[Code of Federal Regulations]
[Title 40, Volume 29]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR600.113-78]

[Page 898-899]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 600_FUEL ECONOMY OF MOTOR VEHICLES--Table of Contents
 
    Subpart B_Fuel Economy Regulations for 1978 and Later Model Year 
                       Automobiles_Test Procedures
 
Sec. 600.113-78  Fuel economy calculations.

    The calculations of vehicle fuel economy values require the weighted 
grams/mile values for HC, CO, and CO2 for the city fuel 
economy test and the grams/mile values for HC, CO, and CO2 
for the highway fuel economy test. The city and highway fuel economy 
values must be calculated by the procedures of this section. A sample 
calculation appears in appendix II to this part.
    (a) Calculate the weighted grams/mile values for the city fuel 
economy test for HC, CO, and CO2 as specified in Sec. 86.144 
of this chapter.
    (b)(1) Calculate the mass values for the highway fuel economy test 
for HC, CO, and CO2 as specified in paragraph (b) of Sec. 
86.144 of this chapter.
    (2) Calculate the grams/mile values for the highway test for HC, CO, 
and CO2 by dividing the mass values obtained in (b)(1) by the 
actual distance traveled, measured in miles, as specified in paragraph 
(h) of Sec. 86.135 of this chapter.
    (c) Calculate the city fuel economy and highway fuel economy from 
grams/mile values for HC, CO, and CO2. The emission values 
(obtained per paragraph (a) or (b) as applicable) used in each 
calculation of this section shall be rounded in accordance with Sec. 
86.079-

[[Page 899]]

26(a)(6)(ii). The CO2 values (obtained per paragraph (a) or 
(b) of this section as applicable) used in each calculation in this 
section are rounded to the nearest gram/mile.
    (d) For gasoline-fueled automobiles, calculate the fuel economy in 
miles per gallon of gasoline by dividing 2421 by the sum of three terms:
    (1) 0.866 multiplied by HC (in grams/miles as obtained in paragraph 
(c)),
    (2) 0.429 multiplied by CO (in grams/miles as obtained in paragraph 
(c), and
    (3) 0.273 multiplied by CO2 (in grams/mile as obtained in 
paragraph (c) of this section).

Round to quotient to the nearest 0.1 mile per gallon.
    (e) For diesel powered automobiles, calculate the fuel economy in 
miles per gallon of diesel fuel by dividing 2778 by the sum of three 
terms:
    (1) 0.866 multiplied by HC (in grams/mile as obtained in paragraph 
(c) of this section),
    (2) 0.429 multiplied by CO (in grams/mile as obtained in paragraph 
(c)), and
    (3) 0.273 multiplied by CO2 (in grams/mile as obtained in 
paragraph (c)).

Round the quotient to the nearest 0.1 mile per gallon.

[42 FR 45657, Sept. 12, 1977, as amended at 43 FR 52929, Nov. 14, 1978]