Particulate trap regeneration system and method

Abstract

A particulate trap regeneration system has an exhaust pipe that is connected between an engine and a particulate trap and an air pump that is connected to the exhaust pipe near the engine. The exhaust pipe has a double-walled configuration where the exhaust travels within the pipe and air from the air pump travels within the space between the walls, capturing heat from the exhaust. This configuration also keeps the outside of the exhaust pipe cool, improving safety and durability. Because the air entering the trap is near the exhaust temperature, the burner requires less energy to raise the temperature of the particulates sufficiently to promote burning.

1 . A particulate trap system, comprising: 
 a particulate trap that traps particulates in exhaust from an engine;    an air supply for directing air to the particulate trap;    an exhaust pipe coupled to the particulate trap and connectable to the engine, wherein the exhaust pipe includes a first channel that carries exhaust toward the particulate trap and a second channel that carries air from the air supply toward the particulate trap, wherein the first channel and the second channel have a common wall that allows heat to transfer from the exhaust to the air and raise the temperature of the air sent to the particulate trap: and    a burner that heats the particulates in the particulate trap to regenerate the particulate trap.    
   
   
       2 . The particulate trap system of  claim 1 , wherein the air supply is one selected from the group consisting of an air pump, an engine boosting device, a brake compressor, and stored compressed air.  
   
   
       3 . The particulate trap system of  claim 2 , wherein the air pump is a mechanically-driven air pump.  
   
   
       4 . The particulate trap system of  claim 2 , further comprising a clutch that selectively controls operation of the air pump.  
   
   
       5 . The particular trap system of  claim 2 , wherein the air pump is an electrically-driven air pump.  
   
   
       6 . The particulate trap system of  claim 1 , wherein the exhaust pipe is a double-walled pipe having an inner wall and an outer wall.  
   
   
       7 . The particulate trap system of  claim 6 , further comprising at least one heat transfer fin extending substantially radially between the inner wall and the outer wall.  
   
   
       8 . The particulate trap system of  claim 6 , wherein the second channel is a space between the inner wall and the outer wall, and wherein the air supply directs air into the second channel.  
   
   
       9 . The particulate trap system of  claim 1 , further comprising at least one fuel injector that injects fuel into the particulate trap.  
   
   
       10 . An engine system comprising: 
 an engine having an exhaust manifold;    a particulate trap that traps particulates in exhaust emitted through the exhaust manifold;    an air supply for directing air to the particulate trap;    an exhaust pipe connecting the exhaust manifold to the particulate trap, wherein the exhaust pipe includes a first channel that carries exhaust toward the particulate trap and a second channel that carries air from the air supply toward the particulate trap, wherein the first channel and the second channel have a common wall to allow the heat transfer from the exhaust to the air and raise the temperature of the air sent to the particulate trap and    a burner that heats the particulates in the particulate trap to regenerate the particulate trap.    
   
   
       11 . The particulate trap system of  claim 10 , wherein the air supply is one selected from the group consisting of an air pump, an engine boosting device, a brake compressor, and stored compressed air.  
   
   
       12 . The engine system of  claim 10 , wherein the air supply is a mechanically-driven air pump coupled to the engine.  
   
   
       13 . The engine system of  claim 12 , further comprising a clutch that selectively connects and disconnects the air pump with the engine.  
   
   
       14 . The engine system of  claim 10 , wherein the exhaust pipe is a double-walled pipe having an inner wall and an outer wall.  
   
   
       15 . The particulate trap system of  claim 14 , further comprising at least one heat transfer fin extending substantially radially between the inner wall and the outer wall.  
   
   
       16 . The engine system of  claim 14 , wherein the second channel is a space between the inner wall and the outer wall, and wherein the air supply directs air into the second channel.  
   
   
       17 . The engine system of  claim 10 , further comprising at least one fuel injector that injects fuel into the particulate trap.  
   
   
       18 . The engine system of  claim 10 , further comprising a check valve connected to the exhaust pipe.  
   
   
       19 . A method of regenerating a particulate trap in an engine system, comprising: 
 directing air and exhaust into the particulate trap through an exhaust pipe having two channels with a common wall, wherein the air is carried in a first channel and the exhaust is carried in a second channel, and wherein the air absorbs heat in the exhaust through the common wall; and    heating particulates in the particulate trap to burn the particulates.    
   
   
       20 . The method of  claim 19 , further comprising adding at least one of a fuel and a catalyst to the particulate trap.