What is detonation in an engine?

Detonation in an engine refers to the phenomenon where the air-fuel mixture ignites prematurely, creating a rapid and uncontrolled release of energy. This occurs after the initial ignition spark has already ignited the fuel in the combustion chamber, leading to an additional ignition of the remaining fuel before it is supposed to ignite. The result is a sharp increase in pressure and temperature, which can be damaging to the engine.

This premature ignition can cause a knocking or pinging sound and ultimately lead to engine damage if left unaddressed. It is a serious issue that can resemble an explosion in the combustion chamber, in contrast to the smooth combustion that is intended. Understanding this concept is crucial for diagnosing engine problems and implementing correct adjustments, such as modifying the ignition timing or changing fuel types to prevent detonation.