Patent ID: 6945240

Claim:
An exhaust gas recirculation apparatus for an internal combustion engine mounted with a turbocharger in which a turbine is disposed in an exhaust passage and a compressor is disposed in an intake passage, comprising: a passage opening and closing device that opens or closes an exhaust gas recirculation passage communicating the exhaust passage on the upstream side of said turbine with the intake passage on the downstream side of said compressor; a shutter that opens or closes a port formed on the intake passage on the downstream side of said compressor; a butterfly valve disposed in an intake air return passage that returns intake air from said port to the intake passage on the upstream side of said compressor, an opening angle of said butterfly valve being controlled in multi-step fashion between fully open and fully closed petitions; an operating condition detecting device that detects an engine operating condition; and a control unit that incorporates a microcomputer therein, wherein said control unit determines whether or not the exhaust gas is to be recirculated based on the engine operating condition detected by said operating condition detecting device, and when it is determined that the exhaust gas is to be recirculated, said control unit operates said passage opening and closing device to open said exhaust as recirculation passage and simultaneously operates said shutter to open said port and controls the opening angle of said butterfly valve in accordance with the detected engine operating condition.