Design and Analysis of Torque Vectoring Systems for Vehicle Applications Using Function Power Graph Methodology

The purpose of this study is to understand the characteristics of torque vectoring systems for vehicle dynamic control applications, and to make design syntheses of new system configurations for future system development. As the requirement of vehicle safety and drivability arises, varied vehicle dynamic control technologies have been widely discussed and applied. In recent years, torque vectoring system draws more attention in automotive industry since the system is able to transfer more driving torque to certain wheel to make a traction distribution so that better vehicle safety and agility can be achieved. In order to make the research of torque vectoring systems more systematic and efficient, an integrated graph-based powertrain design and analysis methodology known as ""Function Power Graph"" (FPG) is proposed in this dissertation. The FPG is a symbolic graph which can present the configuration of a powertrain concisely and precisely. With the analysis and design techniques developed based on the FPG, the development process of torque vectoring systems can be performed. In this dissertation, the system configuration, degree of freedom, system function and the dynamic equation of the torque vectoring systems are investigated with the FPG analysis techniques. New possible system configurations are found with the FPG design techniques. Then, the limited-slip function and torque vectoring effect of the dual continuously variable transmission (DCVT) are evaluated with dynamic analysis. And the driving property of different DCVT systems are compared and discussed. At last, a practical experiment is performed and the correspondence to the simulation results is preliminarily approved. The main accomplishment of this research has two major parts: 1) The development of the FPG methodology which has been successfully applied to the design and analysis of hybrid systems, vehicle drivelines, automatic transmissions, and torque vectoring systems; 2) The investigation of the DCVT systems to understand the torque vectoring characteristics of the systems.