MONITORING A HYDRODYNAMIC CLUTCH

Abstract

A hydrodynamic clutch having an input side and an output side, the rotational motions of which are coupled to one another with a hydraulic fluid. A method for determining the degree of filling of the hydrodynamic clutch with fluid including steps of periodically sensing a fluid temperature of the hydraulic fluid, determining the thermal output supplied to the clutch on the basis of the temperature, determining a lambda value on the basis of the thermal output and determining the degree of filling on the basis of the lambda value.

Claims

1. A method for determining a fill level of a hydrodynamic clutch with a hydraulic fluid, the clutch including an input side and an output side, rotational motions of the input side and the output side being coupled to one another by the hydraulic fluid, the method comprising the steps of: periodical sensing of a fluid temperature of the hydraulic fluid; determining a thermal output supplied to the clutch using the fluid temperature; determining a lambda value using the thermal output; and determining the fill level using the lambda value.

2. The method according to claim 1, wherein the method includes the step of determining a power supplied to the clutch, the step of determining the power supplied to the clutch including the sub-steps of: determining a maximum permissible temperature of the clutch; determining an ambient temperature of an area surrounding the clutch; and determining a power that is being transferred via the clutch using the fluid temperature and the ambient temperature.

3. The method according to claim 2, wherein the method includes the step of determining a remaining life span of the hydraulic fluid, the step of determining the remaining life span of the hydraulic fluid including: determining loads on the hydraulic fluid using the fluid temperature and the ambient temperature; determining a sum of the loads; and determining the remaining life span using the sum.

4. The method according to claim 1, wherein the method includes the step of determining a remaining life span of an antifriction bearing for mounting of the input side relative to the output side, the step of determining the remaining life span of the antifriction bearing including the sub-steps of: determining loads on the antifriction bearing using the fluid temperature; determining a sum of the loads; and determining the remaining life span using the sum.

5. The method according to claim 4, wherein a frequency of starts is used to determine the remaining life span of the antifriction bearing.

6. The method according to claim 4, wherein slippage between the input side and the output side is used to determine the remaining life span of the antifriction bearing.

7. The method according to claim 1, wherein the method is carried out using a computer program running on a processor or stored on a computer-readable data medium having a program code.

8. A control unit for determining an operating status of a hydrodynamic clutch, having an input side and an output side, rotational motions of the input side and the output side being coupled to one another by a hydraulic fluid, the control unit comprising: an interface for connecting with a temperature sensor equipped for periodic sensing of a temperature of the hydraulic fluid; and a processor arranged for determining a thermal output supplied to the clutch using the temperature of the hydraulic fluid, determining a lambda value using the thermal output, and determining a fill level using the lambda value.

9. A clutch system comprising: a hydrodynamic clutch having an input side and an output side, rotational motions of the input side and the output side being coupled to one another by a hydraulic fluid; a temperature sensor equipped for periodic sensing of a temperature of the hydraulic fluid; and a control unit for determining an operating status of the hydrodynamic clutch, the control unit comprising: an interface for connecting with the temperature sensor; and a processor arranged for determining a thermal output supplied to the clutch using the temperature of the hydraulic fluid, determining a lambda value using the thermal output, and determining a fill level using the lambda value.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0020] FIG. 1 a schematic depiction of a clutch system having a hydrodynamic clutch;

[0021] FIG. 2 a flow chart of a method for determining a current filling of the hydrodynamic clutch with fluid;

[0022] FIG. 3 a flow chart of a method for determining a current filling of the hydrodynamic clutch;

[0023] FIG. 4 a flow chart of a method for determining power transferred via the hydrodynamic clutch;

[0024] FIG. 5 a flow chart of a method for determining a remaining life span of the fluid in a hydrodynamic clutch;

[0025] FIG. 6 a flow chart of a method for determining a remaining life span of an antifriction bearing in a hydrodynamic clutch; and

[0026] FIG. 7 a flow chart of a method for determining a time until the next possible ramp-acceleration of a hydrodynamic clutch.

[0027] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Referring now to the drawings, and more particularly to FIG. 1, there is shown a clutch system 100 having a hydrodynamic clutch 105 and a control unit 110. Clutch 105 has an input side 115 and an output side 120 which together are rotatably mounted around a common axis of rotation 125. A hydraulic fluid 130 produces a torque coupling between input side 115 and output side 120. Input side 115 is mounted opposite to output side 120 with at least one antifriction bearing 135. Depending upon a clutch type, the connections for introduction and termination of torque loads on the antifriction bearings 135 can vary, even if their arrangement is unchanged. One or more seals 140, which can include various materials, can be provided between input side 115 and output side 120.

[0029] Clutch 105 may be available in one or several predefined embodiments. Clutch system 100 can for example be used with clutches 105 having different, predetermined diameters in a range of approximately 154 to 1150 mm. Each of these clutches 105 can be configured for transfer of a predetermined maximum power within a predetermined torque range. The power can for example be in a range of approximately 100 W to approximately 5 MW, and the torque in a range between approximately 300 and 4000 min.sup.1. Clutches 105 can also be available in different embodiments, for example with or without housing, with single or double pump wheel-turbine wheel arrangement or with different types of equalizing chambers for temporary storage of fluid 130. Each clutch 105 can therein have specific characteristics, for example a thermal reaction in answer to a predetermined load.

[0030] Certain predefined parameters or their intermediate values can be saved and/or be graphically processed. Thus, a trend of a parameter can for example be visualized at any given time. In another embodiment, one or several parameters can be compared with threshold values and when falling below or exceeding the threshold value a signal can be issued. A signal can also be issued based on logical interlinking of several conditions. The signal not only points to a certain condition, for example an imminent excessive temperature of clutch 105, but also to a suggested solution, for example shutting off the drive motor that is connected with input side 115 or reducing the load through the working machine that is connected with the output side.

[0031] A predetermined volume of fluid 130 is typically filled into clutch 105, wherein fluid 130 during operation is circulated. However, the fluid 130 normally does not leave clutch 105, for example in order to flow through a heat exchanger. One also refers to a constant filling in this instance. Fluid 130 normally consists of a mineral or synthetic oil, but may be provided on a water basis, for example when using clutch 105 in an explosive environment.

[0032] Control unit 110 has a first interface 145 for connection with a temperature sensor 150 that is configured for sensing the temperature of hydraulic fluid 130 in clutch 105. Temperature sensor 150 may be designed for non-contact temperature measurement in order to provide the temperature of fluid 130 flowing around axis of rotation 125, outside of clutch 105 which rotates around axis of rotation 125 during operation. However, one or several additional sensors can be provided to sense a measured value on clutch 105. The measured value can however also be provided with another device, for example a control or measuring device. In this case, the measured value can also be acquired via interface 145 or a dedicated interface of control unit 110.

[0033] Control unit 110 is configured to identify an operating status of clutch 105, wherein the operating status includes several parameters, each of which can be identified on the basis of the temperature of hydraulic fluid 130. The control unit 110 may include a second interface 155, in order to supply the identified operating status or other information, in particular to a terminal device 160. Control unit 110 can include a memory device 165, or can be connected with same, wherein storage device 165 can be configured to store sensed measured values, determined parameters or other identified results. Moreover, constants, characteristic curves or other information which are specifically for determination of a parameter for a predefined clutch 105, for example a thermal behavior of clutch 105 in response to a predefined load, can be stored in memory device 165.

[0034] Terminal device 160 can be arranged for interaction with a person, for example in that one or several parameters of the operating status can be indicated. Terminal device 160 can also be used for control of control unit 110, perhaps to call up predetermined stored parameters or in order to influence the identification of the parameters. In another embodiment, terminal device 160 can also include a control unit that is arranged for control of clutch 105, control of a component driving clutch 105 or control of a component being driven by clutch 105. Depending on the operating status, terminal device 160 can in particular be arranged to limit or stop a transfer of torque via clutch 105. In another embodiment, the control function can also be performed by control unit 110.

[0035] Below, exemplary identifications of parameters are discussed, several of which can be included in the operating status of clutch 105. It must be considered that the individual methods for determining of parameters are conducted simultaneously or more specifically, concurrently. An initialization step that may be necessary for several of the methods can be integrated cross-procedurally into one step. In the initialization step several values or data can be provided, for example by manual input.

[0036] The methods respectively include continuous loop to cyclically perform their determinations. The continuous loops may be integrated with one another, wherein the frequency of the steps of the individual methods within the loop need not necessarily be the same. One loop may cycle through every approx. 5 s to 10 s. The step of sensing the temperature of clutch 105 is common to all methods. Certain parameters of the described methods can build on one another, for example in that an aging of fluid 130 is determined on the basis of a power that is transferred via clutch 105. The sequence of the steps in the continuous loop is thus to be selected accordingly. Under certain circumstances, for example if one component of clutch 105 undergoes maintenance or is replaced, parameters of one or of several methods are reset to initial values.

[0037] FIG. 2 shows a flow chart of a method 200 for determining a current filling of hydrodynamic clutch 105 with fluid 130. In an initialization stop 205, a type of clutch 105 may be determined. Subsequently a loop of steps 210 to 220 is cycled through periodically, for example approximately every 5 or 10 seconds.

[0038] In step 205 the temperature of fluid 130 of clutch 105 is determined. A determination of power P that is transferred via clutch 105 occurs in a step 210.

P=A.Math./t.Math.effective thermal capacity of the clutch

[0039] The effective thermal capacity of the clutch is again a function of the rate of heating. The effective thermal capacity of the clutch on the one hand includes a component that stems from the thermal capacity of the clutch, and on the other a component that stems from the thermal capacity of the fluid in the clutch.

[0040] The following applies: /t: maximum value of the measured/calculated rate of heating during the first 5 s after motor start (conditions for motor start: /t>0.5K/s and the speed of the clutch n2 is or respectively was zero in time period 10 s prior). In consideration of the respective fill level in the clutch, the thermal capacity of the clutch and the thermal capacity of the fluid flow into the effective thermal capacity of the clutch.

[0041] In a subsequent step 215, the lambda value .sub.A is determined on the basis of the transferred power:

[00001]${}_A=\frac{P}{{}_{\mathrm{Fluid}}.Math.D_P^5.Math.{}_1^2.Math.z}$ [0042] where: [0043] P: supplied thermal output [0044] P.sub.Fluid: density operating medium (Oil: 840 kg/m3; Water: 980 kg/m3) [0045] D.sub.P: profile diameter [m] [0046] 1: n.sub.N*: wherein only n.sub.N over n2 and a table or data bank are determined [0047] z: number of cycles. If one pump wheel and one turbine wheel are provided, then z=1;
if respectively two are provided which are coupled in pairs, then z=2.

[0048] The fill level is a function of .sub.A, clutch type, clutch diameter and hydrodynamic profile.

[0049] If clutch 105 is in stationary operation, another method can also be selected for determining the current fill of a hydrodynamic clutch 105 with fluid 130.

[0050] FIG. 3 shows a flow diagram of a corresponding method 300. Rated speed n.sub.N is determined in an initialization step 305. This can be performed on the basis of the steady speed n.sub.2 by use table, so that for example 1458 min.sup.1 to 1490 min.sup.1 are mapped. Subsequently a loop of steps 310 to 315 may be cycled through periodically, for example approximately every 5 or 10 seconds. In step 310, temperature .sub.VTK of fluid 130, temperature .sub.amb. and speed n.sub.2 of clutch 105 are determined.

[0051] In step 315 a fill loss of clutch 105 is determined. The determination is made on the basis that the power that is transferred via clutch 105 is P.sup.C and that moreover Pm.Math.s applies. Thereby, c is a number m is the increase of the rated slippage line.

[0052] Thus, the following applies:

[00002]$\frac{{}^c}{s}=\frac{{}^c}{\left(1-\frac{n_2}{n_N}\right)}=k.Math.m=\mathrm{const}.$

[0053] If clutch 105 leaks, then the quotient described above is no longer on this line. This criterion can be utilized for determining a leakage. Factor k.Math.m may be defined when the temperature .sub.VTK of fluid 130 is already at steady state. This is the case for example if condition

[00003]$\frac{}{.Math..Math.t}<0,01.Math.\frac{K}{s}$

is fulfilled for at least approximately 10 minutes. This will eliminate that temperatures that are too high from ramping up of the clutch 105 are being captured. Cyclical load fluctuations with constant temperature .sub.VTK of clutch 105 can however be captured. It is assumed that, during a load change the load speed changes sinusoidally.

[0054] If the above condition is met, a value that contains for example approximately 100 values may be loaded into a FIFO memory

[0055] For n.sub.2, when saving, the mean value of the last 10 minutes must be used. A mean value for k*m can then be created from this FIFO-memory.

[0056] In stationary operation, that is in steady state, the filling loss can then be detected as follows:

[00004]$\frac{{}^c}{\left(1-\frac{.Math..Math.n_2}{n_N}\right)}<0,75.Math.\left(.Math..Math.k.Math.m\right)$

[0057] The following applies: [0058] m: increase of rated slippage line [0059] n.sub.2: mean value of output speed over approx. last 10 minutes [0060] (k.Math.m): average of last approx. 100 values of (k.Math.m)

[0061] The factor of 0.75 results from that the difference of the increase in the constant filling normally is no greater than 25%. A modified factor can be used in other embodiments, to present a given clutch 105 in an improved manner.

[0062] If a reduced fill level was determined, a signal can be issued accordingly. The signal may be issued only when the fill level falls below a predefined threshold value.

[0063] In step 210 in the above described method 200, the thermal output introduced into clutch 105 is determined on the basis of the mechanical power that is transferred via clutch 105. The mechanical power can be measured or can be determined by a process.

[0064] FIG. 4 shows a flow diagram of a method 400 for determining a power that is transferred via a hydrodynamic clutch 105. Method 400 can in particular be performed integrated with method 200 shown in FIG. 2. In an initialization step 405, at least one of the following must be provided: maximum operating temperature .sub.max of clutch 105, one dimension of clutch 105, e.g. its diameter or one known clutch type, one operating medium and one statement of whether seal 140 consisting of the material Viton is used.

[0065] Normally, oil and water are considered for operating media. The operating medium is analyzed in a step 410. In the case of water, .sub.B,max is set to a predefined C.-value in a step 415, and method 400 continues with a step 445. Otherwise it is determined in a step 420 as to whether Viton is used as the material for seals 140. If this is not the case, a seal material such as NBR is assumed and .sub.B,max is set to a predefined C.-value in a step 425. The method subsequently continues with step 445. If in contrast, Viton is used, then .sub.B,max can be determined on the basis of the clutch size. In a step 430 it is determined whether the clutch diameter falls short of a predefined clutch diameter. In that case, .sub.B,max is preferably set to a predefined C.-value in a step 435. For clutches 105 that have a larger diameter, .sub.B,max can be set to another predefined C.-value. Method 400 continues in both cases with step 445.

[0066] In step 445, temperature .sub.VTK of fluid 130 of clutch 105 and temperature .sub.amb of the surrounding area of clutch 105 are sensed. In a subsequent step 450, the relative power transferred by clutch 105 is determined as follows:

[00005]$P_{\mathrm{Load}.\mathrm{relative}}=\left(\frac{{}_{\mathrm{VTK}}-{}_{\mathrm{amb}.}}{.Math..Math.\mathrm{amb}.Math.{.}_{B.\max }}.Math.O^c\right)$

[0067] If, for example the clutch temperature is .sub.VTK=78 C., the ambient air temperature .sub.amb.=31 C. and .sub.B,max=95 C., then the relative load is:

[00006]$P_{\mathrm{Load}.\mathrm{relative}}={\left(\frac{78-31}{95-31}\right)}^c=0,{734}^c$

[0068] In an additional embodiment, the absolute power can be determined on clutch 105 instead of the relative power:

[kW]P[kW]=*.sub.Fluid*.sub.1.sup.3*D.sub.P.sup.5*z [0069] where: [0070] Dp: profile diameter [0071] .sub.1: =n.sub.N [0072] z: number of cycles. If a pump wheel and a turbine wheel are provided, them z=1, if respectively two are provided, then z=2. [0073] =m*s [0074] m: increase of rated slippage line

[0075] The increase of the rated slippage line m can only be determined inaccurately, due to varying possible heat dissipation, so that the output cannot be determined very precisely. In an alternative embodiment, a stored rated slippage line can be used that can be selected from a group of rated slippage lines on the basis of an input of an exact filling of clutch 105 with fluid 130. However, the nominal slippage line normally has a deviating progression, so that due to the approximation of a constant increase, a substantial error could be entered into the determination. Moreover, additional errors (for example the viscosity of fluid 130) could further compromise the determination.

[0076] For further improved control of clutch 105, additional parameters can be determined. It is in particular suggested, to determined parameters that point to a remaining life span of elements, such as fluid 130 or a bearing 135.

[0077] FIG. 5 shows a flow diagram of a method 500 for determining a remaining life span of fluid 130. In an initialization step 505 the type of fluid 130 is determined. Normally, an operator will input an appropriate value into a terminal device 160. Internal counters and analyzers of method 500 which are described in further detail later, may be reset in step 505. Step 505 must generally always be performed after filling of fresh fluid 130 into clutch 105.

[0078] Subsequently a loop of steps 510 to 530 is periodically cycled through, for example every 10 seconds. In step 510, temperature .sub.VTK of fluid 130 of clutch 105 is sensed. Subsequently a current load value is determined in step 515. For this purpose, a certain temperature may be looked up in a table 535 or 540 which is then multiplied with the length of the interval between two measurements. In one embodiment, the exemplary table 535 is used if fluid 130 includes synthetic oil according to initialization step 505, and exemplary table 540 is used if it includes mineral oil. If fluid 130 is water, the determination in regard to life span can be suspended.

[0079] For example, at an interval of t of 10 seconds, a determined temperature .sub.VTK of synthetic fluid 130 of 148 C. leads to a table value of 64, so that the current load value is 10 s*64=640 s.

[0080] In step 520, current load values which are determined in n loop cycles since last initialization step 505 are added up. The degree of utilization k of fluid 130 is the determined in step 525, for example:

[00007]$k=\frac{\underset{i=0}{\overset{n}{.Math.}}.Math..Math.X_i.Math..Math..Math.t}{40000.Math.h}.$

Remaining time t.sub.rem.fluid can then be determined:

t.sub.rem.Fluid=n.Math.t.Math.(1/k1)

[0081] In the case of k<1, the maximum life span of fluid 130 has not yet been reached. Otherwise, an indication in regard to the elapsed life span of fluid 130 can be issued in step 530.

[0082] FIG. 6 shows a flow diagram of a method 600 for determining a remaining life span or respectively degree of utilization of antifriction bearing 135. In an initialization step 605, at least one of the following must be determined: the size of clutch 105, on the basis of its diameter or a known clutch type, a rated speed n.sub.N, a connecting coupling type, a type of antifriction bearing 135 and an event probability. The connecting coupling type can describe how connections on input side 115 and output side 120 are configured. Clutch 105 may for example be configured such that its weight is distributed to its input side 115 and its output side 120 when axis of rotation 125 is positioned horizontally (design GPK). Other embodiments are also conceivable. The type of antifriction bearing 135 may for example indicate if it is a bearing that is sealed on one side or on both sides, which is perhaps designed to be continuously running or whether it is perhaps a bearing having increased bearing clearance.

[0083] A nominal event probability L.sub.10h is dependent on the clutch type and the clutch diameter. In stored tables, as sketched for example in FIG. 6 in 610 and 615, event probabilities are stored which can be selected depending on a clutch diameter from a characteristic curve of a first diagram 610 or a second diagram 615.

[0084] First diagram 610 relates to clutches 105 of type EPK, ENK or EEK. These clutches have classic plug connection with elastomer elements which elastically absorb shifting misalignment in elastomers. The hub of VTK is for example mounted on the transmission shaft and the installation and operation related misalignment are elastically bridged/absorbed. Depending on the elastomer characteristic curve, reset forces occur between the clutch locations that support themselves on the VTK mounts.

[0085] Second diagram 615 relates to clutches of type GPK (all metal package clutch). This clutch has VTK clutch with gimbal mount between two joints. These joints include mutually screwed together spring steel toroidal disc packages as elastically deformable elements. A GPK clutch displaces itself only angularly and axially in each of the two clutch elements 115, 130 and is very rigid in radial direction and direction of rotation. Reaction forces resulting from the displacement of GOK elements are very minimal.

[0086] Both diagrams 610, 610 are based on a clutch 105 with constant filling of fluid 130 (identification T). The curves illustrated in diagrams 610 and 615 are each allocated to certain diameters of clutches 105 and can be part of the type identification.

[0087] Subsequently a loop of steps 620 to 645 may be cycled through, periodically, for example every 5 seconds. In step 620, temperature .sub.VTK of fluid 130 is determined. In subsequent step 625 a temperature factor f.sub.Temp is determined on the basis of the temperature.

[00008]$f_{\mathrm{Temp}}=\frac{1}{j.Math.\sqrt{1.Math.\text{/}.Math.{}_{\mathrm{VTK}}}}$

[0088] A start up frequency can be considered in that in step 630 a time ratio of the start frequency is determined for example as follows:

[00009]$w=\frac{\mathrm{operating}.Math..Math.\mathrm{time}.Math..Math.\mathrm{start}}{\mathrm{operating}.Math..Math.\mathrm{tine}.Math..Math.\mathrm{total}}$

wherein the operating time start is counted if speed n.sub.2 on output side 120 is below a predetermined threshold value, for example 0.87*n.sub.N. Otherwise the operating time is counted as total. Subsequently start frequency factor f.sub.start can be determined in step 635. This can be determined on the basis of calculated values which are stated in the form of a dime-dependent curve.

[0089] The curve can be determined in that the bearing life span for a start-up time is described, bearing life spans for longer start-up times are determined, the lifespans for the formation of factors to describe the reduction are used and the factors are described in a time dependent manner by a polynomial, for example of the sixth degree.

[0090] In step 640 a slippage of clutch 105 may be considered. For this purpose a slippage factor f.sub.slippage is determined:

[00010]$f_{\mathrm{Slippage}}=\{\begin{array}{c}s<2.Math.\%.fwdarw.f_{\mathrm{Slippage}}=1.Math.\text{/}.Math.l\\ 2.Math.\%s4.Math.\%.fwdarw.f_{\mathrm{Slippage}}=\frac{1}{\mathrm{fs}\left(s\right)}\\ s>4.Math.\%.fwdarw.f_{\mathrm{Slippage}}=1.Math.\text{/}.Math.b\end{array}.Math..Math.\mathrm{with}.Math..Math.s=\left(1-\frac{n_2}{n_N}\right).Math.100$

l and b are predefined values and f.sub.s is a function in dependency on s.
In step 645 the load on antifriction bearing 135 can then be determined as follows:

f.sub.current=5s.Math.f.sub.Temp.Math.f.sub.Start.Math.f.sub.Slippage.Math.a.sub.1.Math.a.sub.23

[0091] Where:

[0092] a1: Factor for event probability

[0093] a23: Factor for viscosity dependency

[0094] The basis in the described example is a periodic determination every 5 s in other embodiments a more or less frequent determination may occur. The above referenced factors are then to be adapted accordingly. Should one of the factors described above (in regard to temperature, start frequency or slippage) not be obtained it can be made on the basis of an estimated value.

[0095] The load occurring cumulatively since the last bearing replacement is totaled through all current loads:

t.sub.Sum=.sub.0.sup.nt.sub.current.Math.

[0096] The degree of utilization k of the bearings is calculated thus:

[00011]$k=\frac{t_{\mathrm{Sum}}}{L_{10.Math.h}^{}}$

[0097] If value k reaches or exceed value 1, a notification may be issued that replace of antifriction bearing or bearings 135 is necessary. Otherwise, no remaining operating time can be given.

[0098] The remaining operating time of the bearing t.sub.rem.bearing calculates to:

t.sup.rem.bearing=t.sub.op time so far.Math.(1/k1)

[0099] In yet another embodiment, the time to the next possible acceleration of hydraulic clutch is determined.

[0100] FIG. 7 shows a flow diagram of a corresponding method 700. In an initialization step 705 one of the following may be determined: nominal speed n.sub.N, a dimension, a type, filling with fluid 130 and an operating medium of clutch 105. A diameter can be used as the dimension. An actual or a projected volume of fluid 130 can be specified as the filling.

[0101] Subsequently, steps 710 and 715 are cycled through, either in a time controlled manner, for example every approx. 5 seconds or approx. 10 seconds, or in an event controlled manner. In step 710, temperature .sub.VTK of fluid 130 and temperature .sub.amb. surrounding clutch 105 and drive speed n.sub.2 may be determined. A required cooling period during which clutch 105 should be at a standstill before it starts again can be determined in step 715. The necessary minimum cooling period on the one hand depends on the temperature of the clutch at the time of shut-down, and the effective thermal capacity of the clutch, as well as the ambient temperature. Moreover, it can be provided that the load on the clutch during a restart is considered.

.sub.start,min=.sub.VTK.sub.VTK, start [0102] Where: [0103] .sub.VTK,max,during run-up: max value of .sub.VTK for: 0<n.sub.2<((n.sub.1 2.Math.s.sup.1)/n.sub.1N)<0.001 [0104] .sub.VTK, start: VTK if n.sub.2 after min. approx. 30 s is again >0 for the first time

[0105] Moreover, differentiation can be made .sub.start,min after a load condition. The criterion can be that n2 prior to shut-off ((n.sub.1 2.Math.s.sup.1)/n.sub.1N)<0.001 and median value n.sub.2 approx. 5 s to approx. 10 s is taken from the following table prior to reaching this condition:

TABLE-US-00001 .sub.start.min 0.995*n.sub.N > 0.99*n.sub.N > n.sub.2 n.sub.2 1*n.sub.N n.sub.2 0.995*n.sub.N 0.99*n.sub.N 0.985*n.sub.N . . . . . . 0.9*n.sub.N . . . . . . . . . FIFO-memory with . . . i.e. 20 values . . .

[0106] The intervals created in the table for n2 are purely exemplary. Only the range of up to 10 percent slippage is considered, since this concerns the load evaluation prior to shutting off. A longer term operation of above 10 percent slippage is normally not possible, since this would threaten a thermal overload and based on its output side characteristics curve, the clutch could come to a short-term stand still.

[0107] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

COMPONENT IDENTIFICATION

[0108] 100 Clutch system [0109] 105 hydrodynamic clutch [0110] 110 control unit [0111] 115 input side [0112] 120 output side [0113] 125 axis of rotation [0114] 130 fluid [0115] 135 antifriction bearing [0116] 140 seal [0117] 145 first interface [0118] 150 temperature sensor [0119] 155 second interface [0120] 160 terminal device [0121] 165 reservoir [0122] 200 method for determining a current fluid filling of a hydrodynamic clutch [0123] 205 sensing of temperature [0124] 210 determining thermal output [0125] 215 determining lambda-value K [0126] 220 determining degree of filling [0127] 300 method for determining a current filling in a hydrodynamic clutch with fluid, during stationary operation [0128] 305 initialization step [0129] 310 sensing of temperature [0130] 315 determining degree of filling [0131] 400 method for determining a power transferred via a hydrodynamic clutch [0132] 405 initialization step [0133] 410 operating medium [0134] 415 [0135] 420 seal material of Viton [0136] 425 [0137] 430 [0138] 435 [0139] 440 [0140] 445 sensing of temperature [0141] 450 determining transferred power [0142] 500 method for determining a remaining life span of a fluid in a hydrodynamic clutch [0143] 505 initializing: determining type of fluid [0144] 510 sensing of temperature [0145] 515 determining current load value [0146] 520 adding up [0147] 525 determining degree of utilization [0148] 530 issuing possible notification [0149] 535 tablemineral oil [0150] 540 tablesynthetic oil [0151] 600 method for determining a remaining life span of an antifriction bearing [0152] 605 initialization [0153] 610 first diagram [0154] 615 second diagram [0155] 620 sensing of temperature [0156] 625 determining the temperature factor [0157] 630 determining time ratiostart frequency [0158] 635 determining start frequency factor [0159] 640 determining slippage factor [0160] 645 determining life span [0161] 700 method for determining a time unto the next possible run up of a hydrodynamic clutch [0162] 705 initialization step [0163] 710 sensing of temperature [0164] 714 determining wait time