compression stroke: internal-combustion engine

An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust. As the piston moves during each stroke, it turns the crankshaft.

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internal-combustion engine (Britannica Elementary Encyclopedia)

Engines powered by internal combustion run cars, airplanes, lawn mowers, and other machines. Combustion means “burning.” Fuel, usually gasoline, burns inside an internal-combustion engine to make it work. Compared to earlier steam engines, internal-combustion engines are lighter and more powerful. ...

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