Four-stroke engine

internal combustion engine type

The four-stroke engine is an internal combustion engine. The four strokes are:

Stroke Alias Piston Intake valve Exhaust valve
intake suck opens, sucks in air + fuel open closed
compression squeeze closes, compressing the air + fuel closed closed
combustion bang opens, because air + fuel combust, expanding gas in cylinder closed closed
exhaust blow closes, blowing out the used gasses closed open
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