Fuel injection valve

摘要

An air fuel mixing portion 5A in an air fuel assist type fuel injection valve comprises a cylindrical upstream portion 5a including an air injection opening 3, and a cylindrical downstream portion 5b whereby dripping of fuel can be minimized. A spray angle of 30 DEG or less is obtainable, and a rate of change in fuel flow between an air-injection time and a non-air-injection time can be reduced. Further, the relation between the diameter D1 of the upstream portion and the diameter D2 of the downstream portion is determined to be D1<D2.