Perfected electromagnetic metering valve for a fuel injector
AssigneeElasis Sistema Ricerca Fiat Nel Mezzogiorno Societa Consortile per Azioni
InventorMario Ricco
Life of this patent
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Abstract
The metering valve has a shutter for a discharge conduit, and an electromagnet for controlling an armature disconnected from the respective stem and sliding along the stem by means of a sleeve. The stem is guided by a fixed sleeve and is pushed by a first spring to hold the shutter in the closed position, and a second spring keeps a shoulder of the armature resting axially against a C-shaped ring fitted to the stem. To reduce the overtravel of the armature with respect to the travel of the stem to move the shutter into the closed position, and to damp oscillation of the armature, provision is made, between the two sleeves, for a bush of calibrated thickness, which slides along the stem and is such as to form a small axial clearance with the sleeves.
Claims9
An electromagnetic metering valve for a fuel injector, comprising a shutter (44) for a discharge conduit (43) of a control chamber (41);
- an electromagnet (26) for activating an armature (27) to control said shutter (44) via an intermediate element (47);
- and a first spring (52) acting on said intermediate element (47) to keep said shutter (44) in a closed position;
- said armature (27) being disconnected from said intermediate element (47), and being held in an idle position resting against the intermediate element (47) by a second spring (61);
- characterized in that stop means (62) are provided for arresting the movement of said armature (27) produced by said first spring (52) said stop means (62) being independent of said shutter (44), and being so arranged as to reduce the overtravel of said armature (27) with respect to the travel of said intermediate element (47), permit rapid return of said armature (27) to said idle position, and damp the rebound of said armature (27) produced by said first spring (52) and said second spring (61).
Dependencies are inferred from the claim text.