High MPG

[Danny Barrett]

I agree about the ceramic engines, but aren't they a bit expensive???


>The efficiency, in terms of fuel used for power generated, of an internal
>combustion engine has to do with expansion ratio, combustion temperature and
>pumping loss.  2 valve, 4 valve, pushrod, OHC, etc have little or no effect
>on efficiency.  High winding multi valve engines get more power per
>displacement but not necessarily more power per weight or cost.  Maybe you
>con't like pushrods, or they are aesthetically displeasing to you but they
>are certainly not less efficient.
>
>A gasoline engine wastes only 60% of the energy in gasoline when operated at
>full throttle.  It wastes 80% at part throttle where it operates like a big
>vacuum pump with a leak and it wastes 100% at idle.  Multi-valve and
>overhead cams don't change these numbers.
>
>Gas turbines, steam, rotary, etc generally do worse.  The road to
>improvement is paved with reduced heat loss from exhaust and cooling.
>Ceramic parts which operate without cooling and greater expansion ratios can
>reduce this energy wastage.  None of which has anything to do with pushrods.
>
>Gary Derian <gderian at cybergate.net>
>
><snip>
>
>>I think pushrod engines waste something in the neighborhood of 80% of the
>>available power in the gasoline.
>>
>>Frederic Breitwieser
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