Method of estimating soot accumulation amount of exhaust gas purification filter, and computer program product therefor

Abstract

A soot accumulation amount estimation method for an exhaust gas purification filter according to the present invention includes: a first step of burning soot collected in pores of the exhaust gas purification filter to regenerate the filter; a second step of detecting a temperature of exhaust gas flowing into the filter, to judge whether or not the exhaust gas temperature is equal to or lower than a predetermined temperature at which a soot amount flowing into the filter is substantially equal to a soot amount to be burnt in the filter; a third step of adding up a period of time during which the exhaust gas temperature is equal to or lower than the predetermined temperature, when the exhaust gas temperature is equal to or lower than the predetermined temperature; a fourth step of judging whether or not the added up period of time is equal to or longer than a period of time during which a predetermined amount of soot is accumulated in the pores after the first step; and a fifth step of estimating a soot accumulation amount of the filter based on a pressure loss through the filter, when the added up period of time is equal to or longer than the period of time during which the predetermined amount of soot is accumulated.

1 . A soot accumulation amount estimation method for an exhaust gas purification filter, comprising:
 a first step of burning soot collected in pores of the exhaust gas purification filter to regenerate the filter;   a second step of judging whether or not an operation state of an engine is in a burning operation state where a soot amount to be burnt within the filter is larger than a soot amount flowing into the filter;   a third step of adding up a period of time during which the operation state of the engine is in the burning operation state, when the operation state of the engine is judged to be in the burning operation state;   a fourth step of judging whether or not the engine is continuously operated for a predetermined period of time or longer so as to burn out soot within the pores; and   a fifth step of estimating a soot accumulation amount of the filter based on a pressure loss through the filter, when it is judged that the engine is continuously operated in the burning operation state for the predetermined period.   
   
   
       2 . The soot accumulation amount estimation method for an exhaust gas purification filter as claimed in  claim 1 , wherein an exhaust gas purification system having the exhaust gas purification filter possesses data representing a relationship between a pressure loss and a soot accumulation amount of the filter in a state where soot within the pores are burnt out, and
 wherein the fifth step further comprises estimating a soot accumulation amount of the filter, based on a pressure loss through the filter after the burning operation and based on the data.   
   
   
       3 . A computer program product configured to be used for estimating a soot amount accumulated in an exhaust gas purification filter after burning soot collected from exhaust gas by the exhaust purification filter to thereby regenerate the filter comprising;
 a recording medium;   means recorded in the recording medium and configured to judge whether or not an operation state of an engine is in a burning operation state where a soot amount to be burnt within the filter is larger than a soot amount flowing into the filter;   means recorded in the recording medium and configured to add up a period of time during which the operation state of the engine is in the burning operation state;   means recorded in the recording medium and configured to judge whether or not the engine is continuously operated for a predetermined period of time or longer so as to burn out soot within the pores; and   means recorded in the recording medium and configured to estimate a soot accumulation amount of the filter based on a pressure loss through the filter,   when it is judged that the engine is continuously operated in the burning operation state for the predetermined period of time.   
   
   
       4 . The computer program product as claimed in  claim 3 ,
 wherein the recording medium possesses data representing a relationship between a pressure loss and a soot accumulation amount of the filter in a state where soot within the pores are burnt out, and   wherein the estimating means further comprises estimating a soot accumulation amount of the filter, based on a pressure loss through the filter after the burning operation and based on the data.