| In recent years,with the development of new energy automobiles and active braking technology,the vacuum required for a vacuum assist braking system cannot be provided by the engine intake manifold,and the existing automotive vacuum pump have room for improvement in response speed,volume and power consumption.Therefore,the further study of automotive vacuum pump has important scientific significance and application prospects.Aiming at the active braking in automobile braking system,a type of two-stage tandem diaphragm vacuum pump with a linear drive of electromagnetic actuator is proposed,it has the advantages of fast response speed,small volume,low power consumption,working frequency that can be quickly adjusted in real time,etc.The main work of this paper is as follows:(1)The structure design and research of electromagnetic vacuum pump.According to the functional requirements of the electromagnetic vacuum pump and the type selection of its main components,this paper expounds and analyzes the working principle of a two-stage tandem vacuum pump,and then puts forward a structural design scheme.(2)The establishment and analysis of electromagnetic vacuum pump simulation model.Based on the basic differential equation,the simulation model is established by Matlab /Simulink,and the displacement variation of reed valve set is analyzed,which lays a foundation for the determination of the optimal stiffness variation range in the later structural optimization of reed valve set.(3)The structure optimization of reed valve set.The relation between reed valve's stiffness and structural parameters is established by combining interpolation method and finite element method.The relation between reed valve's equivalent mass and structural parameters is established according to reed valve structure.And the optimize parameters of reed valve set are determined,on this basis,the optimization design of reed valve set is carried out by genetic algorithm with the objective of maximum vacuum degree.(4)The development,testing and result analysis of electromagnetic vacuum pump principle sample.The electromagnetic vacuum pump principle sample is processed and assembled and its control system is designed,so as to build a vacuum test platform.The feasibility of the design scheme and the accuracy of the simulation model are verified by experiments.The structural improvement schemes are proposed for the factors which influence the extraction performance,and the corresponding experimental researches are carried out.Based on the test,the law of energy consumption changing with working frequency is analyzed.(5)The application of electromagnetic vacuum pump in automotive braking system.Aiming at the braking assist function expected to be realized in this paper,a structural design scheme of active vacuum booster is proposed and then the working principle is analyzed,the key parameters are determined,the control strategy is developed.After that,the matching of electromagnetic vacuum pump is studied,and the characteristics of the active vacuum booster are simulated and analyzed to verify that the active vacuum booster meets the braking requirements. |
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