Claims:We Claim:
1. A fuel injection system (100), said system comprising at least a low pressure circuit (102), said low pressure circuit (102) comprising:
a fuel tank (104), a fuel filter (106) and a fuel injection pump (108), characterized in that:
a flow connector (110) connected downstream to said fuel filter (106) and upstream to said fuel injection pump (108); and
a return flow path (113), said return flow path (113) in flow communication with said fuel tank (104).

2. The fuel injection system (100) of claim 1, wherein said flow connector 110 is a three-way connector.

3. The fuel injection system (100) of claim 1, wherein said flow connector (110) comprises a throttle (115).
, Description:Field of the invention
[0001] This invention relates to the field of a fuel injection system.

Background of the invention
[0002] A fuel injection system with electric feed pump is known in the art. The electric feed pump delivers the quantity of fuel as required in the rail/ fuel distributor block. The fuel from the electric feed pump first flows through a low pressure circuit before reaching a fuel injection pump. The fuel in the fuel injection pump is pressurized and then the fuel flows through a high pressure circuit to reach the rail/ fuel distributor block. There are instances when the fuel is no longer required for injection into the engine cylinder. For example, when a vehicle is coasting down a hill, the fuel that is remaining in the low pressure circuit is no longer required for injection. Also, the since the electric feed pump operates at minimum voltage, there will always be some quantity of fuel in the low pressure circuit. This fuel that is remaining needs to be relieved from the low pressure circuit as the fuel remaining in the low pressure circuit may cause pressure fluctuations in the fuel injection system.

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 injection system.

Detailed description of the embodiments
[0005] FIG. 1 illustrates a fuel injection system 100. The system comprises a low pressure circuit 102. The low pressure circuit 102 comprises a fuel tank 104, a filter 106 and a fuel injection pump 108. The fuel injection system 100 further comprises a flow connector 110 connected downstream to the filter 106 and upstream to the fuel injection pump 108 and a return flow path 113, the return flow path 113 in flow communication with the fuel tank 104.

[0006] The structure of fuel injection system 100 will be explained in detail. The fuel injection system 100 comprises a fuel tank 104. Located in the fuel tank 104 is an electric feed pump. The electric feed pump supplies fuel to the high pressure pump in dependence of the amount of fuel that needs to be supplied to the injector. The fuel from the electric feed pump flows along a path leading to the fuel filter 106. From the fuel filter 106 the fuel flows into the fuel injection pump 108. The fuel received in the fuel injection pump 108 is pressurized and sent to the rail/ fuel distributor block 111 for injection into the engine cylinder. The part of the fuel injection system 100 between the fuel tank 104 and the fuel injection pump 108 is called the low pressure circuit 102, and the part of the fuel injection system 100 between the fuel injection pump 108 and the common rail is called the high pressure circuit. The low pressure circuit 102 comprises a flow connector 110 connected downstream to the fuel filter 106 and upstream to the fuel injection pump 108 and a return flow path 113. The flow connector 110 is a three-way connector. The flow connector (110) comprises a throttle 115. The function of the throttle is to control the flow of fuel through the return flow path 113. The throttle size in the flow connector is designed such that the flow from electric feed pump at minimum voltage can be relieved back to the return flow path. Also this will reduce the pressure oscillations at the inlet of fuel injection pump and helps in stabilizing the inlet pressure.. The return flow path 113 is in flow communication with the fuel tank 104.. The throttle size in the connector is such that the flow from electric feed pump at minimum voltage can be relieved back to the return flow path 113. Also this will reduce the inlet pressure oscillations at the inlet of fuel injection pump 108 and helps in stabilizing the inlet pressure. A first end 112 of the three-way connector is in flow communication with the fuel tank 104. The fuel received through the first end 112 of the three-way connector flows to the fuel injection pump 108 through a second end 114. The three-way connector has a third end 115 connected to the return flow path 113. The fuel that is remaining in the low pressure circuit 102 is relieved through the return flow path 113 back to the fuel tank 104. With the introduction of flow connector with throttle in the low pressure circuit, a small amount of flow at the minimum operating voltage of the electric feed pump can be relieved and flow towards the fuel injection pump can be reduced.
[0007] By providing a return flow path 113 in the low pressure circuit 102 it is possible to prevent excess fuel from entering the fuel injection pump 108. Also by using a flow connector 110 with the return flow path 113 in the low pressure circuit 102, flow to the fuel injection pump 108 will be stabilized. Minimum flow of electric feed pump is maintained for stable operation.
[0008] 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 type of. 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.