Analysis of Crank Angle Resolved In-Cylinder Combustion Modeling for Real Time Diesel Engine Simulations

Mainly due to environmental regulation, future Engine Control Unit (ECU) will be equipped with in-cylinder pressure sensors. The introduction of this innovative solution has increased the number of involved variables, requiring an unceasing improvement in the modeling approaches and in the computational capabilities of Engine Control Unit (ECU). Hardware in the Loop (HIL) test system therefore has to provide in-cylinder pressure in real time from an adequate model. This paper describes a synthesis of our study targeted to the development of in-cylinder crank angle combustion model excluding look up tables, dedicated to HIL test bench. The main objective of the present paper is a comprehensive analysis of a reduced combustion model, applied to a direct injection Diesel engine at varying engine operating range, including single injection and multi injection strategies. The developed model has required an important identification step to calibrate the parameters of the combustion model based on single and double Wiebe function. The difficulty to derive one calibrated model for all engine operations is discussed. This study allows to develop two calibrated combustion models one applied to high engine speeds and the other to low and medium engine speeds. The global model is able to run within one crank angle degree required by real time simulations. The precision of the model is analyzed by comparing in-cylinder pressure traces and ignition delay times at varying engine operating conditions.