1. Intake Stroke: The piston moves downward, creating a vacuum in the cylinder. This vacuum draws in a mixture of air and fuel through the intake valve.
2. Compression Stroke: The piston moves upward, compressing the air-fuel mixture. The intake valve closes during this stroke, trapping the mixture in the cylinder.
3. Power Stroke: The compressed air-fuel mixture is ignited by a spark plug (in gasoline engines) or by heat and pressure (in diesel engines). The burning fuel expands rapidly, pushing the piston down and creating power.
4. Exhaust Stroke: The piston moves upward again, pushing the burned exhaust gases out of the cylinder through the exhaust valve. This valve opens during this stroke, allowing the spent gases to escape.
These four strokes repeat in a continuous cycle, converting the chemical energy of fuel into mechanical energy that powers the engine.
