Acoustic source identification and knock detection in a Wankel engine operating on gasoline and hydrogen fuels

This study presents an experimental investigation into the acoustic emissions of a Wankel rotary engine fueled by three distinct injection strategies: unleaded gasoline (E10), hydrogen with water addition (H2W), and pure hydrogen (H2). Measurements were carried out on an engine test bench under steady-state operating conditions. The analysis encompassed both sound pressure levels and frequency-domain characteristics of the acoustic signals. A microphone array in conjunction with CAE Noise Inspector software was used to capture and analyse noise emissions originating from the combustion chamber. The results revealed distinct variations in acoustic behaviour depending on the fuel type. Notably, the engine powered by pure hydrogen exhibited the highest amplitude of emitted combustion noise, potentially attributable to knocking combustion phenomena. The study underscores that fuel selection has a significant impact on the acoustic signature of the Wankel engine. Furthermore, the adopted measurement methodology proved effective in identifying combustion-related sound patterns and provides a foundation for future optimisation of rotary engines operating on alternative fuels.