Online calculation of diesel engine torque dynamics

In current vehicles the actual value of engine torque is provided as interface signal to powertrain control units. For transient operation the dynamic behaviour of the combustion engine has to be estimated e.g. in the transmission control unit in order to coordinate the powertrain components. Due to the lack of provided data on the dynamic behaviour it needs to be modelled separately in each control unit, mainly map-based with high calibration effort. The engine control unit (ECU) has access to the relevant sensor and reference values for online calculation of diesel engine dynamics. Within this publication a model-based online torque calculation is proposed taking into account information that is already available in standard ECUs. Additionally the current torque reserve is computed. The calculation of characteristic parameters defining the dynamic behaviour for torque requests is outlined. Based on these signals prediction of engine dynamics is simplified and can significantly reduce the calibration effort e.g. in transmission control unit. The presented paper describes the calculation method and compares simulation results to engine test bed measurements for validation.