Patent ID: 7421839

Claim:
An exhaust emission control device comprising: a porous filter body through which exhaust gas passes and which is configured to capture particulates entrained in the gas; a first electric heater that heats the filter body to thereby provide a heat regenerative particulate filter, said heat regenerative particulate filter being accommodated in a filter casing within an exhaust pipe, a second electric heater disposed downstream of the particulate filter; and upstream and downstream oxidation catalysts arranged upstream and downstream, respectively, of and adjacent to the particulate filter in the filter casing so as to provide a thermo-keeping effect to the particulate filter, wherein the exhaust gas arbitrarily bypasses the filter casing, the filter body has a plurality of passages in the form of a honeycomb through which the exhaust gas passes, inlets and outlets of the respective passages being alternately plugged, said first heater is upstream of the particulate filter and downstream of the upstream oxidation catalyst, and the second heater is upstream of the downstream oxidation catalyst.