Prediction of Driving Cycles by Means of a Co-Simulation Framework for the Evaluation of IC Engine Tailpipe Emissions

The reliable prediction of pollutant emissions generated by IC engine powertrains during the WLTP driving cycle is a key aspect to test and optimize different configurations, in order to respect the stringent emission limits. This work describes the application of an integrated modeling tool in a co-simulation environment, coupling a 1D fluid dynamic code for engine simulation with a specific numerical code for aftertreatment modelling by means of a robust numerical approach, to achieve a complete methodology for detailed simulations of driving cycles. The main goal is to allow an accurate 1D simulation of the unsteady flows along the intake and exhaust systems and to apply advanced thermodynamic combustion models for the calculation of cylinder-out emissions. The simulation of the after-treatment systems is then carried out by a steady state model including a detailed chemistry approach, which allows an accurate prediction of the conversion of pollutants under the wide range of operating conditions of a driving cycle. This co-simulation environment has been validated against the measured dataset of an SI, natural gas engine which was instrumented and tested at EMPA labs.