Magnetorheological semi-active mount system for engines: Prototyping and testing

In order to maximize the controllability of magnetorheological (MR) mount for engines, a novel (MR) mount with an internal bypass (MRM-IB), which provides particular advantages of large dynamic stiffness range, small field-off dynamic stiffness and long available stroke under full vibration frequency range, is proposed and investigated in this paper. The proposed MRM-IB consists of a main rubber spring unit for supporting static load and a MR damping unit for mechanical energy dissipation. The MR damping unit is composed of a piston assembly, a MR fluid chamber and an annular MR fluid channel sandwiched by two concentric cylinders, that is, the inner and outer cylinders. Electromagnetic coil winding is wound on the outside of the inner cylinder and continuous damping/dynamic stiffness of the MRM-IB is tuned by the applied current in the coils. Structural principle of the magnetic circuit of the proposed MRM-IB is validated and analyzed, and the mathematical model of the controllable damping force is then established. In addition, a frequency-based piecewise controller and a fuzzy controller for a specific MR semi-active automotive mount system are designed, and the theoretical simulation and the experimental tests of the system are conducted, compared and analyzed.