Control oriented model of a variable geometry turbocharger in an engine with two EGR loops

In order to make modern Diesel engines cleaner and more fuel efficient, their air systems architecture become more and more complex. The control strategies of these systems must take account of the multiple components interactions with minimal calibration effort required. In this context, model based techniques are very attractive. In this paper we propose a control oriented model of a variable geometry turbocharger in an architecture with two exhaust gas recirculation (EGR) loops: high pressure (HP) and low pressure (LP). This model is implemented in a basic control strategy and evaluated experimentally during tests with LP or HP EGR. The results show that the choice of EGR circuit has a high influence on the turbocharger actuator position, but that this effect is well taken into account in the model proposed.