JPS5546013A - Accelerating fuel supply system in carburettor - Google Patents

Abstract

PURPOSE: To always maintain gas exhausting performance of an engine in a good condition by providing same with an accelerating fuel supply system in a carburettor thereof which is operable to supplementally supply an optimum amount of fuel for an appropriate period of time in accordance with accelerating conditions of the engine so as to compensate for fuel air ratio during acceleration of the engine.

CONSTITUTION: If a throttle valve 7 is opened, for example, to a B position in order to accelerate an engine from its stationary state, suction negative pressure acting at a negative pressure extracting port 27 is decreased. This change of negative pressure is transmitted to chambers 22 and 23 of a negative pressure responsive valve 20 through conduits 28 and 29, respectively, whereupon negative pressure is decreased instantaneously in the chamber 23 while negative pressure is gradually decreased in the chamber 22 due to the existence of a throttle 30 so that a diaphragm 24 is moved leftwardly against the urging of a spring 26. As a result, a valve body 25 of the valve 20 is moved leftwardly to open an accelerating fuel supply passage 12. Meanwhile, negative pressure is allowed to act upon ports 14a, 14b. Accordingly, accelerating fuel is sucked into a suction bore 2 from a float chamber 4 through the passage 12 and the ports 14a, 14b while the valve body 25 is held to the position for allowing the passage 12 to be opened.

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