Emission control device for internal combustion engine, has primary catalytic converter whose temperature is lower than/higher than activation temperature of secondary catalytic converter, while clearance is high value or small value

摘要

The device (1) has a setting unit (7) which adjusts target storage amount of reducing agent fed from the feed device (6) to the primary catalytic converter (4), while a corresponding clearance is provided between the target storage amount of reducing agent and corresponding maximum storable amount of reducing agent. The corresponding clearance is a relatively high value in lower temperature region and small value in higher temperature region of primary catalytic converter whose temperature is lower than/higher than activation temperature of secondary catalytic converter (5).