Metering valve for controlling the shutter of a fuel injector
AssigneeElasis Sistema Ricerca Fiat Nel Mezzogiorno Societa Consortile per Azioni
InventorsSisto De Matthaeis, Mario Ricco
Life of this patent
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Abstract
A metering valve has a valve body with a control chamber, a pressurized f supply conduit and a fuel drain conduit. A control rod of a shutter includes an element for hydraulically affecting the fuel supply conduit and the fuel drain conduit so that fuel drainage is considerably reduced. The control rod slides in a first cylindrical portion of the control chamber. A second portion of the control chamber that is coaxial with the first portion forms an annular shoulder against which the element is arrested. The fuel supply conduit is located radially of the first portion, and the fuel drain conduit is located axially of the second portion of the control chamber.
Claims5
A metering valve for controlling the shutter of a fuel injector, comprising:
- a body (56);
- a control chamber (61) provided in said body (56), said chamber (61) comprising a first cylidrical portion (71) provided with a supply conduit for feeding pressurized fuel into said chamber (61), and a second portion (72) provided with a drain conduit (63) for draining fuel form said chamber (61),
- said body (56) comprising a shoulder (73) disposed within said chamber (61) and located on a plane separating said first portion (71) from said second portion (72),
- a cylindrical rod (8) sliding into said first portion (71);
- and
- an element (74) integral with an end of said rod movably disposed within said chamber (61) for arresting against said shoulder (73) so as to hydraulically separate said portions (71, 72) and to cut off communication between said supply conduit (62) and said drain conduit (63),
- whereby the fuel drainage from said chamber (61) is reduced, the time required to re-activate said shutter (28) is limited to that required for pressurizing said second portion (72) and pressure in said portion (71) risen as said element (74) approaches said shoulder (73) to exert a braking effect on said rod (8) for reducing end-of-travel impact of said rod (8) and consequent wear of said element (74) and said shoulder (73).
Dependencies are inferred from the claim text.