A valve actuator assembly for an engine includes a movable engine valve and a
movable
spool valve. The valve actuator assembly also includes a driving channel interconnecting
the spool valve and the engine valve and a first feedback channel and a second
feedback channel interconnecting the spool valve and the engine valve. The valve
actuator assembly includes an actuator operatively cooperating with the spool valve
to position the spool valve to prevent and allow fluid flow in and out of the driving
channel to position the engine valve. The valve actuator assembly further includes
a first on/off valve and a second on/off valve in fluid communication with the
first feedback channel and the second feedback channel to enable and disable the
first feedback channel and the second feedback channel, whereby the first on/off
valve and the second on/off valve control motion of the spool valve.
