US 5,853,124 AGranted

Bottom seated pintle nozzle

AssigneeServojet Products International

InventorsNiels John Beck, William P. Johnson, Kresimir Gebert, Hoi Ching Wong

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Abstract

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.

Claims15

Dependent claims

A bottom seated unthrottled pintle nozzle comprising:

(A) a nozzle body having a frusto-conically-shaped valve seat formed therein that increases continuously in diameter from a lower seat orifice thereof to an upper end thereof at an included angle of .alpha.;
and
(B) a nozzle needle movable substantially axially with respect to said valve seat, said nozzle needle including a lower needle tip movable 1) from a lowered, seated position in which said needle tip seats against said valve seat at a needle seat so as to prevent fluid flow through said nozzle 2) to a lifted position in which said needle tip is spaced from said valve seat to permit fluid to flow through a discharge passage formed between said needle tip and said valve seat, past said needle seat, and out of said seat orifice, 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 said angle .alpha. so that said needle seat is located at a bottom end of said valve seat, wherein
a 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 wherein
said 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.

3 more elements

A method of injecting a liquid from a nozzle comprising:

(A) providing a nozzle having 1) a nozzle needle including a lower needle tip and 2) a nozzle body having a valve seat located therein which receives said needle tip;
(B) seating said needle tip on said valve seat at a needle seat positioned adjacent a seat orifice of said nozzle so as to prevent liquid ejection from said nozzle;
and then
(C) lifting said needle tip from said valve seat to eject liquid from said nozzle by permitting fuel flow from a discharge passage formed between said needle tip and said valve seat, then past said needle seat, and then out of said seat orifice, 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, wherein
a 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 wherein
said 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 is unthrottled so that, during said step (C), said discharge passage decreases continuously in cross sectional area from an upper end of said valve seat towards said needle seat at a designated needle lift, and wherein said fluid 1) flows through said discharge passage at an increasing velocity, 2) flows at a maximum velocity at said needle seat, and 3) is elected from said seat orifice at substantially said maximum velocity.

4 more elements

Dependencies are inferred from the claim text.