| 摘要 |
<p>A nozzle for high-pressure mechanical injectors for naval diesel engines, comprising:
- a nozzle body (12) having a longitudinal guide hole (14), a fuel-supply hole (16) coaxial to the longitudinal guide hole (14), a conical valve seat (22) set at one end of said supply hole (16), and a plurality of injection holes (26) communicating with a sac volume (24) that communicates with said supply hole (16) through said valve seat (22); and
- an injection needle (30) having a guide portion (32) slidably engaged in said guide hole (14), and a terminal portion (34), which extends with ample radial play in said supply hole (16), said terminal portion (34) having an end (36) with a sealing seat (38) that co-operates with said valve seat (22),
wherein said guide portion (32) has a guide diameter d g , said conical sealing surface (38) has a sealing diameter d s and a sealing angle ±, and wherein the injection needle (30) has an overall length L and a lift stroke h ,
and wherein:
- the guide diameter d g is comprised between 9.4 and 10.5 mm,
- said sealing needle (30) has a parameter of geometrical stress G defined by the formula G = d g d s �¢ sin / ± 2 �¢ / h L 1 / 4
of a value comprised between 1.00 mm 0.5 and 1.25 mm 0.5 , and
- said end (36) of the terminal portion (34) of the injection needle (30) has a toroidal surface (44) with a radius R comprised between 3 mm and 8 mm set between said conical sealing surface (38) and an internal conical surface (42).</p> |
