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AssigneeRobert Bosch GmbH
InventorJohannes-Joerg Rueger
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According to the present invention, a method is proposed for determining the rail pressure of an injector having a voltage-controlled piezoelectrical actuator, the piezoelectrical actuator (2) actuating a nozzle needle (11) using hydraulic coupler (4). As a result of the pressure in the high-pressure channel (13), a coupler pressure (Pk) is built up via the hydraulic coupler (4), the coupler pressure inducing a piezovoltage (Ui) in the actuator (2). Because this voltage value is redundant with regard to the pressure value in the high-pressure channel (13), which is measured by a pressure sensor (D), the voltage value can be used for monitoring the functioning of the pressure sensor (D). In the event of the failure of the pressure sensor (D), emergency operation can be built up for the injector (1) with the assistance of the induced voltage (Ui). The injector (1) advantageously functions for injecting fuel in an internal combustion engine.
A method for determining the rail pressure (P1) of an injector (1), having a voltage-controlled piezoelectrical actuator (2), the piezoelectrical actuator (2) actuating a nozzle needle (11) using a hydraulic coupler (4), in order to release a quantity of fluid that is acted upon by the rail pressure (P1) in a high-pressure channel (13), wherein the rail pressure (P1) acts upon the piezoelectrical actuator (2) via the hydraulic coupler (4) and generates a piezovoltage (Ui) in the actuator (2), and the rail pressure (P1) is calculated from the piezovoltage (Ui) using a preestablished algorithm.
The method as recited in one of the preceding claims, wherein the piezovoltage (Ui) is measured, in temporal terms, immediately before the subsequent charging operation of the coupler (4).
The method as recited in one of the preceding claims, wherein a pressure sensor (D) is provided, which is positioned at an appropriate location in the high-pressure system, and the measured rail pressure is compared to the calculated rail pressure.
The method as recited in one of the preceding claims, wherein the injector is used for injecting fuel into a common rail system of an internal combustion engine.
Dependencies are inferred from the claim text.