Variable venturi carburetor
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorsNorihiko Nakamura, Takashi Kato
Life of this patent
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Abstract
A variable venturi carburetor in which a biasing spring urges a metering needle to contact the metering jet during low air-intake operating conditions and including an expanded portion formed at the front end of the metering needle which is loosely contained in a large bore portion of a well during low air-intake operating conditions and which engages a small bore portion of the well during high air intake operating conditions to center the metering needle in the metering jet for maintaining bleed sensitivity constant while the amount of bleed air varies.
Claims9
A variable venturi carburetor comprising:
- a suction chamber provided to one side of the venturi;
- a suction piston slidably inserted in the suction chamber;
- a biasing spring installed in a needle holder provided in the suction piston head;
- a metering needle held and biased by the biasing spring in the needle holder, the metering needle being loosely inserted through a main nozzle adapted to pass fuel and bleed air provided in the other side of the venturi opposite to the suction piston and through the metering jet adjacent to the main nozzle in such a manner that the needle can be brought into contact with the metering jet;
- a well into and from which the front end of the metering needle is made to advance or retract, the well having a large-bore portion and a small-bore portion;
- and an expanded portion formed at the front end of the metering needle, the expanded portion being sized so that it engages with the small-bore portion when the needle is retracted and is loosely contained in the large-bore portion when advanced;
- whereby during the low air-intake operating condition the metering needle is urged by the biasing spring to press against the metering jet and during the high air-intake operating condition it is floated centered in the metering jet, thus controlling the quantity of bleed air.
Dependencies are inferred from the claim text.