Modelling of the exhaust gas recirculation rate based on the in-cylinder pressure measurement for a passenger car diesel engine

Abstract

This paper proposes a modelling of the exhaust gas recirculation rate using the in-cylinder pressure sensor for a passenger car diesel engine. Traditional modelling approaches for the exhaust gas recirculation rate normally use variables which are measured for a long intake-exhaust air path so that a time delay is inevitable. In addition, the model structure is complex, since many non-linear or unmeasurable variables such as the volumetric efficiency and the efficiency of the exhaust gas recirculation cooler have to be considered in the model. The proposed exhaust gas recirculation rate model is based on the in-cylinder pressure measurement which provides instantaneous information about combustion. Therefore, when this information is used, it is able to model the exhaust gas recirculation rate with a fast response compared with traditional modelling approaches. Furthermore, the proposed model can have a simple model structure since the model does not require consideration of the non-linear or unmeasurable parameters of the air path. The proposed exhaust gas recirculation rate model was integrated into an engine control unit and validated through engine experiments on various operating conditions.