Claims:We claim:
1. A nozzle (20) for a fuel injector (10), said nozzle (20) comprising at least a needle (102), a nozzle body (104), a nozzle guide region (108) and a needle guide region (110);
- Characterized in that a guide ring (112) configured to be at the operative top of the nozzle guide region (108) where said guide ring (112) is partially in contact with the needle guide region (110).
2. The nozzle (20) as claimed in claim 1, wherein the guide ring (112) has a semicircular cross section.
3. The nozzle (20) as claimed in claim 1, wherein the guide ring (112) is placed in a recess (114) in the nozzle body (104), said recess (114) located at the operative top of the nozzle guide region (108).
4. A fuel injector (10), said fuel injector (10) comprising at least:
- an injector body (106);
- a nozzle (20), said nozzle (20) comprising at least a nozzle body (104), a needle (102), a nozzle guide region (108) and a needle guide region(110); and
- a guide ring (112).
5. The fuel injector (10) as claimed in claim 4, wherein the guide ring (112) is located in a recess (114) in the nozzle body (104), said recess (114) located at the operative top of the nozzle guide region (108).
, Description:Complete specification: The following specification particularly describes the invention and the manner in which it is to be performed. 
Field of the invention:
[0001] This invention relates to a fuel injector and particularly relates to the nozzle of the fuel injector.

Background of the Invention:
[0002] A person skilled in art would be aware that many version of fuel injectors are already known. However, some basic components in a fuel injector are always present. Following are some of the basic components of any fuel injector known in the state of the art viz the injector body components, the magnet group components, electrical connector components, nozzle module components and the like. With regard to this disclosure we will specifically focus on the nozzle module components, especially the nozzle and the needle. The nozzle module components mainly comprise of two main components, namely the nozzle body and the nozzle along with their respective guide regions, namely nozzle guide region and needle guide region.
[0003] The nozzle module components are in aligned engagement with the injector body components. Moreover, the needle and the nozzle guide region are in constant contact. In the existing scenario, this contact of needle to the nozzle guide region leads to a one sided wear inside the nozzle guide region which results in rubbing marks at the nozzle guide region. The wear caused due to the rubbing ultimately lead to an increase in the fuel back leak quantity.
[0004] Any fuel injector experiencing an increased quantity of fuel back leak has a plurality of disadvantages thereby decreasing the performance of the engine as well as the performance of the vehicle itself. The increase back flow can lead to an increase in the back pressure in the cumulative return line, and in turn affecting the performance of the high pressure pump. In addition to this, the nozzle guide wear will lead to an increase in fuel back leak quantity and back pressure and thereby contributing to an increase in the fuel tank temperature. Moreover, in some pumps, the high back leak may lead to chances of fuel being sucked from return line and unnecessary pressure being build up due to this high back leak.
[0005] Therefore, there exists a need for a solution to prevent direct contact of needle with nozzle guide region and thereby reduce the wear of the nozzle guide region, as described in this disclosure.

Brief Description of Drawings:
[0006] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0007] Fig. 1 illustrates a fuel injector according to an embodiment of the present invention;
[0008] Fig. 2 illustrates a nozzle for a fuel injector according to an embodiment of the present invention; and
[0009] Fig. 3 illustrates the nozzle-needle guide regions of a nozzle of a fuel injector according to an embodiment of the present invention.

Detailed description of the embodiments:
[0010] Fig 1 illustrates a fuel injector (10), according to an embodiment of the present invention. The fuel injector (10) an injector body (106) and a nozzle (20). Moreover, said nozzle (20) comprising at least a nozzle body (104), a needle (102), a nozzle guide region (108) and a needle guide region(110).
[0011] Fig. 2 illustrates the nozzle (20) for a fuel injector according to an embodiment of the present invention.
[0012] Fig. 3 illustrates the nozzle-needle guide regions of a nozzle of a fuel injector according to an embodiment of the present invention. The nozzle (20) for the fuel injector (10) herein comprises of the nozzle guide region (108) and the needle guide region (110) in addition to the needle (102) and the nozzle body (104).
[0013] The invention as disclosed and depicted in Fig 3 has the nozzle (20) characterized with a guide ring (112). The guide ring (112) is configured and places such that it is at the operative top of the nozzle guide region (108) of the nozzle (20). Moreover, the nozzle (20) is provided with a recess (114) in the nozzle body (104) wherein said recess (114) located at the operative top of the nozzle guide region (108). The guide ring (112) is places in this recess (114).
[0014] Additionally the guide ring (112) is semicircular, giving it a semicircular cross section, thereby making it partially in contact with the needle guide region (110) of the nozzle (20).
[0015] As per an embodiment of the invention, the guide ring (112) may be made of steel. Additionally, the ring is provided with a limited axil force to seat properly at the nozzle guide region (108). This aids in the needle (102) to be guided between guide ring (112) and the nozzle seat region. Therefore, the contact of needle (102) with the nozzle (20) at the nozzle guide region (108) is minimized. This additionally aids to avoid the one sided wear or rubbing marks at the nozzle guide region (108).
[0016] The embodiment as disclosed here, additionally has a plurality of benefits as disclosed herein. For instance, the guide ring (112) will provide controlled back flow quantity by limiting clearance between nozzle (20), needle (102) and the guide ring (112). Also, the return fuel can be controlled to avoid the fluctuations at the rail pressure for better atomization.
[0017] The invention as disclosed here, can also help in meeting the required emission norms by ensuring better injection quantity. Additionally, by limiting the fuel high back flow the constant fuel tank temperature may also be maintained. Therefore the invention disclosed may also increase the life of nozzle by eliminating the failure due to nozzle guide wear.
[0018] 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.