DE4316870C2 - Method of manufacturing an exhaust gas purification device - Google Patents

Description

The invention relates to a method for manufacturing provide a device for cleaning Ver internal combustion engine exhaust, being a central component, the longitudinally composed of two partial shells and in which an exhaust gas treatment body is held, and an expanding inflow component and itself tapered downstream component through welded connections on longitudinal welding shelves of the central component and each through a circumferential weld connection between the Middle component and the inflow component or the Ab flow component to be connected.

In a known method of this type (DE 24 58 994 A1) is only one in the central component Exhaust treatment body available; the single-walled zu flow component and the single-wall flow component are with the interposition of compliant rings axially between itself and the exhaust gas treatment body welded to the middle component.

The invention has for its object a ratio make available manufacturing process. In particular, while preserving the benefits that come with the combination of middle component, inflow component and outflow component go hand in hand, a manufacturing cheap way to ensure the inclusion of the Thermal expansion and to deal with the longitudinal stol tolerances of the components involved.  

To achieve this object, the method according to the invention is characterized in that at least two longitudinally spaced exhaust gas treatment bodies are inserted into an intermediate ring or an intermediate ring half in the first partial shell of the central component while maintaining axial gaps;
that the double-walled inflow component and the double-walled outflow component are each introduced with their one end region into an end region of the first partial shell of the central component with such a precise positioning that an axial gap between the inner wall of the inflow construction part and of the outflow component and the adjacent one of the two exhaust gas treatment bodies;
and that after the second partial shell of the central component has been placed, the circumferential weld connections and the weld board weld connections are carried out.

The manufacture of emission control devices, at those widening between the inner wall of a Inflow area of the housing and a first exhaust gas act body, between the first exhaust treatment body and an intermediate ring, between the intermediate ring and a second exhaust treatment body, and between the second exhaust treatment body and the Inner wall of a tapered outflow area of the There is an axial gap in each case known from DE 39 08 887 A1 and DE 40 42 266 A1. Here at are the inflow range of the housing and the outflow area of the housing is not a separate construction share the ver with a central component of the housing be welded.  

With "cleaning of internal combustion engine exhaust gases" is on the one hand the chemical conversion of disadvantageous gaseous exhaust gas components, such as carbon monoxide, Nitrogen oxides, unburned hydrocarbons, in harmless compounds, such as carbon dioxide, stick substance and water, meant. This happens in the Usually harmful by oxidation Exhaust gas components and reducible reduction harmful exhaust gas components in the presence a catalyst. In this case, the exhaust gas treatment body usually one with a lot number of channels running lengthways Body in which the channel walls with a kataly table-acting substance, e.g. B. on the basis of Platinum, are coated.  

"Cleaning internal combustion engine exhaust gases" means on the other hand, the greatest possible harm Treatment in the exhaust gas of diesel engines particles, which are often also simplistic "Soot particles" are called. It can be filtering these particles out of the exhaust gas trade electricity, often simplifying a "soot filter" speaks. But it can also to oxidize such particles or even combinative removal of particles and harmful gaseous exhaust gas components, the latter in turn with the help of a catalyst. As a result, in the case of diesel engine exhaust the exhaust gas treatment body is often a filter body. Porous ceramic bodies are used as filter bodies common. But so-called wrapping film is also known ter, which is made of threads from heat-resistant gem material, e.g. B. glass fiber or ceramic fiber, are wrapped.

For exhaust gas treatment bodies for catalytic Exhaust gas cleaning are ceramic bodies or metal body, each with a variety of Longitudinal channels, known.

If the inflow component and that Outflow component each with one end region telescopically in an end area of the middle building partly used are created at the front ends of the Sheet metal of the central component is welded optimal weld throat. He also enforces Telescopic seat when assembling the components themselves active tolerance compensation. If e.g. B. a kera mixer exhaust treatment body with from the target Shape of slightly different cross-sectional shape in the  Housing of the middle component is attached this housing the tendency, this also from the target assume a different cross-sectional shape. By the Telescopic seat with the subsequent inflow component or the downstream outflow component Housing pressed towards the target shape. The same applies in reverse for shape deviations of the inflow component and the outflow component. It is also pointed out that the "vice returned telescopic seat ", ie the end area of the Housing of the middle component within the endbe realm of the inflow component or the outflow construction partly, is possible.

Several smaller exhaust gas action bodies in a row are cheaper than a single, correspondingly larger exhaust gas action body. In addition, the partial cleaned exhaust gases before entering the second or third etc. exhaust treatment body again mix so that overall a more even and more complete exhaust gas cleaning is achieved.

To avoid that from the space between two exhaust gas treatment bodies hot exhaust gases to get to the housing or unhindered Support mat of the exhaust gas treatment body with the Danger of damaging them, is the intermediate ring surrounding the space intended. The intermediate ring can be made of sheet metal or Ceramics exist.  

In the case of an intermediate ring made of sheet metal, it is before pulls that the intermediate ring with two projections in complementary recesses in the welded shelves is sufficient and is welded to the housing there. The intermediate ring can be analogous to the partial shells of the Housing be divided into two and by this Welding into a complete ring.

It is further preferred in that area of the Housing, where the intermediate ring - be it from sheet metal or made of ceramic material - is arranged in Provide circumferential bead that at least as wide as the intermediate ring. This results in an improved positional fixation tion of the intermediate ring in the axial direction.

Preferably are at the inflow component and / or the outflow component the ends facing away from the central component of both Outside wall as well as the inside wall together with welded to a pipeline. This weld thus creates a connection between the Inner wall and the outer wall as well as an attachment of the inflow component or the outflow component with the pipeline. The emission control device is usually built into an exhaust system. The inflow component is therefore in usually around the pipeline through which the pre direction the exhaust gas to be cleaned flows in; to the Downstream component is the pipeline, through which the cleaned exhaust gas from the exhaust gas cleaning flow away.  

With the inflow component and / or the outflow construction part can be the end of the middle component facing Inner wall, directly or with interposition of an end ring, via a sliding seat on the Fit the outer wall. With the inflow component and with the Outflow component is the inner wall in the Operation much hotter than the outer wall. Info ge of the sliding seat can try the inner wall expand more effortlessly relative to the outer wall, so the risk of warping or tension tears or the like is minimized.

The housing of the central component is preferably made from a sheet of less wall thickness than the outer walls of the inflow component and Outflow component. In this context you have to be aware that the housing of the middle Component is larger than the inflow Component and the downstream component (if you consider the End areas facing away from the central component) has so that even with a sheet metal less Wall thickness a sufficiently high section modulus against bending is achieved.

Preferably, the outer walls of the inflow Component and the outflow component from corrosion  more permanent sheet metal than the housing of the middle construction partly because of the first two components higher operating temperatures and associated with it there is a greater risk of corrosion.

By the in the two previous paragraphs described measures can thus material and money savings on the housing of the Mittel-Bau partly realize.

The exhaust treatment bodies are usually with bracket mat laid around the middle component.  

The exact positioning of the components according to the invention before Welding can take place, for example, through appropriate stops a production device can be ensured. The length tolerances of all parts involved do not add up to an unfavorably large one Overall tolerance, but remain the individual Assigned to parts.  

Alternatively, it is possible to do the necessary Axial gaps between the components involved by interposed spacing tiles or Spacer rings made of combustible material put. The positioning of the individual parts at Assembly then takes place in that the individual parts be axially pushed together.

According to the invention Processes can be used for emission control devices different engine sizes and motor vehicles according to the modular principle in the most rational way manufacture. Middle components can differ inflow components and outflow components can be combined, especially what the angle direction of the infeed or outfeed Pipeline relative to the longitudinal axis of the central building partly or what the eccentricity of the feeding Pipeline or the outgoing pipeline in Relation to the central longitudinal axis of the central component  concerned. A distinction can be made between middle components length and manufactured with the inflow component len and the outflow components are combined, being in the longer middle components either longer exhaust treatment body or a larger one Number of exhaust gas treatment bodies are held can.  

The invention is illustrated below with the help of drawings Exhaust gas cleaning devices and parts of exhaust gas cleaning devices, those according to the inventive method can be produced, explained in more detail. It shows

Figure 1 is a partially broken Seitenan view of an exhaust gas purification device according to arrow I in Fig. 4.

FIG. 2 shows a partial section of an exhaust gas cleaning device modified compared to FIG. 1;

Fig. 3 is a partial section of a modified as compared to FIG 1 exhaust gas purification device.

Fig. 4 shows the device of Figure 1 in cross section along IV-IV.

Figure 5 shows a detail of a modified exhaust gas purification device in partial section.

Fig. 6 shows a detail of a modified exhaust gas purifying device in longitudinal section;

Fig. 7 shows a part of a modified exhaust gas cleaning device in longitudinal section;

Fig. 8 shows a part of a modified exhaust gas purification device in longitudinal section.

The exhaust gas cleaning device shown in FIG. 1 consists of a central component 2 , an inflow component 4 and an outflow component 6 . The cross-sectional shape of the central component 2 can be seen in Fig. 4. In Fig. 4 is also indicated in broken lines that two similar exhaust gas treatment devices can be arranged side by side under the floor of a motor vehicle.

In Fig. 4 is most easily recognizable that the housing 8 of the central component 2 from a - in Fig. 4 lower - first partial shell 10 and - in Fig. 4 upper - second partial shell 12 is put together. The two partial shells 10 and 12 are welded to one another on welding shelves 14 which run in the longitudinal direction of the central component 12 , as indicated by weld seams 16 . The welding rims 14 lie in a plane 18 which is inclined with respect to the horizontal.

In the middle part of the housing 2 , two exhaust gas treatment bodies 20 are held one behind the other in the axial direction with an axial distance between them. The exhaust gas treatment bodies 20 consist monolithically of rigid ceramic material, are traversed by a plurality of channels in the longitudinal direction and have a catalytically active coating on the channel walls. The exhaust gas treatment body 20 are held in the housing 8 in that they are each surrounded by a mounting mat 22 to be held during assembly of the housing 8 or the entire device by pressing together the mounting mats 22 preload voltage.

In the space 24 between the two exhaust treatment bodies 20 , an intermediate ring 26 made of sheet metal is arranged, the circumferential length and circumferential shape of which corresponds essentially to the outer circumference of the two exhaust treatment bodies. In the longitudinal section drawn above in FIG. 1, one can see the profiled shape of the intermediate ring 26 . The intermediate ring 26 is composed of two partial rings, each of which is bent outwards at its ends and, deviating from the other profiling, is flat. The four projections 28 formed in this way extend in pairs into complementarily shaped depressions 30 in the welding rims 14 , as can also be seen in FIG. 4. There, the projections 28 are se with the Gehäu 8 welded, thereby forming the complete intermediate ring 26 and is fixed relative to the housing. 8 On the outer circumference of the intermediate ring 26 there is an insulation strip 32 between the latter and the housing 8 , which also consists of two halves. Between the insulation strip 32 and the intermediate ring 26 there is a thin protective layer 34 , which extends in both axial directions beyond the clearance space 24 and ends between an exhaust gas treatment body 20 and its retaining mat 22 .

In that region where the intermediate ring is arranged in the housing 8, 26, the housing 8 is an embossed outward bead 36 which - is slightly wider than the intermediate ring 26 - as measured in the axial direction. In the area of the two welding rims 14 , the bead 36 is continuously guided outwards, as a result of which the sheet metal of the housing 8 is bent out of the welding board plane and the receiving recesses 30 are formed.

The inflow component 4 and the outflow component 6 , apart from differences in the dimensional geometry, are technically identical, the inflow component 4 expanding from left to right in FIG. 1 in the direction of the central component 2 and the outflow component 6 tapers in the direction from left to right in FIG. 1, ie away from the central component 2 . The inflow component 4 consists of a circumferential outer wall 38 , a circumferential inner wall 40 and an insulating mat 42 in between. The outer wall 38 and the inner wall 40 end on the left in a common plane. The inner wall 40 is bent on the right shortly before the end face of the adjoining exhaust gas treatment body 20 outward-backward and is in contact with the outer wall 38 with this bent end. In this way, a sliding seat is formed which enables the inner wall 40 to lengthen more than the outer wall 38 at the high operating temperatures of the device. The axial gap 44 between the described bend and the end face of the exhaust gas treatment body 20 allows this increase in length.

The outflow component 6 is constructed analogously, so that a repeated description is not necessary.

The inflow component 4 protrudes telescopically with its right end region in FIG. 1 into the left end region of the housing 8 . The same applies to the left end region of the outflow component 6 in FIG. 1. Using the throat between the relevant end face of the sheet metal of the housing 8 and the outer wall 38 of the inflow component 4 , a circumferential weld seam 46 is carried out.

The mounting mats 22 can be formed, for example, by a so-called swelling mat, which consists of ceramic fiber material and contains an addition of mica, so that it increases in volume under the action of heat. The insulation mat 32 and the insulation mats 42 can, for example, best consist of ceramic fiber material or glass fiber material. The protective layer 34 can consist, for example, of particularly heat-resistant ceramic fiber fabric or glass fiber fabric.

The sheet metal of the housing has a thickness of approximately 1 mm, while the outer wall 38 of the inflow component 4 and the outflow component 6 has a thickness of approximately 1.5 to 2 mm.

By Figs. 2 and 3 is intended to be illustrated that the means component 2 with minimal modification lower or higher for internal combustion engines performance can be adjusted by se the Gehäu 8 axially shorter than axially longer than in Fig in Fig. 1 or. 1 trains. Accordingly, there are axially shorter or axially longer exhaust gas treatment bodies in the housing. It is pointed out that the two exhaust gas treatment bodies 20 do not necessarily have to be of the same length and consequently the housing 8 does not necessarily have to be mirror-symmetrical to its central plane 48 . For example, starting from FIG. 1, the housing 8 could only be extended to the right of the intermediate ring 26 , so that to the left of the intermediate ring 26 a medium-length exhaust gas treatment body 20 and to the right of the intermediate ring 26 a long exhaust gas treatment body 20 according to FIG. 3 is present .

On the right in FIG. 1 it is indicated how the outflow component 6 is fastened by welding 50 to a pipeline 52 which continues. The end region of the pipeline 52 extends telescopically into the outflow component 6 . By welding 50 , the outer wall 38 and the inner wall 40 are connected to each other as well as to the pipeline 52 . The same applies to the left end of the inflow component 4 , where the feed pipe is not shown.

Fig. 5 illustrates a modified constructive tion of a sliding fit between the inner wall 40 and outer wall 38 of the Zuström-member 4. In the exhaust gas treatment body 20 adjacent Endbe rich, the outer wall 38 is bent backwards through 180 °, the inner wall 40 extends with its end into a gap of the bend. Between the end of the inner wall 40 and the bottom of the bending gap there is a free space 54 , into which the longitudinal growth of the inner wall 40 can take place when the temperature rises.

FIG. 6 illustrates a further, modified embodiment of the sliding seat between the inner wall 40 and the outer wall 38 of the inflow component 4 in the vicinity of the end face of the adjoining exhaust gas treatment body 20 . The end area of the inner wall 40 is similar to FIG. 1 bent outward-backward, but a little over 180 °. In this bend an end ring 56 is made of knitted metal, which is in contact with its outer circumference with the inner circumference of the outer wall 38 . The inner wall 40 itself is not in contact with the outer wall 38 in this area.

FIG. 7 shows a variant that is very similar to the embodiment according to FIG. 1 with regard to the sliding fit between the inner wall 40 and the outer wall 38 . The embodiment according to Fig. 7 has the special feature that the Zuström component 4 an angular orientation axis at about 45 ° relative to the longitudinal 58 of the center member 2 has. The inner wall 40 extends fairly close to the end face of the exhaust gas treatment body 20 , although an axial gap 44 remains. The inner wall 40 can expand freely in the longitudinal direction of the inflow component 4 as a result of the sliding fit.

The welding rims 14 can also be seen in FIG. 7.

The embodiment according to FIG. 8 has in common with the embodiment according to FIG. 7 the oblique Winkelaus direction of the inflow component 4 . However, the inflow component 4 kinks in the area of the telescopic engagement with the housing 8 of the central component 2 in the axial direction of the central component 2 . Similar to the embodiment according to FIG. 6, an end ring 56 made of knitted metal is provided, so that the sliding seat is formed between the outer circumference of this end ring 56 and the outer wall 38 .

It is also noteworthy that in Fig. 8 the possibility is drawn to design the inflow component analogous to the housing 8 in partial shell construction. There are welding flange 14 a is drawing net. It applies in general that the inflow component 4 and the outflow component 6 can be designed either with a one-piece circumferential outer wall 38 or in part shell construction according to FIG. 8.

In addition, it should be noted that the details described with reference to FIGS . 5 to 8 about possible educations of the inflow component 4 can also be carried out analogously for the outflow component 6 .

In addition, it is pointed out that the inflow component 4 and the outflow component 6 can optionally also be designed without an insulating mat 42 , only with an air gap between the outer wall 38 and the inner wall 40 .

Finally, it should be noted that Winkelaus directions of the inflow component 4 or the outflow component 6 relative to the longitudinal axis of the central construction part 2 can be made in any plane, in particular in a horizontal plane, but also obliquely up or down.

Claims (6)

1. A method for producing a device for cleaning internal combustion engine exhaust gases, wherein a central component ( 2 ), which is composed of two partial shells ( 10, 12 ) and in which an exhaust gas treatment body ( 20 ) is held, and an expanding part Inflow component ( 4 ) and a tapering outflow component ( 6 ) through welded joints ( 16 ) on longitudinal welded shelves ( 14 ) of the central component ( 2 ) and in each case by a circumferential welded connection between the central component ( 2 ) and the inflow component ( 4 ) or the outflow component ( 6 ) are connected to one another, characterized in that
that at least two longitudinally spaced exhaust gas treatment bodies ( 20 ) are inserted into the first partial shell ( 10 ) of the central component ( 2 ) while maintaining axial gaps to form an intermediate ring ( 26 ) or an intermediate ring half;
that the double-walled inflow component ( 4 ) and the double-walled outflow component ( 6 ) are each introduced with their one end region into an end region of the first partial shell ( 10 ) of the central component ( 2 ) with such precise positioning that each an axial gap ( 44 ) is maintained between the inner wall ( 40 ) of the inflow component ( 4 ) or the outflow component ( 6 ) and the adjacent one of the two exhaust gas treatment bodies ( 20 );
and that after the second partial shell ( 12 ) of the central component ( 2 ) has been placed, the circumferential welded connections ( 46 ) and the welded-board welded connections ( 16 ) are carried out. 2. The method according to claim 1, characterized, that the axial gaps from interposed spacers combustible material can be ensured.   3. The method according to claim 1 or 2, characterized in that the intermediate ring ( 26 ) via an interposed insulation mat ( 32 ), which differs in material from mounting mats ( 22 ) of the exhaust gas treatment body ( 20 ), in the central component ( 2 ) becomes. 4. The method according to any one of claims 1 to 3, characterized in that the intermediate ring ( 26 ) is positioned with the aid of a peripheral bead ( 36 ) of the central component ( 2 ). 5. The method according to any one of claims 1 to 4, characterized in that the intermediate ring ( 26 ) is composed of two intermediate ring halves, each of which is attached to a partial shell ( 10 , 12 ) of the central component. 6. The method according to any one of claims 1 to 5, characterized in that an intermediate ring ( 26 ) made of sheet metal is used.