Exhaust purification with on-board ammonia production

Abstract

A power source is provided for use with selective catalytic reduction systems for exhaust-gas purification. The power source has a first cylinder group fluidly connected to a first air-intake passage and a first exhaust passage, wherein the first air-intake passage is configured to provide air at a first set of characteristics. The power source also has a second cylinder group fluidly connected to a second air-intake passage and a second exhaust passage, wherein the second air-intake passage is configured to provide air at a second set of characteristics different from the first set of characteristics. An ammonia-producing catalyst may be disposed within the first exhaust passage and configured to convert at least a portion of a fluid in the first exhaust passage into ammonia. Further, a merged exhaust passage may be configured to connect the first exhaust passage and the second exhaust passage downstream of the ammonia-producing catalyst to facilitate a reaction between ammonia and NOx to at least partially remove NOx from the merged exhaust passage.

1 . A power source for use with selective catalytic reduction systems for exhaust-gas purification, comprising: 
 a first cylinder group fluidly connected to a first air-intake passage and a first exhaust passage, wherein the first air-intake passage is configured to provide air at a first set of characteristics;    a second cylinder group fluidly connected to a second air-intake passage and a second exhaust passage, wherein the second air-intake passage is configured to provide air at a second set of characteristics different from the first set of characteristics;    an ammonia-producing catalyst disposed within the first exhaust passage and configured to convert at least a portion of a fluid in the first exhaust passage into ammonia; and    a merged exhaust passage configured to connect the first exhaust passage and the second exhaust passage downstream of the ammonia-producing catalyst to facilitate a reaction between ammonia and NOx to at least partially remove NOx from the merged exhaust passage.    
   
   
       2 . The power source of  claim 1 , wherein the first air-intake passage includes a valve.  
   
   
       3 . The power source of  claim 2 , wherein the valve includes at least one of a throttle and a venturi assembly.  
   
   
       4 . The power source of  claim 2 , wherein the valve is configured to modify at least one characteristic of the first set of characteristics to be different from a corresponding characteristic of the second set of characteristics.  
   
   
       5 . The power source of  claim 2 , wherein the valve is configured to modify at least one characteristic of the first set of characteristics to permit the power source to produce substantially similar power output from a cylinder of the first cylinder group and a cylinder of the second cylinder group.  
   
   
       6 . The power source of  claim 1 , wherein the power source further includes a turbo-compound operably associated with at least one of the first exhaust passage, the second exhaust passage and the merged exhaust passage.  
   
   
       7 . The power source of  claim 1 , wherein the power source further includes a forced-induction system operably associated with at least one of the first air-intake passage, the second air-intake passage, the first exhaust passage, the second exhaust passage, and the merged exhaust passage.  
   
   
       8 . The power source of  claim 7 , wherein the forced-induction system includes a component of at least one of a turbocharger and a supercharger.  
   
   
       9 . A method of operating a power source for use with selective catalytic reduction systems for exhaust-gas purification, comprising: 
 supplying air at a first set of characteristics to a first air-intake passage fluidly connected to a first cylinder group, wherein the first air-intake passage includes a valve;    supplying air at a second set of characteristics to a second air-intake passage fluidly connected to a second cylinder group;    supplying a first exhaust stream from the first cylinder group to a first exhaust passage fluidly connected to the first cylinder group;    supplying a second exhaust stream from the second cylinder group to a second exhaust passage fluidly connected the second cylinder group;    converting at least a portion of the first exhaust stream to ammonia; and    merging the exhaust stream of the first exhaust passage with the exhaust stream of the second exhaust passage to form a merged exhaust stream in a merged exhaust passage fluidly connected to the first exhaust passage and the second exhaust passage.    
   
   
       10 . The method of  claim 9 , wherein the valve includes at least one of a throttle and a venturi assembly.  
   
   
       11 . The method of  claim 9 , wherein the valve is configured to modify at least one characteristic of the first set of characteristics to be different from a corresponding characteristic of the second set of characteristics.  
   
   
       12 . The method of  claim 9 , wherein the valve is configured to modify at least one characteristic of the first set of characteristics to permit the power source to produce substantially similar power output from a cylinder of the first cylinder group and a cylinder of the second cylinder group.  
   
   
       13 . The method of  claim 9 , wherein the method further includes using a turbo-compound operably associated with at least one of the first exhaust passage, the second exhaust passage and the merged exhaust passage.  
   
   
       14 . The method of  claim 9 , wherein the method further includes using a forced-induction system operably associated with at least one of the first air-intake passage, the second air-intake passage, the first exhaust passage, the second exhaust passage, and the merged exhaust passage.  
   
   
       15 . The method of  claim 14 , wherein the forced-induction system includes a component of at least one of a turbocharger and a supercharger.  
   
   
       16 . A machine, comprising: 
 a power source including: 
 a first cylinder group fluidly connected to a first air-intake passage, wherein the first air-intake passage is configured to provide air at a first set of characteristics; and  
 a second cylinder group fluidly connected to a second air-intake passage, wherein the second air-intake passage is configured to provide air at a second set of characteristics different from the first set of characteristics; and  
   an exhaust system including: 
 a first exhaust passage fluidly connected to the first cylinder group and a second exhaust passage fluidly connected to the second cylinder group;  
 an ammonia-producing catalyst disposed within the first exhaust passage and configured to convert at least a portion of a fluid in the first exhaust passage into ammonia; and  
 a merged exhaust passage configured to connect the first exhaust passage and the second exhaust passage downstream of the ammonia-producing catalyst to facilitate a reaction between ammonia and NOx to at least partially remove NOx from the merged exhaust passage.  
   
   
   
       17 . The machine of  claim 16 , wherein the first air-intake passage includes a valve configured to modify at least one characteristic of the first set of characteristics to permit the power source to produce substantially similar power output from a cylinder of the first cylinder group and a cylinder of the second cylinder group.  
   
   
       18 . The machine of  claim 16 , wherein the exhaust system further includes a turbo-compound operably associated with at least one of the first exhaust passage, the second exhaust passage and the merged exhaust passage.  
   
   
       19 . The machine of  claim 16 , wherein the machine further includes a forced-induction system operably associated with at least one of the first air-intake passage, the second air-intake passage, the first exhaust passage, the second exhaust passage, and the merged exhaust passage.  
   
   
       20 . The machine of  claim 19 , wherein the forced-induction system includes a component of at least one of a turbocharger and a supercharger.