Method of exhaust gas aftertreatment

Abstract

A method of exhaust gas aftertreatment of an exhaust gas of an internal combustion engine includes pre-treating the exhaust gas pre-treated by using a thermoreactor to catalytically oxidize the exhaust gas. Preferably, the exhaust gas is catalytically oxidized in the thermoreactor.

Claims

1. An exhaust gas aftertreatment apparatus for an internal combustion engine, said exhaust gas aftertreatment apparatus comprising: an intake for exhaust gas; a thermoreactor including a thermal reaction zone, a first storage mass, and a second storage mass, said thermoreactor being configured to perform a partial oxidation of methane to form carbon monoxide; a catalytic reaction zone connected downstream of said thermoreactor in a flow direction of the exhaust gas through said exhaust gas aftertreatment apparatus, said catalytic reaction zone being configured to break down by catalytic oxidation the carbon monoxide formed by said thermoreactor; and a switching-over mechanism configured to switch a direction of flow of the exhaust gas through said exhaust gas aftertreatment apparatus between a first direction through the first storage mass, the thermal reaction zone, and then the second storage mass, and a second direction through the second storage mass, the thermal reaction zone, and then the first storage mass.

2. The exhaust gas aftertreatment apparatus as set forth in claim 1, wherein said thermal reaction zone of said thermoreactor and said catalytic reaction zone are arranged in a common housing.

3. The exhaust gas aftertreatment apparatus as set forth in claim 1, wherein said catalytic reaction zone is connected downstream of said thermal reaction zone in a housing separate from said thermal reaction zone in the flow direction of the exhaust gas through said exhaust gas aftertreatment apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in greater detail hereinafter with reference to the drawings, in which:

(2) FIG. 1 is a diagrammatic view of an internal combustion engine having an exhaust gas aftertreatment apparatus,

(3) FIG. 2 is a diagrammatic view of an internal combustion engine having an exhaust gas aftertreatment apparatus in an alternative configuration, and

(4) FIG. 3 is a diagrammatic view of an internal combustion engine with exhaust gas aftertreatment according to the state of the art.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) The detailed specific description now follows. FIG. 1 shows a diagrammatic view illustrating an internal combustion engine 1 connected by way of the exhaust gas manifold 2 to the exhaust gas aftertreatment apparatus 3. The flow direction of the exhaust gas through the thermoreactor 11 can be altered by the switching-over mechanism 4. Thus, in operation, the direction of flow of the exhaust gas can alternatingly first be through the first storage mass 5, the thermal reaction zone 7, and the second storage mass 6. Upon a reversal in the flow direction, the exhaust gas firstly flows through the second storage mass 6, then through the thermal reaction zone 7, and finally through the first storage mass 5. After flowing through the exhaust gas aftertreatment apparatus 3, the exhaust gas leaves the arrangement by way of the conduit 8 and is fed to a chimney or a waste heat recovery arrangement (both of these are not shown). In the embodiment of FIG. 1, the volume portions 9 of the storage masses 5 and 6, that are towards the reaction chamber 7, are provided with a catalytic coating or a catalytically active material. In operation of the exhaust gas aftertreatment apparatus 3, therefore, the volume portions (catalytic reaction zones) 9 take over the task of catalytic oxidation of the exhaust gas which has been pre-treated in the thermal reaction zone 7 of the thermoreactor.

(6) For the sake of completeness, the open loop/closed loop control device 12 is shown, which on the one hand can receive signals from the internal combustion engine 1 and the exhaust gas aftertreatment apparatus 3, and which on the other hand can also send commands to actuating members of the exhaust gas aftertreatment apparatus 3. Also shown is the fuel line 13, by way of which the internal combustion engine 1 is supplied with fuel, for example gas fuel. A branching can be provided on the fuel line 13, by way of which support gas can be fed to the thermoreactor 11 for additional heating.

(7) FIG. 2 shows a diagrammatic view of an internal combustion engine 1 with an exhaust gas aftertreatment apparatus 3 similar to FIG. 1, but in this case the exhaust gas aftertreatment apparatus 3 is formed from a thermoreactor 11 comprising storage masses 5 and 6, a thermal reaction zone 7, and an oxidation catalyst 10 provided downstream of the thermoreactor in the conduit 8. The flow direction through the thermoreactor 11 can again be alternatingly changed by way of the switching-over mechanism 4. In this embodiment, the thermoreactor 11 does not have any catalytically coated volume portions. The exhaust gas pre-treated in the thermoreactor 11 flows through the oxidation catalyst 10 and from there is passed to a chimney or an exhaust gas heat utilization arrangement (both not shown).

(8) FIG. 3 is a diagrammatic view showing an internal combustion engine 1 with an exhaust gas aftertreatment apparatus according to the state of the art. Here there is a thermoreactor without catalytically coated zones.

LIST OF REFERENCES USED

(9) 1 internal combustion engine 2 exhaust gas manifold 3 exhaust gas aftertreatment apparatus 4 switching-over mechanism 5, 6 thermal storage masses 7 thermal reaction zone 8 exhaust gas conduit 9 catalytically coated/catalytically active zone or zones 10 oxidation catalyst 11 thermoreactor 12 open loop/closed loop control device 13 fuel line guide system