Claims:
We Claim

1. A high pressure fuel pump (10), said high pressure fuel pump (10) comprising:
a housing (12);
a stepped groove (14) defined within said housing (12), the stepped groove (14) adapted to extend from a top of said housing (12) to a bottom of said housing (12); characterized in that
an L-shaped groove (16) defined within the stepped groove (14), a vertical portion (18) of the L-shaped groove (16) adapted to originate from the top of said housing (12) and extending partially along a length of the stepped groove (14), a horizontal portion (20) of the L-shaped groove (16) adapted to extend from the vertical portion (18) of the L-shaped groove (16) that is proximate to the top of said housing (12) and culminates at an end of a width of the stepped groove (14);
a locking tool (22) comprising a step shaped portion (24) and a locking pin (26) extending radially outwardly from the locking tool (22), the step shaped portion (24) of said locking tool (22) inserted and aligned with the stepped groove (14) defined in said housing (12), an end of said locking tool (22) adapted to compress against an indentation (28) that is defined in a control sleeve (30) that is secured to a plunger (32) of said high pressure fuel pump (10), the compression of the end of said locking tool (22) against the indentation (28) that is defined in said control sleeve (30) facilitates arresting a movement of said control sleeve (30) during an assembly of said high pressure fuel pump (10) within an engine.

2. The high pressure fuel pump (10) in accordance with Claim 1, wherein the locking pin (26) that extends radially outwardly from the locking tool (22) is translated within the vertical portion (18) of the L-shaped groove (16) and rotated within the horizontal portion (20) of the L-shaped groove (16) such that the locking pin (26) is circumscribed by the housing (12) of the high pressure fuel pump (10) and cannot be withdrawn from within the horizontal portion (20) of the L-shaped groove (16).

3. The high pressure fuel pump (10) in accordance with Claim 1, wherein an end of the locking tool (22) comprises a conically shaped pointed edge (35), wherein the conically shaped pointed edge (35) of the locking tool (22) is adapted to compress against the indentation (28) that is defined in the control sleeve (30) that is secured to the plunger (32) of said high pressure fuel pump (10), the compression of the end of said locking tool (22) against the indentation (28) that is defined in said control sleeve (30) facilitates arresting a movement of said control sleeve (30) during an assembly of said high pressure fuel pump (10) within the engine.
, 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 locking tool for arresting a movement of a control sleeve during an assembly of the high pressure fuel pump within an engine.

Background of the invention
[0002] JP 3237224 A2 describes advancing the injection timing on start by installing a transmission quantity correcting mechanism in a power transmission system ranging from a speed adjusting lever to the output part of an adjustment operating tool and operating the transmission quantity correcting mechanism, on the basis of the starting operation of an engine. A fuel injection high pressure fuel pump changes the pre-stroke by vertically moving a control sleeve for a plunger through a control rod by a fuel injection timing adjustment operating tool. Further, the fuel injection quantity is adjusted by turning the plunger through a control rack by a governor lever which slidingly moves according to the number of engine revolution. An input arm fixed at the input edge part of the operating tool is connected with an adjusting lever through a connecting rod. In this case, a transmission quantity correcting mechanism which shortens the total length of the connecting rod through the electric conduction of an electromagnet through a starting circuit on cold start and adjusts the operating tool to the advance angle side is installed at the intermediate part of the connecting rod.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a high pressure fuel pump illustrating a locking tool for arresting movement of a control sleeve during an assembly of the high pressure fuel pump within an engine in one embodiment of the invention.

Detailed description of the embodiments
[0004] A high pressure fuel pump 10 is described. The high pressure fuel pump 10 comprises a housing 12, and a stepped groove 14 defined in the housing 12. The stepped groove 14 is adapted to extend from a top of the housing 12 to a bottom of the housing 12. An L-shaped groove 16 is defined within the stepped groove 14. A vertical portion 18 of the L-shaped groove 16 is adapted to originate from the top of the housing 12 and extends partially along a length of the stepped groove 14. A horizontal portion 20 of the L-shaped groove 16 is adapted to extend from the vertical portion 18 of the L-shaped groove 16 that is proximate to the top of the housing 12 and culminates at an end of a width of the stepped groove 14. A locking tool 22 comprising a step shaped portion 24 and a locking pin 26 extends radially outwardly from the locking tool 22. The step shaped portion 24 of the locking tool 22 is inserted and aligned with the stepped groove 14 that is defined in the housing 12. An end of the locking tool 22 is adapted to compress against an indentation 28 that is defined in a control sleeve 30 that is secured to a plunger 32 of the high pressure fuel pump 10. The compression of the end of the locking tool 22 against the indentation 28 that is defined in the control sleeve 30 facilitates arresting a movement of the control sleeve 30 during an assembly of the high pressure fuel pump 10 within an engine.

[0005] Figure 1 illustrates a high pressure fuel pump 10 illustrating a locking tool 22 for arresting a movement of a control sleeve 30 during an assembly of the high pressure fuel pump 10 within an engine in one embodiment of the invention. The high pressure fuel pump 10 comprises a housing 12 that houses a barrel and a plunger 32. A stepped groove 14 is defined in the housing 12. More specifically, in an exemplary embodiment, the stepped groove 14 is defined in an inner sidewall of the housing 12, and is adapted to extend from a top of the housing 12 to a bottom of the housing 12. The stepped groove 14 comprises a step shaped profile that has a first portion 40 of a larger diameter that extends from the top of the housing 12 to a displacement partially along the inner sidewall of the housing 12. The stepped groove 14 comprises a second portion 50 of a smaller diameter that is formed with the first portion 40 of the larger diameter and extends from an end of the first portion 40 of the larger diameter to the bottom of the housing 12. In an exemplary embodiment, a depth of the stepped groove 14 is equal to a radius of the locking tool 22. In an alternate exemplary embodiment, a depth of the stepped groove 14 is equal to any user defined depth that allows the locking tool 22 to fit snugly within the stepped groove 14. The locking tool 22 comprises a step shaped portion 24 of the first portion 42 having a larger diameter and smaller portion 52 having a smaller diameter that extends longitudinally from the first portion 40 and culminates in a conically shaped tip portion 35. In addition, the locking pin 26 constitutes an integral portion of the locking tool 22 and extends radially and outwardly from the first portion 42 of the locking tool 22.

[0006] In an exemplary embodiment, an L-shaped groove 16 is defined within the first portion 40 of the stepped groove 14. In an exemplary embodiment, a vertical portion 18 of the L-shaped groove 16 is adapted to originate from the top of the housing 12 and extends partially along a length of the first portion 40 of the stepped groove 14. A horizontal portion 20 of the L-shaped groove 16 is adapted to extend horizontally from a termination of the vertical portion 18 of the L-shaped groove 16 and culminates at an end of a width of the first portion 40 of the stepped groove 14. In an exemplary embodiment, a depth of the L-shaped groove 16 is user defined based on a user specific application. In an alternate exemplary embodiment, a depth of the L-shaped groove 16 is equal to a width of a locking pin 26 that is defined in the locking tool 22 to ensure that the locking pin 26 that is defined in the locking tool 22 fits snugly within the L-shaped groove 16 during assembly of the locking tool 22 within the stepped groove 14.

[0007] In an exemplary embodiment, the locking tool 22 is positioned snugly within the stepped groove 14 that is defined in the housing 12 of the high pressure fuel pump 10. More specifically, the locking tool 22 comprises a step shaped portion 24 of the first portion 42 having a larger diameter and smaller portion 52 having a smaller diameter that extends longitudinally from the first portion 40 and culminates in a conically shaped tip portion 35. In addition, the locking pin 26 constitutes an integral portion of the locking tool 22 and extends radially and outwardly from the longitudinal length of the locking tool 22. In an alternate exemplary embodiment, the locking pin 26 may be secured to the locking tool 22 via any mechanical fastening means that is known in the art.

[0008] In an exemplary embodiment, the step shaped portion 24 of the locking tool 22 is inserted and aligned with the stepped groove 14 that is defined in the housing 12. Therefore, the intersection of the first portion 42 having a larger diameter and the second portion 52 having a smaller diameter of the locking tool 22 is aligned with the intersection of the larger diameter 40 and the smaller diameter 50 of the stepped groove 14. An end of the locking tool 22 which comprises a conically shaped tip portion 35 is adapted to compress against an indentation 28 that is defined in a control sleeve 30 that is secured to a plunger 32 of the high pressure fuel pump 10. More specifically, when the locking tool 22 is positioned within the stepped groove 14, the end of the locking tool 22 which comprises the conically shaped tip portion 35 compresses against the indentation 28 that is defined in the control sleeve 30 that is secured to the plunger 32 of the high pressure fuel pump 10. The compression of the end of the conically shaped tip portion 35 of the locking tool 22 against the indentation 28 that is defined in the control sleeve 30 facilitates arresting a movement of the control sleeve 30 during an assembly of the high pressure fuel pump 10 within an engine. More specifically, the compression of the end of the conically shaped tip portion 35 of the locking tool 22 against the indentation 28 that is defined in the control sleeve 30 prevents the control sleeve 30 from translating axially in consequence to a force imparted by a control rod (not shown) that is secured to the control sleeve 30.

[0009] In an exemplary embodiment, the locking pin 26 that extends radially outwardly from the locking tool 22 is translated within the vertical portion of the L-shaped groove 16. When the locking pin 26 translated towards the bottom of the L-shaped groove 16, the locking pin 26 is rotated within the horizontal portion 20 of the L-shaped groove 16 such that the locking pin 26 is circumscribed by the housing 12 and is securely positioned within the horizontal portion 20 of the L-shaped groove 16 of the high pressure fuel pump 10. More specifically, when the locking pin 26 is rotated within the horizontal portion 20 of the L-shaped groove 16 such that the locking pin 26 is circumscribed by the housing 12 and is securely positioned within the horizontal portion 20 of the L-shaped groove 16 of the high pressure fuel pump 10, the locking pin 26 is secured within the horizontal portion 20 of the L-shaped groove 16. Therefore, the locking pin 26 is prevented from being withdrawn from within the horizontal portion 20 of the L-shaped groove 16. When it is required to withdraw the locking tool 22 from the housing 12 of the high pressure fuel pump 10, the locking tool 22 is rotated such that the locking pin 26 that is secured to the locking tool 22 is rotated from within the horizontal portion 20 of the L-shaped groove 16. Once the locking tool 22 is released from within the horizontal portion 20 of the L-shaped groove 16, the locking tool 22 may be withdrawn from within the vertical portion 18 of the L-shaped groove 16 and out of the high pressure fuel pump 10.

[0010] In an exemplary embodiment, an end of the locking tool 22 comprises a conically shaped tip portion that is integrally formed at the end of the smaller portion 52 of the locking tool 22. When the locking tool 22 is assembled on the sidewall of the housing 12 of the high pressure fuel pump 10, the conically shaped tip portion 35 of the locking tool 22 is adapted to compress against the indentation 28 that is defined in the control sleeve 30. More specifically, when the conically shaped tip portion 35 compresses against the indentation 28 that is defined in the control sleeve 30 that is secured to the plunger 32 of the high pressure fuel pump 10, the compressive forces imposed by the end of the locking tool 22 against the indentation 28 that is defined in the control sleeve 30 facilitates arresting a movement of the control sleeve 30 during an assembly of the high pressure fuel pump 10 within the engine. More specifically, due to the compressive force between the conically shaped tip portion 35 of the locking tool 22 against the indentation 28 that is defined in the control sleeve 30, the control sleeve 30 is locked in position. Therefore, the control sleeve 30 that is secured to the plunger 32 of the high pressure fuel pump 10 is prevented from being rotated from its equilibrium position, and is therefore held in position. The process is repeated for each assembly of each high pressure fuel pump 10 within the engine. Once each high pressure fuel pump 10 is assembled within the engine, each locking tool 22 may be withdrawn from each high pressure fuel pump 10. Therein, the governor may translate the control sleeve 30 of each high pressure fuel pump 10 to facilitate rotating the plunger 32 of each high pressure fuel pump 10 to the required angle of rotation to facilitate controlling a required quantity of pressurized fuel to be discharged from each high pressure fuel pump 10 to each fuel injector that is in flow communication with each high pressure fuel pump 10.

[0011] A working of the high pressure fuel pump 10 is described as an example. Each locking tool 22 is inserted within the stepped groove 14 via the vertical portion 18 of the L-shaped groove 16 during the assembly of the high pressure fuel pump 10 within the engine. Therein, the locking pin 26 that is secured to the locking tool 22 is rotated within the horizontal portion 20 of the L-shaped groove 16. The rotation of the locking pin 26 within the horizontal portion 20 of the L-shaped groove 16 facilitates securing the locking pin 26 of the locking tool 22 within the horizontal portion 20 of the L-shaped groove 16. Therefore, the locking tool 22 is secured within the housing 12 of the high pressure fuel pump 10. The conically shaped tip portion 35 of the locking tool 22 is adapted to compress against the indentation 28 that is defined on the control sleeve 30 that is secured to the plunger 32 of the high pressure fuel pump 10. Due to the compression of the conically shaped tip portion 35 of the locking tool 22 against the indentation 28 that is defined on the control sleeve 30, the control sleeve 30 is adapted to be prevented from being rotated. Therefore, the plunger 32 that is secured to the control sleeve 30 is prevented from being rotated within the high pressure fuel pump 10. The high pressure fuel pump 10 may now be safely positioned within the engine and secured thereto. After the high pressure fuel pump 10 is safely secured within the engine, the locking tool 22 may be rotated such that the locking pin 26 that is secured to the locking tool 22 is rotated within the horizontal portion of the L-shaped groove 16. The locking tool 22 may therein be withdrawn from the vertical portion 18 of the L-shaped groove 16. After the locking tool 22 is completely withdrawn from the stepped groove 14 that is defined within the sidewall of the high pressure fuel pump 10, the high pressure fuel pump 10 may be operated. More specifically, the governor of the high pressure fuel pump 10 translates a control rod (not shown), and hence controls the degree of rotation of the plunger 32. The rotation of the plunger 32 to the required degree of rotation facilitates controlling a degree of rotation of the helix groove, and hence the quantity of pressurized fuel that is delivered from the high pressure fuel pump 10 to the fuel injector.

[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.