Exhaust Gas-Aftertreatment Device and Control Method Thereof

Abstract

The present invention relates to an exhaust gas-aftertreatment device and a control method thereof. More specifically, the invention relates to an exhaust gas-aftertreatment device, which employs a burner and a metal filter, so that the filter can be regenerated within a short time at high temperature, and wherein the burner is operated when the vehicle is idling, and wherein the filter can be efficiently regenerated by forming a flame in a stable manner using a dispersion means, and which furthermore has enhanced durability, and to a method for controlling the same.

1 . An exhaust gas-aftertreatment device for reducing exhaust gas emission from a diesel engine, comprising:
 a body which has, on one outer side, an exhaust gas inlet connected with an exhaust pipe to introduce the exhaust gas into the system, and on the other side, an exhaust gas outlet for emitting purified exhaust gas;   a burner including a fuel injection means, placed adjacent to the exhaust gas inlet of the body and having a nozzle section provided at an end thereof to inject atomized fuel, an ignition means for igniting the injected fuel, and a dispersion means for guiding the fuel injected through the fuel injection means and the exhaust gas introduced through the exhaust gas inlet to a metal filter;   the metal filter provided at the rear end of the burner to burn organic or particulate matter in the exhaust gas; and   a control means for controlling operation of the burner and determining a state of the system.   
     
     
         2 . The exhaust gas-aftertreatment device of  claim 1 , wherein the metal filter is made of Fecalloy. 
     
     
         3 . The exhaust gas-aftertreatment device of  claim 2 , wherein the surface of the metal filter is heat-treated. 
     
     
         4 . The exhaust gas-aftertreatment device of  claim 3 , wherein the heat treatment of the surface is carried out in an air atmosphere at a temperature of 900 to 1000° C. to form an aluminum oxide film on the surface. 
     
     
         5 . The exhaust gas-aftertreatment device of  claim 1 , wherein the dispersion means is designed such that the diameter thereof becomes wider from the fuel injection means in a direction of the metal filter, and a plurality of openings are formed in the dispersion means such that the exhaust gas introduced through the exhaust gas inlet goes through the openings to an inside of the dispersion means and effectively mixes with the fuel in the dispersion means, and a flame is formed in a stable manner. 
     
     
         6 . The exhaust gas-aftertreatment device of  claim 5 , wherein the openings are formed at an angle in a tangential direction of the dispersion means, such that the exhaust gas that went through the openings into the dispersion means has a specific flow pattern. 
     
     
         7 . The exhaust gas-aftertreatment device of  claim 5 , wherein the exhaust gas-aftertreatment device further comprises an air injection means for injecting air into the nozzle section of the fuel injection means. 
     
     
         8 . The exhaust gas-aftertreatment device of  claim 5 , wherein the control means serves to determine the state of the system with the information provided by a pressure sensor located at the front end of the exhaust gas-aftertreatment device or the metal filter, two temperature sensors measuring temperatures of front and rear ends of the metal filter, RPM sensor of the engine, or GPS (Global Positioning System) information. 
     
     
         9 . The exhaust gas-aftertreatment device of  claim 1 , wherein the exhaust gas-aftertreatment device further comprises an alarm means for notifying of a sensed system state or emergency determined by the control means. 
     
     
         10 . A method for controlling the exhaust gas-aftertreatment device of any one of  claims 1 , comprising:
 an active regeneration-determining step for determining whether operation of the burner is required, after operation of the engine;   an alarm signal-transmitting step for notifying an alarm signal to a vehicle driver with an alarm means, if it is determined in the active regeneration-determining step that operation of the burner is required;   an idling state-determining step for determining whether the vehicle is in an idling state, after the alarm signal-transmitting step;   an active regeneration step for operating the burner to perform active regeneration, if it is determined in the idling state-determining step that the vehicle is in the idling state and if a user's instruction to do regeneration operation is input; and   an active regeneration end step for stopping the burner to end the active regeneration, after performing the active regeneration step.   
     
     
         11 . The method of  claim 10 , wherein it is determined in the active regeneration-determining step that, if a pressure measured by a pressure sensor is higher than a first pressure criteria or if an average pressure measured by the pressure sensor for a specific period of time is higher than a second pressure criteria, the burner should be operated. 
     
     
         12 . The method of  claim 11 , wherein the first pressure criteria is 150-250 mbar, and the second pressure criteria is 75-150 mbar. 
     
     
         13 . The method of  claim 11 , wherein the method further comprises a system state-checking step for checking the state of the system, after the operation of the engine. 
     
     
         14 . The method of  claim 13 , wherein the active regeneration-determining step is performed again when the engine is operated after the active regeneration end step. 
     
     
         15 . The method of  claim 10 , wherein the amount of fuel injected into the burner in the active regeneration step is controlled such that a temperature of a front end of the metal filter is in the range of 600 to 900° C.