Lost-motion variable valve actuation system with valve deactivation

A valve actuation system, comprising:

• a bearing element having first and second opposed bearing surfaces and being coupled to an adjustable hydraulic tappet by a connecting arm;
• a cam configured to slidably engage the first bearing surface of the bearing element to impart motion to the bearing element and thereby rotate a rocker arm when the bearing element is positioned between an eccentric portion of the cam and a rocker pad formed on the rocker arm such that the second bearing surface of the bearing element slidably engages the rocker pad;
• an engine valve coupled to the rocker arm such that rotation of the rocker arm in a first direction is effective to open the engine valve and rotation of the rocker arm in a second direction opposite from the first direction is effective to close the engine valve;
• a trigger valve that allows the adjustable hydraulic tappet to be selectively drained of and filled with hydraulic fluid such that a position of the connecting arm and the bearing element can be adjusted;
• a spool valve having a first configuration in which the adjustable hydraulic tappet is placed in fluid communication with the trigger valve such that the engine valve is activated and a second configuration in which the adjustable hydraulic tappet is hydraulically disconnected from the trigger valve and is instead placed in fluid communication with a hydraulic accumulator such that the engine valve is deactivated;
• and
• a solenoid configured to selectively place the spool valve in the first configuration or the second configuration.