| 摘要 |
PROBLEM TO BE SOLVED: To improve braking precision of an exhaust valve when closing the valve in an exhaust valve device for a large-size slow-running two-stroke uniflow diesel engine.SOLUTION: An exhaust valve device comprises: an exhaust valve 1; a hydraulic actuator including a plunger 10', defining an actuation chamber 60 between a bore and the plunger 10', and carrying out an opening stroke when the actuation chamber is pressurized and a return stroke when the actuation chamber is connected to a tank; a hydraulic control valve 117, via which the actuation chamber 60 is selectively connectable to a source of high-pressure hydraulic fluid or to the tank; a hydraulic passageway 80, 85 connecting the actuation chamber 60 to the hydraulic control valve 117, and including a flow restriction that is active during the last part of an opening stroke and the first part of a return stroke of the exhaust valve 1; and a bypass device 117, 195, 197 for bypassing a flow restriction in the hydraulic passageway 80, 85 at least during the first part of the return stroke. |
