Appendix A to Part 474 - —Sample Petroleum-Equivalent Fuel Economy Calculations

Appendix A to Part 474—Sample Petroleum-Equivalent Fuel Economy Calculations

Example 1: Battery Electric Vehicle (BEV)

A battery electric vehicle is tested in accordance with Environmental Protection Agency procedures and is found to have an Urban Dynamometer Driving Schedule energy consumption value of 265 Watt-hours per mile and a Highway Fuel Economy Driving Schedule energy consumption value of 220 Watt-hours per mile. The vehicle is not equipped with any petroleum-powered accessories. The combined electrical energy consumption value is determined by averaging the Urban Dynamometer Driving Schedule energy consumption value and the Highway Fuel Economy Driving Schedule energy consumption value using weighting factors of 55 percent urban, and 45 percent highway:

combined electrical energy consumption value = (0.55 * urban) + (0.45 * highway) = (0.55 * 265) + (0.45 * 220) = 244.75 Wh/mile

The petroleum-equivalent fuel economy is:

PEF ÷ combined electrical energy consumption value

Thus, fuel economy for the example vehicle in MY 2030 would be:

where MPGe is miles per gallon equivalent.

Example 2: Plug-In Hybrid Electric Vehicle

A plug-in hybrid electric vehicle is tested in accordance with Environmental Protection Agency procedures and is found to have an Urban Dynamometer Driving Schedule energy consumption value of 265 Watt-hours per mile and a Highway Fuel Economy Driving Schedule energy consumption value of 220 Watt-hours per mile in charge depleting mode, a combined gasoline fuel economy of 50.0 miles per gallon in charge sustaining mode, and an all-electric range corresponding to a percentage utilization of 60 percent travel on electricity and 40 percent travel on gasoline.

The combined electrical energy consumption value is determined by averaging the Urban Dynamometer Driving Schedule energy consumption value and the Highway Fuel Economy Driving Schedule energy consumption value using weighting factors of 55 percent urban, and 45 percent highway to be 244.75 Wh/mile, which corresponds to 118.47 miles/gal equivalent as shown above for a BEV (using the MY 2030-and-beyond PEF value of 28,997 Wh/gal).

The PHEV fuel economy is calculated by dividing one by the sum of the percentage utilization for petroleum and electricity divided by their respective fuel economy.

In this case:

[89 FR 22059, Mar. 29, 2024]