EP0992659B1 - Exhaust pipe element and method for producing an exhaust pipe element - Google Patents

Description

The invention relates to an exhaust gas guide or an exhaust device with at least two supply lines for connection to an internal combustion engine and a wall.

The exhaust gas guide serves as part of an exhaust system of an internal combustion engine for conducting and possibly for the catalytic treatment and purification of exhaust gas. The internal combustion engine may be, for example, a gasoline engine of a passenger car or other road motor vehicle.

Known exhaust manifolds have two or more connectable to an internal combustion engine leads and a common for this collective output, the various pipes consist of tubes with simple metallic walls. Such walls are heated during operation of the internal combustion engine to high, usually at least about 700 ° C amounts temperatures, so that such exhaust manifold and in particular their supply lines give off much heat to their environment. The large heat emitted by radiation, heat conduction and convection causes unwanted heating of temperature sensitive parts and / or spaces located near the exhaust manifold, such as electrical, electronic and / or plastic components, the fuel tank, a spare wheel and / or the passenger compartment. In practice, therefore, it is often necessary to apply heat shields near the exhaust manifolds, which make the production of the motor vehicle more expensive, take up a lot of space and can cause noise problems due to the vibrations generated by the engine.

It is also known to surround the gas-conducting parts of an exhaust manifold or catalyst with a double-walled cooling jacket. The latter has a space through which water is passed through during operation. However, such a cooling jacket also requires a cooling system for circulating and cooling the heated water in the cooling jacket or an enlargement of a primary for cooling the engine cooling system. This increases the space requirements and costs.

US 5,351,483 discloses exhaust manifolds with an exhaust manifold, muffler and catalytic converter. In the variant of an exhaust element shown in FIG. 6, the exhaust manifold and catalyst have a common wall with an outer shell, an inner shell and a layer of insulating material disposed between these shells. The inner shell is directly adjacent to the exhaust passages of the supply lines of the exhaust manifold. These passages open into an expansion chamber. The interior of the expansion chamber is connected through holes in a perforated diffusion plate to a space region adjacent to the catalyst body.

From US 5,351,483 A it is not clear how the multi-layer wall, which encloses the interiors of the supply lines and the catalyst body in cross-section, can be practically produced and assembled and how the diffuser plate and the catalyst body are installed in the space enclosed by the wall interior can. Such a Abgasleitelement is therefore hardly practically produced without considerable changes. Furthermore, the very hot exhaust gases flowing into the supply lines during operation of the engine come into direct contact with the inner shell of the wall. This contact is exacerbated by the fact that the exhaust gas in the supply lines is channeled poorly, so that the exhaust gas flow in the supply lines is likely to be highly turbulent in many places. The inner shell is very hot by the contact with the exhaust gas, so that despite the insulating material layer much heat is released into the environment of the exhaust gas guide and large temperature differences between the inner and the outer shell arise. These temperature differences, in turn, cause large thermal stresses which are likely to cause the joints to somehow interconnect the shells in addition to those in operation as well Heavy vibrations occur occurring vibrations, whereby the durability of the exhaust element is impaired.

EP 0 928 885 A2, published July 14, 1999, discloses exhaust gas guide elements having an exhaust manifold and a catalyst. The exhaust manifold has several supply lines, outer walls and for each supply line in the cross-section of the outer walls enclosed inner line. The exhaust element has two single-layer metallic shells, each of which forms in cross section approximately half of the outer walls of the exhaust manifold and catalyst wall. Between the single-layer, metallic shells and most of the likewise single-layer, metallic inner lines of the supply lines there is an intermediate space containing air and / or exhaust gas. In the catalyst, between the wall forming portions of the shells and the catalyst body, an intermediate layer of a heat-insulating and deformable material is present. The inner leads of the supply lines protect the outer walls of the exhaust manifold when using the Abgasleitelements against direct contact with the very hot, supplied from the engine exhaust. The air and / or exhaust gas containing spaces between the inner pipes and formed by the two shells, outer walls of the exhaust manifold also reduce the heat conduction between the inner pipes and the outer walls. Between the inner pipes and the outer walls, however, can still be a heat transfer by convection and - because of the high temperature of the exhaust gas and the inner pipes - done mainly by radiation, so that the outer walls are still pretty hot. Accordingly, the exhaust element still gives off a relatively large amount of heat to the surroundings adjacent to the exhaust gas guide element and in particular to its exhaust manifold.

FR 2 238 585 A discloses a composite material which consists of a glass fiber fabric arranged between two sheets and in particular serves to form silencer casings. To produce such a two plates of the composite material are formed into half-shells and then joined together at edges. FR 2 238 585 A does not disclose exhaust manifolds. Furthermore, the glass fiber fabric is apparently only quite thin and also has only a low compressive strength. However, to convert a flat composite plate to a relatively small radii of curvature having exhaust manifold large compressive forces must be exerted on the plate, whereby the glass fiber fabric would be compressed very strong. The thickness of the glass fiber fabric in the finished exhaust manifold according to experiments carried out would probably be at most about 20% to 35% of the original thickness and only less than about 1 mm. As a result, the heat output of an exhaust manifold could be reduced only insufficient.

The invention is therefore an object of the invention to provide a Abgasleitelement for conducting and possibly catalytic treatment of exhaust gas, the disadvantages of known exhaust elements and / or exhaust devices with an exhaust manifold and / or catalyst with at least two leads corrects and gives good thermal insulation, but still can be inexpensively manufactured and installed and takes up little space.

This object is achieved according to the invention by an exhaust gas guide with the features of claim 1.

The invention further relates to a method for producing an exhaust gas guide element, wherein the method according to the invention has the features of claim 11.

Advantageous developments of the exhaust element and the method will become apparent from the dependent claims.

The existing according to the invention between the shells of each wall element layer of heat-insulating material gives a good thermal insulation. This ensures that the heat supplied from the exhaust gas largely in the exhaust gas and / or remains in the interior of the exhaust element or the exhaust device. The remaining heat in the exhaust gas is transported by this and derived at least to a large extent together with the exhaust gas into the environment. Each outer shell of the exhaust gas guide element or the exhaust gas device is therefore heated during operation only to a relatively low temperature. Furthermore, the exhaust gas guide gives little heat to its surroundings. Accordingly, it is also not necessary to protect heat-sensitive parts or spaces located in the vicinity of the exhaust-gas guide element by heat shields against the heat emitted by the exhaust-gas guide element or otherwise emitted.

In an advantageous embodiment of the Abgasleitelements this has the supply lines forming the exhaust manifold and another downstream of this arranged, together with this unit forming a catalyst with catalyst means for the catalytic treatment of exhaust gas. The two wall elements of the exhaust manifold can then, for example, in cross-section also completely enclose an interior of the catalyst and in particular the catalyst means. Instead, two additional wall elements can be provided for the catalyst, each having two metallic shells and a layer arranged between them heat insulating material. The two additional wall elements can then completely enclose the catalyst means together in cross-section and, for example, be directly, directly, rigidly and tightly connected to the wall elements belonging to the exhaust manifold. As a result of this design of the exhaust-gas guide element, the catalyst and its connection to the exhaust manifold are also very well thermally isolated. Furthermore, such a unit is particularly economical to produce.

The wall elements are preferably so fixed and substantially rigid and substantially rigidly and at least approximately or fully sealed together that they are self-supporting and together form a self-supporting part of the wall. At least a substantial part of the wall of the exhaust gas guide element can then consist exclusively of the interconnected wall elements. The wall then has to be provided, for example, at the most at the entrance and / or at the exit of the exhaust gas guide element with connecting and / or connecting means in order to connect the exhaust gas guide element to the internal combustion engine and to a part of the exhaust gas system arranged downstream of the exhaust gas guide element. The connecting and / or connecting means may comprise, for example, a common connection flange for all supply lines or at least two connection flanges which are assigned to different supply lines. Furthermore, the wall elements can then form the outermost boundary of the exhaust gas guide element at least for the greater part of the wall.

The wall elements can be designed and connected to each other so that they take up little space. The shells are for example about 0.5 mm to 1 mm thick. The heat-insulating layer is preferably generally at most 10 mm, preferably substantially at least 2 mm, and for example at least approximately 3 mm to at most 5 mm thick in the finished exhaust-gas guide element. The temperatures of the outer shells of the wall elements then amount to, for example, at most about 50% of the measured from 0 ° C temperature of the exhaust gas and / or temperatures on the outer surface of a simple metallic wall with otherwise the same design of the exhaust element or the exhaust device would result.

The thermally insulating material is preferably inorganic, non-combustible and heat-resistant at least up to the operating temperature of the Abgasleitselements and the temperature of the exhaust gas, for example up to at least 800 ° C. Each insulating material layer consists for example of a coherent, reasonably firm, in particular also quite pressure-resistant, microporous plate and / or films. By "microporous" is meant that the layer or plate has pores with sizes of about 1 μm or a few but less than 10 μm or less than 1 μm. Each heat-insulating layer is formed, for example, from an originally particulate material, which consisted at least for the most part of grains and possibly still had fibers and was solidified by pressing and by a thermal treatment and / or a chemical reaction. Each such layer therefore has, for example, more or less firmly adhering grains and possibly still reinforcing fibers. The fiber content is, for example, at most about 10% by weight, so that the layer or plate has at least a large part and, for example, for the most part, a granular structure. The insulating material and in particular its granular components consist, for example, essentially of oxidic substances. The insulating material contains, for example, silica and / or at least one silicate and / or oxide ceramic, namely preferably at least 50% by weight highly dispersed silicic acid. The fibers consist for example of a mineral and / or oxide-ceramic material. Such microporous insulating materials are described, for example, in EP 0 029 227 A and corresponding US 4 985 163 A and available, for example, under the trade name WACKER WDS from Wacker-Chemie GmbH, Munich, Federal Republic of Germany.

To produce the wall, two original flat sheet metal parts can be made into shells for the or each wall element transformed and connected together. In this case, the two sheet metal parts serving to form a pair of shells can be deformed in pairs, at least during a large part of the forming process, together with a layer of heat-insulating material arranged between them. This allows an economical production of the wall.

The forming can be done for example by deep drawing. During forming, a considerable compressive force is exerted on the sheet metal parts or shells and the layer of heat-insulating material arranged between them. The heat-insulating layer is compressed. For example, if the heat-insulating material consists of a pre-consolidated microporous sheet or foil, the thickness of the heat-insulating layer during forming is reduced to less than 50%, usually about 20% to 40%. The thickness of the layer must therefore be relatively smaller prior to forming than the finished exhaust element.

Optionally, each heat-insulating layer instead of a microporous plate or film at least for the most part of a fiber material, for example, a single-layer or multi-layer fabric. The fibers may for example consist of oxide ceramic and / or rock wool, basalt wool, glass wool and / or any other mineral material. However, fiber material is significantly more compressed during forming than a preconsolidated, microporous plate or film, such that the thickness during forming decreases, for example, from about 65% to 80%.

• Fig. 1 eine schematische Schrägansicht eines Verbrennungsmotors mit einem Abgasleitelement, das einen Auspuffkrümmer und einen Katalysator aufweist,
• Fig. 2 das teils im Längsschnitt und teils in Seitenansicht dargestellte Abgasleitelement,
• Fig. 3 einen Querschnitt durch einen Bereich des Katalysators entlang der Linie III-III der Fig. 2 in grösserem Massstab,
• Fig. 4 einen Querschnitt durch das Abgaselement entlang der Linie IV-IV der Fig. 2 in grösserem Massstab,
• Fig. 5 einen Querschnitt durch zwei Blechteile, die zur Bildung der zwei sich in den Figuren 3, 4 unten befindenden Schalen des Abgasleitelements dienen, und eine schematisch dargestellte Umformvorrichtung zum Umformen der Blechteile,
• Fig. 6 einen Querschnitt durch einen Bereich der beiden in Fig. 5 gezeichneten Blechteile bzw. Schalen nach der teilweisen Umformung von diesen und eine schematisch dargestellte Schneidvorrichtung,
• Fig. 7 eine Schneidvorrichtung zum Wegschneiden von Bereichen von Blechteilen, die zur Bildung der sich in den Figuren 3, 4 oben befindenden Schalen bestimmt sind,
• Fig. 8 einen Längsschnitt durch einen Bereich eines anderen Abgasleitelements,
• Fig. 9 eine Schrägansicht von Teilen eines anderen Abgasleitelements, wobei die wärmedämmende Wandung weggelassen wurde,
• Fig. 10 einen vereinfachten Längsschnitt durch das Abgasleitelement gemäss der Fig. 9 mit der wärmedämmenden Wandung und
• Fig. 11 eine Schrägansicht eines Abgasleitelements, das nur einen Auspuffkrümmer aufweist.

The subject invention will be explained in more detail with reference to embodiments illustrated in the drawings. In the drawing shows

• 1 is a schematic oblique view of an internal combustion engine with an exhaust gas guide element having an exhaust manifold and a catalyst,
• 2 shows the exhaust element partly shown in longitudinal section and partly in side view,
• 3 shows a cross section through a region of the catalyst along the line III-III of FIG. 2 on a larger scale,
• 4 shows a cross section through the exhaust element along the line IV-IV of FIG. 2 on a larger scale,
• 5 shows a cross section through two sheet-metal parts, which serve to form the two shells of the exhaust-gas guide element located in FIGS. 3, 4 below, and a schematically illustrated shaping device for shaping the sheet-metal parts,
• 6 shows a cross section through an area of the two sheet metal parts or shells drawn in FIG. 5 after the partial deformation of these and a schematically illustrated cutting device, FIG.
• 7 shows a cutting device for cutting away portions of sheet metal parts which are intended to form the shells located in FIGS. 3, 4 above,
• 8 shows a longitudinal section through a region of another exhaust gas guide element,
• 9 shows an oblique view of parts of another exhaust gas guide element, wherein the heat-insulating wall has been omitted,
• 10 shows a simplified longitudinal section through the exhaust gas guide element according to FIG. 9 with the heat-insulating wall and FIG
• 11 is an oblique view of an exhaust element having only one exhaust manifold.

The partially drawn in Figure 1 and 2 gasoline engine 1 has a motor housing 2, a plurality of cylinders and at least two exhaust gas outlets 3, each with an opening. Each exhaust outlet 3 defines a straight axis 4. The engine has, for example, on both sides three exhaust exits 3 whose axes 4 are parallel to each other, for example in a common plane and inclined downwards away from the engine housing.

An exhaust system has an exhaust device 11, which can be seen in FIGS. 1 to 4, or an exhaust gas guide element 11. The exhaust device or the Abgasleitelement 11 forms an exhaust manifold 12 and a catalyst 13. The exhaust manifold 12 has at least two and namely three in their longitudinal directions at least partially and locally bent leads 15 for connecting the exhaust gas exits 3 with the catalyst 13. The exhaust manifold 12 has Connecting and / or connecting means with a common for all leads 15 connecting flange 17. This has for each supply line 15 an opening.

The catalyst 13 has a casing 21. This has in the flow direction of the exhaust gas in turn an input portion 21a, a main portion 21b, an output portion 21c, and a collar 21d. The main portion 21b is substantially parallel to a straight axis 22 defined by it, and is generally cylindrical and approximately generally oval in cross-section, for example and / or elliptical. The input section 21a connects the three leads 15 to the main section 21b and widens, for example, in at least one longitudinal section towards the main section 21b. The exit portion 21c is generally funnel-shaped and tapers away from the central portion 21b. The collar 21d defines a circular opening. The axis 22 forms with the mutually parallel axes 4, for example, an obtuse angle α.

The exhaust manifold 12 and the housing 21 of the catalytic converter 13 have a common wall with two heat-conducting multilayer and / or composite wall elements 23, 24 connected along the flow path. Each wall element 23, 24 forms approximately half of the wall in cross-section and has one in cross-section continuously connected main portion which forms approximately half of the wall of the housing and a portion of the housing 21 connected to the end portions of the leads 15. Each wall element also has three, finger-shaped portions extending from its main portion to the connection flange 17, which are separated in cross section by free spaces and each associated with one of the leads 15. The two wall elements completely surround an interior in cross sections.

Each multilayer and / or composite wall element 23, 24 has a pair of metallic, one-piece steel shells, namely an outer shell 25, 27 and an inner shell 26, 28, respectively. The two shells 25 belonging to the same wall element, 26 and 27, 28 have, by a gap, separate central portions 25a, 26a, 27a, 28a and edge portions contacting each other along the entire periphery of the shell. The from the inputs of the leads 15 generally in the longitudinal direction along the flow path of the exhaust gas to the outlet of the catalyst extending, outer edge portions of the four shells 25, 26, 27, 28 are designated in Figures 3, 4 with 25b, 26b, 27b, 28b. The central portions 25a, 26a, 27a, 28a are curved in cross-section and bent at least in places. In the two shells 27, 28 located at the bottom in FIGS. 3, 4, the edge sections 27b, 28b project outward away from the middle sections 27a, 28a, are approximately angular and / or linear in cross section. The edge portions 25b, 26b of the two located in Figures 3, 4 above shells 25 and 26 are at most slightly bent relative to the central portion 25a and 26a and project into the formed by the edge portions 28b of the lower inner shells 28 throats. The edge portions 25b of the upper, outer shell 25 contact the edge portions 28b of the lower, inner shell 28. Each finger-shaped portion of a shell is analogous in cross-section to the housing-associated portions of the shell. At the inputs of the leads 15 and at the exit of the catalyst, the edge portions of the shells belonging to the same wall element contact each other in the manner shown in FIG. The edge portions of the various shells abut each other at the points of contact, at least two edge portions each touching each other directly. The edge portions of belonging to the same wall element shells are fixed along the entire circumferences of the shells, substantially rigid and insoluble and tightly connected to each other and partly still with other parts, namely welded. In the generally longitudinally extending, visible in Figures 3, 4 edge portions 25b, 26, 27b, 28b are all four mutually contacting edge portions 25b, 26b, 27b, 28b connected by a joint created in a single welding welding connection 33 together , The same applies to the edge sections between the finger-shaped sections of the shells.

The space between the middle portions 25a, 26a of the shells 25 and 26, respectively, includes an insulating material layer 35. The space between the middle portions 27a, 28a of the two shells 27 and 28, respectively, includes an insulating material layer 36. The insulating material layers 35, 36 essentially complete the said gaps. The insulating material may consist of one of the insulating materials described in the introduction, for example a microporous plate or foil.

The main portion 21b of the housing 21 includes catalyst means 41 for catalytic treatment and purification of the exhaust gas. The catalyst means 41 have, for example, an approximately oval and / or elliptical cross-section, substantially cylindrical catalyst body 42 with an exhaust gas inlet surface 42a and an exhaust gas outlet surface 42b. The surfaces 42a, 42b are planar and perpendicular to the axis 22. The catalyst body has, for example, a ceramic substrate with a plurality of axial passages for the exhaust gas. The passage bounding surfaces of the substrate are provided with coatings consisting mostly of porous alumina and further comprising at least one catalytically active material, such as platinum and iridium.

The main portion 21b of the housing 21 further includes a heat-resistant intermediate layer 43, which is arranged between the lateral surface of the catalyst body 42 and the inner surface of the inner shell 28, the catalyst body encloses in cross-section and holds vibration damping. The intermediate layer 43 consists of a until at least the operating temperature of the catalyst heat-resistant, heat-insulating and, for example, elastically deformable, in particular radially compressible, layered Material. For example, the intermediate layer 43 consists of a mat with inorganic fibers, mineral platelets which are inflated during the first heating, and a binder. However, the intermediate layer could also have at least one layer of wire mesh or wire mesh and a heat insulating filler.

The wall formed by the two wall elements 23, 24 also encloses in cross-section a funnel-shaped collecting and / or input inner wall 45. This is arranged at the transition from the exhaust manifold to the catalyst and is located for the most part within the inlet portion 21a of the housing, but protrudes even in the exhaust manifold belonging to the area of the interior of the Abgasleitelelements inside. The collecting and / or input inner wall 45 encloses a collecting interior in cross section. The downstream end portion of the exhaust manifold and the transition portion thereof to the catalyst thus form a collector or collecting portion of the exhaust gas guide. The collecting and / or inlet inner wall 45 has an end section along the flow path closer to the connecting flange 17, an end section with an inlet opening 45a which is particularly clearly visible in FIG. 4, a central section widening in the direction of flow and at its downstream end a, short substantially cylindrical, in cross-section approximately oval and / or elliptical end portion with an outlet opening. This end portion extends at least approximately to the exhaust gas inlet surface of the catalyst body 42, has an at least approximately aligned with the shell or peripheral surface of the catalyst body outer surface and is at least partially enclosed by the intermediate layer 43. The collecting and / or input inner wall 45 consists of two shells 46, 47 of a metallic material, namely steel. The shells 46, 47 are in cross section arched and bent in places and welded together near their edges.

Each feed line 15 has an inner line 51. This consists of a one-piece, at least locally bent tube made of a metallic material, namely steel. The connection flange 17 has, for example, two flat, abutting plates. The finger-like sections of the four shells 25 to 28, which are assigned to the feed lines, have edge sections projecting into openings of the connection flange 17 and are welded there tightly to one another, to the two plates of the connection flange and to input end sections of the inner lines. The connecting flange 17 is fastened with fastening means 53, which for example have screws, releasably attached to the motor housing 2 and connects the inputs of the leads tightly with the exhaust gas exits 3 of the internal combustion engine. The outlet end portions of the inner conduits 51 facing away from the flange 17 project into the inlet opening 45a of the collecting and / or inlet inner wall 45 side by side so that they at least approximately fill the inlet opening 45a together in cross section, for example in their Longitudinal direction relative to the collecting and / or input inner wall 45 are displaced and at least approximately close connection of the inner leads 51 of the leads 15 with the collecting and / or input inner wall 45 result.

A generally funnel-shaped exit inner wall 55 is located downstream of the catalyst means 41 in the housing 21 and is located for the most part in the exit portion 21c of the housing 21. The exit inner wall 55 has a short, approximately oval in cross-section at its upstream end and / or elliptical end portion, which at least approximately connects to the catalyst body 42, approximately with the shell and / or Peripheral surface has escaping outer surface and is at least partially enclosed by the intermediate layer 43. At this cylindrical end portion, a tapered central portion follows, followed by a short, approximately cylindrical end portion which extends approximately to the downstream end of the housing 21, a circular opening bounded and together with the collar 21d of the housing 21 for all Supply lines common exhaust outlet of the catalyst forms. The exit inner wall 55 consists of a one-piece body of a metallic material, namely steel. A derivative of a tube of a metallic material, namely steel, derivative 57 is sealed and firmly connected to the output inner wall 55 and formed by edge portions of the shells 25, 26, 27, 28 collar 21 d of the housing 21, namely welded. A metallic steel bush 59 has an axial through-hole with an internal thread, projects through holes of the cups 25, 26 and 46 arranged upstream of the catalyst means 41, and is welded tightly to these cups. A lambda probe 60 is screwed into the internal thread of the bush 59 and projects through it into the interior area enclosed by the input inner wall 45. A bushing 61 is welded downstream of the catalyst means 41 in a hole of the conduit 57 and also has an axial through hole with an internal thread into which a projecting into the discharge line 57 lambda probe 62 is screwed. The output of the catalyst 13 can be connected via the discharge line 57 with other parts of an exhaust system, in particular with at least one silencer.

The collecting and / or input inner wall 45 is rigidly connected to the wall by the bushing 59 and, for example, additionally centered by at least one bead or the like and kept limitedly movable or possibly by additional connecting means rigidly connected to the composite wall elements 23, 24. The inner conduits 51 of the leads 15 are separated from the inner shells 26, 28 of the composite wall elements 23, 24 substantially and for the most part - ie apart from their end portions connected to the connecting flange by a continuous gap 65. The intermediate space 65 also separates most of the funnel-shaped collecting and / or input inner wall 45 from the composite wall elements 23, 24. The funnel-shaped exit inner wall 55 is essentially and largely surrounded by a gap 67 from the wall elements 23, 24 separately. The intermediate spaces 65, 67 are substantially hollow and contain air and / or at least approximately stationary exhaust gas.

In the manufacture of the exhaust device or the Abgasleitelements 11 certain, planar, one-piece sheet metal parts are cut to form the shells 25, 26, 27, 28, 46, 47 and the output inner wall 55, for example punched out. The further processing of the sheet metal parts serving to form the two shells 27, 28 located in FIGS. 3 and 4 at the bottom is explained in more detail with reference to FIGS. 5 and 6. The sheet metal parts and their sections are identified by the same reference numbers as the finished shells and their sections. In further processing, for example, the sheet metal part serving to form the outer shell 27 is provided with a shallow recess by pre-forming, in which the still-planar insulating material layer 36 is inserted. Then the still flat sheet metal part 28 is placed on the sheet metal part 27 and used together with the latter in the forming device 71 shown schematically in Fig. 5. This is designed as a thermoforming device and has, for example, a fixed, designed as a die molding tool 72, a retainer 73 and an adjustable mold 74, ie a punch. The edge sections 27b, 28b of the two sheet metal parts 27 and 28 are held for forming between the mold 72 formed as a die and the retainer 73. When the mold 74 serving as a punch is displaced downwardly in the manner indicated by arrows, the sheet metal parts serving to form the trays 27, 28 and the insulating material layer 36 interposed therebetween are simultaneously deformed by deep drawing. The sheet metal parts are plastically deformed and bent. The insulating material layer 36 is - depending on their training - also more or less plastically deformed, bent and compressed.

The middle sections 27a, 28a of the two sheet metal parts or shells 27, 28 receive during forming, i. Deep drawing, drawn in Fig. 6, desired for the finished shells shapes. A cutting device 75 shown schematically in FIG. 6 has two cutting tools 76, 77, of which, for example, the tool 76 has a fixed cutting edge and the tool 77 is designed as a movable knife 77. After forming the central portions 27a, 28a, the unnecessary portions of the edge portions 27b, 28b are cut away with the cutter 75. Thereafter, the remaining edge portions 27b, 28b are bent together in an additional forming step upward or bent so that they receive their final shape.

The originally flat sheet-metal parts for forming the two shells 25, 26 located at the top in FIGS. 3, 4 are analogously reshaped, as was described with reference to FIG. 5 for the shells 27, 28. The sheet-metal parts for the formation of the shells 25, 26 are in this case also, in particular, also shaped to a large extent together with the insulating material layer 35 arranged between them. Thereafter, the held during deep drawing of the die and the holding member edge portions of the sheet metal parts with the arranged in Fig. 7 Cutting device 79 cut as close to the deformed areas of the sheet metal parts. The shells 25, 26 receive their finished shape, so that in these shells no subsequent bending and / or bending of the edge sections is necessary.

When the shells 25, 26, 27, 28 and the insulating material layers 35 and 36 arranged between them are formed, the two pairs of shells according to FIGS. 1 to 4 are assembled and welded together. The welding is carried out for example by means of an electrode, wherein welding material applied and the pairwise adjoining edge sections 25b, 26b, 27b, 28b of all four shells are welded together simultaneously. In this case, the already mentioned weld joint 33 is formed.

The two multilayer and / or composite wall elements 23, 24 can thus be formed in the serial production with relatively few forming operations from originally flat sheet metal parts and originally flat insulating material layers and then connected by a few welding operations. Likewise, the entire exhaust device or the entire exhaust guide 11 may be formed from relatively few originally separate parts and assembled quickly, easily and economically.

When the internal combustion engine 1 generates hot exhaust gas during operation, it flows through the passages delimited by the inner conduits 51 of the supply lines 15 and the interior area widened in the flow direction and / or passage to the exhaust inlet surface 42a of the catalyst body 42 of the input inner wall 45 Catalyst means 41. The funnel-shaped collecting and / or input inner wall 45 serves to collect the exhaust gas coming from the various supply lines and to distribute it from this to the exhaust gas inlet surface 42a of the catalyst body 42. The collecting and / or input inner wall 45 conducts the exhaust gas in general and in particular in the central region ie in the vicinity of the axis 22, parallel to this and approximately perpendicular to the exhaust gas inlet surface 42a against the latter. The exhaust gas then flows through the passages of the catalyst body and is thereby catalytically treated and purified. The exhaust gas flowing out of this at the exhaust gas outlet surface 42b of the catalyst body 36 then flows through the interior of the funnel-shaped outlet inner wall 55, which tapers in the direction of flow, to the outlet 57. The two lambda probes 60 and 62 can control the oxygen content of the exhaust gas upstream or downstream of the catalyst means 41 measure.

The compact design exhaust manifold 11 takes up little space and allows to arrange the catalyst 13 close to the engine 1 and to connect by relatively short leads with this. The insulating material layers 35, 36 of the wall elements 23, 24, the intermediate layer 43 and the air and / or more or less quiescent exhaust gas-containing interstices 65, 67 provide good thermal insulation and isolate the gas-carrying parts of the exhaust manifold and the catalyst thermally against the environment , The good thermal insulation also ensures that the exhaust gas between the engine and the catalyst means is cooled only slightly. This results in a cold start the advantage that the initially having the ambient temperature catalyst means are heated rapidly to the temperature required for an effective catalytic treatment and purification of the exhaust gas.

The hot exhaust gas causes during operation temporary, different heats and expansions of the parts of the exhaust gas guide 11. To enable the training and installation of the gas-carrying parts, which caused by temperature changes, to accommodate different dimensional changes, without generating excessive stresses and damage.

The internal combustion engine 1, which can be seen in part in FIG. 8, in turn has a motor housing 2 and exhaust gas outlets 3 with mutually parallel axes 4. FIG. 8 also shows a part of an exhaust device or exhaust gas element 111 with an exhaust manifold 112 and a catalytic converter 113. The housing 121 of the catalyst defines an axis 122. This forms with the mutually parallel axes 4 again an obtuse angle α. The exhaust manifold 112 and the catalytic converter 113 have two heat-insulating multilayer and / or composite wall elements 123, 124. These include in cross-section inter alia a catalyst body 142 with an exhaust gas inlet surface 142a, an input inner wall 145 and inner pipes 151.

The Abgasleitelement 111 is generally similar to the Abgasleitelement 11, differs from this, however, characterized in that the input portion of the housing 121 and the collecting and / or input inner wall 145 in the drawn axial section are bent and / or angled so that they partially more or less along a straight, parallel to the axes 4 axis. When using the Abgasleitelements 111, the exhaust gas accordingly flows in general and in particular in the central cross-sectional area of the inner wall 151 limited interior space and / or passage more or less parallel to the axes 4 against the exhaust gas inlet surface 142 a. The exhaust gas therefore has a generally in an interior space located slightly upstream of the exhaust gas inlet surface 142a and to a large extent a Flow direction, which is inclined to the exhaust gas inlet surface 142a and forms with this approximately the angle β, which is different from 90 °, namely 90 ° smaller than the angle α.

Figures 9 and 10 show an exhaust device 211 with an exhaust manifold 212 and a catalyst 213. The exhaust manifold has, for example, four leads 215 and a connecting flange 217 which can be releasably secured to a motor housing by fasteners such as screws. The catalyst 213 has a housing 221 which is generally rotationally symmetric about an axis 222 and has an entrance and an exit.

The wall of the exhaust manifold 212 has in the vicinity of the catalyst 213 has a cross-section related main portion and from this away to the flange 217 projecting, in cross-section by gaps from each other, finger-shaped sections. The main portion and the finger-shaped portions of the exhaust manifold wall are formed by two multilayer and / or composite wall elements 223 and 224. Each of these forms approximately half the wall in cross-section and has a pair of metallic shells. Each of these pairs has an outer shell 225 and 227 and an inner shell 226 and 228, respectively. The shells belonging to the same pair have central portions between which an insulating material layer 235 and 236, respectively, is disposed. The wall 224 of the catalyst also has two multilayer and / or composite wall elements 233, 234, each with a pair of shells and an insulating material layer. It should be noted that the four composite wall elements in FIG. 9 have been omitted and drawn only in FIG.

The wall of the catalyst housing formed by the two composite wall elements 233, 234 encloses in cross-section a metallic catalyst inner wall 240. This extends approximately over the entire axial dimension of the composite wall elements 233, 234 and protrudes, for example, at the exit of the catalyst even a little out of the composite wall elements 233, 234 out. The housing 221 and the inner wall 240 have, along the exhaust flow path, a collar approximately parallel to the axis 222, an inlet section widening at least in the longitudinal section drawn in FIG. 10, a cylindrical, approximately circular cross-section or oval main portion, a tapered output portion and a substantially cylindrical collar or neck. The main portion of the catalyst inner wall 240 includes catalyst means 241 having a catalyst body 242. A deformable liner 243 is disposed between the inner wall 240 and the peripheral surface of the catalyst body. The inner wall consists for example of a one-piece sheet metal part or two welded together sheet metal parts.

A metallic collecting and / or input inner wall 245, consisting for example of a one-piece sheet-metal part, is located at least for the most part in the interior space enclosed in cross-section by the composite wall elements 223, 224 of the exhaust manifold and is connected to the inlet of the catalyst inner wall 240 connected, namely, for example, tightly welded. Each feed line 215 has an inner line 251 extending from the connection flange 217 to the collecting and / or input inner wall 245 and at least approximately tight as well as displaceable or rigidly connected thereto. The housing 221 has at its output one between the inner shells of the composite Wall elements 233, 234 and the inner wall 240 protruding sleeve 253rd

The four shells 225, 226, 227, 228 of the composite wall elements 223, 224 and the four shells of the composite wall elements 233, 234 have in cross-section edge portions which are formed analogously and welded together, as in the four shells 25 to 28 according to Figures 1 to 4. The four shells 225 to 228 are welded to the connection flange 217 with this, with each other and with the inner lines 251 of the leads 215. The shells 225 to 228 are at their most downstream edge portions in pairs and directly with the located at the entrance of the housing 221 edge portions of the four shells of the composite wall elements 233, 234 welded. The located at the exit of the housing 221 edge portions of the four shells of the composite wall elements 233, 234 are welded in pairs with each other and with the sleeve 253. A metallic bushing 259 is inserted into the wall of the exhaust manifold 212 near the entrance of the housing 221 of the catalytic converter and welded tightly to a pair of shells of this wall and the collecting and / or inlet inner wall 245. The socket 259 has an internal thread into which a lambda probe 260 is screwed.

The catalyst inner wall 240 is rigidly connected to the composite wall elements 223, 224 by the collection and / or input inner wall 245, bushing 259 and possibly other connections welded thereto, which in turn are rigid with the composite wall elements 233, 234 of the catalyst are connected. The catalyst inner wall 240 is further centered by at least one bead or the like in the housing 221 and held axially displaceable limited. A free air-containing space 265 separates most of the inner conduits 251, the input inner wall 245 and the catalyst inner wall 240 from the walls formed by the composite wall elements 223, 224, 233, 234.

Unless previously stated otherwise, the exhaust gas guide 211 may be similar in construction to the exhaust gas guide 11. Further, the composite wall elements 223, 224, 233, 234 may be fabricated and interconnected in a similar manner as the composite wall elements 23, 24.

In use of the exhaust device 211, the hot exhaust gas flows from the openings of the connecting flange 217 through the inner pipes 251 into the interior of the exhaust collector forming input inner wall 245. The exhaust gas then flows into the inner space extending from the widening inlet portion of the Catalyst inner wall 240 is limited. Subsequently, the exhaust gas flows through the passages of the catalyst body 242 and then through the inner space bounded by the exit portion of the catalyst inner wall 240 to the exit of the catalyst. Thus, the exhaust gas carrying parts are thermally insulated from the environment practically along the whole flow path of the exhaust gas by the heat-insulating composite wall elements 223, 224, 233, 234 and the space 265 containing air. The catalyst means 241 may also be isolated by the intermediate layer 243. Studies have shown that the outer shells 225 and 227 near the junction of the exhaust manifold with the catalyst were heated only to a temperature of about 230 ° C. This temperature is at least or about 300 ° C lower than in an exhaust gas guide, which has only a single-layer, metallic wall, but also an air-containing gap 265 instead of the composite thermal insulating wall elements 223, 224 and otherwise approximately the same as the exhaust element 211 is formed , The free space 265 and the described arrangement of the exhaust gas leading parts also ensure that caused during operation by the heating, different strains of different parts do not cause excessive tension and damage.

In Fig. 11, a part of an exhaust device or a Abgasleitelements 311 is shown, which consists or substantially exclusively of an exhaust manifold 312 and has no catalyst. The exhaust manifold 312 has a plurality of, for example, at least locally bent leads 315, a common for all leads flange 317, a collector or collection section 318 and a Ausgangsflansch 319. The wall of the leads 315 and the collector or collection section 318 consist of two Mehrlagen- and / or Composite wall elements 323, 324. Each of these in turn has a pair of metallic shells and an insulating material layer, as seen in the broken-away portion of FIG. Incidentally, the wall elements 323, 324, for example, similarly formed and connected to each other and with the connection flange 317 as the wall elements 223, 224 shown in Fig. 10. The wall elements 323, 324 are facing away from the connecting flange 317 at the collector or collecting section 318 Ends also sealed and rigidly connected to the output flange 319, namely welded.

The inner space enclosed by the two wall elements 323, 324 contains a collecting inner wall 345 and, for each feed line, an inner line 351. The inner lines 351 are welded to the connecting flange 317 at the input end, similar to the previously described embodiments. The other ends of the inner pipes 351 are connected to the collecting inner wall 345, for example welded, so that the passages of the inner pipes open into the collecting space enclosed by the collecting inner wall. The inner wall 345 and the inner pipes 351 are analogous to those previously described embodiments for the most part by free spaces of the inner shells of the wall elements 323, 324 separated. The inner wall 345, for example, protrudes slightly out of the inner space bounded by the wall elements 323, 324 through the opening of the outlet flange 319 and is separated by a free space from the inner surface of the latter defining the opening of the outlet flange. The exhaust manifold is, for example, still provided with a lambda probe 360, which projects into the collecting interior enclosed by the collecting inner wall 345.

The output of the exhaust manifold formed by the output flange 319 and the protruding end of the collecting inner wall 345, common to all supply lines 315, is connected, for example, via a discharge, not shown, or possibly directly to a catalytic converter.

The exhaust devices and their production can be changed in various ways. For example, features of various described embodiments may be combined with each other. Furthermore, at least some or all of the weld connections may be replaced by edge portions of the shells of the various embodiments by other connections. For example, the edge portions may be connected together at least in part by crimping and / or brazing and / or gluing.

The inner conduits 51 of the embodiment illustrated in FIGS. 1 to 4 may possibly be rigidly connected, for example welded, to the shells of the collecting and / or input inner wall 45. The latter should then preferably be axially displaceable with respect to the composite wall elements 23, 24. If the output end sections the inner conduits 51, on the other hand, are displaceable with respect to the collecting and / or input inner wall 45, as described earlier for the exemplary embodiment according to FIGS. 1 to 4, the two shells 46, 47 can be the input inner wall 45 of FIG 1 to 4 instead of outwardly between the edge portions of the shells 26, 28 projecting and welded with these edge portions. Each of the connection flanges 17, 217, 317 common to all supply lines could be replaced by several separate flanges connected to one or more of the supply lines 15, 215 and 315, respectively. Furthermore, instead of just one catalyst body, the catalyst means could comprise two or more catalyst bodies. Further, the or each catalyst body could be formed from wound or stacked coated sheet metal elements.

In the manufacture of a wall element, the insulating material can be wrapped with a thin plastic shell before being inserted between two metallic shells, held together and protected. This shell can then be decomposed by heating and / or burned after connecting the two shells, so that the plastic shell material is converted into gas and escapes. Further, after the insertion of the insulating material, even before the joint forming, the edge portions of the sheet metal parts serving to form a wall member may be spot-welded or the like in some places to temporarily fix the sheet metal parts and the insulating material.

Claims (16)

1. Exhaust component having at least two inlet lines (15, 215, 315) for connection to an internal combustion engine (1) and a wall, the wall having two metal shells (25, 26, 27, 28, 225, 226, 227, 228) and a layer (35, 36, 235, 236) of heat-insulating material which is located between these shells, the wall being composed of two wall elements (23, 24, 123, 124, 223, 224, 323, 324), each of which has two such shells (25, 26, 27, 28, 225, 226, 227, 228) and a layer (35, 36, 235, 236) of heat-insulating material which is located between these shells, the two wall elements (23, 24, 123, 124, 223, 224, 323, 324) having edge sections (25b, 26b, 27b, 28b) which are connected to one another and together, in cross section, surround interior spaces of all the inlet lines (15, 215, 315), each inlet line (15, 215, 315) having an inner line (51, 151, 251) which, in cross section, is at least partly separated, by a clear intermediate space (65, 265), from the wall elements (23, 24, 123, 124, 223, 224, 233, 234) which surround it in cross section and delimits an exhaust passage, the wall elements (23, 24, 123, 124, 223, 224, 323, 324) together, in cross section, surrounding an inner collection wall (45, 145, 245, 345) which is at least mostly separated, by a clear intermediate space (65), from the wall elements (23, 24, 123, 124, 223, 224, 323, 324) and delimits an inner collection space, to which the inner lines (51, 151, 251) of all the inlet lines (15, 215, 315) are connected, the inner line (51, 151, 251) of each inlet line (15, 215, 315) having an inlet end section which is rigidly connected to the two wall elements (23, 24, 123, 124, 223, 224, 323, 324) and an outlet end section which is connected to the inner collection wall (45, 145, 245, 345) and the outlet end section of each inner line (51, 151, 251) being displaceable with respect to the inner collection wall (45, 145, 245, 345) and/or the latter being displaceable with respect to the wall elements (23, 24, 123, 124, 223, 224, 323, 324).
2. Exhaust component according to Claim 1, characterized in that the layer (35, 36, 235, 236) of heat-insulating material is microporous and has a structure which is grained at least to a substantial extent.
3. Exhaust component according to Claim 1 or 2, characterized in that the layer (35, 36, 235, 236) which is made from heat-insulating material is essentially at least 2 mm and, for example, at least 3 mm thick.
4. Exhaust component according to one of Claims 1 to 3, characterized in that each shell (25, 26, 27, 28, 225, 227, 228) is a single piece, in that the shells (25, 26, 27, 28, 225, 226, 227, 228) which belong to the same wall element (23, 24, 123, 124, 223, 224, 323, 324) are connected to one another essentially along their entire circumference and are designed to be sufficiently strong for them together to be self-supporting, and in that at least a substantial part of the wall comprises exclusively the wall elements (23, 24, 123, 124, 223, 224, 323, 324).
5. Exhaust component according to one of Claims 1 to 4, characterized in that all the shells (25, 26, 27, 28, 225, 226, 227, 228, 325, 326) of the two wall elements (23, 24, 123, 124, 223, 224, 323, 324) which are connected to one another at edge sections (25b, 26b, 27b, 28b) are in contact with one another, at the edge sections (25b, 26b, 27b, 28b), at least in pairs and are joined to one another so that they bear at least approximately tightly together by welding and/or brazing and/or adhesive bonding and/or flanging.
6. Exhaust component according to one of Claims 1 to 5, characterized in that the wall elements (23, 24, 123, 124, 223, 224, 323, 324), at least in most of the wall, form the outer limit of the exhaust component.
7. Exhaust component according to one of Claims 1 to 6, characterized in that the two wall elements (23, 24, 123, 124, 223, 224, 323, 324) which together surround interior spaces of the inlet lines (15, 215, 315) together, in cross section, also surround at least a substantial part of the inner collection space.
8. Exhaust component according to one of Claims 1 to 7, characterized in that, in addition it has a catalytic converter (13, 113, 213) containing catalyst means (41, 42) for the catalytic treatment of exhaust gas, and in that the two said wall elements (23, 24, 123, 124, 223, 224) or two additional wall elements (233, 234) which are connected thereto, each with a pair of metal shells and a layer of heat-insulating material which is provided between these shells, surround the catalyst means (41, 42) in cross section.
9. Exhaust component according to Claim 8, characterized in that the two additional wall elements (233, 234) are directly and rigidly connected to the wall elements (223, 224) which surround the interior spaces of the inlet lines (215) of the exhaust manifold (212).
10. Exhaust component according to one of Claims 1 to 9, characterized in that the wall elements (23, 24, 123, 223, 224, 323, 324), which together surround interior spaces of the inlet lines (15, 215, 315), have finger-shaped sections which are separated from one another by intermediate spaces and are each assigned to one of the inlet lines (15, 215, 315).
11. Method for producing an exhaust component according to one of Claims 1 to 10, two sheet-metal parts being provided for each wall element (23, 24, 123, 124, 223, 224, 323), each of which sheet-metal parts serves to form one of the two shells (25, 26, 27, 28, 225, 226, 227, 228, 325, 326), a layer (35, 36, 235, 236) of heat-insulating material being arranged between the two sheet-metal parts, and the two sheet-metal parts and the layer (35, 36, 235, 236) arranged between them then being deformed together in such a manner that the two wall elements (23, 24, 123, 124, 223, 224, 323) together, in cross section, surround interior spaces and inner lines (51, 151, 251) of the inlet lines (15, 215, 315), and the shells (25, 26, 27, 28, 225, 226, 227, 228, 325, 326) being connected to one another after their formation by forming the sheet-metal parts at edge sections (25b, 26b, 27b, 28b).
12. Method according to Claim 11, characterized in that each layer (35, 36, 235, 236) of heat-insulating material, during forming of the sheet-metal parts and the layer (35, 36, 235, 236) arranged between them, is compressed in such a manner that the layer (35, 36, 235, 236), in the finished exhaust component, is essentially at least 2 mm and, for example, at least 3 mm thick.
13. Method according to Claim 11 or 12, characterized in that two pairs of shells (25, 26, 27, 28, 225, 226, 227, 228), with layers (35, 36, 235, 236) arranged between them, are shaped so as to form two wall elements (23, 24, 123, 124, 223, 224, 324, 325) which, in cross section, together surround the interior spaces of the inlet lines (15, 215, 315), and in that, after forming of the shells (25, 26, 27, 28, 225, 226, 227, 228), edge sections (25b, 26b, 27b, 28b) of all the shells (25, 26, 27, 28, 225, 226, 227, 228) of the two wall elements (23, 34, 123, 124, 223, 224, 324, 325) are at the same time joined together by welding and/or brazing and/or adhesive bonding and/or flanging.
14. Method according to one of Claims 11 to 13, characterized in that the sheet-metal parts which are provided for forming each wall element (23, 24, 123, 124, 223, 224, 323, 324) are originally planar, in that one of the two planar sheet-metal parts intended to form a wall element (23, 24, 123, 124, 223, 224, 323, 324) is provided with a shallow recess by preliminary shaping, into which recess a still planar layer (35, 36, 235, 236) of the heat-insulating material is placed, and in that the two sheet-metal parts and the layer (35, 36, 235, 236) of heat-insulating material arranged between them are then deformed jointly.
15. Method according to one of Claims 11 to 14, characterized in that the joint deforming of the two sheet-metal parts and the layer (35, 36, 235, 236) of heat-insulating material arranged between them is effected by deep-drawing.
16. Method according to one of Claims 11 to 15, characterized in that the layer (35, 36, 235, 236) of the heat-insulating material is formed from a microporous plate or sheet which contains silica and/or at least one silicate and/or oxide ceramic and which at least to a large extent has a granular structure and, for example, still contains at most 10% by weight of fibres.

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