Research On Shift Hydraulic System Of Dual Clutch Transmission

In recent years,as the domestic automobile production and sales increase, rankingfirst in the world, the demand of transmission increases. Transmission is one of themost important components of the automobile,playing an important role on drivingperformance, fuel economy, driving comfort and other aspects.Dual clutchtransmission’s design concept,“Continuous power”, is warmly welcomed bycustomers, and the market share gradually increased.Many domestic large automobile enterprises and research institutions try todesign and research dual clutch transmission with better performance, and they havegot a lot of achievements.But, the domestic research mostly concentrates in theclutch engagement characteristic, the key technology of control system andthe mechanical structure, the research on the hydraulic system is less.The hydraulic system is one of the core technology of dual clutchtransmission,having a direct impact on the overall performance of the dual clutchtransmission. Based on this, the shift hydraulic system of dual clutch transmission isstudied in this paper, combined with the school-enterprise cooperation project "dualclutch transmission hydraulic key technology research".Shift hydraulic systemcontrols the shift fork movement in the process of the shift, make the shiftsynchronizer and gear engaged or separated, and control the shift force. While thework demand is satisfied, the shift force can not be too large, so as to ensure theservice life of the synchronizer. So,the control precision of hydraulic system directlyaffects the shift quality.Therefore,research on the shift hydraulic system and theinfluencing factors is of great significance.This paper starts from a detailed analysis of the working principle of the mainelements of the shift hydraulic system, and then the mathematical model is established,using AMESim simulation software HCD (Hydraulic Component Design) library, the VBSL valve, shifting force control valve, multiple way valve are established, and thewhole shift hydraulic system is finally established. According to the actual workingcondition, the simulation analysis of single valve and the whole system is combinedwith the theory and the experiment. The simulation analysis of shift hydraulic systemincludes the performance of different temperature, different load and different inputsignals. By using the mass simulation method, the key parameters affecting thedynamic characteristics of the system, such as the damping hole, spring stiffness, theinitial amount of compression spring, are analyzed, and the optimal range of each keyparameters are given. Finally, an optimization scheme is proposed, simulation resultsshow that the optimization scheme can improve the performance of the shift hydraulicsystem.The analysis methods and results in this paper can provide a reference forthe design and the improvement of the shift hydraulic system of dual clutchtransmission,and also provide a reference for making control strategy,havingimportant theoretical significance and practical value.