Method and open-loop and closed-loop control device for compensating for a clutch torque of a hybrid separating clutch taking into consideration the rotational speed of an electric machine

Abstract

A method and an open-loop and closed-loop control device for compensating for a clutch torque of a separating clutch located between an internal combustion engine and an electric machine in a hybrid drive of a motor vehicle. The compensation takes into consideration the rotational speed of the electric machine. The rotational speed of the electric machine impacts clutch torque. A compensation factor is calculated, and increases or decreases the necessary clutch torque, causing a corresponding actuation of an actuator to achieve the necessary clutch torque.

Claims

1. A method for compensating for a clutch torque of a separating clutch of a hybrid drive of a motor vehicle, taking into consideration a rotational speed of an electric machine, wherein the separating clutch is provided between an internal combustion engine and the electric machine and an actuator is assigned to the separating clutch for the actuation of the same comprising: a calibration function, which represents a factor as a function of the rotational speed of the electric machine is stored in a memory of an open-loop and closed-loop control device; during driving operation an appropriate clutch torque is required from the separating clutch and, by using the calibration function, a disengagement travel is calculated and set on the actuator; and depending on the rotational speed of the electric machine, a factor is calculated which internally increases or decreases the required clutch torque.

2. The method as claimed in claim 1, wherein the factor that depends on the rotational speed of the electric machine is the disengagement travel of the actuator, which is added to or subtracted from a current position of the actuator, in order to counteract an influence of the rotational speed of the electric machine on the required clutch torque.

3. The method as claimed in claim 1, wherein the factor that depends on the rotational speed of the electric machine is calculated chronologically between the clutch torque required during driving operation and the calculation of a position of the actuator.

4. The method as claimed in claim 1, wherein a position of the actuator is set which depends on a characteristic curve of the clutch torque and at the same time on the rotational speed of the electric machine.

5. A system for compensating for a clutch torque of a separating clutch which is provided between an internal combustion engine and an electric machine, the system comprising: an open-loop and closed-loop control device including a memory, in which a calibration function which represents a factor as a function of a rotational speed of the electric machine is stored; and an actuator of the separating clutch connected to the open-loop and closed-loop control device via a communications link, wherein, via the communications link during driving operation the actuator receives from the open-loop and closed-loop control device a measure for a disengagement travel of the actuator, in order to set a required clutch torque of the separating clutch; wherein the electric machine is connected via the communications link to the open-loop and closed-loop control device, which, depending on the rotational speed of the electric machine, calculates a factor which internally increases or reduces the required clutch torque of the separating clutch.

6. The open-loop and closed-loop control device as claimed in claim 5, wherein by using the actuator of the separating clutch, the disengagement travel of the separating clutch that is calculated as a function of the rotational speed of the electric machine can be set.

7. A system for compensating a clutch torque of a separating clutch, the system comprising: the separating clutch located axially between an internal combustion engine and an electric machine: an actuator configured to selectively actuate the separating clutch; and a control device coupled to the electric machine and configured to: determine a rotational speed of the electric machine, and determine a required clutch torque for actuation of the separating clutch that increases or decreases depending on the rotational speed of the electric machine, commanding the actuator to move a desired travel distance that corresponds with the rotational speed of the electric machine to achieve the required clutch torque wherein the clutch includes a disk spring, a pressure plate, and a mating pressure plate, wherein the disk spring, the pressure plate, and the mating pressure plate are integrated with a rotor of the electric machine to rotate therewith.

8. The system of claim 7, wherein the clutch further includes a clutch disk configured to co-rotationally connect to the internal combustion engine, wherein the disk spring co-rotationally connected to the electric machine, wherein the pressure plate co-rotationally connected to the electric machine, and wherein the mating pressure plate co-rotationally connected to the electric machine.

9. The system of claim 7, wherein the control device is an open-loop and closed-loop control device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments will explain the invention and its advantages in more detail below by using the appended figures. The size relationships in the figures do not always correspond to the actual size relationships, since some shapes are represented as simplified and other shapes as enlarged in relation to other elements, for purposes of improved illustration. In the figures:

(2) FIG. 1 shows a schematic view of a separating clutch which is arranged between an internal combustion engine and an electric machine (serial hybrid drive train);

(3) FIG. 2 shows a schematic illustration of a hybrid drive for a motor vehicle, in which a method for compensating for a clutch torque of a hybrid separating clutch, taking into consideration the rotational speed of an electric machine, is implemented, and

(4) FIG. 3 shows a schematic representation of the mode of action of the actuator on the separating clutch.

(5) Identical designations are used for identical or identically acting elements of the disclosure. In addition, for clarity, only designations which are required for the description of the respective figure are illustrated in the individual figures.

DETAILED DESCRIPTION

(6) FIG. 1 shows a schematic illustration of a separating clutch 4, which is provided between an internal combustion engine 2 and an electric machine 6 of an embodiment of a hybrid drive 1. The separating clutch 4 comprises a clutch disk 16, a disk spring 17, a pressure plate 18 and a mating pressure plate 19. The clutch disk 16 is co-rotationally connected to the internal combustion engine 2. The disk spring 17, the pressure plate 18 and the mating pressure plate 19 are co-rotationally connected to the electric machine 6. In one embodiment, the disk spring 17, the pressure plate 18 and the mating pressure plate 19 are integrated with the rotor (not illustrated) of the electric machine 6 and rotate at the speed of rotation thereof (rotational speed).

(7) FIG. 2 shows a schematic view of an embodiment of an open-loop and closed-loop control device 12 for compensating for a clutch torque of a separating clutch 4 which is provided between the internal combustion engine 2 and the electric machine 6 of a hybrid drive 1. The open-loop and closed-loop control device 12 comprises a memory 11, in which the calibration function (not illustrated) is stored. The calibration function represents a factor as a function of the rotational speed of the electric machine 6. The hybrid drive 1 substantially comprises the internal combustion engine 2, the separating clutch 4, the electric machine 6 and a transmission 10. All these elements are each connected to the open-loop and closed-loop control device 12 via a communications link 20. In addition, the electric machine 6 in the embodiment illustrated is assigned a charging device 14, via which an energy store 15 connected to the charging device 14 can be charged and via which the electric machine 6 takes the energy required for the drive from the energy store 15. The charging device 14 is likewise connected to the open-loop and closed-loop control device 12 via a communications link 20. Via the communications link 20, during driving operation, for example, the rotational speed of the internal combustion engine 2 and the rotational speed of the electric machine 6 are supplied to the open-loop and closed-loop control device 12. As already mentioned above, an appropriate calibration function, which represents a factor as a function of the rotational speed of the electric machine 6, is stored in the memory 11. During driving operation, the separating clutch 4 requires an appropriate clutch torque. By using the calibration function stored in the memory 11, a disengagement travel 9 of the actuator 8 (see FIG. 3) can be set in order that the disengagement travel 9 is matched to the rotational speed of the electric machine 6. Thus, by using the calibration function, a factor is calculated which, taking into consideration the rotational speed of the electric machine 6, internally increases or reduces the required clutch torque of the separating clutch 4. This has the advantage that the action of the rotational speed of the electric machine 6 compensates for the torque capacity of the separating clutch 4.

(8) FIG. 3 shows a schematic representation of the separating clutch 4 in conjunction with the actuator 8. The actuator 8 is provided on the side of the disk spring 17, pressure plate 18 and mating pressure plate 19. This means that the actuator 8 is provided on that side of the elements (disk spring 17, pressure plate 18 and mating pressure plate 19) of the separating clutch 4 which rotate at the rotational speed of the electric machine 6. The arrow P1 indicates the direction of the electric machine 6. The arrow P2 indicates the direction of the internal combustion engine 2. As already mentioned in the description relating to FIG. 2, by using the rotational speed of the electric machine 6, a factor is calculated which internally increases or reduces the required clutch torque. Depending on the driving situation or driving mode, an appropriate clutch torque is required from the separating clutch 4 in order to match the clutch torque to the rotational speed of the electric machine 6. Consequently, a corresponding disengagement travel 9, which is added to or subtracted from the current position of the actuator 8, is set on the actuator 8. This has the advantage that, as a result, the influence of the rotational speed of the electric machine 6 on the torque capacity can be counteracted and the accuracy of the torque capacity can be adjusted as a function of the disengagement travel 9. The magnitude of the disengagement travel 9 of the separating clutch 4 is thus likewise a measure of the torque capacity. The position of the actuator 8 is thus set depending on the calibration function (torque characteristic curve) and at the same time on the rotational speed of the electric machine 6. Thus, the action of the rotational speed effect on the torque capacity of the separating clutch 4 is compensated.

(9) The disclosure has been described in relation to embodiments, which are in no way to be understood as a restriction of the claims. However, changes and modifications can be made without departing from the protective scope of the following claims.

LIST OF DESIGNATIONS

(10) 1 Hybrid drive 2 Internal combustion engine 4 Separating clutch 6 Electric machine 8 Actuator 9 Disengagement travel 10 Transmission 11 Memory 12 Open-loop and closed-loop control device 14 Charging device 15 Energy store 16 Clutch disk 17 Disk spring 18 Pressure plate 19 Mating pressure plate 20 Communications link A Direction of the axis P1 Arrow (direction of the electric machine) P2 Arrow (direction of the internal combustion engine) R Radial direction