Patent ID: 7438238

Claim:
An injector for an internal combustion engine, the injector comprising: a nozzle that has an injection hole, through which high-pressure gaseous fuel is injected into a combustion chamber of the engine; a needle that is axially reciprocably received in the nozzle to open and close the injection hole of the nozzle, wherein: the needle includes a sliding portion and a valve portion; the valve portion closes the injection hole when the valve portion engages an inner surface of the nozzle; and the sliding portion and the valve portion are exposed to the high-pressure gaseous fuel; a control chamber for applying a pressure to the needle; a working fluid supply passage for supplying liquid fuel, which serves as a working fluid, to the control chamber; an electric switching valve for controlling an inflow of the liquid fuel to the control chamber and an outflow of the liquid fuel from the control chamber; a high-pressure gaseous fuel supply passage for supplying the high-pressure gaseous fuel to the injection hole; and a lubrication liquid fuel supply passage for supplying the liquid fuel, which serves as a lubrication, from the working fluid supply passage to the sliding portion and the valve portion of the needle, wherein: the sliding portion of the needle includes a glide portion; the nozzle includes a slide hole, which slidably receives the guide portion; the value portion of the needle includes a seating part; the lubrication liquid fuel supply passage, includes: a first lubrication liquid fuel supply passage, which communicates with the working fluid supply passage at a first end, wherein a second end of the first lubrication liquid fuel supply passage opens at the slide hole; and a second lubrication liquid fuel supply passage, which is located inside the needle, wherein: a first end of the second lubrication liquid fuel supply passage opens at the outer peripheral surface of the guide portion to communicate with the first lubrication liquid fuel supply passage; and a second end of the second lubrication liquid fuel supply passage opens at an upstream side of the seating part of the needle; and wherein the second lubrication liquid fuel supply passage is constructed such that the first end of the second lubrication liquid fuel supply passage is communicated and discommunicated relative to the first lubrication liquid fuel supply passage through opening and closing the injection hole by the needle.