METHOD FOR OPERATING A FLUID-GUIDING DEVICE, AND CORRESPONDING FLUID-GUIDING DEVICE

Abstract

A device and method for operating a fluid-guiding device, including an electrically operated fluid pump, which delivers fluid from a fluid sump of the fluid-guiding device and supplies it to at least one fluid consumer. A fluid volume in the fluid sump as well as a current intensity of the electric current taken up by the fluid pump and modeled on the basis of the rotational speed of the fluid pump are ascertained, and a comparison value is determined from the modeled current intensity. A deficient fluid supply of the fluid-guiding device is inferred if the fluid volume is greater than a threshold value and a measured current intensity of the electric current taken up by the fluid pump is less than the comparison value.

Claims

1-10. (canceled)

11. A method for operating a fluid-guiding device, comprising: an electrically operated fluid pump, which delivers fluid from a fluid sump of the fluid-guiding device and supplies it to at least one fluid consumer, wherein a fluid volume in the fluid sump and a current intensity of the electric current taken up by the fluid pump is modeled based on a rotational speed of the fluid pump, and a comparison value is determined from the modeled current intensity, wherein a deficient fluid supply of the fluid-guiding device is inferred if the fluid volume is greater than a threshold value and a measured current intensity of the electric current taken up by the fluid pump is less than the comparison value.

12. The method according to claim 11, wherein the fluid volume is ascertained by a model.

13. The method according to claim 11, wherein the fluid volume per unit of time is reduced by a removal volume determined based on the rotational speed of the fluid pump, and in that the fluid volume per unit of time is increased by a feed volume determined based on of the temperature.

14. The method according to claim 11, wherein the modeled fluid volume is bounded at the bottom by a minimum value and at the top by a maximum value.

15. The method according to claim 11, wherein during a startup operation of the fluid-guiding device, the fluid volume is set at an initial value determined based on a standing time of the fluid-guiding device.

16. The method according to claim 11, wherein the modeled current intensity is ascertained based on the rotational speed of the fluid pump and the temperature by means of a mathematical relation, a characteristic field, and a table.

17. The method according to claim 16, wherein the mathematical relation, the characteristic field, and the table are adapted at least once, preferably periodically, with the measured current intensity.

18. The method according to claim 11, wherein the comparison value is ascertained from the modeled current intensity by using a variable offset and a constant offset.

19. The method according to claim 18, wherein the variable offset is ascertained as a function of the rotational speed of the fluid pump.

Description

The invention shall be explained in more detail below based on the exemplary embodiments represented in the drawing, without this limiting the invention. The single FIGURE shows:

[0030] FIGURE: a flow chart of a method for operating a fluid-guiding device.

[0031] The FIGURE shows a flow chart of a method for operating a fluid-guiding device. The device provides an electrically operated fluid pump, which delivers fluid from a fluid sump of the fluid-guiding device and supplies it to at least one fluid consumer, for example a fluid outlet.

[0032] First of all, by means of a model, a fluid volume in the fluid sump is ascertained. For this, in a step 1, an initial value is determined for the fluid volume and the fluid volume is set at this initial value. The initial value, for example, is ascertained based on standing time of the fluid-guiding device. Preferably, the initial value increases as the standing time of the fluid-guiding device increases. The standing time is ascertained, for example, by means of a timekeeper, especially a controller of the fluid-guiding device. Next, in a step 2, the fluid volume is reduced by a removal volume. In a step 3, on the other hand, the resulting fluid volume is increased by a feed volume.

[0033] While the removal volume, for example, depends directly on the rotational speed of the fluid pump, preferably the feed volume is determined based on a temperature. The temperature corresponds, for example, to a temperature of the fluid-guiding device, especially a fluid temperature of the fluid. Then, in a step 4, the modeled fluid volume is bounded at the bottom by a minimum value and at the top by a maximum value, so that the modeled fluid volume lies in an interval enclosed between the minimum value and the maximum value. This procedure is repeated, starting from step 2. Preferably, steps 2, 3 and 4 occur during a given unit of time and are permanently repeated until an end of operation of the fluid-guiding device is reached. The unit of time corresponds, for example, to at least 10 ms and/or at most 20 ms, at most 40 ms or at most 80 ms.

[0034] In parallel with this, in a step 5 a modeled current intensity is determined based on the rotational speed of the fluid pump. In addition, the already mentioned temperature can be used. The modeled current intensity is preferably determined from a mathematical relation, a characteristic field, and/or a table. The mathematical relation, characteristic field, and/or table can be adapted in the course of a permanently recurring step 6 by means of a measured current intensity.

[0035] For this purpose, in addition to the measured current intensity one furthermore determines the rotational speed of the fluid pump as well as the temperature, and uses these variables to adapt the relation, the characteristic field, and/or the table. Step 5 is followed immediately by step 7. In this step, the modeled current intensity is adapted by a variable offset, for example, it is reduced by the variable offset. The variable offset is preferably determined as a function of the rotational speed of the fluid pump.

[0036] The thus resulting modeled current intensity is then adapted in a step 8 with a constant offset. This is or will be established once and then remains constant. On the whole, the modeled current intensity obtained by using the variable offset and/or the constant offset yields a comparison value. This comparison value is compared in the following step 9 with the measured current intensity. At the same time, the fluid volume is compared with a threshold value. In particular, it is examined whether the fluid volume is greater than the threshold value and whether the measured current intensity is smaller than the comparison value. If these two conditions are met, a deficient fluid supply of the fluid-guiding device is recognized in the course of step 10. If such is the case, suitable countermeasures can be instituted.

[0037] With the help of the above-explained method, the presence of an adequate quantity of fluid can be inferred without a sensor to ascertain the available fluid quantity in the fluid-guiding device. In particular, a deficient fluid supply of the fluid-guiding device is recognized if the fluid quantity should not be sufficient.