Stoichiometric engine system utilizing reformed exhaust gas

Abstract

A power system is provided having an engine configured to combust a substantially stoichiometric air/fuel mixture and produce a flow of exhaust. The power system also has an exhaust passageway fluidly connected to the engine. In addition, the power system has a catalytic device situated within the exhaust passageway. Furthermore, the system has an exhaust gas recirculation loop fluidly connected to the exhaust passageway. The system further has a steam fuel reformer situated within the exhaust gas recirculation loop.

1 . A power system, comprising:
 an engine configured to combust a substantially stoichiometric air/fuel mixture and produce a flow of exhaust;   an exhaust passageway fluidly connected to the engine;   a catalytic device situated within the exhaust passageway;   an exhaust gas recirculation loop fluidly connected to the exhaust passageway downstream of the catalytic device; and   a steam fuel reformer situated within the exhaust gas recirculation loop.   
   
   
       2 . The power system of  claim 1 , further including a fluid passageway fluidly connected to the exhaust gas recirculation loop upstream of the steam fuel reformer, the fluid passageway being configured to direct at least a portion of the fuel to be combusted by the engine through the steam fuel reformer. 
   
   
       3 . The power system of  claim 2 , wherein the fluid passageway is configured to direct all of the fuel to be combusted by the engine through the steam fuel reformer. 
   
   
       4 . The power system of  claim 1 , wherein the catalytic device includes a 3-way catalyst. 
   
   
       5 . The power system of  claim 1 , further including a heat exchanger situated within the exhaust recirculation loop downstream of the steam fuel reformer. 
   
   
       6 . The power system of  claim 1 , wherein fuel in the air/fuel mixture entering the engine is natural gas. 
   
   
       7 . A power system, comprising:
 an engine configured to combust a substantially stoichiometric air/fuel mixture and produce a flow of exhaust;   an exhaust passageway fluidly connected to the engine;   a catalytic device situated within the exhaust passageway;   an exhaust gas recirculation loop fluidly connected to the exhaust passageway upstream of the catalytic device; and   a steam fuel reformer situated within the exhaust gas recirculation loop.   
   
   
       8 . The power system of  claim 7 , further including a fluid passageway fluidly connected to the exhaust gas recirculation loop upstream of the steam fuel reformer, the fluid passageway being configured to direct at least a portion of the fuel to be combusted by the engine through the steam fuel reformer. 
   
   
       9 . The power system of  claim 8 , wherein the fluid passageway is configured to direct all of the fuel to be combusted by the engine through the steam fuel reformer. 
   
   
       10 . The power system of  claim 7 , wherein the catalytic device includes a 3-way catalyst. 
   
   
       11 . The power system of  claim 7 , further including a heat exchanger situated within the exhaust recirculation loop downstream of the steam fuel reformer. 
   
   
       12 . A method for treating exhaust gas, comprising:
 combusting a substantially stoichiometric air/fuel mixture;   catalyzing an exhaust gas generated by the combustion of the air/fuel mixture;   redirecting at least a portion of the exhaust gas so that the redirected exhaust gas is combusted with the air/fuel mixture; and   enriching the redirected exhaust gas/fuel mixture.   
   
   
       13 . The method of  claim 12 , further including catalyzing the exhaust gas before redirecting at least a portion of the exhaust gas. 
   
   
       14 . The method of  claim 12 , further including catalyzing the exhaust gas after a portion of the exhaust gas has been redirected. 
   
   
       15 . The method of  claim 12 , further including mixing at least a portion of the fuel to be combusted with the redirected exhaust gas before the redirected exhaust gas mixes with air. 
   
   
       16 . The method of  claim 12 , directing the fuel to be combusted in such a manner that all of the fuel to be combusted mixes with the redirected exhaust gas before being mixed with air. 
   
   
       17 . The method of  claim 12 , wherein enriching the redirected exhaust gas includes increasing the amount of hydrogen and carbon monoxide in the redirected exhaust gas. 
   
   
       18 . The method of  claim 17 , wherein enriching the redirected exhaust gas further includes decreasing the amount of water in the redirected exhaust gas. 
   
   
       19 . The method of  claim 12 , wherein catalyzing the exhaust gas includes increasing the amount of carbon dioxide, water, and nitrogen. 
   
   
       20 . The method of  claim 19 , wherein catalyzing the exhaust gas further includes decreasing the amount of hydrocarbons, carbon monoxide, and nitrogen oxides.