AMT's Shift Strategy And Software System Design

Compared with Hydraulic Automatic Transmission and Continuously Variable Transmission, Automatic Mechanical Transmission (AMT) has advantages of higher efficiency, easier installation and lower cost in manufacturing, so there is a vast potential market for AMT in this field. It is said that AMT will be the emphasis of automated transmission development in China. This paper mainly concerns Gear position decision, AMT software system and online fault detection.Compared with Hydraulic Automatic Transmission and Continuously Variable Transmission, Automatic Mechanical Transmission (AMT) has advantages of higher efficiency, easier installation and lower cost in manufacturing, so there is a vast potential market for AMT in this field. It is said that AMT will be the emphasis of automated transmission development in China. This paper mainly concerns Gear position decision, AMT software system and online fault detection.At the beginning of the thesis, the structure and working theory of the automatic mechanical transmission are comprehensively discussed. And then the shifting strategy, which is one of key technologies in AMT, was analyzed. The shifting strategy refers to the principles that vary from different shifts, and it is the key technology of AMT development. It is directly related to the car's dynamic performance, economical and comfort. Driver-Vehicle-Environment relation was analyzed in the paper, and so were the different ways of improving two-parameter shifting strategy under different environment.The main content of auto shift system is the electrical controlled software. Freescale's MC9S12C32 was used as MCU. C programming language was used to design the electrical controlled software, the interrupt control is the main method, which has dramatically decreased the difficulty of programming. And in the meantime it improves the software's readability, maintainability, replant and ensures the software's extendable, recompose.The software system's structure schematics and partial codes of the program were introduced in this part, and the components of electrical control software were given and studied in detail, including the flow charts.On the basis of discussing construction and working principle of the AMT electronical control system, the article presents correct diagnostic method of the AMT electronical control system carried out by means of logic relation among signals of the system. Fault can be categorized into following categories based on the places it happens: Engine related faults which includes rotational speed sensor and throttle; Gear box related faults which includes shift sensors, rotational speed sensor and shifting actuator fault ;Clutch related faults which includes clutch's range of sensor, actuator and transmission itself fault.Shuailin light weight truck of JAC was used as research target. The shifting principles test, shifting quality control test and shifting principles test on vehicle's performance were carried out on the truck. And the experiment results were analyzed. The basic function of AMT system was realized, including start control, auto shift while driving. It has paved the way to the further study in the future.