Experimental Identification of Dynamic Characteristics of Hydrodynamic Torque Converters and Couplings

Hydrodynamic torque converters and couplings can be components of drive systems. The knowledge of their dynamic characteristics is necessary to calculate the dynamic response of the whole system under various time dependent excitations in order to guarantee safe working. The presented mathematical description of the nonlinear behavior consists of several linear models at several operating points. For a special linear “two port” description as used in electro-technique the four state variables are measured: the torques and the rotational speeds. The mathematical models are determined through an application of identification methods. Therefore a computer controlled testing bench has been constructed. High dynamic excitations have been realized with two hydrostatic drives which can be used as motors or brakes. The hydrodynamic component (torque converter or coupling) can be excited harmonically with the aid of the driving machines. By measuring the four state variables it is possible to get the frequency response functions. They are approximated by complex rational functions. The use of an inverse Fourier transformation into the time domain allows to calculate the dynamic behavior under general transient excitations.