| 摘要 |
PURPOSE:To provide a high purifying rate of exhaust gas even in the case that a nature of exhaust gas is frequently changed. CONSTITUTION:The first/second catalysts 3, 4 are arranged in series so as to place the former in the downstream and the latter in the upstream, in a flow direction of exhaust gas. An activation temperature range of the first catalyst 3 is wide in a low temperature side from that of the second catalyst 4, and on the other hand, an activation temperature range of the second catalyst 11 is wide in a high temperature side from that of the first catalyst 3, further with mutual activation temperature range partly lapped of both the catalysts 3, 4. |
