Claims:We Claim:
1. A high pressure fuel pump (101) driven by a camshaft (102) of the internal combustion engine, the high pressure fuel pump (101) comprising at least an internal shaft sealing ring (103) characterized in that high pressure fuel pump (101) an external shaft sealing ring (104) integrated with a filter (105), where the external shaft sealing ring (104) is placed at the interface between a flange (106) of the high pressure fuel pump (101) and the camshaft (102) of the internal combustion engine.

2. The high pressure fuel pump (101) driven by a camshaft (102) of the internal combustion engine as claimed in claim 1, where the external shaft sealing ring (104) integrated with a filter (105), said filter (105) further comprising a mesh (107) and at least a dustlip (108).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be perform

Field of the invention
[0001] The present disclosure relates to a high pressure fuel pump.

Background of the invention
[0002] Shaft sealing rings (SSR) are used at the interface between engine components and the components of the high pressure fuel pump. Two SSRs known as an internal and an external SSR are deployed on the interface between the engine components (usually a camshaft) and the components of the high pressure fuel pump (usually a flange or the pumpshaft). The engine components are oil lubricated, while the high pressure fuel pump components are fuel lubricated.

[0003] The internal SSR restricts the fuel from the fuel lubricated components of the high pressure fuel pump from flowing towards the engine components. Similarly the external SSR restricts the movement of the oil from the oil lubricated engine components towards the fuel lubricated high pressure fuel components. Sometimes due to bad oil quality used in the lubrication of engine there is particle deposition between the camshaft and the external SSR. These particles cause the external SSR to wear down. This further leads to the mixing of oil in fuel which can damage components of the high pressure fuel pump.

Brief description of the accompanying drawings
[0004] An embodiment of the invention is described with reference to the following accompanying drawing.
[0005] Fig. 1 depicts a high pressure fuel pump (101) driven by a camshaft (102) of an internal combustion engine.

Detailed description of the drawings
[0006] Figure 1 depicts a high pressure fuel pump (101) driven by a camshaft (102) of a internal combustion engine. The high pressure fuel pump (101) comprises an internal shaft sealing ring (103) and at least an external shaft sealing ring (104). The external shaft sealing ring (104) is integrated with a filter (105). The external shaft sealing ring (104) is placed at the interface between a flange (106) of the high pressure fuel pump (101) and the camshaft (102) of the internal combustion engine. The filter (105) of the external shaft sealing ring (104) further comprises a mesh (107) and a dustlip (108).

[0007] The High pressure fuel pump (101) is mounted on engine, driven by chain. The shaft sealing rings (SSR)s are used for coupling of components of the high pressure fuel pump (101) and the internal combustion engine. The flange (106) of the high pressure fuel pump (101) is coupled with camshaft (102) of the internal combustion engine by means of an external SSR (104) and an internal SSR (103). The SSRs are mounted at the interface of the flange (106) with the camshaft (102) using press fit technique.

[0008] The engine components are oil lubricated, while the high pressure fuel pump (101) components are fuel lubricated. The internal SSR (103) restricts the fuel from the fuel lubricated components of the high pressure fuel pump (101) from flowing towards the engine components. Similarly the external SSR (104) restricts the movement of the oil from the oil lubricated engine components from towards the fuel lubricated high pressure fuel components. The filter (105) components integrated with the external SSR (104), filters the oil coming in from the camshaft (102) of the internal combustion engine.

[0009] The dustlip (108) prevents the entry of solid foreign particles from the camshaft (102) of the internal combustion engine into the interface between the camshaft (102) of the internal combustion engine and the flange (106) of the high pressure fuel pump (101). A dustlip (108) is made of rubber or same material as that of the shaft sealing ring. The entry of bigger sized foreign particles is prevented by dustlip (108). The smaller size particles, which are sticky due to the lubrication oil, gradually seep towards the external SSR (104). The mesh (107) prevents the entry of these smaller sized particles. The size of the mesh (107) is chosen based on the application severity and robustness of the pump. For example, in an embodiment the size of mesh (107) is chosen as 100 microns.

[0010] This idea to develop a high pressure fuel pump (101) with modification to the construction of the external SSR (104) averts quality issues by providing clean engine oil to external SSR (104). Further this prevents the interposition of particles between camshaft (102) and external SSR (104). This prevents the wearing down of the external SSR (104), thereby increasing the robustness of the external SSR (104).

[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 this high pressure fuel pump (101) are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.