| 摘要 |
PROBLEM TO BE SOLVED: To provide a warming up control device for catalyst capable of warming up the catalyst at an early stage while suitably suppressing deterioration of exhaust emission in a downstream of the catalyst. SOLUTION: Ignition timing delay operation is performed before the temperature of the catalyst reaches a predetermined temperature T1 at which the catalyst starts purification of exhaust gas. Consequently, temperature of exhaust gas is raised and warming up control of the catalyst is performed by heat of exhaust gas. When the catalyst temperature gets T1 or higher, forced vibration operation of air fuel ratio between a lean state and a rich state as compared to theoretical air fuel ratio is performed. Consequently, warming up control of the catalyst is performed by oxidation reaction heat of oxygen produced by lean combustion and oxygen produced by rich combustion. COPYRIGHT: (C)2006,JPO&NCIPI
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