Observer Based Robust Control Design for Mitigation of Cyclic Torque Imbalance in Gasoline Engines

Cyclic torque imbalance is one of the major problems of gasoline engines that is caused due to variations between combustion cycles. Output torque generated by the engine cylinder is required to be same for each combustion cycle but variations occur in it due to disturbances in torque generation. Although, cyclic torque imbalance was sporadically studied but it was not considered a concern until measurement of consecutive engine cycles was made possible.In this paper, an Observer Based Robust Control (OBRC) methodology is proposed to develop a novel model based unified framework for detection and mitigation of cyc1ic torque imbalance. Based on estimated net piston force (fn), second order sliding mode control technique is applied to mitigate imbalance in the cyclic torque; which is generated by inducing fault in the fuel injection subsystem. The unified framework is developed by using First Principle-based Engine Model (FPEM). The proposed Observer Based Robust Control methodology is validated by MATLAB/Simulink simulations.