EP0735251B1 - Exhaust collector for an internal combustion engine - Google Patents

Description

The invention relates to an exhaust manifold for an internal combustion engine, the specified in the preamble of claim 1 Genus.

EP 0 582 985 A1 describes an exhaust manifold for exhaust gas routing known from an internal combustion engine, which from a multi-part inner shell and one surrounding it at a distance Outer shell and flange means for connecting the Inner tube to several spaced cylinder outlet channels the internal combustion engine. Furthermore, for Connection of an exhaust pipe an output flange is provided, which is attached to the inner shell. The outer shell is there from shell parts that are together at their edges are connected and encloses the inner shell at its in the flange means guided ends. That way a space is formed between the inner shell and the outer shell, which are used for air gap insulation or with a Insulating material can be filled.

In the known arrangement, the flange means are for everyone Connections of the inner shell to the cylinder head in the form of a continuous flange plate as a so-called composite flange trained who in relation to the essential thinner sheet thicknesses of the inner shell and the outer shell is dimensionally stable and inelastic. Therefore, the connection areas of the individual sections of the inner shell as Sliding seat designed to be different strong strains caused by temperature changes can be compensated. To seal such Sliding seat connections are additional sealing elements provided that the exhaust gas emerges from the inner shell in the space between the outer shell and the inner shell prevented. Such an arrangement is complicated under construction, expensive to manufacture and also due to of the composite flange has a high weight.

DE-GM 80 04 882 describes an exhaust manifold which has four individual flanges in a row, the two middle individual flanges with a first Inner tube and the two outer individual flanges with one second inner tube are connected. Each of these inner tubes has an outer shell, these outer shells made of two each connected at their edges Shell parts are composed and the respective Inner tube at its ends led into the flange means enclose. There is a between the inner tube and the outer shell Space to form air gap insulation.

In the known arrangement, individual flanges are provided, due to the double arrangement of connecting pipes and outer shells, the exhaust manifold is elaborately designed and because of the much longer seams between the Outer shells are expensive to manufacture.

The invention has for its object an exhaust manifold the genus mentioned in the preamble of claim 1 to develop such that a simple structure, a reduction of the total weight and a long service life becomes.

This task is accomplished by an exhaust manifold with the features of claim 1 solved.

The advantages of the exhaust manifold according to the invention are not only in the reduction in weight and lower manufacturing costs to see, but also in the longer shelf life, especially with regard to the outer shell. The latter is achieved in that due to the design the outer shell does not have tight radii and through the design of the seams between the input flanges resulting tensions are significantly lower than with the known constructions.

A preferred embodiment of the subject matter of the invention is that the straight section of the Connect outer shell seam to lateral arches, the outer Ends are connected to the inner tube. With one The forces arising as a result of thermal expansion act as a solution almost exclusively in the longitudinal direction of the flange plane, see above that there is no significant bending stress during temperature changes occurs. Alternatively, the exhaust manifold be designed so that the arc of the outer shell seam a middle section and adjoining it laterally Sections includes, the radius of curvature of the middle Section is greater than the radius of curvature of the lateral Sections. The radius of curvature of the middle Section about five times the radius of curvature of the side sections. Another variant with regard to the contour of the seam of the outer shell in that the arch has a one between its ends has uniform curvature. The radius of the Arc preferably about 0.6 times the distance between the ends of the bow. With such a design become sections running transversely to the flange plane the seam avoided, so that the bending stress of the outer shell is kept low.

The outer shell is expediently composed of two half-shells formed, which have several seams, of which the between larger seams at the entrance flanges Have a distance to the inner tube than the other seams. This creates a box construction through which in the areas adjacent to the inlet flanges there is a greater distance between the inner tube and the outer shell results. The outer shell preferably has one between the input flanges and orthogonal roughly the shape of a Drop on.

To assemble the half shells to form the outer shell, are different types of seam design conceivable. Designs as are particularly advantageous Tucked seam or viewed as a flared seam, although it is Different seams of the outer shell can be useful to design differently. As a particularly suitable version is considered that between the input flanges run seams as a pin seam and the remaining seams are designed as flanged seams. For the flared seam are Flanged edges are provided, the width of which for mutual contact is preferably about 1 mm. A wider width is possible, but not absolutely necessary. Another Embodiment is that the flanged one Half-shell is made wider than the flange edge the other half shell, with the protrusion of the wider one Flanged edge is preferably 1 mm to 1.5 mm. This The shape of the flanged edges is especially for certain connection methods, for example laser welding to draw. The pin seam is overlapping Formed edges, the overlap portions preferably is about 4 mm. All seams of the outer shell are welded. To ensure that the air gap between the inner tube and the outer shell a predetermined distance is not less, is between the inner tube and the outer shell at least one spacer, preferably a spacer ring made from a residue that burns without residue when heated Material, provided.

Fig. 1

eine Draufsicht auf einen luftspaltisolierten Abgaskrümmer, teilweise im Schnitt,

Fig. 2

einen Schnitt entlang der Linie II - II in Fig. 1,

Fig. 3

eine vergrößerte Darstellung der Einzelheit III in Fig. 2,

Fig. 4

eine vergrößerte Darstellung der Einzelheit IV in Fig. 2,

Fig. 5

eine Ausführungsvariante zu Fig. 1,

Fig. 6

einen Schnitt entlang der Linie VI - VI in Fig. 5,

Fig. 7

eine Ausführungsvariante zu Fig. 6,

Fig. 8

eine vergrößerte Darstellung der Einzelheit VIII in Fig. 7,

Fig. 9

eine weitere Ausführungsvariante zu Fig. 1.

Embodiments of the invention are explained below with reference to the drawing. The drawing shows:

Fig. 1

3 shows a plan view of an air-gap-insulated exhaust manifold, partly in section,

Fig. 2

2 shows a section along the line II-II in FIG. 1,

Fig. 3

3 shows an enlarged view of detail III in FIG. 2,

Fig. 4

3 shows an enlarged illustration of the detail IV in FIG. 2,

Fig. 5

1 shows a variant of FIG. 1,

Fig. 6

4 shows a section along the line VI-VI in FIG. 5,

Fig. 7

6 shows a variant of FIG. 6,

Fig. 8

7 shows an enlarged illustration of detail VIII in FIG. 7,

Fig. 9

a further embodiment variant to FIG. 1.

1 shows a top view of an exhaust manifold 1, which essentially consists of a leading the exhaust gas Inner tube 2 and an outer shell 3 and several input flanges 10, 11, 12 and an output flange 5. The inner tube 2 comprises an arc piece 6, a T-shaped Center piece 7 and a Y-shaped connector 8, wherein each of pieces 6, 7 and 8 on one of the input flanges 10, 11, 12 connected and the connector 8 with a connecting piece 9 formed thereon in the output flange 5 is attached in the manner of a sliding seat. The Elbow piece 6 has the input flange 10 removed on it lying end a connecting portion 16 which in inserted a sleeve portion 17 of the middle piece 7 and in this against the outside of the inner tube 2, possibly with little play. Besides, one is Connection between the middle piece 7 and the connector 8 provided by a connecting section 16 ' on the middle piece 7 and a sleeve section 17 'on the connecting piece 8th.

The outer shell 3 consists of a first half shell 14 and a second half-shell 15, the edges of which at seams 18, 19, 20 and 21 lie against each other and welded together are. The first seam 18 extends between the Input flanges 10 and 11, the second seam 19 between the input flanges 11 and 12, the third seam 20 follows at a radial distance from the contour of the connector 8 between the input flange 12 and the output flange 5 and the fourth seam 21 runs at a radial distance from the inner tube 2 from the input flange 10 to the output flange 5. As can be seen from Fig. 1, the first and second lie Seam 18, 19 in a plane E near the flange plane, wherein the course of the seams 18, 19 at least over a section 38 is approximately straight and to the inlet flanges 10, 11, 12 out in an arc 13 with a large radius pass over. Form the respective outer ends 29 of the arches 13 the connection to the pieces 6, 7, 8 of the inner tube 2, where the distance between the ends 29 denotes L. is.

This results in a box shape for the outer shell 3, in which the distance between the outer shell and the inner tube 2 in the area between the seams 18, 19 and the inner tube 2 is much larger than the distance of the seams 20, 21 to Inner tube 2. The pieces 6, 7, 8 forming the inner tube 2 are in the openings of the input flanges 10, 11, 12 and of the output flange 5 added. The edges of the outer shell 3 can be welded into the openings of the flanges or directly in front of the inlet flanges on the inner tube be welded on. In this way there is a closed one Room 4 for air gap insulation.

On the inner tube 2 there are two at an axial distance arranged rings 30, 30 ', which consist of a material, which dissolves when heated accordingly. Therefor Polyethylene can be considered as a material that is residue-free burns and does not pollute the environment represents. These rings 30, 30 'serve as distance means between the inner tube 2 and the outer shell 3, so that The minimum air gap between these parts must not be undercut becomes.

Fig. 2 shows a section along the line II - II in Fig. 1, for reasons of clarity on the Representation of the inlet flange and the one introduced into it End of the bow piece was dispensed with. From Fig. 2 it can be seen that the first half-shell 14 and the second Half-shell 15 outwardly curved edges 22, 22 'and 23, 23 ', on which the half-shells 14 and 15 are mirror-symmetrical lie together. The edges 22, 23 and 22 ', 23' are welded together and due to the shape the edges, the seams 18, 21 are formed as flared seams. Likewise, the seams not shown in Fig. 2 have the outer shell 3 in the form of flared seams. The cross section the outer shell 3 has essentially the shape a drop, with the first seam 18 in one essential greater distance to the bow piece 6 than that fourth seam 21. The wrap angle over which the contour the outer shell 3 at a radially constant distance runs to the inner tube 6, is preferably approximately 230 °.

3 and 4 each show enlarged representations the connection areas of the half-shells 14 and 15, from which the contour of the edges 22, 23 or 22 ', 23' and the shape the flared seam becomes clear. It can be seen that the Width B of the flanged edges for mutual contact only needs to be small, a width B of about 1 mm is considered sufficient, but may be construction-related also run larger. Alternatively an embodiment can also be provided in which the hem of a half-shell is wider than the beaded edge of the other half-shell, the protrusion of the wider flange edge is preferably 1 mm to 1.5 mm. For connecting the half-shells 14, 15 by means of This version is particularly suitable for laser welding.

5 shows an embodiment variant of FIG. 1, at which formed the outer shell 3 from two half-shells 24 and 25 is the first seam 26 and second seam 27 in one Arc 28 of different curvature runs. Doing so the shape of a central section 35 with a large radius of curvature and laterally adjoining sections 36 formed with a slightly smaller radius, the outer End 34 of sections 36 into a weld seam at the ends the bow piece 6 of the middle piece 7 and the connecting piece 8, which in the openings of the input flanges 10, 11, 12 are passed. The ends 34 of the arch 28 are thus also arranged at a distance L from one another. This shape is the distance between the seams 26 and 27 to the inner tube 2 is not as large as in the exemplary embodiment 1, but still significantly larger than the distance between the seam 21 and the inner tube 2, as shown in the Representation in Fig. 6 emerges. Otherwise it is correct 5 corresponds to that of FIG. 1; this also applies to the reference symbols for identical parts.

6 shows a section along the line VI - VI in Fig. 5, as well as in Fig. 2 on a representation of Input flange and the inner tube section connected to it was waived. From Fig. 6 it is clear that the second seam 27 is designed as a plug seam in which an edge 31 of the first half-shell 24 and an edge 32 of the engage second half-shell 25. The fourth seam 21 corresponds in terms of its shape to that described for FIG. 2 Flanged seam. Between the inner tube 2 and the outer shell 3, the ring 30 'is arranged.

FIG. 7 shows an embodiment variant of FIG. 6, at the fourth also opposite the second seam 27 Seam 33 is designed as a seam, so that the edges the half-shells 24 and 25 interlock like a hat box. In Fig. 8 the detail VIII of Fig. 7 is shown enlarged, from which it can be seen that the overlapping edges 31 and 32 of the half-shells 24, 25 are connected to each other by a weld 37, wherein an overlap section A is formed, which is preferably is about 4 mm.

FIG. 9 shows a further embodiment variant of FIG. 1, in which the contour of the first and second seams 39 and 40 corresponds to an arc 41 of uniform curvature Ends 42 are attached to the inner tube 2. The is Radius of the arc 41 is approximately 0.6 times the distance L. between the ends 42, the seams 39, 40 or the arch 41. For the rest, this version agrees with that of FIG. 5 agree, this also applies to the reference numerals for the same Parts.

Claims (8)

1. An exhaust manifold (1) for an internal combustion engine having an inner pipe (2) and an outer shell (3) enclosing the inner pipe at a distance therefrom, and having at least two inlet flanges (10, 11, 12) which can be joined to a cylinder head arranged spaced apart from one another in order to connect the inner pipe to at least two cylinder outlet passages of the internal combustion engine spaced apart from one another as well as an outlet flange (5) joined to the inner pipe (2) to provide a connection to an exhaust gas pipe, the outer shell (3) being made up of at least two shell components joined to one another by their edges (22, 23; 31, 32) and surrounding the inner pipe (2) at the ends thereof inserted in the flange means and a chamber (4) is formed between the inner pipe (2) and the outer shell (3) to provide air-gap insulation and the outer shell (3) consists of two half-shells (13, 14) having several seams (18 to 21),
   characterised in that the seams (18, 19) run between two respectively adjacent inlet flanges, these seams (18, 19) being spaced at a greater distance from the inner pipe (2) than the other seams (20, 21) and in that the outer shell (3) is of an almost droplet shape in a plane lying between the inlet flanges (10, 11, 12) and orthogonal thereto.
2. An exhaust manifold as claimed in claim 1,
   characterised in that a seam (18, 19) of the outer shell (3) running between the inlet flanges (10, 11, 12) has a contour comprising an essentially straight section (28) which lies in a plane (E) close to and parallel with the inlet flanges (10, 11, 12).
3. An exhaust manifold as claimed in claim 1,
   characterised in that a seam (26, 27, 39, 40) of the outer shell (3) running between the inlet flanges (10, 11, 12) has a contour which runs in a curve (28, 41) having a radius of curvature at least in a section (35) that is at least approximately half the size of the distance (L) between the curve ends (34, 42).
4. An exhaust manifold as claimed in claim 2,
   characterised in that lateral curves (13) adjoin the straight section (38), the outer ends (29) thereof being joined to the inner pipe (2).
5. An exhaust manifold as claimed in claim 3,
   characterised in that the curve (28) has a middle portion (35) and sections (36) adjoining the sides thereof, the radius of curvature of the middle section (35) being greater than the radius of curvature of the side sections (36).
6. An exhaust manifold as claimed in claim 5,
   characterised in that the radius of curvature of the middle section (35) is approximately five times the radius of curvature of the side sections (36).
7. An exhaust manifold as claimed in claim 3,
   characterised in that the curve (41) has a constant curvature between its ends (42).
8. An exhaust manifold as claimed in claim 7,
   characterised in that the radius of the curve (41) is approximately 0.6 times the distance (L) between the ends (42) of the curve (41).

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