VALVE FOR METERING A FLUID, CONNECTION PIECE FOR A VALVE, AND FUEL INJECTION SYSTEM

Abstract

A connection piece for a valve, which is for metering a fluid, includes a sealing section, on which at least one annular sealing element is situated. The annular sealing element circumferentially surrounds the sealing section with respect to a longitudinal axis. In the connection piece, at least one support ring is situated on the sealing section, the support ring at least partially circumferentially surrounds the sealing section with respect to the longitudinal axis, the sealing section is configured, at least in one area along the longitudinal axis, in which the support ring surrounds the sealing section at least during operation, to have a circumference increasing in a direction along the longitudinal axis, and the support ring and the sealing section are configured so that, during operation, the support ring is displaceable in the direction in relation to the sealing section due to a fluid pressure of the fluid.

Claims

1-10. (canceled)

11. A connection piece for a valve for metering a fluid, comprising: a sealing section, on which at least one annular sealing element is situated, the annular sealing element circumferentially surrounding the sealing section with respect to a longitudinal axis; wherein at least one support ring is situated on the sealing section, the support ring at least partially circumferentially surrounds the sealing section with respect to the longitudinal axis, the sealing section is configured, at least in one area along the longitudinal axis, in which the support ring surrounds the sealing section at least during operation, to have a circumference increasing in a direction along the longitudinal axis, and the support ring and the sealing section are configured so that, during operation, the support ring is displaceable in the direction in relation to the sealing section due to a fluid pressure of the fluid.

12. The connection piece of claim 11, wherein the sealing element is acted upon, during operation, in the direction against the support ring due to the fluid pressure of the fluid, and/or the sealing element is supported on the support ring at least during operation.

13. The connection piece of claim 11, wherein the sealing section has an outer diameter increasing along the longitudinal axis at least in the area and/or the sealing section is configured having a conical lateral surface at least in the area.

14. The connection piece of claim 11, wherein the support ring includes a fiber reinforcement which increases a tensile strength of the support ring at least in a circumferential direction about the longitudinal axis.

15. The connection piece of claim 11, wherein the direction, in which the sealing section has a circumference increasing along the longitudinal axis, is oriented counter to a joining direction, in which an insertion along the longitudinal axis into a receiving space of a receiving piece takes place.

16. The connection piece of claim 15, wherein the support ring includes a support surface resting against the sealing element, and/or a receiving piece assigned to the connection piece, and the sealing element, the support ring, and an inner surface of the receiving piece, which is cylinder shell-shaped at least in the area of the sealing element and of the support ring, are matched to each other so that, during operation, the support ring is pressed between the sealing section and the inner surface of the receiving piece, due to the fluid pressure, to form a secondary seal.

17. The connection piece of claim 11, wherein the sealing element includes an elastically deformable sealing element and/or the sealing element is in the shape of an O-ring.

18. A valve for metering a fluid, comprising: a connection piece, via which the fluid is feedable; wherein the connection piece includes a sealing section, on which at least one annular sealing element is situated, the annular sealing element circumferentially surrounding the sealing section with respect to a longitudinal axis, and wherein at least one support ring is situated on the sealing section, the support ring at least partially circumferentially surrounds the sealing section with respect to the longitudinal axis, the sealing section is configured, at least in one area along the longitudinal axis, in which the support ring surrounds the sealing section at least during operation, to have a circumference increasing in a direction along the longitudinal axis, and the support ring and the sealing section are configured so that, during operation, the support ring is displaceable in the direction in relation to the sealing section due to a fluid pressure of the fluid.

19. A fuel injection system for mixture-compressing a spark-ignition internal combustion engine, comprising: at least one fuel-conveying component which includes a receiving piece, and at least one valve, which includes a fuel injection valve, the connection piece of the valve being insertable along the longitudinal axis into the receiving piece; wherein the valve includes a connection piece, via which the fluid is feedable, wherein the connection piece includes a sealing section, on which at least one annular sealing element is situated, the annular sealing element circumferentially surrounding the sealing section with respect to a longitudinal axis, and wherein at least one support ring is situated on the sealing section, the support ring at least partially circumferentially surrounds the sealing section with respect to the longitudinal axis, the sealing section is configured, at least in one area along the longitudinal axis, in which the support ring surrounds the sealing section at least during operation, to have a circumference increasing in a direction along the longitudinal axis, and the support ring and the sealing section are configured so that, during operation, the support ring is displaceable in the direction in relation to the sealing section due to a fluid pressure of the fluid.

20. The fuel injection system of claim 19, wherein the receiving piece includes an at least partially cylindrical receiving space, the sealing element, in the assembled state, rests outwardly against a cylinder shell-shaped inner surface of the receiving piece and inwardly against the sealing section, and the sealing element is acted upon, during operation, by a fuel pressure along the longitudinal axis in the direction counter to the increasing circumference of the sealing section.

21. The connection piece of claim 11, wherein the valve for metering the fluid includes a fuel injection valve of an internal combustion engine.

22. The valve of claim 18, wherein the valve for metering the fluid includes a fuel injection valve of an internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows a fuel injection system including a valve which includes a connection piece in extracts of a schematic sectional representation according to an exemplary embodiment of the present invention.

[0017] FIG. 2 shows in extracts a representation of a sealing element and a support ring of the valve represented in FIG. 1, in a profile view.

[0018] FIG. 3 shows in extracts a representation of the fuel injection system shown in FIG. 1, according to one further exemplary embodiment.

DETAILED DESCRIPTION

[0019] FIG. 1 shows a fuel injection system 1 including a valve 2 which includes a connection piece 3, in extracts of a schematic sectional representation according to one exemplary embodiment. Valve 2 may be configured, in particular, as a fuel injection valve 2. One application is a fuel injection system 1, in which such fuel injection valves 2 are configured as high-pressure injection valves 2 and are utilized for the direct injection of fuel into assigned combustion chambers of the internal combustion engine. Liquid or gaseous fuels may be utilized as fuel in this case.

[0020] Connection piece 3 is configured as a connection fitting 3 in this exemplary embodiment and is integrated into valve 2 in a suitable way. Connection piece 3 includes a shoulder 4, on which a mounting bracket or the like may engage, for example, in the assembled state, in order to connect valve 2 to a receiving piece 5. Receiving piece 5 is configured as a cup 5 in this exemplary embodiment.

[0021] Fuel injection system 1 includes a fuel-conveying component 6 which is configured as a fuel distributor 6, in particular, as a fuel rail 6, in this exemplary embodiment. Cup 5 may be part of fuel-conveying component 6 in this case.

[0022] During operation, fuel is conveyed from a tank 8 into fuel distributor 6 via one or multiple pumps 7. Fuel distributor 6 then distributes the fuel to fuel injection valves 2 which are connected to corresponding cups 5. In this exemplary embodiment, only fuel injection valve 2 and cup 5 are represented, for the sake of simplicity of the representation. The distribution of the fuel is schematically illustrated in this case via lines 8, 9, and 10.

[0023] Cup 5 includes an at least partially cylindrical receiving space 15 which includes a cylinder shell-shaped inner surface 16 at least in one portion. For the purpose of installation, fuel injection valve 2 is inserted into cup 5 in a joining direction 17 along a longitudinal axis 18. As a result, a sealing section 19 of connection piece 3, viewed along longitudinal axis 18, enters cylinder shell-shaped inner surface 16 along longitudinal axis 18.

[0024] Connection piece 3 includes a tubular, metallic base body 20 including a through-hole 21 which is configured as a stepped hole 21 in this exemplary embodiment. Moreover, connection piece 3 includes a sealing element 22, which is configured as a sealing ring 22, and a support ring 23. Support ring 23 may be configured as a circumferentially closed support ring 23.

[0025] Sealing element 22 is configured as an O-ring. A profile of sealing element 22 in the relaxed state may be configured to be circular, as illustrated in FIG. 2.

[0026] Sealing section 19 is formed on base body 20 and extends across an area 19. In area 19, sealing section 19 includes a conical lateral surface 24. Conical lateral surface 24 is the lateral surface 24 of a truncated cone in this case. Conical lateral surface 24 tapers in joining direction 17 in this case. This means, conical lateral surface 24 expands in a direction 11 which is counter to joining direction 17 in this exemplary embodiment. Therefore, in this exemplary embodiment, sealing section 19 has an outer diameter 25 increasing along longitudinal axis 18 counter to joining direction 17. As outer diameter 25 increases, a circumference on sealing element 22 also increases along longitudinal axis 18. In this exemplary embodiment, the circumference results from the circle having outer diameter 25 which increases in sealing section 19 counter to joining direction 17.

[0027] Therefore, sealing section 19 of base body 20 of connection piece 3 is configured having a circumference increasing in direction 11 along longitudinal axis 18 in area 19 along longitudinal axis 18, in which annular sealing element 22 surrounds sealing section 19.

[0028] Sealing element 22 is pressed against support ring 23 upon insertion of connection piece 3 into cup 5. As a result, sealing element 22 is positioned after insertion into cup 5. Moreover, an elastic deformation of sealing element 22 on conical lateral surface 24 takes place. As a result, sealing element 22 is also pressed against cylinder shell-shaped inner surface 16 of cup 5. When fuel is subsequently conveyed via line 8 into an interior space 26 of cup 5, sealing element 22 is acted upon by the pressure of the fuel. A further deformation of sealing element 22 may result. This results in a sealing effect which is self-reinforcing as a result of the pressure and may be referred to as a primary seal.

[0029] In this exemplary embodiment, support ring 23 includes a support surface 30 resting against sealing section 19. Support surface 30 is likewise configured to be conical in this case, where the same opening angle may be predefined as for conical lateral surface 24. Due to fluid pressure P which, in this exemplary embodiment, is represented by fuel pressure P of the fuel, the support element is displaced, during start-up, in direction 11 in relation to sealing section 19, so that the sealing element circumferentially expands, whereby the sealing element rests against inner surface 16 during operation. Therefore, a secondary seal results due to support ring 23. Moreover, an end 31 for sealing section 19 along longitudinal axis 18 is predefined by support ring 23. Sealing element 22 is then supported on end 31 of sealing section 19 with the aid of support ring 23.

[0030] FIG. 2 shows in extracts a representation of sealing element 22 and of support ring 23 of valve 2 of fuel injection system 1 of the exemplary embodiment, which is represented in FIG. 1, in a profile view. In this case, sealing element 22 is represented in the initial state, i.e., without elastic deformation. Sealing element 22 has a circular profile in this case. During installation, sealing element 22 is deformed on an inner side 32 by sealing section 19 of base body 20. Moreover, sealing element 22 is pressed, on an outer side 33, against cylinder shell-shaped inner surface 16 of cup 5. Therefore, sealing element 22 is also deformed in the area of outer side 33.

[0031] During operation, sealing element 22 is acted upon by the pressure of the fuel on a fuel side 34 facing interior space 26 filled with fuel. In this case, sealing element 22 is supported, via its support side 35, on a support surface 36 of support ring 23. Support surface 36 may be oriented perpendicularly to longitudinal axis 18 in this case.

[0032] FIG. 3 shows in extracts a representation of the fuel injection system shown in FIG. 1, according to one further exemplary embodiment. In this exemplary embodiment, an area 19 of sealing section 19, in which sealing section 19 has a conical configuration, is predefined along longitudinal axis 18 in such a way that a radial expansion of support ring 23 is made possible due to an application of fluid pressure P, in particular, fuel pressure P, on support ring 23 and the resultant displacement of support ring 23 in direction 11 along sealing section 19 which is conical there. Area 19 is situated in area 19 or is congruent with area 19. Area 19 along longitudinal axis 18, in which support ring 23 surrounds sealing section 19 at least during operation, is therefore configured having a circumference increasing in a direction 11 along longitudinal axis 18.

[0033] Moreover, support ring 23 and sealing section 19 are configured in such a way that, during operation, support ring 23 is displaceable in direction 11 in relation to sealing section 19 due to fluid pressure P of the fluid. This means, a degree of freedom of the support ring in direction 11 is not (completely) limited even in its end position assumed during operation, as would be the case, for example, with a support surface of a shoulder oriented perpendicularly to longitudinal axis 18. Due to sealing element 22 being acted upon by fluid pressure P, support ring 23 is therefore acted upon axially in direction 11, whereupon, due to the conical sealing section 19 there, support ring 23 is pressed into an annular gap 37, which has a wedge-shaped profile, between inner surface 16 and sealing section 19. In so doing, the support ring is pressed from the inside radially against inner surface 16 and from the outside radially against sealing section 19. Therefore, a secondary seal may be formed.

[0034] The geometry of gap 37 is predefined by the geometry of sealing section 19 and inner surface 16 of receiving piece 5. The geometries of receiving piece 5, sealing section 19, and support ring 23, as well as the inner configuration and the material or materials of support element 23, are matched to each other and are predefined in such a way that support element 23 may expand to the desired extent but does not tear and may not be extruded through gaps which may remain. As a result, adaptations to the configuration which results and, if necessary, deviates slightly from the structurally predefined configuration, may take place in an optimal way even in the case of a slanted position which may result and in the case of an axial offset which may result, whereby the secondary seal is formed in a reliable way.

[0035] The interior configuration and the material or materials of support element 23 may be implemented, in an advantageous way, with the aid of a temperature-resistant support ring material, such as polyamide, including glass fibers contained in the support ring material, the glass fibers being oriented in the circumferential direction due to the manufacturing process, so that high tensile stresses may be absorbed during operation.

[0036] The secondary seal imparted by way of support element 23 is suitable for demonstrably reducing a leakage which is made possible, if necessary, due to the permeability of sealing element 22 and which may be due to a boundary surface leakage at sealing element 22, in particular, at low temperatures, for example, at temperatures below the limiting temperature of sealing element 22 designated as TRIO.

[0037] The present invention is not limited to the described exemplary embodiment.