| 摘要 |
PURPOSE:To prevent the carbon contained in the circulative exhausted gas from attach ment to an opening/closing valve for high-speed suction port even in case the circula tive exhausted gas is introduced from upstream the opening/closing valve, which is resorted to as a measure to reduce NOx, by leading the air with a pressure near the atmospheric level to the areas around upstream and downstream the valve through a throttle valve. CONSTITUTION:In this exhaust turbocharger 13, the exhaust passage 14 upstream the exhaust turbine 13B is connected to the suction passage 12 upstream the divergent point of No.1. No.2 suction ports 27A, 27B at the cylinders, and an exhaust gas feedback passage 34 is provided being equipped with an exhausts gas feedback control valve 33. Also an air lead-in passage 35 is provided to connect the suction passage 12 upstream a throttle valve 17 to the areas around upstream and downstream an opening/closing valve 30, and the divergent path downstream said air lead-in passage 35 is equipped with orifices 35a, 35b. Thereby, in the range where the exhaust gas is fed back, the supercharge air with a pressure over the atomospheric given from the above-mentioned suction passage 12 upstream the throttle valve 17 is certainly supplied via passage 35 to the suction port 27A located in the neighborhood of the opening/closing valve 30 whereabout a neg. pressure is being generated. |
