Abstract: In a vehicle speed control apparatus for an internal combustion engine vehicle, in which the first amount of fuel supply required for maintaining the vehicle speed at a desired speed and the second amount of fuel supply corresponding to the amount of depression of an accelerator pedal are separately calculated, the apparatus comprises a selector for selecting the larger of the first and second amount of fuel supply to control the fuel adjusting member, and a modifying circuit for modifying the output data showing the first amount of fuel supply to cause it to slowly change, taking into account the value of the second data showing the second amount of fuel supply just before the second amount of fuel supply becomes smaller than the first amount of fuel supply, whereby the vehicle speed is prevented from being rapidly decelerated when the mode of vehicle speed control is changed from that by the second data to that by the first data.

Abstract: An apparatus for controlling the rotational speed of an internal combustion engine has a circuit for producing a signal corresponding to the difference between the actual engine speed and the target engine speed and a processor for weighting this signal by a factor that continuously changes according to the magnitude of the difference. The weighted signal is converted to a control signal for adjusting the speed of the engine.

Abstract: In an apparatus for controlling the speed of a vehicle driven by an internal combustion engine so as to maintain the vehicle speed at a target vehicle speed, the apparatus has a load detector for detecting the load condition of the engine at each instant and the PID control characteristics for the engine speed control are changed in accordance with the result detected by the load detector whereby the actual vehicle speed is maintained at the desired speed with high response characteristics.