Study On The Characteristics Of Power Flow During Shifting Process In DSG

In the study,the object is the direct shift gearbox(DSG).The charactenistics of charging oil are studied.The trending of power flow is analyzed.Shifting control strategy is set with PID control and fuzzy control.Experiments of shifting control with engine and double clutches are performed.Firstly,the mathematic model of wet clutch charging oil system controlled by proportional valve is built and simulated,and the influence of the oil tempreture and the input rotating speed on charging charactenistics is analyzed.Double clutch shift model was established,based on the analysis of the power flow,the generation mechanism of cycle power was analyzed,the optimal shift time was deduced.PID control and fuzzy-PID control were used to control the shift process,shift quality has been optimized after controlling.Combining multiple level analysis and fuzzy control methods,the evaluation system of DSG shift quality based on different shift quality evaluation was established.The weighting of different indicators under different shift demand were calculated,it laid the foundation for establishing the shift model.Moreover,a seven-degree-of-freedom dynamic model for DSG shift process with double clutches engaged is built.The shift control strategy is set up using fuzzy control theory and PI control for different kinds of loads including the resistance from the ground and the air.The advantages of the shift joint control were obtained through the simulation.Experiment is done to test the shift charactenistics with different hydraulic overlap time on the same loads.A conclusion that shift joint control with suitable hydraulic overlap can suppress the cycle power and optimize the shift quality.