Development of a sensorless estimation algorithm of the injection timing and rate for an HSDI common-rail injector

The performance of a common-rail fuel injection system and its effects on diesel engine combustion are strongly influenced by the injector characteristics. The injection timing and the injection rate of the common-rail injection system are important factors for combustion control and pollutant formation mechanism during the engine operation. This paper presents a dynamic model of the common-rail injector for high speed direct injection (HSDI) diesel engines and introduces a methodology for estimating the injection timing and the injection rate of the injector. The numerical simulation and the experimental results show that the proposed sliding mode observer (SMO) can effectively estimate the injection timing and the injection rate of the common-rail injector.