Method for flushing an exhaust-gas cleaning system

Abstract

A method for flushing an exhaust-gas cleaning system of an internal combustion engine having a catalytic converter with at least one catalyst bed, whereby an exhaust gas from the internal combustion engine is supplied to the exhaust-gas cleaning system in an active operating phase of the exhaust-gas cleaning system, and no exhaust gas is supplied to the exhaust-gas cleaning system in a passive operating phase of the exhaust-gas cleaning system, whereby a temperature of the at least one catalyst bed is determined and the flushing is performed depending on the determined temperature, whereby the exhaust-gas cleaning system is flushed in the passive operating phase of the exhaust-gas cleaning system by a flushing device, which is connected directly to an exhaust-gas line.

What is claimed is: 
     
         1 . A method for flushing an exhaust-gas cleaning system of an internal combustion engine comprising a catalytic converter with at least one catalyst bed, wherein an exhaust gas from the internal combustion engine is supplied to the exhaust-gas cleaning system in an active operating phase of the exhaust-gas cleaning system, and no exhaust gas is supplied to the exhaust-gas cleaning system in a passive operating phase of the exhaust-gas cleaning system, wherein a temperature of the at least one catalyst bed is determined and the flushing is performed depending on the determined temperature, wherein the exhaust-gas cleaning system is flushed in the passive operating phase of the exhaust-gas cleaning system by a flushing device, which is connected directly to an exhaust-gas line. 
     
     
         2 . The method according to  claim 1 , wherein the exhaust-gas cleaning system is flushed only in the passive operating phase of the exhaust-gas cleaning system. 
     
     
         3 . The method according to  claim 1 , wherein the temperature of the at least one catalyst bed is determined in the passive operating phase of the exhaust-gas cleaning system. 
     
     
         4 . The method according to  claim 1 , wherein the exhaust-gas cleaning system is flushed after a shutdown of the internal combustion engine. 
     
     
         5 . The method according to  claim 1 , wherein a period of time during which the exhaust-gas cleaning system is flushed is determined depending on the determined temperature. 
     
     
         6 . The method according to  claim 1 , wherein the exhaust-gas cleaning system is flushed before a start-up of the internal combustion engine. 
     
     
         7 . The method according to  claim 1 , wherein the exhaust-gas cleaning system is flushed until the temperature of the at least one catalyst bed is lower than or equal to a predetermined setpoint temperature. 
     
     
         8 . The method according to  claim 7 , wherein the exhaust-gas cleaning system is flushed if the temperature of the at least one catalyst bed before flushing is higher than or equal to a predetermined threshold value E. 
     
     
         9 . The method according to  claim 1 , wherein a first exhaust-gas temperature value is determined upstream of the catalytic converter and a second exhaust-gas temperature value is determined downstream of the catalytic converter, wherein the temperature of the at least one catalyst bed is determined by taking account of the first exhaust-gas temperature value and the second exhaust-gas temperature value.