| 摘要 |
PURPOSE: To prevent the occurrence of an engine stall and overrun during disconnection of energization to an electromagnetic coil by setting flow rate characteristics to ensure a flow rate at which an engine is prevented from the occurrence of the engine stall to an engine in the position of a duty ratio specified % value at a rotary valve. CONSTITUTION: Energization to an electromagnetic coil 6 to drive a main valve 2 and a subvalve 3 to the opening side is disconnected and when only an electromagnetic oil 5 to drive the valves 2 and 3 to the closing side is worked on a permanent magnet 4, the valves 2 and 3 are moved to a full closing position. In which case, a flow rate on a duty ratio of 0% is set to a flow rate of 7m<3> /h, and auxiliary air in the flow rate is fed to an engine 13 through a bypass passage 14. Further, a flow rate in the duty ratio of 0% is set to a flow rate at which an engine 13 is prevented from the occurrence of an engine stall. Thus, even when energization to the electromagnetic oil 6 is cutoff owing to disconnection, an engine stall is reliably prevented from occurring. |
