Performance Analysis of Automotive Torque Converter Elements

Abstract

The hydrodynamic performance of a three-element automotive torque converter is analyzed by measuring flow between the elements with five-hole Pitot tubes. The performance of each element, including head, head loss, and efficiency, is defined and evaluated. The results show that the pump is the major source of loss in the speed ratio range where vehicles are most frequently operated in everyday driving. The loss coefficients for the three elements are also evaluated using a one-dimensional flow model. The friction loss coefficient of the turbine shows small variation over the entire tested speed ratio range, whereas the coefficients of the pump and stator vary considerably according to the operating speed ratio. The cause of loss in the pump and stator is investigated by flow visualization and three-dimensional numerical flow analysis. A low kinetic energy region in the pump and leading edge separation in the stator are clearly visualized or computed.