Acausal powertrain modelling with cycle-by-cycle spark ignition engine model

Due to more stringent emission limits and demand to improve fuel consumption, automotive researchers have been trying to develop detailed physics-based powertrain models for fuel consumption and emission control purposes. This paper presents an acausal powertrain model including vehicle longitudinal dynamics. The developed cycle-by-cycle spark ignition (SI) engine model is connected to a physics-based dynamic torque converter model, and the torque converter is connected to the rest of the powertrain (gear box, differential, tyres and chassis model) through acausal mechanical port connections. The SI engine speed and load are variable during the many-cycle powertrain simulation. The cycle-by-cycle four-stroke engine is based on a two-zone combustion modelling approach which assumes the engine speed is kept constant during a cycle. The SI engine and dynamic torque converter models are cross-validated with the GT-Power software and experimental data. The developed powertrain model in MapleSim is a suitable plant model that can be used for control applications due to the fast simulation time (faster than real time).