Engine Knock
Abnormal combustion, often producing audible sound, caused by autoignition of the air/fuel mixture.
Knock produces extreme local temperatures in the cylinder. These high heat quantities place a severe strain on the piston, valves and cylinder head, and can lead to damage.
See also: Auto-Ignition Temperature, Internal Combustion Engine, Octane Number, Pre Ignition.
Subjects: Engines Noise & Vibration