Carburetor for use in internal combustion engine

摘要

A carbureter for use in an internal combustion engine wherein a rotary throttle valve provided therethrough in the radial direction of the rotary shaft with a gasified fuel-air mixture passageway is provided in an air supply duct of the carburetor and the flow of mixtures of gasified fuel and air that is supplied into the engine can be controlled by the rotation of said rotary throttle valve, while said rotary throttle valve stays at a low opening degree, a bypass passageway forking from the intermediate portion of a low speed fuel passageway is made open to said gasified fuel-air mixture passageway and at the same time the upstream portion of the air supply duct of said rotary throttle valve and said gasified fuel-air mixture passageway can be communicated through an air passageway and while said rotary throttle valve is moved from the position "close" toward "open," predetermined interrelations are given to the opening positions or the sizes of port diameters of said gasified fuel-air mixture passageway, of said air passageway and of said bypass passageway, so that the flow of the mixtures of gasified fuel and air can be smoothly increased from a lower speed to a higher speed.