METHOD FOR IDENTIFYING LEAKS BY MEANS OF AN ACTUATOR

Abstract

A method for controlling an actuator includes providing the actuator with a control unit, a drive unit including an electric motor with a stator and a rotor, a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor, and a displacer unit, drivable by the rotation of the rotor, for displacing a fluid. The displacer unit includes a geometric displacement volume per revolution of the rotor. The method also includes generating a predetermined pressure at the displacer unit by applying an electrical driving power to the electric motor, maintaining the predetermined pressure over a predetermined time interval, determining the rotation of the rotor with the rotor position sensor during the predetermined time interval, and determining a leakage volume flow.

Claims

1.-7. (canceled)

8. A method for controlling an actuator, comprising: providing the actuator comprising: a control unit; a drive unit comprising an electric motor including a stator and a rotor; a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor; and a displacer unit, drivable by the rotation of the rotor, for displacing a fluid, the displacer unit comprising a geometric displacement volume per revolution of the rotor; generating a predetermined pressure at the displacer unit by applying an electrical driving power to the electric motor; maintaining the predetermined pressure over a predetermined time interval; determining the rotation of the rotor with the rotor position sensor during the predetermined time interval; and determining a leakage volume flow.

9. The method of claim 8, wherein the leakage volume flow is determined in accordance with the formula: QL=deltaINC*Vg/(INC/rotation)/t, wherein: QL is the leakage volume flow measured in liters/second; t is the predetermined time interval measured in seconds; deltaINC is equivalent to (INCENDINCSTART) and is a number of increments performed by the rotor in the predetermined time interval; Vg is the geometric displacement volume per revolution of the rotor measured in liters/revolution; and t is the predetermined time interval in seconds.

10. The method of claim 8, wherein the method is carried out at different predetermined pressures.

11. The method of claim 8, wherein the leakage volume flow is considered in volume flow control of the displacer unit by the actuator.

12. The method of claim 8, wherein a characteristic map for the leakage volume flow for different pressures is determined by determining the leakage volume flow at the predetermined pressure.

13. The method of claim 8, wherein the method is carried out continuously or periodically.

14. A motor vehicle for carrying out the method of claim 8, comprising: the actuator; and a motor vehicle component, actuatable by the actuator.

15. The motor vehicle of claim 14 wherein the motor vehicle component is a clutch or a transmission assembly.

16. The method of claim 8, wherein the leakage volume flow is determined in accordance with the formula: QL=deltaINC*Vg/(INC/rotation)/t, wherein: QL is the leakage volume flow; t is the predetermined time interval; deltaINC is a number of increments performed by the rotor in the predetermined time interval; Vg is the geometric displacement volume per revolution of the rotor; and t is the predetermined time interval.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure and the technical environment are explained in greater detail below by means of the figures. It should be noted that there is no intention to restrict the invention by the illustrative embodiments shown. Unless explicitly stated otherwise, it is also possible to isolate partial aspects of the situations explained in the figures and to combine them with other components and insights from the present description and/or figures. It should be noted that the figures and especially the size relationships illustrated are only schematic. Identical reference signs denote identical objects, and therefore supplementary explanations from different figures can be drawn upon if appropriate. In the drawings:

[0028] FIG. 1 shows an actuator with a plurality of motor vehicle components;

[0029] FIG. 2 shows part of an actuator in a perspective view; and

[0030] FIG. 3 shows another part of an actuator in an exploded perspective view.

DETAILED DESCRIPTION

[0031] FIG. 1 shows an actuator 1 with a plurality of motor vehicle components 10, 11, 12. The actuator 1 has a drive unit 2 with an electric motor 3, which comprises a rotor 6 (ref. FIG. 3), and a control unit 4. The actuator 1 has a displacer unit 9 (e.g. a fluid pump), drivable by the rotation 7 of the rotor 6, for displacing a fluid, wherein the displacer unit 9 has a certain geometric displacement volume per revolution of the rotor 6. The hydraulic circuit 14 of the actuator comprises a reservoir 13 for the fluid and a valve assembly 15 for actuating the motor vehicle components 10, 11, 12. Here, the first motor vehicle component 10 and the second motor vehicle component 11 are each illustrated as clutches. Here, the third motor vehicle component 12 is a transmission assembly. The valve assembly 15 is a two pressure valve, which ensures in a simple manner that a pressure can only be applied in one delivery direction of the displacer unit 9 and that a switch can be made to the other delivery direction after the dissipation of this pressure.

[0032] In step a) of the method, a predetermined pressure is set at the displacer unit 9. This can be determined, for example, in the hydraulic circuit 14, e.g. by means of the pressure sensor 16 (ref. FIG. 2). The pressure is set and regulated by means of an electrical driving power of the motor 3.

[0033] In step b) of the method, the predetermined pressure is maintained for a predetermined time interval.

[0034] In step c), rotation 7 of the rotor 6 is monitored and evaluated by the rotor position sensor 8 in the time interval, i.e. the increments performed within the time interval are determined. If, therefore, rotation 7 of the rotor 6 is required to maintain the pressure, leakage at the displacer unit 9 and/or in the hydraulic circuit 14 can be assumed. A leakage volume flow can be determined via the rotation 7 of the rotor 6.

[0035] The leakage volume flow thus determined can be taken into account for improved control of the actuator 1 by the control unit 4 in the actuation of the actuator 1. Thus, for example, volume flow control, in which the actuator 1 is controlled by controlling the delivery volume of the displacer unit 9, can be performed more accurately. Furthermore, a state of the actuator 1 can be monitored via a change in the leakage volume flow. A change in the leakage volume flow (at the predetermined pressure) can indicate wear of the actuator 1 or of components in the hydraulic circuit 14 (e.g. valve assembly 15, motor vehicle components 10, 11, 12 etc.).

[0036] FIG. 2 shows part of an actuator 1 in perspective view. The actuator 1 has a drive unit 2 with an electric motor 3 (ref. FIG. 3) and a control unit 4. The motor 3 has at least one stator 5 and one rotor 6 (see FIG. 3), and rotation 7 of the rotor 6 can be detected by means of a rotor position sensor 8, which is connected to the control unit 4. A pressure applied to the displacer unit 9 (and/or a pressure in the hydraulic circuit) can be ascertained by means of a pressure sensor 16.

[0037] FIG. 3 shows another part of an actuator 1 in an exploded perspective view. The actuator 1 has a drive unit 2 with an electric motor 3 and a control unit 4. The motor 3 has at least one stator 5 and one rotor 6, and rotation 7 of the rotor 6 can be detected by means of a rotor position sensor 8, which is connected to the control unit 4.

REFERENCE NUMERALS

[0038] 1 actuator [0039] 2 drive unit [0040] 3 motor [0041] 4 control unit [0042] 5 stator [0043] 6 rotor [0044] 7 rotation [0045] 8 rotor position sensor [0046] 9 displacer unit [0047] 10 first motor vehicle component [0048] 11 second motor vehicle component [0049] 12 third motor vehicle component [0050] 13 reservoir [0051] 14 hydraulic circuit [0052] 15 valve assembly [0053] 16 pressure sensor [0054] 17 motor vehicle