Claims:We Claim:
1. A restrainer (110) for a nozzle (103) in a fuel injector 105, said restrainer (110) housed in injector body bore (100) and nozzle shaft receiving bore 112 and comprises:
a washer (106) of said fuel injector (105); said washaer abutting a step (108)
located in nozzle shaft receiving bore (112) extending axially from said injector body bore (100) and enclosing said nozzle (103),
said washer (106) and said step (108) coaxial to said nozzle (103).
2. The restrainer 110 of claim 1, wherein said washer (106) and said step 108 are integrated.
3. The restrainer 110 of claim 1, wherein said washer (106) comprises a sleeve extending from said washer into said nozzle shaft receiving bore 112. , Description:Field of the invention
[0001] This invention relates to the field of a fuel injector.
Background of the invention
[0002] A fuel injector comprises injector body and nozzle located within the cylinder bore. The nozzle receives fuel from the high pressure fuel injection pump through injector body. The axis of the nozzle is co-axial with the axis of the fuel injector body and cylinder bore. The fuel injector is held within the cylinder bore by clamping. During the working of the injector, there is possibility of the fuel injector to tilt within the cylinder bore and lose its axial orientation with respect to the cylinder bore because of the clearances between the fuel injector & cylinder bore. This leads to wear of the nozzle because of the lateral load coming on one side of the injector, rubbing marks on the injector body & its components because of misalignment of the axis of the nozzle with the injector body bore in the cylinder head. Hence there is a need to maintain the position of the nozzle during working of the injector to aid for the efficient working of nozzle/injector over its lifetime. Also the injector comprises a sealing washer. There are chances of sealing washer falling into the injector body bore in the cylinder head because of the clearance between the nozzle shaft outer diameter and sealing washer inner diameter.
Brief description of the accompanying drawing
[0003] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:
[0004] FIG. 1 illustrates a restrainer for a nozzle in a fuel injector.
Detailed description of the embodiments
[0005] FIG. 1 illustrates a restrainer 110 for a nozzle 103 in a fuel injector 105. The restrainer 110 is housed in the injector body bore 100 within the cylinder head. The fuel injector (105) comprises an injector body (102), nozzle (103), washer (106) & abutting a step (108). The restrainer is located in nozzle shaft receiving bore (112) extending axially from the injector body bore (100) and enclosing the nozzle (103). The washer (106) and the step (108) are coaxial to the nozzle (103). The injector body 102, injector body bore 100 and the nozzle shaft receiving bore are coaxial to the axis of the nozzle 103.
[0006] The constructional features of the fuel injector 105 with the restrainer 110 will be explained in further detail. The injector comprises an injector body 102, nozzle 103 & restrainer 110. The Injector body bore 100 comprises a bore to accommodate the injector body 102 & nozzle shaft receiving bore 112 to accommodate the nozzle 103 within the cylinder head. The nozzle 103 is assembled along with the injector body 102 is co-axial to the axis of the injector body bore 100. The nozzle 103 injects the high pressure fuel that is received from the high pressure fuel injection pump through injector body 102 into the engine combustion chamber.
[0007] The working of the fuel injector 105 will be explained in further detail. The fuel injector 105 receives pressurized fuel from the high pressure fuel injection pump. The high pressure fuel enters the fuel injector 105 and flows into nozzle 103. The injector comprises a spring (not shown). When the pressure of the fuel exceeds the stiffness of the spring, the nozzle needle lifts 103, resulting in injection of the fuel into the engine combustion chamber. The movement of the nozzle needle 103 is always along the axis of the injector body 102. The restrainer 110 ensures that the nozzle shaft 103 does not rub against the nozzle shaft receiving bore 112 & also ensures that the injector body 102 does not rubs with injector body bore 100.
[0008] The restrainer 110 will be made of copper. In the case of restrainer 110, the amount of copper material present will be more as compared to the injector with sealing washer. Hence there is better heat dissipation which in turn will help to reduce the nozzle 103 tip temperature. Restrainer 110 will ensure proper sealing against combustion gases as compared to injector along with sealing washer by ensuring proper sealing between the injector bottom surface and top surface of the restrainer 110 and between the bottom surface of restrainer 110 with the bottom surface of the injector body bore 100.
[0009] Also, the restrainer 110 will protect the nozzle body collar area against hydrogen embrittlement as compared to injector along with sealing washer because it will not allow the water vapor to enter into the nozzle body collar region as it is having interference fit between the restrainer & nozzle body shaft. This will eliminate the nozzle body collar breakage due to hydrogen embrittlement. In the restrainer 110 as the washer will be located inside the injector body bore 100 and the sleeve in the nozzle shaft receiving bore 108, there are no chances of falling of restrainer 110 because washer 106 is placed in the injector body bore 100 & abutting step of the restrainer 110 is having interference fit with the outer diameter of the nozzle shaft.
[0010] 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 type of high pressure fuel injection pump used. 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.