Fuel injection nozzle for internal combustion engine

摘要

The nozzle is used in a common rail injection system and has a needle (11) moved by an actuating device. The needle has a sharp tip (121) extending into a small chamber (110) from which the fuel flows through spray nozzle passages (120). Fuel from the supply flows into a conical portion of the nozzle with a first taper angle (alpha1) of 60 degrees. The needle has a conical portion leading into a portion with a gentle taper (alpha3) of 30-40 degrees followed by a more sharply tapered portion (alpha2) of 58.5 degrees which seals against the tapered bore of the nozzle. There is a groove (19) in the tip, immediately downstream of the sealing portion, facing a matching groove (18) in the bore of the nozzle. A tapering annular chamber (17) leads into the tip chamber.