Particulate matter processing apparatus

Abstract

Aggregation of particulate matter is facilitated. Provision is made for an electrode arranged in an exhaust passage of an internal combustion engine, a power supply connected to the electrode for applying a voltage thereto, an air fuel ratio detection device to detect or estimate an air fuel ratio of an exhaust gas which flows through the exhaust passage, and an electric power control device to make electric power supplied to the electrode from the power supply larger in cases where the air fuel ratio detected or estimated by the air fuel ratio detection device is a rich air fuel ratio than in cases where it is a stoichiometric air fuel ratio or a lean air fuel ratio.

1 . A particulate matter processing apparatus comprising:
 an electrode that is arranged in an exhaust passage of an internal combustion engine;   a power supply that is connected to said electrode and applies a voltage thereto;   an air fuel ratio detection device that detects or estimates an air fuel ratio of an exhaust gas which flows through said exhaust passage; and   an electric power control device that makes electric power supplied to said electrode from said power supply larger in cases where the air fuel ratio detected or estimated by said air fuel ratio detection device is a rich air fuel ratio than in cases where it is a stoichiometric air fuel ratio or a lean air fuel ratio.   
     
     
         2 . The particulate matter processing apparatus as set forth in  claim 1 , wherein said power control device controls said electric power in a such manner that the lower the air fuel ratio detected or estimated by said air fuel ratio detection device, the larger becomes said electric power. 
     
     
         3 . The particulate matter processing apparatus as set forth in  claim 1 , further comprising:
 an exhaust gas amount detection device that detects or estimates an amount of exhaust gas of the internal combustion engine;   wherein said power control device controls said electric power in a such manner that the more the amount of exhaust gas detected or estimated by said exhaust gas amount detection device, the larger becomes said electric power.   
     
     
         4 . The particulate matter processing apparatus as set forth in  claim 1 , further comprising:
 a processing part that is arranged in said exhaust passage with said electrode installed therein;   an insulation part that insulates electricity between said processing part and said exhaust passage;   a ground part that grounds said processing part; and   a current detection device that detects an electric current in said ground part.   a determination device that determines whether a pulse current has been generated in the electric current detected by said detection device; and   a pulse current suppression device that increases a voltage to be applied to said electrode until when a determination is made by said determination device that a pulse current has been generated, and reduces the voltage to be applied to said electrode in cases where a determination has been made by said determination device that a pulse current has been generated, whereby the voltage to be applied to said electrode is adjusted to be lower than a voltage at which a pulse current is generated.