Spark-ignition direct fuel injection valve

A spark-ignition direct fuel injection valve, comprising,

• a seat member provided with a fuel injection hole;
• and
• a valve body which controls fuel injection from the fuel injection hole by selectively contacting and separating from a valve seat,
• wherein the fuel injection hole has a fuel injection hole inlet which is open inwardly of the seat member and a fuel injection hole outlet which is open outwardly of the seat member,
• wherein an opening edge of the fuel injection hole inlet of the fuel injection hole has a round-chamfered portion,
• wherein the seat member has an expanded opening which is expanded in cross sectional area outwardly from the fuel injection hole outlet such that a distance from a front end side of the seat member to a side wall portion on the front end side of the extended opening is a same distance as a distance from an end side opposite to the front-end side to a side wall portion opposite to the front end side of the extended opening,
• wherein a length of the fuel injection hole is longer than a length of the expanded opening in an injection axis direction,
• wherein the cross-sectional area of the fuel injection hole is continuously smaller from the round-chamfered portion of the fuel injection hole inlet to the fuel injection hole outlet,
• wherein a width of the expanded opening in a radial direction is formed larger than a width of an end of the round-chamfered portion,
• wherein the expanded opening expands stepwise outwardly from the fuel injection hole outlet, and has a cross-sectional area of a single rectangle,
• wherein a width of a side of the single rectangle that extends in the radial direction is larger than a width of an outer end of the round-chamfered portion, and
• wherein the fuel injection hole outlet is separated by a distance from a side of the single rectangle that extends perpendicular to the radial direction, and a width of the fuel injection hole outlet is smaller than the distance.