| 摘要 |
PROBLEM TO BE SOLVED: To combine the decrease of moisture in exhaust gas and the presence of a reducing agent such as CO, HC by providing a moisture decomposing means for decomposing moisture, released from a moisture eliminating means, to generate reducing hydrogen. SOLUTION: Until a moisture storage body 46b in a moisture eliminating means 42b in a branch passage 22b is saturated, a photocatalyst 50b is deactivated and does not act. When a moisture eliminating means 42a is energized, on the other hand, moisture stored in a moisture storage body 46a is released, brought into contact with the photocatalyst 50a and decomposed so as to generate reducing hydrogen H and OH. When the moisture absorbing capacity of the moisture storage body 45b is lowered, exhaust gas of an engine 10 flows to a branch passage 22a. At the same time, the moisture storage body 46a starts storing moisture in exhaust gas, and the photocatalyst 50a is deactivated. Exhaust gas passes the photocatalyst 50a without stopping and is fed to a catalytic converter 18. On the other hand, the release of moisture stored in the moisture storage body 46b is started. At the same time, the photocatalyst 50b is activated. |
