Claims:We Claim:
1. A fuel injector (10), said fuel injector (10) comprising:
- an injector body (12), said injector body (12) comprising a first end (12a) and a second end (12b);
- a nozzle (14) is located at said first end (12a) of said injector body (12);
- a fuel return line connecting means (16) located at said second end (12b) of said injector body (12), said fuel return line connecting means (16) is fitted into a drain socket (18) of said fuel injector (10);
characterized in that, said fuel return line connecting means (16) comprising:
- a back leak adapter (20), a first portion (20a) of said back leak adapter (20) fitted into said drain socket (18) and a second portion (20b) extends beyond said drain socket (18); and
- a banjo bolt (22) fitted into said back leak adapter (20).

2. A fuel injector (10) as claimed in claim 1, wherein said back leak adapter (20) comprises a recess (20c) and a flow path (20d) extending from said recess (20c) to one end of the back leak adapter (20).
3. A fuel injector (10) as claimed in claim 2, wherein said recess (20c) of said back leak adapter (20) has a threaded interface (20e).
4. A fuel injector (10) as claimed in claim 1, wherein diameter of said first portion (20a) of said back leak adapter (20) is smaller than the diameter of said second portion (20b) of said back leak adapter (20).
5. A fuel injector as claimed in claim 1 and 3, wherein said banjo bolt (22) is fitted into said recess (20c) of said back leak adapter (20) and interacts with said threaded interface (20e).
6. A fuel injector (10) as claimed in claim 1, wherein the outer surface of said second portion (20b) of said back leak adapter (20) has a first groove (20f) to accommodate a clamping saddle when said back leak adapter (20) is in the operational configuration of said fuel injector (10).
7. A fuel injector (10) as claimed in claim 1, wherein the outer surface of said second portion (20b) of back leak adapter (20) has a second groove (20g) to accommodate an O-ring (24).
8. A fuel injector (10) as claimed in claim 1, wherein the outer surface of said first portion (20a) of said back leak adapter (20) has a flat face.
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a fuel injector.

Background of the invention
[0002] In common rail system, the fuel injection system includes components such as a fuel tank, a fuel feed pump/pre-supply pump, a fuel filter, high-pressure pump, a common rail and an injector. These components are connected through the high pressure and the low-pressure circuits of the fuel injection systems. Fuel injection system components may be mounted on the engine cylinder head based on the availability of space. Fuel from the fuel tank is pumped by a pre-supply pump via a filter to the high pressure pump. The high pressure pump pressurizes the fuel and supplies to the common rail and to the injector through high-pressure pipes. Leakages from high pressure pump, common rail and the injectors are collected in the fuel return line and sent back to fuel tank. In case of injector leakages from internal components is collected via fuel return line and sent back to the fuel tank.

[0003] The injector is usually provided with a fuel return line connecting interface in the form of a back leak interface. The basic function of the back leak interface is to channel the fuel from the injector through the back leak interface and to the fuel return line. Different types of back leak interface implementations are known in the state of the art. One of the back leak interface implementation is a fast fit type connection between injector and the fuel return line. Another implementation is a banjo type connector. However the challenge of these different back leak interface implementation is that if the interface requirement for a specific implementation changes then the back leak interface has to be specially designed and customized. There is no one solution that can cater to every requirement. It is an objective of this disclosure to overcome the challenges of the back leak interfaces known in the state of the art.

Brief description of the accompanying drawings:
[0005] Different mode of the disclosure is disclosed in detail in the description and illustrated in the accompanying drawings:
[0006] Figure 1 illustrates a fuel injector in accordance with this disclosure;
[0007] Figure 2 illustrates an exploded view of the fuel injector in accordance with this disclosure; and
[0008] Figure 3 illustrates an exploded view of the fuel injector of figure 2 with specific focus on the fuel return line connecting means in accordance with this disclosure;
[0009] Figure 4a and figure 4b illustrates the back leak adapter in accordance with this disclosure.

Detailed description of the embodiments
[0010] Figure 1 illustrates a fuel injector 10 and Figure 2 illustrates an exploded view of the fuel injector 10 in accordance with this disclosure. The fuel injector 10 comprises an injector body 12. The injector body 12 comprises a first end 12a and a second end 12b. The fuel injector comprises a nozzle 14 located at the first end 12a of the injector body 12. The fuel injector 10 also comprises a fuel return line connecting means 16 located at the second end 12b of the injector body 12. The fuel return line connecting means 16 is fitted into a drain socket 18 of the fuel injector 10. The fuel injector 10 is characterized such that the fuel return line connecting means 16 comprises a back leak adapter 20. A first portion 20a of the back leak adapter 20 is fitted into the drain socket 18 and a second portion 20b extends beyond the drain socket 18 and a banjo bolt 22 fitted into the back leak adapter 20.

[0011] Additional constructional features of the fuel injector 10 will be explained with reference with figures 3, 4a and 4b. The back leak adapter 20 comprises a recess 20c and a flow path 20d extending from the recess 20c to one end of the back leak adapter 20. The recess 20c of the back leak adapter 20 has a threaded interface 20e. The back leak adapter 20 is such that the diameter of the first portion 20a of the back leak adapter 20 is smaller than the diameter of the second portion 20b of the back leak adapter 20. The banjo bolt 22 is fitted into the recess 20c of the back leak adapter 20 and interacts with the threaded interface 20e.

[0012] The back leak adapter 20 is such that the outer surface of the second portion 20b of the back leak adapter 20 has a first groove 20f to accommodate a clamping saddle when the back leak adapter 20 is in the operational configuration of the fuel injector 10. The back leak adapter 20 is such that the outer surface of the second portion 20b of the back leak adapter 20 has a second groove 20g to accommodate an O-ring 24. The back leak adapter is such that the outer surface of the first portion 20a of the back leak adapter 20 has a flat face 20h.

[0013] In the operative configuration of the fuel injector 10, the back leak adapter 20 is fitted into the drain socket 18 and the banjo bolt 22 is fitted into the back leak adapter. While the back leak adapter is fitted into the drain socket 18, the O-ring 24 creates an interference press fit to ensure that in the operative working configuration of the fuel injector 10 there will be no leakage of fuel. When the back leak adapter 20 is fitted to the drain socket, the clamping saddle ensures that no leakage occurs. The clamping saddle arrests both rotational and vertical movement of the back leak adapter 20. The threaded interface 20e that is provided in the recess 20c facilitates the assembly of the banjo bolt 22. In the operative configuration of the fuel injector 10 when the fuel injector 10 is fitted into the fuel injection system, a banjo connector (not shown in the drawings) will be fitted to the banjo bolt 22 and a fuel return line will be connected to the banjo connector. One end of the fuel return line is connected to the banjo connector and the other end of the fuel return line is connected to the fuel tank.

[0009] The working of the fuel injector 10 in the operative configuration is such that the leakage fuel from the components of the fuel injector 10 flows through the drain socket 18, then through the back leak adapter 20, through the banjo bolt 22, through the banjo connector, through the fuel return line and back to the fuel tank.

[0010] The advantage of using a fuel injector 10 with a fuel return line connecting means comprising a back leak connector 20 and a banjo bolt 22 is that, this provides a modular design. The modular design ensures injector function neutrality i.e. irrespective of the system requirement the modular design of the back leak connector 20 and the banjo bolt 22 can be used freely. This provides the advantage to the fuel injection system design engineers to adapt the back leak connector 20 to any application and any system requirements without comprising on the functionality of the fuel injector.

[0010] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims