Study On The Evaluation Method Of Shift Quality For The DCT

Recently,due to the excellent shift quality and high transmission efficiency,dual clutch automatic transmission has gained more and more attention in the field of automotive transmission technology.However,most research on the shift control of DCT focus mainly on the DCT start control and shift schedule development,few research about the quality of gearshift for double clutch automatic transmission has been seen yet.This paper presents an shift quality analysis method,providing a guidance for the DCT production.Shift quality has a direct influence on the satisfaction of driver,however the traditional shift quality research is not mature enough considering only jerk,shift time and friction work.Latest work have also considered vehicle power performance,economy,durability and comfort,but the dynamic of the system is not included.This paper establish engine model,clutch model and vehicle impedance model according to the basic structure and working principle of DCT.Then,the dynamic model of the whole vehicle is established,and the dynamic analysis is carried out respectively on the starting and shifting process.In addition,the structural characteristics and the shift process of a seven speed dry dual clutch automatic transmission is analyzed respectively to develop economic and dynamic shift strategy.Simulation is executed adopting Matlab/Simulink to testify shift performance of the shift schedule.Based on the analysis of the factors affecting the shift quality of the double clutch automatic transmission,the shift quality evaluation index system is constructed,and the method of improving the shift quality is developed.Based on the fuzzy gray clustering method and entropy weight method,this paper establishes a evaluation system of shift quality.First,the quality evaluation index of the shift is classified and combined with the weight of grey clustering method and entropy method,the relationship between the evaluation index and the vehicle performances will be figure out.Then,the shift quality evaluation system is established based on the driving force,transmission durability and comfort.