A Study of the Dynamics of a Split-Torque, Geared-Neutral Transmission Mechanism

Abstract

A Split-Torque, Geared-Neutral mechanism offers considerable potential as a continuously variable transmission. However, dynamics, control, and driveability issues associated with power recirculation, performance during launch, and mode shift, can only be resolved with the help of a predictive mathematical model. A model, which allows for all anticipated changes in the kinematic structure, has been developed. A separate analysis is performed for each kinematic structure, with the frictional losses being characterized by external torques. The transmission is considered to be a part of a complete powertrain so that the simulation results can be evaluated in terms of vehicle performance criteria. Simulation results indicate correct qualitative behavior, and are included to illustrate the use of the model. Furthermore, these results provide insight into functional relationships existing between input commands and system performance, a prerequisite to developing control laws.