| 摘要 |
PURPOSE:To enhance both starting-performance and idle-running-stability by operating a pressure reducing means when the engine speed or engine load is lowered. CONSTITUTION:When the engine speed or load, which is indicated by the detecting signals from a engine speed sensor 23 and an exhaust pressure sensor 24, is low, including the idle running, or when the engine revolving speed is lower than 2,000rpm and the exhaust pressure is lover than 150mmHg, an exciting coil 21 is electrified so as to operate a pressure reducing means 22, thereby opening a waist gate valve 12. Thus,the differential pressure between the pressure in an exhaust passage 3 situated upstream with respect to a pressure wave supercharger 4 and that in an intake air passage 2 situated downstream with respect to the pressure wave supercharger 4 is greatly reduced, thereby reducing the exhaust return ratio. |
