EGR estimation apparatus for internal combustion engine and EGR estimation method for internal combustion engine

摘要

PROBLEM TO BE SOLVED: To provide an EGR estimation device for an internal combustion engine and an EGR estimation method for the internal combustion engine capable of estimating an EGR rate by using an intake oxygen concentration sensor while absorbing effects of a deterioration degree and an individual difference.SOLUTION: An estimation device 100 includes an internal combustion engine 1, an intake passage 11, an exhaust passage 21, a supercharger 30, an EGR device 40, an intake oxygen concentration sensor 16 and a controller 80. When the operating state of the internal combustion engine 1 is in a first operating region, the controller 80 acquires output from the intake oxygen concentration sensor 16. When the operating state of the internal combustion engine 1 is in a second operating region, the acquired output from the intake oxygen concentration sensor 16 is used as a reference, and an EGR rate α is estimated based on the output from the intake oxygen concentration sensor 16.SELECTED DRAWING: Figure 1