Claims:CLAIMS 5
We Claim:
1. A dual fuel filter (12) for supplying fuel to a fuel injection system, said dual fuel filter (12) comprising:
- a main filter (14);
- an auxiliary filter (16) placed parallel to said main filter 10 (14);
characterized in that:
- a first pressure sensor (18) located in proximity to said main filter (14) and connected to said main filter (14), said first pressure sensor (18) adapted to sense pressure in said 15 main filter (14) ;
- a second pressure sensor (20) located in proximity to said auxiliary filter (16) and connected to said second pressure sensor (20), said second pressure sensor (20) adapted to sense pressure in said auxiliary filter (16); 20
- an inlet valve (22) positioned upstream to said main filter (14) and said auxiliary filter (16);
- an outlet valve (24) positioned downstream to said main filter (14) and said auxiliary filter (16).
2. The dual fuel filter (12) as claimed in claim 1, wherein said 25 outlet valve (24) is adapted to work in tandem with said inlet valve (22).
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3. The dual fuel filter (12) as claimed in claim 1, wherein said first 5 and second pressure sensors (18,20) and said inlet and outlet valves (22,24) are connected to a control unit (25).
4. The dual fuel filter (12) as claimed in claim 1, wherein said inlet valve (22) is a solenoid operation directional valve and said outlet valve (24) is a shutter valve. 10
5. The dual fuel filter (12) as claimed in claim 1, wherein said control unit (25) is adapted to close said inlet valve (22) and said outlet valve (24) for the main filter , upon detecting a clogging of said main filter when pressure difference from said first pressure sensor (18) of said main filter (14) is more than 15 a predefined value.
6. The dual fuel filter (12) as claimed in claim 1, wherein said
control unit (25) is adapted to close said inlet valve (22) and said outlet valve (24) for said auxiliary filter (16) , upon detecting a clogging of said auxiliary filter (16), when pressure 20 difference from said second pressure sensor (20) of said auxiliary filter (16) is more than said predefined value. , Description:Field of the invention 5
[0001] This invention relates to a dual fuel filter in a fuel injection pump.
Background of the invention
[0002] A vehicle fuel system typically has a fuel tank for holding a 10 supply of liquid fuel for delivery to an engine. Fuel filters in the fuel system removes contaminants such as dirt and water from the fuel before it reaches the engine. Fuel filters have been used in the fuel system at either the vacuum side or the pressure side of the fuel pump. In commercial vehicles and the passenger cars, the fuel filters 15 are changed at regular intervals. One common problem associated with changing filters is fuel spillage. The fuel lines and element are often under pressure. When the element is removed, the pressure is relieved and the fuel spills out. This can present a fire hazard as well as a waste cleanup problem. The clogged filter in the vehicle can cause 20 poor engine performance and allow undesirable amounts of contaminants that shortens engine life. The present invention provides a solution that an auto switching between two fuel filters in a vehicle by providing an auxiliary filter during emergencies.
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[0003] Prior art patent application US20110070053 discloses a 5 multiple fuel filter pump module that includes a module housing. The module housing is formed to include a pump housing and a dual fuel filter head portion. A fuel pump is positioned within the pump housing, and more than one detachable fuel filter assemblies are attached to the multiple fuel filter head portion. The module housing 10 can be attached to an engine housing.
Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the 15 description and illustrated in the accompanying drawing:
[0005] FIG. 1 illustrates a dual fuel filter in a fuel injection system in accordance with one embodiment of the invention.
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Detailed description of the embodiments
[0006] FIG. 1 illustrates a dual fuel filter 12 for supplying fuel to a fuel injection system in a vehicle in accordance with one embodiment of the invention. .The dual fuel filter 12 comprises a main filter 14 and an auxiliary filter 16 placed parallel to the main filter 14. The dual fuel 25 filter 12 comprises a first pressure sensor 18 located in proximity to the main filter 14 and connected to the main filter 14. The first pressure sensor 18 senses pressure in the main filter 14. The dual fuel
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filter 12 comprises a second pressure sensor 20 located in proximity 5 to the auxiliary filter 16 and connected to the second pressure sensor 20. The second pressure sensor 20 senses pressure in the auxiliary filter 16. The dual fuel filter 12 comprises an inlet valve 22 positioned upstream to the main filter 14 and the auxiliary filter 16 and an outlet valve 24 positioned downstream to the main filter 14 and the 10 auxiliary filter 16.
[0007] Further construction of the fuel injection pump 10 and the components of the fuel injection pump 10 is explained as follows. The fuel injection system 10 comprises an engine 30 and a fuel pump 28, 15 both connected to the dual fuel filter 12. The fuel from the fuel pump 28 passes through the mail fuel filter 14 or auxiliary fuel filter 16 and flows into the engine 30. The dual fuel filter 12 comprises a control unit 25 connected to the first and second pressure sensors (18, 20) and the inlet and outlet valves (22, 24). The control unit 25 as 20 disclosed above can be a fuel injection system control unit, to which the pressure sensors (18, 20) and the valves (22, 24) are connected. The first and second pressure sensors (18, 20) of the main and auxiliary filters (14, 16) respectively can be a resistive type sensor or an inductive type sensor. However, the type of the pressure sensor 25 (18, 20) is not restricted to the above-mentioned types but can be any of the sensor type that is used to sense the difference of the pressure between two points. The pressure difference of the fuel at the inlet
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and the outlet valves (22, 24) is sensed by the first pressure sensor 5 18 when the main filter 14 is operating and by the second pressure sensor 20 when the auxiliary filter 16 is in the operation mode.
[0008] The inlet valve 22 is a solenoid operated direct control valve and the outlet valve 24 is a shutter valve. The functioning of both the 10 valves are known to the person skilled in the art. The outlet valve 24 comprises a moving structure 26 adapted to move from one position to another position, based on a signal from the control unit 25. According to one embodiment of the invention, the moving structure 26 is a ball. When the control unit 25 moves the moving structure 26 15 of the outlet valve 24, then the fuel flow path of any one of the filters (14, 16) is closed. The outlet valve 24 operates in tandem with the inlet valve 22 operation. I.e., when the control unit 25 changes the state of the inlet valve 22, the state of the outlet valve 24 alters based on the changed state of the inlet valve 22. For instance, if the control 20 unit 25 closes the inlet valve 22 and stops the fuel entering the main filter 12, then, simultaneously, the control unit 25 moves the moving structure 26 in the outlet valve 24 to close the outlet path of the fuel of the main filter 12.
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[0009] The working of the dual fuel filter 12 in the fuel injection system 10 is explained as follows. The fuel from the fuel pump 28 is pumped into the engine 30 via the main filter 12 and the first pressure
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sensor 18 senses the pressure of the fuel flowing into the main filter 5 12 (i.e., at inlet side) and the pressure at the outlet side. The main filter 14 filters out all the impurities in the fuel and the uncontaminated fuel is supplied to the engine 30. Over a period, due to the impurities in the fuel flowing via the main filter 14, the main filter 14 will be clogged. Due to the clogging of the main filter 14, the 10 pressure difference between the inlet fuel and the outlet fuel increases. For instance, the pressure difference of the fuel between the inlet and the outlet sides should be in the range of 0.1- 0.8 bar. The control unit 25 compares the detected pressure difference between the inlet fuel and the outlet fuel with a predefined value. If 15 the detected value is more than the predefined value, then the control unit 25 detects the clog in the fuel filter (18, 20). The control unit 25 is adapted to close the inlet valve 22 and the outlet valve 24 for the main filter 14, upon detecting a clogging of the main filter 14 when pressure difference from the first pressure sensor 18 of the main filter 20 14 is more than the predefined value. For instance, if the pressure difference of the fuel is more than 0.8bar, then the control unit 25 detects the clog in the main filter 14 when the main filter 14 is operating.
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[0010] Upon detecting the clog in the main filter 14, the control unit 25 operates the inlet valve 22, such that, the fuel flow path via the main filter 14 is closed at the inlet side and the fuel flows via the
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auxiliary filter 16 into the engine 30. Simultaneously, the control unit 5 25 operates the outlet valve 24 by moving the moving structure 26 present in the outlet valve 24. The moving structure 26 closes the fuel flow path via the main filter 14 at the outlet side and opens the path for the fuel to flow from the auxiliary filter 16. The control unit 25 is adapted to close the inlet valve 22 and said outlet valve 24 for the 10 auxiliary filter 16 , upon detecting a clogging of the auxiliary filter 16, when pressure difference from the second pressure sensor 20 of the auxiliary filter 16 is more than the predefined value. Thus, upon detecting the clog of any one of the two filters (14, 16) (main or auxiliary) the control unit 25 directs the fuel to flow through another 15 filter. The control unit 25 alerts the user of the vehicle by any one of the altering means (not shown) comprising a display warning, an audio, or the like, regarding the clogging of the fuel filter (14/16).
[0011] With the above disclosed dual fuel filter 12, the fuel injection 20 system 10 efficiency is improved. The manual intervention to change the direction of the fuel when one of the fuel filter (14/16) is clogged is avoided due to the automatic operation of the control unit 25 in changing the direction of the fuel. The detection of the clog of the fuel filter (14/16) based on the pressure difference is a cost-effective 25 solution as there is no requirement of usage of any expensive infrastructure. Auto switching of the filters (14, 16) by the control unit 25 helps in smooth operation of the vehicle.
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[0012] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of 10 the claims.