EXHAUST GAS PURIFICATION UNIT

• Main Authors: FUJITA NAOTO, TOJO TAKUMI, HOSHINO SHO, ITO MINORU, CHINZEI ISAO, SHIRAKAWA SHOGO
• Format: Patent
• Language: English; Japanese
• Published: 10.03.2022
• 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

To provide an exhaust gas purification unit showing high NOx purification rate even after use under a high temperature condition.SOLUTION: An exhaust gas purifying unit comprises a substrate having an upstream end and a downstream end, whose length between the upstream end and the downstream end is Ls, a first catalyst layer comprising Pd particles formed in contact with the substrate in a first region between the upstream end and a first position separating a first distance La toward the downstream end from the upstream end, a second catalytic layer comprising Rh particles formed in contact with the substrate in a second region between the downstream end and a second position separating a second distance Lb from the downstream end to the upstream end, and a third catalytic layer comprising Rh particles formed in contact with at least the first catalyst layer in a third region between the upstream end and a third position separating a third distance Lc from the upstream end to a third position separating a third distance Lc toward to the downstream end. An average of a particle size distribution of the Rh particles is 1.0 to 2.0 nm and a standard deviation is 0.8 nm or smaller.SELECTED DRAWING: Figure 1 【課題】高温条件下での使用後も高いＮＯｘ浄化率を示す排ガス浄化装置を提供する。【解決手段】排ガス浄化装置は、上流端及び下流端を有し、前記上流端と前記下流端の間の長さがＬｓである基材と、前記上流端と前記上流端から前記下流端に向かって第一距離Ｌａを隔てた第一位置との間の第一領域において前記基材に接して形成された、Ｐｄ粒子を含む第一触媒層と、前記下流端と前記下流端から前記上流端に向かって第二距離Ｌｂを隔てた第二位置との間の第二領域において前記基材に接して形成された、Ｒｈ粒子を含む第二触媒層と、前記上流端と前記上流端から前記下流端に向かって第三距離Ｌｃを隔てた第三位置との間の第三領域において少なくとも前記第一触媒層に接して形成された、Ｒｈ粒子を含む第三触媒層と、を備える。前記Ｒｈ粒子の粒径分布の平均は１．０～２．０ｎｍであり且つ標準偏差は０．８ｎｍ以下である。【選択図】図１