Hydraulic mount with magnetorheological fluid

The present invention pertains to a hydraulic mount, particularly adapted for motor vehicle engine and powertrain mount applications, including a magnetorheological (MR) fluid which is forced to flow through an annular path between mount fluid chambers and under the influence of a controllable magnetic field. A hydraulic mount for automotive engine and powertrain applications includes an elastomer body, a base and a partition interposed the body and the base to form a fluid-pumping chamber and a reservoir. Circumferentially spaced axial extending holes or slots or an annular orifice track are formed in the partition together with a magnetic coil operable to impose a magnetic field on the holes, slots or orifice track to control the shear properties of a magnetorheological (MR) fluid in the pumping chamber and reservoir. An elastomeric decoupler member is in communication with at least one of the pumping chamber and the reservoir to reduce the mount dynamic stiffness for isolating low-displacement relatively high-frequency vibrations. Vibrations of multiple frequencies may be isolated by tuning the mount with a controller.