Patent ID: 8261446

Claim:
A method of lowering leakage rates in a fuel injector, the fuel injector having a body having an inlet, an outlet and a longitudinal axis; a valve assembly regulating the flow of fuel wherein a closure member rests on a valve seat in a closed position that prohibits the flow of fuel; an orifice disk having at least one orifice for allowing fuel to pass from valve assembly when closure member is biased into an open position, the method comprising: providing a sealing surface of the valve seat having an upstream surface meeting a downstream surface to form a radius edge; and after the providing step, coining the sealing surface of the valve seat to create a concave sealing band surface onto the radius edge with the concave sealing band surface being coin fitted with an outer convex surface of the closure member so that a portion of the outer convex surface of the closure member conforms in a complementary mating manner with and engages the concave sealing band surface in the closed position, wherein an included angle of the upstream surface is greater than an included angle of the downstream surface thereby defining an included angle of the radius edge, the included angle of the radius edge being bisected by a line passing through a contact point of a closure member with the radius edge, and the center of the closure member, thereby bisecting the included angle of the radius edge into two equal angles.