To appropriately avoid deterioration of emission due to leakage from a bypass selector valve in an exhaust emission control device for an internal combustion engine including a PM filter.
This exhaust emission control device for an engine (200) includes: a NOx storage catalyst (301) arranged in an exhaust system; a PM filter (302) arranged on a downstream side of the NOx storage catalyst and enabled to be forcibly regenerated; a bypass passage (207) divided from an exhaust system at a branch point (208) on an upstream side of the NOx storage catalyst to lead the exhaust to the PM filter, bypassing the NOx storage catalyst; a secondary air supply passage (211) for leading the PM filter regenerating air to a downstream side of the branch point and an upstream side of the NOx storage catalyst; a selector means (210) capable of selecting an exhaust supply route; and a control means for controlling an air-fuel ratio of the exhaust to a rich condition and while for controlling the exhaust to bypass the NOx storage catalyst in execution of forcible regeneration.
| JP2001511493 | [Title of Invention] Gas Purification Device |
| JPH05222918 | DIESEL EXHAUST EMISSION CONTROL DEVICE |
| JPS63268910 | EXHAUST PURIFIER FOR ENGINE |
Koji Yamamoto
Satoshi Nakamura