DE3835841A1 - Exhaust converter for an internal combustion engine - Google Patents

Abstract

An exhaust converter for exhaust emission control of an internal combustion engine is set forth, in which the body or bodies serving for exhaust emission control are mounted in a support ring, which comprises a core filling of ceramic fibres with an inlay of elasticity-increasing or thermally active substances and a non-gas tight casing. The said support element is arranged in the end areas of the bodies, it being possible to provide a spacer ring between the bodies and in the inlet/outlet area of the bodies.

Description

The invention relates to an exhaust gas converter for an internal combustion engine machine with a housing and a funnel-shaped exhaust gas outlet connection and a funnel-shaped exhaust step connection and at least one of the shape of the housing wide body adapted for exhaust gas cleaning with between This body and the housing introduced heat insulating Material and at the exhaust gas inlet and exhaust port are double-skin, the inner shell einsei tig has a sliding seat and between the two shells a heat insulating material is attached.

Here is a device for cleaning under exhaust gas converter of exhaust gases understood, the cleaning both on one Process in a catalytically coated body, e.g. B. one Monoliths can relate to the purification of the exhaust gas of soot particles in a suitable body, e.g. B. one with Monoliths provided with longitudinal bores. That is also the case  Concept body understood as the component in which the exhaust gas purification delivery takes place. In addition to monoliths, this can also be known metal be carrier body or filter candles.

Generic exhaust gas converters are already known at wel Chen the body in which the exhaust gas is cleaned in a housing is mounted, in an arrangement for catalytic cleaning according to DE-OS 22 61 663 in the body (Monoliths) rings encompassing the end face, which consist of a hollow ring made of metal foil with a core filling made of wire mesh or Ceramic fibers are provided. In this known arrangement the ring as a support element with a sealing function also supports the body high thermal loads and different thermal expansion store body and housing safely and flow around the body Sealing exhaust gas. However, this arrangement has the disadvantage that they radiate a warmth of the catalytically coated Monoliths not prevented, so this arrangement is not on the predetermined temperature can be maintained. Another after part of this arrangement is that the embracing of Front edges of the body part of the passage of the covers the surface available for cleaning exhaust gas and so that the active area is reduced. Furthermore, after the DE-OS 34 33 938 an arrangement for the catalytic cleaning of Exhaust gases with two catalytically active series coated monolith known, in which the two bodies one Distance from each other and at which each of the two Body is surrounded by heat insulating material that the ever around the front edges. This arrangement also points a funnel-shaped double-shell exhaust gas inlet and exhaust gas outlet, with a between the two shells Thermal insulation is introduced, the inner shell is in each case led to the outside in the area of the connection to the housing and  lies in the end area of the body on which this end area envelops heat insulation with the inner shell while the Outer shell is connected to the housing. With this arrangement however, there is still a risk of erosion of the thermal iso the pulsating exhaust gas.

To prevent erosion of the heat insulating and the storage Preventing material was finally in the EURO-A 01 93 072 opened a catalytic exhaust gas detoxification device beard, in which in a housing with exhaust gas inlet and exhaust discharge funnel at a distance from the housing wall several at a distance Catalytic coated monoliths arranged one behind the other are arranged and the space between the monolith and the housing a spring mat (swelling mat) and the exhaust gas funnel double lig are formed, heat between the two shells insulating material is introduced. This feather mat envelops the monolith over its entire length, whereby in the respective end sections of the monolith the spring mat in a ge groove provided on the housing side at a distance from the monoliths leads and in this area an inner metallic insert is provided for erosion protection. This generic arrangement voltage gives the full cross section for the incoming exhaust gas free, but has the disadvantage of being cumbersome and expensive assembly, which is particularly the case with a mass product such as exhaust gas cleaning systems is considerable. Another disadvantage is the high one Need for expensive feather mat.

Based on this prior art, the invention lies The task is based on a generic exhaust gas converter show that is easier to assemble and in which the ver applied heat-insulating and elastic storage serving fiber materials are protected against erosion  a sufficient tightness against the body flowing Ab gas, the same arrangement with catalytically coated Monoliths as well as soot filters (particle filters) for diesel motors can be used.

This object is achieved according to the invention in a generic Exhaust gas converter solved in that at least a section of the insert made of heat-insulating material by means of an Ab support element is replaced, which is a core of ceramic fibers with a share of 10-50% of others, he elasticity high temperature-resistant fibers and / or a share of 10- 50% of a thermally active, for elastic shape adjustment suitable material as well as a non-gastight covering made of high temperature-resistant material. It turned out to be special proved advantageous that the core of the support element one Contains 10-50% of wire or glass threads. For the Core have temperature-resistant as elasticity increasing Fabrics as additives to the ceramic fibers glass or Wire threads, also in knitted form, have been shown to be elastic Shape adaptation under the influence of temperature (thermally active substances) Mica, such as B. described in US-PS 39 66 419. This The core is used for thermal insulation, to prevent radiation continuity at high temperatures. It has been more surprising Wise shown that with this core an increase in the sealing effect takes place with increasing temperature.

For the sheathing of the support element according to the invention in advantageously used wire mesh or wire mesh. It is also expedient to use quartz glass or quartz glass knitted and according to a further practical embodiment Ceramic fabric or knitted ceramic. The wrapper has the opening handing out a discharge of 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 the wire mesh or wire mesh preferably as a single layer or double-layered and therefore very thin structure. This can especially when expanding due to the temperature load hook the core filling with the covering. This results in despite the elastic structure of the support element sufficient sealing against the exhaust gas flowing around the body. The Elasticity of the support element allows the use of the Ele mentes for different cross-sectional shapes of the exhaust gas converters ters. Exhaust gas converters are round and oval cross sections usual, but also triangular ones with metallic carrier bodies Cross sections known. The wrapping of the elastic support element Finally, mentes can also be reinforced over a section and be rigid in the reinforced section. According to one particularly expedient further configuration of the support element can this radially follows on part of its longitudinal extent have interior facing section. This section can e.g. B. who achieved by multiplying the thickness of the envelope the, but also by a suitable insert from z. B. high temperature raturfestem metal or ceramic material.

The arrangement of the elastic support element according to the invention in the exhaust gas converter takes place such that at least one of the two end regions of the body of about half the length of the ab Support element is encompassed, the other section in the Space between the two shells of the corresponding exhaust pipe protrudes. The annular space between the housing and the body, as far as it is not occupied by the support element, in a known manner be filled with a thermal insulation material. This arrangement compared to the known arrangements for storage catalytically coated monoliths, in which the bearing material (swelling mat)  is arranged over the entire area of the converter or support elements can be used that brow the body grip or close flush, the advantage that the or exit area of the exhaust gas in / out of the body from the exhaust gas support element is encased that the support in the end region or the end regions of the body, so that a secure position tion is achieved, and that good protection against flow pulsating exhaust gas is reached in the body.

Another useful embodiment results from the fact that at least two in a row at a distance from each other arranged the support element the distance between the bodies Bodies at least partially covered and the end area min at least one body, preferably the downstream body pers, embraces. It has proven to be particularly advantageous indicated that the support element on the part of its length, the bridging the distance between the bodies, at least partially protrudes wisely into the section between the bodies. This can e.g. B. can be achieved in that the exhaust gas converter housing in Area of the distance of the bodies stored in it an impression less or the same width as the distance between has the bodies, and that the elastic support element here by pressing something into the distance during assembly and so acts at the same time keeping a distance. The at the same time spaced Tende function of the elastic support element can according to a further particularly advantageous embodiment be achieved that the radially inwardly projecting section of the support element has a length that is equal to or at is approximately equal to the distance between the bodies.

According to a further particularly advantageous embodiment, in the area in which the support element projects above the body  Spacer arranged. This is advantageous as Ceramic ring formed and according to a continuation as a distance element in the area of the inlet / outlet funnel accordingly the contour of the exhaust gas funnel. This is usually the case a conical ring, but possibly a cylindrical approach can have. For fixing the body in the axial direction can the spacer on the side facing the body have one or more inwardly directed lugs or an inward circumferential bead. This distance element is preferably used with a particularly soft Ab support elements arranged. The nose or noses or the bulge does not have to be arranged at the end of the support element, but can also return to the inner surface of the spacer be set. This version with a reset stop will provided where the spacer element faces the body towered over.

The spacer element preferably has recesses into which the elastic support element can protrude, so that a counter term bracket is reached.

Exemplary embodiments are combined in the attached figures shown in a fold and schematic. However, these only apply preferred application possibilities. It shows:

Fig. 1 shows an exhaust gas converter with an exhaust gas cleaning body and in the upper and the lower half differently shown Anord voltage of the support elements

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

Fig. 3 shows an arrangement as shown in FIG. 2 with two different arrangements of the support element and other spacer arrangement.

The exhaust gas converter according to the figures has an exhaust gas inlet 1 and an exhaust gas outlet 2 , which can generally consist of a tube carrying the exhaust gas. This exhaust gas supply determines the shape of the body 4 used for exhaust gas purification with respect to the inflow cross section. In the case of single-pipe exhaust gas supply, a body 4 with a round cross section is generally used, in other versions with an oval cross section. For in particular exhaust gas converters for cleaning exhaust gas from diesel engines from soot particles, polygonal bodies made of individual layers of corrugated stainless steel are also known in cross section. At the exhaust pipe 1 closes an inlet funnel 5 and from the funnel 6, the exhaust pipe 2nd In Fig. 1 the cylindri cal, the exhaust pipe 1 or 2 surrounding portion of the funnel 5 or 6 is marked 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 inwardly directed bead (index d ) also has an inward endab cut (index e ) follows. Between the body 4 and the end section 5 e or 6 e there is a gap 7 , the width of which is dimensioned such 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 also provides protection against the exhaust gas flowing around the body 4 and greater stability of the funnel 5 or 6 , so that it can be made of relatively thin, high-temperature-resistant material. There are also embossed in the conical section 5 b and 6 b distribution and stiffening ribs 8 , by means of which the most uniform possible flow to the exhaust gas cleaning body 4 is effected. Therefore, these ribs 8 can also have a corresponding shape, for. B. teardrop shape as indicated in the right side of FIG. 1.

The outer shell 9 of the exhaust gas converter 3 preferably consists of two half shells. In the area of the exhaust gas inlet pipe 1 and the exhaust gas outlet pipe 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 pipe 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 the inlet funnel 5 , the body 4 - or, in the case of several bodies, the body 4 - and the outlet funnel 6 and is at a distance from the inner shell 10 formed from the funnels 5 , 6 , this 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 - cladding can consist of a thin, dense ceramic layer if the body 4 is a monolith, or of a metallic shell, for. B. in exhaust gas converter with a metallic support body for the catalytically active surface or in exhaust gas converter 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 by the spacer element 11 shown in FIGS. 2 and 3 and described there. The outer shell 9 also preferably has 4 radial or axial impressions 12 in the region of the body. These impressions 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 radial impressions 12 (as beads) are preferred.

The space between the closed outer shell 9 and the inner shell 10 consisting of individual segments 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 positioning and holding function of the body 4 due to the material to be introduced and a certain seal against the flowing exhaust gas. Different materials can therefore be used for the corresponding sections.

For example, an expanded mica mat is preferably used for insulation and mounting in the area of the body 4 , while ceramic fiber material is preferably used in the area of the funnels 5 , 6 .

From this insert made of thermally insulating material 13 between the inner shell 10 and the outer shell 9 of the front area of the body 4 and the body 4 is excluded or reduced in density deposits and replaced by the fiction, modern supporting fourteenth Structure and arrangement of this support element 14 are described below, for example, according to FIGS. 1 to 3, although other configurations and corresponding configurations of the support element 14 are also possible.

The support element 14 consists of a core 15 and an envelope 16 . The envelope 16 forms a protective jacket against erosion of the core material. It consists e.g. B. from preferably provided with recesses sheet, 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 high temperature resistance. The sheath 16 is therefore not itself gas-tight, rather the core filling of the core 15 can get caught in this sheath 16 , so that there is sufficient tightness.

The core 15 consists predominantly of ceramic fibers for heat insulation (obstruction of the radiation passage 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 against gas with high flow velocity and strongly changing highly resistant sheath 16 to cover and adequately seal gaps that share due to the different temperatures or materials on the construction of the exhaust gas converter 3 in operation by relative movements occur to each other. 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 impaired. In the case of gap widths in the range from 0.5 to 15 mm, this supporting element 14 is sufficient on its own; in the case of larger gaps, a spacer ring 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 gap width 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 . However, it can also be formed in that the covering 16 is reinforced in this area, for example in that the edge areas of the mat from which the covering 16 is formed are double-layered and still overlap in this area when the core is covered, so that the latter Section 14 a is four layers. This embodiment has the particular advantage of an elastic spacing in the gap which changes under the influence of temperature, so that the body 4, which is susceptible to breakage, is supported in a particularly soft manner.

In FIGS. 2 and 3, the spacing element 11 is between the pern Kör 4 is shown. This consists of a ring made of temperature-resistant material, preferably steel with radially inwardly angled end regions and radially inwardly embossed beads 11 a , into which the support element 14 can be embossed via the embossing 12 . The beads 11 a serve the stiffening of the spacer 11 at the same time. On the spacer 11 , as shown in FIG. 3, a body cover 17 can be formed on one or both sides, which engages around 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 Abolzenelemen tes 14 in place of the heat insulation 13 , in the lower section the arrangement with a thinner layer of heat insulation 13th In both cases, the position is securely fixed via the embossing 12 in the outer shell 9 . In Fig. 1, the arrangement of the supporting element 14 in the transition region between the hopper 5 and 6 and the body 4 is shown. This arrangement can take place over a large area, as shown in the lower region of FIG. 1, or with a shorter element 14 , as shown in the upper region of FIG. 1, the funnel-side section of the support element 14 being in the deformed end of section 5 c the inner shell 10 of the funnel 5 , 6 presses during assembly and thus forms a current-side protection of the body 4 .

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

Claims (14)

1. Exhaust gas converter for an internal combustion engine with a housing and a funnel-shaped exhaust gas inlet connector and a likewise funnel-shaped exhaust gas outlet connector and at least one body largely adapted to the shape of the housing for exhaust gas purification with heat-insulating material introduced between this body and the housing and at the exhaust gas inlet and exhaust outlet are double-shelled and a heat-insulating material is introduced between the two shells, characterized in that at least a portion of the insert made of heat-insulating material ( 13 ) is replaced by a support element ( 14 ) which has a body ( 4 ) made of ceramic fibers with a Share of 10-50% of other high-temperature-resistant fibers that increase the elasticity and / or share of 10-50% of a thermally active substance suitable for elastic shape adaptation, as well as a non-gas-tight covering ( 16 ) has temperature-resistant material. 2. Exhaust gas converter according to claim 1, characterized in that the body ( 4 ) of the support element ( 14 ) has a proportion of 10-50% of wire or glass threads. 3. Exhaust gas converter according to claim 1 or 2, characterized in that the covering ( 16 ) of the support element ( 14 ) is formed from wire mesh or wire mesh. 4. Exhaust gas converter according to claim 1 or 2, characterized in that the sheath ( 16 ) of the support element ( 14 ) is formed from quartz glass or quartz glass. 5. Exhaust gas converter according to claim 1 or 2, characterized in that the sheath ( 16 ) of the support element ( 14 ) is made of ceramic fabric or ceramic knitted fabric. 6. Exhaust gas converter according to one of claims 1 to 5, 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 encompassed, the other portion in the space between the two shells ( 9 , 10 ) of the corresponding exhaust nozzle ( 1 , 2 ) protrudes. 7. Exhaust gas converter according to claim 6, characterized in that with 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. 8. Exhaust gas converter according to claim 7, 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 ). 9. Exhaust gas converter according to claim 8, characterized in that the support element ( 14 ) has a radially inwardly projecting portion ( 14 a ) on part of its longitudinal extent. 10. Exhaust gas converter according to claim 9, characterized in that the radially inwardly projecting section ( 14 a ) has a length which is equal to the distance between the bodies ( 4 ). 11. Exhaust gas converter according to one of claims 6 to 8, characterized in that in the area in which the supporting element ( 14 ) projects beyond the body ( 4 ), a spacer element ( 11 ) is arranged. 12. Exhaust gas converter according to claim 11, characterized in that the spacer element ( 11 ) is designed as a ceramic ring. 13. Exhaust gas converter according to claim 11 or 12, characterized in net that the spacer according to the contour of the Ab trained as a judge. 14. Exhaust gas converter according to claim 11, 12 or 13, characterized records that the spacer one or more inwards directed noses or an inward bead points.