EP3244057A1 - Assembly for a fuel injection system with a fuel injection valve and a decoupling element - Google Patents

Abstract

A decoupling element (3) serves for decoupling a fuel injection valve (2) from a cylinder head. The decoupling element (3) has a main body (6), which serves in the mounted state for enclosing a housing (5) of the fuel injection valve (2). In this case, a cylinder-side support region (7) is designed on the base body (6), which serves for supporting on the cylinder head (4). Further, a valve-side support region (8) is designed on the base body (6), which serves to support the fuel injection valve (2). When supporting the fuel injection valve (2) between the valve-side support area (8) and the cylinder-side support area (7), the base body (6) is pressurized. In this case, only the cylinder-side support region (7) of the base body (6) is configured in the form of a closed ring, while the base body (6) has segments (15-18) distributed over a circumference which pass through the closed ring (20) of the cylinder-side support region (7) are interconnected. The decoupling element (3) in this case enables the reduction of noise transmission from the fuel injection valve (2) to the cylinder head (4). Furthermore, an arrangement (1) with such a decoupling element (3) and a fuel injection valve (2) is described.

Description

State of the art

The invention relates to a decoupling element, which serves for decoupling a fuel injection valve from a cylinder head, and an arrangement with a fuel injection valve and such a decoupling element. Specifically, the invention relates to the field of fuel injection systems of internal combustion engines, wherein high pressure fuel is injected through fuel injectors into associated combustion chambers of the internal combustion engine.

From the DE 103 38 715 A1 a compensation element for a fuel injection valve is known. The compensating element serves to support a fuel injection valve in a cylinder head of an internal combustion engine. The compensation element is annular and arranged between a valve housing of the fuel injection valve and a wall of a receiving bore of the cylinder head. The compensation element has legs, which are supported on the fuel injection valve and the cylinder head. Here, a first leg bears against a shoulder of the cylinder head. A second leg abuts against a shoulder of the valve housing. On the compensating element undercuts and openings can be provided. In this case, the compensating element may have segments that are punched out of the compensating element and bent radially inward. In this way, the compensation element ensures both a compensation of manufacturing tolerances of the individual components as well as tolerances, which are due to the heating of the fuel injection valve during operation, and thus prevents tilting and misalignments.

The from the DE 103 38 715 A1 known configuration of the compensation element for a fuel injection valve has the disadvantage that at a correspondingly large load circumferentially stresses in the material occur, which can lead to cracks on the periphery and finally to the failure of the compensation element.

From the DE 10 2008 054 591 A1 a decoupling element for a fuel injection device is known. The decoupling element realizes a low-noise construction. The spring stiffness of the decoupling element is chosen so low and the decoupling element is placed such that the Entkoppelresonanz in the frequency range below 2.5 kHz. In one possible embodiment, a possible misalignment of a fuel injection valve is absorbed by a local weakening of an inner bearing region of the decoupling element. This local weakening of the radially inner bearing area is achieved by radially extending slots, which extend from the inner diameter of the decoupling element, for example, to the inner radius. Typically, such slots or other stiffness reducing apertures may be provided here in a number from three to twenty.

That from the DE 10 2008 054 591 A1 known decoupling element has the disadvantage that it is constructed according to a plate spring and is loaded in the mounted state to train. Thus, over the life of the problem arises to ensure sufficient component strength and at the same time the desired noise reduction.

Disclosure of the invention

The decoupling element according to the invention with the features of claim 1 and the arrangement according to the invention with the features of claim 10 have the advantage that an improved vibration damping over the life is guaranteed. Specifically, there is the advantage that sufficient noise attenuation is ensured even after a long service life and premature component failure is avoided.

With the proposed decoupling element, the noise transmission of the fuel injection valve to the cylinder head can be reduced in a simple manner, with the least possible space and with low additional costs. In this case, a predetermined target rigidity, for example of less than 50 kN / mm can be maintained. The associated operational stability, which is required especially at high system pressures, such as in a gasoline direct injection, can be ensured. Here, a vibration isolation, decoupling and decoupling of structure-borne noise can be ensured.

As a background of the invention has been found that rotationally symmetrical configurations, as in disc springs, in a decoupling element for high system pressures and thus large axial loads in conjunction with the predetermined very small space does not give the desired result. This is because such embodiments by the forces acting and the resulting deformations form large hoop stresses that lead to the periphery to cracking and eventually failure of the component. One conceivable solution is to counteract these problems by increasing the wall thickness. Due to the massive design of these elements for stress reduction but then the required decoupling stiffness can no longer be guaranteed.

According to the invention, the problem of the circumferential stresses can be limited by a special segmentation, which means breaking the rotational symmetry. The decoupling stiffness then results from the sum of the stiffnesses of the individual segments distributed over the circumference. This corresponds to a parallel connection of bending springs. The segments acting as individual bending elements are held together only by a comparatively small, circumferential, closed ring of the cylinder-side support region of the basic body. Thus, for a better elasticity of the segments is achieved because they are designed comparatively large and thus can be designed for a given target stiffness with comparatively thick material thickness. On the other hand, the mechanical circumferential stresses concentrate on the cylinder-side contact area of the main body, which contributes nothing to the spring behavior and can thus be designed with respect to the required peripheral forces.

The advantage of this special segmentation in the individual segments serving as bending elements is therefore also that, while maintaining the required stiffness values, significantly lower loads occur in the component and thus the strength requirements for the material are lower.

A further advantage is that in the shape of the segments (bending elements), the function of the required for lateral force compensation tolerance compensation element can be integrated in a simple manner. By a spherical or similar design of the segments, the fuel injection valve on the decoupling element as a ball joint tilt and thereby acting lateral forces and tolerance offsets between a center line of a mounting hole on the cylinder head and a center line of a rail cup can be compensated.

Thus, the embodiment according to the invention, in which only the cylinder-side support region of the base body is configured at least partially in the form of a closed ring, has significant advantages. This embodiment is to be understood in such a way that the main body is in any case segmented outside the cylinder-side support area into the segments distributed over the circumference. However, this also includes the possibility that the segments distributed over the circumference also partially extend into the cylinder-side support region of the main body. Then the cylinder-side support region of the base body is only partially configured in the form of a closed ring.

Only if the cylinder-side support region of the main body is designed entirely in the form of a closed ring, then the distributed over the circumference segments of the body do not extend into the cylinder-side support area.

It is advantageous that the base body is subjected to pressure during the support of the fuel injection valve between the valve-side support region and the cylinder-side support region. As a result, the segments distributed over the circumference can advantageously act as bending segments. In this case, comparatively large bending movements are possible with respect to a given maximum stress of the material. This allows, inter alia, an advantageous tolerance compensation with respect to the positioning of the fuel injection valve.

It is also advantageous that the closed ring of the cylinder-side bearing region between the circumferentially distributed segments bulges, which extend radially outward. Here, it is also advantageous that the base body has recesses which are provided between the segments of the base body and that the recesses of the base body partially extend into the cylinder-side support region of the base body, so that the cylinder-side support region of the base body only partially in the form of a closed ring is designed. In this embodiment, the distributed over the circumference segments of the body thus also extend slightly into the support area. This further facilitates bending of the segments. The occurring component voltages in the circumferential direction can be concentrated in an advantageous manner to the closed ring. The bulges provided between the circumferentially distributed segments, which in turn are distributed around the circumference, ensure a sufficiently large material cross-section in the region of the segments in order to absorb the forces acting in the circumferential direction. At the same time, the bulges do not influence the bending behavior of the segments. However, the bulges on the cylinder head can be increased by the bulges. Thus, the bulges allow for improved design with other advantages. It is also advantageous that the bulges of the closed ring, which partially bridge in the cylinder-side bearing region of the body extending recesses. In this embodiment, the bulges also extend somewhat into the areas of the cylinder-side support region, which adjoin the recesses in the circumferential direction in each case on both sides. Thus, an advantageous introduction of force is achieved in the areas adjacent to the recesses and thus an advantageous adhesion over the circumference.

It is also advantageous that the closed ring of the cylinder-side support region is designed as an at least essentially flat cylinder-side support region for the cylinder head. This results in an advantageous support surface and a reliable positioning on the cylinder head.

It is also advantageous that at least on a segment of the valve-side support region, a securing element is configured, which cooperates in the assembled state with the housing of the fuel injection valve. In particular, a plurality of securing elements may be provided, which are each biased in the radial direction against the housing of the fuel injection valve to form a captive. As a result, an advantageous assembly of the arrangement of the fuel injection valve and the decoupling element attached thereto is possible.

Furthermore, it is advantageous that the closed ring of the cylinder-side bearing region is at least indirectly connected to a snap ring, which cooperates in the mounted state with the housing of the fuel injection valve. This also represents a possibility for securing the decoupling element to the fuel injection valve, for example during pre-assembly. As a result, the arrangement of the fuel injection valve and the decoupling element can be mounted in a simple manner on the cylinder head.

Brief description of the drawings

• Fig. 1 eine Anordnung mit einem Brennstoffeinspritzventil und einem Entkoppelelement sowie einen Zylinderkopf in einer auszugsweisen, schematischen und räumlichen Darstellung entsprechend einem ersten Ausführungsbeispiel der Erfindung;
• Fig. 2 die in der Fig. 1 dargestellte Anordnung und den Zylinderkopf entsprechend einem zweiten Ausführungsbeispiel der Erfindung;
• Fig. 3 die in Fig. 1 dargestellte Anordnung und den Zylinderkopf entsprechend einem dritten Ausführungsbeispiel der Erfindung;
• Fig. 4 das Entkoppelelement der in Fig. 1 dargestellten Anordnung entsprechend dem ersten Ausführungsbeispiel der Erfindung in einer auszugsweisen, schematischen und räumlichen Darstellung zur Veranschaulichung der Funktionsweise einer möglichen Ausgestaltung der Erfindung;
• Fig. 5 eine Anordnung mit einem Brennstoffeinspritzventil und einem Entkoppelelement sowie einen Zylinderkopf in einer auszugsweisen, schematischen Schnittdarstellung entsprechend einem vierten Ausführungsbeispiel der Erfindung;
• Fig. 6 die in Fig. 5 dargestellte Anordnung und den Zylinderkopf entsprechend einem fünften Ausführungsbeispiel der Erfindung und
• Fig. 7 die in Fig. 5 dargestellte Anordnung und den Zylinderkopf entsprechend einem sechsten Ausführungsbeispiel der Erfindung.

Preferred embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with identical reference numerals. It shows:

• Fig. 1 an arrangement with a fuel injection valve and a decoupling element and a cylinder head in an excerpt, schematic and spatial representation according to a first embodiment of the invention;
• Fig. 2 the in the Fig. 1 illustrated arrangement and the cylinder head according to a second embodiment of the invention;
• Fig. 3 in the Fig. 1 illustrated arrangement and the cylinder head according to a third embodiment of the invention;
• Fig. 4 the decoupling of the in Fig. 1 illustrated arrangement according to the first embodiment of the invention in a partial, schematic and spatial representation to illustrate the operation of a possible embodiment of the invention;
• Fig. 5 an arrangement with a fuel injection valve and a decoupling element and a cylinder head in a partial, schematic sectional view according to a fourth embodiment of the invention;
• Fig. 6 in the Fig. 5 illustrated arrangement and the cylinder head according to a fifth embodiment of the invention and
• Fig. 7 in the Fig. 5 illustrated arrangement and the cylinder head according to a sixth embodiment of the invention.

Embodiments of the invention

Fig. 1 shows an arrangement 1 with a fuel injection valve 2 and a decoupling element 3 and a cylinder head 4 in an excerpt, schematic and spatial representation according to a first embodiment. The arrangement 1 is used for a fuel injection system of internal combustion engines. In this case, the arrangement 1 is particularly suitable for fuel injection systems for the direct injection of fuel into combustion chambers of the internal combustion engine. Specifically, the internal combustion engine may be configured as a mixture-compression, spark-ignited internal combustion engine, whereby gasoline or other fuels suitable for such internal combustion engines as well as suitable mixtures of such fuels can be injected.

The decoupling element 3 is particularly suitable for such applications.

By the arrangement 1 and the decoupling element 3, a reduction of the noise transmission from the fuel injection valve 2 to the cylinder head 4 is possible.

For example, the fuel injection valve 2 can be configured as a high-pressure electromagnetic injection valve 2, which is used in direct injection gasoline engines. Without a decoupler there is the problem that the fuel injector 2 makes a conspicuous and disturbing contribution to the overall noise of the engine. A recordable as a valve trough noise can be caused for example by the rapid opening and closing of the fuel injection valve 2, when a valve needle is moved with high dynamics in the respective end stops. The impact of the valve needle on the end stops leads to short-term, very high contact forces, which can be transmitted via a housing 5 of the fuel injection valve 2 in large parts on the cylinder head 4 as structure-borne noise and vibrations. This then leads to the cylinder head 4 to a strong noise, but by the decoupling element 3, which is located between the cylinder head 4 and the fuel injection valve 2, is significantly reduced.

However, in addition to the reduction of the noise development, the decoupling element 3 also has the requirement that it exhibits the required decoupling rigidity and required strength with respect to a given small installation space, in particular at high system pressures over the service life. This is achieved by the embodiment of the inventive decoupling element 3 described below with reference to the exemplary embodiments.

The decoupling element 3 has a main body 6 with a cylinder-side support region 7 and a valve-side support region 8. The cylinder-side support region 7 serves for supporting on an upper side 9 of the cylinder head 4. The valve-side support region 8 serves to support the fuel injection valve 2. In the mounted state, which is in the Fig. 1 is shown, the decoupling element 3 surrounds the housing 5 of the fuel injection valve 2 circumferentially. The top 9 of the cylinder head 4 is configured in this embodiment as a flat top 9.

The base body 6 of the decoupling element 3 is subjected to pressure during the support of the fuel injection valve 2 between the valve-side support region 8 and the cylinder-side support region 7. The base body 6 in this case distributed over the handling segments 15, 16, 17, 18, which are bent elastically during the application. Due to the segmentation of the valve-side support region 8, an optimal elasticity over the service life is ensured with respect to the predetermined material thickness. Circumferentially acting stresses are considerably reduced by the segmentation in the valve-side support region 8. Furthermore, the cylinder-side support region 7 of the base body 6 is at least partially in the form of a closed ring 20 configured. In this case, only the cylinder-side support region 7 of the main body 6 is configured at least partially in the form of the closed ring 20. In this embodiment, the cylinder-side support region 7 of the base body 6 is configured only partially in the form of a closed ring 20. For recesses 21, 22, 23 are provided between the segments 15 to 18, which also extend somewhat into the cylinder-side support region 7. This leaves, for example, at the recess 22 a web 25 of the closed ring 20, in which the cylinder-side support portion 7 viewed in the circumferential direction a reduced radial extent of a flat support surface 26 (FIG. Fig. 5 ) having.

The closed ring 20 of the cylinder-side support region 7 is designed in this embodiment as a flat cylinder-side support region 7 with a flat contact surface 26 for the cylinder head 4. Thus, a reliable positioning of the cylinder head 4 is possible. This also improves the vibration damping with an optionally simultaneously required tolerance compensation for the fuel injection valve. 2

The recesses 21, 22, 23 extending in the cylinder-side support region 7 are preferably maximally pronounced, so that the remaining ring strength at the web 25 is reduced to a possible minimum.

Fig. 2 shows the in Fig. 1 illustrated arrangement 1 and the cylinder head 4 according to a second embodiment. In this embodiment, an outer edge 27 of the closed ring 20 as viewed from the top 9 of the cylinder head 4 is bent away upward. With regard to the particular application, this allows a stability of the closed ring 20, in particular at the web 25, to be improved, especially in tight spaces.

Fig. 3 shows the in Fig. 1 illustrated arrangement 1 and the cylinder head 4 according to a third embodiment. In this embodiment, the closed ring 20 of the cylinder-side support region 7 between the circumferentially distributed segments 15 to 18 bulges 28, wherein for simplicity of illustration, only the bulge 28 is characterized. The bulge 28 extends radially outward. Here, the support surface 26 of the cylinder-side support region 7 is increased by the bulge 28 in this embodiment. In this case, the bulge 28 bridges the recess 22 which partially extends into the cylinder-side support region 7. This increases the cross-sectional area, which is significant for the absorption of the circumferential tensile forces, in particular in the region of the web 25.

This reduces the corresponding tensile stresses. For this purpose, the bulge 28 also extends into regions (zones) 29, 30 of the cylinder-side support region 7, which adjoin the recess 22 in the circumferential direction. The zones 29, 30 thus enable an advantageous frictional connection in the closed ring 20.

Fig. 4 shows the decoupling element 3 of in Fig. 1 illustrated arrangement 1 according to the first embodiment of the invention in a partial, schematic and spatial representation to illustrate the operation of a possible embodiment of the invention. The illustrated section may be, for example, a quarter of a possible embodiment. The upwardly bent segments 16, 17 are designed in the form of bent tabs which provide the fuel injection valve 2 at the drawn for illustrative line 31 a support or support. About this line (support line) 31, the load is transmitted to the decoupling element 3 due to the low pressure and the pressure forces at the fuel injection valve. The segments 16 to 18 bend through the load. The total stiffness of the decoupling then results from the sum of the individual bending stiffnesses. This corresponds to a parallel connection of individual bending springs. Due to the spherical shape of serving as bending elements segments 15 to 18 and the corresponding mating contour on the housing 5 of the fuel injection valve 2 in the decoupling and the function of a tolerance compensation for the compensation of lateral forces and / or a tolerance-related offset is integrated.

Depending on the application, the segments 15 to 18 in a suitable form, number and thickness can be designed by optimizing the shape so that the desired stiffness is achieved with the required strength.

Fig. 5 shows an arrangement 1 with a fuel injection valve and a decoupling element 3 and a cylinder head 4 in an excerpt, schematic sectional view according to a fourth embodiment. Here, a segment 18 of the base body 6 is shown in section for illustration. On the segment 18 and other segments, not shown, the valve-side support portion 8 is configured, wherein the housing 5 rests, for example, on the line 31 of the segments 18, as also with reference to FIG Fig. 4 is described accordingly.

Further, a fuse element 32 is configured on the segment 18 in this embodiment. In this case, further securing elements configured correspondingly to the securing element 32 are preferably configured on further segments, not shown. The fuse element 32 acts in the illustrated assembled state with the housing 5 together. In this case, the securing element 32 can be expanded during application to the housing 5 in the radial direction to the outside. In particular, a clawing into the housing 5, in particular a magnet pot of the housing 5, can be achieved by a special shaping of the securing element 32. As a result, a captive is formed.

Fig. 6 shows the in Fig. 5 illustrated arrangement 1 and the cylinder head 4 according to a fifth embodiment. In this embodiment, the segment 18 is configured as an inwardly open segment 18. This embodiment has the additional advantage that an end stop can be realized in order to limit the maximum deformation of the segment 18. In this case, a spacer element 33, which faces the cylinder-side support region of the main body 6, is configured on the segment 18 of the valve-side support region 8. When the valve-side support region 8 is acted upon against the cylinder-side support region 7, the spacer 33 strikes against the cylinder-side support region 7 after a certain movement path. Thus, the spacer element 33 then cooperates with the cylinder-side support area to limit the possible range of motion.

Further, in this embodiment, a snap ring 34 is provided which cooperates with the housing 5. The closed ring 20 of the cylinder-side support region 7 is at least indirectly connected to the snap ring 34, so that the decoupling element 3 is reliably fixed to the housing 2. This facilitates, in particular, an assembly of the fuel injection valve 2 in the cylinder head 4, since the decoupling element 3 can already be preassembled on the fuel injection valve 2.

Depending on the application, a decoupling element 3, which is open to the outside, can thus be used, for example, with reference to FIG Fig. 1 to 4 is described as well as an inwardly open decoupling element 3, as it is based on the Fig. 6 and the Fig. 7 is described, realized.

Fig. 7 shows the in Fig. 5 illustrated arrangement 1 and the cylinder head 4 according to a sixth embodiment. In this exemplary embodiment, the housing 5 of the fuel injection valve 2 has an undercut cone 35, on which the fuel injection valve 2 is supported on the valve-side support region 8 of the decoupling element 3. Here, the housing 5 rests with its undercut cone 35 on the line 31 of the valve-side support region 8. In this embodiment, the embodiment of the decoupling element 3 is simplified.

Thus, an arrangement 1 can be realized, which is used for a fuel injection system of internal combustion engines. Here, the fuel injection valve 2 can be supported in the assembled state via the decoupling element 3 on the cylinder head 4 of the internal combustion engine.

The invention is not limited to the described embodiments.

Claims (4)

Decoupling element (3), which serves for decoupling a fuel injection valve (2) from a cylinder head (4), with a base body (6) which serves in the assembled state for enclosing a housing (5) of the fuel injection valve (2), wherein on the base body (6) a cylinder-side support region (7), which serves for supporting on the cylinder head (4), and a valve-side support region (8), which serves to support the fuel injection valve (2) are configured, wherein only the cylinder-side support region (7) the base body (6) is configured at least partially in the form of a closed ring (20) and the base body (6) has segments (15-18) distributed over a circumference, which engage with each other through the closed ring (20) of the cylinder-side support area (7) are connected,
characterized,
in that at least on one segment (18) of the valve-side support region (8) a securing element (32) is designed which, in the assembled state, cooperates with the housing (5) of the fuel injection valve (2) to form a captive securing device. Decoupling element (3), which serves for decoupling a fuel injection valve (2) from a cylinder head (4), with a base body (6) which serves in the assembled state for enclosing a housing (5) of the fuel injection valve (2), wherein on the base body (6) a cylinder-side support region (7), which serves for supporting on the cylinder head (4), and a valve-side support region (8), which serves to support the fuel injection valve (2) are configured, wherein only the cylinder-side support region (7) the base body (6) is configured at least partially in the form of a closed ring (20) and the base body (6) has segments (15-18) distributed over a circumference, which engage with each other through the closed ring (20) of the cylinder-side support area (7) are connected,
characterized,
in that the closed ring (20) of the cylinder-side support region (7) is at least indirectly connected to a snap ring (34) which, in the assembled state, interacts with the housing (5) of the fuel injection valve (2). Decoupling element according to claim 1 or 2,
characterized,
in that on at least one segment (18) of the valve-side support region (8) a spacing element (33) is designed which, when the valve-side support region (8) is acted upon, acts against the cylinder-side support region (7) with the cylinder-side support region (7) for limiting a movement region works together. Arrangement (1), which is used for a fuel injection system of internal combustion engines, with at least one fuel injection valve (2) and a decoupling element (3), wherein the decoupling element (3), which serves for decoupling the fuel injection valve (2) from a cylinder head (4), with a base body (6), which in the installed state serves for enclosing a housing (5) of the fuel injection valve (2) is executed, wherein on the base body (6) has a cylinder-side support area (7) for supporting on the cylinder head (4 ), and a valve-side support region (8), which serves to support the fuel injection valve (2), are configured, wherein only the cylinder-side support region (7) of the base body (6) is at least partially designed in the form of a closed ring (20) and the base body (6) has segments (15-18) distributed over a circumference, which join together through the closed ring (20) of the cylinder-side support region (7) are connected
wherein the fuel injection valve (2) in the mounted state via the decoupling element (3) on a cylinder head (4) of the internal combustion engine can be supported,
characterized,
in that the housing (5) of the fuel injection valve (2) has an undercut cone (35) on which the fuel injection valve (2) is supported on the valve-side support region (8).

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