Carburetion control apparatus

A carburetion control apparatus for an internal combustion engine having a conventional carburetor with a float chamber in which the level of the fuel is controlled to determine the rate of flow through an orifice into the intake manifold of the engine, the improvement comprising:

• a compound valve housing;
• means for forming an atmospheric pressure chamber within said housing having an inlet port opening to atmosphere, and an inlet-outlet port connected by tubing to the float chamber above the fuel level;
• means for forming a low pressure chamber within said housing having a limiter valve means within an inlet port opening to atmosphere, said limiter valve biased against atmospheric pressure a predetermined amount, and an outlet port connected by tubing to the intake manifold;
• means for forming an air bleed chamber within said housing, said air bleed chamber interconnecting said atmospheric pressure chamber and said low pressure chamber, and having an air bleed inlet port opening to atmosphere;
• means for supporting a diaphragm within said air bleed chamber, the low pressure side of the diaphragm facing said low pressure chamber and its high pressure side facing said atmospheric pressure chamber, said diaphragm supporting means having at least one aperture therein connecting the high pressure side of the diaphragm with said air bleed chamber;
• means for forming a bore within said housing connecting said low pressure chamber and the high pressure side of the diaphragm through said air bleed chamber and said at least one aperture;
• means for linking the diaphragm to a means for capping the atmospheric pressure chamber inlet, said capping means having means for biasing it away from said inlet and said linking means having mounted thereon a means for capping the interconnection between said atmospheric pressure chamber and said air bleed chamber;
• and
• an on-off valve mounted within the tubing to the intake manifold, said on-off valve opening only when the manifold pressure is a predetermined amount less than that at the low pressure chamber outlet port, whereby the diaphragm will simultaneously uncap the interconnection between the atmospheric pressure chamber and the air bleed chamber and cap the atmospheric pressure chamber inlet when pressure at the low pressure chamber outlet port is less than that at the low pressure chamber inlet port by a pre-determined amount thus reducing pressure in the fuel chamber and increasing air flow to the intake manifold.