| 摘要 |
<p>PURPOSE:To provide an exhaust emission control device of engine capable of maintaining purification efficiency at high level as a whole for long period as far as possible. CONSTITUTION:An exhaust emission control device for engine is provided with a pre-catalyst 5, a first path 3 in which main catalysts 6 are mounted in order, an exhaust path 2 with a second path 4 which is installed in the first path 3 so that it bypasses the pre-catalyst 5, and stop valves 7 and 8 to supply and regulate exhaust emission to the first and second paths 3 and 4. When a control unit U judges with a water temperature sensor 11 that an engine is in cool condition, it judges the degree of deterioration of the main catalyst 6 with a sensor 12 which detects a travel distance cumulative value. Then, the stop valves 7 and 8 are controlled so that, as the degree of deterioration becomes smaller, a ratio of exhaust emission supply to the first path 3 is more reduced and that to the second path 4 is more increased.</p> |
