Method for adapting a biting point filling time of a hydraulically actuated hybrid disengaging clutch

Abstract

A method for adapting a biting point filling time of a hydraulically actuated hybrid disengaging clutch is implemented step by step during driving of the motor vehicle via a plurality of selected engagement phases of the hybrid disengaging clutch with a manipulation of the customary rapid filling routine. Proceeding from an initially stored biting point filling time, a filling time which is shortened in comparison with this for a subsequent rapid filling routine is increased step by step, in each case by an increment. Here, an actual value which is set in each case for a test parameter, from which a change in the transmission of torque of the hybrid disengaging clutch can be derived, is detected until the actual value corresponds to a setpoint value.

Claims

1. A method for adapting a biting point filling time of a hydraulically actuated hybrid disengaging clutch arranged in a hybrid drive train of a motor vehicle between an internal combustion engine and an electric machine, the method comprising: a) detecting engagement operations of the hybrid disengaging clutch during a driving operation of the motor vehicle, in each of the engagement operations a hydraulic system actuating the hybrid disengaging clutch is filled with fluid in a rapid filling routine, and selecting one of the engagement operations; b) implementing the rapid filling routine of the selected one of the engagement operations, the hydraulic system filled during the rapid filling routine of the selected one of the engagement operations with a predetermined filling pressure over a filling time that corresponds to either, in a first adaptation, a filling time shortened relative to a stored initial biting point filling time, or, in a later adaptation after the initial adaption, a filling time shortened relative to a most recently determined biting point filling time; c) increasing a shortened filling time by a predetermined increment to an extended filling time, and sampling an actual value for a test parameter, a transmission of torque via the hybrid disengaging clutch derivable directly or indirectly by the test parameter; and d) comparing the actual value for the test parameter with a setpoint value stored for the test parameter, wherein either the extended filling time is used as an adapted biting point filling time for subsequent, non-selected engagement operations when the actual value is greater than or equal to the set-point value, or the extended filling time is used as the shortened filling time for a repeated implementation of the step b), and steps a) through d) are repeated when the actual value is less than the setpoint value.

2. The method of claim 1, further comprising storing the extended filling time as the adapted biting point filling time when the actual value is greater than or equal to the setpoint value.

3. The method of claim 1, further comprising: calculating and storing a difference between the extended filling time and the initial biting point filling time as a filling time offset when the actual value is greater than or equal to the setpoint value; and determining the adapted biting point filling time from the initial biting point filling time and the stored filling time offset.

4. The method of claim 1, wherein an increment is specified to be increasingly smaller for sequential selected engagement operations.

5. The method of claim 1, further comprising: sampling actual values for at least one further test parameter that the transmission of torque via the hybrid disengaging clutch is derivable directly or indirectly; and comparing each of the at least one further test parameter with a respective additional setpoint value stored for at least one test parameter.

6. The method of claim 5, wherein the test parameter or the at least one further test parameter comprises a gradient change in a rotational speed of the electric machine connected to the hybrid disengaging clutch.

7. The method of claim 5, wherein the test parameter or the at least one further test parameter comprises a change in a torque for rotational speed regulation of the electric machine connected to the hybrid disengaging clutch.

8. The method of claim 5, wherein the test parameter or the at least one further test parameter comprises a change in a balanced torque on the electric machine connected to the hybrid disengaging clutch.

9. The method of claim 1, wherein the test parameter is a gradient change in a rotational speed of the electric machine connected to the hybrid disengaging clutch.

10. The method of claim 1, wherein the test parameter is a change in a torque for rotational speed regulation of the electric machine connected to the hybrid disengaging clutch.

11. The method of claim 1, wherein the test parameter is a change in a balanced torque on the electric machine connected to the hybrid disengaging clutch.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following text, example aspects of the invention will be explained in greater detail using one exemplary embodiment on the basis of the drawing, in which:

(2) FIG. 1 shows a flow chart.

DETAILED DESCRIPTION

(3) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(4) The method according to example aspects as a rule takes place in a plurality of repeating method steps, for which in each case the rapid filling routine of engagement operations which take place regularly and successively during driving of a motor vehicle is utilized. Here, the customary rapid filling routine is in each case manipulated, and a filling offset is determined iteratively with respect to an initial biting point filling time in the case of a first adaptation or with respect to a previously adapted biting point filling time in the case of a repeated implementation of the method (repeated adaptation). A filling offset is in each case the difference, which changes over the service life of the vehicle, between the initial biting point filling time and an adapted biting point filling time which has to be set, in order to set the disengaging clutch as precisely as possible to the biting point. The changing biting point filling time is determined by the method and is set as an adapted biting point filling time in the case of subsequent engagement operations on the disengaging clutch.

(5) By way of the engagement operation of a hybrid disengaging clutch, an active attachment operation of an internal combustion engine to an electric machine of a hybrid drive train of a motor vehicle takes place. The engagement operation includes a rapid filling routine, as a rule with a rapid filling phase and a filling phase, and a subsequent clutch phase. In a rapid filling routine which takes place regularly, the disengaging clutch is filled over a predefined filling time with a fluid at a predetermined filling pressure in the rapid filling phase and in the filling phase, a setting pressure which is determined by the filling time being set at the disengaging clutch. Here, the filling time corresponds to the initial biting point filling time or a biting point filling time which has already previously been adapted.

(6) In contrast to this, in the case of a rapid filling routine which is manipulated according to example aspects of the invention, the hybrid disengaging clutch is filled by way of a filling time which is shortened with respect to an initial biting point filling time or a previously adapted biting point filling time and is approximated iteratively in directly or indirectly subsequent rapid filling routines of selected engagement operations to the initial or possibly the already previously adapted biting point filling time, as has to be set at this time in order to set the biting point of the clutch.

(7) In the following text, the procedure of the method (shown in FIG. 1 as a flow chart) will be explained.

(8) In a manner which has preferably been pre-programmed at the factory, the method begins by, for example, the engagement operations being detected, from a defined odometer value of the motor vehicle, and being checked automatically for suitability for use for the implementation of the method. After the determination of the suitability of an engagement operation, the latter is selected for the implementation of the method, and the rapid filling routine is carried out on a hydraulic system which actuates the hybrid disengaging clutch.

(9) During the rapid filling phase, over a predefined filling time, the locking chamber of the hydraulic system is first of all filled proportionately with a fluid under a rapid filling pressure (rapid filling pulse), before the rapid filling pressure is lowered to a lower known filling pressure and the hydraulic system is filled further over a remaining rest of the predetermined filling time. Here, the filling time is shorter than the initial biting point filling time or possibly already determined adapted biting point filling time, after which a setting pressure which correlates with the biting point has been set on the disengaging clutch.

(10) The hybrid disengaging clutch is then applied further by a step, that is to say the shortened filling time is increased by an increment to an increased filling time. After only a short waiting time, in which a setting pressure which correlates with the increased filling time has been set at the clutch, an actual value which is set for a selected test parameter is detected, from which a change in the transmission of torque by way of the hybrid disengaging clutch can be derived directly or indirectly. This can be, for example, a gradient change of the rotational speed of the electric machine, a change in the torque for rotational speed regulation of the electric machine, or a change in the balanced torque at the electric machine. The actual value which is set of the test parameter is compared with a setpoint value which is stored for the test parameter. The setpoint value correlates with beginning transmission of torque, which is not yet significant, by way of the disengaging clutch when the disengaging clutch is situated in the biting point position.

(11) In the case of the actual value being identical to the setpoint value, it can be concluded that the increased setting pressure which correlates with the increased filling time corresponds to the biting point pressure. Should the determined actual value have already exceeded the setpoint value, it can be concluded that the actual biting point filling time lies within the change range of the filling time. In order to determine the actual biting point as precisely as possible, the magnitude of the change in the filling time (increment) is selected to be very small, with the result that, in further method steps, the filling time approaches the actual biting point filling time iteratively from below over a large number of small steps. In the case of the setpoint value being reached by way of an actual value, the assumption is then made that the increased filling time has reached the actual biting point filling time. The smaller a magnitude of the increment, by which the filling time is increased in each case, the more precisely the actual biting point filling time can ultimately be determined and utilized as an adapted biting point filling time for further regular engagement operations.

(12) If, after a first increase in the filling time, a beginning transmission of torque cannot yet be derived from the actual value of the parameter, which corresponds to the norm, the extended filling time is stored for a continuation of the method in a later method step which takes place during a later clutch operation, whereby the current clutch operation is not delayed any longer. In addition, in a manner which is assigned to this, the detected actual value of the detected parameter is stored. The current engagement operation is now concluded.

(13) A next suitable engagement operation is selected, in the case of which the directly previously set extended filling time forms the starting point. This is increased by an increment in an analogous manner with respect to the previous engagement operation utilized for the method. Here, the magnitude of the increment, by which in each case the filling time is increased per engagement operation, can be identical, or it becomes increasingly smaller, whereby the actual biting point filling time can be determined very precisely with a comparatively small number of iteration steps. Subsequently, the actual value of the parameter is detected again, from which a change in the transmission of torque by way of the disengaging clutch can be derived directly or indirectly and can be compared with the stored setpoint value for the parameter.

(14) Further adaptation attempts follow in each case in a subsequent clutch phase until the respective actual value for the detected parameter corresponds to the setpoint value. The extended filling time which is then set is adopted as the actual biting point filling time at the detection time and is stored (adapted biting point filling time). The adapted biting point filling time is then set for all subsequent clutch phases.

(15) It goes without saying that the change of two relevant parameters can also be tracked and analyzed during the method. In this way, the value comparison of one parameter can be verified.

(16) The method can be repeated again and again over the service life of the vehicle, the most recently adapted biting point filling time then in each case forming the starting point. It is advantageous here, instead of the respective determined biting point filling time, to store in each case the filling offset, and to then determine the last adapted biting point filling time in each case from the initial biting point filling time and the most recently stored biting point offset.

(17) Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.