| 摘要 |
<p>PURPOSE:To improve cost property and durability property by combining a first filter including a fine mesh and in which base metal system catalyst is held, with a second filter which holds noble metal system catalyst, and includes a rougher mesh than that of the first filter. CONSTITUTION:A first filter 3 including a fine mesh and in which base metal system catalyst is held, is combined with a second filter 2 which holds noble metal system catalyst, and includes a rougher mesh than that of the first filter 3. Thus, carbon content mainly in particulates burns efficiently by the filter 2 so as to communicate heat to other filter 3 and assist combustion of the carbon content in the particulates. On the other hand, the particulates are collected completely by the filter 3, while the carbon content in the particulates scattered under non-combustion condition is completely combustion-eliminated. Thus, since combustion of the carbon content is carried out efficiently, durability is improved, while since filter exchanging caused by clogging of ash, is carried out by exchanging only the filter 3 in which base metal system catalyst is held, so as to improve a cost property remarkably.</p> |
