US Patent 7765972 Fully variable mechanical valve train in an internal combustion engine

A variable mechanical valve train for actuating a valve in an internal combustion engine includes a two-part follower operatively coupled between a cam shaft and a valve, so that the follower: in a fully-activated mode, causes a maximum lift of the valve in response to a rotation of the cam shaft; in a partial load mode, collapses partially so as to cause a partial valve lift during the rotation of the cam shaft; and in a deactivated mode, collapses in response to the rotation of the cam resulting in no valve lift.