| 摘要 |
PROBLEM TO BE SOLVED: To increase valve opening speed, enlarge a device, and reduce fuel consumption ratio by simultaneously moving an outer piston and an inner piston for an initial fixed period at opening of an exhaust valve through pressure of operating oil, and moving only the inner piston after the outer piston is stopped by a stopper part. SOLUTION: At initial opening of an exhaust valve 2, an operating oil pressure P is acted on both of outer and inner pistons 31, 32 until a stopper part 31a of the outer piston 31 collides with a step difference part 33a of a hydraulic cylinder 33. A force for pushing the exhaust valve 2 in a valve opening direction is set to F1=(π/4)(D12×P), and then the force for pushing the exhaust valve 2 by the operating oil pressure P after movement of the outer piston 31 is stopped, becomes F2=(π/4)(D22×P). Here, D1 represents the outer diameter of the outer piston 31, and D2 represents the outer diameter of the inner piston 32. At the initial period of valve opening, relation between F1 and F2 is F1>F2, the valve opening speed is accelerated, and work is increased, whereas after a middle stage where the exhaust gas energy is small, only inner piston 32 having small outer diameter D2 is acted to suppress operating oil consumption.
|
