EGR-gas flow rate estimation apparatus for internal combustion engine

摘要

A provisional EGR gas flow rate estimation unit estimates the flow rate of EGR gas passing through an EGR control valve based on the pressure of compressible fluid upstream and downstream of a throttle portion. An EGR gas flow rate estimation unit estimates the flow rate of EGR gas flowing from an exhaust circulation pipe into an intake passage by correcting an error in the provisional EGR gas flow rate. Error in the estimated provisional EGR gas flow rate is caused by pipe friction between the exhaust circulation pipe and EGR gas.