EXHAUST PURIFYING DEVICE FOR INTERNAL COMBUSTION ENGINE

• Main Author: TAYAMA AKIRA
• Format: Patent
• Language: English
• Published: 06.05.1994
• Edition: 5
• Subjects: BLASTING; 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; STEAM ENGINES; WEAPONS

PURPOSE:To achieve adsorption of HC at the time of cold environment and reduction of NOx under lean condition simultaneously. CONSTITUTION:An auxiliary passage 9 is provided in parallel with the main passage 8 of an exhaust passage, and treatment member 10 on which zeolite is metal-ion exchanged is interposed in the auxiliary passage 9 so as to control a flow of exhaust gas toward the main passage 8 and the auxiliary passage 9 by main and auxiliary passage valves 11, 12. When an exhaust temperature is less than a prescribed low temperature just after an engine is started and so on, exhaust gas is led to the auxiliary passage 9 side, and HC in exhaust gas is adsorbed by the treatment member 10 serving an HC as adsorbing materials. In lean condition (excessive oxygen) after warming up of the engine is completed, exhaust gas is led to the auxiliary passage 9 side, and NOx in exhaust gas is reduced by means of the treatment member 10 serving as a NOx reducing catalyst. However, when an exhaust temperature is more than a prescribed high temperature, exhaust gas is inhibited from being led into the auxiliary passage 9 so as to prevent crystals of the treatment member 10 from breaking up.