DAMPING ARRANGEMENT FOR DAMPENING ROTATIONAL IRREGULARITIES IN A DRIVE TRAIN OF A MOTOR VEHICLE

Abstract

A damping arrangement for dampening rotational irregularities in a drive train of a motor vehicle, having a slip arrangement providing slip between an input and output region of a torque-transmitting arrangement. The slip arrangement has a closed-loop control device that performs closed-loop control of the slip dependent on a measured signal for a rotational irregularity. The closed-loop control device performs closed-loop control of the slip dependent on at least one characteristic variable of a periodic oscillation component of an alternating component of a rotational speed proceeding from an average rotational speed. A sensor device is connected to the closed-loop control device and is designed to ascertain the average rotational speed in the torque-transmitting path downstream of the slip arrangement and to ascertain a frequency of the alternating component in the torque-transmitting path upstream of the slip arrangement.

Claims

1.-14. (canceled)

15. A damping arrangement configured to dampen rotational irregularities in a drive train of a motor vehicle, comprising: a slip arrangement configured to provide slip between an input region of a torque-transmitting arrangement and an output region of the torque-transmitting arrangement, comprising: a closed-loop control device configured to perform closed-loop control of the slip based at least in part on: a measured signal for a rotational irregularity, and at least one characteristic variable of a periodic oscillation component of an alternating component of a rotational speed proceeding from an average rotational speed; and at least one sensor device connected to the closed-loop control device and configured to: ascertain the average rotational speed in a torque-transmitting path downstream of the slip arrangement, and ascertain a frequency of the alternating component in the torque-transmitting path upstream of the slip arrangement.

16. The damping arrangement as claimed in claim 15, wherein the at least one sensor device is configured to ascertain an amplitude of the rotational irregularities as a characteristic variable in the torque-transmitting path downstream of the slip arrangement.

17. The damping arrangement as claimed in claim 15, wherein the at least one sensor device comprises a position sensor for a shaft of a drive of the motor vehicle.

18. The damping arrangement as claimed in claim 15, further comprising: a rotational irregularity pre-decoupling device, comprising at least one rotational-speed-adaptive absorber, arranged upstream of the slip arrangement, wherein the at least one sensor device comprises a primary rotational speed sensor arranged in the torque-transmitting path downstream of the rotational irregularity pre-decoupling device and upstream of the slip arrangement.

19. The damping arrangement as claimed in claim 16, wherein the at least one sensor device comprises, to ascertain the amplitude of the rotational irregularities as the characteristic variable, at least one of a secondary rotational speed sensor and a secondary acceleration sensor arranged in the torque-transmitting path downstream of the slip arrangement.

20. The damping arrangement as claimed in claim 16, wherein a transmission is arranged in the torque-transmitting path downstream of the slip arrangement, and the at least one sensor device is configured to ascertain the amplitude of the rotational irregularity in the torque-transmitting path downstream of the transmission.

21. The damping arrangement as claimed in any of claim 15, wherein the at least one sensor device is directly connected to the slip arrangement.

22. The damping arrangement as claimed in claim 15, wherein the closed-loop control device comprises a memory that comprises starting values for the closed-loop control of the slip arrangement.

23. The damping arrangement as claimed in claim 15, wherein the closed-loop control device comprises a memory that contains one or more values, which represent a predefined decoupling quality, and wherein the closed-loop control device is configured to perform closed-loop control of an amplitude of the slip until a predefined decoupling quality is attained.

24. The damping arrangement as claimed in claim 15, wherein the slip arrangement comprises a clutch configured to provide an average slip, and the closed-loop control device is configured to provide an average slip based at least in part on the at least one characteristic variable.

25. A method for dampening rotational irregularities in a drive train of a motor vehicle, comprising: providing slip between an input region of a torque-transmitting arrangement and an output region of the torque-transmitting arrangement by a slip arrangement; performing closed-loop control of the slip by a closed-loop control device based at least in part on: a measured signal for a rotational irregularity; and at least one characteristic variable of a periodic oscillation component of an alternating component of a rotational speed proceeding from an average rotational speed; and ascertaining by at least one sensor device connected to the slip arrangement the average rotational speed in a torque-transmitting path downstream of the slip arrangement and a frequency of the alternating component in the torque-transmitting path upstream of the slip arrangement.

26. The method as claimed in claim 25, further comprising: ascertaining oscillation nodes of the periodic oscillation component in the torque-transmitting path; and ascertaining the at least one characteristic variable by the at least one sensor device outside an ascertained oscillation nodes.

27. The method as claimed in claim 25, further comprising: increasing an average slip by the slip arrangement if a predefined maximum of an amplitude of the alternating component has been reached.

28. The method as claimed in claim 25, wherein a target decoupling quality is predefined for at least two different positions in the torque-transmitting path, and an amplitude of the alternating component is increased only to such an extent that the target decoupling quality is reached and is then kept constant.

29. The damping arrangement as claimed in claim 17, wherein the position sensor is a crankshaft position sensor.

30. The damping arrangement as claimed in claim 19, wherein a transmission is arranged in the torque-transmitting path downstream of the slip arrangement, and the at least one sensor device is configured to ascertain the amplitude of the rotational irregularity in the torque-transmitting path downstream of the transmission.

31. The damping arrangement as claimed in any of claim 21, wherein the at least one sensor device is directly connected to the closed-loop control device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Preferred designs and embodiments of the invention are illustrated in the drawings and will be discussed in more detail in the following description, wherein the same reference designations are used to denote identical or similar or functionally identical components or elements.

[0033] FIG. 1 is a damping arrangement; and

[0034] FIG. 2 is a method according to the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0035] FIG. 1 shows a damping arrangement according to an embodiment of the present invention.

[0036] FIG. 1 shows a damping arrangement 1 for a drive train of a motor vehicle. Here, the drive train comprises an engine 10 connected downstream in the torque flow, to a rotational irregularity pre-decoupling element 9. The rotational irregularity pre-decoupling element 9 is connected, further downstream in the torque flow, to a slip arrangement 2, wherein the slip arrangement 2 is connected at an output side to a transmission 11, and the transmission 11 is connected to further transmission elementsdenoted in FIG. 1 as the remaining drive train 12. A crankshaft position sensor 20 is arranged between the engine 10 and rotational irregularity pre-decoupling element 9. A rotational speed sensor 21 is arranged between the rotational irregularity pre-decoupling element 9 and the slip arrangement 2, and a further rotational speed sensor 22 is arranged between the slip arrangement 2 and transmission 11. The rotational speed sensor 21 is thus arranged in the input region 3 of the slip arrangement 2, and the rotational speed sensor 22 is arranged in the output region 4 of the slip arrangement 2.

[0037] The slip arrangement 2 comprises a closed-loop control device 6 and a sensor device 7. The sensor device 7 is connected to the three sensors 20, 21, and 22 and furthermore directly to the closed-loop control device 6 for the closed-loop control of the slip. This is advantageous owing to the real-time requirement of the signal processing: if the sensors 20, 21, and 22 have a direct data connection to the closed-loop control device 6, the delays that are possible in the case of a transmission via a bus system can be avoided.

[0038] The characteristic variables for the closed-loop control of the slip by the slip arrangement will now be described below. Below, these are the frequency, more specifically the modulation frequency, with which the slip is modulated, the average slip rotational speed, the amplitude of the modulation of the slip, and the phase angle thereof.

[0039] The modulation frequency, which is to be set by the slip arrangement 2, for the slip is in particular directly proportional to the engine rotational speed. In order to dampen the engine main order which is of particular relevance with regard to comfort, the modulation frequency is adapted exactly to the ignition frequency of the engine 10.

[0040] The rotational speed of the engine 10 is preferably ascertained upstream of the slip arrangement 2, because the rotational speed downstream of the slip arrangement 2 has already been reduced by the slip rotational speed. Since the slip rotational speed is variable, it is thus the case downstream of the slip arrangement 2 that there is no longer direct proportionality between the local rotational speed and the ignition frequency. The rotational speed of the engine 10, and/or the ignition frequency thereof, can be ascertained at various positions in the torque-transmitting path 8 upstream of the slip arrangement 2. It may for example be ascertained directly from the engine 10 by a crankshaft position sensor 20. What is particularly advantageous is an arrangement of a rotational speed sensor 21 in the torque-transmitting path 8 downstream of the rotational irregularity pre-decoupling element 9 and upstream of the slip arrangement 2. By the rotational irregularity pre-decoupling element 9, which may for example be composed of an arrangement of springs and rotational-speed-adaptive absorbers, the rotational speed at this location has already had a major part of the rotational irregularities eliminated therefrom. This has the advantages that parts of the rotational speed sensor 21 are subjected to lower mechanical loading, and that a more exact detection of the rotational speed directly at the functionally relevant location at the input region of the slip arrangement 2 is possible.

[0041] As a further characteristic variable, the average slip rotational speed is ascertained. For the ascertainment of the slip rotational speed, not only the rotational speed information for the primary side 3 of the slip arrangement 2 but also a rotational speed on the secondary side 4 of the slip arrangement 2 is required. The corresponding rotational speed sensor 22 may, as already stated, be arranged in the torque-transmitting path 8 downstream of the slip arrangement 2. The difference of the two rotational speed signals of the sensors 21 and 22 corresponds to the slip rotational speed, wherein consideration must also be given to the gear-ratio-dependent transmission ratio if the measurement point is not situated between the slip arrangement 2 and the transmission 11.

[0042] For the determination of the amplitude for the slip, the remaining rotational irregularity on the secondary side 4 of the slip arrangement 2 is determined as reference variable. This may be detected by an acceleration sensor, but particularly advantageously by the above-described rotational speed sensor 22, which is required in any case for the ascertainment of the slip rotational speed. The closed-loop control device 6 iteratively increases or reduces the amplitude in a manner dependent on the resulting change in the rotational irregularity ascertained by the sensor 22. The sensor 22 may in principle be arranged at any location in the drive train in the torque-transmitting path 8 downstream of the slip arrangement 2. Depending on the drive train, there are however positions at which so-called oscillation nodes occur. At these positions, at certain operating points, only small vibration amplitudes arise, whereas greater amplitudes arise at other positions of the drive train. The arrangement of the sensor 22 at such an oscillation node is unfavorable because, then, the reference variable for the closed-loop control is detected with an excessively small amplitudeor even with no amplitudeor it is even possible for the oscillation in the vicinity of an oscillation node to have an opposite phase in relation to the oscillation that is actually to be attenuated. The closed-loop control device 6 would then set ever greater amplitudes and become unstable.

[0043] In the case of a multi-stage automatic transmission for a rear-wheel-drive drive train of a motor vehicle with a rotational irregularity pre-decoupling device 9, comprising a spring accumulator and an oscillation absorber positioned downstream thereof, an oscillation node commonly occurs at the input of the transmission 11 at a particular rotational speed. In this respect, it is advantageous for the rotational speed sensor 22 arranged on the secondary side of the slip arrangement 2 to be arranged at the output of the transmission 11.

[0044] The phase angle of the modulation of the slip is preferably controlled in closed-loop fashion together with the amplitude by the closed-loop control device 6. The closed-loop control device 6 thus in particular iteratively adapts not only the amplitude but also the phase angle in accordance with the change in the at least one characteristic variable.

[0045] FIG. 2 shows steps of a method according to an embodiment of the present invention.

[0046] FIG. 2 schematically shows a slip arrangement 2 with a closed-loop control device 6 and corresponding steps for the closed-loop control of the slip, both of an average rotational speed of the slip and of a slip modulation. As input variables, the primary rotational speed upstream of the slip arrangement 2 is present in the form of a signal S21, and the secondary rotational speed downstream of the slip arrangement 2 is present in the form of the signal S22. The signals S21, S22 are utilized as reference variables both by a closed-loop control algorithm 15b for the Mode 2 slip referred to here and by a closed-loop control algorithm 15a for the Mode 1 slip referred to here.

[0047] The Mode 1 closed-loop control algorithm 15a provides, as controlled variable, an average pressure SW-MD or a variable derived therefrom, for example a corresponding position or actuation of a pressure control valve or the like, which leads to a particular transmissible torque and an average slip rotational speed of the slip arrangement 2. These may, as illustrated here, be received and implemented by a separate control unit 13a for an actuator 14a which activates the Mode 1 slip.

[0048] The Mode 2 closed-loop control algorithm 15b provides, as controlled variables SW-DM, the frequency, which is ascertained from the signal of the primary-side sensor 21, and also the amplitude and the phase angle of the modulation of a variable for an actuation of a slip device, in particular in the form of a clutch, which are ascertained from the signal S22 of the secondary-side sensor 22. These may, as illustrated here, be received and implemented by a separate control unit 13b for an actuator 14b which activates the Mode 2 slip.

[0049] In particular if the activation of the Mode 2 slip is performed by the same actuator 14a, 14b as the activation of the Mode 1 slip, the splitting into two different control units 13a, 13b can be omitted, such that all controlled variables are implemented by the same control unit 13a, 13b and one corresponding actuator 14a, 14b.

[0050] A data exchange 16 may take place between the closed-loop control algorithms 15a, 15b for the Mode 1 and the Mode 2 slip, for example in order to use the modulation amplitude for pilot control of the average slip rotational speed and prevent adhesion between the primary and secondary sides 3, 4 of the slip arrangement 2 even in the presence of large amplitudes. If the Mode 2 slip is already being operated with the maximum amplitude that can be provided by the associated actuator 13b, it is thus also possible to increase the average slip rotational speed by means of the actuator 14a in order to further improve the decoupling.

[0051] It may be advantageous to provide, for the closed-loop control device 6, starting values for phase and amplitude which shorten the response time when said closed-loop control device commences operation. By a parameter table, it is also possible for a target decoupling quality to be predefined for different operating points. The closed-loop control device 6 increases the amplitude of the modulation moment for the slip only until such time as the target decoupling quality has been attained, which leads to increased efficiency of the drive train.

[0052] In summary, the invention has inter alia the advantage that the decoupling and the efficiency of the drive train are improved. Furthermore, the damping of rotational irregularities in the drive train of motor vehicles is made possible in a reliable and efficient manner. A further advantage is that closed-loop control is performed in accordance with the actual decoupling requirement.

[0053] Although the present invention has been described on the basis of preferred exemplary embodiments, it is not restricted to these, but rather may be modified in a wide variety of ways.

[0054] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.