Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Reexamination Certificate
1999-09-13
2001-09-18
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
Reexamination Certificate
active
06290148
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a fuel injection valve and a method for setting a predeterminable damping stroke of a fuel injection valve.
In a common rail injection system, before the main injection a preinjection (pilot injection) is made, in order to achieve gentler combustion in the combustion chamber of the internal combustion engine and thus reduce the noise output by the engine. The fuel quantity dispensed into the combustion chamber in the pilot injection is smaller than the fuel quantity in the main injection. In known fuel injection valves, the opening of the injection valve is delayed in order to attain small injection quantities.
From German Patent Disclosure DE 43 40 305 A1, a fuel injection valve is known in which during the valve opening, a defined volume is positively displaced into an annular chamber, and this volume is diverted via a throttle and the valve opening is thus delayed in a defined manner.
From Japanese Patent Disclosure 10122078 A, an injector is known in which a nozzle needle is axially displaceably disposed in the guide bore of a nozzle body and opens with a delay, after the valve opening, up to a predetermined damping stroke. On its upper end, the nozzle needle has a cylindrical shaft, which in turn is subdivided by a shoulder into an upper shaft part of larger diameter and a lower shaft part of smaller diameter. The shaft is disposed axially displaceably in the damping bore of a damping unit. If the deflection of the nozzle needle exceeds the damping stroke, then fuel flows out through the annular gap that is formed by the lower shaft part and the damping bore. The nozzle needle and the shaft are embodied in one piece, comprising a single body.
SUMMARY OF THE INVENTION
The object of the invention to furnish a fuel injection valve in which the valve opening of a fuel injection valve is delayed by means that are simple to produce.
In the invention, upon valve opening, the fuel is compressed in a damping chamber and a compression chamber communicating with the damping chamber, so that a damping force that delays the valve opening acts on the nozzle needle. The damping body is operatively connected to the nozzle needle, and as a function of its position in the nozzle bore it opens up a communication between the damping chamber and the outflow chamber.
The damping body and the nozzle needle are two separate bodies, so that a force oriented radially to their axis, caused for instance by displacement toward one another of the injector bodies that guide the damping body and the nozzle needle, does not lead to shear forces or bending forces on the damping body and/or the nozzle needle.
The damping body is also guided in the damping bore over at least a substantial part of the length of the damping body and/or of the damping bore, and preferably over the entire length of the damping bore, so that canting of the damping body in the damping bore is averted. The annular gap between the damping body and the damping bore can be made so narrow that even given its slight axial length, which at maximum is as long as the damping stroke, it has a sealing effect.
To produce the fuel injection valve and to set the damping stroke, the fuel pressure in the fuel conduit and in the outflow chamber is first measured in a test setup, and from that, a conclusion is drawn about the damping stroke or the total stroke; the damping stroke in the fuel injection valve is then set. Production variations in the damping stroke are advantageously compensated for by the insertion of a compensation disk, whose thickness is selected as a function of the measured damping stroke.
Preferred exemplary embodiments of the invention are described in further detail below in conjunction with the drawings, in which:
REFERENCES:
patent: 4531676 (1985-07-01), Seifert et al.
patent: 4684067 (1987-08-01), Cotter et al.
patent: 4911366 (1990-03-01), Priesner
patent: 5205492 (1993-04-01), Khinchuk
patent: 5267694 (1993-12-01), Frank et al.
patent: 5727738 (1998-03-01), Hofmann et al.
patent: 3839812 (1968-04-01), None
patent: 3041018 (1982-05-01), None
patent: 3344723 (1984-06-01), None
patent: 88 09 257 (1989-12-01), None
patent: 3900763 (1990-07-01), None
patent: 4126698 (1992-10-01), None
patent: 4340305 (1995-06-01), None
patent: 1110102 (1968-04-01), None
patent: 2086473 (1982-05-01), None
patent: 10-122078 (1998-05-01), None
Frank Wilhelm
Rizk Reda
Greenberg Laurence A.
Lerner Herbert L.
Morris Lesley D.
Siemens Aktiengesellschaft
Stemer Werner H.
LandOfFree
Device for delaying the deflection of the nozzle needle of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for delaying the deflection of the nozzle needle of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for delaying the deflection of the nozzle needle of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2548256