Method and apparatus for piezoelectric injection of agent into exhaust gas for use with emission abatement device

Abstract

An apparatus comprises an exhaust gas system and a piezoelectric device. The piezoelectric device is configured to inject an agent into the exhaust gas system for delivery to an emission abatement device of the exhaust gas system. An associated method is disclosed.

1 . A method, comprising the steps of: 
 operating a piezoelectric device so as to inject an agent into an exhaust gas stream, and    advancing the injected agent to an emission abatement device.    
   
   
       2 . The method of  claim 1 , wherein the operating step comprises vibrating the piezoelectric device in an agent supply passageway.  
   
   
       3 . The method of  claim 1 , wherein the operating step comprises operating a controller so as to control operation of the piezoelectric device.  
   
   
       4 . The method of  claim 1 , wherein the operating step comprises operating the piezoelectric device according to a time-based scheme.  
   
   
       5 . The method of  claim 1 , wherein the operating step comprises operating the piezoelectric device in response to sensing a parameter associated with the exhaust gas stream.  
   
   
       6 . The method of  claim 5 , wherein the sensing step comprises sensing NOx in the exhaust gas stream.  
   
   
       7 . The method of  claim 5 , wherein the sensing step comprises sensing a pressure in the exhaust gas stream.  
   
   
       8 . The method of  claim 1 , wherein: 
 the operating step comprises operating the piezoelectric device so as to inject hydrocarbon fuel into the exhaust gas stream, and    the advancing step comprises advancing the injected hydrocarbon fuel to the emission abatement device.    
   
   
       9 . The method of  claim 8 , wherein the advancing step comprises advancing the injected hydrocarbon fuel to a NOx trap.  
   
   
       10 . The method of  claim 8 , wherein the advancing step comprises advancing the injected hydrocarbon fuel to a particulate abatement device.  
   
   
       11 . The method of  claim 1 , wherein: 
 the operating step comprises operating the piezoelectric device so as to inject urea into the exhaust gas stream, and    the advancing step comprises advancing the injected urea to a selective catalytic reduction device.    
   
   
       12 . An apparatus, comprising: 
 an exhaust gas system comprising an emission abatement device, and    a piezoelectric device configured to inject an agent into the exhaust gas system for delivery of the agent to the emission abatement device.    
   
   
       13 . The apparatus of  claim 12 , wherein the piezeoelectric device is positioned in an agent supply passageway to inject the agent in response to vibration of the piezoelectric device.  
   
   
       14 . The apparatus of  claim 12 , further comprising a controller electrically coupled to the piezoelectric device.  
   
   
       15 . The apparatus of  claim 14 , wherein the controller is configured to operate the piezoelectric device according to a time-based scheme.  
   
   
       16 . The apparatus of  claim 14 , further comprising a sensor fluidly coupled to the exhaust system, wherein the controller is electrically coupled to the sensor to operate the piezoelectric device in response to operation of the sensor.  
   
   
       17 . The apparatus of  claim 16 , wherein the sensor is one of a NOx sensor and a pressure sensor.  
   
   
       18 . The apparatus of  claim 11 , wherein the emission abatement device comprises a NOx trap fluidly coupled to the piezoelectric device to receive the agent injected thereby.  
   
   
       19 . The apparatus of  claim 15 , wherein the emission abatement device comprises a particulate abatement device fluidly coupled to the piezoelectric device to receive the agent injected thereby.  
   
   
       20 . The apparatus of  claim 11 , wherein the emission abatement device comprises a selective catalytic reduction device fluidly coupled to the piezoelectric device to receive the agent injected thereby.