| 摘要 |
PURPOSE:To provide a constant difference between pressures upstream and downstream of a fuel needle valve and to feed a suitable fuel amount under all operating conditions, by installing a fuel pressure regulator between the fuel needle valve and a fuel pump. CONSTITUTION:When the velocity of flow of the air flowing in a small Venturi 10a is high during operation at a low speed, the pressure of the air chamber 34 of a fuel pressure regulator 30 is reduced through an air passage 36, and the fuel returns to a fuel tank 14 after passing the gap between a surplus fuel return passage 38 and a valve 35, whereby the fuel upstream of a needle valve 16 is reduced in its pressure. In this case, the pressure in a nozzle 10b is also decreased, and thereby both fuel pressures upstream and downstream of the fuel needle valve 16 are reduced. When an operating speed increases, the inside of the small Venturi 10a stays at the atmospheric pressure and relatively high fuel pressure is generated upstream of the fuel needle valve 16. This brings both upstream side and downstream side in a pressure rising state. |
