EP2705245B1 - Fuel distributor - Google Patents

Description

State of the art

The invention relates to a fuel distributor, which is used in particular for fuel injection systems of mixture-compression, spark-ignited internal combustion engines, and a system with a fuel injection valve. Specifically, the invention relates to the field of fuel injection systems designed as medium-pressure systems.

In automotive fuel injection systems, it is conceivable to use a fuel rail designed for high pressure steel or aluminum applications. As a result, a compressive strength for pressures of, for example, 20 MPa (200 bar) can be achieved. Fuel rail manifolds may also be used for low pressure applications at 0.5 MPa (5 bar). However, the scope of such fuel rail for low pressure applications is limited to this low pressure range.

For mounting a fuel injection valve, it is conceivable that a hold-down spring is used, which sits between the fuel rail and the fuel injection valve. Here, for example, by a holding force of 500 N, the fuel injection valve can be held down in a cylinder head of an internal combustion engine. Thereby, the fuel injection valve is securely positioned on the cylinder head, wherein neither by the combustion pressure of a combustion chamber nor by vibration accelerations removal of the fuel injection valve may occur from the desired position. In order to enable the support of the hold-down spring on the fuel rail with respect to the desired biasing force of, for example, 500 N, an embodiment of the metal fuel distributor strip is required.

Disclosure of the invention

From the US 2009/0178650 A1 A fuel distributor is already known which is suitable for fuel injection systems of mixture-compressing, spark-ignited internal combustion engines. The fuel distributor has a distributor body, in which a fuel chamber is configured, and at least one support element, wherein on the distributor body at least one cup is provided, on which the support element is arranged, and wherein the support element at least partially forms a support surface at one end of the cup. The support member is carried out in various embodiments in each case as a solid, compact, annular component, which protects mainly the lower end of the cup and is supported there.

The fuel distributor according to the invention with the features of claim 1 has the advantage that the use of a hold-down spring or the like with reduced requirements for at least one material that is used to design the fuel distributor, is possible. In particular, it is possible that cost-effective, but only with a surface pressure acted upon materials are used.
The measures listed in the dependent claims advantageous developments of the fuel distributor specified in claim 1. It is advantageous that the distributor body and the cup are formed from a plastic. In this case, it is also advantageous that the distributor body comprises the cup, so that the cup is an integral part of the distributor body. For example, the distributor body can be designed with several cups as an injection molded part. Due to the design of plastic cost-effective production is possible. However, there is the problem with plastic that it flows away at high surface pressures and the required tolerances can no longer be met. To avoid this, a support surface is formed by the arranged on the cup support member, which allows a support of a hold-down spring or the like. The acting on the plastic surface pressure is thereby significantly reduced, so that a flow away of the plastic is avoided and the required tolerances can be met. The support member is configured as an annular support member, wherein the support member is connected to the end of the cup. Specifically, an annular configuration of the support member allows a uniform force distribution of the hold-down spring on the end of the cup and at the same time a good connection of the support member with the end of the cup.

It is advantageous that the support element is connected by means of a positive connection with the end of the cup. The positive connection may in this case be configured by a bevel, a step, by a dovetail connection or the like. Additionally or alternatively, the support member may also be connected by at least partial injection into the end of the cup with the end of the cup. In this case, it is possible for the positive connection to be designed during the injection. The support member has a plurality of support arms for holding the support member at the end of the cup. There are in this case two or more holding arms are provided which allow reliable attachment of the support member at the end of the cup by, for example, counteracting holding forces are applied by the support arms.

It is advantageous here that the holding arms are each pressed with a bias against an outer side of the cup. The retaining arms can be designed bow-shaped and optionally engage in recesses on the outside of the cup.

It is also advantageous that the holding arms each have a barb, wherein each barb engages behind a provided on an outer side of the cup stage. In this way, a latching connection can be configured, which allows easy mounting of the support member on the cup and, among other things, ensures a transport safety.

It is also advantageous that a hold-down spring is provided, which is connected to the support element. For example, the support element may be stamped on the hold-down spring.

Brief description of the drawings

• Fig. 1 ein System mit einem Brennstoffverteiler und einem Brennstoffeinspritzventil in einer schematischen Darstellung entsprechend einem ersten nicht beanspruchten Beispiel;
• Fig. 2 ein Stützelement eines Systems in einer schematischen Darstellung entsprechend einem Ausführungsbeispiel der Erfindung;
• Fig. 3 das in Fig. 2 dargestellte Stützelement in einer schematischen Schnittdarstellung entlang der mit III bezeichneten Schnittlinie entsprechend einer möglichen Ausgestaltung der Erfindung;
• Fig. 4 das in Fig. 2 dargestellte Stützelement in einer schematischen Schnittdarstellung entlang der mit III bezeichneten Schnittlinie entsprechend einer weiteren möglichen Ausgestaltung der Erfindung;
• Fig. 5 ein Stützelement in einer schematischen Schnittdarstellung entsprechend einem nicht beanspruchten Beispiel;
• Fig. 6 eine auszugsweise, schematische Schnittdarstellung des in Fig. 1 gezeigten Brennstoffverteilers entsprechend einem weiteren nicht beanspruchten Beispiel und
• Fig. 7 den in Fig. 6 auszugsweise dargestellten Brennstoffverteiler in einer schematischen Schnittdarstellung entsprechend einem noch weiteren nicht beanspruchten Beispiel.

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 a system with a fuel distributor and a fuel injection valve in a schematic representation according to a first unclaimed example;
• Fig. 2 a support member of a system in a schematic representation according to an embodiment of the invention;
• Fig. 3 this in Fig. 2 illustrated support member in a schematic sectional view along the designated III cutting line according to a possible embodiment of the invention;
• Fig. 4 this in Fig. 2 illustrated support member in a schematic sectional view along the designated III cutting line according to another possible embodiment of the invention;
• Fig. 5 a support member in a schematic sectional view according to a non-claimed example;
• Fig. 6 a partial, schematic sectional view of the in Fig. 1 shown fuel distributor according to another example not claimed and
• Fig. 7 the in Fig. 6 in excerpts shown fuel distributor in a schematic sectional view according to yet another example not claimed.

Embodiments of the invention

Fig. 1 shows a system 1 with a fuel distributor 2, a fuel injection valve 3 and a support member 4. The system 1 in this case comprises a hold-down spring 5. The fuel distributor 2 is not necessarily part of the system 1. In particular, the system 1, the fuel injection valve 3, the support member 4 and the hold-down spring 5, but not the fuel distributor 2 comprise and are manufactured and sold in this way as a system 1. On the other hand, the fuel distributor 2 may also comprise the support element and optionally also the hold-down spring 5 and be manufactured and distributed to this extent. Further, the system 1 may also be configured as a fuel injection system 1, which comprises the fuel distributor 2, the fuel injection valve 3, the support member 4, the hold-down spring 5 and optionally further components.

The fuel distributor 2 and the system 1 are particularly suitable for a fuel injection system which is operated with a medium pressure. In this case, a fuel is preferably in a range of 3 MPa to 10 MPa or 30 bar promoted to 100 bar in the fuel distributor 2. In particular, the mean pressure may be in the range of 5 MPa to 7 MPa or 50 bar to 70 bar. However, the fuel distributor 2 according to the invention and the system 1 are also suitable for other applications.

The fuel distributor 2 of the first example has a distributor body 10 which comprises a distributor tube 11 and a plurality of cups 12 arranged next to one another on the distributor tube 11. Here is in the Fig. 1 only the cup 12 is shown. Via a connection 13, which can be configured in accordance with a high-pressure connection, fuel under the medium pressure can be guided into a fuel space 14 provided in the interior of the distributor tube 11. Via a channel, the fuel from the fuel chamber 14 can be guided to the fuel injection valve 3 fixed in the cup 12. Here, an inlet-side end 15 of the fuel injection valve 3 is at least partially inserted into the cup 12. In operation, the fuel can be injected at a combustion chamber end 16 of the fuel injection valve 3 via one or more nozzle openings in a combustion chamber of an internal combustion engine.

In the mounted state, the fuel distributor 2 is in a fixed position at a certain distance from the internal combustion engine, not shown. The fuel injection valve 3 is in this case fixed between the cup 12 of the fuel distributor 2 and a cylinder bore of the internal combustion engine. The hold-down spring 5 is biased during assembly, so that a biasing force acts on the fuel injection valve 3, which holds the fuel injection valve 3 against the cylinder head. For example, the fuel injection valve 3 may be held down with a biasing force of about 500 N in the cylinder head.

The distributor body 10 of the fuel distributor 2 and the cup 12 are formed from a plastic. Here, the cup 12 is an integral part of the distributor body 10. For example, the distributor body 10 may be configured with the cup 12 as an injection molded part. On the cup 12, the support member 4 is arranged. Here, the support member 4 forms a support surface 17 at one end 18 of the cup 12th

In the fuel distributor 2 of the first example, the support element 4 is designed as an annular or partially annular support element 4 and connected to the end 18 of the cup 12. The support element 4 is thus part of the fuel distributor 2 of the first example In the system 1 of the first example, a main body 20 is provided at the upstream end 15 of the fuel injection valve 3, which receives the hold-down spring 5. Here, the base body 20 may be placed from the inlet end 15 to the rest of the fuel injection valve 3. The base body 20 can be detachably or non-detachably connected to the other components of the fuel injection valve 3.

The hold-down spring 5 has an arc portion 21, which serves as a curved contact portion 21 in this embodiment. Here, a contact between the arc portion 21 and the support surface 17 of the support member 4 is formed. During assembly, the arcuate contact portion 21 can in this case be moved relative to the support surface 17 in order to allow a biasing of the hold-down spring 5.

In the assembled state, the hold-down spring 5 exerts a hold-down force on the fuel injection valve 3, which causes a correspondingly large counterforce on the support member 4. The support member 4 distributes this force evenly across the end 18 of the cup 12. Thus, the surface pressure at the end 18 of the cup 12 is prevented from exceeding the allowable range. Thus, a flow of the plastic is prevented and it is ensured that the required tolerances. Creep of the plastic in the region of the contact point is therefore prevented.

Thus, the bias of the hold-down spring 5 can be distributed over a large area and the surface pressure can be greatly reduced. Thus, a flow of the plastic is prevented and the cup 12 holds, in particular at its end 18, the predetermined shape and the predetermined tolerances.

In a further embodiment of the fuel distributor 2, the hold-down spring 5 may be connected to the support element 4. For example, the ring-shaped support element 4 can be directly impressed on the hold-down spring 5. In a preassembly is then the annular disk-shaped support member 4 via the hold-down spring 5 on the base body 20. Specifically, the support member 4 can be fixed to the fuel injector 3 and reach during assembly to the fuel distributor 2 in the position at the end 18 of the cup 12 , The freedom of movement required for the prestressing of the hold-down spring 5 can be achieved here by a suitable design of the support element 4 and / or of the base body 20.

In a further possible embodiment, the support member 4 may be connected to the hold-down spring 5 and at the same time fixed to the fuel distributor 2. In this case, the hold-down spring 5 is biased against the fuel injection valve 3 during mounting.

Fig. 2 shows a support member 4 of a system 1 and a fuel distributor 2 according to an embodiment of the invention in a schematic representation. The support member 4 in this case comprises a support ring 23 and a plurality of support arms 23, 24, 25, 26. About the support arms 23 to 26 is a fixing of the support member 4 on an outer side 27 (FIGS. Fig. 1 ) of the cup 12 allows.

Possible embodiments of the support arms 23 to 26 are based on 3 and 4 described in more detail.

Fig. 3 shows that in Fig. 2 illustrated support member 4 in a schematic sectional view along the designated III cutting line according to a possible embodiment of the invention. Here, arc sections 28, 29, 30 of the holding arms 23, 24, 26 are shown, which are bent to the outside 27 of the cup 12 out.

When mounting the support member 4 to the cup 12, the arcuate portions 28, 29, 30 of the support arms 23, 24, 26 are biased radially outwardly. Accordingly, the holding arm 25 is configured, which also has an arc portion which is biased. In the assembled state, the support element 4 is thus held at the end 18 of the cup 12. Optionally, 12 recesses, ribs or the like may be provided on the outside 27 of the cup to improve the fixation.

Fig. 4 shows that in Fig. 2 shown supporting element 4 in a schematic sectional view along the designated III cutting line according to another possible embodiment of the invention. In this embodiment, barbs 31, 32, 33 are provided at the ends of the holding arms 23 to 26, which engage behind a provided on the outer side 27 of the cup 12 stage. During assembly, the holding arms 23 to 26 are slightly spread out until the barbs 31, 32, 33 and a barb provided on the holding arm 25 hook behind the intended step. Thus, an attachment of the support member 4 is given to the fuel distributor 2.

Fig. 5 shows a support member 4 and the cup 12 of a fuel distributor 2 in an excerpt, schematic sectional view according to another example not claimed. In this example, the support member 4 on a support ring 22, on which the support surface 17 is configured. Furthermore, at the Support member 4 a plurality of tongues 40, 41 are provided, each engage behind a provided on the outer side 27 of the cup 12 stage 42, 43. The steps 42, 43 are formed in this example by recesses 44, 45 provided on the outside 27 of the cup 12. For example, during assembly, the support element 4 can first be placed on the end 18 of the cup 12. Subsequently, the tongues 40, 41 can be pressed radially inwards into the depressions 44, 45, so that the engagement of the steps 42, 43 is achieved. The tongues 40, 41 then engage in the depressions 44, 45 provided on the outside 27 of the cup 12.

In a similar way, in the basis of the Fig. 4 described embodiment, the barbs 32, 33 of the support arms 24, 26 which engage on the outside of the cup 12 provided steps 42, 43 to achieve the attachment.

Thus, the secure hold of the support member 4 can be achieved on the cup 12 of the manifold body 10 by positive engagement. The positive connection can for example via the tongues 40, 41 or barbs 31, 32, 33 come about.

But even without a form fit can be done by a corresponding bias fastening of the support member 4 to the cup 12 of the manifold body 10, as for example with reference to Fig. 3 is described.

The tongues 40, 41 of the support element 4 can be configured, for example, by notches 40, 41. However, there are also other scratches or the like conceivable.

Fig. 6 shows the in Fig. 1 shown fuel distributor 2 in a partial, schematic sectional view corresponding to another example not claimed. In this example, the support element 4 is configured as an annular or partially annular support element 4. On the support member 4, the support surface 17 is provided for the hold-down spring 5. The cup 12 has at its end 18 a collar 50, which has radially outwardly directed lugs 51, 52 in section. The collar 50 forms a positive connection with the correspondingly configured support element 4. In addition, the support member 4 can be injected into the end 18 of the cup 12. For example, the collar 50 can be configured by a spraying process, wherein the support element 4 is positioned at the end 18 during the injection process.

Fig. 7 shows the in Fig. 6 shown fuel distributor 2 in a partial, schematic sectional view corresponding to another example not claimed. In this example, the annular or partially annular support element 4 has an at least approximately rectangular cross-section. Here, the support element 4 is inserted into a rectangular recess 53 at the end 18 of the cup 12. The collar 50 engages from inside into the support element 4. The attachment between the support member 4 and the cup 12 in this case is preferably carried out by injecting the support member 4 in the end 18 of the cup 12. In this example, the connection is made without a positive connection. By sinking the annular or partially annular support member 4 in the end 18 of the cup 12, the emergence of a sharp edge is prevented. An optionally arranged on the inflow end 15 of the fuel injection valve 3 sealing ring which is inserted into the cup 12, can not be damaged. Here, the collar 50, which is formed from the plastic material of the cup 12, the insertion, over which the sealing ring is inserted into the cup 12.

The support element 4 is preferably formed from a metallic material. As a result, significant deformations can be avoided, in contrast to a conventional plastic even at high surface pressures.

Thus, especially a metallic support element 4 can be attached to the distributor body 10 formed of plastic.

The invention is not limited to the described embodiments.

Claims (6)

1. Fuel distributor (2), in particular for fuel injection systems of mixture-compressing, applied-ignition internal combustion engines, having a distribution body (10) in which a fuel chamber (14) is formed, and at least one support element (4), wherein at least one cup (12), on which the support element (4) is arranged, is provided on the distribution body (10), and wherein the support element (4) forms, at least in part, a support surface (17) on an end (18) of the cup (12),
   characterized
   in that the support element (4) has a planar support ring (22) which bears against the end (18) of the cup (12), wherein the support ring (22) has emanating therefrom a plurality of retaining arms (23, 24, 25, 26) which are provided with flexurally elastic arcuate portions (28, 29, 30) and are bent towards a circumferential outer side (27) of the cup (12), with the result that fixing of the support element (4) to the outer side (27) of the cup (12) is enabled by means of the retaining arms (23, 24, 25, 26).
2. Fuel distributor according to Claim 1,
   characterized
   in that the distribution body (10) and the cup (12) are formed from at least one plastic and the support element (4) is formed from a metallic material.
3. Fuel distributor according to Claim 1,
   characterized
   in that the support element (4) is connected to the end of the cup (12) by means of a form fit and/or in that the support element (4) is connected to the end (18) of the cup (12) by being at least partially injection-moulded into the end (18) of the cup (12).
4. Fuel distributor according to Claim 1,
   characterized
   in that the retaining arm (23 - 26) is pressed with a prestress against an outer side (27) of the cup (12).
5. Fuel distributor according to Claim 4,
   characterized
   in that the retaining arm (23 - 26) has a barb (31 - 33) which engages behind a step (42, 43) provided on an outer side (27) of the cup (12).
6. Fuel distributor according to one of Claims 1 to 5,
   characterized
   in that a hold-down spring (5) is provided which is connected to the support element (4).

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