| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique in an engine exhaust emission control system including a NOx catalyst for both reducing an adding amount of a reducing agent concerning sulfur poisoning recovery control, and improving the state of exhaust emission when the sulfur poisoning recovery control is not performed. <P>SOLUTION: The engine exhaust emission control system includes: a first turbo charger 10 having a first turbine 102 provided in an first exhaust branch passage 91; a second turbo charger 20 having a second turbine 202 provided in a second exhaust branch passage 92; and an exhaust bypass 94 connecting the second exhaust branch passage 92 downstream of the second turbine 202 to an exhaust passage 9 downstream of a NOx catalyst 11. When the sulfur poisoning recovery control is not performed, a three-way valve 95 is controlled to a first position, and when the sulfur poisoning recovery control is performed, the three-way valve 95 is controlled to a second position. <P>COPYRIGHT: (C)2010,JPO&INPIT |
