Claims:We Claim:

1. A common rail fuel injection system (100) comprising,
a filter (101) having an inlet (101a) and an outlet (101b), an inlet (101a) is connected to a fuel tank (102);
at least one pump (103) connected to said outlet (101b) of said filter (101);
Characterized in that
a flow path (104) connecting said pump (103) to said inlet (101a) of said filter (101) for backflow of fuel from said pump (103) to said filter (101).
2. A common rail system (100) as claimed in claim 1, wherein said flow path (104) is a pipe.
3. A common rail system (100) as claimed in claim 1, wherein said flow path (104) has fins.
4. A common rail system (100) as claimed in claim 1, wherein said flow path (104) has a non-return valve (104a) located at one of said flow path (104).
, 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 invention relates to a common rail fuel injection system.

Background of the invention
[0002] The common rail fuel injection system is a direct fuel injection system for diesel engines. In common rail system, fuel is distributed to the injectors from a high-pressure rail. A high-pressure fuel pump feeds the rail. The pressure in the rail and a signal that activates the injector for each cylinder are electronically controlled. Advantages of common rail system includes flexibility in controlling both injection timing and injection rate.

[0003] The patent application DE102016209724A1 discloses high pressure pump for a fuel injection system. The invention relates to a high pressure pump for a fuel injection system, in particular a common-rail injection system, connected to a multi-part housing comprising a base housing and the basic housing cylinder head. A cylinder bore is configured for receiving a lift able pump piston, wherein the pump piston inside the cylinder bore defining a high-pressure chamber element, which can be filled with fuel via a suction valve. According to the invention, in the cylinder head is formed a feed channel for the supply of the suction valve with fuel, whereby in the inlet conduit a filter and an opening in the inlet direction non-return valves are arranged.

Brief description of the accompanying drawings:
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:
[0005] FIG. 1 illustrates a view of a common rail fuel injection system according to an embodiment in the invention.

Detailed description of the embodiments
[0006] Figure 1 illustrates a common rail fuel injection system 100.
A common rail fuel injection system 100 comprises a filter 101 having an inlet 101a and an outlet 101b, an inlet 101a is connected to a fuel tank 102, at least one pump 103 connected to the outlet 101b of the filter 101. The common rail fuel injection system 100 further comprises a flow path 104 connecting the pump 103 to the inlet 101a of the filter 101 for backflow of fuel from the pump 103 to the filter 101.

[0007] According to one embodiment of the invention in the common rail fuel injection system 100, the fuel flows from the fuel tank 102 to the pump 103 after being filtered from a filter 101. In the pump 103, the fuel is pressurized and this pressurized fuel flows to common rail 105 and from common rail 105 to the injector 106. The injector 106 injects the pressurized fuel into the engine based on the requirement. The electronic control 107 unit ensures that the start of injection, the quantity of fuel and time are independent of the engine speed. The backflow of fuel from the pump 103 flows through the flow path 104 to the inlet 101a of the filter 101.

[0008] In the above disclosed disclosure, the flow path 104 has a non-return valve 104a to prevent the fuel flowing from the inlet 101a of the filter 101 to the pump 103. The fuel flows from the outlet 101b of the filter 101 to the pump 103. The non-return valve 104a allows only one-way flow of the fuel in the flow path 104. Therefore, the fuel from the pump 103 flows only to the inlet 101a of filter 101 via flow path 104 and not vice versa.

[0009]In the common rail fuel injection system 100, the fuel is sent to filter 101 from the fuel tank 102. From filter 101, the fuel is delivered to the pump 103. In the pump 103, the fuel is pressurized and sent to the common rail 105. Here the excess or overflow fuel from the pump 103 is returned to the inlet 101a of the filter 101 via flow path 103. The backflow of fuel from pump 103 to filter 101 prevents the fuel starvation at the filter 101, when there is a sudden requirement of fuel inside the filter 101. The backflow of fuel makes sure that the fuel will be always available inside the filter 101.

[0010] In a common rail system 100 the flow path 104 is a pipe and the flow path 104 has fins. The flow path 104 is made thick and will be surrounded with fins in order to increase the surface area of flow path 104. The increase in surface area will enable the heat dissipation.

[0011] The backflow of the fuel serves two functions - dissipation of heat and filtering the fuel. During the heat dissipation, the temperature of backflow fuel increases due to system vibrations and frictional forces. Due to frictional forces, the wear and tear of the pump components takes place during dry run. To prevent choking of the pump 103 and clogging of filter 101, here the backflow fuel is made to pass through the inlet 101a of the filter 101 via flow path 104 to the pump 103. Thus, the filtered fuel is sent to the pump 103. Delivery of back flow fuel to tank 102 encourages heat dissipation and again filtration of fuel is loss of energy. Instead, overflow fuel can be delivered directly to filter 101 and thus saving energy and solve the fuel filter starvation and other issues related to filter 101.

[0012] By using the arrangement of the common rail fuel injection system 100 as disclosed above, the loss of energy used to suck the fuel from the tank 102 and sent to the filter 101 can be prevented.

[0013] ‘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

[0014] 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 the claims.