Abstract: The throttle for the air inlet passage of an automobile internal combustion engine comprises a variable restriction diffuser within the passage and designed for sonic velocity gas flow through its region of maximum restriction throughout substantially the entire operating range of the engine. The diffuser comprises an orifice member and a closure member movable axially in opposite direction within the passage to vary the aforesaid maximum restriction and operatively coupled with the throttle control linkage for such movement, whereby the force required to move either diffuser member against the force of the fuel and air inlet flow within the passage is counterbalanced by an oppositely directed force exerted by said flow on the other diffuser member.

Abstract: A carburetion system for supplying a fuel-air mixture to an internal combustion engine in a manner maintaining a desired ratio of fuel-to-air under varying conditions of operation to improve fuel economy and minimize the emission of pollutants. The system includes a carburetor having a tubular variable-Venturi structure whose effective cross-sectional areas are circular or annular, the converging inlet to the throat of the Venturi and the diverging outlet thereof having a configuration free of discontinuities regardless of the effective throat area. The Venturi areas and throat are varied by a control motor as a function of air flow that changes with engine demand. The fuel fed into the carburetor at the varying throat is metered by a valve whose effective orifice is varied by the motor concurrently with the change in Venturi throat area to maintain the desired ratio.

Abstract: An oxygen sensor is fitted to the exhaust pipe of a spark ignition internal combustion engine so that it projects into the exhaust gas stream. Its output is connected to a comparator circuit which has its output connected to the actuator of a variable airflow controller which controls airflow through an air supply passage which is connected to the fuel supply jet of an air valve carburetor between the fuel metering orifice and the fuel discharge nozzle of that carburetor. The comparator circuit emits an output when the oxygen sensor detects that the ratio of the air/fuel mixture fed to the engine by the carburetor is either richer or leaner than the stoichiometric ratio. The output from the comparator circuit drives the variable air flow controller in the appropriate direction to tend to return the ratio of the air/fuel mixture fed by the carburetor to the engine towards stoichiometry. An auxiliary air supply passage may be connected to the induction passage downstream of the throttle valve.

Abstract: A multi-stage carburetor has a primary throttle bore that is extended into the intake manifold in close proximity to the exhaust gas heated manifold floor, and a secondary bore that surrounds a portion of the primary bore and terminates at the inlet to the intake manifold so as to avoid a restriction to flow of secondary air into the manifold and past the primary passage.

Abstract: A variable venturi carburetor comprised of an open induction duct enclosing coaxial inside first and outside second venturi members. The second venturi member is axially movable relative to the first venturi member in response to operation of a throttle linkage to vary the volume and velocity of air passing through a restricted cross section between the two venturi members and into a downstream mixing chamber. Fuel, supplied from a float chamber within the induction duct, is released into the inwardly moving air through a fuel supply orifice and an idle fuel supply orifice. An idle air supply is provided to bypass the restricted cross section under idling conditions. Also, an intermediate phase bypass duct is provided to release air into the mixing chamber, in addition to air entering through the restricted cross section, during intermediate R. P. M. conditions.