- #36
jim hardy
Science Advisor
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poe said:What you have not gotten yet is that an automotive engine which lacks a throttle drops in efficiency under light load also, ...
That would be in the US only a handful of hybrid vehicle engines and diesels.
Mazda recently announced a HCCI gasoline engine for 2019 but details are sparse.
This source describes it as "Throttle-less"
https://www.thoughtco.com/hcci-homogeneous-charge-compression-ignition-85588
- perhaps that's why the electric supercharger which is presumably for light load cruising.Throttleless induction system eliminates frictional pumping losses incurred in traditional (throttle body) spark engines.
physea said:It is known that automotive engine efficiency (ie. fuel efficiency) is maximum at a specific range of medium loads. If we go higher than this range, the efficiency drops. If we go lower than these loads, the efficiency drops as well.
Do we know the reasons for that? I am particularly interested in the low load efficiency decrease, but high load would be interesting as well.
Thanks!
Tone of original question suggests physea is not a 'subject matter expert' . One tries to provide answers not too distant from questioner's apparent level .
Regards -
old jim