CN114382624A

CN114382624A - Fuel injection valve

Info

Publication number: CN114382624A
Application number: CN202111231809.1A
Authority: CN
Inventors: R·克罗默; D·普费尔勒; D·施米德尔
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-10-22
Filing date: 2021-10-22
Publication date: 2022-04-22
Also published as: DE102020213356A1

Abstract

The invention relates to a fuel injection valve (1) according to the invention, which is characterized in that, in particular, an improved sealing of the inflow socket (7) relative to the receiving opening (12) of the fuel distributor line (4) is achieved. For this purpose, a support ring (25) is arranged on the inflow socket (7), said support ring engaging the inflow-side sealing ring (5) from below. The fuel injection valve (1) also has a plastic injection molding (18) that forms at least part of the valve housing (22). According to the invention, a support ring (25) which grips the sealing ring (5) from below is positioned on the fuel injection valve (1) in such a way that it rests directly on an upper end side (28) of an annular support element (32) facing the sealing ring (5), said annular support element being fastened to the inflow nipple (7). The fuel injection valve is particularly suitable for injecting fuel directly into the combustion chamber of a mixture-compressing, spark-ignition internal combustion engine.

Description

Fuel injection valve

Technical Field

The invention relates to a fuel injection valve.

Background

Fig. 1 shows an exemplary fuel injection system known from the prior art, whose inflow socket is sealed off from the receiving cup of the fuel distributor line by means of a known sealing ring made of an elastomer. The fuel injection device is particularly suitable for use in fuel injection systems of mixture-compressing, spark-ignition internal combustion engines. Such a fuel injection valve is known in large numbers, for example from DE 10359299 a 1.

DE 102017207091 a1 discloses a fuel injection valve which has a conical attachment socket on the inflow side. The attachment socket comprises a sealing section on which an annular sealing element is arranged for sealing against a receiving cup of the fuel distributor line. The annular sealing element circumferentially surrounds the sealing section with respect to the longitudinal axis. Furthermore, the annular sealing element is supported on the lower end of the sealing section by means of a support ring. The sealing section of the attachment socket is formed with a circumference that increases along the longitudinal axis, i.e. is formed with a taper, at least in the region of the annular sealing element and the support ring that surround the attachment socket.

Disclosure of Invention

The invention relates to a fuel injection valve for a fuel injection system of an internal combustion engine, in particular for injecting fuel directly into a combustion chamber of the internal combustion engine, the fuel injection valve has an actuator, the reciprocating motion of the valve needle can be realized through the excitation of the actuator, this enables actuation of a valve-closing body which forms a sealing seat together with a valve seat surface, the fuel injection valve having an inflow-side inflow connection for a fuel supply, wherein a sealing ring is arranged on the inflow nipple surrounding the inflow nipple and the fuel injection valve has a plastic injection coating forming at least part of a valve housing, wherein a support ring engages the sealing ring from below, which support ring in turn rests directly on the upper end side of an annular support element fastened to the inflow socket, facing the sealing ring.

The fuel injection valve of the present invention has the following advantages: an improved sealing of the inflow nipple with respect to the receiving opening of the fuel distributor line is achieved. For this purpose, a support ring is advantageously provided on the inflow socket, which engages the inflow-side sealing ring from below, wherein the support ring rests directly on the upper end face of an annular support element facing the sealing ring, which is fastened to the outer circumference of the inflow socket.

A particular advantage arises in the case of so-called long valves, which, due to their particular installation in the cylinder head, must have a large axial length. According to the invention, an additional metal extension of the inflow socket can be omitted. The inflow socket can therefore be embodied with a relatively thin wall over its entire axial extension, while the required radial component placement for the support ring is provided only by small and compact support elements.

The measures cited in the preferred embodiments make it possible to achieve advantageous embodiments and improvements of the fuel injection valve proposed in the invention.

Advantageously, the upper end of the annular support element is embodied in a conically obliquely extending manner, wherein the support ring also has a conical inner side pointing toward the upper end of the plastic injection mold, in order to ensure an optimal contact of the support ring against the annular support element and to ensure a desired force introduction.

It is particularly advantageous if the support ring has a V-shaped resting 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 seat for the sealing ring, which is responsible for allowing a slight radial deflection of the sealing ring radially inwards and outwards when the pressure increases and thus always avoiding radial play.

Advantageously, the support ring has a slightly larger radial extent in the region of the V-shaped bearing surface than the remaining axial extension of the support ring. In this way, the support ring can already be introduced into the receiving space between the fuel injection valve and the attachment stub by means of the small radial pressure in this upper region of the support ring. Due to the fluid pressure, two force components act via the sealing rings on both sides of the V-shaped bearing surface of the support ring. These forces lead to a slight elastic deformation of the support ring, namely in the radially inner and radially outer thin-walled regions below the contact surface in the upper region, which is slightly larger in the radial direction. This prevents the sealing ring from possibly being squeezed out between the support ring and the wall of the receiving opening or of the attachment stub, since no undesired gaps occur.

The annular support element is advantageously a metal component and can be produced simply and cost-effectively by turning, stamping or drawing, which is also suitable when the annular support element is embodied as a stamped and bent part.

Drawings

Embodiments of the invention are illustrated in simplified form in the accompanying drawings and set forth in more detail in the description below. The figures show:

figure 1 shows in part a fuel injection apparatus in a known embodiment,

figure 2 shows the known hydraulic interface in the region of the receiving opening of the fuel distributor line,

FIG. 3 shows a first hydraulic connection in the region of a receiving opening of a fuel distributor line with a support ring arranged according to the invention on a fuel injection valve and an annular first support element,

FIG. 4 shows a second hydraulic connection with a support ring according to the invention arranged on the fuel injection valve in the region of the receiving opening of the fuel distributor line,

figures 5A and 5B are plan views and cross-sections of the annular second support element according to figure 4,

figures 6A and 6B are top views and cross-sections of a third annular support element,

fig. 7 shows a third hydraulic connection in the region of the receiving opening of the fuel distributor line with a support ring according to the invention arranged on the fuel injection valve.

Detailed Description

For understanding the invention, a known embodiment of a fuel injection device is described in more detail below with reference to fig. 1. Fig. 1 shows a valve in the form of an injection valve 1 of a fuel injection system for a mixture-compressing, spark-ignition internal combustion engine in a side view as an exemplary embodiment. The fuel injection valve 1 is part of a fuel injection apparatus. The fuel injection valve 1 is embodied in the form of a direct injection valve for injecting fuel directly into a combustion chamber 16 of an internal combustion engine, which is fitted with a downstream end into a receiving bore 20 of a cylinder head 9. The sealing ring 2, which is composed in particular of PTFE or PTFE with filler material, ensures an optimal sealing of the fuel injection valve 1 with respect to the wall of the receiving bore 20 of the cylinder head 9.

An intermediate element 24, which serves, for example, as a damping element or decoupling element, is inserted between a shoulder 21 (not shown) of the valve housing 22 or a lower end side 21 (fig. 1) of the support element 19 and a shoulder 23 of the receiving bore 20, which extends, for example, at right angles to the longitudinal extent of the receiving bore 20. With such an intermediate element 24, manufacturing and assembly tolerances are also compensated for, and a support free of transverse forces is ensured even in the case of a slightly inclined position of the fuel injection valve 1.

The fuel injection valve 1 has, at its inflow end 3, a plug connection to a fuel distributor line (fuel rail) 4, which is sealed by a sealing ring 5 between an attachment socket (rail cup) 6, shown in cross section, of the fuel distributor line 4 and an inflow socket 7 of the fuel injection valve 1. The fuel injection valve 1 is inserted into a receiving opening 12 of the attachment stub 6 of the fuel distributor line 4. The attachment stub 6 projects from the actual fuel distributor line 4, for example, in one piece, and has a flow opening 15 of smaller diameter upstream of the receiving opening 12, through which flow to the fuel injection valve 1 is achieved. The fuel injection valve 1 has an electrical plug 8 for electrical contacting for actuating the fuel injection valve 1.

The electrical attachment plug 8 is connected via corresponding electrical connections to an actuator, not shown, by means of which the actuation of the actuator enables a reciprocating movement of the valve needle, as a result of which an actuation of the valve closing body can be effected, which valve closing body together with the valve seat surface forms a sealing seat. These last-mentioned components are not explicitly shown and can have any sufficiently known design. The actuator can be operated electromagnetically, piezoelectrically or magnetostrictively, for example.

In order to keep the fuel injection valve 1 and the fuel distributor line 4 largely spaced apart from one another without radial forces and to press the fuel injection valve 1 securely in the receiving bore 20 of the cylinder head 9, a pressing device 10 is provided between the fuel injection valve 1 and the attachment stub 6. The holding-down device 10 is embodied as an arcuate component, for example as a punch-bent part. The hold-down device 10 has a partially annular base element 11 from which a hold-down bow 13 extends in a curved manner, which in the installed state rests against a downstream end face 14 of the attachment socket 6 on the fuel distributor line 4.

Fig. 2 shows a known hydraulic connection in the region of the receiving opening 12 of the fuel distributor line 4. The sealing ring 5, which in the case of a so-called long valve with a particularly large axial extension is an additional attachment on the actual inflow socket 7, is clamped between the inner wall of the receiving opening 12 and the metallic inflow socket 7. Furthermore, a support ring 25 is provided below the sealing ring 5, which support ring bears, for example, against a conically running shoulder 26 of the metallic inflow socket 7 or of its attachment. In the metallic inflow socket 7 of the fuel injection valve 1 shown in fig. 2, namely, a conically extending section is provided which is surrounded in part by the sealing ring 5 and by a support ring 25 having an inner opening which likewise extends conically. Since the radial forces are also distributed as axial force components on the conically extending wall of the inflow socket 7, there is the risk of the sealing ring 5 slipping off on one side upwards away from the conical section if the axial force of the support ring 25 is greater than the thrust force of the sealing ring 5. This slipping-off may be accompanied by a reduction in the pressure of the sealing ring 5. In this embodiment of the fuel injection valve 1, the latter therefore has a radial support disk 30 in the region of the end flange 29 for the purpose of being secured against dropping at its inflow end 3. The radial support disk 30 is in this case embodied as a thin, compact disk, which can be composed of plastic (for example PEEK, PPS, POM) or of metal (for example aluminum). The radial support disk 30 is fitted axially from above onto the fuel injection valve 1, for example by means of an auxiliary spindle. Alternatively, the radial support disc 30 can be fitted by means of expansion claws or similar tools. In this respect, the radial support disc 30 is also arranged in front of the sealing ring 5, seen in the flow direction.

Fig. 3 shows a region of the receiving opening 12 of the fuel distributor line 4 with the fuel injection valve 1 according to the invention arranged thereonThe inventive first hydraulic interface of the support ring 25. The fuel injection valve 1 has a plastic injection molding 18 which forms at least part of a valve housing 22 and which surrounds the metallic inlet stub 7 over a large part of its extension. The plastic injection overmold 18 extends in the axial extent up to the vicinity of the hydraulic interface with the fuel distributor line 4. The invention is distinguished in that the support ring 25, which grips the sealing ring 5 from below, is placed directly on the upper end side 28, facing the sealing ring 5, of the annular support element 32 fastened to the inflow socket 7. The support element 32 is a metal ring which is very compact in its radial and axial extent and which is fastened directly to the outer circumference of the inflow socket 7, for example by means of a weld seam 33 or by means of a plurality of attachment points distributed over the circumference of the inflow socket 7. The requirements for the weld 33 or attachment point are not as high as for a sealing weld. Instead of a material-locking connection method, it is also possible to press or plastically deform, for example, by crimping (crimten) or flanging

To fasten the annular support element 32.

In the present case, the upper end face 28 of the annular support element 32 is embodied in a conically obliquely extending manner. The same applies to the conically extending shoulder 26 of the metallic inflow socket 7. The upper end side 28 of the support element 32 and the conically extending shoulder 26 of the metallic inflow socket 7 merge smoothly into one another, for example, with the same slope, and thus form a uniform upper inclined lower end in a circumferential manner. The support ring 25 contacts only the upper end side 28 of the support element 32, while the sealing ring 5 rests on the conically extending shoulder 26 of the metallic inflow socket 7 and naturally on the upper side of the support ring 25. An axial distance remains between the upper end of the plastic injection molding 18 and the underside of the support element 32, through which axial distance the inflow socket 7 is exposed radially to the outside and which serves as a mounting groove 34, for example, for enabling the weld seam 33 to be placed. This embodiment has the advantage that, in particular in the case of long valves, the inflow socket 7 can be implemented with a relatively thin wall over its entire axial extension, while the support ring 25 is provided with the required radial component placement only by means of small and compact support elements 32. According to the invention, an additional metal extension of the inflow socket 7, as shown, for example, in fig. 2, can be dispensed with.

The annular support element 32 can be produced, for example, by turning, stamping or drawing and consists, for example, of stainless austenitic steel (e.g., 1.4310).

Fig. 4 shows a second hydraulic connection according to the invention with a support ring 25 according to the invention arranged on the fuel injection valve 1 in the region of the receiving opening 12 of the fuel distributor line 4. The support element 32 is distinguished in that the upper end side 28 of the support element 32 facing the sealing ring 5 extends flat at right angles to the longitudinal valve axis.

In this case, a circumferential support ring 25 arranged according to the invention is provided, which is slipped onto the inflow nipple 7 of the fuel injector 1 before the above-mentioned radial support disk 30 or other fastening means is optionally placed. The support ring 25 loaded by the sealing ring 5 is provided with a V-shaped, indentation-like, conical seat for the sealing ring 5 in cross section, which is responsible for enabling the sealing ring 5 to be slightly radially offset to the radial inside and the radial outside in the event of a pressure increase and thus avoiding radial play. The support ring 25 rests with its underside flat against the upper end face 28 of the support element 32, which extends at right angles, and is supported there accordingly.

The support ring 25 is distinguished by its V-shaped resting surface 35 for the sealing ring 5. The support ring 25 has a slightly greater radial extent in its upper region facing the sealing ring 5 with the V-shaped contact surface 35 than on the remaining axial extension of the support ring 25 up to its underside. In this way, the support ring 25 can already be introduced into the receiving space between the fuel injection valve 1 and the attachment stub 6 by means of a small radial pressure in this upper region of the support ring 25. Due to the fluid pressure, two force components act via the sealing ring 5 on both sides of the V-shaped bearing surface 35 of the support ring 25. These forces lead to a slight elastic deformation of the support ring 25, to be precise in the radially inner and radially outer thin-walled regions below the contact surface 35 in the upper region which is slightly larger in the radial direction. That is, when the fluid pressure increases, a radial deflection and pressing of the support ring 25 in the radial direction inward and outward also occurs additionally, so that radial play is always avoided.

Fig. 5A and 5B show the second annular support element 32 in a plan view and in cross section according to fig. 4. The support element 32 is, for example, a slotted annular body with such radial material extensions that the support ring 25 can be placed reliably and over a large area. The slit 36 enables a simplified assembly. The annular supporting element 32 is embodied as a stamped and bent part.

Fig. 6A and 6B show a third annular support element 32 in a plan view and in cross section. The support element 32 is again embodied as a stamped and bent part, but here is embodied in a very thin-walled manner, wherein a profile having a U-shaped or C-shaped cross section is selected for sufficient stability and rigidity.

Fig. 7 shows a third hydraulic connection according to the invention with a support ring 25 according to the invention arranged on the fuel injection valve 1 in the region of the receiving opening 12 of the fuel distributor line 4. This third hydraulic connection differs only slightly from the first hydraulic connection according to the invention shown in fig. 3. In this embodiment, the inflow socket 7 is distinguished by a reworking in which a step 37 is produced on the outer circumference of the inflow socket below the support element 32, from which step the inflow socket 7 has a smaller outer diameter over the axial length a up to its upstream end than the outer diameter downstream of the step 37 of the inflow socket 7. The reworking can be effected, for example, by turning. The outer diameter of the inflow socket 7 is reduced by, for example, 0.05mm to 0.1 mm. This has the advantage that the sealing of the plastic injection moulding 18 with respect to the inflow nipple 7 is even further improved. Furthermore, radial tolerance limits of the support element 32 are advantageously accompanied.

Advantageously, the support ring 25 is made of plastic, wherein for example a material PA66 with 30% glass fibers is suitable. The V-shaped bearing surface 35 of the support ring 25 does not have to taper off in the center, but can be slightly rounded in the center of the base, as shown in fig. 4. The angle between the two sides of the V-shaped bearing surface 35 of the support ring 25 is approximately 60 ° to 100 °. For example, the support ring 25 has two flanks of the V-shaped seating surface 35 which extend at different heights, wherein the radially inner flank has a height in the axial direction which is smaller than the height of the radially outer flank. This can be advantageous if the sealing ring 5 is introduced into a receiving groove 43 on the inflow socket 7 with a smaller diameter, which is slightly recessed with respect to the support ring 25.

Claims

1. Fuel injection valve (1) for a fuel injection system of an internal combustion engine, in particular for the direct injection of fuel into a combustion chamber of the internal combustion engine, having an actuator, by means of the actuation of which a reciprocating movement of a valve needle can be achieved, as a result of which an actuation of a valve closing body can be achieved, which forms a sealing seat together with a valve seat surface, having an inflow-side inflow socket (7) for the supply of fuel, wherein a sealing ring (5) surrounding the inflow socket is arranged on the inflow socket (7), and having a plastic injection coating (18) which forms at least part of a valve housing (22),

it is characterized in that the preparation method is characterized in that,

a support ring (25) engages under the sealing ring (5), which in turn rests directly on the upper end side (28) of an annular support element (32) fastened to the inflow socket (7) facing the sealing ring (5).

2. The fuel injection valve according to claim 1,

it is characterized in that the preparation method is characterized in that,

the upper end side (28) of the annular support element (32) is embodied in a conically obliquely extending manner.

3. The fuel injection valve according to claim 2,

it is characterized in that the preparation method is characterized in that,

the inflow socket (7) is made of metal and has a conically extending shoulder (26), wherein the upper end side (28) of the support element (32) and the conically extending shoulder (26) of the inflow socket (7) extend at the same inclination and form a circumferential, uniform upper bevel end.

4. The fuel injection valve according to claim 2 or 3,

it is characterized in that the preparation method is characterized in that,

the support ring (25) has a conical inner side directed towards the upper end side (28) of the support element (32).

5. The fuel injection valve according to claim 1,

it is characterized in that the preparation method is characterized in that,

the upper end side (28) of the annular support element (32) is embodied in such a way that it extends flat at right angles to the longitudinal valve axis, and the support ring (25) can be placed flat on the upper end side by means of its underside.

6. The fuel injection valve according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the support ring (25) has a contact surface (35) for the sealing ring (5) that faces the sealing ring (5) and is V-shaped in cross section.

7. The fuel injection valve according to claim 6,

it is characterized in that the preparation method is characterized in that,

the V-shaped contact surface (35) of the support ring (25) has two side surfaces, on which two force components act via the sealing ring (5) when a fluid pressure is applied.

8. The fuel injection valve according to claim 6 or 7,

it is characterized in that the preparation method is characterized in that,

the radially inner side of the V-shaped contact surface (35) of the support ring (25) is embodied lower in its axial extent than the radially outer side of the V-shaped contact surface (35) of the support ring (25).

9. The fuel injection valve according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the annular support element (32) is a metal component and can be produced by turning, stamping or drawing or embodied as a stamped and bent part.

10. The fuel injection valve according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the support element (32) is fastened directly to the outer circumference of the inflow socket (7).

11. The fuel injection valve according to claim 10,

it is characterized in that the preparation method is characterized in that,

an axial distance remains between the upper end of the plastic injection molding insert (18) and the underside of the support element (32), through which axial distance the inflow nipple (7) is exposed radially outward and which serves as a mounting groove (34).