Torque Converters

This chapter provides readers a systematic description on the structure, operation principles, and input-output characteristics of torque converters. It starts with the basic structure and geometry of torque converters with lock-up capability and a qualitative analysis on the functionality. The chapter focuses on the mechanism of fluid circulation and torque multiplication, including fluid velocity diagrams, analysis of the angular momentum of automatic transmission fluid (ATF) circulating inside the torque converter, and torque formulations on the torque converter elements. In a torque converter, power is transmitted from the impeller to the turbine by ATF circulation inside the torque converter. The design path is a circle on the torus section that is assumed to be the mean flow path of ATF circulating as a continuum in the three elements of the torque converter. The chapter presents the torque capacity formulation and input-output characteristics of torque converters.