EXHAUST GAS AFTERTREATMENT DEVICE

Abstract

A device for exhaust-gas aftertreatment, such as an annular catalytic converter, having a first, tubular flow path, having a diverting chamber and having a second, annular flow path, wherein the tubular flow path is delimited outwardly in the radial direction by an inner pipe and the second, annular flow path is delimited inwardly in the radial direction by the inner pipe and outwardly in the radial direction by an outer pipe, and the diverting chamber is designed to divert the exhaust-gas flow from the tubular flow path (8) into the annular flow path, wherein the annular catalytic converter has at least one annular substrate body which has a catalytically active coating applied to it and which is arranged in the annular flow path.

Claims

1. A device for exhaust-gas aftertreatment comprising: an inner pipe; a tubular flow path is delimited outwardly in the radial direction by the inner pipe; an outer pipe; an annular flow path is delimited inwardly in the radial direction by the inner pipe and outwardly in the radial direction by the outer pipe; a diverting chamber which diverts the exhaust-gas flow from the tubular flow path into the annular flow path; at least one annular substrate body arranged in the annular flow path; and a catalytically active coating applied to the at least one annular substrate body.

2. The device of claim 1, the substrate body further comprising: a multiplicity of metal foils; and a multiplicity of flow channels formed between the multiplicity of metal foils; wherein flow passes through the multiplicity of flow channels in the flow direction.

3. The device of claim 2, at least some of the multiplicity of metal foils further comprising cutouts, forming flow transfer passages between the multiplicity of flow channels which are mutually adjacent to one another.

4. The device of claim 3, wherein the cutouts formed in the multiplicity of metal foils are arranged at the end region of the substrate body which faces toward the diverting chamber.

5. The device of claim 1, the substrate body further comprising at least partially structured metal foils and smooth metal foils, which are stacked one on top of the other and wound up.

6. The device of claim 1, further comprising an electrically heatable heating disk arranged in the annular flow path.

7. The device of claim 6, wherein the electrically heatable heating disk is positioned upstream of the substrate body in the flow direction of the exhaust gas.

8. The device of claim 1, the outer pipe further comprising a heating element.

9. The device of claim 8, the heating element further comprising a heating coil which is wound around the outer pipe.

10. The device of claim 8, the heating element further comprising a multiplicity of heating devices which are arranged so as to be distributed along the circumference of the outer pipe.

11. The device of claim 1, further comprising a jacket in which the outer pipe is received, the jacket having a heating element.

12. The device of claim 11, the heating element further comprising a heating coil which is wound around the jacket.

13. The device of claim 11, the heating element further comprising a multiplicity of heating devices which are arranged so as to be distributed along the circumference of the jacket.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention will be discussed in more detail below on the basis of exemplary embodiments with reference to the drawings. In the drawings:

[0026] FIG. 1 shows a sectional view through an annular catalytic converter, wherein the substrate body has a perforation in the annular flow path at its inflow side;

[0027] FIG. 2 shows a sectional view through an annular catalytic converter, wherein a heating disk is positioned upstream of the annular substrate body as viewed in the flow direction, and

[0028] FIG. 3 shows a sectional view through an annular catalytic converter, wherein a heating coil is wound around the outer pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0030] FIG. 1 shows a sectional view through an annular catalytic converter 1, wherein the substrate body 3 arranged in the annular flow path 2 has a plurality of cutouts 5 at its gas inflow side 4. Because of the cutouts 5, which are for example made in the individual metal foils from which the substrate body 3 is formed, the heat capacity of the substrate body 3 is reduced, which allows faster heating and thus makes it possible for the light-off temperature to be reached more quickly.

[0031] FIG. 2 shows an annular catalytic converter 1 as has already been shown in FIG. 1 In this exemplary embodiment, an electrically heatable heating disk 7 is positioned upstream of the substrate body 6.

[0032] The heating disk 7 may be arranged entirely in the annular flow path 2, or else somewhat upstream thereof in the diverting chamber, and, by way of its own structure, lengthen both the tubular flow path 8 and the annular flow path 2.

[0033] The heating disk 7 may be connected to a voltage source via an electrical contact arrangement (not shown) and may thus be electrically heated.

[0034] FIG. 3 shows an annular catalytic converter 1 as in the preceding FIGS. 1 and 2, wherein a heating coil 9 has now been wound around the outer pipe or the outer jacket of the annular catalytic converter 1. This heating coil 9 may for example be formed by a heating conductor.

[0035] As shown in FIG. 3, the heating coil 9 may be arranged along the entire axial extent of the annular flow path 2, such that heating from the outside is achieved over the entire length. Alternatively, only a partial region may be enwound by the heating coil. In an embodiment, the gas inlet side of the substrate body 3 is enwound in such a case.

[0036] The different features of the individual exemplary embodiments may also be combined with one another. Accordingly, the features shown in FIGS. 1, 2 and 3 may also be combined in a common exemplary embodiment, such that the heating coil on the outer pipe interacts with the electrical heating disk and the cutouts in the metal foils of the substrate body. Any other combination of the individual exemplary embodiments is also possible according to the invention.

[0037] The exemplary embodiments in FIGS. 1 to 3 are not of a limiting nature and serve for illustrating the concept of the invention.

[0038] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.