Study on Hydraulic System for Full Hybrid Transmission

Design method of hydraulic system of full hybrid transmission was analyzed. At first, oil volume flow and pressure requirement was confirmed according to the vehicle control strategy. Mechanical gear pump and electric pump were used to supply oil flow for all driving modes. Self-adapted pressure regulation circuit was designed to supply high pressure oil for brake engagement. Structure dimension of valves and cooling orifices was designed by theoretical calculation. Cooling flow can be distributed proportionally among electric motors and planetary gears. Full hybrid vehicles can achieve pure electric driving, and most of the braking energy recovery, with significant oil-saving efficiency. Toyota Motor Company's single-mode hybrid system and GM's two-mode program and increase electric power system as the representative of the power shunt, which led to the development of international hybrid technology, so the full of the hybrid system is becoming The main technical solutions at the present stage of new energy vehicles. Power shunt hybrid system is hybrid solution full of a high electric power, the motor integration is in the transmission, during operation of the motor must be forcibly cooled, in order to maintain the thermal equilibrium state of the motor. Therefore, in addition to the product development process need to develop core power split planetary gear mechanism and control strategies also need to study. Heat balance of power system control technology, including determine the requirements of cooling flow of the power system, design technology solutions of hydraulic systems and optimize all the oil cooling flow distribution. Taking a hybrid split transmission as the analysis of object, study design techniques of full hybrid integrated hydraulic system.