Engine cylinder pressure estimation using second-order sliding mode observer based on super-twisting algorithm

Using observer to estimate cylinder pressure is significant for control and engine on-line diagnosis. Aiming to overcome the chattering phenomenon of sliding mode observer, a second-order sliding mode observer is designed based on the engine cylinder pressure model. And then part of the continuous observer injectors are designed to overcome the chattering problem and eliminate the error based on super-twisting algorithm. In addition, the convergence of system error in finite time is guaranteed by designing fittable observer parameters using second-order sliding mode theory. The simulation results show that the chattering is eliminated by using the proposed approach and the estimated error is reduced by about 10% compared with the method in [8].