| 摘要 |
A method and apparatus control an emission of an internal combustion engine. The emission control of the internal combustion engine has a three-way catalyst and a NOx storage-reduction catalyst in an exhaust passage. The emission control reduces NOx stored in the catalyst to recover its NOx storing capability by performing a rich spike control during a lean burn operation. The emission control apparatus has an electronic control unit that limits the execution time of the rich spike control and, after the elapse of the limited execution time, performs a stoichiometric burn operation. The emission control prevents prolongation of the rich spike control and thereby prevents deterioration of HC and CO emissions. By performing the stoichiometric burn operation after the elapse of the limited time of the rich spike control, the emission control apparatus recovers the NOx storing capability while avoiding deterioration of HC and CO emissions.
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