Design of hydraulic control system for a new energy vehicle hybrid drive system

Abstract

An efficient and energy saving hybrid drive system was developed and applied in a new energy vehicle to meet global demands for vehicle energy consumption and exhaust emissions reduction. This new system as a power train is composed of an e-CVT (electric coupled CVT with a motor and a generator built-in), an engine, an Integrated Power battery and a Power Control Unit. The hydraulic control system integrated in the e-CVT system was developed for realizing and supporting the different modes of the hybrid drive system. In this system, a pump driven by the input torque from engine and another pump driven by a small power electric motor as oil source to meet the flow rate demands in each vehicle operating mode. Hydraulic Control Module integrated design, to implement the required flow distribution and pressure control for built-in motor and generator cooling, some needed gears and bearings lubrication, clutch control and clutch cooling. Motor oil cooling system designed to meet the real-time cooling flow requirements of motor. Dynamic simulation and test were done to verify the design is reasonable.