| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an engine equipped with an EGR passage and an exhaust post-processing device wherein the occurrence of surging is prevented when changing an excess air ratio to a lean state from a state in which the excess air ratio is controlled to the rich side for recovery or the like of the exhaust post-processing device. <P>SOLUTION: The control device is equipped with a turbocharger 21 driven by exhaust energy of an engine 1, an exhaust post-processing device of at least either of a NOx trap catalyst 29 or a DPF 28, an EGR passage 4 through which an exhaust passage 2 communicates to an intake passage 3 of the engine 1, an EGR valve 6 for adjusting the flow passage cross section of the EGR passage 4 and an excess air ratio control means 31 for controlling the excess air ratio in accordance with an operating condition so as to bring the excess air ratio into at least a rich state or a lean state. When returning the excess air ratio to the lean state from the state in which the excess air ratio is controlled to the rich side, the EGR valve 6 is closed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
