| 摘要 |
PURPOSE:To prevent an engine from increasing its r.p.m. at the full closure of throttle valve, by restricting an intake negative pressure to be withdrawn into a negative pressure actuating device with the increase of throttle valve opening amount, in the engine adapted to regulate the opening amount of throttle valve by balancing the tension of governor spring with the actuating force of negative pressure actuating device. CONSTITUTION:A governor spring 6 and a negative pressure actuating device 7 are provided to a throttle lever 5 manipulating the throttle valve 4 of carburetor 2. The spring 6 has its base end part 6a connected with a manually operable speed setting lever 27 for urging the throttle valve 4 in the opening direction. The negative pressure actuating device 7 attracts a diaphragm 12 in opposition against a return spring 13, utilizing an intake negative pressure to be withdrawn into a negative pressure actuating chamber 11 via a communicating passage 15, and consequently closes the throttle valve 4 through a manipulation arm 14. A negative pressure regulating valve 17 is interposed in the midway of communicating passage 15, the valve 17 being constituted so as to push a valve body 21 via a link 18 and a cam 19 in opposition against a return spring 22 for thereby regulating the flow rate of air, when the throttle lever 5 is manipulated in the opening direction of valve 17. |
