Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Reexamination Certificate
1999-11-10
2001-05-22
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
C239S088000, C123S470000
Reexamination Certificate
active
06234413
ABSTRACT:
This invention relates to an injector assembly comprising an injector and a wall having an inner surface defining a cavity receiving the injector. The invention also relates to an injector for fitting in a cavity. The invention is applicable particularly, but not exclusively, to fuel injectors and injector assemblies for internal combustion engines.
In a known type of fuel injector assembly, an injector having an axially extending portion of substantially circular cross-section is closely fitted in a cavity within a cylinder head, the cavity having an inner surface of correspondingly circular cross-section. A connector feeds fuel from a high pressure line into a fuel passageway in the injector. The passageway's inlet opens to the lateral periphery of the axially extending portion of the injector. When the connector is tightly fitted so as to seal against the inlet, lateral force is exerted on the injector. The lateral force causes an equal and opposite reaction force where the substantially concentric surfaces of the injector and cavity meet, in a region diametrically opposite the injector inlet.
Whilst such assemblies have hitherto provided acceptable performance at commonly used levels of fuel pressure, a problem has arisen with such assemblies due to stress concentrations within the injector at a region of intersection of a generally laterally extending drilling and a generally axially extending drilling which together form the fuel passageway. The problem is exacerbated when increased fuel injection pressures are used. Such stress concentrations tend to produce tensile forces acting substantially perpendicularly to the applied force, outwardly of the injector, which may limit the pressure which the injector is able to withstand.
The invention seeks to overcome or mitigate the above-mentioned problem.
SUMMARY OF THE INVENTION
Accordingly, the invention provides an injector assembly comprising an injector and a wall having an inner surface defining a cavity receiving the injector, a peripheral surface portion of the injector and a corresponding portion of the cavity inner surface being configured to inter-engage such that force applied to the injector in a predetermined direction causes mutually oppositely directed reaction forces perpendicular to the applied force which tend to laterally compress the injector, for relieving lateral stress within the injector. This can conveniently be achieved by providing a space between the wall's inner surface and a region of the peripheral surface portion of the injector lying opposite a point of application of the applied force.
The injector and cavity are preferably configured such that reaction forces having two mutually equal and opposite components are caused perpendicular to the applied force.
Where the injector includes a passageway for carrying high pressure fluid leading from the lateral periphery of the injector to an axial end of the injector, the applied force being applied laterally by a connector supplying fluid to the passageway, and the passageway comprises a primarily laterally extending portion and a primarily axially extending portion, the injector and cavity surfaces may conveniently be arranged to direct the mutually opposite reaction forces through a region of the injector where the passageway portions intersect.
Advantageously, an axially extending portion of the injector which includes the above-mentioned peripheral surface portion thereof is part circular in lateral cross-section. Preferably, this axially extending portion is configured such that the part circular portion of its periphery would provide a close matching fit with the substantially circular corresponding portion of the cavity inner surface, but for a relieved segment of the axially extending portion having an eccentrically disposed peripheral curve with a larger radius of curvature, thereby providing two regions of inter-engagement of the injector and the cavity inner surface for respectively providing the reaction forces.
Alternatively, the injector may comprise an axially extending portion which is substantially circular in lateral cross-section, two irregularities extending radially inwardly from the cavity inner surface, which is otherwise correspondingly circular in cross-section, thereby providing two regions of inter-engagement between the injector and the cavity inner surface for respectively providing the reaction forces.
The connector conveniently applies lateral force in a direction along the primarily laterally extending portion of the passageway midway between the regions of engagement, thereby bisecting the injector.
The wall may comprise a body portion having a bore receiving a sleeve, the inner surface of which defines said cavity.
The invention also includes an injector for fitting in a cavity, the injector having an axially extending portion comprising at least two peripheral irregularities in an otherwise substantially regular lateral cross-section. The axially extending portion may be part circular in lateral cross-section, one segment of this portion having an eccentrically disposed peripheral curve with a large radius of curvature, thereby providing two peripheral irregularities for engaging a cavity inner surface having a substantially circular cross-section.
In order that the invention may be well understood, an example thereof, which is given by way of example only, will now be described with reference to the accompanying drawings, in which:
REFERENCES:
patent: 3845748 (1974-11-01), Eisenberg
patent: 4365756 (1982-12-01), Fisher
patent: 5365907 (1994-11-01), Dietrich et al.
patent: 5617828 (1997-04-01), Kuegel et al.
patent: 5775303 (1998-07-01), Sweetland et al.
patent: 4140668 (1992-07-01), None
patent: 4319269 (1994-12-01), None
patent: 569727 (1993-11-01), None
patent: 210359 (1983-12-01), None
Lucas Industries Limited
Nguyen Dinh Q.
Ohlandt Greeley Ruggiero & Perle L.L.P.
Scherbel David A.
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