Field of the invention
[0001]This invention relates to the field of fuel filter in a fuel injection system.
Background of the invention
[0002]In a fuel injection system an electric feed pump is located in a fuel tank is used during engine start condition to supply fuel to the high pressure fuel injection pump via a feed pump located proximal to the high pressure fuel injection pump. Once the engine gains speed, the electric feed pump is switched “OFF” and the feed pump that is driven by the engine receives sufficient force to suck fuel from the fuel tank. During operation of the feed pump, there is need to ensure that the fuel that was initially supplied by the electric feed pump during engine start condition does not flow back to the fuel tank.
Brief description of the accompanying drawing
[0003] Different modes of the invention are disclosed in detail in the description
and illustrated in the accompanying drawing:
[0004] FIG. 1 illustrates a fuel filter in a fuel injection system during engine start phase;
[0005] FIG. 2 illustrates a fuel filter in a fuel injection system during working of the engine; and
[0006] FIG. 3 illustrates a fuel filter in a fuel injection system during hydro-carbon injection (HCI) dosing.

[0007] FIG. 4 illustrates a graph showing filter status during working of the fuel injection system.
Detailed description of the embodiments
[0008] FIG. 1 illustrates a fuel filter 102 in a fuel injection system during engine start phase. The fuel filter 102 is located upstream to a fuel tank 104, and downstream to a high pressure pump 106 and comprises a first flow path 108. The first flow path 108 is in flow communication with the fuel tank 104. The fuel filter 102 comprising at least a second flow path 110, the second flow path 110 is in flow communication with an electric feed pump 111 located in the fuel tank 104 and a solenoid 112 is located along the second flow path 110, the solenoid 112 is adapted to open the second flow path 110 into any one of the fuel filter 102 and a dosing injector 114. In an embodiment the solenoid 112 is actuated via an electronic control unit. A flow control valve 109 is located at the interface of the first flow path 108 and second flow path 110.
[0009]Consider the case during engine start phase. When the engine is started the electric feed pump 111 is switched “ON”, the electric feed pump 111 delivers fuel to the fuel filter 102 through the second flow path 110, the fuel then reaches the interface 105 of the first flow path 108 and the second flow path 110. The pressure of fuel causes the flow control valve 109 to block the first flow path 108. Now, the fuel flows within the fuel filter 102 and reaches the high pressure pump 106.
[0010] FIG. 2 illustrates a fuel filter 102 in a fuel injection system during working of the engine. When the engine starts driving the feed pump 107, the electric feed pump 111 is switched “off” and the suction force generated by the feed pump 107 causes the fuel to flow through the first flow path 108. The

pressure of the fuel causes the flow control valve 109 to lift thereby causing the fuel to flow within the fuel filter 102 and reach the high pressure pump 106.
[0011] FIG. 3 illustrates a fuel filter 102 in a fuel injection system during hydro¬carbon injection (HCI) dosing. Consider the case when there is dosing requirement along the exhaust flow path. For enabling dosing the fuel in the fuel tank 104 needs to flow at a pressure that is controlled by the valve 105 that is present in the fuel tank 104. Alternatively the valve may be in-between the electric feed pump 111 and the fist flow path 108. When the electric feed pump 111 is switched “ON” and the solenoid 112 is actuated via the electronic control unit. The solenoid 112 blocks the second flow path 110, and the fuel from the electric feed pump 111 flows along the dosing flow path 107 to reach the dosing injector 114. The dosing injector then injects fuel along the exhaust path. During dosing, the first flow path 108 provides fuel to the high pressure pump 106.
[0012] Hence with the use of the above fuel filter 102 with plurality of flow paths (first flow path 108 and second flow path 110 it is now possible to supply fuel during various requirements like dosing, engine start and during normal working of engine.
[0013] FIG. 4 illustrates a graph showing filter 102 status during working of the fuel injection system. During start phase the electric feed pump 111 is kept “ON”, the feed pump 107 is kept “ON” during the normal running of the engine and during HCI dosing. The flow control valve 109 is closed during the engine start phase. The valve 113 is kept “ON” during working of the fuel injection

system 100. The port 115 opens only during there is requirement for HCI dosing along with the solenoid valve 112.
[0014] ‘Adapted’ or ‘arranged’, in the context of the instant disclosure, refers to the technical capability or the technical capacity of a component, in relation to which the term ‘adapted’ or ‘arranged’ is used, to carry out or executed a specified action or actions, upon the requirement of the specified action or actions to be carried out or executed. Moreover, the usage of the term ‘adapted’ or ‘arranged’ here, is in reference with the normal technical capability or technical capacity of the component, imparted by the design or the structure or the composition of the component, and not in reference with any special or extraneous capability or capacity, beyond the scope of the normal technical capability or technical capacity. Therefore there is a need to address this problem.
[0015]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of solenoid or fuel filter used. 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 the claims.

CLAIMS
We Claim:
1. A fuel filter (102) in a fuel injection system (100), said fuel filter (102)
located upstream to a fuel tank (104), and downstream to a high
pressure pump (106) and comprising a first flow path (108) said first
flow path 108 in flow communication with said fuel tank (104),
characterized in that:
said fuel filter (102) comprising at least a second flow path (110), said second flow path (110) in flow communication with an electric feed pump (111) located in said fuel tank (104); and a solenoid (112) located along said second flow path (110), said solenoid (112) adapted to open said second flow path (110) into any one of said fuel filter (102) and a dosing injector (114).
2. The fuel filter (102) of claim 1, wherein said solenoid is actuated via an electronic control unit.
3. The fuel filter (102) of claim 1, wherein a flow control valve 109 is located at the interface of said first flow path 108 and said second flow path 110.