Honeycomb body and method for producing the honeycomb body

Abstract

A honeycomb body for exhaust gas aftertreatment includes a plurality of interconnected metal foils stacked on one another. The honeycomb body has a central first flow channel running in the axial direction of the honeycomb body, as an inflow section, and has a plurality of second flow channels between in each case two mutually adjacent metal foils. The first flow channel is in fluid communication with the second flow channels. The second flow channels formed between two mutually adjacent metal foils run in a straight line and parallel to one another along a radial direction of the honeycomb body.

Claims

1. A honeycomb body for exhaust gas aftertreatment, comprising: a plurality of interconnected metal foils having a respective diamond-shaped cutout, each of the interconnected metal foils being stacked on one another; wherein the honeycomb body has a central first flow channel running in the axial direction of the honeycomb body, as an inflow section, and has a plurality of second flow channels between in each case two mutually adjacent metal foils; wherein the first flow channel is in fluid communication with the second flow channels; and wherein the second flow channels formed between two mutually adjacent metal foils run in a straight line and parallel to one another along a radial direction of the honeycomb body.

2. The honeycomb body as claimed in claim 1, wherein the second flow channels between mutually adjacent metal foils are formed by corrugations in the metal foils; and wherein metal foils which are in each case directly mutually adjacent are arranged rotated with respect to one another by an angle of at least 5 degrees about the central axis of the honeycomb body.

3. The honeycomb body as claimed in claim 2, wherein the first flow channel is formed by cutouts in the metal foils stacked on one another.

4. The honeycomb body as claimed in claim 3, wherein the respective cutout in the respective metal foils has a substantially longer first extent (8) in a direction transverse to the direction of extent of the second flow channels formed by the corrugation of the metal foil than the second extent of the cutout in a direction parallel to the direction of extent of the second flow channels formed by the corrugation of the metal foil.

5. The honeycomb body as claimed in claim 3, wherein the cutout along its first longer extent intersects at least 70%, or at least 80%, or at least 90% of the second flow channels formed in the respective metal foil.

6. The honeycomb body as claimed in claim 1, wherein the metal foils forming the honeycomb body are corrugated, wherein metal foils arranged directly mutually adjacent are arranged rotated with respect to one another by in each case 90 degrees around the central axis.

7. The honeycomb body as claimed in claim 1, wherein the second flow channels are aligned in the same direction across the honeycomb body and a smooth metal foil is arranged between each two metal foils having a corrugation.

8. The honeycomb body as claimed in claim 2, wherein the corrugated metal foils have a corrugation with wave crests and wave troughs which run parallel to one another and extend over the entire width of the metal foils.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in detail in the following text on the basis of exemplary embodiments with reference to the drawings. In the drawings:

(2) FIGS. 1A and 1B show a top view of two corrugated metal foils, wherein the left metal foil has a circular central cutout and the right metal foil has a diamond-shaped cutout;

(3) FIG. 2 shows a perspective view of a corrugated metal foil;

(4) FIG. 3 shows a perspective view of a honeycomb body composed of a plurality of metal foils stacked on one another;

(5) FIG. 4 show a perspective view of a honeycomb body composed of a plurality of metal foils stacked on one another, wherein non-corrugated smooth metal foils are also arranged between the corrugated metal foils; and

(6) FIG. 5 shows a view which clarifies the method sequence, wherein the processing path from an oval base foil to the corrugated round metal foil and finally to the stacked honeycomb body is shown.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(7) FIG. 1A in the left region shows a structured metal foil 1 with an embossed corrugation 2. The corrugation 2 produces wave crests and wave troughs which run parallel to one another and extend over the entire width of the metal foil 1.

(8) The metal foil 1 has a central cutout 3. The metal foil 1 and the cutout 3 have a circular circumference, which has resulted by the embossing of the corrugation 2 from the originally oval metal foil.

(9) The box 4 indicates the region of the metal foil 1 through which a flow can pass from the cutout 3 forming the first flow channel, since the second flow channels produced by the corrugation 2 open into the cutout 3 in this region or are intersected by said cutout. The arrows 5 indicate the possible flow through the second flow channels. It can be seen here that only a straight flow through the second flow channels opening into the cutout 3 is possible.

(10) In FIG. 1B, a metal foil 6 with a circular circumference is shown. In contrast to FIG. 1A, the metal foil 6 has a diamond-shaped cutout 7 which has a significantly larger spatial extent 8 in a direction transverse to the direction of extent 9 of the second flow channels than in a direction parallel to the direction of extent 9 of the second flow channels. The arrows 10 indicate the possible flow through the second flow channels.

(11) Owing to the significantly larger extent 8 of the cutout 7, a substantially larger amount of second flow channels is intersected by the cutout 7 such that an overflow from the first flow channel formed by the cutout 7 into more second flow channels is possible than in FIG. 1A.

(12) The loss of surface area resulting from the enlarged cutout 7 is compensated for by the surface, over which the flow additionally flows, of the second flow channels, through which the flow additionally passes.

(13) FIG. 2 shows a further view of a corrugated metal foil 2, as has already been shown FIG. 1A. In the perspective view of FIG. 2, the second flow channels 11, which are produced by the corrugation of the metal foil 2, can be clearly seen. The difference with respect to a metal foil having radially aligned flow channels can be seen particularly readily in FIG. 2.

(14) While, in the case of such metal foils, all of the flow channels are acted upon with exhaust gas from the flow channel formed by the central cutout, in the case of the metal foil 2 having the linear second flow channels 11, only the second flow channels 11 are acted upon with exhaust gas from the central cutout 3, these flow channels being intersected by the cutout 3. Accordingly, it is also only possible for a flow to pass through the second flow channels 11 in two of four spatial directions. In the direction transverse to the course of the second flow channels 11, the flow of exhaust gas is prevented by the corrugation of the metal foil 2. This is shown by the crossed-through arrows 12, which show the blocked flow directions. The arrows 13 show the directions along which the exhaust gas can flow.

(15) FIG. 3 shows a honeycomb body 20 which is formed from a plurality of metal foils 6, as can be seen in FIG. 1B.

(16) The honeycomb body 20 is formed from a stack of a plurality of metal foils 6, wherein the metal foils 6 which are directly mutually adjacent are arranged rotated in each case by 90 degrees with respect to one another. This leads to the fact that the second flow channels 22 formed by the corrugation 21 are likewise arranged in layers rotated by 90 degrees with respect to one another. The second flow channels 22 thus lie alternately one above the other in a crosswise manner. The effect advantageously also achieved by this arrangement is that exhaust gas can flow over between the second flow channels 22, which are rotated by 90 degrees with respect to one another, such that a flow can also flow through second flow channels 22 that are not intersected by the central cutout 7. As a result, the portion of the second flow channels 22 through which the flow passes is increased overall, as a result of which the flow action on the individual layers is significantly improved.

(17) In addition, the flow through the second flow channels 22 becomes more turbulent, since a certain portion of the exhaust gas will flow back and forth between crosswise overlapping second flow channels 22. Furthermore, it is advantageous that by dispensing with separating smooth layers between the corrugated metal foils 6, a saving on material is achieved.

(18) FIG. 4 shows an alternative refinement of a honeycomb body 23. In contrast to the honeycomb body 22 in FIG. 3, here the individual corrugated metal foils 6 are separated from one another by smooth layers 24. The second flow channels are thus formed between those respective surfaces of the metal foils 6 which face the smooth layers 24 and the smooth layers 24. The metal foils 6 are aligned in the same direction such that all of the second flow channels run parallel to one another.

(19) The honeycomb body 23 likewise has a diamond-shaped cutout 7. The smooth layers 24 mean that an overflow between second flow channels of different metal foils 6 is not possible. Exhaust gas thus cannot flow through second flow channels that are not intersected by the cutout 7.

(20) This applies at least as long as the smooth layers 24 do not have any openings or guide elements of any other type which allow a targeted overflow between the second flow channels.

(21) FIG. 5, in the left part, shows a metal foil 30 after it has been punched out of a metal strip unwound from a coil. It can be seen that the metal foil has an oval outline and the cutout 31 is also oval. In the middle part, the metal foil 30 is shown in two views, wherein the metal foil 30 already has the corrugation here. It can be seen that the metal foil 30 and also the cutout 31 now have a circular outline. In the right part, a stack of a plurality of the metal foils 30 is shown. In order to prevent the individual metal foils 30 from sliding into one another, they are arranged rotated with respect to one another by at least 5 degrees about the center axis.

(22) The different features of the individual exemplary embodiments can also be combined with one another. The exemplary embodiments in FIGS. 1A to 5 are in particular not of a limiting nature and serve for illustrating the concept of the invention.

(23) Although exemplary embodiments have been discussed in the above description, it should be noted that numerous modifications are possible. Furthermore, it should be noted that the exemplary embodiments are merely examples which are not intended to limit the scope of protection, the applications and the structure in any way. Rather, a person skilled in the art will take from the above description a guideline for implementation of at least one exemplary embodiment, wherein various modifications may be made, in particular with regard to the function and arrangement of the described components, without departing from the scope of protection as can be gathered from the claims and equivalent feature combinations.