DE3835841C2 - - Google Patents

Description

The invention relates to an exhaust gas converter for an internal combustion engine machine with a housing and a funnel-shaped exhaust gas inlet neck and a funnel-shaped exhaust outlet and at least one body largely adapted to the shape of the housing for the emission control with between this body and the housing brought heat insulating material and in the exhaust gas inlet and Exhaust outlet are double-skinned and between the a heat-insulating material is attached to both shells and Support elements between two bodies for exhaust gas cleaning and / or between a body for exhaust gas cleaning and the inner shell of the Exhaust inlet or outlet connection.

Here is a device for cleaning under exhaust gas converter Exhaust gases understood, whereby the cleaning is both a process in a catalytically coated body, e.g. B. a monolith, be can pull, as well as cleaning the exhaust gas from soot particles in a suitable body, e.g. B. one provided with longitudinal bores Monoliths. Accordingly, the term body is understood as the component in which the exhaust gas cleaning takes place. In addition to monoliths NEN this can also be known metal carrier bodies or filters.

Generic exhaust gas converters are already known, in which the Body in which the cleaning of the exhaust gas takes place in a housing is stored, in an arrangement for catalytic cleaning according to DE-OS 22 61 663 with the body (monoliths) around the front gripping rings that consist of a hollow ring made of metal foil with a  Core filling made of wire mesh or ceramic fibers are provided. At In this known arrangement, the ring is intended as a support element with a seal function the body even under high thermal loads and under store different thermal expansion of body and housing and the Seal body against exhaust gas flowing around. However, this arrangement has the disadvantage that they radiate the heat of the cat layered monoliths not prevented, so this arrangement does not can be kept at a predetermined temperature. Another Disadvantage of this arrangement is that the grip around the forehead edges of the body to clean part of the passage for the covers the area available and thus the active area is reduced.

Furthermore, according to DE 34 33 938 A1, an arrangement for catalytic purification of exhaust gases with two consecutively arranged known catalytically effective monoliths, in which the both bodies have a distance from each other and in which each of the two bodies is surrounded by heat-insulating material, that encompasses the respective front edges. This arrangement just points if a funnel-shaped double-shell exhaust gas inlet and exhaust gas outlet, with a heat between the two shells Insulation is introduced, the inner shell is in the area of the connection to the housing led to the outside and lies in the end rich the body on the thermal insulation enveloping this end area with the inner shell, while the outer shell ver is bound. However, there is still a risk with this arrangement the erosion of the heat-insulating material due to the pulsating blowing exhaust gas.

To erode the heat-insulating and the storage Preventing materials was eventually found in PA 01 93 072 disclosed a catalytic exhaust gas detoxification device in which in a housing with flue gas inlet and flue gas funnels at a distance several kataly arranged one behind the other to the housing wall  table-coated monoliths are arranged and the space between Monolith and housing with a spring mat (swelling mat) and the exhaust funnels are double-skinned, being between the two Shell heat-insulating material is introduced. This feather mat envelops the monolith over its entire length, whereby in the respective the end sections of the monolith the spring mat in a housing groove provided on the side is guided at a distance from the monoliths and in this area an inner metallic insert for erosion protection is provided. This generic arrangement gives the full Cross-section for the incoming exhaust gas free, but has the disadvantage a cumbersome and time-consuming assembly, which is especially the case with one Mass production such as exhaust gas cleaning systems is significant. Another The disadvantage is the high demand for expensive spring mats.

Many other designs have already been tried a favorable arrangement of the or the catalyst body in an exhaust gas show converter. These constructions show how urgent they are The solution to the problem is to store the catalyst body. So it shows DE-36 26 728 A1 an arrangement in which the monoliths from one continuous to the area of the inlet or outlet funnel reaching source mat is surrounded. With this construction should dig the inside of the inlet funnel into the monolith to to seal against flowing exhaust gas. Are between the monoliths arranged according to this document fixed support or spacer rings. With this arrangement there is a risk of destruction of at least the Entrance area of the monolith.

Monolith bearings in single-shell housings are also known which has been shown, however, that the heat load and the resulting relative movements between monolith and housing cannot be mastered. So the DE-GM 80 19 814 shows a single-shell Housing that is arranged in the space between two in a row Monolith is drawn to the spacer and with by wire knitted monoliths encompassing the end faces of the monoliths  sections. DE-OS 22 13 539 and DE-OS 22 61 663 show in a single-shell housing by a monolith walking, stretching over the entire length and the front edge area mineral fiber mat.

Based on this prior art, the object of the invention based on showing a generic exhaust gas converter, the easy ter is to be assembled and in which the heat-insulating used and the fiber materials used for elastic storage Are protected against erosion with sufficient tightness against the Exhaust gas flowing around the body, the same storage at catalytic coated monoliths and for soot filters (particle filters) for Diesel engines are to be used.

This object is achieved according to the invention in a generic Exhaust gas converter solved by the features that isolate from heat the material existing insert by at least one support element is interrupted, the support element has a core made of ceramic Fibers with a share of 10-50% further, the elasticity heightening fibers and / or a share of 10-50% of a thermal active material suitable for elastic shape adaptation, This core is made of a gas-permeable coating made of high temperature solid material is surrounded and each of the support elements the forehead edge of at least one body serving for exhaust gas cleaning. It has proven to be particularly advantageous that the core of the Support element a share of 10-50% in wire or glass threads having. For the core, the tempe has increased as the elasticity resistant materials as additives to the ceramic fibers glass or wire threads, also in knitted form, proved to be elastic Shape adaptation under the influence of temperature (thermally active substances) Mica, such as B. described in US-PS 39 66 419. That core is used for thermal insulation and to reduce the passage of radiation at high temperatures. It has surprisingly been shown that with this core an increase in the sealing effect with increasing Temperature.  

For the sheathing of the support element is advantageous Wire mesh or wire mesh used. Are also useful Woven quartz glass or knitted quartz glass and according to another Design ceramic mesh or ceramic knitted fabric. The wrapper has the task of discharging the core filling through the pulsating to prevent flowing exhaust gas. This wrapper is not gas tight, but formed as a knitted fabric, fabric or web, in the case of Knitted wire or wire mesh preferably as a single layer or double-layered very thin structure. This can in particular Expansion due to the temperature load the core filling with the Hook the wrapping. This results in spite of the elastic structure the support element has a sufficient seal against the body exhaust gas flowing around. The elasticity of the support element allows the Use of the element for different cross-sectional shapes of the Exhaust gas converter. Exhaust gas converters are round or oval crossways cuts are common, but there are also three in the case of metallic support bodies angular cross-sections known. The wrapping of the elastic support Finally, elementes can also be reinforced and integrated over a section the rigid section. According to a particularly expedient gene further configuration of the support element, this can on a Part of its longitudinal extent is a radially inward-pointing Ab have cut. This section can e.g. B. by an increase times the thickness of the casing can be achieved.

The inventive arrangement of the elastic support element in the Exhaust gas converter takes place on the inlet and outlet side in such a way that at least one of the two end portions of the body about half the length of the Support element is encompassed, the other section in the room protrudes between the two shells of the corresponding exhaust pipe. The annular space between the housing and the body, if not is occupied by the support element, in a known manner with a Thermal insulation material must be filled. This arrangement has opposite the known arrangements for the storage of catalytically coated  Monoliths, in which the storage material (swelling mat) either over the entire area of the converter is arranged or support elements can be used, which embrace the body or flush complete, the advantage that the entry and exit area of Ab gases in / out of the body is enveloped by the support element, furthermore, that the support in the end region or the end regions of the body takes place so that safe storage and good protection against Pulsating exhaust gas flows around the body.

Another useful embodiment results from the fact that at at least two spaced apart one behind the other Bodies the support element at least the distance between the bodies partially covered and the end region of at least one body preferably around the body following downstream. It did proven to be particularly advantageous that the support element on the Part of its length that bridges the distance between the bodies, protrudes at least partially into the section between the bodies. The It can e.g. B. can be achieved in that the exhaust gas converter housing an indentation in the area of the distance between the bodies stored in it less or the same width as the distance between the bodies has, and that the elastic support element hereby when together menbau is pressed somewhat into the distance and at the same time from resists. The spacing function of the elasti cal support element can according to a further advantageous Ausge staltung be achieved in that the radially inwardly projecting Section of the support element has a length that is equal to or is approximately equal to the distance between the bodies.

According to a further advantageous embodiment, there is between two a spacer element is arranged adjacent to the bodies. This is in advantageously designed as a ceramic ring and can be as Correspond to the spacer element in the area of the inlet / outlet funnel be formed according to the contour of the exhaust gas funnel. It is in the Usually a conical ring, but possibly a cylindrical approach  can have. To fix the body in the axial direction there can at the spacer on the side facing the body one or have multiple inward lugs or one inward facing circumferential bead. This spacer is preferred arranged with particularly soft support elements. The Nose or nose or the bead does not have to be at the end of the support be arranged, but can also be on the inner surface of the Spacer be reset. This version with back set stop is provided where the spacer Body towers.

The spacer element preferably has recesses into which the elastic support element can protrude, so that a mutual holding tion is achieved.

Exemplary embodiments are simplified in the figures and shown schematically. However, these are only preferred options application. It shows

Fig. 1 is an exhaust gas converter with the exhaust gas purifying body and serving in the upper and the lower half shown different arrangement of the support elements,

Fig. 2 shows the middle section of an exhaust gas converter with two of the exhaust gas purification serving bodies having support member and spacer member,

Fig. 3 shows an arrangement like Fig. 2 with two different arrangements of the support element and another spacer arrangement.

The exhaust gas converter according to the figures has an exhaust gas inlet nozzle 1 and an exhaust gas outlet nozzle 2 , which can generally consist of a pipe carrying the exhaust gas. The exhaust gas supply determines the shape of the body 4 serving for exhaust gas purification with regard to the inflow cross section. In the case of a single-pipe exhaust gas supply, a body 4 serving for exhaust gas purification is generally used with a round cross section, in other versions with an oval cross section. For exhaust gas converters for the purification of exhaust gas from diesel engines of soot particles, polygonal bodies 4 made of individual layers of corrugated stainless steel are also known in cross section. An inlet funnel 5 connects to the exhaust gas inlet connection 1 and the exhaust gas outlet connection 2 to the outlet funnel 6 . In FIG. 1, the cylindrical, the exhaust gas inlet connection 1 or the exhaust gas outlet connection 2 engages around portion in the inlet and outlet funnel 5 and 6 with the index a. This section is followed by a conical section, designated by the index b, whose end facing the body 4 (index c) can be deformed in such a way that an inboard end section (index d) is also cut by an end section (index d) Index e) follows. Between the body 4 and the Endab section 5 e or 6 e there is a gap 7 , the width of which is dimensioned so that at maximum expansion due to the high exhaust gas temperature, the end section 5 e or 6 e abuts the corresponding end wall of the body 4 . This at the same time provides protection against the exhaust gas flowing around the body 4 and greater stability of the inlet funnel 5 or outlet funnel 6 , so that it can be made from a relatively thin, highly temperature-resistant material. There are further provided in the conical portion 5 b and 6 b of the distribution and reinforcing ribs 8 serving imprinted by means of which a uniform flow of the possible serving the exhaust gas purifier body 4 is effected. Therefore, these ribs 8 can also have a corresponding shape, for. B. drop shape as indicated in the right side of FIG. 1 tet.

The outer shell 9 of the exhaust gas converter preferably consists of two half shells. In the area of the exhaust gas inlet connection 1 and the exhaust outlet connection 2 , the two half-shells - which are firmly connected to one another after assembly by means of welding or flanging (folding) - with the cylindrical section 5 a and 6 a of the funnels 5 and 6 and thus with the connection piece 1 and 2 firmly connected; for the funnels 5 and 6 there is thus the possibility of expansion in the direction of the body 4 . The outer shell 9 essentially follows the contour of a funnel 5 , the body 4 - or in the case of several bodies, the body 4 - and the discharge funnel 6 and has a distance from the inner shell 10 formed from the funnels 5, 6 , a distance between them inner shell 10 is formed in the region of the body 4 by its jacket and, if appropriate, a covering of the body 4 . The - not shown in Fig. 1 - Envelope can consist of a thin, relatively dense ceramic layer when the body 4 is a monolith, or from a metallic shell, for. B. in exhaust gas converter with a metallic support body for the catalytically active surface or in Abgaskonver ter for the cleaning of soot particles from the exhaust gas of diesel engines. When several bodies 4 are arranged one behind the other, the inner shell 10 is formed in the area between the bodies 4 by the spacer element 11 shown in FIGS. 2 and 3 and described there. The outer shell 9 also preferably has radial or axial impressions 12 in the region of the body 4 . The embossments 12 can be directed inwards or outwards and serve to hold the heat-insulating material 13 and to hold the body 4 via the pressure exerted on this material. The radially extending impressions 12 in the form of beads are preferred.

The space between the closed outer shell 9 and the inner shell 10 consisting of individual sections is filled with a heat-insulating material 13 . A functional distinction can be made between the space in the area of the funnels 5, 6 , in which the heat insulation is essential, and the space in the area of the body 4 - or the body 4 - in which, in addition to the heat insulation, a certain storage and holding function of the body 4 is required by the material to be introduced and a certain seal against the exhaust gas flowing around. It can therefore be used for the corresponding sections from different materials.

For example, a expanded mica mat (swelling mat) is preferably used in the area of the body 4 for insulation and support, while ceramic fiber material is preferably used in the area of the funnels 5, 6 .

The front area of the body 4 or the body 4 is excluded from the insert made of heat-insulating material 13 between the inner shell 10 and the outer shell 9 and is replaced by the support element 14 according to the invention. The structure and arrangement of this support element 14 are described below, for example according to FIGS. 1 to 3, but other configurations and corresponding configurations of the support element 14 are also possible.

The support element 14 consists of a core 15 and a sheath 16 . The envelope 16 forms a protective jacket against erosion of the core jacket. It consists e.g. B. preferably provided with recesses sheet metal, wire mesh or knitted fabric or quartz glass fabric or knitted fabric, but can also consist of ceramic fabric or knitted fabric or special glass mats high temperature resistance. The envelope 16 is therefore not gas-tight, but the core filling of the core 15 can get caught in this envelope 16 , so that there is sufficient tightness of the support element 14 .

The core 15 of the support element 14 consists predominantly of ceramic fibers for thermal insulation (obstruction of the passage of radiation at high temperatures) in an embodiment according to the invention combined with glass or wire threads to increase the elasticity and / or with thermally active additives such as expanded mica for elastic adaptation depending on the occurring temperature.

The support element 14 is used by its permanently elastic core 15 and the gas resistant to gas with high flow velocity and strongly changing gas flows to cover 16 to cover and adequately seal gaps due to the different temperatures or materials on the components of the Abgaskonver 3 in operation by Relative movements to each other occur. Here, the existing thermal insulation 13 is to be protected against erosion by the pulsating exhaust gas, without the insulating effect in the region of the gaps being deteriorated. With gap widths in the range from 0.5 to 15 mm, this support element 14 is sufficient on its own; with larger gaps, an annular spacer 11 is arranged between the bodies 4 used for exhaust gas purification, as shown in FIGS. 2 and 3. In particular for mass production, ie large series with the same exhaust gas converter structure, the embodiment of the support element 14 shown in the upper part of FIG. 3 is particularly suitable because it is cheaper and simpler to manufacture and assemble. In this embodiment, the support element 14 has a radially inwardly projecting section 14 a, which corresponds to the distance between the bodies 4 . This section 14 a z. B. be formed as an insert of a ceramic ring within the envelope 16 . The - longer - core 15 is placed on the ceramic ring and both are surrounded by the sheath 16 . But it can also be formed in that the sheath 16 is reinforced in this area, for example by the edge regions of the mat from which the sheath 16 is formed, is double-layered and overlaps when wrapping the core in this area, so that this Section 14 a is four layers. This design has the particular advantage of an elastic spacing in the distance which changes under the influence of temperature, so that the body 4, which is susceptible to breakage, is particularly softly supported.

In FIGS. 2 and 3, the spacing element 11 is shown between the bodies 4. This consists of a ring made of temperature-resistant mate rial, preferably steel with radially inwardly angled end regions and inwardly embossed beads 11 a, into which the support element 14 can be impressed via the impression 12 . The beads 11 a serve at the same time to stiffen the spacer element 11 . On the spacer 11 , as shown in FIG. 3, a cover 17 of the body 4 can be formed on one or both sides, which covers one of the end faces of the body 4 and has slots 17 a.

Fig. 2 shows in the upper section the arrangement of the support element 14 as a replacement for the thermal insulation 13 , in the lower section the arrangement with a thinner layer of the thermal insulation 13th In both cases, the position is securely fixed via the embossment 12 in the outer shell 9 . In Fig. 1, the arrangement of the support element 14 in the transition region between the funnel 5 and 6 and body 4 is Darge. This arrangement can take place over a large area, as shown in the lower region of FIG. 1, or with a shorter support element 14 , as shown in the upper region of FIG. 1, the portion of the support element 14 projecting into the outlet funnel 6 into the deformed end of section 5 c of the inner shell 10 of the funnel 5 presses during assembly and thus forms a flow protection of the body 4 .

In Fig. 3, the arrangement of the cover of the body 4, together with the slots 17 shown 17 a, wherein a one-sided arrangement is shown on the spacer element 11. Of course, both sections 17 and 11 can also be separated. The support element 14 in the lower illustration in FIG. 3 extends only over half the gap between the bodies 4 and is embedded in the thermal insulation 13 and held in the outer shell 9 by the indentation 12 .

Claims (9)

1. Exhaust gas converter for an internal combustion engine with a housing and a funnel-shaped exhaust gas inlet connection and a likewise funnel-shaped exhaust gas outlet connection and at least one body largely adapted to the shape of the housing for exhaust gas supply with heat-insulating material introduced between this body and the housing and double-shelled in the exhaust gas inlet and exhaust outlet connection are formed and a heat-insulating material is introduced between the two shells and support elements between two bodies for exhaust gas purification, and / or between a body for exhaust gas purification and the inner shell of the exhaust gas inlet or outlet connection, characterized by the features:

• - The insert made of heat-insulating material ( 13 ) is interrupted by at least one support element ( 14 ),
• - The support element ( 14 ) has a core ( 15 ) made of ceramic fibers
  • - A share of 10-50% more, increase the elasticity of the fibers and / or
  • - A share of 10-50% of a thermally active material suitable for elastic shape adaptation;
• - This core ( 15 ) is surrounded by a gas-permeable covering ( 16 ) made of high-temperature resistant material,
• - Each of the support elements ( 14 ) covers the front edge at least one of the exhaust gas cleaning body ( 4 ).

2. Exhaust gas converter according to claim 1, characterized in that at least one of the two end regions of the body ( 4 ) of about half the length of the support element ( 14 ) is overlapped, the other portion in the space between the two shells ( 9, 10 ) of the corresponding exhaust connector ( 1, 2 ) protrudes. 3. Exhaust gas converter according to claim 2, characterized in that in at least two successively spaced bodies ( 4 ), the support element ( 14 ) at least partially covers the distance between the bodies and encompasses the end region of at least one body. 4. Exhaust gas converter according to claim 3, characterized in that the support element ( 14 ) on the part of its length which bridges the distance between the bodies, partially protrudes into the section between the bodies ( 4 ). 5. Exhaust gas converter according to claim 4, characterized in that the supporting element ( 14 ) has a radially inwardly projecting portion ( 14 a) on part of its longitudinal extent. 6. Exhaust gas converter according to claim 5, characterized in that the radially inwardly projecting section ( 14 a) has a length which is equal to the distance between the bodies ( 4 ). 7. Exhaust gas converter according to one of claims 1 to 6, characterized in that a distance element ( 11 ) is arranged between two adjacent bodies ( 4 ). 8. Exhaust gas converter according to claim 7, characterized in that the spacer element ( 11 ) is designed as a ceramic ring. 9. Exhaust gas converter according to claim 7 or 8, characterized in that the spacer element has one or more inwardly directed lugs or has an inward bead.