DE10155459A1 - Motor vehicle has device for computing temperature of automated coupling and/or gearbox from energy input or power derived from torque and revolution rate values - Google Patents

Abstract

The device has a control unit that computes an energy input or a power using torque and revolution rate values and derives the temperature of the clutch or gearbox therefrom. The temperature of a drive motor or part thereof, e.g. the coolant temperature or the engine oil temperature, is also used to derive the temperature. Independent claims are also included for the following: a method of computing a temperature, a motor vehicle with an automated coupling and a method of controlling an automated coupling.

Description

The invention relates to a device for determining a temperature of a automated clutch and / or an automated transmission one Motor vehicle.

A device for calculating a temperature of a clutch is through DE 196 02 006 became known. In such devices, the Temperature by means of the energy introduced by the friction of the Coupling determined in the slipping state and from this a temperature of Clutch calculated. However, this device can only control the temperature determine if the device is on and continuous Can perform calculations. On the other hand, the device temporarily switched off, the thermal behavior after switching on again the device can only be detected inaccurately.

The object of the present invention is, in particular for couplings and / or transmissions of motor vehicles a reliable one  Perform temperature determination, without doing this specifically intended costly temperature sensors should be achieved.

This is the case with an above-mentioned device, which is a control unit comprises which one by means of torque values and speed values Energy input or an energy or power calculated and from it one Temperature of the clutch and / or the transmission determined, thereby achieved, that for the temperature calculation the temperature of a Drive motor or an element of the drive motor, such as the coolant temperature or the engine oil temperature.

By in a vehicle to monitor the vehicle engine provided sensors, such as the coolant temperature and / or the engine oil temperature or another direct or indirect temperature of the Motors, can improve the determination of the clutch or Transmission temperature can be reached. This can be achieved because these temperature values are available in the vehicle and temperatures of parts whose timing behaves similar to the temperature change are the timing of clutch or transmission, so that due to the detected time behavior of the temperature of the engine a change in Temperature of the clutch can be determined.  

It is advantageous if the temperature of the drive motor or one Element of the drive motor during the initialization of the Temperature determination of clutch and / or transmission is used. This is advantageous because at the beginning of the temperature determination for example after switching on the ignition of the vehicle and a switching on or initialization of the device according to the invention a sensible starting value of the temperature can be derived from the current engine temperature or one of them derived temperature for clutch or gearbox.

It is also appropriate if the temperature of a drive motor or one Element of the drive motor for determining an initial value for the tem temperature determination of clutch and / or transmission is used.

According to a further inventive idea, it is expedient if the temperature of the clutch and / or the transmission T _CG _new is determined after an initialization of the device according to:

(T _KG _new - T _KG _tief) =
(T _M _new - T _M _tief) / (T _M _hoch - T _M _tief) * (T _KG _alt - T _KG _tief)

with: T _KG _new = new temperature to be determined for the clutch or gearbox; T _KG _tief = lowest value of the clutch temperature or gearbox temperature for the calculation, e.g. B. 0 ° C; T _M _new = newly determined temperature of the motor, such as. B. coolant temperature; T _M _tief = lowest value of the engine temperature for the calculation, such as B. 0 ° C; T _M _high = maximum value of the motor temperature for the calculation, such as B. 300 ° C; T _KG _alt = temperature of clutch or gearbox last saved in the last operating phase.

According to a further inventive idea, it is also advantageous if the temperature of the clutch and / or the transmission T _CG _new is determined after an initialization of the device according to:

(T _KG _neu - T _KG _tief) = (T _M _neu - T _M _tief) / (T _M _alt - T _M _tief) * (T _KG _alt - T _KG _tief)

with: T _KG _new = new temperature to be determined for the clutch or gearbox; T _KG _tief = lowest value of the clutch temperature or gearbox temperature for the calculation, e.g. B. 0 ° C; T _M _new = newly determined temperature of the motor, such as. B. coolant temperature; T _M _tief = lowest value of the engine temperature for the calculation, such as B. 0 ° C; T _M _alt = last stored temperature of the engine temperature in the last operating phase; T _KG _alt = last saved temperature of clutch or gearbox in the last operating phase.

It is also useful if based on the engine temperature or a tempera structure of an element of the drive motor, such as the coolant temperature temperature or the engine oil temperature, the shutdown time of the vehicle it is determined that the measured after switching on the vehicle Engine temperature or the temperature of the element is compared with one before the shutdown of the vehicle stored engine temperature or tempera structure of the element and based on these two values using a table and / or the switch-off duration is determined using a mathematical calculation.

According to a further idea according to the invention, it is a motor vehicle with an automated clutch with one from a control unit Memory controllable actuation unit for automated actuation of the Coupling, advantageous if a value of the used by the control unit Coefficient of friction RW by the control unit on the physika actually present The coefficient of friction of the clutch is adjusted.

It is expedient if the control unit is used for control purposes friction coefficient as a function of the temperature of the clutch and / or the changes speed of the clutch temperature is changed.

It is also advantageous if the maximum change of the control unit used value of the coefficient of friction per unit of time is limited.  

It is also advantageous if the limitation of the temperature of the dome tion and / or the rate of change of the temperature of the clutch is selectable.

The invention is illustrated below with reference to the figures Exemplary embodiments explained. It shows:

Fig. 1 shows schematically a motor vehicle;

Fig. 1 shows a schematic representation of a motor vehicle with a drive motor 1 with a clutch 2 and a transmission 3 in the drive train. Furthermore, a differential 4 , output shafts 5 and wheels 6 driven by the output shafts are shown. On the wheels, speed sensors, not shown, can be arranged, which detect the speeds of the wheels. These wheel speed sensors are used to record or calculate the transmission input speed. If there is a sensor error or these signals are not available, the control unit can switch to emergency operation. If all regular signals are present, normal operation is present. The speed sensors can also functionally belong to other electronic units, such as an anti-lock braking system (ABS). From at least one wheel speed, at least one vehicle speed and / or one transmission speed can be determined by means of a control unit 7 . The drive unit 1 can also be configured as a hybrid drive with, for example, an electric motor, a flywheel with a freewheel and an internal combustion engine. The hitch be 2 is designed as a friction clutch, where it can also be configured, for example, as a magnetic powder clutch, multi-plate clutch or torque converter with wall lock-up clutch or as another clutch. The friction clutch can also be designed as a self-adjusting clutch that adjusts for wear.

The device for the automated actuation of a transmission 3 comprises a control unit 7 and an actuator 8 which can be controlled by the control unit 7 . Likewise, the control unit 7 can control an actuator 11 for the automated actuation of the clutch 2 . A control unit 7 and a schematically illustrated actuator 8 can be seen in FIG. 1. The control unit 7 can be designed as an integrated control unit, which carries out the control or regulation of, for example, the clutch and the transmission. Motor electronics can also be integrated in the control unit. Likewise, the control of the clutch and the transmission, or rather the actuators 7 , 11 for actuating the clutch and the transmission, can be carried out by different control units. It is also possible that the control units of the coupling, transmission and / or engine control are arranged separately and communicate with one another via data and / or signal lines. Furthermore, the control units or electronic units are in signal connection with sensors which transmit the operating parameters of the current operating point to the control unit or the control units. It is also possible that the control unit receives all the required information via data lines or a data bus, such as for example CAN bus.

The control unit 7 is equipped with a computer unit in order to be able to receive, process, store, retrieve and forward the incoming signals and system variables. Furthermore, the control unit generates control variables and / or signals for controlling actuators for actuation and for forwarding them to other electronic units.

The clutch 2 is mounted on a flywheel 2 a or connected to it. The flywheel can be designed as a one-piece flywheel or as a divided flywheel with primary mass and secondary mass, wherein a torsional vibration damping device is arranged between the individual flywheel masses, such as between the primary mass and the secondary mass. Furthermore, a starter ring gear 2 b can be arranged on the flywheel. The clutch has a clutch disc 2 c with friction linings and a pressure plate 2 d and a clutch cover 2 e and a plate spring 2 f. The self-adjusting clutch additionally has means which allow adjustment and wear adjustment, a sensor such as a force or displacement sensor or angle of rotation sensor being present, which detects a situation in which adjustment is necessary due to, for example, wear and tear detection is also carried out automatically.

The clutch is actuated by means of a release 9, for example with a release bearing 10 . The control unit 7 controls the actuator 11 , which carries out the actuation of the clutch. The release mechanism can be actuated electromotorically, electrohydraulically, such as, for example, actuated by pressure medium, such as hydraulically or by means of another actuating mechanism. The back 9 with release bearing 10 can be designed as a central release, which is arranged coaxially to the transmission input shaft and by means of loading, for example, the plate spring tongues of the clutch, the clutch engages and disengages. The release can also be designed as a mechanical release, which actuates a release bearing or a comparable element, strikes or operates.

The actuator 8 actuates the transmission 3 for switching and / or selection in particular with its at least one output or actuation element or with a plurality of output or actuation elements. The control of the shift and / or selector actuation depends on the design of the transmission.

In particular, transmissions with a central selector shaft are to be considered, at which a switching or dialing process by eel actuation or Actuation in the circumferential direction of the central control shaft, or vice versa he follows. An actuator actuates the, for example, with an actuating element axial actuation of the central control shaft and with another actuation element actuation of the shaft in the circumferential direction. The Schaltbe movement in the circumferential direction and the selection operation in the axial direction or the other way around.

Furthermore, gearboxes with two shafts are to be considered, each with one Shaft for shifting and a shaft for selecting the gear ratio are present, both shafts being actuated in the circumferential direction by one Switching operation or a selection process.

Gearboxes with shift rods should also be considered, in which the shift rods in the axial direction to be operated with a switching operation Gear ratio to switch, a selection process by selecting the actuated shift rod takes place.

The shafts or shift rods represent internal shaft elements or the shafts actuate them within the transmission when actuated. The actuator 8 actuates directly or indirectly internal gear shift elements for inserting, removing or changing gear stages or gear ratios, such as a central shift shaft, shafts or shift rods or other shift elements.

The control unit 7 is connected via the signal connection 12 to the actuator 8 , so that control signals and / or sensor signals or operating status signals can be exchanged, forwarded or queried. Furthermore, the signal connections 13 and 14 are available, via which the control unit is at least temporarily in signal connection with further sensors or electronic units. Such other electronics units can be, for example, the engine electronics, anti-lock braking system electronics or anti-slip control electronics. Further sensors can be sensors that generally characterize or detect the operating state of the vehicle, such as, for example, speed sensors of the engine or of wheels, throttle valve position sensors, accelerator pedal position sensors or other sensors. The signal connection 15 establishes a connection to a data bus, such as for example CAN bus, via which system data of the vehicle or other electronic units can be made available, since the electronic units are generally networked with one another by computer units.

An automated transmission can be switched or experience a gear change in such a way that this is initiated by the driver of the vehicle, in which he transmits a signal for shifting up or down by means of, for example, a switch, a button or another gear selection device 40 . Furthermore, a signal for the selection of the next gear to be engaged could also be given. Correspondingly, a signal can also be provided by means of an electronic shift lever in which gear the transmission is to shift.

In another transmission program, an automated actuation of the Gear can be selected so that the choice of the current gear is dependent speed is carried out by the operating parameters and, if necessary Switching process is initiated automatically. An automated transmission can but also by means of, for example, characteristic values, characteristic curves or characteristic fields and based on sensor signals at certain predetermined points Carry out gear changes independently without the driver having to change gears must initiate.

Furthermore, a neutral position N can be set, for example, in which there is no drive connection between the transmission input and the transmission output. Furthermore, a parking position P can be selected in which a parking lock is implemented. This parking position can also be selected automatically if, for example, the ignition key 51 is removed from the ignition lock and the operating state of the vehicle allows this. For example, removing the ignition key at high speeds may be mentioned, in which case a parking lock should not be inserted automatically.

The gear selection unit, such as a shift or selector lever, 40 can thus be set to one Area M, such as manual driver-side gear selection, area D, such as automatic cal gear selection for driving, an area P, such as a parking lock, and / or one Range N, such as neutral position. Furthermore, for example wise switch or a lever manual switching can be initiated. in the In the case of an automated clutch with a manually shiftable gearbox, the Shift lever manually into the respective positions assigned to the gears actuate.

The vehicle is preferably equipped with an electronic accelerator pedal 23 or load lever, the accelerator pedal 23 actuating a sensor 24 , by means of which the engine electronics 20 control or regulate, for example, the fuel supply, ignition point, injection time or the throttle valve position via the signal line 21 of the engine 1 . The electronic accelerator pedal 23 with sensor 24 is connected to the engine electronics 20 via the signal line 25 . The engine electronics 20 is connected via the signal line 22 to the control unit 7 in Signalver. Furthermore, a transmission control electronics 30 can be in signal connection with the units 7 and 20 . An electromotive throttle valve control is useful for this purpose, the position of the throttle valve being controlled by means of the engine electronics. In such systems, a direct mechanical connection to the accelerator pedal is no longer necessary or appropriate.

The vehicle also has an engine starting device 50 which, based on a driver's engine start attempt by means of, for example, actuating the ignition key 51 in the ignition lock, controls engine electronics and a starter for starting and / or starting the engine.

The control unit of the automated clutch or the automated one Gearbox has a processor that processes signals. Also points they have a memory in which data is stored and retrieved can be.

The temperature of the clutch and / or transmission can advantageously be determined, for example, by storing the cooling water or the engine oil or another temperature when the ignition of the vehicle is switched off by the driver before the control unit is automatically switched off. The temperature value is then compared when the control unit is switched on again with the value of the corresponding temperature present at the time, the switch-off time t _switch-off being obtained from the value before switch-off T _alt and the value after switch-on T _new using a temperature model according to a formula or a table can be determined:

t _shutdown = f (T _old , T _new ).

To improve the accuracy of the determination of the switch-off time, the outside temperature T _outside can also be used, in which case the following applies:

t _shutdown = f (T _old , T _new , T _outside ).

By means of the switch-off time, the temperature of the clutch and / or the Gear can be determined, for example based on the temperature Time of shutdown of the control unit stored in a memory was saved and the switch-off time and a corresponding Temperature model. Regarding the temperature model, please refer to the DE 196 02 006, whose content expressly relates to the disclosure content of the this application belongs.  

The determination of the temperature of the clutch is regarding characteristic sizes of the coupling advantageous, as these are partly are temperature dependent. For example, the coefficient of friction changes Coupling depending on the coupling temperature. So the coefficient of friction is at low temperatures rather high and decreases with increasing temperature. This means that the torque that can be transmitted by the clutch is same engagement of the clutch decreases because the transferable Torque depends on the engagement position and the coefficient of friction. takes the coefficient of friction of a slipping clutch due to the temperature increase from, the energy input becomes larger, because the clutch due to the decreasing friction coefficient slips more and the temperature rises more.

It is advantageous that the coefficient of friction RW _{st of} the clutch, which is used within the control system, is adapted to the actual physical coefficient of friction RW _ph . It is particularly advantageous if this is done in such a way that the coefficient of friction RW _St used by the control is adapted or adapted as a function of the temperature of the clutch. This can be done by setting a newly calculated coefficient of friction RW _new = RW _old + f (T _clutch ), which can be done per clock cycle of the processor or in larger time steps. Here, RW _{alt is} the coefficient of friction of the previously calculated time step and f (T _clutch ) represents a function of the temperature of the clutch, which function can be a linear function or another function.

It can also be advantageous if the maximum permissible change, maximum increment of the coefficient of friction RW _{St, is} a function of the temperature T _clutch , so that the maximum change can be made variable with the temperature per time step.

This can be done, for example, in such a way that:
MaxIncrement = K * T _clutch

This can also be done, for example, in such a way that:
MaxInkrement = A + K * dT _clutch / dt, so that the maximum permissible change in the coefficient of friction per time interval depends on the rate of change of the temperature. A and K are additive or multiplicative parameters that can be adapted to the vehicle and the clutch used. Both adaptations can also be combined.

The additive parameter A is useful in the above formula, since adjustments are also possible if the temperature is stable and thus dT _clutch / dt is zero.

Because the thermal load on a clutch is long-term Changes in the friction linings can result, it is advisable to adapt  to continue according to another thought so that they are also active remains when the temperature has returned to a normal value. This adaptation can then be based on the change in parameter A support.

According to a further inventive idea, it can be expedient if the permissible change in the coefficient of friction of RW _St is limited in accordance with the temperature of the clutch or the gradient of the temperature dT _clutch / dt of the clutch.

For example, it can be provided that the change in coefficient of friction ΔRW per adaptation step can be determined as follows:

dT _clutch / dt <0: negative limit value <ΔRW <0

or

dT _clutch / dt <0: 0 <ΔRW <positive limit

The limit values can be selected specifically for the vehicle or clutch so that the adaptation takes place with appropriately large steps.

The adaptation of the coefficient of friction when the coefficient of friction used by the controller is too high compared to the physical coefficient of friction can be recognized and carried out, for example, by setting the engine speed too high when starting off due to the coefficient of friction used in the controller being too high compared to the case that the coefficient of friction RW _{St is} substantially the same as the physical coefficient of friction. This excessively high engine speed can be detected and by changing the coefficient of friction used by the control, the clutch position is changed so that the required torque can be transmitted by the clutch.

The claims submitted with the application are drafted strikes without prejudice for obtaining further patent protection. The The applicant reserves the right to do so, so far only in the description and / or to claim disclosed features.

References used in subclaims point to further training the subject of the main claim by the features of the respective towards subclaim; they are not considered a waiver of achieving one independent, objective protection for the characteristics of the back-related To understand subclaims.  

However, the subjects of these subclaims also form independent inventions dungen, which is one of the subjects of the preceding subclaims have independent design.

The invention is also not based on the embodiment (s) of the description exercise limited. Rather, there are numerous variations within the scope of the invention Rations and modifications possible, especially such variants, elements and combinations and / or materials, for example by combination or modification of individual in connection with that in the general Be writing and embodiments and the claims described and in the features or elements contained in the drawings or procedural step ten are inventive and can be combined to create a new Ge subject or lead to new process steps or process step sequences, also insofar as they relate to manufacturing, testing and working processes.

Claims (12)

1. A device for calculating a temperature of an automated clutch and / or an automated transmission of a motor vehicle, the device comprising a control unit which calculates an energy input or a power using torque values and speed values and determines a temperature of the clutch and / or the transmission therefrom , characterized in that for the temperature calculation the temperature of a drive motor or an element of the drive motor, such as the coolant temperature or the engine oil temperature, is also used. 2. Device according to claim 1, characterized in that the temperature a drive motor or an element of the drive motor during the initialization the temperature determination of the clutch and / or transmission is pulled. 3. Device according to claim 2, characterized in that the temperature a drive motor or an element of the drive motor for determination  an initial value for determining the temperature of the clutch and / or gearbox is used. 4. The device according to claim 3, characterized in that the temperature of the clutch and / or the transmission T _CG _new after an initialization of the device is determined according to:
(T _KG _new - T _KG _tief) =
(T _M _new - T _M _tief) / (T _M _hoch - T _M _tief) * (T _KG _alt - T _KG _tief)
with: T _KG _new = new temperature to be determined for the clutch or gearbox; T _KG _tief = lowest value of the clutch temperature or gearbox temperature for the calculation, e.g. B. 0 ° C; T _M _new = newly determined temperature of the motor, such as. B. coolant temperature; T _M _tief = low engine temperature for the calculation, such as B. 0 ° C; T _M _high = maximum value of the engine temperature for the calculation, such as B. 300 ° C; T _KG _alt = temperature of clutch or gearbox last saved in the last operating phase. 5. The device according to claim 3, characterized in that the temperature of the clutch and / or the transmission T _CG _new after an initialization of the device is determined according to:
(T _KG _neu - T _KG _tief) = (T _M _neu - T _M _tief) / (T _M _alt - T _M _tief) * (T _KG _alt - T _KG _tief)
with: T _KG _new = new temperature to be determined for the clutch or gearbox; T _KG _tief = lowest value of the clutch temperature or gearbox temperature for the calculation, e.g. B. 0 ° C; T _M _new = newly determined temperature of the motor, such as. B. coolant temperature; T _M _tief = low engine temperature for the calculation, such as B. 0 ° C; T _M _alt = last stored temperature of the engine temperature in the last operating phase; T _KG _alt = last saved temperature of clutch or gear in the last operating phase. 6. The device in particular according to claim 1, characterized in that based on the engine temperature or a temperature of an element of the type drive engine, such as the coolant temperature or the engine oil temperature, the switch-off time of the vehicle is determined in that the engine temperature measured after the vehicle is switched on again ture or the temperature of the element is compared with one before the Ab switch the vehicle's stored engine temperature or temperature of the element and based on these two values using a table and / or the switch-off duration is determined using a mathematical calculation.   7. Method for calculating a temperature using a device according to one of the preceding claims. 8. Motor vehicle with an automated clutch with one of a tax Unit with memory-controllable actuation unit for automated actuation the clutch, characterized in that one of the control unit used value of the coefficient of friction RW by the control unit to the tat actual physical coefficient of friction of the clutch is adjusted. 9. Motor vehicle according to claim 8, characterized in that the of the Control unit used to control the coefficient of friction as a function of temperature the clutch and / or the rate of change of the temperature of the Clutch is changed. 10. Motor vehicle according to claim 8 or 9, characterized in that the maximum change in the value of the control unit used Friction coefficient per unit of time is limited. 11. Motor vehicle according to claim 10, characterized in that the limits tion of the temperature of the clutch and / or of the change speed of the clutch temperature is selectable.   12. Method for controlling an automated clutch according to the claims Chen 8 to 11