Irregular combustion in supercharged spark ignition engines – pre-ignition and other phenomena

Abstract Downsizing is one of the most promising concepts to reduce fuel consumption of gasoline engines. However, it is currently limited by the occurrence of irregular combustion phenomena at high loads. This paper provides an overview of the combustion phenomena to be taken into account. At first, knock, extreme knock, surface ignition, and pre-ignition are briefly introduced by a description of their phenomenology. Since pre-ignition is the newest and least explored of these phenomena, the results of a study about its phenomenology and reasons for its occurrence are presented. Finally, auto-ignition in general is discussed, taking into account its occurrence, its effect, and its avoidance. Thereby, the general remarks about auto-ignition are related to the phenomena observable in real engines.