Research On The Vibration Isolation Of Vehicle Hydraulic Engine Mounting System

With the great demand on the riding comfort, hydraulic engine mounts are increasingly used on middling or high-class cars, taking the place of traditional rubber mounts. Nowadays hydraulic mounts start to be used on passenger cars, but researches on this field are very few. In order to finding new problems, in the thesis, vibration isolation performance of the engine mounting system of the light passenger car, Transit, was analyzed through experiment and simulation.Firstly, based on the analysis of hydraulic mount's structure, operating principle, ideal dynamic characteristics and the testing results of dynamic characteristics, its vibration isolation performance was incipiently evaluated. The dominant excitation of diesel engine was figured out through experiment. The vibration isolation characteristic of the hydraulic mounting system, was studied by modal test and some positive advices were given.Secondly, according to a six degree of freedom mechanical and mathematic model of the passenger car's engine mounting system, system's vibration was simulated by Matlab/Simulink under different operating conditions. The different vibration isolation performance between hydraulic and rubber mounting system was analyzed. Mounts' parametric and orientation influence on the system's vibration was clearly showed.Finally, with an experimental study on the engine mounting system under different operating conditions, vibration isolation performance between hydraulic and rubber mounting system was further analyzed. Frequency spectral analysis on the system's vibration was given under the startup condition. A further study on the vibration isolation characteristics of Transit passenger car's mounting system was carried out and some optimization suggestions were provided.