Hybrid Vehicle Power Transmission Modeling and Simulation with SimulationX

The holistic system of the hybrid power train must be investigated in order to optimize important functionalities such as boost, recovery brake energy, start-stop ability or pure electrical driving, downsizing of the combustion engine and E-machines. For this reason a multi-domain simulation model is necessary, by which the useful results for the design of hybrid electric vehicle can be offered to automobile manufacturer. As an important example, the first version of the Toyota Hybrid System of PRIUS is modelled by a multidomain software "ITI-SimulationX" in this paper. The concepts of hybrid synergy drive, especially an engine with dynamic characteristics, electric machine, planetary set and their control strategy are modelled. The modelling process shows that the unknown values of engine parameters in the model can be identified and validated. The complex interactions among the components are taken into account in a complete multidomain model. The simulation models provide an access to almost any physical quantity in the system. In the real powertrain only very few of them are accessible to measurements, so the insight into the system gets much deeper using simulation. Based on simulation models, the changes in the component design and hybrid control strategy can be easily evaluated, even in early design phases and without having to use a prototype. This allows an efficient pre-selection among different hybrid concepts and the optimal dimensioning of electrical machines and engine (e.g. rated power) of the hybrid power transmission.