Abstract: Detection of engine idling is preformed by detecting the position of a throttle valve corresponding to idling and discriminating an intake air flow rate in a range of idle air flow rate. A signal indicative of engine idling is produced when both the throttle valve is in idling position and the air flow rate is less than the idle air flow rate.

Abstract: A switch for sensing a preset position of a throttle valve in an internal combustion engine, includes a stationary casing, a plunger movably disposed in the casing, and a throttle lever secured to the throttle valve so as to be moved along with the throttle valve. A first contact is supported on the casing. A second contact is supported on the plunger in such a manner as to contact the first contact according to the movement of the plunger. The throttle lever is so arranged as to be able to move the plunger and as to encounter the casing when the throttle lever moves, whereby the first and second contacts contact according to the movement of the throttle valve and the casing stops the movement of the throttle valve.

Abstract: An internal combustion engine provided with an idling adjusting device including a by-pass air passage which by-passes a throttle valve in a main air passage. The engine is further provided with an auxiliary air introducing device which increases the cross-sectional area of the by-pass air passage as engine temperature and/or ambient air temperature are above respectively predetermined temperatures during starting operation of the engine.

Abstract: An EGR control system for a motor vehicle engine equipped with an electronically controlled fuel injection system is so arranged and constructed that EGR rate is controlled in accordance with the mutual action of pressure in an EGR passageway and venturi vacuum generated at a venturi in an intake passageway under urban area driving condition, whereas in accordance with the mutual action between the pressure in the EGR passageway and pressure in the intake passageway immediately downstream of an airflow meter forming part of the electronically controlled fuel injection system under suburban area driving condition.