Fuel injection valve

Abstract

The fuel injection valve (1) according to the invention is characterized in particular in that an improved sealing of the inlet connection piece (7) relative to the receiving opening (12) of the fuel distribution line (4) is achieved. For this purpose, a support ring (25) is arranged on the inlet connection piece (7), which supports the sealing ring (5) on the inlet side, wherein the support ring (25) has a flat lower side (31) for being placed on the shoulder (26) of the inlet connection piece (7) and has a V-shaped placement surface facing the sealing ring (5). According to the invention, the support ring (25) loaded by the sealing ring (5) is provided with such a V-shaped cone placement part for the sealing ring (5), which cone placement part ensures that when the pressure increases, the support ring (25) can be slightly radially displaced radially inwards and radially outwards and thus radial gaps and the extrusion of the sealing ring (5) into the radial gaps are always avoided. The fuel injection valve is particularly suitable for injecting fuel directly into the combustion chamber of an externally ignited internal combustion engine that compresses a mixture.

Description

Technical Field

[0001] The present invention relates to a fuel injection valve for a fuel injection mechanism of an internal combustion engine, in particular to a fuel injection valve for directly injecting fuel into a combustion chamber of the internal combustion engine. Background Art

[0002] Figure 1 , a fuel injection device known from the prior art is shown by way of example, the inlet connection of which is sealed relative to the receiving cup of the fuel distribution line by means of a known sealing ring made of elastomer. The fuel injection device is particularly suitable for use in a fuel injection mechanism of an externally ignited internal combustion engine that compresses a mixture. Such fuel injection valves are well known and are mentioned, for example, in DE 103 59 299 A1.

[0003] DE 102017207091 A1 discloses a fuel injection valve having a conical connecting pipe on the inlet side. The connecting pipe comprises a sealing section, on which an annular sealing element is arranged, which is used to seal against a receiving cup of a fuel distribution line. The annular sealing element surrounds the sealing section in the circumferential direction with respect to the longitudinal axis. In addition, the annular sealing element is supported on the lower end of the sealing section by means of a support ring. At least in the area where the connecting pipe is surrounded by the annular sealing element and the support ring, the sealing section of the connecting pipe is configured to have a circumference that increases along the longitudinal axis, i.e., to have a taper. Summary of the invention

[0004] The fuel injection valve according to the invention has the advantage that an improved sealing of the inlet nozzle relative to the receiving opening of the fuel distribution line is achieved. For this purpose, a support ring is advantageously provided on the inlet nozzle, which supports the sealing ring on the inlet side, wherein the support ring has a flat underside for resting on the shoulder of the inlet nozzle and has a V-shaped support surface facing the sealing ring. According to the invention, the support ring loaded by the sealing ring is provided with such a V-shaped conical support for the sealing ring, which ensures that the support ring can be slightly deflected radially inwards and radially outwards in the event of increased pressure and thus always avoids radial play.

[0005] The measures listed in the preferred specific embodiments result in advantageous developments and improvements of the fuel injection valve according to the invention.

[0006] Advantageously, the support ring has a slightly larger radial extension in the region with the V-shaped placement surface than in the remaining axial extension of the support ring. In this way, the support ring can be introduced into the accommodating space between the fuel injection valve and the connecting pipe with a small radial pressure in this upper region of the support ring. Due to the fluid pressure, two component forces act on the two flanks of the V-shaped placement surface of the support ring via the sealing ring. These forces cause a slight elastic deformation of the support ring, specifically in the radially slightly larger upper region in the thin-walled region below the placement surface, radially inward and outward. This prevents the sealing ring from being squeezed between the support ring and the wall of the accommodating opening or the connecting pipe, because no undesirable gap will occur. Since the support ring is placed flat on the inlet pipe in the axial direction, a certain radial movement of the fuel injection valve in the accommodating opening is still possible. Damage on the fuel injection valve or on the wall of the connecting pipe is ruled out.

[0007] In a particularly advantageous manner, the inlet connection piece can be designed such that the diameter of the inlet-side end flange and the diameter of the inlet connection piece are selected to be of equal size at the height of the support ring. In this way, the support ring can be mounted without problems via the end flange. Ideally, the support ring can have two flanks of the V-shaped support surface extending at different heights, wherein the radially inner flank is lower in the axial direction than the radially outer flank.

[0008] By pressing the radial support disk onto the inlet nozzle of the fuel injection valve, the fuel injection valve can be pre-assembled in a captive manner in the receiving opening of the connecting nozzle of the fuel distribution line. Advantageously, the radial support disk is arranged on the end flange of the inlet nozzle before the sealing ring mounted on the inlet nozzle, as viewed in the flow direction. The radial support disk can thus be mounted very simply and cost-effectively on the inlet nozzle of the fuel injection valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments of the invention are shown in simplified form in the drawings and are explained in more detail in the following description, showing:

[0010] Figure 1 A fuel injection device is shown partially in a known embodiment;

[0011] FIG. 2 shows a first known hydraulic connection in the region of a receiving opening of a fuel distribution line;

[0012] FIG. 3 shows a second known hydraulic connection in the region of a receiving opening of a fuel distribution line;

[0013] Figure 4 A schematic and exaggerated installation situation is shown in the known solution in FIG. 3 under fuel pressure;

[0014] Figure 5 A schematic and exaggerated installation situation is shown in the known solution in FIG. 3 without the influence of fuel pressure;

[0015] Figure 6 Shown is a hydraulic connection in the region of a receiving opening of a fuel distribution line with a supporting ring and a securing ring according to the invention;

[0016] Figure 7 Shows Figure 6 A portion marked as VII in the figure, which has a support ring configured according to the present invention and a sealing element placed thereon;

[0017] Figure 8 The hydraulic connection in the region of the receiving opening of a fuel distribution line with a support ring and a disk-shaped loss prevention device according to the invention is shown;

[0018] Fig. 9 shows a hydraulic connection in the region of a receiving opening of a fuel distribution line with a further support ring according to the invention without the influence of fuel pressure; and

[0019] Fig.10 shows that under fuel pressure, Fig. 9 The hydraulic connection of the support ring in the region of the receiving opening of the fuel distribution line. DETAILED DESCRIPTION

[0020] In order to understand the present invention, Figure 1 A known embodiment of a fuel injection device is described in more detail. Figure 1 1 shows a side view of a valve as an example, which is in the form of an injection valve 1 for a fuel injection mechanism of an externally ignited internal combustion engine that compresses a mixture. The fuel injection valve 1 is part of a fuel injection device. The fuel injection valve 1, which is implemented in the form of a direct injection injection valve for injecting fuel directly into the combustion chamber 16 of the internal combustion engine, is installed with its downstream end in a receiving bore 20 of the cylinder head 9. The sealing ring 2, in particular a sealing ring made of PTFE or PTFE with a filler material, ensures an optimal sealing of the fuel injection valve 1 relative to the wall of the receiving bore 20 of the cylinder head 9.

[0021] On the shoulder 21 of the valve housing 22 (not shown) or on the lower end side 21 ( Figure 1 ) An intermediate element 24 is inserted between a shoulder 23 of receiving bore 20, which is, for example, at a right angle to the longitudinal extension of receiving bore 20. This intermediate element 24 can be used to compensate for manufacturing and assembly tolerances and ensure support free of lateral forces even in the case of a slight tilt of fuel injector 1.

[0022] Fuel injection valve 1 has, at its inlet-side end 3, a plug connection to a fuel distribution line (fuel rail) 4, which is sealed by a sealing ring 5 between a connection piece (rail cup) 6 of fuel distribution line 4, shown in section, and an inlet piece 7 of fuel injection valve 1. Fuel injection valve 1 is inserted into a receiving opening 12 of connection piece 6 of fuel distribution line 4. Connection piece 6 is produced, for example, in one piece from the fuel distribution line 4 itself and has a flow opening 15 of smaller diameter upstream of receiving opening 12, through which flow to fuel injection valve 1 is achieved. Fuel injection valve 1 has an electrical connection plug 8 for electrical contacting in order to actuate fuel injection valve 1.

[0023] The electrical connection plug 8 is connected to an actuator (not shown) via corresponding electrical connections, and by energizing the actuator, a stroke movement of the valve needle can be achieved, thereby enabling the actuation of the valve closing body, which forms a sealing seat together with the valve seat surface. The last-mentioned components are not explicitly shown and can have any well-known structural form. For example, the actuator can be operated electromagnetically, piezoelectrically or magnetostrictively.

[0024] In order to space the fuel injection valve 1 and the fuel distribution line 4 apart from each other in a largely radially force-free manner and to reliably clamp the fuel injection valve 1 in the receiving bore 20 of the cylinder head 9, a clamping device 10 is provided between the fuel injection valve 1 and the connecting pipe 6. The clamping device 10 is implemented as a bow-shaped component, for example, as a stamped and bent part. The clamping device 10 has a partially annular base element 11, from which a clamping bow 13 extends in a bent manner, which in the assembled state abuts against a downstream end face 14 of the connecting pipe 6 on the fuel distribution line 4.

[0025] 2 and 3 show a known hydraulic connection in the region of a receiving opening 12 of a fuel distribution line 4, wherein the structure shown in FIG. 2 is similar to the structure shown in FIG. Figure 1 The structure is the same as that of the fuel injection valve 1. In this embodiment, the inlet pipe 7 of the fuel injection valve 1 is configured as a cylinder. The sealing ring 5 is tensioned between the inner wall of the receiving opening 12 and the inlet pipe 7. In addition, a support ring 25 is provided below the sealing ring 5, which is supported on a shoulder 26 of the inlet pipe 7, for example. Here, the fuel injection valve 1 is radially supported via the support ring 25. In this way, sliding of the sealing ring 5 is excluded. In this regard, the compression of the sealing ring 5 is not affected.

[0026] Compared to the configuration of the hydraulic interface in the region of the receiving opening 12 of the fuel distribution line 4 of FIG. 2 , a conically extending section is provided in the inlet pipe 7 of the fuel injection valve 1 shown in FIG. 3 , which is surrounded by a support ring 25 having an inner opening that is also conically extending and partially surrounded by a sealing ring 5 . Due to the force distribution of the radial force on the conically extending wall of the inlet pipe 7 , in particular the division into axial force components, there is a risk that the sealing ring 5 will slide away from the conical section on one side when the axial force of the support ring 25 is greater than the displacement force of the sealing ring 5 . This sliding may be accompanied by a reduction in the compression of the sealing ring 5 . In this embodiment of the fuel injection valve 1 , the fuel injection valve therefore has a radial support disk 30 on its inlet-side end 3 in the region of the end flange 29 for loss prevention. The radial support disk 30 is implemented as a thin but compact disk that can be made of plastic (e.g. PEEK, PPS, POM) or of metal (e.g. aluminum). Radial support disk 30 is mounted on fuel injection valve 1 axially from above, for example, by means of an auxiliary mandrel. Alternatively, radial support disk 30 can be mounted by means of an expander or similar tool. In this regard, radial support disk 30 is still arranged in front of sealing ring 5 as seen in the flow direction.

[0027] Figure 4 and 5 The figure shows the Figure 1 In known solutions, under fuel pressure ( Figure 4 ) and no fuel pressure ( Figure 5 ) is shown schematically and exaggeratedly in the installation situation under the influence of ). The illustration is not to scale in order to make it clear that due to the tolerance-dependent inclination (denoted by angle γ) of inlet nozzle 7 of fuel injection valve 1 relative to receiving opening 12 of connecting nozzle 6 of fuel distribution line 4, a gap z ( Figure 5 ). Under fuel pressure, the sealing ring 5 moves in the axial direction toward the support ring 25 by hydraulic pressure. The tilting of the inlet pipe 7 of the fuel injection valve 1 may cause the inlet pipe 7 to also slightly move radially on one side until the inlet pipe 7 of the fuel injection valve 1 contacts the inner wall of the receiving opening 12, so that the radial force can be transmitted to the connecting pipe 6 through the fuel injection valve 1. In this case, there is a disadvantageous risk of damaging the connecting pipe 6. In addition, the sealing ring 5 may be damaged when the fuel injection valve 1 is replaced. In addition, the noise characteristics will be deteriorated due to the contact between the fuel injection valve 1 and the inner wall of the receiving opening 12.

[0028] In the same diagrammatic manner as in FIGS. 3 to 5 , Figure 6The hydraulic connection in the region of the receiving opening 12 of the fuel distribution line 4 is now shown with the surrounding support ring 25 according to the invention, which is put onto the connection piece 7 of the fuel injection valve 1 before the above-mentioned radial support disk 30 or another safety device is optimally installed. According to the invention, the support ring 25, which is loaded by the sealing ring 5, is provided with a notch-shaped conical support for the sealing ring 5 with a V-shaped cross section, which can ensure that the sealing ring 5 is slightly deflected radially inwards and radially outwards in the event of increased pressure and thus avoid radial play.

[0029] Figure 7 Shows Figure 6 The part of the support ring 25 with the configuration according to the invention and the sealing ring 5 placed thereon, marked VII in the figure. The support ring 25 is characterized by its V-shaped placement surface 35 for the sealing ring 5. In its upper region facing the sealing ring 5 and having the V-shaped placement surface 35, the support ring 25 has a radial extension that is slightly larger than the remaining axial extension of the support ring 25. In this way, the support ring 25 can already be introduced into the accommodating space between the fuel injection valve 1 and the connecting pipe 6 in this upper region of the support ring 25 with a small radial pressing force. Due to the fluid pressure, two force components act on the two flanks of the V-shaped placement surface 35 of the support ring 25 through the sealing ring 5, and these two force components act on the two flanks of the V-shaped placement surface 35 of the support ring 25. Figure 7 These forces F1 and F2 cause a slight elastic deformation of the support ring 25, specifically in the radially slightly larger upper region, in the radially inner and radially outer thin-walled regions below the support surface 35. In the event of increased fluid pressure, the support ring 25 is additionally radially deflected and squeezed radially inwards and outwards, so that radial play is always avoided, for example in Figure 5 Due to the shape of the support ring 25, two sealing areas 36 and 37 are formed radially inwardly between the support ring 25 and the inlet pipe 7 and radially outwardly between the support ring 25 and the connecting pipe 6. The axial lengths L1 and L2 of the sealing areas 36 and 37 are respectively about 0.2 to 0.8 mm. Figure 4 As explained, radial additional forces can advantageously not be transmitted from fuel injection valve 1 to connection piece 6 of fuel distribution line 4. Support ring 25 rests with its base surface 38 opposite V-shaped support surface 35 on shoulder 26 extending at a right angle to inlet piece 7 of fuel injection valve 1 and is accordingly supported there.

[0030] The support ring 25 is advantageously made of plastic, wherein for example the material PA66 with 30% glass fibers is suitable. Figure 7As shown, in the initial state of the support ring 25 and in the loaded and pressed state, the radial inner and outer sides of the support ring 25 extend from the sealing areas 36 and 37 over at least an axial partial distance that deviates from the horizontal plane by an angle of 90°, thereby forming gap angles α1 and α2 of approximately 2° to 8°. Below the sealing areas 36 and 37, the support ring 25 does not press against the wall of the inlet nozzle 7 or the connecting nozzle 6. The gap widths S1 and S2 of the gap radially inside the support ring 25 and the wall of the inlet nozzle 7 or radially outside the gap between the support ring 25 and the wall of the connecting nozzle 6 are approximately 0.1 to 0.5 mm, respectively. The V-shaped support surface 35 of the support ring 25 does not have to taper in the center, but can be as follows Figure 7 The angle β between the two flanks of the V-shaped support surface 35 of the support ring 25 is approximately 60° to 100°.

[0031] according to Figure 6 The sealing ring 5 is secured by means of a securing ring 41 as an axial assembly securing device, wherein the securing ring 41 is inserted into an annular groove 42 introduced above the sealing ring 5 on the inlet connection piece 7. The retaining ring 41 is designed, for example, in a slotted manner and has a circular or quadrilateral cross section. Alternatively, as Figure 8 As shown, a radial support disk 30 can also be provided for preventing loss at inflow-side end 3 of fuel injection valve 1, which support disk is mounted in the region of end flange 29. In this case, radial support disk 30 is designed as a thin but compact disk.

[0032] Fig. 9 , a hydraulic connection in the region of the receiving opening 12 of a fuel distribution line 4 with a further support ring 25 according to the invention without the influence of fuel pressure is shown. This embodiment is characterized in that the diameter D2 of the end flange 29 of the inlet connection piece 7 and the diameter D1 of the inlet connection piece 7 are selected to be identical at the height of the support ring 25. In this way, the support ring 25 can be mounted without problems via the end flange 29. In this embodiment, the support ring 25 has two flanks, for example a V-shaped support surface 35, extending at different heights, wherein the radially inner flank is lower in the axial direction than the radially outer flank. It is advantageous if the sealing ring 5 is introduced, as shown in the figure, into a receiving groove 43 with a smaller diameter D3 on the inlet connection piece 7, which is slightly recessed relative to the end flange 29 and the receiving area (D1, D2) for the support ring 25.

[0033] Fig.10 shows that under fuel pressure, Fig. 9The hydraulic connection in the region of the receiving opening 12 of the fuel distribution line 4 of the support ring 25 is schematically shown hereby that the sealing ring 5 under fuel pressure can move slightly with its material from the radial inside via the radially inner flanks of the V-shaped support surface 35 of the support ring 25 between the two flanks and into the support ring.

Claims

1. A fuel injection valve (1) for a fuel injection mechanism of an internal combustion engine, the fuel injection valve comprising: an actuator, by energizing the actuator, a stroke movement of a valve needle can be achieved, thereby enabling the operation of a valve closing body, the valve closing body forming a sealing seat together with a valve seat surface; an inlet pipe (7) on the inlet side for fuel supply, wherein: A sealing ring (5) surrounding the inlet pipe (7) is arranged on the inlet pipe, wherein the sealing ring (5) is supported by a support ring (25), the support ring having a placement surface (35) for the sealing ring (5), the placement surface facing the sealing ring (5) and having a V-shaped cross-section, wherein the V-shaped placement surface (35) of the support ring (25) has two side wings, and when hydraulic pressure acts directly on the sealing ring (5), two component forces act on the two side wings via the sealing ring (5).

2. The fuel injection valve according to claim 1, characterized in that: In the radially inner and radially outer thin-walled regions below the placement surface (35), a small elastic deformation of the support ring (25) in the radial direction can be achieved.

3. The fuel injection valve according to claim 2, characterized in that: In the extruded state, two sealing areas (36, 37) are formed radially inwardly between the support ring (25) and the inlet pipe (7) and radially outwardly between the support ring (25) and the connecting pipe (6), and the axial lengths (L1, L2) of the two sealing areas are both 0.2 mm to 0.8 mm.

4. The fuel injection valve according to claim 3, characterized in that: The radial inner side and the radial outer side of the support ring (25) extend from the two sealing areas (36, 37) at least over an axial partial distance at an angle, so that the support ring (25) is spaced apart from the wall of the inlet nozzle (7) and from the wall of the connecting nozzle (6) below the two sealing areas (36, 37).

5. The fuel injection valve according to claim 4, characterized in that: The gap width (S1, S2) of the gap radially inwardly between the support ring (25) and the wall of the inlet connector (7) or the gap radially outwardly between the support ring and the wall of the connection connector (6) is 0.1 to 0.5 mm.

6. The fuel injection valve according to any one of claims 1 to 5, characterized in that The angle (β) between the two flanks of the V-shaped placement surface (35) of the support ring (25) is 60° to 100°.

7. The fuel injection valve according to any one of claims 1 to 5, characterized in that The V-shaped support surface (35) of the support ring (25) is rounded in the middle.

8. The fuel injection valve according to any one of claims 1 to 5, characterized in that The radially inner flanks of the V-shaped supporting surface (35) of the support ring (25) are designed to be lower in their axial extension than the radially outer flanks of the V-shaped supporting surface (35) of the support ring (25).

9. The fuel injection valve according to any one of claims 1 to 5, characterized in that A securing ring (41) is arranged at the inlet-side end of the inlet connector (7) for preventing the sealing ring (5) from being lost in the assembled state.

10. The fuel injection valve according to any one of claims 1 to 5, characterized in that A radial support disk (30) is arranged at the inlet-side end of the inlet connector (7) for preventing the fuel injection valve (1) from being lost in the installed state.

11. The fuel injection valve according to any one of claims 1 to 5, characterized in that The support ring (25) is made of plastic.

12. The fuel injection valve according to any one of claims 1 to 5, characterized in that The fuel injection valve (1) is used to inject fuel directly into a combustion chamber of an internal combustion engine.

13. The fuel injection valve according to claim 11, characterized in that The plastic is polyamide PA66.

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