System and method for diesel exhaust fluid demand monitor

Abstract

Systems, apparatuses, and methods include a plurality of diesel exhaust fluid (DEF) dosing systems and a controller. The plurality of DEF dosing systems are in fluid communication with an exhaust gas stream and are structured to provide DEF to the exhaust gas stream. The controller is structured to: determine a commanded amount of DEF dispensed to the exhaust gas stream; determine an actual amount of DEF dispensed to the exhaust gas stream; determine a difference between the commanded amount of DEF and the actual amount of DEF; determine a value of a DEF variable indicative of an amount of DEF not dosed over a predetermined time period; compare the value of the DEF variable to a predetermined threshold; and indicate a fault alert in response to the value of the DEF variable exceeding the predetermined threshold.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a diesel exhaust fluid (DEF) command circuit structured to determine a commanded amount of DEF dispensed to an exhaust gas stream;   a dispensed DEF determination circuit structured to determine an actual amount of DEF dispensed to the exhaust gas stream;   a deficit determination circuit structured to:
 determine a difference between the commanded amount of DEF and the actual amount of DEF; 
 determine a value of a DEF variable indicative of amount of DEF dispensed over a predetermined time period; 
 compare the value of the DEF variable to a predetermined threshold; and 
 indicate a fault alert in response to the value of the DEF variable exceeding the predetermined threshold. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the dispensed DEF determination circuit is structured to receive information indicative of a status of at least one DEF dosing system structured to dispense the commanded amount of DEF to the exhaust gas stream and determine the actual amount of DEF dispensed to the exhaust gas stream based on the information indicative of the status of the at least one DEF dosing system. 
     
     
         3 . The apparatus of  claim 2 , wherein the actual amount of DEF dispensed is determined based on an amount of DEF dosing systems having a dosing status, an amount of time that the DEF dosing systems having the dosing status are dispensing DEF, and a commanded flow rate of DEF. 
     
     
         4 . The apparatus of  claim 1 , further comprising a compensation circuit structured to receive information indicative of a non-dosing status of at least one DEF dosing system of a plurality of DEF dosing systems structured to dispense the commanded amount of DEF to the exhaust gas stream and increase an amount of DEF dispensed by other DEF dosing systems of the plurality of DEF dosing systems in response to receiving the information indicative of the non-dosing status. 
     
     
         5 . The apparatus of  claim 1 , wherein in response to the DEF variable being a non-zero number and the difference being substantially zero, the deficit determination circuit is structured to decrement the DEF variable by a predetermined amount. 
     
     
         6 . The apparatus of  claim 1 , wherein the fault alert is indicative of a cumulative effect of the value of the DEF variable exceeding the predetermined threshold. 
     
     
         7 . A system, comprising:
 a plurality of diesel exhaust fluid (DEF) dosing systems in fluid communication with an exhaust gas stream, the plurality of DEF dosing systems structured to provide DEF to the exhaust gas stream;   a controller structured to:
 determine a commanded amount of DEF dispensed to the exhaust gas stream; 
 determine an actual amount of DEF dispensed to the exhaust gas stream; 
 determine a difference between the commanded amount of DEF and the actual amount of DEF; 
 determine a value of a DEF variable indicative of an amount of DEF not dosed over a predetermined time period; 
 compare the value of the DEF variable to a predetermined threshold; and 
 indicate a fault alert in response to the value of the DEF variable exceeding the predetermined threshold. 
   
     
     
         8 . The system of  claim 7 , wherein the controller is structured to receive information indicative of a status of at least one DEF dosing system of the plurality of DEF dosing systems and determine the actual amount of DEF dispensed to the exhaust gas stream based on the information indicative of the status of the at least one DEF dosing system. 
     
     
         9 . The system of  claim 8 , wherein the actual amount of DEF dispensed is determined based on an amount of DEF dosing systems having a dosing status, an amount of time that the DEF dosing systems having the dosing status are dispensing DEF, and a commanded flow rate of DEF. 
     
     
         10 . The system of  claim 7 , wherein the controller is further structured to receive information indicative of a non-dosing status of at least one DEF dosing system of the plurality of DEF dosing systems and increase an amount of DEF dispensed by other DEF dosing systems of the plurality of DEF dosing systems in response to receiving the information indicative of the non-dosing status. 
     
     
         11 . The system of  claim 7 , wherein the controller is further structured to determine an amount of time that the actual amount of DEF is less than the commanded amount of DEF. 
     
     
         12 . The system of  claim 7 , wherein the DEF variable is a cumulative volume of DEF that has not been dispensed. 
     
     
         13 . The system of  claim 7 , wherein the controller is structured to decrement the DEF variable by a predetermined amount in response to the DEF variable being a non-zero number and the difference being substantially zero. 
     
     
         14 . The system of  claim 7 , wherein the fault alert is indicative of a cumulative effect of the value of the DEF variable exceeding the predetermined threshold. 
     
     
         15 . A method, comprising:
 determining a commanded amount of DEF dispensed to an exhaust gas stream by a plurality of diesel exhaust fluid (DEF) dosing systems in fluid communication with the exhaust gas stream;   determining an actual amount of DEF dispensed to the exhaust gas stream by the plurality of DEF dosing systems;   determining a difference between the commanded amount of DEF and the actual amount of DEF dispensed to the exhaust gas stream by the plurality of DEF dosing systems;   determining a value of a DEF variable indicative of an amount of DEF not dispensed over a predetermined time period;   comparing the value of the DEF variable to a predetermined threshold; and   indicating a fault alert in response to the value of the DEF variable exceeding the predetermined threshold.   
     
     
         16 . The method of  claim 15 , further comprising:
 receiving information indicative of a non-dosing status of at least one DEF dosing system of the plurality of DEF dosing systems; and   increasing an amount of DEF dispensed by other DEF dosing systems of the plurality of DEF dosing systems in response to receiving the information indicative of the non-dosing status.   
     
     
         17 . The method of  claim 15 , further comprising receiving information indicative of a status of at least one DEF dosing system of the plurality of DEF dosing systems and determining the actual amount of DEF dispensed to the exhaust gas stream based on the information indicative of the status of at least one of the DEF dosing systems 
     
     
         18 . The method of  claim 17 , wherein the actual amount of DEF dispensed is determined based on an amount of DEF dosing systems having a dosing status, an amount of time that the DEF dosing systems having the dosing status are dispensing DEF, and a commanded flow rate of DEF. 
     
     
         19 . The method of  claim 15 , further comprising determining an amount of time that the actual amount of DEF is less than the commanded amount of DEF. 
     
     
         20 . The method of  claim 15 , wherein the DEF variable is a cumulative volume of DEF that has not been dispensed.