Patent ID: 8484952

Claim:
A device for purification of exhaust gas, comprising: an exhaust gas passage connected to an internal combustion engine; a particulate filter which is disposed in the exhaust gas passage, and which traps particulate matters in exhaust gas; an ozone supply member including an ozonizer, connected to the exhaust gas passage and on an upstream side of the particulate filter, and configured to supply ozone to the particulate filter; an NO oxidizing catalyst which is disposed in the exhaust gas passage and on an upstream side of the ozone supply member, and which oxidizes NO in the exhaust gas; means for detecting exhaust gas temperature which performs one of measurement and estimation of a temperature of the exhaust gas passing through the particulate filter; and means for controlling ozone supply which controls the ozone supply member based on the temperature of the exhaust gas detected by the means for detecting exhaust gas temperature, such that ozone is supplied when the temperature of the exhaust gas is within a range between a first predetermined temperature of 50° C. or more and a second predetermined temperature of 300° C. or less; wherein the ozonizer generates ozone from one of air and oxygen serving as a raw material and being taken in as a gas from outside of the exhaust gas passage.