Patent ID: 7801669

Claim:
An exhaust gas control system for an internal combustion engine, comprising: a turbocharger that includes a compressor provided in an intake passage of an internal combustion engine and a turbine provided in an exhaust passage of the internal combustion engine; a high-pressure EGR device that has a high-pressure EGR passage which connects a portion of the exhaust passage, which is upstream of the turbine to a portion of the intake passage, which is downstream of the compressor, and that returns part of exhaust gas to the internal combustion engine through the high-pressure EGR passage; a low-pressure EGR device that has a low-pressure EGR passage which connects a portion of the exhaust passage, which is downstream of the turbine to a portion of the intake passage, which is upstream of the compressor, and that returns part of the exhaust gas to the internal combustion engine through the low-pressure EGR passage; and a control portion that controls a mixture ratio between the exhaust gas recirculated by the high-pressure EGR device and the exhaust gas recirculated by the low-pressure EGR device based on a correlation between the mixture ratio and a fuel consumption rate of the internal combustion engine while switching use of the high-pressure EGR device and use of the low-pressure EGR device or using the high-pressure EGR device and the low-pressure EGR device in combination, wherein a proportion of an amount of exhaust gas recirculated by the low-pressure EGR device to a total amount of exhaust gas recirculated increases as a load placed on the internal combustion engine increases.