Fuel break-up disc for injection valve

In a fuel injection valve adapted to be mounted on an internal combustion engine so to be communicated with an intake passage of a combustion chamber thereof comprising:

• fuel outlet means adapted to be communicated with said intake passage and comprising a fuel metering member and a fuel breakup member;
• said fuel metering member comprising a converging inlet surface, a diverging outlet surface, and a metering orifice intermediate said inlet surface and said outlet surface, said metering orifice having a total orifice flow area thereacross for effecting a predetermined flow rate of fuel therethrough;
• and said fuel breakup member comprising a thin disk having an axial thickness not substantially greater than 0.05 mm secured across said diverging outlet surface and comprising a plurality of narrow slots therethrough for breaking said fuel up into uniformly small droplets, said slots having a total slot area thereacross establishing a minimum orifice-to-slot area ratio with said total orifice area of not less than 1.5, said orifice-to-slot area ratio and said 0.05 mm axial thickness of said thin disk cooperating to permit said orifice area to determine substantially the entire magnitude of said predetermined flow rate.