Injector seat that includes a coined seal band with radius
A fuel injector apparatus and method is provided for use in a fuel injection system of an internal combustion engine that includes a body, a valve seat, closure member, and an orifice plate. The valve seat comprises the intersection of two angled surfaces with a radius before assembly of the fuel injector. During assembly of the fuel injector, a member presses against the radius edge of the sealing surface of the valve seat to create an oblique third sealing surface or sealing band that is coined into the valve seat. The sealing band provides an improved seal between the valve closure member and the valve seat which operates to prevent leakages of fuel in the fuel injector.
1. A fuel injector for an internal combustion engine, comprising:
a body having an inlet, an outlet and a longitudinal axis entering therethrough;
a valve assembly regulating the flow of fuel to a combustion chamber wherein a closure member rests on a valve seat in a closed position to prohibit the flow of fuel, the valve seat having an upstream surface meeting a downstream surface to form a radius edge;
a sealing band coined into the radius edge, deforming the radius edge and thereby defining a concave oblique third contact surface of the valve seat, upon the axial movement downwards of an assembly member onto a sealing surface of the valve seat, the oblique third contact 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 oblique third contact surface in the closed position; and
an orifice disk having at least one orifice for allowing fuel to pass from the valve assembly to the combustion chamber when the closure member is biased into an open position;
wherein, prior to the formation of the sealing band, the upstream surface has an included angle that is greater than an included angle of the downstream surface thereby defining an included angle of the radius edge, and wherein the included angle of the radius edge is bisected by a line through a contact point of the closure member with the radius edge, and the center of the closure member.
2. The fuel injector of claim 1 , wherein the radius edge is convex in shape.
3. The fuel injector of claim 1 , wherein a radius of the radius edge ranges from 0.005 mm to 0.150 mm.
4. The fuel injector of claim 1 , wherein the upstream surface has a range of included angles from 120° to 135° prior to assembly of the fuel injector.
5. The fuel injector of claim 1 , wherein the downstream surface has a range of included angles from 90° to 105° prior to assembly of the fuel injector.
6. The fuel injector of claim 1 , wherein the upstream surface included angle is greater than the downstream surface included angle.
7. The fuel injector of claim 1 , wherein the sealing band further comprises a tangential relationship to a downstream end of the valve closure member.
8. The fuel injector of claim 1 , wherein the sealing band width ranges from 0.05 mm to 0.20 mm.
9. The fuel injector of claim 1 , wherein the closure member is shaped as a sphere or a truncated sphere.