Exhaust Emission Control Device

Abstract

An oxidation catalyst arranged frontward of a catalytic regenerative particulate filter is prevented from being clogged. Disclosed is an exhaust emission control device in which a catalytic regenerative particulate filter 4 is incorporated in an exhaust pipe 3 and has a flow-through type oxidation catalyst arranged frontward of the filter, fuel being added to exhaust gas 2 upstream of the particulate filter 4 , heat generated by oxidation reaction of the added fuel on the frontward oxidation catalyst being used for combustion of captured particulates in the backward particulate filter to forcedly regenerate the particulate filter. Arranged frontward of the catalytic regenerative particulate filter 4 is the flow-through type oxidation catalyst 12 carried by a honeycomb-structured metallic carrier.

1 . An exhaust emission control device wherein a catalyst regenerative particulate filter is incorporated in an exhaust pipe and has a flow-through type oxidation catalyst arranged frontward of the filter, fuel being added to exhaust gas upstream of the particulate filter, heat generated by oxidation reaction of the added fuel on the frontward oxidation catalyst being used for combustion of captured particulates in the rearward particulate filter to thereby forcedly regenerate the particulate filter, said exhaust emission control device comprising the frontward oxidation catalyst carried by a metallic carrier. 
     
     
         2 . An exhaust emission control device wherein a catalyst regenerative particulate filter is incorporated in an exhaust pipe and has a flow-through type oxidation catalyst arranged frontward of the filter, fuel being added to exhaust gas upstream of the particulate filter, heat generated by oxidation reaction of the added fuel on the frontward oxidation catalyst being used for combustion of captured particulates in the rearward particulate filter to thereby forcedly regenerate the particulate filter, said exhaust emission control device comprising the frontward oxidation catalyst divided into front and rear oxidation catalysts, the divided front and rear oxidation catalysts being carried by metallic and ceramic carriers, respectively.