EP3199794B1 - Fuel distribution rail and method for producing the same - Google Patents

Description

The invention relates to a fuel rail for a fuel injection for internal combustion engines in motor vehicles, in particular for gasoline engines. The invention further relates to a method for producing the fuel rail.

Fuel rail for the direct injection of gasoline are basically known in practice. They comprise a tube-like element with a fuel channel, from which fuel channel usually branch off three, four or even more outlet openings. The outlet openings are fluidly connected to a respective injection nozzle. The fuel rail also includes an inlet passage for supplying fuel to the fuel rail.

Here, the fluidic connection of the outlet openings with the respective injection nozzle designed as consuming. Thus, it is initially known in practice to provide a base tube which forms the fuel channel and then produce the outlet openings by means of bores along the base tube. At this outlet openings then individual connecting pieces are connected, each having a connection channel, which serves connection channel of the fluidic connection of the injection nozzle. Both the base pipe and the connecting pieces are made of steel according to this known from the prior art.

According to another embodiment of the known prior art, the fuel rail is a forging. However, this requires in the manufacturing process at least one bore per connection piece for generating the connection channel. Due to the required minimum length The connecting pieces are thus deep drilling required, which are expensive. These deep holes are particularly expensive due to the high tolerance requirements in terms of position and diameter, which makes the manufacturing process correspondingly more expensive.

The document DE 103 22 769 A1 describes a fixing strip with a support wall, wherein an extension of this investment wall has four holes. In these holes connecting pieces in the form of valve cups are used and soldered. The valve cups are also soldered at their upper end to the base tube. As a result, the fuel can reach the individual valve cups via a fuel channel of the base tube and corresponding outlet openings in the wall of the base tube. A disadvantage of this structure, however, is that when inserting the valve cups in the extension of the fixing strip are easily mispositioned. As a result, it requires a certain adjustment effort here. Furthermore, two soldering processes are required for each valve cup.

The invention is therefore the technical problem of providing a fuel rail, in which the above-mentioned disadvantage is avoided. In particular, the invention addresses the technical problem of specifying a fuel rail, in which the manufacturing cost is reduced.

To solve this technical problem, the invention teaches a fuel rail for fuel injection for internal combustion engines in motor vehicles, in particular for gasoline engines, comprising a base tube, the base tube having a extending in the longitudinal direction of the base tube fuel passage, wherein the base tube comprises at least two outlet openings, wherein the outlet openings from the fuel channel branch off, wherein a connecting element is arranged on the base tube, wherein the connecting element has a voltage applied to the base tube abutment wall, wherein the connecting element is integrally connected to the base tube, wherein the connecting element has at least two connecting pieces, wherein the connecting pieces each have a connection channel for fluidic connection ever an outlet opening each having an injection nozzle and wherein the connecting pieces are integrally connected to the abutment wall.

The invention is based on the finding that a decoupling of the fuel channel and the connecting piece at the beginning of the manufacturing process is very advantageous. The decoupling is accomplished by the fact that the fuel channel is formed by the base tube and the connecting pieces are attached to the base tube only in a later manufacturing step. The connecting pieces are arranged on the connecting element, which connecting element is firmly bonded and preferably by means of soldering to the base tube. This decoupling has the advantage that initially only the outlet openings are produced by means of bores on the base tube. These holes only need to penetrate the wall thickness of the base pipe, so that a deep drilling process is not required here. As a result, even very high tolerance requirements in terms of position and diameter of the outlet openings are much less expensive. The connection channels can z. B. be made by deep drilling, but then expediently the connection channels have a correspondingly large diameter, so that in this respect only small tolerance requirements must be met. The production cost is thus significantly reduced.

According to a particularly preferred embodiment, the connection element comprises steel and advantageously an austenitic steel. The steel of the connection element preferably has an austenitic structural constituent and is advantageously a duplex steel. Conveniently, the connection element and / or the base tube comprises a steel corrosion-resistant against fuel. The base tube may be seamless or double or multi-walled.

Particularly preferably, the connection element is firmly bonded and preferably fixed to the base tube by means of soldering, particularly preferably by means of brazing and very particularly preferably by means of high-temperature brazing. It is possible that the connection element is attached by welding to the base tube.

According to a preferred embodiment, the connection element comprises a forging part and advantageously a drop forging part. Conveniently, the connection element has a ridge or burrs or deburred places. It is preferred that the connection element is formed at least predominantly and preferably completely integrally. The term "integral" means in particular the production of a forged part or a cast. According to one embodiment, the connection element comprises one and preferably only one casting. The casting preferably comprises cast iron.

It is preferred that the connection element encloses the base tube at least in sections and preferably along the entire length of the base tube only partially, preferably at most around 350 °, preferably at most around 270 ° and particularly preferably at most around 190 °. In a specific embodiment, the base tube and the connecting element are formed such that the base tube can be inserted into the connecting element due to the partial enclosing of the connecting element. Very advantageously, the connection element has two edges which run parallel to the longitudinal axis of the base tube and form an end of the connecting element in the circumferential direction and which edges preferably form part of the abutment wall. It is preferred that the two edges extend at least along 50%, 75% and 100% of the length spanned by the outlet openings. Advantageously, a respective weld seam is arranged along the two edges. It is expedient that the connecting element in each case has an arcuate edge at its own ends facing the base tube ends, along which arcuate edges expediently a respective weld seam is arranged.

It is within the scope of the invention that a longitudinal axis of at least one connecting piece or a connecting channel intersects the longitudinal axis of the fuel channel. In other words, it is expedient that a longitudinal axis of at least one connection channel or connection piece lies in a plane with the longitudinal axis of the fuel channel. This condition is considered fulfilled if the longitudinal axis of the connection channel or connecting piece does not pass by more than +/- 10% from the inner diameter of the base tube on the longitudinal axis of the fuel channel. It is particularly preferred if the longitudinal axis of the fuel channel and the longitudinal axis of at least one connecting piece or connecting channel lie in one plane and enclose a substantially rectangular angle relative to one another.

It is within the scope of the invention that at least one of the connecting pieces has an inner wall, which inner wall forms the connecting channel, wherein the inner wall is formed integrally with the at least one connecting piece and wherein the inner wall is the innermost wall. It is preferred that the inner wall can be brought into contact with the fuel. Appropriately, is the connecting piece formed integrally. In particular, the connecting piece is designed so that it has no inner sleeve.

According to a preferred embodiment, at least one connecting piece is assigned at least one connecting piece, which connecting piece extends at least in sections parallel to the at least one connecting piece. Preferably, the connecting piece runs along its predominant length parallel to the connecting piece. Conveniently, the at least one connecting piece is part of the connecting element and preferably a portion of the forging or casting. Particularly preferably, the connection piece is formed integrally with the connection element. It is expedient that the connecting piece and the connection piece share at least one common wall. Conveniently, the end facing away from the base tube of the at least one connecting piece is aligned with an end of the connecting piece facing away from the base tube. It is expedient that a longitudinal axis of the connecting piece does not intersect the base tube. It is preferred that an end of the connecting piece facing the base tube is aligned with an edge of the connecting element running parallel to the longitudinal axis of the fuel channel. The connecting piece conveniently has a passage opening along its longitudinal axis.

It is advantageous if the base tube has a wall thickness of at least 1.0 mm, preferably of at least 1.5 mm and particularly preferably of at least 2 mm. Conveniently, a wall thickness of the base tube is at most 15 mm, preferably at most 10 mm and particularly preferably at most 7 mm. The inner diameter of the base tube is advantageously at least 8 mm, preferably at least 12 mm and particularly preferably at least 15 mm. The base tube preferably has an inner diameter of not more than 60 mm, preferably not more than 50 mm and more preferably not more than 40 mm.

According to a preferred embodiment, the abutment wall comprises at least one window-like opening. Conveniently, the connecting element between the at least two connecting pieces on an intermediate region. The intermediate region preferably comprises only a part of the abutment wall. The intermediate region is particularly preferably designed like a partial shell and expediently connects the two connecting pieces. According to a preferred embodiment, the intermediate region comprises at least two window-like openings, wherein the window-like openings are expediently separated from one another by a web.

According to a particularly preferred embodiment, at least one of the diameters of the connection channels is at least a factor of 1.2, preferably 1.5 and particularly preferably 2.0 greater than the diameter of the associated outlet opening. A diameter of at least one or all outlet openings is expediently at least 1.0 mm, preferably at least 1.5 mm and particularly preferably at least 2.0 mm. At least one or all outlet openings expediently have a diameter of at most 20 mm, preferably of at most 15 mm and particularly preferably of at most 10 mm. A diameter of the connecting channels is expediently at least 4 mm, preferably at least 6 mm and particularly preferably at least 8 mm. The connection channels expediently have a diameter of at most 50 mm, preferably of at most 35 mm and particularly preferably of at most 25 mm.

It is preferred that the connecting pieces or connecting channels only each have a longitudinal axis. It is preferred that none of the connection channels is bent or angled. If the connecting pieces or connecting channels only each have a longitudinal axis, so hereby any connecting pieces or connection channels are excluded, which are designed bent or angled.

It is particularly advantageous if the fuel rail is designed so that it can be subjected to pressures of at most 1500 bar, preferably up to at most 1000 bar and more preferably up to at most 700 bar. Conveniently, the fuel rail is designed so that it is only suitable for gasoline engines. It is preferred that the fuel rail can easily withstand the usual pressures in gasoline engines, but not the usual pressures in diesel engines.

The invention further provides a method for producing a fuel rail, in particular a fuel rail according to the invention, wherein a base tube is provided with a extending in the longitudinal direction of the base tube fuel passage, wherein at least two outlet openings are drilled in the base tube, so that the outlet openings branch off from the fuel channel wherein a connection element is arranged on the base tube, so that a contact wall of the connection element rests against the base tube, wherein the connection element is integrally connected to the base tube, wherein the connection element has at least two connection pieces, wherein the connection pieces each have a connection channel for the fluidic connection of one Having outlet opening, each with an injection nozzle and wherein the connecting pieces are integrally connected to the plant wall.

According to a preferred embodiment, the connection element is produced by forging and more preferably by drop forging. According to one embodiment, the connection element is produced by casting. Particularly preferably, the connection element is connected by means of soldering material fit with the base tube. Preferably, the connection element is connected to the base tube by means of brazing and particularly preferably by means of high-temperature brazing. However, the connection element can also be fastened to the base tube by means of welding.

Fig. 1

eine perspektivische Ansicht eines Basisrohres einer erfindungsgemäßen Kraftstoffverteilerleiste,

Fig. 2

eine perspektivische Ansicht eines Anschlusselementes der Kraftstoffverteilerleiste und

Fig. 3

eine perspektivische Ansicht der zusammengebauten Kraftstoffverteilerleiste, umfassend das Basisrohr aus Fig. 1 und das Anschlusselement aus Fig. 2.

The invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. It show in a schematic representation

Fig. 1

a perspective view of a base tube of a fuel rail according to the invention,

Fig. 2

a perspective view of a connecting element of the fuel rail and

Fig. 3

a perspective view of the assembled fuel rail, comprising the base tube Fig. 1 and the connection element Fig. 2 ,

In Fig. 1 is a base tube 1 of a fuel rail according to the invention shown. The base tube 1 has a fuel channel 2 extending in the longitudinal direction of the base tube 1. From this fuel channel 2 branch off a total of four outlet openings 3 with a diameter of for example 4 mm. Due to the perspective view can not be seen that on the back of the base tube 1 is still an inlet opening.

The base tube 1 consists of an austenitic steel, has a wall thickness of z. B. 3 mm and an exemplary inner diameter of 20 mm.

In Fig. 2 is a connection element 4 can be seen, which on the base tube 1 from Fig. 1 is put on. In this case, each outlet opening 3 of the base tube 1 is assigned a connection piece 6. The connecting pieces 6 connect the outlet openings 3 and thus the fuel channel 2 fluidly with the respective injection nozzles, not shown, via connecting channels 7. The connecting piece 6 is in each case assigned a connecting piece 8, wherein the longitudinal axes of the connecting piece 8 extend parallel to the longitudinal axes of the connecting piece 6. Each connecting piece 8 touches its associated connection piece 6 so that they share a common wall. An inner diameter of the connecting piece 6 and a diameter of the connecting channels 7 is for example 12 mm.

The connection element 4 is designed so that it can rest against the base tube 1, for which purpose it has a contact wall 5. In this exemplary embodiment, the abutment wall 5 has, between the four connecting pieces 6, an intermediate region 12 which is made relatively thin. The strength of the investment wall 5 in the intermediate regions 12 is z. B. 3 mm. Furthermore, each of the three intermediate regions 12 has two windows 9, which are separated from each other by a web 13. The connection element 4 ideally consists entirely of an austenitic steel. Thus, in particular, the connecting piece 6 and the connecting piece 8 are integrally connected to the plant wall 5. The terminal of this embodiment was made by swaging. In a subsequent step, the connection channels 7 are produced by drilling or deep drilling.

The base tube 1 and the connection element 4 are assembled by means of soldering. Such a fuel rail is made in Fig. 3 displayed. The base tube 1 has been closed at the ends by means of plugs 10. Further, an inlet nozzle 11 has been soldered to the base tube 1, so that a fluidic connection of the inlet opening with a fuel line, not shown, is possible.

Claims (14)

1. A fuel distributor bar for a fuel injector for internal combustion engines in motor vehicles, in particular for spark ignition engines, comprising a base pipe (1), wherein the base pipe (1) has a fuel duct (2) extending in the longitudinal direction of the base pipe (1), wherein the base pipe (1) comprises at least two outlet openings (3), wherein the outlet openings (3) branch from the fuel duct (2), wherein a connecting element (4) is arranged on the base pipe (1), wherein the connecting element (4) has a bearing wall (5) that abuts against the base pipe (1), wherein the connecting element (4) is integrally bonded with the base pipe (1), wherein the connecting element (4) has at least two pipe unions (6), wherein the pipe unions (6) each have a connecting duct (7) for fluidically connecting a respective outlet opening (3) with a respective injection nozzle,
   characterized in that
   the pipe unions (6) are integrally connected with the bearing wall (5).
2. The fuel distributor bar according to claim 1, wherein the connecting element (4) has steel.
3. The fuel distributor bar according to one of claims 1 or 2, wherein the base pipe (1) has steel.
4. The fuel distributor bar according to one of claims 1 to 3, wherein the connecting element (4) is fastened to the base pipe (1) via soldering.
5. The fuel distributor bar according to one of claims 1 to 4, wherein the connecting element (4) only partially envelops the base pipe (1) over at least a longitudinal section.
6. The fuel distributor bar according to one of claims 1 to 5, wherein a longitudinal axis of at least one of the pipe unions (6) lies in a plane with the longitudinal axis of the fuel duct (2).
7. The fuel distributor bar according to one of claims 1 to 6, wherein at least one of the pipe unions (6) has an interior wall, wherein the interior wall forms the connecting duct (7), wherein the interior wall is integrally designed with the at least one pipe union (6), and wherein the interior wall is the innermost wall.
8. The fuel distributor bar according to one of claims 1 to 7, wherein a pipe union (6) is allocated to at least one connecting piece (8), wherein the connecting piece (8) at least sectionally runs parallel to the at least one pipe union (6).
9. The fuel distributor bar according to one of claims 1 to 8, wherein the base pipe (1) has a wall thickness of at least 1.0 mm, preferably of at least 1.5 mm, and especially preferably of at least 2.0 mm.
10. The fuel distributor bar according to one of claims 1 to 9, wherein the pipe union (4) comprises a forged part.
11. The fuel distributor bar according to one of claims 1 to 10, wherein the bearing wall (5) comprises at least one window-like opening (9).
12. The fuel distributor bar according to one of claims 1 to 11, wherein the inner diameter of one of the connecting ducts (7) is larger than the diameter of the allocated outlet opening (3) by at least a factor of 1.2, preferably of 1.5, and especially preferably of 2.0.
13. The fuel distributor bar according to one of claims 1 to 12, wherein the pipe unions (6) or connecting ducts (7) each only have one longitudinal axis.
14. A method for manufacturing a fuel distributor bar, in particular a fuel distributor bar according to one of claims 1 to 13, wherein a base pipe (1) with a fuel duct (2) extending in the longitudinal direction of the base pipe (1) is provided, wherein at least two outlet openings (3) are drilled into the base pipe (1), so that the outlet openings (3) branch from the fuel duct (2), wherein a connecting element (4) is arranged on the base pipe (1), so that a bearing wall (5) of the connecting element (4) abuts against the base pipe (1), wherein the connecting element (4) has at least two pipe unions (6), wherein the pipe unions (6) each have a connecting duct (7) for fluidically connecting a respective one outlet opening (3) with a respective one injection nozzle,
    characterized in that
    the pipe unions (6) are integrally connected with the bearing wall (5).

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