Exhaust emission control device of internal combustion engine

摘要

An exhaust emission control device of an internal combustion engine includes a fuel supply unit provided in a fuel supply passage, for supplying a reducing agent directly to a NOx trap catalytic converter; an addition pressure detection unit (42) for detecting the supply pressure of the reducing agent supplied by the fuel supply unit; and a controller (50) for calculating the amount of NOx adsorbed by the catalytic converter. When the supply pressure of the reducing agent is almost zero (54), the controller prohibits calculation of NOx adsorption amount depending on the supply of the reducing agent (56), creates a rich state in a cylinder (58), carries out calculation of NOx adsorption amount depending on the created rich state (52), and causes release and reduction of the adsorbed Nox.