1. Intake Valve Opens: As the piston moves upward, the intake valve opens, allowing a fresh air-fuel mixture to enter the combustion chamber.
2. Compression: As the piston continues to move upward, the air-fuel mixture is compressed, increasing its pressure and temperature.
3. Exhaust Valve Closes: Just before the piston reaches the top of its stroke, the exhaust valve closes, sealing the combustion chamber. This prevents the air-fuel mixture from escaping.
4. Ignition: At the top of the compression stroke, the spark plug generates an electrical spark that ignites the air-fuel mixture, causing it to burn and expand rapidly.
5. Power Stroke: The rapid expansion of the burning gases pushes the piston downward with great force, generating power.
6. Exhaust Valve Opens: As the piston moves downward, the exhaust valve opens, allowing the burnt gases to escape from the combustion chamber.
7. Piston Reaches Bottom Dead Center: The piston continues to move downward until it reaches the bottom dead center (BDC), the lowest point in its travel.
8. Intake Valve Closes: Just before the piston reaches BDC, the intake valve closes, preventing any more air-fuel mixture from entering the combustion chamber.
The upward stroke of the two-stroke engine sets up the conditions for the next downward stroke, known as the power stroke, where the piston generates power. This sequence of events is repeated continuously to generate power for the engine.
