Unknown input estimation based sliding mode control for EGR-VGT diesel engine air-path

In this paper, we propose an unknown input estimation based sliding mode control (UIESMC) approach for air path in the EGR-VGT diesel engine. This proposed UIESMC controller is adopted to track the intake and exhaust manifold pressures, and compressor mass flow rate when under unknown inputs, which include the un-modeled dynamics, modeled parametric uncertainties and the unknown faults. These unknown inputs are estimated by PI observer by applying high gain at the integral term to satisfy the requirements of both estimation accuracy and less sensitivity to measure noises. This paper finally inverted the EGR and VGT gas mass flow rates into their corresponding valves positions by flow-position transformation module. Finally, through co-simulation results from AMESim and MATLAB/Simulink, the effectiveness and robustness of the proposed control strategy is demonstrated.