EQUILIBRIUM POSITION VALVE SPINDLE

摘要

PROBLEM TO BE SOLVED: To provide a gas exchange valve having a braking performance which decelerates a valve spindle of an exhaust valve on the final stage during a valve opening process, in a cross-head type large 2-stroke uniflow diesel engine.SOLUTION: An exhaust valve for a cross-head type 2-stroke uniflow diesel engine includes: a spindle bore 5; a valve spindle 10; a valve actuator 109; a center bore which forms an upper part of the spindle bore 5; an upper part 14 of the spindle 10 which is received in the center bore 6 and can be translated in a direction of a longitudinal axis A; a middle part 66 of the bore 6; a variable volume valve actuation chamber 60 for opening the exhaust valve 1; and hydraulic oil passage connecting the variable volume valve actuation chamber 60 to a pressurizing hydraulic oil source, wherein at least one axial elongated slit 19 is formed on a lower end of the upper part 14 of the spindle 10 and the slit 19 gradually decreases a flow of the pressurizing hydraulic oil to the variable volume valve actuation chamber 60 from the pressurizing hydraulic oil source as the upper part 14 passes through the middle part 66.