| 摘要 |
PURPOSE:To increase pressure while control injection rate with a simple construction by driving a small diameter piston with a large diameter piston until a spill port is sealed, while with fuel pressure in a pressurizing chamber after said port is sealed. CONSTITUTION:A small diameter piston 13 is driven by a large diameter piston 12 which is moved to a pressurizing chamber 14b side due to the application of a pressurized fuel from a fuel injection pump, to pressurize fuel in a high pressure chamber 16 and feed it to a fuel injection valve 7, carrying out fuel injection. In this case, since a fuel feeding rate is reduced by the ratio of the sectional area of the large diameter piston 12 to that of the small diameter piston 13, the fuel injection rate is reduced. As the pressurized fuel is further added until a spill port 26 is sealed by the peripheral edge part of the large diameter piston 12, the fuel in the pressurizing chamber 14b is pressurized by the large diameter piston 12. Thereby, fuel injection is carried out by the fuel in the high pressure chamber 16 which is pressurized by the small diameter piston 13 which is driven while being separated from the large diameter piston 12. Since the fuel feeding rate is larger in this case, the fuel injection rate is also increased.
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