| 摘要 |
PURPOSE:To switch smoothly a turbocharger in each rotational speed range by judging slight opening condition of an exhaust switching valve in a low rotational speed range by supercharging pressure, and judging its condition in a high rotational speed range by an intake air quantity. CONSTITUTION:In an engine 1 with a supercharger, when an exhaust switching valve 17 is opened slightly, an intake bypass valve 33 is closed so as to increase the approach rotational speed of an auxiliary turbocharger 8 before switching from supercharging operation by only a main turbocharger 7 into supercharging operation by both turbochargers 7, 8. In an engine control computer 29, the rotational speed of an engine 1 is detected so as to judge either it is in a low rotational speed range or in a high rotational speed range. When supercharging pressure by an intake pipe pressure sensor 30 reaches the set pressure in the low rotational speed range, slight opening of an exhaust switching valve 17 is started. On the other hand, when an intake air quantity by an air flow meter 24 reaches a set quantity in the high rotational speed range, slight opening of the exhaust switching valve 17 is started. It is thus possible to switch smoothly supercharging operation in the total rotational speed range. |
