Winter chills limit range of the Tesla Model S electric car

Re:Winter chills limit range of the Tesla Model S electric car by ScottBurson on Sunday February 17, 2013 @02:05AM (#5234461)

I think the peak is actually closer to 45 for most gasoline-driven cars. It depends on aerodynamics, though. For a big SUV it might be 35. I suppose it could be as high as 55 for a small, highly aerodynamic car.

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Re:Winter chills limit range of the Tesla Model S electric car by Someone on Sunday February 17, 2013 @03:47AM (#5234624)

Aerodynamics and engine/drive train design.

Aerodynamically, the slower you drive, the more efficient you drive. The exact curve will depend on air pressure, amount of moisture in the air, etc.

For the engine, it is more complicated. You will want to keep its temperature and rpm at ideal levels. rpm and the gearing in the drive train determine what speed(s) that corresponds to (I guess drive train losses will depend a bit on the gearing, too, but that effect should be minimal)

For the two combined, this gets really complicated. Do you drive at the engine-optimal 45 or does the gain due to lower speed offset the loss in engine efficiency at 44? If 44 is more efficient now, will it stay that when it starts to rain? When you enter a different road surface? When your tires heat up and tire pressure increases slightly? When you have a window open?

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles#Spe... shows how convoluted this can get.

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