In order to comply with future CO2 targets for passenger cars with gasoline engines, engines with reduced displacement in combination with direct injection and turbocharging were pushed in recent years. This engine downsizing allows a significant reduction in fuel consumption compared to a corresponding larger engine.

However, the increased boost pressure values and thus increased specific performance of these downsize engines exacerbate the problem of engine knocking and lead to new combustion anomalies at low rotation speed and full load conditions, the so-called Low Speed Preignition (LSPI). Here there is a sporadic spontaneous combustion of the fuel prior to the opening of the ignition spark. The occurrence of Low Speed Preignitions, accompanied by the loss of control of the combustion process and greatly increased peak pressures, currently represents the limiting factor for further efficiency gains in gasoline engines.