| 摘要 |
A catalyst unit (16), in which a quantity of a relatively expensive material such as platinum is replaced by a greater quantity of a relatively inexpensive material such as palladium. Thus, material cost saved by "tailoring" a pack is used to pay for a large quantity of a cheaper material. Although the cheaper material is generally less intrinsically efficient than the expensive material, a sufficient additional amount of the cheaper material can be used to more than compensate for this lack of efficiency. Thus, a catalytic pack of high catalytic efficiency, low material cost, low metal loss and long run duration can be produced. |
