EP1522687B1 - Air gap manifold - Google Patents

Abstract

The manifold has an interior part (1) with exhaust gas guides (2, 3, 4) plugged into one another with a sliding fit, and an exterior part (5) surrounding the inner part. An air-gap (6) is formed between the interior part and the exterior part, and effects a heat insulation of an exhaust manifold. The exhaust gas guides are formed by half-shells which are connected to one another by common reshaping at a rim side. An independent claim is also included for a method of manufacturing an air-gap manifold.

Description

The present invention relates to an air gap manifold for connecting exhaust gas outlet openings of an internal combustion engine, in particular motor vehicle engine, with an exhaust inlet opening of an exhaust system, with an inner part with a plurality of push-fit into each other exhaust ducts, a surrounding the inner part, gas-tight outer part and an existing between the inner part and outer part air gap. An example of such an air gap bend is in EP 0 582 985 A shown.

There are various ways to produce such air gap manifold. Conventional pipe elbows, the pipes can be produced with very high accuracy by hydroforming. However, such manufacturing methods are relatively expensive. On the other hand, it is necessary that the manifold are designed to be absolutely gas-tight to the outside to comply with the increasingly stringent emissions regulations.

The invention has for its object to provide an air gap bend of the type mentioned, on the one hand is low in the production and on the other hand allows compliance with the emissions regulations.

This object is achieved in that the exhaust ducts of the inner part are at least partially formed by shells, which by common Edge forming, in particular folding, are connected together.

The formation of the exhaust ducts of the inner part of shells is particularly inexpensive to manufacture. On the one hand, the shells can be pulled cheaply. On the other hand, the connection of the shells by common edge-side forming, in particular folding, particularly favorable in the production. Especially compared to welded joints results in a great cost advantage, especially when exhaust manifolds for turbocharger must be manufactured without welding spatter. Only expensive laser and TIG welding techniques can then be considered. The forming compound of the shells according to the invention is for a sweat-spatter and on the other hand with little effort feasible. The tightness of the forming connection between the shells is sufficient, since the outer shell of the manifold is absolutely gas-tight and therefore a small leakage of the inner part does not cause problems.

Another cost saving results, even if the outer part consists of shells. Also, the outer part can then be made relatively inexpensive. In addition, the assembly of the manifold is simplified.

As a material for the shells of the inner part and / or the outer part in particular sheet comes into consideration. The sheet thickness of the inner part can be kept relatively low, since no minimum thickness required for the forming connection of the shells other than welding is. As a result, various types of steel, for example, austenitic steel can be used.

In order to ensure a sufficient rigidity of the exhaust ducts despite thin material thickness, the shells of the inner part may be provided with beads. Also, the shells of the outer part may have beads to increase the rigidity.

The shells of the outer part are preferably welded together. Hereby, a high tightness can be ensured. The welded joints can be arranged on the outside, so that there is no risk of contamination of the interior of the exhaust manifold. It can also be used more cost-effective welding processes.

In order to prevent displacement of the shells of the inner part in use, the inner shells can be locked by individual welds against each other. Since only a few spot welds are required to reliably prevent displacement, simple spot welds can be used without undue cost increase. Alternatively or additionally, the shells can be embossed together.

The outer part preferably consists of two half-shells. Likewise, the exhaust passages of the inner part preferably each consist of two half-shells. For a particularly favorable production and installation is possible. Also, it has been found to be advantageous to arrange the parting planes of the inner shells and the outer shell approximately at right angles to each other.

A particularly advantageous use of the air gap bend according to the invention is given in internal combustion engines with a turbocharger, since the manifold according to the invention can be made particularly inexpensive welding spatter free.

The preparation of the air-gap bend according to the invention is carried out such that first the one part of the exhaust ducts forming shells of the inner part are inserted into each other according to the desired sliding seat arrangement, then the respective other part of the exhaust ducts forming shells also, and then only the associated shells of the exhaust pipes together be joined together by pairs together edge formed, in particular folded.

According to the invention, therefore, the individual exhaust ducts are not first composed of, for example, two shells and then inserted the exhaust ducts formed in one another, but the nesting is done separately for each half of the inner part, and only then the two halves of all exhaust ducts of the inner part are simultaneously connected. In this way it can be ensured that the cross sections of the exhaust ducts in the sliding seat areas are adapted to each other. Problems when joining the exhaust ducts do not occur, and even during operation, a problem-free displacement of the individual exhaust ducts against each other can be ensured.

After connecting all nested dishes by common edge-side forming, in particular folding, the shells of the respective exhaust ducts are locked if necessary by welding points against each other. Then, the inner part is inserted into the shells of the outer part and these are connected in a gas-tight manner by welding.

The shells of the inner part are preferably made of sheet metal, in particular by deep drawing. Preferably beads are embossed in order to increase the rigidity of the shells. In particular, two half shells are manufactured per exhaust guide, which are then connected to each other simultaneously with the other half shells.

Fig. 1

eine Draufsicht auf einen erfindungsgemäßen Luftspaltkrümmer mit entfernter oberer Außenschale,

Fig. 2

einen Schnitt durch den Luftspaltkrümmer von Fig. 1 gemäß Linie A-A,

Fig. 3

einen Schnitt durch den erfindungsgemäßen Luftspaltkrümmer gemäß Linie C-C in Fig. 2 und

Fig. 4

die Einzelheit B von Fig. 3 in vergrößerter Darstellung.

A non-limiting embodiment of the invention is shown in the drawing and will be described below. They show, in each case in a schematic representation,

Fig. 1

a plan view of an air gap bend according to the invention with removed upper outer shell,

Fig. 2

a section through the air gap manifold of Fig. 1 according to line AA,

Fig. 3

a section through the air gap according to the invention according to line CC in Fig. 2 and

Fig. 4

the detail B of Fig. 3 in an enlarged view.

The illustrated air gap manifold comprises an inner part 1 with a plurality of push-fit into each other inserted exhaust ducts 2, 3 and 4 and a surrounding the inner part 1 at a distance, gas-tight outer part 5. Between inner part 1 and outer part 5 is thereby formed an air gap 6, the heat insulation of Exhaust manifold causes.

The exhaust ducts 2, 3 and 4 are each formed of two half-shells 2a and 2b, 3a and 3b, 4a and 4b, which are connected to one another at the edge. The connection is a folded connection, as in Fig. 4 is shown. For this purpose, the edge of one half-shell 3a is bent around the edge of the other half-shell 3b. Subsequently, the fold 7, as shown in phantom, inclined to increase the strength of the connection.

The exhaust ducts 2, 3 and 4 are, as I said, inserted into each other with sliding fit. For this purpose, the fold ends 7 at one end 2 ', 3' of the exhaust ducts 2 and 3 before the end of the respective exhaust duct 2, 3. Thus, a falzfreier area 8 is formed, to which the associated end 3 ", 4" of each adjacent Exhaust guide 2, 3 and 4 is arranged with sliding seat.

The other end 2 "of the exhaust gas guide 2 is connected in a gastight manner together with the outer shell 5 to a first inlet flange 9. A second inlet flange 10 is gas-tightly connected to the outer shell 5 and the end 11 'of a lateral branch 11 of the exhaust gas guide 3. Third and fourth inlet flanges 12, 13 are finally gas-tightly connected to the outer shell 5 and each of a rigid sleeve 14, 14 ' with a sliding fit in a lateral branch 15 of the exhaust gas guide 4 and the sleeve 14 'likewise with a sliding fit in the second end 4' of the exhaust gas guide 4.

The exhaust gas guide 4 has a second branch 16, in which a further sleeve 17 is inserted with sliding seat. This sleeve 17 is connected in a gastight manner with an outlet flange 18 together with the outer part 5. At the outlet flange 18, a continuing pipe of a conventional exhaust system can be connected. Accordingly, the inlet flanges 9, 10, 12 and 13 can be connected to exhaust gas outlet openings of an internal combustion engine.

The outer part 5 also has two half shells 5a, 5b. However, the parting plane I of the half-shells 5a and 5b extends at an angle of approximately 90 ° to the parting plane II of the half-shells 2a, 2b, 3a, 3b, 4a and 4b of the inner part 1, and approximately parallel to the plane of the flanges 9, 10th , 12 and 13.

The production of the illustrated air-gap bend essentially takes place in such a way that firstly all half shells 2a, 2b, 3a, 3b, 4a and 4b of the inner part 1 and 5a and 5b of the outer part 5 are produced. In this case, beads 19 can be introduced into the half shells. Then, each one half shells 2a, 3a and 4a of the inner part 1 are inserted into each other according to the desired sliding seat arrangement. Accordingly, the half-shells 2b, 3b and 4b of the inner part 1 are inserted into one another. After inserting the sleeves 14 and 14 ', the nested shells 2a, 3a and 4a and 2b, 3b and 4b are inserted into a forming tool. Then all the half-shells assigned to each other become 2a, 2b, 3a, 3b and 4a, 4b connected by edge-side folding. If necessary, the half-shells 2 a, 2 b, 3 a, 3 b, 4 a and 4 b of the inner part 1 are locked against each other by individual welding points. Here, a laser or MAG welding technique is used to avoid harmful spatter.

The inner part is finished and is used after removal from the forming tool in the lower shell 5b of the outer part 5. Together with this, the inner part 1 is then gas-tightly connected to the inlet flanges 9, 10, 12 and 13, in particular welded. Then, the sleeve 17 is welded gas-tight together with the upper shell 5a of the outer part 5 with the outlet flange 18. Subsequently, the upper shell 5a of the outer part 5 is placed on the lower shell 5b and welded gas-tight in the overlapping region. The two half-shells 5a, 5b of the outer part 5 can be connected to each other by normal welding methods, since the weld is on the outside.

By the described manufacturing method can be made between the exhaust gas ducts 2, 3 and 4 sliding seat connections, which may have a very tight fit despite the construction of the exhaust ducts 2, 3 and 4 of half shells. Since the exhaust ducts 2, 3 and 4 do not have to be inserted into one another in the folded state, there are also no problems due to uneven curves or cross sections of the mutually associated ends 2 ', 3 "and 3', 4" of the exhaust ducts 2, 3 and 4.

The illustrated and described embodiment of the inner part with sliding seats allows otherwise in a known manner a substantially unhindered thermal expansion of the exhaust ducts 2, 3 and 4 of the Inner part 1, in particular a greater thermal expansion due to the greater heating of the inner part 1 relative to the outer part 5. The outer part 5 on the other hand ensures a high gas-tightness of the air-gap bend. In this way, a well-fit air-gap manifold can be produced at a relatively low cost.

LIST OF REFERENCE NUMBERS

1

inner part

2

exhaust system

2 '

End of 2

2 '

End of 2

2a

half shell

2 B

half shell

3

exhaust system

3 '

End of 3

3 '

End of 3

3a

half shell

3b

half shell

4

exhaust system

4 '

End of 4

4 '

End of 4

4a

half shell

4b

half shell

5

outer part

5a

half shell

5b

half shell

6

air gap

7

fold

8th

non-rebound area

9

inlet flange

10

inlet flange

11

Turn off from 3

11 '

End of 11

12

inlet flange

13

inlet flange

14, 14 '

shell

15

Branch of 4

16

Branch of 4

17

shell

18

output flange

19

Beading

I

parting plane

II

parting plane

Claims (10)

1. An air-gap manifold for the connection of exhaust gas outlet openings of an internal combustion engine, in particular of a motor vehicle engine, to an exhaust gas intake opening of an exhaust gas system, having an interior part (1) formed at least in part by shells (2a, 2b, 3a, 3b, 4a, 4b) which are connected to one another by common reshaping at the rim, having an exterior part (5) likewise formed at least in part by shells (5a, 5b), surrounding the inner part (1) and made gas-tight, and having an air-gap (6) present between the interior part (1) and the exterior part (5),
   characterized in that
   the interior part includes a plurality of exhaust gas guides (2, 3, 4) formed by the shells (2a, 2b, 3a, 3b, 4a, 4b) and plugged into one another with a sliding fit; and in that the shells (5a, 5b) forming the exterior part are welded to one another.
2. An air-gap manifold in accordance with claim 1, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part (1) are connected to one another by folds.
3. An air-gap manifold in accordance with claim 1 or claim 2, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part (1) and/or the shells (5a, 5b) of the exterior part (5) consist of sheet metal and/or beads.
4. An air-gap manifold in accordance with claim 3, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part are latched to one another, in particular by individual spot welds.
5. An air-gap manifold in accordance with any one of the preceding claims, characterized in that the exterior part (5) consists of two half-shells (5a, 5b).
6. An air-gap manifold in accordance with any one of the preceding claims, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part (1) are half-shells, with the separation plane (I) of the exterior shell (5) and the separation plane (II) of the interior shell (1) preferably standing approximately at right angles to one another.
7. An air-gap manifold in accordance with any one of the preceding claims, characterized by the use for an internal combustion engine with a turbocharger.
8. A method for the manufacture of an air-gap manifold in accordance with claim 1,
   characterized in that
   the shells (2a, 3a, 4a) of the interior part (1) each forming one part of the exhaust gas guides (2, 3, 4) are first plugged into one another in accordance with the desired sliding fit arrangement, then likewise the shells (2b, 3b, 4b) each forming the other part of the exhaust gas guides (2, 3, 4); and in that only then are the associated shells (2a, 2b, 3a, 3b, 4a, 4b) of the exhaust gas guides (2, 3, 4) jointly connected to one another in that they are reshaped, in particular folded, at the rim in pairs.
9. A method in accordance with claim 8, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part (1) are latched to one another by individual spot welds; and/or in that the shells (5a, 5b) of the exterior part (5) are welded to one another in a gas-tight manner.
10. A method in accordance with claim 8 or claim 9, characterized in that the shells (2a, 2b, 3a, 3b, 4a, 4b) of the interior part (1) and/or the shells (5a, 5b) of the exterior part (5) are manufactured from sheet metal; and/or are provided with beads.

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