Evaluation Of Engine Mount Vibration Isolation Performance Based On Dynamic Force Measurement

At present,the vibration acceleration measurement method is used to study the vibration isolation performance of automobile engine.The method measures the vibration acceleration of both ends of the mounts(side of engine and chassis),and then evaluates and studies the vibration isolation performance by using the method of obtaining the transfer rate.This paper discusses a method to study and evaluate the vibration isolation performance of automobile engine by using the suspension dynamic force.Study and evaluate the vibration isolation performance by directly measuring the support reaction force of the mount in the engine working processing.Accordingto a 2007 fivemanual zunchi vehicle as study object.Firstly,the Vibration module of Adams software is used to simulate the engine mount system of the vehicle.Through modeling,setting the vibration parameters and boundary conditions,calculating and applying the driving force,simulation and so on,the natural frequency and the energy decoupling degree of the model are obtained.Simulation model and measured the support reaction force of the front and rear mount,provides theoretical support for the following vehicle test.And then use the engine mount force measurement system which is developed by another student,and add the traditional vibration acceleration measurement system,completed the vehicle test.The test including the calibration test,lifting machine no-load test,road test three contents,and the road tests were carried out in 24 cases.In the course of the experiment,six signals were recorded and storage simultaneously:the support force of the front and rear mount and the vibration acceleration at both of the active and passive side.After the test,the RMS value analysis and power spectrum analysis are carried out on the mount dynamic force signal under different working conditions,and the vibration acceleration is compared with the same condition.Data processing result display: At present,the vibration acceleration transfer rate can be trusted to evaluate the vibration isolation performance of the engine mount under netrual condition.Mount support force can be used as an auxiliary evaluation index.But at the road test,the vibration acceleration transfer rate are not suite able to evaluate the vibration isolation performance,but support force of the mount evaluation is credible.In addition,in the road test,the suspension force and vibration acceleration transfer rate can be used same to evaluate the vibration isolation performance of the mount,by this way,the evaluate result can be more comprehensive.The research results of this paper can find the "blind spot" in the frequency domain of vibration acceleration by comprasion with the mount force,this results have the reference value in the processing of design and match of engine mount.