Electro-hydraulic Integrated Braking System For Hybrid Electric Vehicle

Due to environmental pollution and energy shortage problem, much attention has beenpaid to hybrid and pure electric vehicles, which has become the hot topic in the study of theworld auto industry. There are two factors, which are limited driving course and the initialhigh cost, influencing the development of pure electric vehicles to industrialization. Andcombining traditional car’s long trip journey advantage with pure electric vehicle’s energyconservation and environmental protection advantage, a hybrid car has achieved initialindustrialization. Hybrid electric vehicle’s technology development has entered the crucialstage.As a key technology of hybrid cars, regenerative braking technology can recycle brakingenergy, save fuel effectively, and extend the mileage, which is one of the important means forhybrid electric vehicles reducing fuel consumption. Hybrid car is the transition from thetraditional fuel vehicles to all-electric vehicles, and its regenerative braking technology mustbe combined with the traditional hydraulic braking technology, which will produce a newtechnology--the electro-hydraulic integrated brake technology.Based on traditional fuel to hybrid prototype for reference, in order to improve therecovery of braking energy as the goal, the reasonable distribution of the vehicle brakingforce and braking security and other key problems are studied. Using AMEsim andMatlab/Simulink simulation platform to built the integration of the vehicle brake systemmodel and the integration of the braking system control strategy, and to conduct jointsimulation model. This paper’s main research work includes the following four aspects:(1) According to the prototype and electro-hydraulic integrated functional and structuralcharacteristics of the braking system, designation of motor regenerative braking system isanalyzed respectively with the structure and working principle of ABS hydraulic brakesystem, and then determine the prototype of integration structure design scheme of brake system.(2) Based on the prototype of hardware structure scheme and the traditional hydraulicbraking control theory, the braking force distribution strategy, motor regenerative brakingstrategy, regenerative braking and ABS anti-lock coordinated control strategy andcomprehensive braking control strategy of the electro-hydraulic integrated brake system arestudied. Proposing the constant ratio of the vehicle braking force distribution strategy inparallel based on fuzzy control, the composite constant charging current and maximum powermotor PID control strategy, regenerative braking coordination with ABS logic thresholdcontrol strategy.(3) Using the AMEsim simulation platform, vehicle brake system integration model isestablished. Car’s key components and the integrated control strategy model of brakingsystem are established in Matlab/Simulink model. Then, set up a joint simulation platform,the simulation and analysis for subsequent laid the foundation platform and model.(4) Select the appropriate evaluation indicators and simulation working condition, to testthe integration of braking system and its control model with conventional braking conditionand emergency braking condition. Simulation results show that the integrated braking systemand its control strategy can guarantee the vehicle braking performance and stability, andgreater degree of recycle braking energy.