Method and device for regenerating a particle filter

Abstract

A method for the targeted initiation of a regeneration of a particle filter in an exhaust-gas duct of an internal combustion engine which has a catalytic converter downstream of the particle filter in the flow direction of the exhaust gas, the regeneration of the particle filter taking place by means of an oxidative burn-off of the particles during the regeneration phase.

1 . A method for a targeted initiation of a regeneration of a particle filter ( 15 ) in an exhaust-gas duct ( 12 ) of an internal combustion engine ( 10 ) which has a catalytic converter ( 17 ,  18 ) downstream of the particle filter ( 15 ), the regeneration of the particle filter ( 15 ) taking place by means of an oxidative burn-off of the particles during the regeneration phase, characterized in that, when the internal combustion engine ( 10 ) is in a warm operating state but the temperature is still insufficient for a regeneration of the particle filter ( 15 ), measures are temporarily taken to increase the exhaust-gas temperature upstream of and/or in the particle filter ( 15 ). 
     
     
         2 . The method according to  claim 1 , characterized in that, for the targeted initiation of the regeneration of the particle filter ( 15 ), an ignition angle is shifted in a direction of a late ignition time. 
     
     
         3 . The method according to  claim 2 , characterized in that, during the shift of the ignition angle, a throttling action of the internal combustion engine is reduced. 
     
     
         4 . The method according to  claim 2 , characterized in that a homogeneous-split operating mode is used in addition to the late adjustment of the ignition angle. 
     
     
         5 . The method according to  claim 1 , characterized in that, from a lambda regulating mode around a lambda value of 1, regulation to a lambda value of >1 is carried out for a limited time and an oxygen accumulator of the catalytic converter ( 17 ,  18 ) is thereby filled, and subsequently, after the filling of the oxygen accumulator, a lambda value of <1 is set by a pilot control. 
     
     
         6 . The method according to  claim 5 , characterized in that the change in the lambda regulating mode is carried out by a combined particle filter/catalytic converter having a catalytic coating. 
     
     
         7 . The method according to  claim 1 , characterized in that a temperature in the particle filter ( 15 ) is used as a regulating variable for the initiation of the regeneration and for monitoring of the regeneration, said temperature being determined directly by means of at least one temperature sensor ( 14 ) arranged in or on the particle filter ( 15 ). 
     
     
         8 . The method according to  claim 1 , characterized in that a temperature in the particle filter ( 15 ) is used as a regulating variable for the initiation of the regeneration and for monitoring of the regeneration, said temperature being derived from signals of lambda probes ( 13 ,  16 ) which are arranged in the exhaust duct ( 12 ) upstream and downstream of the particle filter ( 15 ) and the catalytic converter ( 17 ,  18 ) and which serve for lambda regulation. 
     
     
         9 . The method according to  claim 1 , characterized in that a temperature in the particle filter ( 15 ) is used as a regulating variable for the initiation of the regeneration and for monitoring of the regeneration, said temperature being derived from signals of lambda probes ( 13 ,  16 ) which are arranged in the exhaust duct ( 12 ) upstream of the particle filter ( 15 ) and the catalytic converter ( 17 ,  18 ) and which serve for lambda regulation. 
     
     
         10 . The method according to  claim 1 , characterized in that a temperature in the particle filter ( 15 ) is used as a regulating variable for the initiation of the regeneration and for monitoring of the regeneration, said temperature being derived from signals of lambda probes ( 13 ,  16 ) which are arranged in the exhaust duct ( 12 ) downstream of the particle filter ( 15 ) and the catalytic converter ( 17 ,  18 ) and which serve for lambda regulation. 
     
     
         11 . The method according to  claim 1 , characterized in that a temperature in the particle filter ( 15 ) is used as a regulating variable for the initiation of the regeneration and for monitoring of the regeneration, said temperature being determined on a modeled basis from an exhaust-gas temperature model. 
     
     
         12 . The use of the method according to  claim 1  for regenerating a particle filter ( 15 ) in the exhaust duct ( 12 ) of an internal combustion engine ( 10 ) designed as a spark-ignition engine. 
     
     
         13 . A device for the targeted initiation and monitoring and regulation of the regeneration of a particle filter ( 15 ) in an exhaust duct ( 12 ) of an internal combustion engine ( 10 ) which has a catalytic converter ( 17 ,  18 ) downstream of the particle filter ( 15 ), the regeneration of the particle filter ( 15 ) taking place by means of an oxidative burn-off of the particles during the regeneration phase, and the initiation, control and monitoring of the regeneration of the particle filter ( 15 ) taking place by means of a control unit ( 21 ), characterized in that, by means of a program routine implemented in the control unit ( 21 ), measures are temporarily taken to targetedly increase the exhaust-gas temperature. 
     
     
         14 . The device according to  claim 13 , characterized in that the exhaust-gas temperature is increased upstream of and in the particle filter ( 15 ). 
     
     
         15 . The device according to  claim 13 , characterized in that the exhaust-gas temperature is increased upstream of the particle filter ( 15 ). 
     
     
         16 . The device according to  claim 13 , characterized in that the exhaust-gas temperature is increased in the particle filter ( 15 ). 
     
     
         17 . The device according to  claim 13 , characterized in that the control unit ( 21 ) evalutates signals of a first lambda probe ( 13 ) arranged upstream of the particle filter ( 15 ). 
     
     
         18 . The device according to  claim 13 , characterized in that the control unit ( 21 ) evalutates signals of a second lambda probe ( 16 ) arranged downstream of the particle filter ( 15 ) and/or downstream of the catalytic converter ( 17 ,  18 ). 
     
     
         19 . The device according to  claim 13 , characterized in that the control unit ( 21 ) evalutates signals of a at least one temperature sensor ( 14 ). 
     
     
         20 . The device according to  claim 13 , characterized in that an exhaust-gas temperature model is implemented within the control unit ( 21 ) and a regulating variable for the regeneration of the particle filter ( 15 ) is a modeled temperature of the particle filter ( 15 ) derived from said exhaust-gas temperature model.