Engine valve control system using a latchable rocker arm activated by a solenoid mechanism

The system (1) comprises a lash adjuster (5) mounted on a cylinder head, having a plunger, and a link pin (11) adapted to pivot on the plunger. An outer rocker arm (22) is supported on the link pin and engages an engine poppet valve (6). An inner rocker arm (18), which engages a cam lobe (20), has a saddle portion for contacting the link pin and rotates relative to the outer rocker arm. A biasing spring (26) contacts the rocker arms for forcing the outer arm into engagement with the popper valve and the inner arm into contact with the cam lobe. A sliding latch member (28) links the rocker arms for rotation in unison with the link pin about the pivot point in response to a force applied by the cam lobe to the inner arm, and for selectively unlinking the rocker arms for independent rotation. The latch member extends from one end of the outer arm at the poppet valve toward the link pin. An actuator arm (17) is pivoted at an end and contacts the latch member at a second end upon application of a force generated by a solenoid (16) electrically connected to and supplied by a control unit (51). The actuator arm is variable in length and has an arm spring (39) acting on it to bias the actuator arm to an extended position.