EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To surely emit and reduce NOx in NOx occluding and reducing catalyst, and to reduce the quantity of reductant discharged from the NOx occluding and reducing catalyst. SOLUTION: NOx occluding and reducing catalyst 14 with which an air-fuel ratio can burn a lean mixture in a combustion chamber is located in an exhaust passage of an internal combustion engine. Reductant is intermittently fed from a reductant supply device 17 located in an exhaust pipe 13 upstream of the NOx occluding and reducing catalyst 14, to the latter so as to reduce NOx in the same. The reductant supply device 17 can change the reductant jetting pressure so that the reductant jetting pressure is set to be higher when the intake air volume is large than when the intake air volume is small.