System for regulating the idle speed of an internal combustion engine

摘要

A system for regulating the idle speed of an internal combustion engine with an electronic fuel injection system having a bypass around a throttle valve of the engine and a solenoid operated control valve provided in the bypass to control the volume of air flow passing the bypass. The system comprises an engine speed sensor for sensing the engine speed of the engine and for producing an engine speed voltage, an idle switch responsive to idle operation of the engine for producing an idle signal, and a reference voltage circuit for producing a reference voltage corresponding to a predetermined idle speed. Integrating circuits for producing regulating signals dependent on the difference between the engine speed voltage and the reference voltage. The regulating signals comprise a first signal the voltage of which rapidly increases and a second signal the voltage of which slowly increases. A change-over switch is provided to be responsive to the idle signal for applying the engine speed voltage to the integrating circuits. The regulating signals are applied to a driver for energizing the solenoid of the solenoid operated control valve to actuate the control valve to regulate the idle speed to the predetermined idle speed.