| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize favorable atomization of injected fuel by shortening the length of time period where a speed of fuel inflowing to an injection hole and a speed of fuel injection are low. <P>SOLUTION: A fuel injection valve 1 includes a nozzle body 2 and a needle 3. The nozzle body 2 includes a sack chamber 5 located in the downstream end of a fuel flow path 4, a sheet surface 6 located on the upstream side of the sack chamber 5, and an injection hole 7 located on the downstream side of the sheet surface 6. The needle 3 includes a sheet section 8 sitting on the sheet surface 6 when the valve opens, a reduced-diameter section 9 concavely reduced in diameter as going from the sheet section 8 toward the apical end side of the needle 3, and an apical end convex portion 11 continuing from the reduced-diameter section 9 to an apical end to be housed inside the sack chamber 5 when the valve closes and pushes out fuel existing within the sack chamber 5. As a result, when the fuel injection starts, a negative pressure is allowed to occur inside the sack chamber 5 to pull in the fuel and then shorten the rise time of the injection speed. When the fuel injection terminates, a high fuel injection speed is maintained till the fuel within the sack chamber 5 is completely exhausted by the apical end convex portion. <P>COPYRIGHT: (C)2012,JPO&INPIT |
