Patent ID: 7685990

Claim:
A fuel injection apparatus for a fuel injector nozzle, the apparatus comprising: a nozzle body and a moveable valve needle slideably located within the nozzle body; wherein the nozzle body has a plurality of radial fuel outlets, at least one axial fuel outlet, an external surface, and an internal surface defining a valve seat positioned between a fuel supply path and the fuel outlets; wherein the valve needle comprises: a valve face that engages with the valve seat when the valve needle is in a seated position such that a fluid-tight seal is formed between the fuel supply path and the fuel outlets, an obturator piston that is engageable with the at least one axial fuel outlet, a spray shaping region having, at least in part, a concave, necked profile located between the valve seat and the obturator piston, wherein the profile of the valve needle transitions smoothly between the valve seat, spray shaping region, and obturator piston; and a two-stage lift mechanism for enabling lift of the valve needle; wherein each of the fuel outlets passes through the nozzle body from the internal surface to the external surface; wherein, in a first stage lifted position of the valve needle, the valve face is spaced apart from the valve seat, and the obturator piston is positioned such that a fuel flow passage is opened between the obturator piston and the axial fuel outlet; and wherein, in a second stage lifted position, the valve face is spaced further apart from the valve seat and the obturator piston is positioned such that the fuel flow passage between the obturator piston and the axial fuel outlet is substantially closed; wherein, in use, the profile of the spray shaping region encourages fuel passing the surface of the valve needle to be attached to it.