Exhaust gas post processing method

Abstract

An exhaust gas post processing method may include determining whether a driving condition is included in an area for monitoring a rapid-heat-up (RHU) logic process that is used to quickly raise a temperature of exhaust gas passing an exhaust line, detecting on/off signal that performs or stops the rapid-heat-up logic process, determining whether an injection signal for performing the rapid-heat-up logic process is activated or not, detecting error of components for performing the rapid-heat-up logic process, and detecting the temperature of the exhaust during the rapid-heat-up logic process and comparing the detected temperature with a modeled value. Accordingly, malfunction of the rapid-heat-up logic process is prevented before hand to realize the rapid-heat-up logic process securely, and the malfunction by the error signal is informed to the driver such that the on board diagnosis function is improved.

1 . An exhaust gas post processing method, comprising:
 determining whether a driving condition requires a rapid-heat-up (RHU) logic process to quickly raise a temperature of exhaust gas passing through an exhaust line;   detecting an on/off signal that performs or stops the rapid-heat-up logic process;   determining whether an injection signal for performing the rapid-heat-up logic process is activated or not;   detecting an error status of one or more components for performing the rapid-heat-up logic process; and   detecting the temperature of the exhaust during the rapid-heat-up logic process and comparing the detected temperature with a modeled value.   
     
     
         2 . The exhaust gas post processing method of  claim 1 , further comprising:
 outputting an error signal when the detected temperature that is raised by the rapid-heat-up logic process various from the modeled value.   
     
     
         3 . The exhaust gas post processing method of  claim 2 , further comprising:
 accumulating the error signal, and   storing the accumulated value and activating a rapid-heat-up logic warning lamp, if the accumulated value exceeds a predetermined value.   
     
     
         4 . The exhaust gas post processing method of  claim 1 , wherein the driving condition for entering into the rapid-heat-up logic process is determined based on an atmospheric pressure, a vehicle speed, an engine speed, an intake air temperature, a coolant temperature, a gear speed, and a fuel injection amount. 
     
     
         5 . The exhaust gas post processing method of  claim 4 , wherein if the condition for entering into the rapid-heat-up logic process is satisfied, a post injection amount for performing the rapid-heat-up logic process is determined based on the engine speed and the fuel injection amount to inject the fuel. 
     
     
         6 . The exhaust gas post processing method of  claim 1 , wherein one of the components includes an injector injecting the fuel and a temperature sensor detecting the temperature of the exhaust gas in a step of the detecting the error of the component. 
     
     
         7 . The exhaust gas post processing method of  claim 1 , wherein:
 a diesel oxidation catalyst oxidizes harmful materials included in the exhaust gas;   a diesel particulate filter that filters particulate matters included in the exhaust gas;   a dosing module that injects reducing agent into the exhaust gas passing the exhaust line; and   a selective catalyst reduction unit (SCR) that uses the reducing agent injected by the dosing module to reduce/oxidize nitrogen oxide included in the exhaust gas are sequentially disposed on the exhaust line.   
     
     
         8 . The exhaust gas post processing method of  claim 7 , wherein:
 a temperature sensor detects temperatures of a rear side of the engine, a front side of the diesel oxidation catalyst, a front side of the diesel particulate filter, and a front side of the selective catalyst reduction unit.