| 摘要 |
PURPOSE:To prevent overrun of a main supercharger at the time of operation on a high land, and to smoothly perform switching from the operation condition of only the main supercharger (single supercharging stage) to the operation condition of both main and auxiliary superchargers (double supercharging stage.). CONSTITUTION:There are provided, in an engine 1, main and auxiliary superchargers 10,11 intake and exhaust changeover valves 24,23, an exhaust bypass valve 32, an intake air pressure sensor 62, an air-flow meter 63, an atmospheric air pressure sensor 69 and the like. When a real intake air quantity exceeds an changeover intake air quantity, a CPU opens both changeover valves 24,23, may be switched, so that a single supercharging stage may be switched to a double supercharging stage. CPU also slightly opens an exhaust bypass valve 32 before switching of the stages, so as to force an auxiliary turbocharger 11 to make approach-run rotation based on the real supercharged pressure, and adjusts two supercharging stages to set supercharged pressures. The CPU determines set supercharged pressures and the switched intake air quantity smaller and the atmospheric pressure indicated by an atmospheric pressure sensor 69 becomes lower. |
