System and method for detecting diesel particulate filter conditions based on thermal response thereof

Abstract

Systems and methods to determine conditions of a diesel particulate filter (DPF) based on correlation between predicted and actual thermal data of the fluid exiting a DPF are provided. Soot loading, ash loading, and/or DPF damage may be detected, and DPF operational models may be calibrated in accordance with such systems and methods. Further, initiation of regeneration may also be effected in accordance with such systems and methods.

1 . A method of detecting conditions of a diesel particulate filter (DPF) used in the exhaust system of a diesel engine, the exhaust system including a heat addition device for initiating a regeneration of the DPF, the heat addition device being controlled by a controller programmed with a regeneration algorithm that determines when to initiate the regeneration process, at least one sensor is coupled to the controller for monitoring input characteristics of exhaust entering the DPF including at least one temperature sensor for monitoring an input temperature of the exhaust entering the DPF and at least one sensor for monitoring an output temperature of the exhaust exiting the DPF, the method comprising the steps of:
 determining estimated thermal exit temperature data of the exhaust exiting the DPF based at least in part on the input characteristics of the exhaust entering the DPF; 
 measuring the output temperature data of the exhaust exiting the DPF to determine actual thermal exit temperature data of exhaust exiting the DPF; 
 comparing the estimated thermal exit temperature data to the actual thermal exit temperature data to determine a difference therebetween; and 
 determining the condition of the DPF by analyzing the difference. 
 
     
     
         2 . The method of  claim 1 , further comprising the step of:
 initiating a regeneration of the DPF; and   wherein the step of analyzing comprises the steps of:
 integrating the difference between the estimated thermal exit temperature data and the actual thermal exit temperature data to determine an amount of soot burned during regeneration; and 
 adjusting an initiation of a subsequent regeneration based on the amount of soot burned during the regeneration relative to a predicted amount of soot burned during the regeneration. 
   
     
     
         3 . The method of  claim 2 , wherein the step of adjusting comprises the step of retarding initiation of the subsequent regeneration when the amount of soot burned is less than a predetermined amount and the step of adjusting comprises the step of accelerating initiation of a subsequent regeneration when the amount of soot burned is greater than a predetermined amount. 
     
     
         4 . The method of  claim 2 , wherein the controller is programmed with a soot loading algorithm configured to determine when to initiate regeneration of the DPF by predicting soot loading of the DPF, and wherein the step of adjusting comprises adjusting the soot loading algorithm to retard the soot loading algorithm to determine slower soot loading and thus retard initiation of the next regeneration when the amount of soot burned is less than a predetermined amount and comprises adjusting the soot loading algorithm to accelerate the soot loading algorithm to determine quicker soot loading and thus accelerate initiation of the next regeneration when the amount of soot burned is greater than a predetermined amount. 
     
     
         5 . The method of  claim 1 , further comprising:
 initiating an enhanced regeneration of the DPF to establish a baseline clean condition of the DPF;   after completion of the enhanced regeneration, applying a heat pulse to the DPF;   determining the estimated thermal exit temperature data of the exhaust exiting the DPF based at least in part on the input temperature of the exhaust entering the DPF during the heat pulse;   measuring the output temperature of the exhaust exiting the DPF during the heat pulse to determine actual thermal exit temperature data of the exhaust exiting the DPF during the heat pulse;   comparing the estimated thermal exit temperature data during the heat pulse to the actual thermal exit temperature data during the heat pulse to determine a calibration difference therebetween; and   calibrating the step of determining estimated thermal exit temperature data of exhaust exiting the DPF during a subsequent process based on the calibration difference.   
     
     
         6 . The method of  claim 5 , wherein the step of calibrating includes calibrating a thermal model of the DPF used during the step of determining the estimated thermal exit temperature profile of the exhaust exiting the DPF based on the calibration difference. 
     
     
         7 . The method of  claim 1 , wherein the step of analyzing the difference to determine the condition of the DPF comprises the step of providing an indication that maintenance of the DPF is required when the difference indicates that the actual thermal exit temperature data is different than the estimated thermal exit temperature data by a predetermined amount. 
     
     
         8 . The method of  claim 1 , wherein the step of analyzing the difference to determine the condition of the DPF comprises the step of providing an indication that damage to the DPF has occurred when the difference indicates that at least a portion of the actual thermal exit temperature data has a rate of change that is different than a rate of change of a corresponding portion of the estimated thermal exit temperature data by a predetermined amount. 
     
     
         9 . The method of  claim 1 , further comprising the steps of:
 applying a heat pulse to the DPF;   determining the estimated thermal exit temperature data of the exhaust exiting the DPF during the heat pulse;   measuring the output temperature of the exhaust exiting the DPF during the heat pulse to determine actual thermal exit temperature data of the DPF as a result of the heat pulse;   comparing the estimated thermal exit temperature data during the heat pulse to the actual thermal exit temperature data during the heat pulse to determine a calibration difference therebetween; and   calibrating the step of determining the estimated thermal exit temperature profile of the exhaust exiting the DPF during a subsequent regeneration based on the calibration difference.   
     
     
         10 . The method of  claim 9 , wherein the step of calibrating includes calibrating a thermal model of the DPF used during the step of determining the estimated thermal exit temperature data of the exhaust exiting the DPF based on the calibration difference. 
     
     
         11 . The method of  claim 9 , wherein the steps of applying a heat pulse to the DPF and calibrating occur as a new hardware self-calibration prior to soot loading of the DPF. 
     
     
         12 . The method of  claim 1 , further comprising the steps of:
 applying a different heat pulse to the DPF;   determining the estimated thermal exit temperature data of the exhaust exiting DPF as a result of the heat pulse;   measuring the output temperature of the exhaust exiting DPF as a result of the heat pulse to determine the actual thermal exit temperature data of the exhaust exiting DPF as a result of the heat pulse;   comparing the estimated thermal exit temperature data during the heat pulse to the actual thermal exit temperature data during the heat pulse to determine a regeneration initiation difference therebetween; and   initiating a regeneration when the regeneration initiation difference is greater than a predetermined value.   
     
     
         13 . A diesel particulate filter (DPF) system for removing particulates from diesel engine exhaust, comprising:
 a diesel particulate filter (DPF) having an inlet and an outlet;   a heat addition device;   a DPF input temperature sensor positioned to sense temperature of fluid entering the DPF at the DPF inlet;   a DPF output temperature sensor positioned to sense temperature of fluid exiting the DPF at the DPF outlet;   a controller configured to control the heat addition device to initiate regeneration of the DPF based on a regeneration algorithm; and   wherein the controller is configured to determine estimated thermal data of the DPF based at least in part on the input temperature of the fluid entering the DPF, to measure the output temperature of the fluid exiting the DPF to determine actual thermal data of the DPF, to compare the estimated thermal data to the actual thermal data to determine a difference therebetween, and to analyze the difference to determine the condition of the DPF.   
     
     
         14 . The system of  claim 13 , wherein the controller is configured to integrate the difference to determine an amount of soot burned during regeneration, and adjusts when a subsequent regeneration is initiated based on the amount. 
     
     
         15 . The system of  claim 14 , wherein the controller is configured to retard determination of a initiation of a subsequent regeneration when the amount of soot burned is less than a predetermined amount and wherein the controller is configured to accelerate determination of an initiation of the subsequent regeneration when the amount of soot burned is greater than a predetermined amount. 
     
     
         16 . The system of  claim 13 , wherein the controller is further configured to initiate an enhanced regeneration of the DPF to establish a baseline clean condition of the DPF, and after completion of the enhanced regeneration, to apply a heat pulse to the DPF, to determine the estimated thermal data of the fluid exiting the DPF as a result of the heat pulse, to measure the output temperature of the fluid exiting the DPF as a result of the heat pulse to determine the actual thermal data of fluid exiting the DPF, to compare the estimated thermal data to the actual thermal data to determine a calibration difference therebetween, and to calibrate the controller's configuration to determine the estimated thermal data of the fluid exiting the DPF during a subsequent process based on the calibration difference. 
     
     
         17 . The system of  claim 13 , wherein the controller is configured to provide an indication that maintenance of the DPF is required when the difference indicates that the actual thermal data is different than the estimated thermal data by a predetermined amount. 
     
     
         18 . The system of  claim 13 , wherein the controller is configured to provide an indication that the DPF is damaged when the difference indicates that at least a portion of the actual thermal exit temperature profile has a rate of change that is different than a rate of change of a corresponding portion of the estimated thermal exit temperature data by a predetermined amount. 
     
     
         19 . The system of  claim 13 , wherein the controller is configured to apply a heat pulse to the DPF prior to determining the estimated thermal data of the DPF, to determine the estimated thermal data of the DPF based at least in part on the input temperature of the DPF during the heat pulse, to measure the output temperature of the DPF during the heat pulse to determine actual thermal data of the DPF during the heat pulse, to compare the estimated thermal data during the heat pulse to the actual thermal data during the heat pulse to determine a calibration difference therebetween, and to calibrate its configuration to determine the estimated thermal data of the DPF based at least in part on the input temperature of the DPF during the subsequent regeneration based on the calibration difference. 
     
     
         20 . A method of detecting conditions of a diesel particulate filter (DPF), comprising the steps of:
 initiating a heat pulse, determining an estimated thermal data of fluid exiting the DPF based on the temperature of fluid entering the DPF;   measuring the output temperature of the fluid exiting the DPF to obtain actual thermal data of the fluid exiting the DPF as a result of the heat pulse;   comparing the estimated thermal data to the actual thermal data to determine a difference therebetween;   calibrating a thermal model of the DPF based on the difference.   
     
     
         21 . The method of  claim 20 , wherein all steps are performed for at least a first time as a new hardware self-calibration. 
     
     
         22 . The method of  claim 20 , further comprising the step of initiating an enhanced regeneration to establish a clean baseline of the DPF and wherein all steps are performed after the step of initiating the enhanced regeneration, and the step of calibrating updates the thermal model to compensate for changes in the DPF due to particulate loading of the DPF.