Control for idle speed control valve

摘要

An idle speed control valve is provided in a bypass path of an intake system and has its opening controlled by control pulse signals. The idle speed control valve is designed to increase the opening in proportion to the increase or decrease of the duty ratio of the control pulse signal and completely close the opening at 0% or 100% of the duty ratio. According to this invention, to completely close the idle speed control valve, instead of sending the control pulse signal of 0% or 100% of duty ratio to the idle speed control valve, the transmission of the control pulse signal is interrupted or the idle speed control valve is driven by continuous direct current.