The Study Of Vehicle’s Regenerative Braking System Based On Input Split Hydraulic Machinery

Hydraulic regenerative braking technology which has advantages of higher powerdensity, stronger charge-discharge capability and higher reliability is a significant way ofimproving vehicle’s energy efficiency and reducing emission. The hydraulic regenerativebraking system based on HMT which adopts hydraulic pump/motor and hydraulicaccumulator as energy conversion and storage units is a feasibility transmission scheme. Itcan improve energy storage efficiency and reduce vehicle fuel consumption effectively.The paper aims at the hydraulic regenerative braking system based on HMT to carryout the study of its transmission schemes selection and characteristics analysis,components selection and parameters matching, control strategy making and simulationmodels establishing. The main content includes:(1)The speed characteristic, torquecharacteristic and power characteristic of potential transmission schemes for input-spiltand output-spilt HHV is analyzed, and a appropriate input-split transmission schemeaimed at regenerative braking is proposed, the HHV operating characteristics are studiedunder regenerative braking and auxiliary driving conditions.(2)Using the matchingsample vehicle parameters, the design parameters and the type of hydraulic pump/motor,hydraulic accumulator are determined and calculated in the hydraulic regenerative brakingsystem based on HMT for input-split HHV.(3)A reasonable control strategy applied toregenerative braking system based on HMT for input-split HHV is developed andproposed by making use of mathematical methods. Braking torque distribution controlmodel which is established in MATLAB/SIMULINK simulates and analyzes the distributionrule of braking torque at different braking modes.(4)The simulation models of thehydraulic regenerative braking system are established, analysis of regenerative brakingeffectiveness is carried on under different urban conditions, the results show that the effectof energy recovery and saving is the most significant at mild braking mode, vehicle canachieve the maximum of energy recovery, energy storage efficiency can reach above40%.