Abstract: A vehicle speed control system is disclosed in which a signal Vs representing actual vehicle speed is, when the vehicle is running at a desired speed, momentarily fed into, and then stored in, a memory. The memory therefore produces a signal representing desired speed. An error amplifier compares the signal Vm with a signal Vf which represents actual vehicle speed and which is derived from Vs via a filter. Any speed error causes a drive circuit to adjust the throttle of the vehicle engine so as to tend to correct the vehicle speed error. The vehicle-speed-dependent signal Vf is derived from the actual speed of the engine of the vehicle, and this signal is also fed to a comparator which compares it with a reference signal Vr representing an upper or lower limit for engine speed. When the comparison indicates that the engine speed has exceeded the level represented by the reference Vr (e.g.

Abstract: A vehicle speed system is described in which an electrical signal representing actual vehicle speed is compared with a stored signal representing desired vehicle speed. Any speed error is used in a servo loop to generate a control signal which tends to reduce the error to zero. In addition, signals representing the actual and desired vehicle speeds are compared in a comparator unit so as to produce a disabling signal when the actual vehicle speed either exceeds the desired speed by more than a predetermined amount, or falls below the desired speed by more than a predetermined amount, (e.g. because road conditions prevent the vehicle engine from driving the vehicle at or close to the desired speed). This enabling signal is used to switch the control system out of operation.

Abstract: A system for controlling the speed of a motor vehicle comprises means deriving a first electrical signal having a mean level related to the actual speed of the vehicle and an alternating component whose amplitude is related to the actual speed of the vehicle, means storing a second electrical signal having a mean level related to a desired value for the vehicle speed and substantially free of any alternating component, means arranged to compare the first and second electrical signals whereby to produce an error signal having a mean level related to the difference, if any, between the actual and desired vehicle speeds and an alternating component related to the actual vehicle speed, and speed correcting means responsive to the amplitude of the error signal for correcting the actual speed of the vehicle.

Abstract: A system for controlling the speed of a motor vehicle has a speed detector which produces a first electrical signal having a mean level relating to the actual speed of the vehicle and an alternating component whose amplitude is also related to the actual speed of the vehicle. A memory is provided for storing a second electrical signal which has a mean level related to the required vehicle speed and which is substantially free of any alternating component. A comparator compares the first and second electrical signals and therefore produces an error signal which has a mean level corresponding to the difference (if any) between the actual and required vehicle speed and an alternating component related to the actual vehicle speed. A servo responds to the amplitude of the error signal to adjust the actual speed of the vehicle towards the required value.

Abstract: In an electronic speed responsive system for a motor vehicle, a first voltage proportional to an actual speed of the vehicle is compared with a reference voltage representing a desired cruise speed in order to produce an output error signal related to the difference between said first voltage and said reference voltage, the desired cruise speed is stored in a memory, and a control logic and safety circuit for rendering the system operative and inoperative has a memory cancel facility which cancels the previously memorized cruise speed stored in the memory when a driver of the vehicle makes an action associated with bringing the vehicle into, or preparatory to driving the vehicle from, a parked condition.