Here's how the compression ratio works:
1. As the piston moves down during the intake stroke, a mixture of air and fuel (or air only in the case of direct injection engines) is drawn into the combustion chamber.
2. When the piston reaches the bottom of its stroke, the intake valve closes, trapping the air-fuel mixture within the cylinder.
3. As the piston starts moving back up during the compression stroke, the air-fuel mixture is compressed, significantly reducing its volume.
4. The higher the compression ratio, the more the air-fuel mixture is compressed, resulting in a higher pressure inside the cylinder.
5. This higher pressure helps in achieving better combustion and generates more power when the compressed air-fuel mixture is ignited by the spark plug (in gasoline engines) or by the heat generated from the high compression itself (in diesel engines).
6. A higher compression ratio can lead to increased efficiency and power output of an engine, as more of the fuel's energy is converted into mechanical work during combustion. However, it also increases the engine's tendency to knock (premature ignition of the air-fuel mixture), which can damage engine components.
Therefore, engine designers carefully consider the compression ratio based on factors such as the fuel type, engine design, and desired performance characteristics to achieve a balance between power, efficiency, and reliability.
