(iv) Correct all concentrations measured on a "dry" basis to a "wet" basis, including dilution air background concentrations, as described in §1065.659.
(v) Calculate all NMHC and CH4 concentrations, including dilution air background concentrations, as described in §1065.660.
(vi) For emission testing with an oxygenated fuel, calculate any HC concentrations, including dilution air background concentrations, as described in §1065.665.  See subpart I of this part for testing with oxygenated fuels.
(vii) Correct all the NOx concentrations, including dilution air background concentrations, for intake-air humidity as described in §1065.670.
(2)	*	*	*
(i) Varying flow rate.  If you continuously sample from a changing exhaust flow rate, time align and then multiply concentration measurements by the flow rate from which you extracted it.  We consider the following to be examples of changing flows that require a continuous multiplication of concentration times molar flow rate: raw exhaust, exhaust diluted with a constant flow rate of dilution air, and CVS dilution with a CVS flow meter that does not have an upstream heat exchanger or electronic flow control.  This multiplication results in the flow rate of the emission itself.  Integrate the emission flow rate over a test interval to determine the total emission.  If the total emission is a molar quantity, convert this quantity to a mass by multiplying it by its molar mass, M.  The result is the mass of the emission, m.  Calculate m for continuous sampling with variable flow using the following equations:
*	*	*	*	*
(3) Batch sampling.  For batch sampling, the concentration is a single value from a proportionally extracted batch sample (such as a bag, filter, impinger, or cartridge).  In this case, multiply the mean concentration of the batch sample by the total flow from which the sample was extracted.  You may calculate total flow by integrating a changing flow rate or by determining the mean of a constant flow rate, as follows:
(i) Varying flow rate.  If you collect a batch sample from a changing exhaust flow rate, extract a sample proportional to the changing exhaust flow rate.  We consider the following to be examples of changing flows that require proportional sampling: raw exhaust, exhaust diluted with a constant flow rate of dilution air, and CVS dilution with a CVS flow meter that does not have an upstream heat exchanger or electronic flow control.  Integrate the flow rate over a test interval to determine the total flow from which you extracted the proportional sample.  Multiply the mean concentration of the batch sample by the total flow from which the sample was extracted. If the total emission is a molar quantity, convert this quantity to a mass by multiplying it by its molar mass, M.  The result is the mass of the emission, m.  In the case of PM emissions, where the mean PM concentration is already in units of mass per mole of sample,, simply multiply it by the total flow.  The result is the total mass of PM, mPM.  Calculate m for batch sampling with variable flow using the following equation:

      Eq. 1065.650-6
Example:
MNOx = 46.0055 g/mol
N = 9000
= 85.6 umol/mol = 85.6·10[-6] mol/mol
 = 25.534 mol/s
 = 26.950 mol/s
frecord = 5 Hz
Using Eq. 1065.650-5,
Δt = 1/5 = 0.2

mNOx = 4.201 g
(ii) Constant flow rate. If you batch sample from a constant exhaust flow rate, extract a sample at a proportional or constant flow rate. We consider the following to be examples of constant exhaust flows: CVS diluted exhaust with a CVS flow meter that has either an upstream heat exchanger, electronic flow control, or both. Determine the mean molar flow rate from which you extracted the constant flow rate sample.  Multiply the mean concentration of the batch sample by the mean molar flow rate of the exhaust from which the sample was extracted, and multiply the result by the time of the test interval.  If the total emission is a molar quantity, convert this quantity to a mass by multiplying it by its molar mass, M.  The result is the mass of the emission, m.  In the case of PM emissions, where the mean PM concentration is already in units of mass per mole of sample, , simply multiply it by the total flow, and the result is the total mass of PM, mPM.  Calculate m for sampling with constant flow using the following equations:

      Eq. 1065.650-7
and for PM or any other analysis of a batch sample that yields a mass per mole of sample,

      Eq. 1065.650-8
Example:
= 144.0 ug/mol = 144.0·10[-6] g/mol
= 57.692 mol/s
Δt = 1200 s
mPM = 144.0·10[-6]·57.692·1200
mPM = 9.9692 g
*	*	*	*	*
(d) Total work over a test interval.  To calculate the total work from the engine over a test interval, add the total work from all the work paths described in §1065.210 that cross the system boundary including electrical energy/work, mechanical shaft work, and fluid pumping work.  For all work paths, except the engine's primary output shaft (crankshaft), the total work for the path over the test interval is the integration of the net work flow rate (power) out of the system boundary.  When energy/work flows into the system boundary, this work flow rate signal becomes negative; in this case, include these negative work rate values in the integration to calculate total work from that work path.  Some work paths may result in a negative total work.  Include negative total work values from any work path in the calculated total work from the engine rather than setting the values to zero.  The rest of this paragraph (d) describes how to calculate total work from the engine's primary output shaft over a test interval.  Before integrating power on the engine's primary output shaft, adjust the speed and torque data for the time alignment used in §1065.514(c).  Any advance or delay used on the feedback signals for cycle validation must also be used for calculating work.  Account for work of accessories according to §1065.110.  Exclude any work during cranking and starting.  Exclude work during actual motoring operation (negative feedback torques), unless the engine was connected to one or more energy storage devices.  Examples of such energy storage devices include hybrid powertrain batteries and hydraulic accumulators, like the ones illustrated in Figure 1 of §1065.210.  Exclude any work during reference zero-load idle periods (0 % speed or idle speed with 0 N∙m reference torque).  Note, that there must be two consecutive reference zero load idle points to establish a period where this applies.  Include work during idle points with simulated minimum torque such as Curb Idle Transmissions Torque (CITT) for automatic transmissions in "drive".  The work calculation method described in paragraphs (d)(1) though (7) of this section meets these requirements using rectangular integration.  You may use other logic that gives equivalent results.  For example, you may use a trapezoidal integration method as described in paragraph (d)(8) of this section.
*	*	*	*	*
(7) Integrate the resulting values for power over the test interval.  Calculate total work as follows:

      Eq. 1065.650-10
Where:
W = total work from the primary output shaft
Pi = instantaneous power from the primary output shaft over an interval i.
Pi = fni · Ti
      Eq. 1065.650-11

Example:
N = 9000
fn1 = 1800.2 r/min
fn2 = 1805.8 r/min
T1 = 177.23 N∙m
T2 = 175.00 N∙m
Crev = 2∙PI rad/r
Ct1 = 60 s/min
Cp = 1000 (N∙m∙rad/s)/kW
frecord = 5 Hz
Ct2 = 3600 s/hr

P1 = 33.41 kW
P2 = 33.09 kW
Using Eq. 1065.650-5,
Δt = 1/5 = 0.2 s

W = 16.875 kW∙hr
*	*	*	*	*
(f)	*	*	*
(2) Total work.  To calculate a value proportional to total work over a test interval, integrate a value that is proportional to power.  Use information about the brake-specific fuel consumption of your engine, efuel, to convert a signal proportional to fuel flow rate to a signal proportional to power. To determine a signal proportional to fuel flow rate, divide a signal that is proportional to the mass rate of carbon products by the fraction of carbon in your fuel, wC..  You may use a measured wC or you may use default values for a given fuel as described in §1065.655(e).  Calculate the mass rate of carbon from the amount of carbon and water in the exhaust, which you determine with a chemical balance of fuel, DEF, intake air, and exhaust as described in §1065.655.  In the chemical balance, you must use concentrations from the flow that generated the signal proportional to molar flow rate, , in paragraph (e)(1) of this section.  Calculate a value proportional to total work as follows:
*	*	*	*	*
(g) Brake-specific emissions over a duty cycle with multiple test intervals.  The standard-setting part may specify a duty cycle with multiple test intervals, such as with discrete-mode steady-state testing.  Unless we specify otherwise, calculate composite brake-specific emissions over the duty cycle as described in this paragraph (g).  If a measured mass (or mass rate) is negative, set it to zero for calculating composite brake-specific emissions, but leave it unchanged for drift validation.  In the case of calculating composite brake-specific emissions relative to a combined emission standard (such as a NOx + NMHC standard), change any negative mass (or mass rate) values to zero for a particular pollutant before combining the values for the different pollutants.
(1) Use the following equation to calculate composite brake-specific emissions for duty cycles with multiple test intervals all with prescribed durations, such as cold-start and hot-start transient cycles:

      Eq. 1065.650-17
Where
i = test interval number.
N = number of test intervals.
WF = weighting factor for the test interval as defined in the standard-setting part.
m = mass of emissions over the test interval as determined in paragraph (c) of this section.
W = total work from the engine over the test interval as determined in paragraph (d) of this section.
Example:
N = 2
WF1 = 0.1428
WF2 = 0.8572
m1 = 70.125 g
m2 = 64.975 g
W1 = 25.783 kW∙hr
W2 = 25.783 kW∙hr

eNOxcomp = 2.548 g/kW∙hr
(2) Calculate composite brake-specific emissions for duty cycles with multiple test intervals that allow use of varying duration, such as discrete-mode steady-state duty cycles, as follows:
(i) Use the following equation if you calculate brake-specific emissions over test intervals based on total mass and total work as described in paragraph (b)(1) of this section:

      Eq. 1065.650-18
Where
i = test interval number.
N = number of test intervals.
WF = weighting factor for the test interval as defined in the standard-setting part.
m = mass of emissions over the test interval as determined in paragraph (c) of this section.
W = total work from the engine over the test interval as determined in paragraph (d) of this section.
t = duration of the test interval.
Example:
N = 2
WF1 = 0.85
WF2 = 0.15
m1 = 1.3753 g
m2 = 0.4135 g
t1 = 120 s
t2 = 200 s
W1 = 2.8375 kW∙hr
W2 = 0.0 kW∙hr

eNOxcomp = 0.5001 g/kW∙hr
(ii) Use the following equation if you calculate brake-specific emissions over test intervals based on the ratio of mass rate to power as described in paragraph (b)(2) of this section:

      Eq. 1065.650-19
Where
i = test interval number.
N = number of test intervals.
WF = weighting factor for the test interval as defined in the standard-setting part.
 = mean steady-state mass rate of emissions over the test interval as determined in paragraph (e) of this section.
 = mean steady-state power over the test interval as described in paragraph (e) of this section.
Example:
N = 2
WF1 = 0.85
WF2 = 0.15
= 2.25842 g/hr
 = 0.063443 g/hr
 = 4.5383 kW
 = 0.0 kW

eNOxcomp = 0.5001 g/kW∙hr
*	*	*	*	*

354. Amend §1065.655 by revising the section heading and paragraphs (a), (c) introductory text, (c)(3), (d) introductory text, (e), and (f)(3) to read as follows:
§1065.655  Chemical balances of fuel, DEF, intake air, and exhaust.
(a) General.  Chemical balances of fuel, intake air, and exhaust may be used to calculate flows, the amount of water in their flows, and the wet concentration of constituents in their flows.  With one flow rate of either fuel, intake air, or exhaust, you may use chemical balances to determine the flows of the other two.  For example, you may use chemical balances along with either intake air or fuel flow to determine raw exhaust flow.  Note that chemical balance calculations allow measured values for the flow rate of diesel exhaust fluid for engines with urea-based selective catalytic reduction.
*	*	*	*	*
(c) Chemical balance procedure.  The calculations for a chemical balance involve a system of equations that require iteration.  We recommend using a computer to solve this system of equations.  You must guess the initial values of up to three quantities: the amount of water in the measured flow, xH2Oexh, fraction of dilution air in diluted exhaust, xdil/exh, and the amount of products on a C1 basis per dry mole of dry measured flow, xCcombdry.  You may use time-weighted mean values of combustion air humidity and dilution air humidity in the chemical balance; as long as your combustion air and dilution air humidities remain within tolerances of +-0.0025 mol/mol of their respective mean values over the test interval.  For each emission concentration, x, and amount of water, xH2Oexh, you must determine their completely dry concentrations, xdry and xH2Oexhdry. You must also use your fuel mixture's atomic hydrogen-to-carbon ratio, α, oxygen-to-carbon ratio, β, sulfur-to-carbon ratio, γ, and nitrogen-to-carbon ratio, δ; you may optionally account for diesel exhaust fluid (or other fluids injected into the exhaust), if applicable.  You may calculate α, β, γ, and δ based on measured fuel composition or based on measured fuel and diesel exhaust fluid (or other fluids injected into the exhaust) composition together, as described in paragraph (e) of this section.  You may alternatively use any combination of default values and measured values as described in paragraph (e) of this section.  Use the following steps to complete a chemical balance:
*	*	*	*	*
(3) Use the following symbols and subscripts in the equations for performing the chemical balance calculations in this paragraph (c):
xdil/exh = amount of dilution gas or excess air per mole of exhaust.
xH2Oexh = amount of H2O in exhaust per mole of exhaust.
xCcombdry = amount of carbon from fuel and any injected fluids in the exhaust per mole of dry exhaust.
xH2dry = 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.
xH2Oexhdry = amount of H2O in exhaust per dry mole of dry exhaust.
xprod/intdry = amount of dry stoichiometric products per dry mole of intake air.
xdil/exhdry = amount of dilution gas and/or excess air per mole of dry exhaust.
xint/exhdry = amount of intake air required to produce actual combustion products per mole of dry (raw or diluted) exhaust.
xraw/exhdry = amount of undiluted exhaust, without excess air, per mole of dry (raw or diluted) exhaust.
xO2int = amount of intake air O2 per mole of intake air.
xCO2intdry = amount of intake air CO2 per mole of dry intake air. You may use xCO2intdry = 375 umol/mol, but we recommend measuring the actual concentration in the intake air.
xH2Ointdry = amount of intake air H2O per mole of dry intake air.
xCO2int = amount of intake air CO2 per mole of intake air.
xCO2dil = amount of dilution gas CO2 per mole of dilution gas.
xCO2dildry = amount of dilution gas CO2 per mole of dry dilution gas. If you use air as diluent, you may use xCO2dildry = 375 umol/mol, but we recommend measuring the actual concentration in the intake air.
xH2Odildry = amount of dilution gas H2O per mole of dry dilution gas.
xH2Odil = amount of dilution gas H2O per mole of dilution gas.
x[emission]meas = amount of measured emission in the sample at the respective gas analyzer.
x[emission]dry = amount of emission per dry mole of dry sample.
xH2O[emission]meas = amount of H2O in sample at emission-detection location.  Measure or estimate these values according to §1065.145(e)(2).
xH2Oint = amount of H2O in the intake air, based on a humidity measurement of intake air.
α = atomic hydrogen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids.
β = atomic oxygen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids.
γ = atomic sulfur-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids.
δ = atomic nitrogen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids.
*	*	*	*	*
(d) Carbon mass fraction of fuel.  Determine carbon mass fraction of fuel, wC, based on the fuel properties as determined in paragraph (e) of this section, optionally accounting for diesel exhaust fluid's contribution to α, β, γ, and δ, or other fluids injected into the exhaust, if applicable (for example, the engine is equipped with an emission control system that utilizes DEF).  Calculate wC using the following equation:
*	*	*	*	*
(e) Fuel and diesel exhaust fluid composition.  Determine fuel and diesel exhaust fluid composition represented by α, β, γ, and δ as described in this paragraph (e).  When using measured fuel or diesel exhaust fluid properties, you must determine values for α and β in all cases.  If you determine compositions based on measured values and the default value listed in Table 1 of this section is zero, you may set γ and δ to zero; otherwise determine γ and δ (along with α and β) based on measured values.  Determine elemental mass fractions and values for α, β, γ, and δ as follows:
(1) For liquid fuels, use the default values for α, β, γ, and δ in Table 1 of this section or determine mass fractions of liquid fuels for calculation of α, β, γ, and δ as follows:
(i) Determine the carbon and hydrogen mass fractions according to ASTM D5291 (incorporated by reference in §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.  This may include consulting with the instrument manufacturer on how to test high-volatility fuels.  Allow the weight of volatile fuel samples to stabilize for 20 minutes before starting the analysis; if the weight still drifts after 20 minutes, prepare a new sample).  Retest the sample if the carbon, hydrogen, oxygen, sulfur, and nitrogen mass fractions do not add up to a total mass of 100 +-0.5 %; if you do not measure oxygen, you may assume it has a zero concentration for this specification.  You may also assume that sulfur and nitrogen have a zero concentration for all fuels except residual fuel blends.
(ii) Determine oxygen mass fraction of gasoline (with or without blended ethanol) according to ASTM D5599 (incorporated by reference in §1065.1010).  For all other liquid fuels, determine the oxygen mass fraction using good engineering judgment.
(iii) Determine the nitrogen mass fraction according to ASTM D4629 or ASTM D5762 (incorporated by reference in §1065.1010) for all liquid fuels.  Select the correct method based on the expected nitrogen content.
(iv) Determine the sulfur mass fraction according to subpart H of this part.
(2) For gaseous fuels and diesel exhaust fluid, use the default values for α, β, γ, and δ in Table 1 of this section, or use good engineering judgment to determine those values based on measurement.
(3) For nonconstant fuel mixtures, you must account for the varying proportions of the different fuels.  This generally applies for dual-fuel and flexible-fuel engines, but it also applies if diesel exhaust fluid is injected in a way that is not strictly proportional to fuel flow.  Account for these varying concentrations either with a batch measurement that provides averaged values to represent the test interval, or by analyzing data from continuous mass rate measurements.  Application of average values from a batch measurement generally applies to situations where one fluid is a minor component of the total fuel mixture, for example dual-fuel and flexible-fuel engines with diesel pilot injection, where the diesel pilot fuel mass is less than 5 % of the total fuel mass and diesel exhaust fluid injection; consistent with good engineering judgment.
(4) Calculate α, β, γ, and δ using the following equations:

      Eq. 1065.655-20

	Eq. 1065.655-21

	Eq. 1065.655-22

	Eq. 1065.655-23
Where:
N = total number of fuels and injected fluids over the duty cycle.
j = an indexing variable that represents one fuel or injected fluid, starting with j = 1.
 = the mass flow rate of the fuel or any injected fluid j.  For applications using a single fuel and no DEF fluid, set this value to 1.  For batch measurements, divide the total mass of fuel over the test interval duration to determine a mass rate.
wHj = hydrogen mass fraction of fuel or any injected fluid j.
wCj = carbon mass fraction of fuel or any injected fluid j.
wOj = oxygen mass fraction of fuel or any injected fluid j.
wSj = sulfur mass fraction of fuel or any injected fluid j.
wNj = nitrogen mass fraction of fuel or any injected fluid j.
Example:
N = 1
j = 1
= 1
wH1 = 0.1239
wC1 = 0.8206
wO1 = 0.0547
wS1 = 0.00066
wN1 = 0.000095
MC = 12.0107
MH = 1.00794
MO = 15.9994
MS = 32.065
MN = 14.0067

α = 1.799
β = 0.05004
γ = 0.0003012
δ = 0.0001003
(5) Table 1 follows:
       Table 1 of §1065.655 - Default Values of α, β, γ, δ, and wC
                            Fuel or injected fluid
                               Atomic hydrogen,
                 oxygen, sulfur, and nitrogen-to-carbon ratios
                                CHαOβSγNδ
                                 Carbon mass
                                 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
                                 E100 Ethanol
                                  CH3O0.5S0N0
                                     0.521
                                 M100 Methanol
                                   CH4O1S0N0
                                     0.375
                                   #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
                             Residual fuel blends
Must be determined by measured fuel properties as described in paragraph (e)(1) of this section.
                             Diesel exhaust fluid
                               CH17.85O7.92S0N2
                                     0.065

(f)	*	*
(3) Fluid mass flow rate calculation.  This calculation may be used only for steady-state laboratory testing.  You may not use this calculation if the standard-setting part requires carbon balance error verification as described in §1065.543.  See §1065.915(d)(5)(iv) for application to field testing.  Calculate based on  using the following equation:

                  Eq. 1065.655-25
Where:
= raw exhaust molar flow rate from which you measured emissions.
j = an indexing variable that represents one fuel or injected fluid, starting with j = 1.
N = total number of fuels and injected fluids over the duty cycle.
= the mass flow rate of the fuel or any injected fluid j.
wCj = carbon mass fraction of the fuel and any injected fluid j.

Example:
N = 1
j = 1
= 7.559 g/s
wC1 = 0.869 g/g
MC = 12.0107 g/mol
xCcombdry1 = 99.87 mmol/mol = 0.09987 mol/mol
xH20exhdry1 = 107.64 mmol/mol = 0.10764 mol/mol

= 6.066 mol/s
*	*	*	**

355. Amend §1065.659 by revising paragraph (c)(2) and (3) to read as follows:
§1065.659  Removed water correction.
*	*	*	*	*
(c)	*	*	*
(2) If the measurement comes from raw exhaust, you may determine the amount of water based on intake-air humidity, plus a chemical balance of fuel, DEF, intake air, and exhaust as described in §1065.655.
(3) If the measurement comes from diluted exhaust, you may determine the amount of water based on intake-air humidity, dilution air humidity, and a chemical balance of fuel, DEF, intake air, and exhaust as described in §1065.655.
*	*	*	*	*

356. Amend §1065.660 by adding paragraphs (a)(5) and (6) and revising paragraphs (b)(2) introductory text, (b)(2)(ii) introductory text, (b)(2)(iii) introductory text, (b)(3) introductory text, (b)(4), (c)(2), and (d) introductory text, (d)(1) introductory text, (d)(1)(ii) introductory text, (d)(1)(iii) introductory text, (d)(2), and (e) to read as follows:
§1065.660  THC, NMHC, NMNEHC, CH4, and C2H6 determination.
(a) *	*	*
(5) You may calculate THC as the sum of NMHC and CH4 if you determine CH4 with an FTIR as described in §1065.660(d)(2) and NMHC with an FTIR using the additive method from §1065.660(b)(4).
(6) You may calculate THC as the sum of NMNEHC, C2H6, and CH4 if you determine CH4 with an FTIR as described in §1065.660(d)(2), C2H6 with an FTIR as described in §1065.660(e), and NMNEHC with an FTIR using the additive method from $ 1065.660(c)(3).
(b)	*	*	*
(2) For nonmethane cutters, calculate xNMHC using the nonmethane cutter's methane penetration fraction, PFCH4[NMC-FID], and the ethane response factor penetration fraction, RFPFC2H6[NMC-FID], from §1065.365, the THC FID's methane response factor, RFCH4[THC-FID], from §1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, xTHC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected methane concentration, xTHC[NMC-FID]cor, optionally corrected for initial THC contamination as determined in paragraph (a) of this section.
*	*	*	*	*
(ii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in §1065.365(e):
*	*	*	*	*
(iii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in §1065.365(f) or for penetration fractions determined as a function of molar water concentration using an NMC configuration as outlined in §1065.365(d):
*	*	*	*	*
(3) For a GC-FID or FTIR, calculate xNMHC using the THC analyzer's methane response factor, RFCH4[THC-FID], from §1065.360, and the initial THC contamination and dry-to-wet corrected THC concentration, xTHC[THC-FID]cor, as determined in paragraph (a) of this section as follows:
*	*	*	*	*
(4) For an FTIR, calculate xNMHC by summing the hydrocarbon species listed in §1065.266(c) as follows:

      Eq. 1065.660-6
   Where:
   xNMHC = concentration of NMHC.
   xHCi = the C1-equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination.
   xHCi-init = the C1-equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR.
   Example:
   xC2H6 = 4.9 umol/mol
   xC2H4 = 0.9 umol/mol
   xC2H2 = 0.8 umol/mol
   xC3H8 = 0.4 umol/mol
   xC3H6 = 0.5 umol/mol
   xC4H10 = 0.3 umol/mol
   xCH2O = 0.8 umol/mol
   xC2H4O = 0.3 umol/mol
   xCH2O2 = 0.1 umol/mol
   xCH4O = 0.1 umol/mol
   xNMHC = 4.9 + 0.9 + 0.8 + 0.4 + 0.5 + 0.3 + 0.8 + 0.3 + 0.1 + 0.1
   xNMHC = 9.1 umol/mol
(c)	*	*	*
(2) For a GC-FID, NMC FID, or FTIR, calculate xNMNEHC using the THC analyzer's methane response factor, RFCH4[THC-FID], and ethane response factor, RFC2H6[THC-FID], from §1065.360, the initial contamination and dry-to-wet corrected THC concentration, xTHC[THC-FID]cor, as determined in paragraph (a) of this section, the dry-to-wet corrected methane concentration, xCH4, as determined in paragraph (d) of this section, and the dry-to-wet corrected ethane concentration, xC2H6, as determined in paragraph (e) of this section as follows:

      Eq. 1065.660-7
   Where:
   xNMNEHC = concentration of NMNEHC.
   xTHC[THC-FID]cor = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID.
   RFCH4[THC-FID] = response factor of THC-FID to CH4.
   xCH4 = concentration of CH4, dry-to-wet corrected, as measured by the GC-FID, NMC FID, or FTIR.
   RFC2H6[THC-FID] = response factor of THC-FID to C2H6.
   xC2H6 = the C1-equivalent concentration of C2H6, dry-to-wet corrected, as measured by the GC-FID or FTIR.
   Example:
   xTHC[THC-FID]cor = 145.6 umol/mol
   RFCH4[THC-FID] = 0.970
   xCH4 = 18.9 umol/mol
   RFC2H6[THC-FID] = 1.02
   xC2H6 = 10.6 umol/mol
   xNMNEHC = 145.6  -  0.970 · 18.9  -  1.02 · 10.6
   xNMNEHC = 116.5 umol/mol
*	*	*	*	*
(d) CH4 determination.  Use one of the following methods to determine methane concentration, xCH4:
(1) For nonmethane cutters, calculate xCH4 using the nonmethane cutter's methane penetration fraction, PFCH4[NMC-FID], and the ethane response factor penetration fraction, RFPFC2H6[NMC-FID, from §1065.365, the THC FID's methane response factor, RFCH4[THC-FID], from §1065.360, the initial THC contamination and dry-to-wet corrected THC concentration, xTHC[THC-FID]cor, as determined in paragraph (a) of this section, and the dry-to-wet corrected methane concentration, xTHC[NMC-FID]cor, optionally corrected for initial THC contamination as determined in paragraph (a) of this section.
*	*	*	*	*
(ii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in §1065.365(e):
*	*	*	*	*
(iii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in §1065.365(f) or for penetration fractions determined as a function of molar water concentration using an NMC configuration as outlined in §1065.365(d):
*	*	*	*	*
(2) For a GC-FID or FTIR, xCH4 is the actual dry-to-wet corrected methane concentration as measured by the analyzer.
(e) C2H6 determination.  For a GC-FID or FTIR, xC2H6 is the C1-equivalent, dry-to-wet corrected ethane concentration as measured by the analyzer.

357. Amend §1065.665 by revising paragraph (a) to read as follows:
§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:

      Eq. 1065.665-1

                  Eq. 1065.665-2

      Eq. 1065.665-3
Where:
xTHCE = the sum of the C1-equivalent concentrations of non-oxygenated hydrocarbon, 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.
Mdexh = the molar mass of diluted exhaust as determine in §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.
*	*	*	*	*

358. Amend §1065.667 by revising paragraph (d) to read as follows:
§1065.667 Dilution air background emission correction.
*	*	*	*	*
(d) You may determine the total flow of dilution air from the measured dilute exhaust flow and a chemical balance of the fuel, DEF, intake air, and dilute exhaust as described in §1065.655.  For this option, the molar flow of dilution air is calculated by multiplying the dilute exhaust flow by the mole fraction of dilution gas to dilute exhaust, , from the dilute chemical balance. This may be done by totaling continuous calculations or by using batch results.  For example, to use batch results, the total flow of dilution air is calculated by multiplying the total flow of diluted exhaust, ndexh, by the flow-weighted mean mole fraction of dilution air in diluted exhaust, .  Calculate  using flow-weighted mean concentrations of emissions in the chemical balance, as described in §1065.655.  The chemical balance in §1065.655 assumes that your engine operates stoichiometrically, even if it is a lean-burn engine, such as a compression-ignition engine.  Note that for lean-burn engines this assumption could result in an error in emission calculations.  This error could occur because the chemical balance in §1065.655 treats excess air passing through a lean-burn engine as if it was dilution air. If an emission concentration expected at the standard is about 100 times its dilution air background concentration, this error is negligible.  However, if an emission concentration expected at the standard is similar to its background concentration, this error could be significant.  If this error might affect your ability to show that your engines comply with applicable standards, we recommend that you either determine the total flow of dilution air using one of the more accurate methods in paragraph (b) or (c) of this section, or remove background emissions from dilution air by HEPA filtration, chemical adsorption, or catalytic scrubbing.  You might also consider using a partial-flow dilution technique such as a bag mini-diluter, which uses purified air as the dilution air.
*	*	*	*	*

359. Amend §1065.675 by revising paragraph (d) to read as follows:
§1065.675  CLD quench verification calculations.
*	*	*	*	*
(d) Calculate quench as follows:

      Eq. 1065.675-1
Where:
quench = amount of CLD quench.
xNOdry = concentration of NO upstream of a humidity generator, according to §1065.370(e)(4).
xNOwet = measured concentration of NO downstream of a humidity generator, according to §1065.370(e)(9).
xH2Oexp = maximum expected mole fraction of water during emission testing, according to paragraph (b) of this section.
xH2Omeas = measured mole fraction of water during the quench verification, according to §1065.370(e)(7).
xNOmeas = measured concentration of NO when NO span gas is blended with CO2 span gas, according to §1065.370(d)(10).
xNOact = actual concentration of NO when NO span gas is blended with CO2 span gas, according to §1065.370(d)(11) and calculated according to Eq. 1065.675-2.
xCO2exp = maximum expected concentration of CO2 during emission testing, according to paragraph (c) of this section.
xCO2act = actual concentration of CO2 when NO span gas is blended with CO2 span gas, according to §1065.370(d)(9).

      Eq. 1065.675-2
Where:
xNOspan = the NO span gas concentration input to the gas divider, according to §1065.370(d)(5).
xCO2span = the CO2 span gas concentration input to the gas divider, according to §1065.370(d)(4).
Example:
xNOdry = 1800.0 umol/mol
xNOwet = 1739.6 umol/mol
xH2Oexp = 0.030 mol/mol
xH2Omeas = 0.030 mol/mol
xNOmeas = 1515.2 umol/mol
xNOspan = 3001.6 umol/mol
xCO2exp = 3.2 %
xCO2span = 6.1 %
xCO2act = 2.98 %

quench = ( - 0.0036655  -  0.014020171) ·100 % =  - 1.7685671 %

360. Amend §1065.695 by adding paragraph (c)(8)(v) to read as follows:
§1065.695  Data requirements.
*	*	*	*	*
(c)	*	*
(8)	*	*	*
(v) Carbon balance error verification, if performed.
*	*	*	*	*

361. Amend §1065.701 by revising paragarphs (b) and (f) to read as follows:
§1065.701  General requirements for test fuels.
*	*	*	*	*
(b) Fuels meeting alternate specifications. We may allow you to use a different test fuel (such as California LEV III gasoline) if it does not affect your ability to show that your engines would comply with all applicable emission standards using the specified test fuel.
*	*	*	*	*
(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 §1065.701 - Examples of Service-Accumulation and Field-Testing Fuels
                                 Fuel category
                                  Subcategory
                            Reference procedure[a]
Diesel
Light distillate and light blends with residual
ASTM D975

Middle distillate
ASTM D6985

Biodiesel (B100)
ASTM D6751
Intermediate and residual fuel
All
See §1065.705
Gasoline
Automotive gasoline
ASTM D4814

Automotive gasoline with ethanol concentration up to 10 volume %.
ASTM D4814
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
[a]Incorporated by reference; see §1065.1010.

362. Amend §1065.703 by revising paragraph (b) to read as follows:

§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 Table 1 of this section.
  Table 1 of §1065.703 - Test Fuel Specifications for Distillate Diesel Fuel
                                   Property
                                     Unit
                                   Ultra Low
                                    Sulfur
                                      Low
                                    Sulfur
                                     High
                                    Sulfur
                                   Reference
                                 Procedure[a]
Cetane Number
 --
40-50
40-50
40-50
ASTM D613
Distillation range:
Initial boiling point
10 pct. point
50 pct. point
90 pct. point
Endpoint
                                      °C

171-204
204-238
243-282
293-332
321-366

171-204
204-238
243-282
293-332
321-366

171-204
204-238
243-282
293-332
321-366

ASTM D86
Gravity
°API
32-37
32-37
32-37
ASTM D4052
Total sulfur
mg/kg
7-15
300-500
800-2500
ASTM D2622, ASTM D5453, or ASTM D7039
Aromatics, min. (Remainder shall be paraffins, naphthenes, and olefins)
g/kg
100
100
100
ASTM D5186
Flashpoint, min.
°C
54
54
54
ASTM D93
Kinematic Viscosity
mm[2]/s
2.0-3.2
2.0-3.2
2.0-3.2
ASTM D445
[a]Incorporated by reference, see §1065.1010.  See §1065.701(d) for other allowed procedures.

*	*	*	*	*

363. Amend §1065.705 by revising paragraph (c) to read as follows:
§1065.705  Residual and intermediate residual fuel.
*	*	*	*	*
(c) The fuel must meet the specifications for one of the categories in the following table:
Table 1 of §1065.705 - Service Accumulation and Test Fuel Specifications for Residual Fuel
                                   Property
                                     Unit
                                Category ISO-F-
                            Reference Procedure[a]

                                      RMA
                                      30
                                      RMB
                                      30
                                      RMD
                                      80
                                      RME
                                      180
                                      RMF
                                      180
                                      RMG
                                      380
                                      RMH
                                      380
                                      RMK
                                      380
                                      RMH
                                      700
                                      RMK
                                      700

Density at 15 °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 °C, max.
                                    mm[2]/s
                                     30.0
                                     80.0
                                     180.0
                                     380.0
                                     700.0
ISO 3104
Flash point, min.
                                      °C
                                      60
                                      60
                                      60
                                      60
                                      60
ISO 2719 (see also ISO 8217)
Pour point (upper)
Winter quality, max.
Summer quality, max.
                                      °C

                                       0
                                       6

                                      24
                                      24

                                      30
                                      30

                                      30
                                      30

                                      30
                                      30

                                      30
                                      30

ISO 3016
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, max.
                                   (kg/kg) %
                                     0.10
                                     0.10
                                     0.10
                                     0.10
                                     0.10
ISO 10307-2 (see also ISO 8217)
Aluminium plus silicon, max.
                                     mg/kg
                                      80
                                      80
                                      80
                                      80
                                      80
ISO 10478 or IP 501 or IP 470 (see also ISO 8217)
[a]Incorporated by reference; see §1065.1010.  See §1065.701(d) for other allowed procedures.

364. Amend §1065.710 by revising paragraphs (b)(2) and (c) to read as follows:
§1065.710  Gasoline.
*	*	*	*	*
(b)	*	*	*
(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 §1065.710 - Test Fuel Specifications
                    for a Low-Level Ethanol-Gasoline Blend
                                   Property
                                     Unit
                                 SPECIFICATION
                            Reference Procedure[a]

                                General Testing
                            Low-Temperature Testing
                             High Altitude Testing

Antiknock Index (R+M)/2
                                       -
                                 87.0-88.4[b]
                                 Minimum, 87.0
ASTM D2699 and
ASTM D2700
Sensitivity (R-M)
                                       -
                                 Minimum, 7.5
ASTM D2699 and
ASTM D2700
Dry Vapor Pressure Equivalent (DVPE)[c][,][d]
                                   kPa (psi)
                                  60.0-63.4
                                   (8.7-9.2)
                                   77.2-81.4
                                  (11.2-11.8)
                                  52.4-55.2
                                   (7.6-8.0)
ASTM D5191
Distillation[d]
                                                                10 % evaporated
                                   °C (°F)
                                     49-60
                                   (120-140)
                                    43-54
                                   (110-130)
                                     49-60
                                   (120-140)
ASTM D86
                                                                50 % evaporated
                                   °C (°F)
                                88-99 (190-210)

                                                                90 % evaporated
                                   °C (°F)
                               157-168 (315-335)

                                                 Evaporated final boiling point
                                   °C (°F)
                               193-216 (380-420)

Residue
                                  milliliter
                                 Maximum, 2.0

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[e]
                                   volume %
                                   4.0-10.0
ASTM D6550
Ethanol blended
                                   volume %
                                   9.6-10.0
See paragraph (b)(3) of this section.
Ethanol confirmatory[f]
                                   volume %
                                   9.4-10.2
ASTM D4815 or
ASTM D5599
Total Content of Oxygenates Other than Ethanol[f]
                                   volume %
                                 Maximum, 0.1
ASTM D4815 or
ASTM D5599
Sulfur
                                     mg/kg
                                   8.0-11.0
ASTM D2622, ASTM D5453 or ASTM D7039
Lead
                                    g/liter
                                Maximum, 0.0026
ASTM D3237
Phosphorus
                                    g/liter
                                Maximum, 0.0013
ASTM D3231
Copper Corrosion
                                       -
                                Maximum, No. 1
ASTM D130
Solvent-Washed Gum Content
                               mg/100 milliliter
                                 Maximum, 3.0
ASTM D381
Oxidation Stability
                                    minute
                                 Minimum, 1000
ASTM D525
[a]Incorporated by reference; see §1065.1010. See §1065.701(d) for other allowed procedures.
[b]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.
[c]Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, using the following equation: DVPE (kPa) = 0.956∙pT  -  2.39 or DVPE (psi) = 0.956∙pT  -  0.347.  DVPE is intended to be equivalent to Reid Vapor Pressure using a different test method.
[d]Parenthetical values are shown for informational purposes only.
[e]ASTM D6550 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 %.
[f]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.
*	*	*	*	*
(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 §1065.710 - Test Fuel Specifications for Neat (E0) Gasoline
                                   Property
                                     Unit
                                 SPECIFICATION
                            Reference Procedure[a]

                                General Testing
                            Low-Temperature Testing

Distillation Range:

ASTM D86
                                               Evaporated initial boiling point
                                      °C
24-35[b]
24-36

                                                                10 % evaporated
                                      °C
49-57
37-48

                                                                50 % evaporated
                                      °C
93-110
82-101

                                                                90 % evaporated
                                      °C
149-163
158-174

                                                 Evaporated final boiling point
                                      °C
Maximum, 213
Maximum, 212

Total Aromatic Hydrocarbons
                                   volume %
Maximum, 35
Maximum, 30.4
ASTM D1319 or ASTM D5769

Olefins[c]
                                   volume %
Maximum, 10
Maximum, 17.5
ASTM D1319 or ASTM D6550
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[d]
                                      kPa
60.0-63.4[b][,][e]
77.2-81.4
ASTM D5191
[a]Incorporated by reference; see §1065.1010.  See §1065.701(d) for other allowed procedures.
[b]For testing at altitudes above 1219 m, the specified initial boiling point range is (23.9 to 40.6) °C and the specified volatility range is (52.0 to 55.2) kPa.
[c]ASTM D6550 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 %.
[d]Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, in kPa using the following equation: DVPE (kPa) = 0.956∙pT  -  2.39 or DVPE (psi) = 0.956∙pT  -  0.347.  DVPE is intended to be equivalent to Reid Vapor Pressure using a different test method.
[e]For testing unrelated to evaporative emissions, the specified range is (55.2 to 63.4) kPa.

*	*	*	*	*

365. Amend §1065.715 by revising paragraph (a) to read as follows:
§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 §1065.715 - Test Fuel Specifications for Natural Gas
                                   Property
                                   Value[a]
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
[a]Demonstrate compliance with fuel specifications based on the reference procedures in ASTM D1945 (incorporated by reference in §1065.1010), or on other measurement procedures using good engineering judgment.  See §1065.701(d) for other allowed procedures.
*	*	*	*	*

366. Amend §1065.720 by revising paragraph (a) to read as follows:
§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 §1065.720(a) - Test Fuel Specifications for Liquefied Petroleum Gas
                                   Property
                                     Value
                            Reference Procedure[a]
Propane, C3H8
Minimum, 0.85 m[3]/m[3]
ASTM D2163
Vapor pressure at 38 °C
Maximum, 1400 kPa
ASTM D1267 or
ASTM D2598[b]
Volatility residue (evaporated temperature, 35 °C)
Maximum,  - 38 °C
ASTM D1837
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 of 100 ml oil stain observation)
Maximum, 0.05 ml pass[c]
ASTM D2158
Corrosion, copper strip
Maximum, No. 1
ASTM D1838
Sulfur
Maximum, 80 mg/kg
ASTM D6667
Moisture content
pass
ASTM D2713
[a]Incorporated by reference; see §1065.1010.  See §1065.701(d) for other allowed procedures.
[b]If these two test methods yield different results, use the results from ASTM D1267.
[c]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.

*	*	*	*	*

367. Amend §1065.750 by revising paragraph (a)(1)(ii) to read as follows:
§1065.750  Analytical gases.
(a)	*	*	*
(1)	*	*	*
(ii) Contamination as specified in the following table:
     Table 1 of §1065.750 - General Specifications for Purified Gases[a]
Constituent
Purified Air
Purified N2
THC (C1-equivalent)
<= 0.05 μmol/mol
<= 0.05 μmol/mol
CO
<= 1 μmol/mol
<= 1 μmol/mol
CO2
<= 10 μmol/mol
<= 10 μmol/mol
O2
0.205 to 0.215 mol/mol
<= 2 μmol/mol
NOx
<= 0.02 μmol/mol
<= 0.02 μmol/mol
N2O[b]
<= 0.02 μmol/mol
<= 0.02 μmol/mol
[a]We do not require these levels of purity to be NIST-traceable.
[b]The N2O limit applies only if the standard-setting part requires you to report N2O or certify to an N2O standard.

*	*	*	*	*

368. Amend §1065.790 by revising paragraph (b) to read as follows:
§1065.790  Mass standards.
*	*	*	*	*
(b) Dynamometer, fuel mass scale, and DEF mass scale calibration weights.  Use dynamometer and mass scale calibration weights that are certified as NIST-traceable within 0.1 % uncertainty.  Calibration weights may be certified by any calibration lab that maintains NIST-traceability.

369. Amend §1065.905 by revising paragraph (f) to read as follows:
§1065.905  General provisions.
*	*	*	*	*
(f) Summary.  The following table summarizes the requirements of paragraphs (d) and (e) of this section:
Table 1 of §1065.905 - Summary of Testing Requirements Specified Outside of This Subpart J
                                    Subpart
                      Applicability for field testing[a]
Applicability for laboratory or similar testing with PEMS without restriction[a]
Applicability for laboratory or similar testing with PEMS with restrictions[a]
A: Applicability and general provisions
Use all.
Use all.
Use all.
B: Equipment for testing
Use §1065.101 and §1065.140 through the end of subpart B, except §1065.140(e)(1) and (4), §1065.170(c)(1)(vi), and §1065.195(c).  §1065.910 specifies equipment specific to field testing.
Use all.
Use all.
§1065.910 specifies equipment specific to laboratory testing with PEMS.
C: Measurement instruments
Use all.
§1065.915 allows deviations.
Use all except §1065.295(c).
Use all except §1065.295(c).
§1065.915 allows deviations.
D: Calibrations and verifications
Use all except §1065.308 and §1065.309.
§1065.920 allows deviations, but also has additional specifications.
Use all.
Use all.
§1065.920 allows deviations, but also has additional specifications.
E: Test engine selection, maintenance, and durability
Do not use.
Use standard-setting part.
Use all.
Use all.
F: Running an emission test in the laboratory
Use §§1065.590 and 1065.595 for PM
§1065.930 and §1065.935 to start and run a field test.
Use all.
Use all.
G: Calculations and data requirements
Use all.
§1065.940 has additional calculation instructions
Use all.
Use all.
§1065.940 has additional calculation instructions
H: Fuels, engine fluids, analytical gases, and other calibration materials
Use all.
Use all.
Use all.
I: Testing with oxygenated fuels
Use all.
Use all.
Use all.
K: Definitions and reference materials
Use all.
Use all.
Use all.
[a]Refer to paragraphs (d) and (e) of this section for complete specifications.

370. Amend §1065.910 by revising paragraph (a)(2) to read as follows:
§1065.910  PEMS auxiliary equipment for field testing.
*	*	*	*	*
(a)	*	*	*
(2) Tubing.  We recommend using rigid 300 series stainless steel tubing to connect between flexible connectors.  Tubing may be straight or bent to accommodate vehicle geometry.  You may use "T" or "Y" fittings to join multiple connections, or you may cap or plug redundant flow paths if the engine manufacturer recommends it.
*	*	*	*	*

371. Amend §1065.915 by revising paragraph (a) to read as follows:
§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 §1065.905(b), the specifications in the following table apply instead of the specifications in Table 1 of §1065.205:
Table 1 of §1065.915 - Recommended Minimum PEMS Measurement Instrument Performance
                                  Measurement
                           Measured quantity symbol
                            Rise time, t10-90, and
                               Fall time, t90-10
                          Recording update frequency
                                  Accuracy[a]
                               Repeatability[a]
                                   Noise[a]
                            Engine speed transducer
                                      fn
                                      1 s
                                  1 Hz means
                                 5 % of pt. or
                                  1 % of max.
                                 2 % of pt. or
                                  1 % of max.
                                 0.5 % of max
                         Engine torque estimator, BSFC
                   (This is a signal from an engine's ECM)
                                   T or BSFC
                                      1 s
                                  1 Hz means
                                 8 % of pt. or
                                  5 % of max.
                                 2 % of pt. or
                                  1 % of max.
                                  1 % of max.
                          General pressure transducer
                      (not a part of another instrument)
                                       p
                                      5 s
                                     1 Hz
                                 5 % of pt. or
                                  5 % of max.
                                 2 % of pt. or
                                 0.5 % of max.
                                  1 % of max
                          Atmospheric pressure meter
                                    patmos
                                     50 s
                                    0.1 Hz
                                    250 Pa
                                    200 Pa
                                    100 Pa
                          General temperature sensor
                      (not a part of another instrument)
                                       T
                                      5 s
                                     1 Hz
                                1 % of pt. K or
                                      5 K
                               0.5 % of pt. K or
                                      2 K
                                 0.5 % of max
                                     0.5 K
                            General dewpoint sensor
                                     Tdew
                                     50 s
                                    0.1 Hz
                                      3 K
                                      1 K
                                      1 K
                              Exhaust flow meter
                               \s \* MERGEFORMAT
                                      1 s
                                  1 Hz means
                                 5 % of pt. or
                                  3 % of max.
                                  2 % of pt.
                                  2 % of max.
           Dilution air, inlet air, exhaust, and sample flow meters
                               \s \* MERGEFORMAT
                                      1 s
                                  1 Hz means
                                2.5 % of pt. or
                                 1.5 % of max.
                               1.25 % of pt. or
                                0.75 % of max.
                                  1 % of max.
                            Continuous gas analyzer
                                       x
                                      5 s
                                     1 Hz
                                 4 % of pt. or
                                 4 % of meas.
                                 2 % of pt. or
                                 2 % of meas.
                                  1 % of max.
                            Gravimetric PM balance
                                      mPM
                                       --
                                       --
                                See §1065.790
                                    0.5 μg
                                       --
                              Inertial PM balance
                                      mPM
                                       --
                                       --
                                 4 % of pt. or
                                 4 % of meas.
                                 2 % of pt. or
                                 2 % of meas.
                                  1 % of max
[a]Accuracy, repeatability, and noise are all determined with the same collected data, as described in §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.

*	*	*	*	*

372. Amend §1065.1001 by adding a definition for "Enhanced-idle" in alphabetical order and revising the definition for "Test interval" to read as follows:
§1065.1001  Definitions.
*	*	*	*	*
	Enhanced-idle means a mode of engine idle operation where idle speed is elevated above warm idle speed as determined by the electronic control module, for example during engine warm-up or to increase exhaust temperature.
*	*	*	*	*
	Test interval means a duration of time over which you determine mass of emissions.  For example, the standard-setting part may specify a complete laboratory duty cycle as a cold-start test interval, plus a hot-start test interval.  As another example, a standard-setting part may specify a field-test interval, such as a "not-to-exceed" (NTE) event, as a duration of time over which an engine operates within a certain range of speed and torque.  In cases where multiple test intervals occur over a duty cycle, the standard-setting part may specify additional calculations that weight and combine results to arrive at composite values for comparison against the applicable standards.
*	*	*	*	*

373. Amend §1065.1005 by revising paragraphs (a), (c), (d), (e), (f)(2), and (g) to read as follows:
§1065.1005  Symbols, abbreviations, acronyms, and units of measure.
*	*	*	*	*
(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
α
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]
β
ratio of diameters
meter per meter
m/m
1
β
atomic oxygen-to-carbon ratio
mole per mole
mol/mol
1
C#
number of carbon atoms in a molecule

c
power-specific carbon mass error coefficient
gram per kilowatt-hour
g/(kW∙hr)
3.6[-1]∙10[-][9]∙m[-2]∙s[2]
Cd
discharge coefficient

Cf
flow coefficient

δ
atomic nitrogen-to-carbon ratio
mole per mole
mol/mol
1
d
diameter
meter
m
m
d
power-specific carbon mass rate absolute error coefficent
gram per kilowatt-hour
g/(kW∙hr)
3.6[-1]∙10[-][9]∙m[-2]∙s[2]
DR
dilution ratio
mole per mole
mol/mol
1
ε
error between a quantity and its reference

ϵ
difference or error quantity

e
brake-specific emission or fuel consumption
gram per kilowatt hour
g/(kW∙hr)
3.6[-1]∙10[-][9]∙m[-2]∙s[2]
F
F-test statistic

f
frequency
hertz
Hz
s[-1]
fn
angular speed (shaft)
revolutions per minute
r/min
PI∙30[-1]·s[-1]
γ
ratio of specific heats
(joule per kilogram kelvin) per (joule per kilogram kelvin)
(J/(kg∙K))/(J/(kg∙K))
1
γ
atomic sulfur-to-carbon ratio
mole per mole
mol/mol
1
K
correction factor

1
Kv
calibration coefficient

m[4]∙s∙K[0.5]/kg
m[4]∙kg[-1]∙s∙K[0.5]
l
length
meter
m
m
L
limit

μ
viscosity, dynamic
pascal second
Pa∙s
m[-1]∙kg∙s[-1]
M
molar mass[a]
gram per mole
g/mol
10[-3]∙kg∙mol[-1]
m
mass
kilogram
kg
kg
\s \* MERGEFORMAT
mass rate
kilogram per second
kg/s
kg∙s[-1]
ν
viscosity, kinematic
meter squared per second
m[2]/s
m[2]∙s[-1]
N
total number in series

n
amount of substance
mole
mol
mol
\s \* MERGEFORMAT
amount of substance rate
mole per second
mol/s
mol∙s[-1]
P
power
kilowatt
kW
10[3]∙m[2]∙kg∙s[-3]
PF
penetration fraction

p
pressure
pascal
Pa
m[-1]∙kg∙s[-2]
ρ
mass density
kilogram per cubic meter
kg/m[3]
m[-3]∙kg
Δp
differential static pressure
pascal
Pa
m -1∙kg∙s[-2]
r
ratio of pressures
pascal per pascal
Pa/Pa
1
r[2]
coefficient of determination

Ra
average surface roughness
micrometer
μm
10[-6]∙m
Re[#]
Reynolds number

RF
response factor

RH
relative humidity

σ
non-biased standard deviation

S
Sutherland constant
kelvin
K
K
SEE
standard error of the estimate

T
absolute temperature
kelvin
K
K
T
Celsius temperature
degree Celsius
°C
K  -  273.15
T
torque (moment of force)
newton meter
N∙m
m[2]∙kg∙s[-2]
ϴ
plane angle
degrees
°
rad
t
time
second
s
s
Δt
time interval, period, 1/frequency
second
s
s
V
volume
cubic meter
m[3]
m[3]
\s \* MERGEFORMAT
volume rate
cubic meter per second
m[3]/s
m[3]∙s[-1]
W
work
kilowatt-hour
kW∙hr
3.6∙10[6]∙m[2]∙kg∙s[-2]
wC
carbon mass fraction
gram per gram
g/g
1
x
amount of substance mole fraction[b]
mole per mole
mol/mol
1
\s \* MERGEFORMAT
flow-weighted mean concentration
mole per mole
mol/mol
1
y
generic variable

Z
compressibility factor

aSee 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.
[b]Note that mole fractions for THC, THCE, NMHC, NMHCE, and NOTHC are expressed on a C1-equivalent basis.

*	*	*	*	*
(c) Prefixes.  This part uses the following prefixes for units and unit symbols:
                                    SYMBOL
                                  PREFIX NAME
                                    FACTOR
u
micro
10[-6]
m
milli
10[-3]
c
centi
10[-2]
k
kilo
10[3]
M
mega
10[6]

(d) Superscripts.  This part uses the following superscripts for modifying quantity symbols:
                                  SUPERSCRIPT
                                    MEANING
overbar (such as )
arithmetic mean
overdot (such as )
quantity per unit time

(e) Subscripts.  This part uses the following subscripts for modifying quantity symbols:
                                   SUBSCRIPT
                                    MEANING
a
absolute (e.g., absolute difference or error)
abs
absolute quantity
act
actual condition
air
air, dry
amb
ambient
atmos
atmospheric
bkgnd
background
C
carbon mass
cal
calibration quantity
CFV
critical flow venturi
comb
combined
comp
composite value
cor
corrected quantity
dil
dilution air
dew
dewpoint
dexh
diluted exhaust
dry
dry condition
dutycycle
duty cycle
ϵ
related to a difference or error quantity
exh
raw exhaust
exp
expected quantity
fluid
fluid stream
fn
feedback speed
frict
friction
fuel
fuel consumption
hi,idle
condition at high-idle
i
an individual of a series
idle
condition at idle
in
quantity in
init
initial quantity, typically before an emission test
int
intake air
j
an individual of a series
mapped
conditions over which an engine can operate
max
the maximum (i.e., peak) value expected at the standard over a test interval; not the maximum of an instrument range
meas
measured quantity
media
PM sample media
mix
mixture of diluted exhaust and air
norm
normalized
out
quantity out
P
power
part
partial quantity
PDP
positive-displacement pump
post
after the test interval
pre
before the test interval
prod
stoichiometric product
r
relative (e.g., relative difference or error)
rate
rate (divided by time)
record
record rate
ref
reference quantity
rev
revolution
sat
saturated condition
s
slip
span
span quantity
SSV
subsonic venturi
std
standard condition
stroke
engine strokes per power stroke
T
torque
test
test quantity
test,alt
alternate test quantity
uncor
uncorrected quantity
vac
vacuum side of the sampling system
weight
calibration weight
zero
zero quantity

(f)	*	*
(2) This part uses the following molar masses or effective molar masses of chemical species:
                                    SYMBOL
                                   QUANTITY
                                     g/mol
                             (10[-3]·kg·mol[-1])
Mair
molar mass of dry air[a]
28.96559
MAr
molar mass of argon
39.948
MC
molar mass of carbon
12.0107
MCH3OH
molar mass of methanol
32.04186
MC2H5OH
molar mass of ethanol
46.06844
MC2H4O
molar mass of acetaldehyde
44.05256
MCH4N2O
molar mass of urea
60.05526
MC2H6
molar mass of ethane
30.06904
MC3H8
molar mass of propane
44.09562
MC3H7OH
molar mass of propanol
60.09502
MCO
molar mass of carbon monoxide
28.0101
MCH4
molar mass of methane
16.0425
MCO2
molar mass of carbon dioxide
44.0095
MH
molar mass of atomic hydrogen
1.00794
MH2
molar mass of molecular hydrogen
2.01588
MH2O
molar mass of water
18.01528
MCH2O
molar mass of formaldehyde
30.02598
MHe
molar mass of helium
4.002602
MN
molar mass of atomic nitrogen
14.0067
MN2
molar mass of molecular nitrogen
28.0134
MNH3
molar mass of ammonia
17.03052
MNMHC
effective C1 molar mass of nonmethane hydrocarbon[b]
13.875389
MNMHCE
effective C1 molar mass of nonmethane hydrocarbon equivalent[b]
13.875389
MNMNEHC
effective C1 molar mass of nonmethane-nonethane hydrocarbon[b]
13.875389
MNOx
effective molar mass of oxides of nitrogen[c]
46.0055
MN2O
molar mass of nitrous oxide
44.0128
MO
molar mass of atomic oxygen
15.9994
MO2
molar mass of molecular oxygen
31.9988
MS
molar mass of sulfur
32.065
MTHC
effective C1 molar mass of total hydrocarbon[b]
13.875389
MTHCE
effective C1 molar mass of total hydrocarbon equivalent[b]
13.875389
[a]See paragraph (f)(1) of this section for the composition of dry air.
[b]The effective molar masses of THC, THCE, NMHC, NMHCE, and NMNEHC are defined on a C1 basis and are based on an atomic hydrogen-to-carbon ratio, α, of 1.85 (with β, γ, and δ equal to zero).
[c]The effective molar mass of NOx is defined by the molar mass of nitrogen dioxide, NO2.

[*]	*	*	*	*
(g) Other acronyms and abbreviations.  This part uses the following additional abbreviations and acronyms:
                                    ACRONYM
                                    MEANING
ABS
acrylonitrile-butadiene-styrene
ASTM
ASTM International
BMD
bag mini-diluter
BSFC
brake-specific fuel consumption
CARB
California Air Resources Board
CFR
Code of Federal Regulations
CFV
critical-flow venturi
CI
compression-ignition
CITT
Curb Idle Transmission Torque
CLD
chemiluminescent detector
CVS
constant-volume sampler
DEF
diesel exhaust fluid
DF
deterioration factor
ECM
electronic control module
EFC
electronic flow control
e.g.
exempli gratia, for example
EGR
exhaust gas recirculation
EPA
Environmental Protection Agency
FEL
Family Emission Limit
FID
flame-ionization detector
FTIR
Fourier transform infrared
GC
gas chromatograph
GC-ECD
gas chromatograph with an electron-capture detector
GC-FID
gas chromatograph with a flame ionization detector
HEPA
high-efficiency particulate air
IBP
initial boiling point
IBR
incorporated by reference
i.e.
id est, in other words
ISO
International Organization for Standardization
LPG
liquefied petroleum gas
MPD
magnetopneumatic detection
NDIR
nondispersive infrared
NDUV
nondispersive ultraviolet
NIST
National Institute for Standards and Technology
NMC
nonmethane cutter
PDP
positive-displacement pump
PEMS
portable emission measurement system
PFD
partial-flow dilution
PLOT
porous layer open tubular
PMD
paramagnetic detection
PMP
Polymethylpentene
pt.
a single point at the mean value expected at the standard.
psi
pounds per square inch
PTFE
polytetrafluoroethylene (commonly known as Teflon(TM))
RE
rounding error
RESS
rechargeable energy storage system
RFPF
response factor penetration fraction
RMC
ramped-modal cycle
rms
root-mean square
RTD
resistive temperature detector
SAW
surface acoustic wave
SEE
standard error of the estimate
SSV
subsonic venturi
SI
spark-ignition
THC-FID
total hydrocarbon flame ionization detector
TINV
inverse student t-test function in Microsoft Excel
UCL
upper confidence limit
UFM
ultrasonic flow meter
U.S.C.
United States Code

374. Amend §1065.1010 by revising paragraph (b) to read as follows:
§1065.1010  Incorporation by reference.
*	*	*	*	*
(b) ASTM material.  The following standards are available from ASTM International, 100 Barr Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428 - 2959, (877) 909 - ASTM, or http://www.astm.org:
(1) ASTM D86-12, Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure, approved December 1, 2012 ("ASTM D86"), IBR approved for §§1065.703(b) and 1065.710(b) and (c).
(2) ASTM D93-13, Standard Test Methods for Flash Point by Pensky- Martens Closed Cup Tester, approved July 15, 2013 ("ASTM D93"), IBR approved for §1065.703(b).
(3) ASTM D130-12, Standard Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test, approved November 1, 2012 ("ASTM D130"), IBR approved for §1065.710(b).
(4) ASTM D381-12, Standard Test Method for Gum Content in Fuels by Jet Evaporation, approved April 15, 2012 ("ASTM D381"), IBR approved for §1065.710(b).
(5) ASTM D445-12, Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity), approved April 15, 2012 ("ASTM D445"), IBR approved for §1065.703(b).
(6) ASTM D525-12a, Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method), approved September 1, 2012 ("ASTM D525"), IBR approved for §1065.710(b).
(7) ASTM D613-13, Standard Test Method for Cetane Number of Diesel Fuel Oil, approved December 1, 2013 ("ASTM D613"), IBR approved for §1065.703(b).
(8) ASTM D910-13a, Standard Specification for Aviation Gasolines, approved December 1, 2013 ("ASTM D910"), IBR approved for §1065.701(f).
(9) ASTM D975-13a, Standard Specification for Diesel Fuel Oils, approved December 1, 2013 ("ASTM D975"), IBR approved for §1065.701(f).
(10) ASTM D1267-12, Standard Test Method for Gage Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method), approved November 1, 2012 ("ASTM D1267"), IBR approved for §1065.720(a).
(11) ASTM D1319-13, Standard Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, approved May 1, 2013 ("ASTM D1319"), IBR approved for §1065.710(c).
(12) ASTM D1655-13a, Standard Specification for Aviation Turbine Fuels, approved December 1, 2013 ("ASTM D1655"), IBR approved for §1065.701(f).
(13) ASTM D1837-11, Standard Test Method for Volatility of Liquefied Petroleum (LP) Gases, approved October 1, 2011 ("ASTM D1837"), IBR approved for §1065.720(a).
(14) ASTM D1838-12a, Standard Test Method for Copper Strip Corrosion by Liquefied Petroleum (LP) Gases, approved December 1, 2012 ("ASTM D1838"), IBR approved for §1065.720(a).
(15) ASTM D1945-03 (Reapproved 2010), Standard Test Method for Analysis of Natural Gas by Gas Chromatography, approved January 1, 2010 ("ASTM D1945"), IBR approved for §1065.715(a).
(16) ASTM D2158-11, Standard Test Method for Residues in Liquefied Petroleum (LP) Gases, approved January 1, 2011 ("ASTM D2158"), IBR approved for §1065.720(a).
(17) ASTM D2163-07, Standard Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas Chromatography, approved December 1, 2007 ("ASTM D2163"), IBR approved for §1065.720(a).
(18) ASTM D2598-12, Standard Practice for Calculation of Certain Physical Properties of Liquefied Petroleum (LP) Gases from Compositional Analysis, approved November 1, 2012 ("ASTM D2598"), IBR approved for §1065.720(a).
(19) ASTM D2622-16, Standard Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry, approved January 1, 2016 ("ASTM D2622"), IBR approved for §§1065.703(b) and 1065.710(b) and (c).
(20) ASTM D2699-13b, Standard Test Method for Research Octane Number of Spark-Ignition Engine Fuel, approved October 1, 2013 ("ASTM D2699"), IBR approved for §1065.710(b).
(21) ASTM D2700-13b, Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel, approved October 1, 2013 ("ASTM D2700"), IBR approved for §1065.710(b).
(22) ASTM D2713-13, Standard Test Method for Dryness of Propane (Valve Freeze Method), approved October 1, 2013 ("ASTM D2713"), IBR approved for §1065.720(a).
(23) ASTM D2880-13b, Standard Specification for Gas Turbine Fuel Oils, approved November 15, 2013 ("ASTM D2880"), IBR approved for §1065.701(f).
(24) ASTM D2986-95a, Standard Practice for Evaluation of Air Assay Media by the Monodisperse DOP (Dioctyl Phthalate) Smoke Test, approved September 10, 1995 ("ASTM D2986"), IBR approved for §1065.170(c).  (Note: This standard was withdrawn by ASTM.)
(25) ASTM D3231-13, Standard Test Method for Phosphorus in Gasoline, approved June 15, 2013 ("ASTM D3231"), IBR approved for §1065.710(b) and (c).
(26) ASTM D3237-12, Standard Test Method for Lead in Gasoline By Atomic Absorption Spectroscopy, approved June 1, 2012 ("ASTM D3237"), IBR approved for §1065.710(b) and (c).
(27) ASTM D4052-11, Standard Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter, approved October 15, 2011 ("ASTM D4052"), IBR approved for §1065.703(b).
(28) ASTM D4629-12, Standard Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection, approved April 15, 2012 ("ASTM D4629"), IBR approved for §1065.655(e).
(29) ASTM D4814-13b, Standard Specification for Automotive Spark-Ignition Engine Fuel, approved December 1, 2013 ("ASTM D4814"), IBR approved for §1065.701(f).
(30) ASTM D4815-13, Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography, approved October 1, 2013 ("ASTM D4815"), IBR approved for §1065.710(b).
(31) ASTM D5186-03 (Reapproved 2009), Standard Test Method for Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels By Supercritical Fluid Chromatography, approved April 15, 2009 ("ASTM D5186"), IBR approved for §1065.703(b).
(32) ASTM D5191-13, Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method), approved December 1, 2013 ("ASTM D5191"), IBR approved for §1065.710(b) and (c).
(33) ASTM D5291-10, Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants, approved May 1, 2010 ("ASTM D5291"), IBR approved for §1065.655(e).
(34) ASTM D5453-19a , Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence, approved July 1, 2019 ("ASTM D5453"), IBR approved for §§1065.703(b) and 1065.710(b).
(35) ASTM D5599-00 (Reapproved 2010), Standard Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection, approved October 1, 2010 ("ASTM D5599"), IBR approved for §§1065.655(e) and 1065.710(b).
(36) ASTM D5762-12 Standard Test Method for Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence, approved April 15, 2012 ("ASTM D5762"), IBR approved for §1065.655(e).
(37) ASTM D5769-10, Standard Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry, approved May 1, 2010 ("ASTM D5769"), IBR approved for §1065.710(b).
(38) ASTM D5797-13, Standard Specification for Fuel Methanol (M70- M85) for Automotive Spark-Ignition Engines, approved June 15, 2013 ("ASTM D5797"), IBR approved for §1065.701(f).
(39) ASTM D5798-13a, Standard Specification for Ethanol Fuel Blends for Flexible Fuel Automotive Spark-Ignition Engines, approved June 15, 2013 ("ASTM D5798"), IBR approved for §1065.701(f).
(40) ASTM D6348-12[ε1], Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy, approved February 1, 2012 ("ASTM D6348"), IBR approved for §§1065.266(b) and 1065.275(b).
(41) ASTM D6550-10, Standard Test Method for Determination of Olefin Content of Gasolines by Supercritical-Fluid Chromatography, approved October 1, 2010 ("ASTM D6550"), IBR approved for §1065.710(b).
(42) ASTM D6615-11a, Standard Specification for Jet B Wide-Cut Aviation Turbine Fuel, approved October 1, 2011 ("ASTM D6615"), IBR approved for §1065.701(f).
(43) ASTM D6667-14 (Reapproved 2019), Standard Test Method for Determination of Total Volatile Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum Gases by Ultraviolet Fluorescence, approved May 1, 2019 ("ASTM D6667"), IBR approved for §1065.720(a).
(44) ASTM D6751-12, Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels, approved August 1, 2012 ("ASTM D6751"), IBR approved for §1065.701(f).
(45) ASTM D6985-04a, Standard Specification for Middle Distillate Fuel Oil -- Military Marine Applications, approved November 1, 2004 ("ASTM D6985"), IBR approved for §1065.701(f).  (Note: This standard was withdrawn by ASTM.)
(46) ASTM D7039-15a (Reapproved 2020), Standard Test Method for Sulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine, Biodiesel, Biodiesel Blends, and Gasoline-Ethanol Blends by Monochromatic Wavelength Dispersive X-ray Fluorescence Spectrometry, approved May 1, 2020 ("ASTM D7039"), IBR approved for §§1065.703(b) and 1065.710(b).
(47) ASTM F1471-09, Standard Test Method for Air Cleaning Performance of a High- Efficiency Particulate Air Filter System, approved March 1, 2009 ("ASTM F1471"), IBR approved for §1065.1001.
*	*	*	*	*

Part 1066 -- VEHICLE-TESTING PROCEDURES
375. The authority citation for part 1066 continues to read as follows:
Authority: 42 U.S.C. 7401 - 7671q.

376. Amend §1066.1 by revising paragraph (g) to read as follows:
§1066.1  Applicability.
*	*	*	*	*
(g) For additional information regarding these test procedures, visit our Web site at www.epa.gov, and in particular https://www.epa.gov/vehicle-and-fuel-emissions-testing/vehicle-testing-regulations.

377. Amend §1066.135 by revising paragraph (a)(1) to read as follows:
§1066.135  Linearity verification.
*	*	*	*	*
(a)	*	*	*
(1) Use instrument manufacturer recommendations and good engineering judgment to select at least ten reference values, yrefi, that cover the range of values that you expect during testing (to prevent extrapolation beyond the verified range during emission testing).  We recommend selecting zero as one of your reference values.  For each range calibrated, if the deviation from a least-squares best-fit straight line is 2 % or less of the value at each data point, concentration values may be calculated by use of a straight-line curve fit for that range.  If the deviation exceeds 2 % at any point, use the best-fit nonlinear equation that represents the data to within 2 % of each test point to determine concentration.  If you use a gas divider to blend calibration gases, you may verify that the calibration curve produced names a calibration gas within 2 % of its certified concentration.  Perform this verification between 10 and 60 % of the full-scale analyzer range.
*	*	*	*	*

378. Amend §1066.210 by revising paragraph (d)(3) to read as follows:
§1066.210  Dynamometers.
*	*	*	*	*
(d)	*	*	*
(3) The load applied by the dynamometer simulates forces acting on the vehicle during normal driving according to the following equation:

	Eq. 1066.210-1
Where:
FR = total road-load force to be applied at the surface of the roll.  The total force is the sum of the individual tractive forces applied at each roll surface.
i = a counter to indicate a point in time over the driving schedule.  For a dynamometer operating at 10-Hz intervals over a 600-second driving schedule, the maximum value of i should be 6,000.
A = a vehicle-specific constant value representing the vehicle's frictional load in lbf or newtons.  See subpart D of this part.
Gi = instantaneous road grade, in percent.  If your duty cycle is not subject to road grade, set this value to 0.
B = a vehicle-specific coefficient representing load from drag and rolling resistance, which are a function of vehicle speed, in lbf/(mi/hr) or N∙s/m.  See subpart D of this part.
v = instantaneous linear speed at the roll surfaces as measured by the dynamometer, in mi/hr or m/s.  Let vi - 1 = 0 for i = 0.
C = a vehicle-specific coefficient representing aerodynamic effects, which are a function of vehicle speed squared, in lbf/(mi/hr)[2] or N∙s[2]/m[2].  See subpart D of this part.
Me = the vehicle's effective mass in lbm or kg, including the effect of rotating axles as specified in §1066.310(b)(7).
t = elapsed time in the driving schedule as measured by the dynamometer, in seconds.  Let ti - 1 = 0 for i = 0.
M = the measured vehicle mass, in lbm or kg.
ag = acceleration of Earth's gravity = 9.80665 m/s[2].
*	*	*	*	*

379. Amend §1066.255 by revising paragraph (c) to read as follows:
§1066.255  Parasitic loss verification.
*	*	*	*	*
(c) Procedure.  Perform this verification by following the dynamometer manufacturer's specifications to establish a parasitic loss curve, taking data at fixed speed intervals to cover the range of vehicle speeds that will occur during testing.  You may zero the load cell at a selected speed if that improves your ability to determine the parasitic loss.  Parasitic loss forces may never be negative.  Note that the torque transducers must be mathematically zeroed and spanned prior to performing this procedure.
*	*	*	*	*

380. Amend §1066.260 by revising paragraph (c)(4) to read as follows:
§1066.260  Parasitic friction compensation evaluation.
*	*	*	*	*
(c)	*	*	*
(4) Calculate the power equivalent of friction compensation error, FCerror, using the following equation:

      Eq. 1066.260-1
Where:
I = dynamometer inertia setting.
t = duration of the measurement interval, accurate to at least 0.01 s.
vinit = the roll speed corresponding to the start of the measurement interval, accurate to at least 0.05 mi/hr.
vfinal = the roll speed corresponding to the end of the measurement interval, accurate to at least 0.05 mi/hr.
Example:
I = 2000 lbm = 62.16 lbf·s[2]/ft
t = 60.0 s
vinit = 9.2 mi/hr = 13.5 ft/s
vfinal = 10.0 mi/hr = 14.7 ft/s

FCerror =  - 17.5 ft∙lbf/s =  - 0.032 hp
*	*	*	*	*

381. Amend §1066.265 by revising paragraph (d)(1) to read as follows:
§1066.265  Acceleration and deceleration verification.
*	*	*	*	*
(d)	*	*	*
(1) Calculate the force setting, F, using the following equation:

      Eq. 1066.265-4
Where:
Ib = the dynamometer manufacturer's stated base inertia, in lbf·s[2]/ft.
a = nominal acceleration rate, in ft/s[2].
Example:
Ib = 2967 lbm = 92.217 lbf·s[2]/ft
a = 1 (mi/hr)/s = 1.4667 ft/s[2]

F = 135.25 lbf
*	*	*	*	*

382. Amend §1066.270 by revising paragraphs (c)(4) and (d)(2) to read as follows:
§1066.270  Unloaded coastdown verification.
*	*	*	*	*
(c)	*	*	*
(4) Determine the mean coastdown force, , for each speed and inertia setting for each of the coastdowns performed using the following equation:

      Eq. 1066.270-1
Where:
 = the mean force measured during the coastdown for each speed interval and inertia setting, expressed in lbf and rounded to four significant figures.
I = the dynamometer's inertia setting, in lbf·s[2]/ft.
vinit = the speed at the start of the coastdown interval, expressed in ft/s to at least four significant figures.
vfinal = the speed at the end of the coastdown interval, expressed in ft/s to at least four significant figures.
t = coastdown time for each speed interval and inertia setting, accurate to at least 0.01 s.
Example:
I = 2000 lbm = 62.16 lbf·s[2]/ft
vinit = 25 mi/hr = 36.66 ft/s
vfinal = 15 mi/hr = 22.0 ft/s
t = 5.00 s

 = 182.3 lbf
*	*	*	*	*
(d)	*	*	*
(2) For vehicles above 20,000 pounds GVWR, the maximum allowable error, Ferrormax, for all speed intervals and inertia settings is 1.0 % or the value determined from Eq. 1066.270-3 (substituting 8.8 lbf for 2.2 lbf in the numerator), whichever is greater.
*	*	*	*	*

383. Amend §1066.275 by revising paragraphs (b) and (d) to read as follows:
§1066.275  Daily dynamometer readiness verification.
*	*	*	*	*
(b) Scope and frequency.  Perform this verification upon initial installation, within 1 day before testing, and after major maintenance.  You may run this within 7 days before testing if you accumulate data to support a less frequent verification interval.
*	*	*	*	*
(d) Performance evaluation. The coastdown force error determined in paragraph (c) of this section may not exceed the following:
   (1) For vehicles at or below 20,000 pounds GVWR, 1.0 % or the value determined from Eq. 1066.270-3, whichever is greater.
   (2) For vehicles above 20,000 pounds GVWR, 1.0 % or the value determined from Eq. 1066.270-3 (substituting 8.8 lbf for 2.2 lbf), whichever is greater.
*	*	*	*	*

384. Revise §1066.405 to read as follows:
§1066.405  Vehicle preparation, preconditioning, and maintenance.
(a) Prepare the vehicle for testing (including measurement of evaporative and refueling emissions if appropriate), as described in the standard-setting part.
(b) If you inspect a vehicle, keep a record of the inspection and update your application for certification to document any changes that result.  You may use any kind of equipment, instrument, or tool that is available at dealerships and other service outlets to identify malfunctioning components or perform maintenance.
(c) You may repair defective parts from a test vehicle if they are unrelated to emission control.  You must ask us to approve repairs that might affect the vehicle's emission controls.  If we determine that a part failure, system malfunction, or associated repair makes the vehicle's emission controls unrepresentative of production engines, you may not use it as an emission-data vehicle.  Also, if the engine installed in the test vehicle has a major mechanical failure that requires you to take the vehicle apart, you may no longer use the vehicle as an emission-data vehicle for exhaust measurements.

385. Amend §1066.420 by revising paragraph (d) to read as follows:
§1066.420  Test preparation.
*	*	*	*	*
(d) Control test cell ambient air humidity as follows:
(1) For vehicles at or below 14,000 pounds GVWR, follow the humidity requirements in Table 1 of this section, unless the standard-setting part specifies otherwise.  When complying with humidity requirements in the table, where no tolerance is specified, use good engineering judgment to maintain the humidity level near the specified value within the limitations of your test facility.
(2) For vehicles above 14,000 pounds GVWR, you may test vehicles at any humidity.
(3) Table 1 follows:
            Table 1 of §1066.420 - Test Cell Humidity Requirements
                                  Test cycle
            Humidity requirement    (grains H2O per pound dry air)
                   Tolerance (grains H2O per pound dry air)
AC17
                                      69
                                +- 5 average,
                              +- 10 instantaneous
FTP[a] and LA-92
                                      50

HFET
                                      50

SC03
                                      100
                                 +- 5 average
US06
                                      50

[a]FTP humidity requirement does not apply for cold ( - 7°C), intermediate (10 °C), and hot (35 °C) temperature testing.

*	*	*	*	*
386. Amend §1066.605 by revising paragraphs (c)(4) and (h)(2)(i) to read as follows:
§1066.605  Mass-based and molar-based exhaust emission calculations.
*	*	*	*	*
(c)	*	*	*
(4) For vehicles at or below 14,000 pounds GVWR, calculate HC concentrations, including dilution air background concentrations, as described in this section, and as described in §1066.635 for NMOG.  For emission testing of vehicles above 14,000 pounds GVWR, with fuels that contain 25 % or more oxygenated compounds by volume, calculate THCE and NMHCE concentrations, including dilution air background concentrations, as described in 40 CFR part 1065, subpart I.
*	*	*	*	*
(h)	*	*	*
(2)	*	*	*
(i) Varying flow rate.  If you continuously sample from a varying exhaust flow rate, calculate V[flow] using the following equation:

      Eq. 1066.605-10
Where:
∆t = 1/frecord
      Eq. 1066.605-11
Example:
N = 505
= 0.276 m[3]/s
= 0.294 m[3]/s
frecord = 1 Hz
Using Eq. 1066.605-11,
t = 1/1 = 1 s

VCVS = 170.721 m[3]
*	*	*	*	*

387. Amend §1066.610 by revising paragraph (d) to read as follows:
§1066.610  Dilution air background correction.
*	*	*	*	*
(d) Determine the time-weighted dilution factor, DFw, over the duty cycle using the following equation:

      Eq. 1066.610-4
Where:
N = number of test intervals.
i = test interval number
t = duration of the test interval.
DF = dilution factor over the test interval.
Example:
N = 3
DF1 = 14.40
t1 = 505 s
DF2 = 24.48
t2 = 867 s
DF3 = 17.28
t3 = 505 s

388. Amend §1066.710 by revising paragraph (c) to read as follows:
§1066.710  Cold temperature testing procedures for measuring CO and NMHC emissions and determining fuel economy.
*	*	*	*	*
(c) Heater and defroster.  During the test, operate the vehicle's interior climate control system with the heat on and air conditioning off.  You may not use any supplemental auxiliary heat during this testing.  You may set the heater to any temperature and fan setting during vehicle preconditioning.
(1) Manual and automatic temperature control. Unless you rely on full automatic control as specified in paragraph (c)(2) of this section, take the following steps to control heater settings:
(i) Set the climate control system as follows before the first acceleration (t = 20 s), or before starting the vehicle if the climate control system allows it:
(A) Temperature.  Set controls to maximum heat.  For automatic temperature control systems that allow the operator to select a specific temperature, set the heater control to 72 °F or higher.
(B) Fan speed.  Set the fan speed to full off or the lowest available speed if a full off position is not available.
(C) Airflow direction.  Direct airflow to the front window (window defrost mode).
(D) Air source.  If independently controllable, set the system to draw in outside air.
(ii) At the second idle of the test cycle, which occurs 125 seconds after the start of the test, set the fan speed to maximum.  Complete by 130 seconds after the start of the test.  Leave temperature and air source settings unchanged
(iii) At the sixth idle of the test interval, which occurs at the deceleration to zero miles per hour 505 seconds after the start of the test, set the fan speed to the lowest setting that maintains air flow.  Complete these changes by 510 seconds after the start of the test.  You may use different vent and fan speed settings for the remainder of the test.  Leave the temperature and air source settings unchanged.
(2) Full automatic control.  Vehicles with full automatic control systems may instead operate as described in this paragraph (c)(2).  Set the temperature to 72 °F in full automatic control for the whole test, allowing the vehicle to adjust the air temperature and direction of the airflow.
(3) Multiple-zone systems.  For vehicles that have separate driver and passenger controls or separate front and rear controls, you must set all temperature and fan controls as described in paragraphs (c)(1) and (2) of this section, except that rear controls need not be set to defrost the front window.
(4) Alternative test procedures.  We may approve the use of other settings under 40 CFR 86.1840 if a vehicle's climate control system is not compatible with the provisions of this section.
*	*	*	*	*

389. Amend §1066.801 by revising paragraph (e) to read as follows:
§1066.801  Applicability and general provisions.
*	*	*	*	*
(e) The following figure illustrates the FTP test sequence for measuring exhaust and evaporative emissions:

                  Figure 1 of §1066.801 - FTP test sequence

390. Amend §1066.835 by revising paragraphs (a) and (f)(2) to read as follows:
§1066.835  Exhaust emission test procedure for SC03 emissions.
*	*	*	*	*
(a) Drain and refill the vehicle's fuel tank(s) if testing starts more than 72 hours after the most recent FTP or HFET measurement (with or without evaporative emission measurements).
*	*	*	*	*
(f)	*	*	*
(2) Conditions before and after testing.  Use good engineering judgment to demonstrate that you meet the specified temperature and humidity tolerances in paragraph (f)(1) of this section at all times before and between emission measurements.
*	*	*	*	*

391. Revise §1066.930 to read as follows:
§1066.930  Equipment for point-source measurement of running losses.
For point-source measurement of running loss emissions, use equipment meeting the specifications in 40 CFR 86.107-96(i).

392. Amend §1066.1005 by revising paragraphs (a), (c), (d), (e), and (f) to read as follows:
§1066.1005  Symbols, abbreviations, acronyms, and units of measure.
*	*	*	*	*
(a) Symbols for quantities.  This part uses the following symbols and units of measure for various quantities:
                                    SYMBOL
                                   QUANTITY
                                     UNIT
                                  UNIT SYMBOL
                        UNIT IN TERMS OF SI BASE UNITS

atomic hydrogen to carbon ratio
mole per mole
mol/mol
1
A
area
square meter
m[2]
m[2]
A
vehicle frictional load
pound force or newton
lbf or N
m∙kg∙s[-2]
ag
acceleration of Earth's gravity
meters per second squared
m/s[2]
m∙s[-2]
Am
calculated vehicle frictional load
pound force or newton
lbf or N
m∙kg∙s[-2]
a0
intercept of least squares regression

a1
slope of least squares  regression

a
acceleration
feet per second squared or meters per second squared
ft/s[2] or m/s[2]
m∙s[-2]
B
vehicle load from drag and rolling resistance
pound force per mile per hour or newton second per meter
lbf/(mi/hr) or N∙s/m
kg∙s[-][1]

ratio of diameters
meter per meter
m/m
1

atomic oxygen to carbon ratio
mole per mole
mol/mol
1
c
conversion factor

C
vehicle-specific aerodynamic effects
pound force per mile per hour squared or newton-second squared per meter squared
lbf/(mi/hr)[2] or N∙s[2]/m[2]
m[-][1]∙kg
C#
number of carbon atoms in a molecule
C#
number of carbon atoms in a molecule
C#
Cd
discharge coefficient

CdA
drag area
meter squared
m[2]
m[2]
Cf
flow coefficient

Cp
heat capacity at constant pressure
joule per kelvin
J/K
m[2]∙kg∙s[-2]∙K[-][1]
Cv
heat capacity at constant volume
joule per kelvin
J/K
m[2]∙kg∙s[-2]∙K[-][1]
d
diameter
meters
m
m
D
distance
miles or meters
mi or m
m
D
slope correlation
pound force per mile per hour squared or newton second squared per meter squared
lbf/(mi/hr)[2] or N∙s[2]/m[2]
m[-2]∙kg
DF
dilution factor

1
e
mass weighted emission result
grams/mile
g/mi

F
force
pound force or newton
lbf or N
kg∙s[-2]
f
frequency
hertz
Hz
s[-1]
fn
angular speed (shaft)
revolutions per minute
r/min
PI∙30·s[-1]
FC
friction compensation error
horsepower or watt
W
m[2]·kg·s[-][3]
FR
road-load force
pound force or newton
lbf or N
kg∙s[-2]

ratio of specific heats
(joule per kilogram kelvin) per (joule per kilogram kelvin)
(J/(kg∙K))/(J/(kg∙K))
1

ambient humidity
grams water vapor per kilogram dry air
g H2O vapor/kg dry air
g H2O vapor/kg dry air
h
change in height
meters
m
m
I
inertia
pound mass or kilogram
lbm or kg
kg
I
current
ampere
A
A
i
indexing variable

IR
inertia work rating

K
correction factor

1
Kv
calibration coefficient

m[4]∙s∙K[0.5]/kg
m[4]∙kg[-1]∙s∙K[0.5]

viscosity, dynamic
pascal second
Pa∙s
m[-1]∙kg∙s[-1]
M
molar mass
gram per mole
g/mol
10[-3]∙kg∙mol[-1]
Me
effective mass
kilogram
kg
kg
m
mass
pound mass or kilogram
lbm or kg
kg
N
total number in series

n
total number of pulses in a series

p
pressure
pascal
Pa
m -[1]∙kg∙s[-2]
p
differential static pressure
pascal
Pa
m -[1]∙kg∙s[-2]
pd
saturated vapor pressure at ambient dry bulb temperature
kilopascal
kPa
m -[1]∙kg∙s[-2]
PF
penetration fraction

ρ
mass density
kilogram per cubic meter
kg/m[3]
m[-3]∙kg
R
dynamometer roll revolutions
revolutions per minute
rpm
PI∙30[-1]·s[-1]
r
ratio of pressures
pascal per pascal
Pa/Pa
1
r[2]
coefficient of determination

Re[#]
Reynolds number

RF
response factor

RH
relative humidity

S
Sutherland constant
kelvin
K
K
SEE
standard error of the estimate

SG
specific gravity

s
distance traveled during measurement interval
meters
m
m
T
absolute temperature
kelvin
K
K
T
Celsius temperature
degree Celsius
°C
K  -  273.15
T
torque (moment of force)
newton meter
N∙m
m[2]∙kg∙s[-2]
t
time
hour or second
hr or s
s
Δt
time interval, period, 1/frequency
second
s
s
U
voltage
volt
V
m[2]∙kg∙s[-3]∙A[-1]
v
speed
miles per hour or meters per second
mi/hr or m/s
m∙s[-1]
V
volume
cubic meter
m[3]
m[3]

flow volume rate
cubic feet per minute or cubic meter per second
ft[3]/min or m[3]/s
m[3]∙/s[-1]
VP
volume percent

x
concentration of emission over a test interval
part per million
ppm

y
generic variable

Z
compressibility factor

*	*	*	*	*
(c) Superscripts.  This part uses the following superscripts for modifying quantity symbols:
                                  SUPERSCRIPT
                                    MEANING
overbar (such as )
arithmetic mean
overdot (such as )
quantity per unit time

(d) Subscripts.  This part uses the following subscripts for modifying quantity symbols:
                                   SUBSCRIPT
                                    MEANING
0
reference
abs
absolute quantity
AC17
air conditioning 2017 test interval
act
actual or measured condition
actint
actual or measured condition over the speed interval
adj
adjusted
air
air, dry
atmos
atmospheric
b
base
bkgnd
background
c
cold
comp
composite
cor
corrected
cs
cold stabilized
ct
cold transient
cUDDS
cold-start UDDS
D
driven
dew
dewpoint
dexh
dilute exhaust quantity
dil
dilute
e
effective
emission
emission specie
error
error
EtOH
ethanol
exh
raw exhaust quantity
exp
expected quantity
fil
filter
final
final
flow
flow measurement device type
gas
gaseous
h
hot
HFET
highway fuel economy test
hs
hot stabilized
ht
hot transient
hUDDS
hot-start UDDS
i
an individual of a series
ID
driven inertia
in
inlet
int
intake
init
initial quantity, typically before an emission test
IT
target inertia
liq
liquid
max
the maximum (i.e., peak) value expected at the standard over a test interval; not the maximum of an instrument range
meas
measured quantity
mix
dilute exhaust gas mixture
out
outlet
PM
particulate matter
record
record
ref
reference quantity
rev
revolution
roll
dynamometer roll
s
settling
s
slip
s
stabilized
sat
saturated condition
SC03
air conditioning driving schedule
span
span quantity
sda
secondary dilution air
std
standard conditions
T
target
t
throat
test
test quantity
uncor
uncorrected quantity
w
weighted
zero
zero quantity

(e) Other acronyms and abbreviations.  This part uses the following additional abbreviations and acronyms:
                                    ACRONYM
                                    MEANING
A/C
air conditioning
AC17
air conditioning 2017 test interval
ALVW
adjusted loaded vehicle weight
ASME
American Society of Mechanical Engineers
CFR
Code of Federal Regulations
CFV
critical-flow venturi
CNG
compressed natural gas
CVS
constant-volume sampler
EPA
Environmental Protection Agency
ETW
equivalent test weight
EV
electric vehicle
FID
flame-ionization detector
FTP
Federal test procedure
GC
gas chromatograph
GEM
greenhouse gas emissions model
GHG
greenhouse gas (including CO2, N2O, and CH4)
GPS
global positioning system
GVWR
gross vehicle weight rating
HEV
hybrid electric vehicle, including plug-in hybrid electric vehicles
HFET
highway fuel economy test
HLDT
heavy light-duty truck
HPLC
high pressure liquid chromatography
IBR
incorporated by reference
LA-92
Los Angeles 1992 driving schedule
MDPV
medium-duty passenger vehicle
NIST
National Institute for Standards and Technology
NMC
nonmethane cutter
PDP
positive-displacement pump
PHEV
plug-in hybrid electric vehicle
PM
particulate matter
RESS
rechargeable energy storage system
ppm
parts per million
SAE
Society of Automotive Engineers
SC03
air conditioning driving schedule
SEA
selective enforcement audit
SFTP
supplemental federal test procedure
SI
International System of Units
SSV
subsonic venturi
UDDS
urban dynamometer driving schedule
US06
aggressive driving schedule
U.S.C.
United States Code
WWV
NIST radio station call sign

(f) This part uses the following densities of chemical species:
                                    SYMBOL
                                 QUANTITY[A,B]
                                    g/m[3]
                                    g/ft[3]
ρCH4
density of methane
666.905
18.8847
ρCH3OH
density of methanol
1332.02
37.7185
ρC2H5OH
C1-equivalent density of ethanol
957.559
27.1151
ρC2H4O
C1-equivalent density of acetaldehyde
915.658
25.9285
ρC3H8
density of propane
611.035
17.3026
ρC3H7OH
C1-equivalent density of propanol
832.74
23.5806
ρCO
density of carbon monoxide
1164.41
32.9725
ρCO2
density of carbon dioxide
1829.53
51.8064
ρHC-gas
effective density of hydrocarbon - gaseous fuel[c]
(see 3)
(see 3)
ρCH2O
density of formaldehyde
1248.21
35.3455
ρHC-liq
effective density of hydrocarbon - liquid fuel[d]
576.816
16.3336
ρNMHC-gas
effective density of nonmethane hydrocarbon - gaseous fuel[c]
(see 3)
(see 3)
ρNMHC-liq
effective density of nonmethane hydrocarbon - liquid fuel[d]
576.816
16.3336
ρNMHCE-gas
effective density of nonmethane equivalent hydrocarbon - gaseous fuel[c]
(see 3)
(see 3)
ρNMHCE-liq
effective density of nonmethane equivalent hydrocarbon - liquid fuel[d]
576.816
16.3336
ρNOx
effective density of oxides of nitrogen[e]
1912.5
54.156
ρN2O
density of nitrous oxide
1829.66
51.8103
ρTHC-liq
effective density of total hydrocarbon - liquid fuel[d]
576.816
16.3336
ρTHCE-liq
effective density of total equivalent hydrocarbon - liquid fuel[d]
576.816
16.3336
[a]Densities are given at 20 °C and 101.325 kPa.
[b]Densities for all hydrocarbon containing quantities are given in g/m[3]-carbon atom and g/ft[3]-carbon atom.
[c]The effective density for natural gas fuel and liquefied petroleum gas fuel are defined by an atomic hydrogen-to-carbon ratio, , of the hydrocarbon components of the test fuel.  ρHCgas = 41.57∙(12.011 + (∙1.008)).
[d]The effective density for gasoline and diesel fuel are defined by an atomic hydrogen-to-carbon ratio, , of 1.85.
[e]The effective density of NOx is defined by the molar mass of nitrogen dioxide, NO2.

*	*	*	*	*

PART 1068 -- GENERAL COMPLIANCE PROVISIONS FOR HIGHWAY, STATIONARY, AND NONROAD PROGRAMS
393. The authority statement for part 1068 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.

394. Amend §1068.1 by revising paragraph (a) and removing and reserving paragraph (d)(2) to n reads as follows:
§1068.1   Does this part apply to me?
(a) The provisions of this part apply to everyone with respect to the engine and equipment categories as described in this paragraph (a). They apply to everyone, including owners, operators, parts manufacturers, and persons performing maintenance. Where we identify an engine category, the provisions of this part also apply with respect to the equipment using such engines. This part 1068 applies to different engine and equipment categories as follows:
   (1) This part 1068 applies to motor vehicles we regulate under 40 CFR part 86, subpart S, to the extent and in the manner specified in 40 CFR parts 85 and 86.
   (2) This part 1068 applies for heavy-duty motor vehicles we regulate under 40 CFR part 1037, subject to the provisions of 40 CFR parts 85 and 1037. This includes trailers. This part 1068 applies to other heavy-duty motor vehicles and motor vehicle engines to the extent and in the manner specified in 40 CFR parts 85, 86, and 1036.
   (3) This part 1068 applies to highway motorcycles we regulate under 40 CFR part 86, subparts E and F, to the extent and in the manner specified in 40 CFR parts 85 and 86.
   (4) This part 1068 applies to aircraft we regulate under 40 CFR part 87 to the extent and in the manner specified in 40 CFR part 87.
   (5) This part 1068 applies for locomotives that are subject to the provisions of 40 CFR part 1033. This part 1068 does not apply for locomotives or locomotive engines that were originally manufactured before July 7, 2008, and that have not been remanufactured on or after July 7, 2008.
   (6) This part 1068 applies for land-based nonroad compression-ignition engines that are subject to the provisions of 40 CFR part 1039.
   (7) This part 1068 applies for stationary compression-ignition engines certified using the provisions of 40 CFR parts 1039 and 1042 as described in 40 CFR part 60, subpart IIII.
   (8) This part 1068 applies for marine compression-ignition engines that are subject to the provisions of 40 CFR part 1042.
   (9) This part 1068 applies for marine spark-ignition engines that are subject to the provisions of 40 CFR part 1045.
   (10) This part 1068 applies for large nonroad spark-ignition engines that are subject to the provisions of 40 CFR part 1048.
   (11) This part 1068 applies for stationary spark-ignition engines certified using the provisions of 40 CFR part 1048 or part 1054, as described in 40 CFR part 60, subpart JJJJ.
   (12) This part 1068 applies for recreational engines and vehicles, including snowmobiles, off-highway motorcycles, and all-terrain vehicles that are subject to the provisions of 40 CFR part 1051.
   (13) This part applies for small nonroad spark-ignition engines that are subject to the provisions of 40 CFR part 1054.
   (14) This part applies for fuel-system components installed in nonroad equipment powered by volatile liquid fuels that are subject to the provisions of 40 CFR part 1060.
*	*	*	*	*

395. Amend §1068.10 by revising the section heading and paragraphs (b) and (c) to read as follows:
§1068.10   Confidential business information.
*	*	*	*	*
(b) We will store your confidential business information as described in 40 CFR part 2. Also, we will disclose it only as specified in 40 CFR part 2. This applies both to any information you send us and to any information we collect from inspections, audits, or other site visits.
(c) If you send us a second copy without the confidential business information, we will assume it contains nothing confidential whenever we need to release information from it.
*	*	*	*	*

396. Amend §1068.240 by revising paragraphs (b)(6), (c)(1), and (c)(3) to read as follows:
§1068.240   Exempting new replacement engines.
*	*	*	*	*
(b) 	*	*	*
(6) Engines exempt under this paragraph (b) may not be introduced into U.S. commerce before you make the determinations under paragraph (b)(2) of this section, except as specified in this paragraph (b)(6). We may waive this restriction for engines identified under paragraph (c)(5) of this section that you ship to a distributor. Where we waive this restriction, you must take steps to ensure that the engine is installed consistent with the requirements of this paragraph (b). For example, at a minimum you must report to us annually whether engines we allowed you to ship to a distributor under this paragraph (b)(6) have been placed into service or remain in inventory. After an engine is placed into service, your report must describe how the engine was installed consistent with the requirements of this paragraph (b). Send these reports to the Designated Compliance Officer by the deadlines we specify.
(c)	*	*	*
(1) You may produce a limited number of replacement engines under this paragraph (c) representing 0.5 percent of your annual production volumes for each category and subcategory of engines identified in Table 1 to this section or five engines for each category and subcategory, whichever is greater. Calculate this number by multiplying your annual U.S.-directed production volume by 0.005 (or 0.01 through 2013) and rounding to the nearest whole number. Determine the appropriate production volume by identifying the highest total annual U.S.-directed production volume of engines from the previous three model years for all your certified engines from each category or subcategory identified in Table 1 to this section, as applicable. In unusual circumstances, you may ask us to base your production limits on U.S.-directed production volume for a model year more than three years prior. You may include stationary engines and exempted engines as part of your U.S.-directed production volume. Include U.S.-directed engines produced by any affiliated companies and those from any other companies you license to produce engines for you.
*	*	*	*	*
(3) Send the Designated Compliance Officer a report by September 30 of the year following any year in which you produced exempted replacement engines under this paragraph (c).
(i) In your report include the total number of replacement engines you produce under this paragraph (c) for each category or subcategory, as appropriate, and the corresponding total production volumes determined under paragraph (c)(1) of this section. If you send us a report under this paragraph (c)(3), you must also include the total number of complete and partially complete replacement engines you produced under paragraphs (b) and (e) of this section (including any replacement marine engines subject to reporting under 40 CFR 1042.615).
(ii) Count exempt engines as tracked under paragraph (b) of this section only if you meet all the requirements and conditions that apply under paragraph (b)(2) of this section by the due date for the annual report. In the annual report you must identify any replaced engines from the previous year that you were not able to recover by the due date for the annual report. Continue to report those engines in later reports until you recover the replaced engines. If any replaced engine is not recovered for the fifth annual report following the production report, treat this as an untracked replacement in the fifth annual report for the preceding year.
(iii) You may include the information required under this paragraph (c)(3) in production reports required under the standard-setting part.
*	*	*	*	*

PART 1074 -- PREEMPTION OF STATE STANDARDS AND PROCEDURES FOR WAIVER OF FEDERAL PREEMPTION FOR NONROAD ENGINES AND NONROAD VEHICLES
397. The authority statement for part 1074 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.

398. Add Appendix I to subpart A to read as follows:
Appendix I to subpart A of part 1074 -- State Regulation of the Use and Operation of Nonroad Internal Combustion Engines.
(a) This appendix describes EPA's interpretation of the Clean Air Act regarding the authority of states to regulate the use and operation of nonroad engines.
(b) EPA believes that states are not precluded under 42 U.S.C. 7543 from regulating the use and operation of nonroad engines, such as regulations on hours of usage, daily mass emission limits, or sulfur limits on fuel; nor are permits regulating such operations precluded, once the engine is no longer new. EPA believes that states are precluded from requiring retrofitting of used nonroad engines except that states are permitted to adopt and enforce any such retrofitting requirements identical to California requirements which have been authorized by EPA under 42 U.S.C. 7543.