Claims:CLAIMS

We Claim

1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
a housing (12);
a barrel (14) positioned within said housing (12) and adapted to house a plunger (16) therein, the barrel (14) comprising a head portion (18), a collar portion (20) that is secured to the head portion (18) and extending from the head portion (18), and a shaft portion (22) that is secured to the collar portion (20) and extending from the collar portion (20), wherein the plunger (16) is adapted to reciprocate within the barrel (14) of the high pressure fuel pump (10); characterized in that
a flat shaped surface (24) developed on a circumference of the collar portion (20) of said barrel (14), the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14) adapted to secure said barrel (14) within said housing (12), thereby preventing said barrel (14) from rotating within said housing (12) of said high pressure fuel pump (10).

2. The high pressure fuel pump (10) in accordance with Claim 1, further comprising a flat shaped surface (26) developed on a circumference of a guiding bore of said housing (12), the flat shaped surface (26) developed on the circumference of the guiding bore of said housing (12) adapted to be aligned with the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14), thereby preventing said barrel (14) from rotating within said housing (12) of said high pressure fuel pump (10).

3. The high pressure fuel pump (10) in accordance with Claim 2, wherein the flat shaped surface (26) developed on the circumference of the guiding bore of said housing (12) and the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14) are machined by means of one of a grinding operation, a milling operation, and a shaping operation.

4. The high pressure fuel pump (10) in accordance with Claim 2, further comprising a circular shaped portion (28) developed on the circumference of the collar portion (20) of said barrel (14) and adjoining the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14), the circular shaped portion (28) developed on the circumference of the collar portion (20) of said barrel (14) adapted to secure said barrel (14) within said housing (12).

5. The high pressure fuel pump (10) in accordance with Claim 4, further comprising a circular shaped portion (30) developed on the circumference of the guiding bore of said housing (12) and adjoining the flat shaped surface (26) developed on the circumference of the guiding bore of said housing (12), the circular shaped portion (30) developed on the circumference of the guiding bore of said housing (12) adapted to be aligned to the circular shaped portion (28) developed on the circumference of the collar portion (20) of said barrel (14).

6. The high pressure fuel pump (10) in accordance with Claim 5, wherein said barrel (14) is inserted through said housing (12) such that flat shaped surface (26) developed on the circumference of the guiding bore of said housing (12) guides the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14), thereby aligning the flat shaped surface (26) developed on the circumference of the guiding bore of said housing (12) with the flat shaped surface (24) developed on the circumference of the collar portion (20) of said barrel (14), thereby preventing said barrel (14) from rotating within said housing (12) of said high pressure fuel pump (10).
, 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 a high pressure fuel pump, and more specifically to flat shaped portions that are defined in a barrel and in a housing of the high pressure fuel pump.

Background of the invention
[0002] KR 101204635 B1 describes a fuel injection pump with an umbrella plunger guide that is provided to prevent lubricants from becoming polluted due to mixed oil as the sections for the lubricants, mixed oil, and fuel are surely divided. A fuel injection pump comprises a pump housing and a pump barrel. A fuel suction port and a plunger guide are installed in the pump housing. The pump barrel is inserted into the pump housing. A plunger that is coupled to the plunger guide is operated according to the pump barrel, and high pressure fuel is injected into an engine. The plunger guide comprises a spring guide, a plurality of drain holes, and an umbrella part. The plurality of drain holes is formed on the bottom of the plunger guide corresponding to the through hole of the spring guide. The umbrella part protrudes along the circumference, and guides the mixed oil passing through the drain holes.

Brief description of the accompanying drawings
[0003] Figure 1 illustrates a barrel of a high pressure fuel pump in one embodiment of the invention.
[0004] Figure 2 illustrates a top view of a high pressure fuel pump in one embodiment of the invention.

Detailed description of the embodiments
[0005] A high pressure fuel pump 10 is described. The high pressure fuel pump 10 comprises a housing 12, and a barrel 14 positioned within the housing 12 and adapted to house a plunger 16 therein. The barrel 14 comprises a head portion 18, a collar portion 20 that is secured to the head portion 18 and extending from the head portion 18, and a shaft portion 22 that is secured to the collar portion 20 and extending from the collar portion 20. The plunger 16 is adapted to reciprocate within the barrel 14 of the high pressure fuel pump 10. A flat shaped surface 24 is developed on a circumference of the collar portion 20 of the barrel 14. The flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 is adapted to secure the barrel 14 within the housing 12, thereby preventing the barrel 14 from rotating within the housing 12 of the high pressure fuel pump 10.

[0006] Figure 1 illustrates a barrel 14 of a high pressure fuel pump 10 in one embodiment of the invention. The high pressure fuel pump 10 comprises a housing 12. A barrel 14 is positioned within the housing 12 and is adapted to house a plunger 16 therein. More specifically, the plunger 16 is guided within a bore that is defined in the barrel 14 that is positioned within the housing 12. In an exemplary embodiment, the barrel 14 comprises a head portion 18 that is secured to a top portion of the housing 12. A collar portion 20 of the barrel 14 that is secured to the head portion 18 extends from the head portion 18 and away from the head portion 18. The collar portion 20 of the barrel 14 is guided within the housing 12 of the high pressure fuel pump 10 as will be explained in more detail hereinafter. A shaft portion 22 that is secured to the collar portion 20 of the barrel extends from the collar portion 20 and away from the collar portion 20. In the exemplary embodiment, the plunger 16 is adapted to reciprocate within the barrel 14 of the high pressure fuel pump 10. The translation of the plunger 16 from its bottom dead center position to its top dead center position causes the pressurization and delivery of fuel from the high pressure fuel pump 10 to the fuel injector.

[0007] Figure 2 illustrates a top view of the high pressure fuel pump in one embodiment of the invention. In the exemplary embodiment, a flat shaped surface 24 is developed on a circumference of the collar portion 20 of the barrel 14. More specifically, the flat shaped surface 24 is developed at a user defined width on the circumference of the collar portion 20 of the barrel 14. The width of the flat shaped surface 24 developed on the collar portion 20 of the barrel 14 is so designed as to snugly secure the barrel 14 within the housing 12. The flat shaped surface 24 developed on the collar portion 20 of the barrel 14 that snugly secures the barrel 14 within the housing 12 prevents the barrel 14 from rotating within the housing 12 of the high pressure fuel pump 10 as will be explained in more detail hereinafter.

[0008] In an exemplary embodiment, a flat shaped surface 26 is developed on a circumference of a guiding bore of the housing 12. During assembly of the barrel 14 within the housing 12 of the high pressure fuel pump 10, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 is adapted to be aligned with the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14. The alignment of the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 with the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 prevents the barrel 14 from rotating within the housing 12 of the high pressure fuel pump 10. In an exemplary embodiment, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12, as well as the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 are machined by means of a grinding operation that is initiated by a grinding wheel. In an alternate exemplary embodiment, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12, as well as the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 are machined by means of a milling operation that is initiated by a milling cutter. In yet another alternate exemplary embodiment, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12, as well as the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 are machined by means of a shaping operation that is initiated by a mechanical shaper.

[0009] In an exemplary embodiment, a circular shaped portion 28 is developed on the circumference of the collar portion 20 of the barrel 14. More specifically, the circular shaped portion 28 is adjoining the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14. The circular shaped portion 28 that is developed on the circumference of the collar portion 20 of the barrel 14 is adapted to secure the barrel 14 within the housing 12 as will be explained in more detail below. In addition, a circular shaped portion 30 is developed on the circumference of the guiding bore of the housing 12. More specifically, the circular shaped portion 30 is adjoining the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12. The circular shaped portion 30 that is developed on the circumference of the guiding bore of the housing 12 is adapted to be aligned to the circular shaped portion 28 that is developed on the circumference of the collar portion 20 of the barrel 14 of the high pressure fuel pump 10. Therefore, once the barrel 14 is inserted within the housing 12 of the high pressure fuel pump 10, the barrel 14 is prevented from rotating within the housing 12 due to an interference that is developed between the the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 and the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12. The flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 is aligned against the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12, thereby preventing the barrel 14 from rotating within the housing 12 of the high pressure fuel pump 10.

[0010] In an exemplary embodiment, the barrel 14 is inserted through the housing 12 such that flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 guides the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14. Therefore, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 aligns with the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14. The alignment of the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 with the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 creates an interference that prevents the barrel 14 from rotating within the housing 12 of the high pressure fuel pump 10.

[0011] A working of the high pressure fuel pump 10 is now described as an example. When the barrel 14 is inserted through the housing 12, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 guides the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14. Therefore all along the longitudinal axis of the high pressure fuel pump 10, the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 is smoothly guided within the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12, thereby aligning the barrel 14 with the housing 12 when the barrel 14 is completely seated within the housing 12 of the high pressure fuel pump 10. Similarly, all along the longitudinal axis of the high pressure fuel pump 10, the circular shaped portion 28 that is developed on the circumference of the collar portion 20 of the barrel 14 is smoothly guided within the circular shaped portion 30 that is developed on the circumference of the guiding bore of the housing 12, thereby aligning the barrel 14 within the housing 12 when the barrel 14 is completely seated within the housing 12 of the high pressure fuel pump 10. Therefore, when a torsional load is acted on the barrel 14, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 prevents the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 from sliding past it, thereby preventing the barrel 14 to rotate further within the housing 12 of the high pressure fuel pump 10. Moreover, the flat shaped surface 26 that is developed on the circumference of the guiding bore of the housing 12 acts as a guide, thereby causing the flat shaped surface 24 that is developed on the circumference of the collar portion 20 of the barrel 14 to align perfectly with the housing 12, thereby securing the orientation of the barrel 14 of the high pressure fuel pump 10 within the housing 12. As the orientation of the barrel 14 with respect to the housing 12 is secured, the plunger 16 can be safely oriented and positioned at a required orientation within the barrel 14 of the high pressure fuel pump 10.

[0012] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.