Internal Combustion Engine
Interactive four-stroke cycle demonstration
1. Intake
2. Compression
3. Power
4. Exhaust
Spark plug
Intake
Exhaust
Crankshaft
Air + Fuel
Exhaust
TDC
Slow
Fast
1. Intake stroke
The intake valve opens and the piston moves down, creating a vacuum that draws in a mixture of air and fuel from the intake manifold.
Piston
Fuel-air mix
Spark / Fire
Exhaust gas
Key terms
TDC
— Top Dead Center
BDC
— Bottom Dead Center
Stroke
— Piston travel (TDC to BDC)
Cycle
— 4 strokes = 2 crank revolutions