Claims:We Claim:
1. A fuel filter (102) for an internal combustion engine comprising an inlet (201) for entry of low pressure fuel and an outlet (203) for exit of low pressure , the said outlet (203) separated from the inlet (201) by a barrier (202), characterized in the fuel filter (102):
a metal strainer (205);
a magnet (204) placed at the operative bottom of the fuel filter (102) and in proximity of the metal strainer.

2. The fuel filter (102) for an internal combustion engine as claimed in claim 1, where the metal strainer (205) is placed in either the proximity of the outlet (203) or the inlet (201) of the fuel filter (102).

3. The fuel filter (102) for an internal combustion engine as claimed in claim 1, wherein a contaminant detection sensor (206) is provided in said fuel filter.

4. The fuel filter (102) for an internal combustion engine as claimed in 1 where the outlet (203) of the fuel filter (102) has a pressure sensor (207).

5. A fuel injection system for an internal combustion engine comprising a High pressure fuel pump (104), a metering unit (103) and at least a low pressure fuel pump (101), characterized in the fuel injection system, a fuel filter (102) comprising:
An inlet (201) for entry of low pressure fuel from the fuel pump;
An outlet (203) for exit of low pressure fuel, the said outlet (203) separated from the inlet (201) by a barrier (202);
a metal strainer (205);
a magnet (204) placed at the operative bottom of the fuel filter (102) and in the proximity of the metal strainer.
6. The fuel injection system for an internal combustion engine as claimed in claim 5, where the fuel filter (102) is placed downstream from the low pressure fuel pump (101) and upstream from the metering unit (103).

7. The fuel injection system for an internal combustion engine as claimed in claim 5, where the metal strainer (205) is placed in either the proximity of the outlet (203) or the inlet (203) of the fuel filter (102).

8. The fuel injection system for an internal combustion engine as claimed in claim 5, where the fuel filter (102) wherein a contaminant detection sensor (206) is provided in the fuel filter.

9. The fuel injection system for an internal combustion engine as claimed in claim 5, where the outlet (203) of the fuel filter (102) has a pressure sensor (207).
, 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] The present disclosure relates to a fuel filter for an internal combustion engine.

Background of the invention
[0002] In an internal combustion engine a low pressure fuel pump supplies low pressure fuel downstream to other components for example a metering unit. The metering unit controls the amount of fuel to be supplied to the high pressure fuel pump. Conventional fuel filters or an integrated water and dust separator is installed in low pressure fuel pumps to remove dust and water impurities from the fuel. The fuel at low pressure also comprises various unwanted metallic impurities.

[0003] Patent Application US5517975A discloses a fuel purifying device for use in an internal combustion engine. Also disclosed is a method of purifying fuel in a fuel stream as it flows from a fuel tank to a vehicle engine, the fuel includes metallic impurities. The device and method uses electrostatic induction field across the fuel stream so as to cause molecules forming the fuel to break up and the dissolved oxygen content in the fuel stream to increase, which in turn causes the metallic impurities in the fuel stream to form colloidal masses with the dissolved oxygen.

Brief description of the accompanying drawings
[0004] An embodiment of the invention is described with reference to the following accompanying drawings:
[0005] Fig. 1 illustrates a fuel injection system for an internal combustion engine comprising a fuel filter, a High Pressure Fuel Pump, a metering unit , at least a low pressure fuel pump; and
[0006] Fig. 2 illustrates a fuel filter for an internal combustion engine.

Detailed description of the drawings

[0007] Figure 1 illustrates a fuel injection system for an internal combustion engine. It comprises a high pressure fuel pump (104), a metering unit (103), a low pressure fuel pump (101), and at least a fuel filter (102). The low pressure fuel pump (101) supplies fuel from the fuel tank upstream to the other components. Before the fuel is supplied to the metering unit (103), it is processed by an integrated water and dust separator (107). It is then supplied to the fuel filter (102). The fuel filter (102) removes the metallic impurities from the fuel and supplies it to the metering unit (103). The metering unit (103) then supplies the fuel to the high pressure fuel pump (104). The high pressure fuel pump (104) convert the low pressure fuel into high pressure fuel and supplies it to the high pressure fuel injection system. In an embodiment the high pressure fuel injection system comprises a common rail (105) and injectors (106).

[0008] Figure 2 illustrates a fuel filter (102) for an internal combustion engine. It comprises an inlet (201) for entry of low pressure fuel and an outlet (203) for exit of low pressure fuel. The said outlet (203) is separated from the inlet (201) by a barrier (202), which makes the fuel travel through a U-shaped opening at the bottom. The fuel filter (102) also comprises a metal strainer (205) and a magnet (204) placed at the operative bottom of the fuel filter (102) and in proximity of the metal strainer. In an embodiment the metal strainer (205) is placed in in proximity of the outlet (203) of the fuel filter (102). In another embodiment of the fuel filter the strainer is in proximity of the inlet (201).The fuel filter (102) for an internal combustion engine further comprises a contaminant detection sensor (206). In another embodiment of the present invention the contaminant detection sensor (206) is an LED sensor placed near the operative bottom of the fuel filter (102). The outlet (203) of the fuel filter (102) has a pressure sensor (207).

[0009] The fuel filter (102) for an internal combustion engine is placed downstream from the low pressure fuel pump (101) and upstream from the metering unit (103). The low pressure fuel pump (101) supplies fuel upstream to other components. Before the fuel is supplied to the metering unit (103), it is processed by an integrated water and dust separator (107). The integrated water and dust separator (107) remove water and dust contaminants from the low pressure fuel. It is then supplied to the fuel filter (102).

[0010] The fuel filter (102) diverts the flow of low pressure fuel via an inlet (201) to an operative bottom of the fuel filter (102) through a U-shaped opening. The fuel travelling via the inlet (201) reaches an operative bottom of the fuel filter (102), where the magnet (204) traps the magnetic contaminants of the fuel. The fuel then travels through the metal strainer (205) that traps the other non-magnetic metallic contaminants of the fuel. The fuel exits the fuel filter (102) via the outlet (203). In an embodiment of the present invention as discussed above a contaminant detection sensor (206) which is an LED sensor measures the amount of metallic contaminants trapped by the magnet (204) and the strainer. A pressure sensor (207) provided on the outlet (203) of the fuel filter (102) measures of the pressure of the fuel exiting the fuel filter (102). When the amount of contaminants trapped by the magnet (204) and strainer clogs the intersection path between the inlet (201) and outlet (203), the pressure in the outlet (203) reduces below a pre-defined threshold value. The reduction in pressure gives information to the user of the vehicle to clean the fuel filter (102).

[0011] The clean fuel, free from the metallic contaminants is supplied by the fuel filter (102) to the metering unit (103). The metering controls the amount of fuel supplied to the high pressure fuel pump (104). The high pressure fuel pump (104) then pressurizes this low pressure fuel to high pressure fuel, which is free from metal contaminants and supplies it to the high pressure fuel injection system. In an embodiment of the present invention as discussed above, the high pressure fuel injection system comprises a common rail (105) and an injector (106). The common rail (105) is a high pressure reservoir for fuel before it is supplied to the injector (106).
Another embodiment of the system is where the fuel filter is between the tank and the conventional fuel filter. Another embodiment of the system where the components of the claimed fuel filter are in the conventional fuel filter.

[0012] This idea to develop to trap metallic contaminants of the fuel, before it enters into the metering unit (103) will increase the efficiency of high pressure fuel pumps and high pressure fuel injection systems in an internal combustion engine. This will also increase the performance of vehicles as quality issues like startability would be eliminated. Such a modification in the low pressure circuit with the addition of the fuel filter (102) is feasible as it can be easily removed & cleaned.

[0013] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the fuel filter (102) for an internal combustion engine are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.