Research On Parameters And Energy Recovery Efficiency Of Parallel Constant Pressure Source Regenerative Braking System

There are some issues about pure electric vehicle such as short drive range, short life of battery and so on, and recovery braking energy by motor. has problems of low efficiency in energy recovery and release and reliability is not optimistic. Aiming at improving the efficiency of regenerative braking energy recovery, the hydraulic hybrid technology can use in pure electric bus to extend mileage.The hydraulic hybrid technology has the advantages that it has higher power density and the recovery of brake energy is more sufficient. It is suitable for heavy load, frequent start-stop condition. And it has more superiority in theapplication of engineering machinery, heavy vehicles and the city bus. For modified Composite Regenerative Braking System for a parallel electric hydraulic hybrid bus, the paper mainly conducts the research from the following several aspects:The paper analyzes the structure and operating principles of parallel constant pressure source regenerative braking system for a electric hydraulic hybrid bus. Meanwhile, paper expounds several common braking conditions. Proposed a retrofit scheme for a parallel electric hydraulic hybrid bus. Based on the reform of the braking system the paper builds the kinetic equations of thesystem and mathematical models of the key components.Based on existing braking control strategies of hydraulic hybrid vehicle, the paper makes the control strategy on the composite system. According to the requirements of braking intensity, combined with the pressure of the accumulator, the state of flywheel, the efficiency of the secondary components andother parameters aiming at maximum energy recovery, the system achieved the goal that allocateand control the friction-hydraulic braking torque and the front and back brake force reasonably.Model and simulate the composite braking system. Apply the AMESim build the model of secondary components, power coupling element and other keyelements, and then establish the hydraulic regenerative braking system and vehicle hybrid system simulation model. Simulation according to actual working conditions and ECE-15 baking condition, analysis rationality of braking system control strategy; calculation of energy recovery according to accumulator pressure, battery status and the flywheel speed changes, the results show, a pure electric bus equipped with a hydraulic regenerative braking system, which can increase the driving range, reducing the depth of battery discharge, the battery life is also extended.Designed a principle experiment of hydraulic regenerative braking system under displacement of secondary components and volume of accumulator as the variable, collected experimental data and analyze. By comparing the experimental data and simulation results obtained the relationship between energy recovery efficiency and the parameters of secondary component, flywheel accumulator, and lay the foundation for further research on recovery efficiency of composite regenerative braking system..