EP0818615A2 - Catalyst housing - Google Patents

Abstract

The housing comprises a tubular central section (1), a funnel (2,3) and a catalytic converter core (4). The larger diameter end (7,8) of the funnel is connected to the central section, and the wall thickness of this funnel end is maximum 90% of the material thickness of its smaller diameter end. The minimum wall thickness is 40% and preferably at least 55%. The larger diameter may be formed by expansion of the funnel material. The smaller diameter may be formed by reducing the funnel material in a die. The funnel may be manufactured from a tubular blank.

Description

The invention relates to a catalyst housing according to the preamble of claim 1.

Catalytic converter housing, as used to connect a catalytic converter in exhaust systems from Internal combustion engines, in particular motor vehicles, are used, are available in a variety of designs, with two systems prevailing on the market to have. According to the first system, one with a catalytically active material coated monolith (ceramic or metallic design) with an inflatable mat wrapped, which has the task of storing the monolith. On this inflatable mat again put a sheet metal jacket, which is wound with a fixed force and this keeps the monolith in place. This tense sheet metal jacket is to the End faces stapled, which ensures a tight fit of the monolith. Face Inlet and outlet funnels are installed that meet the requirements (Connection of the exhaust pipe) are aligned. It is attached using a Round weld seam on the wound converter. After closing the sheet metal jacket the finished winding converter is obtained by means of a weld seam. Despite the high The functional and process reliability of this winding converter were used in series production Vulnerabilities identified. On the one hand, the high weight turns out to be disadvantageous and on the other hand a fluidically often unfavorable connection of the funnels the monolith surfaces.

Another embodiment of a catalyst housing on the market which Shell converter, circumvents these disadvantages. In contrast to the winding converter Shell converter made from the monolith, an impregnated inflatable mat and two half shells (an upper and a lower shell). However, the shell converter is lacking Process reliability and also the geometry determined by the shell shape Difficulty adapting to the underbody of motor vehicles. With variable Underbody of motor vehicles is also a difference in the connection pipe converter to compensate by a complicated and therefore costly pipe adjustment.

When installing the shell converter, the inflatable mat becomes an organic liquid submerged to make it easier to assemble. This organic liquid evaporates then, so that the inflatable mat becomes very porous. In addition, the thermal stress on the converter the converter shells in contrast to that Monoliths very different, so that for a safe function of the Shell converter a production with very tight tolerances is necessary. At a The monolith gets non-compliance with the tolerances after the commissioning of the Motor vehicle freedom of movement that can lead to failure of the catalytic converter. Such catalyst housing arrangements are known for example from DE 42 23 648 C, DE 38 21 397 C, DE 38 11 224 C and DE 37 29 994 A.

Another difficulty in the manufacture of the catalyst housing is the connection of the funnel to the housing body. The funnel that has the task of Differences in diameter between the inlet or outlet tube and the catalyst body to compensate should on the one hand ensure a controlled exhaust gas flow and on the other hand Protect the inflatable mat from being washed out by the pulsating exhaust gas flow. Therefor the funnel collar is usually placed in a 90 ° angle to the funnel axis, as is the case for example from DE 34 30 398 A, Figure 5 is known.

Such funnels are usually made from sheet metal by deep drawing, however, there are two disadvantages. On the one hand you need sheet metal boards with a high thickness in order to make a still weldable small diameter for the Obtain connection of the exhaust pipe. The second disadvantage is the 90 ° funnel adjustment to the funnel collar, which is welded to the catalytic converter housing. It can happen that depending on the location of the monolith in its Tolerance field and possible decentralized fastening of the funnel collar to the An effective monolith surface of up to 15% is covered. A Improvement here shows the funnel connection according to FIG. 1 of DE 34 30 398 A, in which there is only a slight overlap of the effective monolith face. This However, connection requires high precision in the manufacture of the housing parts and the Funnel, since otherwise it is not possible to insert the funnel into the housing with a precise fit.

This is made even more problematic by the welding of three present in FIG. 1 Sheet layers at the entrance funnel.

Another funnel connection is known from DE 34 30 399 A, in which the Large diameter of the funnel is folded over the catalyst housing. However, this is a very complex process and does not eliminate the disadvantage of a possible Coverage of the effective catalyst face.

The object of the present invention is to provide a catalyst housing with a low weight and on the other hand to produce with a favorable exhaust gas flow.

This object is achieved with the features of the light weight Catalyst housing according to claim 1 and / or 7; in terms of cheap Exhaust gas flow with the features of claim 12. The is particularly preferred Combination of these features.

The subclaims show particularly preferred embodiments.

The invention therefore uses the basic concept of the introduction described first Catalytic converter housing, in which the housing jacket is not formed in one piece with the funnel is.

According to the invention, the inlet and / or outlet funnel of the catalyst housing a so-called tube funnel is used instead of a deep-drawn funnel. That is, the The blank geometry of the funnel is a tube. The pipe is placed in a follow-on tool required large diameter expanded and the required small diameter moved in. The tube is preferably pulled in by pressing (Pulling) the tube funnel into a die.

For a simple manufacturing process, the tube funnel is manufactured in two stages, whereby the widening of one end takes place on the retraction or vice versa. Because of this It is possible to process the blank (semi-finished product) with the thickness just required provided, which is necessary for the expansion.

According to the funnel has on its large diameter a material thickness that is at most 90% of the material thickness on its small diameter. Especially the material thickness at the large diameter is at most 80%. That is advantageous Material thickness on the large diameter, however, at least 40% and in particular at least 60% of the material thickness on the small diameter, otherwise the funnel will close again becomes difficult and on the other hand the weldability either on the large diameter or on the Small diameter becomes problematic. With this thickness distribution on the funnel it is possible, weight optimized on the one hand and easy to weld on the other To design both ends, so that on the one hand the separate catalyst jacket without problems on the large diameter of the funnel and the separate exhaust pipe on the Small diameter of the funnel can be welded.

In contrast, the hoppers of the prior art have an opposite Weight distribution, d. H. the large diameter has a thicker wall thickness than that Small diameter, which makes these funnels much heavier.

Through the combined production of the pipe funnel by expanding the large diameter and pulling the small diameter is achieved that on the one hand the funnel material its large diameter does not become too thin and secondly the small diameter of the Funnel receives a not excessively high material thickness. In addition, this Manufacturing method avoided a possible material expansion on the large diameter. The manufacturing method of pulling in and widening becomes a particularly cheap one Wall thickness distribution as well as mass distribution on the two diameters of the Funnel reached.

To also the disadvantages of connecting the funnel to the separate middle part of the To avoid the catalyst housing, the wide end of the funnel with its front side attached to a connection slope of the middle part and there in particular by soldering or welding connected. Likewise, the middle part with one of its end faces be connected to a connection slope of the large diameter of the funnel, wherein however, the first embodiment is preferred. The connection slope is off manufacturing reasons preferably directed inwards. The is manufactured Connection slope advantageous due to rolling.

The length of the connection slope is advantageously kept as short as possible, i. H. so, that within the allowable manufacturing tolerances for the middle section and the funnel seamless connection of the two parts is possible. The connection slope is advantageous at an angle of 10 ° to 70 ° and in particular from 20 ° to 50 ° to the longitudinal axis, since under this geometry, larger manufacturing tolerances with short connection bevels possible are.

The part that crosses the connection bevel can also be provided with a connection bevel be formed, which is then directed opposite (to the outside). This The connection slope advantageously has an angle to the longitudinal axis ≤ the angle of the internal bevel.

Due to the connection bevel, not only a diameter tolerance is advantageous on Funnel or the middle part balanced, but also almost no effective at the same time Monolith surface covered, with the funnel geometry (cf. DE 34 30 398 and 34 30 399) is simplified.

According to the invention, ceramic or metallic are preferably used as the catalyst core Monoliths are used, with one or more monoliths in the middle part of the Catalyst housing can be accommodated.

The tubular middle part in which the catalyst core is located is very particularly preferred located, wound, d. H. is - as described at the beginning - from a sheet metal strip manufactured, which the catalyst core (with a the catalyst core against the middle part supporting intermediate layer, especially mat) wrapped.

According to the invention, the funnel described above is preferably inlet and arranged on the outlet side of the middle part.

The invention is explained in more detail below with the aid of an exemplary embodiment and drawings described.

Figur 1

ein Katalysatorgehäuse gemäß dem Stand der Technik;

Figur 2

ein Katalysatorgehäuse mit Rohrtrichtern; und

Figur 3

einen Schnitt durch den Mittelteil des Katalysatorgehäuses.

Show it

Figure 1

a catalyst housing according to the prior art;

Figure 2

a catalyst housing with tube funnels; and

Figure 3

a section through the central part of the catalyst housing.

FIG. 1 shows the winding converter 20 which is common today and which is constructed from a middle part 21 and an inlet funnel 22 and an outlet funnel 23 Sheet metal jacket 21 encloses a catalytically coated monolith 24 below Intermediate layer of an inflatable mat 25.

In the manufacture of the winding converter 20, the catalytically coated monolith 24 wrapped with the inflatable mat 25, which has the task of storing the monolith 24. On the Inflatable mat 25 is then placed on the sheet metal jacket 21 and with a predetermined force wrapped (pulled) over the inflatable mat. This will tension the unit. The tense Sheet metal jacket 21 is then stapled on its end faces, whereby a tight fit of the Monolith 24 is guaranteed. In subsequent steps, sheet metal blanks are deep-drawn Funnels 22, 23 attached to the end faces of the sheet metal jacket 21 and welded 26. Zum Compensation of tolerances have the funnels 22, 23 funnel bundles 27, 28 which in one 90 ° to the longitudinal axis. The funnel bundles result from Deep drawing the funnels 20 to 23 from the corresponding sheet metal plates by clamping the edge of the board.

The funnel edge 27 or 28 accordingly has the greatest material thickness of the funnel 22 or 23, since there is almost no pulling of the material here. This thickness exceeds the thickness of the Small diameter 29 or 30, since the starting thickness of the sheet metal plate can be chosen in this way must that the small diameter after deep drawing a still weldable thickness for the Have joining and welding with the inlet or outlet pipe (not shown). From From the manufacturing point of view, there is the problem that the wall thickness during deep drawing the large diameter is equal to the blank wall thickness (the sheet metal plate). At the Small diameter 29 or 30, however, the wall thickness is far below due to the deformation the blank wall thickness. But since there is also a welded joint on no diameter a minimum wall thickness is required here. This certain minimal Wall thickness can only be influenced by changes in the blank dimensions, so that the raw part wall thickness and thus the part weight for production must be increased, although it is not necessary for the connection to the middle section.

Another disadvantage is the funnel setting 27 or 28, which means that it depends radial position of the monolith 24 in its tolerance field a concealment 31 of up to 15% the cross-sectional area F of the monolith 24 can come.

These disadvantages are overcome with the catalyst housing 10 according to the invention (FIG. 2) avoided. Come for the input funnel 2 as well as the output funnel 3 Pipe funnels are used, the raw part geometry of which is a pipe. This tube is in two Manufacturing operations expanded or contracted, resulting in large diameters 7 and 8 respectively with relatively low wall thicknesses, which can also be welded. Since the If the wall thickness is low due to the large diameter 7 or 8, the pipe funnels 2 and 3 are much lighter than the funnels 22 and 23, in which the low wall thickness on Small diameter 29 or 30 is.

Furthermore, the pipe funnels 2 and 3 avoid the connection problems to the sheet metal jacket 1 with a new connection geometry. With this connection, the sheet metal jacket 1 is on its ends 11 and 12 at an angle of approx. 30 ° to the horizontal (longitudinal axis) inclined so that there are connection bevels. On these connecting slopes 11 or 12 are diameter tolerances of the wound sheet metal jacket 1 compared to Large diameters 7 and 8 of the tube funnels 2 and 3 compensated. This allows the Large diameter 7 or 8 axially parallel to the connection bevels 11 or 12 be welded on. At the same time, the connecting slopes 11 and 12 cover the Inflatable mat 5, so that they are not washed out by the pulsating exhaust gas flow can. On the other hand, the channels 13 of the catalyst core are not covered 4, so that its effective cross section can be fully used.

In Figure 3 it can be seen that in the embodiments according to Figure 1 or Figure 2 in Cross section no difference. Both times there is a wound sheet metal jacket 1 or 21 before, which is welded at 14 overlapping to a pipe part. Inside the sheet metal jacket 1/21 the catalyst core (monolith) 4/24 is arranged, which is opposed by a mat 5/25 supports the sheet metal jacket 1/21. For the entire middle part there is preferably only that Difference of the connection bevels 11 and 12 when they are in the sheet metal jacket 1 are molded.

It can also be seen from the figures that according to the invention, just as in the case of Technology that funnels 2 and 3 can be performed asymmetrically. For this, the tubular blank preferably first drawn into a die at one end and then, to produce the large diameter, asymmetrical to the longitudinal axis of the Small diameter widened.

Claims (17)

Catalytic converter housing, in particular for exhaust systems from Internal combustion engines, in particular in motor vehicles, made of metallic Parts is composed, of which a part is a tube-like central part in particular (1) and at least one is a funnel (2; 3) with its large diameter (7; 8) is connected to the central part (1), which receives a catalyst core (4), and the with its small diameter (9; 9 ') with a part supplying or discharging a fluid, in particular a pipeline, is connectable or connected, thereby characterized in that the funnel (2; 3) at its large diameter (7; 8) at most Has 90% of the material thickness of its small diameter (9; 9 '). Catalyst housing according to claim 1, characterized in that the Large diameter a material thickness of at most 80% of the material thickness of the Small diameter. Catalyst housing according to claim 1 or 2, characterized in that the Large diameter at least 40%, in particular at least 55% of the material thickness of the small diameter. Catalyst housing according to one of the preceding claims, characterized characterized in that the large diameter by stretching, especially widening of the funnel material is made. Catalyst housing according to one of the preceding claims, characterized characterized in that the small diameter by drawing, especially in a Matrix, the funnel material is made. Catalyst housing according to one of the preceding claims, characterized characterized in that the funnel is made from a piece of pipe. Catalytic converter housing, in particular for exhaust systems from Internal combustion engines, in particular in motor vehicles, made of metallic Parts is composed, of which a part is a tube-like central part in particular (1) and at least one is a funnel (2; 3) with its large diameter (7; 8) is connected to the central part (1), which receives a catalyst core (4), and the with its small diameter (9; 9 ') with a part supplying or discharging a fluid, in particular a pipeline, is connectable or connected, thereby characterized in that the funnel (2; 3) from a piece of pipe by expanding the one end and retraction of the other end is formed. Catalytic converter housing according to claim 7, characterized in that the drawing in a die has been made. Catalyst housing according to claim 7 or 8, characterized in that the Funnel (2; 3) expanded in two successive manufacturing operations or moved in. Catalyst housing according to one of the preceding claims, characterized characterized in that the large diameter (7; 8) of the funnel (2; 3) with its End face connected on a connecting slope (11; 12) of the central part (1), in particular is soldered or welded. Catalyst housing according to one of claims 1 to 9, characterized in that the middle part (1) with one of its end faces on a connection slope of the Large diameter of the funnel connected, in particular soldered or welded is. Catalytic converter housing, in particular for exhaust systems from Internal combustion engines, in particular in motor vehicles, made of metallic Parts is composed, of which a part is a tube-like central part in particular (1) and at least one is a funnel (2; 3) with its large diameter (7; 8) is connected to the central part (1), which receives a catalyst core (4), and the with its small diameter (9; 9 ') with a part supplying or discharging a fluid, in particular a pipeline, is connectable or connected, thereby characterized in that the large diameter (7; 8) of the funnel (2; 3) with its End face connected on a connecting slope (11; 12) of the central part (1), in particular is soldered or welded, or that the central part (1) with one of its End faces on a connection slope of the large diameter of the funnel connected, in particular soldered or welded. Catalyst housing according to one of claims 10 to 12, characterized in that that the connection bevel at an angle between 10 ° to 70 °, in particular 20 ° is up to 50 ° to the longitudinal axis of the catalyst core, and / or that Connection slope is angled inwards. Catalyst housing according to one of the preceding claims, characterized characterized in that in the central part (1) one or more ceramic or Metallic catalyst cores (4) (monoliths) are arranged. Catalyst housing according to one of the preceding claims, characterized characterized in that the central part (1) is wound, in particular from a Metal strips. Catalyst housing according to claim 14 and 15, characterized in that the Middle part (1) around which the catalyst core (4) is wound. Catalyst housing according to one of the preceding claims, characterized characterized in that funnels (2; 3) are arranged at both ends of the central part (1).

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