Low pressure EGR control for a turbocharged diesel HCCI engine

In order to improve diesel engine performances, new technologies has been investigated. A major development in this context, concerns the airpath architecture for which several setups are envisaged, variable geometry turbines, double stage turbochargers, high and low pressure EGR circuits. In parallel, the control structures have to be improved in order to address the new challenges. Adaptation of the conventional strategies based on steady state maps and proportional integral controllers becomes very difficult. This paper proposes a new method for low pressure EGR control. The proposed strategy is based on a physical representation of the system and can be easily adapted to new architectures. It has been validated by simulation and experimentally on a four cylinder diesel engine.