METHOD OF ESTIMATING QUANTITY OF N2O PRODUCED IN AMMONIA OXIDATION CATALYST AND EXHAUST GAS PURIFICATION SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

An object of the invention is to estimate the quantity of N 2 O produced in an ammonia oxidation catalyst in a case where the ammonia oxidation catalyst is provided in an exhaust passage of an internal combustion engine. In a case where an ammonia oxidation catalyst 14 having the function of oxidizing ammonia is provided in an exhaust passage 6 of an internal combustion engine 1, the quantity of N 2 O produced in the ammonia oxidation catalyst 14 is estimated based on the difference between a measurement value of an upstream NOx sensor 17 provided in the exhaust passage 6 upstream of the ammonia oxidation catalyst 14 and a measurement value of a downstream NOx sensor 18 provided in the exhaust passage downstream of the ammonia oxidation catalyst 14.