Re: [Phys-l] Hybrid mileage

[Jack Uretsky <jlu@hep.anl.gov>]

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.
						Regards,
							Jack

"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
> > temperature.
>
> ???
>
> 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
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