EXHAUST EMISSION CLEANING DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission cleaning device for an internal combustion engine capable of maintaining NOx purifying performance at high level by increasing chance of rich spike execution.

SOLUTION: This exhaust emission cleaning device performs rich spike when catalyst temperature T of NOx occlusion catalyst 33 is above temperature for starting catalyst activity and at catalyst temperature at which it acts effectively in NOx discharge and reduction when a rich spike demand is outputted. Consequently, a chance for performing rich spike is given even in a temperature region (between T1 and T2) where catalyst performance utilized not yet starts to rise, and NOx cleaning performance is continuously kept at high level by increase of the chance of rich spike execution.

COPYRIGHT: (C)2005,JPO&NCIPI