Patent Application
20230228326
This application claims the benefit of and right of priority under 35 U.S.C. § 119 to German Patent Application no. 10 2022 200 531.7, filed on 18 Jan. 2022, the contents of which are incorporated herein by reference in its entirety
The invention relates to a control method for calibrating an actuation of a converter lock-up clutch of a hydrodynamic torque converter. The invention also relates to a control unit for carrying out a control method of that type, a transmission device with such a control unit, and a vehicle with the said transmission.
DE 10 2014 222 948 A1 describes a control method for calibrating an actuation of a converter lock-up clutch of a hydrodynamic torque converter, in which, by means of a single shifting element in the transmission, the turbine wheel of the hydrodynamic torque converter connected thereto is braked.
DE 44 44 843 A1 describes a power-split, multi-gear transmission with shifting elements in the form of shifting clutches.
In one aspect, the invention relates to a control method for calibrating an actuation of a converter lock-up clutch of a hydrodynamic torque converter, having a pump wheel and a turbine wheel which is connected to a power-split transmission, wherein the transmission comprises at least two clutches respectively associated with a power-split shaft assembly, which clutches can be actuated separately to open and close in order to apply a clutch torque to the turbine wheel, so that a rotation speed difference between the pump wheel and the turbine wheel changes, the said method comprising the following steps:
The closing can include active or passive closing. In active closing the frictional performance of the clutch concerned is increased. In passive closing the frictional performance of the clutch concerned is kept constant, in that the clutch is kept closed. Correspondingly, at least two clutches respectively each associated with a different power-split shaft assembly of the transmission can be actuated to close simultaneously. Opening refers to an active opening in which the frictional performance of the clutch concerned is reduced.
The actual rotation speed difference can be a measured rotation speed difference. In that case a measurement of an actual rotation speed difference can be carried out. This measurement can take place by determining a difference between the actual rotation speed of the pump wheel and the actual rotation speed of the turbine wheel.
The transmission can comprise two, three, four, five or even more clutches each associated with a power-split shaft assembly. Also, with a power-split shaft assembly there can be associated one, two, three or even more of the clutches. If each of the at least two clutches associated with a respective power-split shaft assembly is opened, then no clutch torque can be applied to the turbine wheel. The at least two clutches of the transmission, each associated with a power-split shaft assembly, can be clutches on the input side of the transmission. The specified rotation speed can correspond to a rotation speed of a drive unit connected to the pump wheel. The simultaneous closing can be quantitatively the same as or different from the clutch torque that results therefrom.
In a further embodiment, it can be provided that before a clutch torque is applied to the turbine wheel, the set-point rotation speed difference is divided into at least two ranges, and in two of the said at least two ranges a different number of clutches is actuated to close them in order to reach the specified set-point rotation speed difference.
In a further embodiment it can be provided that a) the set-point rotation speed difference, b) the number of ranges into which the set-point rotation speed difference is divided, or c) the number of clutches actuated in each range, is specified. Two of the parameters a), b), and c) can be predetermined. Alternatively, all three parameters a), b), and c) can be predetermined. The ranges can be the same size or of different sizes. Thus, for example, from the first of the set-point rotation speed differences at the farthest range, the ranges can, for example, become larger toward the range next to the last of the set-point rotation speed differences. The size of a range can be adapted to the maximum clutch torque of the respective clutches actuated therein. The maximum clutch torque is the maximum acceptable frictional performance for a clutch. Thus, the said adaptation can take place on the basis of the lowest maximum clutch torque of the respective clutches actuated therein. The lowest range can begin at a rotation speed difference of 0. The highest range ends at the set-point rotation speed difference.
In a further embodiment it can be provided that the number of ranges into which the set-point rotation speed difference is divided is smaller or equal to the number of clutches that can be actuated separately in order to reach the specified set-point rotation speed difference.
In a further embodiment it can be provided that two or three clutches that can be actuated are actuated over two ranges. With n ranges the number of clutches can be smaller than or equal to n.
In a further embodiment it can be provided that the actual rotation speed difference from the first to the n-th range, which is delimited by the set-point rotation speed difference, is increased by a corresponding closing actuation of an increasing number of clutches which can be actuated separately, in order to reach the specified set-point rotation speed difference.
In a further embodiment it can be provided that in at least two adjacent ranges, the same number of clutches are actuated. During this the respective clutches can be actuated differently, so that individually they produce different clutch torques in such manner that, when added together, the clutch torques of the particular clutches actuated in that range remains the same or increases from the one range to the next-higher adjacent range. With two ranges, in the first range one clutch and in the second range two, three or more clutches can be actuated in the closing direction. With two ranges, in the first range two clutches and in the second range three or more clutches are actuated to close.
In a further embodiment it can be provided that in at least one of the ranges each of the clutches that can be actuated in order to reach the specified set-point rotation speed difference, is actuated to close.
In further embodiments it can be provided that of all these ranges are at least the last two ranges or the last range. With two ranges and two clutches that can be actuated in the closing direction, in the second range the two clutches that can be actuated can be closed. With two ranges and three clutches that can be actuated in the closing direction, in the second range all three controllable clutches can be closed.
In a further embodiment it can be provided that at least in the range which is closest to the set-point rotation speed difference, each clutch that can be actuated in order to reach the specified set-point rotation speed difference is actuated in the closing direction.
This range is also called the last, or the n-th range. With a total of two ranges this range then corresponds to the second range. With a total of three ranges, this range then corresponds to the third range
In a further embodiment it can be provided that at least in the range farthest away from the set-point rotation speed difference, one of the clutches that can be actuated in order to reach the specified set-point rotation speed difference is actuated to close.
This range can also be called the first range. That can be a single clutch. The said clutch can have the lowest or the highest maximum clutch torque, i.e. the lowest or the highest frictional performance of all the clutches that can be actuated to close.
In a further embodiment it can be provided that the step of applying a torque to the turbine wheel comprises at least the following part-steps: closing of the first clutch in order to apply an increasing clutch torque to the turbine wheel, until the actual rotation speed difference has reached a specified rotation speed difference; closing at least one further clutch in addition to the first clutch in order, by each of the at least one further clutch, to apply a still greater clutch torque to the turbine wheel until the actual rotation speed difference has reached the set-point rotation speed difference; adjusting the actual rotation speed difference to the set-point rotation speed difference, in that at least one of the clutches is actuated to close or open until the set-point difference is maintained over a determined time interval and within a determined tolerance range.
In a further embodiment it can be provided that after the step of applying a torque to the turbine wheel, the step of calibrating filling parameters of the converter lock-up clutch is carried out. During this the converter lock-up clutch can be closed until a “touch point” is approached, at which the set-point rotation speed difference is no longer maintained. This step can be repeated during the course of an iterative search for the optimum filling parameters, until the reduction of the set-point rotation speed difference corresponds to specified indicators.
According to a further aspect the invention relates to a control unit for carrying out the control method, such that the control unit comprises the following features:
In a further embodiment it can be provided that the control unit is integrated into an existing control unit, or that it is a separate control unit. The signal transmission and connections to the signal input and the signal output can be wired or wireless. The output signal can depend on the actual rotation speed difference and the range within which this actual rotation speed difference is located. The output signal can depend on the actual rotation speed difference, the range within which this actual rotation speed difference is located, and the number of clutches to be actuated in that range. The determination device can be a separate device, or it can be at least partially integrated in the control unit.
Furthermore, the invention relates to a transmission device incorporating the said control unit, wherein the transmission device comprises the following features:
In a further embodiment it can be provided that the hydrodynamic torque converter is connected by way of the turbine wheel on its output side to the transmission device. The hydrodynamic torque converter can comprise a guide wheel.
In addition, the invention relates to a vehicle with the transmission device for transmitting a driving force from a drive device in order to propel the vehicle.
In a further embodiment it can be provided that the hydrodynamic torque converter is connected on its input side directly or indirectly to the drive device in order to propel the vehicle.
Embodiments or features described in the context of one aspect of the invention can be combined with embodiments or features described in the context of another aspect of the invention.
The hydrodynamic torque converter 14 comprises a pump wheel 18 and a turbine wheel 20, and a converter lock-up clutch 22, which in this case can be actuated by a hydraulic disk clutch, and which has an internal pressure of up to 6 bar. The rotation speed difference An between the pump wheel 18 and the turbine wheel 20 can be determined by means of a determination device (not shown) connected to the control unit 12 for the direct or indirect determination of an actual rotation speed difference ΔnIST. The hydrodynamic torque converter 14 is connected on its input side by way of the pump wheel 18 to the drive unit for propelling the vehicle and by way of the turbine wheel on its output side to the transmission 10. Thus, the rotation speed n of the pump wheel 18 corresponds to the output-side rotation speed n of the drive unit. Consequently, the rotation speed n of the pump wheel 18 can be taken to be the rotation speed n of the drive unit. The general mode of operation of such a hydrodynamic torque converter 14 with a converter lock-up clutch 22 is already known from the prior art.
The power-split transmission 16 is connected on its input side to the turbine wheel 20 and comprises three clutches 32, 34, 36, each associated with a respective power-split shaft assembly 26, 28, 30. The clutches 32, 34, 36 associated with a power-split shaft assembly 26, 28, 30 are clutches of the transmission 16 on the input side. The clutches 32, 34, 36 are connected to a signal output 38 of the control unit 12 and can be actuated separately to close and open them, in order to apply a clutch torque MK to the turbine wheel 20 so that the rotation speed difference Δn, i.e. the slippage between the pump wheel 18 and the turbine wheel 20 changes. In this case the clutch 32 is a clutch for forward driving (KV), the clutch 34 is a clutch for reverse driving (KR) and the clutch 36 is a further clutch (K4). If each of the clutches 32, 34, 36 associated with a power-split shaft assembly 26. 28, 30 is opened, then no clutch torque MK is applied to the turbine wheel 20.
The control unit 12 is designed to carry out a control method. For that purpose the control unit 12 comprises the signal input 24 for receiving an input signal, which transmits the actual rotation speed nIST-P of the pump wheel 18 and the actual rotation speed nIST-T of the turbine wheel 20 of the hydrodynamic torque converter 14. In addition, the control unit 12 comprises the signal output 38 for emitting an output signal, which transmits the actuation commands for the simultaneous closing of at least two of the clutches 32, 34, 36. Furthermore, the control unit 12 comprises a computer unit 40 which is connected to the signal input 24 and the signal output 38 and is designed, by virtue of an input signal, to calculate an actual rotation speed difference ΔnIST between the pump wheel 18 and the turbine wheel 20 and to generate an output signal as a function of the calculated actual rotation speed difference ΔnIST.
The control method shown here is provided for large structural forms with correspondingly large manufacturing tolerances, and is carried out in the case of a stationary vehicle or a transmission correspondingly static on its output side during production, after an oil change or during the identification of inadequate shifting behavior, and comprises the following steps:
Step 1 (S1):
Opening of the converter lock-up clutch 22 and of the two clutches 32, 34 of the transmission 16, each respectively associated with a power-split shaft assembly 26, 28, which clutches are able to apply a clutch torque MK to the turbine wheel 20;
Step 2 (S2):
Rotating S2 the pump wheel 18 with a specified rotation speed n; and
Step 3 (S3):
Application S3 of a clutch torque MK to the turbine wheel 20 as a function of the actual rotation speed difference ΔnIST in order to reach a specified set-point rotation speed difference ΔnSOLL, wherein two clutches 32, 34, each respectively associated with a different power-split shaft assembly 26, 28 of the transmission 16, are actuated at the same time to close them.
The set-point rotation speed difference ΔnSOLL is in this case specified in just the same way as the two equally large ranges Δn1, Δn2 into which the set-point rotation speed difference ΔnSOLL is divided. Thus, both the first range Δn1 and the second range An2 each correspond to half the set-point rotation speed difference ½ΔnSOLL.
The first range Δn1 extends from time-point t1 to time-point t2, during which the first clutch 32 is closed in order to apply an increasing clutch torque MK to the turbine wheel 20. Time-point t2 is reached when the actual rotation speed difference ΔnIST has reached the top end of the first range Δn1 and thus at the same time the lower end of the second range Δn2 at the half rotation speed difference ½ΔnSOLL. From that time-point t2 onward the clutch torque MK applied by the first clutch 32, i.e. the frictional performance of the clutch 32, is kept constant in that the first clutch 32 is not closed or opened any farther. Instead, now in addition the second clutch 34 is closed in order to increase the clutch torque MK on the turbine wheel 20 still more. In this case the time-point t3 is reached when the actual rotation speed difference ΔnIST has reached the top end of the second range Δn2 at the set-point rotation speed difference ΔnSOLL. From time-point t3 onward, the actual rotation speed difference ΔnIST is adjusted to the set-point rotation speed difference ΔnSOLL in that only and exclusively the first clutch 32 is actuated to close or open it. As soon as the set-point rotation speed difference ΔnSOLL has been maintained over a defined time period and within a defined tolerance range, the time-point t4 has been reached. From this time-point t4 onward, in this condition a calibration process known from the prior art, for example calibration of the filling parameters of the converter lock-up clutch 22, is carried out in a subsequent Step 4 (S4). During this the converter lock-up clutch 22 is closed until a “touch point” is approached, at which the setpoint rotation speed difference ΔnSOLL is no longer maintained. When during the course of a corresponding iterative search for the optimum filling parameters the fall of the set-point rotation speed difference ΔnSOLL conforms to specified indicators, the filling is taken to be ideal.
By virtue of the division of the set-point rotation speed difference ΔnSOLL into a number of ranges Δn1, Δn2, the Step 3 (S3) can be divided into the following part-steps:
Step 3.1 (S3.1):
Closing of the first clutch 32 in order to apply an increasing clutch torque MK to the turbine wheel 20, until the actual rotation speed difference ΔnIST has reached half the set-point rotation speed difference ½ΔnSOLL;
Step 3.2 (S3.2):
Closing the second clutch 34 in addition to the first clutch 32, in order to apply a still larger clutch torque MK to the turbine wheel 20, until the actual rotation speed difference ΔnIST has reached the set-point rotation speed difference ΔnSOLL;
Step 3.3 (S3.3):
Adjustment of the actual rotation speed difference ΔnIST to the set-point rotation speed difference ΔnSOLL, in that exclusively the first clutch 32 is actuated to close it or open it, until the set-point rotation speed difference ΔnSOLL is maintained over a defined time period and within a defined tolerance range.
The condition reached in this way serves as the starting point for further steps, and thus in this case for the subsequent Step 4 (S4):
Step 4 (S4):
Calibration of filling parameters of the converter lock-up clutch 22.
Below further embodiments are described, which conform to the above-described basic principles.
According to a further embodiment it is provided that the closing process consists of an active or passive closing. In active closing the frictional performance of the clutch concerned is increased. In passive closing the frictional performance of the clutch concerned is kept constant, in that the clutch is kept closed. Correspondingly, according to a further embodiment it is provided that at least two clutches respectively associated with a different shaft assembly of the transmission are actuated in the closing direction at the same time. Opening refers to an active opening process in which the frictional performance of the clutch concerned is reduced.
According to a further embodiment it is provided that the transmission 16 comprises only two clutches 32, 34 associated with a power-split shaft assembly 26. 28 on the input side. In a further embodiment the transmission 16 comprises three - as described in the first embodiment - or more than three such clutches 32, 34, 36. In another embodiment the simultaneous closing of the at least two clutches 32, 34, 36, i.e. the clutch torque that results therefrom, is quantitatively the same or different.
According to a further embodiment it is provided that before a clutch torque MK is applied to the turbine wheel 20, the set-point rotation speed difference ΔnSOLL is divided into at least two ranges Δn1 - Δnn as described in the first embodiment. According to a further embodiment, in two Δn1, Δn2 of the at least two ranges Δn1 - Δnn a different number of clutches 32, 34 is actuated in the closing direction in order to reach the specified set-point rotation speed difference ΔnSOLL. In another embodiment a) the set-point rotation speed difference ΔnSOLL, b) the number of ranges into which the set-point rotation speed difference ΔnSOLL is divided, or c) the number of clutches actuated in each range Δnn is specified. According to a further embodiment two of the variables a), b), and c) are predetermined. In another embodiment all three variables a), b), and c) are predetermined.
According to a further embodiment the ranges Δn1 - Δnn are all the same size - as described in the first embodiment - or of different sizes. In a further embodiment the ranges Δn1 - Δnn become larger toward the set-point rotation speed difference ΔnSOLL. In another embodiment the size of a range Δnn is adapted to the maximum clutch torque of the clutches respectively actuated in it. According to a further embodiment this adaptation takes place on the basis of the lowest maximum clutch torque MK of the clutches respectively actuated therein. The maximum clutch torque MK refers to the maximum permissible frictional performance for a clutch. In a further embodiment the lowest range begins at a rotation speed difference Δn of 0. The highest range ends - as described in the first embodiment - at the set-point rotation speed difference ΔnSOLL.
According to a further embodiment the number of ranges into which the set-point rotation speed difference ΔnSOLL is divided, is smaller than or equal to a number of clutches that can be actuated separately in order to reach the specified set-point rotation speed difference ΔnSOLL. Thus, in the first embodiment two controllable clutches 32, 34 can be actuated over a range Δn2. According to a further embodiment three controllable clutches can be actuated over two ranges. In another embodiment, with n ranges the number of clutches is smaller than or equal to n.
According to a further embodiment the actual rotation speed difference ΔnIST is increased from the first range Δn1 to the last or n-th range Ann, which is limited by the set-point rotation speed difference ΔnSOLL, by correspondingly actuating an increasing number of separately controllable clutches in the closing direction in order to reach the specified set-point rotation speed difference ΔnSOLL. In a further embodiment, in at least two adjacent ranges the same number of clutches are actuated. According to another embodiment the respective clutches are actuated differently so that they individually produce a different clutch torque MK, in such manner that the sum of the clutch torques MK of the clutches actuated in the said range remains the same or increases from one range to the next-higher adjacent range. According to further embodiments, when there are two ranges Δn1, Δn2, in the first range Δn1 one clutch 32 is actuated and in the second range Δn2 two clutches 32, 34 - as described in the first embodiment - or alternatively three or more clutches are actuated to close. In another embodiment, when there are two ranges two controllable clutches can be actuated to close, and in the second range three or more clutches can be actuated to close.
According to a further embodiment, in at least one of the ranges each of the clutches that can be actuated in order to reach the specified set-point rotation speed difference ΔnSOLL is actuated to close. In further embodiments all these ranges are at least the last two ranges or the last range. According to a further embodiment, with two ranges and two clutches that can be actuated to close in the second range, both of the controllable clutches are closed. In a further embodiment, with two ranges and three clutches that can be actuated to close, in the second range all three of the controllable clutches can be closed.
According to a further embodiment, at least in the range closest to the set-point rotation speed difference ΔnSOLL, each of the clutches that can be actuated in order to reach the specified set-point rotation speed difference ΔnSOLL is actuated to close. This range is also called the last or the n-th range. With a total of two ranges Δn1, Δn2, this range Δnn then corresponds to the second range Δn2. With a total of three ranges the said range then corresponds to the third range, etc.
In a further embodiment, at least in the range which is farthest away from the set-point rotation speed difference ΔnSOLL, one clutch 32 of those clutches which can be actuated in order to reach the specified set-point rotation speed difference ΔnSOLL is actuated to close. This range is also called the first range Δn1. According to a further embodiment, the said clutch 32 has the lowest or the highest maximum clutch torque MK, i.e. the lowest or the highest maximum frictional performance of all the clutches that can be actuated to close.
According to a further embodiment the hydrodynamic torque converter comprises a guide wheel.
In a further embodiment, the hydrodynamic torque converter is connected by way of the pump wheel on its input side, directly or indirectly, for example via a further gear system, to the drive device for propelling the vehicle.
According to a further embodiment, the adjustment (S3.3) of the actual rotation speed difference ΔnIST to the set-point rotation speed difference ΔnSOLL takes place in that at least one of the clutches, for example at least the first/earliest actuated clutch or at least the last/most-recently actuated clutch, is actuated to close or to open, until the set-point rotation speed difference ΔnSOLL is maintained over a defined time period and within a defined tolerance range.
Thus, the invention provides for a division of the clutch torque MK required in order to reach a set-point rotation speed difference ΔnSOLL between at least two clutches. In that way, instead of actuating a single clutch up to its maximum frictional performance, the frictional performance can be divided between two or more clutches, which increases the life of the individual clutches and enables a lastingly reliable calibration of the converter lock-up clutch 22.
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| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 200 531.7 | Jan 2022 | DE | national |
