Patent ID: 6851258

Claim:
A regeneration device for a filter which traps particulate matter contained in the exhaust gas of an internal combustion engine, the particulate matter burning at a predetermined temperature, the device comprising: an exhaust gas temperature adjustment mechanism which regulates a temperature of the exhaust gas; an exhaust gas oxygen concentration adjustment mechanism which regulates an oxygen concentration of the exhaust gas; a sensor which detects a temperature of the filter; and a controller functioning to: control the exhaust gas temperature adjustment mechanism in a first phase such that the exhaust gas temperature is raised until the temperature of the filter rises to a predetermined temperature; control the exhaust gas oxygen concentration adjustment mechanism in a second phase following the first phase to cause the oxygen concentration of the exhaust gas to be held at a first target concentration while controlling the exhaust gas temperature adjustment mechanism to cause the temperature of the filter to be maintained at the predetermined temperature; and control the exhaust gas oxygen concentration adjustment mechanism in a third phase following the second phase to cause the oxygen concentration of the exhaust gas to be held at a second target concentration which is higher than the first target concentration while controlling the exhaust gas temperature adjustment mechanism to cause the temperature of the filter to be maintained at the predetermined temperature.