Claims:We Claim

1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
a housing (12);
a fuel outlet valve (14) inserted within a bore (16) that is defined in said housing (12), said fuel outlet valve (14) comprising:
a first portion (18) having a first diameter;
a second portion (20) that is secured to said first portion (18) and extending away from said first portion (18), said second portion (20) having a second diameter that is greater than the first diameter;
a third portion (22) that is secured to the second portion (20) and extending away from the second portion (20), said third portion (22) having a third diameter that is smaller than the second diameter, and wherein said third portion (22) is inserted within said housing (12) of said high pressure fuel pump (10);
a fourth portion (24) that is secured to said third portion (22) and extending away from said third portion (22), said fourth portion (24) having a fourth diameter that is greater than the third diameter, and wherein said fourth portion (24) is inserted within said housing (12) of said high pressure fuel pump (10); characterized in that
a projection (26) defined on said third portion (22) of said fuel outlet valve (14), wherein said projection (26) is located between said second portion (20) and said fourth portion (24) of said fuel outlet valve (14) and is adapted to restrict a quantity of pressurized fuel that is delivered from said high pressure fuel pump (10).

2. The high pressure fuel pump (10) in accordance with Claim 1 wherein said projection (26) is formed on said third portion (22) of said high pressure fuel pump (10) by machining said projection (26) on said third portion (22) of said high pressure fuel pump (10).

3. The high pressure fuel pump (10) in accordance with Claim 1 wherein said projection (26) is a notch shaped portion that facilitates preventing a flow of fuel from said first portion (18) to said third portion (22) of said fuel outlet valve (14).

4. A fuel outlet valve (14) for a high pressure fuel pump (10), said fuel outlet valve (14) in flow communication with a pumping chamber of said high pressure fuel pump (10), said fuel outlet valve (14) comprising:
a first portion (18) having a first diameter;
a second portion (20) that is secured to the first portion (18) and extending away from the first portion (18), said second portion (20) having a second diameter that is greater than the first diameter;
a third portion (22) that is secured to the second portion (20) and extending away from the second portion (20), said third portion (22) having a third diameter that is smaller than the second diameter, and wherein said third portion (22) is inserted within a housing (12) of said high pressure fuel pump (10);
a fourth portion (24) that is secured to said third portion (22) and extending away from said third portion (22), said fourth portion (24) having a fourth diameter that is greater than the third diameter, and wherein said fourth portion (24) is inserted within said housing (12) of said high pressure fuel pump (10); characterized in that
a projection (26) defined on said third portion (22) of said fuel outlet valve (14), wherein said projection (26) is located between said second portion (20) and said fourth portion (24) of said high pressure fuel pump (10) and is adapted to restrict a quantity of pressurized fuel that is delivered from 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 a fuel outlet valve of the high pressure fuel pump.

Background of the invention
[0002] US 2019234363 A describes various embodiments that include a high pressure port for a high pressure fuel pump of a fuel injection system comprising an outlet valve with an outlet valve element opening in a first direction and cooperating with an outlet valve seat to close the outlet valve; and a pressure limiting valve with a pressure limiting valve element opening in a second direction opposite the first direction and cooperating with a pressure limiting valve seat to close the pressure limiting valve. The outlet valve element comprises the pressure limiting valve seat.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a high pressure fuel pump depicting the fuel outlet valve of the high pressure fuel pump in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a high pressure fuel pump 10 depicting the fuel outlet valve 14 of the high pressure fuel pump 10 in one embodiment of the invention. The high pressure fuel pump 10 comprises a housing 12, and a fuel outlet valve 14 inserted within a bore 16 that is defined in the housing 12. The fuel outlet valve 14 comprises a first portion 18 having a first diameter, and a second portion 20 that is secured to the first portion 18 and extending away from the first portion 18, the second portion 20 having a second diameter that is greater than the first diameter. The fuel outlet valve 14 comprises a third portion 22 that is secured to the second portion 20 and extending away from the second portion 20, the third portion 22 having a third diameter that is smaller than the second diameter, and wherein the third portion 22 is inserted within the housing 12 of the high pressure fuel pump 10. Moreover, the fuel outlet valve 14 comprises a fourth portion 24 that is secured to the third portion 22 and extends away from the third portion 22, the fourth portion 24 having a fourth diameter that is greater than the third diameter, and wherein the fourth portion 24 is inserted within the housing 12 of the high pressure fuel pump 10. A projection 26 is defined on the third portion 22 of the fuel outlet valve 14, wherein the projection 26 is located between the second portion 20 and the fourth portion 24 of the high pressure fuel pump 10, and is adapted to restrict a quantity of pressurized fuel that is delivered from the high pressure fuel pump 10 to an engine.

[0005] The high pressure fuel pump 10 comprises a housing 12. In the exemplary embodiment, a fuel outlet valve 14 is inserted within a bore 16 that is defined in the housing 12 and in flow communication with a pumping chamber of the high pressure fuel pump 10. More specifically, the fuel outlet valve 14 regulates the flow of fuel from the pumping chamber of the high pressure fuel pump 10 to a fuel injector for injecting the fuel thereof into an engine cylinder. The fuel outlet valve 14 comprises a first portion 18 having a first diameter. A second portion 20 is secured to the first portion 18 and extends away from the first portion 18. In the exemplary embodiment, the second portion 20 has a second diameter which is greater than the first diameter. A third portion 22 is secured to the second portion 20 and extends away from the second portion 20. In the exemplary embodiment, the third portion 22 has a third diameter which is smaller than the second diameter, and is inserted within the bore 16 that is defined in the housing 12 of the high pressure fuel pump 10. A fourth portion 24 is secured to the third portion 22 and extends away from the third portion 22. In the exemplary embodiment, the fourth portion 24 has a fourth diameter that is greater than the third diameter, and is inserted within the bore 16 that is defined in the housing 12 of the high pressure fuel pump 10. The terms “secured” as described herein may refer to the first portion, the second portion, the third portion, and the fourth portion that are each attached to each other by means of an external fastener, or may refer to the first portion, the second portion, the third portion, and the fourth portion that are each integrally attached to each other by machining each portion on a single block of metal.

[0006] A projection 26 is defined on the third portion 22 of the fuel outlet valve 14. In the exemplary embodiment, the projection 26 is located between the second portion 20 and the fourth portion 24 of the high pressure fuel pump 10 and is adapted to restrict a quantity of pressurized fuel that is delivered from the high pressure fuel pump 10. In an exemplary embodiment, the projection 26 is formed on the third portion 22 of the high pressure fuel pump 10 by machining the projection 26 on the third portion 22 of the high pressure fuel pump 10 during the manufacturing stage of the fuel outlet valve 14. The projection 26 is a notch shaped portion that facilitates preventing a flow of fuel from the second portion 20 to the fourth portion 24 of the fuel outlet valve 14 via the third portion 22. More specifically, when the fuel outlet valve 14 is lifted upwardly due to the pressure of the fuel in the pumping chamber of the high pressure fuel pump 10, only a limited quantity of fuel is channeled out of the space between the fuel outlet valve 14 and the housing 12 of the high pressure fuel pump 10 to the fuel injector of the engine. Only the fuel that is present between the projection 26 and the second portion 20 is supplied to the engine while the remaining fuel is retained within the space between the projection 26 and the fourth portion 24 as will be explained in further detail below.

[0007] The fuel outlet valve 14 is inserted within the housing 12 of the high pressure fuel pump 10. More specifically, the third portion 22 and the fourth portion 24 of the fuel outlet valve 14 is inserted within the bore 16 that is defined in the housing 12. After the third portion 22 of the fuel outlet valve 14 is inserted within the bore 16 that is defined within the housing 12, a tapered portion of the second portion 20 is in sealing contact with the housing 12 of the fuel outlet valve 14. As fuel flows from the pumping chamber of the high pressure fuel pump 10, the fuel is channeled into the space between the third portion 22 of the fuel outlet valve 14 and the housing 12 of the high pressure fuel pump 10. More specifically, the fuel is channeled into the space between the third portion 22 of the fuel outlet valve 14 and the housing 12 of the high pressure fuel pump 10 such that a portion of the fuel is channeled into the space above the projection 26 that is between the second portion 20 and the projection 26 which another potion of the fuel is channeled into the space below the projection 26 that is between the projection 26 and the fourth portion 24 and is retained therein. As the fuel outlet valve 14 translates upwardly as the pressure of the fuel in the pumping chamber of the high pressure fuel pump 10 increases above a threshold limit, the projection 26 is translated in the direction opposite to that of the pumping chamber of the high pressure fuel pump 10. As the projection 26 translates in the direction opposite to the pumping chamber of the high pressure fuel pump 10, the fuel that is present in the space between the projection 26 and the second portion 20 of the fuel outlet valve 14 is delivered to the fuel injector of the high pressure fuel pump 10.

[0008] Therefore, due to the presence of the projection 26, the fuel that is present in the space between the projection 26 and the fourth portion 24 of the fuel outlet valve 14 is retained therein, and is not discharged to the fuel injector. At the end of the working stroke of the high pressure fuel pump 10, the fuel outlet valve 14 translates in the direction of the pumping chamber of the high pressure fuel pump 10. Therein, the tapered portion of the second portion 20 of the fuel outlet valve 24 is in sealing contact with the housing 12 of the high pressure fuel pump 10. Fresh fuel is channeled from the pumping chamber of the high pressure fuel pump 10 into the space between the second portion 20 and the projection 26 via the space between the fourth portion 24 of the fuel outlet valve 14 and the housing 12, and the space between the projection 26 and the fourth portion 24 of the fuel inlet valve 14. More specifically, the fuel that flows into the space between the projection and the fourth portion 24 via the space that is defined between the fourth portion 24 and the housing 12 first fills the space between the projection 26 and the fourth portion 24 of the fuel outlet valve 14. Once the fuel has completely filled the space between the projection 26 and the fourth portion 24 of the fuel outlet valve 14, the excess pressurized fuel flows into the space that is defined between the projection 26 and the second portion 20 until the space between the projection 26 and the second portion 20 is completely filled with fuel. Once the space between the projection 26 and the second portion 20 is completely filled with fuel, the cycle repeats once more with the lifting of the fuel inlet valve 14 when the pressure of the fuel that is present in the pumping chamber of the high pressure fuel pump increases above its threshold pressure limit.

[0009] 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.