Claims:CLAIMS

We Claim

1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
a housing (12);
a barrel (13) positioned within said housing (12);
a plunger (14) positioned within said barrel (13), said plunger (14) adapted to reciprocate within an element chamber (15) defined within said barrel (13);
a vertical groove (16) defined in said plunger (14), the vertical groove (16) adapted to extend along a sidewall of said plunger (14);
a helix groove (18) in flow communication with the vertical groove (16) and extending angularly along a sidewall of said plunger (14), the helix groove (18) adapted to control a quantity of pressurized fuel that is delivered from the element chamber (15) defined within said barrel (13) to a fuel injector; characterized in that
an LLA groove (20) defined at a top portion (22) of said plunger (14) and extending from a portion within said plunger (14) to an outer circumference of said plunger (14), the LLA groove (20) adapted to retard a timing of pressurized fuel that is delivered from the element chamber (15) of the high pressure fuel pump (10) to a fuel injector.

2. The high pressure fuel pump (10) in accordance with Claim 1, wherein the LLA groove (20) comprises an angular shaped portion (24) that extends from a base portion (26) of the LLA groove (20) until the top portion (22) of said plunger (14)of said high pressure fuel pump (10).

3. The high pressure fuel pump (10) in accordance with Claim 2, wherein the angle of the angular shaped portion (24) of the LLA groove (20) is user defined based on a user specific application.

4. The high pressure fuel pump (10) in accordance with Claim 1, wherein the LLA groove (20) comprises an angular shaped portion (24) that extends from a base portion (26) of the LLA groove (20) until the top portion (22) of said plunger (14) of said high pressure fuel pump (10) from one end (28) of an outer circumference of said plunger (14) to an opposite end (30) of the outer circumference of said plunger (14).

5. The high pressure fuel pump (10) in accordance with Claim 4, wherein the angular shaped portion (24) of the LLA groove (20) that extends from the base portion (26) of the LLA groove (20) until the top portion (22) of said plunger (14) of said high pressure fuel pump (10) facilitates delivering a fixed quantity of pressurized fuel for each displacement of a fuel inlet port that is defined through said barrel (13) of said high pressure fuel pump (10) as it is displaced along the angular shaped portion (24) of the LLA groove (20) when the fuel inlet port translates from a top of the angular shaped portion (24) of the LLA groove (20) until the fuel inlet port translates to a required stroke length of the plunger (14) that corresponds to a required quantity of pressurized fuel that is to be delivered from the element chamber of the high pressure fuel pump (10) to a fuel injector.

6. The high pressure fuel pump (10) in accordance with Claim 5, wherein the quantity of pressurized fuel that is required to be delivered from the element chamber (15) of the high pressure fuel pump (10) to the fuel injector decreases linearly from when the fuel inlet port translates from the top portion (22) of said plunger (14) of said high pressure fuel pump (10) to a required stroke length of the plunger (14), until the fuel inlet port translates from the base portion (26) of the LLA groove (20) to the required stroke length of the plunger (14).
, 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 an angularly shaped LLA groove defined at a top portion of a plunger of the high pressure fuel pump.

Background of the invention
[0002] IN 202141013909 describes a high pressure fuel pump. The high pressure fuel pump comprises a housing. An element is positioned within the housing, the element adapted to reciprocate within the housing. A vertical groove is defined in the element, the vertical groove adapted to extend along a sidewall of the element. A reverse helix groove is in flow communication with the vertical groove and extends angularly along a sidewall of the element. The reverse helix groove extends upwardly towards a top of the element from the vertical groove at one end to an opposite second end of the reverse helix groove at its opposite second end.

Brief description of the accompanying drawings
[0003] Figure 1 depicts a high pressure fuel pump illustrating an angularly shaped LLA groove defined at a top portion of a plunger in one embodiment of the invention.
[0004] Figure 2 depicts the plunger of the high pressure fuel pump illustrating the angularly shaped LLA groove defined at the top portion of the plunger 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. A barrel 13 is positioned within the housing 12. A plunger 14 is positioned within the barrel 13, the plunger 14 adapted to reciprocate within an element chamber 15 defined within the barrel 13. A vertical groove 16 is defined in the plunger 14, the vertical groove 16 adapted to extend along a sidewall of the plunger 14. A helix groove 18 is in flow communication with the vertical groove 16 and extends angularly along a sidewall of the plunger 14. The helix groove 18 is adapted to control a quantity of pressurized fuel from the element chamber 15 defined within the barrel 13 to a fuel injector. An LLA groove 20 is defined at a top portion 22 of the plunger 14 and extends from a portion within the plunger 14 to an outer circumference of the plunger 14. The LLA groove 20 is adapted to advance or retard a timing of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to a fuel injector.

[0006] Figure 1 depicts a plunger 14 of a high pressure fuel pump 10 illustrating the angularly shaped LLA groove 20 defined at the top portion 22 of the plunger 14 in one embodiment of the invention. The high pressure fuel pump 10 comprises a housing 12. A barrel 13 is positioned within the housing 12 and is secured to the housing 12. A plunger 14 is positioned within the barrel 13, wherein the plunger 14 is adapted to reciprocate within the barrel 13 and translate from the bottom dead center position to the top dead center position of the high pressure fuel pump 10. As the plunger 14 translates from its bottom dead center position to its top dead center position, fuel is delivered from the high pressure fuel pump 10 to a fuel injector, and therein supplied to an engine cylinder for combustion. A vertical groove 16 is defined in the plunger 14, wherein the vertical groove 16 is adapted to extend along a sidewall of the plunger 14. The vertical groove 16 is adapted to channel pressurized fuel from the pumping chamber of the high pressure fuel pump 10 to a helix groove 18 that is in flow communication with the vertical groove 16. From the helix groove 18, the pressurized fuel is discharged from the pumping chamber to the fuel gallery of the high pressure fuel pump 10 via a fuel inlet port (not shown). Therefore, the helix groove 18 is adapted to control a quantity of pressurized fuel from the element chamber 15 defined within the barrel 13 to a fuel injector.
[0007] In an exemplary embodiment, an LLA groove 20 is defined at a top portion 22 of the plunger 14. The LLA groove 20 extends from a portion within the plunger 14 to an outer circumference of the plunger 14. The LLA groove 20 is adapted to advance or retard a timing of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to a fuel injector. In an exemplary embodiment, the LLA groove 20 comprises an angular shaped portion 24 that extends from a base portion 26 of the LLA groove 20 and culminates at the top portion 22 of the plunger 14 of the high pressure fuel pump 10. Therefore, the angular shaped portion 24 that extends from the base portion 26 of the LLA groove 20 and culminates at the top portion 22 of the plunger of the high pressure fuel pump 10 comprises a slope that extends from the base portion 26 of the LLA groove 20 until the top portion 22 of the plunger 14 of the high pressure fuel pump 10.

[0008] In an exemplary embodiment, the angle of the angular shaped portion 24 of the LLA groove 20 is user defined based on a user specific application. More specifically, the LLA groove 20 comprises an angular shaped portion 24 that extends from the base portion 26 of the LLA groove 20 until the top portion 22 of the plunger 14 of the high pressure fuel pump 10. More specifically, the LLA groove 20 extends from one end 28 of an outer circumference of the plunger 14 to an opposite end 30 of the outer circumference of the plunger 14 such that a angular shaped portion 24 is defined between the top portion 22 of the plunger 14 of the high pressure fuel pump 10 and the base portion 26 of the LLA groove 20.

[0009] The angular shaped portion 24 of the LLA groove 20 that extends from the base portion 26 of the LLA groove 20 until the top portion 22 of the plunger 14 of the high pressure fuel pump 10 facilitates delivering a fixed quantity of pressurized fuel for each displacement of a fuel inlet port (not shown) that is defined through the barrel 13 of the high pressure fuel pump 10 as it traverses along the angular shaped portion 24 of the LLA groove 20. More specifically, as the fuel inlet port translates towards the LLA groove 20 from the solid outer circumference of the plunger 14 due to the rotation of the plunger 14 of the high pressure fuel pump 10, the fuel inlet port translates from the top portion 22 of the plunger 14 of the high pressure fuel pump 10 to the base portion 26 of the LLA groove 20 via the angular shaped portion 24 of the LLA groove 20. Therefore, as the plunger 14 translates from a particular point defined at the top portion of the angular shaped portion 24 of the LLA groove 20 until the fuel inlet port translates to a required stroke length of the plunger 14 that corresponds to a required quantity of pressurized fuel that is to be delivered from the element chamber 15 of the high pressure fuel pump 10 to a fuel injector, the quantity of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector is equal to a constant value. As the plunger translates from a particular point defined at the top portion of the angular shaped portion 24 of the LLA groove 20 that is adjacent to the previous point defined at the top portion of the angular shaped portion 24 of the LLA groove 20 and directed towards the base portion 26 of the LLA groove 20 until the fuel inlet port translates to the same stroke length of the plunger 14 that corresponds to a required quantity of pressurized fuel that is to be delivered from the element chamber 15 of the high pressure fuel pump 10 to a fuel injector, the quantity of pressurized fuel that is actually delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector is equal to a constant value which is lesser than the previous quantity of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector. Therefore, as the plunger 14 translates from a particular point defined at the base portion of the LLA groove 20 until the fuel inlet port translates to a required stroke length of the plunger 14 that corresponds to a required quantity of pressurized fuel that is to be delivered from the element chamber 15 of the high pressure fuel pump 10 to a fuel injector, the quantity of pressurized fuel that is actually delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector is equal to a constant value that is equal to a minimum quantity of pressurized fuel that can be delivered from the element chamber 15 of the high pressure fuel pump 10. The inclined LLA groove during its interaction with the circular inlet port, traces a straight line parallel to the inclination of the groove itself.

[0010] In an exemplary embodiment, the quantity of pressurized fuel that is required to be delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector decreases linearly from when the fuel inlet port translates from the top portion 22 of the plunger 14 of the high pressure fuel pump 10 to a required stroke length of the plunger 14, until the fuel inlet port translates from the base portion 26 of the LLA groove 20 to the required stroke length of the plunger 14. As an example, the quantity of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector when the fuel inlet port translates from the top portion 22 of the plunger 14 of the high pressure fuel pump 10 to the required stroke length of the plunger 14 is equal to 100 units of fuel. Similarly, the quantity of pressurized fuel that is delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector when the fuel inlet port translates from the base portion 26 of the LLA groove 20 of the high pressure fuel pump 10 to the same stroke length of the plunger 14 is equal to 75 units of fuel. Between the top portion 22 of the plunger 14 of the high pressure fuel pump 10 and the base portion 26 of the LLA groove 20 of the high pressure fuel pump 10 until the fuel inlet port translates to the required stroke length of the plunger 14, the quantity of pressurized fuel that will be effectively delivered from the element chamber 15 of the high pressure fuel pump 10 to the fuel injector will decrease linearly from 100 units of fuel to 75 units of fuel respectively.

[0011] 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.