Oil Pan Sloshing In Automatic Transmissions

摘要

A CFD methodology has been developed and applied to investigate the oil pan sloshing phenomenon and identify key design parameters to prevent oil pump starvation under various vehicle-maneuvering conditions. In conjunction with the CFD method development, the analysis has been qualitatively validated by vehicle testing. The analytical focus is on gradability and oil sloshing under six operating conditions such that the dynamic oil level and pick up location do not cause pump starvation. Both oil pickup and return rates together with different pick-up locations are included for overall evaluation throughout the course of the sloshing study. Vehicle driving conditions are characterized by "G-forces," with acceleration at 0.72g, deceleration 0.92g, right and left turn 0.85g, and 60% grade for up- and down-slope operations. The parameter interacting effects are assessed with temperatures ranging from 32℉ to 200 ℉, and acceleration G-force from 0.35g to 0.72g. To expedite the analysis turn-around time, a general parametric pan model embedded in I-DEAS solid modeling package has been developed to optimize the pan design, with the total pan volume and the vehicle ground clearance chosen as key constraints for pan optimization. Workable new pan alternatives are recommended.