Design Method And Dynamic Characteristic Study Of An Air Spring Type Semi‐active Hydraulic Mount

The powertrain and road are the two main vibration source of vehicle. the vibration isolation between the powertrain and the frame is the key point to improve the comfort and NVH performance of the vehicle. The dynamic characteristic of the mount is very important for the isolation performance of the powertrain mounting system, the vibration performance of the powertrain mounting system can be improved through optimum design of the mount component. This thesis deals with dynamic characteristic simulation and performs experiment on a semi-active hydraulic mount which was designed based on a passive hydraulic mount.Based on lots of related literatures, the mainly influential parameters of dynamic characteristics of hydraulic mount are discussed in this paper. The control principles, implementation methods and dynamic characteristics of familiar semi-active hydraulic mount are analyzed, on that basis, the feasibility of an air spring type semi-active hydraulic mount development is advanced.Based on a passive hydraulic mount, through reform design of internal structure to achieve adjustably of the dynamic characteristic. Based on solenoid valve design theory, by estimating the maximum air pressure and spring force, a direct operated solenoid valve is designed to control the open and close of the air chamber. While the solenoid valve is working, the valve head will seal up the air chamber with the action of electromagnetic force, and the dynamic characteristic of the mount is high stiffness and high damping, on the contrary, the dynamic characteristic of the mount is low stiffness and low damping.The static and dynamic characteristic experiments are implemented on the MTS831 vibration test platform. The static and dynamic characteristics at two different conditions (solenoid valve on current and with current) are tested and comparatively analyzed, and this is the basis of the dynamic characteristic simulation. According to VW 80101, high and low temperature environment simulation experiments are implemented with the solenoid valve, this ensures the fatigue requirement of the solenoid valve. NVH experiment is implemented with a vehicle which is mounted with the semi-active hydraulic mount, the vibration acceleration of the driver's seat and steering wheel are tested respectively under the idle condition and 100km/h ride condition. The test results show that the air spring type semi-active hydraulic mount can improve the isolation performance at different operating conditions.The mechanical and mathematical models are built respectively, simulation parameters are obtained through Fluid Structure Interaction (FSI) method, Analytic method and Parameter Identification method. On that basis, the dynamic characteristic simulation is implemented with the semi-active hydraulic mount, by comparing the test and simulation results, the simulation model of the mount is validated.