| 摘要 |
<p>PROBLEM TO BE SOLVED: To control toxic component such as NOx and particulate with high efficiency by suppressing the worsening of derivability, fuel consumption, and emission. SOLUTION: A degree of opening of an intake throttle valve 13 and an exhaust circulation control valve 16 is controlled in accordance with high or low temperature of catalyst temperature and exhaust temperature at an inlet of catalyst and an operation condition of a vehicle to control in such a manner that temperature of catalyst of an exhaust emission control device for internal combustion engine is within a specific scope of temperature which is suitable for the action of catalyst at all times. For example, when exhaust temperature becomes higher than catalyst temperature at the time of acceleration of the vehicle, the intake throttle valve 13 is closed slightly and the exhaust circulation control valve 16 is opened slightly to such extent that its operation is not obstructed to raise catalyst temperature speedily. When exhaust temperature drops below catalyst temperature during idling in a condition in which the vehicle is decelerated and stops, the intake throttle valve 13 is closed greatly and the exhaust circulation control valve 16 is opened greatly to keep catalyst temperature and prepare so that high control efficiency is obtained immediately at the time of next acceleration.</p> |
