Circuit/System Description

The four state switchable engine mount (also known as vacuum switchable engine mounts) provides the ability to change the stiffness of the engine mount as a means to reduce engine vibrations felt by the driver. The four state switchable engine mount characteristics are controlled by applying vacuum or atmospheric pressure to the bounce and idle ports of the mount; vacuum is supplied to the mount by activating a solenoid. Applying different combinations of vacuum or atmospheric pressure determines the mount stiffness. The commanded state of the mount is dependent on various vehicle operating conditions, such as engine speed, transmission gear, and vehicle speed. The engine mount solenoid valves control the switchable engine mounts by providing vacuum when desired. The engine mount solenoid valves are provided battery voltage. The chassis control module provides ground to activate the engine mount solenoid valves.