Double-switching valve for fuel injection system
AssigneeRobert Bosch GmbH
InventorStefan Schempp
Life of this patent
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Abstract
The invention relates to a unit injector for injecting fuel into the combustion chamber of a self-igniting internal combustion engine, including a pump part a nozzle part and an final control element that is followed downstream by a hydraulic coupler which actuates a valve needle of a 2/2-way valve inside a nozzle body. The final control element includes a piezoelectric crystal array. The hydraulic coupler acts on the face end of the valve needle in such a way that it can be put into a first position that enables a pressure buildup, and a further position of the valve needle that enables the opening of a nozzle needle, with the pressure buildup and the valve opening being separately adjustable.
Claims10
In a unit injector (1) for injecting fuel into the combustion chamber of a self-igniting internal combustion engine, having a pump part (2), a nozzle part (3) and a final control element (5) that is followed downstream by a hydraulic coupler (38, 39) by way of which a valve needle (24) of a 2/2-way valve inside a nozzle body (23) is actuatable, the improvement wherein the final control element (5) comprises a piezoelectric crystal array (7) acting on the hydraulic coupler (38, 39) which acts upon one face end (40) of the valve needle (24) to put the valve needle (24) into a first position (41) that enables a pressure buildup, and a further position (43) of the valve needle (24) that enables the opening of a nozzle needle (29), whereby the pressure buildup and the valve opening are adjustable independently.
Dependencies are inferred from the claim text.