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
an accumulator (19) comprising an inlet flow path (20), an outlet flow path (22), and a storage chamber (24) positioned between the fuel inlet supply path (12) and the first chamber (14), the inlet flow path (20) of said accumulator (19) in flow communication with the fuel inlet supply path (12) and adapted to receive fuel supplied from the fuel inlet supply path (12) and deliver the received fuel to the storage chamber (24), the outlet flow path (22) of said accumulator (19) in flow communication with the first chamber (14) of said fuel filter (10) and adapted to deliver fuel supplied from the storage chamber (24) to the first chamber (14).

2. The fuel filter (10) for a fuel injection system in accordance with Claim 1, further comprising a flip valve (26) in flow communication with the fuel inlet supply path (12) and positioned upstream from said accumulator (19), the flip valve (26) adapted to switch a flow of pressurized fuel from the fuel inlet supply path (12) directly to the first chamber (14) of said fuel filter (10) to the inlet flow path (20) of said accumulator (19).
3. The fuel filter (10) for a fuel injection system in accordance with Claim 2, wherein said flip valve (26) is adapted to switch a flow of pressurized fuel from the fuel inlet supply path (12) directly to the first chamber (14) of said fuel filter (10) to the inlet flow path (20) of said accumulator (19) when a level of fuel within a fuel tank decreases below a fuel capacity that is pre-determined by a user.

4. The fuel filter (10) for a fuel injection system in accordance with Claim 3, wherein said flip valve (26) is adapted to switch a flow of pressurized fuel from the fuel inlet supply path (12) to the inlet flow path (20) of said accumulator (19) directly to the first chamber (14) of said fuel filter (10) when the level of fuel within the fuel tank increases above a fuel capacity that is pre-determined by the user.

5. The fuel filter (10) for a fuel injection system in accordance with Claim 4, further comprising an engine control unit (26) in electronic communication with a fuel level controller and said flip valve (26), wherein the engine control unit (26) is adapted to control a position of said flip valve (26) to switch a flow of pressurized fuel from the fuel inlet supply path (12) directly to the first chamber (14) of said fuel filter (10) to the inlet flow path (20) of said accumulator (19) when a signal received by the engine control unit (26) from said fuel level controller is indicative that the fuel level within the fuel tank is below a fuel capacity that is pre-determined by the user.

6. The fuel filter (10) for a fuel injection system in accordance with Claim 5, wherein the engine control unit (26) is adapted to control a position of said flip valve (26) to switch a flow of pressurized fuel from the fuel inlet supply path (12) to the inlet flow path (20) of said accumulator (19) directly to the first chamber (14) of said fuel filter (10) when a signal received by the engine control unit (26) from said fuel level controller is indicative that the fuel level within the fuel tank is above a fuel capacity that is pre-determined by the user
, 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 fuel filter, and more specifically to a fuel filter for a fuel injection system with an accumulator integrated therein.

Background of the invention
[0002] MX 9602395 A1 describes a fuel feeding circuit, comprising a fuel tank, a fuel module having a level receiver inside the tank, fuel feeding piping joined to the module fuel outlet. A fuel filter is interbedded in the feeding piping. The fuel inlet collector comprises feeding piping, projects from respective electric injectors, and electric injectors which deliver fuel into respective cylinders of the motor. A pressure regulating device and a return piping are attached to both the pressure regulating device and the fuel module return inlet. The pressure regulating device is assembled away from the motor, especially at the fuel outlet, and is not heated by the motor heat.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic representation of a fuel filter for a fuel injection system comprising an accumulator integrated therein in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a fuel filter 10 for a fuel injection system. The fuel filter 10 comprises a fuel inlet supply path 12. A first chamber 14 is 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 is adapted to filter pressurized fuel that flows through the first chamber 14 and delivers the pressurized fuel to the second chamber 18. An accumulator 19 comprising an inlet flow path 20, an outlet flow path 22, and a storage chamber 24 is positioned between the fuel inlet supply path 12 and the first chamber 14. The inlet flow path 20 of the accumulator 19 is in flow communication with the fuel inlet supply path 12 and is adapted to receive fuel supplied from the fuel inlet supply path 12 and deliver the received fuel to the storage chamber 24. The outlet flow path 22 of the accumulator 19 is in flow communication with the first chamber 14 and is adapted to deliver fuel supplied from the storage chamber 24 to the first chamber 14.

[0005] Figure 1 illustrates a fuel filter 10 for a fuel injection system. The fuel filter 10 comprises a fuel inlet supply path 12 that is in flow communication with a fuel tank of a vehicle and receives fuel that is supplied from the fuel tank of the vehicle. In an exemplary embodiment, a first chamber 14 of the fuel filter 10 is in flow communication with the fuel inlet supply path 12 and is adapted to receive fuel from the fuel inlet supply path 12 that is supplied from the fuel tank. A porous membrane 16 is positioned between the first chamber 14 and a second chamber 18 of the fuel filter 10, and is adapted to filter the fuel that flows from the first chamber 14 towards the second chamber 18. The porous membrane 16 is adapted to filter the pressurized fuel that flows through the first chamber 14 and deliver the pressurized fuel to the second chamber 18. From the second chamber 18, the pressurized fuel is delivered to an inlet of a high pressure fuel pump for pressurization and delivery to an engine cylinder.

[0006] In an exemplary embodiment, an accumulator 19 comprises an inlet flow path 20, an outlet flow path 22, and a storage chamber 24 that is positioned between the fuel inlet supply path 12 and the first chamber 14 of the fuel filter 10. The inlet flow path 20 of the accumulator 19 is in flow communication with the fuel inlet supply path 12 and is adapted to receive fuel that is supplied from the fuel tank of the vehicle via the fuel inlet supply path 12 and deliver the received fuel to the storage chamber 24 of the accumulator 19. The capacity of the storage chamber 24 of the accumulator 19 is such that the accumulator 19 is adapted to store a substantial quantity of the fuel (normally between 2 – 3 liters) that is delivered from the fuel inlet supply path 12 from the fuel tank of the vehicle, and supply the stored fuel to the first chamber 14 of the fuel filter 10 when the fuel tank of the vehicle is not able to deliver fuel directly to the first chamber 14 of the fuel filter 10 as a consequence of the level of fuel within the fuel tank decreasing to a low level. More specifically, the outlet flow path 22 of the accumulator 19 is in flow communication with the first chamber 14 of the fuel filter 10, and is adapted to deliver fuel that is supplied from the storage chamber 24 of the accumulator 19 to the first chamber 14 of the fuel filter 10 when the level of fuel within the fuel tank is lower than a threshold fuel level that is pre-determined by a user.

[0007] In an exemplary embodiment, a flip valve 26 is in flow communication with the fuel inlet supply path 12. More specifically, the flip valve 26 that is in flow communication with the fuel inlet supply path 12 is located upstream from the accumulator 19 and is adapted to redirect a flow of pressurized fuel that flows from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10 to the inlet flow path 20 of the accumulator 19 by bypassing the flow of pressurized fuel from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10. More specifically, the flip valve 26 is adapted to switch a flow of pressurized fuel from the fuel inlet supply path 12 directly to the first chamber 14 of the fuel filter 10 to the inlet flow path 20 of the accumulator 19 when a level of fuel within the fuel tank decreases below a fuel capacity that is pre-determined by the user. Therefore, when the level of fuel within the fuel tank decreases below the fuel capacity that is pre-determined by the user, the flip valve 26 is adapted to redirect a flow of pressurized fuel that flows from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10 to the inlet flow path 20 of the accumulator 19, and into the storage chamber 24 of the accumulator 19 for storage therein.

[0008] Conversely, the flip valve 26 is adapted to switch a flow of pressurized fuel from the fuel inlet supply path 12 to the inlet flow path 20 of the accumulator 19 directly to the first chamber 14 of the fuel filter 10 by bypassing the inlet flow path 20 of the accumulator 19 when the level of fuel within the fuel tank increases above a fuel capacity that is pre-determined by the user. Therefore, when the level of fuel within the fuel tank increases above the fuel capacity that is pre-determined by the user, the flip valve 26 is adapted to redirect a flow of pressurized fuel that flows from the fuel inlet supply path 12 directly into the inlet flow path 20 of the accumulator 19 to the first chamber 14 of the fuel filter 10.

[0009] In an exemplary embodiment, an engine control unit 26 is in electronic communication with a fuel level controller of the fuel tank and the flip valve 26 that is in flow communication with the fuel inlet supply path 12. The engine control unit 26 is adapted to control a position of the flip valve 26 to switch a flow of pressurized fuel from the fuel inlet supply path 12 directly to the first chamber 14 of the fuel filter 10 to the inlet flow path 20 of the accumulator 19 when a signal received by the engine control unit 26 from the fuel level controller is indicative that the level of fuel within the fuel tank of the vehicle is below a threshold fuel capacity that is pre-determined by the user. Conversely, the engine control unit 26 is adapted to control a position of the flip valve 26 to switch the flow of pressurized fuel from the fuel inlet supply path 12 to the inlet flow path 20 of the accumulator 19 directly to the first chamber 14 of the fuel filter 10 by bypassing the inlet flow path 20 of the accumulator 19 when a signal received by the engine control unit 26 from the fuel level controller is indicative that the level of fuel within the fuel tank is above a fuel capacity that is pre-determined by the user.

[0010] A working of the fuel filter 10 with the accumulator 19 integrated therein is now described as an example. When pressurized fuel from the fuel tank is channeled into the fuel inlet supply path 12, the pressurized fuel is permitted to flow from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10. From the first chamber 14 of the fuel filter 10, the pressurized fuel is filtered by means of the porous membrane 16 and delivered to the second chamber 18 of the fuel filter 10. From the second chamber 18 of the fuel filter 10, the pressurized fuel is delivered to an inlet of a high-pressure fuel pump for further pressurization and delivery to an engine. When a volume of the pressurized fuel within the fuel tank of the vehicle decreases below a threshold volume that is pre-determined by a user (say 15 liters), the engine control unit 26 operates the flip valve 26 that is in flow communication with the fuel inlet supply path 12. More specifically, the engine control unit 26 operates the flip valve 26 to redirect a flow of pressurized fuel that flows from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10 to the inlet flow path 20 of the accumulator 19 and into the storage chamber 24 of the accumulator 19 for storage therein, by bypassing the flow of pressurized fuel from the fuel inlet supply path 12 directly into the first chamber 14 of the fuel filter 10. Therefore, when the volume of the fuel that is in the fuel tank is below the threshold level that is pre-determined by the user, the accumulator 19 acts as a buffer fuel storage and delivery device when it is not possible to maintain continuity of fuel flow from the fuel tank directly to the first chamber 14 of the fuel filter 10. From the accumulator 19, the pressurized fuel is permitted to flow directly into the first chamber 14 of the fuel filter 10 for further filtration and subsequent delivery to the high pressure fuel pump for pressurization.

[0011] Pressurized fuel from the fuel tank of the vehicle that flows into the accumulator 19 is delivered in two stages. The first stage of fuel flow is from the fuel tank of the vehicle into the accumulator 19 via the fuel inlet supply path 12 and via the inlet flow path 20 of the accumulator 19. The second stage of fuel flow is from the accumulator 19 into the first chamber 14 of the fuel filter 10 via the outlet flow path 22. The process of fuel delivery from the fuel tank of the vehicle into the accumulator 19 via the fuel inlet supply path 12 and via the inlet flow path 20 of the accumulator 19 continues unabated until the fuel tank of the vehicle is refilled with fresh fuel. Once the fuel tank of the vehicle is filled with fresh fuel above the threshold capacity that is defined by the user (say 15 liters), the engine control unit 26 operates the flip valve 26 that is in flow communication with the fuel inlet supply path 12. More specifically, the engine control unit 26 operates the flip valve 26 to redirect a flow of pressurized fuel that flows from the fuel inlet supply path 12 to the inlet flow path 20 of the accumulator 19 and into the storage chamber 24 of the accumulator 19 for storage therein directly into the first chamber 14 of the fuel filter 10, by bypassing the flow of pressurized fuel from the fuel inlet supply path 12 to the inlet flow path 20 of the accumulator 19. Therefore, the accumulator 19 facilitates storing fuel that is delivered from the fuel tank when a fuel capacity of the fuel tank is below a threshold volume that is pre-determined by the user. This ensures that when fuel is intermittently supplied from the fuel tank to the first chamber 14 of the fuel filter 10 such as during uphill / downhill driving conditions of the vehicle, the fuel that was routed from the fuel tank of the vehicle to the accumulator 19 is delivered continuously from the accumulator 19 to the first chamber 14 of the fuel filter 10. This ensures that a continuous flow of streamlined fuel is maintained to the first chamber 14 of the fuel filter 10 from the accumulator 19 during the entire driving cycle of the vehicle when the volume of fuel in the fuel tank decreases below the threshold volume that is pre-determined by the user. Once the fuel in the fuel tank is refilled and increased above the threshold volume that is pre-determined by the user, the flip valve 26 operated by the engine control unit 26 ensures that a continuous stream of fuel is delivered from the fuel tank of the vehicle to the first chamber 14 of the fuel filter 10.

[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.