| 摘要 |
PROBLEM TO BE SOLVED: To prevent mixing of a hydraulic fluid in an air chamber for introduc ing an air-fuel mixture, and mixing of air in an operating force chamber for introducing the hydraulic fluid, in a fuel injector for injecting the air-fuel mix ture of fuel an air by driving a needle valve by pressure of the hydraulic fluid. SOLUTION: The operating force chamber 14 and the air chamber 15 cut off by a fitting clearance are formed by fitting a diametrally expansive part 13a of the needle valve 13 to the inner periphery of a nozzle 12. A groove 41 is formed on the whole periphery in the diametrally expansive part 13a. This groove 41 and a communicating passage 42 formed in the needle valve 13 are connected by a horizontal hole 43. The fuel and the air leaking into the fitting clearance are introduced into a gas-liquid separating chamber 45 via the grove 41, the horizontal hole 43, and the communicating passage 42. The air obtained by gas-liquid separation is supplied to an intake air passage 33 on the upstream side of a throttle valve 32, and the fuel is supplied to a canister 30.
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