Exhaust-gas converting filter and production process for the same
AssigneesToyota Jidosha Kabushiki Kaisha, Ibiden Co., Ltd.
InventorsMasao Watanabe, Takahiko Ido
Life of this patent
Estimating the term…
Abstract
An outlet-side catalytic layer 22 includes a noble metal in a concentration that is a noble-metal concentration in an inlet-side catalytic layer 20 or more, and the inlet-side catalytic layer 20 contains an NOx storage material in a content that is greater than that in the outlet-side catalytic layer 22 in the inlet-side catalytic layer 20, a pore catalytic layer 21 and the outlet-side catalytic layer 22. PM are converted on the inlet side mainly, and NOx are converted on the outlet side mainly. Therefore, the lowering of the noble metal's activities is suppressed, and additionally it is possible to convert PM and NOx efficiently.
Claims6
An exhaust-gas converting filter comprising:
- a wall-flow structure filer substrate having inlet-side cells being mesh plugged on the exhaust-gas downstream side, outlet-side cells neighboring the inlet-side cells and being mesh plugged on the exhaust-gas upstream side, and porous cellular partition walls demarcating the inlet-side cells and the outlet-side cells and having a large number of pores;
- an inlet-side catalytic layer being formed on a surface on a side of the inlet-side cells of the cellular partition walls;
- an outlet-side catalytic layer being formed on a surface on a side of the outlet-side cells of the cellular partition walls;
- and
- pore catalytic layer being formed on the pores within the cellular partition walls;
- the exhaust-gas converting filter being characterized in that:
- a noble metal is included in the outlet-side catalytic layer in a concentration that is a noble-metal concentration in the inlet-side catalytic layer or more;
- and
- an NOx storage material, which is selected from the group consisting of alkali metals and alkaline-earth metals, is included in the inlet-side catalytic layer, in the pore catalytic layer and in the outlet-side catalytic layer, and a content of the NOx storage material in the inlet-side catalytic layer is greater than that in the outlet-side catalytic layer.
Dependencies are inferred from the claim text.