Field of the invention
[0001] This invention relates to a back leak connector and more specifically to a back
leak connector for a fuel injector.
Background of the invention
[0002] US Patent Publication Number 2010282211 A describes a fuel delivery system. The fuel delivery system for an internal combustion engine comprises at least one fuel injector, the fuel injector comprising a control chamber having an inlet for receiving highly pressurized fuel and an outlet enabling fuel to flow out of the control chamber into a back-leak passage associated with the fuel injector, wherein the fuel injector is operable between an injecting state and a non-injecting state in dependence on the fuel pressure within the control chamber. The system further includes a pressure regulator for regulating the fuel pressure within the back-leak passage so as to maintain the injector back-leak pressure at a predetermined target value which is below atmospheric pressure.
Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic diagram of a back leak connector for a fuel
injector.
Detailed description of the embodiments
[0004] Figure 1 illustrates a schematic diagram of a back leak connector 10 for a fuel injector. The back leak connector 10 comprises a fuel injector body 12 comprising a U-shaped cavity 14 and a notched portion 16 defined in the U-shaped cavity 14. The notched portion 16 has a first diameter at its top portion 18 and a second diameter at its bottom portion 20, wherein the second diameter is greater than the first diameter. A connector 22 comprises an inner sidewall and an outer sidewall, wherein the connector 22 is inserted within the U-shaped cavity 14 such that a bottom portion of

the connector 22 is flush against a bottom surface of the U-shaped cavity 14, and wherein the inner sidewall of the connector is flush against the notched portion 20 that is defined in the U-shaped cavity 14.
[0005] The back leak connector 10 for a fuel injector comprises a fuel injector body 12 comprising a U-shaped cavity 14 and a notched portion 20 defined in the U-shaped cavity 14. The U-shaped cavity 14 comprises a base portion that is at a lower level than the notched portion 20 and is defined on either side of the notched portion 20. The notched portion 20 defined in the U-shaped cavity 14 has a first diameter at its top portion 18, a second diameter at its bottom portion 20, and a tapering surface extending from the top portion 18 to the bottom portion 20. In the exemplary embodiment, the second diameter is greater than the first diameter. The notched portion 16 is defined midway between the U-shaped cavity 14 and is adapted to receive a connector 22 therein.
[0006] The connector 22 comprises an inner sidewall and an outer sidewall. The connector 22 is inserted within the U-shaped cavity 14 such that a bottom portion of the connector 22 is flush against a bottom surface of the U-shaped cavity 14. Moreover, the inner sidewall of the connector 22 is flush against the notched portion 20 that is defined in the U-shaped cavity 14. Therefore, there exists a minimum clearance between the connector 22 and the fuel injector body 12 that facilitates the fuel that flows through the injector from flowing past the interface between the connector 22 and the fuel injector body 12. In the exemplary embodiment, a fuel passage exists between the top portion of the connector 22 and the bottom portion of the connector 22 and channels fuel from the top portion of the connector 22 to the bottom portion of the connector 22. Moreover, a fuel passage 32 exists that extends from the notched portion 16 of the injector body and out of the body of the fuel injector. Therefore, the fuel that flows into the top portion of the connector 22 flows

out of the fuel injector from the fuel passage 32 that extends from the notched portion 16 of the body of the fuel injector.
[0007] The connector 22 comprises a first notched portion 24 and a second notched portion 26 that are defined at the bottom portion of the connector 22 and a recess 28 defined between the first notched portion 24 and the second notched portion 26 respectively. The first notched portion 24 and the second notched portion 26 of the connector 22 are adapted to compress such that the bottom portion of the connector 22 is flush against the bottom surface of the U-shaped cavity 14 to facilitate gripping the connector 22 between the U-shaped cavity 14 and the notched portion 16 that is defined in the U-shaped cavity 14. More specifically, the connector 22 is manufactured from a ductile and deformable material such as mild steel while the fuel injector body 12 is manufactured from a hard and non-deformable material such as cast iron. The first notched portion 24 and the second notched portion 26 of the connector 22 are adapted to compress when the connector 22 is pressed down against the fuel injector body 12. The bottom portion of the connector 22 is flush against the bottom surface of the U-shaped cavity 14. Therefore, since the first notched portion 24 and the second notched portion 26 of the connector 22 are adapted to compress when the connector 22 is pressed down against the fuel injector body 12, the connector 22 is lodged firmly between the fuel injector body 12 and the notched portion 16 of the fuel injector body 12.
[0008] In the exemplary embodiment, the connector 22 comprises a plurality of spirally shaped grooves 30 that are defined on its outer circumference. In the exemplary embodiment, the plurality of spirally shaped grooves 30 are inclined with respect to the horizontal axis. If the fuel flows through the spirally shaped grooves 30 from one end and comes out of the spirally shaped grooves 30 from the other end, the fuel can flow out of the fuel injector body 12 and cause wetting on the sidewall of the

fuel injector. However, the inclination of the plurality of grooves 30 that are defined on the outer circumference of the connector 22 causes a resistance to the flow of fuel along the plurality of grooves 30 and out of the fuel injector body 12, and cause wetting on the sidewall of the fuel injector. More specifically, the inclination of the plurality of grooves 30 makes it more difficult to overcome the forces of gravity and rise upwardly out of the plurality of grooves 30 and out of the fuel injector body 12 and thereby cause wetting on the sidewall of the fuel injector.
[0009] The assembly of the back leak connector 10 for the fuel injector is described as an example. When the connector 22 is pressed down within the U-shaped portion 14, the connector 22 circumscribes the notched portion 16 of the fuel injector body 12. Due to the tapering surface of the notched portion 16 of the fuel injector body 12, the flat shaped connector 22 is wedged in between the notched portion 16 of the fuel injector body 12 and the inner sidewall of the fuel injector body 12. When the connector 22 is pressed down within the fuel injector body 12, the first notched portion 24 and the second notched portion 26 of the connector 22 are adapted to be compressed. Thereby, the connector 22 is lodged firmly between the fuel injector body 12 and the notched portion 16 of the fuel injector body 12. The first notched portion 24 and the second notched portion 26 of the connector 22 are adapted to compress, thereby causing the first notched portion 24 and the second notched portion 26 of the connector 22 to be flush against the bottom surface of the body of the U-shaped cavity 14. This prevents the connector 22 from being withdrawn from the U-shaped cavity 14 of the fuel injector body 12.
[0010] As a small quantity of fuel flows through the gap between the connector 22 and the fuel injector body 12, it rises along the gap that is defined between the connector 22 and the fuel injector body. Due to the inclination of the plurality of grooves 30 that are defined on the connector 22, the fuel that flows through the gap between the

connector 22 and the fuel injector body 12 cannot rise due to the resistance offered against the flow of fuel by the plurality of grooves 30 that are defined on the connector 22 by virtue of the inclination of the plurality of grooves 30 that are defined on the connector 22. Consequently, the fuel is retained within the fuel injector body 12, and the fuel is only permitted to flow from the connector 22 to the fuel injector body 12 via the bore 32 that is defined on the connector 22 and the bore 40 that is defined in the notched portion 16 of the fuel injector.
[0011] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.

1. A back leak connector (10) for a fuel injector, said back leak connector (10)
comprising:
a fuel injector body (12) comprising a U-shaped cavity (14) and a notched portion (16) defined in the U-shaped cavity (14), said notched portion (16) having a first diameter at its top portion (18) and a second diameter at its bottom portion (20), the second diameter greater than the first diameter; and a connector (22) comprising an inner sidewall and an outer sidewall, said connector (22) inserted within the U-shaped cavity (14) such that a bottom portion of said connector (22) is flush against a bottom surface of the U-shaped cavity (14), and wherein the inner sidewall of the connector (22) is flush against the notched portion (20) that is defined in the U-shaped cavity (14).
2. The back leak connector (10) for a fuel injector in accordance with Claim 1
wherein said connector (22) comprises a first notched portion (24) and a second
notched portion (26) that are defined at the bottom portion of said connector
(22) and a recess (28) defined between the first notched portion (24) and the
second notched portion (26), wherein the first notched portion (24) and the
second notched portion (26) of said connector (22) are adapted to compress
such that the bottom portion of said connector (22) is flush against the bottom
surface of the U-shaped cavity (14) to facilitate gripping said connector (22)
between the U-shaped cavity (14) and the notched portion (20) that is defined
in the U-shaped cavity (14).

3. The back leak connector (10) for a fuel injector in accordance with Claim 1 wherein said connector (22) comprises a plurality of grooves (30) that are defined on its outer circumference, wherein the inclination of the plurality of grooves (30) that are defined on the outer circumference of said connector (22) causes a resistance to the flow of fuel along the plurality of grooves (30) and out of the connector (22).