Claims:We Claim

1. A fuel filter (10) for a fuel injection system, said fuel filter (10) comprising:
a fuel inlet supply path (12);
a first chamber (14) positioned below the fuel inlet supply path (12), the first chamber (14) adapted to receive fuel from the fuel inlet supply path (12);
a porous membrane (16) positioned between the first chamber (14) and a second chamber (18), the porous membrane (16) adapted to filter pressurized fuel that flows through the first chamber (14) and delivers the pressurized fuel to the second chamber (18); characterized in that
a valve element (20) positioned between the fuel inlet supply path (12) and the first chamber (14), the valve element (20) adapted to facilitate controlling a flow of pressurized fuel from the fuel inlet supply path (12) to the first chamber (14).

2. The fuel filter (10) for the fuel injection system in accordance with Claim 1 wherein the valve element (20) is a spring loaded valve element.

3. The fuel filter (10) for the fuel injection system in accordance with Claim 1 wherein the valve element (20) is one of a pneumatically actuated valve element, and a mechanically actuated valve element.
, Description:Field of the invention
[0001] This invention relates to a fuel filter and more specifically to a fuel filter for a fuel injection system.

Background of the invention
[0002] US 6019890 describes a fuel filter assembly that employs a hand primer and a disposable filter cartridge mounted to a header. The filter cartridge has a filter element which defines an interior chamber for receiving the filtered fuel. The hand primer includes a diaphragm which cooperates with the header to define a reservoir and a valve plate having a plurality of orifices and an axial opening for providing fluid communication between an exit passage of the header and the reservoir, and between the chamber and the reservoir respectively. A first check valve is mounted in the opening and a second check valve is mounted in an axial bore in the first check valve. The first and second check valves are moveable between an open position for allowing flow through the orifices of the valve plate and orifices in the first check valve respectively, and a closed position for preventing such flow. The filter assembly is primed by pushing the diaphragm downwards, creating a high pressure which moves the first check valve to the open position and the second check valve to the closed position, causing trapped air to be expelled through the orifices and the exit passage. Removing the downward force allows a spring to return to bias the diaphragm upwards, creating a low pressure which moves the first check valve to the closed position and the second check valve to the open position, and drawing fuel from the interior chamber.

Brief description of the accompanying drawings
[0003] Figure 1 illustrates a schematic representation of a single fuel filter for a fuel injection system.
[0004] Figure 2 illustrates a schematic representation of a dual fuel filter for the fuel injection system.

Detailed description of the embodiments

[0005] Figure 1 illustrates a fuel filter 10 for a fuel injection system. The fuel filter 10 comprises a fuel inlet supply path 12 and a first chamber 14 positioned below the fuel inlet supply path 12, the first chamber 14 adapted to receive fuel from the fuel inlet supply path 12. A porous membrane 16 is positioned between the first chamber 14 and a second chamber 18, the porous membrane 16 adapted to filter pressurized fuel that flows through the first chamber 14 and delivers the pressurized fuel to the second chamber 18. A valve element 20 is positioned between the fuel inlet supply path 12 and the first chamber 14, the valve element 20 adapted to facilitate controlling a flow of pressurized fuel from the fuel inlet supply path 12 to the first chamber 14.

[0006] The fuel filter 10 for the fuel injection system comprises a fuel inlet supply path 12 that is in flow communication with a source of fuel such as a fuel tank. A first chamber 14 is positioned below the fuel inlet supply path 12 and is in flow communication with the fuel inlet supply path 12. The fuel that is channeled through the fuel inlet supply path 12 is delivered to the first chamber 14. The first chamber 14 comprises an annular space that is circumferentially defined around a sidewall of the first chamber 14 such that the sidewall circumscribes the first chamber 14. A porous membrane 16 is positioned between the first chamber 14 and a second chamber 18. More specifically, the porous membrane 16 is circumferentially defined within the first chamber 14 and filters the fuel that is supplied to the first chamber 14 from the fuel inlet supply path 12. The filtered fuel that flows through the porous membrane 16 enters the second chamber 18. Therein, the filtered and pressurized fuel from the second chamber 18 is delivered to a high pressure fuel pump via a fuel outlet supply path 22.

[0007] A valve element 20 is positioned between the fuel inlet supply path 12 and the first chamber 14. In an exemplary embodiment, the valve element 20 is adapted to facilitate channeling pressurized fuel from the fuel inlet supply path 12 to the first chamber 14. More specifically, when pressurized fuel from the fuel inlet supply path 12 forces against the valve element 20, the valve element 20 opens about a hinged pivot, thereby allowing the pressurized fuel to flow into the first chamber 14. From the first chamber 14, the pressurized fuel is channeled to the second chamber 18 via the porous membrane 16 from where it is further delivered to the fuel outlet supply path 22. In an exemplary embodiment, the valve element 20 is a mechanical spring loaded valve element that is adapted to open about a hinged pivot to facilitate channeling pressurized fuel to the first chamber 14 from the fuel inlet supply path 12. In an alternate exemplary embodiment, the valve element 20 is a pressure actuated valve element that is actuated by means of pressurized air/fuel. In yet another alternate exemplary embodiment, the valve element 20 is an electrically actuated valve element.

[0008] Figure 2 illustrates a schematic representation of a duel fuel filter 100 for the fuel injection system. The dual fuel filter 100 for the fuel injection system comprises a second fuel filter 50 and the first fuel filter 10 that is in flow communication with the second fuel filter 50. The second fuel filter 50 comprises a fuel inlet supply path 52 that is in flow communication with the fuel outlet supply path 22 of the first fuel filter 10. A first chamber 54 is positioned below the fuel inlet supply path 52 and is in flow communication with the fuel inlet supply path 52. The fuel that is channeled through the fuel inlet supply path 52 is delivered to the first chamber 54. The first chamber 54 comprises an annular space that is circumferentially defined around a sidewall of the second chamber 54. A porous membrane 56 is positioned between the first chamber 54 and a second chamber 58. In the exemplary embodiment, the porous membrane 56 of the second fuel filter 50 has pores of a diameter that is smaller than that of the porous membrane 16 of the first fuel filter 10 to facilitate trapping particulate matter that has escaped through the porous membrane 16 of the first fuel filter 10. More specifically, the porous membrane 56 is circumferentially defined within the first chamber 54 and filters the fuel that is supplied to the first chamber 54 from the fuel inlet supply path 52. The filtered fuel that flows through the porous membrane 56 enters the second chamber 58. Therein, the filtered and pressurized fuel from the second chamber 58 is delivered to a high pressure fuel pump via a fuel outlet supply path 60.

[0009] A working of the fuel filter 10 for the fuel injection system is described as an example. Fuel is supplied to the fuel inlet supply path 12 from the fuel tank. From the fuel inlet supply path 12, the pressurized fuel is supplied to the first chamber 14 via the valve element 20. When the pressurized fuel acts on the valve element 20, the valve element 20 opens against a force of the spring member about a hinged pivot thereby opening the passageway from the fuel inlet supply path 12 to the first chamber 14. The fuel that is supplied to the first chamber 14 percolates through the porous membrane 16 and enters the second chamber 18. Therein, the filtered and pressurized fuel from the second chamber 18 is delivered to the fuel outlet supply path 22. In an exemplary embodiment, the fuel from the fuel outlet supply path 22 is supplied to the high pressure fuel pump for further pressurization. In an alternate exemplary embodiment, the filtered and pressurized fuel from the fuel outlet supply path 22 is delivered to the fuel inlet supply path 52 of the second fuel filter 50. From the fuel inlet supply path 52, the pressurized fuel is supplied to the first chamber 54 of the second fuel filter 50. The fuel that is supplied to the first chamber 54 percolates through the porous membrane 56 and enters the second chamber 58. Therein, the filtered and pressurized fuel from the second chamber 58 is delivered to the fuel outlet supply path 60 of the second fuel filter 50. In the exemplary embodiment, the fuel from the fuel outlet supply path 60 of the second filter 50 is supplied to the high pressure fuel pump for further pressurization.

[0010] The advantage of the valve element 20 being positioned below the fuel inlet supply path 12 allows the fuel that is supplied through the fuel inlet supply path 12 to be channeled quickly through the fuel filter 10 and delivered to the fuel outlet supply path 22. As a consequence, during engine starting conditions, fuel is quickly and efficiently delivered from the fuel inlet supply path 12 to the fuel outlet supply path 22 through the fuel filter 10. The presence of the valve element 20 allows for fuel to be quickly delivered from the fuel outlet supply path 22 to the high pressure fuel pump for further pressurization thus allowing the engine to start more effeciently.

[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 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 scope of the claims.