ABGASRÜCKFÜHRVORRICHTUNG FÜR EINEN VERBRENNUNGSMOTOR UND STEUERUNGSVERFAHREN FÜR DIE VORRICHTUNG

摘要

An exhaust gas recirculation device of an internal combustion engine (1) including a low-pressure EGR passage (20), a high-pressure EGR passage (21), a low-pressure EGR valve (23) and a high-pressure EGR valve (24) further includes an air-fuel ratio sensor (12) that is disposed in the exhaust passage (4) upstream of the position of its connection with the low-pressure EGR passage (20). In the case where a predetermined fuel-cut condition is satisfied, an ECU (30) estimates the flow amounts of exhaust gas flowing in the low-pressure EGR passage (20) and the high-pressure EGR passage (21), on the basis of the oxygen concentrations acquired by the air-fuel ratio sensor (12) at timings at which the exhaust gases recirculated into the intake passage (3) via the low-pressure EGR passage (20) and via the high-pressure EGR passage (21) reach the air-fuel ratio sensor (12), respectively.