Engine cylinder pressure estimation based on the robust sliding mode observer

Cylinder pressure is an important parameter for engine combustion analysis and fault diagnosis. In order to improve the estimation precision and the tracking speed of cylinder pressure, the method of engine cylinder pressure estimation based on the robust sliding mode observer is proposed. On the basis of the establishment of the engine dynamic model, it designes the robust sliding mode observer. According of the Lyapunov stability theory, it gets the feedback matrix of the robust sliding mode observer to guarantee the observer convergence, simultaneously, it proposes the robust control strategy to ensure the robustness for the nonlinear uncertain part of the observer. The simulated result show that, compared with the conventional sliding mode observer, the method of engine cylinder pressure estimation based on the robust sliding mode observer not only has higher estimation precision, but also has quicker tracking speed.