Method and device for recognizing combustion in a particle filter

Abstract

The invention relates to a method for recognizing combustion in a particle filter ( 6 ) provided in the exhaust line of a combustion engine ( 1 ), the filter ( 6 ) having periodic regeneration that is controlled by suitable means, which comprises a step of measuring or estimating parameters representing combustion in said filter ( 6 ) and a step of processing said parameters to diagnose a combustion instance and estimate the strength thereof, and characterized in that said steps are implemented during the entire phase of engine operation ( 1 ), and particularly outside the phases of regeneration controlled by the filter ( 6 ). The invention also relates to a device capable of implementing such a method.

1 . A method for recognizing a combustion in a particle filter installed in an exhaust line of an internal combustion engine and wherein the periodic regeneration of the particle filter commanded by appropriate means; the method comprising a step of measuring or estimating the representative parameters of a combustion in the particle filter and a step of processing these parameters in order to diagnose the occurrence of a combustion in the particle filter and to estimate the intensity of the combustion; said steps of measuring or estimating and processing being implemented during the whole operational phase of the engine, and in particular outside the commanded regeneration phases of the filter. 
     
     
         2 . The method according to  claim 1 , wherein said steps of measuring or estimating and processing are implemented during a predetermined time following shut-down of the combustion engine. 
     
     
         3 . The method according to  claim 1 , wherein said representative parameters are the temperature at the inlet of the particle filter and the temperature at the outlet of the particle filter. 
     
     
         4 . The method according to  claim 3 , wherein a conclusion is made that a combustion of the particles in the particle filter took place if the temperature at the outlet of the particle filter exceeds the temperature at the inlet of the particle filter by a predetermined margin during a predetermined time. 
     
     
         5 . The method according to  claim 3 , characterized in that the temperature gradient inside particle filter is estimated based on the evolution of the temperatures at the inlet and outlet of the filter, and that a conclusion is made that a combustion of the particles in the particle filter took place if the estimated temperature gradient is greater than a predetermined maximum. 
     
     
         6 . The method according to  claim 1 , wherein when a combustion inside the particle filter is detected, the quantity of soot burned during the combustion is evaluated based on the evolution of the temperatures at the inlet and outlet of the particle filter during the combustion and based on the duration of the combustion. 
     
     
         7 . A method for diagnosing the failure of a particle filter installed in the exhaust line of an internal combustion engine employing a method for recognizing a combustion according to  claim 2 , wherein a conclusion is made that the particle filter failed:
 (a) if the value of the temperature at the outlet of the particle filter exceeds the temperature at the inlet of the particle filter by a predetermined value during a predetermined time; or,   (b) if the estimated temperature gradient of the particle filter is greater than a predetermined limit.   
     
     
         8 . (canceled) 
     
     
         9 . The method according to  claim 7 , wherein the combustion engine and particle filter are part of a vehicle; the vehicle comprising an “on board diagnostic” (OBD) module, the method further including a step of entering information of failure of the particle filter in the OBD module if a failure of the particle filter is detected. 
     
     
         10 . The method according to  claim 7 , wherein the combustion engine and particle filter are part of a vehicle; the vehicle comprising an illuminated warning device for warning of an anomaly of the particle filter, said method further including a step of activating said illuminated warning if a failure of the particle filter is detected. 
     
     
         11 . A device comprising a combustion engine equipped with an exhaust line comprising a particle filter, means for commanding the regeneration of said particle filter, means for estimating the representative parameters of a combustion in the particle filter, means for processing these parameters in order to diagnose the occurrence of a combustion and to estimate its intensity, characterized in that said means are employed during the whole operational phase of the engine, and in particular outside the commanded regeneration phases of the particle filter. 
     
     
         12 . The device according to  claim 11 , wherein the estimating means of the parameters are means for estimating or measuring the temperature at the inlet of the filter and a temperature probe at the outlet of the particle filter.