Power Stroke
What is power stroke?
The power stroke is the part of the four-stroke engine cycle where the burning fuel-air mixture rapidly expands and forces the piston downward, producing the engine's usable power. This happens just after the piston passes top dead center at the end of the compression stroke, and the force pushing the piston down can exceed 15 tons with gas temperatures around 3,000–4,000 °F. Think of it as the only "working" stroke in the cycle—the other three strokes set it up and clean up after it.
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