US 4,088,715 AGranted

Variable venturi carburetor

OwnerClinton L. Graybillinventor

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Abstract

A variable venturi carburetor is described that functions in relation to an internal combustion engine to deliver a homogenous mixture of hydrocarbon fuel and air to the engine cylinders in response to vacuum pressure created through the cylinders. The carburetor includes axially movable venturi members for effectively changing the air volume entering through the primary air duct. Provision is made for maintaining a preselected volume of raw fuel available in a reservoir for instantaneous delivery in response to demand created through various throttle opening conditions. In addition to this feature, I provide mechanism by which the air-fuel ratio is appropriately adjusted automatically in response to changing throttle positions. This is done by changing the "head" or distance from the fuel reservoir level to the fuel outlet orifice, thereby changing the pressure requirements for drawing the fuel from the reservoir to the outlet orifice. A further provision is made in the form of a barometric sensing device that is operatively connected to the carburetor in order to automatically vary the air-fuel ratio in response to varying air pressure conditions at various altitudes.

Claims34

Dependent claims

A variable venturi carburetor for an internal combustion engine, comprising:

a hollow body defining a longitudinal open air duct leading from an open intake end to an open discharge end;
a first annular venturi surface in the duct;
a second annular surface in the duct coaxial to the first venturi surface with the venturi surfaces forming an annular restricted air passage therebetween within the air duct;
throttle means operatively connected to at least one of the venturi surfaces for axially moving the venturi surfaces relative to each other to increase or decrease the cross section of the annular restricted air passage;
fuel reservoir means for receiving and storing a volume of liquid fuel therein at a preselected liquid level;
said fuel reservoir means having a plurality of independent fuel wells angularly situated about the duct;
an annular fuel outlet orifice formed in one of the venturi surfaces coaxial with the air duct and openly communicating with the restricted air passage;
a plurality of upright fuel suction tubes projecting downwardly into respective fuel wells for receiving fuel therefrom and for delivering the fuel to the annular outlet orifice at angularly spaced locations;
and
fuel mixture control means operatively connected between the reservoir means and the tubes and responsive to the movement of the venturi surfaces relative to each other for varying the effective distance between the liquid level and the annular fuel outlet orifice to thereby vary the amount of fuel delivered to the annular fuel outlet orifice.

7 more elements

A variable venturi carburetor for an internal combustion engine, comprising:

a hollow body defining a longitudinal open air duct leading from an open intake end to an open discharge end;
a first venturi member formed by an interior wall of the air duct;
a first annular fuel outlet orifice formed in the first venturi member in open communication with the air duct;
a second venturi member coaxially located within the air duct;
a second annular fuel outlet orifice formed in the second venturi member in open communication with the air duct;
throttle means for selectively moving the first and second venturi members axially relative to one another to thereby control the velocity and volume of air passing through the duct;
a first fuel means operatively connected to the first annular fuel outlet orifice for delivering fuel to the first annular outlet orifice;
a second fuel means operatively connected to the second annular outlet orifice;
wherein the first and second means includes a first and second reservoir means respectively for receiving and maintaining liquid fuel therein at a preselected level;
wherein the first and second fuel means includes fuel suction tube means leading from the associated first and second outlet orifices to the reservoir means for receiving and delivering fuel to the first and second outlet orifices;
wherein the first reservoir is formed of a plurality of independent fuel wells situated about the body and wherein the suction tube means includes an upright suction tube extending into each well.

8 more elements

Dependencies are inferred from the claim text.