Abstract: A governor circuit for limiting the maximum speed of an internal combustion engine is effective to minimize overshoot at all ranges of engine acceleration. The system includes a circuit responsive to the engine speed which provides control signals to a solenoid valve which, in turn, controls a vacuum actuator which can override a manual throttle control to move the throttle toward closed position when a governed engine speed is approached. A control circuit provides a signal having a lead component and an integrated signal which comprises a stabilizing component and an integrated speed component. The integrated signal is provided by an integrator having a low sensitivity and high gain at low engine accelerations and a high sensitivity and low gain at engine accelerations above a predetermined switch point. The resulting control signal controls a duty cycle oscillator which actuates the solenoid valve.

Abstract: A system for limiting the speed of a gasoline engine includes a circuit responsive to the engine speed which provides control signals to a solenoid valve which in turn controls a vacuum actuator. The vacuum actuator then overrides a manual throttle control to move the throttle toward closed position when a governed engine speed is approached. A control circuit provides a signal having four components; one proportional to engine speed, second and third proportional to engine acceleration and a fourth which is the integrated difference between the engine speed and a preset governed speed. In addition a speed switch actuated when an overspeed condition occurs is effective to inhibit the third component and to increase the fourth component to its maximum value to effect maximum governing action and system stability. The control signal controls a duty cycle oscillator which actuates the solenoid valve.

Abstract: An engine speed governor for an engine having a multi-stage carburetor includes vacuum operated first and second governor actuators operatively connected to the primary and secondary throttle valves, respectively, of the carburetor and connected by separate conduits to the primary intake passage of the carburetor for venturi vacuum to effect selective closing of the primary and secondary throttle valves, and a solenoid governor valve having a normally open, first port operatively connected to the first governor actuator, a normally closed, second port operatively connected to the second governor actuator and a third port open to the atmosphere, the solenoid governor valve being connected to an engine speed sensing means whereby when the engine is below governed speed, the solenoid governor is de-energized, allowing air to bleed into the first governor actuator to keep it in a non-governing position while allowing vacuum to build up in the second governor actuator for normal operation of the secondary throttle

Abstract: A system for limiting the speed of a gasoline engine includes a circuit responsive to the engine speed which provides control signals to a solenoid valve which in turn controls a vacuum actuator. The vacuum actuator then overrides a manual throttle control to move the throttle towards closed position when a governed engine speed is approached. The control circuit provides a signal having three components: one proportional to engine speed, a second proportional to engine acceleration and a third which is the integrated difference between the engine speed and a preset governed speed. In addition, the third signal is high at low engine speed and gradually diminishes as engine speed increases to intermediate or high values. The control signal controls a duty cycle oscillator which actuates the solenoid valve. The duty cycle oscillator is inhibited at low speeds to prevent interference with manual throttle control.