Research On Clutch Hydraulic Control System Of Wet Dual Clutch Automatic Transmission

With the continuous improvement of people’s living, the demand for cars has increasedsteadily, and put forward higher requirements for Car’s dynamic performance, and comfort.With the help of automatic transmission, not only the drivability can be improved, the fueleconomy could enhanced as well, which would be a positive factor to reduce haze. Comparedwith developed countries, China’s automatic transmission market share is low, which has avery broad space for development.According to its structure, Automatic transmission can be divided into HydrodynamicMechanical Transmission, Automated Mechanical Transmission, Continuously VariableTransmission, and Double Clutch Transmission. DCT is evolved on the basis of a manualtransmission, production inheritance is good, and so the development of dual-clutchautomatic transmission is consistent with the status quo of China’s automotive industry.Wet DCT shifting process is mainly done by the hydraulic transmission controlmechanism. In addition to the associated control strategy, shifting performance is mainlydetermined by the hydraulic control system，so it is necessary to analysis the DCT clutchhydraulic control system.This dissertation is found by the school-enterprise cooperation project Theexploitation of hydraulic valve in Wet dual-clutch automatic transmission. The wet clutchDCT hydraulic control system is studied in this paper, the main contents are as follows:(1)This paper described the theory of wet DCT, and analysis the main circuit controlsubsystem, the lubrication control subsystem, and clutch control system in the clutchhydraulic control system. Then the mathematical models for the main hydraulic componentsin the clutch hydraulic control system is proposed, which would be the foundation of thesimulation.(2)Through the simulation software of AMESim, VBSH solenoid valve, the main regulating valve, lubricating oil control valve, VFS valve are build, and system simulationmodel based on their structure and working principle. The output pressure of main hydrauliccontrol valve and output flow of the lubricating valve, output pressure of VFS valve with thechange of current and the influence of oil viscosity on the sub system are analyzed, we findthat there are good matches between the dynamic simulation results and the experimentaldata. In the end, the simulation model of the entire hydraulic system is built.(3)Using the proposed simulation model, some key parameters that affect the dynamicperformance of the system is analyzed, like: the spring stiffness and pre tightening force,orifice, and then give a reasonable value to the parameters. The simulation results that usethe original and optimized parameters show that after optimization, the pressure fluctuationsreduced.In this paper, the DCT clutch hydraulic control system is analyzed in detail. Researchresults can be used as reference materials to design and optimize clutch hydraulic controlsystem, and can also provide a reference for the control strategy of DCT shifting processdesign.