| 摘要 |
PURPOSE:To have a highly accurate control by exciting the exciter coil of a step motor for control of the amount of bypassing air flow by the two-phase simultaneous exciting system in order to approach the number of revolutions in idling and by repeating ONs only when the number is high. CONSTITUTION:An electronic control unit 61 is to control the number of revolutions in idling by controlling the amount of air flow in the bypass pipe using a step motor. Because two-phase exciting system is incorporated in this step motor, the driving force is raised. While this motor is at a standstill the stator coil 53 is not excited to assure a reduced amount of power consumption, and further the electronic control unit 61 will not be overheated. When the revolving speed of the engine is higher, i.e. the step motor sustains vibrations in a rather large magnitude, only the stop phase exciter coil II is supplied with current to have a repeated ON and OFF, whereby uncontrolled movement of the rotor cylinder is prevented even when the attractive force applied to the rotor 21 cylinder and the stator's magnetic pole valve is weak. Thus a stable control is obtained. |
