The Comfort Study Of Electro-hydraulic Compound Brake System For Electric Vehicle

With the rapid development of automobile industry, the domestic fuel consumption is too large and environmental pollution is worsening. for nowadays, Development and production of low-power and low-emission or zero-emission electric vehicles, is car industry hotspot. Research and development of pure electric vehicles as the representative of the new energy vehicles, is an effective means to alleviate the energy and environmental pressures, is the inevitable choice for the automotive industry’s sustainable development. Regenerative braking technology as one of the key technology of automobile energy saving, not only affect the braking energy recovery, but also affect braking process of comfort.The regenerative braking system of the pure electric vehicle is composed of the motor braking system and the mechanical hydraulic braking system, and it is a multi and dynamic transformation system. To achieve efficient recovery of braking energy during braking and ride comfort the premise is to have a good electro-hydraulic braking system and brake control technology.In this paper, a Chang’an pure electric vehicles as the research object, to improve ride comfort during braking, study of pure electric cars electro-hydraulic braking system.a new system of electro-hydraulic braking system for electricity vehicle is put forward.Theory analysis and modeling. simulation and performance evaluation of the electro-hydraulic braking system is completed.The main tasks are as follows:(1)Through the comparison of the typical braking force distribution strategy, under the premise of satisfying the braking regulations and braking mechanics characteristics, distribute front and rear shaft braking force, motor and hydraulic braking force of front axle rationally. Determine the braking intensity threshold, developed a brake force allocation under each brake intensity control strategy.(2)Through the analysis of the characteristics of the motor brake system and hydraulic brake system, based on braking force allocation strategy, put forward the mechanism of coordination motor braking force and hydraulic braking force change rate of the control strategy. Aiming at the condition of the two system features different, control all kinds of brake mode to switch smooth transition, realization of smooth braking process.(3)Based on the ABS hydraulic control unit, a new type of hydraulic braking system is designed.In order to meet the simulation platform requirement of the Electro-hydraulic braking system. Based on AMEsim and Matlab/simulink CO-simulation platform to solve the problem,structure program based on co-simulation platform,build vehicle model, tire model and the control strategy model based on Matlab/Simulink/Stateflow. Build hydraulic braking system in AMEsim.(4)Based on AMEsim and Matlab CO-simulation platform, off-line simulation analysis for the braking performance of new hydraulic braking system, and its control strategy for smooth braking performance. And compared test prototypes data and simulation data.The simulation results show that the vehicle brake comfort has certain improvement.In this paper, designed new electric vehicle hydraulic brake system and build the brake mode, put forward electro-hydraulic braking system of the brake mode switching control strategy and control methods.to verify the proposed control strategy for braking ride comfort has some improvement. It provides a theoretical basis for the realization of the braking process ride comfort.