What is the primary objective of proper valve timing and overlap in an engine?

The primary objective of proper valve timing and overlap in an engine is to improve volumetric efficiency and lower operating temperature. Valve timing refers to the precise moments when the intake and exhaust valves open and close during the engine's cycle. When these events are synchronized correctly, it ensures that the intake air-fuel mixture enters the combustion chamber smoothly while allowing exhaust gases to exit effectively.

Improving volumetric efficiency means maximizing the amount of air-fuel mixture that fills the combustion chamber, which can lead to more power being produced for the same size engine. Proper overlap timing, which is the period when both the intake and exhaust valves are slightly open, allows for better scavenging of exhaust gases, reducing residual gases and improving the fresh charge entering the cylinder. This efficient filling and expulsion of gases not only contributes to better performance but also aids in maintaining lower operating temperatures. By optimizing how gases flow in and out of the engine, the engine can operate more efficiently, which contributes to better overall performance and efficiency.