Method of regenerating a particulate filter

Abstract

A method of regenerating a particulate filter is disclosed. The method involves heating the particulate filter to an intermediate temperature, and maintaining the particulate filter at the intermediate temperature until substantial temperature equilibrium is reached. The particulate filter is then heated to a regeneration temperature higher than the intermediate temperature.

1 . A method of regenerating a particulate filter comprising:
 triggering a regeneration process;   determining a value indicative of an initial temperature of the particulate filter;   comparing the initial temperature to an intermediate temperature;   preheating the particulate filter to the intermediate temperature;   maintaining the particulate filter at the intermediate temperature for a predetermined period of time; and   heating the particulate filter to a regeneration temperature higher than the intermediate temperature.   
   
   
       2 . The method of  claim 1 , wherein the triggering of the regeneration process includes triggering regeneration of the particulate filter when a pressure drop across the particulate filter exceeds a threshold pressure drop. 
   
   
       3 . The method of  claim 1 , wherein the triggering of the regeneration process includes triggering regeneration of the particulate filter when a time between two successive regeneration events exceeds a threshold time duration. 
   
   
       4 . The method of  claim 1 , wherein the triggering of the regeneration process includes triggering regeneration of the particulate filter based upon a mathematical model estimating a particulate matter loading of the particulate filter. 
   
   
       5 . The method of  claim 1 , wherein the determination of the value includes measuring an inlet temperature and an outlet temperature of the particulate filter. 
   
   
       6 . The method of  claim 5 , wherein the determination of the value includes computing an overall temperature of the particulate filter based on the inlet temperature and the outlet temperature. 
   
   
       7 . The method of  claim 1 , wherein the determination of the value includes determining a temperature variation between different regions within the particulate filter. 
   
   
       8 . The method of  claim 7 , wherein the triggering of the regeneration process includes triggering regeneration of the particulate filter based on the temperature variation within the particulate filter. 
   
   
       9 . The method of  claim 1 , wherein the comparison of the initial temperature to the intermediate temperature includes computing the intermediate temperature. 
   
   
       10 . The method of  claim 9 , wherein the computation of the intermediate temperature includes determining the intermediate temperature such that the stresses in the particulate filter due to heating the particulate filter from intermediate temperature to the regeneration temperature is below the strength of the particulate filter. 
   
   
       11 . The method of  claim 1 , wherein the maintaining of the particulate filter at the intermediate temperature includes holding the particulate at the intermediate temperature until the particulate filter substantially equilibrates at the intermediate temperature. 
   
   
       12 . The method of  claim 11 , wherein the holding of the particulate filter at the intermediate temperature includes holding the particulate filter at the intermediate temperature until multiple temperature sensor readings indicate that the particulate filter has substantially equilibrated at the intermediate temperature. 
   
   
       13 . The method of  claim 1 , wherein the preheating of the particulate filter to the intermediate temperature, and the heating of the particulate filter to the regeneration temperature includes heating an exhaust gases supplied to the particulate filter using a fuel driven burner located upstream of the particulate filter. 
   
   
       14 . The method of  claim 1 , wherein heating the particulate filter to a regeneration temperature includes heating the particulate filter to a temperature at which an accumulated particulate matter in the particulate filter begins burning. 
   
   
       15 . A method of regenerating a diesel particulate filter comprising:
 heating the particulate filter to an intermediate temperature;   maintaining the particulate filter at the intermediate temperature until substantial temperature equilibrium is reached; and   heating the particulate filter to a regeneration temperature higher than the intermediate temperature.   
   
   
       16 . The method of  claim 15 , wherein the heating of the particulate filter to the intermediate temperature and the heating of the particulate filter to the regeneration temperature includes heating exhaust gases supplied to the particulate filter. 
   
   
       17 . The method of  claim 16 , wherein the heating of the exhaust gases includes heating the exhaust gases using a fuel driven burner located upstream of the particulate filter. 
   
   
       18 . An exhaust system of an engine comprising;
 a particulate filter through which exhaust gas flows;   one or more temperature sensors attached to the particulate filter, wherein the sensors are configured to measure a value indicative of a temperature of the particulate filter; and   a control system electrically connected to the sensors, wherein the control system is configured to:
 heat the particulate filter to an intermediate temperature that is higher than the overall temperature, 
 maintain the particulate filter at the intermediate temperature until a substantial temperature equilibrium is reached, and 
 heat the particulate filter to a regeneration temperature that is higher than the intermediate temperature. 
   
   
   
       19 . The system of  claim 18 , further including a fuel driven burner located upstream of the particulate filter. 
   
   
       20 . The system of  claim 19  wherein the fuel driven burner is configured to heat the exhaust gas supplied to the particulate filter such that the particulate filter is heated to the intermediate temperature, maintained at the intermediate temperature, and heated to the regeneration temperature, in response to one or more commands from the control system.