Modeling and Time Discrete Characteristics Analysis of the Oil Filling Process of Wet Clutch for a Specialized Vehicle’s Automatic Transmission

The automatic transmission of a specialized vehicle encountered challenges in achieving stable oil filling time due to the considerable variability of related parameters and the non-linear trends in the variation of individual product parameters over time. To investigate the underlying causes of this phenomenon and enhance the oil filling efficiency, a detailed model of the clutch oil filling process during gear shifting was established in this paper, which included dynamic models of the key components such as the hydraulic system, clutch, proportional valve, and oil passages. Physical experiments were performed on the test bench to compare with the simulation results. The results showed that the correlation between the simulation model and the test bench was well, which verified the effectiveness of the simulation model. Based on analyzing the clutch filling process, the effects of parameters such as orifice diameter, piston cavity clearance, clutch gap, and oil injection pressure on the filling time response of the system were primarily considered, and dynamic simulations were carried out to investigate the influence of these parameters on the clutch filling time. These results provided substantial theoretical support for the optimization and calibration of relevant parameters in the subsequent design iterations of the specialized vehicle's automatic transmission.