Fuel injection valve

A fuel injector for direct injection of fuel into a combustion chamber of an internal combustion engine, comprising:

• an energizable actuator;
• a valve needle in operative connection with the energizable actuator;
• a sealing seat formed by a valve-closure member and a valve-seat surface of a valve-seat member, wherein the valve-seat member includes a plurality of spray-discharge orifices;
• and
• a restoring spring acting on the valve needle in a closing direction to actuate the valve-closure member;
• wherein the pressure of fuel flowing through the fuel injector is greater than 10 bar;
• wherein a diameter of the spray-discharge orifices increases along a discharge direction of the fuel to form a widened region;
• wherein the diameter of the spray-discharge orifices increases in a stepwise manner;
• wherein the ratio of an overall length l of the spray-discharge orifices to a smallest diameter d of the spray-discharge orifices is l≦3d;
• wherein a fractional length l′ of the spray-discharge orifices extending from an inflow side to the widened region is such that the ratio of the fractional length l′ to a smallest diameter d of the spray-discharge orifice is l′≦3d;
• wherein the smallest diameter d is defined by the equation
• d
• =
• (
• 4
• ·
• c
• π
• ·
• n
• ·
• p
• 0.5
• )
• 0.5
• wherein c is a constant, n is the number of the spray-discharge orifices, and p is the pressure of fuel;
• and wherein 0.3≦c≦0.6 [mm2 Mpa0.5].