Procedure and device to heat a reducing agent generation system

Abstract

The invention concerns a procedure to heat a reducing agent generation system of an exhaust gas aftertreatment system of an internal combustion engine by combustion of fuel, whereby the reducing agent is produced for the selective catalytic reduction of nitrogen oxides in the exhaust gas of the internal combustion engine in the intermittently operated reducing agent generation system, whereby the reducing agent generation system consists of a plasma burner, a mixing chamber located downstream or upstream from the plasma chamber, an oxidation reformation unit as well as a nitrogen oxide storage/ammonia production unit and whereby nitrogen oxide is produced in a plasma in the plasma burner. The invention concerns additionally a corresponding device. The task of the invention concerning the procedure is thereby solved, in that the combustion of the fuel is ignited by the plasma. For this reason, the heating of the catalytic components required at the start of the reducing agent generation system results through the combustion of fuel by means of a burner functionality, which consists of a fuel metering mechanism and the existing plasma burner. A special heating burner as an auxiliary mechanism can be omitted.

The invention claimed is: 
     
       1. A method of heating up a reducing agent generation system of an exhaust gas aftertreatment system of an internal combustion engine by combustion of fuel, the reducing agent generation system comprising a plasma burner, a mixing chamber located downstream or upstream from the a plasma chamber, an oxidation reformation unit, and a combined nitrogen oxide storage and ammonia production unit, the method comprising:
 producing the reducing agent for selective catalytic reduction of nitrogen oxides in an exhaust gas of the internal combustion engine in the intermittently operated reducing agent generation system; 
 producing nitrogen oxide in a plasma in the plasma burner, wherein the combustion of the fuel is ignited by the plasma; 
 producing nitrogen oxide in a nitrogen oxide production phase, in the plasma of the plasma burner; 
 metering fuel into the mixing chamber and in a subsequent ignition phase the fuel is ignited by the plasma, and in a subsequent heating phase the plasma is turned off; and 
 additionally metering fuel into the mixing chamber and combusting the fuel and in a subsequent hydrogen production phase, ending the fuel combustion and vaporizing the fuel in the mixing chamber. 
 
     
     
       2. A method according to  claim 1 , wherein the step of metering fuel into the mixing chamber includes delivering fuel is delivered to the mixing chamber upstream from the plasma chamber. 
     
     
       3. A method according to  claim 1 , wherein the step of metering fuel into the mixing chamber includes delivering fuel is delivered to the mixing chamber downstream from the plasma chamber and feeding the plasma is fed into the mixing chamber. 
     
     
       4. A method according to  claim 1 , wherein after beginning to meter in the fuel, the plasma is additionally operated for a selective time duration, preferably for a time duration between one and five seconds, after a beginning of the metering in of the fuel. 
     
     
       5. A method according to  claim 1 , wherein the fuel is vaporized before combustion on a hot surface area, which was heated during the nitrogen oxide production phase, of the mixing chamber located either downstream or upstream from the plasma chamber. 
     
     
       6. A method of heating up a reducing agent generation system of an exhaust gas aftertreatment system of an internal combustion engine by combustion of fuel, the reducing agent generation system comprising a plasma burner, a mixing chamber located downstream or upstream from the plasma chamber, an oxidation reformation unit, and a combined nitrogen oxide storage and ammonia production unit, the method comprising producing the reducing agent for selective catalytic reduction of nitrogen oxides in an exhaust gas of the internal combustion engine in the intermittently operated reducing agent generation system; and producing nitrogen oxide in a plasma in the plasma burner, wherein the combustion of the fuel is ignited by the plasma, wherein the fuel or the air delivered in a counter flow is warmed on an outside cladding of the plasma burner. 
     
     
       7. A device to heat a reducing agent generation system of an exhaust gas aftertreatment system of an internal combustion engine by combustion of fuel, which is metered in by way of a fuel metering mechanism, whereby the reducing agent generation system comprises a plasma burner, an oxidation reformation unit, and a combined nitrogen oxide storage/ammonia production unit for the intermittent production of ammonia from fuel and air or exhaust gas for selective catalytic reduction of nitrogen oxides in an exhaust gas of an internal combustion engine,
 wherein a plasma of the plasma burner ignites the fuel, 
 wherein the plasma burner is configured:
 to produce nitrogen oxide in a nitrogen oxide production phase, in the plasma of the plasma burner; 
 to meter fuel into the mixing chamber, and in a subsequent ignition phase, have the fuel is ignited by the plasma, and in a subsequent heating phase, have the plasma is turned off; and 
 
 additionally to meter fuel into the mixing chamber and combusting combust the fuel and in a subsequent hydrogen production phase, to end the fuel combustion and vaporizing the fuel in the mixing chamber. 
 
     
     
       8. A device according to  claim 7 , wherein a housing of the plasma burner has a tapered interior area in the area in the direction of gas flow succeeding the plasma chamber. 
     
     
       9. A device according to  claim 7 , further including a flame holder between the fuel metering mechanism and the ignition area. 
     
     
       10. A device according to  claim 7 , further including two fuel metering mechanisms or a joint fuel metering mechanism for the fuel delivery during heating and for the fuel delivery during a H 2 /CO production phase. 
     
     
       11. A device according to  claim 7 , wherein the plasma of the plasma burner is developed into one or more plasma jet zones. 
     
     
       12. A device according to  claim 11 , wherein the plasma jet zones are disposed tangentially around an ignition area or linearly along an ignition area.