Several Key Technologies and Advices of Restricting Our Country’s Automatic Transmission Development

At present, several difficult issues restrict the development of self-owned brand automatic transmission, we hope these issues can arouse the attention from the related government department、the industrial organizations and the scientific research institutions.

1.     The mastering and controlling of dynamic behavior during the wet clutch engaging

The clutch is still the necessary unit during the overall speed change, controlling the clutch is always the key technology of automatic transmission development and design. The wet clutch used in the hydraulic automatic transmission is the main friction assembly, in the working condition of shift and shutting, the wet clutch friction pads need accuracy control, the core content of the key technology is to control the dynamic joint features of the wet clutch’s active and passive friction pads. There are the wet and dry clutches on the double clutch automatic transmission, controlling the double clutch automatic transmission mainly aims to control the overlapping degree and vehicle starting of the two clutches, the core content of the key technology is to control the dynamic joint features of the wet clutch’s active and passive friction pads. Aiming to the continuously variable automatic transmission without torque converter, we should add the wet clutch used for start, controlling the wet clutch is the key technology of continuously variable automatic transmission.

The clutch produces a mass of heat during the automatic transmission shift, if the heat dissipation is not timely, the clutch friction pads will generate part high temperature to lead the friction pads’ buckling deformation even firing gather. The material、abrasive resistance、friction factor and the friction face’s groove design are the key technology problems that must be urgently solved. Besides, the vehicle shift quality can directly influence the vehicle comfortableness and the system strength, easily arouses the powerful transient longitudinal impact of the transmission system, the main involved component is the wet clutch during the shift. It is the key component to improve the NVH performance of the vehicle.

Controlling the dynamic joint features of the wet clutch is the premise of the wet clutch accuracy control. The research about the dynamic joint features of the wet clutch is the key technology of automatic transmission research.

The wet clutch is the typical nonlinear system, the difficult point that builds its mathematical model of joint process is to refer to hydraulic-viscous transmission, and also to refer to the heat conduction pellet and other issues. Its expressed transmission torque and dynamic ability is the result of many complex factors. At present, the satisfying mathematical model doesn’t exit at abroad, this is a hot spot report, the domestic research about the dynamic joint process of the wet clutch is far from enough.

The dynamic joint process of the wet clutch refers to the nonlinear system、mechanics of viscous fluids、computing science、tribology and other subject fields, but compared with the abroad condition, the input for the wet clutch is little and lack of attention. We need continuously put into the financial resource to encourage more scientific research professional from different subject fields to be engaged in the research about the dynamic joint features of the wet clutch

2.     The control system and executive element of AMT

3.     The control of metal band transmission basic principle in CVT

4.     The metal band manufacturing in CVT is the key technology

5.     The design of CVT electrohydraulic control system is the difficult point

6.     Hydraulic pressure valve assembly and electronic control unit are the key factors of DCT development

7.     Summary

As the key technology of automatic transmission, the huge manufacturing enterprises all focus on the protection to the intellectual property in the world, for example of CVT electrohydraulic control system, although different electrohydraulic control system is almost accordant in the function, is totally different in the realization means, even it’s similar in the realization means, the obvious gaps will exit in the structure design. The key technologies that restrict the industrialization of our country’s automatic transmission still have the innovation potential seen from the technology evolution history, we should put into more finance、labor power and material resource, enhance the unity of production、study and research, strengthen the cooperation of the synchro development of the automatic transmission from the related enterprises, form the research stage of automatic transmission communal technology, focus on the self-dependent innovation, form the self-dependent developing ability aiming to our country’s national conditions, we can’t blindly joint the foreign-owned enterprises or imitate and transform the foreign products. We should try our best to make our country transform from the manufacturing huge country to the manufacturing strong country