Real-time cylinder pressure and indicated torque estimation via second order sliding modes

In this paper an online estimator design is proposed for indicated torque and individual cylinder combustion pressure estimation of an internal combustion (IC) engine. The information on cylinder pressure and indicated torque can be utilized in several engine control and diagnostics problems such as torque tracking, (transient) air-fuel-ratio regulation, ignition timing, lean burn engine control, idle speed control, cylinder misfire and abnormal combustion detections. The proposed strategy requires the crank angle and crankshaft speed measurements as well as fairly accurate combustion and crankshaft rotational dynamical models.