Abstract: This invention relates to a valve for use in the automatic control of a vehicle and which may conveniently be powered from a vehicle speed monitoring electronic system. It is essentially a solenoid operated valve for vehicle control comprising a hollow body of non-magnetic material having an inlet and an outlet axially aligned with each other, valve seats at the inlet and outlet, a piston of magnetic material slidable in said body between positions closing the opening through either one or other valve seat, and a bore through the piston and in communication with a normally open outlet from the body. A considerable constriction is provided between the piston controlled inlet and the outlet from the body. The normally open outlet is suitable for connection to a vacuum operated servo-mechanism, the piston controlled outlet is suitable for connection to the vehicle engine vacuum line and the inlet is open to ambient atmosphere.

Abstract: A method of and apparatus for controlling the operation of a vehicle by electrical signals generated in a manner dependent on the road speed of the vehicle wherein the method comprises setting up a specific magnetic field in association with a normally unmagnetized component of the vehicle which rotates at a speed proportional to the road speed of the veicle and sensing variations in the magnetic field in a coil located on the opposite side of a ferromagnetic member of the vehicle to the component and amplifying the signal through a high gain amplifier.