| 摘要 |
PURPOSE:To increase the output of an engine by extending the low-speed range of the same and increasing the venturi diameter, by forming an nclined bore portion at a venturi, and opening a plurality of auxiliary sloe ports of an independent, auxiliary low-speed fuel passage in said inclined bore portion. CONSTITUTION:An inclined bore portion 9 is formed between a diverging portion 17 extending from a most coverged portion 16 toward the downstream side of a venturi 3 and a throttle bore 18 where a throttle valve 5 is diposed, and the inclined bore portion 19 is formed with an inclined wall surface 20 which serves to keep the inter space between the marginal portion 5a of the throttle valve 5 located on the side of a slow port 14 and the wall surface 20 constant. Further, an auxi- liary low-speed fuel passage 21 branched from a main fuel passage 8 and constructed in the same structure as a low-speed fuel passage 9 but independently of the same is formed in the body 1 of a carburetor, and a plurality of auxiliary slow ports 22 having a small diameter are opened in said inclined wall surface 20 and connected to an intake pas sage 2. Since, with such an arrange- ment, a high negative pressure in an intake pipe of an engine is applied to the auxiliary slow ports 22 until the throttle valve 5 is closed to an opening losing controllability to the ports 22, desired objects of the inven tion can be adhieved. |
