Rapid heater for emission control device

Abstract

An emission control device having a catalyst matrix, a microwave heater and a microwave energy reflective sleeve which substantially surrounds an outer surface of the matrix is provided. In one example, power is supplied to the microwave generator only as long as the temperature of the catalyst matrix is less than the activation temperature of the emission control reactions. The microwave energy reflective sleeve may reflect and confine substantially all of a microwave energy received from a microwave generator and waveguide, improving the operability of the emission control device and reducing the light-off time of the emission control reactions.

1 . An emission control device, comprising:
 a can;   a matrix, the matrix having an inlet end, an outlet end, and an outer surface therebetween;   a microwave energy reflective sleeve substantially surrounding the outer surface, where the sleeve and matrix are retained in the can.   
   
   
       2 . The emission control device of  claim 1 , wherein the matrix further comprises a washcoated monolith. 
   
   
       3 . The emission control device of  claim 2 , wherein a microwave energy reflective mesh end wall is adjacent to each of the inlet end and the outlet end of the matrix. 
   
   
       4 . The emission control device of  claim 1 , wherein the can further comprises an interface configured to be coupled to a waveguide. 
   
   
       5 . The emission control device of  claim 1 , wherein the sleeve further comprises a flexible and shock-resistant material configured to protect the matrix. 
   
   
       6 . An emission control system for a vehicle, comprising:
 a microwave generator;   a waveguide configured to receive microwave energy from the microwave generator; and   an emission control device configured to receive microwave energy from the waveguide, the emission control device further comprising:
 a can; 
 a matrix having an inlet and an outlet; 
 a microwave energy reflective sleeve substantially surrounding the matrix, wherein the sleeve and matrix are retained in the can; and 
 at least two microwave energy reflecting mesh end walls respectively coupled to the inlet and outlet of the matrix. 
   
   
   
       7 . The emission control system of  claim 6 , further comprising a controller configured to adjust microwave energy output of the microwave generator responsive to an exhaust condition of an exhaust stream from an internal combustion engine. 
   
   
       8 . The emission control system of  claim 7 , further comprising a controller configured to adjust microwave energy output of the microwave generator responsive to a temperature of the matrix. 
   
   
       9 . The emission control system of  claim 8 , wherein the microwave generator supplies microwave energy to the emission control device when the temperature of the matrix is below an activation temperature of an active catalyst particle on a surface of the matrix. 
   
   
       10 . The emission control system of  claim 6 , wherein the matrix is a catalytically active monolith. 
   
   
       11 . The emission control system of  claim 6 , the waveguide further comprising a fused quartz plug adjacent an interface configured to be coupled to the can. 
   
   
       12 . An emission control system for treating exhaust gasses of an internal combustion engine, comprising:
 a microwave system comprising at least:
 a microwave energy generator, and 
 a waveguide configured to receive microwave energy from the generator, an emission control device coupled to the microwave heater, the emission control device including a can; a matrix, the matrix having an inlet end, and outlet end, and an outer surface therebetween; and a microwave energy reflective sleeve substantially surrounding the outer surface, where the mesh and matrix are retained in the can; and 
 a controller configured to adjust the microwave energy generator responsive to a condition of the exhaust gasses from the internal combustion engine. 
   
   
   
       13 . The emission control system of  claim 12 , wherein the controller is further configured to adjust the generator responsive to an exhaust condition, wherein the controller is further configured to operate the generator at a frequency of 2.45±0.20 GHz. 
   
   
       14 . The emission control system of  claim 12 , wherein the matrix further comprises a washcoated monolith, wherein a microwave energy reflective mesh end wall is adjacent to each of the inlet end and the outlet end of the matrix, and wherein the can further comprises an interface configured to be coupled to the waveguide. 
   
   
       15 . The emission control system of  claim 12 , wherein the sleeve further comprises a flexible and shock-resistant material configured to protect the matrix. 
   
   
       16 . The emission control system of  claim 12 , wherein the controller is further configured to adjust microwave energy output of the microwave generator responsive to a temperature of the matrix. 
   
   
       17 . The emission control system of  claim 12 , wherein the controller is further configured to adjust the operation of the generator responsive to a condition of an internal combustion engine. 
   
   
       18 . The emission control system of  claim 17 , wherein the condition of the internal combustion engine includes one or more of an exhaust gas recirculation ratio, an engine speed, a spark timing, a fuel injection amount, or a driver tip-in. 
   
   
       19 . The emission control system of  claim 12 , wherein the waveguide further comprises a fused quartz plug adjacent the circumferential surface of the emission control device. 
   
   
       20 . The emission control system of  claim 19 , wherein the sleeve further comprises a microwave energy reflective mesh.