Exhaust emission control device for internal combustion engine

Abstract

An exhaust emission control device for an internal combustion engine includes a capturing device that is disposed in an exhaust passage of the engine and that captures particulate matter in exhaust gas flowing through the exhaust passage, a sensor that is disposed in the exhaust passage on a downstream side of the capturing device in a flow direction of exhaust gas and that measures an amount of soot in the particulate matter, a control unit for increasing the particulate matter that flows into the capturing device, and a determination device for determining whether the capturing device is at fault based on the amount of soot measured by the sensor after increasing the particulate matter that flows into the capturing device through the control unit.

1 . An exhaust emission control device for an internal combustion engine, comprising:
 a capturing device disposed in an exhaust passage of the engine and configured to capture particulate matter in exhaust gas flowing through the exhaust passage;   a sensor disposed in the exhaust passage on a downstream side of the capturing device in a flow direction of exhaust gas and configured to measure an amount of soot in the particulate matter;   a control means for increasing the particulate matter that flows into the capturing device; and   a determination means for determining whether the capturing device is at fault based on the amount of soot measured by the sensor after increasing the particulate matter that flows into the capturing device through the control means.   
   
   
       2 . The exhaust emission control device according to  claim 1 , wherein the control means includes a first increasing means for increasing a flow of exhaust gas that flows into the capturing device. 
   
   
       3 . The exhaust emission control device according to  claim 2 , further comprising:
 an exhaust gas recirculating passage through which exhaust gas recirculates from the exhaust passage to an intake passage of the engine;   an exhaust gas recirculating valve disposed in the exhaust gas recirculating passage; and   an intake valve disposed in the intake passage, wherein the first increasing means includes an opening degree adjustment means for decreasing a degree of opening of the exhaust gas recirculating valve and for increasing a degree of opening of the intake valve.   
   
   
       4 . The exhaust emission control device according to  claim 1 , wherein the control means includes a second increasing means for increasing smoke in exhaust gas discharged from the engine. 
   
   
       5 . The exhaust emission control device according to  claim 4 , wherein the second increasing means includes an injection adjustment means for adjusting at least one of fuel injection pressure, fuel injection amount, and fuel injection timing of the engine. 
   
   
       6 . The exhaust emission control device according to  claim 1 , further comprising an estimation means for estimating an amount of the particulate matter deposited in the capturing device, wherein the determination means determines whether the capturing device is at fault when the amount of the deposited particulate matter that is estimated by the estimation means is smaller than a predetermined value. 
   
   
       7 . The exhaust emission control device according to  claim 1 , wherein the determination means determines that the capturing device is at fault when the amount of soot measured by the sensor is larger than a threshold value, the device further comprising a threshold value setting means for setting the threshold value using an amount of the particulate matter deposited in the capturing device. 
   
   
       8 . The exhaust emission control device according to  claim 1 , further comprising a determination performing means for performing a following failure determination on the capturing device through the determination means before an elapsed time and/or a travel distance of the vehicle since a previous failure determination of the capturing device through the determination means exceeds a predetermined value.