Evaporative emissions control system including a charcoal canister for small internal combustion engines

An internal combustion engine operable at low and high speeds, comprising:

• a carburetor, comprising:
• a passage through which engine intake air is drawn, said passage having an inlet and an outlet;
• a throttle valve disposed within said passage, said throttle valve movable between a substantially closed position corresponding to low engine speeds and a substantially open position corresponding to high engine speeds;
• and
• a fuel chamber in fluid communication with said passage, said fuel chamber containing a volume of liquid fuel and an air space;
• a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space;
• and
• a fuel vapor control device including a housing containing fuel vapor absorbent media, said housing in fluid communication with at least one of said carburetor air space and said fuel tank air space, and in fluid communication with said carburetor passage at a first location proximate said throttle valve and at a second location proximate said inlet;
• whereby fuel vapors collect within said fuel vapor absorbent media of said housing, and at low engine speeds, airflow through said carburetor passage with substantial closure of said throttle valve induces purging of fuel vapors from said housing in a direction from said second location to said first location, and at high engine speeds, airflow through said carburetor passage with substantial opening of said throttle valve induces purging of fuel vapors from said housing in a direction from said first location to said second location.

An internal combustion engine, comprising:

• a carburetor having an intake air passage, and a fuel chamber in fluid communication with said passage, said chamber containing a volume of liquid fuel and an air space;
• a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space;
• and
• a fuel tank cap attached to said fuel tank and containing fuel vapor absorbent media, said fuel tank cap in fluid communication with said carburetor passage, the atmosphere, and with said fuel tank air space and said carburetor air space;
• whereby fuel vapors collect within said fuel vapor absorbent media, and passage of air through said carburetor passage induces a flow of air from the atmosphere through said fuel tank cap to said carburetor passage to purge fuel vapors from said fuel tank cap.

An internal combustion engine, comprising:

• a carburetor having an intake air passage, and a fuel chamber in fluid communication with said passage, said chamber containing a volume of liquid fuel and an air space;
• a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space;
• and
• a fuel vapor control device including a housing containing fuel vapor absorbent media, said carburetor air space and said fuel tank air space in fluid communication with said housing, said carburetor passage in fluid communication with said housing and said housing further in fluid communication with the atmosphere;
• and
• a gravity-responsive valve disposed between said fuel tank air space and said fuel vapor control device;
• whereby fuel vapors collect within said fuel vapor absorbent media, and passage of air through said carburetor passage induces a flow of air from the atmosphere through said housing to said carburetor passage to purge fuel vapors from said housing.

An internal combustion engine, comprising:

• a fuel tank including a filler neck, said fuel tank containing a volume of liquid fuel and an air space;
• and
• a fuel tank cap attached to said filler neck of said fuel tank and containing fuel vapor absorbent media, said fuel tank cap in fluid communication with said fuel tank and with the atmosphere, a portion of said fuel tank cap projecting into said filler neck and including liquid fuel blocking structure;
• whereby fuel vapors collect within said fuel vapor absorbent media and liquid fuel from said fuel tank is blocked from contacting said fuel vapor absorbent media by said liquid fuel blocking structure.