EXHAUST GAS PURIFICATION CATALYST

• Main Authors: NAGANUMA YUKI, IMOTO RUI
• Format: Patent
• Language: English; Japanese
• Published: 21.04.2016
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

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 【課題】複雑な構成を有することなく、触媒の耐久性、使用する触媒金属量及び排気ガスの通路抵抗を維持したまま、触媒の浄化性能を向上させた排気ガス浄化用触媒の提供。【解決手段】第１触媒２-１と、第１触媒２−１と排気ガス３の流れ方向に対して後方に設置された第２触媒２−２と、第１触媒２−１よりも排気ガス３の流れ方向に対して前方に設置されたA/Fセンサ５と、第１触媒２−１と第２触媒２−２の間に設けられた隙間部に設置された酸素センサ４とを備え、第１触媒２−１の第２触媒２−２に対する容積比が0.3〜1.5であり、隙間部の長さが排気ガスの流れ方向に沿って30mm〜300mmであり、第１触媒２−１及び第２触媒２−２はそれぞれ担体と、担体に被覆されたコート層とを含有し、コート層は前記担体の表面上に形成されるパラジウムを含む下層と、下層の上面に形成されるロジウムを含む上層とを有する２層構造の排気ガス浄化用触媒１。【選択図】図１