Apparatus for converting a carburetor for gaseous fuel

Claim 1

A gaseous and liquid-fuel carburetor for an internal-combustion engine having a liquid-fuel carburetor with an inlet flange, an air cleaner housing, and an air cleaner, comprising: an adapter member for coupling to said carburetor inlet flange, and mixing means within said air cleaner housing coupled to said adapter member, said mixing means including an air inlet venturi nozzle for guiding air into said inlet flange, and means within said venturi nozzle for introducing gaseous fuel into the venturi for mixing with air, said air inlet venturi including a pair of upper and lower spaced plates defining a substantially continuous, circumferential venturi passage, said passage converging from an outer large entrance opening defined by smooth curved opposed corners on said plates to an intermediate narrow neck portion defined by elongated substantially parallel opposed surfaces on said plates, said surfaces downstream of said narrow neck portion smoothly diverging for a substantial length to an inner larger discharge opening, said means for introducing gaseous fuel being located at the closest spacing between said substantially parallel surfaces in said intermediate narrow neck opening, and downstream of said corners sufficient to be in substantially laminar flow, and wherein said smoothly curved corners, said substantially parallel surfaces of said narrow neck portion with the means for introducing the gaseous fuel located therein, and said smooth divergence to the discharge opening being capable of providing a low air pressure at the gaseous fuel introduction location but only a small total pressure drop across the entire venturi thereby maximizing fuel input and air input to the carburetor.