Claims:We Claim:
1. An overflow valve (100) for a fuel injection system comprising,
a hollow cylinder (101) having two ends, a first end of said two ends is sealed;
a spring element (102) assembled in said hollow cylinder (101) such that a first end of said spring element (102) abuts a profile (103) and second end of said spring element (103) abuts a piston (104);
a holder (105) threaded at second end of said hollow cylinder (101); said holder (105) adapted to hold said piston (104) inside said hollow cylinder (101); and
at least one outlet (106) in said hollow cylinder (101); said outlet (106) allows a fluid to flow outside said overflow valve (100).

2. The overflow valve (100) as claimed in claim 1, wherein said holder (105) has a flow path.

3. The overflow valve (100) as claimed in claim 1, wherein at least one shim plate (107) inserted axially in said hollow cylinder (101) from said second end in proximity of said first end.

4. The overflow valve (100) as claimed in claim 1, wherein said profile (103) is accommodates said first end of said spring element (102) inside said first end of said hollow cylinder (101).

5. The overflow valve (100) as claimed in claim 1, wherein said at least one orifice (108) is located on said hollow cylinder (101).
, 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 an overflow valve for a fuel injection system.

Background of the invention
[0002] An overflow valve is a valve used to perform pressure bypasses for safety purposes in order to protect lines, pumps etc. It is designed to prevent risks and possible failures caused by pressure surges in the system. The overflow valve is calibrated to a specific pressure by regulating the spring with the pressure. When the pressure in the circuit exceeds the calibrated pressure, the valve opens letting the flow pass and reducing the pressure of the pipe system.

[0003] The patent application US20110174270A1 discloses a pressure relief valve. A pressure relief valve suitable for limiting fluid pressure in a common rail of a fuel injection system comprises a first housing part having a first through-bore with a first segment, a second segment and the valve seat defined in between. A second housing part is screw fastened with the first housing part. In addition, includes a second through-bore disposed coaxially to the first through-bore. An overall rod-shaped valve member is axially displaceable within the second segment. A spring biases the valve member towards the valve seat. A portion of the valve member opposite of the valve seat includes a shaft having a terminal end formed with a non-round cross-section. In addition, configured in a way that a tool inserted through the second through-bore and engaging the non-round cross-section prevents the terminal end and the valve member from rotating relative to the first housing part when the first and second housing parts are screwed together.

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 the overflow valve according to an embodiment in the invention.

Detailed description of the embodiments
[0006] Figure 1 illustrates an overflow valve 100 for a fuel injection system according to an embodiment of the disclosure. An overflow valve 100 for a fuel injection system comprises a hollow cylinder 101 having two ends; a first end of the two ends is sealed. The over flow valve 100 comprises a spring element 102 assembled in the hollow cylinder 101 such that a first end of the spring element 102 abuts a profile 103 and second end of the spring element 102 abuts a piston 104. The overflow valve 100 further comprises a holder 105 threaded at a second end of the hollow cylinder 101, the holder 105 is adapted to hold the piston 104 inside the hollow cylinder 101 and at least one outlet 106 in the hollow cylinder 101, the outlet 106 allows a fluid to flow outside the overflow valve 100.

[0007] Here the hollow cylinder 101 is not restricted to any type but to any component which is sealed at one end and suitable for the fluid. The hollow cylinder 101 is robust so to maintain the pressurized fluid under the functioning of the overflow valve 100. In the overflow valve 100, the holder 105 has a flow path. The fluid flows to the holder 105 after entering from the second end of the hollow cylinder 101 and flows out via outlet 106. From the outlet 106, the fluid flows to the fuel tank. The holder 105 is adapted to hold the piston 104 of any shape and size required for the functioning of overflow valve 100.

[0008] In the overflow valve 100, at least one shim plate 107 is inserted axially in the hollow cylinder 101 from a second end in proximity of the first end. The shim plate 107 are used to fill the space inside the hollow cylinder 101 based on the pressure required for the compression of the spring element 102. Any number of shim plate 107 is inserted axially inside the hollow cylinder 101 based on the requirement of the pressure inside the overflow valve 100.

[0009] According to one embodiment of the disclosure, in the overflow valve 100, the profile 103 accommodates the first end of the spring element 102 inside the first end of the hollow cylinder 101. The profile 103 is not limited to any particular shape but able to accommodate the first end of the spring element 102.

[0010] According to another embodiment of the invention, at least one orifice 108 is located on the hollow cylinder 101 of the overflow valve 100. When the overflow valve 100 is closed, i.e. in non-functioning mode, the fluid in the clearances from the spring element 102 and piston 104 flows out from this orifice 108 to the tank. The orifice 108 is different from the outlet 106 of the overflow valve 100 and is only used to clear the fluid in between the piston 104 and spring element 102 during non-functioning mode of the overflow valve 100

[0011] In the fuel injection system, the fluid from the tank flows to the pump and then to the common rail. From the common rail, the pressurized fluid flows to the injector then the fuel injection takes place in the combustion chamber. In the system, there are situations where the pressure increases more than the requirement in the circuit for example in the pump or in the injector. Therefore the overflow valve 100 is used. The overflow 100 valve is in fluid communication with the components of the fuel injection system for example the pump or injector. The connection of the overflow valve 100 with the components of fuel injection system is not limited to any particular type or mechanism.

[0012] The working of the overflow valve 100 is disclosed in accordance to the embodiment of the invention. The fluid enters the overflow valve 100 via the second end of the overflow valve 100 and flows to the holder 105. Due to the pressure of the fluid, the fluid enters the holder 105 and reciprocates the piston 104, which in turn compresses the spring element 102. This leads to opening of the outlet 106 and fluid flows through the outlet 106 back to the tank. Once the pressure of the fluid starts reducing and reaches to the normal value, the spring element 102 comes back to the original position by pushing the piston down towards the holder 105 and closing the outlet 106 of the overflow valve 100.

[0013] By using this type of overflow valve 100, the leakage of the fluid is avoided as it is sealed from one side and flow communication happens from one side and then the fluid flows to the tank via outlet 106. The assembly of the overflow valve 100 is smooth so cracks during the assembly is reduced unlike the conventional assembly process. The opening pressure is adjusted by placing the shim plate 107. This overflow valve 100 is used in every component of the fuel injection system 100 where the fluid pressure needs to be maintained for example in the pump or in the fuel injector in the fuel injection system.

[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. 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.