Engine speed limiter for watercrafts

Engine speed limiters are safety devices designed to prevent an engine from exceeding a predetermined high speed. The speed limiter herewith presented is designed for large and sudden load variations which require accurate and fast air-fuel ratio control. It is based on feedback linearization and online estimation of the load torque. Experimental testing was conducted with a Sea-Doo personal watercraft. A system was used to bypass the engine's electronic control unit (ECU) injector commands in order to use those of the new controller. Experimental results indicate that it reaches higher performances than the usual ECU injection cutoff strategy.