media buoyancy as
described in 40 CFR 1065.690.
    (d) Calculate the emission mass of each gaseous pollutant using the
following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.073

    Where:
    m[emission] = emission mass over the test interval.
Vmix = total dilute exhaust volume over the test interval
at standard reference conditions, corrected for any volume removed
for emission sampling and the addition of secondary dilution air (if
applicable).
[rho][emission] = density of the appropriate chemical
species as given in Sec.  1066.1005(f).
[khgr][emission] = measured emission concentration in the
sample, after dry-to-wet and background corrections.
c = 10-\2\ for emission concentrations % and 10\-6\ for
emission concentrations in ppm.

Example:

Vmix = 170.878 m\3\ (from paragraph (f) of this section)
[rho]NOx = 1913 g/m\3\
[khgr]NOx = 0.9721 ppm
c = 10-\6\
mNOx =
170.878[middot]1913[middot]0.9721[middot]10-\6\ = 0.3177 g

    (e) The calculation of PM is dependent on how many PM filters are
used (for example as described in Sec.  1066.822(b)), as follows:
    (1) Except as specified in paragraphs (e)(2) and (3) of this
section, calculate mPM using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.074

Where:
mPM = mass of particulate matter emissions over the test
interval, as described in Sec.  1066.820(b)(1), (2), and (3).
Vmix = total dilute exhaust volume over the test interval
at standard reference conditions, corrected for any volume removed
for emissions sampling and the addition of secondary dilution air
(if applicable).
Vsdastd = total volume of secondary dilution air flow
sampled through the filter over the test phase at standard
temperature and pressure.
mPMfil = mass of particulate matter emissions on the
filter over the test interval.
mPMbkgnd = mass of particulate matter on the background
filter.

Example:

Vmix = 170.878 m\3\ (from paragraph (f) of this section)
VPMstd = 0.925 m\3\ (from paragraph (f) of this section)
Vsdastd = 0.527 m\3\ (from paragraph (f) of this section)
mPMfil = 0.0000045 g
mPMbkgnd = 0.0000014 g
[GRAPHIC] [TIFF OMITTED] TP21MY13.075

    (2) If you sample PM onto a single filter as described in Sec.
1066.820(b)(4), calculate mPM using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.076

Eq. 1066.610-3

Where:

mPM = mass of particulate matter emissions over the
entire FTP as sampled according to Sec.  1066.820(b)(4).
Vmix = total dilute exhaust volume over the test interval
at standard reference conditions, corrected for any volume removed
for emissions sampling and the addition of secondary dilution air
(if applicable).
V[interval]-PMstd = total volume of dilute exhaust
sampled through the filter over the test interval (ct = cold
transient, s = stabilized, ht = hot transient) at standard reference
conditions.
V[interval]-sdastd = total volume of secondary dilution
air sampled through the filter over the test interval (ct = cold
transient, s = stabilized, ht = hot transient) at standard reference
conditions.
mPMfil = mass of particulate matter emissions on the
filter over the test interval.
mPMbkgnd = mass of particulate matter on the background
filter.

Example:

Vmix = 633.691 m\3\
Vct-PMstd = 0.925 m\3\
Vct-sdastd = 0.527 m\3\
Vs-PMstd = 1.967 m\3\
Vs-sdastd = 1.121 m\3\
Vht-PMstd = 1.122 m\3\
Vht-sdastd = 0.639 m\3\
mPMfil = 0.0000106 g
mPMbkgnd = 0.0000014 g
[GRAPHIC] [TIFF OMITTED] TP21MY13.077

mpm = 0.00222 g
    (3) If you sample PM onto a single filter as described in Sec.
1066.820(b)(5), calculate mPM using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.078

Where:

mPM = mass of particulate matter emissions over the
entire FTP as sampled according to Sec.  1066.820(b)(5).
Vmix = total dilute exhaust volume over the test interval
at standard reference conditions, corrected for any volume removed
for emissions sampling and the addition of secondary dilution air
(if applicable).
V[interval]-PMstd = total volume of dilute exhaust
sampled through the filter over the test interval (ct = cold
transient, cs = cold stabilized, ht = hot transient, hs = hot
stabilized) at standard reference conditions.
V[interval]-sdastd = total volume of secondary dilution
air sampled through the filter over the test interval (ct = cold
transient, cs = cold stabilized, ht = hot transient, hs = hot
stabilized) at standard reference conditions.
mPMfil = mass of particulate matter emissions on the
filter over the test interval.
mPMbkgnd = mass of particulate matter on the background
filter.

Example:

Vmix = 972.121 m\3\
Vct-PMstd = 0.925 m\3\
Vct-sdastd = 0.529 m\3\
Vcs-PMstd = 1.968 m\3\
Vcs-sdastd = 1.123 m\3\
Vht-PMstd = 1.122 m\3\
Vht-sdastd = 0.641 m\3\
Vhs-PMstd = 1.967 m\3\
Vhs-sdastd = 1.121 m\3\
mPMfil = 0.0000229 g
mPMbkgnd = 0.0000014 g
[GRAPHIC] [TIFF OMITTED] TP21MY13.079

MPM = 0.00155 g

    (f) This paragraph (f) describes how to correct flow and flow rates
to standard reference conditions and provides an example for
determining Vmix based on CVS total flow and the removal of
sample flow from the dilute exhaust gas.
    (1) Correct flow and flow rates to standard reference conditions as
needed using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.080

Where:

V[flow]std = total volume of flow at the flow meter at
standard reference conditions.
V[flow]act = total volume of flow at the flow meter at
test conditions.
pin = absolute static pressure at the flow meter inlet,
measured directly or calculated as the sum of atmospheric pressure
plus a differential pressure referenced to atmospheric pressure.
Tstd = standard temperature.
pstd = standard pressure.
Tin = average temperature of the dilute exhaust sample at
the flow meter inlet.

Example:

VPMact = 1.071 m\3\
pin = 101.7 kPa
Tstd = 293.15 K
pstd = 101.325 kPa
Tin = 340.5 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.081

    (2) The following example provides a determination of
Vmix based on CVS total flow and the removal of sample flow
from one dilute exhaust gas analyzer and one PM sampling system that is
utilizing secondary dilution. Note that your Vmix
determination may vary from Eq. 1066.610-6 based on the number of flows
that are removed from your dilute exhaust gas and whether your PM
sampling system is using secondary dilution. For this example,
Vmix is governed by the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.082

Where:

VCVSstd = total dilute exhaust volume over the test
interval at the flow meter at standard reference conditions.
Vgasstd = total volume of sample flow through the gaseous
emission bench over the test interval at standard reference
conditions.
VPMstd = total volume of dilute exhaust sampled through
the filter over the test interval at standard reference conditions.
Vsdastd = total volume of secondary dilution air flow
sampled through the filter over the test interval at standard
reference conditions.

Example:

    Using Eq. 1066.610-5

VCVSstd = 170.451 m\3\, where VCVSact = 170.721
m\3\, pin = 101.7 kPa, and Tin = 294.7 K

    Using Eq. 1066.610-5

Vgasstd = 0.028 m\3\, where Vgasact = 0.033 m\3\,
pin = 101.7 kPa, and Tin = 340.5 K

    Using Eq. 1066.610-5

VPMstd = 0.925 m\3\, where VPMact = 1.071 m\3\,
pin = 101.7 kPa, and Tin = 340.5 K

    Using Eq. 1066.610-5

Vsdastd = 0.527 m\3\, where Vsdaact = 0.531 m\3\,
pin = 101.7 kPa, and Tin = 296.3 K
Vmix = 170.451 + 0.028 + 0.925 - 0.527 = 170.878 m\3\

    (g) Total sample volume over a test interval. Calculate total flow,
V[flow], for a CVS or exhaust gas sampler as follows:
    (1) Varying versus constant flow rates. The calculation methods
depend on differentiating varying and constant flow, as follows:
    (i) We consider the following to be examples of varying flows that
require a continuous multiplication of concentration times volumetric
flow rate: raw exhaust, exhaust diluted with a constant flow rate of
dilution air, and CVS dilution with a CVS flow meter that does not have
an upstream heat exchanger or electronic flow control.
    (ii) We consider the following to be examples of constant exhaust
flows: CVS diluted exhaust with a CVS flow meter that has an upstream
heat exchanger, an electronic flow control, or both.
    (2) Continuous sampling. For continuous sampling, you must
frequently record a continuously updated flow signal. This recording
requirement applies for both varying and constant flow rates.
    (i) Varying flow rate. If you continuously sample from a varying
exhaust flow rate, calculate V[flow] using the following
equation:

[GRAPHIC] [TIFF OMITTED] TP21MY13.083

Where:
[GRAPHIC] [TIFF OMITTED] TP21MY13.138

Example:

N = 505
QCVS1 = 0.276 m\3\/s
QCVS2 = 0.294 m\3\/s
[fnof]record = 1 Hz

    Using Eq. 1066.610-8,

[Delta]t = 1/1 = 1 s
VCVS = (0.276+0.294+...+QQCVS505) [middot] 1
VCVS = 170.721 m\3\

    (ii) Constant flow rate. If you continuously sample from a constant
exhaust flow rate, use the same calculation described in paragraph
(g)(2)(i) of this section or calculate the mean flow recorded over the
test interval and treat the mean as a batch sample, as described in
paragraph (g)(3)(ii) of this section.
    (3) Batch sampling. For batch sampling, calculate total flow by
integrating a varying flow rate or by determining the mean of a
constant flow rate, as follows:
    (i) Varying flow rate. If you proportionally collect a batch sample
from a varying exhaust flow rate, integrate the flow rate over the test
interval to determine the total flow from which you extracted the
proportional sample, as described in paragraph (g)(2)(i) of this
section.
    (ii) Constant flow rate. If you batch sample from a constant
exhaust flow rate, extract a sample at a proportional or constant flow
rate and calculate V[flow] from the flow from which you
extract the sample by multiplying the mean flow rate by the time of the
test interval using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.084

    Example:

QCVS = 0.338 m\3\/s
[Delta]t = 505 s
VCVS = 0.338 [middot] 505
VCVS = 170.69 m\3\

Sec.  1066.620  Dilution air background correction.

    (a) Correct the emissions in a gaseous sample for background using
the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.139

Where:

[khgr][emission]dexh = measured emission concentration in
dilute exhaust (after dry-to-wet correction for dry measurements).
[khgr][emission]bkgnd = measured emission concentration
in the dilution air (after dry-to-wet correction for dry
measurements).
DF = dilution factor determined in paragraph (b) of this section.

Example:

[khgr]NOxdexh = 1.08305 ppm
[khgr]NOxbkgnd = 0.12456 ppm
DF = 9.14506
[GRAPHIC] [TIFF OMITTED] TP21MY13.085

    (b) Determine the dilution factor, DF, over the test interval using
the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.086

Where:

[khgr]CO2 = amount of CO2 measured in the
sample over the test interval.
[khgr]NMHC = amount of C1-equivalent NMHC
measured in the sample over the test interval.
[khgr]CH4 = amount of CH4 measured in the
sample over the test interval.
[khgr]CO = amount of CO measured in the sample over the
test interval.
[alpha] = atomic hydrogen-to-carbon ratio of the test. You may
measure [alpha] or use default values from Table 1 of 40 CFR
1065.655.
[beta] = atomic oxygen-to-carbon ratio of the test fuel. You may
measure [beta] or use default values from Table 1 of 40 CFR
1065.655.

Example:

[khgr]CO2 = 1.456% = 0.01456
[khgr]NMHC = 0.84 ppm = 0.00000084
[khgr]CH4 = 0.26 ppm = 0.00000026
[khgr]CO = 80.4 ppm = 0.0000804
[alpha] = 1.92
[beta] = 0.03

[GRAPHIC] [TIFF OMITTED] TP21MY13.087

    (c) Determine the dilution factor, DF, over the test interval for
partial-flow dilution sample systems that measure PM using the
following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.088

Where:

VPMstd = total dilute exhaust volume sampled through the
filter over the test interval at standard reference conditions.
Vexhstd = total exhaust volume sampled from the vehicle
at standard reference conditions.

Example:

VPMstd = 170.9 m\3\
Vexhstd = 15.9 m\3\
[GRAPHIC] [TIFF OMITTED] TP21MY13.089

    (d) Determine the time-weighted dilution factor, DFw,
over the duty cycle using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.090

Where:

N = number of test intervals.
i = test interval number
t = duration of the test interval.
DF = dilution factor over the test interval.

Example:

N = 3
DF1 = 14.40
t1 = 505 s
DF2 = 24.48
t2 = 867 s
DF3 = 17.28
t3 = 505 s
[GRAPHIC] [TIFF OMITTED] TP21MY13.091

Sec.  1066.630  NOX intake-air humidity correction.

    See the standard-setting part to determine if you may correct
NOX emissions for the effects of intake-air humidity.
Correct NOX emissions for intake-air humidity as described
in this section. See Sec.  1066.610(c)(1) for the proper sequence for
applying the NOX intake-air humidity correction.
    (a) For vehicles at or below 14,000 pounds GVWR, apply a correction
for any reciprocating engines for the following test cycles:
    (1) Calculate a humidity correction using a time-weighted mean
value for ambient humidity over the test interval. Calculate absolute
ambient humidity in grams H2O vapor per kilogram of dry air
using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.092

Where:

MH2O = molar mass of H2O, in g/mol.
pd = saturated vapor pressure at the ambient dry bulb
temperature, in kPa.
RH% = relative humidity of ambient air, in %.
Mair = molar mass of air, in g/mol.
patmos = atmospheric pressure, in kPa.

    Example:
MH2O = 18.01528 g/mol
pd = 2.93 kPa
RH % = 37.5%
Mair = 28.96559 g/mol
patmos = 96.71 kPa
[GRAPHIC] [TIFF OMITTED] TP21MY13.093

    (2) Use the following equation to correct measured concentrations
to a reference condition of 10.71 grams H2O vapor per
kilogram of dry air for the FTP, US06, LA-92, SC03, and HFET test
cycles:

[GRAPHIC] [TIFF OMITTED] TP21MY13.094

Where:

[khgr]NOxdexh = measured dilute NOX emissions.
Hs = humidity scale. Set = 1 for FTP, US06, LA-92, and
HFET test cycles. Set = 0.8825 for the SC03 test cycle.
H = absolute humidity, from paragraph (a)(1) of this section.

    Example:
H = 7.14741 g H2O vapor/kg dry air
[khgr]NOxdexh = 1.21 ppm
[GRAPHIC] [TIFF OMITTED] TP21MY13.095

    (b) For vehicles above 14,000 pounds GVWR, apply correction factors
as described in 40 CFR 1065.670.

Sec.  1066.640  Removed water correction.

    Correct for removed water if water removal occurs upstream of a
concentration measurement and downstream of a flow meter used to
determine mass emissions over a test interval. Perform this correction
based on the amount of water at the concentration measurement and on
the amount of water at the flow meter.

Sec.  1066.650  Flow meter calibration calculations.

    This section describes how to calibrate various flow meters based
on mass flow rates. Calibrate your flow meter according to 40 CFR
1065.640 instead if you calculate emissions based on molar flow rates.
    (a) PDP calibration calculations. Perform the following steps to
calibrate a PDP flow meter:
    (1) Calculate PDP volume pumped per revolution, Vrev,
for each restrictor position from the mean values determined in Sec.
1066.140:
[GRAPHIC] [TIFF OMITTED] TP21MY13.096

Where:

Qref = mean flow rate of the reference flow meter.
Tin = mean temperature at the PDP inlet.
Pstd = standard pressure = 101.325 kPa.
fnPDP = mean PDP speed.
pin = mean static absolute pressure at the PDP inlet.
Tstd = standard temperature = 293.15 K.

    Example:
Qref = 0.1651 m\3\/s
Tin = 299.5 K
pstd = 101.325 kPa

fnPDP = 1205.1 r/min = 20.085 r/s
pin = 98.290 kPa
Tstd = 293.15 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.097

Vrev = 0.00866 m\3\/r
    (2) Calculate a PDP slip correction factor, Ks for each
restrictor position from the mean values determined in Sec.  1066.140:
[GRAPHIC] [TIFF OMITTED] TP21MY13.098

Where:

fnPDP = mean PDP speed.
pout = mean static absolute pressure at the PDP outlet.
pin = mean static absolute pressure at the PDP inlet.

    Example:
fnPDP = 1205.1 r/min = 20.085 r/s
pout = 100.103 kPa
pin = 98.290 kPa
[GRAPHIC] [TIFF OMITTED] TP21MY13.099

Ks = 0.006700 s/r

    (3) Perform a least-squares regression of Vrev, versus
PDP Ks, by calculating slope, a1, and intercept,
a0, as described in 40 CFR 1065.602.
    (4) Repeat the procedure in paragraphs (a)(1) through (3) of this
section for every speed that you run your PDP.
    (5) The following example illustrates a range of typical values for
different PDP speeds:

       Table 1 of Sec.   1066.650--Example of PDP Calibration Data
------------------------------------------------------------------------
                 f8nPDP (r/s)                   a1 (m\3\/s)  a0 (m\3\/r)
------------------------------------------------------------------------
12.6..........................................        0.841        0.056
16.5..........................................        0.831       -0.013
20.9..........................................        0.809        0.028
23.4..........................................        0.788       -0.061
------------------------------------------------------------------------

    (6) For each speed at which you operate the PDP, use the
appropriate regression equation from this paragraph (a) to calculate
flow rate during emission testing as described in Sec.  1066.652.
    (b) SSV calibration. The equations governing SSV flow assume one-
dimensional isentropic inviscid flow of an ideal gas, except that the
equations can account for compressible flow. Paragraph (b)(2)(iv) of
this section describes other assumptions that may apply. If good
engineering judgment dictates that you account for gas compressibility,
you may either use an appropriate equation of state to determine values
of Z as a function of measured pressure and temperature, or you may
develop your own calibration equations based on good engineering
judgment. Note that the equation for the flow coefficient,
Cf, is based on the ideal gas assumption that the isentropic
exponent, [gamma], is equal to the ratio of specific heats,
Cp/Cv. If good engineering judgment dictates
using a real gas isentropic exponent, you may either use an appropriate
equation of state to determine values of [gamma] as a function of
measured pressure and temperature, or you may develop your own
calibration equations based on good engineering judgment.
    (1) Calculate volumetric flow rate, Q, as follows:

[GRAPHIC] [TIFF OMITTED] TP21MY13.100

Where:

Cd = discharge coefficient, as determined in paragraph
(b)(2)(i) of this section.
Cf = flow coefficient, as determined in paragraph
(b)(2)(ii) of this section.
At = cross-sectional area at the venturi throat.
R = molar gas constant.
pin = static absolute pressure at the venturi inlet.
Tstd = standard temperature.
pstd = standard pressure.
Z = compressibility factor.
Mmix = molar mass of gas mixture.
Tin = absolute temperature at the venturi inlet.

    (2) Perform the following steps to calibrate an SSV flow meter:
    (i) Using the data collected in Sec.  1066.140, calculate
Cd for each flow rate using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.101

Where:

Qref = measured volumetric flow rate from the reference
flow meter.

    (ii) Use the following equation to calculate Cf for each
flow rate:
[GRAPHIC] [TIFF OMITTED] TP21MY13.102

Where:

[gamma] = isentropic exponent. For an ideal gas, this is the ratio
of specific heats of the gas mixture, Cp/Cv.
r = pressure ratio, as determined in paragraph (b)(2)(iii) of this
section.
[beta] = ratio of venturi throat diameter to inlet diameter.

    (iii) Calculate r using the following equation:
    [GRAPHIC] [TIFF OMITTED] TP21MY13.103

Where:

    [Delta]p = differential static pressure, calculated as venturi
inlet pressure minus venturi throat pressure.

    (iv) You may apply any of the following simplifying assumptions or
develop other values as appropriate for your test configuration,
consistent with good engineering judgment:
    (A) For raw exhaust, diluted exhaust, and dilution air, you may
assume that the gas mixture is incompressible and therefore behaves as
an ideal gas (Z = 1).
    (B) For raw exhaust, you may assume [ballot] = 1.385.
    (C) For diluted exhaust and dilution air, you may assume [ballot] =
1.399.
    (D) For diluted exhaust and dilution air, you may assume
Mmix is a function only of the amount of water in the
dilution air or calibration air, xH2O, as follows:
[GRAPHIC] [TIFF OMITTED] TP21MY13.104

    Where:

Mair = 28.964 g/mol
xH2O = amount of H2O in the dilution air,
determined as described in 40 CFR 1065.645.
MH20 = 18.015 g/mol

Example:
xH2O = 0.0169 mol/mol
Mmix =28.964[middot](1 - 0169) + 18.015[middot]0.0169
Mmix = 28.7789 g/mol

    (E) For diluted exhaust and dilution air, you may assume a constant
molar mass of the mixture, Mmix, for all calibration and all
testing if you control the amount of water in calibration air and in
dilution air, as shown in the following table:

Table 2 of Sec.   1066.650--Examples of Dilution Air and Calibration Air
           Dewpoints at Which you May Assume a Constant Mmix.
------------------------------------------------------------------------
                                                              for the
                                                             following
                                            assume the    ranges of Tdew
  If calibration Tdew ([deg]C) is . . .      following       ([deg]C)
                                           constant Mmix      during
                                           (g/mol) . . .     emission
                                                             tests\a\
------------------------------------------------------------------------
<= 0....................................        28.96559           <= 18
0.......................................        28.89263           <= 21
5.......................................        28.86148           <= 22
10......................................        28.81911           <= 24
15......................................        28.76224           <= 26
20......................................        28.68685        -8 to 28
25......................................        28.58806        12 to 31
30......................................        28.46005        23 to 34
------------------------------------------------------------------------
\a\ The specified ranges are valid for all calibration and emission
  testing over the atmospheric pressure range (80.000 to 103.325) kPa.

    (v) The following example illustrates the use of the governing
equations to calculate Cd of an SSV flow meter at one
reference flow meter value:

Example:
Q = 2.395 m\3\/s
Z = 1
Mmix = 28.7789 g/mol = 0.0287789 kg/mol
R = 8.314472 J/(mol[sdot]K) = 8.314472 (m\2\[sdot]kg)/
(s\2\[sdot]mol[sdot]K)
Tin = 298.15 K
At = 0.01824 m\2\
pin = 99.132 kPa = 99132 Pa = 99132 kg/(m[sdot]s\2\)
[gamma] = 1.399
[beta] = 0.8
[Delta]p = 2.312 kPa
[Delta]p = 2.312 kPa

[GRAPHIC] [TIFF OMITTED] TP21MY13.105

Cf = 0.274
[GRAPHIC] [TIFF OMITTED] TP21MY13.106

Cd = 1.695
    (vi) Calculate the Reynolds number, Re#, for each reference
volumetric flow rate Q \ref\, using the throat diameter of the venturi,
dt, and the uncorrected air density, [rho]. Because the
dynamic viscosity, [mu], is needed to compute Re#, you may use your own
fluid viscosity model to determine [mu] for your calibration gas
(usually air), using good engineering judgment. Alternatively, you may
use the Sutherland three-coefficient viscosity model to approximate
[mu], as shown in the following sample calculation for Re #:
[GRAPHIC] [TIFF OMITTED] TP21MY13.107

    Where, using the Sutherland three-coefficient viscosity model:
    [GRAPHIC] [TIFF OMITTED] TP21MY13.108

    Where:

[mu]0 = Sutherland reference viscosity.
T0 = Sutherland reference temperature.
S = Sutherland constant.

               Table 3 of Sec.   1065.640--Sutherland Three-Coefficient Viscosity Model Parameters
----------------------------------------------------------------------------------------------------------------
                                                                                Temp range
                                                                                within
               Gas\a\                         [mu]0                T0           S          2%    limit \b\
                                                                                error \b\
                                               kg/(m[sdot]s)            K            K            K          kPa
----------------------------------------------------------------------------------------------------------------
Air................................        1.716[sdot]10-\5\          273          111  170 to 1900      <= 1800
CO2................................        1.370[sdot]10-\5\          273          222  190 to 1700      <= 3600
H2O................................         1.12[sdot]10-\5\          350         1064  360 to 1500     <= 10000
O2.................................        1.919[sdot]10-\5\          273          139  190 to 2000      <= 2500
N2.................................        1.663[sdot]10-\5\          273          107  100 to 1500      <= 1600
----------------------------------------------------------------------------------------------------------------
\a\ Use tabulated parameters only for the pure gases, as listed. Do not combine parameters in calculations to
  calculate viscosities of gas mixtures.
\b\ The model results are valid only for ambient conditions in the specified ranges.

Example:
[mu]0 = 1.716[sdot]10-5 kg/(m[sdot]s)
T0 = 273 K
S = 111 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.109

[mu] = 1.838[sdot]10-5 kg/(m[sdot]s)
Tin = 298.15 K
dt = 152.4 mm = 0.1524 m
[rho] = 1.1508 kg/m\3\
[GRAPHIC] [TIFF OMITTED] TP21MY13.110

    Re = 1.2531[sdot]10\6\

    (vii) Calculate [rho] using the following equation:
    [GRAPHIC] [TIFF OMITTED] TP21MY13.111

Example:
[GRAPHIC] [TIFF OMITTED] TP21MY13.112

[rho] = 1.1508 kg/m\3\

    (vii) Create an equation for Cd as a function of
Re, using paired values of the two quantitites. The
equation may involve any mathematical expression, including a
polynomial or a power series. The following equation is an example of a
commonly used mathematical expression for relating Cd and
Re:
[GRAPHIC] [TIFF OMITTED] TP21MY13.113

    (viii) Perform a least-squares regression analysis to determine the
best-fit coefficients for the equation and calculate the equation's
regression statistics, SEE and r\2\, according to Sec.  1065.602.
    (ix) If the equation meets the criteria of SEE <= (0.5% [sdot]
Qrefmax) and r\2\ >= 0.995, you may use the equation to
determine Cd for emission tests, as described in Sec.
1065.642.
    (x) If the equation does not meet the specified statistical
criteria, you may use good engineering judgment to omit calibration
data points; however, you must use at least seven calibration data
points to demonstrate that you meet the criteria. For example, this may
involve narrowing the range of flow rates for a better curve fit.
    (xi) Take corrective action if the equation does not meet the
specified statistical criteria even after omitting calibration data
points. For example, select another mathematical expression for the
Cd versus Re equation, check for leaks,
or repeat the calibration process. If you must repeat the calibration
process, we recommend applying tighter tolerances to measurements and
allowing more time for flows to stabilize.
    (xii) Once you have an equation that meets the specified
statistical criteria, you may use the equation only for the
corresponding range of flow rates.
    (c) 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 calibration
coefficient, Kv, for each venturi, or calibrate each
combination of venturis as one venturi by determining Kv for
the system.
    (1) To determine Kv for a single venturi or a
combination of venturis, perform the following steps:
    (i) Calculate an individual Kv for each calibration set
point for each restrictor position using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.114

Where:
Q&refstd> = mean flow rate from the reference
flow meter, at standard reference conditions.
Tin> = mean temperature at the venturi inlet.
Pin> = mean static absolute pressure at the venturi
inlet.

    (ii) Calculate the mean and standard deviation of all the
Kv values (see 40 CFR 1065.602). Verify choked flow by
plotting Kv as a function of Pin.Kv
will have a relatively constant value for choked flow; as vacuum
pressure increases, the venturi will become unchoked and Kv
will decrease. Paragraphs (c)(1)(iii) through (viii) of this section
describe how to verify your range of choked flow.
    (iii) If the standard deviation of all the Kv values is
less than or equal to 0.3% of the mean Kv, use the mean
Kv in Eq. 1066.652-7, and use the CFV only up to the highest
venturi pressure ratio, r, measured during calibration using the
following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.115

Where:

[Delta]pCFV = differential static pressure; venturi inlet
minus venturi outlet.
    (iv) If the standard deviation of all the Kv values
exceeds 0.3% of the mean Kv, omit the Kv value
corresponding to the data point collected at the highest r measured
during calibration.
    (v) 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.
    (vi) If the number of remaining Kv values is seven or
greater, recalculate the mean and standard deviation of the remaining
Kv values.
    (vii) If the standard deviation of the remaining Kv
values is less than or equal to 0.3% of the mean of the remaining
Kv, use that mean Kv in Eq 1066.652-7, and use
the CFV values only up to the highest r associated with the remaining
Kv.
    (viii) If the standard deviation of the remaining Kv
still exceeds 0.3% of the mean of the remaining Kv values,
repeat the steps in paragraph (c)(1)(iv) through (vii) of this section.
    (2) During exhaust emission tests, monitor sonic flow in the CFV by
monitoring the CFV pressure ratio. Based on the calibration data
selected to meet the criteria for paragraphs (c)(1)(iv) and (vii) of
this section, in which Kv is constant, select the data
values associated with the calibration point with the lowest absolute
venturi inlet pressure to determine the r limit. Calculate r during the
exhaust emission test using Eq. 1066.650-8 to demonstrate that the
value of r during all emission tests is less than or equal to the r
limit derived from the CFV calibration data.

Sec.  1066.652  PDP, SSV, and CFV flow rate calculations.

    This section describes the equations for calculating flow rates
from various flow meters. After you calibrate a flow meter according to
Sec.  1066.650, use the calculations described in this section to
calculate flow during an emission test. Calculate flow according to 40
CFR 1065.642 instead if you calculate emissions based on molar flow
rates.
    (a) PDP volumetric flow rate. Based upon the speed at which you
operate the PDP for a test interval, select the corresponding slope,
a1, and intercept, a0, as calculated in Sec.
1066.650(a), to calculate volumetric flow rate, Q as follows:
[GRAPHIC] [TIFF OMITTED] TP21MY13.116

Where:

fnPDP = pump speed.
Vrev = PDP volume pumped per revolution.
Tstd = standard temperature = 293.15 K.
pin = static absolute pressure at the PDP inlet.
Tin = pump inlet absolute temperature.
pstd = standard pressure = 101.325 kPa.
P\out\ = static absolute pressure at the PDP outlet.
[GRAPHIC] [TIFF OMITTED] TP21MY13.117

Example:

a1 = 50.43 m\3\/min = 0.8405 m\3\/s
[fnof]nPDP = 755.0 r/min = 12.58 r/s
p\out\ = 99.950 kPa
p\in\ = 98.575 kPa
a0 = 0.056 m\3\/r
T\in\ = 323.5 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.118

    Vrev = 0.063 m\3\/r
    [GRAPHIC] [TIFF OMITTED] TP21MY13.119

Q = 0.7079 m\3\/s

    (b) SSV volumetric flow rate. Calculate SSV volumetric flow rate
during an emission test, Q, as follows:

[GRAPHIC] [TIFF OMITTED] TP21MY13.120

Where:

Cd = discharge coefficient, as determined based on the
Cd versus Re equation in Sec.
1066.650(b)(2)(viii).
Cf = flow coefficient, as determined in Sec.  1066.650
(b)(2)(ii).
At = venturi throat cross-sectional area.
R = molar gas constant.
pin = static absolute pressure at the venturi inlet.
Tstd = standard temperature.
pstd = standard pressure.
Z = compressibility factor.
Mmix = molar mass of gas mixture.
Tin = absolute temperature at the venturi inlet.

Example:

Cd = 0.890
Cf = 0.274
At = 0.01824 m\2\
R = 8.314472 J/(mol[middot]K) = 8.314472 (m\2\[middot]kg)/
(s\2\[middot]mol[middot]K)
pin = 98.496 kPa
Tstd = 293.15 K
pstd = 101.325 kPa
Z = 1
Mmix = 28.7789 g/mol = 0.0287789 kg/mol
Tin = 296.85 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.121

Q = 1.252 m\3\/s

    (c) CFV volumetric flow rate. 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. If you
use multiple venturis and you calibrated each venturi independently to
determine a separate calibration coefficient, Kv, for each
venturi, calculate the individual volumetric flow rates through each
venturi and sum all their flow rates to determine Q. If you use
multiple venturis and you calibrated each combination of venturis,
calculate Q using the Kv that was determined for that
combination of venturis.
    (1) To calculate volumetric flow rate through one venturi or a
combination of venturis, use the mean Kv you determined
according to Sec.  1066.650(c) and calculate the appropriate volumetric
flow rate, Q, during an emission test as follows:
[GRAPHIC] [TIFF OMITTED] TP21MY13.122

Where:

Q = air flow rate of flow meter, in m\3\/s.
Kv = flow meter calibration coefficient, in
m\3\[middot]K1/2/(kPa[middot]s).
Tin = temperature at the venturi inlet, in K.
pin = absolute static pressure at the venturi inlet, in
kPa.

Example:

Kv = 0.074954 m\3\[middot]K1/2/(kPa[middot]s)
pin = 99.654 kPa
Tin = 353.15 K
[GRAPHIC] [TIFF OMITTED] TP21MY13.123

Q = 0.39748 m\3\/s

    (2) [Reserved]

Sec.  1066.665  NMOG determination.

    For vehicles subject to an NMOG standard, determine NMOG as
described in paragraph (a) of this section. Except as specified in the
standard-setting part, you may alternatively calculate NMOG results
based on measured NMHC emissions as described in paragraphs (c) through
(f) of this section.
    (a) Determine NMOG by independently measuring alcohols and
carbonyls as described in 40 CFR 1065.805 and 1065.845. Use good
engineering judgment to determine which alcohols and carbonyls you need
to measure. This would typically require you to measure all alcohols
and carbonyls that you expect to contribute 1% or more of total NMOG
emissions. Calculate NMOG with the following equation, using density
values specified in Sec.  1066.1005(f):
[GRAPHIC] [TIFF OMITTED] TP21MY13.124

Where:

mNMOG = the sum of the mass of NMOG in the exhaust.
mNMHC = the mass of NMHC and all oxygenated hydrocarbons
(OHCs) in the exhaust, as determined using Eq. 1066.610-1. Calculate
NMHC mass based on [rho]NMHC.
[rho]NMHC = the effective C1-equivalent
density of NMHC as specified in Sec.  1066.1005(f):.
mOHCi = the mass of oxygenated species i in the exhaust
calculated using Eq. 1066.610-1.
[rho]OCHi = the C1-equivalent density of
oxygenated species i.
RFOHCi[THC-FID] = The response factor of a THC-FID to
oxygenated species i relative to propane on a C1-
equivalent basis as determined in 40 CFR 1065.665.

    (b) The following example shows how to determine NMOG emissions as
described in paragraph (a) of this section for (OHC) compounds
including ethanol (C2H5OH), methanol
(CH3OH), acetaldehyde (C2H4O), and
formaldehyde (C2HO) as C1-equivalent
concentrations:

mNMHC = 0.0125 g
mCH3OH = 0.0002 g
mC2H5OH = 0.0009 g
mHCHO = 0.0001 g
mC2H4O = 0.00005 g
RFCH3OH[THC-FID] = 0.63
RFC2H5OH[THC-FID] = 0.75
RFHCHO[THC-FID] = 0.00
RFC2H4O[THC-FID] = 0.50
[rho]NMHC-liq = 576.816 g/m\3\
[rho]CH3OH = 1332.02 g/m\3\
[rho]C2H5OH = 957.559 g/m\3\
[rho]HCHO = 1248.21 g/m\3\
[rho]C2H4O = 915.658 g/m\3\

[GRAPHIC] [TIFF OMITTED] TP21MY13.125

0.0002 + 0.0009 + 0.0001 + 0.00005
mNMOG = 0.013273

    (c) For ethanol-gasoline blends less than 25% ethanol by volume,
you may calculate NMOG emissions from measured NMHC emissions as
follows:
    (1) For hot-start and hot running test cycles or intervals other
than the FTP, you may determine NMOG based on the test cycle NMHC
emission rate using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.126

Where:
eNMOGhot = mass emission rate of NMOG over the hot running
test cycle.
eNMHChot = mass emission rate of NMHC over the hot running
test cycle, calculated using [rho]NMHC-liq.

Example:

eNMHChot = 0.025 g/mi
eNMOGhot = 0.025 [middot] 1.03 = 0.026 g/mi

    (2) You may determine weighted composite NMOG for FTP testing based
on the weighted composite NMHC emission rate and the volume percent of
ethanol in the fuel using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.127

Where:

eNMOGcomp = weighted composite mass emission rate of
NMOG.
eNMHCcomp = weighted composite mass emission rate of
NMHC, calculated using [rho]NMHC-liq.
VPEtOH = volume percentage of ethanol in the test fuel.
Use good engineering judgment to determine this value either as
specified in 40 CFR 1065.710 or based on blending volumes, taking
into account any denaturant.

Example:
eNMHCcomp = 0.025 g/mi

eNMOGcomp = 0.025 [middot] (1.0302 + 0.0071 [middot] 15.1) =
0.0284 g/mi

VPEtOH = 15.1%
    (3) You may determine NMOG for the complete FTP cold-start test
interval for use in fuel economy and CREE calculations based on the
NMHC emission rate for the test interval and the volume percent of
ethanol in the fuel using the following equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.128

Where:

eNMOG-FTPct = mass emission rate of NMOG over the FTP
cold start test interval.
eNMHC-FTPct = mass emission rate of NMHC over the FTP
cold-start test interval, calculated using [rho]NMHC-liq.
VPEtOH = volume percentage of ethanol in the test fuel.

Example:
eNMHC-FTPct = 0.052 g/mi
VPEtOH = 15.1%
eNMOG-FTPct = 0.052[middot]1.0246 + 0.0079[middot]15.1) =
0.0595 g/mi

    (4) You may determine NMOG for the FTP stabilized test interval for
either the cold-start or hot-start test for use in fuel economy and
CREE calculations based on the NMHC emission rate for the test interval
and the volume percent of ethanol in the fuel using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP21MY13.129

Where:

eNMOG-FTPcs-hs = mass emission rate of NMOG over the FTP
stabilized test interval.
eNMHC-FTPcs-hs = mass emission rate of NMHC over the FTP
stabilized test interval, calculated using [rho]NMHC-liq.
VPEtOH = volume percentage of ethanol in the test fuel.

    (5) You may determine NMOG for the complete FTP hot-start test
interval for use in fuel economy and CREE calculations based on the
NMHC emission rate for the test interval and the volume percent of
ethanol in the fuel using the following equation:

[GRAPHIC] [TIFF OMITTED] TP21MY13.130

Where:

eNMOG-FTPht = mass emission rate of NMOG over the FTP
hot-start test interval.
eNMHC-FTPht = mass emission rate of NMHC over the FTP
hot-start test interval, calculated using [rho]NMHC-liq.
VPEtOH = volume percentage of ethanol in the test fuel.

    (d) You may take the following additional steps when determining
fuel economy and CREE under 40 CFR part 600:
    (1) Calculate NMOG by interval using Eq. 1066.665-3 for individual
bag measurements from the FTP.
    (2) Calculate NMOG for two-bag FTPs using Eq. 1066.665-3 for
hybrid-electric vehicles as described in 40 CFR 600.114.
    (e) We consider NMOG emission values for diesel-fueled vehicles,
CNG-fueled vehicles, and LPG-fueled vehicles to be equivalent to NMHC
emission values for all test cycles.
    (f) For all fuels not covered by paragraphs (c) and (e) of this
section, manufacturers may propose a methodology to calculate NMOG
results from measured NMHC emissions. We will approve adjustments based
on comparative testing that demonstrates how to properly represent NMOG
based on measured NMHC emissions.

Sec.  1066.695  Data requirements.

    Record the following information for each test:
    (a) Test number.
    (b) A brief description of the test vehicle (or other system/device
tested).
    (c) Date and time of day for each part of the test sequence.
    (d) Test results. Also include a validation of driver accuracy as
described in Sec.  1066.430(j).
    (e) Driver and equipment operators.
    (f) Vehicle information as applicable, including identification
number, model year, applicable emission standards, vehicle model,
vehicle class, carline, test group, durability group, engine family,
evaporative/refueling emission family, basic engine description
(including displacement, number of cylinders, turbocharger/supercharger
used, and catalyst type), fuel system (type of fuel injection and fuel
tank capacity and location), engine code, gross vehicle weight rating,
equivalent test weight, inertia weight class, actual curb weight at
zero miles, actual road load at 50 mph, transmission class and
configuration, axle ratio, odometer reading, idle rpm, and drive wheel
tire pressure.
    (g) Dynamometer identification, inertia weight setting, indicated
power absorption setting, and records to verify compliance with the
driving distance and cycle-validation criteria as calculated from
measured roll or shaft revolutions.
    (h) Analyzer bench identification, analyzer ranges, recordings of
analyzer output during zero, span, and sample readings.
    (i) Associate the following information with the test record: Test
number, date, vehicle identification, vehicle and equipment operators,
and identification of the measurements recorded.
    (j) Test cell barometric pressure and humidity. You may use a
central laboratory barometer if the barometric pressure in each test
cell is shown to be within 0.1% of the barometric pressure
at the central barometer location.
    (k) Records to verify compliance with the ambient temperature
requirements throughout the test procedure and records of fuel
temperatures during the running loss test.
    (l) [Reserved]
    (m) For CVS systems record, dilution factor for each interval of
the exhaust test and the following additional information:
    (1) CFV and SSV Vmix for each interval of the exhaust
test.
    (2) PDP. Test measurements required to calculate Vmix
for each interval of the exhaust test.
    (n) The humidity of the dilution air if you remove H2O
from an emission sample before measurement.
    (o) Temperature of the dilute exhaust mixture and secondary
dilution air (in the case of a double-dilution system) at the inlet to
the respective gas meter or flow instrumentation used for particulate
sampling.
    (p) The maximum gas temperature over the course of the test within
20 cm upstream or downstream of the sample media (e.g., filter).
    (q) If applicable, the temperature of the heated FID, the gas in
the heated sample line, and the heated filter.
    (r) Gas meter or flow measurement instrumentation readings at the
start and end of each test interval.
    (s) The stabilized pre-test weight and post-test weight of each
particulate sample media (e.g., filter).
    (t) Continuous temperature and humidity of the ambient air in which
the particulate sample media (e.g., filter) are stabilized.
    (u) For vehicles fueled by natural gas, the test fuel composition,
including all carbon-containing compounds (except CO); e.g.
CO2, of the natural gas-fuel used during the test. Record
C1 and C2 compounds individually. You may record
C3 through C5 hydrocarbons together, and you may
record C6 and heavier hydrocarbon compounds together.
    (v) Additional required records for liquefied petroleum gas-fueled
vehicles. For vehicles fueled by liquefied petroleum gas, the test fuel
composition, including all carbon-containing compounds (except CO);
e.g. CO2. Each hydrocarbon compound present, through
C4 compounds, shall be individually reported. C5
and heavier hydrocarbons may be reported as a group. Record
C1 and C4 compounds individually. You may record
C5 and heavier hydrocarbon compounds together.

Subpart H--Cold-Temperature Test Procedures

Sec.  1066.701  Applicability and general provisions.

    (a) The procedures of this part 1066 may be used for testing at any
ambient temperature. Section 1066.710 describes the provisions that
apply for testing testing motor vehicles at a nominal temperature of 20
[deg]C (68[emsp14][deg]F); these procedures apply for motor vehicles as
described in 40 CFR part 86, subpart S, and 40 CFR part 600. For other
vehicles, see the standard-setting part to determine if your vehicle is
required to meet emission standards outside the normal (20 to 30)
[deg]C (68 to 86[emsp14][deg]F) temperature range.
    (b) Do not apply the humidity correction factor in Sec.
1066.630(a) for cold-temperature testing.

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

    This section describes procedures for measuring carbon monoxide
(CO) and nonmethane hydrocarbon (NMHC) emissions and determining fuel
economy on a cold day using the FTP driving schedule (see Sec.
1066.801).
    (a) Follow the exhaust emission measurement procedures specified in
Sec. Sec.  1066.410 through 1066.430 and

Sec.  1066.820(d), subject to the following exceptions and additional
provisions:
    (1) Measure and control ambient conditions as specified in
paragraph (b) of this section.
    (2) Precondition and stabilize the vehicle as specified in
paragraphs (c) and (d) of this section. Ensure that there is no
precipitation or dew on the vehicle before the emission test.
    (3) For dynamometers that have independently heated bearings, start
the emission test within 20 minutes after the end of dynamometer warm
up; for other dynamometers, start the emission test within 10 minutes
after the end of dynamometer warm up.
    (4) Analyze samples for NMHC, CO, and CO2. You do not
need to analyze samples for other pollutants.
    (b) Maintain ambient conditions as follows instead of following the
specifications in subpart E of this part:
    (1) Ambient temperature for emission tests. Measure and record
ambient temperature in the test cell at least once every 60 seconds
during the sampling period. The average temperature during the sampling
period must be (-7.0 1.7) [deg]C. Instantaneous temperature
values may be above -4.0 [deg]C or below -9.0 [deg]C, but not for more
than 3 minutes at a time.
    (2) Ambient temperature for preconditioning. Ambient temperatures
must be between (-14.0 and -1.0) [deg]C throughout the preconditioning
period. The average ambient temperature during preconditioning must be
(-7.0 2.8) [deg]C. You may precondition vehicles at
temperatures above -7.0 [deg]C or with a temperature tolerance greater
than that described in this section (or both) if you determine that
this will not cause NMHC, CO, or CO2 emissions to decrease;
if you modify the temperature specifications for vehicle
preconditioning, adjust the procedures described in this section
appropriately for your testing. Use good engineering judgment to
demonstrate that you meet the specified temperature tolerances
specified in this paragraph (b)(2).
    (3) Ambient humidity. Maintain humidity low enough to prevent
condensation on the dynamometer rolls during testing.
    (c) Take the following steps to prepare and precondition vehicles
for testing under this section:
    (1) Prepare the vehicle as described in Sec.  1066.814(a).
    (2) Fill the fuel tank to approximately 40% of the manufacturer's
nominal fuel tank capacity with the appropriate test fuel for low-
temperature testing specified 40 CFR part 1065, subpart H. If the
leftover fuel in the fuel tank before the refueling event does not meet
these specifications, drain the fuel tank before refueling. The
temperature of the dispensed test fuel must be at or below 15.5 [deg]C.
    (3) You may start the preconditioning drive once the fuel in the
fuel tank reaches (-7.0 [deg]C 5.6) [deg]C. Precondition
the vehicle as follows:
    (i) Push or drive the vehicle onto the dynamometer.
    (ii) Operate the vehicle over one UDDS. You may perform additional
vehicle preconditioning with repeated driving over the UDDS, subject to
our advance approval.
    (iii) Turn off the test vehicle and any cooling fans within 5
minutes after completing the preconditioning drive. Ambient temperature
must be between (-12.0 to -1.0) [deg]C in the 5 minutes following the
preconditioning drive.
    (iv) Do not manually purge or load the evaporative canister.
    (d) Soak the vehicle for (12 to 36) hours to stabilize it at test
temperatures before starting the emission test as described in this
paragraph (d). If you move a stabilized vehicle through a warm area
when transporting it to the dynamometer for testing, you must
restabilize the vehicle by holding it at an ambient temperature within
the range specified in paragraph (b)(1) of this section for at least
six times as long as the vehicle was exposed to warmer temperatures.
Use one of the following methods to reach a stabilized condition:
    (1) Cold storage. Measure and record ambient temperature in the
test cell at least once every 60 seconds during the soak period; use
these measured values to calculate an hourly average temperature. Each
hourly average temperature must be (-7.0 [deg]C 2.8)
[deg]C. Instantaneous ambient temperatures during the soak period may
be above -1.0 [deg]C or below -12.0, but not for more than 3 minutes at
a time.
    (2) Forced-cooling or warming. Position fans to blow temperature-
controlled air onto the vehicle to stabilize the vehicle at the
specified temperatures for emission testing. Position fans to target
the vehicle's drive train, engine block, and radiator rather than the
oil pan. You may not place fans under the vehicle. You may consider the
vehicle to be stabilized at the test temperature when the bulk oil
temperature reaches (-7 1.7) [deg]C; measure oil
temperature at one or more points away from the side or bottom surfaces
of the oil pan. Each oil temperature measurement must be within the
specified range before stabilization is complete. Once the vehicle
reaches this stabilized condition, hold the vehicle within the
stabilized temperature range for at least one hour before starting the
emission test. During this time, keep the ambient temperature within
the range specified in paragraph (b)(1) of this section.

Subpart I--Exhaust Emission Test Procedures for Motor Vehicles

Sec.  1066.801  Applicability and general provisions.

    This subpart I specifies how to apply the test procedures of this
part for motor vehicles at or below 14,000 pounds GVWR, including
light-duty vehicles, light-duty trucks, and heavy-duty vehicles at or
below 14,000 pounds GVWR that are subject to chassis testing for
exhaust emissions. For these vehicles, references in this part 1066 to
the standard-setting part include this subpart I.
    (a) Use the procedures detailed in this subpart to measure vehicle
emissions over a specified drive schedule in conjunction with subpart E
of this part. Where the procedures of subpart E of this part differ
from this subpart I, the provisions in this subpart I take precedence.
    (b) Collect samples of every pollutant for which an emission
standard applies, unless specified otherwise.