Exhaust treatment system having particulate filters

Abstract

An exhaust treatment system for a power source has an air induction system and an exhaust system. The exhaust system has a first particulate filter and a second particulate filter disposed in series with the first particulate filter. The exhaust treatment system further has a recirculation system configured to draw at least a portion of an exhaust flow from between the first particulate filter and the second particulate filter and to direct the at least a portion of the exhaust flow to the air induction system.

1 . An exhaust treatment system for a power source, comprising: 
 an air induction system;    an exhaust system, including: 
 a first particulate filter; and  
 a second particulate filter disposed in series with the first particulate filter; and  
   a recirculation system configured to draw at least a portion of an exhaust flow from between the first particulate filter and the second particulate filter and to direct the at least a portion of the exhaust flow to the air induction system.    
   
   
       2 . The exhaust treatment system of  claim 1 , wherein the recirculation system further includes a recirculation valve configured to regulate the flow of the at least a portion of the exhaust flow.  
   
   
       3 . The exhaust treatment system of  claim 2 , wherein the air induction system includes an induction valve configured to regulate the flow of inlet air into the air induction system.  
   
   
       4 . The exhaust treatment system of  claim 3 , wherein a flow characteristic of the recirculation valve is related to a flow characteristic of the induction valve.  
   
   
       5 . The exhaust treatment system of claims  1 , wherein the recirculation system further includes a recirculation particulate filter configured to remove particulates from the at least a portion of the exhaust flow.  
   
   
       6 . The exhaust treatment system of  claim 5 , wherein the recirculation particulate filter includes a catalyst.  
   
   
       7 . The exhaust treatment system of  claim 5 , wherein the recirculation particulate filter includes a means for active regeneration.  
   
   
       8 . The exhaust treatment system of  claim 1 , wherein the first particulate filter includes a coarse mesh.  
   
   
       9 . The exhaust treatment system of  claim 1 , wherein the second particulate filter has a greater particulate trapping efficiency than the first particulate filter.  
   
   
       10 . The exhaust treatment system of  claim 1 , wherein at least one of the first and second particulate filters includes a catalyst.  
   
   
       11 . The exhaust treatment system of  claim 1 , wherein at least one of the first and second particulate filters includes a means for active regeneration.  
   
   
       12 . The exhaust treatment system of  claim 1 , wherein: 
 the air induction system further includes at least one compressor;    the exhaust system further includes at least one turbine connected to the at least one compressor and disposed downstream of the first particulate filter; and    the recirculation system draws the at least a portion of an exhaust flow from downstream of the at least one turbine and directs at least a portion of the exhaust flow to the air induction system upstream of the at least one compressor.    
   
   
       13 . A method of operating an exhaust treatment system for a power source, the method comprising: 
 directing air into the power source;    directing an exhaust flow away from the power source;    filtering out particulates entrained within the exhaust flow with a first particulate filter;    directing a first portion of the exhaust flow from downstream of the first particulate filter into the power source;    directing a second portion of the exhaust flow from downstream of the first particulate filter to a second particulate filter; and    filtering particulates out of the exhaust flow with the second particulate filter.    
   
   
       14 . The method of  claim 13 , further including regulating the flow of the first portion of the exhaust flow directed into the power source.  
   
   
       15 . The method of  claim 14 , further including regulating the flow of air into the power source.  
   
   
       16 . The method of  claim 15 , wherein a flow characteristic of the air regulated into the power source is related to a flow characteristic of the first portion of the exhaust flow regulated into the power source.  
   
   
       17 . The method of  claim 16 , further including filtering the first portion of the exhaust flow with a recirculation particulate filter.  
   
   
       18 . The method of  claim 17 , further including passively regenerating the recirculation particulate filter with a catalyst.  
   
   
       19 . The method of  claim 17 , further including actively regenerating the recirculation particulate filter.  
   
   
       20 . The method of  claim 13 , wherein the second particulate filter has a greater particulate trapping efficiency than the first particulate filter.  
   
   
       21 . The method of  claim 13 , further including passively regenerating at least one of the first and second particulate filters with a catalyst.  
   
   
       22 . The method of  claim 13 , further including actively regenerating at least one of the first and second particulate filters.  
   
   
       23 . An exhaust treatment system for a power source, comprising: 
 an air induction system, including at least one compressor;    an exhaust system, including: 
 a particulate filter; and  
 at least one turbine connected to the at least one compressor and disposed downstream of the particulate filter; and  
   a recirculation system configured to draw at least a portion of an exhaust flow from downstream of the at least one turbine and to direct the at least a portion of an exhaust flow to the air induction system upstream of the at least one compressor.    
   
   
       24 . The exhaust treatment system of  claim 23 , wherein the recirculation system further includes a recirculation valve configured to regulate the flow of the at least a portion of an exhaust flow into the power source.  
   
   
       25 . The exhaust treatment system of  claim 24 , wherein the air induction system includes an induction valve configured to regulate the flow of inlet air into the power source.  
   
   
       26 . The exhaust treatment system of  claim 25 , wherein a flow characteristic of the recirculation valve is related to a flow characteristic of the induction valve.  
   
   
       27 . The exhaust treatment system of claims  23 , wherein the recirculation system further includes a recirculation particulate filter configured to remove particulates from the at least a portion of an exhaust flow.  
   
   
       28 . The exhaust treatment system of  claim 27 , wherein the recirculation particulate filter includes a catalyst.  
   
   
       29 . The exhaust treatment system of  claim 27 , wherein the recirculation particulate filter includes a means for active regeneration.  
   
   
       30 . The exhaust treatment system of  claim 23 , wherein the particulate filter includes a coarse mesh.  
   
   
       31 . The exhaust treatment system of  claim 23 , wherein the particulate filter includes a catalyst.  
   
   
       32 . The exhaust treatment system of  claim 23 , wherein the particulate filter includes a means for active regeneration.  
   
   
       33 . A power system, comprising: 
 a power source operable to produce an exhaust flow;    an air induction system configured to direct an airflow into the power source, the air induction system including: 
 an induction valve configured to regulate the flow of inlet airflow into the power source; and  
 at least one compressor configured to pressurize the airflow;  
   an exhaust system, including: 
 a first particulate filter having a coarse mesh;  
 a second particulate filter disposed in series with the first particulate filter and having a greater particulate trapping efficiency than the first particulate filter, at least one of the first and second particulate filters including a catalyst; and  
 at least one turbine connected to the at least one compressor and disposed downstream of the first particulate filter; and  
   a recirculation system configured to draw at least a portion of the exhaust flow from between the first particulate filter and the second particulate filter downstream of the at least one turbine and to direct the at least a portion of the exhaust flow to the air induction system upstream of the at least one compressor, the recirculation system including a recirculation valve configured to regulate the flow of the at least a portion of the exhaust flow, wherein a flow characteristic of the recirculation valve is related to a flow characteristic of the induction valve.    
   
   
       34 . The exhaust treatment system of claims  33 , wherein the recirculation system further includes a recirculation particulate filter configured to remove particulates from the at least a portion of the exhaust flow.  
   
   
       35 . The exhaust treatment system of  claim 34 , wherein the recirculation particulate filter includes a catalyst.  
   
   
       36 . The exhaust treatment system of  claim 34 , wherein the recirculation particulate filter includes a means for active regeneration.  
   
   
       37 . The exhaust treatment system of  claim 33 , wherein at least one of the first and second particulate filters include a means for active regeneration.