The present paper focuses on a system and an appropriate controller concept for an advanced air management system of a turbocharged passenger car diesel engine. The proposed air management system consists of a VTG turbocharger, two separate EGR loops, a non-cooled high-pressure EGR and a cooled low-pressure EGR loop. In the low pressure EGR loop, the exhaust gas leaving the particulate filter is mixed with fresh air just in front of the compressor inlet.
The first step consisted of developing a sensor and actuator concept. Prior to conducting engine tests on this system, GT power simulations were performed. Additionally, a MATLAB/Simulink model was created to design a model-based predictive controller. This model is mainly founded on physical equations, allowing for easy adaptation to various systems.
At the beginning of the engine test stage, stationary measurements were conducted to examine the influence of variations of the EGR rate, boost pressure, fresh air mass, etc. These tests were carried out in an open loop without an integrated controller for the air management system. The results were used to optimize the Simulink simulation model.
As to the controller concept, a model-based predictive approach is presented which uses a simplified simulation model of the complete air path for the prediction.
Furthermore, the system design on the dynamometer and the interaction of the individual steps are described. Simulation results of the new controller type and first results of the controller on the dynamometer are presented, as well.
Due to modifications of the state-of-the-art high-pressure system arising from the integration of a low-pressure EGR line, additional measures need to be taken to protect the components in the inlet air path from harmful impact resulting from corrosion and particulates.