What is Engine Knocking?

[McLincoln]

Engine knocking is a malfunction phenomenon caused by premature ignition. In diesel vehicles, fuel is injected into the cylinder before the piston reaches the top dead center, leading to combustion while the piston is still moving upward. This produces a distinct sound, which is the phenomenon of engine knocking. Additional information: 1. Knocking: (1) Knocking is the most significant form of abnormal combustion in an engine, often occurring at high compression ratios. (2) When it occurs, the engine produces a high-frequency metallic knocking sound, hence it is also called detonation. 2. Effects of knocking: (1) When knocking is mild, the engine's power may slightly increase. (2) In severe cases, power and speed decrease, operation becomes unstable, the engine shakes severely, and it may overheat and emit black smoke.