CN115370513A

CN115370513A - Fuel pump for vehicle

Info

Publication number: CN115370513A
Application number: CN202210548961.0A
Authority: CN
Inventors: G·P·安东尼
Original assignee: Robert Bosch GmbH; Bosch Ltd
Current assignee: Robert Bosch GmbH; Bosch Ltd
Priority date: 2021-05-20
Filing date: 2022-05-20
Publication date: 2022-11-22
Also published as: DE102022204765A1

Abstract

The present disclosure proposes a fuel pump (100) for a vehicle comprising a housing (101) and at least one plunger adapted to reciprocate in the housing (101). A fuel inlet (102) is provided in the housing (101), the fuel inlet providing a fluid communication path with an inlet valve (103). The leak-off groove (104) provides a fluid communication path between the inlet valve (103) and the plunger seal chamber (1053). The plunger seal chamber (1053) has at least one plunger seal ring (1054). The fuel pump (100) features an undercut (1051) in the pump housing (101) on top of the plunger seal chamber (1053) that enables fluid communication between the leakage groove and the plunger gap. Further, a gasket (1052) is positioned between the plunger seal ring (1054) and the undercut (1051).

Description

Fuel pump for vehicle

Technical Field

The present disclosure relates to a fuel pump for a vehicle. More particularly, it relates to a plug-in high-pressure fuel pump.

Background

Plunger seal rings are used in plunge fuel pumps to separate oil and fuel (fluid separation). It is observed that during operation of the plunger, either due to its up and down movement or due to the presence of some sort of friction component (such as a metal foil) in the fuel, the plunger seal is unseated and affects the desired operation of the pump and fuel system. This can result in closure of the leak groove and the plunger seal ring itself can also act as a plunger in the plunger seal chamber, resulting in pressure oscillations at the pump inlet which adversely affect fuel pressure control in the system.

Patent application CN109386418A entitled "Plunger Pump and High Pressure Fuel Pump" discloses a Plunger Pump. The plunger pump comprises a plunger sleeve, a plunger, a sealing ring sleeve and a plunger sealing ring, wherein a plunger cavity and a sealing ring chamber are defined in the plunger sleeve; the plunger axially reciprocates in the plunger cavity; a seal collar disposed in the seal ring chamber and generating an axial restraining force capable of retaining the seal collar in the seal ring chamber by an interference fit formed between the seal collar and a corresponding portion of the plunger sleeve; the plunger sealing ring is embedded in the sealing ring sleeve, and the plunger penetrates through the plunger sealing ring and is sealed by the sealing ring sleeve.

Drawings

Embodiments of the invention are described with reference to the following drawings:

FIG. 1 depicts a fuel pump (100) for a vehicle;

fig. 2 depicts a portion (105 a) of a fuel pump (100) according to a first embodiment; and

fig. 3 depicts a portion (105 b) of a fuel pump (100) according to a second embodiment.

Detailed Description

Fig. 1 depicts a fuel pump (100) for a vehicle. A fuel pump (100) forms part of a fuel supply circuit for an internal combustion engine. It is typically placed upstream of the common rail and downstream of the fuel filter. The fuel entering the fuel pump (100) from the fuel filter is unpressurized and the function of the fuel pump (100) is to pressurize and deliver the fuel to the common rail.

The fuel pump (100) according to the present invention comprises a housing (101) and at least one plunger (106) adapted to reciprocate in said housing (101). A fuel inlet (102) is provided in the housing (101), the fuel inlet providing a fluid communication path with an inlet valve (103). A leak-off groove (leak-off) (104) provides a fluid communication path between the inlet valve (103) and the plunger seal chamber (1053). The plunger seal chamber (1053) has at least one plunger seal ring (1054).

The fuel pump (100) features an undercut (1051) in the pump housing (101) on top of the plunger seal chamber (1053) that enables fluid communication between the leakage groove (104) and the plunger gap. Further, a gasket (1052) is positioned between the plunger seal ring (1054) and the undercut (1051). In an embodiment of the present disclosure, the mesh is placed inside the undercut (1051).

In conventional fuel pumps, the plunger seal ring (1054) is placed to prevent/reduce mixing of oil and fuel in the plunger seal chamber (1053). The plunger sealing ring (1054) is pressed into the pump housing (101) with an interference fit. The gap between the top of the plunger seal ring (1054) and the housing (101) serves as the connection between the plunger gap and the leakage groove (104).

Fig. 2 depicts a part (105 a) of a fuel pump (100) according to a first embodiment of the proposed fuel pump (100). In the proposed design, a special arrangement is made where the plunger sealing ring (1054) is placed between two washers (additional washer (1052) on top and one at the bottom) to limit the axial movement of the plunger sealing ring (1054). The plunger seal chamber (1053) is dimensioned in such a way that it will still have a small gap to allow the plunger seal ring (1054) to expand and contract.

The most important non-limiting feature of the fuel pump is that special undercuts are made in the housing (101) to connect the plunger gap and the leakage groove (104), which will enable the function of the leakage groove (104) to be continued, ensuring limited oil and fuel mixing and providing a path for a small amount of leakage to return to the fuel inlet (102).

Fig. 3 depicts a part (105 b) of a fuel pump (100) according to a second embodiment, wherein a mesh is placed inside the undercut (1051) in addition to the features of the first embodiment. The mesh functions to prevent coarse particles in the fuel from entering the plunger seal chamber, which rub against the plunger seal ring (1054), causing it to move up and down. The mesh may have different implementations, such as a laser drilled metal filter, which may be press fit or threaded.

This idea of developing a fuel pump (100) having the above-mentioned features helps to prevent movement of the plunger seal ring (1054). The fuel pump (100) with the proposed design also helps to eliminate fuel pressure oscillations at the pump inlet, which may be caused by a missing plunger seal ring (1054).

It must be understood that the embodiments explained in the above detailed description are illustrative only and do not limit the scope of the present invention. Any modification of the fuel pump (100) for a vehicle is contemplated and forms part of the present invention. The scope of the invention is limited only by the claims.

Claims

1. A fuel pump (100) for a vehicle, the fuel pump (100) comprising a housing (101) and at least one plunger adapted for reciprocal movement in the housing (101), a fuel inlet (102) in the housing (101) providing a fluid communication path with an inlet valve (103), a leak groove (104) providing a fluid communication path between the inlet valve (103) and a plunger seal chamber (1053), the plunger seal chamber (1053) having a plunger seal ring (1054), characterized in that the fuel pump (100):

an undercut (1051) in the pump housing (101) on top of the plunger seal chamber (1053) enables fluid communication between the leak groove and the plunger gap, a gasket (1052) is positioned between the plunger seal ring (1054) and the undercut (1051).

2. The fuel pump (100) for a vehicle according to claim 1, wherein a mesh is placed inside the undercut (1051).