| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust valve drive device which is a cam hydraulic oil drive system capable of flexibly regulating the operation of an exhaust valve in accordance with the operation state of an internal combustion engine.SOLUTION: An exhaust valve drive device 1 is provided in which a piston 7 is actuated by hydraulic fluid pressurized by a plunger 11 so as to open an exhaust valve 5 while the piston 7 is actuated by decompressing the pressurized hydraulic fluid by the plunger 11 so as to close the exhaust valve 5. The exhaust valve drive device 1 comprises: a branch passage 40 with one end connected to a hydraulic passage 9 between the piston 7 and the plunger 11; an on-off valve 42 provided along the branch passage 40; an additional volume part 44 to which the other end of the branch passage 40 is connected as well as accommodating the hydraulic fluid; and a control part controlling the on-off valve 42, in which the control part closes the on-off valve 42 while the hydraulic fluid being pressurized by the plunger 11 and opens the on-off valve 42 from the closed state prior to decompressing the hydraulic fluid which is pressurized by the plunger 11.SELECTED DRAWING: Figure 1 |
