Energy Consumption Analysis of Hybrid Continuously Variable Transmission Based on Electric Oil Pump

In order to develop the hydraulic system of CVT-based hybrid transmission, several oil supply schemes in the mass production hybrid vehicles based on CVT are analyzed and compared with the scheme proposed in the paper. Considering the demands of transmission to implement electric drive mode and decreasing energy consumption of hydraulic system, the electric oil pump supply plan is put forward. Simulations are designed to compare the energy consumption of different scenarios. Results show that the electric oil pump can reduce much more energy consumption than other schemes. To further verify the energy-saving effect of the electric oil pump scheme, a hybrid CVT based on it is developed. The efficiency of the transmission based on the electric oil pump and the mechanical oil pump supply schemes are tested by a bench test at 1 500 r/min. The experimental data show that the electric oil pump scheme can significantly improve the transmission efficiency compared with the mechanical oil pump supply scheme. When the input torque of CVT is 150 N•m, the electric oil pump scheme can improve the transmission efficiency by 3.72% compared with the mechanical oil pump. Finally, a test car equipped with the hybrid CVT is developed to test, and the results show the feasibility of the electric oil pump scheme. © 2018 Journal of Mechanical Engineering.