Catalyst-carrying filter
AssigneeNGK Insulators, Ltd.
InventorTakashi Mizutani
Life of this patent
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Abstract
A catalyst-carrying filter includes a gas-inflow-side layer and a gas-outflow-side layer, the gas-inflow-side layer including a PM collection layer that has a small average pore size and a PM removal catalyst layer that supports or is coated with an oxidizing catalyst, and the gas-outflow-side layer including a gas purification catalyst layer that supports or is coated with a gas purification catalyst. An amount of oxidizing catalyst supported on the PM collection and PM removal catalyst layer is larger than that of the gas purification catalyst layer by a factor of 1.05 to 10 and an amount of noble metal contained in the PM collection and PM removal catalyst layer is smaller than an amount of noble metal contained in the gas purification catalyst layer.
Claims12
A catalyst-carrying filter comprising a honeycomb-structured base material having a plurality of cells that serve as exhaust gas passages and are partitioned by a partition wall formed of a porous ceramic having a number of pores, the partition wall including a gas-inflow-side layer and a gas-outflow-side layer,
- one open end and another open end of the plurality of cells being alternately plugged by plugging sections;
- the gas-inflow-side layer including a PM collection and PM removal catalyst layer that has an average pore size of 1 to 15 μm so as to collect particulate matter and supports or is coated with an oxidizing catalyst for promoting oxidation of particulate matter contained in exhaust gas;
- and
- the gas-outflow-side layer including a gas purification catalyst layer that supports or is coated with a gas purification catalyst that promotes oxidation of unburned gas,
- wherein an amount of oxidizing catalyst supported on the PM collection and PM removal catalyst layer is larger than that of the gas purification catalyst layer by a factor of 1.05 to 10 and wherein an amount of noble metal contained in the PM collection and PM removal catalyst layer is smaller than an amount of noble metal contained in the gas purification catalyst layer.
Dependencies are inferred from the claim text.