| 摘要 |
<p>PROBLEM TO BE SOLVED: To simplify the structure of an exhaust emission control device for separating and discharging SOX by making exhaust gas reversely flow into a storage reducing type NOX catalyst. SOLUTION: An exhaust pipe 9 connected to an engine 1 is connected to a first port of an exhaust switching valve 20 having four ports, an exhaust port 10 for discharging exhaust gas to the atmosphere is connected to a second port, an exhaust pipe 11 connected to an inlet 30a of a catalyst converter 30 is connected to a third port, and an exhaust pipe 12 connected to an outlet 30b of the catalyst converter 30 is connected to a fourth port. When the exhaust switching valve 20 is positioned in forward flow, the exhaust pipe 10 and the exhaust pipe 12 are connected to each other as well as connecting the exhaust pipe 9 and the exhaust pipe 11 to each other, and exhaust gas flows from the inlet 30a to the outlet 30b in the catalyst converter 20. When the exhaust switching valve 20 is positioned in reverse flow, the exhaust pipe 10 and the exhaust pipe 11 are connected to each other as well as connecting the exhaust pipe 9 and the exhaust pipe 12 to each other, and exhaust gas flows from the outlet 30b to the inlet 30a in the catalyst converter 20.</p> |
