Patent ID: 7530508

Claim:
A fuel injection valve comprising: a valve seat member which includes: a conical valve seat; and a valve hole penetrating a central portion of the valve seat; a valve element for opening and closing the valve hole in cooperation with the valve seat; an injector plate which has a plurality of fuel injection holes arranged so as to be displaced radially outward of the valve hole and which is joined to the valve seat member; and a diffusion chamber provided between the valve seat member and the injector plate so as to provide a communication between the valve hole and the fuel injection holes, wherein a fuel guide member facing the valve hole is connected to a central portion of the injector plate; the annular diffusion chamber has a diameter larger than that of the valve hole and is formed between the valve seat member and the injector plate, inner ends of the fuel injection holes being opened in the annular diffusion chamber, an outer peripheral surface of the fuel guide member facing the annular diffusion chamber; a pair of first notches, a pair of second notches, and a plurality of closing parts are formed in an outer periphery of the fuel guide member, the first notches having large notch areas and being opened in directions opposite from each other to provide a communication between the valve hole and the diffusion chamber, the second notches having small notch areas and being opened in directions opposite from each other on a diameter line passing between the pair of first notches to provide a communication between the valve hole and the diffusion chamber, the closing parts being provided between the first and second notches to partially close the valve hole; the plurality of fuel injection holes are divided into two groups arranged on opposite sides of the diameter line, and the plurality of fuel injection holes of each group are dispersally arranged in outside regions corresponding to the closing parts and an inside region corresponding to the first notch; a first tip end corner of the closing part adjacent to the first notch is formed into an edge shape or a minute arc shape, and a second tip end corner of the closing part adjacent to the second notch is formed into a large arc shape having a curvature smaller than that of the first tip end corner.