1. Intake Stroke:
- The piston moves downward within the cylinder.
- The intake valve opens, allowing a mixture of air and gasoline from the carburetor or fuel injection system to enter the cylinder.
2. Compression Stroke:
- The piston moves upward, compressing the air-fuel mixture within the cylinder.
- This increases its temperature and pressure, creating an ideal environment for combustion.
3. Power Stroke:
- At the top of the compression stroke, a spark plug ignites the compressed air-fuel mixture.
- The ignited mixture rapidly burns and expands, creating high-pressure gases within the cylinder.
- The expanding gases push the piston downward, generating power.
4. Exhaust Stroke:
- The exhaust valve opens, and the piston moves upward, pushing the burned gases out of the cylinder and through the exhaust system.
- The burnt gases are released into the atmosphere, and the cylinder is ready for the next cycle.
This sequence of events—intake, compression, power, and exhaust—repeats continuously as long as the engine is running. The power generated during the power stroke is transmitted to the drivetrain, which turns the wheels and propels the vehicle forward.
The speed of the engine is controlled by varying the amount of air-fuel mixture entering the cylinder during the intake stroke. More air-fuel mixture leads to more power and higher engine speeds, while less air-fuel mixture results in lower power and slower engine speeds.
Modern gasoline engines often incorporate additional technologies to optimize performance, efficiency, and emissions control, such as fuel injection, electronic engine management systems, and catalytic converters.
