| With the rapid development of the domestic economy and the rise of national income,automobile has gradually become popular as a consumer goods,and it has also had some negative effects.The most prominent three aspects are: environmental pollution,energy stress and brake safety.Therefore,it is of great significance to carry out in-depth research on the energy conservation and safety issues of automobiles.This paper is based on the modification of the traditional passenger car.It analyzes and determines the hub-type hydraulic regenerative braking system.According to the structural characteristics of the hydraulic pump/motor,a new type of hub-type secondary component—double vane pump/motor is designed.The hub pump/motor integrated design layout and a method of calculating the hub pump/motor and accumulator parameters.Aiming at the braking demand of the modified hydraulic hybrid vehicle,the coupling method of the traditional mechanical braking force and the regenerative braking force of the hub is analyzed,and a new composite braking system that can meet the requirements of the automobile braking regulations and recover the braking energy can be designed.According to the theory of automobile braking,the kinematics analysis is carried out for the single wheel and the whole body in the process of automobile braking.The reasonable distribution area of the braking force of the front and rear brakes is calculated by MATLAB,and the composite brake system is combined with the modified composite brake system.Energy recovery is analyzed in depth.Based on different angles,the ideal curve allocation strategy,fixed proportion distribution strategy,priority recovery allocation strategy and optimal performance allocation strategy are proposed respectively.In order to give full play to the energy saving advantages of the hub regenerative braking system,the optimal performance is selected after comparative analysis.The performance allocation strategy is used as the allocation strategy for the recovery of braking energy in the hybrid brake system of a hydraulic hybrid vehicle.Based on the optimal performance allocation strategy proposed in this paper,a hybrid vehicle composite braking system model is built on the AMESim platform,including hybrid vehicle model,tire dynamics and pavement model,aerodynamic model,vehicle speed sensor and minimum vehicle speed comparison model,pedal signal simulation unit,brake signal control unit,etc.The 22 typical braking conditions were selected for simulation to verify whether the composite braking system meets the national braking standard,and the influence of braking strength and initial vehicle speed on the energy recovery rate of the hub regenerative braking system is analyzed.The simulation results show that: 1)In the emergency braking mode,the optimal performance allocation strategy of the hybrid hybrid vehicle hybrid braking system proposed in this paper is in full compliance with the national braking regulations.2)In the light braking mode,when the initial speed of the car is constant,as the braking intensity increases,the energy recovery rate of the hub regenerative braking system gradually decreases,and the actual recovered energy is gradually reduced;when the braking intensity is constant As the initial speed of the car increases,the energy recovery rate of the hub regenerative braking system gradually decreases,but the actual recovered energy gradually increases.3)In the normal braking mode,when the initial speed of the car is constant and at medium and low speeds,as the braking strength increases,the energy recovery rate of the hub regenerative braking system gradually decreases,and the actual recovered energy is also gradually reduced.When the initial speed of the car is constant and at high speed,as the braking strength increases,the energy recovery rate of the hub regenerative braking system gradually decreases,but the actual recovered energy remains unchanged due to the maximum value;At certain times,as the initial speed of the car increases,the energy recovery rate of the hub regenerative braking system remains basically the same,but the actual recovered energy gradually increases until the maximum value remains unchanged.4)In the standby braking mode,the reference value of the braking performance when the brake is stopped under the abnormal braking condition is given.In this paper,the research on hydraulic hybrid hybrid brake car provides reference and guiding significance for the development of new energy-saving and emission-reducing vehicles that use recycled braking energy. |
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