Internal combustion engine comprising a reducing agent production unit and operating method therefor

Abstract

An internal combustion engine with a reducing agent-generating unit for generation of an H 2 -containing and/or NH 3 -containing reducing gas, which can be added to an exhaust gas line upstream from an NO x reducing catalytic converter, and a procedure for the operation of such an internal combustion engine are proposed. The reducing agent-generating unit has an NO x generation step and an H 2 generation step in serial arrangement. NH 3 is formed at least temporarily by chemical reaction by the reducing agent-generating unit from NO x produced in the NO x generation step. The invention is applicable in motor vehicles, especially in passenger vehicles with Diesel engines.

1 - 18 . (canceled)  
   
   
       19 . An internal combustion engine comprising: 
 an exhaust gas line in which an NO x  reduction catalytic converter is arranged, and    a reducing agent-generating unit for generation of H 2 -containing and NH 3 -containing reducing gas which can be added upstream of the NO x  reduction catalytic converter in the exhaust gas line,    wherein the reducing agent-generating unit can be supplied with at least one of an HC-containing fuel, air, and exhaust gas, and    wherein the reducing agent-generating unit has an NO x  generation step and an H 2  generation step in serial arrangement.    
   
   
       20 . The internal combustion engine according to  claim 19 , wherein the NO x  generation step is arranged downstream from the H 2  generation step.  
   
   
       21 . The internal combustion engine according to  claim 19 , wherein the NO x  generation step is arranged upstream from the H 2  generation step.  
   
   
       22 . The internal combustion engine according to  claim 19 , further comprising an NH 3  generation step arranged downstream from the NO X  generation step.  
   
   
       23 . The internal combustion engine according to  claim 20 , further comprising an NH 3  generation step arranged downstream from the NO X  generation step.  
   
   
       24 . The internal combustion engine according to  claim 21 , further comprising an NH 3  generation step arranged downstream from the NO X  generation step.  
   
   
       25 . The internal combustion engine according to  claim 19 , wherein the reducing agent-generating unit can be operated alternately in first and second operating modes in such a way that, during the first operating mode, an NO X -containing gas can be produced and, during the second operating mode, an H 2 -containing and NH 3 -containing reducing gas can be produced.  
   
   
       26 . The internal combustion engine according to  claim 22 , wherein a reducing agent-generating unit can be operated alternately in first and second operating modes in such a way that, in the first operating mode, an NO X -containing gas can be produced and, in the second operating mode, an H 2 -containing and NH 3 -containing reducing gas can be produced.  
   
   
       27 . The internal combustion engine according to  claim 23 , wherein a reducing agent-generating unit can be operated alternately in first and second operating modes in such a way that, in the first operating mode, an NO X -containing gas can be produced and, in the second operating mode, an H 2 -containing and NH 3 -containing reducing gas can be produced.  
   
   
       28 . The internal combustion engine according to  claim 24 , wherein a reducing agent-generating unit can be operated alternately in first and second operating modes in such a way that in the first operating mode of the NO X  generation step, an NO X -containing gas can be produced and, in the second operating mode, an H 2 -containing and NH 3 -containing reducing gas can be produced.  
   
   
       29 . The internal combustion engine according to  claim 25 , further comprising an NO X  intermediate storage unit arranged downstream from the NO X  generation step.  
   
   
       30 . The internal combustion engine according to  claim 26 , further comprising an NO X  intermediate storage unit arranged downstream from the NO X  generation step.  
   
   
       31 . The internal combustion engine according to  claim 27 , further comprising an NO X  intermediate storage unit arranged downstream from the NO X  generation step.  
   
   
       32 . The internal combustion engine according to  claim 28 , further comprising an NO X  intermediate storage unit arranged downstream from the NO X  generation step.  
   
   
       33 . The internal combustion engine according to  claim 29 , wherein the NO X  intermediate storage unit is designed for reaction of stored NO X  with H 2  to NH 3 .  
   
   
       34 . The internal combustion engine according to  claim 30 , wherein the NO X  intermediate storage unit is designed for reaction of stored NO X  with H 2  to NH 3 .  
   
   
       35 . The internal combustion engine according to  claim 31 , wherein the NO X  intermediate storage unit is designed for reaction of stored NO X  with H 2  to NH 3 .  
   
   
       36 . The internal combustion engine according to  claim 32 , wherein the NO X  intermediate storage unit is designed for reaction of stored NO X  with H 2  to NH 3 .  
   
   
       37 . The internal combustion engine according to  claim 21 , wherein the H 2  generation step is designed for reaction of supplied NO X  into NH 3 .  
   
   
       38 . The internal combustion engine according to  claim 24 , wherein the H 2  generation step is designed for reaction of supplied NO X  into NH 3 .  
   
   
       39 . The internal combustion engine according to  claim 28 , wherein the H 2  generation step is designed for reaction of supplied NO X  into NH 3 .  
   
   
       40 . The internal combustion engine according  claim 32 , wherein the H 2  generation step is designed for reaction of supplied NO X  into NH 3 .  
   
   
       41 . The internal combustion engine according  claim 36 , wherein the H 2  generation step is designed for reaction of supplied NO X  into NH 3 .  
   
   
       42 . The internal combustion engine according to  claim 19 , wherein the engine is a Diesel engine.  
   
   
       43 . A process for operation of an internal combustion engine having a reducing agent-generating unit and an exhaust gas line in which an NO X  reduction catalytic converter is arranged, whereby a reducing gas produced by the reducing agent-generating unit is added upstream of the NO X  reducing catalytic converter to the exhaust gas, wherein generation of the reducing gas comprises: 
 generating an NO X -containing gas from an NO X  generation stage allocated to the reducing agent-generating unit from at least one of air and exhaust gas supplied to the NO X  generation stage; and    intermediately storing NO X  when conducting the NO X -containing gas produced through an NO X  intermediate storage unit which is arranged downstream from the NO X  generation stage and allocated to the reducing agent-generating unit; or    generating an H 2 -containing gas by an H 2  generation stage allocated to the reducing agent-generating unit and arranged upstream from an NO X  intermediate storage unit from fuel and air or exhaust gas supplied to the H 2  generation stage; and    reacting NO X  stored in the NO X  intermediate storage unit with the gas produced into NH 3  so that a reducing gas containing H 2  and NH 3  is produced.    
   
   
       44 . The process according to  claim 43 , wherein reaction of NO x  into NH 3  takes place in the catalytic NH 3  generation stage, which is allocated to the reducing agent generation unit and arranged downstream from the NO X  intermediate storage unit.  
   
   
       45 . The process according to  claim 43 , wherein intermediate storage of NO X  and reaction of NO X  into NH 3  is performed with a catalytic NO X  intermediate storage unit.  
   
   
       46 . The process according to  claim 43 , wherein the NO X  reducing catalytic converter is divided into a denox catalytic converter stage for reaction of NO X  with H 2  and an SCR catalytic converter stage for reaction of NO X  with NH 3 , and wherein the reducing gas is supplied to the exhaust gas as a function of its composition at an input side to the SCR catalytic converter stage or on an input side to the denox catalytic converter stage.  
   
   
       47 . The process according to  claim 44 , wherein the NO X  reducing catalytic converter is divided into a denox catalytic converter stage for reaction of NO X  with H 2  and an SCR catalytic converter stage for reaction of NO X  with NH 3 , and wherein the reducing gas is supplied to the exhaust gas as a function of its composition at an input side to the SCR catalytic converter stage or on an input side to the denox catalytic converter stage.  
   
   
       48 . The process according to  claim 45 , wherein the NO X  reducing catalytic converter is divided into a denox catalytic converter stage for reaction of NO X  with H 2  and an SCR catalytic converter stage for reaction of NO X  with NH 3 , and wherein the reducing gas is supplied to the exhaust gas as a function of its composition at an input side to the SCR catalytic converter stage or on an input side to the denox catalytic converter stage.  
   
   
       49 . A process for operation of an internal combustion engine having a reducing agent-generating unit and an exhaust gas line in which an NO X  reduction catalytic converter is arranged, whereby a reducing gas produced by the reducing agent-generating unit is added upstream from the NO X  reducing catalytic converter to the exhaust gas, wherein generation of the reducing gas comprises: 
 generating an NO X -containing gas from an NO X  generation stage allocated to the reducing agent-generating unit from at least one of air and exhaust gas supplied to the NO X  generation stage; and    generating an H 2 -containing gas and an NH 3 -containing reducing gas from an H 2  generation stage allocated to the reducing agent-generating unit and arranged downstream from the NO X  generation stage based on fuel fed to the H 2  generation stage, NO X -containing gas produced, fuel supplied, and at least one of air and exhaust gas.    
   
   
       50 . The process according to  claim 49 , wherein the NO X  reducing catalytic converter is divided into a denox catalytic converter stage for reaction of NO X  with H 2  and an SCR catalytic converter stage for reaction of NO X  with NH 3 , and wherein the reducing gas is supplied to the exhaust gas as a function of its composition at an input side to the SCR catalytic converter stage or on an input side to the denox catalytic converter stage.