EXHAUST GAS AFTERTREATMENT DEVICE

Abstract

A device for the aftertreatment of exhaust gases of an internal combustion engine, with an exhaust gas line, which is configured to feed the exhaust gas expelled from the internal combustion engine to at least one component for exhaust gas aftertreatment. The at least one adsorber for the temporary storage of hydrocarbons contained in the exhaust gas, a catalytic converter for the catalytic aftertreatment of the exhaust gas, an electrically heatable catalytic converter and a cracking catalytic converter for cracking long-chain hydrocarbons into shorter-chain hydrocarbons are arranged in the exhaust gas line.

Claims

1.-8. (canceled)

9. A device for aftertreatment of exhaust gas of an internal combustion engine, comprising: an exhaust gas line, which is configured to feed the exhaust gas expelled from the internal combustion engine to at least one component for exhaust gas aftertreatment, wherein arranged in the exhaust gas line are: at least one adsorber configured to temporarily store of hydrocarbons contained in the exhaust gas; a catalytic converter for catalytic aftertreatment of the exhaust gas; an electrically heatable catalytic converter; and a cracking catalytic converter configured to crack long-chain hydrocarbons into shorter-chain hydrocarbons.

10. The device as claimed in claim 9, wherein reaction surfaces of the cracking catalytic converter are coated with activated aluminum silicates.

11. The device as claimed in claim 9, wherein the exhaust gas line further comprises a bypass channel that branches off from the exhaust gas line downstream of the electrically heatable catalytic converter and has the cracking catalytic converter, a cooling element, and an adsorber, and opens into the exhaust gas line upstream of the electrically heatable catalytic converter.

12. The device as claimed in claim 9, wherein the cracking catalytic converter is configured to crack long-chain hydrocarbons in the exhaust gas with in each case eight to twelve carbon atoms into hydrocarbons with a maximum of 7 carbon atoms.

13. The device as claimed in claim 9, wherein a desorption temperature of the at least one adsorber is in a temperature range of 150 degrees Celsius to 200 degrees Celsius.

14. The device as claimed in claim 9, wherein a light-off temperature at which cracking of the hydrocarbons in the cracking catalytic converter begins is 100 degrees Celsius.

15. The device as claimed in claim 9, wherein the exhaust gas line downstream of the cracking catalytic converter has a cooling element, by which the exhaust gas flowing out of the cracking catalytic converter is cooled.

16. The device as claimed in claim 9, wherein the cracking catalytic converter is a tubular reactor, wherein a coolant can flow through the tubular reactor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

[0026] FIG. 1 is a schematic illustration of an exhaust gas system from the internal combustion engine through different components for exhaust gas aftertreatment;

[0027] FIG. 2 is an alternative embodiment of an exhaust gas system; and

[0028] FIG. 3 is a further alternative embodiment of an exhaust gas system.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0029] FIG. 1 shows one possible embodiment of an exhaust system. Reference sign 1 indicates the internal combustion engine, from where the exhaust gas from the individual cylinders flows through the exhaust manifold in a tubular exhaust gas line. The first component for exhaust gas aftertreatment is a cracking catalytic converter 2, which is suitable for cracking long-chain hydrocarbons. An adsorber 3 for adsorbing hydrocarbons present in the exhaust gas is arranged downstream of the cracking catalytic converter 2 in the direction of flow. Following this in the exemplary embodiment of FIG. 1 are an electric heating catalytic converter 4 and a three-way catalytic converter 5, which can be arranged in any order. After flowing through the individual components for exhaust gas aftertreatment, the exhaust gas then flows through the exhaust into the environment.

[0030] FIG. 2 shows a different arrangement of the components for exhaust gas aftertreatment. Since the same components are used as in FIG. 1, identical components are provided with the same reference signs.

[0031] An electric heating catalytic converter 4 and/or a three-way catalytic converter 5 are/is arranged downstream of the internal combustion engine 1. Arranged downstream thereof are a cracking catalytic converter 2 and an adsorber 3. An electric heating catalytic converter 4 and/or a three-way catalytic converter 5 can in turn be arranged downstream of the adsorber 3.

[0032] FIG. 3 shows a further alternative arrangement, wherein the exhaust gas line has a main channel, in which an electrically heatable catalytic converter 4 and a three-way catalytic converter 5 are arranged. In addition, a bypass channel is shown, in which a cracking catalytic converter 2, a cooler 6 and an adsorber 3, for example an HC adsorber, are arranged. The bypass channel branches off downstream of the electrically heatable catalytic converter 4 and opens back into the main channel upstream of the electrically heatable catalytic converter 4. The adsorber 3 and the cracking catalytic converter 2 form an additional heat capacity. Since the carbon monoxides are to be reacted as early and completely as possible at the cracking catalytic converter 2, branching off into the bypass channel only takes place downstream of the electrically heatable catalytic converter 4.

[0033] The adsorber is used to store as much of the hydrocarbons as possible during the cold-start phase. For this purpose, the temperature in the adsorber should be kept low so that the adsorber does not desorb too quickly. Thus, the adsorber is deliberately positioned further back. After the cold-start phase, the adsorber, the cracking catalytic converter and the cooler are longer of any use since the exhaust gas temperature is already very high (they will only have an additional, unwanted heat capacity for CO and HC). In this case, only the main flow continues to be used.

[0034] The different features of the individual exemplary aspects can also be combined with one another.

[0035] The exemplary embodiments in FIGS. 1 to 3 have in particular no limiting character and serve to illustrate the concept of the invention.

[0036] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.