Method for Heating a SCR System

Abstract

Process for heating a urea component of a SCR system comprising besides said component, a temperature sensor, a heating device in the component, according to which: 1. the temperature (Tcpt) of the liquid in the component is determined and compared to a 1 st setpoint (T 0 ); 2. if the temperature (Tcpt) is greater than the 1 st setpoint (T 0 ), step 1 is repeated; 3. if the temperature (Tcpt) is less than or equal to the 1 st setpoint (T 0 ), the heating device is actuated, 4. the time during which the heating device is actuated is measured and the heating device is stopped if this time is greater than a time t 1 ; 5. the temperature (Tcpt) is determined after a time t 2 and compared to a 2 nd setpoint (T 1 with T 1 >T 0 ); if the temperature (Tcpt) is less than or equal to the 2 nd setpoint (T 1 ) the heating device is actuated and step 4 is repeated; 6. if the temperature (Tcpt) is greater than the 2 nd septoint (T 1 ), the heating device is stopped and step 1 is repeated.

1 . A process for heating a urea component of a Selective Catalytic Reduction (SCR) system comprising besides said component, a temperature sensor, and a heating device in the component, said process comprising the following steps:
 step 1: the temperature (Tcpt) of the liquid in the component is determined and compared to a first setpoint (T 0 );   step 2: if the temperature (Tcpt) is greater than the first setpoint (T 0 ), step 1 is repeated;   step 3: if the temperature (Tcpt) is less than or equal to the first setpoint (T 0 ), the heating device is actuated,   step 4: the time during which the heating device is actuated is measured and the heating device is stopped if this time is greater than a time t 1 ;   step 5: the temperature (Tcpt) is determined after a time t 2  and compared to a second setpoint (T 1  with T 1 >T 0 ); if the temperature (Tcpt) is less than or equal to the second setpoint (T 1 ), the heating device is actuated and step 4 is repeated; and   step 6: if the temperature (Tcpt) is greater than the second septoint (T 1 ), the heating device is stopped and step 1 is repeated.   
     
     
         2 . The process according to  claim 1 , wherein the liquid in the component is urea. 
     
     
         3 . The process according to  claim 1 , wherein the component is a tank. 
     
     
         4 . The process according to  claim 1 , wherein the heating device is a flexible heater. 
     
     
         5 . The process according to  claim 2 , wherein the first setpoint (T 0 ) is greater than or equal to a freezing temperature of the urea. 
     
     
         6 . The process according to the preceding claim, wherein the first setpoint (T 0 ) is greater than or equal to a freezing temperature that corresponds to the concentration of the urea after ageing of the urea. 
     
     
         7 . The process according to  claim 1  wherein the time t 1  corresponds to the time necessary for the temperature (Tcpt) to exceed a safeguard temperature (Tsaf) with Tsaf<Tover where Tover is an overheating temperature.