US Patent 7600498 Internal combustion engine with gas exchange valve deactivation

An internal combustion engine with selectively deactivated intake and/or exhaust valves includes a fulcrum plate having a through hole with a slidable plunger supporting a pivot ball that engages an associated rocker arm. A solenoid positioned above the rocker arm cover is directly coupled to a latching mechanism that either allows or prevents sliding movement of the plunger to selectively deactivate associated intake/exhaust valves. When in the valve activated position, the rocker arm pivots about the pivot ball and opens the valve. When in the valve deactivated position, the plunger retracts at least partially into the fulcrum plate so that the rocker arm motion is insufficient to open the associated valve. A lost motion torsional spring acts on the plunger to provide an opposing force to the rocker arm and to return the plunger to the valve activated position during the base circle portion of camshaft rotation.