EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device in which exhaust control performance is prevented from being lowered by improving fuel economy during the recovery of the functions of an NOx storage catalyst and a particulate filter.

SOLUTION: This exhaust emission control device comprises an HC supply means 44 having a particulate filter 38 on the downstream side of an NOx storage catalyst 36 and supplying HC into the exhaust gases flowing into the NOx storage catalyst 36, an exhaust bypass passage 46 having one end connected to an exhaust flow passage on the upstream side more than the HC supply means 44 and the other end connected to the exhaust flow passage between the NOx storage catalyst 36 and the particulate filter 38, and a bypass valve 48 regulating the flow of the exhaust gases flowing in the exhaust bypass flow passage 46. When HC is supplied from the HC supply means 44 into the exhaust gases, the bypass valve 48 is so controlled that the amount of the exhaust gases flowing into the NOx storage catalyst 36 can be reduced more than in the case that the supply of HC is not performed.

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