EP0731258B1 - Exhaust manifold - Google Patents

Abstract

The assembly consists of a flange (1) on which outlet pipes (4) are mounted. At least two of the pipes (4) are shaped so that they have semi-circular cross section and can together be mounted in a larger tube (6) of circular cross section. This larger tube and a third outlet pipe (4) are shaped so that they can be joined and mounted in a large outlet pipe (7). The outlet pipe is connected to the same flange (1) to which the outlet pipes (4) are connected, or to a separate flange. The outlet pipe of the engine is connected to this flanges (1). The whole assembly is enclosed in a cover (19) which is also mounted on the flange (1).

Description

The invention is based on an air-gap-insulated exhaust manifold for Internal combustion engines according to the preamble of claim 1.

It has so far been customary for such exhaust manifolds to have a manifold, the roughly speaking parallel or in the longitudinal direction of the just trained Cylinder flange runs. The coming from the cylinder flange Cylinder tubes are then in with the edges of openings connected to the manifold so that the longitudinal direction of the cylinder tubes with the longitudinal direction of the manifold a substantially right Includes angle. It is to improve the flow behavior attempts have been made to make the cylinder tubes slightly curved, so that they open diagonally into the collecting pipe.

For connection, it is possible to connect the cylinder tube to a To provide a collar that is connected to the tube by means of a weld seam becomes.

This solution has the disadvantage that a high manufacturing cost Making the holes in the pipes, fitting the collar to the Pipe and through the welds must be operated. Because the welded on Collar opposes the direction of expansion of the collecting tube, cracks also appear. Entry of gas from the cylinder barrel at an angle to the longitudinal axis causes the hot Gas acts on the opposite wall, causing it to rise there Temperatures, possibly leading to hole burnout. Moreover is created by the oblique inflow, the adversely affects the optimal gas velocity.

It is already an air gap insulated exhaust manifold with the features of the first part of claim 1 known (DE-A-42 26 171).

Furthermore, it is known that the ends of self-supporting exhaust pipes parallel to and adjacent to each other to arrange. This is to ensure that the individual Gas pulses originating from cylinder tubes at different times in lead a further exhaust pipe (WO 92-03639).

The invention has for its object one in fluidic and manufacturing technology improved exhaust manifold create.

To achieve this object, the invention proposes a manifold with features mentioned in claim 1. Developments of the invention are the subject of subclaims.

The invention therefore proposes that in a case with three cylinder tubes it is provided that the first two cylinder tubes are brought together in parallel are and with an axially aligned intermediate header get connected. This intermediate header pipe can then be used the third cylinder tube in turn aligned and merged then a connection, for example by plugging in, with the header pipe running in the same direction. In this case, when the intermediate manifold is brought together with the third cylinder tube the intermediate manifold a double as large a cross section as the cylinder tube since it is the gas flow from two cylinder tubes.

Similarly, when four or more are merged Cylinder tubes are proceeded.

In the constellation mentioned above, where the longitudinal direction of the Manifold transverse to the directions of those attached to the cylinder flange The first two cylinder tubes are like this shaped so that in its end region the direction of the intermediate header exhibit. This curvature, for example by 90 °, can be so take place that a gradual deflection of the gas jet is effected. In its end area, that is, when the gas flows into the intermediate manifold, the gases are already in the same direction as the intermediate manifold, so that there are no one-sided local impacts on wall parts. The making of holes in the wall of the intermediate header omitted, since the first two cylinder tubes axially in there anyway Opened intermediate header pipe inserted or connected to it become.

Because the gas flows when exiting the first two cylinder tubes and already parallel to each other when entering the intermediate header the problem of mutual disability also arises the gas flows no longer. This leads to an improvement in the engine characteristics. Cross-sectional selection can ensure that that the flow rate of the two gas flows when leaving the cylinder tubes are the same. The same applies to the third and possible further cylinder tubes.

In a development of the invention it can be provided that the one another adjacent merged ends of the cylinder tubes along one especially abut a flat surface.

The invention proposes that the cross section through the merged Ends of the first two cylinder tubes each with a semicircle, can correspond to a semi-oval or another semi-shape. If for example, the intermediate header pipe has a circular cross section has, contain the first two cylinder tubes in their end region a semicircular cross section. With an oval intermediate header pipe the cross section would accordingly have the shape of a have half oval.

According to the invention it can be provided that the intermediate header pipes secured against slipping by lugs, bulges or projections be, these are arranged so that temperature expansions are still possible.

The proposed parallel alignment of the merged by the invention End of cylinder tubes is especially in the case of air gap insulated Exhaust manifolds applicable in which the gas-bearing inner pipe system is arranged within an outer shell, which with the cylinder flange and connected to the collecting flange, in particular welded is. In this case, the connection between the cylinder tubes, the manifold and the intermediate manifolds by simple Plug in because gas tightness is no longer required. By appropriate shaping and tight fitting of the individual parts together, it can be ensured that the leakage is kept small becomes.

Fig. 1

eine schematische Seitenansicht eines Abgaskrümmers, bei dem der Zylinderflansch einstückig in einen Sammelflansch übergeht;

Fig. 2

Querschnitte durch die Anordnung der Fig. 1 an zwei Stellen;

Fig. 3

Querschnitte durch eine ähnliche Anordnung bei einer anderen Außenform;

Fig. 4

einen Teillängsschnitt durch einen Abgaskrümmer mit drei Zylinderrohren;

Fig. 5

einen Längsschnitt durch den Abgaskrümmer der Fig. 1.

Further features, details and advantages emerge from the patent claims, the wording of which is made by reference to the content of the description, the following description of a preferred embodiment of the invention and with reference to the drawing. Here show:

Fig. 1

is a schematic side view of an exhaust manifold, in which the cylinder flange integrally merges into a collecting flange;

Fig. 2

Cross sections through the arrangement of Figure 1 in two places.

Fig. 3

Cross sections through a similar arrangement with a different outer shape;

Fig. 4

a partial longitudinal section through an exhaust manifold with three cylinder tubes;

Fig. 5

2 shows a longitudinal section through the exhaust manifold of FIG. 1.

The exhaust manifold shown in Fig. 1 includes a flange 1 which in its left part in Fig. 1, which is about two thirds of the total length extends as a cylinder flange 2 is formed. In his mind of it right adjoining Part of the flange 1 is then designed as a collecting flange 3. Starting from the cylinder flange 2 are three cylinder tubes 4 attached to the flange, for example by welding. Each cylinder tube 4 has an opening in the cylinder flange 2 in connection so that the through the opening of the Flange 2 passing gas jet through the corresponding Cylinder tube 4 is derived.

The cylinder tubes 4 are approximately on the cylinder flange 2 attached at right angles and extend from there on over a quarter arch in one direction that essentially parallel or slightly oblique to the surface of the flange 1 runs.

The first cylinder tube, on the far left in FIG. 1, extends to beyond the second cylinder tube 4, the two first cylinder tubes 4 abut each other and in their End regions 5 run parallel to each other. Both end areas 5 of the first two cylinder tubes 4 are in an intermediate header tube 6 inserted, the axis of which is the same direction has as the end regions 5 of the cylinder tubes 4. It occurs So in the intermediate header 6 no deflection of the two the two cylinder tubes 4 emerging gas jets.

The intermediate header 6 then continues approximately straight up to the also coaxially aligned manifold 7th

The third cylinder tube 4, which also has a quarter arc is curved, is parallel in its end region to the end region of the intermediate header 6 and lies with his wall on this. It is next to the intermediate header 6 inserted horizontally into the end of the collecting tube 7, so that both the gas jet emerging from the intermediate header 6 as well as the gas jet from the cylinder tube 4 when entering run parallel to each other in the collecting tube 7. The Collecting tube 7 now picks up and directs all gas jets over the sheet 8 at its end to the as Collective flange acting part 3 of the flange.

At an exhaust manifold for an internal combustion engine is around 1 can be seen an outer shell, for example in the form of a hood, arranged around with the flange 1 is welded gas-tight.

Fig. 2 shows in its right half a section through the Arrangement of Fig. 1 along the line B-B, i.e. H. at the Point at which the end regions 5 of the two cylinder tubes 4 into the intermediate collecting tube with a circular cross-section open out. The cross section of the two end regions 5 corresponds to a semicircle, with a flat one Partition between the two walls that are close together issue. The intermediate header 6 is a close fit created around the two end regions 5. Both end areas 5 of the first two cylinder tubes 4 have the same Cross-sectional shape and the same cross-sectional size. From there the same amount of gas flows out of both cylinder tubes this way an equal speed of the two Gas flows reached when entering the intermediate header 6.

Fig. 2 shows on the left a cross section through the arrangement along the line A-A. The end region 5 opens at this point of the third cylinder tube 4 together with the end region of the Intermediate header tube 6 in the header tube 7. Again, the End region of the intermediate header tube 6 along a plane Partition surface at the end region of the third cylinder tube 4. However, the cross section of the intermediate header tube 6 is approximately twice as large as the cross section of the cylinder tube 4 since from the intermediate header 6 the gas flow from the two first cylinder tubes 4 emerges.

3 shows corresponding representations in an exhaust system, in which both the header pipe and the intermediate header pipe 6 has an oval cross section.

Fig. 4 shows a longitudinal section through part of a Arrangement on an enlarged scale. The cylinder flange 2 has a plurality of openings 10 already mentioned, from which the exhaust gases from the internal combustion engine escape. In every opening 10 is the end of a cylinder tube 4 assigned to the engine used and welded. The opposite ends 5 of the first two cylinder tubes 4 are in the intermediate header 6 inserted. The two ends 5 of the first two Cylinder tubes 4 are neither with each other nor with the intermediate header 6 welded or soldered, so that due to the Eliminating such a connection further reduced costs can be. The first cylinder tube 4 contains just before its end portion 5 has an outward projection Shape of a bead 11, for example, over a Extends part of its circumference.

At the opposite end is the intermediate header 6 together with the third cylinder tube 4 in the manifold 7 inserted. Here contains the intermediate header pipe 6 a bead 12 corresponding to the bead 11 Distance of the bead 12 from the associated end edge of the Intermediate manifold 6 is chosen so that thermal stresses can be included.

The two beads 11, 12 are intended to prevent the intermediate collecting tube from slipping off 7 for temperature changes and for Prevent vibrations.

4, the ends 5 of the range Cylinder tubes 4 or the end region of the intermediate header tube 6 a relatively short distance into the next one Component. The arrangement is chosen so that each gas-carrying pipe element inside into the following pipe element is inserted. The two merged ends 5 of the the first two cylinder tubes 4 end in the same plane, as well as the third cylinder tube 4 and the intermediate header tube 6th

Fig. 6 shows again the arrangement of Fig. 1, this time an outer shell 13 is broken off at the ends of the flange 1 is shown, along the edge of the flange 1 with this is welded. The flange 13 can also have holes 14, which have corresponding connection holes 15 of flange 1 match.

Claims (7)

1. An air gap insulated exhaust manifold having a cylinder head flange (2) for the attachment of the manifold to a cylinder head, having a manifold flange (3) for the connection of a manifold outlet pipe, having an outer shell (13), which is connected to the cylinder head flange (2) and to the manifold flange (3), and having a gas conducting inner pipe system within the outer shell (13), which has a collecting pipe (7) connected to the manifold flange (3) and at least three primary pipes (4) connected to the cylinder head flange (2), characterised in that
   the ends (5) of the first two primary pipes (4) extend parallel to one another;
   are arranged contacting one another and are connected to, in particular inserted into, an axially oriented intermediate collecting pipe (6) which, with the third primary pipe (4), is in turn arranged extending parallel to one another in the end region, and contacting one another and being joined together in the end region and connected to, in particular inserted into, the collecting pipe (7), or to a further intermediate collecting pipe.
2. An exhaust manifold in accordance with claim 1, wherein the ends (5) of the primary pipes (4) contacting one another and being led together contact one another along a surface, in particular a planar surface.
3. An exhaust manifold in accordance with claim 1 or claim 2, wherein the cross-section through the ends (5) of the two first primary pipes (4), which are led together, corresponds in each case to a semi-circle or a semi-oval.
4. An exhaust manifold in accordance with any one of the preceding claims, wherein the intermediate collecting pipes (6) are held between projections (11, 12) or bulges.
5. An exhaust manifold in accordance with any one of the preceding claims, wherein the collecting pipe (7) and/or the intermediate collecting pipes (6) have a cross-section corresponding to the common cross-section of the primary pipes (4) which are led together.
6. An exhaust manifold in accordance with any one of the preceding claims, wherein the cross-sectional partitioning of the intermediate collecting pipes (6) and/or of the collecting pipe (7) corresponds to the number of primary pipes (4) which are led together.
7. An exhaust manifold in accordance with any one of the preceding claims, wherein the primary pipes (4), the collecting pipe (7) and the intermediate collecting pipes (6) are connected to one another by insertion.

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