MOUNT ASSEMBLY WITH ELECTRO-HYDRO-PNEUMATIC SWITCHABLE DISPLACEMENT ELEMENTS

A system and method using a mount assembly for attaching a powertrain to a structural member of a vehicle. The mount assembly includes a first compliant member, a second compliant member, a first fluid chamber, a second fluid chamber, a third fluid chamber, a pressure compliant membrane, and a valve. A fluid conduit interconnects the first fluid chamber with the second fluid chamber to allow a fluid to pass from the first fluid chamber to the second fluid chamber. The third fluid chamber has an opening in communication with the second fluid chamber and a vent port. The pressure compliant membrane seals the opening between the second fluid chamber and the third fluid chamber. The valve selectively seals the vent port in the third fluid chamber. A first stiffness profile of the mount assembly is selected by actuating the valve to open the vent port. A second stiffness profile of the mount assembly is selected by actuating the valve to close the vent port.