Abstract: The present invention is a fluid which exhibits excellent electrorheological properties at low current densities, at high temperatures, and in the complete absence of absorbed water or water of hydration. In a preferred embodiment, the fluid comprises lithium hydrazinium sulfate dispersed in silicone oil, and in the presence of an appropriate suspension stabilizing agent.

Abstract: The mount has variable volume fluid chambers interconnected by fluid passageways and containing electrorheological fluid. Valves are arranged in series with a plurality of the passageways. Each valve has a flow area greater than that of the passageway in series therewith. Energization of a valve generates an electrical field effective to so increase the apparent viscosity of the fluid within the valve as to prevent fluid flow through the passageway in series with it. Selective energization of the valves, by suitable controls associated therewith, varies the frequencies at which fluid inertia forces cause the mount to undergo abrupt changes in dynamic stiffness. The valves may be located upon opposite sides of a central mount section through which the chamber connecting passages extend. Electrode elements of the valves are preferably so shaped as to minimize fluid drag and electrical concentration.

Abstract: The mount includes first and second chambers containing water, glycol or similar conventional hydraulic fluid of low viscosity, and at least a third chamber containing electrorheological fluid that is used to "tune" the frequencies at which the mount experiences abrupt reduction of dynamic stiffness. The third chamber is contiguous with one of the first and second chambers, and with one end of an inertia track passageway whose opposite end is contiguous with the other of the first and second chambers. Energization of an electrode-type of valve associated with the third chamber produces a high voltage electrical field and fluid solidification within the third chamber. Pressure pulses are transmitted through the third chamber only when the valve is de-energized. The valve has electrode elements which may be of flat or spiral shape. The mount may include additional valved chambers, and additional passageways which preferably are of differing sizes.