Simulation And Experimental Study On Vibration Reduction Characteristics Of Semi Active Engine Mount

With the continuous progress of science and technology and the rapid improvement of the vehicle industry,people have increasingly high requirements for vehicle performance.As one of the indicators of ride comfort,vehicle vertical vibration has attracted wide attention.The bumps and vibration problems caused by the car running on uneven roads will directly affect people ’s ride experience.As a key component in the vibration isolation system,the optimal design of the engine mount will bring a qualitative leap to the solution of the vehicle NVH problem.The engine mount is an important connector in automobile parts.During the normal driving of the vehicle,it is necessary to minimize the adverse impact caused by the downward transmission of vibration from the powertrain system and road roughness.At present,the ideal mount should have high stiffness and large damping in the low frequency band,and low stiffness and small damping in the high frequency band.Because the traditional passive mount will have high-frequency dynamic hardening effect,resulting in poor vibration isolation,and the active mount needs to use an external control system,resulting in expensive costs,so semi-active mount has become the current research focus.It has the characteristics of good performance and appropriate cost,and can meet the requirements of better vibration isolation and absorption.In this paper,based on the engine mount project being developed by an enterprise,the modeling method combining the fluid structure coupling finite element method and the lumped parameter model method is adopted to study the problems encountered in the forward development of the mount,and propose reasonable and effective solutions.The following are the general contents:First of all,on the basis of reading a large number of domestic and foreign literature,combined with the semi-active mount being developed by a company,we construct its structural framework,analyze its working principle,build a lumped parameter model related to the mount,and analyze the extraction method of key parameters required by the model,providing a theoretical basis for subsequent simulation and experiments.Then,according to the structural parameters of the suspension sample,the three-dimensional model of each component is drawn.It is imported into the pre-processing software to complete the grid division under the solid,liquid and gas states.Soon afterwards,the material properties,loads,boundary conditions and constraint conditions are added to the post-processing software to complete the fluid structure coupling simulation,and the hysteresis curve method is used to preliminarily obtain the dynamic stiffness and damping angle of the suspension system.After the finite element simulation of the mount is completed,the test plan is proposed,the fixture matching the sample is designed,and the relevant tests of the static and dynamic characteristics of the semi-active mount are completed under the two states of power off and power on of the solenoid valve.Through the comparison between the simulation and the test results,the reliability of the finite element model is verified,and the correct model is established for parameter identification.Then,according to the mechanical characteristics of the semi-active mount,the modeling is completed in the AMESim platform.The fluid structure coupling finite element analysis method is used to extract the key parameters such as the rubber main spring,the volume stiffness of the upper and lower liquid chambers,the fluid inertia coefficient,and the damping coefficient.After the parameters are brought into the lumped parameter model,the simulation is completed.The data is processed in MATLAB software,and the dynamic characteristics are analyzed by drawing the dynamic stiffness and damping angle curve of the mount under the soft and hard modes,The simulation results of two different methods are compared with the test results to verify the accuracy of the model.On the basis of verifying the accuracy of the model,the parametric analysis of the mounting system is further carried out.The influence of the key structural parameters in the lumped parameter model on the dynamic characteristics is understood by adjusting the key structural parameters in the lumped parameter model,which provides theoretical help for the subsequent development,improvement and optimization of the semi-active hydraulic mount.The results show that the fluid structure coupling lumped parameter modeling method has high accuracy.It can not only be used to analyze the influence of a certain key parameter of the mount on the dynamic characteristics,but also provide a modeling basis for engine mount optimization.Using this method can greatly save research and development costs and improve research and development efficiency.