Device and method for regenerating a particulate filter arranged in the exhaust section of an internal combustion engine

Abstract

A device and a method for regenerating a particulate filter that is arranged in the exhaust tract of an internal combustion engine. There is disposed at least one NO oxidation catalytic converter upstream of the particulate filter for the oxidation of NO, and in particular to form NO 2 . At least one heating device is also provided upstream of the particulate filter, by way of which an exhaust-gas flow that is conducted towards the particulate filter can be heated to a defined temperature in accordance with defined regeneration parameters, in particular in accordance with a degree of loading of the particulate filter and/or in accordance with an efficiency of an NO 2 -based regeneration of the particulate filter by way of an NO 2 quantity formed in the at least one NO oxidation catalytic converter.

1 - 15 . (canceled) 
     
     
         16 . A configuration for regenerating a particle filter arranged in an exhaust tract of an internal combustion engine, comprising:
 at least one NO oxidation catalytic converter for oxidizing NO arranged upstream of the particle filter in an exhaust-gas flow direction;   at least one heating device arranged upstream of the particle filter and configured to heat an exhaust-gas flow being conducted to the particle filter to a defined temperature in dependence of one or more defined regeneration parameters.   
     
     
         17 . The configuration according to  claim 16 , wherein said NO oxidation catalytic converter is configured for oxidizing NO to form NO 2 . 
     
     
         18 . The configuration according to  claim 16 , wherein the one or more defined regeneration parameters are selected from the group consisting of a degree of loading of the particle filter and an efficiency of an NO 2 -based regeneration of the particle filter by way of an NO 2  quantity formed on said at least one NO oxidation catalytic converter. 
     
     
         19 . The configuration according to  claim 16 , wherein, at least during a regeneration phase characterized by a defined increase in the exhaust-gas temperature upstream of the particle filter, a mass ratio between carbon and nitrogen dioxide contained in the exhaust gas is at least 1:4. 
     
     
         20 . The configuration according to  claim 19 , wherein, during the regeneration phase, the mass ratio of carbon to nitrogen dioxide in the exhaust gas is at least 1:8. 
     
     
         21 . The configuration according to  claim 16 , wherein said at least one heating device is configured for heating the exhaust-gas flow conducted to the particle filter to a temperature lying below a regeneration temperature of a pure active particle filter regeneration by way of a metering of hydrocarbons into the exhaust-gas flow. 
     
     
         22 . The configuration according to  claim 21 , wherein said at least one heating device is configured for heating the exhaust-gas flow to a temperature of less than 600° C. 
     
     
         23 . The configuration according to  claim 21 , wherein said at least one heating device is configured for heating the exhaust-gas flow to a temperature of less than or equal to approximately 550° C. and within a temperature window of approximately 300° C. to 550° C. 
     
     
         24 . The configuration according to  claim 21 , wherein said at least one heating device is configured for heating the exhaust-gas flow to a temperature of less than or equal to approximately 450° C. and within a temperature window of approximately 350° C. to 450° C. 
     
     
         25 . The configuration according to  claim 16 , wherein said at least one heating device is connected in parallel, with regard to the exhaust-gas flow, with said NO oxidation catalytic converter, so as to subject each of said heating device and said NO oxidation catalytic converter to one exhaust gas or gas flow, with a first exhaust-gas flow flowing through said NO oxidation catalytic converter and a second exhaust-gas flow flowing through or over said heating device, and the first and second exhaust-gas flows are merged downstream of said NO oxidation catalytic converter and said heating device and upstream of the particle filter. 
     
     
         26 . The configuration according to  claim 16 , wherein said at least one heating device is connected in series, with regard to the exhaust-gas flow, downstream of said NO oxidation catalytic converter and upstream of the particle filter. 
     
     
         27 . The configuration according to  claim 16 , wherein said at least one heating device is a burner or an oxidation catalytic converter formed as a heating catalytic converter. 
     
     
         28 . The configuration according to  claim 16 , wherein said at least one heating device is an HC oxidation catalytic converter, and wherein a dosing device is disposed for metering hydrocarbons for an exothermic reaction into the exhaust-gas flow upstream of said heating catalytic converter at predefined times and in predefined quantities as a function of defined dosing parameters. 
     
     
         29 . The configuration according to  claim 28 , wherein said at least one heating device is an HC oxidation catalytic converter with NO oxidation activity and said dosing device is configured for periodically dosing in hydrocarbons for an exothermic reaction into the exhaust-gas flow upstream of said heating catalytic converter. 
     
     
         30 . The configuration according to  claim 16 , which comprises a fresh-air line and a shut-off element for selectively shutting off said fresh-air line, said fresh-air line enabling a charge-air-side fresh-air flow and/or a charge air flow branched off downstream of an opening point of an exhaust-gas recirculation line into a charge-air line or a fresh-air flow delivered by way of a blower or compressor to be supplied to an exhaust-gas flow upstream of said at least one heating device and/or upstream of said NO oxidation catalytic converter. 
     
     
         31 . A method for regenerating a particle filter arranged in an exhaust tract, which method comprises:
 conducting an exhaust-gas flow through at least one NO oxidation catalytic converter for the oxidation of NO upstream of the particle filter;   conducting an exhaust-gas flow through at least one heating device and to the particle filter, and heating the exhaust-gas flow to a defined temperature in dependence on defined regeneration parameters.   
     
     
         32 . The method according to  claim 31 , which comprises providing the configuration according to  claim 16  and carrying out the method with the configuration. 
     
     
         33 . The method according to  claim 31 , which comprises heating the exhaust gas for active and passive particle filter regeneration which are combined at least at times. 
     
     
         34 . The method according to  claim 31 , wherein the defined regeneration parameters are selected from a degree of loading of the particle filter and/or an efficiency of an NO 2 -based regeneration of the particle filter by means of an NO 2  quantity formed on the at least one NO oxidation catalytic converter. 
     
     
         35 . The method according to  claim 31 , wherein at least during a regeneration phase, which is characterized by a defined increase in an exhaust-gas temperature upstream of the particle filter, a mass ratio between carbon and nitrogen dioxide contained in the exhaust gas is at least 1:4. 
     
     
         36 . The method according to  claim 35 , wherein the mass ratio of carbon to nitrogen dioxide is 1:8, at least during the regeneration phase. 
     
     
         37 . The method according to  claim 31 , which comprises heating the exhaust-gas flow conducted to the particle filter with the at least one heating device to a temperature below a regeneration temperature of a pure active particle filter regeneration by way of metering hydrocarbons into the exhaust-gas flow. 
     
     
         38 . The method according to  claim 37 , which comprises heating the exhaust-gas flow to a temperature below 600° C. 
     
     
         39 . The method according to  claim 37 , which comprises heating the exhaust-gas flow to a temperature of less or equal to approximately 550° C., with a temperature window extending from approximately 300° C. to no more than 550° C. 
     
     
         40 . The method according to  claim 37 , which comprises heating the exhaust-gas flow to a temperature of less or equal to approximately 450° C., with a temperature window extending from approximately 350° C. to no more than 450° C. 
     
     
         41 . The method according to  claim 31 , which comprises providing an open-loop or closed-loop control device for predefining the temperature of the exhaust-gas flow conducted to the particle filter in a defined region of at least one exhaust-gas flow as a function of an NO 2  concentration and/or the loading of the particle filter and/or the regeneration capability of the particle filter. 
     
     
         42 . The method according to  claim 31 , which comprises providing the heating device in parallel, in terms of flow, with the NO oxidation catalytic converter and conducting a first exhaust-gas flow through the NO oxidation catalytic converter and a second exhaust-gas flow through or over the heating device, and merging the first and second exhaust-gas flows downstream of the NO oxidation catalytic converter and the heating device and upstream of the particle filter. 
     
     
         43 . The method according to  claim 31 , wherein the heating device is arranged downstream of the NO oxidation catalytic converter and upstream of the particle filter, and passing the exhaust-gas flow in a series flow therethrough. 
     
     
         44 . The method according to  claim 31 , which comprises supplying a predefined quantity of a charge-air-side fresh-air flow and/or a predefined quantity of a charge-air flow branched off downstream of the opening point of an exhaust-gas recirculation line into a charge-air line to the exhaust-gas flow upstream of the heating device at predefined times and/or when a predefined exhaust-gas temperature is exceeded and/or when a predefined lambda value is undershot and/or when a predefined oxygen value is undershot. 
     
     
         45 . The method according to  claim 31 , which comprises, during a regeneration of the particle filter, varying at least one of an NO x  untreated emissions of the internal combustion engine or an oxidation capability of the NO oxidation catalytic converter by adjusting defined operating parameters. 
     
     
         46 . The method according to  claim 45 , wherein the varying step comprises increasing at least one operating parameter selected from the group consisting of a fuel injection pressure, a start of injection, an exhaust-gas recirculation rate, and a number of injections.