Recently, a new power split hybrid electric vehicle drive train has been developed by the Corporate Research and Development Department of the Robert Bosch Company. The new drive train differs from a conventional one in many respects. In this paper we investigate how these differences affect the vibrational behavior of the drive line. With the aid of a linear mechanical model, a modal analysis is performed and the effect of the control of the drive train on the eigenvibrations is studied. The analysis reveals, for example, a shuffle behavior, which can also be observed in vehicles with conventional drive train. The constant of the I part of the controller influences the vibrational behavior in quite a complex way. Starting from zero and steadily increasing the control parameter, one of the modes undergoes three metamorphoses. On the basis of this fundamental understanding, two strategies for the optimization of the drive line vibrational behavior are proposed. Furthermore, the simple mechanical model is refined with regard to various aspects. For example, tire slip is taken into account and a two-track model capturing asymmetric vibrations of the two axle shafts or wheels is considered.
Comparative Study of Different Drive-train Driving Performances for the Input Split Type Hybrid Electric Vehicle