Carburetor with fuel shut-off means having a fuel-air ratio adjustment mechanism

Claim 1

For a spark-ignition internal combustion engine carburetor having an air-fuel conduit and a throttle valve positioned therein, a fuel-to-air ratio regulating means, comprising, a. a fuel discharge member including an elongated, generally tubular bar extending normally with respect to the longitudinal axis of said air-fuel conduit and having fuel discharge orifice means formed therethrough disposed downstream of said tHrottle valve providing communication between the interior of said tubular bar and said conduit downstream of said throttle valve, substantially all of the liquid fuel required by the engine to said conduit being introduced through said discharge orifice means; b. a movable element associated with said tubular bar and cooperable with said fuel discharge orifice means, the effective cross sectional area of said orifice means being directly dependent upon the position of said movable element with respect to said tubular bar and continually varying in accordance with movement of the movable element with respect to said tubular bar, said movable element being movable between a closed position wherein communication between the interior of said tubular bar and said conduit is precluded and fully open position wherein a pre-established effective cross sectional area of said discharge orifice means affords maximum communication for the flow of liquid fuel between the interior of said tubular bar and said conduit; c. biasing means yieldably urging said movable element in one direction toward its fully open position; d. stop means operatively engageable with said movable element to limit movement of said movable element in said one direction and thereby establish the fully open position of said movable element; and e. actuating means for moving said movable element toward its fully closed position against the resilient action of said biasing means, said actuating means being responsive to the absolute pressure value in said conduit downstream of said throttle valve and being effective to rapidly move said movable element to its closed position and to maintain such closed position when said absolute pressure value in said conduit downstream of said throttle valve is below a predetermined value, said biasing means being effective to rapidly move said movable element in said one direction and into operative engagement with said stop means when the absolute pressure value in said conduit downstream of said throttle valve rises to a value at least equal to said predetermined value.