| 摘要 |
PROBLEM TO BE SOLVED: To allow an existing diesel engine vehicle using light oil fuel to travel as a diesel engine vehicle using DME fuel in a easy and extremely low-cost manner, without replacing the entire diesel engine. SOLUTION: A tip portion 21 of a needle valve 2 is formed by a center diameter L3 that defines minimum passage area during full lifting of a fuel injection nozzle 1, a seat diameter L2 of a seat portion 211 that abuts on a valve seat portion 33 and cuts off communication with a fuel injection hole 31, and a shaft diameter L1, and has approximately 92° of a tip angle. The center diameter L3, the seat diameter L2 and the shaft diameter L1 are set to be 2.5 mm, 3.0 mm and 3.25 mm, respectively. The ratio of the center diameter L3 to the seat diameter L2 is L3/L2 = 2.5 mm/3.0 mm = approximately 0.833; that of the seat diameter L2 to the shaft diameter L1 is L2/L1 = 3.0 mm/3.25 mm = approximately 0.92. COPYRIGHT: (C)2004,JPO
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