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Old 12-23-2011, 12:10 PM   #19 (permalink)
drmiller100
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Quote:
Originally Posted by Old Mechanic View Post
Lets assume that throttle restriction is energy costly (it is), when an engine uses a throttle plate to control air flow into the engine. I guess the question is can you extract enough energy from the restriction to make it worthwhile?

I never really thought it was that much of an energy loss since the most pressure differential you can have is 14.7 PSI (give or take depending on atmospheric pressure).
Would any system be sufficient to do the job of the alternator?

regards
Mech
throttle pumping loss is apparently measurable, and noticable. If you have a manual transmission, you can feel it yourself - coasting down the road, turn off the ignition and note your rate of deceleration. Then floor the throttle - you should feel deceleration lessoning.
This is the reason diesel engines have such crappy compression braking with out "jake brakes" and the like.
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