| 摘要 |
PROBLEM TO BE SOLVED: To sufficiently reduce NOx without using heater by providing an inflow prevention means preventing exhaust gas from directly coming in a reforming catalyst, and providing a feed means feeding fuel to a NOx catalyst by way of the reforming catalyst in a device having both the NOx catalyst and the reforming catalyst disposed for an exhaust system. SOLUTION: A NOx catalyst 2 is disposed at the exhaust downstream side of an expanded tube part for the exhaust passage of a diesel engine, and a reforming catalyst 3 is disposed at the exhaust downstream of a through hole 2a for the catalyst 2. A plate member 4 is disposed to the end face at the exhaust downstream, the through hole 2a is thereby closed, and exhaust gas is so designed as not to pass through the through hole 2a. And a feed pipe 5 is connected with the plate member 4 in order to feed light oil and air as hydro carbon fuel to the reforming catalyst 3. The feed pipe 5 is branched into two at the external part of the exhaust passage 1, one of them is connected with a fuel pump by way of a control valve 5a controlling the feed quantity of light oil, and the other one is connected with an air pump by way of a control valve 5b controlling the feed quantity of air. |
