To improve deterioration in fuel consumption for NOX reduction in exhaust gas, in an exhaust emission control device for an internal combustion engine provided with a NOX reduction catalyst device carrying a base metal catalyst and having low NOX reduction performance.
An exhaust emission control device for an internal combustion engine includes: a first NOX reduction catalyst device 40 carrying a base metal catalyst disposed at an exhaust passage 30; a second NOX reduction catalyst device 50 disposed at the exhaust passage at a downstream side of the first NOX reduction catalyst device and having ammonia storage capability; and a first NOX sensor 80 disposed at the exhaust passage at a downstream side of the second NOX reduction catalyst device. After a combustion air-fuel ratio of the internal combustion engine is made richer than a theoretical air-fuel ratio, the combustion air-fuel ratio of the internal combustion engine is made leaner than the theoretical air-fuel ratio. When the combustion air-fuel ratio of the internal combustion engine is made leaner than the theoretical air-fuel ratio, if NOX is detected by the first NOX sensor, the combustion air-fuel ratio of the internal combustion engine is made richer than the theoretical air-fuel ratio.
MORIKAWA AKIRA
TOYOTA CENTRAL RES & DEV
| JPH09133032A | 1997-05-20 | |||
| JP2008528281A | 2008-07-31 | |||
| JP2010203267A | 2010-09-16 | |||
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| WO2011061820A1 | 2011-05-26 |
Jun Tsuruta
Tetsuro Shimada
Shinji Mitsuhashi
Koichi Ito
Tatsuki Sone