Research On Adaptive Method Of Prefilling For Wet Dual Clutch

When the wet dual clutch automatic transmission(WDCT)begins to work,the first thing to do is prefilling.The proper prefilling pressure is more conducive to clutch engagement.If the prefilling pressure is too high,the touch point pressure when the clutch is engaged will be higher than the touch point pressure during smooth engagement,which will cause brutal contact of the clutch and cause the jerk of the system;on the contrary,if the prefilling pressure is too low,the sliding time during clutch engagement will be prolonged,increase clutch wear and shorten its service life.In the development of WDCT,to solve under-fill and over-fill of the vehicle during the starting and shifting the primary method is the compensation of the clutch's filling pressure.Based on this,the corresponding research is carried out.In this paper,firstly,a vehicle dynamic model equipped with WDCT is established,which includes clutch hydraulic actuator.The model can simulate the effect of prefilling pressure on vehicle starting and shifting process,which provides an algorithm verification platform for the research of prefilling adaptive method.Then,according to the performance of under-fill and over-fill in the model,the control algorithms based on iterative learning and fuzzy control are proposed.Taking the speed difference between the clutch driving disc and the driven disk as the main monitoring factor,the prefilling pressure of the wet clutch at the next moment is compensated by judging the speed difference between the driving disc and driven disc,so as to achieve the purpose of prefilling adaptation.Finally,combing the established vehicle model,with the proposed control algorithm,the simulation,and the rapid prototype simulation by dSPACE are carried.The results show that the proposed control algorithm in the simulation model and the rapid control prototype are basically consistent,which can improve the jerk and friction work of the vehicle in the process of starting and shifting causing by over-fill and under-fill,and fourth improve the shift quality of the vehicle to a certain extent.