Patent ID: 8307550

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 sealing edge, the upstream surface having an included angle that is greater than an included angle of the downstream surface thereby defining an included angle of the sealing edge, the included angle of the sealing edge having a vertex defining a contact point of a closure member with the sealing edge, the vertex being arranged such that a line passes through the vertex, bisecting the included angle into two equal parts, and passes through the center of the closure member; coining the sealing surface of the valve seat to create a sealing band surface onto the sealing edge by deforming a portion of the sealing edge including the vertex; and displacing the closure member axially downwards onto the sealing band surface of the valve seat to seal the valve seat.