Toyota has developed a new system, which uses integrated control of powertrain by PowerTrain Management (PTM), in order to improve driving comfort and reliability. This system is currently in use on Lexus's new LS460.
This system is composed of 4 parts: a generation part, a mediating part, a modification part and a distribution part. In each part, processes are based on drive power and torque. In the generation part, requests from a programmed model driver, Driving Support Computer and Vehicle Dynamics Integrated Management (VDIM) are generated and expressed by drive power. In the mediating part, most suitable vehicle drive power was selected among the requests. In the modification part, the selected request is modified using a programmed powertrain model, which considers internal combustion engine condition and powertrain response and transmission's tolerance. In the distribution part, optimized engine torque and gear ratio are processed.
With this system, the most suitable vehicle drive power is accurately accomplished with optimized engine torque and gear ratio. Drive system vibration is reduced. While response, and continuity of drive power before and after changing gears are improved. Consequently driving comfort is constantly improved in various driving situations.
In addition a highly reliable and efficient design is accomplished by its hierarchy structure and independence of actuator control.
This paper describes the structure, features and performance of this system in detail.