(iii) If you are verifying over the entire duty cycle, calculate
composite brake-specific emission values.
    (3) The duty cycle is verified for drift if you satisfy the
following criteria:
    (i) For each regulated gaseous exhaust constituent, you must
satisfy one of the following:
    (A) For each test interval of the duty cycle, the difference
between the uncorrected and the corrected brake-specific emission
values of the regulated constituent must be within 4% of
the uncorrected value or the applicable emissions standard, whichever
is greater. Alternatively, the difference between the uncorrected and
the corrected emission mass (or mass rate) values of the regulated
constituent must be within 4% of the uncorrected value or
the composite work (or power) multiplied by the applicable emissions
standard, whichever is greater. For purposes of verifying each test
interval, you may use either the reference or actual composite work (or
power).
    (B) For each test interval of the duty cycle and for each mass
subcomponent of the regulated constituent, the difference between the
uncorrected and the corrected brake-specific emission values must be
within 4% of the uncorrected value. Alternatively, the
difference between the uncorrected and the corrected emissions mass (or
mass rate) values must be within 4% of the uncorrected
value.
    (C) For the entire duty cycle, the difference between the
uncorrected and the corrected composite brake-specific emission values
of the regulated constituent must be within 4% of the
uncorrected value or applicable emission standard, whichever is
greater.
    (D) For the entire duty cycle and for each subcomponent of the
regulated constituent, the difference between the uncorrected and the
corrected composite brake-specific emission values must be within
4% of the uncorrected value.
    (ii) Where no emission standard applies for CO2, you
must satisfy one of the following:
    (A) For each test interval of the duty cycle, the difference
between the uncorrected and the corrected brake-specific CO2
values must be within 4% of the uncorrected value; or the
difference between the uncorrected and the corrected CO2
mass (or mass rate) values must be within 4% of the
uncorrected value.
    (B) For the entire duty cycle, the difference between the
uncorrected and the corrected composite brake-specific CO2
values must be within 4% of the uncorrected value.
    (4) If the test is not verified for drift as described in paragraph
(b)(1) of this section, you may consider the test results for the duty
cycle to be valid only if, using good engineering judgment, the
observed drift does not affect your ability to demonstrate compliance
with the applicable emission standards. For example, if the drift-
corrected value is less than the standard by at least two times the
absolute difference between the uncorrected and corrected values, you
may consider the data to be verified for demonstrating compliance with
the applicable standard.

Subpart G--[Amended]

0
299. Section 1065.601 is amended by revising paragraph (b) to read as
follows:

Sec.  1065.601  Overview.

* * * * *
    (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 weighings 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.
    (1) We allow weighted means where appropriate.
    (2) You may discard statistical outliers, but you must report all
results.
    (3) For emission measurements related to durability testing, we may
allow you to exclude certain test points other than statistical
outliers relative to compliance with emission standards, consistent
with good engineering judgment and normal measurement variability;
however, you must include these results when calculating the
deterioration factor. This would allow you to use durability data from
an engine that has an intermediate test result above the standard that
cannot be discarded as a statistical outlier, as long as good
engineering judgment indicates that the test result does not represent
the engine's actual emission level. Note that good engineering judgment
would preclude you from excluding endpoints. Also, if normal
measurement variability causes emission results below zero, include the
negative result in calculating the deterioration factor to avoid an
upward bias. These provisions related to durability testing are
intended to address very stringent standards where measurement
variability is large relative to the emission standard.
* * * * *

0
300. Section 1065.602 is amended by revising paragraphs (f), (j), (k),
and (l)(1)(ii) to read as follows:

Sec.  1065.602  Statistics.

* * * * *
    (f) t-test. Determine if your data passes a t-test by using the
following equations and tables:
    (1) For an unpaired t-test, calculate the t statistic and its
number of degrees of freedom, as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.010

    (2) For a paired t-test, calculate the t statistic and its number
of degrees of freedom, as follows, noting that the [egr]i are the
errors (e.g., differences) between each pair of yrefi and
yi:

[GRAPHIC] [TIFF OMITTED] TR28AP14.011

[GRAPHIC] [TIFF OMITTED] TR28AP14.012

 Table 1 of Sec.   1065.602--Critical t Values Versus Number of Degrees
                            of Freedom, v \1\
------------------------------------------------------------------------
                                                       Confidence
                     [nu]                      -------------------------
                                                    90%          95%
------------------------------------------------------------------------
1.............................................        6.314       12.706
2.............................................        2.920        4.303
3.............................................        2.353        3.182
4.............................................        2.132        2.776
5.............................................        2.015        2.571
6.............................................        1.943        2.447
7.............................................        1.895        2.365
8.............................................        1.860        2.306
9.............................................        1.833        2.262
10............................................        1.812        2.228
11............................................        1.796        2.201
12............................................        1.782        2.179
13............................................        1.771        2.160
14............................................        1.761        2.145
15............................................        1.753        2.131
16............................................        1.746        2.120
18............................................        1.734        2.101
20............................................        1.725        2.086
22............................................        1.717        2.074
24............................................        1.711        2.064
26............................................        1.706        2.056
28............................................        1.701        2.048
30............................................        1.697        2.042
35............................................        1.690        2.030
40............................................        1.684        2.021
50............................................        1.676        2.009
70............................................        1.667        1.994
100...........................................        1.660        1.984
1000+.........................................        1.645        1.960
------------------------------------------------------------------------
\1\ Use linear interpolation to establish values not shown here.

* * * * *
    (j) Standard estimate of error. Calculate a standard estimate of
error, SEE, as follows:

[GRAPHIC] [TIFF OMITTED] TR28AP14.013

[GRAPHIC] [TIFF OMITTED] TR28AP14.014

    (l) * * *
    (1) * * *
    (ii) Based on your engine design, estimate maximum power,
Pmax, the design speed at maximum power, fnmax,
the design maximum intake manifold boost pressure, pinmax,
and temperature, Tinmax. Also, estimate a mean fraction of
power that is lost due to friction and pumping, pfrict. Use
this information along with the engine displacement volume,
Vdisp, an approximate volumetric efficiency,
[eta]V, and the number of engine strokes per power stroke
(two-stroke or four-stroke), Nstroke, to estimate the
maximum raw exhaust molar flow rate, nexhmax.
* * * * *

0
301. Section 1065.610 is amended by revising paragraphs (a)
introductory text, (a)(1), (c)(3), and (d)(3)(ii) to read as follows:

Sec.  1065.610  Duty cycle generation.

* * * * *
    (a) Maximum test speed, fntest. This section generally
applies to duty cycles for variable-speed engines. For constant-speed
engines subject to duty cycles that specify normalized speed commands,
use the no-load governed speed as the measured fntest. This
is the highest engine speed where an engine outputs zero torque. For
variable-speed engines, determine fntest as follows:
    (1) Develop a measured value for fntest as follows:
    (i) Determine maximum power, Pmax, from the engine map
generated according to Sec.  1065.510 and calculate the value for power
equal to 98% of Pmax.
    (ii) Determine the lowest and highest engine speeds corresponding
to 98% of Pmax, using linear interpolation as appropriate.
    (iii) Determine the engine speed corresponding to maximum power,
fnPmax, by calculating the average of the two speed values
from paragraph (a)(1)(ii) of this section.
    (iv) Transform the map into a normalized power-versus-speed map by
dividing power terms by Pmax and dividing speed terms by
fnPmax. Use the following equation to calculate a quantity
representing the sum of squares from the normalized map:
[GRAPHIC] [TIFF OMITTED] TR28AP14.015

    (v) Determine the maximum value for the sum of the squares from the
map and multiply that value by 0.98.

[GRAPHIC] [TIFF OMITTED] TR28AP14.016

* * * * *
    (c) * * *
    (3) Intermediate speed. Based on the map, determine maximum torque,
Tmax, and the corresponding speed, fnTmax,
calculated as the average of the lowest and highest speeds at which
torque is equal to 98% of Tmax. Use linear interpolation
between points to determine the speeds where torque is equal to 98% of
Tmax. Identify your reference intermediate speed as one of
the following values:
    (i) fnTmax if it is between (60 and 75) % of maximum
test speed.
    (ii) 60% of maximum test speed if fnTmax is less than
60% of maximum test speed.
    (iii) 75% of maximum test speed if fnTmax is greater
than 75% of maximum test speed.
    (d) * * *
    (3) * * *
    (ii) If the cycle begins with a set of contiguous idle points
(zero-percent speed, and zero-percent torque), leave the reference
torques set to zero for this initial contiguous idle segment. This is
to represent free idle operation with the transmission in neutral or
park at the start of the transient duty cycle, after the engine is
started. If the initial idle segment is longer than 24 seconds, change
the reference torques for the remaining idle points in the initial
contiguous idle segment to CITT (i.e., change idle points corresponding
to 25 seconds to the end of the initial idle segment to CITT). This is
to represent shifting the transmission to drive.
* * * * *

0
302. Section 1065.630 is revised to read as follows:

Sec.  1065.630  Local acceleration of gravity.

    (a) The acceleration of Earth's gravity, ag, varies
depending on the test location. Determine ag at your
location by entering latitude, longitude, and elevation data into the
U.S. National Oceanographic and Atmospheric Administration's surface
gravity prediction Web site at http://www.ngs.noaa.gov/cgi-bin/grav_pdx.prl.
    (b) If the Web site specified in paragraph (a) of this section is
unavailable, you may calculate ag for your latitude as
follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.143

Where:

[thgr] = Degrees north or south latitude.
Example:
[thgr] = 45[deg]
ag = 9.7803267715 [middot] (1 + 5.2790414 [middot]
10-\3\[middot]sin\2\ (45) + 2.32718 [middot]
10-\5\[middot]sin\4\ (45) + 1.262 [middot]
10-\7\[middot]sin\6\ (45) + 7 [middot]
10-\10\[middot]sin\8\ (45)
ag = 9.8061992026 m/s \2\

0
303. Section 1065.640 is revised to read as follows:

Sec.  1065.640  Flow meter calibration calculations.

    This section describes the calculations for calibrating various
flow meters. After you calibrate a flow meter using these calculations,
use the calculations described in Sec.  1065.642 to calculate flow
during an emission test. Paragraph (a) of this section first describes
how to convert reference flow meter outputs for use in the calibration
equations, which are presented on a molar basis. The remaining
paragraphs describe the calibration calculations that are specific to
certain types of flow meters.
    (a) Reference meter conversions. The calibration equations in this
section use molar flow rate, nref, as a reference quantity.
If your reference meter outputs a flow rate in a different quantity,
such as standard volume rate, Vstdref, actual volume rate,
Vactref, or mass rate, mref, convert your
reference meter output to a molar flow rate using the following
equations, noting that while values for volume rate, mass rate,
pressure, temperature, and molar mass may change during an emission
test, you should ensure that they are as constant as practical for each
individual set point during a flow meter calibration:
[GRAPHIC] [TIFF OMITTED] TR28AP14.017

Where:

nref = reference molar flow rate.
Vstdref = reference volume flow rate, corrected to a
standard pressure and a standard temperature.
Vactref = reference volume flow rate at the actual
pressure and temperature of the flow rate.
mref = reference mass flow.
pstd = standard pressure.
pact = actual pressure of the flow rate.
Tstd = standard temperature.
Tact = actual temperature of the flow rate.
R = molar gas constant.
Mmix = molar mass of the flow rate.

[GRAPHIC] [TIFF OMITTED] TR28AP14.018

[GRAPHIC] [TIFF OMITTED] TR28AP14.019

    (3) Perform a least-squares regression of PDP volume pumped per
revolution, Vrev, versus PDP slip correction factor,
Ks, by calculating slope, a1, and intercept,
a0, as described in Sec.  1065.602.
    (4) Repeat the procedure in paragraphs (b)(1) through (3) of this
section for every speed that you run your PDP.
    (5) The following example illustrates these calculations:

       Table 1 of Sec.   1065.640--Example of PDP Calibration Data
------------------------------------------------------------------------
                                                  a1 (m\3\/   a0 (m\3\/
              f8nPDP (revolution/s)                   s)     revolution)
------------------------------------------------------------------------
12.6............................................      0.841       0.056
16.5............................................      0.831      -0.013
20.9............................................      0.809       0.028
23.4............................................       .788      -0.061
------------------------------------------------------------------------

    (6) For each speed at which you operate the PDP, use the
corresponding slope, a1, and intercept, a0, to
calculate flow rate during emission testing as described in Sec.
1065.642.
    (c) Venturi governing equations and permissible assumptions. This
section describes the governing equations and permissible assumptions
for calibrating a venturi and calculating flow using a venturi. Because
a subsonic venturi (SSV) and a critical-flow venturi (CFV)

both operate similarly, their governing equations are nearly the same,
except for the equation describing their pressure ratio, r (i.e.,
rSSV versus rCFV). These governing equations
assume one-dimensional isentropic inviscid compressible flow of an
ideal gas. In paragraph (c)(4) of this section, we describe other
assumptions that you may make, depending upon how you conduct your
emission tests. If we do not allow you to assume that the measured flow
is an ideal gas, the governing equations include a first-order
correction for the behavior of a real gas; namely, the compressibility
factor, Z. If good engineering judgment dictates using a value other
than Z=1, you may either use an appropriate equation of state to
determine values of Z as a function of measured pressures and
temperatures, 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 pressures and temperatures, or you may develop
your own calibration equations based on good engineering judgment.
Calculate molar flow rate, as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.020

Where:

Cd = discharge coefficient, as determined in paragraph
(c)(1) of this section.
Cf = flow coefficient, as determined in paragraph (c)(2)
of this section.
At = venturi throat cross-sectional area.
pin = venturi inlet absolute static pressure.
Z = compressibility factor.
Mmix = molar mass of gas mixture.
R = molar gas constant.
Tin = venturi inlet absolute temperature.

    (1) Using the data collected in Sec.  1065.340, calculate Cd using
the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.021

Where:

nref = a reference molar flow rate.

    (2) Determine Cf using one of the following methods:
    (i) For CFV flow meters only, determine CfCFV from the
following table based on your values for [beta] and [gamma], using
linear interpolation to find intermediate values:

Table 2 of Sec.   1065.640--CfCFV Versus [beta] and [gamma] for CFV Flow
                                 Meters
------------------------------------------------------------------------
                                  CfCFV
-------------------------------------------------------------------------
                                                             [gamma]dexh
                                                 [gamma]exh       =
                     [beta]                        = 1.385    [gamma]air
                                                               = 1.399
------------------------------------------------------------------------
0.000..........................................      0.6822      0.6846
0.400..........................................      0.6857      0.6881
0.500..........................................      0.6910      0.6934
0.550..........................................      0.6953      0.6977
0.600..........................................      0.7011      0.7036
0.625..........................................      0.7047      0.7072
0.650..........................................      0.7089      0.7114
0.675..........................................      0.7137      0.7163
0.700..........................................      0.7193      0.7219
0.720..........................................      0.7245      0.7271
0.740..........................................      0.7303      0.7329
0.760..........................................      0.7368      0.7395
0.770..........................................      0.7404      0.7431
0.780..........................................      0.7442      0.7470
0.790..........................................      0.7483      0.7511
0.800..........................................      0.7527      0.7555
0.810..........................................      0.7573      0.7602
0.820..........................................      0.7624      0.7652
0.830..........................................      0.7677      0.7707
0.840..........................................      0.7735      0.7765
0.850..........................................      0.7798      0.7828
------------------------------------------------------------------------

    (ii) For any CFV or SSV flow meter, you may use the following
equation to calculate Cf:
[GRAPHIC] [TIFF OMITTED] TR28AP14.022

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 (c)(3) of this
section.
[beta] = ratio of venturi throat to inlet diameters.

    (3) Calculate r as follows:
    (i) For SSV systems only, calculate rSSV using the
following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.023

Where:

[Delta]pSSV = Differential static pressure; venturi inlet
minus venturi throat.

    (ii) For CFV systems only, calculate rCFV iteratively
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.024

    (4) You may make any of the following simplifying assumptions of
the governing equations, or you may use good engineering judgment to
develop more appropriate values for your testing:
    (i) For emission testing over the full ranges of raw exhaust,
diluted exhaust and dilution air, you may assume that the gas mixture
behaves as an ideal gas: Z = 1.
    (ii) For the full range of raw exhaust you may assume a constant
ratio of specific heats of [gamma] = 1.385.
    (iii) For the full range of diluted exhaust and air (e.g.,
calibration air or dilution air), you may assume a constant ratio of
specific heats of [gamma] = 1.399.
    (iv) For the full range of diluted exhaust and air, you may assume
the molar mass of the mixture is a function only of the amount of water
in the dilution air or calibration air, xH2O, determined as
described in Sec.  1065.645, as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.144

Example:

Mair = 28.96559 g/mol
xH2O = 0.0169 mol/mol
MH2O = 18.01528 g/mol
Mmix = 28.96559 [middot] (1 - 0.0169) + 18.01528 [middot]
0.0169
Mmix = 28.7805 g/mol

    (v) For the full range of diluted exhaust and air, you may assume a
constant molar mass of the mixture,

Mmix, for all calibration and all testing as long as your
assumed molar mass differs no more than 1% from the
estimated minimum and maximum molar mass during calibration and
testing. You may assume this, using good engineering judgment, if you
sufficiently control the amount of water in calibration air and in
dilution air or if you remove sufficient water from both calibration
air and dilution air. The following table gives examples of permissible
ranges of dilution air dewpoint versus calibration air dewpoint:

Table 3 of Sec.   1065.640--Examples of Dilution Air and Calibration Air
            Dewpoints at Which You May Assume a Constant Mmix
------------------------------------------------------------------------
                                     assume the      for the following
If calibration Tdew ([deg]C) is .     following        ranges of Tdew
               . .                  constant Mmix     ([deg]C) during
                                    (g/mol) . . .    emission tests \a\
------------------------------------------------------------------------
dry..............................        28.96559  dry to 18.
0................................        28.89263  dry to 21.
5................................        28.86148  dry to 22.
10...............................        28.81911  dry to 24.
15...............................        28.76224  dry to 26.
20...............................        28.68685  -8 to 28.
25...............................        28.58806  12 to 31.
30...............................        28.46005  23 to 34.
------------------------------------------------------------------------
\a\ Range valid for all calibration and emission testing over the
  atmospheric pressure range (80.000 to 103.325) kPa.

    (5) The following example illustrates the use of the governing
equations to calculate the discharge coefficient, Cd of an
SSV flow meter at one reference flow meter value. Note that calculating
Cd for a CFV flow meter would be similar, except that
Cf would be determined from Table 2 of this section or
calculated iteratively using values of [beta] and [gamma] as described
in paragraph (c)(2) of this section.

Example:

nref = 57.625 mol/s
Z = 1
Mmix = 28.7805 g/mol = 0.0287805 kg/mol
R = 8.314472 J/(mol[middot]K) = 8.314472 (m\2\[middot]kg)/
(s\2\[middot]mol[middot]K)
Tin = 298.15 K
At = 0.01824 m\2\
pin = 99.132 kPa = 99132.0 Pa = 99132 kg/(m[middot]s\2\)
[gamma] = 1.399
[beta] = 0.8
[Delta]p = 2.312 kPa
[GRAPHIC] [TIFF OMITTED] TR28AP14.025

    (d) SSV calibration. Perform the following steps to calibrate an
SSV flow meter:
    (1) Calculate the Reynolds number, Re, for each
reference molar flow rate, nref, using the throat diameter
of the venturi, dt. 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] TR28AP14.026

Where:

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

               Table 4 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/            K            K            K          kPa
                                                (m[middot]s)
----------------------------------------------------------------------------------------------------------------
Air.........................................  1.716[middot]1          273          111  170 to 1900       <=1800
                                                         0-5
CO2.........................................  1.370[middot]1          273          222  190 to 1700       <=3600
                                                         0-5
H2O.........................................  1.12[middot]10-         350         1064  360 to 1500      <=10000
                                                           5
O2..........................................  1.919[middot]1          273          139  190 to 2000       <=2500
                                                         0-5
N2..........................................  1.663[middot]1          273          107  100 to 1500       <=1600
                                                         0-5
----------------------------------------------------------------------------------------------------------------
\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[middot]10-5 kg/(m[middot]s)

[GRAPHIC] [TIFF OMITTED] TR28AP14.027

    (3) Perform a least-squares regression analysis to determine the
best-fit coefficients for the equation and calculate the equation's
regression statistic, SEE, according to Sec.  1065.602.
    (4) If the equation meets the criterion of SEE <= 0.5% [middot]
Cdmax, you may use the equation to determine Cd
for emission tests, as described in Sec.  1065.642.
    (5) If the equation does not meet the specified statistical
criterion, 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 statistical criterion. This
will usually involve narrowing the range of flow rates for a better
curve fit.
    (6) Take corrective action if the equation does not meet the
specified statistical criterion 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 process, we
recommend applying tighter tolerances to measurements and allowing more
time for flows to stabilize.
    (7) Once you have an equation that meets the specified statistical
criterion, you may use the equation only for the corresponding range of
Re.
    (e) CFV calibration. Some CFV flow meters consist of a single
venturi and some consist of multiple venturis,

where different combinations of venturis are used to meter different
flow rates. For CFV flow meters that consist of multiple venturis,
either calibrate each venturi independently to determine a separate
discharge coefficient, Cd, for each venturi, or calibrate
each combination of venturis as one venturi. In the case where you
calibrate a combination of venturis, use the sum of the active venturi
throat areas as At, the square root of the sum of the
squares of the active venturi throat diameters as dt, and
the ratio of the venturi throat to inlet diameters as the ratio of the
square root of the sum of the active venturi throat diameters
(dt) to the diameter of the common entrance to all the
venturis. (D). To determine the Cd for a single venturi or a
single combination of venturis, perform the following steps:
    (1) Use the data collected at each calibration set point to
calculate an individual Cd for each point using Eq.
1065.640-4.
    (2) Calculate the mean and standard deviation of all the
Cd values according to Eqs. 1065.602-1 and 1065.602-2.
    (3) If the standard deviation of all the Cd values is
less than or equal to 0.3% of the mean Cd, use the mean
Cd in Eq. 1065.642-4, and use the CFV only up to the highest
r measured during calibration using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.028

Where:

[Delta]pCFV = Differential static pressure; venturi inlet
minus venturi outlet.

    (4) If the standard deviation of all the Cd values
exceeds 0.3% of the mean Cd, omit the Cd value
corresponding to the data point collected at the highest r measured
during calibration.
    (5) If the number of remaining data points is less than seven, take
corrective action by checking your calibration data or repeating the
calibration process. If you repeat the calibration process, we
recommend checking for leaks, applying tighter tolerances to
measurements and allowing more time for flows to stabilize.
    (6) If the number of remaining Cd values is seven or
greater, recalculate the mean and standard deviation of the remaining
Cd values.
    (7) If the standard deviation of the remaining Cd values
is less than or equal to 0.3% of the mean of the remaining
Cd, use that mean Cd in Eq. 1065.642-4, and use
the CFV values only up to the highest r associated with the remaining
Cd.
    (8) If the standard deviation of the remaining Cd still
exceeds 0.3% of the mean of the remaining Cd values, repeat
the steps in paragraph (e)(4) through (8) of this section.

0
304. Section 1065.642 is revised to read as follows:

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

    This section describes the equations for calculating molar flow
rates from various flow meters. After you calibrate a flow meter
according to Sec.  1065.640, use the calculations described in this
section to calculate flow during an emission test.
    (a) PDP molar 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.
1065.640, to calculate molar flow rate, n as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.029

[GRAPHIC] [TIFF OMITTED] TR28AP14.030

Example:

At = 0.01824 m\2\
pin = 99.132 kPa = 99132 Pa = 99132 kg/(m[middot]s\2\)
Z = 1
Mmix = 28.7805 g/mol = 0.0287805 kg/mol
R = 8.314472 J/(mol[middot]K) = 8.314472 (m\2\[middot]kg)/
(s\2\[middot]mol[middot]K)
Tin = 298.15 K
Re = 7.232[middot]10\5\
[gamma] = 1.399
[beta] = 0.8
[Delta]p = 2.312 kPa

Using Eq. 1065.640-7,
rssv = 0.997

Using Eq. 1065.640-6,
Cf = 0.274

[GRAPHIC] [TIFF OMITTED] TR28AP14.031

    (c) CFV molar 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 discharge coefficient, Cd (or
calibration coefficient, Kv), for each venturi, calculate
the individual molar flow rates through each venturi and sum all their
flow rates to determine n. If you use multiple venturis and you
calibrated each combination of venturis, calculate n using the sum of
the active venturi throat areas as At, the square root of
the sum of the squares of the active venturi throat diameters as
dt, and the ratio of the venturi throat to inlet diameters
as the ratio of the square root of the sum of the active venturi throat
diameters (dt) to the diameter of the common entrance to all
the venturis (D).
    (1) To calculate the molar flow rate through one venturi or one
combination of venturis, use its respective mean Cd and
other constants you determined according to Sec.  1065.640 and
calculate its molar flow rate n during an emission test, as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.032

[GRAPHIC] [TIFF OMITTED] TR28AP14.033

    (2) To calculate the molar flow rate through one venturi or a
combination of venturis, you may use its respective mean,
Kv, and other constants you determined according to Sec.
1065.640 and calculate its molar flow rate during an emission test.
Note that if you follow the permissible ranges of dilution air dewpoint
versus calibration air

dewpoint in Table 3 of Sec.  1065.640, you may set Mmix-cal
and Mmix equal to 1. Calculate n as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.034

Vstdref = volume flow rate of the standard at reference
conditions of 293.15 K and 101.325 kPa.
Tin-cal = venturi inlet temperature during calibration.
Pin-cal = venturi inlet pressure during calibration.
Mmix-cal = molar mass of gas mixture used during
calibration.
Mmix = molar mass of gas mixture during the emission test
calculated using Equation 1065.640-9.

Example:
Vstdref = 0.4895 m\3\
Tin-cal = 302.52 K
Pin-cal = 99.654 kPa = 99654 Pa = 99654 kg/
(m[middot]s\2\)
pin = 98.836 kPa = 98836 Pa = 98836 kg/(m[middot]s\2\)
pstd = 101.325 kPa = 101325 Pa = 101325 kg/
(m[middot]s\2\)
Mmix-cal = 28.9656 g/mol = 0.0289656 kg/mol
Mmix = 28.7805 g/mol = 0.0287805 kg/mol
Tin = 353.15 K
Tstd = 293.15 K
R = 8.314472 J/(mol[middot]K) = 8.314472 (m\2\[middot]kg)/
(s\2\[middot]mol[middot]K)
[GRAPHIC] [TIFF OMITTED] TR28AP14.035

0
305. Section 1065.644 is revised to read as follows:

Sec.  1065.644  Vacuum-decay leak rate.

    This section describes how to calculate the leak rate of a vacuum-
decay leak verification, which is described in Sec.  1065.345(e). Use
the following equation to calculate the leak rate nleak, and
compare it to the criterion specified in Sec.  1065.345(e):
[GRAPHIC] [TIFF OMITTED] TR28AP14.036

Where:

Vvac = geometric volume of the vacuum-side of the
sampling system.
R = molar gas constant.
p2 = vacuum-side absolute pressure at time t2.
T2 = vacuum-side absolute temperature at time
t2.
p1 = vacuum-side absolute pressure at time t1.
T1 = vacuum-side absolute temperature at time
t1.
t2 = time at completion of vacuum-decay leak verification
test.
t1 = time at start of vacuum-decay leak verification
test.

Example:

Vvac = 2.0000 L = 0.00200 m\3\
R = 8.314472 J/(mol[middot]K) = 8.314472 (m\2\[middot]kg)/
(s\2\[middot]mol[middot]K)
p2 = 50.600 kPa = 50600 Pa = 50600 kg/(m[middot]s\2\)
T2 = 293.15 K
p1 = 25.300 kPa = 25300 Pa = 25300 kg/(m[middot]s\2\)
T1 = 293.15 K
t2 = 10:57:35 a.m.
t1 = 10:56:25 a.m.
[GRAPHIC] [TIFF OMITTED] TR28AP14.037

[GRAPHIC] [TIFF OMITTED] TR28AP14.038

0
306. Section 1065.645 is amended by revising the introductory text and
paragraph (a) and adding paragraph (d) to read as follows:

Sec.  1065.645  Amount of water in an ideal gas.

    This section describes how to determine the amount of water in an
ideal gas, which you need for various performance verifications and
emission calculations. Use the equation for the vapor pressure of water
in paragraph (a) of this section or another appropriate equation and,
depending on whether you measure dewpoint or relative humidity, perform
one of the calculations in paragraph (b) or (c) of this section.
Paragraph (d) of this section provides an equation for determining
dewpoint from relative humidity and dry bulb temperature measurements.
The equations for the vapor pressure of water as presented in this
section are derived from equations in ``Saturation Pressure of Water on
the New Kelvin Temperature Scale'' (Goff, J.A., Transactions American
Society of Heating and Air-Conditioning Engineers, Vol. 63, No. 1607,
pages 347-354). Note that the equations were originally published to
derive vapor pressure in units of atmospheres and have been modified to
derive results in units of kPa by converting the last term in each
equation.
    (a) Vapor pressure of water. Calculate the vapor pressure of water
for a given saturation temperature condition, Tsat, as
follows, or use good engineering judgment to use a different
relationship of the vapor pressure of water to a given saturation
temperature condition:
    (1) For humidity measurements made at ambient temperatures from (0
to 100) [deg]C, or for humidity measurements made over super-cooled
water at ambient temperatures from (-50 to 0) [deg]C, use the following
equation:

[GRAPHIC] [TIFF OMITTED] TR28AP14.039

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

[GRAPHIC] [TIFF OMITTED] TR28AP14.040

* * * * *
    (d) Dewpoint determination from relative humidity and dry bulb
temperature. This paragraph (d) describes how to calculate dewpoint
temperature from relative humidity, RH%. This is based on ``ITS-90
Formulations for Vapor Pressure, Frostpoint Temperature, Dewpoint
Temperature, and Enhancement Factors in the Range -100 to +100 [deg]C''
(Hardy, B., The Proceedings of the Third International Symposium on
Humidity & Moisture, Teddington, London, England, April 1998).
Calculate pH20sat as described in paragraph (a) of this
section based on setting Tsat equal to Tamb.
Calculate pH20scaled by multiplying pH20sat by
RH%. Calculate the dewpoint, Tdew, from pH20
using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.041

Where:

ln(pH2O) = the natural log of pH2Oscaled,
which is the water vapor pressure scaled to the relative humidity at
the location of the relative humidity measurement, Tsat =
Tamb.

[GRAPHIC] [TIFF OMITTED] TR28AP14.042

0
307. Section 1065.650 is amended by revising paragraphs (c)(1)(i),
(c)(1)(ii), and (f)(4) to read as follows:

Sec.  1065.650  Emission calculations.

* * * * *
    (c) * * *
    (1) * * *
    (i) Correct all gaseous emission analyzer concentration readings,
including continuous readings, sample bag readings, and dilution air
background readings, for drift as described in Sec.  1065.672. Note
that you must omit this step where brake-specific emissions are
calculated without the drift correction for performing the drift
validation according to Sec.  1065.550(b). When applying the initial
THC and CH4 contamination readings according to Sec.
1065.520(f), use the same values for both sets of calculations. You may
also use as-measured values in the initial set of calculations and
corrected values in the drift-corrected set of calculations as
described in Sec.  1065.520(g)(7).
    (ii) Correct all THC and CH4 concentrations for initial
contamination as described in Sec.  1065.660(a), including continuous
readings, sample bags readings, and dilution air background readings.
* * * * *
    (f) * * *
    (4) Example. The following example shows how to calculate mass of
emissions using proportional values:

N = 3000
[fnof]record = 5 Hz
efuel = 285 g/(kW[middot]hr)
wfuel = 0.869 g/g
Mc = 12.0107 g/mol
n1 = 3.922 mol/s = 14119.2 mol/hr
[chi]Ccombdry1 = 91.634 mmol/mol = 0.091634
mol/mol
[chi]H2Oexh1 = 27.21 mmol/mol = 0.02721 mol/
mol

Using Eq. 1065.650-5,
[Delta]t = 0.2 s
[GRAPHIC] [TIFF OMITTED] TR28AP14.043

W = 5.09 (kW[middot]hr)
* * * * *

0
308. Section 1065.655 is amended by revising paragraphs (c)
introductory text, (c)(3), (d), (e), and (f)(2) to read as follows:

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

* * * * *
    (c) Chemical balance procedure. The calculations for a chemical
balance involve a system of equations that require iteration. We
recommend using a computer to solve this system of equations. You must
guess the initial values of up to three quantities: The amount of water
in the measured flow, [chi]H2Oexh, fraction of
dilution air in diluted exhaust, xdil/exh, and the amount of
products on a C1 basis per dry mole of dry measured flow,
[chi]Ccombdry. You may use time-weighted mean
values of combustion air humidity and dilution air humidity in the
chemical balance; as long as your combustion air and dilution air
humidities remain within tolerances of 0.0025 mol/mol of
their respective mean values over the test interval. For each emission
concentration, [chi], and amount of water,
[chi]H2Oexh, you must determine their completely
dry concentrations, [chi]dry and
[chi]H2Oexhdry. You must also use your fuel's
atomic hydrogen-to-carbon ratio, [alpha], oxygen-to-carbon ratio,
[beta], sulfur-to-carbon ratio, [gamma], and nitrogen-to-carbon ratio,
[delta]. You may calculate [alpha], [beta], [gamma], and [delta] based
on measured fuel composition as described in paragraph (d)(1) or (d)(2)
of this section, or you may use default values for a given fuel as
described in paragraph (d)(3) of this section. Use the following steps
to complete a chemical balance:
* * * * *

    (3) Use the following symbols and subscripts in the equations for
this paragraph (c):

[chi]dil/exh = amount of dilution gas or
excess air per mole of exhaust.
[chi]H2Oexh = amount of H2O in
exhaust per mole of exhaust.
[chi]Ccombdry = amount of carbon from fuel in
the exhaust per mole of dry exhaust.
[chi]H2dry = amount of H2 in
exhaust per amount of dry exhaust.
    KH2Ogas = water-gas reaction equilibrium coefficient.
You may use 3.5 or calculate your own value using good engineering
judgment.
[chi]H2Oexhdry = amount of H2O in
exhaust per dry mole of dry exhaust.
[chi]prod/intdry = amount of dry
stoichiometric products per dry mole of intake air.
[chi]dil/exhdry = amount of dilution gas and/
or excess air per mole of dry exhaust.
[chi]int/exhdry = amount of intake air
required to produce actual combustion products per mole of dry (raw
or diluted) exhaust.
[chi]raw/exhdry = amount of undiluted exhaust,
without excess air, per mole of dry (raw or diluted) exhaust.
[chi]O2int = amount of intake air
O2 per mole of intake air.
[chi]CO2intdry = amount of intake air
CO2 per mole of dry intake air. You may use
[chi]CO2intdry = 375 [mu]mol/mol, but we recommend
measuring the actual concentration in the intake air.
[chi]H2Ointdry = amount of intake air
H2O per mole of dry intake air.
[chi]CO2int = amount of intake air
CO2 per mole of intake air.
[chi]CO2dil = amount of dilution gas
CO2 per mole of dilution gas.
[chi]CO2dildry = amount of dilution gas
CO2 per mole of dry dilution gas. If you use air as
diluent, you may use xCO2dildry = 375 [mu]mol/mol, but we
recommend measuring the actual concentration in the intake air.
[chi]H2Odildry = amount of dilution gas
H2O per mole of dry dilution gas.
[chi]H2Odil = amount of dilution gas
H2O per mole of dilution gas.
[chi][emission]meas = amount of measured
emission in the sample at the respective gas analyzer.
[chi][emission]dry = amount of emission per
dry mole of dry sample.
[chi]H2O[emission]meas = amount of
H2O in sample at emission-detection location. Measure or
estimate these values according to Sec.  1065.145(e)(2).
[chi]H2Oint = amount of H2O in the
intake air, based on a humidity measurement of intake air.
[alpha] = atomic hydrogen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
[beta] = atomic oxygen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
[gamma] = atomic sulfur-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
[delta] = atomic nitrogen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
* * * * *
    (d) Carbon mass fraction and fuel composition. Determine carbon
mass fraction of fuel, wc, and fuel composition represented
by [alpha], [beta], [gamma], and [delta] using one of the following
methods:
    (1) You may calculate wc as described in this paragraph
(d)(1) based on measured fuel properties. To do so, you must determine
values for [alpha] and [beta] in all cases, but you may set [gamma] and
[delta] to zero if the default value listed in Table 1 of this section
is zero. Calculate wc using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.044

Where:

wc = carbon mass fraction of fuel.
MC = molar mass of carbon.
[alpha] = atomic hydrogen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
MH = molar mass of hydrogen.
[beta] = atomic oxygen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
MO = molar mass of oxygen.
[gamma] = atomic sulfur-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
MS = molar mass of sulfur.
[delta] = atomic nitrogen-to-carbon ratio of the mixture of fuel(s)
being combusted, weighted by molar consumption.
MN = molar mass of nitrogen.

[GRAPHIC] [TIFF OMITTED] TR28AP14.045

    (2) Determine a fuel's elemental mass fractions and values for
[alpha], [beta], [gamma], and [delta] as follows:
    (i) For gaseous fuels, use the default values for [alpha], [beta],
[gamma], and [delta] in Table 1 of this section or use good engineering
judgment to determine those values based on measurement.
    (ii) Determine mass fractions of liquid fuels as follows:
    (A) You may determine the carbon and hydrogen mass fractions
according to ASTM D5291 (incorporated by reference in Sec.  1065.1010).
When using ASTM D5291 to determine carbon and hydrogen mass fractions
of gasoline (with or without blended ethanol), use good engineering
judgment to adapt the method as appropriate.
    (B) Determine oxygen mass fraction of gasoline (with or without
blended ethanol) according to ASTM D5599 (incorporated by reference in
Sec.  1065.1010). For all other liquid fuels, determine the oxygen mass
fraction using good engineering judgment.
    (C) Determine the nitrogen mass fraction according to ASTM D4629 or
ASTM D5762 (incorporated by reference in Sec.  1065.1010) for all
liquid fuels. Select the correct method based on the expected nitrogen
content.
    (D) Determine the sulfur mass fraction according to subpart H of
this part.
    (iii) For liquid fuels, use the default values for [alpha], [beta],
[gamma], and [delta] in Table 1 of this section, or you may determine
the value for any of these parameters based on measurement. Calculate
these values using the following equations:
[GRAPHIC] [TIFF OMITTED] TR28AP14.046

Where:

wC = carbon mass fraction of fuel.
wH = hydrogen mass fraction of fuel.
wO = oxygen mass fraction of fuel.
wS = sulfur mass fraction of fuel.
wN = nitrogen mass fraction of fuel.
[GRAPHIC] [TIFF OMITTED] TR28AP14.047

[GRAPHIC] [TIFF OMITTED] TR28AP14.048

   Table 1 of Sec.   1065.655--Default Values of [alpha], [beta], [gamma], [delta], and wc, for Various Fuels
----------------------------------------------------------------------------------------------------------------
                                              Atomic hydrogen, oxygen, sulfur, and nitrogen-to-    Carbon mass
                    Fuel                       carbon ratios  CH[alpha]O[beta]S[gamma]N[delta]  fraction, wc g/g
----------------------------------------------------------------------------------------------------------------
Gasoline....................................  CH1.85O0S0N0....................................             0.866
E10 Gasoline................................  CH1.92O0.03S0N0.................................             0.833
E15 Gasoline................................  CH1.95O0.05S0N0.................................             0.817
E85 Gasoline................................  CH2.73O0.38S0N0.................................             0.576
1 Diesel...........................  CH1.93O0S0N0....................................             0.861
2 Diesel...........................  CH1.80O0S0N0....................................             0.869
Liquefied petroleum gas.....................  CH2.64O0S0N0....................................             0.819
Natural gas.................................  CH3.78 O0.016S0N0...............................             0.747
E100 Ethanol................................  CH3O0.5S0N0.....................................             0.521
M100 Methanol...............................  CH4O1S0N0.......................................             0.375
                                             -------------------------------------------------------------------
Residual fuel blends........................    Must be determined by measured fuel properties as described in
                                                               paragraph (d)(1) of this section.
----------------------------------------------------------------------------------------------------------------

    (e) Calculated raw exhaust molar flow rate from measured intake air
molar flow rate or fuel mass flow rate. You may calculate the raw
exhaust molar flow rate from which you sampled emissions,
nexh, based on the measured intake air molar flow rate,
nint, or the measured fuel mass flow rate, mfuel,
and the values calculated using the chemical balance in paragraph (c)
of this section. The chemical balance must be based on raw exhaust gas
concentrations. Solve for the chemical balance in paragraph (c) of this
section at the same frequency that you update and record or
nint or mfuel. For laboratory tests, calculating
raw exhaust molar flow rate using measured fuel mass flow rate is valid
only for steady-state testing. See Sec.  1065.915(d)(5)(iv) for
application to field testing.
    (1) Crankcase flow rate. If engines are not subject to crankcase
controls under the standard-setting part, you may calculate raw exhaust
flow based on nint or mfuel using one of the
following:
    (i) You may measure flow rate through the crankcase vent and
subtract it from the calculated exhaust flow.
    (ii) You may estimate flow rate through the crankcase vent by
engineering analysis as long as the uncertainty in your calculation
does not adversely affect your ability to show that your engines comply
with applicable emission standards.
    (iii) You may assume your crankcase vent flow rate is zero.

    (2) Intake air molar flow rate calculation. Calculate
nexh based on nint using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.049

Where:

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

Example:

nint = 3.780 mol/s
xint/exhdry = 0.69021 mol/mol
xraw/exhdry = 1.10764 mol/mol
xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR28AP14.050

Where:
nexh = raw exhaust molar flow rate from which you
measured emissions.
mfuel = fuel mass flow rate.

Example:

mfuel = 7.559 g/s
wc = 0.869 g/g
MC = 12.0107 g/mol
xCcombdry = 99.87 mmol/mol = 0.09987 mol/mol
xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR28AP14.051

nexh = 6.066 mol/s

    (f) * * *
    (2) Dilute exhaust and intake air molar flow rate calculation.
Calculate nexh as follows:
[GRAPHIC] [TIFF OMITTED] TR28AP14.052

Example:

nint = 7.930 mol/s
xraw/exhdry = 0.1544 mol/mol
xint/exhdry = 0.1451 mol/mol
xH20/exh = 32.46 mmol/mol = 0.03246 mol/mol
ndexh = 49.02 mol/s
nexh = (0.1544 - 0.1451) [middot] (1 - 0.03246) [middot]
49.02 + 7.930 = 0.4411 + 7.930 = 8.371 mol/s

0
309. Section 1065.659 is amended by revising paragraphs (a) and (d) to
read as follows:

Sec.  1065.659  Removed water correction.

    (a) If you remove water upstream of a concentration measurement, x,
correct for the removed water. Perform this correction based on the
amount of water at the concentration measurement,
xH2O[emission]meas, and at the flow meter,
xH2Oexh, whose flow is used to determine the mass emission
rate or total mass over a test interval. For continuous analyzers
downstream of a sample dryer for transient and ramped-modal cycles, you
must apply this correction on a continuous basis over the test
interval,

even if you use one of the options in Sec.  1065.145(e)(2) that results
in a constant value for xH2O[emission]meas because
xH2Oexh varies over the test interval. For batch analyzers,
determine the flow-weighted average based on the continuous
xH2Oexh values determined as described in paragraph (c) of
this section. For batch analyzers, you may determine the flow-weighted
average xH2Oexh based on a single value of
xH2Oexh determined as described in paragraphs (c)(2) and (3)
of this section, using flow-weighted average or batch concentration
inputs.
* * * * *
    (d) Perform a removed water correction to the concentration
measurement using the following equation:
[GRAPHIC] [TIFF OMITTED] TR28AP14.053

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

Sec.  1065.665  THCE and NMHCE determination.

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

[GRAPHIC] [TIFF OMITTED] TR28AP14.054

Where:

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

    (b) If we require you to determine nonmethane hydrocarbon
equivalent (NMHCE), use the following equation:

xNMHCE = xTHCE - RFCH4[THC-FID]
[middot] xCH4

Eq. 1065.665-4

Where:

xNMHCE = The sum of the C1-equivalent
concentrations of nonoxygenated nonmethane hydrocarbon (NONMHC),
alcohols, and aldehydes.
RFCH4[THC-FID] = response factor of THC-FID to
CH4.
xCH4 = concentration of CH4, HC contamination
(optional) and dry-to-wet corrected, as measured by the gas
chromatograph FID.

    (c) The following example shows how to determine NMHCE emissions
based on ethanol (C2H5OH), methanol
(CH3OH), acetaldehyde (C2H4O), and
formaldehyde (CH2O) as C1-equivalent molar
concentrations:

xTHC[THC-FID]cor = 145.6 [micro]mol/mol
xCH4 = 18.9 [micro]mol/mol
xC2H5OH = 100.8 [micro]mol/mol
xCH3OH = 1.1 [micro]mol/mol
xC2H4O = 19.1 [micro]mol/mol
xCH2O = 1.3 [micro]mol/mol
RFCH4[THC-FID] = 1.07
RFC2H5OH[THC-FID] = 0.76
RFCH3OH[THC-FID] = 0.74
RFH2H4O[THC-FID] = 0.50
RFCH2O[THC-FID] = 0.0

xNMHCE = xTHC[THC-FID]cor -
(xC2H5OH [middot] RFC2H5OH[THC-FID] +
xCH3OH [middot] RFCH3OH[THC-FID] +
xC2H4O [middot] RFC2H4O[THC-FID] +
xCH2O [middot] RFCH2O[THC-FID]) +
xC2H5OH + xCH3OH + xC2H4O +
xCH2O - (RFCH4[THC-FID] [middot]
xCH4)

xNMHCE = 145.6 - (100.8 [middot] 0.76 + 1.1 [middot] 0.74
+ 19.1 [middot] 0.50 + 1.3 [middot] 0) + 100.8 + 1.1 + 19.1 + 1.3 -
(1.07 [middot] 18.9)

xNMHCE = 160.71 [micro]mol/mol

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

Sec.  1065.690  Buoyancy correction for PM sample media.

* * * * *
    (e) Correction calculation. Correct the PM sample media for
buoyancy using the following equations:
[GRAPHIC] [TIFF OMITTED] TR28AP14.055

Where:

mcor = PM mass corrected for buoyancy.
muncor = PM mass uncorrected for buoyancy.
[rho]air = density of air in balance environment.
[rho]weight = density of calibration weight used to span
balance.
[rho]media = density of PM sample media, such as a
filter.
[GRAPHIC] [TIFF OMITTED] TR28AP14.056

Where:

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

[GRAPHIC] [TIFF OMITTED] TR28AP14.057

[GRAPHIC] [TIFF OMITTED] TR28AP14.058

0
312. Section 1065.695 is amended by revising paragraph (c)(4)(i) and
adding paragraph (c)(6)(x) to read as follows:

Sec.  1065.695  Data requirements.

* * * * *
    (c) * * *
    (4) * * *
    (i) Linearity verification.
* * * * *
    (6) * * *
    (x) Number and type of preconditioning cycles.
* * * * *

Subpart H--[Amended]

0
313. Section 1065.701 is amended by revising paragraphs (a), (d), and
(f) to read as follows:

Sec.  1065.701  General requirements for test fuels.

    (a) General. For all emission measurements, use test fuels that
meet the specifications in this subpart, unless the standard-setting
part directs otherwise. Section 1065.10(c)(1) does not apply with
respect to test fuels. Note that the standard-setting parts generally
require that you design your emission controls to function properly
when using commercially available fuels, even if they differ from the
test fuel. Where we specify multiple grades of a certain fuel type
(such as diesel fuel with different sulfur concentrations), see the
standard-setting part to determine which grade to use.
* * * * *
    (d) Fuel specifications. Specifications in this section apply as
follows:
    (1) Measure and calculate values as described in the appropriate
reference procedure. Record and report final values expressed to at
least the same number of decimal places as the applicable limit value.
The right-most digit for each limit value is significant unless
specified otherwise. For example, for a specified distillation
temperature of 60 [deg]C, determine the test fuel's value to at least
the nearest whole number.
    (2) The fuel parameters specified in this subpart depend on
measurement procedures that are incorporated by reference. For any of
these procedures, you may instead rely upon the procedures identified
in 40 CFR part 80 for measuring the same parameter. For example, we may
identify different reference procedures for measuring gasoline
parameters in 40 CFR 80.46.
* * * * *
    (f) Service accumulation and field testing fuels. If we do not
specify a service-accumulation or field-testing fuel in the standard-
setting part, use an appropriate commercially available fuel such as
those meeting minimum specifications from the following table:

              Table 1 of Sec.   1065.701--Examples of Service-Accumulation and Field-Testing Fuels
----------------------------------------------------------------------------------------------------------------
            Fuel category                          Subcategory                    Reference procedure \1\
----------------------------------------------------------------------------------------------------------------
Diesel...............................  Light distillate and light blends   ASTM D975
                                        with residual.
                                       Middle distillate.................  ASTM D6985
                                       Biodiesel (B100)..................  ASTM D6751
Intermediate and residual fuel.......  All...............................  See Sec.   1065.705
Gasoline.............................  Automotive gasoline...............  ASTM D4814
                                       Automotive gasoline with ethanol    ASTM D4814
                                        concentration up to 10 volume %..
Alcohol..............................  Ethanol (E51-83)..................  ASTM D5798
                                       Methanol (M70-M85)................  ASTM D5797
Aviation fuel........................  Aviation gasoline.................  ASTM D910
                                       Gas turbine.......................  ASTM D1655
                                       Jet B wide cut....................  ASTM D6615
Gas turbine fuel.....................  General...........................  ASTM D2880
----------------------------------------------------------------------------------------------------------------
\1\ ASTM specifications are incorporated by reference in Sec.   1065.1010.

0
314. Section 1065.703 is amended by revising paragraph (b),
transferring Table 1 from paragraph (c) to paragraph (b), and revising
Table 1 to read as follows:

Sec.  1065.703  Distillate diesel fuel.

* * * * *

    (b) There are three grades of 2 diesel fuel specified for
use as a test fuel. See the standard-setting part to determine which
grade to use. If the standard-setting part does not specify which grade
to use, use good engineering judgment to select the grade that
represents the fuel on which the engines will operate in use. The three
grades are specified in the following table:

                                     Table 1 of Sec.   1065.703--Test Fuel Specifications for Distillate Diesel Fuel
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Ultra low
                  Property                               Unit                 sulfur     Low sulfur  High sulfur          Reference procedure \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetane Number..............................  --..........................        40-50        40-50        40-50  ASTM D613.
Distillation range:
    Initial boiling point..................  [deg]C......................      171-204      171-204      171-204  ASTM D86.
    10 pct. point..........................  ............................      204-238      204-238      204-238  ASTM D86.
    50 pct. point..........................  ............................      243-282      243-282      243-282  ASTM D86.
    90 pct. point..........................  ............................      293-332      293-332      293-332  ASTM D86.
    Endpoint...............................  ............................      321-366      321-366      321-366  ASTM D86.
Gravity....................................  [deg]API....................        32-37        32-37        32-37  ASTM D4052.
Total sulfur, ultra low sulfur.............  mg/kg.......................         7-15  ...........  ...........  See 40 CFR 80.580.
Total sulfur, low and high sulfur..........  mg/kg.......................  ...........      300-500     800-2500  ASTM D2622 or alternates as allowed
                                                                                under 40 CFR 80.580.
Aromatics, min. (Remainder shall be          g/kg........................          100          100          100  ASTM D5186.
 paraffins, naphthenes, and olefins).
Flashpoint, min............................  [deg]C......................           54           54           54  ASTM D93.
Kinematic Viscosity........................  cSt.........................      2.0-3.2      2.0-3.2      2.0-3.2  ASTM D445.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed procedures.

* * * * *

0
315. Section 1065.705 is revised to read as follows:

Sec.  1065.705  Residual and intermediate residual fuel.

    This section describes the specifications for fuels meeting the
definition of residual fuel in 40 CFR 80.2, including fuels marketed as
intermediate fuel. Residual fuels for service accumulation and any
testing must meet the following specifications:
    (a) The fuel must be a commercially available fuel that is
representative of the fuel that will be used by the engine in actual
use.
    (b) The fuel must be free of used lubricating oil. Demonstrate this
by showing that the fuel meets at least one of the following
specifications.
    (1) Zinc is at or below 15 mg per kg of fuel based on the
procedures specified in IP470, IP501, or ISO 8217 (incorporated by
reference in Sec.  1065.1010).
    (2) Phosphorus is at or below 15 mg per kg of fuel based on the
procedures specified in IP500, IP501, or ISO 8217 (incorporated by
reference in Sec.  1065.1010).
    (3) Calcium is at or below 30 mg per kg of fuel based on the
procedures specified in IP470, IP501, or ISO 8217 (incorporated by
reference in Sec.  1065.1010).
    (c) The fuel must meet the specifications for one of the categories
in the following table:

                             Table 1 of Sec.   1065.705--Service Accumulation and Test Fuel Specifications for Residual Fuel
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Category ISO-F-
          Property                  Unit      ------------------------------------------------------------------------------------------    Reference
                                                RMA 30   RMB 30   RMD 80  RME 180  RMF 180  RMG 380  RMH 380  RMK 380  RMH 700  RMK 700    Procedure\1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density at 15 [deg]C, max...  kg/m\3\........    960.0    975.0    980.0        991.0
                                        991.0            1010.0    991.0   1010.0      ISO
                                                                                3675 or
                                                                                ISO
                                                                                12185
                                                                                (see
                                                                                also
                                                                                ISO
                                                                                8217).
                                              ----------------------------------------------------------------------------------------------------------
Kinematic viscosity at 50     cSt............        30.0           80.0        180.0
 [deg]C, max.
                                        380.0
                                            700.0                    ISO
                                                                   3104.
Flash point, min............  [deg]C.........         60              60         60
                                         60
                                              60                     ISO
                                                                    2719
                                                                    (see
                                                                    also
                                                                     ISO
                                                                  8217).
                                              ----------------------------------------------------------------------------------------------------------
Pour point (upper):
    Winter quality, max.....  [deg]C.........        0       24       30         30
                                         30
                                              30                     ISO
                                                                   3016.
    Summer quality, max.....  ...............        6       24       30         30
                                         30
                                              30
                                              ----------------------------------------------------------------------------------------------------------

Carbon residue, max.........  (kg/kg) %......         10              14       15       20       18       22              22             ISO 10370.
                                              ----------------------------------------------------------------------------------------------------------
Ash, max....................  (kg/kg) %......        0.10           0.10     0.10     0.15        0.15
                                             0.15                    ISO
                                                                   6245.
                                              ----------------------------------------------------------------------------------------------------------
Water, max..................  (m\3\/m\3\) %..         0.5            0.5         0.5
                                         0.5
                                             0.5                     ISO
                                                                   3733.
                                              ----------------------------------------------------------------------------------------------------------
Sulfur, max.................  (kg/kg) %......        3.50           4.00        4.50
                                        4.50
                                             4.50                    ISO
                                                                 8754 or
                                                                     ISO
                                                                   14596
                                                                    (see
                                                                    also
                                                                     ISO
                                                                  8217).
                                              ----------------------------------------------------------------------------------------------------------
Vanadium, max...............  mg/kg..........         150            350      200      500      300      600             600             ISO 14597 or IP
                                                                                501 or IP 470
                                                                                (see also ISO
                                                                                8217).
                                              ----------------------------------------------------------------------------------------------------------
Total sediment potential,     (kg/kg) %......        0.10           0.10        0.10
 max.
                                        0.10
                                             0.10                    ISO
                                                                 10307-2
                                                                    (see
                                                                    also
                                                                     ISO
                                                                  8217).
                                              ----------------------------------------------------------------------------------------------------------
Aluminum plus silicon, max..  mg/kg..........         80              80         80
                                         80
                                              80                     ISO
                                                                   10478
                                                                   or IP
                                                                  501 or
                                                                  IP 470
                                                                    (see
                                                                    also
                                                                     ISO
                                                                 8217:20
                                                                    12).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ISO procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed procedures.

0
316. Section 1065.710 is revised to read as follows:

Sec.  1065.710  Gasoline.

    (a) This section specifies test fuel properties for gasoline with
ethanol (low-level blend only) and for gasoline without ethanol. Note
that the ``fuel type'' for the fuels specified in paragraphs (b) and
(c) of this section is considered to be gasoline. In contrast, fuels
with higher ethanol concentrations, such as fuel containing 82 percent
ethanol, are considered to be ethanol fuels rather than gasoline. We
specify some test fuel parameters that apply uniquely for low-
temperature testing and for testing at altitudes above 1,219 m. For all
other testing, use the test fuel parameters specified for general
testing. Unless the standard-setting part specifies otherwise, use the
fuel specified in paragraph (c) of this section for general testing.
    (b) The following specifications apply for a blended gasoline test
fuel that has nominally 10% ethanol (commonly called E10 test fuel):
    (1) Prepare the blended test fuel from typical refinery gasoline
blending components. You may not use pure compounds, except as follows:
    (i) You may use neat ethanol as a blendstock.
    (ii) You may adjust the test fuel's vapor pressure by adding
butane.
    (iii) You may adjust the test fuel's benzene content by adding
benzene.
    (iv) You may adjust the test fuel's sulfur content by adding sulfur
compounds that are representative of those found with in-use fuels.
    (2) Table 1 of this section identifies limit values consistent with
the units in the reference procedure for each fuel property. These
values are generally specified in international units. Values presented
in parentheses are for information only. Table 1 follows:

                               Table 1 of Sec.   1065.710--Test Fuel Specifications for a Low-Level Ethanol-Gasoline Blend
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Specification
                                                         ----------------------------------------------------------------
             Property                       Unit                                  Low-temperature       High altitude         Reference procedure \1\
                                                             General testing          testing              testing
--------------------------------------------------------------------------------------------------------------------------------------------------------
Antiknock Index (R+M)/2..........  .....................                87.0--88.4 \2\               87.0 Minimum.......  ASTM D2699 and D2700.
                                                         ----------------------------------------------------------------
Sensitivity (R-M)................  .....................                            7.5 Minimum                           ASTM D2699 and D2700.
                                                         ----------------------------------------------------------------
Dry Vapor Pressure Equivalent      kPa (psi)............  60.0-63.4...........  77.2-81.4..........  52.4-55.2..........  ASTM D5191.
 (DVPE) \3,4\.                                            (8.7-9.2)...........  (11.2-11.8)........  (7.6-8.0)..........
Distillation \4\.................  [deg]C ([deg]F)......  49-60...............  43-54..............  49-60..............  ASTM D86.
10% evaporated...................                         (120-140)...........  (110-130)..........  (120-140)..........
                                                         ----------------------------------------------------------------

50% evaporated...................  [deg]C ([deg]F)......                         88-99 (190-210).
90% evaporated...................  [deg]C ([deg]F)......                        157-168 (315-335).
Evaporated final boiling point...  [deg]C ([deg]F)......                        193-216 (380-420).
Residue..........................  milliliter...........                           2.0 Maximum.
Total Aromatic Hydrocarbons......  volume %.............                             21.0-25.0                            ASTM D5769.
C6 Aromatics (benzene)...........  volume %.............                             0.5-0.7.
C7 Aromatics (toluene)...........  volume %.............                             5.2-6.4.
C8 Aromatics.....................  volume %.............                             5.2-6.4.
C9 Aromatics.....................  volume %.............                             5.2-6.4.
C10+ Aromatics...................  volume %.............                             4.4-5.6.
Olefins \5\......................  mass %...............                             4.0-10.0                             ASTM D6550.
Ethanol blended..................  volume %.............                             9.6-10.0                             See paragraph (b)(3) of this
                                                                                section.
Ethanol confirmatory \6\.........  volume %.............                             9.4-10.2                             ASTM D4815 or D5599.
Total Content of Oxygenates Other  volume %.............                            0.1 Maximum                           ASTM D4815 or D5599.
 than Ethanol \6\.
Sulfur...........................  mg/kg................                             8.0-11.0                             ASTM D2622, D5453 or D7039.
Lead.............................  g/liter..............                          0.0026 Maximum                          ASTM D3237.
Phosphorus.......................  g/liter..............                          0.0013 Maximum                          ASTM D3231.
Copper Corrosion.................  .....................                           No. 1 Maximum                          ASTM D130.
Solvent-Washed Gum Content.......  mg/100 milliliter....                            3.0 Maximum                           ASTM D381.
Oxidation Stability..............  minute...............                           1000 Minimum                           ASTM D525.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed procedures.
\2\ Octane specifications apply only for testing related to exhaust emissions. For engines or vehicles that require the use of premium fuel, as
  described in paragraph (d) of this section, the adjusted specification for antiknock index is a minimum value of 91.0; no maximum value applies. All
  other specifications apply for this high-octane fuel.
\3\ Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, using the following equation: DVPE (kPa) =
  0.956[middot]pT--2.39 or DVPE (psi) = 0.956[middot]pT--0.347. DVPE is intended to be equivalent to Reid Vapor Pressure using a different test method.
\4\ Parenthetical values are shown for informational purposes only.
\5\ The reference procedure prescribes measurement of olefin concentration in mass %. Multiply this result by 0.857 and round to the first decimal place
  to determine the olefin concentration in volume %.
\6\ ASTM D5599 prescribes concentration measurements for ethanol and other oxygenates in mass %. Convert results to volume % as specified in Section
  14.3 of ASTM D4815.

    (3) The ethanol-blended specification in Table 1 of this section is
based on the volume % ethanol content of the fuel as determined during
blending by the fuel supplier and as stated by the supplier at the time
of fuel delivery. Use good engineering judgment to determine the volume
% of ethanol based on the volume of each blendstock. We recommend using
a flow-based or gravimetric procedure that has an accuracy and
repeatability of  0.1%.
    (c) The specifications of this paragraph (c) apply for testing with
neat gasoline. This is sometimes called indolene or E0 test fuel.
Gasoline for testing must have octane values that represent
commercially available fuels for the appropriate application. Test fuel
specifications apply as follows:

                   Table 2 of Sec.   1065.710--Test Fuel Specifications for Neat (E0) Gasoline
----------------------------------------------------------------------------------------------------------------
                                                            Specification
                                                ------------------------------------
           Property                  Unit                           Low-temperature    Reference procedure \1\
                                                  General testing       testing
----------------------------------------------------------------------------------------------------------------
Distillation Range:
    Evaporated initial         [deg]C..........  24-35 \2\.......  24-36...........  ASTM D86.
     boiling point.
        10% evaporated.......  ................  49-57...........  37-48...........
        50% evaporated.......  ................  93-110..........  82-101..........
        90% evaporated.......  ................  149-163.........  158-174.........
    Evaporated final boiling   ................  Maximum, 213....  Maximum, 212....
     point.
Hydrocarbon composition:
    Olefins..................  volume %........  Maximum, 0.10...  Maximum, 0.175..  ASTM D1319.
    Aromatics................  ................  Maximum, 0.35...  Maximum, 0.304..
    Saturates................  ................  Remainder.......  Remainder.......
Lead.........................  g/liter.........  Maximum, 0.013..  Maximum, 0.013..  ASTM D3237.
Phosphorous..................  g/liter.........  Maximum, 0.0013.  Maximum, 0.005..  ASTM D3231.
Total sulfur.................  mg/kg...........  Maximum, 80.....  Maximum, 80.....  ASTM D2622.
Dry vapor pressure equivalent  kPa.............  60.0-63.4 \2,4\.  77.2-81.4.......  ASTM D5191.
 \3\.
----------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed
  procedures.

\2\ For testing at altitudes above 1219 m, the specified initial boiling point range is (23.9 to 40.6) [deg]C
  and the specified volatility range is (52.0 to 55.2) kPa.
\3\ Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, in kPa using
  the following equation: DVPE (kPa) = 0.956[middot]pT-2.39 or DVPE (psi) = 0.956[middot]pT-0.347. DVPE is
  intended to be equivalent to Reid Vapor Pressure using a different test method.
\4\ For testing unrelated to evaporative emissions, the specified range is (55.2 to 63.4) kPa.

    (d) Use the high-octane gasoline specified in paragraph (b) of this
section only for engines or vehicles for which the manufacturer
conditions the warranty on the use of premium gasoline.

0
317. Section 1065.715 is amended by revising paragraph (a) to read as
follows:

Sec.  1065.715  Natural gas.

    (a) Except as specified in paragraph (b) of this section, natural
gas for testing must meet the specifications in the following table:

  Table 1 of Sec.   1065.715--Test Fuel Specifications for Natural Gas
------------------------------------------------------------------------
            Property                             Value \1\
------------------------------------------------------------------------
Methane, CH4....................  Minimum, 0.87 mol/mol.
Ethane, C2H6....................  Maximum, 0.055 mol/mol.
Propane, C3H8...................  Maximum, 0.012 mol/mol.
Butane, C4H10...................  Maximum, 0.0035 mol/mol.
Pentane, C5H12..................  Maximum, 0.0013 mol/mol.
C6 and higher...................  Maximum, 0.001 mol/mol.
Oxygen..........................  Maximum, 0.001 mol/mol.
Inert gases (sum of CO2 and N2).  Maximum, 0.051 mol/mol.
------------------------------------------------------------------------
\1\ Demonstrate compliance with fuel specifications based on the
  reference procedures in ASTM D1945 (incorporated by reference in Sec.
   1065.1010), or on other measurement procedures using good engineering
  judgment. See Sec.   1065.701(d) for other allowed procedures.

* * * * *

0
318. Section 1065.720 is amended by revising paragraph (a) to read as
follows:

Sec.  1065.720  Liquefied petroleum gas.

    (a) Except as specified in paragraph (b) of this section, liquefied
petroleum gas for testing must meet the specifications in the following
table:

                Table 1 of Sec.   1065.720--Test Fuel Specifications for Liquefied Petroleum Gas
----------------------------------------------------------------------------------------------------------------
                 Property                              Value                     Reference procedure \1\
----------------------------------------------------------------------------------------------------------------
Propane, C3H8............................  Minimum, 0.85 m\3\/m\3\.....  ASTM D2163.
Vapor pressure at 38 [deg]C..............  Maximum, 1400 kPa...........  ASTM D1267or D2598.\2\
Volatility residue (evaporated             Maximum, -38 [deg]C.........  ASTM D1837.
 temperature, 35 [deg]C).
Butanes..................................  Maximum, 0.05 m\3\/m\3\.....  ASTM D2163.
Butenes..................................  Maximum, 0.02 m\3\/m\3\.....  ASTM D2163.
Pentenes and heavier.....................  Maximum, 0.005 m\3\/m\3\....  ASTM D2163.
Propene..................................  Maximum, 0.1 m\3\/m\3\......  ASTM D2163.
Residual matter (residue on evaporation    Maximum, 0.05 ml pass\3\....  ASTM D2158.
 of 100 ml oil stain observation).
Corrosion, copper strip..................  Maximum, No. 1..............  ASTM D1838.
Sulfur...................................  Maximum, 80 mg/kg...........  ASTM D2784.
Moisture content.........................  pass........................  ASTM D2713.
----------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed
  procedures.
\2\ If these two test methods yield different results, use the results from ASTM D1267.
\3\ The test fuel must not yield a persistent oil ring when you add 0.3 ml of solvent residue mixture to a
  filter paper in 0.1 ml increments and examine it in daylight after two minutes.

* * * * *

0
319. A new Sec.  1065.725 is added to subpart H to read as follows:

Sec.  1065.725  High-level ethanol-gasoline blends.

    For testing vehicles capable of operating on a high-level ethanol-
gasoline blend, create a test fuel as follows:
    (a) Add ethanol to an E10 fuel meeting the specifications described
in Sec.  1065.710 until the ethanol content of the blended fuel is
between 80 and 83 volume %.
    (b) You may alternatively add ethanol to a gasoline base fuel with
no ethanol if you can demonstrate that such a base fuel blended with
the proper amount of ethanol would meet all the specifications for E10
test fuel described in Sec.  1065.710, other than the ethanol content.
    (c) The ethanol used for blending must be either denatured ethanol
meeting the specifications in 40 CFR 80.1610, or fuel-grade ethanol
with no denaturant. Account for the volume of any denaturant when
calculating volumetric percentages.
    (d) The blended test fuel must have a dry vapor pressure equivalent
between 41.5 and 45.1 kPa (6.0 and 6.5 psi) when measured using the
procedure specified in Sec.  1065.710. You may add commercial grade
butane as needed to meet this specification.

0
320. Section 1065.750 is amended by revising the introductory text and
paragraph (a) to read as follows:

Sec.  1065.750  Analytical gases.

    Analytical gases must meet the accuracy and purity specifications
of this section, unless you can show that other specifications would
not affect your ability to show that you comply with all applicable
emission standards.
    (a) Subparts C, D, F, and J of this part refer to the following gas
specifications:
    (1) Use purified gases to zero measurement instruments and to blend

with calibration gases. Use gases with contamination no higher than the
highest of the following values in the gas cylinder or at the outlet of
a zero-gas generator:
    (i) 2% contamination, measured relative to the flow-weighted mean
concentration expected at the standard. For example, if you would
expect a flow-weighted CO concentration of 100.0 [mu]mol/mol, then you
would be allowed to use a zero gas with CO contamination less than or
equal to 2.000 [mu]mol/mol.
    (ii) Contamination as specified in the following table:

                    Table 1 of Sec.   1065.750--General Specifications for Purified Gases \1\
----------------------------------------------------------------------------------------------------------------
               Constituent                           Purified air                        Purified N2
----------------------------------------------------------------------------------------------------------------
THC (C1-equivalent)......................  <= 0.05 [mu]mol/mol.............  <= 0.05 [mu]mol/mol.
CO.......................................  <= 1 [mu]mol/mol................  <= 1 [mu]mol/mol.
CO2......................................  <= 10 [mu]mol/mol...............  <= 10 [mu]mol/mol.
O2.......................................  0.205 to 0.215 mol/mol..........  <= 2 [mu]mol/mol.
NOX......................................  <= 0.02 [mu]mol/mol.............  <= 0.02 [mu]mol/mol.
N2O\2\...................................  <= 0.02 [mu]mol/mol.............  <= 0.02 [mu]mol/mol.
----------------------------------------------------------------------------------------------------------------
\1\ We do not require these levels of purity to be NIST-traceable.
\2\ The N2O limit applies only if the standard-setting part requires you to report N2O or certify to an N2O
  standard.

    (2) Use the following gases with a FID analyzer:
    (i) FID fuel. Use FID fuel with a stated H2
concentration of (0.39 to 0.41) mol/mol, balance He or N2,
and a stated total hydrocarbon concentration of 0.05 [mu]mol/mol or
less. For GC-FIDs that measure methane (CH4) using a FID
fuel that is balance N2, perform the CH4
measurement as described in SAE J1151 (incorporated by reference in
Sec.  1065.1010).
    (ii) FID burner air. Use FID burner air that meets the
specifications of purified air in paragraph (a)(1) of this section. For
field testing, you may use ambient air.
    (iii) FID zero gas. Zero flame-ionization detectors with purified
gas that meets the specifications in paragraph (a)(1) of this section,
except that the purified gas O2 concentration may be any
value. Note that FID zero balance gases may be any combination of
purified air and purified nitrogen. We recommend FID analyzer zero
gases that contain approximately the expected flow-weighted mean
concentration of O2 in the exhaust sample during testing.
    (iv) FID propane span gas. Span and calibrate THC FID with span
concentrations of propane, C3H8. Calibrate on a
carbon number basis of one (C1). For example, if you use a
C3H8 span gas of concentration 200 [mu]mol/mol,
span a FID to respond with a value of 600 [mu]mol/mol. Note that FID
span balance gases may be any combination of purified air and purified
nitrogen. We recommend FID analyzer span gases that contain
approximately the flow-weighted mean concentration of O2
expected during testing. If the expected O2 concentration in
the exhaust sample is zero, we recommend using a balance gas of
purified nitrogen.
    (v) FID CH4 span gas. If you always span and calibrate a
CH4 FID with a nonmethane cutter, then span and calibrate
the FID with span concentrations of CH4. Calibrate on a
carbon number basis of one (C1). For example, if you use a
CH4 span gas of concentration 200 [mu]mol/mol, span a FID to
respond with a value of 200 [mu]mol/mol. Note that FID span balance
gases may be any combination of purified air and purified nitrogen. We
recommend FID analyzer span gases that contain approximately the
expected flow-weighted mean concentration of O2 in the
exhaust sample during testing. If the expected O2
concentration in the exhaust sample is zero, we recommend using a
balance gas of purified nitrogen.
    (3) Use the following gas mixtures, with gases traceable within
1% of the NIST-accepted value or other gas standards we
approve:
    (i) CH4, balance purified air and/or N2 (as
applicable).
    (ii) C2H6, balance purified air and/or
N2 (as applicable).
    (iii) C3H8, balance purified air and/or
N2 (as applicable).
    (iv) CO, balance purified N2.
    (v) CO2, balance purified N2.
    (vi) NO, balance purified N2.
    (vii) NO2, balance purified air.
    (viii) O2, balance purified N2.
    (ix) C3H8, CO, CO2, NO, balance
purified N2.
    (x) C3H8, CH4, CO, CO2,
NO, balance purified N2.
    (xi) N2O, balance purified air and/or N2 (as
applicable).
    (4) You may use gases for species other than those listed in
paragraph (a)(3) of this section (such as methanol in air, which you
may use to determine response factors), as long as they are traceable
to within 3% of the NIST-accepted value or other similar
standards we approve, and meet the stability requirements of paragraph
(b) of this section.
    (5) You may generate your own calibration gases using a precision
blending device, such as a gas divider, to dilute gases with purified
N2 or purified air. If your gas divider meets the
specifications in Sec.  1065.248, and the gases being blended meet the
requirements of paragraphs (a)(1) and (3) of this section, the
resulting blends are considered to meet the requirements of this
paragraph (a).
* * * * *

Subpart I--[Amended]

0
321. Section 1065.805 is amended by revising paragraphs (d) and (f) to
read as follows:

Sec.  1065.805  Sampling system.

* * * * *
    (d) You may bubble a sample of the exhaust through water to collect
alcohols for later analysis. You may also use a photoacoustic analyzer
to quantify ethanol and methanol in an exhaust sample as described in
Sec.  1065.269.
* * * * *
    (f) You may sample alcohols or carbonyls using ``California Non-
Methane Organic Gas Test Procedures'' (incorporated by reference in
Sec.  1065.1010). If you use this method, follow its calculations to
determine the mass of the alcohol/carbonyl in the exhaust sample, but
follow subpart G of this part for all other calculations (40 CFR part
1066, subpart G, for vehicle testing).
* * * * *

0
322. Section 1065.845 is revised to read as follows:

Sec.  1065.845  Response factor determination.

    Since FID analyzers generally have an incomplete response to
alcohols and carbonyls, determine each FID analyzer's alcohol/carbonyl
response factor (RFOHCi[THC-FID]) after FID optimization to
subtract those responses from the FID reading. Use the most

recently determined alcohol/carbonyl response factors to compensate for
alcohol/carbonyl response. You are not required to determine the
response factor for a compound unless you will subtract its response to
compensate for a response.
    (a) You may generate response factors as described in paragraph (b)
of this section, or you may use the following default response factors,
consistent with good engineering judgment:

 Table 1 of Sec.   1065.845--Default Values for THC FID Response Factor
              Relative to Propane on a C+1-Equivalent Basis
------------------------------------------------------------------------
                                                         Response factor
                        Compound                               (RF)
------------------------------------------------------------------------
acetaldehyde...........................................             0.50
ethanol................................................             0.75
formaldehyde...........................................             0.00
methanol...............................................             0.63
propanol...............................................             0.85
------------------------------------------------------------------------

    (b) Determine the alcohol/carbonyl response factors as follows:
    (1) Select a C3H8 span gas that meets the
specifications of Sec.  1065.750. Note that FID zero and span balance
gases may be any combination of purified air or purified nitrogen that
meets the specifications of Sec.  1065.750. We recommend FID analyzer
zero and span gases that contain approximately the flow-weighted mean
concentration of O2 expected during testing. Record the
C3H8 concentration of the gas.
    (2) Select or prepare an alcohol/carbonyl calibration gas that
meets the specifications of Sec.  1065.750 and has a concentration
typical of the peak concentration expected at the hydrocarbon standard.
Record the calibration concentration of the gas.
    (3) Start and operate the FID analyzer according to the
manufacturer's instructions.
    (4) Confirm that the FID analyzer has been calibrated using
C3H8. Calibrate on a carbon number basis of one
(C1). For example, if you use a C3H8
span gas of concentration 200 [mu]mol/mol, span the FID to respond with
a value of 600 [mu]mol/mol.
    (5) Zero the FID. Note that FID zero and span balance gases may be
any combination of purified air or purified nitrogen that meets the
specifications of Sec.  1065.750. We recommend FID analyzer zero and
span gases that contain approximately the flow-weighted mean
concentration of O2 expected during testing.
    (6) Span the FID with the C3H8 span gas that
you selected under paragraph (a)(1) of this section.
    (7) Introduce at the inlet of the FID analyzer the alcohol/carbonyl
calibration gas that you selected under paragraph (a)(2) of this
section.
    (8) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the analyzer and to
account for its response.
    (9) While the analyzer measures the alcohol/carbonyl concentration,
record 30 seconds of sampled data. Calculate the arithmetic mean of
these values.
    (10) Divide the mean measured concentration by the recorded span
concentration of the alcohol/carbonyl calibration gas on a
C1-equivalent basis. The result is the FID analyzer's
response factor for alcohol/carbonyl, RFOHCi[THC-FID] on a
C1-equivalent basis.
    (c) Alcohol/carbonyl calibration gases must remain within 2% of the labeled concentration. You must demonstrate the
stability based on a quarterly measurement procedure with a precision
of 2% percent or another method that we approve. Your
measurement procedure may incorporate multiple measurements. If the
true concentration of the gas changes deviates by more than 2%, but less than 10%, the gas may be relabeled with
the new concentration.

0
323. Section 1065.850 is revised to read as follows:

Sec.  1065.850  Calculations.

    Use the calculations specified in Sec.  1065.665 to determine THCE
or NMHCE and the calculations specified in 40 CFR 1066.635 to determine
NMOG.

Subpart J--[Amended]

0
324. Section 1065.905 is amended by revising paragraphs (a) and
(d)(2)(i)(A) to read as follows:

Sec.  1065.905  General provisions.

    (a) General. Unless the standard-setting part specifies deviations
from the provisions of this subpart, field testing and laboratory
testing with PEMS must conform to the provisions of this subpart. Use
good engineering judgment when testing with PEMS to ensure proper
function of the instruments under test conditions. For example, this
may require additional maintenance or calibration for field testing or
may require verification after moving the PEMS unit.
* * * * *
    (d) * * *
    (2) * * *
    (i) * * *
    (A) Use good engineering judgment to control dilution air
temperature. If you choose to directly and actively control dilution
air temperature, set the temperature to 25 [deg]C.
* * * * *

0
325. Section 1065.915 is amended by revising paragraph (a) to read as
follows:

Sec.  1065.915  PEMS instruments.

    (a) Instrument specifications. We recommend that you use PEMS that
meet the specifications of subpart C of this part. For unrestricted use
of PEMS in a laboratory or similar environment, use a PEMS that meets
the same specifications as each lab instrument it replaces. For field
testing or for testing with PEMS in a laboratory or similar
environment, under the provisions of Sec.  1065.905(b), the
specifications in the following table apply instead of the
specifications in Table 1 of Sec.  1065.205.

                                 Table 1 of Sec.   1065.915--Recommended Minimum PEMS Measurement Instrument Performance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Rise time,
                                    Measured quantity    t10	90, and    Recording update
           Measurement                   symbol          fall time,         frequency         Accuracy \1\      Repeatability \1\        Noise \1\
                                                           t90	10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine speed transducer..........  fn................             1 s  1 Hz means........  5% of pt. or 1% of  2% of pt. or 1% of  0.5% of max.
                                                                                max.                max.
Engine torque estimator, BSFC      T or BSFC.........             1 s  1 Hz means........  8% of pt. or 5% of  2% of pt. or 1% of  1% of max.
 (This is a signal from an                                                                  max.                max.
 engine's ECM).
General pressure transducer (not   p.................             5 s  1 Hz..............  5% of pt. or 5% of  2% of pt. or 0.5%   1% of max.
 a part of another instrument).                                                             max.                of max.
Atmospheric pressure meter.......  patmos............            50 s  0.1 Hz............  250 Pa............  200 Pa............  100 Pa.
General temperature sensor (not a  T.................             5 s  1 Hz..............  1% of pt. K or 5 K  0.5% of pt. K or 2  0.5% of max 0.5 K.
 part of another instrument).                                                                                K.

General dewpoint sensor..........  Tdew..............            50 s  0.1 Hz............  3 K...............  1 K...............  1 K.
Exhaust flow meter...............  nb................             1 s  1 Hz means........  5% of pt. or 3% of  2% of pt..........  2% of max.
                                                                                max.
Dilution air, inlet air, exhaust,  nb................             1 s  1 Hz means........  2.5% of pt. or      1.25% of pt. or     1% of max.
 and sample flow meters.                                                                    1.5% of max.        0.75% of max.
Continuous gas analyzer..........  x.................             5 s  1 Hz..............  4% of pt. or 4% of  2% of pt. or 2% of  1% of max.
                                                                                meas.               meas.
Gravimetric PM balance...........  mPM...............  ..............  ..................  See Sec.            0.5 [mu]g.........
                                                                                1065.790.
Inertial PM balance..............  mPM...............  ..............  ..................  4% of pt. or 4% of  2% of pt. or 2% of  1% of max.
                                                                                meas.               meas.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Accuracy, repeatability, and noise are all determined with the same collected data, as described in Sec.   1065.305, and based on absolute values.
  ``pt.'' refers to the overall flow-weighted mean value expected at the standard; ``max.'' refers to the peak value expected at the standard over any
  test interval, not the maximum of the instrument's range; ``meas'' refers to the actual flow-weighted mean measured over any test interval.

* * * * *

0
326. Section 1065.920 is amended by revising paragraphs (a), (b)
introductory text, and (b)(7) introductory text to read as follows:

Sec.  1065.920  PEMS calibrations and verifications.

    (a) Subsystem calibrations and verifications. Use all the
applicable calibrations and verifications in subpart D of this part,
including the linearity verifications in Sec.  1065.307, to calibrate
and verify PEMS. Note that a PEMS does not have to meet the system-
response and updating-recording verifications of Sec.  1065.308 and
Sec.  1065.309 if it meets the overall verification described in
paragraph (b) of this section or if it measures PM using any method
other than that described in Sec.  1065.170(c)(1). This section does
not apply to ECM signals. Note that because the regulations of this
part require you to use good engineering judgment, it may be necessary
to perform additional verifications and analysis. It may also be
necessary to limit the range of conditions under which the PEMS can be
used or to include specific additional maintenance to ensure that it
functions properly under the test conditions. As provided in 40 CFR
1068.5, we will deem your system to not meet the requirements of this
section if we determine that you did not use good engineering judgment
to verify the measurement equipment. We may also deem your system to
meet these requirements only under certain test conditions. If we ask
for it, you must send us a summary of your verifications. We may also
ask you to provide additional information or analysis to support your
conclusions.
    (b) Overall verification. This paragraph (b) specifies methods and
criteria for verifying the overall performance of systems not fully
compliant with requirements that apply for laboratory testing. Maintain
records to show that the particular make, model, and configuration of
your PEMS meets this verification. You may rely on data and other
information from the PEMS manufacturer. However, we recommend that you
generate your own records to show that your specific PEMS meets this
verification. If you upgrade or change the configuration of your PEMS,
your record must show that your new configuration meets this
verification. The verification required by this section consists of
operating an engine over a duty cycle in the laboratory and
statistically comparing data generated and recorded by the PEMS with
data simultaneously generated and recorded by laboratory equipment as
follows:
* * * * *
    (7) The PEMS passes the verification of this paragraph (b) if any
one of the following are true for each constituent:
* * * * *

Subpart K--[Amended]

0
327. Section 1065.1001 is amended as follows:
0
a. By removing the definition for ``C1 equivalent (or
basis)''.
0
b. By adding a definition for ``C1-equivalent (or basis)''
in alphabetical order.
0
c. By removing the definition for ``Engine''.
0
d. By revising the definitions for ``HEPA filter'', ``Hydrocarbon
(HC)'', ``Oxygenated fuels'', and ``Precision''.
0
e. By adding a definition for ``Purified air'' in alphabetical order.

Sec.  1065.1001  Definitions.

* * * * *
    C1-equivalent (or basis) means a convention of expressing HC
concentrations based on the total number of carbon atoms present, such
that the C1 equivalent of a molar HC concentration equals
the molar concentration multiplied by the mean number of carbon atoms
in each HC molecule. For example, the C1 equivalent of 10
[mu]mol/mol of propane (C3H8) is 30 [mu]mol/mol.
C1 equivalent molar values may be denoted as ``ppmC'' in the
standard-setting part. Molar mass may also be expressed on a
C1 basis. Note that calculating HC masses from molar
concentrations and molar masses is only valid where they are each
expressed on the same carbon basis.
* * * * *
    HEPA filter means high-efficiency particulate air filters that are
rated to achieve a minimum initial particle-removal efficiency of
99.97% using ASTM F1471 (incorporated by reference in Sec.  1065.1010).
* * * * *
    Hydrocarbon (HC) means THC, THCE, NMHC, NMOG, or NMHCE, as
applicable. Hydrocarbon generally means the hydrocarbon group on which
the emission standards are based for each type of fuel and engine.
* * * * *
    Oxygenated fuels means fuels composed of at least 25% oxygen-
containing compounds, such as ethanol or methanol. Testing engines that
use oxygenated fuels generally requires the use of the sampling methods
in subpart I of this part. However, you should read the standard-
setting part and subpart I

of this part to determine appropriate sampling methods.
* * * * *
    Precision means two times the standard deviation of a set of
measured values of a single zero or reference quantity. See also the
related definitions of noise and repeatability in this section.
* * * * *
    Purified air means air meeting the specifications for purified air
in Sec.  1065.750. Purified air may be produced by purifying ambient
air. The purification may occur at the test site or at another location
(such as at a gas supplier's facility). Alternatively, purified air may
be synthetically generated, using good engineering judgment, from
purified oxygen and nitrogen. The addition of other elements normally
present in purified ambient air (such as Ar) is not required.
* * * * *

0
328. Section 1065.1005 is revised to read as follows:

Sec.  1065.1005  Symbols, abbreviations, acronyms, and units of
measure.

    The procedures in this part generally follow the International
System of Units (SI), as detailed in NIST Special Publication 811,
which we incorporate by reference in Sec.  1065.1010. See Sec.  1065.20
for specific provisions related to these conventions. This section
summarizes the way we use symbols, units of measure, and other
abbreviations.
    (a) Symbols for quantities. This part uses the following symbols
and units of measure for various quantities:

--------------------------------------------------------------------------------------------------------------------------------------------------------
       Symbol                      Quantity                           Unit                    Unit symbol            Units in terms of SI base units
--------------------------------------------------------------------------------------------------------------------------------------------------------
[alpha]............  atomic hydrogen-to-carbon ratio.....  mole per mole.............  mol/mol.................  1
A..................  area................................  square meter..............  m\2\....................  m\2\
a0.................  intercept of least squares
                      regression.
a1.................  slope of least squares regression...
ag.................  acceleration of Earth's gravity.....  meter per square second...  m/s\2\..................  m/s\2\
[beta].............  ratio of diameters..................  meter per meter...........  m/m.....................  1
[beta].............  atomic oxygen-to-carbon ratio.......  mole per mole.............  mol/mol.................  1
C#.................  number of carbon atoms in a molecule
Cd.................  discharge coefficient...............
Cf.................  flow coefficient....................
[delta]............  atomic nitrogen-to-carbon ratio.....  mole per mole.............  mol/mol.................  1
d..................  Diameter............................  meter.....................  m.......................  m
DR.................  dilution ratio......................  mole per mole.............  mol/mol.................  1
[epsi].............  error between a quantity and its
                      reference.
e..................  brake-specific emission or fuel       gram per kilowatt hour....  g/(kW[middot]hr)........  g[middot]3.6-1[middot]10\6\[middot]m-
                      consumption.                                                                                2[middot]kg[middot]s\2\
F..................  F-test statistic....................
f..................  frequency...........................  hertz.....................  Hz......................  s-1
fn.................  angular speed (shaft)...............  revolutions per minute....  r/min...................  2[middot][pi][middot]60-
                                                                                1[middot]m[middot]m-1[middot]s-1
[gamma]............  ratio of specific heats.............  (joule per kilogram         (J/(kg[middot]K))/(J/     1
                                                            kelvin) per (joule per      (kg[middot]K)).
                                                            kilogram kelvin).
[gamma]............  atomic sulfur-to-carbon ratio.......  mole per mole.............  mol/mol.................  1
K..................  correction factor...................  ..........................  ........................  1
Kv.................  calibration coefficient.............  ..........................  m\4\[middot]s[middot]K\0  m\4\[middot]s[middot]K\0.5\[middot]kg-1
                                                                                .5\/kg.
l..................  length..............................  meter.....................  m.......................  m
[mu]...............  viscosity, dynamic..................  pascal second.............  Pa[middot]s.............  m-1[middot]kg[middot]s-1
M..................  molar mass\1\.......................  gram per mole.............  g/mol...................  10-3[middot]kg[middot]mol-1
m..................  mass................................  kilogram..................  kg......................  kg
m..................  mass rate...........................  kilogram per second.......  kg/s....................  kg[middot]s-1
[nu]...............  viscosity, kinematic................  meter squared per second..  m\2\/s..................  m\2\[middot]s-1
N..................  total number in series..............
n..................  amount of substance.................  mole......................  mol.....................  mol
n..................  amount of substance rate............  mole per second...........  mol/s...................  mol[middot]s-1
P..................  power...............................  kilowatt..................  kW......................  10\3\[middot]m\2\[middot]kg[middot]s-3
PF.................  penetration fraction................
p..................  pressure............................  pascal....................  Pa......................  m-1[middot]kg[middot]s-2
[rho]..............  mass density........................  kilogram per cubic meter..  kg/m\3\.................  kg[middot]m-3
[Delta]p...........  differential static pressure........  pascal....................  Pa......................  m-1[middot]kg[middot]s-2
r..................  ratio of pressures..................  pascal per pascal.........  Pa/Pa...................  1
r\2\...............  coefficient of determination........
Ra.................  average surface roughness...........  micrometer................  [mu]m...................  10-6 m
Re#................  Reynolds number.....................
RF.................  response factor.....................
RH.................  relative humidity...................
[sigma]............  non-biased standard deviation.......
S..................  Sutherland constant.................  kelvin....................  K.......................  K
SEE................  standard estimate of error..........
T..................  absolute temperature................  kelvin....................  K.......................  K
T..................  Celsius temperature.................  degree Celsius............  [deg]C..................  K - 273.15
T..................  torque (moment of force)............  newton meter..............  N[middot]m..............  m\2\[middot]kg[middot]s-2
[thgr].............  plane angle.........................  degrees...................  [deg]...................  rad
t..................  time................................  second....................  s.......................  s
[Delta]t...........  time interval, period, 1/frequency..  second....................  s.......................  s
V..................  volume..............................  cubic meter...............  m\3\....................  m\3\
V..................  volume rate.........................  cubic meter per second....  m\3\/s..................  m\3\[middot]s-1

W..................  work................................  kilowatt hour.............  kW[middot]hr............  3.6[middot]10-
                                                                                6[middot]m\2\[middot]kg[middot]s-2
wc.................  carbon mass fraction................  gram per gram.............  g/g.....................  1
x..................  amount of substance mole fraction     mole per mole.............  mol/mol.................  1
                      \2\.
x..................  flow-weighted mean concentration....  mole per mole.............  mol/mol.................  1
y..................  generic variable....................
Z..................  compressibility factor..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ See paragraph (f)(2) of this section for the values to use for molar masses. Note that in the cases of NOX and HC, the regulations specify effective
  molar masses based on assumed speciation rather than actual speciation.
\2\ Note that mole fractions for THC, THCE, NMHC, NMHCE, and NOTHC are expressed on a C1 equivalent basis.

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

------------------------------------------------------------------------
              Symbol                               Species
------------------------------------------------------------------------
Ar................................  argon.
C.................................  carbon.
CH2O..............................  formaldehyde.
CH3OH.............................  methanol.
CH4...............................  methane.
C2H4O.............................  acetaldehyde.
C2H5OH............................  ethanol.
C2H6..............................  ethane.
C3H7OH............................  propanol.
C3H8..............................  propane.
C4H10.............................  butane.
C5H12.............................  pentane.
CO................................  carbon monoxide.
CO2...............................  carbon dioxide.
H.................................  atomic hydrogen.
H2................................  molecular hydrogen.
H2O...............................  water.
H2SO4.............................  sulfuric acid.
HC................................  hydrocarbon.
He................................  helium.
\85\Kr............................  krypton 85.
N2................................  molecular nitrogen.
NH3...............................  ammonia.
NMHC..............................  nonmethane hydrocarbon.
NMHCE.............................  nonmethane hydrocarbon equivalent.
NO................................  nitric oxide.
NO2...............................  nitrogen dioxide.
NOX...............................  oxides of nitrogen.
N2O...............................  nitrous oxide.
NMOG..............................  nonmethane organic gases.
NONMHC............................  non-oxygenated nonmethane
                                     hydrocarbon.
NOTHC.............................  non-oxygenated total hydrocarbon.
O2................................  molecular oxygen.
OHC...............................  oxygenated hydrocarbon.
\210\Po...........................  polonium 210.
PM................................  particulate matter.
S.................................  sulfur.
SVOC..............................  semi-volatile organic compound.
THC...............................  total hydrocarbon.
THCE..............................  total hydrocarbon equivalent.
ZrO2..............................  zirconium dioxide.
------------------------------------------------------------------------

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

------------------------------------------------------------------------
                Symbol                         Quantity           Value
------------------------------------------------------------------------
[mu].................................  micro...................     10-6
m....................................  milli...................     10-3
c....................................  centi...................     10-2
k....................................  kilo....................      103
M....................................  mega....................      106
------------------------------------------------------------------------

    (d) Superscripts. This part uses the following superscripts to
define a quantity:

------------------------------------------------------------------------
            Superscript                           Quantity
------------------------------------------------------------------------
overbar (such as y)...............  arithmetic mean.
overdot (such as y)...............  quantity per unit time.
------------------------------------------------------------------------

    (e) Subscripts. This part uses the following subscripts to define a
quantity:

------------------------------------------------------------------------
             Subscript                            Quantity
------------------------------------------------------------------------
abs...............................  absolute quantity.
act...............................  actual condition.
air...............................  air, dry.
amb...............................  ambient.
atmos.............................  atmospheric.
bkgnd.............................  background.
cal...............................  calibration quantity.
CFV...............................  critical flow venturi.
comb..............................  combined.
composite.........................  composite value.
cor...............................  corrected quantity.
dil...............................  dilution air.
dew...............................  dewpoint.
dexh..............................  diluted exhaust.