Patent ID: 8346462

Claim:
A malfunction detection apparatus for an EGR system comprising: a turbocharger that has a turbine in an exhaust passage of an internal combustion engine, and has a compressor in an intake passage thereof; a high pressure EGR device that includes a high pressure EGR passage connecting between the exhaust passage at a location upstream of said turbine and said intake passage, and a high pressure EGR valve for adjusting an amount of EGR gas flowing through said high pressure EGR passage; a low pressure EGR device that includes a low pressure EGR passage connecting between the exhaust passage at a location downstream of said turbine and said intake passage, and a low pressure EGR valve for adjusting an amount of EGR gas flowing through said low pressure EGR passage; and an opening degree detection device that detects the degree of opening of said high pressure EGR valve; wherein a detection unit is provided that detects a malfunction of said low pressure EGR device from the degree of opening of said high pressure EGR valve at the time when the EGR gas is supplied from both said high pressure EGR device and said low pressure EGR device, and at the time when said high pressure EGR valve is controlled in a feedback manner so as to direct an amount of EGR gas in a cylinder toward a target range of said amount of EGR gas, while carrying out open loop control of said low pressure EGR valve.