| 摘要 |
In this gas injection valve, when operating hydraulic pressure is applied to a hydraulic chamber (51), a toroidal piston (43) and a piston extension portion (44) rise upwards, and an outer circumferential surface of a distal end portion of a needle valve (5) moves away from an inside edge portion of an aperture (3a) of a seat portion (3). A spring bearing (45) and the needle valve (5) are affected by their own mass and by the spring loading of first and second springs (49 and 50) so that they perform a simple harmonic oscillation, and cause the needle valve 5 to move up and down. The area of the flow path between the outer circumferential surface of the distal end portion of the needle valve (5) and the aperture (3a) of the seat portion (3) increases and decreases in accordance with the rising and falling of the needle valve (5). Accordingly, even if fuel gas (G) is fed at a constant pressure to a gas supply path (33), the injection pressure of the fuel gas (G) that is supplied via a gas injection path (34) to the interior of a cylinder liner can be varied. |
