Exhaust system

Abstract

An exhaust gas system for purifying exhaust gases of an internal combustion engine, particularly a diesel engine in a motor vehicle, conducts the exhaust gas in a specific flow direction. A catalytic converter, particularly for converting hydrocarbons and carbon monoxides contained in the exhaust gas, an oxidation catalytic converter, particularly for converting nitrogen monoxide contained in the exhaust gas and a particulate trap for collecting particulates contained in the exhaust gas, are disposed successively in the flow direction. The exhaust gas system ensures a highly efficient conversion of harmful substances contained in the exhaust gas, and a particularly positive effect with respect to the regeneration of the particulate trap also occurs.

I claim:  
     
         1 . An exhaust system for purifying exhaust gas flowing from an internal combustion engine through the exhaust system in a flow direction, the exhaust system comprising, successively in the flow direction: 
 a catalytic converter, an oxidation catalytic converter, and a particulate trap for collecting particulates contained in the exhaust gas.    
     
     
         2 . The exhaust system according to  claim 1 , wherein the internal combustion engine is an automobile diesel engine.  
     
     
         3 . The exhaust system according to  claim 1 , wherein said catalytic converter converts carbon monoxides and hydrocarbons contained in the exhaust gas, and said oxidation catalytic converter converts nitrogen monoxide contained in the exhaust gas.  
     
     
         4 . The exhaust system according to  claim 1 , which further comprises a turbocharger, said catalytic converter disposed upstream of said turbocharger, and said oxidation catalytic converter disposed downstream of said turbocharger, in the flow direction.  
     
     
         5 . The exhaust system according to  claim 1 , wherein said catalytic converter is disposed close to the internal combustion engine.  
     
     
         6 . The exhaust system according to  claim 1 , wherein said catalytic converter is disposed in an exhaust manifold directly connected to the internal combustion engine.  
     
     
         7 . The exhaust system according to  claim 1 , wherein said oxidation catalytic converter has at least two zones including a zone disposed furthest away from the internal combustion engine and at least one remaining zone, and said zone disposed furthest away from the internal combustion engine has a higher specific heat capacity than said at least one remaining zone.  
     
     
         8 . The exhaust system according to  claim 1 , wherein said particulate trap is disposed directly downstream of said oxidation catalytic converter, in the flow direction.  
     
     
         9 . The exhaust system according to  claim 8 , wherein said particulate trap is disposed at a distance of less than 50 mm from said oxidation catalytic converter.  
     
     
         10 . The exhaust system according to  claim 8 , wherein said particulate trap is disposed at a distance of less than 20 mm from said oxidation catalytic converter.  
     
     
         11 . The exhaust system according to  claim 8 , wherein said oxidation catalytic converter and said particulate trap are disposed in a common housing.  
     
     
         12 . The exhaust system according to  claim 11 , wherein said oxidation catalytic converter is integrated in said particulate trap.  
     
     
         13 . The exhaust system according to  claim 12 , wherein said particulate trap has a catalytically active coating.  
     
     
         14 . The exhaust system according to  claim 1 , wherein the internal combustion engine has a volumetric capacity, and said particulate trap has a total volume of less than 75% of the volumetric capacity of the internal combustion engine.  
     
     
         15 . The exhaust system according to  claim 1 , wherein the internal combustion engine has a volumetric capacity, and said particulate trap has a total volume of less than 50% of the volumetric capacity of the internal combustion engine.  
     
     
         16 . The exhaust system according to  claim 1 , wherein the internal combustion engine has a volumetric capacity, and said particulate trap has a total volume of less than 25% of the volumetric capacity of the internal combustion engine.  
     
     
         17 . The exhaust system according to  claim 1 , wherein said particulate trap has freely accessible passages and turbulence points and calming points disposed in said passages.  
     
     
         18 . The exhaust system according to  claim 1 , wherein said particulate trap has freely accessible passages and diverter devices disposed in said passages.  
     
     
         19 . The exhaust system according to  claim 1 , wherein said oxidation catalytic converter has a catalytic converter volume, and said catalytic converter has a converter volume of at most half of said catalytic converter volume of said oxidation catalytic converter.  
     
     
         20 . The exhaust system according to  claim 1 , wherein at least one of said catalytic converter, oxidation catalytic converter and particulate trap has a honeycomb structure formed of at least partially structured metal foils defining passages through which exhaust gas can flow.