EXHAUST GAS REFLUX UNIT FOR ENGINE

PURPOSE:To upgrade control accuracy by providing a throttle part which feed-back controls the reflux of exhaust gas for engine and by installing therein a control valve which opens and closes in proportion to the reflux rate of the exhaust gas. CONSTITUTION:A suction air channel 2 and an exhaust air channel not illustrated in this figure are communicated to a reflux channel 4 having a reflux control valve 5. The channel 4 is also provided with a throttle part 12, while the throttle part 2 is equipped with a control valve 16 which makes the reduction area varable. A control unit receives signals from a rotational speed sensor 10, a suction air negative pressure sensor 11 and furthermore a first pressure sensor 13 and a second pressure sensor 14. The control unit 9 outputs signals which makes measured values equivalent to the target value stored in (a) memory 15. A negative pressure solenoid valve 7 and an ambient pressure solenoid valve 8 are opened and closed in proportion to the signals. The reflux control valve 5 operates under feed back control, while the control valve 16 moves downward when the reflux rate is decreased and vice versa.