DE102012004954A1 - Exhaust gas manifold for use in cylinder head of e.g. V-engine, has partial exhaust gas manifold comprising one or multiple exhaust gas guiding exhaust lines that are partially formed as metal sheet component - Google Patents

Abstract

The manifold (1) has an exhaust gas inlet (2) connectable to a combustion chamber outlet of an internal combustion engine. An exhaust gas outlet (3) is arranged downstream the exhaust gas inlet. A partial exhaust gas manifold (6) is provided downstream another partial exhaust gas manifold (5), which comprises a water jacket (7). One or multiple exhaust gas guiding exhaust lines of the former partial exhaust gas manifold are partially formed as a metal sheet component. The former partial exhaust gas manifold is entirely made of the metal sheet component.

Description

The invention relates to an exhaust manifold for an internal combustion engine having at least one connectable to a combustion chamber outlet of the internal combustion engine exhaust inlet and a downstream of the exhaust gas inlet disposed exhaust gas exhaust outlet of the internal combustion engine.

Exhaust manifolds of the type mentioned are known from the prior art. They are part of the internal combustion engine or connected to it. The internal combustion engine has at least one cylinder or combustion chamber, from which exhaust gas is periodically discharged through the combustion chamber outlet. The exhaust gas passes through the exhaust gas inlet into the exhaust manifold and from there through the exhaust gas outlet of the exhaust manifold into further regions of an exhaust system associated with the internal combustion engine, which also comprises the exhaust manifold. For example, adjoins the exhaust manifold a downpipe of the exhaust system. The exhaust manifold is often present as a solid cast component. At the same time it is exposed during operation of the Brennkraffmaschine due to the large amount of heat still contained in the exhaust gas of a high temperature load. This means that high temperature castings must be used for the exhaust manifold. On the one hand, this leads to a high weight of the exhaust manifold and, on the other hand, to high costs, because such cast materials are very expensive compared to cast materials suitable only for lower temperatures.

It is therefore an object of the invention to provide an exhaust manifold, which does not have the disadvantage mentioned above, but in particular has a lower weight and is cheaper to produce than known from the prior art exhaust manifold.

This is achieved according to the invention with an exhaust manifold having the features of claim 1. It is provided that the exhaust manifold consists of at least a first partial exhaust manifold and a second partial exhaust manifold provided downstream of the first partial exhaust manifold, the first partial exhaust manifold having a water jacket and at least one exhaust-carrying exhaust pipe of the second partial exhaust manifold at least partially present as a sheet metal component. The exhaust manifold is made up of several parts. It consists of several partial exhaust manifolds, in particular the first partial exhaust manifold and the second partial exhaust manifold. In this case, the first partial exhaust manifold should have the water jacket and be coolable so far. The water jacket can be supplied with coolant via a coolant inlet and can be removed via a coolant outlet. The coolant is, for example, water. In particular, the water jacket is connected to a cooling device or a coolant circuit of the internal combustion engine. By means of the water jacket or the coolant flowing through it, the exhaust gas flowing through the exhaust manifold is cooled in the first partial exhaust manifold. The first partial exhaust manifold is designed due to the realized by means of the water jacket active cooling for high temperatures, as they are immediately downstream of the combustion chamber outlet or the exhaust gas inlet of the exhaust manifold.

Downstream of the first partial exhaust manifold, the exhaust gas enters the second partial exhaust manifold or its exhaust gas-carrying exhaust pipe. It is now provided that at least one region of the exhaust pipe is present as a sheet metal component and insofar consists of sheet metal, in particular made of sheet steel. Under sheet metal is understood to be a metal component with low wall thickness. In particular, the sheet is a thin sheet, thus has a thickness of at most 3 mm. Alternatively, stronger sheet metal can be used. Ideally, a thickness of 0.5 mm is not exceeded. Accordingly, at least the exhaust pipe of the second partial exhaust manifold is not solid, but consists of the light compared to a cast component sheet. In this way, a significant material savings and correspondingly a lower weight of the exhaust manifold is achieved. The material savings also significantly reduce costs. This is especially true if the material of the second partial exhaust manifold must be high temperature resistant for thermal reasons, because less material must be expended for the present as sheet metal component exhaust manifold than for a corresponding cast component made of high temperature resistant material.

In addition, the exhaust gas is already cooled when entering the second partial exhaust manifold or the exhaust pipe using the water jacket of the first partial exhaust manifold, so that the temperature of the exhaust gas is less than immediately downstream of the combustion chamber outlet. Accordingly, the material of the second partial exhaust manifold or the sheet metal component must be designed only for the correspondingly lower temperature. It is provided in particular that the second partial exhaust manifold is uncooled, so not also has a water jacket. Particularly preferably, the first partial exhaust manifold consists of a first material and the second partial exhaust manifold of a second material which is in the form of at least one sheet metal element. The second material is different in particular from the first material, for example, it has a higher Temperature resistance or heat resistance.

The cooling of the exhaust gas by means of the water jacket is known in principle. To reduce the temperature of the exhaust gas is cooled in known embodiments, the entire exhaust manifold using the water jacket or the exhaust gas of several exhaust strands in a cylinder head of the engine merged and the exhaust already cooled there. In the latter case, the exhaust manifold is thus integrated, for example, in the cylinder head. In this way, downstream components or the exhaust manifold itself should be protected against thermal overload in the flow direction of the exhaust gas. For both integrated and external cooled exhaust manifolds, which are cast components, the entire exhaust manifold often needs to be cooled to keep its temperature within acceptable limits. However, this means a high input of heat or heat energy into the cooling device, in particular the coolant circuit of the internal combustion engine, and / or a strong reduction of the thermal energy contained in the exhaust gas. However, the latter is usually undesirable because the energy contained in the exhaust gas is often used to operate an exhaust gas turbocharger.

The use of high temperature solid cast materials for the entire exhaust manifold allows less cooling with less heat input into the cooler and allows for the presence of higher temperatures in the exhaust manifold. However, it has, as already explained above, a massive extra weight result. The production of the entire exhaust manifold as a sheet metal component, in particular in the form of a sheet metal welding, with a water jacket, allows a weight saving, but is very expensive: The temperature of the exhaust gas is significantly higher than the temperature of the coolant in the water jacket. Accordingly, there is a very large temperature gradient in the region of the wall of the exhaust manifold. Thermal stresses in the connecting regions of the sheet metal component, ie in particular the welds, can not be excluded structurally and functionally and cause component failure of the exhaust manifold over time. Furthermore, in the case of a sheet-metal component, the water jacket can not be designed to be flow-optimized, so that the coolant is subjected to a high flow resistance. In structurally related corners and edges of the water jacket of such exhaust manifold may lead to a demolition of the flow of the coolant. This often results in a boiling of the coolant, whereby the cooling is locally almost completely interrupted. Accordingly, a component failure can also be the result here.

A development of the invention provides that the entire second partial exhaust manifold is present as a sheet metal component. It is thus provided that not only a region of the exhaust pipe consists of sheet metal, but the entire second partial exhaust manifold, in particular the entire exhaust pipe of the second partial exhaust manifold. The second partial exhaust manifold is present, for example, as a sheet-metal welding component. This means that it consists of welded together sheet metal elements. In this way, a particularly significant weight reduction of the exhaust manifold is achieved.

A development of the invention provides that the second partial exhaust manifold is fastened via a weld to the first partial exhaust manifold. As already stated above, it is at best possible with great difficulty to design the exhaust manifold completely as a sheet metal welding component. This is particularly true because welds of such a sheet metal welding component are very susceptible to thermal stresses. In particular, repeated occurrence of such thermal stresses can lead to a rupture of the weld seam and thus to a component failure of the exhaust manifold. For this reason, welds are usually avoided in exhaust manifolds. However, in the above-described configuration of the exhaust manifold consisting of the first and second partial exhaust manifolds, the weld for attaching the second partial exhaust manifold to the first partial exhaust manifold may be easily provided because the temperature of the exhaust gas has already been lowered by the water jacket. Moreover, it is particularly advantageous if the weld is coolable using the water jacket. The weld should therefore connect to the water jacket or be present on the water jacket shell. Alternatively, it can also be provided that there is only a thermal connection between the weld seam and the water jacket or its water jacket casing, for example via a thermal bridge made of a good heat-conducting material.

A development of the invention provides that the first partial exhaust manifold is present as a cast component with integrated water jacket. While exhaust manifolds known from the prior art are completely available as cast components, this is provided here only for the first partial exhaust manifold. Because the first partial exhaust manifold has the water jacket for cooling, it is not necessary to use a high temperature resistant cast material. The water jacket should be integrated into the cast component.

This means that when manufacturing the first partial exhaust manifold by casting the water jacket is formed simultaneously with. In this respect, the first partial exhaust manifold or the cast component form the water jacket envelope of the water jacket, which is designed to guide the coolant between the coolant inlet and the coolant outlet.

A development of the invention provides that the second partial exhaust manifold has an exhaust flange of the exhaust manifold receiving the exhaust gas outlet. Consequently, the exhaust gas from the combustion chamber outlet flows through the exhaust gas inlet into the first partial exhaust manifold. Subsequently, the exhaust gas from the first partial exhaust manifold enters the second partial exhaust manifold or its exhaust pipe. Subsequently, the exhaust gas flows out of the exhaust manifold through the exhaust outlet. This exhaust outlet is now formed or encompassed by an outlet flange of the exhaust manifold. In the case of the exhaust outlet or outlet flange, for example, a down pipe of the exhaust system, which comprises the exhaust manifold, connected thereto. The bifurcated tube is provided in particular in internal combustion engines with V-arrangement, which have a plurality of cylinder banks, which is assigned in each case an exhaust manifold. Through the bifurcated pipe, the exhaust gas flowing out of the exhaust manifolds is summarized below and supplied to further elements of the exhaust system, in particular a catalyst.

A further development of the invention provides that the second partial exhaust manifold has at least one receptacle for an exhaust gas sensor, which crosses through a wall of the sheet metal component. The receptacle or sensor receptacle can be formed with comparatively little effort on the second partial exhaust manifold. The exhaust gas sensor should at least partially extend into the exhaust gas. He therefore passes through the sheet or made of sheet metal wall of the second partial exhaust manifold completely in the direction of the exhaust gas.

A development of the invention provides that the second partial exhaust manifold has a lower heat capacity than the first partial exhaust manifold. This is achieved in particular by the mass of the second partial exhaust manifold is significantly lower than that of the first partial exhaust manifold. Accordingly, the second partial exhaust manifold cools much faster after stopping the internal combustion engine and thus interrupting the coolant flow through the water jacket of the first partial exhaust manifold than the first partial exhaust manifold. Thus, it can not come to a thermal overload. A possibly provided for cooling the exhaust manifold overrun pump can therefore be omitted or dimensioned considerably smaller.

A development of the invention provides that the second partial exhaust manifold consists at least of the at least one exhaust pipe and a manifold jacket surrounding the exhaust pipe. The exhaust pipe is used directly to guide the exhaust gas through the second Teilabgaskrümmer. It is so far connected to the first partial exhaust manifold or its flow-leading areas and the exhaust gas outlet of the exhaust manifold. To protect the exhaust pipe and for mechanical stabilization of the manifold shell is now provided, which surrounds the exhaust pipe at least partially, in particular completely. He is at least partially spaced from the exhaust pipe. Particularly preferably, the manifold jacket is not in direct contact with the exhaust pipe. In this way, the transfer of heat from the exhaust pipe to the manifold shell is prevented. Accordingly, the manifold shell may consist of a material which has a lower temperature resistance than the material of the exhaust pipe. The second partial exhaust manifold therefore does not have to be of uniform material. Rather, the exhaust pipe may consist of a different material from the material of the manifold shell material. Of course, however, a uniform material design may be provided.

A development of the invention provides that the exhaust pipe of the second partial exhaust manifold is flow-connected via at least one overflow opening with at least one exhaust gas duct of the first partial exhaust manifold. In the first partial exhaust manifold so there is the exhaust system, which is connected to the exhaust gas inlet of the exhaust manifold. The exhaust gas flows in this way through the exhaust gas inlet in the exhaust system. On its side facing away from the exhaust gas inlet, the exhaust gas guide is connected to the overflow opening, through which the exhaust gas can pass from the exhaust gas duct into the exhaust gas line. It can be provided that there are multiple exhaust ducts in the first partial exhaust manifold. By way of example, each combustion chamber outlet is assigned an exhaust system, wherein these exhaust systems may be present at least partially fluidly separated from one another in the first partial exhaust manifold. Of course, however, it can also be provided that at least some of the exhaust ducts or all exhaust ducts are already merged in the first partial exhaust manifold. The overflow opening represents the interface between the first partial exhaust manifold and the second partial exhaust manifold. Preferably, each exhaust gas duct is assigned an overflow opening. However, it can a fluidic overlap of at least two overflow openings may be provided.

A development of the invention provides that in the second partial exhaust manifold, there are a plurality of exhaust pipes which are brought together upstream of the outlet flange. It can thus be provided that in the first partial exhaust manifold there are a plurality of exhaust ducts, which are fluidically separated from each other in it. This means that the exhaust gas flowing through the exhaust passages is brought together only after flowing into the exhaust pipes of the second partial exhaust manifold. In any case, however, a merging of the exhaust gas upstream of the exhaust gas outlet and the Auslassflanschs is provided.

The invention further relates to an internal combustion engine with an exhaust manifold according to the above.

The invention will be explained in more detail with reference to the embodiments illustrated in the drawings, without any limitation of the invention. Showing:

1 an exhaust manifold for an internal combustion engine, and

2 an exploded view of the exhaust manifold.

The 1 shows an exhaust manifold 1 for an internal combustion engine, not shown here. The internal combustion engine has several cylinders or combustion chambers. In the present embodiment, the internal combustion engine is an internal combustion engine two cylinder banks in V-arrangement, each having a plurality of cylinders (here: three) or combustion chambers. Each of the cylinder banks is an exhaust manifold 1 assigned, the exhaust manifold 1 For example, mutually mirrored with respect to a longitudinal axis of the internal combustion engine are formed. The exhaust manifold shown here 1 In this respect, all cylinders are assigned to one of the cylinder banks of the internal combustion engine. Each cylinder has a combustion chamber outlet, to each of which an exhaust gas inlet 2 the exhaust manifold 1 fluidically connected. Through the combustion chamber outlet and the connected exhaust inlet 2 can accordingly in the operation of the internal combustion engine emerging exhaust gas from the cylinder in the exhaust manifold 1 flow. Downstream of the exhaust inlets 2 is an exhaust outlet 3 provided, through which the exhaust gas from the exhaust manifold 1 can flow out.

While the exhaust manifold 1 several exhaust gas inlets 2 it preferably has only a single exhaust gas outlet 3 , That through the multiple inlets 2 in the exhaust manifold 1 inflowing exhaust gas is corresponding upstream of the exhaust outlet 3 merged and subsequently flows together from the exhaust manifold 1 out. To the exhaust outlet 3 , which, for example, at an outlet flange 4 is present, for example, a downpipe of an exhaust system of the internal combustion engine, which is also the exhaust manifold 1 belongs, connected. By means of the bifurcated pipe that is from the exhaust manifolds 1 merging exhaust gas and other elements of the exhaust system, such as a catalyst supplied. The exhaust manifold shown here 1 is designed in several parts. He consists of a first Teilabgaskrümmer 5 and a second partial exhaust manifold 6 , The first partial exhaust manifold 5 has a water jacket 7 on, which by a water jacket cover 8th is included. The water jacket 7 is via a coolant inlet 9 Coolant supplied and removable via a coolant outlet, not shown here. The water jacket 7 is connected, for example, to a cooling device or coolant circuit of the internal combustion engine.

The first partial exhaust manifold 5 is by means of an inlet flange 10 attached to the internal combustion engine such that the exhaust gas inlets 2 in fluid communication with the combustion chamber outlets. The first partial exhaust manifold 5 exists essentially as a cast component, in which the water jacket 7 is integrated. The water jacket 7 or the water jacket casing is thus common with other areas of the first partial exhaust manifold 5 formed during its manufacture. The second partial exhaust manifold 6 has, however, a not visible here exhaust pipe 11 on, which at least partially consists of sheet metal. The exhaust pipe 11 is from a manifold jacket 12 surrounded at least partially. The second partial exhaust manifold 6 , in particular its exhaust pipe 11 and / or its manifold jacket 12 , are by welding, so over a weld 13 , on the first partial exhaust manifold 5 attached. At the exhaust manifold 1 is still a recording 14 provided for an exhaust gas sensor, not shown here. The recording 14 is on the second partial exhaust manifold 6 arranged and passes through the manifold shell 12 and also the exhaust pipe 11 such that a central passage opening 15 the recording 14 the introduction of an exhaust gas sensor in an interior of the exhaust pipe 11 , ie into the exhaust gas.

Only outline is in the 1 to realize that the first partial exhaust manifold 5 several exhaust ducts 16 having each exhaust inlet 2 such exhaust system 16 associated is. Through the exhaust system 16 this is done by the respective exhaust inlet 2 entering exhaust gas in the direction of the second partial exhaust manifold 6 guided. Each exhaust system is via at least one overflow opening, not shown here 17 with the exhaust pipe 11 of the second partial exhaust manifold 6 flow-connected.

The 2 shows an exploded view of the of 1 known exhaust manifold 1 , It now becomes clear that the exhaust pipe 11 as from the manifold jacket 12 exists separate sheet metal component, wherein the sheet metal of the sheet metal component is in particular a thin sheet with a wall thickness of at most 3 mm. The manifold jacket 12 is in turn made up of several parts and consists of a lower shell 18 and an upper shell 19 , which in the assembly of the exhaust manifold 1 connected by welding or to the first Teilabgaskrümmer 5 be connected. The same applies to the exhaust pipe 11 , which in the region of the overflow openings 17 also by welding to the first partial exhaust manifold 5 is attached. Welds made by welding 13 should be arranged so that they by means of the mass sheath 7 can be cooled during operation of the internal combustion engine. In this way, the welds become 13 protected from excessive thermal stress, so that there is no failure of the welds 13 and thus damage to the exhaust manifold 1 can come.

Due to the multi-part construction of the exhaust manifold 1 , wherein the first partial exhaust manifold 5 as a cast component and the second partial exhaust manifold 6 is present as a sheet metal component, in particular sheet metal welding component, the weight and the cost of the exhaust manifold 1 be significantly reduced. This is the case in particular if only elements of the exhaust manifold which are subjected to particularly high thermal stress are used 1 immediately after the exhaust inlet 2 , so the first partial exhaust manifold 5 , are coolable, while thermally lower loaded elements such as the second partial exhaust manifold 6 are not cooled, so have no own active cooling. Of course, however, heat from the second Teilabgaskrümmer 6 on the first partial exhaust manifold 5 go over and be derived from there via the coolant. Nevertheless, the temperature of the second partial exhaust manifold 6 usually higher than that of the first partial exhaust manifold 5 because only the former is actively cooled. For this reason, there is the second partial exhaust manifold 6 at least partially made of a high temperature resistant material, in particular a high temperature resistant sheet. This applies in particular to the exhaust pipe 11 , but advantageously also for the manifold jacket 12 ,

Due to the multi-part design of the exhaust manifold 1 can the water jacket 7 be adapted to the dissipated amount of heat. Depending on the capacity of the cooling device or the achievable reduction in the temperature of the exhaust gas in the exhaust manifold 1 can the water jacket 7 be made larger or smaller. The design of the first partial exhaust manifold 5 As cast component offers great freedom of design. Corners and edges that could increase the flow resistance for the coolant can be avoided. In addition, with the multi-part design of the exhaust manifold 1 an advantage over a fully designed as a cast component exhaust manifold 1 achieved.

Due to its large mass, a conventional exhaust manifold has a high heat capacity, so stores a lot of heat. Usually, when switching off the internal combustion engine and a coolant pump is stopped, so that the coolant is no longer in the water jacket 7 the exhaust manifold 1 circulated. Accordingly, in the exhaust manifold 1 still existing heat can not be dissipated, which can cause boiling of the coolant. This could only be controlled by large-volume follower pumps. Is the exhaust manifold 1 in contrast, in the presented here multi-part design, so the second partial exhaust manifold 6 a significantly lower heat capacity than the first partial exhaust manifold 5 , Accordingly, the heat capacity of the entire exhaust manifold 1 reduced, so that the secondary pump can be omitted or can be made considerably smaller. Furthermore, the exhaust manifold 1 be designed so that the highest thermal stress region is present in the second partial exhaust manifold. Accordingly, although for the second partial exhaust manifold 6 a high temperature resistant material can be used, due to the at least partially formed at least the exhaust pipe 11 however, the use of material in sheet metal is low in comparison to a cast component. The by means of the water jacket 7 cooled first partial exhaust manifold 5 On the other hand, it is not so highly thermally stressed, so it can be made of a less expensive material.

LIST OF REFERENCE NUMBERS

1

exhaust manifold

2

inlet

3

outlet

4

outlet flange

5

1st partial exhaust manifold

6

Partial exhaust manifold

7

water jacket

8th

Water jacket cover

9

Coolant inlet

10

inlet flange

11

exhaust pipe

12

Krümmermantel

13

Weld

14

admission

15

Through opening

16

exhaust system

17

overflow

18

lower shell

19

upper shell

Claims (10)

Exhaust manifold ( 1 ) for an internal combustion engine, the at least one connectable to a combustion chamber outlet of the internal combustion engine exhaust inlet ( 2 ) and a downstream of the exhaust gas inlet ( 2 ) arranged exhaust outlet ( 3 ) for exhaust gas of the internal combustion engine, characterized in that the exhaust manifold ( 1 ) from at least one partial exhaust manifold ( 5 ) and a downstream of the first partial exhaust manifold ( 5 ) second partial exhaust manifold ( 6 ), the first partial exhaust manifold ( 5 ) a water jacket ( 7 ) and at least one exhaust gas carrying exhaust pipe ( 11 ) of the second partial exhaust manifold ( 6 ) is at least partially present as a sheet metal component. Exhaust manifold according to claim 1, characterized in that the entire second partial exhaust manifold ( 6 ) is present as a sheet metal component. Exhaust manifold according to one of the preceding claims, characterized in that the second partial exhaust manifold ( 6 ) approaches over a tail ( 13 ) on the first partial exhaust manifold ( 5 ) is attached. Exhaust manifold according to one of the preceding claims, characterized in that the first partial exhaust manifold ( 5 ) as cast component with integrated water jacket ( 7 ) is present. Exhaust manifold according to one of the preceding claims, characterized in that the second partial exhaust manifold ( 6 ) one the exhaust outlet ( 3 ) receiving outlet flange ( 4 ) of the exhaust manifold ( 1 ) having. Exhaust manifold according to one of the preceding claims, characterized in that the second partial exhaust manifold ( 6 ) at least one, a wall of the sheet-metal component by cross-recording ( 14 ) for an exhaust gas sensor. Exhaust manifold according to one of the preceding claims, characterized in that the second partial exhaust manifold ( 6 ) has a lower heat capacity than the first partial exhaust manifold ( 5 ). Exhaust manifold according to one of the preceding claims, characterized in that the second partial exhaust manifold ( 6 ) at least from the at least one exhaust pipe ( 11 ) and one the exhaust pipe ( 11 ) surrounding manifold jacket ( 12 ) consists. Exhaust manifold according to one of the preceding claims, characterized in that the exhaust pipe ( 11 ) of the second partial exhaust manifold ( 6 ) via at least one overflow opening ( 17 ) with at least one exhaust system ( 16 ) of the first partial exhaust manifold ( 5 ) is fluidly connected. Exhaust manifold according to one of the preceding claims, characterized in that in the second partial exhaust manifold ( 5 ) several exhaust pipes ( 11 ), which are located upstream of the exhaust gas outlet ( 3 ) are brought together.

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