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A fuel injector device having a blowback valve disposed in the injector body, the blowback valve having a first portion and a second portion, a fuel passage being disposed through the first and second portions, a closure member being disposed in the fuel passage and movable in a first direction and

A fuel injector device having a blowback valve disposed in the injector body, the blowback valve having a first portion and a second portion, a fuel passage being disposed through the first and second portions, a closure member being disposed in the fuel passage and movable in a first direction and a second direction, the closure member permitting a predetermined volume of fuel flow in the second direction before the closure member moves to the second position. The invention also include a method to control the fuel flow through an injector by providing a body having a first portion and a second portion, a fuel passage extending through the portions and a closure member movable in the fuel passage between a first position and a second position, and the closure member permitting a predetermined volume of fuel to flow in one direction before the closure member moves to the second position. The predetermined volume of fuel is related to the displacement of the closure member of the blowback valve and the displacement of the needle assembly of the fuel injector between an injecting position and a non-injecting position.

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1. An injector for metering fuel into a combustion chamber, the injector comprising:a body having a first portion and a second portion;a chamber formed along the axis of the injector, the chamber confronting the first portion and coupled to the fuel passage;a plunger reciprocally movable in the cham

1. An injector for metering fuel into a combustion chamber, the injector comprising:a body having a first portion and a second portion;a chamber formed along the axis of the injector, the chamber confronting the first portion and coupled to the fuel passage;a plunger reciprocally movable in the chamber;a fuel passage extending through the body, the fuel passage having a first segment extending through the first portion and a second segment extending through the second portion;a closure member movable in the fuel passage between a first position which exposes a flow area which is at least equal to a diameter of the fuel passage to avert throttling in the fuel passage between the first segment and the second segment, and a second position, the first position permitting fuel flow in a first direction through the fuel passage, the closure member permitting a predetermined volume of fuel flow in a second direction, oposite the first direction, before the closure member moves to the second position and prohibits fuel flow in the second direction, the chamber being fluid communication with the fuel passage; anda needle assembly in fluid communication with the fuel passage and movable between a first position and a second position, the predetermined volume of fuel relating at least to the displacement of the needle assembly between the first position and the second position of the needle assembly. 2. The injector as claimed in claim 1, wherein the second segment includes first part having a first cross-sectional size and a second part having a second cross-sectional size larger than the first cross-sectional size, and wherein the closure member is movable in the second part. 3. The injector as claimed in claim 2, wherein the fuel passage has a substantially constant cross-sectional size. 4. The injector as claimed in claim 3, wherein a cross sectional flow area between the closure member and the second part is at least equal to the cross sectional size of the fuel passage. 5. The injector as claimed in claim 1, wherein the predetermined volume of fuel flow is related to the product of the distance of the movement of the closure member and the cross-sectional area of the second part. 6. The injector as claimed in claim 1, wherein the closure member comprises a disc having a first surface substantially parallel to a second surface. 7. The injector as claimed in claim 6, a plane parallel to the axis of the disc and intersecting the disc defines the first surface and another plane parallel to the disc and intersecting the disc defines the second surface. 8. The injector as claimed in claim 1, wherein the closure member comprises a sphere having a radius of curvature. 9. The injector as claimed in claim 8, wherein the second portion comprises a seat. 10. The injector as claimed in claim 9, wherein the seat comprises a portion of a sphere having a radius of curvature substantially equal to the radius of curvature of the sphere. 11. The injector as claimed in claim 9, wherein the seat is adapted to be filled with fuel and the closure member is adapted to displace the fuel in the seat. 12. The injector as claimed in claim 1, wherein the first segment is oriented obliquely with respect to the second segment. 13. The injector as claimed in claim 1, wherein the closure member comprises a disc having a first surface substantially parallel to a second surface thereby creating a gap between the first surface and the second surface and a wall of the second segment of the fuel passage. 14. The injector as claimed in claim 1, wherein a volume of fluid to flow back is determined by the first segment having a first diameter and a distance of travel of the closure member to a sealing surface of the first segment. 15. An injector for metering fuel into a combustion chamber, the injector comprising:a body having a first portion and a second portion: a chamber formed along the axis of the injector, the chamber confronting the first portion and coupled to t he fuel passage, the second portion comprises a seat and an annular groove surrounding the seat;a plunger reciprocally movable in the chamber;a fuel passage extending through the body, the fuel passage having a first segment extending through the first portion and a second segment extending through the second portion, the annular groove being a part of the second segment;a closure member movable in the fuel passage between a first position and a second position, the first position permitting fuel flow in a first direction through the fuel passage, the second position prohibiting fuel flow in a second direction opposite to the first direction, the closure member comprises a sphere having a radius of curvature and further permitting a predetermined volume of fuel flow in the second direction before the closure member moves to the second position, the chamber being fluid communication with the fuel passage; anda needle assembly in fluid communication with the fuel passage and movable between a first position and a second position, the predetermined volume of fuel relating at least to the displacement of the needle assembly between the first position and the second position of the needle assembly. 16. An injector for metering fuel into a combustion chamber, the injector comprising:a body having a first portion and a second portion: a chamber formed along the axis of the injector, the chamber confronting the first portion and coupled to the fuel passage;a plunger reciprocally movable in the chamber;a fuel passage extending through the body, the fuel passage having a first segment extending through the first portion and a second segment extending through the second portion, the first segment being axially offset with respect to the second segment;a closure member movable in the fuel passage between a first position and a second position, the first position permitting fuel flow in a first direction through the fuel passage, the second position prohibiting fuel flow in a second direction opposite to the first direction, the closure member permitting a predetermined volume of fuel flow in the second direction before the closure member moves to the second position, the chamber being fluid communication with the fuel passage; anda needle assembly in fluid communication with the fuel passage and movable between a first position and a second position, the predetermined volume of fuel relating at least to the displacement of the needle assembly between the first position and the second position of the needle assembly. 17. The injector as claimed in claim 16, wherein a shallow bore is formed in the second segment, the cross-sectional area of the shallow bore overlapping the cross sectional area of the annular groove. 18. The injector as claimed in claim 17, wherein the area defined by the overlapping cross-sectional areas is at least equal to the cross-sectional area of the fuel passage. 19. A method of controlling fuel flow through an injector for an internal combustion engine, the method comprising:providing a body having a first portion and a second portion, a fuel passage extending through the body, the fuel passage having a first segment extending through the first portion and a second segment extending through the second portion, a closure member movably in the fuel passage between a first position and a second position, the closure member, when in the first position, creating a flow area at least equal to a diameter of the fuel passage to avert a throttling effect in the first segment and the second segment of the fuel passage, a needle assembly in fluid communication with the fuel passage and movable between non-injecting position and a fluid injecting position;permitting fuel flow in a first direction through the closure member and the fuel passage;prohibiting fuel flow in a second direction opposite to the first direction;causing the needle assembly to move to a fluid-injecting position;permitting the needle assembly to move to a n on-injecting position; andpermitting a predetermined volume of fuel flow in the second direction before the closure member moves to the second position. 20. The method as claimed in claim 19, wherein the second segment includes first part having a first cross-sectional size and a second part having a second cross-sectional size larger than the first cross-sectional size, and wherein the closure member is movable in the second part. 21. The method as claimed in claim 20, wherein the predetermined volume of fuel flow is defined by the product of the distance traveled by the closure member between the first and second position and the cross-sectional area of the second part. 22. The method as claimed in claim 20, wherein the predetermined volume of fuel flow is related to the displacement of the needle assembly movable between the non-injecting position and the fluid injecting position.