Quote:
Originally Posted by dcb
Someone explain to me why mpge is even necessary?
What is so terrible about listing mpg and kw/mile separately?
Mpge is a solution in search of a problem, while making new problems in the process.
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IMHO, for a BEV such as a Leaf, or an iMiEV, or my Citicar, wh/mi is an appropriate measurement. I include my wh/mi in my 'garage' posts, but the system here is geared towards fossil fueled vehicles, thus the odd 159 MPG number by my vehicle. The MPGe rating for my EV is somewhat disingenuous. Perhaps there will be a site change here in the future to choose between wh/mi and MPG.
'Combined mileage' numbers, such as the 129 MPG number used by an auto magazine for a Volt test, and a 80 MPG number used in a plug-in Prius test, are very misleading and should not be used - Does a driver only drive 5 miles a day? Does a driver commute 200 miles a day? What happens to the combined mileage number when a plug-in hybrid can't be plugged in for some part of a particular trip?
The MPGe rating comes into place with plug-in hybrids. Comparing a Volt with a Plug-in Prius (both are basically plug-in hybrids; neither is an EV) an MPGe number would have more significance - perhaps a depleted-pack MPG over electric-only wh/mi.
As an example, a Volt may get an MPGe number along the lines of 40/266 (MPG depleted over wh/mi) and a plug-in Prius may get 50/220. These numbers are speculative, but close based on some auto magazine tests.
For an efficient plug-in hybrid, one would look for a high first number and a low second number.