Exhaust purification with on-board ammonia production

Abstract

A first aspect of the present disclosure includes a power source for use with selective catalytic reduction systems for exhaust-gas purification. The power source may comprise a first cylinder group with a first air-intake passage and a first exhaust passage, and a second cylinder group with a second air-intake passage and a second exhaust passage. The power source may further include a first forced-induction system in fluid communication with the first air-intake passage, and a second forced-induction system in fluid communication with the second air-intake passage. A catalyst may be disposed downstream of the fuel-supply device to convert at least a portion of the exhaust stream in the first exhaust passage into ammonia.

1 . A power source for use with selective catalytic reduction systems for exhaust-gas purification, comprising: 
 a first cylinder group with a first air-intake passage and a first exhaust passage;    a second cylinder group with a second air-intake passage and a second exhaust passage;    a first forced-induction system in fluid communication with the first air-intake passage;    a second forced-induction system in fluid communication with the second air-intake passage; and    a catalyst disposed downstream of the first cylinder group to convert at least a portion of the exhaust stream in the first exhaust passage into ammonia.    
   
   
       2 . The power source of  claim 1 , further including a valve for controlling the flow of air into the first air-intake passage.  
   
   
       3 . The power source of  claim 1 , further including a fuel-supply device configured to supply fuel into the first exhaust passage.  
   
   
       4 . The power source of  claim 3 , wherein an exhaust stream in the first exhaust passage is lean upstream from the fuel-supply device.  
   
   
       5 . The power source of  claim 4 , wherein the exhaust stream in the first exhaust passage is rich downstream from the fuel-supply device.  
   
   
       6 . The power source of  claim 1 , wherein the first forced-induction system and second forced-induction system include turbochargers.  
   
   
       7 . The power source of  claim 1 , wherein the second exhaust passage includes an oxidation catalyst.  
   
   
       8 . The power source of  claim 1 , wherein the first exhaust passage and the second exhaust passage are fluidly connected downstream from the fuel-supply device to form a merged exhaust passage.  
   
   
       9 . The power source of  claim 8 , further including a catalyst disposed in the merged exhaust passage and configured to facilitate a reaction between ammonia and NOx to at least partially remove NOx from the merged exhaust passage.  
   
   
       10 . A method of operating a power source for use with selective catalytic reduction systems for exhaust-gas purification, comprising: 
 supplying air through a first air-intake passage to a first cylinder group including one or more cylinders using a first turbocharger;    supplying fuel to the one or more cylinders of the first cylinder group;    supplying air through a second air-intake passage to a second cylinder group including at least two cylinders using a second turbocharger;    supplying fuel to the cylinders of the second cylinder group; and    controlling the flow of air and fuel to the cylinders of the first and second cylinder group to produce a substantially equal power output in each of the cylinders of both the first and second cylinder group.    
   
   
       11 . The method of  claim 10 , further including supplying a first exhaust stream from the first cylinder group to a first exhaust passage in fluid communication with the one or more cylinders of the first cylinder group, wherein the at least a portion of the first exhaust stream includes NOx.  
   
   
       12 . The method of  claim 11 , further including converting at least a portion of the first exhaust stream into ammonia.  
   
   
       13 . The method of  claim 12 , further including using the fuel-supply device to make the first exhaust stream rich downstream of the fuel-supply device.  
   
   
       14 . The method of  claim 12 , further including merging the exhaust stream of the first exhaust passage with the exhaust stream of the second exhaust passage to form a merged exhaust stream.  
   
   
       15 . The method of  claim 14 , further including exposing the merged exhaust stream to a catalyst configured to facilitate a reaction between ammonia and NOx; 
 and at least partially removing NOx from the merged exhaust stream.    
   
   
       16 . A machine for use with selective catalytic reduction systems for exhaust-gas purification, comprising: 
 a first cylinder group with a first air-intake passage and a first exhaust passage;    a second cylinder group with a second air-intake passage and a second exhaust passage;    a first forced-induction system in fluid communication with the first air-intake passage;    a second forced-induction system in fluid communication with the second air-intake passage;    an engine control unit configured to control the flow of air and fuel into each of the cylinders of the first and second cylinder groups to produce substantially equal power output from each of the cylinders of the first and second cylinder groups;    a catalyst disposed downstream of the first cylinder group to convert at least a portion of the exhaust stream in the first exhaust passage into ammonia;    a merged exhaust passage downstream of the catalyst and in fluid communication with the first exhaust passage and second exhaust passage; and    a NOx-reducing catalyst in fluid communication with the merged exhaust passage.    
   
   
       17 . The power source of  claim 16 , wherein the first and second cylinders are diesel cylinders.  
   
   
       18 . The power source of  claim 16 , wherein the first and second cylinders are natural gas cylinders.  
   
   
       19 . The power source of  claim 16  wherein the first and second cylinders are gasoline cylinders.  
   
   
       20 . The power source of  claim 16 , wherein the first forced-induction system and second forced-induction system include turbochargers.