Method for determining a rapid filling time for a filling process of two directional clutches of a transmission of a vehicle drive train
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- ZF FRIEDRICHSHAFEN AG
- Filing Date
- 2017-06-30
- Publication Date
- 2026-07-09
AI Technical Summary
Current methods for determining the filling time of directional clutches in vehicle transmissions are imprecise, leading to under-filled or over-filled clutches that can cause premature failure and reduce reversing quality, necessitating time-consuming manual adjustments and varying software versions.
A method to determine the exact rapid filling time of directional clutches by adjusting the quick filling time based on the clutch's operating state during reversing processes, using automatic calibration and boundary conditions to ensure optimal clutch engagement, thereby reducing manual tuning and software variations.
This method enhances reversing quality and extends clutch lifespan by precisely adjusting filling times, eliminating manual adjustments and software inconsistencies, and allowing fully automatic operation without driver influence.
Smart Images
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Abstract
Description
[0001] The invention relates to a method for determining a rapid filling time of a filling process of two direction-of-travel clutches of a transmission of a vehicle drive train according to the type defined in more detail in the preamble of claim 1.
[0002] In principle, filling processes for directional clutches, known from practical experience and comprising a rapid filling phase and a subsequent equalization phase, are carried out in such a way that the engaging directional clutch has a target operating state at the end of its filling process. Ideally, the transmission capacity of the engaging directional clutch in the target operating state is just zero, and increasing the actuating force in the closing direction of the directional clutch from the target operating state results in an immediate increase in the transmission capacity of the directional clutch.
[0003] A so-called underfilled directional coupling exists when the directional coupling only reaches its target operating state after the filling process is complete, and load transfer or build-up by the coupling to be engaged does not begin at the requested time. In contrast, a so-called overfilled directional coupling is assumed when the coupling to be engaged already has a transmission capacity greater than zero before the end of the filling process, and load transfer or build-up by the coupling to be engaged occurs before a desired or defined point in time for a reversing operation.
[0004] During a requested change of direction, or a so-called reversing operation, in which the requested direction of travel is achieved via a slipping reversing clutch and a reduction of the differential speed in the area of the engaged reversing clutch, under- or over-filled reversing clutches, as well as fluctuating actuation pressures of the reversing clutches, negatively affect the output speed and thus the reversing efficiency. Furthermore, under- or over-filled reversing clutches can suffer irreversible damage during a reversing operation, leading to premature failure.
[0005] To achieve sufficient reversing performance, the filling parameters of the direction-of-travel couplings are currently adjusted manually, which is very time-consuming. This procedure also results in different software versions with different coupling filling parameters being used in the current series, causing a very high administrative and documentation effort.
[0006] Furthermore, it is known to adjust the filling of direction-of-travel clutches in hydrodynamic or power-split transmissions by means of automatic calibration of the direction-of-travel clutches. The calibration specifically determines an offset for the rapid filling time of a direction-of-travel clutch filling process, which is then used to adjust the rapid filling time. Additionally, a slip point of the direction-of-travel clutches and the corresponding current value of an electro-hydraulic pressure regulator are assigned to a theoretical slip pressure. Using this method, the entire current-pressure characteristics of the electro-hydraulic pressure regulators associated with the direction-of-travel clutches are shifted to an extent that improves the filling of the direction-of-travel clutches.
[0007] In the calibration procedure known from practical experience, a directional clutch is pressurized with approximately 4 bar actuation pressure, and this pressure is maintained for a defined operating time until a response is detected in the differential rotational speed of the directional clutch to be engaged. This time is then recorded, and an offset value is subtracted. The result is scaled to the current rapid filling pressure level of approximately 10 bar and subsequently represents the duration of the rapid filling phase of the directional clutch to be engaged.
[0008] However, this approach is inaccurate and leads to the disadvantages explained in more detail above.
[0009] The present invention is therefore based on the objective of providing a method by which an exact determination of the rapid filling time of a filling process of a directional coupling is possible in order to be able to carry out reversing operations with a desired high reversing quality and to be able to operate directional couplings over a long service life.
[0010] In the inventive method for determining a rapid filling time for a filling process of two direction-of-travel clutches of a vehicle drivetrain transmission, which are engaged or disengaged from the power flow of the vehicle drivetrain during a requested reversing operation of the vehicle starting from a first direction of travel in the opposite direction, the direction-of-travel clutches each have a target operating state at the end of the filling process. Upon reaching the target operating state, the transmission capacity of the respective direction-of-travel clutch being engaged is zero. Additionally, increasing the actuating force from the target operating state of the direction-of-travel clutch being engaged results in an immediate increase in the transmission capacity of that clutch.
[0011] According to the invention, the fully emptied, deactivated, and operatively connected directional clutch, which is connected to a transmission input shaft, is engaged in the power flow during successive reversing operations when the power flow is interrupted in the transmission area between the transmission input shaft and a transmission output shaft. The engaged directional clutch is then deactivated from the power flow. The rapid filling time of the filling process for the directional clutch engaged in the power flow during a given reversing operation is reduced by an offset value if it is detected that the directional clutch to be engaged has reached its target operating state before the filling process is complete and is therefore overfilled.In contrast, the rapid filling time of the filling process of the direction-of-travel clutch that is switched into the power flow during a considered reversing process is increased by an offset value if the direction-of-travel clutch to be switched on only reaches the target operating state after the filling process has finished.
[0012] The inventive method reduces the variations and shortcomings of conventional calibration methods and easily avoids manual adjustments or differing software versions related to clutch filling. This is achieved, among other things, by determining the exact rapid filling time of an engaging directional clutch during actual reversing operations, unlike the conventional method. Furthermore, the inventive method can be implemented as a fully automatic calibrated mode that can be carried out without any input from the driver of the vehicle equipped with the powertrain.
[0013] In addition, it is possible for the driver to trigger the inventive method via a control panel, whereby the inventive procedure can also be activated via a so-called CAN message.
[0014] In addition, the inventive method allows for the easy implementation of manual adjustment and the calibration of the direction-of-travel couplings, as known from practical experience, into existing vehicle systems. The inventive approach utilizes existing evaluation methods that determine, at the end of a reversing process, whether the engaging direction-of-travel coupling has reached the target operating state to the specified extent precisely at the end of the filling process, or whether it already exhibits the target operating state before or after the end of the filling process. Based on this, it is possible, with minimal effort, to continue using the current filling parameters unchanged or to initiate appropriate measures that improve the filling behavior of an engaging direction-of-travel coupling to the desired extent.
[0015] To avoid incorrect adjustments to the rapid filling time, further advantageous variants of the inventive method, which can be implemented with minimal control effort, stipulate that certain boundary conditions must be met before the inventive method is carried out. It is possible to activate the method upon fulfillment of a single boundary condition or to execute the method only when a combination of several boundary conditions is met.
[0016] The reversing process is only carried out when the rotational speed of the transmission output shaft is less than a threshold value and / or when the operating temperature of the transmission is greater than a threshold value. Additionally or alternatively, in further advantageous variants of the method according to the invention, the reversing process is carried out when defined rotational speeds of the transmission input shaft and / or predefined operating temperatures of the transmission are present.
[0017] Additionally, it may also be provided that the reversing operations are only carried out when the parking brake of the vehicle equipped with the vehicle drivetrain is closed, as this ensures that the reversing takes place when the vehicle is stationary and that driver influence on the reversing operations is reliably avoided.
[0018] Furthermore, it may also be provided that the reversing processes only occur when a high pressure is present in a high pressure area of a hydrostatically designed variator of the continuously variable transmission, and that the value within the permissible range is not exceeded.
[0019] If the rapid filling time of the filling phase of the direction-of-travel coupling to be engaged during the execution of a requested reversing corresponds to the rapid filling time that was determined based on the behavior of the direction-of-travel coupling to be engaged during the reversing preceding the reversing to be carried out, during which the direction-of-travel coupling to be engaged was also engaged, the value of the rapid filling time that ensures a high reversing quality is determined iteratively within short operating times.
[0020] If the rapid filling time of the filling phase of the respective direction-of-travel coupling to be activated is only changed by the offset value when the respective direction-of-travel coupling to be activated has the target operating state before or after the filling process has been completed during at least two successive reversing operations of the same direction-of-travel coupling, misadjustments are avoided in a simple way.
[0021] If the offset value is smaller than the cycle time of a control unit of the transmission, incorrect adjustments to the quick-fill time are also avoided with minimal effort.
[0022] In a further advantageous embodiment of the inventive method, the number of reversals after which the rapid filling time of the filling phase of the respective directional coupling is reduced by the offset value is smaller than the number of reversals after which the rapid filling time is increased by the offset value. This allows for a weighted approach to the filling of the directional coupling to be implemented with minimal effort. For example, such weighting means that the detection of an overfilled directional coupling immediately leads to a correction of the rapid filling time, while the detection of an underfilled directional coupling, for example, only triggers a correction of the rapid filling time after three detections.
[0023] If, during a reversing process, both an overfilled and an overfilled directional coupling are detected, the detection of an overfilled directional coupling is deactivated in a further advantageous variant of the inventive method and the rapid filling time is not changed to the extent in accordance with the invention.
[0024] In a further advantageous embodiment of the method according to the invention, a predefined number of reversing operations are performed for predefined speeds of the transmission input shaft. In this case, the rapid filling time for the respective directional clutch to be engaged is not adjusted after the last reversing operation at the respective defined speed of the transmission input shaft, even if the input shaft requests an adjustment corresponding to the previous reversing operation. This ensures, in a simple manner, that an erroneous adjustment of the rapid filling time, which would no longer be verifiable via a further reversing operation, is avoided.
[0025] In a further advantageous embodiment of the inventive method, the reversals for a defined speed of the transmission input shaft are terminated before the predefined number is reached if, during at least two successive reversals, during which the same direction-of-travel clutch is engaged, it is detected that the direction-of-travel clutch to be engaged has reached its target operating state at the end of the filling phase. This approach offers the advantage that the rapid filling time can be adjusted within short operating times.
[0026] In a further advantageous embodiment of the method according to the invention, the reversals are performed for a defined speed of the transmission input shaft until an adjustment of the rapid filling time is no longer necessary for a defined number of reversals. In order to limit the duration of such a procedure, only a maximum number of reversals are performed for a predefined speed of the transmission input shaft.
[0027] Both the features specified in the patent claims and the features specified in the following embodiment of the invention are each suitable, either individually or in any combination with one another, to further develop the invention.
[0028] Further advantages and beneficial developments of the invention will become apparent from the patent claims and the exemplary embodiment described in principle with reference to the drawing.
[0029] It shows: Fig. 1 a highly schematic block diagram representation of a vehicle powertrain with a continuously variable transmission; Fig. 2 a block diagram of a variant of the inventive procedure for determining a rapid filling phase of a filling process of direction couplings of the vehicle drive train according to Fig. 1; and Fig. 3a to Fig. 3e several curves of different operating parameters of the vehicle powertrain during the execution of the procedure according to Fig. 2.
[0030] Fig. Figure 1 shows a highly schematic representation of a vehicle powertrain. 1 with a drive motor 2, with a continuously variable power-split transmission 3 and with a drive 4 The continuously variable transmission 3 includes a variator designed as a hydrostatic drive 5 as well as two hydraulically actuated friction-locked direction-of-travel couplings 6 , 7 The direction-of-travel couplings 6 and 7 are during requested reversing operations of a vehicle's powertrain 1 The vehicle's power flow, starting from a first direction of travel and moving towards an opposite direction of travel, enters the vehicle's drivetrain. 1 switched on or switched off from the power flow.
[0031] The direction-of-travel couplings 6 , 7At the end of a filling process, which includes a rapid filling phase and a filling equalization phase, ideally each has a target operating state in which their transmission capabilities are zero and from which an increase in the actuating forces results in an immediate increase in the transmission capabilities.
[0032] The respective direction-of-travel coupling is selected. 6 or 7 During the rapid filling phase of the filling process, the filling process is carried out quickly for a defined rapid filling time with a defined rapid filling pressure, i.e., with a rapid filling pulse.
[0033] tsf6 or tsf7 The rapid filling phase is followed by a so-called filling compensation phase, during which the respective direction-of-travel clutch to be switched on is supplied with a filling compensation pressure level that is reduced compared to the rapid filling pressure level for a filling compensation time, until the direction-of-travel clutch to be switched on has the desired target operating state.
[0034] If, during a reversing process, it is detected that the respective direction-of-travel clutch to be engaged is not yet engaged 6 or 7 If the target operating state is reached even before the end of its filling process, i.e., at the end of the filling equalization phase, an overly full directional clutch is detected. In contrast, an underly empty directional clutch is detected. 6 or 7 determined when, during a reversing operation, it is determined that the directional clutch to be engaged 6 or 7only after the filling process has been completed does it reach the target operating state.
[0035] The evaluation of reversing processes described above is used to determine the current rapid filling time of the filling process of the switching-on directional clutch. 6 or 7 to adjust the reversibility quality to an extent that increases it. For this purpose, a Fig. 2 simplified procedures were carried out.
[0036] Before discussing the procedure according to Fig. 2. Before a check and adjustment of the rapid fill time is performed, several defined boundary conditions are first checked. The boundary conditions represent output signals from several boundary condition blocks. RB1 until RBx represent the input values of a test block PB are in the test block PB Among other things, it will be checked whether this is compatible with the vehicle's powertrain. 1The vehicle is stationary, or at least the output shaft is rotating. 4 smaller than its threshold value. Furthermore, it is verified whether the operating temperature of the power split gearbox is within the specified range. 3 or an oil temperature of the oil sump of the power split transmission 3 greater than its threshold value. Additionally, it is checked whether the engine speed is within a specific range and whether the vehicle's parking brake is engaged. If the aforementioned conditions are met, a neutral operating state of the power-split transmission is selected via a vehicle-side drive switch. 3 requested, to which the power flow in the area of the power split transmission between a transmission input shaft and a transmission output shaft is interrupted, and there is a high pressure of a high pressure area of the hydrostatic drive. 5Within a valid range of values, the procedure described in more detail below is used to determine a rapid filling time for a filling process of the direction-of-travel clutch that ensures high reversing quality. 6 or 7 carried out.
[0037] During the procedure for determining the rapid filling time, so-called standstill reversals are performed at defined intervals in the power split gearbox. 3 This is triggered by a software-based, so-called artificial toggling of the direction switch. This initiates a normal series of several successive reversals to assess the filling level of the direction clutch being engaged in each reversal. 6 or 7to be able to carry out this. It is important to maintain a specific time interval between successive reversals in order to ensure that the reversal is performed with a fully emptied, engageable directional clutch each time. 6 or 7 to be able to carry out this. This allows, with minimal effort, a direct correlation to be established between the evaluation of the reversing and the rapid filling time of the engaging directional clutch required to achieve a high reversing quality. 6 or 7 manufactureable.
[0038] To obtain the most comprehensive characteristic curve of the rapid filling time, which depends, among other things, on the speed of the drive motor 2 and the operating temperature of the power split gearbox 3 is the respective direction-of-travel couplings to be switched on 6 or 7To be able to adapt, the reversals are performed at different speeds of the drive machine. 2 and preferably also at different operating temperatures of the power split gearbox 3 carried out.
[0039] If the boundary conditions described above are met, the test block indicates PB a corresponding signal to an evaluation block BB Additionally, the rating block receives BB also a request signal for clutch calibration by means of standstill reversals from a release block AB .
[0040] This is in the area of the evaluation block. BB The determined assessment result, indicating whether the clutch to be engaged during the standstill reversal was too full or too empty, is transferred to the calibration blocks. KB6 or KB7 the direction-of-travel couplings 6 or 7each provided as an input variable.
[0041] In the area of calibration blocks KB6 and KB7 The rapid filling time of the filling process of the direction-of-travel coupling is determined in each case. 6 or 7 by means of the following representations according to Fig. 3a to Fig. calibrated according to the procedure explained in more detail in section 3e.
[0042] In Fig. 3a There are three different motor speed classes over the operating time t n2A , n2B and n2C schematically represented, where the speed value of the engine speed class n2A equal to 1500 rpm, while the speed value of the second engine speed class n2B equal to 1200 rpm and the speed value of the third engine speed class n2C 1800 rpm. The specified speed values represent an exemplary embodiment; different speed values are also possible in other embodiments. For each of the three motor speed classes n2A until n2C will be according to Fig. 3b cyclically successive reversals starting from a forward direction of travel in the direction of a reverse direction of travel of a vehicle drive train 1 The vehicle's movement is triggered, a process also known as toggling. The vertical portion of the rectangular curve corresponds to the following: Fig. 3b at the times T1 until T16 the actual reversal, while the respective horizontal areas of the rectangular curve according to Fig. 3b between the times T 1 until T16 represent the waiting times between the individual reversals.
[0043] For each vertical section, the reversal is evaluated to the extent described above, and it is determined whether the switching-on direction coupling is required. 6 or 7 was too full or too empty. This refers to the situation at the time. T1 requested reversal starting from the forward direction of travel in the direction of reverse travel requires the directional coupling to be engaged. 7 deemed too crowded, which is why in Fig. 3c at the time T1 one above the time axis t The upward-pointing column is drawn. During the time T2 The requested reversal from the reverse direction towards the forward direction requires neither an overly full nor an overly empty directional clutch to be engaged. 6 via the rating block BB It has been recognized, which is why at the time T2 in Fig. 3c no column is shown. A subsequent one and at the time T3 The requested reversal, starting from the forward direction of travel and moving towards the reverse direction, in turn results in the evaluation block BB a determination of a fully engaged directional coupling 7 , which is why there is a column above the time axis in Fig. 3c is marked.
[0044] During the at the time T4 During the further reversing process, starting from the reverse direction and moving towards the forward direction, an empty, engageable direction-of-travel clutch is used. 6 determined why a below the time axis t horizontal and downward-pointing column in Fig. 3c is entered. The respective assessment results for the assessment block are shown. BB representative columns of the direction-of-travel coupling 7 in Fig. 3c under the reference number BB7 more precisely marked, while the evaluation result for the direction-of-travel coupling 6 each representing column under the reference sign BB6 are more precisely marked.
[0045] Since during the time T1 The reverse operation resulted in an excessively full engagement of the directional clutch. 7 was detected at the time T1 the quick fill time tsf7( n2A ) the direction-of-travel coupling 7 the first engine speed class n2A Starting from a base value, the value is reduced by a defined offset value. Additionally, the reversal occurs at time... T3 , to which the direction-of-travel coupling 7 again represents the switching direction coupling, with which at the time T1 Fast fill time reduced by the offset value tsf7( n2A ) of the first engine speed class n2A carried out. Since during the reversal at the time T3 again, an excessively full directional clutch 7 When detected, the quick fill time tsf7( n2A ) the direction-of-travel coupling 7 the first engine speed class n2A at the time T3 again reduced by the offset value and further reversal at time T5 with the newly adjusted value of the quick fill time tsf7( n2A ) carried out.
[0046] During the time T5 reversal performed within the first engine speed class n2A However, if the directional coupling is too empty, it will need to be engaged. 7 determined why the quick fill time tsf7( n2A ) in which in Fig. 3D depicted scope at the time T5 which is then increased by the offset value. Since at the time T5The reversal performed is the last reversal of the engine speed class. n2A is, to which the direction-of-travel coupling 7 represents the directional coupling to be switched on, and the evaluation result of the evaluation block BB from the valuation result of the reversal at the time T3 If it deviates, the quick fill time tsf7( n2A ) at the time T5 corrected to the extent shown.
[0047] Since the directional coupling to be switched on 6 during the time T4 If the reversal performed is deemed too empty, the quick fill time tsf6( n2A ) of the first engine speed class n2A in which Fig. 3e scope shown at the time T4 Starting from the initial value, the offset value is increased. In contrast, the reversal at time triggers the T6 via the rating block BB The evaluation of the directional coupling to be engaged was carried out. 6 as too empty, no adjustment of the quick fill time tsf7( n2A ). This results from the fact that the reversal occurred at the time T6 the last reversal within the first engine speed class n2A is and to the same extent as the reversal at the time T4 a reduction of the rapid fill time tsf6 by the threshold value is requested. This approach easily prevents mismatches in the rapid fill times tsf7( n2A ), tsf7( n2B ), tsf7( n2C ) and tsf6( n2A ), tsf6( n2B ), tsf6( n2C ) at the end of an engine speed class n2A until n2C reached.
[0048] During the second engine speed class n2B will again be at the following times T7 until T14Further reversals between forward and reverse travel are carried out to the extent described above. These reversals occur at the following times: T7 and T9 Each one is a fully engaged directional coupling. 7 determined while at the time T8 a fully engaged directional clutch 6 is determined. In contrast, the rating block BB at the time T10 a directional coupling that is too empty 6 out of.
[0049] The evaluation results of the evaluation block BB at those times T8 and T10 This in turn causes the quick fill time tsf6( n2B ) of the second engine speed class n2B based on the standard rapid filling time of the second engine speed class n2B at the time T8 reduced by the offset value and at the time T10 is increased by the offset value.
[0050] During the third engine speed class n2C will only be at the time T15 a fully engaged directional clutch 7 determined why the quick fill time tsf7( n2C ) of the third engine speed class n2C based on the standard quick-fill time at the time T15 is reduced by the offset value.
[0051] Since the directional coupling needs to be switched on 6 during the third engine speed class n2C in which Fig. 3a to Fig. If no assessment is too full or too empty during the period shown (3e), the quick fill time tsf6( remains. n2C ) of the third engine speed class n2C based on the value of the standard quick-fill time.
[0052] The initial values of the rapid fill times tsf7( n2A ), tsf7( n2B ), tsf7( n2C ) and tsf6( n2A ), tsf6( n2B ), tsf6( n2C ) are predefined values that apply to all power-split transmissions 3 a gearbox series and for all engine speed classes n2A until n2C Depending on the specific application, the rules may be defined uniformly or differently from one another.
[0053] The respective ones for the engine speed classes n2A until n2C determined and, if necessary, adjusted rapid filling times tsf7( n2A ), tsf7( n2B ), tsf7( n2C ) and tsf6( n2A ), tsf6( n2B ), tsf6( n2C ) are used to adjust the characteristic map of the fast filling times tsf7( n2A ), tsf7( n2B ), tsf7( n2C ) and tsf6( n2A ), tsf6( n2B ), tsf6( n2C ) are used. Then the direction-of-travel couplings are used. 6 and 7In operation, taking into account the adapted characteristic map, during real reversing processes starting from the forward direction of travel in the direction of reverse travel or in the opposite direction, in order to positively influence the driving behavior of a vehicle or the reversing quality of reversing operations.
[0054] The clutch calibration described above, using standstill reversals, replaces the manual hand adjustment and clutch calibration in the vehicle known from practice, by being based on the evaluation of the evaluation block. BB decides whether the filling of the coupling or the directional couplings 6 and 7 The desired scope has been achieved, whereby, depending on the assessment, measures will be initiated as needed to improve the filling behavior of the direction-of-travel couplings. 6 and 7 to improve.
[0055] Calibration of the direction-of-travel couplings 6and 7 The aforementioned standstill reversals can be used as a calibration mode, which is fully automatic and can be implemented without any driver intervention.
[0056] In principle, a preferred variant of the method according to the invention comprises the following process steps: - Start of the procedure; - Engaging the directional clutch to be activated and setting the direction switch to forward direction; - Engine setting to an average value of the first engine speed class n2A of the characteristic curve of the rapid filling time, where the average value is typically equal to 1500 rpm; - alternately perform a certain number of reversals from forward to backward and from backward to forward; - Engine setting to an average value of the next engine speed class n2B of the characteristic curve of the fast filling time, where the average value is typically equal to 1200 rpm; - alternately perform a certain number of reversals from forward to backward and from backward to forward; - Engine setting to an average value of the last engine speed class n2C of the characteristic curve of the fast filling time, where the average value is typically equal to 1800 rpm; - again, alternately perform a certain number of reversals from forward to backward and from backward to forward.
[0057] During the preferred variant of the procedure, thus for each engine speed class n2A until n2C a certain number of reversals were performed, and the filling of the directional coupling to be engaged took place in each instance. 6 or 7assessed. Upon detection of an excessively full or empty directional control clutch, the system determines whether it needs to be engaged. 6 or 7 The rapid filling time tsf6 or tsf7 of the respective direction-of-travel coupling to be activated can be 6 or 7 directly adjusted by an offset value of the fast fill time.
[0058] The subsequent reversal can now be evaluated using the corrected rapid filling time tsf6 or tsf7, thus determining the optimal value of the rapid filling time within short operating times. t can be determined iteratively.
[0059] Alternatively, the option to engage the direction-of-travel couplings can also be applied only after a certain number of couplings have been rated as too full or too empty. 6 or 7An adjustment of the respective rapid filling time tsf6 or tsf7 by an offset value is performed. The increment of the rapid filling offset value is, for example, parametrically adjustable and should advantageously be smaller than the cycle time of the control unit of the power-split transmission. 3 be.
[0060] Furthermore, it is also possible to weight the filling of the respective direction-of-travel coupling to be activated. 6 or 7 to do this, for example by detecting an excessively full directional clutch that needs to be engaged. 6 or 7 This immediately leads to a correction and the detection of an empty, engageable directional coupling. 6 or 7 for example, it only triggers after a correction has been detected three times.
[0061] Furthermore, there is also the possibility that the detection of an empty, switchable direction-of-travel coupling 6 or 7 is deactivated and no change to the quick-fill time tsf6 or tsf7 is triggered if, during a reversing operation, first an overfilled and then an overfilled direction-of-travel clutch is engaged. 6 or 7 is recognized.
[0062] In principle, after a correction of the rapid filling time, reversals are further evaluated and the rapid filling time tsf6 or tsf7 of the respective directional coupling to be switched on is determined. 6 or 7 further corrections or counter-corrections are made as long as the maximum number of reversals is not exceeded in each engine speed class. n2A until n2C has not yet been achieved.
[0063] One special feature is that the last reversal occurs in each engine speed class. n2A until n2C does not trigger any correction and is used solely as an evaluation or correction step. After the last reversal within one of the engine speed classes. n2A until n2C Corrections will therefore only be made if the filling level is assessed via the filling block. BB the respective direction-of-travel coupling 6 or 7 the preceding evaluation of the evaluation block BB in the same engine speed class n2A until n2C was the opposite. This occurs after the penultimate reversal of the relevant engine speed class. n2A until n2C , for which a directional coupling that is too empty needs to be engaged 6 or 7 If the correction detects and calculates a positive quick-fill offset for the quick-fill time tsf6 or tsf7, then the quick-fill time tsf6 or tsf7 after the last reversal in an engine speed class n2A until n2C Only corrected if an excessively full directional clutch is engaged again. 6 or 7 This is detected because the previous correction of the penultimate reversal is then reversed. A clutch that is too loose is detected in the last reversal of the respective engine speed class. n2A until n2C In this described variant of the procedure, no further correction is triggered, as no further verification of the correction made follows, nor is any such verification possible.
[0064] Furthermore, there is also the possibility that the entire calibration can be performed at different operating temperatures of the power split gearbox. 3 or of the oil sump is repeated, thus determining and calibrating not only an engine speed-dependent, but also a temperature-dependent filling map of the direction-of-travel clutches.
[0065] In the previously described variants of calibrating the rapid filling process using standstill reversals, a configurable number of reversals are performed. Afterwards, the system automatically switches to the next engine speed class. n2A until n2C changed.
[0066] Another option is to move directly to the next engine speed class. n2A until n2C to skip ahead if the respective direction-of-travel clutch to be engaged 6 or 7For example, if no excessively full or empty reversing clutch is detected twice in succession, this offers the advantage that the adjustment of the rapid filling time tsf6 or tsf7 can be carried out within shorter operating times. This results from the fact that the predefined number of reversals for the selected engine speed class does not have to be performed before switching to the next engine speed class.
[0067] In a further variant of the inventive procedure, it may also be provided that reversing within one of the engine speed classes n2A until n2C to be carried out, for example for two consecutive reversing operations, in which the same direction-of-travel clutch is the direction-of-travel clutch to be engaged, due to the filling evaluation via the evaluation block BB No correction of the rapid fill time tsf6 or tsf7 is triggered. However, the number of reversals within an engine speed class is relevant for this. n2A until n2C to limit each to a maximum number to ensure that the operating time until switching to the next engine speed class does not become infinitely long.
[0068] In general, the method according to the invention is also suitable for other friction-fit switching elements, such as lamellar switching elements or the like, which are involved, for example, in gear ratio changes or are intended to represent a connection between two rotatable components or between a rotatable component and a housing-fixed component. Reference symbol list 1 Vehicle powertrain 2 Drive machine 3 Continuously variable power-split transmission 4 Drive 5 variator 6, 7 Directional coupling AB trigger block AB trigger block BB rating block BB rating block KB6, KB7 Calibration block n2A, n2B, n2C engine speed class PB test block RB1 to RBx boundary condition block t operating time T1 to T16 discrete time point tsf6 Rapid filling time of the switchable direction-of-travel clutch 6 tsf7 Rapid filling time of the switchable direction-of-travel clutch 7
Claims
[1] Method for determining a rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) of a filling process of two direction-of-travel clutches (6, 7) of a transmission (3) of a vehicle drive train (1) of a vehicle, which are engaged or disengaged from the power flow of the vehicle drive train (1) during a requested reversing process of the vehicle starting from a first direction of travel in the direction of an opposite direction of travel, wherein the direction-of-travel clutches (6, 7) each have a target operating state at the end of the filling process in which their transmission capacity is zero and from which an increase in the actuating force causes an immediate increase in the transmission capacity, characterized by, that the fully emptied, deactivated, and operatively connected direction-of-travel clutch (6 or 7) is engaged in the power flow during successive reversing operations when the power flow is interrupted in the area of the transmission (3) between a transmission input shaft and a transmission output shaft, and that the engaged direction-of-travel clutch (7 or 6) is deactivated from the power flow, wherein the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) of the filling process of the direction-of-travel clutch (6 or 7) to be engaged in the power flow during a considered reversing operation is reduced by an offset value when it is detected that the direction-of-travel clutch (6 or 7) to be engaged has reached the target operating state before the filling process is completed, and wherein the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B),The filling process of the direction-of-travel clutch (6 or 7) to be engaged during a considered reversing process is increased by an offset value if the direction-of-travel clutch (6 or 7) to be engaged only reaches the target operating state after the filling process has finished. [2] Method according to claim 1, characterized by , that the reversing operations are carried out when the rotational speed of the transmission output shaft is less than a threshold value. [3] Method according to claim 1 or 2, characterized by , that the reversing operations are carried out when the operating temperature of the gearbox (3) is greater than a threshold value. [4] Method according to any one of claims 1 to 3, characterized by that the reversing operations are carried out when defined speeds of the transmission input shaft are present and / or when predefined operating temperatures of the transmission are present. [5] Method according to any one of claims 1 to 4, characterized by that the reversing operations are carried out with the parking brake engaged. [6] Method according to any one of claims 1 to 5, characterized by , that the reversing processes are carried out within a permissible range of values when a high pressure is present in a high pressure area of a variator (5) designed as a hydrostatic transmission of the transmission (3) designed as a continuously variable power split transmission. [7] Method according to any one of claims 1 to 6, characterized by, that the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) of the filling phase of the direction coupling (6, 7) to be switched on during the execution of a requested reversing corresponds to the rapid filling time that was determined on the basis of the behavior of the direction coupling (6, 7) to be switched on during the reversing preceding the reversing to be carried out, during which the direction coupling (6, 7) to be switched on was also switched on. [8] Method according to any one of claims 1 to 7, characterized by, that the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) of the filling phase of the respective direction-of-travel coupling (6 or 7) is only changed by the offset value when the respective direction-of-travel coupling (6 or 7) has the target operating state before or after the filling process during at least two successive reversing operations. [9] Method according to any one of claims 1 to 8, characterized by , that the offset value is less than a cycle time of a control unit of the transmission (3). [10] Method according to any one of claims 1 to 9, characterized by, that the number of reversals after which the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) of the filling phase of the respective directional coupling (6 or 7) to be switched on is reduced by the offset value, is less than the number of reversals after which the rapid filling time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) is increased by the offset value. [11] Method according to any one of claims 1 to 10, characterized by , that the determination of the target operating state after the filling process of the directional coupling (6, 7) to be engaged is omitted if, during a reversing process, it is recognized that the directional coupling (6 or 7) to be engaged has reached the target operating state both before and after the filling process. [12] Method according to any one of claims 1 to 11, characterized by, that for predefined speeds of the transmission input shaft a predefined number of reversing operations are carried out, whereby an adjustment of the quick-fill time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) for the respective direction-of-travel clutch (6 or 7) to be engaged is omitted after the respective last reversing operation with the respective defined speed of the transmission input shaft, if this requests an adjustment corresponding to the adjustment of the previous reversing. [13] Method according to any one of claims 1 to 12, characterized by, that the reversals for a defined speed of the transmission input shaft are terminated before reaching the predefined number if, during at least two successive reversals, during which the same direction-of-travel clutch (6 or 7) is engaged, it is detected that the direction-of-travel clutch (6 or 7) to be engaged has reached the target operating state at the end of the filling phase. [14] Method according to any one of claims 1 to 13, characterized by , that the reversals for a defined speed of the transmission input shaft are performed until an adjustment of the quick fill time (tsf7(n2A), tsf7(n2B), tsf7(n2C) and tsf6(n2A), tsf6(n2B), tsf6(n2C)) is omitted for a defined number of reversals, whereby only a maximum number of reversals are performed for a predefined speed of the transmission input shaft.