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Old 12-14-2010, 10:05 AM   #232 (permalink)
NeilBlanchard
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Hi,

Quote:
Originally Posted by autoteach View Post
So, if the EPA uses mpg for both, but uses mpge for electric, one could conclude that they do not account for the energy density difference. That is their efficiency at constant operation, not using engine stop/start tech.
That's what I figured. According to the X-Prize MPGe spreadsheet, diesel has to be multiplied by 0.9 to be MPGe; or 1 gallon of diesel = 1.12 gallons of gasoline. The Wikipedia page linked earlier says diesel MPG needs to be multiplied by 0.83660305694757009 (!!) to be MPGe.

That makes it seem like most of the FE for diesels is due to the higher energy level of diesel itself, and only a little is because the engines are more efficient.
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