EP1206631B1 - Exhaust gas manifold - Google Patents

Abstract

An exhaust gas manifold for mounting on a cylinder head of an internal combustion engine, composed of at least one cylinder support having bores for evacuating the exhaust gas. The exhaust gas manifold comprises an exhaust gas manifold collector housing (9) for collecting exhaust gas from the cylinder head, and a sealing device (10) placed between the exhaust gas collector housing (9) and the cylinder head (2). The exhaust gas manifold collector housing (9) is provided with recesses (12) so that it can be directly connected to the cylinder head (2) via a fixation mechanism (18), whereby the effect of heat enables movements between the exhaust gas manifold collector housing (9) and the cylinder head (2).

Description

The invention relates to an exhaust manifold for attachment to a cylinder head of an internal combustion engine.

In EP 0 709 557 A1 an exhaust manifold is in one Execution described, as on very many internal combustion engines is used. Each exhaust pipe is with a Flange welded, which then to the cylinder head of the internal combustion engine is screwed on. The exhaust pipes open into known manner in a manifold, which is in a Exhaust pipe continues.

Disadvantageously, such known exhaust manifolds are very heavy and expensive and have the further disadvantage that they greatly affect the exhaust gas introduced by their large mass Remove heat. This reduces the temperature of the exhaust gas, which causes that in the exhaust pipe arranged catalyst in particular when starting the internal combustion engine has a very poor efficiency.

To the efficiency and the light-off behavior of the catalyst were improved according to one known from practice Prior art so-called air gap insulated exhaust manifold developed, in which a housing and an in the housing arranged gas guide line are provided.

Again, however, is still the relatively high Mass and in particular the high cost of welding during assembly of the inner gas guide line surrounding Housing and when attaching this housing to a Zylinderkopfflansch disadvantageous because both to increase the price contributes to such exhaust manifold. Due to the necessary Tightness of the exhaust manifold can in the known constructions However, such welding work is not waived become.

To counter this problem is, for example EP 0 671 551 A1 an exhaust manifold known in which a gas guide channel disposed within a housing is. In this known solution, however, the leaks Tilting weld between the outer shell the exhaust manifold and one connected to the cylinder head Flange part as well as the direct contact of the inner tube. With the cylinder head disadvantageous.

EP 0 765 994 A1 describes an exhaust manifold for a Internal combustion engine, arranged in the housing baffles are to the exhaust gas flowing into the housing in the direction to lead an outflow channel. The entire housing should thereby only one board by punching and bending are produced, wherein the baffles welded into the housing are.

US Pat. No. 4,537,027 describes an exhaust manifold in which also the exhaust gases of all exhaust bores in a common Housing be initiated.

However, in the latter two exhaust manifolds disadvantageous that due to the lack of gas duct Leakage problems emerge, making a takeover of this not to expect imaginative solutions in mass production is.

US-PS 4,214,444 shows the attachment of an exhaust manifold on a cylinder head, between which a flange an exhaust manifold housing and the cylinder head a seal is arranged. Here is a relative movement of the exhaust manifold be possible to the cylinder head.

It is an object of the present invention, an exhaust manifold for attachment to a cylinder head of an internal combustion engine to create which easily and inexpensively is, has a low mass and in easier Way attached to the cylinder head of the internal combustion engine can be.

According to the invention this object is achieved by the in claim 1 solved mentioned features.

The exhaust manifold according to the invention can directly with the cylinder head by suitable fastening means, e.g. screws get connected. To a seal between the exhaust manifold and to reach the cylinder head is merely a sealing device between the exhaust gas collecting housing and the cylinder head necessary and it can be elaborate Welding work can be dispensed with.

The exhaust manifold may advantageously be opposite expand the cylinder head and a corresponding movement Run, making elaborate constructions with sliding flanges or the like can be avoided.

A particular advantage of the exhaust manifold according to the invention is the low degree of deformation required, which makes very thin Sheets can be used with a correspondingly low mass can. This leads to very low material and manufacturing costs and that the exhaust gas is extremely low Amount of heat is withdrawn. Furthermore, the inventive Exhaust manifold has the advantage of a relative small footprint in the engine compartment of a motor vehicle on.

Because of the gas duct at its the cylinder head facing side provided with a circumferential collar is, which in the assembled state, at least indirectly between the exhaust collector housing and the sealing device is trapped, results in a very simple attachment the gas duct, but a shift of the same remains possible in the plane of the cylinder head and at the same time movements of the same perpendicular to this plane and possibly caused thereby rattling prevented become.

If in an advantageous embodiment of the invention between the exhaust manifold housing and the cylinder head Flange is arranged, so is an even better sliding movement the exhaust manifold due to possibly occurring Thermal expansion of the same relative to the cylinder head possible. In addition, this advantageously the cylinder head decoupled from the exhaust manifold.

In a further advantageous embodiment of the invention For example, a gas duct may be disposed in the exhaust manifold be. This results in an air gap insulated exhaust manifold, which due to the thin walls of the exhaust gas Gas guide channel and the air gap between the exhaust manifold and the gas guide channel relatively little Heat escapes. This prevents a sinking of the exhaust gas temperature and leads to a better starting behavior and efficiency one in the subsequent to the exhaust manifold Exhaust pipe arranged catalyst.

Furthermore, when using a gas guide channel advantageously a cost-effective and easily reshaping Structural steel used existing exhaust manifold be, since this is thermally less stressed.

Also in this embodiment, a flange between the Be arranged exhaust manifold and the cylinder head, the a better sliding movement of the exhaust gas header opposite the cylinder head allowed.

In all embodiments, results in a lower Forming degree, which is advantageously to thin sheets and thus leads to very low masses of the individual components.

Further advantageous embodiments and further developments of Invention will become apparent from the remaining dependent claims and in principle from the following with reference to the drawing illustrated embodiment.

Fig. 1

eine stark schematisierte Brennkraftmaschine mit einem daran angebrachten Abgaskrümmer;

Fig. 2

den Abgaskrümmer aus Fig. 1 in einer ersten Ausführungsform in einer Explosionsdarstellung;

Fig. 3

einen Schnitt nach der Linie III-III aus Fig. 2;

Fig. 4

den Abgaskrümmer aus Fig. 1 in einer zweiten Ausführungsform in einer Explosionsdarstellung;

Fig. 5

einen Schnitt nach der Linie V-V aus Fig. 4;

Fig. 6

den Abgaskrümmer aus Fig. 1 in einer dritten Ausführungsform in einer Explosionsdarstellung;

Fig. 7

einen Schnitt nach der Linie VII-VII aus Fig. 6;

Fig. 8

den Abgaskrümmer aus Fig. 1 in einer vierten Ausführungsform in einer Explosionsdarstellung;

Fig. 9

einen Schnitt nach der Linie IX-IX aus Fig. 8;

Fig. 10

den Abgaskrümmer aus Fig. 1 in einer fünften Ausführungsform in einer Explosionsdarstellung;

Fig. 11

einen Schnitt nach der Linie XI-XI aus Fig. 10;.

Fig. 12

eine Schnittdarstellung des Abgaskrümmers aus Fig. 1 in einer sechsten Ausführungsform; und

Fig. 13

eine Schnittdarstellung des Abgaskrümmers aus Fig. 1 in einer siebten Ausführungsform.

It shows:

Fig. 1

a highly schematic internal combustion engine with an attached exhaust manifold;

Fig. 2

the exhaust manifold of Figure 1 in a first embodiment in an exploded view.

Fig. 3

a section along the line III-III of Fig. 2;

Fig. 4

the exhaust manifold of Figure 1 in a second embodiment in an exploded view.

Fig. 5

a section along the line VV of Fig. 4;

Fig. 6

the exhaust manifold of Figure 1 in a third embodiment in an exploded view.

Fig. 7

a section along the line VII-VII of Fig. 6;

Fig. 8

the exhaust manifold of Figure 1 in a fourth embodiment in an exploded view.

Fig. 9

a section along the line IX-IX of Fig. 8;

Fig. 10

the exhaust manifold of Figure 1 in a fifth embodiment in an exploded view.

Fig. 11

a section along the line XI-XI of Fig. 10 ;.

Fig. 12

a sectional view of the exhaust manifold of Figure 1 in a sixth embodiment. and

Fig. 13

a sectional view of the exhaust manifold of Fig. 1 in a seventh embodiment.

Fig. 1 shows an exhaust manifold 1, which on a cylinder head 2 of an internal combustion engine 3 is mounted. In the present embodiment is an internal combustion engine 3 in series construction, in which the cylinder head 2 only one cylinder bank 4 with four in this case Cylinders 5 has. For internal combustion engines 3 in V-construction could of course several cylinder banks 4th be provided, in which then each of the exhaust manifold. 1 would be appropriate. In the cylinder head 2 are several, from the cylinders 5 outgoing exhaust bores 6, which in the exhaust manifold 1 open, whereby the exhaust gas in the exhaust manifold 1 arrives. The exhaust manifold 1 is at its the Internal combustion engine 3 side facing away with an opening. 7 provided, which are located at any point can and in which in known manner, an exhaust pipe. 8 is used. In the exhaust pipe 8 can not are shown catalyst used to clean the Exhaust gases used.

In FIGS. 2 to 6, the exhaust manifold 1 is in each case in various embodiments by exploded views shown.

The exhaust manifold 1 according to FIG. 2 consists of an exhaust gas collecting housing 9, which the exhaust gases from all exhaust bores 6 a cylinder bank 4 receives, and a sealing device 10. The exhaust gases, the exhaust manifold 9 through the opening 7, which faces away from the cylinder head 2 Side of it, left again and so on get into the exhaust pipe 8. The exhaust manifold 9 is surrounded at its entire circumference by a collar 11, in which recesses 12 for the implementation of in Fig. 2 fastening means, not shown, e.g. screws are located. With the fasteners is the exhaust manifold 9 attached to the cylinder head 2.

The sealing device 10 corresponds in shape to the Cylinder head 2 facing side of the exhaust manifold 9, runs over the entire area between the exhaust manifold 9 and the cylinder head 2 and has accordingly also a collar 13 with recesses 14, whose positions with the positions of the recesses 12 in the collar 11th of the exhaust manifold 9 at least approximately match.

Furthermore, the sealing device 10 has a plurality of bores 15, their number and their positions with the positions the exhaust bores 6 in the cylinder head 2 at least approximately agree to the flow of the exhaust gas from the exhaust gas holes 6 in the exhaust manifold 9 to ensure. At its the exhaust manifold 9 facing Side is the sealing device 10 with beads or stampings 16 provided which a gap between generate the cylinder head 2 and the sealing device 10. The sealing device 10 may for example consist of a be formed metallic material.

Furthermore, Fig. 2 can be removed that the exhaust manifold 9 has on its outside a bead 17. This bead 17 limits the collar 11 of the exhaust manifold 9 outwardly and increases the strength of the exhaust manifold housing 9. In the present embodiment the exhaust manifold 9 of a high temperature resistant Material and is capable of facing the sealing device 10 and thus with respect to the cylinder head 2 to perform minor movements, which by the heat input the exhaust gas and the associated expansion the exhaust manifold 9 are caused.

It would also be possible, the exhaust manifold 9 made of multilayer To produce sheets in sandwich construction, whereby the Sound radiation could be reduced. In such a Sandwich construction could for example be a layer of Steel and the other layer of aluminum, where also the production of high-temperature resistant exhaust gas collection housings 9 would be possible.

To achieve exhaust gas purification in a simple manner to be in the exhaust manifold 9 several individual Catalyst elements 39 arranged. Each catalyst element 39 is assigned to an exhaust gas bore 6 or a cylinder 5, so that in all embodiments four catalyst elements 39 are provided. For example, from known winding plate existing catalyst elements 39 are cylindrical and can be upright or be arranged horizontally. In the exhaust manifold 9 the catalyst elements 39 by not shown Drahtgestrickelemente held. Alternatively, it goes without saying also the use of a usual catalyst in the exhaust pipe 8 possible, as already mentioned above.

In Fig. 3, the above-mentioned, designed as screws 18 Fastening means for attaching the exhaust collector housing 9 shown on the cylinder head 2. These are through the recesses 12 in the exhaust manifold 9 and the recesses 14 performed in the sealing device 10. By a corresponding tightening of the screws 18, the Abovementioned displaceability of the exhaust gas collecting housing 9 can be adjusted relative to the cylinder head 2. Here is However, in each case ensures a tightness of the exhaust manifold 1. Furthermore, it can be seen that the holes 15 of the sealing device 10 is provided with Umbördelungen 19 are that extend into the exhaust bores 6 of the cylinder head 2.

4 shows a further embodiment of the exhaust manifold 1, in which in turn the exhaust manifold 9 and the Sealing device 10, but in addition a flange 20th and a further sealing device 10a are provided, to form the exhaust manifold 1. In the illustration according to 4, only the sealing device 10a can be seen. The flange 20 is provided with holes 21, the number and positions with the positions of the exhaust holes 6 in the cylinder head 2 at least approximately match. The holes 21 are formed in this case round. Of further, the flange 20 has a circumferential collar 22 and a flange 23, wherein in the collar 22 recesses 24 are introduced whose positions with the positions of Recesses 12 in the exhaust manifold 9 match.

The sealing device 10a has no in this case Exhaust bores 6 corresponding holes 15, but a over almost the entire length and almost the entire Width of the sealing device 10a extending recess 25. As in FIG. 2, the sealing device 10a but again provided with a collar 13a and recesses 14a. Due to the large recess 25, the seal is done only through the collar 13a of the sealing device 10a.

In Fig. 5 is the attachment of the exhaust manifold 1 in section shown on the cylinder head 2. Here it can be seen that the sealing device 10a between the flange 20 and the Exhaust manifold 9 is arranged. Between the cylinder head 2 and the exhaust manifold 9 is the other Sealing device 10, however, in contrast to FIG. 2 and FIG. 3 without stampings 16 and without flanges 17 is executed. From this figure also shows that the Inner contour of the bead 23 of the flange 20 with the outer contour of the exhaust manifold 9 surrounding federal 11th coincides, so that the exhaust gas collecting 9 within the Beading 23 of the flange 20 takes place. The exhaust manifold 9, however, has no flanging in this case 17 on. By stamping or spot welding For example, the exhaust gas collecting housing 9 can be preassembled with the flange 20 become.

Again, caused by heat in turn Movements between the exhaust manifold 9 and the flange 20 possible, and because of the attached between the same Sealing device 10a. As before, by the Recesses 12 in the exhaust manifold 9, the recesses 24 in the flange 20 and the recesses 14 and 14a in the sealing means 10 and 10 a, the fastening means 18 for attaching the exhaust manifold 1 to the cylinder head. 2 carried out.

Fig. 6 shows a further embodiment of the exhaust manifold 1, which in turn the exhaust manifold 9 and the sealing device 10 has. In the exhaust manifold 9 However, a gas guide channel 26 is arranged, which is in two parts formed with a bottom part 27 and a cover part 28 is. The exhaust manifold 9 is as previously with the Covenant 11 and the recesses 12 therein the collar 11 surrounding bead 17 provided. The Sealing device 10 also has as described above the collar 13, the recesses 14 and the holes 15.

The bottom part 27 of a high-temperature resistant Material produced gas guide channel 26 is provided with holes 29 provided whose positions at least approximately the positions of the exhaust bores 6 of the cylinder head. 2 to match. In this way, the exhaust gas in enter the gas guide channel 26. Within the gas guide channel 26 baffles 30 are arranged, which the gas flow from the holes 29 to one to the exhaust pipe. 8 leading opening 31, which is in the lid part 28 of the gas guide channel 26 is located. The baffles 30 can either with the exhaust manifold 9 or the gas guide channel 26 welded, or from the material of the Bottom part 27 and / or the cover part 28 of the gas guide channel 26 be embossed. When mounting the exhaust manifold 1 are mounted on on the outside of the lid part 28 Notches 32 headband 33 is placed, which for a Attachment of the gas guide channel 26 provide. With others Words, the headband 33 are arranged such that at Attachment of the exhaust gas collecting housing 9 to the cylinder head 2 by means of the fastening means 18, the headband 33, the gas guide channel 26 hold. The tightness of the gas guide channel 26 is ensured by the fact that the bottom part of the 27th very precisely matches with the cover part 28 and this two parts applied by means of the headband 33 Close the force tightly together. In addition will still the bottom part 27 embossed with the cover part 28 or Spot-welded, so that a complete pre-assembly possible is.

The formed as a resilient or damping elements headband 33 may be made of a high temperature resistant material, for example, from a high temperature resistant Knitted wire. Through this type of assembly can dispensed with elaborate welding.

In the gas guide channel 26 can also the above-mentioned Arranged catalyst elements 39 for exhaust gas purification and with wire knitting elements, not shown be held in the same.

Alternatively to the illustrated embodiment, the gas guide channel 26 also from one for fluids, in this case for Exhaust gases, permeable material exist. This can be, for example solved by a fabric or by a perforated plate be. As a result, the mass of the gas guide channel 26 is still further reduced and this can so the exhaust less heat revoke. Also in this embodiment, the exhaust gas nevertheless strive to flow in the direction of the opening 31 and only a very small part is through the gas guide channel 26 to reach the exhaust manifold 9.

In Fig. 7 it can be seen that between the gas guide channel 26 and the exhaust manifold 9, an air gap 34 is formed, which the exhaust gas flowing into the gas guide channel 26 isolated from the exhaust manifold 9. This will be the Exhaust manifold 9 heats only slightly and withdraws thus the exhaust gas relatively little heat, which leads that in the exhaust pipe 8 located catalyst due to the higher exhaust gas temperatures a better light-off behavior and has a better efficiency. Furthermore, thereby the exhaust manifold 9 from a inexpensive structural steel, possibly also from one aluminized steel can be made as it usually does not come into contact with the exhaust gas. Between the exhaust manifold 9 and the cylinder head 2 is the sealing device 10 attached.

The air gap 34 can in all versions, in which It also occurs with sound insulating materials, such as e.g. Rock wool, ceramic wool, knitted wire or individual, be filled with each other pressed wire pieces to to achieve a corresponding sound insulation.

Fig. 8 shows an embodiment of the exhaust manifold 1, which with the embodiment of FIG. 6 approximately coincident. In contrast, in Fig. 8 below the bottom part 27 of the gas guide channel 26 of the flange 20 is provided, which is very similar to the flange 20 of FIG. 4 is trained. However, the holes 21 are in the same oval shaped, i. the diameter of the holes 21st in the longitudinal direction of the flange 20 is larger than the diameter the holes 21 in the transverse direction of the flange 20. This allows a displacement or expansion movement the gas guide channel 26 within the holes 21 due of thermal expansion caused by the exhaust gas temperatures. Due to the placement of the exhaust manifold 9 in the flange 20 analogous to FIG. 4, the exhaust gas collection housing 9 not provided with the bead 17, but has only the covenant 11 on.

In Fig. 9 it can be seen that between the flange 20 and the Exhaust manifold 9, in turn, the sealing device 10a and between the exhaust gas collecting housing 9 and the cylinder head 2 the sealing device 10 is used. Here too are the headband 33 and the baffles 30 as in accordance with Fig. 6 and Fig. 7 are provided.

In Fig. 10, a further exhaust manifold 1 is shown, the very similar to the exhaust manifold 1 shown in FIG is trained. Again, the gas guide channel 26 is provided which, however, consists of several individual channels 35 exists, which in each case with connections 36 to the holes 21 formed in the flange 20 also provided here are. The holes 21 have a round cross-section and the terminals 36 are inserted into these holes 21 and optionally welded. Alternatively, there would be others Shapes of the holes 21 are possible, e.g. oval or rectangular, then the connections 36 to these forms of holes 21 would be adapted and in addition a corresponding Sealing would be done.

At their junctions, the individual channels 35 are interconnected through at each one of the ends of the individual channels 35 intended widenings in which the next single channel 35 inserted and optionally welded, connected. In the exhaust manifold 9 are retaining rings 37, which bear against the same and the gas guide channel 26th surround. By the e.g. made of a knitted wire Retaining rings 37 are vibrations of the gas guide channel 26th prevented.

From one of the individual channels 35, an output 38 passes through the Opening 7 in the exhaust gas collecting 9 to the exhaust pipe 8, which is also attached to the exhaust manifold 9 here.

In the section of FIG. 11 it can be seen that also here the sealing device 10a between the exhaust gas collecting housing 9 and the flange 20 and the sealing device 10 between the flange 20 and the cylinder head 2 are used. Furthermore, as in the embodiments according to the figures 6, 7, 8 and 9, the air gap 34 between the gas guide channel 26 and the exhaust manifold 9. Also, this gas duct 26 may be one for exhaust gases permeable and high temperature resistant material.

Fig. 12 shows another exhaust manifold 1, which also has a gas guide channel 26 in its interior. Of the Gas guide channel 26 is facing at its the cylinder head 2 Side provided with a circumferential collar 40, which between the sealing device 10 on its underside and an additional clamping element 41 on its upper side is arranged. The clamping element 41 overlaps the collar 40 partially and covers the same on its entire circumference. In order to achieve a tightness of the exhaust manifold 1, is the clamping element 41 at its the exhaust gas collecting 9th facing side provided with a circumferential sealing pad 42.

Of course, the fastening means 18 are also here provided and clamp with the help of the clamping element 41 the Gas guide channel 26 with the desired force between the Exhaust manifold 9 and the sealing device 10 and the cylinder head 2. By the above construction is a movement the gas guide channel 26 perpendicular to the cylinder head plane 2 prevents, with appropriate tightening the However, screws 18 are still one due to heat triggered movement of the gas guide channel 26 in the Level of the cylinder head 2 possible.

Also in the exhaust manifold of FIG. 13, the gas guide channel 26 provided with a circumferential collar 40. This is however, directly between the exhaust manifold 9 and the in This case also provided flange 20 again by means the fastener or screws 18 pinched. In addition, at the periphery of the collar 40 is a circumferential sealing device 43, and also between the exhaust manifold 9 and the flange 20. By at the Sealing device 43 in the direction of the cylinder head. 2 above surveys 44 and / or by a corresponding Selection of the thickness of the sealing device 43 and the like Tightening the screws 18 is also a movement here the gas guide channel 26 in the plane of the cylinder head 2 possible, while at the same time unwanted vibrations can be prevented.

Claims (20)

1. Exhaust-gas manifold (1) for mounting on a cylinder head (2) of an internal combustion engine (3), which cylinder head has at least one cylinder bank (4) provided with exhaust-gas bores (6) for the discharge of exhaust gas, said exhaust-gas manifold having an exhaust-gas collector housing (9) for receiving exhaust gas from the cylinder head (2), with a sealing device (10) arranged between the exhaust-gas collector housing (9) and the cylinder head (2); wherein said exhaust-gas collector housing (9) is provided with clearances (12) by means of which it can be connected directly to the cylinder head (2) via fastening means (18); wherein the sealing device (10) is constructed as a separate part; wherein movements brought about by the effect of heat are possible between the exhaust-gas collector housing (9) and the sealing device (10) and also between the exhaust-gas collector housing (9) and the cylinder head (2); wherein a gas-conveying duct (26) is arranged inside the exhaust-gas collector housing (9); wherein an air gap (34) is located between the exhaust-gas collector housing (9) and the gas-conveying duct (26); and wherein the gas-conveying duct (26) is provided, on its side that faces towards the cylinder head (2), with a circumferential collar (40) which, in the assembled condition, is clamped in, at least indirectly, between the exhaust-gas collector housing (9) and the sealing device (10), movements brought about by the effect of heat being possible between the gas-conveying duct (26) and the sealing device (10).
2. Exhaust-gas manifold according to claim 1,
   characterised in that the sealing device (10) extends over the entire region between the exhaust-gas collector housing (9) and the cylinder head (2).
3. Exhaust-gas manifold according to claim 1 or 2,
   characterised in that the sealing device (10) has clearances (14) whose positions at least approximately coincide with the positions of the clearances (12) in the exhaust-gas collector housing (9) for receiving the fastening means (18) for connecting said exhaust-gas collector housing (9) to the cylinder head (2).
4. Exhaust-gas manifold according to one of claims 1 to 3,
   characterised in that there is arranged, between the exhaust-gas collector housing (9) and the cylinder head (2), a flange (20) which has clearances (24) whose positions at least approximately coincide with the positions of the clearances (12) in the exhaust-gas collector housing (9) for receiving the fastening means (18) for connecting said exhaust-gas collector housing (9) to the cylinder head (2).
5. Exhaust-gas manifold according to claim 4,
   characterised in that the sealing device (10) is arranged between the flange (20) and the cylinder head (2).
6. Exhaust-gas manifold according to one of claims 4 or 5,
   characterised in that a sealing device (10a) is arranged between the exhaust-gas collector housing (9) and the flange (20).
7. Exhaust-gas manifold according to one of claims 4 to 6,
   characterised in that the flange (20) has, on its outer side, a bead (23) whose inner contour at least approximately coincides with the outer contour of the collar (11) surrounding the exhaust-gas collector housing (9), movements brought about by the effect of heat being possible between the exhaust-gas collector housing (9) and the flange (20).
8. Exhaust-gas manifold according to one of claims 1 to 7,
   characterised in that the air gap (34) is filled up with sound-absorbing materials.
9. Exhaust-gas manifold according to one of claims 1 to 8,
   characterised in that the gas-conveying duct (26) consists of a material which is permeable to fluids.
10. Exhaust-gas manifold according to one of claims 1 to 9,
    characterised in that the gas-conveying duct (26) is of two-part construction with a bottom part (27) and a cover part (28), the bores (29) being located in said bottom part (27).
11. Exhaust-gas manifold according to one of claims 1 to 10,
    characterised in that retaining clips (33) are arranged between the exhaust-gas collector housing (9) and the gas-conveying duct (26) in such a way that, when said exhaust-gas collector housing (9) is mounted on the cylinder head (2) by means of the fastening means (18), the retaining clips (33) secure the gas-conveying duct (26).
12. Exhaust-gas manifold according to one of claims 1 to 9,
    characterised in that the gas-conveying duct (26) is built up from a number of individual ducts (35) which each have connections (36) to the exhaust-gas bores (6) in the cylinder head (2).
13. Exhaust-gas manifold according to one of claims 1 to 12,
    characterised in that the circumferential collar (40) is clamped in between the sealing device (10) and a clamping element (41) which is provided with a circumferential sealing layer (42), a flange (20) being arranged between the gas-conveying duct (26) and the cylinder head (2), and the circumferential collar (40) of the gas-conveying duct (26) being arranged displaceably between the exhaust-gas collector housing (9) and the flange (20).
14. Exhaust-gas manifold according to claim 13,
    characterised in that a sealing device (43) is arranged between the circumferential collar (40) of the gas-conveying duct (26) and the flange (20).
15. Exhaust-gas manifold according to claims 12 and 13,
    characterised in that the individual ducts (35) are inserted in, and optionally welded into, the bores (21) in the flange (20).
16. Exhaust-gas manifold according to one of claims 13 to 15,
    characterised in that the flange (20) consists of a material which is resistant to high temperatures.
17. Exhaust-gas manifold according to one of claims 13 to 16,
    characterised in that the flange (20) is provided with bores (29) whose positions at least approximately coincide with the positions of the exhaust-gas bores (6) in the cylinder head (2), the diameters of the bores (29) in the flange (20) being larger, in the longitudinal direction of said flange (20), than the diameter of the bores (29) in the transverse direction of said flange (20).
18. Exhaust-gas manifold according to one of claims 1 to 17,
    characterised in that there are arranged in the exhaust-gas collector housing (9) or in the gas-conveying duct (26) metal baffle plates (30) which are welded to said exhaust-gas collector housing (9) or to said gas-conveying duct (26).
19. Exhaust-gas manifold according to one of claims 1 to 18,
    characterised in that a number of individual catalytic-converter elements (39) are arranged in the exhaust-gas collector housing (9).
20. Exhaust-gas manifold according to one of claims 1 to 18,
    characterised in that a number of individual catalytic-converter elements (39) are arranged in the gas-conveying duct (26).

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