Abstract: Charge forming apparatus such as a carburetor of the fluid jet type in which fuel is supplied to a pair of tubular members, which may be of equal or different diameters, disposed across a housing opening through which air flows, the velocity of which is controlled by a throttle valve or damper means. Each tubular member is constructed with a generally upwardly directed slot or fuel gap, such that the air strips fuel therefrom. Excess fuel from the tubular members is returned to the source. In the specific apparatus, one tubular member is located upstream in the housing from the other, the lower tubular member being located closely adjacent to the location of initial opening of the air throttle valve or damper. The throttle valve or damper may be of the iris type or of the type having a pair of vanes pivoted outwardly of the center thereof, so as to initially open at the center thereof.At small throttle openings, air flowing to the engine is concentrated over the fuel gap of the lower member.

Abstract: A fuel system in which excess fuel is recirculated from the charge forming apparatus. The apparatus comprises a regulator having a body with a fuel supply port connected to a fuel source, an outlet port for supplying fuel to a zone and a return port for receiving excess fuel from the outlet port and recirculating the excess fuel to the fuel supply. In addition, the apparatus may comprise temperature responsive means to vary the size of the return port to vary the quantity of excess fuel recirculated and thus the quantity of fuel supplied to the zone.

Abstract: In a system including a carburetor for regulating the air/fuel ratio fed to an internal combustion engine, a sensor is positioned in the exhaust pipe to provide a control signal indicating the amount of some exhaust gas constituent, such as oxygen. A control circuit is provided to regulate the position of a carburetor component, to change the air/fuel ratio as a function of the control signal derived from the exhaust gas sensor. This carburetor component is continually displaced, either toward a richer or leaner mixture condition, thus in effect integrating the signal from the exhaust gas sensor which ultimately regulates the air/fuel ratio. Operation of the control circuit is modified as a function of the engine speed and the engine temperature.

Abstract: Charge forming apparatus for an internal combustion engine of the type in which a fuel dispersion gap is subjected to impingement by an inducted air stream is provided with pneumatic control means for varying the area of the fuel dispersion gap. An additional feature of the invention includes regulation of back pressure on the fuel.

Abstract: A fuel system in which excess fuel is recirculated from the charge forming apparatus, including means for regulating pressure of the recirculated fuel which in turn influences the air-fuel ratio of the charge forming apparatus. One embodiment of the regulator includes manual adjusting means for maintaining a stable pressure and air-fuel ratio, while another embodiment includes an electronically controlled transducer for varying the pressure and air-fuel ratio while the engine is operating.