Simulation-Aided Development of Prechamber Ignition System for a Lean-Burn Gasoline Direct Injection Motor-Sport Engine

Abstract

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, motor-sport 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. Prechamber 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 gasoline direct injection (GDI) engine and a passive prechamber is developed with the aid of a computational fluid dynamics (CFD) tool. The finalized prechamber design benefited in a significant reduction in burn duration, reduced cyclic variation, knock limit extension, and higher performance.