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Re: [Phys-l] Hybrid mileage

Hi all-
The data are insufficient. For example, if, in winter, you let the car sit and warm up for a bit before driving, your winter mi/gal would be reduced.
A more complete analysis would require comparison - summer v winter - of miles driven, driving times, and fuel consumption. This would lead to possible systematic differences (or uncertainties) in your data.

"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn Valley

On Tue, 5 Jan 2010, Stefan Jeglinski wrote:

Part of the loss of mpg in the winter for a hybrid (and all other
cars) is that the engine has to run longer to bring the catalytic
converter up to temperature to meet emission reduction requirements.
And the engine has to run more to keep the converter up to


In a non-hybrid anyway, you run the engine for however long you want,
whether the CC is up to temp or not. Are you saying the temp of the
CC affects the gas useage? And/or, are engines tuned to run at
slightly higher rpm to provide extra energy to keep the CC at temp?

I don't quite get the full extent of your description. If you could
describe things in terms of energy generated/expended rather that
"engine running longer/more" it would help.

Stefan Jeglinski
Forum for Physics Educators