Application of nonlinear sliding-mode observers for cylinder pressure reconstruction

Abstract The theoretical development of combining nonlinear sliding observers with internal combustion engine cycle simulations in order to estimate individual cylinder pressures was first presented by Kao and Moskwa. This new nonlinear approach to the observation of engine cylinder pressure, combustion heat release, and torque estimation has been shown to have good performance, with fast convergence and stability. In this paper, the nonlinear sliding observer gains are modified to be a function of crank angle. The technique is applied to a six-cylinder engine. The experimental results show the possibilities of application of this nonlinear observer to individual cylinder pressure estimation.