Claims:We Claim:
1. An overflow valve 10 of a fuel control unit 12, said overflow valve 10 comprising:
a housing 14, said housing 14 having an inlet and an outlet;
a screw plug 16 positioned within said housing 14;
a spring 18 positioned within said housing 14, a first end of said spring 18 positioned against said screw plug 16; characterized in that
a reciprocating member 20 positioned against a second end of said spring 18 and at least a part of said reciprocating member 20 extending into said inlet and parallel to a flow direction in a manner such that flow of fuel from said inlet to said outlet is laminar, and wherein said reciprocating member 20 is adapted to translate against a force of said spring 18.

2. The overflow valve 10 for the fuel control unit 12 in accordance with Claim 1 wherein said reciprocating member 20 comprises a shank portion 26 and a flanged portion 28 defined at an end of said shank portion 26, said flanged portion 28 having a flat surface and seals said reciprocating member against said housing 14.

3. The overflow valve 10 for the fuel control unit 12 in accordance with Claim 2 wherein the flat surface of said flanged portion 28 is flush against a flat surface of a housing 30 of said fuel control unit 12 to facilitate sealing said overflow valve 10 of said fuel control unit 12.

4. The overflow valve 10 for the fuel control unit 12 in accordance with Claim 3 wherein said housing 30 of said fuel control unit 12 is hard coated at the flat surface of said housing 30 of said fuel control unit 12 and the flat surface of said flanged portion 28 of said fuel control unit 12 to prevent a translation of said shank portion 26 of said reciprocating member 20 from eroding said housing 30 of said fuel control unit 12.

5. A fuel control unit 12, said fuel control unit 12 comprising:
a fuel inlet path 22;
a fuel outlet path 24;
an overflow valve 10 positioned in a fuel passage defined between said fuel inlet path 22 and said fuel outlet path 24, said overflow valve 10 comprising:
a housing 14;
a screw plug 16 positioned within said housing 14;
a spring 18 positioned within said housing 14, a first end of said spring 18 positioned against said screw plug 16; characterized in that
a reciprocating member 20 positioned against a second end of said spring 18 and at least a part of said reciprocating member 20 extending into an inlet of said overflow valve 10 in a manner such that flow of fuel from said inlet to an outlet of said overflow valve 10 is laminar in nature, and wherein said reciprocating member 20 is adapted to translate against a force of said spring 18.

6. The fuel control unit 12 in accordance with Claim 5 wherein said reciprocating member 20 comprises a shank portion 26 and a flanged portion 28 defined at an end of said shank portion 26, said flanged portion 28 having a flat surface and seals said reciprocating member against said housing 14.

7. The fuel control unit 12 in accordance with Claim 6 wherein the flat surface of said flanged portion 28 is flush against a flat surface of a housing 30 of said fuel control unit 12 to facilitate sealing said overflow valve 10 of said fuel control unit 12.

8. The fuel control unit 12 in accordance with Claim 6 wherein said housing 30 of said fuel control unit 12 is hard coated at the flat surface of said housing 30 of said fuel control unit 12 and the flat surface of said flanged portion 28 of said fuel control unit 12 to prevent a translation of said shank portion 26 of said reciprocating member 20 from eroding said housing 30 of said fuel control unit 12. , Description:Field of the invention
[0001] This invention relates to a fuel control unit and more particularly to an overflow valve used in the fuel control unit.

Background of the invention
[0002] The overflow valve used in a conventional fuel control unit uses a ball element for regulating pressure within the fuel control unit. The ball element reciprocates along a path against a force of a spring. The reciprocation of the ball element helps in directing fuel within a constricted space of the overflow valve. Finally the fuel is delivered to a high pressure fuel pump.
[0003] Indian Patent Application Number 3901/CHE/2013 describes an overflow valve in a fuel control unit. The overflow valve comprises a housing having an inlet, at least one outlet, and a plug disposed within the housing. The overflow valve is characterized in having a spring and a reciprocating member. The reciprocating member is located at the interface of the inlet and the outlet, and is coaxial with the inlet and the plug. The spring is located in the housing in a manner such that one end of the spring abuts the plug, and the other end of the spring is in contact with the reciprocating member.
[0004] The object of the invention is to maintain fuel supply at uniform pressure in the fuel control unit.

Brief description of the accompanying drawings
[0005] Figure 1 illustrates a fuel control unit that supplies fuel to a high pressure fuel pump;
[0006] Figure 2 illustrates a side view of the reciprocating member 20 of the fuel control unit; and
[0007] Figure 3 illustrates the reciprocating member of the fuel control unit in one embodiment of the invention.

Detailed description of the invention
[0008] Figure 1 illustrates a fuel control unit that supplies fuel to a high pressure fuel pump. The overflow valve 10 comprises a housing 14, the housing 14 having an inlet and an outlet. A screw plug 16 is positioned within the housing 14. A spring 18 is positioned within the housing 14, a first end of the spring 18 positioned against the screw plug 16. A reciprocating member 20 is positioned against a second end of the spring 18 and at least a part of the reciprocating member 20 extends into the inlet in a manner such that flow of fuel from the inlet to the outlet is laminar, and wherein the reciprocating member 20 is adapted to translate against a force of the spring 18.
[0009] In addition, a fuel control unit 12 is described. The fuel control unit 12 comprises a fuel inlet path 22 and a fuel outlet path 24. An overflow valve 10 is positioned in a fuel passage defined between the fuel inlet path 22 and the fuel outlet path 24, the overflow valve 10 comprising a housing 14 and a screw plug 16 positioned within the housing 14. A spring 18 is positioned within the housing 14, a first end of the spring 18 positioned against the screw plug 16. A reciprocating member 20 is positioned against a second end of the spring 18 and at least a part of the reciprocating member 20 extending into the inlet in a manner such that flow of fuel from the inlet to the outlet is laminar, and wherein the reciprocating member 20 is adapted to translate against a force of the spring 18.
[0010] The fuel control unit 12 supplies fuel to a high pressure fuel pump. The fuel control unit 12 comprises a housing 14 and a fuel inlet path 22 coupled to the housing 14. The fuel inlet path 22 supplies fuel to the fuel control unit 12. An overflow valve 10 is positioned within the fuel control unit 12 and facilitates channeling fuel of a pressure that is above a threshold fuel pressure out of the fuel control unit 12. The fuel control unit 12 comprises a fuel outlet path 24. The fuel outlet path 24 channels fuel out of the fuel control unit 12 when the overflow valve 10 is operational in order to reduce a pressure of fuel that is delivered from the fuel control unit 12 to the high pressure fuel pump.

[0011] A spring 18 is positioned within a passage defined within the fuel control unit 12. A first end of the spring 18 is positioned against a screw plug 16 which facilitates sealing the fuel control unit 12. A second end of the spring 18 is positioned against a reciprocating member 20. Pressurized fuel of a pressure that is above a threshold fuel pressure flowing through the fuel control unit 12 causes the reciprocating member 20 to be displaced against a force of the spring 18, causing the pressurized fuel to be channeled out of the fuel control unit 12 via the fuel outlet path 24.
[0012] Figure 2 illustrates a side view of the reciprocating member 20 of the fuel control unit 12. The reciprocating member 20 comprises a shank portion 26. The shank portion 26 of the reciprocating member 20 is positioned in the fuel passage between the fuel inlet path 22 and the fuel outlet path 24 such that the maximum travel of the reciprocating member 20 within the housing 30 is provided. The shank portion 26 prevents fuel that is channeled through the fuel inlet path 22 from flowing past and out of the fuel control unit 12 via the fuel outlet path 24. The reciprocating member 20 comprises a flanged portion 28 that is adjacent to the shank portion 26. The flanged portion 28 of the reciprocating member 20 forms a sealing contact with the housing 30 of the fuel control unit 12 to prevent fuel from flowing through the fuel outlet path 24. More specifically, a flat surface of the flanged portion 28 of the reciprocating member 20 is flush against a flat surface of the housing 30 of the fuel control unit 12 to facilitate sealing the overflow valve 10 of the fuel control unit 12.
[0013] In an embodiment, the shank portion 26 of the fuel control unit 12 comprises a plurality of flutes that are each separated by a groove. When the shank portion 26 is inserted within the fuel passage defined between the fuel inlet path 22 and the fuel outlet path 24, each of the plurality of flutes of the fuel control unit 12 facilitates guiding the fuel from the fuel passage to the fuel outlet path 24 of the fuel control unit 12. In addition, the fuel control unit 12 is hard coated on the housing 30 of the fuel control unit 12. The fuel control unit 12 is hard coated on the housing 30 of the fuel control unit 12 to prevent erosion of the housing 30 of the fuel control unit 12 when the shank portion 26 of the reciprocating member 20 translates. The shank portion 26 of the reciprocating member 20 facilitates sealing the housing 30 to avoid turbulence. Moreover, due to the elimination of turbulence, the noise generated due to turbulence may be eliminated in the fuel control unit 12.
[0014] Figure 3 illustrates a reciprocating member 20 of the fuel control unit 12. The shank portion 26 of the fuel control unit 12 comprises a plurality of flutes that are each separated by a groove. Each of the plurality of flutes 30 facilitate guiding the reciprocating member 20 of the fuel control unit 12 within the fuel passage defined between the fuel inlet path 22 and the fuel outlet path 24. A plurality of grooves 32 are defined between the plurality of flutes 30 and are adapted to channel fuel through the reciprocating member 20 of the fuel control unit 12 to the fuel outlet path 24. The reciprocating member 20 of the fuel control unit 12 comprises a shank portion 26. A flanged portion 28 is formed at an end of the shank portion 26 and facilitates sealing the reciprocating member 20 of the fuel control unit 12 against the housing 30 of the fuel control unit 12. When the reciprocating member 20 of the fuel control unit 12 is displaced against the spring 18 when pressurized fuel above a threshold fuel pressure is channeled into the fuel control unit 12, the flanged portion 28 is not in sealing arrangement with the housing 30 of the fuel control unit 12. Therein, pressurized fuel flows through the fuel inlet path 22, through the fuel passage, and out of the fuel outlet path 24 via the plurality of grooves 32 that are defined in the reciprocating member 20.
[0015] A working of the overflow valve 10 in a fuel control unit 12 is described as an example. Fuel flows into the overflow valve 10 via the fuel inlet path 22. From the fuel inlet path 22, the pressurized fuel flows through the fuel passage. If the fuel flowing into the fuel passage is above a threshold fuel pressure, the reciprocating member 20 is displaced against a resistance of the spring 18. Pressurized fuel flows through each of the plurality of grooves 32 that are adjacent each of the plurality of flutes 30. The pressurized fuel that flows through each of the plurality of grooves 32 is channeled out of the fuel control unit 12 via the fuel outlet path 24. After the pressure of fuel entering the fuel control unit 12 via the fuel inlet path 22 decreases below the threshold fuel pressure, the reciprocating member 20 is displaced to its original position due to the restoring force of the spring 18 acting on the reciprocating member 20. The reciprocating member 20 seals the fuel passage, thereby preventing any further fuel from flowing out of the fuel control unit 12 via the fuel outlet path 24. The present invention employing the reciprocating member 20 from channeling fuel to the fuel outlet path 24 is robust and therefore does not vibrate, thereby eliminating noise that is generated in the fuel control unit 12.
[0016] 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 leverage and dimensions of various levers are envisaged and form a part of this invention. The scope of the invention is only limited by the claims.