| 摘要 |
PURPOSE:To prevent the overheating of a motor, by changing, when an idling revolution speed has reached a target value, an exciting current that is to be fed to a stepping motor, into a pulse signal that is of a higher frequency than the one at the time of drive, and also repeating an action in which every its plural pulses is alternately given in forward and backward revolution directions. CONSTITUTION:A control valve 5 driven by means of a hybrid form stepping motor 4 is provided at an auxiliary air passage 3 provided by bypassing a throttle valve 2 at an air intake pipe passage 1, and the stepping motor 4 is driven in control according to the pulse signal number of an exciting current being sent from an electronic type controller 6. As a result, when the valve body of the control valve 5 has reached a target position, changeover into a pulse signal which is of a high speed drive frequency in comparison with the previous drive frequency, is made, and arrangement is made so that an action in which every its plural pulses is supplied to all winding alternately in forward and backward revolution directions, may be repeated. As a result, the control valve 5 is conducted with high speed reciprocating movements at a small range, and the lowering of a winding temperature is realized. |
