Simulation and intelligent cooperation control strategy of double-pump hydraulic system for automatic transmissions

Double-pump(mechanical driven oil pump and electric driven oil pump) hydraulic system is a new solution for state of art automatic transmission(AT) to satisfy hybrid vehicle functions and also improving system efficiency. In this paper, the vehicle dynamics model was built, then a mathematical model of transmission cooling and leakage flow was built. Based on the cooling and leakage flow requirements, intelligent cooperation control strategy of the double-pump hydraulic system was then developed aiming at energy saving. Driving simulation in various typical driving cycles indicated that the double-pump hydraulic system with optimized control strategy can get 2.4% fuel economy improvement in comparison to the conventional one pump hydraulic system. The findings in this paper have a certain value in intelligent control theory study and engineering application.