Engine idle air control valve with position counter reset apparatus

摘要

A vehicle is driven by an internal combustion engine having an air induction passage with an idle air control valve positionable by a stepping motor in response to valve opening and valve closing pulses. A counter normally counts the pulses arithmetically to provide an indication of valve position. In order to bring the counter and valve position into accord, counter reset apparatus is effective, when actuated, to generate a predetermined number of valve closing pulses sufficient to stall the stepping motor against the stop, reset the counter to a predetermined reference count and generate a predetermined number of valve opening pulses to return the idle air control valve to a desired operating position with the counter counting such pulses in the normal manner. The apparatus is actuated upon the first occurrence of a vehicle speed greater than a predetermined speed such as 30 mph following a counter reset signal, which signal is generated upon each engine start and may further be generated at any time a counter error is detected. The minimum required vehicle speed guarantees that the engine will not stall during the period of the reset operation.