The Structural Design Of A Mount With Electrorheological Fluids And Semi-Active Control Simulation Analysis

Along with the improving standard of living, the higher comfort performance of automobile are required, and become an important index when a car are evaluated. Meanwhile, governments are stricter with fuel economy and automobile emissions because of the energy shortage and the deterioration of the environment. The modern car becomes small, light and economic. Thus Engine vibration contributes greatly to overall noise and vibration.Engine mount is a component, designed for isolating vibration transfer between the engine and passenger compartment. At present, engine mount is not only popularly applied to cars, but also applied to passenger cars, trucks, ships and airplanes. But the conventional passive hydraulic mounts have some defects. For example, within the range of high frequency, liquid-column-resonance tends to take place because of the lag of response. The high dynamic stiffness deteriorates the isolation performance. To avoid this, conventional passive hydraulic mounts have to select low viscosity liquids (such as alcohol, silicone oil, antifreeze solution) which is filled in two cambers of the mount. But low viscosity liquids mean low isolation performance. Conventional mounts can't work effectively within a wide range of frequency. One of attractive approaches to attenuate unwanted vibration of dynamic systems is to utilize an electrorheological (ER) fluid, which undergoes instantaneous and reversible change in rheological properties when applied electric potentials.This paper presents a new type of electrorheological mount. Its dynamic performance is investigated both in experimental part and theoretical part. From the development of engine mount and its researching course, presents and discusses the development, status and the engineering application of electrorheological fluid, expatiates the purpose of this paper, and list the main content which should be researched.Then, based on the compose of electrorheological fluid and the requirement of performance, use a kind of kaolinite/dimethylsulfoxide/carboxymethyl starch nanocomposites as the dispersed phase, use silicone oil as the base fluid, confect a kind of electrorheological fluid. Test the performance of EFR when different electric fields are exerted. Through the research of the mechanism of electrorheological fluid, analyze the shear yield stress of electrorheological fluid in the electric field. Then, the parameter of the EFR can be calculated.Analysis is emphasized on flow pattern in inertia track for fully play EFR's rheological properties. By establishing the semi-active engine mount internal pressure-movement equation, the damping force expression can be obtained when the fluid flows though the inertia track. So, frame parameters are reckoned. According to the character of engine's vibration, design the structure of electrorheological engine mount and ER fluids are incorporated into hydraulic mounts.Through analyzes the ERF engine mount the structure and the principle of work, establishes the ERF engine mount model and the mathematical model, and obtains the dynamic stiffness, damping force expression. Then the simulation is carried to the EFR engine mount dynamic characteristic. The dynamic performance of the hydraulic mounts is changed with the voltage of the electric field and structure parameters of flow restriction elements. The results show that the EFR engine mount 's dynamic performance can be shifted with the change of engine speed, so it's performance of decreasing and isolating vibration is boosted . The EFR engine mount has low stiffness within the rage of high frequency. Therefore it is feasible to change the EFR engine mount vibration isolation performance by changing the dynamic characteristic of through changing inertia track areas.Adopting ON-OFF to control the inertia track areas, Simulation and computation of mount dynamic characteristics are done by MATLAB. The results show that the ERF engine mount has ideal isolation performance with the different frequencies. Within the range of low frequency and large amplitude, engine mount should have adequate stiffness and lager damping; on the other hand, with in the range of middle and high frequency, the mount is expected to have small stiffness and small damping to decrease vibration and noise transferred to the passenger compartment.ERF engine mount is the developing trend for engine vibration isolation while representing the future mount with board market foreground, thus this research is in engineering practicality worth.