IC Engine: Tracking Control for an Inlet Manifold with EGR

Engine controls are usually based on a hierarchical approach because of the complex phenomena occurring in a spark ignition engine. The inlet air control is one of the most important part, that constrains performances in terms of torque and speed dynamics and also emissions. This paper deals with inlet air modeling and control of a spark ignition engine with Exhaust Gas Recirculation (EGR). In the first part, a non linear model of the manifold pressure, based on the common St Venant equation is presented. In this model, represented by a differential equation, the variation of manifold pressure is due to inlet and exhaust manifold flows. In a second part, a manifold pressure control law, which takes into account the throttle actuator and an EGR valve dynamics is presented. It allows to follow a manifold pressure trajectory with a desired parameter air-EGR ratio. This parameter is used to reduce mainly the NOx particles, by decreasing combustion's temperature. Moreover, an analysis has been carried out to take into account the noise appearing on the outputs of the system. Finally, the results obtained in simulation with then environment Matlab/Simulink, using the developed control law, are exposed on several cases.