DE10144015A1 - Exhaust system for multi-cylinder internal combustion engines - Google Patents

Abstract

Exhaust system for multicylinder internal combustion engines comprises an exhaust gas manifold with an arrangement consisting of exhaust gas pipes and at least one exhaust gas catalyst (3) branching in the direction of the engine and connected on one engine side to its exhaust gas outlet openings. The exhaust gas outlet side of the branched exhaust pipe arrangement is formed by two adjacent gas outlet openings, each flow-connected to one part of the branched exhaust pipes and to which is connected a pipe (13', 13'') of a double pipe arrangement (13) having two parallel pipes. The other gas outlet side end opens into a flow sleeve (16) arranged in front of the exhaust gas catalyst. Preferred Features: The double pipe arrangement is guided up to just before the lambda sensor (17) of the exhaust gas catalyst and/or the lambda sensor is arranged in the flow sleeve.

Description

The present invention relates to an exhaust system for multi-cylinder Internal combustion engines with an exhaust manifold with one in Direction towards the engine, on one side of the engine Exhaust outlet openings connectable arrangement of exhaust pipes and at least one catalytic converter.

Modern exhaust systems need a variety of partial ones meet conflicting requirements. So is sufficient to achieve Exhaust gas cleaning requires a significant volume of catalyst, what often only by dividing the total volume into several Exhaust gas catalysts can be achieved. In addition, the engine compartment space available for the exhaust system due to additional Aggregates and more compact design always smaller.

The invention has for its object an exhaust system of the beginning Specify the type mentioned, the requirements as well as possible Fulfills. In particular, an exhaust system is to be created, which in Engine compartment takes up little space and has a good cleaning effect having.

This object is achieved in that the gas outlet side of the branched exhaust pipe arrangement by two side by side Gas outlet openings are formed, with each of which part of the branched Exhaust pipes are in flow connection and each have a pipe a double pipe arrangement with two parallel ones running side by side Pipes is connected, the other, gas outlet end in a flow sleeve arranged in front of the catalytic converter opens into which the catalyst inflow is designed.

This double pipe arrangement can be a good one Emission control performance can be achieved with a relatively small footprint. In particular, it is possible due to this configuration, the entire Catalytic converter volume for one engine side in a single catalytic converter housing accommodate. So it will not be a pre-catalytic converter Underbody catalyst required, as is often the case otherwise. With that Not only does it take up less space and cut costs, it does there is also no double catalyst control. In addition, that can Total catalyst volume brought particularly close to the engine be what benefits the cleaning performance of the catalyst. In the flow sleeve is created a mixing zone in which the Flow is redesigned to optimal catalyst flow to reach.

The double pipe arrangement is preferred until just before the so-called Exhaust gas catalytic converter lambda probe guided. This results in a particularly long dual flow, which is advantageous for exhaust gas cleaning. In addition, the long double flow has the advantage that the cylinder influence each other less because there is less overlap in the Exhaust gas flows occur.

The lambda probe is arranged in particular in the flow sleeve, So in an area where the exhaust gas flow has already been redesigned. The measured values obtained are therefore particularly meaningful.

The flow sleeve is preferred in order to achieve a nozzle effect Direction towards the catalytic converter tapered in diameter. The exhaust gas flow can thus do particularly well in the desired manner be designed.

A design of the cross section of the pipes is also advantageous Double-tube arrangement in D-shape, the tubes with their flattened Side facing each other. The space requirement of the double pipe arrangement can be kept low.

A further reduction in space requirements results when the two Pipes of the double pipe arrangement in a common housing are accommodated.

The accommodation in a common housing is also in the branched arrangement of exhaust pipes advantageous. In particular, the Exhaust system kept particularly compact in the engine area become.

According to a further embodiment of the invention, the two are Gas outlet openings of the branched exhaust pipe arrangement with respect to the Centered longitudinally of the arrangement. This also supports you compact design of the exhaust system near the engine.

Furthermore, the exhaust system is preferably of modular construction, with a first module comprising the branched exhaust pipe arrangement and a second module comprising the double pipe arrangement. On Such a modular structure has the advantage that for different Installation situations, partly the same components can be used. For example, the module comprising the double pipe arrangement could can be used for both 8-cylinder and 12-cylinder engines. Or it can be one and the same module for right-hand drive vehicles as well can be used for left-hand drive vehicles.

A further improvement in this regard can be achieved be that the first module in relation to the connecting line of the Exhaust gas inlet openings vertical center plane of the module symmetrical is trained. This means in particular that the two Gas outlet openings of the branched exhaust pipe arrangement in the middle and straight behind are arranged on the outside, so that this module on both engine sides can be used and only the second, the double tube arrangement containing module is designed depending on the page.

The housings of the branched exhaust pipe arrangement and the are preferred Double tube arrangement designed as load-bearing elements, while the exhaust pipes running therein, in particular by means of wire mesh rings, floating and only permanently connected to the housing on one side, in particular are welded. It may be sufficient if the branched exhaust pipe arrangement fixed on the engine side with its housing is connected, while the pipes of the double pipe arrangement with the branched Exhaust pipe arrangement and with the flow sleeve through sliding seat are connected.

The housing of the branched exhaust pipe arrangement, the Double pipe arrangement and the flow sleeve are preferred in each case welded together. Likewise, the flow sleeve is preferred with the Exhaust catalytic converter housing welded. The attachment of the housing The branched exhaust pipe arrangement on the engine, however, takes place as usual through flanges. Such an embodiment has both from Space requirements as well as the manufacture were found to be advantageous.

According to a further embodiment of the invention, which also for itself is claimed, the exhaust pipes of the branched exhaust pipe assembly together with their housing in top view on the level of Gas inlet openings following a wavy line alternately upwards and downwards curved below that next to the exhaust gas inlet openings. Clearances for access to the screw bushings for the Attachment of the exhaust system to the engine. The assembly of the Exhaust system can be significantly simplified. In addition, the wave-shaped design has the advantage that thermal expansion of the housing that is firmly attached to the motor can, so that lower thermal stresses occur.

According to a further embodiment of the invention, which is also for is claimed, the housing is the branched Exhaust pipe arrangement at least once in the direction of the connecting line of the Exhaust gas inlet openings divided, the parts via flexible elements, especially bellows, are interconnected. Through this too Design can compensate for thermal expansion of the housing be so that thermal stresses are reduced. This is particularly so important for multi-cylinder engines such as 12-cylinder engines where the housing is relatively large. With these is the housing preferably divided into three parts, in particular two corrugated bellows.

A can also be used for the double tube arrangement and the flow sleeve common housing may be provided. The manufacturing and Assembly costs can thereby be reduced.

The housings preferably each consist of two sheet metal half shells. The Exhaust pipes are made especially by internal high pressure forming manufactured. Both are advantageous in terms of production technology.

Embodiments of the invention are shown in the drawing and are described below.

They show, each in a schematic representation,

Fig. 1 is a plan view of a first variant of an exhaust system according to the invention,

Fig. 2 is a view of a portion of the exhaust system of FIG. 1 in a slightly enlarged scale;

Fig. 3 is a partially sectioned view of the part of Fig. 2,

Fig. 4 is a partially sectioned view of another portion of the exhaust system of FIG. 1,

Fig. 5 is a view in the direction of arrow X in Fig. 4,

Fig. 6 is a plan view of a second variant of an exhaust system according to the invention,

Fig. 7 is a section along line AA in Fig. 6 and

Fig. 8 shows a section through a part of the exhaust system of Fig. 6.

The exhaust system shown in FIGS. 1 to 5 comprises a first exhaust gas outlet openings with an internal combustion engine to be connected to module 1, one end connected to the first module 1 and a second module 2 connected to the second module 2 exhaust gas catalytic converter 3. The first module 1 comprises a housing 4 , which accommodates an arrangement of branched exhaust pipes 5 . As can be seen in particular in FIGS. 2 and 3, the branched exhaust pipes 5 lead on the one hand into six exhaust gas inlet openings 6 and on the other hand into two adjacent exhaust gas outlet openings 7 . The branched exhaust pipes 5 each comprise here two individual tubes 5 ', 5 "and 5' '', which are inserted with a sliding fit into one having two exhaust gas outlet openings 7 manifolds 5 ^IV, where the header pipes 5 ^IV in the field of exhaust gas exit ports 7 in cross-section D -shaped and are arranged with their flattened side opposite each other.

The housing 4 consists of two sheet metal half-shells 4 'and 4 ", which are welded together and surround the arrangement of branched exhaust pipes 5 with the formation of an air gap 8 at a short distance. The housing also comprises three parts 4 a, b, c, which have two Corrugated bellows 9 are connected to one another.

In the area of the exhaust gas inlet openings 6 , the housing 4 has fastening flanges 10 , which are partially assigned to one exhaust gas inlet opening 6 , partially to two exhaust gas inlet openings 6 . The flanges 10 are connected to the housing 4 by welding. The arrangement of branched exhaust pipes 5 is also welded to the housing 4 in the region of the exhaust gas inlet opening 6 . Otherwise, the individual tubes 5 'to 5 ^IV are connected to one another by a sliding fit.

The flanges 10 are provided in the area of each exhaust gas inlet opening 6 with two screw bushings 11 , by means of which the exhaust system can be attached to an internal combustion engine. As can be seen in particular in FIGS. 1 and 2, the housing 4 and the branched exhaust pipes 5 are formed in a wave-like manner in a plane parallel to the plane of the flanges 10 in such a way that the screw bushings 11 are kept free for access directed perpendicularly to this plane. Accordingly, the two screw bushings 11 are arranged alternately opposite one another in the area of each exhaust gas inlet opening 6 in the one and the other direction.

The second module 2 comprises a housing 12 made of two sheet metal half-shells 12 'and 12 ", in which, as can be seen in particular in FIGS. 4 and 5, a double pipe arrangement 13 made of two exhaust pipes 13 ' and 13 " running parallel to one another is arranged. The two tubes 13 'and 13 "of the double tube arrangement are D-shaped in cross section and are arranged opposite one another with their flattened sides 14 ', 14 ". In the area of their exhaust gas inlet openings 15 'and 15 ", the two exhaust pipes 13 ' and 13 " are designed in cross-section so that they can be connected to the gas outlet-side ends of the two manifolds 5 ^IV with a sliding fit.

With its other end, the two exhaust pipes 13 'and 13 "of the double-tube arrangement 13, also with a sliding fit, is inserted into a flow sleeve 16, which is likewise arranged in the housing twelfth The flow sleeve 16 is tapered in the flow direction I formed, and has in its tapered A receptacle 17 for a lambda probe in region 16 ', the flow sleeve 16 , again with a sliding seat, is inserted into the housing 19 of the exhaust gas catalytic converter 3 with its gas outlet end 18 .

All exhaust pipes 5 , 13 and 16 are thus floating within the housing 4 , 12 . They are held in the radial direction relative to the housings 4 , 12 which represent the supporting parts by means of wire mesh rings 20 . Only the exhaust pipes 5 ′, 5 ″ and 5 ″ ″ of the branched exhaust pipe arrangement 5 are, as already stated, firmly connected to the housing 4 by welding on the exhaust gas inlet side.

At its gas outlet end, the exhaust gas catalytic converter 3 has a flange 21 for connection to further exhaust pipes, not shown here. In this case, no further exhaust gas catalysts are preferably provided in the exhaust line, that is to say the entire catalyst volume is accommodated in one exhaust gas catalytic converter 3 .

The exhaust gas outlet openings 7 of the manifolds 5 ^IV are arranged symmetrically around the central plane II of the module 1 , which runs perpendicular to the connecting line of the exhaust gas inlet openings 6 . The other elements of the first module 1 are also preferably symmetrical in relation to this central plane II. The exhaust pipes 5 and 13 and the flow sleeve 16 are preferably produced by internal high pressure forming.

In the variant shown in FIGS. 6 to 8, the exhaust system also comprises two modules 1 and 2 and an exhaust gas catalytic converter 3 . In contrast to the first variant, however, the second module 2 is constructed in two parts, with a first part 2 ′ and a second part 2 ″. The first part 2 ′ comprises the double pipe arrangement 13 and the housing 12 a surrounding it, while the second part 2 "the flow sleeve 16 and a surrounding this separate housing 12 includes b. The two housings 12 a and 12 b are connected to one another by welding.

Another difference from the first variant is that the arrangement of branched exhaust pipes 5 has only four exhaust gas inlet openings 6 . The branched exhaust pipe arrangement 5 comprises two simple, curved exhaust pipes 5 ', which are each fitted with a sliding fit in one of two branched exhaust pipes 5 ^V , the other branch of which each forms one of the exhaust gas inlet openings 6 and the other ends form the exhaust gas outlet openings 7 of the branched exhaust pipe arrangement 5 . As can be seen in FIG. 8, the two tubes 13 ′, 13 ″ of the double tube arrangement 13 are also arranged in parallel in this variant and open on the exhaust gas outlet side with a sliding seat in the flow sleeve 16 , which in turn has a receptacle 17 for the lambda probe in a tapered section 16 ′ The flow sleeve 16 , too, is in turn inserted with a sliding fit into the housing 19 of the exhaust gas catalytic converter 3 , which preferably contains the entire catalytic converter volume, so here too no further catalytic converter is provided in this exhaust gas line.

As can also be seen in FIG. 8, the two tubes 13 ′, 13 ″ of the double tube arrangement 13 are guided on the exhaust gas outlet side up to shortly before the lambda probe. A mixing zone 22 is thereby formed in the region of the lambda probe, in which the exhaust gas flow with the help of the flow sleeve 16 is new The exhaust gas flow can thus be designed in the desired manner in order to optimize the flow against the catalyst 3. A corresponding mixing chamber 22 is also present in the first variant.

As can be seen in the figures, the entire catalyst volume is accommodated particularly close to the engine. This improves the catalyst performance. By using modules, the individual parts of the exhaust system can be used for different purposes. Thus, the first module 1 of the first variant can be used for the left as well as for the right engine side due to its symmetrical configuration with respect to the center plane II. In principle, the second modules 2 can each be used in connection with different first modules 1 , for example optionally with modules 1 with four or six exhaust gas inlet openings 6 .

The invention creates a particularly compact exhaust system that can make do with an exhaust gas catalytic converter 3 . This allows the catalyst volume to be brought very close to the engine. The exhaust gas flow can be shaped in the flow sleeve 16 , which acts as a mixing chamber, and an optimal flow against the exhaust gas catalytic converter 3 can thereby be achieved. The long double flow through the double pipe arrangement 13 also has the advantage that the exhaust gas flows of the cylinders can influence one another less.

The exhaust system according to the invention is also, particularly due to the modular structure, inexpensive to manufacture and, especially because of the wave-shaped shape of the exhaust pipes 5 , in the assembly. The thermal stresses in the housing 4 are also reduced due to the wave-shaped design. The bellows 9 between the three parts 4 a, b, c of the housing 4 also serve this purpose. REFERENCE NUMERALS 1 first module
2 second module
3 catalytic converter
4 housing
4 ', 4 "half shell of 4
4 a, b, c parts of 4
5 branched exhaust pipe arrangement
5 '- 5 ^V exhaust pipe
6 exhaust gas inlet opening
7 Exhaust outlet
7 ', 7 "side of 7
8 air gap
9 corrugated bellows
10 motor flange
11 screw bushing
12 housing
12 ', 12 "parts of 12
13 double pipe arrangement
13 ', 13 "exhaust pipe from 13
14 ', 14 "pages of 13 ', 13 "
15 ', 15 "exhaust gas inlet opening of 13 ', 13 "
16 flow sleeve
16 'section of 16
17 Lambda probe holder
18 end of 16
19 housing of 3
20 wire knitted ring
21 flange
22 mixing zone
I Exhaust gas flow direction
II middle level

Claims (20)

1. Exhaust system for multi-cylinder internal combustion engines with an exhaust manifold with a branching in the direction of the engines, on an engine side to its exhaust outlet openings connectable arrangement of exhaust pipes ( 5 ) and at least one exhaust gas catalytic converter ( 3 ), characterized in that the exhaust outlet side of the branched exhaust pipe arrangement ( 5 ) is formed by two gas outlet openings ( 7 ) lying next to each other, with each of which a part of the branched exhaust pipes ( 5 ) is in flow connection and to each of which a pipe ( 13 ', 13 ") of a double pipe arrangement ( 13 ) with two pipes running parallel to one another ( 13 ', 13 ") is connected, the other, gas outlet-side end opens into a flow sleeve ( 16 ) arranged in front of the exhaust gas catalytic converter ( 3 ), in which the flow towards the catalytic converter is designed. 2. Exhaust system for multi-cylinder internal combustion engines according to claim 1, characterized in that the double tube arrangement ( 13 ) is guided up to shortly before the so-called lambda probe ( 17 ) of the exhaust gas catalytic converter ( 3 ). 3. Exhaust system for multi-cylinder internal combustion engines according to claim 1 or 2, characterized in that the lambda probe ( 17 ) of the exhaust gas catalytic converter ( 3 ) is arranged in the flow sleeve ( 16 ). 4. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the flow sleeve ( 16 ) is tapered in diameter in order to achieve a nozzle effect in the direction of the exhaust gas catalytic converter ( 3 ). 5. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the tubes ( 13 ', 13 ") of the double tube arrangement ( 13 ) in cross-section D-shaped and with their flattened side ( 14 ', 14 ") facing each other are. 6. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the tubes ( 13 ', 13 ") of the double tube arrangement ( 13 ) are arranged in a common housing ( 12 ). 7. Exhaust system for multi-cylinder internal combustion engines according to claim 6, characterized in that a common housing ( 12 ) is provided for the double pipe arrangement ( 13 ) and the flow sleeve ( 16 ). 8. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the tubes ( 5 ) of the branched exhaust pipe arrangement are arranged in a common housing ( 4 ). 9. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that at least the major part of the catalyst volume, in particular the entire catalyst volume, of the exhaust gas system is arranged in the exhaust gas catalytic converter ( 3 ) following the flow sleeve ( 16 ). 10. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the double pipe arrangement ( 13 ) with respect to the connecting line of the exhaust gas inlet openings ( 6 ) perpendicular to the central plane (II) of the module ( 1 ) in the middle of the branched exhaust pipe arrangement ( 5 ) connected. 11. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the exhaust system is constructed in a modular manner, with a first module ( 1 ) comprising the branched exhaust pipe arrangement ( 5 ) and a second module ( 2 ) comprising the double pipe arrangement ( 13 ) ). 12. Exhaust system for multi-cylinder internal combustion engines according to claim 11, characterized in that the first module ( 1 ) at least with respect to the connection for the second module ( 2 ) with respect to its perpendicular to the connecting line of the exhaust gas inlet openings ( 6 ) extending central plane (II) symmetrical is trained. 13. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the housing ( 4 , 12 ) are designed as the supporting elements, while the exhaust pipes ( 5 , 13 , 16 ) are floatingly mounted therein and only on one side with the housing ( 4 ) firmly connected, in particular welded. 14. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the branched exhaust pipe arrangement ( 5 ) is connected on the motor side to its housing ( 4 ), while the pipes ( 13 ', 13 ") of the double pipe arrangement ( 13 ) with the branched Exhaust pipe arrangement ( 5 ) and the flow sleeve ( 16 ) are connected by a sliding seat. 15. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the housing ( 4 ) of the branched exhaust pipe arrangement ( 5 ) with the housing ( 12 ) of the double pipe arrangement ( 13 ), this with the housing ( 21 ) of the flow sleeve ( 16 ) and this in turn is firmly connected to the housing ( 22 ) of the catalyst ( 3 ), in particular welded. 16.Exhaust system for multi-cylinder internal combustion engines with an exhaust manifold with an arrangement of exhaust pipes ( 5 ) and at least one exhaust gas catalytic converter ( 3 ), in particular according to one of the preceding claims, characterized in that it branches off in the direction of the engine and can be connected on one engine side to its exhaust outlet openings. that the exhaust pipes ( 5 ) of the branched exhaust pipe arrangement together with their housing ( 4 ) in plan view of the plane of the exhaust gas inlet openings ( 6 ) following a wavy line are alternately curved upwards and downwards such that in addition to the exhaust gas inlet openings ( 6 ) there are free spaces for access to the screw bushings ( 11 ) for fastening the exhaust system to the engine. 17. Exhaust system for multi-cylinder internal combustion engines with an exhaust manifold with a branching in the direction of the engine, on one engine side to the exhaust outlet openings connectable arrangement of exhaust pipes ( 5 ), at least one catalytic converter ( 3 ) and one surrounding the branched exhaust pipe arrangement ( 5 ), fixed Housing ( 4 ) connectable to the engine, in particular according to one of the preceding claims, characterized in that the housing ( 4 ) is divided at least once in the direction of the connecting line of the exhaust gas inlet openings ( 6 ), the parts ( 4 a, b, c) are connected to one another via flexible elements, in particular corrugated bellows ( 9 ). 18. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the housings ( 4 , 12 ) each consist of sheet metal and comprise two half-shells ( 4 ', 4 "; 12 ', 12 "). 19. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the exhaust pipes ( 5 , 13 ) are made by internal high pressure forming. 20. Exhaust system for multi-cylinder internal combustion engines according to one of the preceding claims, characterized in that the branched exhaust pipe arrangement ( 5 ) has four or six exhaust gas inlet openings ( 6 ).