EGR control apparatus and EGR control method for internal combustion engine

An EGR control apparatus for an internal combustion engine in which part of exhaust gases is recirculated into an intake passage via a low-pressure EGR valve of a low-pressure EGR device, and part of the exhaust gases is recirculated into cylinders via a high-pressure EGR valve of a high-pressure EGR device, comprising:

• error parameter calculation means for calculating an error parameter indicating an error of a total EGR amount which is a total sum of a low-pressure EGR amount as an amount of gasses recirculated by said low-pressure EGR device and a high-pressure EGR amount as an amount of gasses recirculated by said high-pressure EGR device;
• correction value calculation means for calculating a low pressure-side correction value and a high pressure-side correction value such that an absolute value of the error of the total EGR amount indicated by the error parameter is reduced;
• target opening degree calculation means for calculating a target low-pressure EGR opening degree serving as a target of a degree of opening of the low-pressure EGR valve, and a target high-pressure EGR opening degree as a target of a degree of opening of the high-pressure EGR valve, using the low pressure-side correction value and the high pressure-side correction value, respectively;
• and
• EGR control means for controlling the degree of opening of the low-pressure EGR valve and the degree of opening of the high-pressure EGR valve such that the degree of opening of the low-pressure EGR valve and the degree of opening of the high-pressure EGR valve become equal to the target low-pressure EGR opening degree and the target high-pressure EGR opening degree, respectively,
• wherein at least one of the low pressure-side correction value and the high pressure-side correction value is configured to include a feedback correction value that is calculated using a predetermined feedback control algorithm such that an absolute value of the error is reduced, and a learned value that is learned when a ratio between the low-pressure EGR amount and the high-pressure EGR amount in the total EGR amount is in a predetermined state.