Mathematical Model for Elliptic Torus of Automotive Torque Converter and Fundamental Analysis of Its Effect on Performance

Passenger car torque converters have been designed with an increasingly flatter profile in recent years for the purpose of achieving a weight saving and more compact size. However, a flatter design tends to result in the reduced hydrodynamic performance. To improve its performance, a new flat torus of elliptic type method concentrating on the solution to flat TC was put forward, and four torque converters of different flatness ratios were designed to judge the superiority of the flat torus design method. The internal flow characteristics were numerically investigated using CFD codes and resulted in good agreement with experimental data. The results indicate that the main cause of this performance degradation can be attributed to deterioration of the velocity fields of the pump, and a case of flatness ratio 0.8 illustrates the reason that the performance designed by the flat torus design method based on the elliptic shape is more excellent than that of the traditional one. Furthermore, this study proposed a structure of removal of inner ring to improve the performance of torque converter.