Oxygen-enriched feedgas for reformer in emissions control system

Abstract

A method and systems for supplying oxygen-enriched feedgas to a reformer. The reformer is placed on an exhaust bypass line, which has a valve upstream the reformer, for opening and closing the flow of exhaust gas into the bypass line. The bypass line receives atmospheric air at a venturi, and this air is mixed with the exhaust gas to supply feedgas to the reformer. The output of the reformer is directed via the bypass line to a point on a main exhaust line upstream an emissions control device, such as a NAC.

1 . A method, for use in a diesel engine having an air-charging device, of providing a reformate to an emissions control device on an exhaust line, comprising: 
 using a bypass line to carry exhaust gas from the engine to a point on the exhaust line upstream the emissions control device;    opening a valve on the bypass line upstream the reformer;    directing atmospheric air to a venturi in the bypass line, upstream the reformer;    receiving the air and exhaust into the reformer;    using the reformer to generate the reductant; and    routing the reductant, via the bypass line, to the point on the exhaust line upstream the emissions control device.    
   
   
       2 . The method of  claim 1 , further comprising the step of closing the exhaust flow from the air-charging device.  
   
   
       3 . The method of  claim 1 , further comprising the step of using a valve to decrease or stop the flow of exhaust through the exhaust line.  
   
   
       4 . The method of  claim 1 , further comprising the step of using backpressure of the air-charging device to boost flow to the reformer.  
   
   
       5 . The method of  claim 1 , wherein the emissions control device is a NOx adsorption catalyst (NAC), and wherein the method operates during regeneration of the NAC.  
   
   
       6 . The method of  claim 1 , further providing the step of using a sensor to detect the oxygen provided to the reformer.  
   
   
       7 . The method of  claim 1 , wherein the method is used with closed loop control hardware for control of oxygen to the reformer.  
   
   
       8 . The method of  claim 1 , wherein the bypass line begins at a point between the exhaust manifold and the air-charging device.  
   
   
       9 . The method of  claim 1 , wherein the atmospheric air is routed from the air output side of the air-charging device.  
   
   
       10 . The method of  claim 1 , wherein the atmospheric air is routed directed directly from atmosphere.  
   
   
       11 . An exhaust system for a diesel engine having an air-charging device, comprising: 
 an exhaust line for carrying exhaust gas from the engine to atmosphere;    at least one emissions control device on the exhaust line;    a bypass line to carry exhaust gas from the engine to a point on the exhaust line upstream the emissions control device;    a reformer on the bypass line;    a valve on the bypass line upstream the reformer, for opening and closing the flow of exhaust gas from the engine into the bypass line;    a venturi in the bypass line, upstream the reformer; and    an air inlet for receiving air into the bypass line at the venturi;    wherein the air inlet receives air from the air-charging device.    
   
   
       12 . The system of  claim 11 , further comprising a valve for closing the flow of exhaust into the exhaust line.  
   
   
       13 . A method, for use in a diesel engine, of providing a reformate to an emissions control device on an exhaust line, comprising: 
 using a bypass line to carry exhaust gas from the exhaust manifold of the engine to a point on the exhaust line upstream the emissions control device;    opening a valve on the bypass line upstream the reformer;    directing atmospheric air to a venturi in the bypass line, upstream the reformer;    receiving the air and exhaust into the reformer;    using the reformer to generate the reformate; and    routing the reformate, via the bypass line, to the point on the exhaust line upstream the emissions control device.    
   
   
       14 . The method of  claim 13 , further comprising the step of using a valve to decrease or stop the flow of exhaust through the exhaust line.  
   
   
       15 . The method of  claim 13 , wherein the emissions control device is a NOx adsorption catalyst (NAC), and wherein the method operates during regeneration of the NAC.  
   
   
       16 . The method of  claim 13 , further providing the step of using a sensor to detect the oxygen provided to the reformer.  
   
   
       17 . The method of  claim 13 , wherein the method is used with closed loop control hardware for control of oxygen to the reformer.  
   
   
       18 . An exhaust system for a diesel engine, comprising: 
 an exhaust line for carrying exhaust gas from the engine to atmosphere;    at least one emissions control device on the exhaust line;    a bypass line to carry exhaust gas from the engine to a point on the exhaust line upstream the emissions control device;    a reformer on the bypass line;    a valve on the bypass line upstream the reformer for opening and closing the flow of exhaust gas from the engine into the bypass line;    a venturi in the bypass line, upstream the reformer; and    an air inlet for receiving air into the bypass line at the venturi.    
   
   
       19 . The system of  claim 18 , wherein the emissions control device is a NOx adsorber catalyst (NAC).  
   
   
       20 . The system of  claim 18 , further comprising a valve for closing the flow of exhaust into the exhaust line.