Speed control for heavy duty trucks

Abstract From the Canadian patent

An automatic speed control for a vehicle having a source of compressed air, such as a heavy duty truck includes a logic controller, which controls a pair of solenoid valves to regulate communication between the compressed air source and an air actuated throttle. The controller is responsive to initiation of speed control by actuation of the appropriate switch by the vehicle operator to use inputs representing wheel speed (or engine speed) and the position of the vehicle throttle to generate an error signal. The controller compares the error signal with a signal representing a desired or memorized speed set by the vehicle operator and controls the air actuated throttle accordingly.