Patent ID: 8302583

Claim:
An exhaust gas recirculation system for an internal combustion engine, comprising: an external EGR passage which is connected to an exhaust passage of the internal combustion engine and an intake passage of the internal combustion engine and through which a portion of exhaust gas that flows through the exhaust passage is recirculated back to the intake passage as external EGR gas; an external EGR adjustment unit that adjusts an amount of external EGR gas that flows through the external EGR passage; an internal EGR adjustment unit that adjusts an amount of internal EGR gas which is a portion of combustion gas generated in the internal combustion engine and which is caused to remain in a cylinder of the internal combustion engine or caused to flow back from the exhaust passage in to the cylinder; and an EGR control unit that first adjusts the amount of external EGR gas using the external EGR adjustment unit so that an amount, by which the amount of internal EGR gas is adjusted, falls within a predetermined range, and then adjusts the amount of internal EGR gas using the internal EGR adjustment unit when the amount, by which the amount of internal EGR gas is adjusted, falls within the predetermined range in order to execute a feedback control so that an EGR rate, which indicates a proportion of EGR gas including the external EGR gas and the internal EGR gas to intake air that is supplied to the internal combustion engine, matches a target EGR rate, wherein the EGR control unit retards timing at which fuel is injected into the cylinder when the amount of internal EGR gas is increased by the internal EGR adjustment unit, and the EGR control unit advances the timing at which the fuel is injected into the cylinder when the amount of internal EGR gas is decreased by the internal EGR adjustment unit.