EP0929738B1 - Honeycombed body with heat insulation, preferably for an exhaust gas catalyzer - Google Patents

Abstract

The invention concerns a honeycombed body with a plurality of honeycombs and heat insulation (43) comprising a plurality of stacked and/or wound insulating metal layers (4; 34) which support one another owing to microstructures (5) formed in the insulating metal sheets (34), such that spaces are produced between the latter. The microstructures (5) are between 10 νm and 250 νm high. In this way, the heat losses from the honeycombed body to the environment are only low.

Description

The present invention relates to a honeycomb body with a plurality of Honeycomb according to the features of the preamble of claim 1. Ein Such a honeycomb body is known from EP-A-0 229 352.

A coating applied to the walls of the honeycomb catalytic material enables the conversion of exhaust gases from internal combustion engines.

In WO 90/08249 and in WO 96/09892 honeycomb bodies are included Macrostructures described that determine the honeycomb shape. The honeycomb body also have microstructures that block the flow of water through the Affect honeycomb flowing exhaust.

The honeycomb walls are made of metal, for example. One way of Production of honeycomb bodies with such honeycomb walls involves soldering. Suitable types of soldering are, for example, from WO 89/07488 known.

It is known from EP 0 229 352 to use thermal radiation protection. The thermal radiation protection consists of one or more sheet layers, which are arranged outside a casing tube. In doing so uses the same sheet metal layers as the honeycomb structure within the Form the casing tube.

In automotive construction in particular, there are increasing demands the properties of an exhaust gas catalyst. In the course of ever stricter Above all, the cold start and restart behavior must constantly comply with emissions standards be improved. When restarting an engine after a standstill it is important that the honeycomb body of the catalyst is another has the highest possible temperature. WO 96/07021 describes one catalytic reactor for the conversion of exhaust gases, both within and also has thermal insulation outside a jacket. As Examples of such insulation are an air gap and an insulating mat called.

In the prior art mentioned, the insulating effect is caused by air or achieved by a solid insulating material. There is still air a lower thermal conductivity than known solid insulation materials, they however, only minimally hinders the heat transport by radiation. Several sheet metal layers, as suggested in WO 96/07021 on the other hand reduce heat radiation considerably. However form the sheet layers through their contact points thermal bridges with the consequence that in turn a significant heat transfer through heat conduction occur can.

The present invention has for its object a honeycomb body to develop so that he has little heat loss to the environment.

This object is achieved by a honeycomb body with the Features solved, which are specified in claim 1. Advantageous further training are the subject of the dependent claims.

The honeycomb body according to the invention is characterized in that it has a Thermal insulation with a plurality of stacked and / or wound Has insulating sheet layers, which are mutually through in the insulating sheet layers support trained microstructures so that between the insulating sheet layers There are gaps. The microstructures have roughly a height of 15 µm to 250 µm. They are much lower than the structures known from EP 0 229 352 for the formation of exhaust gas flowable honeycomb channels. Microstructures of this height are out WO 96/09892 known in which they are laminar for thorough mixing flowing exhaust gas in the honeycomb-like channels have been proposed are. In a honeycomb body according to the invention, the properties such microstructures but used in a completely different way. Because of her low height, it is possible to have a variety of insulation sheet layers small space to be stacked on top of each other, thereby increasing the heat transfer significantly reduced due to heat radiation through the stack becomes. Since the reduction is a good approximation of the number of Insulation sheet layers depends on the state of the art space can be saved or a higher insulation effect can be achieved.

However, the greater stack density has another advantage. By suitable Formation of microstructures, e.g. so that this narrow sharp-edged Have ridges, the contact surface between each considerably reduce two layers of insulating sheet. This means that heat can also be transported be significantly reduced due to heat conduction.

Particularly effective around the honeycomb body with its multitude of honeycombs To protect against heat loss, it is beneficial if the insulating sheet layers surround the honeycombs as closed as possible. With honeycomb bodies for the Use as an exhaust gas catalyst carrier are naturally openings for the Keep entry and exit of exhaust gas clear. The type according to the invention In a special embodiment, thermal insulation is also used Protection of heat-sensitive objects in the vicinity of a honeycomb body used. The thermal insulation only partially surrounds the honeycombs, so that a thermal insulation effect in, seen from the honeycomb, limited solid angle ranges is achieved.

In a preferred embodiment of a honeycomb body according to the invention are the insulating sheet layers of the thermal insulation at least partially with each other technically connected, preferably soldered. One advantage is that thus achievable mechanical stability of the thermal insulation.

In an advantageous embodiment, the honeycombs have metallic honeycomb walls on. In design variants, which also include the honeycomb Adjacent insulation sheet layers are metallic, solder connections can Honeycombs with each other and from honeycombs with insulating sheet layers at the same time the same soldering process.

Alternatively, other materials, such as ceramic, used for the honeycomb walls, or combined different materials. A special design is achieved by using a green ceramic with a variety of honeycomb insulation sheet layers and then the ceramic is fired. In a variant of it keep the insulating sheet layers on the green ceramic due to their microstructures firmly, as these are pressed into the green ceramic.

In the case of metallic honeycomb walls, high demands are placed on them Corrosion resistance provided. A honeycomb body according to the invention, which in suitably equipped with catalytically active material themselves for converting exhaust gases from an internal combustion engine, in particular of an Otto engine. The exhaust gas temperature of such engines is typically above 800 ° C. A honeycomb body for this purpose must Corrosion processes at these temperatures over thousands of operating hours withstand. On the other hand, there is no heat insulation to make the same demands. The thermal insulation is not that high Exposed to temperatures like the honeycomb walls. With good insulation reach at most similar insulating sheet layers to the honeycomb walls high temperatures. In a preferred embodiment of an inventive The thermal insulation also does not come into contact with the honeycomb body with corrosive gases, in particular in an embodiment in which the Thermal insulation against any gas entry into the gaps is completed is.

In a further embodiment, a honeycomb body has a tubular casing, there are honeycombs in the pipe interior. Such an embodiment is out For reasons of mechanical stability, but also for technical reasons Reasons advantageous. There are various types of such a honeycomb Design variants. One has thermal insulation as described above also inside the pipe. Other variants lie instead or in addition, such thermal insulation outside the jacket tube. Here, for example, a particularly thick outermost layer of insulating sheet metal offers or a second, outer casing tube protection against mechanical Damage. Connections are used for variants with metallic jacket pipes at least advantageously between heat insulation and the casing pipes partially soldered.

The insulating sheet layers of the thermal insulation are in a different embodiment Parts of a continuous sheet metal strip that is spirally wound. In a special variant, the thermal insulation has exactly two metal strips on, the microstructures being formed in at least one. The two metal strips are in a spiral winding with each other devoured. Such a winding can be produced, for example, by that the two metal strips are first placed on top of each other then one end to each other and / or to another part of the honeycomb body, e.g. attached to a casing tube and then wound. Other variants use more than two metal strips. Spiral windings are advantageous, among other things, because they are particularly easy to manufacture. But it can also be ring-shaped in itself closed insulation sheet layers are used. For special purposes, while maintaining the principle of construction, completely different forms of Thermal insulation possible. To single sensitive objects outside To protect the honeycomb body from heat radiation, for example a stack of a limited part of the surface of the honeycomb body slightly curved layers of insulating sheet arranged.

In a further embodiment, the honeycombs are at least partially heatable. Due to the thermal insulation, the heated area can be without substantial heat losses quickly to a desired operating temperature to be brought. The thermal insulation helps to conserve the energy source, e.g. a battery of a motor vehicle.

In various configurations, the thermal insulation has end faces, where edges of a plurality of the insulating sheet layers lie. Will one The face of such a honeycomb body, for example, has air flowing against it, then an undesirable cooling effect by an air flow through the Interstices occur. In a low-priced further education, the Insulation sheet layers therefore close to the face or faces at least partially interconnected so that an air flow, or a different gas flow, between the gaps and the environment of the Thermal insulation is obstructed or blocked. For example, the insulation sheet layers soldered to each other near the front, they are on the end face with a filling compound or it is an additional End piece attached to the front.

The efficiency of thermal insulation is increased in that the gaps All or part of the air between the insulating sheet layers and are evacuated. Except for the decrease in total thermal conductivity is therefore also the entry of corrosive gases into the Prevents thermal insulation.

The heat radiation within the heat insulation and / or the heat radiation from the honeycomb body to the outside is further reduced by at least part of the insulating sheet layers of the thermal insulation, in particular at least one outer layer of insulating sheet, equipped with a surface are that have an emissivity less than 0.1. In one embodiment these layers of insulating sheet consist of one material the desired emission properties, in another embodiment lies on the surface a layer of material made of another material exists, as the majority of the insulating sheet layer otherwise. The layer can, for example, have been evaporated.

Figur 1

einen zylindrischen Wabenkörper mit einer gewickelten Wärmeisolierung in perspektivischer Darstellung,

Figur 2

einen Schnitt durch einen Wabenkörper mit zwei Mantelrohren,

Figur 3

einen Wabenkörper mit einer Wärmeisolierung aus einem Blechband,

Figur 4

einen Wabenkörper mit einer Wärmeisolierung aus zwei Blechbändern,

Figur 5

ein Stück einer Isolierblechlage mit Mikrostruktur und mit einer Anti-Emissionsschicht,

Figur 6

eine Isolierblechlage mit parallelen Mikrostrukturen, die sich nach beiden Seiten der Isolierblechlage erheben,

Figur 7

eine Isolierblechlage mit gekreuzten Mikrostrukturen,

Figur 8

eine Isolierblechlage mit Mikrostrukturen parallel zu einer stirnseitigen Kante,

Figur 9

einen Teilschnitt durch einen Wabenkörper mit einer Wärmeisolierung, die aus Isolierblechlagen mit und ohne Mikrostrukturen besteht, und

Figur 10

einen Teilschnitt durch einen Wabenkörper mit einer Wärmeisolierung, die zweiseitig mikrostrukturierte Isolierblechlagen aufweist.

Further advantages of honeycomb bodies according to the invention are explained on the basis of the drawing. However, the invention is not limited to the exemplary embodiments listed there. The individual figures of the drawing show:

Figure 1

a cylindrical honeycomb body with a wound thermal insulation in a perspective view,

Figure 2

a section through a honeycomb body with two jacket tubes,

Figure 3

a honeycomb body with thermal insulation from a sheet metal strip,

Figure 4

a honeycomb body with thermal insulation from two metal strips,

Figure 5

a piece of an insulating sheet layer with a microstructure and with an anti-emission layer,

Figure 6

an insulating sheet layer with parallel microstructures that rise on both sides of the insulating sheet layer,

Figure 7

an insulating sheet layer with crossed microstructures,

Figure 8

an insulating sheet layer with microstructures parallel to an end edge,

Figure 9

a partial section through a honeycomb body with thermal insulation, which consists of insulating sheet layers with and without microstructures, and

Figure 10

a partial section through a honeycomb body with thermal insulation, which has microstructured insulating sheet layers on two sides.

In Figure 1 is a preferred embodiment 1 of an inventive Honeycomb body shown. The core consists of a large number of honeycombs 2, which are formed by coiled, smooth and corrugated sheet layers. The Honeycombs form the end faces 10 connecting channels. The core is from a cylindrical jacket tube 6, which in turn from the thermal insulation 43 is included. The heat insulation 43 has in the embodiment Layers of insulating sheet metal, one 4 smooth and another 34 is microstructured on both sides 5. Figure 1 shows a snapshot a point in time just before the two insulating sheet layers 4 and 34 completely to be wrapped around the core.

Figure 2 shows a honeycomb body with a core as in Figure 1, of an inner jacket tube 6 is included. The outside of the inside Jacket tube 6 subsequent heat insulation 3 has in relation to Diameter of the core has a much greater thickness than that in the figure 1 shown embodiment. The heat insulation 3 is from a second, outer jacket tube 6 comprises.

A special structure of thermal insulation 23 can be seen in FIG. The insulating sheet layers 24 are part of a continuous spiral wound Sheet metal strip 11 with microstructures 5, which are on the inner side of the Raise sheet metal strip 11. The sheet metal strip 11 is at its beginning 8 connected to the casing tube 6. At its end 9 it is at another Section attached by itself.

Figure 4 shows another possible construction of thermal insulation The structure is similar to that in FIG. 1, but here the microstructures 5 run the sheet metal strip 11 in a direction approximately parallel to the channels, while in the example of FIG. 1 they run approximately transversely to it. The Thermal insulation 33 exists, in contrast to thermal insulation 23 in FIG 3, from two metal strips 11; 12, one of which is 12 smooth, i.e. no Has microstructures 5.

5, two details of an insulating sheet layer 14 can be explained. The insulating sheet layer 14 has approximately the same on its microstructure 5 Thick as usual. Such a microstructure is created, for example by stamping or bending the insulating sheet layer 14. Another possibility the creation of microstructures consists in the application of additional Material on an insulating sheet layer. The insulating sheet layer 14 is layered built up. The thinner anti-emission layer 15 forms a continuous one Surface on one side of the insulating sheet layer 14. It is from the base material 16 worn. An anti-emission layer 15 can e.g. are applied galvanically to the base material 16.

FIG. 6 shows an insulating sheet layer 34 in which the microstructures 5 have a Have a group of parallel ridges running in a line-like manner. The ridges rise alternately on both sides of the Isolierblechlage 34. The microstructures 5 meet perpendicularly on the front Edge 10 of the insulating sheet layer 34.

By combining such an insulating sheet layer 34 with insulating sheet layers the same type can be a particularly advantageous structure of thermal insulation Reach 3. The insulation sheet layers are in with each other crossed ridges stacked on top of each other. The crossed ridges touch each other only approximately point-like contact points at twice the distance of the parallel microstructures 5. Touching an insulating sheet layer 34 to a lower and an upper stack neighbor are at a distance from the parallel microstructures 5. For the distances between parallel microstructures, values between 1 mm and 20 mm favorable, values between 5 mm and 15 mm preferred become. Heat in a general direction perpendicular to the insulation sheet layers 34 is routed through considerable detours. Because of this detour and due to the point-like contact points becomes a achieved a particularly high thermal insulation effect.

The embodiment of an insulating sheet layer 44 shown in FIG Microstructures 5 is due to the direction of intersection Ridges mechanically particularly stable. You can, depending of the desired bending radius, possibly only bend in certain directions and wrap it around a honeycomb core. As the ridges follow raise exactly one side of the insulating sheet layer 44, the insulating sheet layer 44 on the other side advantageously with insulating sheet layers 14; 24; 34; 44 combined, which also have microstructures. The combination with Insulating sheet layers without microstructures would become one on one side undesirable large-area contact. In particular, the Combination with insulating sheet layers 14; 24; 34, their overall picture of microstructures themselves regarding the shape, the crossing angle and / or the Distance of the microstructures from the overall picture of the insulating sheet layer 44 differs. In this way, microstructures can be prevented an insulating sheet layer in the microstructures of another insulating sheet layer can intervene positively. Figure 8 shows an insulating sheet layer with microstructures 5, which are suitable for a favorable combination with that in FIG 7 insulating sheet layer shown is suitable.

In FIGS. 9 and 10, pieces of each are in a partial section Honeycomb core and thermal insulation 43; 53 shown. The Transition from core to thermal insulation 43; 53 takes place via a Insulating sheet layer 4 without microstructures (FIG. 9) or via an insulating sheet layer 34 with microstructures (Figure 10). The insulating sheet layers 4; 34 each form a stack, but with a different stacking sequence. In FIG. 10, all of the insulating sheet layers 34 are microstructured on two sides. In Figure 9 have the insulating sheet layers 34 with the microstructures at least an insulating sheet layer 4 without microstructures as the next following neighbor.

The cylindrical spatial shape shown in Figure 1, or that in others Circular cross sections shown in figures are by no means the only ones Possibilities for the shape of a honeycomb body according to the invention. Examples for other shapes there is a conical spatial shape or a polygonal one Cross-section. A thermal insulation 3; 23; 33; 43; 53 with microstructured Insulating sheet layers can also be relative to other than shown in the figures Arrange honeycomb 2. For example, it can only enclose the honeycombs 2 on one side, or there may also be honeycombs 2 outside of it.

Reference list

1

Honeycomb body

2nd

Honeycomb

3rd

Thermal insulation

4th

smooth insulating sheet layer

5

Microstructure

6

Casing pipe

7

Insulating sheet layer as protection against damage

8th

Start of sheet metal strip

9

Sheet metal strip end

10th

Face

11

Sheet metal strip with microstructure

12th

Sheet metal band without microstructure

14

Insulating sheet layer with anti-emission layer

15

Anti-emission layer

16

Base material

23

Thermal insulation from a sheet metal strip

24th

microstructured insulating sheet layer on one side

33

Thermal insulation from two metal strips

34

double-sided micro-structured insulating sheet layer

43

Thermal insulation with micro-structured and smooth sheet metal layers

44

Insulating sheet layer with crossed microstructures on one side

53

Thermal insulation from micro-structured sheet metal layers

Claims (12)

1. A honeycomb body comprising a plurality of honeycombs and a thermal insulation (3; 23; 33; 43; 53) comprising a plurality of stacked and/or wound insulating sheet layers (4; 7; 14; 24; 34; 44) characterised in that the insulating sheet layers (4; 7; 14; 24; 34; 44) are in mutually supporting relationship by virtue of microstructures (5) provided in the insulating sheet layers (14; 24; 34; 44) so that intermediate spaces exist between the insulating sheet layers (4; 7; 14; 24; 34; 44), wherein the microstructures (5) are of a height of from 15 µm to 250 µm.
2. A honeycomb body according to claim 1 characterised in that the thermal insulation (3; 23; 33; 43; 53) only partially surrounds the honeycombs (2).
3. A honeycomb body according to claim 1 or claim 2 characterised in that it is a converter for the catalytic conversion of exhaust gases, in particular exhaust gases from internal combustion engines, in particular Otto-cycle engines.
4. A honeycomb body according to claim 1, claim 2 or claim 3 characterised in that the insulating sheet layers (4; 7; 14; 24; 34; 44) are at least partially connected together by a procedure involving intimate joining of materials, preferably brazed.
5. A honeycomb body according to one of claims 1 to 4 characterised in that the honeycombs (2) have metal honeycomb walls which are formed by wound, smooth and corrugated sheet layers.
6. A honeycomb body according to claim 5 characterised in that the metal honeycomb walls are at least partially connected together by a procedure involving intimate joining of materials, preferably brazed.
7. A honeycomb body according to claim 5 or claim 6 characterised in that the material of the metal honeycomb walls and the material of the insulating sheet layers (4; 7; 14; 24; 34; 44) differ from each other, wherein in particular the former is resistant to corrosion at temperatures over 800°C and the latter is less resistant to corrosion.
8. A honeycomb body according to one of claims 5 to 7 characterised in that a part of the honeycomb walls is connected to at least one of the insulating sheet layers (4; 14; 24; 34; 44) by a procedure involving intimate joining of the materials, preferably brazing.
9. A honeycomb body according to one of claims 1 to 8 characterised in that it has a tubular casing (6), in the tubular interior of which are disposed the honeycombs (2).
10. A honeycomb body according to one of claims 1 to 7 characterised in that it has a tubular casing (6) and that the thermal insulation (3; 23; 33; 43; 53) lies outside the tubular casing (6).
11. A honeycomb body according to one of claims 1 to 10 characterised in that the outermost insulating sheet layer (7) is thicker than the insulating sheet layers (4; 14; 24; 34; 44) which are disposed within same.
12. A honeycomb body according to one of claims 1 to 9 characterised in that it has a tubular casing (6), in the tubular interior of which the thermal insulation (3; 23; 33; 43; 53) is disposed.

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