Method and device for the catalytic conversion of gaseous pollutants in the exhaust gas of combustion engines

Abstract

The present invention is directed to a method and a device for the catalytic conversion of harmful substances contained in the exhaust gas of combustion engines, wherein the exhaust gas is forced to pass through a catalyst-carrying porous support. The support may be comprised of a catalytic material support itself, have a catalytic material coating its pores and/or have a catalytic layer on one or both of the surfaces through which the exhaust gas will travel.

1 . A method for the catalytic conversion of pollutants contained in an exhaust gas of an internal combustion engine, said method comprising contacting an exhaust gas with a catalyst, wherein the catalyst comprises a catalyst-carrying porous support with an open pore structure, wherein said support has a first surface and a second surface, and wherein the exhaust gas enters the support through said first surface, passes through the support, and leaves the catalyst through the said second surface.  
     
     
         2 . The method according to  claim 1 , wherein at least one catalytic layer is present on said first surface and/or said second surface.  
     
     
         3 . The method according to  claim 2 , wherein the support comprises a wall-flow-filter manufactured from an inert ceramic material.  
     
     
         4 . The method according to  claim 1 , wherein the support comprises a wall-flow filter manufactured by extrusion of a catalytic material.  
     
     
         5 . The method according to  claim 3 , wherein the internal combustion engine is a diesel engine or a lean bum direct injection engine and the catalyst is a NO x -storage catalyst, an SCR catalyst or a HC-DeNO x  catalyst for the reduction of nitrogen oxides.  
     
     
         6 . The method according to  claim 4 , wherein the internal combustion engine is a diesel engine or a lean burn direct injection engine and the catalyst is a NO x -storage catalyst, an SCR catalyst or a HC-DeNO x  catalyst for the reduction of nitrogen oxides.  
     
     
         7 . The method according to  claim 3 , wherein the internal combustion engine is a diesel engine and the catalyst is a diesel oxidation catalyst for the oxidation of carbon monoxide and hydrocarbons, as well as soluble organic compounds adhered to soot particles.  
     
     
         8 . The method according to  claim 4 , wherein the internal combustion engine is a diesel engine and the catalyst is a diesel oxidation catalyst for the oxidation of carbon monoxide and hydrocarbons, as well as soluble organic compounds adhered to soot particles.  
     
     
         9 . The method according to  claim 3 , wherein the internal combustion engine is a stoichiometrically operated gasoline engine and the catalyst is a three-way catalyst for simultaneous conversion of nitrogen oxides, hydrocarbons and carbon monoxide.  
     
     
         10 . The method according to  claim 4 , wherein the internal combustion engine is a stoichiometrically operated gasoline engine and the catalyst is a three-way catalyst for simultaneous conversion of nitrogen oxides, hydrocarbons and carbon monoxide.  
     
     
         11 . A device for the catalytic conversion of harmful substances in an exhaust gas of an internal combustion engine, wherein the device comprises a catalyst-carrying porous support with an open pore structure, and wherein said open pore structure has a first surface that permits the entry of the exhaust gas and a second surface that permits the exit of the exhaust gas.  
     
     
         12 . The device according to  claim 11 , wherein said catalyst-carrying porous support comprising a catalytic material.  
     
     
         13 . The device according to  claim 12 , wherein the catalytic material is a HC-absorber, a NO x -storage catalyst, a diesel oxidation catalyst, an SCR catalyst, a HC-DeNO x  catalyst or a three-way catalyst.  
     
     
         14 . The device according to  claim 13 , wherein the porous support is in the form of a wall-flow filter.  
     
     
         15 . The device according to  claim 11 , wherein a catalyst layer is attached to said first surface and/or said second surface.  
     
     
         16 . The device of  claim 11 , wherein said support comprises an inert ceramic material.  
     
     
         17 . An exhaust system comprising the device of  claim 11 , wherein the device is located within an exhaust gas pipe and said first surface is oriented upstream of said second surface.  
     
     
         18 . The exhaust system of  claim 17 , wherein said device spans a cross-section of said exhaust gas pipe.