40 CFR §600.113-12

1. (a)Calculate the FTP fuel economy as follows:
   1. (1)Calculate the weighted grams/mile values for the FTP test for CO2, HC, and CO, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 as specified in 40 CFR 1066.605. Measure and record the test fuel's properties as specified in paragraph (f) of this section.
   2. (2)Calculate separately the grams/mile values for the cold transient phase, stabilized phase and hot transient phase of the FTP test. For vehicles with more than one source of propulsion energy, one of which is a rechargeable energy storage system, or vehicles with special features that the Administrator determines may have a rechargeable energy source, whose charge can vary during the test, calculate separately the grams/mile values for the cold transient phase, stabilized phase, hot transient phase and hot stabilized phase of the FTP test.
2. (b)Calculate the HFET fuel economy as follows:
   1. (1)Calculate the mass values for the highway fuel economy test for HC, CO, and CO2, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 as specified in 40 CFR 1066.605. Measure and record the test fuel's properties as specified in paragraph (f) of this section.
   2. (2)Calculate the grams/mile values for the highway fuel economy test for HC, CO, and CO2, and where applicable CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 by dividing the mass values obtained in paragraph (b)(1) of this section, by the actual driving distance, measured in miles, as specified in 40 CFR 1066.840.
3. (c)Calculate the cold temperature FTP fuel economy as follows:
   1. (1)Calculate the weighted grams/mile values for the cold temperature FTP test for HC, CO, and CO2, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 as specified in 40 CFR 1066.605.
   2. (2)Calculate separately the grams/mile values for the cold transient phase, stabilized phase and hot transient phase of the cold temperature FTP test as specified in 40 CFR 1066.605.
   3. (3)Measure and record the test fuel's properties as specified in paragraph (f) of this section.
4. (d)Calculate the US06 fuel economy as follows:
   1. (1)Calculate the total grams/mile values for the US06 test for HC, CO, and CO2, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 as specified in 40 CFR 1066.605.
   2. (2)Calculate separately the grams/mile values for HC, CO, and CO2, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4, for both the US06 City phase and the US06 Highway phase of the US06 test as specified in 40 CFR 1066.605 and 1066.831. In lieu of directly measuring the emissions of the separate city and highway phases of the US06 test according to the provisions of 40 CFR 1066.831, the manufacturer may optionally, with the advance approval of the Administrator and using good engineering judgment, analytically determine the grams/mile values for the city and highway phases of the US06 test. To analytically determine US06 City and US06 Highway phase emission results, the manufacturer shall multiply the US06 total grams/mile values determined in paragraph (d)(1) of this section by the estimated proportion of fuel use for the city and highway phases relative to the total US06 fuel use. The manufacturer may estimate the proportion of fuel use for the US06 City and US06 Highway phases by using modal CO2, HC, and CO emissions data, or by using appropriate OBD data (e.g., fuel flow rate in grams of fuel per second), or another method approved by the Administrator.
   3. (3)Measure and record the test fuel's properties as specified in paragraph (f) of this section.
5. (e)Calculate the SC03 fuel economy as follows:
   1. (1)Calculate the grams/mile values for the SC03 test for HC, CO, and CO2, and where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4 as specified in 40 CFR 1066.605.
   2. (2)Measure and record the test fuel's properties as specified in paragraph (f) of this section.
6. (f)Analyze and determine fuel properties as follows:
   1. (1)Gasoline test fuel properties shall be determined by analysis of a fuel sample taken from the fuel supply. A sample shall be taken after each addition of fresh fuel to the fuel supply. Additionally, the fuel shall be resampled once a month to account for any fuel property changes during storage. Less frequent resampling may be permitted if EPA concludes, on the basis of manufacturer-supplied data, that the properties of test fuel in the manufacturer's storage facility will remain stable for a period longer than one month. The fuel samples shall be analyzed to determine fuel properties as follows for neat gasoline (E0) and for a low-level ethanol-gasoline blend (E10):
      1. (i)Specific gravity. Determine specific gravity using ASTM D4052 (incorporated by reference, see § 600.011). Note that ASTM D4052 refers to specific gravity as relative density.
      2. (ii)Carbon mass fraction.
         1. (A)For E0, determine hydrogen mass percent using ASTM D3343 (incorporated by reference, see § 600.011), then determine carbon mass fraction as CMF = 1−0.01 × hydrogen mass percent.
         2. (B)For E10, determine carbon mass fraction of test fuel, CMFf, using the following equation, rounded to three decimal places:
      3. (iii)Net heat of combustion.
         1. (A)For E0, determine net heat of combustion in MJ/kg using ASTM D3338/D3338M (incorporated by reference, see § 600.011).
         2. (B)For E10, determine net heat of combustion, NHCf, in MJ/kg using the following equation, rounding the result to the nearest whole number:
   2. (2)Methanol test fuel shall be analyzed to determine the following fuel properties:
      1. (i)Specific gravity using ASTM D 1298 (incorporated by reference in § 600.011). You may determine specific gravity for the blend, or you may determine specific gravity for the gasoline and methanol fuel components separately before combining the results using the following equation:
      2. (ii)
         1. (A)Carbon weight fraction using the following equation:
         2. (B)Upon the approval of the Administrator, other procedures to measure the carbon weight fraction of the fuel blend may be used if the manufacturer can show that the procedures are superior to or equally as accurate as those specified in this paragraph (f)(2)(ii).
   3. (3)Natural gas test fuel shall be analyzed to determine the following fuel properties:
      1. (i)Fuel composition measured using ASTM D 1945 (incorporated by reference in § 600.011).
      2. (ii)Specific gravity measured as based on fuel composition per ASTM D 1945 (incorporated by reference in § 600.011).
      3. (iii)Carbon weight fraction, based on the carbon contained only in the hydrocarbon constituents of the fuel. This equals the weight of carbon in the hydrocarbon constituents divided by the total weight of fuel.
      4. (iv)Carbon weight fraction of the fuel, which equals the total weight of carbon in the fuel (i.e., includes carbon contained in hydrocarbons and in CO2) divided by the total weight of fuel.
   4. (4)Ethanol test fuel shall be analyzed to determine the following fuel properties:
      1. (i)Specific gravity using ASTM D 1298 (incorporated by reference in § 600.011). You may determine specific gravity for the blend, or you may determine specific gravity for the gasoline and methanol fuel components separately before combining the results using the following equation:
      2. (ii)
         1. (A)Carbon weight fraction using the following equation:
         2. (B)Upon the approval of the Administrator, other procedures to measure the carbon weight fraction of the fuel blend may be used if the manufacturer can show that the procedures are superior to or equally as accurate as those specified in this paragraph (f)(4)(ii).
7. (g)Calculate separate FTP, highway, US06, SC03 and Cold temperature FTP fuel economy values from the grams/mile values for total HC, CO, CO2 and, where applicable, CH3OH, C2H5OH, C2H4O, HCHO, NMHC, N2O, and CH4, and the test fuel's specific gravity, carbon weight fraction, net heating value, and additionally for natural gas, the test fuel's composition.
   1. (1)Emission values for fuel economy calculations. The emission values (obtained per paragraph (a) through (e) of this section, as applicable) used in the calculations of fuel economy in this section shall be rounded in accordance with § 86.1837 of this chapter. The CO2 values (obtained per this section, as applicable) used in each calculation of fuel economy in this section shall be rounded to the nearest gram/mile.
   2. (2)[Reserved]
   3. (3)The specific gravity and the carbon mass fraction (obtained per paragraph (f) of this section) shall be recorded using three places to the right of the decimal point. Net heat of combustion shall be recorded using three places to the right of the decimal point if expressed in MJ/kg, or the nearest whole number if expressed in Btu/lb.
8. (h)
   1. (1)For gasoline-fueled automobiles tested on a test fuel specified in § 86.113 of this chapter, the fuel economy in miles per gallon is to be calculated using the following equation and rounded to the nearest 0.1 miles per gallon:
   2. (2)[Reserved]
      1. (i)
         1. (1)For diesel-fueled automobiles, calculate the fuel economy in miles per gallon of diesel fuel by dividing 2778 by the sum of three terms and rounding the quotient to the nearest 0.1 mile per gallon:
            1. (i)
               1. (A)0.866 multiplied by HC (in grams/miles as obtained in paragraph (g)(1) of this section), or
               2. (B)Zero, in the case of cold FTP diesel tests for which HC was not collected, as permitted in § 600.113-08(c);
            2. (ii)0.429 multiplied by CO (in grams/mile as obtained in paragraph (g)(1) of this section); and
            3. (iii)0.273 multiplied by CO2 (in grams/mile as obtained in paragraph (g)(1) of this section).
         2. (2)[Reserved]
9. (j)
   1. (1)For methanol-fueled automobiles and automobiles designed to operate on mixtures of gasoline and methanol, the fuel economy in miles per gallon of methanol is to be calculated using the following equation:
   2. (2)[Reserved]
10. (k)
    1. (1)For automobiles fueled with natural gas and automobiles designed to operate on gasoline and natural gas, the fuel economy in miles per gallon of natural gas is to be calculated using the following equation:
    2. (2)[Reserved]
11. (l)
    1. (1)For ethanol-fueled automobiles and automobiles designed to operate on mixtures of gasoline and ethanol, the fuel economy in miles per gallon of ethanol is to be calculated using the following equation:
    2. (2)[Reserved]
12. (m)
    1. (1)For automobiles fueled with liquefied petroleum gas and automobiles designed to operate on gasoline and liquefied petroleum gas, the fuel economy in miles per gallon of liquefied petroleum gas is to be calculated using the following equation:
    2. (2)[Reserved]
13. (n)Manufacturers may use a value of 0 grams CO2 per mile to represent the emissions of electric vehicles and the electric operation of plug-in hybrid electric vehicles derived from electricity generated from sources that are not onboard the vehicle.
14. (o)
    1. (1)For testing with E10, calculate fuel economy using the following equation, rounded to the nearest 0.1 miles per gallon:
    2. (2)[Reserved]
15. (p)Equations for fuels other than those specified in this section may be used with advance EPA approval. Alternate calculation methods for fuel economy may be used in lieu of the methods described in this section if shown to yield equivalent or superior results and if approved in advance by the Administrator.