EP1722096B1 - Fuel injector with a leakage connection - Google Patents

Description

The present invention relates to an injector with leakage connection for the injection of fuel into a combustion chamber of an internal combustion engine.

As a fuel supply system for internal combustion engines increasingly storage injection systems are used, which operate at very high injection pressures. In these accumulator injection systems, fuel is conveyed by means of a high-pressure pump into a fuel injector, from which fuel is injected into the combustion chamber of the internal combustion engine. Such a fuel injector has an injection valve which is hydraulically opened or closed by a control valve by means of an applied fuel pressure. The control valve is actuated by an actuator.

Due to the high pressures occurs in particular during the control process by the control valve, a strong fuel return from the fuel injector, which is returned via a leakage line in a fuel tank. Such as from the DE 199 40 387 C1 As is known, the leakage connection on the injector is formed by a stepped bore, into which a line with a connection nipple is introduced. In order to prevent the connection nipple from being pushed out of the leakage connection by the outflowing fuel, the connection nipple is secured to the fuel injector by means of a flexurally elastic securing element. However, this arrangement is relatively expensive and includes a variety of individual components.

Another attachment possibility of a leakage line with nipple to a leakage connection of the injector by means of a spring element is for example from EP 0 886 065 A1 known, which, however, also a variety of components has and requires a relatively large manufacturing and assembly costs.

It is therefore an object of the present invention to provide injector with a leakage connection, which is simple in construction and simple and inexpensive to produce and allows a secure seal between the leakage connection and a leakage return line.

This object is achieved by a leakage connection with the features of claim 1. The subclaims show advantageous embodiments of the invention.

The connection of the leakage return line to a leakage connection at the fuel injector can be achieved by integrally forming the leakage connection with an already existing component of the injector and thereby integrally forming a leakage nipple for connecting a leakage return line to the leakage connection. According to the invention, the leakage connection with the function of connecting a leakage return line is thus integrated with an already existing component of the injector with a corresponding component function. As a result, the number of components can be kept low. The complex securing of a leakage nipple of the leakage return line in the leakage connection which is necessary in the state of the art can be dispensed with. Thus, furthermore, the elaborate stepped bore in the leakage connection, which is necessary in the state of the art, can be dispensed with. Thus, significant reductions in manufacturing costs can be achieved, which brings great cost advantages, especially in the high volumes of fuel injectors.

The leakage connection is constructed such that two leakage nipples are integrally formed on the component of the injector with leakage connection. Thus, the injector component has two Leak connections on, so that leakage can be derived at different points on the injector. The two leakage nipples are arranged opposite each other by 180 °.

In order to enable a simple assembly and a flow as possible flow-off of the leakage, the connection nipple are preferably arranged at an angle of approximately 45 ° to an injector main axis.

In order to enable a simple connection between the injector component with leakage connection and the injector, a recess is formed at a transition point between an internal injector leakage line and the leakage connection. Particularly preferably, the recess is formed as a circumferential groove, which is covered by the injector component with integrated leakage connection. It should be noted that the circumferential groove can of course also be formed in the injector component with leakage connection, or that a recess is provided both on the injector component with leakage connection and on the adjacent injector component, which then results in the assembled state, a circumferential channel.

In order to achieve a secure sealing of the transition point between the Injektorbauteil with leakage connection and the injector, the transition point is sealed by means of at least one sealing ring. The sealing ring can be arranged either in the injector component with leakage connection or the other injector component.

In order to accommodate the largest possible amount of leakage in the fuel injector, the injector has a substantially vertically extending leakage collecting bore, which is connected via a transverse bore with the leakage connection.

The injector component with integrated leakage connection is a coupling element between the injector and an engine component, e.g. the cylinder head. The coupling element is a centering sleeve or a damping component. The centering sleeve thus serves on the one hand for centering the injector in a cylinder head of the internal combustion engine and has as a further function the connection function of the leakage return line. In addition to the damping function, the damping component then additionally has the connection function of the leakage return line.

The inner wall of the coupling element is designed as a sealing seat for an annular seal. As a result, a secure seal the transition point between the coupling element and the injector is achieved.

The leakage connections of different injectors are connected to one another such that a leakage return line connected or arranged in series is formed. For this purpose, at least one injector component having a leakage connection has to have a plurality of leakage connections, and one of these leakage connections is finally connected to the leakage return line in the fuel storage container. The injector components are each formed with two leakage connections, so that a series connection with short paths can be realized in a simple manner.

In order to enable the most cost-effective manufacturability of injector with integrated leakage connection, the component is made of plastic. Thus, the Injektorbauteil with integrated leakage connection can be easily made, for example by injection molding. It is noted, however, that the leak connector may also be made of metal.

In order to enable a quick and easy attachment of the leakage return line to the leakage nipple, this has an undercut. As a result, the leakage return line is sufficiently secured to the leakage nipple and there is a simple and quick assembly and disassembly of the leakage return line given.

A leakage port for an injector comprises an integrally formed leakage nipple for connecting fuel to connect a leakage return line and an integrally formed holding device for injecting fuel. The holding device allows a fixation of the leakage connection to another, already existing Injektorbauteil. As a result, the connection of the leakage connection is integrated into an existing component of the injector.

The integrally formed holding device of the leakage connection has two clamping arms, which enable a frictional and positive connection with the existing injector component.

The clamping arms have a fixing area and a mounting auxiliary area. The fixing area serves for fastening the leakage connection to the already existing injector component.

Preferably, the clamping arms are arranged laterally on a leakage drain of the leakage connection. At the same time, a connection point between the clamping arms and the leakage outlet also serves as a pivot point for the clamping arms. Thus, the connection point continues to serve to divide the clamping arms into the fixing area and the mounting auxiliary area.

Particularly advantageously, the leakage connection is T-shaped with two integrally formed leakage nipples. This enables a redundant discharge of the leakage or facilitates a series connection of multiple leakage ports of different injectors.

Preferably, the injector component, to which the leakage connection can be fixed, is a fuel supply connection. This allows a particularly compact design of the leakage connection according to the invention. Particularly preferably, the fixing region of the clamping arms is formed flattened perpendicular to the axial direction of the fuel supply nozzle, so that an attachment of the clamping arms to the flattened fixing region, for example by means of a nut can be done.

Thus, the leakage connection allows a small number of components, which significantly reduces the assembly costs. Furthermore, no complicated fastening devices for fastening the leakage connection are necessary. In a fixation of the leakage connection to a fuel supply nozzle, a particularly compact design with significant space advantages can continue to be realized.

Figur 1

eine schematische Schnittansicht eines Injektorbauteils mit integriertem Leckageanschluss,

Figur 2

eine schematische Seitenansicht eines Injektors für einen in Figur 1 gezeigten Leckageanschluss,

Figur 3

eine Detailansicht des Details X von Figur 2,

Figur 4

eine schematische, perspektivische Ansicht eines Injektorbauteils mit integriertem Leckageanschluss,

Figur 5

eine schematische, teilweise geschnittene Ansicht von montierten Injektorbauteilen mit integriertem Leckageanschluss gemäß Figur 4,

Figur 6

eine schematische, perspektivische Teilansicht eines Speichereinspritzsystems mit einem Leckageanschluss,

Figur 7

eine perspektivische Ansicht eines Leckageanschlusses gemäß einem Ausführungsbeispiel der vorliegenden Erfindung, und

Figur 8

eine perspektivische Ansicht des in Figur 7 gezeigten Leckageanschlusses im montierten Zustand.

The invention will be described by means of preferred embodiments in conjunction with the drawing. In the drawing is:

FIG. 1

a schematic sectional view of an injector component with integrated leakage connection,

FIG. 2

a schematic side view of an injector for a in FIG. 1 shown leakage connection,

FIG. 3

a detailed view of the detail X of FIG. 2 .

FIG. 4

a schematic, perspective view of an injector with integrated leakage connection,

FIG. 5

a schematic, partially sectioned view of assembled injector components with integrated leakage connection according to FIG. 4 .

FIG. 6

a schematic, perspective partial view of a storage injection system with a leakage connection,

FIG. 7

a perspective view of a leakage connection according to an embodiment of the present invention, and

FIG. 8

a perspective view of the in FIG. 7 shown leakage connection in the assembled state.

As in FIG. 1 1, the injector component 1 with integrated leakage connection comprises a centering sleeve 2 and a leakage connection 3 formed integrally thereon. The centering sleeve 2 serves to center the fuel injector 6 in a bore in a cylinder head 13 of an internal combustion engine.

As in FIG. 1 the leakage connection 3 comprises an integrally formed nipple 4. The leakage connection 3 is at an angle α of approximately 45 ° to an injector main axis XX educated. In the cylinder head 13, a corresponding recess 19 for receiving the leakage connection 3 is formed. The leakage port 3 includes the nipple 4 integrally formed thereon and an inner leakage hole 5. Further, an undercut 12 is provided to securely fix a leakage return pipe (not shown).

As in particular from the FIGS. 2 and 3 it can be seen, in the injector 6, a vertically extending leakage collecting bore 8 is formed, in which the fuel return amount of the injector and leaks due to gaps between the injector components converges. From the leakage collecting bore 8, a horizontal transverse bore 7 goes to the outside of the injector 6. How out FIG. 1 it can be seen, a circumferential groove 11 in the injector 6 is formed in the region of the transverse bore 7. At this circumferential groove 11, the injector component 1 is arranged to guide the leakage flow in the leakage return line. In order to obtain a seal between the Injektorbauteil 1 and the injector 6, above and below the circumferential groove 11 each have a sealing ring 9, 10 is arranged. The accumulated in the vertical leakage collection hole 8 leakage is thus guided via the horizontal transverse bore 7 and the circumferential groove 11 to the leakage port 3 and from there into the leakage return line.

Thus, the Injektorbauteil 1 comprises both the centering 2 and the integrally formed therewith leakage connection 3 with integrated nipple 4. According to the invention, therefore, the number of components can be kept low, while a secure connection can be obtained by providing the nipple 4 for attachment of a leakage return line. By providing the undercut 12, a leakage return line placed over the nipple 4 is securely fastened to the leakage connection 3. Thus, a quick assembly or disassembly can be achieved. If a particularly secure connection between the leakage return line and the leakage connection 3 is desired, in addition, a clamping member, such as a clamp, are attached to the outside of the leakage return line in the region of the undercut to clamp the leakage return line to the undercut 12.

The following is with reference to the FIGS. 4 to 6 an injector component 1 with integrated leakage connection 3 according to a second embodiment of the present invention described. The same or functionally identical parts are again denoted by the same reference numerals.

As in particular in the FIGS. 4 and 5 In the second exemplary embodiment, however, in the second exemplary embodiment, a first leakage connection 3 and a second leakage connection 14 are formed with an integrally formed nipple 15. In the second exemplary embodiment, the injector component 1 according to the second exemplary embodiment also comprises a centering sleeve 2. Thus, the Injektorbauteil 1 according to the second embodiment comprises two integrally formed leakage ports 3 and 14. The two leakage ports 3 and 14 are in this case arranged 180 ° opposite to each other. An inner wall 16 of the centering sleeve 2 is formed as a contact surface for two sealing rings, which seal a formed on the injector 6, circumferential groove 11.

Like from the Figures 5 and 6 it can be seen, the individual injectors 6 are each secured by means of clamping claws 18 on the cylinder head 13. The clamping claw 18 fixes the injector 6 in the cylinder head 13 with respect to axial displacements. The sleeves 2 are designed such that they can compensate for installation tolerances with respect to a fixation in the axial direction XX.

Due to the design of the Injektorbauteils 1 with two leakage ports 3 and 14, it is possible, in particular from the Figures 5 and 6 can be seen, a leakage return in one Form series connection. The resulting at the injector 6 leakage is discharged through the circumferential groove 11 to both the first leakage port 3 and the second leakage port 14. From the second leakage connection 14, the leakage is guided via a leakage return line 17 to a first leakage connection 3 'of a second injector 6'. From the second injector 6 'is a circumferential groove 11' ( FIG. 5 ) the leakage is further led to a second leakage connection 14 'of the second injector 6' and guided via the leakage line 17 'to a third injector 6''. From the third injector 6 '', the leakage in the same way via the leakage return line 17 '' to a fourth injector 6 '''out and guided by the second leakage port 14''' back to a fuel tank. Due to this design of the arrangement of a plurality of leakage ports of different injectors in series, a particularly compact design for the leakage return can be made possible. How out FIG. 6 it can be seen, the leakage can be discharged via the first leakage port 3 of the first injector 6 and the second leakage port 14 '''of the fourth injector 6'''. As a result, a redundant leakage return can be formed. There are very short cable paths between the individual injectors.

By combining two functions in one component, namely a connection function for a leakage line and a centering function for the injector, fewer components than in the prior art are needed. This reduces the assembly effort, and also the manufacturing cost can be reduced. Furthermore, in particular by arranging the leakage return lines in series, a particularly compact leakage device can be provided. This results in space advantages over the prior art.

Thus, the present invention relates to an injector with leakage port 3 for injecting fuel into a combustion chamber of an internal combustion engine. The leakage connection 3 is formed integrally with an injector component 1. Furthermore, a leakage nipple 4 for connecting a leakage return line 17 is integrally formed on the leakage connection 3.

The following is with reference to the FIGS. 7 and 8 a leakage port 23 according to an embodiment of the present invention is described.

In contrast to the previous examples, in the leakage connection according to this embodiment, a holding device consisting of a first clamp arm 28 and a second clamp arm 29 is integrally formed with the leakage port 23.

As in particular from FIG. 7 it can be seen, the leakage connection 23 is T-shaped. The leakage connection 23 comprises a leakage drain 26 which is fastened in the injector and opens into a branching line 27 which has an integrally formed connection nipple 24, 25 at each of its two ends. Thus, the leakage port 23 has a substantially T-shape.

How to continue FIG. 7 it can be seen, the two clamping arms 28, 29 are integrally formed with the leakage connection 23 at the periphery of the branch line 27 directed to the injector. In this case, the first clamping arm 28 has a fixing region 30 and an auxiliary mounting region 31. The second clamping arm 29 likewise has a fixing region 32 and an auxiliary mounting region 33. At the junction between the clamping arms 28, 29 and the leakage drain 26, the clamping arms 28, 29 are pivotally mounted. This can be realized, for example, such that the leakage connection 23 completely made of a plastic by injection molding. The mounting auxiliary areas 31, 33 are used during assembly in such a way that they are moved against each other by compression in the direction of the arrows A and B, respectively. As a result, the fixing regions 30 and 32 of the clamping arms 28 and 29 spread apart, so that a simple mounting of the leakage connection 23 is made possible. The spreading of the fixing regions 30 and 32 takes place by means of a lever principle, so that only small assembly forces are necessary.

Due to the elasticity of the clamping arms 28 and 29 take this after removal of the mounting forces on the auxiliary mounting portions 31 and 33 back to their original shape.

In FIG. 8 the assembled state of the leakage connection 23 is shown. As in FIG. 8 shown, the clamping arms 28, 29 engage around a high pressure supply nozzle 21. The clamping arms 28, 29 are fixed by means of a nut 22 on the supply nozzle 21. For easier fixation, the clamping arms 28, 29 are formed flattened perpendicular to the axial direction of the supply nozzle 21 at its fixing region 30, 32. As a result, a secure attachment of the leakage connection to the supply nozzle 21 can be made possible. By attachment to the supply nozzle 21 is still still a certain extent existing Drehausrichtung and fixing the position of the leakage port 23 possible. Thus, the clamping arms 28, 29 engage in the assembled state in a threaded groove formed on the feed port 21. Accordingly, a non-positive and positive connection between the leakage connection 23 and the supply nozzle 21 can be produced. Furthermore, the leakage connection 23 according to the invention can also be dismantled again without destruction from the supply pipe 21, for example, a repair or the like. to enable the injector 20.

The preceding description is for illustrative purposes only and not for the purpose of limiting the invention. Various modifications may be made within the scope of the invention without departing from the scope of the invention as defined in the claims.

Claims (4)

1. Injector with a leakage connection (23) for injecting fuel into a combustion chamber of an internal combustion engine, whereby the leakage connection (23) includes an integrated leakage nipple (24, 25) for attaching a leakage return line (17) and an integrated retaining device (28, 29) in order to allow the leakage connection (23) to be fixed to another injector component (21), with the retaining device including two clamping arms (28, 29) for a force-fit and/or form-fit connection to the injector component (21), and with the clamping arms (28, 29) including a fixing area (30, 32) and an installation assistance area (31, 33), characterised in that the clamping arms (28, 29) are arranged laterally on a leakage drain (26) of the leakage connection (23), whereby the connection point between the clamping arms (28, 29) and the leakage drain (26) is also configured at the same time as a swivel point for the clamping arms (28, 29).
2. Injector with a leakage connection according to claim 1, characterised in that the leakage connection (23) is constructed in a T-shape with two integrated leakage nipples (24, 25)
3. Injector with a leakage connection according to one of claims 1 or 2, characterised in that the injector component to which the leakage connection (23) can be fixed is a fuel supply branch (21).
4. Injector with a leakage connection according to Claim 3, characterised in that the fixing areas (30, 32) are constructed in flattened form, perpendicular to the axial direction of the fuel supply branch (21).

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