Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Patent
1994-05-02
1995-11-07
Merritt, Karen B.
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
2395335, F02M 4508, F02M 6116
Patent
active
054641586
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a fuel injection nozzle as defined hereinafter. Injection nozzles of this type, by controlling the stroke of the valve needle, have a preinjection and a main injection, in order to reduce the noise of combustion.
In an injection nozzle of this type, known from EP-A 240 683, the valve needle strikes the piston of the pressure transmitting device at the end of the prestroke, and this piston stops the further motion of the valve needle until the fuel pressure has risen far enough that its force exerted upon the valve needle in the opening direction exceeds the force of the closing spring and the force exerted by the piston. Although this known injection nozzle is small in structure, nevertheless the partition, because of the embodiment of the pressure chamber and its connecting conduit, suffers from being complicated to produce.
ADVANTAGES OF THE INVENTION
The fuel injection nozzle according to the invention has the advantage that to attain a graduated opening stroke of the closing needle as far as the piston, the same elements as in a single-spring holder are used; the piston is formed by means of special, but nevertheless easily achieved designing of the pressure bolt that transmits the closing force of the closing spring to the valve needle.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the invention are shown in the drawing and described in detail below. Shown are
FIG. 1, an injection nozzle in longitudinal section;
FIG. 2, a detail A of FIG. 1 on a larger scale, in the closing position of the valve needle on the left and the open position of the valve needle on the right, and
FIG. 3, an alternative to the exemplary embodiment of FIG. 2, again in the closing position of the valve needle on the left and the open position of the valve needle on the right.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
The injection nozzle has a nozzle body 10, which together with a shim 11 is firmly clamped with a union nut 13 to a retaining body 12. A valve needle 15 is displaceably supported in the nozzle body 10 and cooperates with an inwardly facing valve seat 16 in the nozzle body 10, this seat being preceded by a plurality of injection ports 17. The guide bore 18 of the valve needle 15 is widened, as usual, at one point into a pressure chamber 19, in whose region the valve needle 15 has a pressure shoulder 20 and which communicates via a conduit 22 and a filter body 23 with a connection piece 24 on the retaining body 12 for the connection of a fuel line. The fuel engaging the pressure shoulder 20 of the valve needle 15 displaces the valve needle 15 upward, counter to the graduated course of force of a closing force arrangement described hereinafter; the fuel is ejected in a preinjection phase and a main injection phase through the injection ports 17.
A spring chamber 26 for receiving a closing spring 27 is formed in the retaining body 12; the spring is supported at one end on the bottom of the chamber 26, via a disk 28, and at the other end on a pressure piece 29. The pressure piece 29 rests on a piston 30, which is tightly guided in a cylindrical through bore 31 in the shim 11. The piston 30 passes all the way through the through bore 31 and is supported on the valve needle 15, urging it in the closing direction.
The sides facing one another of the piston 30 and the valve needle 15 together with an enlargement 32 of the guide bore 18 in the nozzle body 10, near the shim 11 and a nearby portion of the face of the shim 11, define a pressure chamber 33. A longitudinal groove 35 in the jacket of the piston 30 intermittently connects this pressure chamber 33 with the spring chamber 26, which is pressure-relieved via a leakage conduit 38 and a connection piece 39. Near the side of the piston 30 defining the pressure chamber 33, the longitudinal groove 35 is limited by a control edge 36, which in the closing position of the valve needle 15 and with the piston 30 supported on the valve needle is spaced apart from the annular edge 37 at the transition from
REFERENCES:
patent: 5125580 (1992-06-01), Kronberger
Greigg Edwin E.
Greigg Ronald E.
Merritt Karen B.
Robert & Bosch GmbH
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