Method of producing a fuel injector
AssigneeC.R.F. Societa Consortile per Azioni
InventorsMario Ricco, Adriano Gorgoglione
Life of this patent
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Abstract
A fuel injector has an injector body extending along a given axis; a tubular valve body housed inside a hole in the injector body and coaxial with the injector body; and an annular chamber defined by the injector body and the valve body. The method of producing the injector includes connecting the valve body to the injector body, and fixing the valve body in a given position along the axis with respect to the injector body by means of a driving operation to interference fit the valve body inside the hole in the injector body.
Claims11
In a method of producing a fuel injector, the improvements comprising:
- providing a tubular injector body having an axial seat defined by a cylindrical inner face extending along a given axis;
- providing a tubular valve body housed inside the axial seat in the injector body and coaxial with the injector body, the valve body having a cylindrical lateral wall defined by a cylindrical outer face and a substantially cylindrical seat, the cylindrical lateral wall having an annular groove dividing the cylindrical outer face into two distinct portions for contacting the inner face, the valve body being sealingly fixed to the injector body by an interference fit provided by contacting the two distinct portions of the cylindrical outer face with the cylindrical inner face;
- and
- providing an annular chamber defined by the injector body and the valve body within the interference fit for supplying the fuel from the tubular injector body into the tubular valve body.
In a method of producing a fuel injector comprising a tubular injector body provided with an axial seat defined by a cylindrical inner surface extending along a given axis, and a tubular valve body housed inside the axial seat, the injector body being formed with a hole crosswise to the axis and communicating with a high-pressure fuel supply conduit, the valve body having a cylindrical lateral wall defined by an outer cylindrical surface and a substantially cylindrical seat, the cylindrical lateral wall having an annular groove dividing the outer cylindrical surface into two distinct portions for contacting the inner surface and communicating with the substantially cylindrical seat with a nozzle;
- the improvements of the method comprising:
- grinding the inner surface at a first diameter;
- grinding the outer cylindrical surface at a second diameter greater than the first diameter so as to have a predetermined fitting interference with the inner surface;
- heating the injector body and simultaneously cooling the valve body;
- mutually aligning the lateral wall with the axial seat so as to become coaxial;
- and
- driving the cooled valve body inside the axial seat of the heated injector body to a predetermined axial position with the groove facing the hole,
- wherein the annular groove defines with the inner surface an annular chamber defined by the injector body and the valve body,
- whereby to provide at a normal temperature by contacting the two distinct portions of the outer surface with the cylindrical inner surface an interference fit between the valve body and the injector body that prevents high-pressure fuel leakage from the annular groove.
Dependencies are inferred from the claim text.