Claims:We claim: -
1. A fuel injection pump (100) of a fuel supply system; said fuel injection pump (100) comprises:
at least one drive shaft (20) and at least one bearing (30);
at least one sealing ring (40) placed between said drive shaft (20) and a flange (50) of said fuel injection pump (100); characterized in said fuel injection pump (100):
a channel (60) on said flange (50); and
a pressure relief valve (70) is placed in said channel (60) of said flange (50).
2. The fuel injection pump (100) as claimed in claim 1, wherein said channel (60) is coupled to a pump cavity (80).
3. The fuel injection pump (100) as claimed in claim 1, wherein said pressure relief valve (70) opens up when pressure of a fuel coming/leaking out said pump cavity (80) is more than a threshold value.
4. The fuel injection pump (100) as claimed in claim 3, wherein said pressure relief valve (70) gets closed when pressure of said fuel coming/leaking out said pump cavity is lesser a threshold value.
5. The fuel injection pump as claimed in claim 1, wherein said fuel injection system is used in at least one of a vehicle, a power generator, and a water craft.
6. The fuel injection pump (100) as claimed in claim 3, wherein said pressure relief valve (70) restricts the displacement of said at least one seal ring (40) due to variation in pressure of fuel leaking out said pump cavity (80).

, 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 present invention relates to pressure relief valve for a fuel injection pump. More specifically, the invention relates to avoiding displacement of shaft sealing rings of fuel injection pump due to pressure pulsations.
Background of the invention:
[0002] Fuel injection system has a low-pressure pump and a high-pressure pump. From diesel tank, fuel is taken up to diesel filter via an electric pump and finally to high pressure pump. Inside the high-pressure pump, incoming fuel gets pressurized to be delivered to the engine cylinders through high pressure common rail injectors. The high-pressure pump has camshaft, plunger, flange, sealing rigs, drive shaft, etc. Between the drive shaft and the plunger, a sealing ring is placed for effective sealing. If the pressure inside the pump reaches certain threshold value, the sealing ring gets displaced. The displacement of sealing ring leads to the spillage of fuel outside the pump and sealing ring needs to be replaced manually every time after the displacement.
[0003] A US patent 8,287,231 discloses a pressure relief arrangement for a pump which includes a pump housing assembly with a pumping chamber. There is a shearing element which fails once the pressure increases, thereby permitting movement of the section from normal operating position to the venting position. Once, the shearing element gets failed, it needs to be replaced.
[0004] The present disclosure is directed towards overcoming one or more shortcomings set forth above.
Brief Disclosure of the Invention:
[0004] The invention discloses a a fuel injection pump of a fuel supply system. The fuel injection pump comprises a driver shaft, one or more bearings and one or more shaft sealing rings. One or more sealing rings are placed between the drive shaft and the flange of the fuel injection pump.
[0005] A channel is created on the flange of the fuel injection pump, which is coupled to a pump cavity. A pressure relief valve is placed in the channel. When the pressure of the fuel coming/leaking out of the pump cavity reaches a threshold value, the pressure relief valve is opened.
[0006] The pressure relief valve gets closed when the pressure of the coming fuel in the pump cavity remains below the threshold value. As a result, the unwanted displacement of the sealing ring due to variation in pressure of the fuel in the pump cavity is avoided.
[0007] The fuel supply system is used in vehicles, power generator, watercraft, etc.
Brief description of the accompanying drawings:
[0008] An embodiment of the disclosure is described with reference to the following accompanying drawings:-
[0009] Fig. 1 illustrates a schematic view of a fuel injection pump, according to an embodiment of the present invention.
[0010] Fig. 2 illustrates an enlarged cut section of a high-pressure pump, according to an embodiment of the present invention.
[0011] Fig 3. Illustrates a schematic view of the pressure relief valve according to an embodiment of the present invention.

Detailed description of the embodiments:
[0012] Fig. 1 illustrates a schematic view of a fuel injection pump, according to an embodiment of the present invention. The fuel injection pump 100 has a drive shaft 20. Further parts of the fuel injection pump are explained using in Fig. 2. Fig. 2 illustrates the enlarged section of the flange of a fuel injection pump according to an embodiment of the invention. The fuel injection pump 100 shown in the figure is a high-pressure pump. The fuel injection pump 100 comprises a drive shaft 20, one or more bearings 30. One or more sealing rings 40 are placed between the drive shaft 20 and a flange 50 of the fuel injection pump 100 for effectively sealing the area around the drive shaft 20 and a pump cavity 80. A channel 60 is formed in the flange 50 of the fuel injection pump 100. The channel 60 may be formed using different techniques such as drilling. A pressure relief valve 70 is inserted in that channel 60.
[0013] Fig. 3 illustrates schematic view of a pressure relief valve 70 according to an embodiment of the invention. An example of the pressure relief valve 70 is shown in the figure 3 and it should be not be construed as a limitation. The pressure relief valve has a poppet 110, a ball 90 is arranged on that poppet and a spring 120 is arranged on that ball 90. The working of the spring 120, poppet 110 and ball 90 depends on the fuel pressure inside the fuel injection pump 100.
[0014] When the pressure of the fuel inside the pump cavity 80 is more than a threshold value, the spring 120 gets pressed and releases the excess pressure. Once the excess pressure inside the pump cavity 80 is released, ball 90 pushes the spring 120 to its normal position. It is well known that the design and material of the pressure relief valve 70 can be changed to handle different threshold values of fuel pressure.
[0015] As the pressure relief valve 70 releases the excess fuel pressure in a controlled manner, the displacement, and the damage of the sealing ring 40 is avoided effectively. Hence, maintenance and repair cost of the pump is reduced. As the requirement of changing or replacing the shaft sealing ring 40 when it gets displaced due to high pressure is eliminated, hassles are reduced, and operational efficiency of the pump is improved.
[0016] 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 modification 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.