DE102022208197A1 - Fuel injection system with a fuel rail - Google Patents

Abstract

The present invention proposes a fuel injection system with a fuel rail (10) for an internal combustion engine, comprising: a tubular body (20) extending along a longitudinal axis (L) with a longitudinal channel (30) for receiving, in use, of pressurized fuel; a plurality of injector seats (50) disposed on the tubular body (20); a first bore (80) formed on the tubular body (20) for opening a main bore (40) in the tubular (20) body; a plug (90) for plugging the first bore (80) firmly. The plug (90) includes a first cutout (94) formed at a plug end (92) in flow communication with the main bore (40) of the tubular body (20).

Description

technical field

The present invention relates to a fuel injection system with a fuel rail for an internal combustion engine according to the preamble of claim 1.

Background of the Invention

A fuel rail is part of a fuel injection system and is used to deliver fuel to the fuel injectors of an internal combustion engine. During operation, fuel is injected at high pressure into a tubular body of the fuel rail and is transported into the internal combustion engine's cylinders via fuel injectors. Forged fuel rails are preferred in the art for reliability when operating at higher pressures. In the forging process, injector mounts, connectors, or support portions of the fuel rail are often formed from the material of the tubular body of the fuel rail.

As a prior art publication in the technical field of the invention, reference may be made to CN212406922U which includes a forged GDI (Gas Direct Injection) fuel rail with a brazed and plugged main pipe. It comprises a fuel rail main body, a fuel injector seat plug block and a tip; the fuel injector seat stuffing block and the end piece are brazed together, and the end piece is brazed to the oil pipe body.

Brief description of the invention

The object of the present invention is to reduce pressure loads at connection areas of the plug with the fuel rail.

The present invention proposes a fuel injection system with a fuel rail for an internal combustion engine, comprising: a tubular body, extending along a longitudinal axis, with a longitudinal channel for receiving, in use, pressurized fuel; a plurality of injector seats arranged on the tubular body; a first bore formed on the tubular body to open a main bore in the tubular body; a plug for plugging the first bore firmly. The plug includes a first cutout formed at a plug end in flow communication with the main bore of the tubular body. Thus, the compressive load cannot only push the plug in one direction, and the load distribution occurs more homogeneously on the plug and stress is also distributed to the other area of the plug, not just the welded area, since the fluid flows to the first cutout. Thus, the life of the welded portion is improved.

In one possible embodiment of the invention, the stopper has a second cutout formed on a stopper body as a continuation of the first cutout. Thus, the fluid pressure load is applied to the walls of the first cutout with the second cutout. Thus, the compressive load cannot only push the plug in one direction, and the load distribution occurs more homogeneously on the plug.

In another possible embodiment of the invention, the first cutout and the second cutout have a step between them. So a compression load compensation is achieved.

In a further possible embodiment of the invention, the first section and the second section have a gradient between them. So a compression load compensation is achieved.

In a further possible embodiment of the invention, the tubular body is designed as a forged tubular body. Thus, a more reliable tubular body is obtained.

In a further possible embodiment of the invention, the plurality of injection valve receptacles are formed in one piece with the tubular body by a forging process and are made of the same material as the tubular body. Thus, a more reliable injector seat design on the tubular body is obtained.

In a further possible embodiment of the invention, the first bore has an orifice part which is open to the main bore. A joint or weld area for the plug at the first bore is thus obtained.

In a further possible embodiment of the invention, the plug has a chamfered surface and is welded from the chamfered surface to the mouth part of the first bore. Thus, a welding area of the plug to the plug is obtained.

character list

• 1 Figure 12 illustrates a perspective view of a fuel rail according to the present invention with fuel rails and with plugs on holes and showing an AA cross section line.
• 2 represents the AA cross-section line of 1 12 and showing the plug, first bore, main bore, injector receiving hole, longitudinal passage and the interior of the fuel rail.
• 3 exhibits detail B 2 and shows stress points between the plug and the fuel rail.
• 4 Figure 12 shows a perspective view of a stopper according to the present invention.
• 5 puts one half of the plug in 4 in cross section.
• 6 Figure 12 shows a stopper in perspective according to the prior art.
• 7 puts one half of the plug in 6 in cross section.

Detailed description of the figures

The present invention proposes a fuel injection system with a fuel rail (10), in particular a common rail for a plurality of fuel injectors which are attached via injector seats (50), a plurality of fuel injectors which are attached to the fuel rail (10) in the common rail system are attached, for an internal combustion engine.

In particular, the fuel rail (10) comprises a tubular body (20) extending along a longitudinal axis (L) having an internal longitudinal passage (30) for receiving, in use, pressurized fuel; a plurality of injector seats (50) integrally formed on said tubular body (20) and made of the same material as said tubular body (20); a plurality of support members (100) integrally formed on the tubular body (20) for securing to a component of the fuel injection system.

With reference to 1 the tubular body (20) is formed with a plurality of injection valve receptacles (50), a plurality of support members (100) and a longitudinal channel (30) formed along the longitudinal axis (L). The tubular body (20) is formed by a forging process. The injection valve seats (50) and the support members (100) extend parallel to one another. Likewise, the injector seats (50) and the support members (100) extend perpendicularly to the longitudinal axis (L) of the tubular body (20) in the same plane.

Forged fuel rails (10) are used to deliver fuel from a high pressure pump to fuel injector systems. Forged fuel rails (10) are made by a forging process using only a metal body. To create the internal holes of the forged fuel rails (10), machining is used to drill the longitudinal channel (30) and injector receiving holes (70). During this machining process some holes remain open and these holes must be plugged using welded plugs (90). Furthermore, the vias may be formed by an electrochemical machining (ECM) process, more specifically, the interface portions of the vias may be formed by the ECM.

2 represents the AA cross-section of 1 10 showing the plug (90), the holes and bores and the interior of the fuel rail (10). As can be seen from the cross section, the longitudinal channel (30) of the tubular body (20) extends nearly along the tubular body (20). The fuel rail (10) is open at one end to receive fuel or a fluid to the interior of the fuel rail (10) and is also closed at the other end by a plug (90). First, a first bore (80) is formed by drilling in the tubular body (20), and then a main bore (40) is formed by inserting a drill from the first bore (80) and leading the main bore (40) to the longitudinal channel (30 ) towards open. The main bore (40) is formed almost perpendicularly to the longitudinal channel (30) and extends to the center of the longitudinal channel (30). However, the drill center points mentioned may be changed accordingly. Thus, the first bore (80) is formed, and after this process, the main bore (40) is formed as a continuation of the first bore (80). The first bore (80) is like a dimple shape and is blocked by applying a plug (90).

The injector seat (50) includes a seat recess (60) for attachment to an end of the fuel injector (not shown in the figures). An injector receiving hole (70) is formed by inserting a drill from the receiving recess (60) to the inside. The injector receiving hole (70) is formed to communicate with the main bore (40).

3 exhibits a detail B 2 Illustrating the stress points of the plug (90) on the fuel rail (10). The tubular body (20) of the fuel rail (10) has a number of cylindrical first bores (80). The first bore (80) has an orifice part (83) which is open to the main bore (40).

4 Figure 12 shows a plug (90) in a perspective view according to the present invention. 5 put one half of the plug (90) in 4 in cross-section. The plug (90) comprises a plug body (91), a plug end (92) formed on the plug body (91) in a frusto-conical cross-section. The plug end (92) has a chamfered surface (93) which contacts the mouth portion (83) of the first bore (80). The welding process is performed on the chamfered surface (93) of the plug (90). The plug (90) has a first cutout (94) formed in the plug body (91) and a second cutout (95) formed in the plug end (92).

6 Figure 12 shows a plug (90) in a perspective view according to the prior art. 7 put one half of the plug (90) in 6 in cross section. How off 6 and 7 As can be seen, the prior art plug (90) has a rigid and smooth design without any cutouts. The prior art plug (90) has a planar surface (96) formed on the plug end (92) that contacts the fluid (ie fuel) in the main bore (40).

In a more detailed explanation of the invention, a fuel injection system comprises a fuel rail (10), in particular a common rail for supplying fluid to a plurality of fuel injection valves (not shown in the figures), which are fastened via injection valve receptacles (50), a plurality of fuel injection valves, attached to the fuel rail (10) in the common rail system. The injector seats (50) and the support members (100) are integrally formed on the tubular body (20) of the fuel rail (10). The fuel or some type of fluid is supplied from a tip of the tubular body (20) and fluid flows from the longitudinal channel (30) to the injector seats (70) and thus through the interior of the fuel injector. The first bore (80) is created to open the main bore (40), in other words to open into and open the main bore (40). Thus, if the main bore (40) is drilled or reached after this process, the first bore (80) should be plugged. One method of plugging the first bore (80) is plugging the first bore (80) using a plug (90), and the plug (90) is pushed from a plug end (92) of the plug (90) to the mouth portion (83 ) of the tubular body (20) welded. Welded plugs (90) must be reliable over the life of the product. And the potentially critical area with welded plugs (90) is the welded area, due to fuel pressure loading during service life. Pressure changes at the welded area can generate the fatigue cracks on the product before the end of the product's life. The fuel injection system is a safety critical component as fuel leakage can result in a burning car.

To increase the life of the fuel injection system, modifications are made to the plug (90) to reduce the stress transferred to the component due to the compressive load of the unit.

Material connection is provided by the welded portion of the plug (90). The plug (90) is welded from the chamfered surface (93) to the mouth portion (83) of the fuel rail (10).

During operation of the fuel injection system, fluid in the longitudinal passage (30) and also in the main bores (40) applies a compressive load to contact surfaces. In the prior art plug (90) design, the contact surface is the planar surface (96) of the plug (90). The compressive load pushes the plug (90) in one direction and very close to the welded area. This transfers stress peaks to the welded area. There are two main stress points on the welded surfaces due to the noted compressive load on the plug (90), a first stress point (81) and a second stress point (82) located on the chamfered surface (93) of the plug (90). In simulation measurements, the graphs show two very different stress values. One value is 498 MPa at the first stress point (81) and the other value is 180 MPa at the second stress point (82) on the plug (90) in the prior art. This indicates a high stress level at the first stress point (81) and a low stress level at the second stress point (82) at the plug (90) and at the connection area of the plug (90) to the tubular body (20). Thus, there is an uneven load distribution.

In the present invention, graphs in simulation measurements show a homogeneous stress value. One value is 353 MPa at the first stress point (81), and the other value is 300 MPa at the second stress point (82) on the plug (90) in the present invention. The compression load can not push the plug (90) in only one direction, and the load distribution is more homogeneous on the plug (90), and also the stress is distributed to the other area of the plug (90), not only the welded area, since the fluid flows to the first cutout (94) or the first cutout (94) with the second cutout (95). Thus, the durability of the welded portion is improved.

With the first cutout (94) and the second cutout (95), the contact area of the pressurized fluid on the plug (90) is increased. When the contact area is increased, the compressive load is distributed almost homogeneously. Thus, the load placed on the plug (90) by the fluid flow is evenly distributed. Thus, the pressure transmitted via the fluid flow creates less stress at the interface of the plug (90) with the tubular body (20). This means extended product life under pressure, temperature and vibration loads.

In addition, the second cutout (95) is designed as a continuation of the first cutout (94). A gradual or gradual transition between the first cutout (94) and the second cutout (95) provides compression load compensation. Thus, the stress against the dynamic loads on the welded portion of the plug (90) is reduced.

Reference List

10

fuel rail

20

tubular body

30

longitudinal channel

40

main bore

50

fuel injector mount

60

recording deepening

70

fuel injector receiving hole

80

First drilling

81

First tension point

82

Second point of tension

83

muzzle part

90

Plug

91

plug body

92

plug end

93

Chamfered surface

94

First cut

95

Second excerpt

96

planar surface

100

support member

L

longitudinal axis

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• CN 212406922 U [0003]

Claims (8)

A fuel injection system with a fuel rail (10) for an internal combustion engine, comprising: a tubular body (20) extending along a longitudinal axis (L) having a longitudinal passage (30) for receiving, in use, pressurized fuel; a plurality of injector seats (50) disposed on the tubular body (20); a first bore (80) formed on the tubular body (20) for opening a main bore (40) in the tubular (20) body; a plug (90) for plugging the first bore (80) firmly; characterized in that the plug (90) includes a first cutout (94) formed at a plug end (92) in flow communication with the main bore (40) of the tubular body (20). fuel injection system claim 1 wherein the plug (90) has a second cutout (95) formed on a plug body (91) as a continuation of the first cutout (94). fuel injection system claim 2 wherein the first cutout (94) and the second cutout (95) have a step therebetween. fuel injection system claim 2 wherein the first portion (94) and the second portion (95) have a gradient therebetween. A fuel injection system as claimed in any preceding claim, wherein the tubular body (20) is formed as a forged tubular body. fuel injection system claim 5 wherein the plurality of injector seats (50) are formed integrally with the tubular body (20) by a forging process and are made of the same material as the tubular body (20). A fuel injection system as claimed in any preceding claim, wherein the first bore (80) has an orifice portion (83) which opens to the main bore (40). fuel injection system claim 7 wherein the plug (90) has a chamfered surface (93) and is welded from the chamfered surface (93) to the mouth portion (83) of the first bore (80).

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