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.