Exhaust gas-purifying device

Abstract

Provided is a plasma assisted exhaust emission control device with less electric power consumption and with no harmful gas discharged into atmosphere. A filter body 7 is constituted by porous members through which exhaust gas 2 passes for capturing of particulates in the exhaust gas 2 and is provided with rod-like and cylindrical electrodes 9 and 10 so as to generate plasma in the filter body 7 , thereby providing a plasma regenerative particulate filter 11 . The particulate filter 11 is accommodated in a filter casing within an exhaust pipe 3 . Oxidation catalysts 16 and are arranged respectively upstream and downstream of adjacent to the particular filter 11 in the filter casing 12 so as to obtain heat insulation effect to the particulate filter 11.

1 . An exhaust emission control device comprising a filter body constituted by porous members through which exhaust gas passes for capture of particulates entrained in the exhaust gas and electrodes for generating plasma in said filter body, thereby providing a plasma regenerative particulate filter, said particulate filter being incorporated in a filter casing within an exhaust pipe, oxidation catalysts being arranged respectively upstream and downstream of and adjacent to the particulate filter in the filter casing so as to obtain heat insulation effect to the particulate filter.  
   
   
       2 . The exhaust emission control device according to  claim 1 , wherein the plasma regenerative particulate filter is divided into a plurality of smaller units which are arranged in parallel with each other within the filter casing, voltage for electric discharge being separately applicable to the respective smaller units.  
   
   
       3 . The exhaust emission control device according to  claim 1  or  2 , wherein the filter body is constituted by porous members integrally carrying oxidation catalyst.  
   
   
       4 . The exhaust emission control device according to  claim 1  or  2 , wherein the filter body is employed which comprises a number of passages in the form of honeycomb through which exhaust gas passes, inlet and outlet ends of the respective passages being alternately plugged.  
   
   
       5 . The exhaust emission control device according to  claim 3 , wherein the filter body is employed which comprises a number of passages in the form of honeycomb through which exhaust gas passes, inlet and outlet ends of the respective passages being alternately plugged.  
   
   
       6 . The exhaust emission control device according to  claim 4 , wherein the filter body has a rod-like electrode inserted at an axis of the filter body and a cylindrical electrode fitted over an outer periphery of the filter body.  
   
   
       7 . The exhaust emission control device according to  claim 5 , wherein the filter body has a rod-like electrode inserted at an axis of the filter body and a cylindrical electrode fitted over an outer periphery of the filter body.