| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine such as a diesel engine capable of reducing NOx in exhaust gas and suppressing worsening of the durability and fuel economy of the internal combustion engine to the minimum. SOLUTION: This exhaust emission control device 1 is provided with a first air-fuel ratio control means for changing an air-fuel ratio of exhaust gas of the diesel engine 2 which flows into an NOx storage reduction catalyst 10 when the amount of NOx stored in the NOx storage reduction catalyst 10 reaches a predetermined amount into the vicinity of a stoichometric air fuel ratio to release NOx from the NOx storage reduction catalyst 10 and a predetermined amount setting means for setting a predetermined amount in accordance with a load of the diesel engine 2. If the predetermined amount is set to a large amount in a high load region, operation frequency in the vicinity of the stoichiometric air fuel ratio can be reduced, and worsening of the durability and fuel economy of the diesel engine 2 can be suppressed to the minimum.</p> |
