SPEED CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PURPOSE:To enable the stable control of the number of engine revolutions by setting a control gain from the result of judgement as to whether the number appears within the predetermined time after engine start and as to whether the engine is in a stable fuel combustion state after start, and setting a control signal on the basis of the aforesaid gain and a deviation between engine speeds. CONSTITUTION:The speed control device of an internal combustion engine 1 controls the opening of a throttle valve 5 in such a way that ECU 8 regulates a power supply amount to the solenoid 6a of a control valve 6 in a bypass passage 7 so provided as to bypass the throttle valve 5 in an intake passage 3. According to the aforesaid construction, the idling speed of the engine 1 is maintained at a target value. In this case, ECU 8 obtains a deviation between an actual speed obtained with an engine speed sensor 15 and a target speed determined on the basis of an operation mode. Also, judgement is made as to whether an engine speed occurs within the predetermined time after engine start, and whether the engine 1 is in a stable combustion state after start. A control gain is set on the basis of the result of the judgement. Furthermore, a control signal is set on the basis of the aforesaid deviation and control gain.