Closed-loop fluidic control system for internal combustion engines

A closed-loop fluidic control system for an internal combustion engine having a variable Venturi carburetor whose inlet is coupled to a source of combustion air, fuel being fed into the carburetor to intermingle with the air passing therethrough to produce an air-fuel mixture which is fed into the intake manifold of the engine, said Venturi including an axially-shiftable spool whose position affects flow velocity through the Venturi, said system automatically adjusting the axial position of the spool to produce a ratio of fuel-to-air that is optimum for prevailing conditions of engine speed and load, said system comprising:

• A. a vacuum amplifier coupled to the intake manifold and responsive to the existing pressure differential between the inlet and throat of the Venturi to derive from the prevailing vacuum in the manifold vacuum an amplified output vacuum which is a function of said pressure differential;
• and
• B. a bi-directional vacuum motor energized by said amplified output vacuum and operatively linked to the spool to vary the axial position thereof in a direction and to an extent providing the desired fuel-to-air ratio.