Evaporative emission control apparatus for a combustion engine
AssigneeWalbro Corporation
InventorJohn C. Woody
Life of this patent
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Abstract
A fuel evaporative emission control apparatus in a carburetor which prevents diurnal evaporation to the atmosphere of fuel from a remote fuel tank through a fuel bowl or fuel chamber of a float-type carburetor. One or more shut-off valves in the carburetor are yieldably biased to a shut-off position. Only upon engine operation or user intervention will the fuel shut-off valve move to an open or on position. In this way, reliance upon the engine user is not required to reduce evaporative emissions.
Claims34
An emission control apparatus for a combustion engine having a carburetor, the emission control apparatus comprising:
- a carburetor body having a valve seat;
- a fuel bowl carried by the carburetor body, the fuel bowl defining a fuel chamber;
- a fuel-in passage defined by the carburetor body, the fuel-in passage extending between an external carburetor fuel inlet and an inlet aperture defined by the valve seat;
- a fuel-out passage defined by the carburetor body, the fuel-out passage communicating with the fuel chamber;
- a float valve disposed within the fuel chamber, the float valve constructed and arranged to close the fuel-out passage when the fuel chamber contains sufficient fuel and to open the fuel-out passage when the fuel chamber contains insufficient fuel;
- a recess defined by the valve seat, the inlet aperture and the outlet aperture each communicating with the recess;
- and
- a valve head disposed in the recess, the head having an on position and an off position, wherein the inlet aperture is in communication with the outlet aperture via the recess when the head is in the on position, and wherein the inlet aperture is obstructed by the head from being in communication with the outlet aperture when the head is in the off position.
An emission control apparatus for an internal combustion engine having a carburetor, the emission control apparatus comprising:
- a carburetor body having a recess, a fuel inlet aperture, a fuel outlet aperture and each aperture communicating with the recess;
- a fuel chamber carried by the carburetor body, the fuel chamber being exposed to atmospheric pressure;
- a lid covering the recess and carried by the carburetor body;
- a valve head disposed rotatably in the recess about a centerline and having an on position and an off position, the head having an arm projecting radially outward beyond the recess and through a circumferential slot in the carburetor body, the arm being constructed and arranged to move between opposite ends of the slot thereby positioning the valve head in either the on or off position;
- an external fuel tank at near atmospheric pressure and being elevated above the fuel chamber;
- a fuel-in passage defined by the carburetor body and communicating between the external fuel tank and the recess through the fuel inlet aperture;
- a fuel-out passage defined by the carburetor body and communicating between the fuel chamber and the recess through the outlet aperture;
- the inlet aperture communicating with the outlet aperture when the valve head is in the on position and the inlet aperture not communicating with the outlet aperture when the valve head is in the off position;
- and
- a push pull cable connected to a distal end of the arm to move the valve head to the on and off position.
Dependencies are inferred from the claim text.