EP1291500B1 - Exhaust device for multicylinder 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 according to the preamble of claim 1. Such an exhaust system is made Kandylas, JP et al. "Engine exhaust system design based on heat transfer computation", Energy Conversion and Management, Elsevier Science Publishers, Oxford, GB, Vol. 40, No. 10, July 1999 (1999-07), pages 1057-1072 , XP 004162444, JSSN: 0196-8904.

Modern exhaust systems must meet a variety of partially conflicting requirements. Thus, to achieve a sufficient exhaust gas purification, a considerable catalyst volume is required, which can often only be achieved by dividing the total volume into several catalytic converters. Moreover, the space available in the engine compartment for the exhaust system becomes smaller and smaller due to additional units and a more compact design.

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

This object is solved by the features of claim 1.

Through this double tube arrangement, a good emission control performance can be achieved with relatively little space. In particular, it is possible due to this configuration to accommodate the entire catalyst volume for an engine side in a single catalyst housing. So it is no pre-catalyst and no underfloor catalyst needed, as is often the case. This not only reduces the space requirement and reduces costs, but it also eliminates a double catalyst control. In addition, the overall catalyst volume can be brought particularly close to the engine, which benefits the cleaning performance of the catalyst. In the flow sleeve while a mixing zone is created, in which the flow is redesigned to achieve optimum catalyst flow.

Preferably, the double pipe arrangement is led to just before the so-called lambda probe of the catalytic converter. This results in a particularly long Zweiflutigkeit, which is advantageous for the emission control. In addition, the long Zweiflutigkeit has the advantage that the cylinders influence each other less, since there are fewer overlaps in the exhaust gas flows.

The lambda probe is arranged in the flow sleeve, ie in a region in which the exhaust gas flow is already redesigned. The measured values obtained are therefore particularly meaningful.

The flow sleeve is designed to achieve a nozzle effect preferably tapered in the direction of the catalytic converter in diameter. Thus, the exhaust gas flow can be particularly well designed in the desired manner.

A further advantage is a design of the cross section of the tubes of the double tube arrangement in D-shape, wherein the tubes are facing each other with their flattened side. The space requirement of the double pipe arrangement can be kept low.

A further reduction in the space required results when the two tubes of the double tube assembly are housed in a common housing.

Housing in a common housing is also advantageous in the branched arrangement of exhaust pipes. In particular, the exhaust system can thereby be kept particularly compact in the engine area.

According to the invention, the two gas outlet openings of the branched exhaust pipe arrangement are arranged centrally with respect to the longitudinal direction of the arrangement. This also promotes a compact design of the exhaust system in the vicinity of the engine.

Furthermore, the exhaust system is preferably constructed modularly, with a first module comprising the branched exhaust pipe arrangement and a second module comprising the double pipe arrangement. One Such modular construction has the advantage that partially identical components can be used for different installation situations. For example, the module comprising the double tube assembly could find application in both 8-cylinder and 12-cylinder engines. Or one and the same module can be used for both right-hand drive and left-hand drive vehicles.

A further improvement in this regard can be achieved in that the first module is formed symmetrically with respect to the center plane of the module perpendicular to the line connecting the exhaust gas inlet openings. This means, in particular, that the two gas outlet openings of the branched exhaust pipe arrangement are arranged centrally and pointing straight outwards, so that this module can be used on both sides of the engine and only the second, the double pipe arrangement containing module is formed side by side.

Preferably, the housing of the branched exhaust pipe arrangement and the double pipe arrangement are designed as load-bearing elements, while the exhaust pipes extending therein, in particular by means of Drahtgestrickringen, floatingly mounted and only one side firmly connected to the housing, in particular welded. It may be sufficient if the branched exhaust pipe arrangement is fixedly connected to the motor side with its housing, while the tubes of the double pipe arrangement are connected to the branched exhaust pipe arrangement and with the flow sleeve by sliding fit.

The housings of the branched exhaust pipe arrangement, the double pipe arrangement and the flow sleeve are preferably each with each other welded. Likewise, the flow sleeve is preferably welded to the housing of the catalytic converter. The attachment of the housing of the branched exhaust pipe arrangement on the engine, however, takes place as usual by flanges. Such a configuration has proven to be advantageous both from the space and from the production ago.

According to a further embodiment of the invention, which is also claimed for itself, the exhaust pipes of the branched exhaust pipe assembly together with its housing in plan view of the plane of the gas inlet openings of a wavy line following such curved alternately upwards and downwards formed that in addition to the exhaust gas inlet openings for the Access to the screw holes for attaching the exhaust system to the engine are formed. The assembly of the exhaust system can be significantly simplified. In addition, the wave-shaped configuration has the advantage that thermal expansion of the fixed motor-mounted housing can be better absorbed, so that lower thermal stresses occur.

According to a further embodiment of the invention, which is also claimed for itself, the housing of the branched exhaust pipe assembly is divided at least once in the direction of the connecting line of the exhaust gas inlet openings, wherein the parts via flexible elements, in particular corrugated bellows, are interconnected. Also by this configuration, thermal expansion of the housing can be compensated, so that thermal stresses are reduced. This is particularly important in multi-cylinder engines, such as 12-cylinder engines, where the housing is relatively large. These are the housings preferably divided into three parts, so in particular two bellows provided.

For the double pipe arrangement and the flow sleeve, a common housing may also be provided. The manufacturing and assembly costs can be reduced.

The housings preferably each consist of two sheet metal half shells. The exhaust pipes are produced in particular by hydroforming. Both are manufacturing technology advantageous.

Embodiments of the invention are illustrated in the drawings and will be described below.

Fig. 1

eine Draufsicht auf eine erste Variante einer erfindungsgemäßen Abgasanlage,

Fig. 2

eine Ansicht eines Teils der Abgasanlage von Fig. 1 in etwas vergrößerter Darstellung,

Fig. 3

eine teilweise geschnittene Darstellung des Teils von Fig. 2,

Fig. 4

eine teilweise geschnittene Darstellung eines anderen Teils der Abgasanlage von Fig. 1,

Fig. 5

eine Ansicht in Richtung des Pfeils X in Fig. 4,

Fig. 6

eine Draufsicht auf eine nicht erfindungsgemäßen Abgasanlage,

Fig. 7

einen Schnitt gemäß Linie A - A in Fig. 6 und

Fig. 8

einen Schnitt durch einen Teil der Abgasanlage von Fig. 6.

They show, in each case in a schematic representation,

Fig. 1

a plan view of a first variant of an exhaust system according to the invention,

Fig. 2

a view of a portion of the exhaust system of Fig. 1 in a slightly enlarged view,

Fig. 3

a partially sectioned view of the part of Fig. 2 .

Fig. 4

a partially sectioned view of another part of the exhaust system of Fig. 1 .

Fig. 5

a view in the direction of the arrow X in Fig. 4 .

Fig. 6

a top view of a non-inventive exhaust system,

Fig. 7

a section along line A - A in Fig. 6 and

Fig. 8

a section through a part of the exhaust system of Fig. 6 ,

The in the FIGS. 1 to 5 illustrated exhaust system comprises a first with exhaust gas outlet openings of an internal combustion engine to be connected module 1, connected to the first module 1 second module 2 and connected to the second module 2 exhaust catalyst 3. The first module 1 comprises a housing 4, which is an arrangement of branched exhaust pipes 5 takes up. As in particular in the FIGS. 2 and 3 detects the branched exhaust pipes 5 on the one hand in six exhaust gas inlet openings 6 and on the other hand in two juxtaposed exhaust gas outlet openings 7. The branched exhaust pipes 5 each comprise two individual tubes 5 ', 5 "and 5''', with the sliding seat in one of two the exhaust gas outlet openings. 7 having manifolds 5 ^IV are used, wherein the manifolds 5 ^{IV formed} in the region of the exhaust gas outlet openings 7 in cross-section D-shaped and are arranged opposite each other with their flattened side.

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 a small gap to form an air gap 8. The housing also comprises three parts 4 a, b, c, over two Bellows 9 are interconnected.

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

The flanges 10 are provided in the region of each exhaust gas inlet opening 6 with two screw feedthroughs 11, by means of which the exhaust gas system can be fastened to an internal combustion engine. As in particular in the Fig. 1 and 2 detects, the housing 4 and the branched exhaust pipes 5 are formed in a plane parallel to the plane of the flanges 10 such a wave-shaped, that the screw penetrations 11 are kept free for a directed perpendicular to this plane access. Accordingly, the two screw penetrations 11 in the region of each exhaust gas inlet opening 6 are arranged alternately in one and the other direction opposite to each other.

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

At the other end, the two exhaust pipes 13 'and 13 "of the double pipe arrangement 13, also with a sliding fit, are inserted into a flow sleeve 16, which is likewise arranged in the housing 12. The flow sleeve 16 is tapered in the flow direction I and has its tapered end Area 16 'a receptacle 17 for a lambda probe with its gas outlet end 18, the flow sleeve 16, again with a sliding fit, inserted into the housing 19 of the catalytic converter 3.

All exhaust pipes 5, 13 and 16 are thus floating within the housing 4, 12. By means of wire knit rings 20, they are held in the radial direction relative to the housing 4, 12 representing the supporting parts. 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 catalytic converter 3 has a flange 21 for connection to further, not shown exhaust pipes. In this case, no further exhaust gas catalysts are preferably provided in the exhaust gas line, that is to say the entire catalyst volume is accommodated in the one exhaust gas catalytic converter 3.

The exhaust gas outlet openings 7 of the manifolds 5 ^IV are arranged symmetrically about the perpendicular to the line connecting the exhaust gas inlet openings 6 extending center plane II of the module 1. The rest, too Elements of the first module 1 are preferably formed symmetrically with respect to this center plane II. The exhaust pipes 5 and 13 and the flow sleeve 16 are preferably made by hydroforming.

In the in the Fig. 6 to 8 illustrated variant, the exhaust system also includes two modules 1 and 2 and an exhaust gas catalyst 3. In contrast to the first variant, the second module 2, however, formed in two parts, with a first part and a second part. The first part comprises the double tube assembly 13 and the surrounding housing 12 ', while the second part comprises the flow sleeve 16 and a separate housing 12 "surrounding it. The two housings 12' and 12" are joined together 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 assembly 5 comprises two simple, curved exhaust pipes 5 ', which are inserted with sliding fit into one of two branched exhaust pipes 5 ^V , whose other branch forms one of the exhaust gas inlet openings 6 and the other end the exhaust gas outlet openings 7 of the branched exhaust pipe assembly 5 form.

As in Fig. 7 As can be seen, the two tubes 13 ', 13 "of the double tube arrangement 13 are also arranged parallel in this variant and open on the exhaust gas exit side with a sliding fit in the flow sleeve 16, which in turn has a receptacle 17 for the lambda probe in a tapered section 16' is in turn used with sliding fit into the housing 19 of the catalytic converter 3, which is preferred contains the entire catalyst volume. Again, no additional catalyst is provided in this exhaust system.

As well as in Fig. 7 As can be seen, the two tubes 13 ', 13 "of the double tube arrangement 13 are routed to the exhaust gas exit side until shortly before the lambda probe, thereby forming a mixing zone 22 in the region of the lambda probe, in which the exhaust gas flow is redesigned with the aid of the flow sleeve 16. The exhaust gas flow can thereby be formed in the desired manner in order to optimize the flow of 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 thus accommodated 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 both the left and 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 conjunction with different first modules 1, for example optionally with modules 1 with four or six exhaust gas inlet openings 6.

The invention provides a particularly compact exhaust system that can manage with an exhaust gas catalyst 3. This allows the catalyst volume to be brought very close to the engine. In the flow sleeve 16, which acts as a mixing chamber, the exhaust gas flow can be formed and thereby optimum flow of the catalytic converter 3 can be achieved. The long Zweiflutigkeit through the double tube assembly 13 also has the advantage that the exhaust gas flows of the cylinder can influence less each other.

The exhaust system according to the invention is also, in particular due to the modular structure, low in the production and, in particular because of the wavy shape of the exhaust pipes 5, in the assembly. Also, the thermal stresses in the housing 4 are reduced due to the undulating configuration. For this purpose, the corrugated bellows 9 between the three parts 4 a, b, c of the housing 4th

LIST OF REFERENCE NUMBERS

1

first module

2

second module

3

catalytic converter

4

casing

4 ', 4 "

Half shell of 4

4 a, b, c

Parts of 4

5

branched exhaust pipe arrangement

5'- ^5V

exhaust pipe

6

Exhaust gas inlet opening

7

Exhaust gas outlet opening

7 ', 7 "

Page of 7

8th

air gap

9

bellows

10

motor flange

11

Screw passage

12

casing

12 ', 12 "

Parts of 12

13

Double-tube arrangement

13 ', 13 "

Exhaust pipe of 13

14 ', 14 "

Pages from 13 ', 13 "

15 ', 15 "

Exhaust inlet of 13 ', 13 "

16

flow sleeve

16 '

Section of 16

17

Oxygen Sensor Recording

18

End of 16

19

Housing of 3

20

Wire mesh ring

21

flange

22

mixing zone

I

Exhaust gas flow direction

II

midplane

Claims (10)

1. An exhaust gas system for multicylinder internal combustion engines having an exhaust manifold with an arrangement of exhaust pipes (5) branching in the direction of the engine and connectable at the engine side to its exhaust gas outlet openings and having at least one catalytic converter (3), wherein the exhaust gas outlet side of the branched exhaust pipe arrangement (5) is formed by two adjacently disposed gas outlet openings (7) with which in each case some of the branched exhaust pipes (5) are in flow communication and to which in each case a pipe (13', 13") of a twin pipe arrangement (13) having two pipes (13', 13") extending parallel and adjacent to one another is connected whose other end at the gas outlet side opens into a flow sleeve (16) which is arranged before the catalytic converter (3) and in which the flow onto the catalytic converter is formed,
   characterised in that
   the lambda sensor (17) of the catalytic converter (3) is arranged in the flow sleeve (16); and in that the twin pipe arrangement (13) is connected centrally to the branched exhaust pipe arrangement (5) relative to the centre plane (II) of the module (1) including the branched exhaust pipe arrangement (5), said centre plane being perpendicular to the connection line of the exhaust inlet openings (6).
2. An exhaust gas system for multicylinder internal combustion engines in accordance with claim 1, characterised in that the twin pipe arrangement (13) is guided up to just before the so-called lambda sensor (17) of the catalytic converter (3).
3. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that the flow sleeve (16) is made with a converging diameter for the achieving of a nozzle effect in the direction of the catalytic converter (3); and/or in that the pipes (13' 13") of the twin pipe arrangement (13) are made in D-shape in cross-section and their flattened sides (14', 14") face one another.
4. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that the pipes (13', 13") of the twin pipe arrangement (13) are arranged in a common housing (12), with a common housing (12) preferably being provided for the twin pipe arrangement (13) and the flow sleeve (16); and/or in that the pipes (5) of the branched exhaust pipe arrangement are arranged in a common housing (4).
5. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that at least the predominant portion of the catalytic converter volume, in particular the total catalytic converter volume, of the exhaust tract is arranged in the catalytic converter (3) following the flow sleeve (16).
6. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that the exhaust gas system is made in modular form, with a first module (1) including the branched exhaust pipe arrangement (5) and a second module (2) including the twin pipe arrangement (13), wherein the first module (1) is preferably made symmetrical at least with respect to the connection for the second module (2) relative to its central plane (II) extending perpendicular to the connection line of the exhaust gas inlet openings (6); and/or in that the housings (4, 12) are made as the carrying elements, whereas the exhaust pipes (5, 13, 16) are supported in a floating manner therein and are only fixedly connected, in particular welded, to the housing (4) at one side.
7. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that the branched exhaust pipe arrangement (5) is connected to its housing (4) at the engine side, whereas the pipes (13', 13") of the twin pipe arrangement (13) are connected to the branched exhaust pipe arrangement (5) and to the flow sleeve (16) by a sliding seat; and/or in that the housing (4) of the branched exhaust pipe arrangement (5) is fixedly connected, in particular welded, to the housing (12) of the twin pipe arrangement (13), the housing (12) is fixedly connected, in particular welded, to the housing (21) of the flow sleeve (16), and the flow sleeve is fixedly connected, in particular welded, to the housing (22) of the catalytic converter (3).
8. An exhaust gas system in accordance with any one of the preceding claims, characterised in that the exhaust pipes (5) of the branched exhaust pipe arrangement together with their housing (4) are curved alternately upwardly and downwardly following a wave line in a plan view onto the plane of the exhaust gas inlet openings such that free spaces are formed beside the exhaust gas inlet openings (6) for the access to the screw passages (11) for the fastening of the exhaust gas system to the engine.
9. An exhaust gas system in accordance with any one of the preceding claims, characterised in that a housing (4) is provided which surrounds the branched exhaust pipe arrangement (5) and is fixedly connectable to the engine; and in that the housing (4) is divided at least once in the direction of the connection line of the exhaust gas inlet openings (6), with the parts (4a, b, c) being connected to one another via flexible elements, in particular corrugated bellows (9).
10. An exhaust gas system for multicylinder internal combustion engines in accordance with any one of the preceding claims, characterised in that the housings (4, 12) are each made of sheet metal and include two half-shells (4', 4"; 12', 12"); and/or in that the exhaust pipes (5, 13) are manufactured by internal high pressure shaping; and/or in that the branched exhaust pipe arrangement (5) has four or six exhaust gas inlet openings (6).

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