Abstract: A suction control device for a multiple cylinder internal combustion engine comprising a shell body presenting a suction path communication to each cylinder in a multiple cylinder internal combustion engine, a rotary shaft (21a) penetrating and born by the shell body, a butterfly valve (21) supported by the rotary shaft and provided in each of the suction paths so that it can freely open or close the suction path, and a restricting means for restricting movement of the rotary shaft in the axial direction; wherein the rotary shaft and the butterfly valve are monolithically formed with a resin material, the shell body is made from a resin material, and the restricting means comprises an expanding piece (21b) monolithically formed on the rotary shaft and having a width in the radial direction thereof, a contact wall (24) formed on the shell body and slidably contacting and supporting the expanding piece, and a resilient energizing member (33) for energizing the expanding piece to contact it to the contact wall.

Abstract: An apparatus for controlling an engine speed through intermittent control of a driving time and a halt time for an engine-speed adjusting actuator (12) in accordance with the output signal of a difference detecting circuit (6) corresponding to the difference between the outputs of a desired speed computing circuit (5) and an actual speed computing circuit (4). The feature of the invention resides particularly in determining the actuator halt time in proportion to the desired quantity of control for the actuator (12) or the engine operation parameter without limiting the said time to any fixed length, hence eliminating overshoot of the engine speed in the control and ensuring satisfactory apparatus capabilities with a short halt time and enhanced response characteristic.

Abstract: The present invention is adapted for providing an idling speed control system of an internal combustion engine, which exhibits a good response for changes in an engine load, comprising: a throttle valve which controls the amount of intake air for the engine; an actuator which includes an electric motor for variably controlling the opening of the throttle valve; a rotation speed detector for detecting the rotation speed of the engine; an idling condition detector for detecting the idling condition of the engine; and a control, responsive to the detected output of the idling condition detector means, for generating feedback control pulses to intermittently drive said electric motor so that the detected rotation speed of the engine under the idling condition may converge into a target idling rotation speed while, responsive to the output of a detector that detects the operation condition of the engine load operated under the idling condition of the engine, or to the detected output of said rotation speed detecto