Study On And Design Of The TCU Of Vehicle Automatic Transmission

Automatic transmission plays an important role in raising the level of vehicle performance and quality, and forms one of the bottlenecks of the progress of domestic automobile industry. This thesis takes the TCU of AT as the focus and the work is done around the project"Fundamental Key Techniques of Automatic Transmission's TCU"supported by Anhui Bureau of Science & Technology.With an understanding of the global and domestic status, the composition and principles of automatic transmission, the thesis proposes an approach of the design of TCU based on the AT mechanism and several specific chips.Based on an analysis of the structure of hydraulic torque converter, some roles concerning the operation of the torque converter is acquired. The thesis proposes a two-parameter shift schedule based on throttle openness and vehicle speed, and transfers the acquired shift schedule into the microcontroller's software module. The control of the main line oil pressure during gear shift is also studied. According to the requirements of the AT's performance, the hardware of TCU was configured and implemented by modularized design. The software was programmed with the aid of CodeWarrior development tools. Hardware and software measures against interference were adopted in the design.The prototype TCU was tested in laboratory. In the test of the of solenoid valve drive circuit, two shift valves fulfilled the shift among 4 states and met the requirement of logic control of shift valves. The close-loop current control of the proportional valve achieved quick response and high accuracy. The results verified that the design can accurately control the valves'states and position with the acquired information on vehicle status.