Simulation aided development of pre-chamber ignition system for a lean-burn gasoline direct injection motor-sport engine

Due to recent regulation changes to restricted fuel usage in various motor-sport events, motor-sport engine manufacturers have started to focus on improving the thermal efficiency and often claim thermal efficiency figures well above equivalent road car engines. With limited fuel allowance, motorsport engines are operated with a lean air-fuel mixture to benefit from higher cycle efficiency, requiring an ignition system that is suitable for the lean mixture. Pre-chamber ignition is identified as a promising method to improve lean limit and has the potential to reduce end gas auto-ignition. This paper analyses the full-load performance of a motor-sport lean-burn GDI engine and a passive pre-chamber is developed with the aid of a CFD tool. The finalized pre-chamber design benefited in a significant reduction in burn duration, reduced cyclic variation, knock limit extension and higher performance.