Patent ID: 7614218

Claim:
An exhaust emission purifying apparatus of an internal combustion engine, comprising: a particulate filter disposed in an exhaust passage of the engine for collecting particulate matters in the exhaust gas of the engine; a reduction catalyst that accelerates the reductive purification of nitrogen oxides in the exhaust gas, the reduction catalyst being disposed downstream of the particulate filter in the exhaust passage; a bypass passage arranged to diverge from the exhaust passage downstream of the particulate filter thereby extending to bypass the reduction catalyst and to merge with the exhaust passage downstream of the reduction catalyst; a flow path switching valve disposed for switching a flow path that the exhaust gas having passed through the particulate filter flows between the exhaust passage and the bypass passage; a temperature sensor disposed upstream of the reduction catalyst in the exhaust passage for detecting a temperature of the exhaust gas having passed through the particulate filter; a control unit configured to control the switching valve in association with the temperature of the exhaust gas detected by the temperature sensor; and a filter regenerator configured to forcibly burn particulate matters collected by the particulate filter to regenerate the particulate filter, wherein, in a regenerating period of the particulate filter when the particulate filter is regenerated by the filter regenerator, the control unit switches the flow path for the exhaust gas having passed through the particulate filter to the bypass passage, and wherein, after the regeneration period of the particulate filter is completed, the control unit switches the flow path for the exhaust gas to the exhaust passage when the temperature of the exhaust gas detected by the temperature sensor falls and reaches a predetermined temperature.