Exhaust gas purification device for internal combustion engine

• Main Authors: ISHIHARA KOUJI, MITSUMOTO HISASHI
• Format: Patent
• Language: English
• Published: 16.01.2001
• Edition: 7
• Subjects: BLASTING; COMBUSTION ENGINES; COMBUSTION ENGINES IN GENERAL; CONTROLLING COMBUSTION ENGINES; 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; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; INTERNAL-COMBUSTION PISTON ENGINES; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; STEAM ENGINES; WEAPONS

In a device for purifying an exhaust gas mixture from an engine, a catalyst traps and reduces NOx in dependence of the air fuel ratio of the exhaust gas mixture from the engine. A controller detects a predetermined condition to initiate a catalyst regenerating control to reduce NOx in the catalyst, and controls the engine in a catalyst regeneration control mode when the predetermined condition is detected. In the catalyst regeneration control mode, the controller sets the fuel injection timing on the compression stroke and the fuel injection quantity at a level to make the average air fuel ratio in a combustion chamber equal to or leaner than the stoichiometric ratio and to produce a rich air fuel mixture region richer than the stoichiometric ratio in the vicinity of a spark plug.