| 摘要 |
A unit injector comprising a plunger, a high pressure fuel chamber, and a needle; the pressure of fuel in the high pressure fuel chamber being increased by the plunger. A spill valve is slidably inserted into a bore and is actuated by an actuator. The spill valve has a first annular fitting portion in tight contact with the inner wall of the bore at one end thereof, and has a second annular fitting portion in tight contact with the inner wall of the bore at the other end thereof. The bore has an annular valve seat formed on the wall thereof, and the spill valve has an annular valve portion between the first annular fitting portion and the second annular fitting portion. A high pressure fuel introduction chamber is formed around the spill valve between the first annular fitting portion and the annular valve portion and is continuously connected to the high pressure fuel chamber. A fuel spill chamber is formed around the spill valve between the second annular fitting portion and the annular valve portion, and when the annular valve portion is moved away from the annular valve seat, fuel under a high pressure is spilled out from the high pressure fuel chamber into the fuel spill and the fuel injection is stopped.
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