Claims:We Claim:
1. A high pressure fuel pump (100) for a vehicle, said high pressure fuel pump (100) comprising at least a inlet valve (102) in fluid communication with a fuel inlet (101), a first leak off groove (103) providing a fluid communication between the inlet and a plunger sealing chamber (104), characterized in that fuel pump, a second leak off groove (105) providing a fluid communication between the plunger sealing chamber (104) and a throttle (106).

2. The high pressure fuel pump (100) for a vehicle as claimed in claim 1, wherein the second leak off groove (105) is a channel made in housing of the high pressure fuel pump.

3. The high pressure fuel pump (100) for a vehicle as claimed in claim 1, wherein the throttle (106) provides fluid communication between the second leak-off groove (105) and the inlet valve (102).

4. The high pressure fuel pump (100) for a vehicle as claimed in claim 1, wherein the throttle (106) is provides a constricted opening for air bubbles to be vented out.
, 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 disclosure relates to a high pressure fuel pump for a vehicle. More specifically it relates to a plug-in type high pressure fuel pump.

Background of the invention
[0002] A fuel injection system is operated such that the fuel is channeled to a high pressure fuel pump where it is pressurized and delivered to a high pressure common rail. Sometimes fuel channeled to the high pressure fuel pump has air pockets. The high pressure fuel pump comprises a plunger sealing chamber, which further has a plunger sealing ring. Plunger sealing ring is used in plug in type of pumps to separate oil from fuel. Entrapment of air pockets in plunger sealing chamber can lead to pressure oscillations in the fuel supply circuit. The problem would be more critical if pump is mounted in an inclined position (not vertical). In order to release the air pockets that are present in the fuel, an arrangement for venting air before an inlet from the high pressure fuel pump is required.

[0003] Published patent application IN04190CH2014AA titled “High Pressure Fuel Pump” discloses a high pressure fuel pump (10) that includes an inlet port (12) provided in a housing (14) of the high pressure fuel pump (10), and an inlet connector (16) connected to the inlet port (12). An orifice (20) is provide d in the inlet connector (16), and an air bleed component (24) is fitted in the orifice (20) to facilitate venting air from the orifice (20) of the inlet connector (16) of the high pressure fuel pump (10).

Brief description of the accompanying drawings
[0004] An embodiment of the invention is described with reference to the following accompanying drawing:
[0005] Figure 1 depicts a high pressure fuel pump (100) for a vehicle.

Detailed description of the drawings

[0006] Figure 1 depicts a high pressure fuel pump (100) for a vehicle. Figure 1 depicts a high pressure fuel pump (100) for a vehicle. The high pressure fuel pump (100) forms a part of a fuel supply circuit for an internal combustion engine. It is usually placed upstream from a common rail and downstream from a fuel filter. The fuel entering the fuel pump from fuel filter is not pressurized, the function of the fuel pump is to pressurize this fuel and deliver it to the common rail.

[0007] The high pressure fuel pump (100) comprises a fuel inlet (101), an inlet valve (102), a first leak-off groove (103), a plunger sealing chamber (104) and at least a second leak-off groove (105). The inlet valve (102) is in fluid communication with a fuel inlet (101). Fuel inlet (101) is a path for ingress of fuel coming from the fuel filter. The first leak off groove (103) provides a fluid communication between the inlet and the plunger sealing chamber (104). In the current design the plunger sealing ring to prevent/reduce oil and fuel mixing is placed in the plunger sealing chamber (104) pressed into a housing of the pump with interference fit. Additionally a washer is used to close the plunger sealing chamber (104). The gap between the plunger sealing ring top and housing acts as a connection between the plunger clearance and the leak off groove.

[0008] The most important non-limiting feature of the high pressure fuel pump (100) is the second leak off groove (105) providing a fluid communication between the plunger sealing chamber (104) and a throttle (106). The throttle (106) provides fluid communication between the second leak-off groove (105) and the inlet valve (102). The second leak off groove (105) is a channel made in housing of the high pressure fuel pump (100). The throttle (106) provides a constricted opening for air bubbles to be vented out. In this proposed design of the high pressure fuel pump (100), the second leak off groove (105) is connected to the inlet valve (102) area opposite to the fuel inlet (101). The throttle (106) is placed in connection between the second leak of groove and the inlet valve (102).

[0009] This arrangement allows the fuel that passes through the first leak off groove (103) and pushes the air in the plunger sealing chamber (104) into the second leak off groove (105). The throttle (106) ensures that the air is released in a controlled manner to the inlet valve (102) area without causing pressure oscillation. The air is then delivered to the high pressure side i.e. the upstream components such as common rail and fuel injectors. These air pockets then returns to the tank through return flow path of the common rail or the fuel injectors.

[0010] This idea to develop a high pressure fuel pump (100) with a second leak-off groove (105) configured to operate as an air venting provision is a cost effective and highly reliable design that facilitates venting of air pockets out of the plunger sealing chamber (104). Such a design mitigates pressure oscillation in the fuel supply circuit of an internal combustion engine improving the functional robustness of the system.

[0011] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the high pressure fuel pump (100) are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.