Method and apparatus for defining a spray pattern from a fuel injector

A method and apparatus for defining a spray pattern to reduce the variation in the metering, targeting, distribution, and atomization of the fuel output of a fuel injector. The fuel injector contains a closure member (12) extending along the longitudinal axis of the injector. The closure member (12) can be positioned contiguous to a seat to occlude fuel flow. A sealing radius (18) is defined when the closure member is in this position. The closure member can also be positioned such that it is not contiguous to the seat, thereby permitting fuel flow. A plate (200) is disposed proximate to the seat with a first (202) and second face (204), the first face (202) facing the seat. An inlet (206) is located on the first face (202) of the plate (200), and at least one chamber (208) is disposed on the second face (204) of the plate (200). The inlet (206) and the at least one chamber (208) are in fluid communication. An orifice disc (300) is disposed in a confronting arrangement with the second face (204) of the plate (200) such that each chamber (208) is located proximal to each orifice. The orifice disc (300) is positioned such that its axis is generally coincident with the longitudinal axis of the fuel injector. At least one orifice is located at a second radius (302) from the axis of the orifice disc (300), wherein the second radius (302) is greater than the sealing radius (18).