Abstract: A valve control system for an internal combustion engine including a poppet valve (21) and high lift (15) and low lilt (31) cam lobes. A latchable rocker arm includes an outer rocker arm (33) and an inner rocker arm (35), and a slider mechanism (37) which is biased by a spring (67) to the high lilt mode (FIG. 1). An actuator assembly (27) includes and arm (103) biased by a spring (101) into engagement with the slider (37), biasing the slider toward the unlatched (low lift) mode (FIG. 2 ). The actuator (27) includes an electromagnetic coil (83) which moves an armature (87) into engagement with the arm (103), biasing the arm in opposition to the force of the actuator spring (101), but aided initially by the force of the slider spring (67).

Abstract: An actuator for a phase change device of the type wherein a phase change is effected between an input member and output member in response to the axial movement of an advancing member interconnecting the input member and the output member, and wherein such axial movement is effected by retarding the rotation of a drum member engaged with the advancing member. The retarding force is provided by an electromagnetic wet brake mounted in juxtaposition with a brake disk surface formed on the drum in a fixed angular position but capable of limited axial movement relative to the brake disk surface.