Patent ID: 7296401

Claim:
A device for purifying the exhaust gas of an internal combustion engine comprising: a particulate filter arranged in the exhaust system, wherein said particulate filter is a wall-flow particulate filter comprising a partition wall having pores, said partition wall carrying a catalyst for absorbing and reducing NO x on the exhaust gas upstream side surface thereof, said catalyst absorbing NO x when the air-fuel ratio in the surrounding atmosphere thereof is lean and releasing the absorbed NO x when said air-fuel ratio is stoichiometric or rich; a catalytic apparatus for purifying NO x arranged in the exhaust system upstream of said particulate filter, which catalytic apparatus carries a catalyst absorbing NO x when the air-fuel ratio in the surrounding atmosphere thereof is lean and releasing the absorbed NO x when said air-fuel ratio is stoichiometric or rich; and control means for making the air-fuel ratio in said catalytic apparatus rich to release NO x from said catalyst of said catalytic apparatus to purify the released NO x by reduction, and making the air-fuel ratio in the particulate filter rich to release NO x from said catalyst of said particulate filter to purify the released NO x by reduction so that said catalyst of said particulate filter also releases active-oxygen to oxidize and remove the particulates trapped on said particulate filter without producing luminous flame.