| 摘要 |
PURPOSE:To prevent the performance of a fuel injection valve from being deteriorated due to the mixing of hydraulic fluid and fuel fed respectively into primary and secondary chambers, by constituting a pressure boost mechanism coupled to a plunger for feeding fuel into a nozzle from a high pressure chamber, with bellows so that the primary and the secondary chambers are separately formed. CONSTITUTION:A pressure boost mechanism coupled to a plunger 7 for feeding fuel into a nozzle 1 from a high pressure chamber 9 is composed of bellows 29 which are held by a clamping member 30 between a holder 3 and a unit body 12 so that the inside of the clamping member 30 is divided into a primary chamber 32 and a secondary chamber 33. Further, the primary chamber 32 is connected to a communication passage 28 between valve seats 25, 26 through a working fluid suction and discharge passage 34 formed in the unit body 12 and a stator 19 so that working fluid may be fed into the primary chamber 32. Meanwhile, fuel leaking from the high pressure chamber 9 is fed into the secondary chamber 33, and is, therefore, returned into a low pressure side fuel inlet passage 10 through a fuel overflow passage 35 formed in the holder 3. With this arrangement, it is possible to completely separate working fluid from fuel. |
