EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a catalyst exhaust emission control device for an internal combustion engine capable of further improving exhaust emission control performance by utilizing oxygen occluding capacity of an exhaust emission control catalyst. SOLUTION: This catalyst exhaust emission control device for the internal combustion engine 1 utilizes an oxygen occluding action of the exhaust emission control catalyst 19 disposed on an exhaust passage 7 of the internal combustion engine 1 provided with an engine stopping mode to be stopped during the operation of a vehicle. The device is provided with occluding amount calculation means 18 and 25 for calculating oxygen occluding amount of the exhaust emission control catalyst 19 and an air-fuel ratio control means 18 for performing an air-fuel ratio control of the internal combustion engine 1 based on the oxygen occluding amount calculated by the occluding amount calculation means 18 and 25. The occluding amount calculation means 18 and 25 calculate oxygen occluding amount also during the engine stopping mode of the internal combustion engine 1. The air-fuel ratio control means 18 performs an air-fuel ratio control when restarting the engine after releasing the engine stopping mode based on oxygen occluding amount calculated during the engine stopping mode by the occluding amount calculation means 18 and 25.