Patent ID: 8387593

Claim:
An EGR flow rate control apparatus of an internal combustion engine, comprising an EGR flow channel that communicates an exhaust pipe with an intake pipe, a gas flow rate regulating valve that is installed in the EGR flow channel and that regulates an EGR gas flow rate, and a gas flow rate measurement apparatus that is installed on an intake pipe side with respect to the gas flow rate regulating valve in the EGR flow channel and that measures the EGR gas flow rate flowing through the EGR flow channel; wherein the EGR flow rate control apparatus comprises gas flow rate correction means that corrects the EGR gas flow rate based on a first operating state parameter relating to pressure fluctuations in the intake pipe or the exhaust pipe of the internal combustion engine, and a second operating state parameter relating to a flow channel resistance in the EGR flow channel, wherein the gas flow rate correction means corrects the EGR gas flow rate using, as the first operating state parameter, at least one of a number of revolutions of the internal combustion engine, a load of the internal combustion engine, a target torque, a fuel injection amount, an intake pipe pressure, a throttle valve opening degree, and an exhaust pipe pressure, and using, as the second operating state parameter, at least one of a degree of opening of the gas flow rate regulating valve, the EGR gas flow rate, the number of revolutions of the internal combustion engine, the load of the internal combustion engine, and the target torque, and wherein the gas flow rate correction means increases a correction amount of the EGR gas flow rate in such a manner that the EGR gas flow rate increases as a pulse frequency of the EGR gas flow rate increases.