| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust gas purification catalyst having improved purification performance thereof while maintaining the durability of the catalyst, the amount of used catalyst metal, and the passage resistance of exhaust gas without having a complicated configuration.SOLUTION: An exhaust gas purification catalyst 1 comprises a first catalyst 2-1, a second catalyst 2-2 installed rearward of the first catalyst 2-1 with respect to the flow direction of exhaust gas 3, an A/F sensor 5 installed forward of the first catalyst 2-1 with respect to the flow direction of the exhaust gas 3, and an oxygen sensor 4 installed in a space part formed between the first catalyst 2-1 and the second catalyst 2-2. The volume ratio of the first catalyst 2-1 to the second catalyst 2-2 is 0.3-1.5. The length of the space part is 30-300 mm along the flow direction of the exhaust gas. The first catalyst 2-1 and the second catalyst 2-2 respectively include a carrier and a coat layer coated with the carrier. The coat layer has a two-layer structure comprising a palladium-containing lower layer formed on the surface of the carrier and a rhodium-containing upper layer formed on the top surface of the lower layer.SELECTED DRAWING: Figure 1 |
