EXHAUST EMISSION CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE, INTERNAL COMBUSTION ENGINE AND EXHAUST EMISSION CONTROL METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control system for an internal combustion engine having an upstream side oxidization catalyst device and a downstream side lean NOx trap catalyst device on an exhaust passage of the internal combustion engine in which a control over increasing in temperature of exhaust gas for recovering an exhaust emission control capability of each catalyst device enables avoidance of a lack of increased temperature of each catalyst device, overshooting at the time of increased temperature, heat degradation and erosion of the catalyst and enables a positive execution of regeneration processing, and provide the internal combustion engine and an exhaust emission control method for the internal combustion engine.SOLUTION: A measuring position for a control temperature Tc that is a control amount in a feed-back control during temperature increasing control is changed in reference to an excess air factor λ or oxygen concentration Co of exhaust gas Ga passing through an exhaust passage 15 when the temperature increasing control for the exhaust gas Ga is carried out under regenerative control for recovering a purifying capability of an exhaust emission control system 20.SELECTED DRAWING: Figure 2