This entry was posted by Wednesday, 12 August, 2009
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Automotive Engineering: 230 Delusion Per Mile
General Motors just announced a remarkable fact about its new “Chevy Volt”. Fuel economy of two hundred thirty unbelievable miles per gallon.
As a Plug-in Hybrid, the Volt charges up overnight and then gives you a “free” ride of as much as 40 miles before it has to switch over to its gasoline engine. Factoring this in, General Motors appears to think that the typical owner of a Chevy Volt will get 230 mile per gallon (looking at it in terms of the “gas in the tank”).
..electricity isn’t free energy. It comes (mainly) from fossil fuels. And the diesel engine at the power plant has its own carnot cycle and the power lines have transmission losses. If you figure out the EQUIVALENT mpg including that of the fuel being burned up back at the powerplant (oh yeah!), you’re gonna get a lot more realistic number for fuel economy.
The Volt is, no doubt, a significant vehicle and an efficient one and ScienceAintSoBad wishes General Motors Corporation much luck with the venture.
Not even mad that it’s checking to see if we’re paying attention.
We are.
ScienceAin’tSoBadRating = 1

3 Responses to “Automotive”

  1. Anonymous

    But at least this opens the door to getting cars partially off of fossil fuels, since the electricity could come from other sources.

  2. Anonymous

    A couple points:

    1. Diesel fuel is not used at electric power plants. Coal yes, Diesel no. Don't forget nuclear and other sources to contribute to the grid.

    2. The charge needed to charge the battery overnight is significantly more efficient and carbon-footprint friendly than burning gasoline to move the vehicle the same distances.

    3. The 230 MPG is according to a draft memo by the EPA to try to figure out how to rate this particular type of vehicle. GM is merely using their draft proposal. There should probably be some kind of overall energy consumption number listed, but until the EPA comes up with that, we will just have to wait and see what it is.

  3. Anonymous

    The article refers to "fossil fuels". Coal is very much a fossil fuel.

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