| 摘要 |
Provided is a gas injection valve in which, when hydraulic oil pressure is applied to a liquid pressure chamber (51), an annular piston (43) and a piston extension (44) are caused to move up, and the outer peripheral face of the distal end portion of a needle valve (5) separates from the inner edge portion of an opening (3a) in a seat part (3). A spring bracket (45) and the needle valve (5) then undergo simple harmonic motion under the effect of the mass thereof and of the spring load of first and second springs (49, 50), and the needle valve (5) moves up and down. The cross-sectional area of a flow channel between the outer peripheral face of the distal end portion of the needle valve (5) and the inner edge portion of the opening (3a) increases and decreases in accordance with the up and down movement of the needle valve (5). As a result, the injection pressure of a fuel gas (G) fed into a cylinder through a gas injection channel (34) fluctuates when the fuel gas (G) is fed at a constant pressure to a gas supply channel (33). |
