Patent ID: 7434752
Filing Date: 2008-10-14
Classification: F02M,Y10S

Abstract:
1. A fuel injection valve comprising a valve assembly having a valve portion; a valve seat member having provided therein a conical valve seat and a valve seat hole, the valve seat cooperating with the valve portion, and the valve seat hole communicating with a downstream end of the valve seat; an injector plate, the injector plate being joined to the valve seat member; a radially extending and annular fuel diffusion clamber, the fuel diffusion chamber being formed between the valve seat member and the injector plate, and a downstream end of the valve seat hole opening in a central part of the fuel diffusion chamber; and a plurality of fuel injection holes, the fuel injection holes being bored in tie injector plate so as to be radially outwardly separated from the valve seat hole and open to an inside of the fuel diffusion chamber; wherein an annular depression is formed in the valve seat member between the downstream end of the valve seat and an upstream end of the valve seat hole so as to provide a connection therebetween, a fuel collecting chamber is defined by the depression and a front end face of the valve portion of the valve assembly, and the fuel collecting chamber has a base of conical shape, wherein the valve seat hole is formed such that, when the height of the fuel diffusion chamber is t wherein an annular corner is formed to connect between the base of the fuel collecting chamber and an inner peripheral face of the valve seat hole, said annular corner having a tapered or arc-shaped chamfer, and wherein the fuel diffusion chamber is defined by an annular depression formed in a front end face of the valve seat member such that the height of a section of the fuel diffusion chamber that the fuel injection holes face is 20 to 110 μm to make the fuel diffusion chamber flat and thin relative to the length of the valve seat hole so that the flow of fuel spreads radially at high speed in film form in the fuel diffusion chamber and is detached from an inner peripheral wall of the fuel injection holes.