| 摘要 |
A three-way catalytic converter 42 and a combined catalytic-hydrocarbon adsorbent 43 are arranged in an exhaust manifold 32 of an engine 11. The three-way catalytic converter 42 and the combined catalytic-hydrocarbon adsorbent 43 are arranged adjacent to each other in series from an upstream. A pulsing stream of the exhaust gas is kept strong at the point where combined catalytic-hydrocarbon adsorbents 42 are arranged. Thus, hydrocarbons desorbed from the combined catalytic-hydrocarbon adsorbents 42 are strongly affected by an action of a pulsing stream of the exhaust gas, and hydrocarbons desorbed from the combined catalytic-hydrocarbon adsorbent 43 flow backward in the direction of the three-way catalytic converter 42. Consequently, hydrocarbons desorbed from the combined catalytic-hydrocarbon adsorbent 43 are given a chance to contact with the three-way catalytic converter 42 again, and are oxidized with the three-way catalytic converter 42.
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