Analysis on energy recovery efficiency of hydraulic regenerative braking system

GUO Yang-yan1，NING Xiao-bin1，WEI Dong2

（1. Institute of Vehicle Engineering，Zhejiang University of Technology，Hangzhou 310014，China；2. Zhejiang Geely Automobile Research Institute Co.，Ltd.，Hangzhou 310000，China）

Abstract：Aiming at solving the problems of the short driving range and the difficult of battery charging，the regenerative braking system of pure electric vehicle was studied，a constant pressure hydraulic regenerative braking system with flywheel was established after comparing several hydraulic regenerative braking schemes. In order to improve the energy recovery efficiency of hydraulic regenerative braking system that established for electric vehicles，the experiment and simulation analysis on AMESim was undertaken by using the displacement of pump/motor and volume of the accumulator as variables，through the comparison of simulation analysis and experiment，the best parameters matching was found. The results indicate that the energy recovery efficiency of this system changed while the size of the accumulator volume or the type of hydraulic pump/motor displacement is different，the larger displacement of pump/motor is the more energy recovery，but with increasing the displacement of pump/motor the resistance is also increased，the energy recovery efficiency decreases when displacement of pump/motor larger than a certain value，larger volume of the accumulator，the more energy is recyclable. Study of this system is worth learning，it can provide a reasonable parameter match for the electric vehicle hydraulic regenerative braking system.

Key words：regenerative braking；pump/motor；accumulator