Appendix to Part 474 - Sample Petroleum-Equivalent Fuel Economy Calculations
10:3.0.1.4.32.0.90.6.72 :
Appendix to Part 474 - Sample Petroleum-Equivalent Fuel Economy
Calculations Example 1:An 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 Since the vehicle does not have any
petroleum-powered accessories installed, the value of the petroleum
equivalency factor is 82,049 Watt-hours per gallon, and the
petroleum-equivalent fuel economy is: (82,049 Wh/gal) (244.75
Wh/mile) = 335.24 mpg Example 2:The vehicle from Example 1 is
equipped with an optional diesel-fired cabin heater/defroster. For
the purposes of this example, it is assumed that the electrical
efficiency of the vehicle is unaffected.
Since the vehicle has a petroleum-powered accessory installed,
the value of the petroleum equivalency factor is 73,844 Watt-hours
per gallon, and the petroleum-equivalent fuel economy is:
(73,844 Wh/gal) (244.75 Wh/mile) = 301.71 mpg