| 摘要 |
PROBLEM TO BE SOLVED: To reduce harmful discharged material and prevent operation failure of an outer needle valve by lessening the dead volume of a fuel passage of the outer needle valve in a fuel injection of a double needle valve structure. SOLUTION: An inner needle valve 13 is slidably fitted in an outer needle valve 12 fitted to a nozzle body 11 with the tip projected to the combustion chamber side to form a double needle valve structure. A seat part 17 is formed by the outer peripheral part of the outer needle valve 12 and the inner peripheral part of the nozzle body 11, and a seat part 20 is formed by the tip part of the inner needle valve 13 and the inner tip wall part of the outer needle valve 12. The ratio L/D of the length L of a first nozzle hole 12f to the nozzle hole diameter is set to 2 or more, and the nozzle hole length L of a nozzle hole 12f is set so that the sum of the total waste volume of the nozzle is 1.5 mm3 or less. The outer needle valve 12 and the inner needle valve 13 are lifted to make atomized fuel from the nozzle hole 12f and atomized fuel from the nozzle hole 12g collide with each other.
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