EXHAUST AFTERTREATMENT DEVICE

Abstract

An apparatus for treating exhaust gases of an internal combustion engine having at least one main catalytic converter for chemical conversion of at least one exhaust gas component, having a hydrocarbon trap for intermediate storage of hydrocarbons, having a nitrogen oxide adsorber for intermediate storage of nitrogen oxides and having an electrically heatable heated catalytic converter, wherein the abovementioned components are arranged in a spatially delimited flow path and are traversed consecutively.

Claims

1. An apparatus for treating exhaust gases of an internal combustion engine comprising: at least one main catalytic converter for chemical conversion of at least one exhaust gas component; a hydrocarbon trap for intermediate storage of hydrocarbons; a nitrogen oxide adsorber for intermediate storage of nitrogen oxides; and an electrically heatable heated catalytic converter; wherein the at least one main catalytic converter, the hydrocarbon trap, the nitrogen oxide adsorber, and the electrically heatable heated catalytic converter are arranged in a spatially delimited flow path and are traversed consecutively.

2. The apparatus of claim 1, wherein the hydrocarbon trap and the nitrogen oxide adsorber are arranged upstream of the electrically heatable heated catalytic converter in the flow direction of the exhaust gas.

3. The apparatus of claim 1, wherein the hydrocarbon trap and the nitrogen oxide adsorber are each in the form of an individual assembly and are arranged in the flow path consecutively in the flow direction.

4. The apparatus of claim 1, wherein the hydrocarbon trap and the nitrogen oxide adsorber are in the form of a combined assembly.

5. The apparatus of claim 1, the nitrogen oxide adsorber further comprising a passive nitrogen oxide adsorber wherein the passive nitrogen oxide absorber intermediately stores nitrogen oxides from the exhaust gas at a first temperature level, and re-releases the nitrogen oxides into the exhaust gas stream at a second temperature level, the second temperature level higher than the first temperature level.

6. The apparatus of claim 5, wherein the first temperature level is below 200 degrees Celsius.

7. The apparatus of claim 1, wherein the hydrocarbon trap, the nitrogen oxide adsorber and the electrically heatable heated catalytic converter are each formed by a honeycomb traversable along a main flow direction.

8. The apparatus of claim 1, wherein the desorption temperature of the hydrocarbon trap and the nitrogen oxide adsorber is identical to or above the light-off temperature of the main catalytic converter arranged downstream in the flow direction.

9. The apparatus of claim 1, wherein the desorption temperature of the hydrocarbon trap or the nitrogen oxide adsorber is identical to or above the light-off temperature of the main catalytic converter arranged downstream in the flow direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be elucidated in detail hereinbelow on the basis of exemplary embodiments with reference to the drawings. In the drawings:

[0024] FIG. 1 shows a schematic view of an exhaust tract connected downstream of an internal combustion engine with a hydrocarbon trap and a nitrogen oxide adsorber; and

[0025] FIG. 2 shows a further schematic view of an exhaust tract connected downstream of an internal combustion engine with a hydrocarbon trap and a nitrogen oxide adsorber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] 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.

[0027] FIG. 1 shows an internal combustion engine 1. The exhaust gases of the internal combustion engine 1 are passed into the exhaust tract 2 which represents a flow path for the exhaust gas. A hydrocarbon trap 3 and a nitrogen oxide adsorber 4 are arranged within the flow path 2. These may also be arranged in reverse order. Arranged downstream thereof in the flow direction is an electrically heatable heated catalytic converter 5 and downstream thereof at least one main catalytic converter having reference numeral 6 which may be for example an oxidation catalytic converter or an SCR catalytic converter.

[0028] FIG. 2 shows a similar construction as a result of which the employed reference numerals are identical. The difference compared to FIG. 1 is that the hydrocarbon trap 3 and the nitrogen oxide adsorber 4 are in the form of a combination as a common assembly. Here, too, the sequence of the hydrocarbon trap and the nitrogen oxide adsorber may be reversed.

[0029] The exemplary embodiments in FIGS. 1 and 2 are not of a limiting nature and serve to elucidate the inventive concept.

[0030] 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.