The engine knock analysis – An overview

Knocking combustion in spark-ignition (SI) engines is an abnormal combustion phenomenon which can constrain the engine performance and thermal efficiency. It can also result in severe permanent engine damage under certain operating conditions. This paper systematically reviews the engine knock phenomenon, including the mechanisms, influencing factors, consequences and detection methods etc. It introduces the visualization researches, simulations and some judging indexes of engine knock. Three mathematical models which can predict the engine knock, and various kinds of methods of suppressing knock are summarized. Finally, this paper puts forward some new suggestions on the weakness in the researches of knocking combustion.