Switched Causal Modeling of Transmission With Clutch in Hybrid Electric Vehicles

Certain difficulties arise when attempting to model a clutch in a power train transmission due to its nonlinear behavior. Two different states have to be taken into account-the first being when the clutch is locked and the second being when the clutch is slipping. In this paper, a clutch model is developed using the energetic macroscopic representation, which is, in turn, used in the modeling of complete hybrid electric vehicles (HEVs). Two different models are used, and a specific condition defining the commutation between both models with respect to the physical energy flow is proposed. A Petri net is employed to activate one of the models, depending on the clutch state (locked or slipping). This model allows us to implement without difficulty a simulation of the clutch with a relatively short computation time.