| 摘要 |
PROBLEM TO BE SOLVED: To perform full exhaust emission control with small electric power even before a main catalyst part is activated. SOLUTION: When a controller 20 judges that a main catalyst part 11 is before being activated on the basis of an exhaust gas temperature, a selector switch 18 is turned to ON to have a sub-catalyst part 13 energized, and a selector valve 19 is operated to close a second inflow passage R2. Thereby, the sub-catalyst part 13 itself becomes a heating element for getting a high temperature to reach a catalyst activation temperature, and exhaust gas flows only into a first inflow passage R1. Consequently, as in the exhaust gas, its injurious ingredients are fully removed by having the gas passed through the activated sub-catalyst part 13, there is no problem even if the main catalyst part 11 is not activated. As a cross section of the sub-catalyst part 13 is smaller than that of the main catalyst part 11, electric power required for heating and activating the sub-catalyst part 13 may be small. |
