| The decoupling brake-by-wire system realizes various braking functions of the automobile by controlling the on and off of the solenoid valve.The responsiveness and accuracy of the brake system are directly determined by the performance of the solenoid valve.Therefore,studying the performance of the solenoid valve has important engineering application and theoretical research value in improving the overall performance of the decoupled brake-by-wire system.For the solenoid valve in the decoupling brake-by-wire system,the flow field characteristics,static characteristics and dynamic response characteristics of the solenoid valve are studied in detail,and the influence factors of the solenoid valve on its performance characteristics are numerically analyzed.The main work of the thesis is as follows:1)Theoretical analysis of the decoupling brake-by-wire system and the solenoid valve multi-physics coupling model.Briefly describe the composition,structure and working principle of the decoupling brake-by-wire system and the solenoid valve,and analyze the performance requirements of the solenoid valve in the braking system.Discusses the solenoid valve flow characteristic test,electromagnetic force measurement test and dynamic response test methods,and analyzes the change law of solenoid valve related tests.According to the physical model,the solenoid valve module is divided into electric field,magnetic field,motion field and flow field,and the four fields are analyzed theoretically.2)The finite element calculation method used to predict the flow field characteristics of the solenoid valve is studied,and the influence of the filter structure and the solenoid valve structure on the flow field characteristics is analyzed.Using porous media instead of the filter fluid domain model,the entire fluid domain of the solenoid valve was simulated and analyzed,and the error between the simulation results and the test results was within 10%,which verified the reliability of the porous media instead of the filter model.The influence of the filter mesh number,inlet diameter and incident cone angle on the flow field characteristics of the solenoid valve is analyzed.The results show that the larger the filter mesh number,the greater the throttling effect of the solenoid valve,which acts on the solenoid valve spool.The smaller the hydraulic power,and the reasonable selection of the inlet diameter and incident cone angle can effectively improve the internal flow field.3)A simulation model of the static characteristics of the solenoid valve was built,and the influence of the structure of the solenoid valve on the static characteristics of the solenoid valve was analyzed.The calculation of the electromagnetic force of the solenoid valve is theoretically analyzed,and the influence of variables such as the working air gap,current,number of coil turns,and the ratio of moving and static iron pull-in area of the solenoid valve on the static characteristics of the solenoid valve is studied by using the finite element method.The results show that the larger the number of coil turns,the smaller the working air gap,and the closer the ratio of current to pull-in area is to 1,the static characteristics of the solenoid valve can be effectively improved.The changes in the number of coil turns and the excitation voltage have the most significant impact on the static characteristics of the solenoid valve.4)Based on the differential equation of solenoid valve coil current and the motion equation of solenoid valve motion components,a solenoid valve dynamic response simulation model was built on the Matlab/Simulink simulation platform,and the effect of solenoid valve structure and armature parameters on its dynamic response was analyzed.The influence of variables such as the mass of moving components,spring stiffness,and excitation voltage on the dynamic response of the solenoid valve is studied.The results show that the changes of excitation voltage and the number of coil turns have more significant response to the dynamic response of the solenoid valve. |
