阅读说明：本技术 催化转化器 (Catalytic converter ) 是由 M·福伊特 S·塞弗特 H-F·科特霍夫 F·库尔斯 A·尼德曼 伊藤小作 V·萨达法尔 于 2019-08-20 设计创作，主要内容包括：本发明涉及一种用于对内燃机或其它排气源的排气进行后处理的催化转化器,该催化转化器具有外壳(1)和布置在外壳(1)中的蜂窝体,该蜂窝体具有多个能沿着催化转化器的轴向方向流过的流动通道,其中,蜂窝体与外壳(1)沿着在催化转化器的周向方向上至少部分延伸的钎焊连接部持久地连接,其中,外壳(1)在其向内指向的面上对于每个钎焊连接部具有至少两个限制装置(2、3),所述限制装置限制钎焊连接部的轴向扩散。(The invention relates to a catalytic converter for aftertreatment of exhaust gases of an internal combustion engine or of another exhaust gas source, comprising a housing (1) and a honeycomb body arranged in the housing (1) and having a plurality of flow channels which can flow through the honeycomb body in the axial direction of the catalytic converter, wherein the honeycomb body is permanently connected to the housing (1) along a soldered connection which extends at least partially in the circumferential direction of the catalytic converter, wherein the housing (1) has at least two limiting devices (2, 3) on its inwardly directed face for each soldered connection, which limit the axial diffusion of the soldered connection.)

1. A catalytic converter for aftertreatment of exhaust gases of an internal combustion engine or of another exhaust gas source, having a housing (1) and a honeycomb body arranged in the housing (1) and having a plurality of flow channels which can flow through it in the axial direction of the catalytic converter, wherein the honeycomb body is permanently connected to the housing (1) along a soldered connection which extends at least partially in the circumferential direction of the catalytic converter, characterized in that the housing (1) has at least two limiting devices (2, 3) on its inwardly directed face for each soldered connection, which limit the axial diffusion of the soldered connection.

2. A catalytic converter according to claim 1, characterized in that the limiting means (2, 3) is formed by two grooves (2, 3) which are at least partly circumferential in the circumferential direction.

3. A catalytic converter according to any of the preceding claims, characterized in that the groove (2, 3) is completely circumferential.

4. A catalytic converter according to any of the preceding claims, characterized in that the grooves (2, 3) are oriented parallel to each other.

5. A catalytic converter according to any of the preceding claims, characterized in that both grooves (2, 3) have the same internal volume.

6. A catalytic converter according to any of the preceding claims, characterized in that the grooves have different internal volumes.

7. A catalytic converter according to any one of the preceding claims, characterized in that every second groove (2, 3) is arranged directly adjacent to a solder strip arranged between the housing (1) and the honeycomb body in the axial direction.

8. A catalytic converter according to any one of the preceding claims, characterized in that the maximum depth of the two grooves (2, 3) corresponds to half the material thickness of the housing (1) in the region of the grooves.

9. A catalytic converter according to any one of the preceding claims, characterized in that the total internal volume of the two grooves (2, 3) is greater than the volume of the excess solder.

Technical Field

The invention relates to a catalytic converter for the aftertreatment of exhaust gases of an internal combustion engine or of another exhaust gas source, having a housing and a honeycomb body arranged therein, which has a plurality of flow channels that can flow through the catalytic converter in the axial direction, wherein the honeycomb body is permanently connected to the housing along a soldered connection that extends at least partially in the circumferential direction of the catalytic converter.

Background

The invention relates to a honeycomb body for an exhaust gas treatment unit, comprising at least one honeycomb structure and at least one housing, which at least partially surrounds the at least one honeycomb structure. The invention relates in particular to the formation of a brazed/hard solder connection between a honeycomb structure and a housing. Such honeycomb bodies are frequently used for purifying exhaust gases in motor vehicles.

Such honeycombs generally have a metallic or ceramic honeycomb structure. In particular, metal honeycomb structures which are fixed to or in the housing by means of a brazed connection are considered here, although the following aspects are also widely applicable to ceramic honeycomb structures. The formation of a targeted brazed connection is particularly important to ensure a permanent connection of the honeycomb structure and the housing. This results from the fact that the two components exhibit different thermal and dynamic behavior in the exhaust system of a mobile or stationary internal combustion engine. For a certain relative movement of the honeycomb structure and the housing with respect to one another, it is desirable that the two are only partially brazed to one another, i.e. not over the entire circumference or contact surface.

In principle, a plurality of possibilities for how and at which locations the hard solder is applied and the brazed joint is produced have been described. However, it has not yet been fully taken into account that conditions may already exist which lead to the final extension of the brazed joint beyond the desired region, even during the brazing process itself, or even during the assembly of the honeycomb body or during subsequent storage or transport. This diffusion of the braze joint beyond the expected range leads to a change in the thermal expansion behavior of the honeycomb body, which in some cases may lead to failure of the honeycomb body.

The disadvantage of the devices of the prior art is, in particular, that the diffusion of the brazed connection in the axial direction of the catalytic converter cannot be sufficiently limited in order to precisely define the extension of the brazed connection in the axial direction.

Disclosure of Invention

It is therefore an object of the present invention to provide a catalytic converter having a housing and a honeycomb body arranged therein, wherein the honeycomb body is connected to the housing by means of a brazing process, wherein the diffusion of the brazed connection in the axial direction of the catalytic converter can be precisely defined or limited.

The object with respect to the catalytic converter is achieved by a catalytic converter having the features of claim 1.

One embodiment of the invention relates to a catalytic converter for aftertreatment of exhaust gases of an internal combustion engine or of another exhaust gas source, having a housing and a honeycomb body arranged therein, which has a plurality of flow channels which can flow through it in the axial direction of the catalytic converter, wherein the honeycomb body is permanently connected to the housing along a braze joint which extends at least partially in the circumferential direction of the catalytic converter, wherein the housing has at least two limiting devices on its inwardly directed face for each braze joint, which limit the axial diffusion of the braze joint.

The housing is preferably designed as a tube, into the inner cross section of which the honeycomb body can be inserted. The tube has a defined wall thickness. Solder, for example in the form of embedded solder strips or solder coatings, is applied between the tubes and the honeycomb body for producing the catalytic converter. The solder melts by the application of heat and, on cooling, produces a permanent, firm connection between the tube or housing and the honeycomb body.

The heated and liquid solder diffuses both in the circumferential direction of the catalytic converter and in the axial direction of the catalytic converter by capillary forces acting between the honeycomb body and the housing.

Although a distribution in the circumferential direction is desired and a distribution along the entire circumference depending on the design of the connection is desired, it is desired to diffuse only within defined limits in the axial direction. In particular, it should be avoided that liquid solder migrates into the structure forming the flow channel and thus blocks the flow channel. By precisely defining the connection length between the housing and the base body in the axial direction, it is also ensured that the properties of the connection under thermal stress are precisely known and that it is thus possible to ensure that the connection is permanently secured during operation of the catalytic converter. Therefore, it is necessary to accurately know the spatial extension of the connection portion. A connection that is too long in the axial direction can lead to the formation of cracks, since the housing and the honeycomb body generally have different material properties and deform differently under thermal stress. An infinitely long connection may be too rigid to withstand the corresponding stresses.

The catalytic converter may have a plurality of connection sites. Typically, one connection between the honeycomb body and the housing is disposed on the inflow side and one connection is disposed on the outflow side of the catalytic converter. It is also conceivable to provide a central solder strip.

According to the invention, a limiting device is provided, which limits in particular the axial extension of the connection. In contrast to the solutions known from the prior art, each connection is provided with at least two limiting means.

The catalytic converter claimed herein and described further below is a metal-based catalytic converter. The honeycomb body of the catalytic converter consists of a metal honeycomb body, which is inserted into a metal housing.

It is particularly advantageous if the limiting means are formed by two grooves which at least partially surround in the circumferential direction. This is advantageous because the capillary action between the honeycomb body and the housing is weakened or completely interrupted by the grooves and a collecting volume for the liquid solder is also formed. The function of the capillary stop and collection volume cannot be defined exactly between the two grooves, since the second groove can also produce the effect of the capillary stop and collection volume, since the first groove facing the solder can overflow in the case of a sufficiently large amount of solder.

However, it has been shown that the second recess has a positive effect on limiting the axial diffusion of the connection. And the axial spread of the connection can be limited considerably more precisely than in an embodiment with a single groove.

It is also advantageous if the groove is formed completely circumferentially in the circumferential direction. A circumferential groove is advantageous in order to produce a completely circumferential connection and at the same time to ensure axial restraint of the connection along the entire circumferential length.

A preferred embodiment is characterized in that the grooves are oriented parallel to each other. The grooves oriented parallel to one another are advantageous, as a result of which the solder can be received uniformly and, in particular, a defined limit to the diffusion of the connection in the axial direction can be achieved.

It is also preferred that both recesses have the same internal volume. This is particularly advantageous for achieving a simpler manufacture. Furthermore, the same grooves also produce the same notching effect, so that the effects on the structural integrity can be better detected and planned.

It is also advantageous if the recesses have different internal volumes. Depending on the design of the individual recesses, it can also be advantageous if the internal volumes and thus the receiving volumes differ. Thus, for example, a recess facing the solder may serve as a first receiving recess having a larger internal volume than a second recess facing away from the solder. Thus, the second recess effectively acts as an overflow volume for the first recess.

In addition, it is advantageous if the two recesses are each arranged axially directly adjacent to a solder strip arranged between the housing and the honeycomb body. This is advantageous in order to limit as well as possible the diffusion of the solder in the liquid state. If the recess is arranged particularly close to the solder, the connection is actually produced only at the location that has already been loaded with solder before the soldering process. Here, the connection portion can be particularly accurately defined.

It is also expedient for the two recesses to have a maximum depth which corresponds to half the material thickness of the housing in the region of the recesses. In order for the recess not to jeopardize the structural integrity of the housing, the maximum possible depth of the recess is limited. In order to ensure a permanently firm structure of the housing, the recess should not be deeper than half the material thickness of the housing.

It is also expedient if the total internal volume of the two recesses is greater than the volume of the excess solder. This is advantageous to ensure that both grooves do not overflow and that the solder does not spread beyond the second groove in the axial direction.

Advantageous developments of the invention are described in the dependent claims and in the following description of the figures.

Drawings

Hereinafter, the present invention will be described in detail by way of embodiments with reference to the accompanying drawings. Shown in the attached drawings:

fig. 1 shows a cross-sectional view of a housing with a recess according to the invention.

Detailed Description

Fig. 1 shows a section through a housing 1 of a catalytic converter. A honeycomb body, not shown, is arranged in the interior of the housing 1.

The housing 1 has a first recess 2 and a second recess 3. The first recess 2 here faces the solder, not shown. The grooves 2, 3 have a width 4 and a spacing 5 from each other. In the embodiment shown, the width 4 coincides with the spacing 5 from each other. Alternative dimensions may be provided in other embodiments.

The grooves 2, 3 have an extension 6 in the radial direction of the housing 1. In the embodiment shown, the depth of the radial extension 6, i.e. the grooves 2, 3, is approximately half the material thickness of the housing 1.

The grooves 2, 3 in fig. 1 have a trapezoidal cross section and a narrower width 7 at their bottom. Alternatively, the groove can also be semicircular or the like. In principle, it is also possible to design the cross sections of the two grooves 2, 3 to be different from each other.

The grooves 2, 3 of fig. 1 have the same dimensions and therefore also the same internal volume. Depending on the design of the catalytic converter or housing and the amount of solder used, different designs of the two recesses can also be provided.

The embodiment of fig. 1 is in particular of an unlimited character and serves to illustrate the inventive concept.