EXHAUST GAS PURIFICATION DEVICE

• Main Authors: IIZUKA HIDEHIRO, TAKAHASHI KEN, OISHI TOMOJI, MAEKAWA SACHIKO, KAMOTO DAIGORO, KITAHARA YUICHI, ISHIKAWA TAKAO, HANAOKA HIROSHI
• Format: Patent
• Language: English
• Published: 07.01.1997
• Edition: 6
• 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

PURPOSE: To obtain a high NO purification rate using a simple system in an exhaust gas purification device of an internal combustion engine in which combustion is effected in an oxygen excessive atmosphere by disposing a catalyst which is active on NO in a preceding stage on the upstream side of exhaust gas and a catalyst active on NO in a following stage on the downstream side of exhaust gas. CONSTITUTION: In a casing 2, in which exhaust gas 1 flows from the left side to the right side, an NO-reaction type catalyst 3 is disposed on a preceding stage side, while an NO-reaction type catalyst 4 is disposed on a following stage side. And when a NOx-occlusion type catalyst is used, the catalyst 3 is disposed in the preceding stage and a NOx-occlusion type catalyst 5 is disposed in the following stage. And a catalyst to be disposed in the preceding stage is prepared by adding any one selected from among as Zr, Zn, Mg and Ca and a noble metal to alumina, and a catalyst to be disposed in the following stage is a catalyst prepared by adding any one selected from among Mg, Ce and La and a noble metal to alumina, a catalyst in which a noble metal is added to alumina, or a catalyst comprising alkaline earth metal or one of Bi and Nb, rare earth element and a noble metal and alumina.