Claims:We Claim:
1. A fuel injector, said fuel injector (100) comprising at least:
- an injector body (105),
- a nozzle body (110) abutting one end of said injector body (105) when said fuel injector (100) is held in assembly position,
- a nozzle needle (145) enclosed in said nozzle body (110), characterized in that:

- a hollow feed tube (200) inserted in said nozzle needle (145).

2. The fuel injector as claimed in claim 1, wherein said hollow feed tube (200) does not wholly encompass the radius of said nozzle needle (145).
3. The fuel injector as claimed in claim 1, wherein said hollow feed tube (200) can be rotated radially around the axis of said nozzle needle (145).
4. The fuel injector as claimed in claim 1, wherein said hollow feed tube (200) covers the entire length of said nozzle needle (145).

5. A fuel injection system, said fuel injection system comprising at least:

- a fuel injector (100), said fuel injector (100) comprising at least:
- an injector body (105)
- a nozzle body (110) abutting one end of said injector body (105) when said fuel injector (100) is held in assembly position
- a nozzle needle (145) enclosed in said nozzle body (110), characterized in that:
- a hollow feed tube (200) inserted in said nozzle needle (145).
6. The fuel injection system as claimed in claim 6, wherein said hollow feed tube (200) does not wholly encompass the radius of said nozzle needle (145).
7. The fuel injection system as claimed in claim 6, wherein said hollow feed tube (200) can be rotated radially around the axis of said nozzle needle (145).
8. The fuel injection system as claimed in claim 1, wherein said hollow feed tube (200) covers the entire length of said nozzle needle (145).
, 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] The present disclosure relates generally to common rail fuel injectors, and more particularly to a hollow tube inside the nozzle of common rail fuel injectors.

Background of the invention
[0002] In engine project with higher inclination of injector in cylinder head, spray holes in the direction of inclination will have higher elevation angle compared to other spray holes, due to their higher elevation angle hydro erosion rounding will be low in those spray holes compared to the other spray holes with lower elevation angles, this causes non uniform hydro erosion rounding of spray hole inlet edges, i.e typically holes with higher elevation angle will have poor rounding of the edges compared to holes with lower elevation angle, this intern cause variation in coefficient of discharge (cd) among spray holes , that is ,lower cd in spray holes with higher elevation angle, hence spray performance will not be uniform among all spray holes in nozzle.
[0003] The idea is related to the functional improvement of an existing product by a design feature; the challenge of non-perpendicular and eccentrical mounted injectors is not only the wall hitting of the sprays with the smaller distance to the bowl wall it is the lesser spray momentum by the higher deflection (bigger elevation angle) of appropriate nozzle hole bore.
[0004] To overcome with the existing issue of poor spray development, it is necessary to correct or to modify the some of the design parameters.

Brief description of the accompanying drawings
[0005] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0006] Figure 1 illustrates a common rail fuel injector in accordance with an embodiment of our invention.
[0007] Detailed description of the drawings
[0008] Figure 1 illustrates a common rail fuel injector (100). The common rail fuel injector (100) comprises among other things at least an injector body (105), a nozzle body (110) that abuts from one end of the injector body 9105) when the fuel injector (100) is held in assembly position and a nozzle hole (115) which opens up to the nozzle needle (140) of the fuel injector (100). The nozzle needle (140) ends up to a nozzle needle tip (145). Leading to the nozzle needle tip (145) is a sac (135). The sac (135) of the fuel injector (100) has a plurality of spray holes (130a) radially disposed around it. One end of the spray holes (130) open up to the sac (135), while a second end opens up to a combustion chamber (125).

[0009] In one embodiment of the common rail fuel injector (100), a hollow feed tube is inserted into the nozzle needle (145) of said common rail fuel injector (100). The hollow feed tube (200) is radially disposed across the nozzle needle (145) but does not completely cover the entire radius. The main idea is that the hollow feed tube (200), which also covers the plurality of spray holes (130a) of the common rail fuel injector (100), is rotatable.
[0010] This hollow feed tube (200) can rotate/indexed to round the other spray holes one after another. By varying the erosion timing for individual or set of holes, more uniform rounding can be achieved among spray holes (130a), this enables to achieve uniform coefficient of discharge in nozzle spray holes(130a) to have uniform spray performance among spray holes
[0011] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the common rail fuel injector (100) are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.