EGR control system for internal combustion engine, internal combustion engine, and EGR control method for internal combustion engine

摘要

PROBLEM TO BE SOLVED: To provide an EGR system of an internal combustion engine which can suppress the deterioration of the calculation accuracy of a NOx correction coefficient which is calculated on the basis of a detection value of a NOx concentration detection device arranged in an exhaust passage, can suppress the deterioration of the calculation accuracy of a control amount of an opening of an EGR valve, and can prevent the pasting of the opening of the EGR valve, and provide the internal combustion engine and an EGR method of the internal combustion engine.SOLUTION: When both an actual detection value m of a suction air flow rate sensor 21 and an actual detection value λ of an exhaust lambda sensor 24 are included in a preset detection value use range AR on the basis of the detection value of the suction air flow rate sensor 21 and the detection value of the exhaust lambda sensor 24, a NOx correction coefficient NCf is calculated on the basis of these actual detection values m and λ, and an actual detection value Nd of the NOx concentration sensor 20, and an opening of an EGR valve 16 is controlled on the basis of the calculated NOx correction coefficient NCf.SELECTED DRAWING: Figure 2