A Combustion Cycle Model for Stationary and Transient Engine Operation

Abstract

Since novel approaches of diesel engine control have to balance the emissions and the generated torque most accurately during highly transient engine operation, exact cycle-by-cycle estimates of these engine outputs are mandatory. Accordingly, this paper develops a control-oriented combustion cycle model to determine the indicated mean effective pressure as well as the nitrogen oxide and the smoke emissions. The proposed model has a hybrid structure, i.e. the gas exchange and compression are modeled physics-based with lumped mass and energy balances, whereas the combustion is approximated by a data-based approach due to the complex chemical reaction kinetics. Thus, the model outputs are described with respect to the time-varying signals of the transient air path conditions (intake pressure, oxygen concentration, and temperature) as well as the inputs adjusted by the fuel injection (start position and mass of each fuel injection pulse). Measurement data is used for the parametrization and validation of the model.