Analysis of combustion anomalies in supercharged DI gasoline engines; Analyse von Verbrennungsanomalien bei hoch aufgeladenen Ottomotoren mit Direkteinspritzung

The reduction of displacement in relation with air charging and direct injection is an effective method to reduce fuel consumption. Though sporadic, unwanted self ignition, so called pre ignition can occur when extremely rising the IMEP in the lower range of speed. This paper describes the facets of pre ignition using results of engine experiments and compares the characteristics with abnormal combustion of knocking and surface ignition. There is a classification of pre ignition into the entirety of abnormal combustion in spark ignition engines on this basis. Different release mechanisms of pre ignition on the possible potential of self ignition have been analysed using homogeneous reaction calculation.