Comments by "Animal Farm" (@animalfarm7467) on "Mazda создает Грааль бензиновых двигателей - HCCI SkyActiv-X" video.

Thanks for the info but there is one thing I don't understand. I understand why a spark plug is used to control combustion timing when the engine is cold but how could one depend on a spark plug to control the combustion timing of a hot engine? Surely the temperature of compression plus the temperature of the cylinder environment in a heavily loaded engine would produce preignition resulting again in uncontrollable combustion timing and potential engine knock. So how does one control the combustion ignition timing when the engine is running hot? You certainly couldn't leave it up to a spark plug. Does the engine management system also reduce the effective compression ratio when the engine is heavily loaded? Seems a little redundant if it does.
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