| 摘要 |
An apparatus for purifying an exhaust gas emitted from a diesel engine (3) includes an oxidizing catalyst (1), and a sulfate-storing-and-reducing catalyst (2). The oxidizing catalyst is disposed on an upstream side in an exhaust system (30) of a diesel engine, and can oxidize at least HC (i.e., hydrocarbons) contained in an exhaust gas emitted from the diesel engine. The sulfate-storing-and-reducing catalyst can not only capture precursors of sulfates (i.e., SO3, SO4<2->, H2SO4, etc.), generated at the oxidizing catalyst, as sulfates, but also can reduce the captured sulfates to SO2, and is disposed on a downstream side with respect to the oxidizing catalyst in the exhaust system. The sulfate-storing-and-reducing catalyst turns the precursors of sulfates into sulfates, stores them, and reduces them to SO2. Thus, the apparatus little emits the precursors of sulfates to the outside, and can inhibit the particulates emission for a long period of time. <IMAGE> |
