Federal regulations · Through 2026-08-25 · Newer source version available

40 CFR Appendix II to Part 600: Appendix II to Part 600—Sample Fuel Economy Calculations

(a) This sample fuel economy calculation is applicable to 1978 through 1987 model year automobiles.
(1) Assume that a gasoline-fueled vehicle was tested by the Federal Emission Test Procedure and the following results were calculated:
HC = .139 grams/mile
CO = 1.59 grams/mile
CO2 = 317 grams/mile
According to the procedure in § 600.113-78, the city fuel economy or MPGc, for the vehicle may be calculated by substituting the HC, CO, and CO2 grams/mile values into the following equation.
MPGc = 27.7
(2) Assume that the same vehicle was tested by the Federal Highway Fuel Economy Test Procedure and calculation similar to that shown in paragraph (a) by this appendix resulted in a highway fuel economy or MPGh of 36.9. According to the procedure in § 600.113, the combined fuel economy (called MPGc/h) for the vehicle may be calculated by substituting the city and highway fuel economy values into the following equation:
(b) This sample fuel economy calculation is applicable to 1988 and later model year automobiles.
(1) Assume that a gasoline-fueled vehicle was tested by the Federal Emission Test Procedure and the following results were calculated:
HC = .139 grams/mile.
CO = 1.59 grams/mile.
CO2 = 317 grams/mile.
(2) Assume that the test fuel used for this test had the following properties:
SG = 0.745.
CWF = 0.868.
NHV = 18,478 Btu/lb.
(3) According to the procedure in § 600.113-08, the city fuel economy or MPGc, for the vehicle may be calculated by substituting the HC, CO, and CO2 gram/mile values and the SG, CWF, and NHV values into the following equation:
MPGc = (5174 × 10 4 × CWF × SG) / [((CWF × HC) + (0.429 × CO + (0.273 × CO2)) ((0.6 × SG × NHV) + 5471)]
Example:
MPGc = (5174 × 10 4 × 0.868 × 0.745) / [(0.868 × .139 + 0.429 × 1.59 + 0.273 × 317)(0.6 × 0.745 × 18478 + 5471)]
MPGc = 27.9
(4) Assume that the same vehicle was tested by the Federal Highway Fuel Economy Test Procedure and a calculation similar to that shown in (b)(3) of this section resulted in a highway fuel economy of MPGh of 36.9. According to the procedure in § 600.210-08(c) or § 600.210-12(c), the combined fuel economy (called MPGcomb) for the vehicle may be calculated by substituting the city and highway fuel economy values into the following equation:

Where this section sits in the code

Title 40—Protection of Environment
CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY
SUBCHAPTER Q—ENERGY POLICY
PART 600—FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES

(a) This sample fuel economy calculation is applicable to 1978 through 1987 model year automobiles.

(1) Assume that a gasoline-fueled vehicle was tested by the Federal Emission Test Procedure and the following results were calculated:

HC = .139 grams/mile

CO = 1.59 grams/mile

CO2 = 317 grams/mile

According to the procedure in § 600.113-78, the city fuel economy or MPGc, for the vehicle may be calculated by substituting the HC, CO, and CO2 grams/mile values into the following equation.

MPGc = 27.7

(2) Assume that the same vehicle was tested by the Federal Highway Fuel Economy Test Procedure and calculation similar to that shown in paragraph (a) by this appendix resulted in a highway fuel economy or MPGh of 36.9. According to the procedure in § 600.113, the combined fuel economy (called MPGc/h) for the vehicle may be calculated by substituting the city and highway fuel economy values into the following equation:

(b) This sample fuel economy calculation is applicable to 1988 and later model year automobiles.

(1) Assume that a gasoline-fueled vehicle was tested by the Federal Emission Test Procedure and the following results were calculated:

HC = .139 grams/mile.

CO = 1.59 grams/mile.

CO2 = 317 grams/mile.

(2) Assume that the test fuel used for this test had the following properties:

SG = 0.745.

CWF = 0.868.

NHV = 18,478 Btu/lb.

(3) According to the procedure in § 600.113-08, the city fuel economy or MPGc, for the vehicle may be calculated by substituting the HC, CO, and CO2 gram/mile values and the SG, CWF, and NHV values into the following equation:

MPGc = (5174 × 10 4 × CWF × SG) / [((CWF × HC) + (0.429 × CO + (0.273 × CO2)) ((0.6 × SG × NHV) + 5471)]

Example:

MPGc = (5174 × 10 4 × 0.868 × 0.745) / [(0.868 × .139 + 0.429 × 1.59 + 0.273 × 317)(0.6 × 0.745 × 18478 + 5471)]

MPGc = 27.9

(4) Assume that the same vehicle was tested by the Federal Highway Fuel Economy Test Procedure and a calculation similar to that shown in (b)(3) of this section resulted in a highway fuel economy of MPGh of 36.9. According to the procedure in § 600.210-08(c) or § 600.210-12(c), the combined fuel economy (called MPGcomb) for the vehicle may be calculated by substituting the city and highway fuel economy values into the following equation:

Collected 2026-08-27T02:26:04Z. Source file · JSON

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