Four-stroke Engine
Turn the crank and follow the piston through four strokes.
Intake · Piston moves down
Inlet: open · Outlet: closed
A simplified teaching model.
The red block is the piston, the bottom wheel is the crank, and the top center is the spark plug. The rod links reciprocation to rotation.
Crank turns: 0.00 · Completed cycles: 0
Four strokes take two crank turns. Only the power stroke supplies the driving push.
η = 1 − 1/ε0.4 ≈ 60%
Textbook Otto-cycle efficiency, assuming an ideal air model with heat-capacity ratio 1.4. This is not real engine efficiency.
How to play
Drag the crank, adjust the angle slider, or use Step and Auto. Change compression ratio to compare clearance and ideal efficiency.
Learn more
A gasoline engine uses a spark. A diesel engine compresses air until it is hot enough to ignite injected fuel. Valve timing and combustion are simplified here.
Reference used in the research notes