Particle burner including a catalyst booster for exhaust systems

Abstract

An exemplary exhaust cleaner comprises a reverse flow heat exchanger and a gas permeable catalyst. The reverse flow heat exchanger includes two interleaved ducts that are spiral-wound around a central volume. The gas permeable catalyst is disposed within the central volume and separates the central volume into first and second regions. The first duct of the reverse flow heat exchanger opens into the first region, and the second duct opens into the second region. The heat generated at the catalyst by the catalysis of incomplete combustion products within the exhaust heats the exhaust within the central volume to a temperature sufficient to burn particulates within the exhaust. The heat generated within the central volume by the catalysis and the combustion of any particulates is carried by the exhaust into the second duct where the heat is transferred to the cooler exhaust within the first duct.

1 . An exhaust cleaner, comprising:
 a reverse flow heat exchanger including a first duct interleaved with a second duct, each duct spiral-wound around a central volume, the first and second ducts in fluid communication with each other across the central volume; and   a gas permeable catalyst disposed within the central volume and separating the central volume into first and second regions, the first duct opening into the first region and the second duct opening into the second region.   
   
   
       2 . The exhaust cleaner of  claim 1  wherein the catalyst comprises a substrate and a catalytic material. 
   
   
       3 . The exhaust cleaner of  claim 1  wherein the central volume further comprises a heating element. 
   
   
       4 . The exhaust cleaner of  claim 1  wherein the central volume further comprises a radiation source. 
   
   
       5 . The exhaust cleaner of  claim 1  further comprising an inlet chamber and an outlet chamber, wherein the inlet chamber is in fluid communication with the first duct and the outlet chamber is in fluid communication with the second duct. 
   
   
       6 . The exhaust cleaner of  claim 5  wherein the inlet chamber includes vanes that protrude into the inlet chamber. 
   
   
       7 . The exhaust cleaner of  claim 5  wherein the outlet chamber includes vanes extending outward. 
   
   
       8 . A vehicle comprising:
 an internal combustion engine; and   an exhaust system configured to receive exhaust from the internal combustion engine, the exhaust system including an exhaust cleaner comprising:
 a reverse flow heat exchanger including a first duct interleaved with a second duct, each duct spiral-wound around a central volume, the first and second ducts in fluid communication with each other across the central volume, and 
 a gas permeable catalyst disposed within the central volume and separating the central volume into first and second regions, the first duct opening into the first region and the second duct opening into the second region. 
   
   
   
       9 . The vehicle of  claim 8  wherein the catalyst comprises a substrate and a catalytic material. 
   
   
       10 . The vehicle of  claim 8  wherein the central volume further comprises a heating element. 
   
   
       11 . The vehicle of  claim 8  wherein the central volume further comprises a radiation source. 
   
   
       12 . The vehicle of  claim 8  wherein the exhaust cleaner further comprises an inlet chamber and an outlet chamber, wherein the inlet chamber is in fluid communication with the first duct and the outlet chamber is in fluid communication with the second duct. 
   
   
       13 . The vehicle of  claim 12  wherein the inlet chamber includes vanes that protrude into the inlet chamber. 
   
   
       14 . The vehicle of  claim 12  wherein the outlet chamber includes vanes extending outward. 
   
   
       15 . A method for cleaning vehicle exhaust, the method comprising:
 heating exhaust from an internal combustion engine in a first duct of a reverse flow heat exchanger;   passing the exhaust from the first duct, through a gas permeable catalyst, and into a second duct of the reverse flow heat exchanger, where catalysis of incomplete combustion products at the catalyst heats the catalyst and further heats the exhaust; and   cooling the exhaust within the second duct by transferring heat to the first duct.   
   
   
       16 . The method of  claim 15  wherein the ducts of the reverse flow heat exchanger are interleaved. 
   
   
       17 . The method of  claim 15  wherein the ducts of the reverse flow heat exchanger are spiral-wound. 
   
   
       18 . The method of  claim 15  further comprising monitoring a temperature of the catalyst. 
   
   
       19 . The method of  claim 18  further comprising employing a heating means to heat the exhaust whenever the temperature of the catalyst is below a threshold.