| 摘要 |
<p>In an exhaust pipe (5), an upstream-side catalyst (6) and a downstream-side catalyst (7) are provided in order from an upstream in an exhaust gas flow direction so as to communicate with each other. An open-flow honeycomb (6c) is provided in a casing (6a) of the upstream-side catalyst (6). In the open-flow honeycomb (6c), a NOx trap catalyst layer (6e) and a low-temperature NOx adsorption catalyst layer (6f) are formed in order from the upstream side in the exhaust gas flow direction. Moreover, in a casing (7a) of the downstream-side catalyst (7), a wall-flow filter (7c) is provided. Moreover, in the wall-flow filter (7c), a NOx reducing catalyst layer (7e) and a PM combustion catalyst layer (7f) are formed in order from the upstream side in the exhaust gas flow direction.</p> |
