Dynamic positioning device for an engine brake control

摘要

A device for use in an engine brake control to move an exhaust valve to an open position includes an actuator engageable with the exhaust valve and an electrically-operable control valve. The actuator includes a valve spool and a slave piston wherein the slave piston includes a passage and wherein the valve spool includes a high pressure annulus coupled to a source of high fluid pressure and a low pressure annulus coupled to a source of low fluid pressure. The valve spool is movable relative to the slave piston to interconnect the passage with the high pressure annulus or the low pressure annulus. The electrically- operable control valve selectively provides high fluid pressure to the valve spool and to the slave piston to cause the slave piston to oscillate about a point at which the exhaust valve is disposed in the open position and the passage is alternately connected to the low pressure annulus and the high pressure annulus.