| The vehicle's automatic transmission technology is one of important research directions of the vehicle to improve and perfect the transmission. Electronically controlled automatic mechanical transmission (AMT) is not only a hydraulic automatic transmission can be handled easily strengths, but also retains many advantages of the original manual transmission, for example, high efficiency, low cost, simple structure, and good production of inheritance. It has been become the main direction of transmission development.In the design and development of AMT, the shift actuator design and optimization has been one of the important and difficult, and its performance directly affects the AMT system performance. Currently, there are shift actuator shift action is not accurate, institutions is poor reliability, not mass loading and other issues. Taking a car loaded with manual transmission for the study, the article design a electronic-hydraulic shift for the AMT system, including the following aspects of the analysis and research.①Automatic Transmission Control System summarized and the development history and present status of AMT system's basic components and working principle, and the AMT's key technical problems and control system structure are described.②Firstly, it introduces the basic process of AMT shift and the work principle of synchronizer, and analyzes the mechanical characteristics of the shift process. Secondly, according to the test performance parameters which are from measurement of the prototype engine, develops a two parameters of the best power and fuel economy shift schedule. Lastly, based on the standards for three driving cycles(Europe ECE+EUDC, Japan 10-15, American FTP75), establishes the vehicle simulation model. At the end, the simulation can calculate the maximum synchronous force, and estimate the maximum shift resistance.③On the basis of the maximum resistance of the hydraulic cylinder, analyzes the maximum load value of hydraulic cylinder. Then calculates the structural parameters of the hydraulic cylinder and selects the specifications of the other related hydraulic components.④Analysis of the fork-axis hydraulic drive circuit, establish mathematical model of the hydraulic system. Then selects the PID control as control method of the model which is widely used currently, and build a digital simulation model of the hydraulic system in Matlab / simulink environment.⑤It can obtain the dynamic response curve of the shift actuator through the simulation of the shift process, and analyze the different variable parameters on the system dynamic characteristics. The analysis of the simulation results verify the correctness of mathematical model and control strategy, and then verify the feasibility of design method. |
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