To provide an exhaust emission control catalyst device for an internal combustion engine with an exhaust emission control catalyst arranged in an exhaust system, having a longer catalyst life and lower catalyst replacing cost by always performing catalyst reaction in the whole exhaust emission control catalyst while suppressing the deterioration of a front end side portion of the exhaust emission control catalyst, in particular.
The exhaust emission control device comprises a catalyst reaction speed estimating means for estimating such a catalyst reaction speed over the total length of the exhaust emission control catalyst from an inlet portion of the exhaust emission control catalyst in which exhaust gas flows to an outlet portion of the exhaust emission control catalyst out of which exhaust gas flows, that the concentration change amount per unit length of an exhaust emission control component to be controlled with catalyst reaction is constant and the concentration of the exhaust emission control component to be controlled at the outlet portion of the exhaust emission control catalyst is zero with catalyst reaction, and a cooling control means for controlling the exhaust emission control catalyst to be cooled so that the catalyst temperature near the inlet portion is suitable to actualize the catalyst reaction speed estimated by the catalyst reaction speed estimating means.
| JPH10259713A | 1998-09-29 |
Jun Tsuruta
Tetsuro Shimada
Shinozaki Masami
Masaya Nishiyama
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