| 摘要 |
PURPOSE:To prevent idle knocks from occurring by arranging at least two compression sections on a pump plunger and switching the effective cross-sectional area of the compression sections according to revolutions of an engine. CONSTITUTION:Fuel in a fuel passage 15 is drawn into both a small-diametered pressure chamber 61 and an annular pressure chamber 62 by the suction stroke of a plunger 14 and then compressed by the advancement of the plunger 14. Here in the vicinity of an idling revolution, both pressure chambers 61 and 62 are communicated with each other by means of a switch valve 51 due to solenoid excitement to enlarge an effective cross-sectional area of compression sections and two amounts of fuel injections are obtained. At revolutions above the idling on the other hand, the switch valve 51 closes the communication to the small-diametered pressure chamber 61, makes the annular pressure chamber to be communicated with a low-pressured fuel chamber 13 without performing compression, and the small-diametered pressure chamber 61 is compressed by the advancement of the plunger 14 to pressurize the fuel to a high pressure. Thus, in addition to preventing the idle knocks, normal fuel injection can be performed in revolution ranges other than idling.
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