Method of diesel particulate filter (dpf) to calculate actual soot load and ash load of the filter

Abstract

A method to operate an internal combustion engine with a diesel particulate filter to extend the life of the diesel particulate filter by initiating active regeneration of the diesel particulate filter when the soot load of the filter exceeds a predetermined actual soot load value.

1 . A method to operate an electronically controlled compression ignition engine equipped with an Electronic Control Unit (ECU) and having an exhaust system including an exhaust after treatment system including a Diesel Particulate Filter (DPF); said method comprising:
 determining a soot loading portion of soot emissions in said engine exhaust;   determining a soot unloading portion of soot emission in said DPF;   determining whether a difference between said soot loading portion and said soot unloading portion exceeds a predetermined actual soot load value; and   initiating active regeneration of said DPF.   
     
     
         2 . The method of  claim 1 , wherein said soot loading portion is determined according to the formula
     Y _Loading= ab  (X m   +cX   n )   
       Wherein
 Y_Loading=the soot loading portion; 
 a=f a,  which represents a correction factor; 
 b=f b  which represents Lambda, air mass flow; 
 c=f c  which represents a correction factor; and 
 X=f x  which represents engine smoke numbers out. 
 
     
     
         3 . The method of  claim 1 , wherein said soot unloading portion is determined according to the formula
     Y _Unloading= abc X   n      
       Wherein
 Y_Unloading=the soot unloading portion; 
 a=f a,  which represents specific unloading factor; 
 b=f b  which represents Lambda, DPF temperatures; 
 c=f c  which represents NO, NO 2 ; and 
 X=f x  which represents actual soot load. 
 
     
     
         4 . The method of  claim 1 , wherein actual soot load of the DPF is determined according to the formula
     Y _Soot_Load_Actual= Y _Loading− Y _Unloading
   
     
     
         5 . The method of  claim 1 , wherein a higher than normal soot and ash load in said DPF is determined according to the formula
     Y _ΔP —   DPF=ab/cd   n  
   Wherein   a=f a,  which represents DPF exhaust gas flow pressure in, out offset;   b=f b  which represents ambient pressure, DPF pressure in, out;   c=f c  which represents DPF temperatures;   d=f d  which represents exhaust mass flow; and   P=exhaust gas flow pressure.   
     
     
         6 . The method of  claim 1 , wherein said soot load, soot loading portion, soot unloading portion are values in tables in memory in said ECU. 
     
     
         7 . A diesel fuel engine exhaust after treatment system including a Diesel Particulate Filter (DPF) comprising: a controller configured to determine a soot loading portion of soot emissions in said engine exhaust; determine a soot unloading portion of soot emission in said DPF; determine whether a difference between said soot loading portion and said soot unloading portion exceeds a predetermined actual soot load value; and initiate active regeneration of said DPF. 
     
     
         8 . The diesel fuel engine exhaust aftertreatment system of  claim 7 , wherein said soot loading portion is determined according to the formula
     Y _Loading= ab  ( X   m   +cX   n )   
       Wherein
 Y_Loading=the soot loading portion; 
 a=f a,  which represents a correction factor; 
 b=f b  which represents Lambda, air mass flow; 
 c=f c  which represents a correction factor; and 
 X=f x  which represents engine smoke numbers out. 
 
     
     
         9 . The diesel fuel engine exhaust aftertreatment system of  claim 7  wherein said soot unloading portion is determined according to the formula
     Y _Unloading= abc X   n    
 Wherein 
 Y_Unloading=the soot unloading portion;
 a=f a,  which represents specific unloading factor; 
 b=f b  which represents Lambda, DPF temperatures; 
 c=f c  which represents NO, NO 2 ; and 
 X=f x  which represents actual soot load. 
 
 
     
     
         10 . The diesel fuel engine exhaust aftertreatment system of  claim 7 , wherein actual soot load of the DPF is determined according to the formula
     Y _Soot_Load_Actual= Y _Loading− Y _Unloading.
   
     
     
         11 . The diesel fuel engine exhaust aftertreatment system of  claim 7 , wherein a higher than normal soot and ash load in said DPF is determined according to the formula
   Y_ΔP_DPF= ab/cd   n  
   Wherein   a=f a,  which represents DPF exhaust gas flow pressure in, out offset;   b=f b  which represents ambient pressure, DPF pressure in, out;   c=f c  which represents DPF temperatures;   d=f d  which represents exhaust mass flow; and   P=exhaust gas flow pressure.   
     
     
         12 . The diesel fuel engine exhaust aftertreatment system of  claim 7 , wherein said soot load, soot loading portion, soot unloading portion are values in tables in memory in said controller.