New Control Strategies to Avoid Pre-Ignition in Higher CR Engines

Presently, lot of research is going on, to improve the thermal efficiency and there by the Fuel Economy of vehicles. Increasing the compression ratio to improve on the performance is an option. The compression ratio is a factor that influences the performance characteristics and FE of internal combustion engines. When targeting high output levels at low engine speeds, undesired combustion events called pre-ignition can occur. These pre-ignition events are typically accompanied by very high cylinder peak pressures which can lead to severe damage of engine component. The application engineer needs to optimize this undesired combustion event. This paper describes a systematic application developed to reduce pre-ignition. A case study was done to identify the pre-ignition phenomenon by using in-cylinder measurement. The paper also explains how air, fuel, injection angle and spark can help to avoid pre-ignition.