Hybrid and electric vehicles are complex and there is no master rule to find the best design. Here numerical simulation can help for the early decisions at the power train configuration. Within this context the system level modeling of vehicle power train is the object of study and in this work is shown how design evaluations can be easily simulated. The numerical models are implemented based on the open source and verified FAT-AK30 library using IEEE standard language, VHDL-AMS. The know-how added is at the interpretation of the library and application into the ANSYS-Simplorer environment oriented to a parallel hybrid electric vehicle demonstration case.