Exhaust gas recirculation system for diesel engine

In an automotive power plant comprising a diesel engine having an air intake passage means and an exhaust passage means, an EGR passage means extending between the air intake passage means and the exhaust passage means, an EGR control valve for selectively closing and opening the EGR passage means, a first actuator for driving the EGR control valve, means for regulating the flow of air being sucked through the air intake passage means, and a second actuator for driving the regulating means, said EGR control valve when opened during a particular engine operating condition permitting a portion of exhaust gases emitted from the engine to be recirculated therethrough by way of the EGR passage means while the regulating means is operated to reduce the rate of flow of the air through the air intake passage means, the improvement which comprises a detector device for detecting an operating condition of the engine and a control device operable in response to an output from the detector device to control the operation of the first and second actuators, said control device having a time lag providing means for delaying the operation of the first actuator relative to the operation of the second actuator thereby to open the EGR control valve after the increase of the rate of flow of the air being sucked through the air intake passage means when the circulation of the exhaust gases through the EGR passage means is to be interrupted.