| 摘要 |
PROBLEM TO BE SOLVED: To prevent any bounceback phenomenon from occurring by making at least one side of driving frequency and driving voltage of a step motor smaller than in time of auxiliary air quantity control at the time of initialization accommodating the operating pulse number of the step motor being related to an auxiliary air regulating valve, to a valve opening position. SOLUTION: In a device which controls the opening of an idle adjusting valve V or an auxiliary air regulating valve with a step motor M in a bypass passage 4 bypassing a throttle valve 3, for example, just after an ignition switch is interrupted, an initializing process accommodating the operating pulse nor of the step motor M, to an opening position of the idle adjusting valve V is executed. At this process, the idle adjusting valve V is driven to either of both valve closing and opening limits of the idle adjusting valve V. At this time, at least one side of driving frequency and driving voltage of the step motor M is made smaller than in time of auxiliary air quantity control by the idle adjusting valve V, whereby any bounceback phenomenon is avoided. |
