Nonlinear observer-based torque control for SI engine

In this paper, a nonlinear torque observer for spark ignition (SI) engine is proposed and a torque control method based on the observer is presented. In the observer, a torque production model is employed to give the nominal value of torque estimation. Then, using the rotational dynamic equation of the crankshaft, a nonlinear adjusting law is added to correct the nominal estimation. The proposed observer is used to realize closed loop torque control, where the torque demand is given by solving an optimal speed tracking problem. To demonstrate the observer and torque controller, experimental results are shown finally.