US Patent 7121268 Electronic EGR gas control system

A curved passage constituting part of an exhaust gas recirculation passage is installed inside a suction passage in the downstream of an electronic control throttle valve, of which initial position is the fully opened position, and an exhaust gas recirculation flow control valve is installed in the cylindrical portion extending coaxially from the curved passage into a suction passage. The control valve is a butterfly valve driven by a motor via a reduction gear mechanism. In addition, the control valve opening is sensed by a sensor and cooled exhaust gas flow is sensed by a flow sensor at the outlet of an exhaust gas cooler, and the control of the control valve is based on these sensor signals.