EXHAUST PURIFICATION SYSTEM OF AN INTERNAL COMBUSTION ENGINE

摘要

An exhaust purification system of an internal combustion engine comprising an ammonia oxidation catalyst device 3 and an ammonia holding device 4 arranged immediately upstream of the ammonia oxidation catalyst device is provided. The ammonia holding device has a solid acid, holds ammonia to restrain the ammonia from flowing into the ammonia oxidation catalyst device when a temperature of the ammonia oxidation catalyst device is within a N 2 O producing temperature range, and releases the held ammonia to make the ammonia flow into the ammonia oxidation catalyst device when the temperature of the ammonia oxidation catalyst device is out of the N 2 O producing temperature range.