EXHAUST EMISSION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To satisfactorily prevent deterioration in a purifying capacity of an exhaust emission catalyst due to a difference in timings of separation of HC and NOx from an adsorbent in an exhaust emission control device of an internal combustion engine.

SOLUTION: This exhaust emission control device is equipped with a main exhaust passage 42 and a first bypass passage 46 that bypasses the main exhaust passage 42. The first bypass passage 46 is provided with the adsorbent 52 having a function for adsorbing HC and NOx components contained in exhaust gas. An underfloor catalyst 56 including a catalyst with an electric heater (EHC) 58 is provided in the main exhaust passage 42 further on the downstream side than a downstream side connecting part 48b of the first bypass passage 46. A second bypass passage 62 is provided for communicating the main exhaust passage 42 at a further downstream side than the underfloor catalyst 56 with the first bypass passage 46 on the further upstream side than the adsorbent 52. A first exhaust switching valve 50 and a second exhaust switching valve 68 are provided to an upstream side connecting part 48a and a main exhaust passage side connecting part 64b, respectively. A pump 66 is provided in the middle of the second bypass passage 62.

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