Patent ID: 7610753

Claim:
An exhaust gas purification apparatus for an internal combustion engine, comprising: a filter disposed in an exhaust passage and arranged in fluid communication with the internal combustion engine, that traps particulate matter in exhaust gas in the exhaust passage; a three-way catalyst, carried on the filter; and a control unit, wherein the exhaust passage is shaped such that all of the exhaust gas always passes through the filter and the three-way catalyst before exiting from the exhaust passage, and wherein the control unit is configured to simultaneously perform regeneration of the filter to remove accumulated particulate matter and to purify the three-way catalyst, by controlling at least one engine operating parameter related to combustion of the internal combustion engine, such that exhaust gas flowing out of the internal combustion engine has a lean air-fuel ratio and the exhaust gas flowing into the filter has a lean air-fuel ratio and the exhaust gas flowing out of the filter has a substantially stoichiometric air-fuel ratio.