An engine valve actuation system may include an actuation assembly having a body,
a slidable piston, and first, second, and third chambers defined between the piston
and the body. Low pressure and high pressure fluid sources may be included. A first
fluid passage may connect the low pressure fluid source to the second chamber.
A second fluid passage may connect the high pressure fluid source to the second
chamber, and a third fluid passage may connect the high pressure fluid source to
the third chamber. A control valve may be connected to the low pressure fluid source,
to the high pressure fluid source, and to the first chamber. The control valve
may be configured to move between a first position at which the high pressure fluid
source is connected to the first chamber, and a second position at which the low
pressure fluid source is connected to the first chamber.
