Claims:CLAIMS
We Claim:
1. A fuel injector (200) assembly, said fuel injector 200 assembly configured to be mounted on a cylinder head 202 of an engine, and comprising at least:
a nozzle holder 204 adapted to be mechanically engaged to a nozzle body 206, said nozzle body 206 adapted to be located within cylinder head 202 of said engine via a nut 208; characterized in that
a sleeve 210 mechanically engaged to said nut 208 along the length of said sleeve 210, and abutting a sealing washer 212 along the diameter of said sleeve 210, said sealing washer 212 located within said cylinder head 202; and a spring element 214 located in-between said sleeve 210 and said nut 208.

2. The fuel injector 200 of claim 1, wherein said sleeve 210 is integrated with said nut 208.

, 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 the field of a fuel injector assembly.

Background of the invention
[0002] FIG. 1 illustrates a fuel injector according to state of art .An injector 100 is used to inject pressurized fuel into the internal combustion engine. The injector 100 may be mounted on or within the cylinder head 102 of the internal combustion engine. In order to prevent combustion gases from entering into the injector, a sealing washer 104 is used. The sealing washer 104 also supports the injector 100 within the cylinder head 102. The injector 100 is assembled onto the cylinder head 102 with a clamp assembly (not shown) by providing sufficient torque to the bolt tightened to the clamp assembly so that a force between 8 to 15kN is achieved between sealing washer and cylinder head sealing surface. This force ensures that there is no combustion gas leakage through the clearance between injector 100 and cylinder head 102 during combustion process inside the engine cylinder.

[0003]The thickness of the sealing washer 104 is decided based on the required performance of the engine and emission targets. Sealing washers of varying thickness are used during development trials to compare the performance and emission results and to fix the thickness of the sealing washer based on results for use during real time condition. Once the sealing washer thickness is chosen for a particular engine configuration and application, subsequently, nozzle tip protrusion 106 (NTP) is also fixed.

[0004] Nozzle tip protrusion (NTP) 106 defines the spray-hitting plane and directly affects the performance and emission. Hence, very less/no variation in NTP 106 is preferred for better performance of the engine combustion characteristics, which directly affects emission, performance and drivability. However, due to manufacturing tolerances of the sealing washer 104, the cylinder head 102 and nozzle shaft length 105, NTP 104 varies for all the cylinders of the internal combustion engine, thereby affecting spray characteristics.

Brief description of the accompanying drawing
[0005] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0006] FIG. 1 illustrates a fuel injector according to state of art; and

[0007] FIG. 2 illustrates a fuel injector assembly according to an embodiment of the invention.

Detailed description of the embodiments
[0008] FIG. 2 illustrates a fuel injector 200 according to an embodiment of the invention. The fuel injector 200 assembly is configured to be mounted on a cylinder head 202 of an engine and comprises at least a nozzle holder 204 adapted to be mechanically engaged to a nozzle body 206. The nozzle body 206 is adapted to be located within the cylinder head 202 of the engine via a nut 208. A sleeve 210 is mechanically engaged to the nut 208 along the length of the sleeve 210, the sleeve abuts a sealing washer 212 along the diameter of the sleeve 210. The sealing washer is located within the cylinder head 202. A spring element 214 is located in-between the sleeve 210 and the nut 208. In an embodiment the sleeve 210 may be integrated with the nut 208.

[0009]The constructional features of the fuel injector 200 assembly will be disclosed in further detail. The fuel injector 200 assembly comprises a nozzle holder 204. The function of the nozzle holder 204 is to receive high pressure fuel from the common rail. The nozzle holder 204 also comprises a spindle 207 that may be actuated by fuel pressure difference. The nozzle holder 204 is adapted to be mechanically engaged to the nozzle body 206. The nozzle body 206 is adapted to be located within the cylinder head 202 of the engine via a nut 208. The nozzle body 206 comprises a nozzle valve 211, the movement of the nozzle valve 211 causes the spray hole (not shown) in the fuel injector 200 to open a path for fuel to flow from the fuel injector 200 into the combustion chamber of the engine cylinder.

[0010]The sleeve 210 is mechanically engaged to the nut 208 along the length of the sleeve 210 by means of threads. The sleeve 210 abuts a sealing washer 212 along the diameter of the sleeve 210. The sealing washer 212 is located within the cylinder head 202. The spring element 214 is located in-between the sleeve 210 and the nut 208, which is integrated in the sleeve 210 to prevent backlash.

[0011]The working of the fuel injector 200 assembly will be explained in further detail. The fuel injector 200 is used to inject pressurized fuel into the engine cylinder. In order to achieve the same, the nozzle tip of the fuel injector 200 needs to project into the engine cylinder for spraying fuel in atomized form as disclosed in FIG.2 This projection is called nozzle tip projection (NTP)and/ or protrusion 209. In order to avoid change in nozzle tip protrusion 209 due to change in tolerances, gap between the nut 208 and sleeve 210 is adjusted by rotating the sleeve 210. The angle of rotation of sleeve 210 is achieved according to the formula, angle= (k*360)/p. Where P=Pitch of the sleeve, k=correction factor. ‘K’ correction factor is the undesired/change in required NTP due to tolerances. The rotation of sleeve 210 results in the change in gap between sleeve 210 and nut 208 which in turn helps in achieving the required NTP. Hence, the rotation of the sleeve 210 compensates for the variation in nozzle tip protrusion due to change in tolerances. The function of spring element 214 is to ensure that there is no backlash and for precise adjustment of nozzle tip protrusion.

[0012]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of injector used and the material used for sealing washer. 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.