초록 ▼

A pintle nozzle, preferably an unthrottled pintle nozzle, is provided in which a negative interference angle is formed between the conical tip of the nozzle needle and the mating conical valve seat so that the needle seat is located at the bottom of the valve seat rather than at the top. The resulti

A pintle nozzle, preferably an unthrottled pintle nozzle, is provided in which a negative interference angle is formed between the conical tip of the nozzle needle and the mating conical valve seat so that the needle seat is located at the bottom of the valve seat rather than at the top. The resulting nozzle lacks any velocity drop downstream of the needle seat, even at very low needle lifts, so that virtually all of the energy used to pressurize the fuel is converted to kinetic energy. Spray dispersion and penetration at low needle lifts therefore are significantly enhanced. Fuel flow through the converging-diameter discharge passage located between the conical needle tip and conical needle seat also self-centers the nozzle needle at low lifts, thereby helping to assure a symmetric spray and to further enhance spray characteristics. These and other advantages render the nozzle particularly useful for applications which require very small injection quantities such as the injection of fuel into small two-stroke gasoline engines or into pilot-ignited gas-fueled engines.

대표청구항 ▼

[ I claim:] [7.] A bottom seated pintle nozzle comprising:(A) a nozzle body in which is located a valve seat; and(B) a nozzle needle including a needle tip which is selectively 1) seatable on said valve seat at a needle seat and 2) liftable with respect to said valve seat to permit fluid flow past s

[ I claim:] [7.] A bottom seated pintle nozzle comprising:(A) a nozzle body in which is located a valve seat; and(B) a nozzle needle including a needle tip which is selectively 1) seatable on said valve seat at a needle seat and 2) liftable with respect to said valve seat to permit fluid flow past said needle seat and out of said nozzle body, wherein at least a portion of said needle tip has a frusto-conically-shaped peripheral surface that increases continuously in diameter from a lower end thereof to an upper end thereof at an included angle .beta., said angle being between 0.5.degree. and 2.0.degree. less than an included angle .alpha. of said valve seat so that said needle seat is located at a bottom end of said valve seat, whereina seat orifice flow area 1) is formed between said nozzle needle and said needle seat, 2) is normal to a direction of fluid flow past said needle seat, and 3) increases rapidly with needle lift from a value of zero when said nozzle needle assumes its seated position to a maximum value when said nozzle needle assumes a full-lift position, and whereinsaid seat orifice flow area is the smallest flow area through said pintle nozzle at all phases of needle lift so that fluid flow downstream of said seat orifice flow area is always unthrottled.