Claims:We Claim:
1. A high pressure pump (100) in a fuel injection system (102), said fuel injection system 102 comprising:
a fuel tank (104) located upstream to said high pressure pump (100), said high pressure pump (100) comprising an inlet flow path (106) to receive fuel from said fuel tank, an outlet flow path (108) of said high pressure pump (100) in flow communication with a common rail (110) of said fuel injection system (102), and with a first backflow path (112); characterized in that:
said high pressure pump 100 comprising a second backflow path (114), said second backflow path (114) adapted to open in dependence of the pressure of fuel in said high pressure pump 100.

2. The high pressure pump 100 of claim 1, wherein said second backflow path (114) comprises a spring loaded ball valve.
, 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]This invention relates to the field of high pressure fuel injection pump in a fuel injection system.

Background of the invention
[0002]A high pressure pump is used to pressurize fuel received from a fuel tank before the fuel reaches the common rail for injection into the engine cylinder. Fuel from the fuel tank enters the high pressure pump through the inlet and is delivered to the common rail through the outlet. The high pressure pump also comprises a backflow path to enable excess fuel from the pump to flow back to the fuel tank. A sealing ring is used in the high pressure pump to prevent mixing of fuel and oil. The sealing ring is susceptible to damages due to high backflow pressure of fuel resulting in mixing of fuel and oil. Backflow pressure could be caused due to interchange of inlet and backflow hose pipes. There is a need to avoid damages to the components of the high pressure pump.

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 high pressure pump in a fuel injection system.

Detailed description of the embodiments
[0005] FIG. 1 illustrates a high pressure pump 100 in a fuel injection system 102. The fuel injection system 102 comprises a fuel tank 104 located upstream to the high pressure pump 100, the high pressure pump 100 comprises an inlet flow path 106 to receive fuel from the fuel tank 104, and an outlet flow path 108 of the high pressure pump 100 is in flow communication with a common rail 110 of the fuel injection system 102. The high pressure pump 100 comprises a first back flow path 112 and a second backflow path 114 that is adapted to open in dependence of the pressure of fuel in the high pressure pump 100. In an embodiment the second backflow path 114 comprises a spring loaded ball valve.

[0006]The working of the high pressure pump 100 and the fuel injection system 102 will now be explained in further detail. The fuel injection system 102 comprises a fuel tank 104 that stores fuel, the fuel tank 104 is located upstream to the high pressure pump 100. The high pressure pump 100 comprises an inlet flow path 106 to receive fuel from the fuel tank 104 via a fuel filter 103. The fuel upon entering the high pressure pump 100 gets pressurized and is then delivered to the common rail 110 where the fuel is injected into the engine cylinder. The fuel injection pump also comprises a first backflow path 112 and a second backflow path 114. The second backflow path 114 is adapted to open in dependence of the pressure of fuel in the high pressure pump 100. In an embodiment the second backflow path 114 comprises a spring loaded ball valve.

[0007]The movement of fuel through the first backflow path 112 and the second backflow path 114 will be explained in further detail. The function of the first backflow path 112 is to receive excess fuel from the components of the high pressure pump 100, like the housing, zero delivery throttle, and flange of the high pressure pump 100 and return the fuel to the fuel tank 104. In case the pressure of fuel within the high pressure pump 100 exceeds a threshold pressure, then the fuel forces the spring loaded ball valve that is located along the second backflow path to open. This relives the pressure within the high pressure pump 100 thereby prevents damage to the components of the high pressure pump 100.

[0008] ‘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.

[0009]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 high pressure pump 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.