Title of Invention	HONEYCOMB BODY WITH FISSURED END SIDES FOR PURIFICATION OF EXHAUST GAS OF AN INTERNAL COMBUSTION ENGINE
Abstract	The invention relates to a wound, lopped and/or coated honeycomb body (1) which is made of sheet steel (2,3). Said honeycomb body comprises a plurality of at least partially structured sheet metal layers (2), whereby the structure thereof forms channels (4) which lead from an inlet front side (5) to an outlet front side (6) of the honeycomb body (1). According to the invention, at least one part of the sheet metal layers (2,3) on the inlet front side (5) and/or the outlet front side (6) comprise recesses (9,10) which are arranged on the edges thereof (7, 8), such that a fissured structure of the inlet front side (5) and/or the outlet front side (6) is produced. As a result, only the smooth sheet steel (3) or only the structured sheet steel (2) or both recesses (9 and/or 10 ) can be provided. Also, at least one part of the sheet steel (2,3) can be made of a porous material, in particular compressed metal fibres (16). Deposition of rust particles (17) on the front sides (5,6) of the honeycomb body (1) is, to a large extent, prevented due to said recesses (9,10).

Title of Invention

HONEYCOMB BODY WITH FISSURED END SIDES FOR PURIFICATION OF EXHAUST GAS OF AN INTERNAL COMBUSTION ENGINE

Abstract

The invention relates to a wound, lopped and/or coated honeycomb body (1) which is made of sheet steel (2,3). Said honeycomb body comprises a plurality of at least partially structured sheet metal layers (2), whereby the structure thereof forms channels (4) which lead from an inlet front side (5) to an outlet front side (6) of the honeycomb body (1). According to the invention, at least one part of the sheet metal layers (2,3) on the inlet front side (5) and/or the outlet front side (6) comprise recesses (9,10) which are arranged on the edges thereof (7, 8), such that a fissured structure of the inlet front side (5) and/or the outlet front side (6) is produced. As a result, only the smooth sheet steel (3) or only the structured sheet steel (2) or both recesses (9 and/or 10 ) can be provided. Also, at least one part of the sheet steel (2,3) can be made of a porous material, in particular compressed metal fibres (16). Deposition of rust particles (17) on the front sides (5,6) of the honeycomb body (1) is, to a large extent, prevented due to said recesses (9,10).

Full Text	WO 2006/092238 PCT/EP2006/001670 Honeycomb body with fissured end sides The present invention relates to a metallic honeycomb body, in particular for the purification of exhaust gas of an internal combustion engine. A particular field of use is the removal of particles from an exhaust gas. A distinction is made primarily between two typical designs of metallic honeycomb bodies. An early design, of which DE 29 02 779 A1 shows typical examples, is the spiral design in which substantially one smooth and one corrugated metal sheet are placed one on top of the other and wound into a spiral shape. In another design, the honeycomb body is constructed from a plurality of alternately arranged smooth and corrugated or differently corrugated metal sheets, with the metal sheets initially forming one or more stacks which are twined with one another. Here, the ends of all the metal sheets are situated at the outside and can be connected to a housing or casing tube, as a result of which several connections are generated which increase the durability of the honeycomb body. Typical examples of this design are described in EP 0 245 737 B1 or WO 90/03220. It has also been long known to equip the metal sheets with additional structures in order to influence the flow and/or to obtain transverse mixing between the individual flow ducts. Typical examples of embodiments of said type are WO 91/01178, WO 91/01807 and WO 90/08249. Finally, there are also honeycomb bodies of conical design, if appropriate also with further additional structures for influencing flow. A honeycomb body of said type is for example described in WO 97/49905. Furthermore, it is also known to leave free a cutout in a honeycomb body for a sensor, in particular for accommodating a lambda probe. An example of this is described in DE 88 16 154 U1. All honeycomb bodies of said type have a plurality of WO 2006/092238 PCT/EP2006/001670 - 2 - at least partially structured metal sheet layers whose structuring forms ducts which lead from an inlet face to an outlet face of the honeycomb body. Metal sheet layers mean the successive layers of the honeycomb body, regardless of whether said metal sheet layers are constructed from one or more separate metal sheets. It is pointed out that it is fundamentally possible to construct a honeycomb body from only a single metal sheet by virtue of for example a part of the sheet metal strip being corrugated and the remaining, smooth part of the sheet metal strip being folded onto said corrugated part by bending. The structure which is formed in this way can be wound in a spiral shape proceeding from the bend line to form a honeycomb body. The next possibility is to use one smooth and one corrugated metal sheet for producing a spiral-shaped wound honeycomb body. Multiple spirals formed from three or more metal sheets are also possible. There are finally a large number of designs which are produced from one or more stacks of alternating smooth and corrugated metal sheets. Honeycomb bodies of said type contain a plurality of metal sheets, with it however not being strictly necessary for the number of the metal sheets and the number of metal sheet layers, which are placed one on top of the other, to be equal. For this reason, a distinction is made in principle between a metal sheet and a metal sheet layer, even if this is often not possible for example in drawings which show only a detail of a honeycomb body. Tests have shown that honeycomb bodies in an exhaust gas flow which contains soot particles can become completely or partially clogged at the end side as a result of deposited soot particles. This adversely affects the normal function, in particular as a soot filter, and/or makes regeneration more difficult. It is therefore an object of the present invention to create WO 2006/092238 PCT/EP2006/001670 - 3 - a honeycomb body in which there is a reduced probability of the deposition of soot particles at the end sides. A honeycomb body as claimed in claim 1 serves to achieve said object. Advantageous refinements and exemplary embodiments are described in the dependent claims. One reason for the deposition of soot particles at the end side of a honeycomb body is that the end faces of the honeycomb body structure are aligned perpendicularly with respect to the flow direction. Soot particles therefore impact almost exactly perpendicularly against the end faces of the honeycomb body. By creating a fissured structure at the inlet end side, two effects are obtained at the same time. On the one hand, purely from a geometric sense, considerable parts of the end face of the honeycomb body are now no longer aligned exactly perpendicularly with respect to the flow direction, and on the other hand, the profile of the flow as it enters the individual ducts is influenced such that only a few particles can impinge frontally against the end face. In addition, any soot depositions which are generated are already situated partially in the interior of the ducts, so that a catalytic reaction can be more easily initiated as a result of contact with catalytically coated duct walls. Any depositions which are generated can therefore be more easily eliminated again. It is fundamentally possible to obtain a fissured structure at the end sides of a honeycomb body by means of very different measures. One possibility is the use of metal sheet layers of different width in a honeycomb body, which can however lead to difficulties in production terms and with regard to reproducibility. It WO 2006/092238 PCT/EP2006/001670 - 4 - is more advantageous if metal sheet layers of identical width can be used. In order to nevertheless generate a fissured end side, at least a part of the metal sheet layers must be provided with end-side cutouts, with the size and the shape of the cutouts being variable within wide limits. For the achievement of the set object, it is fundamentally necessary only for the inlet-side end side of a honeycomb body to be fissured, but it is often undesirable for a honeycomb body to have a certain orientation when it is installed. For this reason, it can be advantageous to design a honeycomb body to be symmetrical so that it can be used in any desired installation direction. A honeycomb body according to the invention is therefore wound, twined and/or layered from metal sheets, having a plurality of at least partially structured metal sheet layers whose structuring forms ducts which lead from an inlet end side to an outlet end side of the honeycomb body. According to the invention, at least a part of the metal sheet layers has cutouts at their edges at the inlet end side and/or at the outlet end side, so as to generate a fissured structure of the inlet end side and/or of the outlet end side. Honeycomb bodies are typically constructed from alternating layers of substantially smooth and corrugated metal sheets, with it being possible according to the invention for only the smooth metal sheets, only the corrugated metal sheets or else both to have cutouts. In the case of honeycomb bodies which are designed as particle filters, in particular for the removal of soot particles, a part of the metal sheet layers is often composed of porous material, in particular of WO 2006/092238 PCT/EP2006/001670 —6- sides. The connection is preferably applied to honeycomb bodies which are formed from one or more stacks of metal sheets, with the metal sheets of each stack having a predefined length and a predefined width, where the length is greater than the width, and with the metal sheets of each stack in each case having several cutouts over the length. The cutouts are therefore situated at the longitudinal sides of the metal sheets, while the width sides are preferably, but not necessarily, formed without cutouts. Since, during the production of a honeycomb body, the width sides must typically be connected to the casing tube of said honeycomb body, cutouts are not necessarily advantageous here. According to one preferred embodiment of the invention, the cutouts have rounded boundary lines, thereby largely avoiding notching effects, that is to say the tearing of the metal sheet edges in the region of the cutouts. Cutouts are particularly preferably in the form of circular sections, preferably in each case a semicircle or smaller circular section. Since particle filters are for example produced from holed metal sheet layers, it is even possible if appropriate for the machines which are used in any case to generate holes in the metal sheet layers to also be used for generating the cutouts at the edges of the metal sheets. It is even possible to provide wide sheet metal strips uniformly with holes, and to thereafter cut the sheet metal strips to the desired width, wherein the cutting lines should preferably run through the center of rows of holes. In order to obtain the desired effect of avoiding soot WO 2006/092238 PCT/EP2006/001670 -7- depositions at the end sides, it is advantageous if more than 80% of the ducts end in the region of at least one cutout at at least one end side of a honeycomb body according to the invention. This should particularly preferably be even more than 90% of the ducts. It can be ensured in this way that even local accumulations of soot at the end side are avoided. Also proposed is a honeycomb body which has at least one cavity at the inlet end side. Said cavity is preferably arranged centrally and has in particular a conically narrowing section. One advantage of a design of said type is that ducts of different length are formed, which ducts result in pressure differences in relation to adjacent ducts. This promotes a mixture of partial exhaust gas flows within the honeycomb body. Also preferable is a design of the honeycomb body in which a part of the ducts is closed off close to the outlet end side. Such a closure of the ducts can be carried out by pressing together the duct walls and/or by providing a blocking element. It is particularly preferable for at least a part of the ducts which are arranged at the outer edge of the honeycomb body to be closed off, so that a flow which is forced within the honeycomb body enters through the cutouts into the inner partial volume. According to another refinement of the honeycomb body, said honeycomb body has a plurality of partial volumes which have a different number of ducts per unit of cross-sectional area from one another. Preferable here (for example for cylindrical designs of the honeycomb body) is a coaxial arrangement of two partial volumes. The field of use of honeycomb bodies according to the invention is primarily the purification of the exhaust WO 2006/092238 PCT/EP2006/001670 - 9 - constructed from a structured metal sheet 2 and a smooth metal sheet 3, with the structured metal sheet 2 having cutouts 9 at both longitudinal-side edges. The smooth metal sheet 3, with the width B and the length L, also has several cutouts 10 over the length L at its end-side edges 8. The boundary lines 12 of said cutouts 10 are rounded, so that the cutouts 10 have approximately the shape of circular segments. As the metal sheets 2, 3 are wound further, the ducts 4 of the honeycomb body 1 are formed, with sufficient end-side connecting points 11 between the smooth and corrugated metal sheet layers 2, 3 still being generated despite the cutouts 9, 10. The finished honeycomb body later has a fissured inlet end side 5 and a fissured outlet end side 6, but it is nevertheless possible if required for sufficient connecting points 11 to be brazed to one another by means of conventional methods. Figure 2 shows a corrugated metal sheet 2, with the width B, which is suitable for constructing a honeycomb body according to the invention. In this exemplary embodiment, only the inlet end side 5 has cutouts 9, while the outlet end side 6 has an edge strip 15 without cutouts. The end-side edge 7 of the corrugated metal sheet 2 has cutouts 9 with circular-section- shaped boundary lines 12. In addition, openings 13 are provided further in the interior of the structured metal sheet 2. For the present invention, the exact shape of the openings 13 and of the cutouts 9 is arbitrary, but it can be advantageous to select the shapes such that the projection of said openings or cutouts on the central plane of the structured metal sheet 2 is circular or circular-segment-shaped. Figure 3 shows, in a schematic perspective illustration, the typical conditions in a particle filter in which the exhaust gas is deflected through a WO 2006/092238 PCT/EP2006/001670 - 10 - porous, smooth layer 3 made from metallic fibers 16 by deflecting structures 14. The flow paths 19 are indicated by arrows. Soot particles 17 are deflected through openings 13 and by the deflecting structures 14 to the porous metal sheet layer 3, are held there and are converted. In this exemplary embodiment, too, the accumulation of soot particles 17 on the end-side metal sheet edge 7 of the structured metal sheet 2 or on the end-side metal sheet edge 8 of the smooth metal sheet 3 can be reduced by means of cutouts 10 in the smooth metal sheet 3. Here, too, the boundary line 12 of the cutout 10 has approximately the shape of a circular section. It can be seen that the cutout 10 influences the flow conditions as the flow enters into the adjoining ducts 4, and an accumulation of particles is therefore less likely. Figure 4 schematically shows different possibilities for the design of the edges of a metal sheet having cutouts. In the present exemplary embodiment, an end- side metal sheet edge 8 of the smooth metal sheet 3 is provided with individual cutouts 10, while the opposite metal sheet edge has the shape of a corrugated line 18. A corrugated line 18 should also be considered within the context of the present invention as a metal sheet edge having cutouts. A typical installation situation of a honeycomb body 1 according to the invention is illustrated in figure 5. Exhaust gases pass from an internal combustion engine 20 into an exhaust system 21 which has the honeycomb body 1 according to the invention and if appropriate further components, in particular an oxidation catalytic converter 22 connected downstream. Figure 6 shows a honeycomb body 1 placed in a housing 23, which honeycomb body 1 has a centrally-arranged WO 2006/092238 PCT/EP2006/001670 - 11 - cavity 25 at the inlet end side 5. Said cavity 25 has a conically narrowing section. The ducts 4, which are of different length on account of the cavity 25, create pressure differences, so that the exhaust gas which enters in the illustrated flow direction 24 is deflected in the interior of the honeycomb body as is schematically illustrated by the arrows. In order to intensify this effect, a part of the ducts 4 is additionally closed off close to the outlet end side 6 by means of a ring-shaped blocking element 26. Figure 7 illustrates two honeycomb bodies 1 in one housing 23, which honeycomb bodies 1 have in each case two concentric partial volumes 27, 28 which have a different number of ducts 4 per unit of cross-sectional area from one another. Here, the honeycomb bodies 1 are spaced apart from one another with a gap 29 for example of less than 10 mm, and have an inverse arrangement of the partial volumes 27, 28, so that the partial volume 27, with a high duct density, of the first honeycomb body, and the partial volume 28, with the relatively low duct density, of the second honeycomb body are situated opposite one another (as viewed in the flow direction 24) . Here, the illustrated variant is preferred, in which the first honeycomb body has a first partial volume 27, with a high duct density, at the outside. The first partial volume 27 has in particular a duct density which is greater, at least by a factor of 1.5, than that of the second partial volume 28. The first partial volume preferably has a duct density in the region of at least 800 cpsi (cells per square inch; 1 cpsi corresponds approximately to 6.4516 cells per square centimeter). It is additionally advantageous, with regard to the considerable thermal and dynamic loadings of the honeycomb body 1 in the exhaust system of a vehicle, WO 2006/092238 PCT/EP2006/001670 - 12 - for at least one support element 3 0 to be provided at least partially between the partial volumes 27, 28. In the concentric arrangement illustrated here, said support element 3 0 can for example be a tube section. The present invention serves to further improve metallic honeycomb bodies when used as exhaust gas purification components, in particular for removing harmful particles from an exhaust gas. The invention prevents or reduces the deposition of particles, in particular soot, at the end sides of a honeycomb body. WO2006/092238 PCT/EP2006/001670 - 13 - List of reference symbols 1 Honeycomb body 2 Structured metal sheet 3 Substantially smooth metal sheet 4 Duct 5 Inlet end side 6 Outlet end side 7 End-side metal sheet edge of the structured metal sheet 8 End-side metal sheet edge of the substantially smooth metal sheet 9 Cutout in corrugated metal sheet 10 Cutout in smooth metal sheet 11 Connecting point 12 Boundary line 13 Opening 14 Deflecting structure 15 Edge strips 16 Metal fibers 17 Soot particles 18 Corrugation line 19 Flow paths 20 Internal combustion engine 21 Exhaust gas purification system 22 Catalytic converter 23 Housing 24 Flow direction 25 Cavity 26 Blocking element 27 First partial volume 28 Second partial volume 29 Gap 30 Support element L Length B Width WO 2006/092238 PCT/EP2006/001670 - 14 - Patent claims 1. A honeycomb body (1) which is wound, twined and/or layered from metal sheets (2,3), having a plurality of at least partially structured metal sheet layers (2) whose structuring forms ducts (4) which lead from an inlet end side (5) to an outlet end side (6) of the honeycomb body (1), characterized in that at least a part of the metal sheet layers (2, 3) has cutouts (9, 10) at their edges (7, 8) at the inlet end side (5) and/or at the outlet end side (6) , so as to generate a fissured structure of the inlet end side (5) and of the outlet end side (6), respectively. 2. The honeycomb body (1) as claimed in claim 1, which honeycomb body (1) is constructed from alternating layers of substantially smooth (2) and corrugated (3) metal sheets, characterized in that only the smooth metal sheets (2) have cutouts. 3. The honeycomb body (1) as claimed in claim 1, which honeycomb body (1) is constructed from alternating layers of substantially smooth (2) and corrugated (3) metal sheets, characterized in that only the corrugated metal sheets (3) have cutouts. 4. The honeycomb body as claimed in claim 1, 2 or 3, characterized in that at least a part of the metal sheets (2, 3)' is composed of porous material, in particular of compressed metal fibers (16). 5. The honeycomb body as claimed in one of the preceding claims, characterized in that the metal sheets (2,3) have sections at their end-side edges (7,8) without cutouts (9,10),which sections are long enough and frequent enough that WO 2006/092238 PCT/EP2006/001670 - 15 - a plurality of contact points (11) are provided statistically distributed between the foremost and rearmost edges (7, 8) of the metal sheet layers (2, 3) . 6. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that the honeycomb body (1) is formed from one or more stacks of metal sheets (2, 3), with the metal sheets (2, 3) of each stack having a length (L) and a width (B) , where L > B, and with the metal sheets (2, 3) of each stack in each case having a plurality of cutouts (9, 10) over the length (L). 7. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that the cutouts (9, 10) have rounded boundary lines (12). 8. The honeycomb body as claimed in one of the preceding claims, characterized in that the cutouts (9, 10) have the shape of circular sections, preferably semicircles or smaller circular sections. 9. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that more than 80% of the ducts (4), preferably more than 90% of the ducts (4) , end in the region of at least one cutout (9, 10) at at least one end side (5, 6) . 10. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that it is part of an exhaust gas purification system (21) of an internal combustion engine (20), in particular of a diesel engine, and contributes to the removal of soot particles (17) from the exhaust gas of the internal combustion engine (20). WO 2006/092238 PCT/EP2006/001670 - 16 - 11. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that said honeycomb body (1) has additional openings (13) in the metal sheets (2, 3) and/or deflecting structures (14) in the ducts (4). 12. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that said honeycomb body (1) has at least one cavity (25) at the inlet end side (5) . 13. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that a part of the ducts (4) is closed off close to the outlet end side (6) . 14. The honeycomb body (1) as claimed in one of the preceding claims, characterized in that said honeycomb body (1) has a plurality of partial volumes (27,28) which have a different number of ducts (4) per unit of cross-sectional area from one another. Date the 13th day of August, 2007 The invention relates to a wound, lopped and/or coated honeycomb body (1) which is made of sheet steel (2,3). Said honeycomb body comprises a plurality of at least partially structured sheet metal layers (2), whereby the structure thereof forms channels (4) which lead from an inlet front side (5) to an outlet front side (6) of the honeycomb body (1). According to the invention, at least one part of the sheet metal layers (2,3) on the inlet front side (5) and/or the outlet front side (6) comprise recesses (9,10) which are arranged on the edges thereof (7, 8), such that a fissured structure of the inlet front side (5) and/or the outlet front side (6) is produced. As a result, only the smooth sheet steel (3) or only the structured sheet steel (2) or both recesses (9 and/or 10 ) can be provided. Also, at least one part of the sheet steel (2,3) can be made of a porous material, in particular compressed metal fibres (16). Deposition of rust particles (17) on the front sides (5,6) of the honeycomb body (1) is, to a large extent, prevented due to said recesses (9,10).

Full Text

WO 2006/092238 PCT/EP2006/001670
Honeycomb body with fissured end sides
The present invention relates to a metallic honeycomb
body, in particular for the purification of exhaust gas
of an internal combustion engine. A particular field of
use is the removal of particles from an exhaust gas.
A distinction is made primarily between two typical
designs of metallic honeycomb bodies. An early design,
of which DE 29 02 779 A1 shows typical examples, is the
spiral design in which substantially one smooth and one
corrugated metal sheet are placed one on top of the
other and wound into a spiral shape. In another design,
the honeycomb body is constructed from a plurality of
alternately arranged smooth and corrugated or
differently corrugated metal sheets, with the metal
sheets initially forming one or more stacks which are
twined with one another. Here, the ends of all the
metal sheets are situated at the outside and can be
connected to a housing or casing tube, as a result of
which several connections are generated which increase
the durability of the honeycomb body. Typical examples
of this design are described in EP 0 245 737 B1 or WO
90/03220. It has also been long known to equip the
metal sheets with additional structures in order to
influence the flow and/or to obtain transverse mixing
between the individual flow ducts. Typical examples of
embodiments of said type are WO 91/01178, WO 91/01807
and WO 90/08249. Finally, there are also honeycomb
bodies of conical design, if appropriate also with
further additional structures for influencing flow. A
honeycomb body of said type is for example described in
WO 97/49905. Furthermore, it is also known to leave
free a cutout in a honeycomb body for a sensor, in
particular for accommodating a lambda probe. An example
of this is described in DE 88 16 154 U1.
All honeycomb bodies of said type have a plurality of

WO 2006/092238 PCT/EP2006/001670
- 2 -
at least partially structured metal sheet layers whose
structuring forms ducts which lead from an inlet face
to an outlet face of the honeycomb body. Metal sheet
layers mean the successive layers of the honeycomb
body, regardless of whether said metal sheet layers are
constructed from one or more separate metal sheets. It
is pointed out that it is fundamentally possible to
construct a honeycomb body from only a single metal
sheet by virtue of for example a part of the sheet
metal strip being corrugated and the remaining, smooth
part of the sheet metal strip being folded onto said
corrugated part by bending. The structure which is
formed in this way can be wound in a spiral shape
proceeding from the bend line to form a honeycomb body.
The next possibility is to use one smooth and one
corrugated metal sheet for producing a spiral-shaped
wound honeycomb body. Multiple spirals formed from
three or more metal sheets are also possible. There are
finally a large number of designs which are produced
from one or more stacks of alternating smooth and
corrugated metal sheets. Honeycomb bodies of said type
contain a plurality of metal sheets, with it however
not being strictly necessary for the number of the
metal sheets and the number of metal sheet layers,
which are placed one on top of the other, to be equal.
For this reason, a distinction is made in principle
between a metal sheet and a metal sheet layer, even if
this is often not possible for example in drawings
which show only a detail of a honeycomb body.
Tests have shown that honeycomb bodies in an exhaust
gas flow which contains soot particles can become
completely or partially clogged at the end side as a
result of deposited soot particles. This adversely
affects the normal function, in particular as a soot
filter, and/or makes regeneration more difficult. It is
therefore an object of the present invention to create

WO 2006/092238 PCT/EP2006/001670
- 3 -
a honeycomb body in which there is a reduced
probability of the deposition of soot particles at the
end sides.
A honeycomb body as claimed in claim 1 serves to
achieve said object. Advantageous refinements and
exemplary embodiments are described in the dependent
claims.
One reason for the deposition of soot particles at the
end side of a honeycomb body is that the end faces of
the honeycomb body structure are aligned
perpendicularly with respect to the flow direction.
Soot particles therefore impact almost exactly
perpendicularly against the end faces of the honeycomb
body. By creating a fissured structure at the inlet end
side, two effects are obtained at the same time. On the
one hand, purely from a geometric sense, considerable
parts of the end face of the honeycomb body are now no
longer aligned exactly perpendicularly with respect to
the flow direction, and on the other hand, the profile
of the flow as it enters the individual ducts is
influenced such that only a few particles can impinge
frontally against the end face. In addition, any soot
depositions which are generated are already situated
partially in the interior of the ducts, so that a
catalytic reaction can be more easily initiated as a
result of contact with catalytically coated duct walls.
Any depositions which are generated can therefore be
more easily eliminated again.
It is fundamentally possible to obtain a fissured
structure at the end sides of a honeycomb body by means
of very different measures. One possibility is the use
of metal sheet layers of different width in a honeycomb
body, which can however lead to difficulties in
production terms and with regard to reproducibility. It

WO 2006/092238 PCT/EP2006/001670
- 4 -
is more advantageous if metal sheet layers of identical
width can be used. In order to nevertheless generate a
fissured end side, at least a part of the metal sheet
layers must be provided with end-side cutouts, with the
size and the shape of the cutouts being variable within
wide limits. For the achievement of the set object, it
is fundamentally necessary only for the inlet-side end
side of a honeycomb body to be fissured, but it is
often undesirable for a honeycomb body to have a
certain orientation when it is installed. For this
reason, it can be advantageous to design a honeycomb
body to be symmetrical so that it can be used in any
desired installation direction.
A honeycomb body according to the invention is
therefore wound, twined and/or layered from metal
sheets, having a plurality of at least partially
structured metal sheet layers whose structuring forms
ducts which lead from an inlet end side to an outlet
end side of the honeycomb body. According to the
invention, at least a part of the metal sheet layers
has cutouts at their edges at the inlet end side and/or
at the outlet end side, so as to generate a fissured
structure of the inlet end side and/or of the outlet
end side.
Honeycomb bodies are typically constructed from
alternating layers of substantially smooth and
corrugated metal sheets, with it being possible
according to the invention for only the smooth metal
sheets, only the corrugated metal sheets or else both
to have cutouts.
In the case of honeycomb bodies which are designed as
particle filters, in particular for the removal of soot
particles, a part of the metal sheet layers is often
composed of porous material, in particular of

WO 2006/092238 PCT/EP2006/001670
—6-
sides.
The connection is preferably applied to honeycomb
bodies which are formed from one or more stacks of
metal sheets, with the metal sheets of each stack
having a predefined length and a predefined width,
where the length is greater than the width, and with
the metal sheets of each stack in each case having
several cutouts over the length. The cutouts are
therefore situated at the longitudinal sides of the
metal sheets, while the width sides are preferably, but
not necessarily, formed without cutouts. Since, during
the production of a honeycomb body, the width sides
must typically be connected to the casing tube of said
honeycomb body, cutouts are not necessarily
advantageous here.
According to one preferred embodiment of the invention,
the cutouts have rounded boundary lines, thereby
largely avoiding notching effects, that is to say the
tearing of the metal sheet edges in the region of the
cutouts.
Cutouts are particularly preferably in the form of
circular sections, preferably in each case a semicircle
or smaller circular section. Since particle filters are
for example produced from holed metal sheet layers, it
is even possible if appropriate for the machines which
are used in any case to generate holes in the metal
sheet layers to also be used for generating the cutouts
at the edges of the metal sheets. It is even possible
to provide wide sheet metal strips uniformly with
holes, and to thereafter cut the sheet metal strips to
the desired width, wherein the cutting lines should
preferably run through the center of rows of holes.
In order to obtain the desired effect of avoiding soot

WO 2006/092238 PCT/EP2006/001670
-7-
depositions at the end sides, it is advantageous if
more than 80% of the ducts end in the region of at
least one cutout at at least one end side of a
honeycomb body according to the invention. This should
particularly preferably be even more than 90% of the
ducts. It can be ensured in this way that even local
accumulations of soot at the end side are avoided.
Also proposed is a honeycomb body which has at least
one cavity at the inlet end side. Said cavity is
preferably arranged centrally and has in particular a
conically narrowing section. One advantage of a design
of said type is that ducts of different length are
formed, which ducts result in pressure differences in
relation to adjacent ducts. This promotes a mixture of
partial exhaust gas flows within the honeycomb body.
Also preferable is a design of the honeycomb body in
which a part of the ducts is closed off close to the
outlet end side. Such a closure of the ducts can be
carried out by pressing together the duct walls and/or
by providing a blocking element. It is particularly
preferable for at least a part of the ducts which are
arranged at the outer edge of the honeycomb body to be
closed off, so that a flow which is forced within the
honeycomb body enters through the cutouts into the
inner partial volume.
According to another refinement of the honeycomb body,
said honeycomb body has a plurality of partial volumes
which have a different number of ducts per unit of
cross-sectional area from one another. Preferable here
(for example for cylindrical designs of the honeycomb
body) is a coaxial arrangement of two partial volumes.
The field of use of honeycomb bodies according to the
invention is primarily the purification of the exhaust

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constructed from a structured metal sheet 2 and a
smooth metal sheet 3, with the structured metal sheet 2
having cutouts 9 at both longitudinal-side edges. The
smooth metal sheet 3, with the width B and the length
L, also has several cutouts 10 over the length L at its
end-side edges 8. The boundary lines 12 of said cutouts
10 are rounded, so that the cutouts 10 have
approximately the shape of circular segments. As the
metal sheets 2, 3 are wound further, the ducts 4 of the
honeycomb body 1 are formed, with sufficient end-side
connecting points 11 between the smooth and corrugated
metal sheet layers 2, 3 still being generated despite
the cutouts 9, 10. The finished honeycomb body later
has a fissured inlet end side 5 and a fissured outlet
end side 6, but it is nevertheless possible if required
for sufficient connecting points 11 to be brazed to one
another by means of conventional methods.
Figure 2 shows a corrugated metal sheet 2, with the
width B, which is suitable for constructing a honeycomb
body according to the invention. In this exemplary
embodiment, only the inlet end side 5 has cutouts 9,
while the outlet end side 6 has an edge strip 15
without cutouts. The end-side edge 7 of the corrugated
metal sheet 2 has cutouts 9 with circular-section-
shaped boundary lines 12. In addition, openings 13 are
provided further in the interior of the structured
metal sheet 2. For the present invention, the exact
shape of the openings 13 and of the cutouts 9 is
arbitrary, but it can be advantageous to select the
shapes such that the projection of said openings or
cutouts on the central plane of the structured metal
sheet 2 is circular or circular-segment-shaped.
Figure 3 shows, in a schematic perspective
illustration, the typical conditions in a particle
filter in which the exhaust gas is deflected through a

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porous, smooth layer 3 made from metallic fibers 16 by
deflecting structures 14. The flow paths 19 are
indicated by arrows. Soot particles 17 are deflected
through openings 13 and by the deflecting structures 14
to the porous metal sheet layer 3, are held there and
are converted. In this exemplary embodiment, too, the
accumulation of soot particles 17 on the end-side metal
sheet edge 7 of the structured metal sheet 2 or on the
end-side metal sheet edge 8 of the smooth metal sheet 3
can be reduced by means of cutouts 10 in the smooth
metal sheet 3. Here, too, the boundary line 12 of the
cutout 10 has approximately the shape of a circular
section. It can be seen that the cutout 10 influences
the flow conditions as the flow enters into the
adjoining ducts 4, and an accumulation of particles is
therefore less likely.
Figure 4 schematically shows different possibilities
for the design of the edges of a metal sheet having
cutouts. In the present exemplary embodiment, an end-
side metal sheet edge 8 of the smooth metal sheet 3 is
provided with individual cutouts 10, while the opposite
metal sheet edge has the shape of a corrugated line 18.
A corrugated line 18 should also be considered within
the context of the present invention as a metal sheet
edge having cutouts.
A typical installation situation of a honeycomb body 1
according to the invention is illustrated in figure 5.
Exhaust gases pass from an internal combustion engine
20 into an exhaust system 21 which has the honeycomb
body 1 according to the invention and if appropriate
further components, in particular an oxidation
catalytic converter 22 connected downstream.
Figure 6 shows a honeycomb body 1 placed in a housing
23, which honeycomb body 1 has a centrally-arranged

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cavity 25 at the inlet end side 5. Said cavity 25 has a
conically narrowing section. The ducts 4, which are of
different length on account of the cavity 25, create
pressure differences, so that the exhaust gas which
enters in the illustrated flow direction 24 is
deflected in the interior of the honeycomb body as is
schematically illustrated by the arrows. In order to
intensify this effect, a part of the ducts 4 is
additionally closed off close to the outlet end side 6
by means of a ring-shaped blocking element 26.
Figure 7 illustrates two honeycomb bodies 1 in one
housing 23, which honeycomb bodies 1 have in each case
two concentric partial volumes 27, 28 which have a
different number of ducts 4 per unit of cross-sectional
area from one another. Here, the honeycomb bodies 1 are
spaced apart from one another with a gap 29 for example
of less than 10 mm, and have an inverse arrangement of
the partial volumes 27, 28, so that the partial volume
27, with a high duct density, of the first honeycomb
body, and the partial volume 28, with the relatively
low duct density, of the second honeycomb body are
situated opposite one another (as viewed in the flow
direction 24) . Here, the illustrated variant is
preferred, in which the first honeycomb body has a
first partial volume 27, with a high duct density, at
the outside. The first partial volume 27 has in
particular a duct density which is greater, at least by
a factor of 1.5, than that of the second partial volume
28. The first partial volume preferably has a duct
density in the region of at least 800 cpsi (cells per
square inch; 1 cpsi corresponds approximately to 6.4516
cells per square centimeter).
It is additionally advantageous, with regard to the
considerable thermal and dynamic loadings of the
honeycomb body 1 in the exhaust system of a vehicle,

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for at least one support element 3 0 to be provided at
least partially between the partial volumes 27, 28. In
the concentric arrangement illustrated here, said
support element 3 0 can for example be a tube section.
The present invention serves to further improve
metallic honeycomb bodies when used as exhaust gas
purification components, in particular for removing
harmful particles from an exhaust gas. The invention
prevents or reduces the deposition of particles, in
particular soot, at the end sides of a honeycomb body.

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List of reference symbols
1 Honeycomb body
2 Structured metal sheet
3 Substantially smooth metal sheet
4 Duct
5 Inlet end side
6 Outlet end side
7 End-side metal sheet edge of the structured metal
sheet
8 End-side metal sheet edge of the substantially
smooth metal sheet
9 Cutout in corrugated metal sheet
10 Cutout in smooth metal sheet
11 Connecting point
12 Boundary line
13 Opening
14 Deflecting structure
15 Edge strips
16 Metal fibers
17 Soot particles
18 Corrugation line
19 Flow paths
20 Internal combustion engine
21 Exhaust gas purification system
22 Catalytic converter
23 Housing

24 Flow direction
25 Cavity
26 Blocking element
27 First partial volume
28 Second partial volume
29 Gap
30 Support element
L Length
B Width

WO 2006/092238 PCT/EP2006/001670
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Patent claims
1. A honeycomb body (1) which is wound, twined and/or
layered from metal sheets (2,3), having a
plurality of at least partially structured metal
sheet layers (2) whose structuring forms ducts
(4) which lead from an inlet end side (5) to an
outlet end side (6) of the honeycomb body (1),
characterized in that at least a part of the metal
sheet layers (2, 3) has cutouts (9, 10) at their
edges (7, 8) at the inlet end side (5) and/or at
the outlet end side (6) , so as to generate a
fissured structure of the inlet end side (5) and
of the outlet end side (6), respectively.
2. The honeycomb body (1) as claimed in claim 1,
which honeycomb body (1) is constructed from
alternating layers of substantially smooth (2) and
corrugated (3) metal sheets, characterized in that
only the smooth metal sheets (2) have cutouts.
3. The honeycomb body (1) as claimed in claim 1,
which honeycomb body (1) is constructed from
alternating layers of substantially smooth (2) and
corrugated (3) metal sheets, characterized in that
only the corrugated metal sheets (3) have cutouts.
4. The honeycomb body as claimed in claim 1, 2 or 3,
characterized in that at least a part of the metal
sheets (2, 3)' is composed of porous material, in
particular of compressed metal fibers (16).
5. The honeycomb body as claimed in one of the
preceding claims, characterized in that the metal
sheets (2,3) have sections at their end-side
edges (7,8) without cutouts (9,10),which
sections are long enough and frequent enough that

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a plurality of contact points (11) are provided
statistically distributed between the foremost and
rearmost edges (7, 8) of the metal sheet layers
(2, 3) .
6. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that the
honeycomb body (1) is formed from one or more
stacks of metal sheets (2, 3), with the metal
sheets (2, 3) of each stack having a length (L)
and a width (B) , where L > B, and with the metal
sheets (2, 3) of each stack in each case having a
plurality of cutouts (9, 10) over the length (L).
7. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that the
cutouts (9, 10) have rounded boundary lines (12).
8. The honeycomb body as claimed in one of the
preceding claims, characterized in that the
cutouts (9, 10) have the shape of circular
sections, preferably semicircles or smaller
circular sections.
9. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that more than
80% of the ducts (4), preferably more than 90% of
the ducts (4) , end in the region of at least one
cutout (9, 10) at at least one end side (5, 6) .
10. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that it is part
of an exhaust gas purification system (21) of an
internal combustion engine (20), in particular of
a diesel engine, and contributes to the removal of
soot particles (17) from the exhaust gas of the
internal combustion engine (20).

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11. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that said
honeycomb body (1) has additional openings (13) in
the metal sheets (2, 3) and/or deflecting
structures (14) in the ducts (4).
12. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that said
honeycomb body (1) has at least one cavity (25) at
the inlet end side (5) .
13. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that a part of
the ducts (4) is closed off close to the outlet
end side (6) .
14. The honeycomb body (1) as claimed in one of the
preceding claims, characterized in that said
honeycomb body (1) has a plurality of partial
volumes (27,28) which have a different number of
ducts (4) per unit of cross-sectional area from
one another.
Date the 13th day of August, 2007

The invention relates to a wound, lopped and/or coated honeycomb body (1)
which is made of sheet steel (2,3). Said honeycomb body comprises a plurality of
at least partially structured sheet metal layers (2), whereby the structure thereof
forms channels (4) which lead from an inlet front side (5) to an outlet front side
(6) of the honeycomb body (1). According to the invention, at least one part of
the sheet metal layers (2,3) on the inlet front side (5) and/or the outlet front
side (6) comprise recesses (9,10) which are arranged on the edges thereof (7,
8), such that a fissured structure of the inlet front side (5) and/or the outlet front
side (6) is produced. As a result, only the smooth sheet steel (3) or only the
structured sheet steel (2) or both recesses (9 and/or 10 ) can be provided. Also,
at least one part of the sheet steel (2,3) can be made of a porous material, in
particular compressed metal fibres (16). Deposition of rust particles (17) on the
front sides (5,6) of the honeycomb body (1) is, to a large extent, prevented due
to said recesses (9,10).

HONEYCOMB BODY WITH FISSURED END SIDES FOR PURIFICATION OF EXHAUST GAS OF AN INTERNAL COMBUSTION ENGINE

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