JP2011231787A - Protection control device of lock-up clutch in torque converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a friction material of a lock-up clutch (LC) to be used efficiently for a long life.SOLUTION: A surface temperature Tof LC for which equivalence conversion to a predetermined reference temperature (180°C, for example) is carried out is obtained as a thermal load L. This thermal load is accumulated to obtain a thermal load accumulation value ΣLof LC. The thermal load accumulation value is divided by cumulative travelling distance ΣH of a vehicle to obtain a load inclination S. The load inclination is compared with a reference load inclination RS and when the load inclination exceeds the reference load inclination, clutch protection is instructed. When this clutch protection is instructed, a clutch operation is limited so as not to cause the surface temperature of LC to rise. (When LC slip control should be performed, LC is turned OFF without performing this control, for instance.) As the reference load inclination RS, a quotient obtained by dividing the whole life warranty load time at 180°C equivalent conversion time of LC by whole life warranty distance is used. Thereby, LC can be used up efficiently over the life warranty distance.

Description

  The present invention relates to a lockup clutch protection control device in a torque converter used in an automatic transmission of a vehicle such as an automobile, and more particularly to protection against deterioration of a clutch friction material due to heat generation.

  A torque converter for amplifying torque is used in an automatic transmission mounted on a vehicle. In many cases, the torque converter is provided with a lock-up clutch that directly connects the impeller and the turbine. By providing the lock-up clutch, power transmission efficiency is increased and fuel efficiency is improved. However, in order to further improve the fuel efficiency, it is desirable to expand the engagement region of the lock-up clutch. On the other hand, since the engine torque fluctuation is directly transmitted to the drive system by engaging the lock-up clutch, it causes an increase in noise and vibration.

  Therefore, a technique is used that suppresses transmission of engine torque fluctuations to the drive system by slightly sliding the lock-up clutch. However, when the lock-up clutch is continuously slid, the surface of the friction material (facing material) becomes high temperature, and the friction material becomes mirrored, peeled off, carbonized, etc., and the frictional force is reduced. As a result, there is a possibility that a sufficient lockup clutch capacity that can counter the engine torque cannot be obtained. Further, when the surface of the friction material becomes high temperature, in addition to the heat generation of the friction material, the slip amount of the torque converter increases, so that heat generation due to work loss increases. If it does so, the hydraulic fluid in a torque converter will become high temperature, and will also lead to the deterioration of a resin component and a rubber component. In addition, when the temperature rise in the torque converter becomes significant, in the worst case, the hydraulic oil path in the torque converter may be damaged. If such a situation occurs, the torque transmission function will be significantly reduced. .

  In order to avoid such a phenomenon, Patent Document 1 discloses a technique for estimating a facing temperature of a lock-up clutch and reducing the temperature in the torque converter when the facing temperature is estimated to be a predetermined high temperature. . Specifically, when the facing temperature of the lock-up clutch becomes equal to or higher than a predetermined first allowable temperature, either the lock-up clutch is completely engaged (slip rate is zero) or the lock-up clutch is completely released. By selecting, slip control of the lockup clutch is interrupted, and the facing temperature and the internal temperature of the torque converter are lowered. Here, the first permissible temperature is a limit temperature at which the durability of the friction material is affected when the friction material of the lockup clutch reaches a higher temperature.

  Further, in Patent Document 1, when the facing temperature of the lock-up clutch is equal to or higher than a predetermined second allowable temperature, the usage time in the temperature state is cumulatively calculated, and the cumulative calculated time is set to a predetermined usage limit time. If exceeded, it is shown that the lockup operation restriction control is performed so that the friction material is not used any more. Here, the second allowable temperature is a temperature at which slight damage can be caused to the friction material due to a failure of the lockup control device or the like. Further, it is shown that a warning lamp that prompts replacement of the friction material is turned on simultaneously with the lockup operation restriction control.

Japanese Patent No. 3476718

  In the conventional control described above, no special protective measures are taken until the cumulative use time at or above the second allowable temperature that can cause minor damage to the friction material reaches a predetermined use limit time. When used, the friction material must be replaced in a shorter period than the normal life, and the friction material could not be used efficiently with a long life.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a protection control device for a lock-up clutch that can efficiently use the friction material of the lock-up clutch with a long life. is there.

  A lockup clutch protection control device in a torque converter according to the present invention includes a temperature calculation means (31) for calculating a surface temperature of a clutch friction material in a lockup clutch of a vehicle torque converter, and the clutch based on the calculated surface temperature. Load calculating means (32) for calculating a thermal load applied to the friction material; accumulating means (33) for accumulating the calculated thermal load to obtain a thermal load accumulated value of the clutch friction material; and the thermal load. Inclination calculating means (34) for obtaining a load inclination by dividing the cumulative value by the cumulative travel distance of the vehicle, and comparing the load inclination with a predetermined reference load inclination, and a clutch when the load inclination exceeds the reference load inclination A protection instructing means (35) for instructing protection and a clutch so as not to raise the surface temperature of the clutch friction material when the clutch protection is instructed. It characterized in that it comprises a clutch operation control means for limiting the switch actuation (36). In addition, the code | symbol in parenthesis shows the code | symbol of the corresponding component of embodiment mentioned later as an example of this invention.

  In the present invention, the load gradient obtained by dividing the cumulative value of the thermal load applied to the clutch friction material by the cumulative travel distance of the vehicle is the cumulative of the clutch friction material of the vehicle with respect to the cumulative travel distance. Represents the "degree" of the thermal load. The predetermined reference load inclination is a reference for evaluating this “degree”, that is, a threshold value. That is, the “degree” of the cumulative thermal load amount of the clutch friction material with respect to the cumulative travel distance at the current travel time = the load gradient exceeds the predetermined reference load gradient, compared to a reference value, that is, a threshold value, This means that the “degree” of the cumulative thermal load of the friction material is large. According to the present invention, when the load inclination exceeds the reference load inclination, the clutch protection is instructed, and when the clutch protection is instructed, the clutch operation is performed so as not to raise the surface temperature of the clutch friction material. Is controlled so that the thermal load applied to the clutch friction material does not increase. Limiting the clutch operation so that the surface temperature of the clutch friction material does not increase means, for example, that slip control that causes heat generation of the lock-up clutch is not performed, and the clutch is completely turned off in situations where slip control is required. The clutch operation control is performed so as to be engaged (OFF) or completely engaged. Due to such limitation of the clutch operation, heat generation of the lockup clutch is suppressed, and the trajectory is corrected in a direction in which the load inclination is lower than the reference load inclination. That is, according to the present invention, when the load slope exceeds the reference load slope, the clutch operation is limited as described above, whereby the trajectory is continuously corrected in a direction in which the load slope is lower than the reference load slope. Therefore, as a whole, the load gradient is always controlled so as not to exceed the reference load gradient (even if the load gradient is exceeded, it is promptly corrected).

  Thus, according to the present invention, the “degree” of the cumulative thermal load of the clutch friction material = the load gradient is controlled throughout the entire travel process so that it does not exceed the predetermined reference load gradient. The change curve of the cumulative thermal load with respect to the travel distance always shifts to the lower side of the curve defined by the predetermined reference load inclination. This means that fatal damage to the clutch friction material caused by heat generation can be avoided, and the lifetime can be used up appropriately. That is, for example, as the predetermined reference load inclination, a predetermined limit value (a limit value before reaching a fatal damage) of the cumulative thermal load value of the clutch friction material is used as the ideal friction friction material. If it consists of the value divided by the lifetime mileage set as the mileage, it will always cause fatal damage to the clutch friction material due to heat generation by controlling so as not to exceed this reference load inclination. In other words, the clutch friction material can be fully used for the set lifetime travel distance. Thus, according to the present invention, it is possible to control the friction material of the lockup clutch so that it can be used efficiently and with a long life.

  In the above control, even if the thermal load applied to the clutch friction material increases in a short period, the clutch protection may not be instructed if the accumulated thermal load value is not so large. However, the concept of clutch protection control according to the present invention can also be applied to cope with short-term clutch heat generation.

  In other words, the lockup clutch protection control device in the torque converter according to the present invention accumulates the calculated thermal load from the start of the engine in a predetermined low temperature environment to obtain the second frictional material of the clutch. A second accumulating means (37) for obtaining a thermal load accumulated value; a second accumulating value obtained by dividing the second thermal load accumulated value by the travel distance of the vehicle from the accumulation start time; The slope calculating means (38) compares the second load slope with a predetermined second reference load slope and indicates clutch protection when the second load slope exceeds the second reference load slope. A second protection instructing means (39), and the clutch operation control means (36) is configured to provide the clutch friction material even when the second protection instructing means (39) instructs the clutch protection. Above the surface temperature of And limits the clutch actuation so as not to. This makes it possible to perform clutch protection control that copes with short-term clutch heat generation.

It is a figure which shows schematic structure of the drive system mounted in the vehicle.

It is a functional block diagram of the protection control apparatus of the lockup clutch in the torque converter which concerns on one Embodiment of this invention. The graph which shows the concept of the clutch protection control according to this invention. The flowchart which shows the specific procedure in the case of implement | achieving the clutch protection control according to this invention with a computer program. The flowchart connected to FIG. 4A. The flowchart connected to FIG. 4B.

[Example of overall configuration]
FIG. 1 is a schematic diagram of a vehicle drive system to which a lockup clutch protection control device in a torque converter according to an embodiment of the present invention is applied. As shown in FIG. 1, the vehicle according to the present embodiment includes an engine 1, an automatic transmission 2 that is connected to the engine 1 via a fluid torque converter 3, and an FI-ECU 4 that electronically controls the engine 1. An AT-ECU 5 that electronically controls the automatic transmission 2 including the torque converter 3, and a rotational drive and lock-up control of the torque converter 3 and a plurality of friction engagement elements of the automatic transmission 2 according to the control of the AT-ECU 5. And a hydraulic control device 6 that hydraulically controls the engagement (engagement) and release of the.

  The rotational output of the engine 1 is output to a crankshaft (output shaft of the engine 1) 21 and transmitted to the main shaft 22 of the automatic transmission 2 via the torque converter 3. The torque converter 3 is provided with a lockup clutch 30. The lockup clutch 30 is set to either the lockup ON or OFF state according to the lockup control by the AT-ECU 5. Note that the lock-up ON control includes “tight” control in which the lock-up clutch 30 is completely engaged and “slip” control in which the lock-up clutch 30 is slid and semi-engaged. The lock-up OFF control is a control that completely releases (not fastens) the lock-up clutch 30.

  In the vicinity of the crankshaft 21, a crankshaft rotation speed sensor 201 for detecting the rotation speed Ne of the crankshaft 21 (engine 1) is provided. In the vicinity of the main shaft 22, a main shaft rotation number sensor 202 that detects the rotation number (input shaft rotation number of the automatic transmission 2) Ni of the main shaft 22 is provided. In the vicinity of the countershaft 23, a countershaft rotational speed sensor 203 for detecting the rotational speed of the countershaft 23 (the output shaft rotational speed of the automatic transmission 2) No is provided. The rotational speed data Ne, Ni, No detected by the sensors 201 to 203 and the vehicle speed data Nv detected by the vehicle speed sensor 204 are given to the AT-ECU 5.

  In the vicinity of the engine 1, a coolant temperature sensor 205 that detects a temperature Tw of engine coolant for cooling the engine 1 and a throttle opening sensor 206 that detects a throttle opening TH (not shown) of the engine 1 are provided. It is done. The engine coolant temperature data detected by the coolant temperature sensor 205 and the throttle opening data detected by the throttle opening sensor 206 are output to the FI-ECU 4. An accelerator pedal opening sensor 207 that detects the opening of the accelerator pedal 8 is provided in the vicinity of the accelerator pedal 8. The data of the accelerator pedal opening AP detected by the accelerator pedal opening sensor 207 is given to the FI-ECU 4 and the AT-ECU 5. An oil temperature sensor 208 that detects the temperature TATF of the hydraulic oil (and lubricating oil) of the hydraulic control device 6 is provided in the vicinity of an oil tank (not shown) in the hydraulic control device 6. The hydraulic oil temperature TATF data detected by the oil temperature sensor 208 is output to the AT-ECU 5.

[Description of lock-up clutch protection control]
Next, an outline of the lock-up clutch protection control related to the present invention executed by the AT-ECU 5 will be described with reference to the functional block diagram of FIG. Note that the heat generation of the lock-up clutch 30 becomes a problem at the time of lock-up ON control (especially during slip control). Therefore, the protection control according to the functional block diagram of FIG. Time).

The temperature calculation means 31 calculates (estimates) the surface temperature T _LC of the clutch friction material in the lockup clutch 30 of the torque converter 3 of the vehicle. As a method for calculating (estimating) the surface temperature T _LC of the clutch friction material, for example, the method described in Patent Document 1 (Japanese Patent No. 3476718) can be used, and any other appropriate publicly known technique. Therefore, the detailed description thereof is omitted.

The load calculating means 32 calculates a thermal load L _LC applied to the friction material of the lockup clutch 30 based on the calculated surface temperature T _LC . For example, according to the following formula 1, a current surface temperature T _LC (for example, the unit is ° C.) equivalent to a predetermined reference temperature (for example, 180 ° C.) may be obtained as the thermal load L _LC .
_{L LC = exp {(T LC} -180 ℃) / equivalent conversion factor} × computation unit time. . . (Formula 1)
In the above formula, “equivalent conversion coefficient” is a coefficient determined as appropriate in design, and the calculation unit time indicates a unit time (for example, unit is second) for performing the calculation of (Formula 1). That is, in the exponential portion _{exp {(T LC -180 ℃)} / equivalent conversion factor}, 180 ° C. equivalent conversion value per second (equivalent in terms of time) is determined, the calculation unit takes time it thereto, calculated A 180 ° C. equivalent conversion value (equivalent conversion time) of the surface temperature T _LC per unit time is obtained.

For example, if T _LC = 180 ° C., the value of the exponential function part of Equation 1 is 1, and L _LC = calculation unit time. If T _LC <180 ° C., the value of the exponential function part of Equation 1 is smaller than 1, and L _LC <calculation unit time. If T _LC > 180 ° C., the value of the exponential function part of Equation 1 above is greater than 1 and L _LC > calculation unit time. Note that the thermal load L _LC may be calculated by other methods, not limited to the above equation 1.

The accumulating unit 33 obtains the thermal load accumulated value .SIGMA.L _LC of the clutch friction material by accumulating thermal load L _LC calculated above. This thermal load cumulative value ΣL _LC is the cumulative value of the 180 ° C. equivalent conversion time. That is, the cumulative load state of the clutch friction material used under various temperature environments is equivalently converted into the cumulative use time under the 180 ° C. environment.

The inclination calculation means 34 obtains a load inclination S _LC by dividing the thermal load accumulated value ΣL _LC by the cumulative travel distance ΣH of the vehicle (S _LC = ΣL _LC / ΣH). Incidentally, the cumulative traveling distance ΣH thermal load accumulated value .SIGMA.L _LC and the vehicle is assumed to accumulate starting from the same point, for example, an accumulated value from the start of use of the clutch friction material.

The protection instruction unit 35, the load slope S _LC is compared with a predetermined reference load tilt RS, indicating the clutch protection when the load slope S _LC exceeds the reference load tilt RS.

  The clutch operation control means 36 limits the clutch operation so as not to raise the surface temperature of the clutch friction material when the clutch protection is instructed. Since the factor that increases the surface temperature of the clutch friction material is clutch slipping, the clutch operation restriction performed here is a control that turns off the clutch without performing the slip control even if the clutch slip control is instructed. Do. Thereby, the surface temperature of a clutch friction material can be reduced.

The load inclination S _LC represents the “degree” of the thermal load accumulated value ΣL _LC of the clutch friction material of the vehicle with respect to the accumulated travel distance ΣH. The predetermined reference load gradient RS is a reference, that is, a threshold value for evaluating this “degree”. Typically, based on the durability performance and durability test of the clutch friction material guaranteed by the manufacturer of the clutch friction material, the lifetime guaranteed load time at 180 ° C equivalent conversion time of the clutch friction material is obtained, and this 180 ° C equivalent A quotient obtained by dividing the lifetime guaranteed load time in the conversion time by the lifetime guaranteed distance of the clutch friction material is defined as a reference load gradient RS. That is, if it is used so as not to exceed this reference load inclination RS, the clutch friction material can be used up fully for the set lifetime guaranteed distance. As an example, the lifetime guarantee load time at 180 ° C. equivalent conversion time is 20 hours, and the lifetime guarantee distance is 240,000 km. As will be apparent, the lifetime guarantee load time should be appropriately determined according to the performance of the clutch friction material, but the lifetime guarantee distance can be arbitrarily set. By performing the clutch protection control according to the present invention, the clutch friction material can be used up over the set lifetime guaranteed distance without being thermally damaged.

FIG. 3 is a graph showing the concept of clutch protection control according to the present invention, in which the horizontal axis is the cumulative travel distance ΣH of the vehicle, and the vertical axis is the cumulative thermal load value ΣL _{LC of the} clutch friction material, that is, the cumulative equivalent 180 ° C. conversion time. Value. A curve 40 shows an example of the locus of the load slope _SLC accompanying the accumulation of the vehicle travel distance, and a straight line 41 shows an example of the reference load slope RS. According to the example of FIG. 3, when the load gradient _SLC indicated by the curve 40 exceeds the reference load gradient RS indicated by the straight line 41 at the point P1, it is instructed to perform clutch protection. When the clutch protection is instructed, the clutch operation is limited so as not to raise the surface temperature of the clutch friction material, so that the thermal load applied to the clutch friction material is not increased, and the load shown by the curve 40 is The slope _SLC is promptly controlled so as to be lower than the reference load slope RS indicated by the straight line 41 (protection control operation state). At a point P2, when a predetermined protection release condition is satisfied, the clutch protection control is released and the normal lockup clutch control is resumed. Thus, according to the present invention, when the load gradient S _LC exceeds the reference load gradient RS, the clutch operation is restricted as described above, so that the load gradient S _LC is less than the reference load gradient RS. The trajectory is constantly corrected, and as a whole, the load gradient _SLC is always controlled so as not to exceed the reference load gradient RS (even if it exceeds, it is corrected quickly).

Thus, according to the present invention, the “degree” of the cumulative thermal load of the clutch friction material = the load slope S _LC is controlled throughout the entire travel process so that it does not exceed the predetermined reference load slope RS, resulting in In addition, the cumulative thermal load change curve (curve 40) with respect to the travel distance always shifts below the curve (straight line 41) defined by the predetermined reference load slope RS. This means that fatal damage to the clutch friction material caused by heat generation can be avoided, and the set lifetime can be fully used up properly. Thus, according to the present invention, it is possible to control the clutch friction material of the lockup clutch 30 so that it can be used efficiently with a long life.

In the above control, even if the thermal load applied to the clutch friction material suddenly increases in the short-term period and there is a possibility of adversely affecting the friction material, the accumulated thermal load value ΣL _LC is not so large. The clutch protection may not be instructed. The short-term (second) accumulating means 37, the short-term (second) inclination calculating means 38, and the short-term (second) protection instructing means 39 in FIG. It is provided to perform protection control.

The short-term (second) accumulating means 37 accumulates the calculated thermal load L _LC from the start of the engine in a predetermined low-temperature environment, and the short-term (second) thermal of the clutch friction material. The load accumulated value sΣL _LC is obtained. The reason for limiting the engine only to the start of the engine in a predetermined low temperature environment is that if the engine is temporarily stopped and restarted, the short-term (second) cumulative thermal load value sΣL _LC is accumulated. This is to prevent start, that is, reset.

The short-term (second) slope calculating means 38 divides the short-term (second) thermal load accumulated value sΣL _LC by the short-term travel distance sΣH from the accumulation start time (engine start). The (second) load slope sS _LC is determined.

The short-term (second) protection indicating means 39 compares the short-term (second) load slope sS _LC with a predetermined short-term (second) reference load slope sRS, and the short-term (second) load Clutch protection is indicated when the slope sS _LC exceeds the reference load slope sRS. The clutch operation control means 36 performs control to limit the clutch operation so as not to raise the surface temperature of the clutch friction material even when the clutch protection is instructed by the short-term (second) protection instruction means 39. . This makes it possible to perform clutch protection control that copes with short-term clutch heat generation. Note that the short-term (second) reference load slope sRS may be the same as the normal reference load slope RS.

[Example of processing flow]
4A to 4C are flowcharts showing a lock-up clutch protection control program executed by the microcomputer in the AT-ECU 5. This flow is repeated every predetermined calculation unit time while the vehicle is running. This lockup clutch protection control program corresponds to the functions of the load calculation means 32 to the protection instruction means 35 in FIG. The calculation process of the surface temperature _TLC of the clutch friction material corresponding to the function of the temperature calculation means 31 in FIG. 2 is performed prior to the sequence of the lockup clutch protection control program within the calculation unit time. The detailed flow is well known and will be omitted. Therefore, when the sequence of the lock-up clutch protection control program of FIG 4A~4C is started, the surface temperature T _LC of clutch friction material in the computation unit time is assumed to have already been calculated. The function of the clutch operation control means 36 in FIG. 2 is executed by the hydraulic control device 6 in accordance with an instruction from the AT-ECU 5.

In step S1, it is checked whether the lock-up clutch (hereinafter abbreviated as LC) is currently ON-controlled (that is, whether tight control or slip control is currently being performed). If YES, in step S2, the thermal load L _LC is calculated according to the above equation 1 (corresponding to the load calculating means 32). In the next step S3, the calculated thermal load L _LC is accumulated to obtain a thermal load accumulated value ΣL _LC of the clutch friction material (corresponding to the accumulation means 33).

After step S3 or when step S1 is NO, the cumulative travel distance ΣH is calculated in step S4. In the next step S5, (corresponding to the tilt calculation means 34) for the thermal load accumulated value .SIGMA.L _LC by dividing the cumulative traveling distance .SIGMA.H of the vehicle determining the load slope _{S LC (S LC = ΣL LC} / ΣH).

In the next step S6, it is determined whether or not the engine is started in a predetermined low temperature environment. For example, it is determined whether or not the engine has been started when the hydraulic oil temperature TATF is equal to or lower than a predetermined value. If YES, in step S7, the thermal load cumulative value ΣL _LC and the cumulative travel distance ΣH calculated in steps S3 and S4 are latched as the initial values s ₀ ΣL _LC and s ₀ ΣH, respectively.

After step S7, or when step S6 is NO, in step S9, the initial values latched in step S7 from the thermal load cumulative value ΣL _LC and cumulative travel distance ΣH calculated in steps S3 and S4, respectively. By subtracting the values s ₀ ΣL _LC and s ₀ ΣH, the short-term (second) thermal load accumulated value sΣL _LC = ΣL _LC −s ₀ ΣL _LC and the short-term travel distance sΣH = ΣH−s ₀ ΣH are calculated. Then, the former is divided by the latter to obtain a short-term (second) load slope sS _LC (corresponding to the short-term accumulating means 38 and the short-term slope calculating means 38).

In FIG. 4B, in steps S9 to S12, when the surface temperature TLC of the _LC becomes a high temperature equal to or higher than the predetermined set temperature SE1, known control is performed to limit the operation of the LC and achieve LC protection. In step S9, it is checked whether T _LC > SE1. If NO, a predetermined value is preset in the timer TM1 in step S10. Note that the timer TM1 and the timers TM2 to TM7 described below are counted down one by one for each predetermined calculation unit time for executing this sequence. If step S9 is YES, it is checked in step S11 whether the value of the timer TM1 has become zero. If the value of the timer TM1 is not 0, the process goes to step S13. If the value of the timer TM1 becomes 0, the LC temperature protection flag (F_LC temperature protection) is set to 1 in step S12. With this configuration, as soon as the _LC surface temperature TLC becomes higher than the predetermined set temperature SE1, the F_LC temperature protection is not set to 1, and the downcount for the predetermined value preset in the timer TM1 is performed. F_LC temperature protection) is set to 1 on condition that the state of T _LC > SE1 has been maintained until a certain time until completion.

In steps S13 to S16, when the heat generation amount h _{LC of the LC} becomes a high temperature equal to or higher than the predetermined set value SE2, a known control is performed to limit the operation of the LC and achieve LC protection. The calorific value h _LC of _LC is calculated by a known method (for example, the method described in Patent Document 1) by an LC calorific value calculation routine (not shown). In step S13, whether h _LC > SE2 is checked. If NO, a predetermined value is preset in the timer TM2 in step S14. If step S13 is YES, it is checked in step S15 whether the value of the timer TM2 has become zero. If the value of the timer TM2 is not 0, the process goes to step S17. If the value of the timer TM2 becomes 0, the LC heat generation protection flag (F_LC heat generation protection) is set to 1 in step S16. With this configuration, as soon as the calorific value h _{LC of the LC} becomes high on the predetermined set value SE2, the F_LC exothermic protection is not set to 1, and the down count for the predetermined value preset in the timer TM2 is performed. F_LC heat generation protection) is set to 1 on the condition that the state of h _LC > SE2 has continued until a certain time until completion.

In step S17, it is checked whether the cumulative travel distance ΣH is less than a predetermined protection control exclusion distance. Tend The predetermined protective control exclusion distance, when the cumulative travel distance ΣH small value, the value of the load slope S _LC which is obtained by dividing the denominator of ΣH is, even though the molecular L _LC is small, large Therefore, there is a possibility of causing an error, so that such a short mileage is set to be excluded from the LC protection control according to the present invention. As an example, the protection control exclusion distance is set to a short distance of about several tens km.

  If YES in step S17, a predetermined value is preset in timers TM3 and TM4 in steps S18 and S19. The predetermined value preset in each of the timers TM1 to TM7 can be set to an arbitrary value for each timer.

If step S17 is NO, the routine of steps S20 to S23 is executed. In the routine of steps S20 to S23, processing corresponding to the function of the protection instruction unit 35 in FIG. 2 is executed. In step S20, checks whether the load slope S _LC is greater than the reference load tilt RS, if NO, the preset predetermined value to the timer TM3 at step S21. If step S20 is YES, it is checked in step S22 whether the value of the timer TM3 has become zero. If the value of the timer TM3 is not 0, the process goes to step S24. If the value of the timer TM3 becomes 0, the long-term LC load protection flag (F_LC load protection (long-term)) is set to 1 in step S23. With this configuration, as soon as the _LC load slope SLC becomes larger than the reference load slope RS, the F_LC load protection (long-term) is not set to 1, and the timer TM3 preset value is reduced. The F_LC load protection (long term) is set to 1 on condition that the state of S _LC > RS is maintained until a certain time until the count is completed.

The routines in steps S24 to S27 execute processing corresponding to the function of the short-term protection instruction means 39 in FIG. In step S24, checks whether the short-term load tilt sS _LC is greater than the short-term reference load tilt srs, if NO, the preset predetermined value to the timer TM4 in step S25. If YES in step S24, it is checked in step S26 whether the value of timer TM4 has become zero. If the value of the timer TM4 is not 0, the process goes to step S28. If the value of the timer TM4 becomes 0, the short-term LC load protection flag (F_LC load protection (short-term)) is set to 1 in step S27. With this configuration, as soon as the _LC short-term load slope sS _LC becomes larger than the short-term reference load slope sRS, the F_LC load protection (short-term) is not set to 1 and the timer TM4 is preset. The F_LC load protection (short term) is set to 1 on the condition that the state of sS _LC > sRS has continued until a certain time until the down-counting is completed.

  In step S28, it is checked whether any of F_LC temperature protection, F_LC heat generation protection, F_LC load protection (long term), and F_LC load protection (short term) is set to 1. If no flag is set to 1, step S36 goes from NO in step S28 to NO in step S31, goes through NO in step S34 in FIG. 4C, or goes from NO in step S34 to NO in step S35. In step S37, the timers TM6 and TM7 are preset with predetermined values, and the sequence is terminated.

  If any of F_LC temperature protection, F_LC heat generation protection, F_LC load protection (long-term), and F_LC load protection (short-term) is set to 1, the process goes from YES in step S28 to step S29, and the LC protection control flag (F_LC Protection control) is set to 1, and a predetermined value is preset in the timer TM5 in step S30. Next, in step S31, it is checked whether the LC protection control flag (F_LC protection control) is set to 1. If YES, it is checked in step S32 whether the current LC control state is slip control. If the slip control is being performed, the process goes to step S33 to change the LC control state to lock-up clutch OFF (LC OFF) (corresponding to the clutch operation control means 36).

  Thus, if the F_LC load protection (long term) or F_LC load protection (short term) flag is set to 1, the F_LC protection control flag is set to 1 to indicate that LC protection control should be performed. Then, the LC slip control is changed to LC OFF by the processing of steps S32 and S33, and the clutch operation is limited so as not to raise the surface temperature of the clutch friction material.

  Next, it is determined whether or not a predetermined LC protection control release condition is satisfied by the processing after step S34 shown in FIG. 4C. In step S34, it is checked whether the value of timer TM5 is zero. When the LC protection control is started, a predetermined value is preset in the timer TM5 (S30), the timer TM5 starts to count down, and thereafter, when a predetermined time corresponding to the preset predetermined value has elapsed, YES in step S34 It is determined. Therefore, once the LC protection control according to the present invention is started, the LC protection control state is maintained at least for a predetermined time by the timer TM5.

If the value of the timer TM5 is 0, it is confirmed in step S35 that F_LC protection control is 1 (that is, LC protection control = LC operation being restricted). If YES, the process proceeds to step S38. At step S38, the checks whether the current LC surface temperature T _LC is smaller than the positive value of the predetermined value to the hydraulic oil temperature TATF. Predetermined value plus a relatively small value, in short current LC surface temperature T _LC Do becomes smaller than a somewhat higher value than the current hydraulic oil temperature TATF, i.e., LC friction material than the hydraulic oil temperature TATF Check to see if it has been cooled to a somewhat high level. If YES, it is checked in step S39 whether the current vehicle speed Nv has become lower than the set vehicle speed. The set vehicle speed is a relatively small value, and the determination in step S39 is included in the release condition so that the LC protection control = LC operation restriction is not suddenly released while the vehicle is running.

At step S40, checks whether the load slope S _LC is smaller than the reference load tilt RS, if NO, the preset predetermined value to the timer TM6 in step S41. If step S40 is YES, it is checked in step S42 whether the value of the timer TM6 has become zero. If the value of the timer TM6 is not 0, the process goes to step S44. If the value of the timer TM6 becomes 0, the long-term LC load protection release flag (F_LC load protection (long-term) release) is set to 1 in step S43. This configuration, as soon as the load slope S _LC of the LC becomes smaller than the reference load tilt RS, without instructing the release of long-LC load protection, preset predetermined value amount of the down count timer TM6 has Instructing cancellation of long-term LC load protection (set F_LC load protection (long-term) cancellation to 1) on condition that the state of S _LC <RS has been maintained until a certain period of time elapses. It is like that.

At step S44, checks whether the short-term load tilt sS _LC is smaller than the short-term reference load tilt srs, if NO, the preset predetermined value to the timer TM7 in step S45. If YES in step S44, it is checked in step S46 whether the value of the timer TM7 has become zero. If the value of the timer TM7 is not 0, the process goes to step S48. If the value of the timer TM7 becomes 0, the short-term LC load protection release flag (F_LC load protection (short-term) release) is set to 1 in step S47. With this configuration, as soon as the _LC short-term load slope sS _LC becomes smaller than the short-term reference load slope sRS, the timer TM7 does not give an instruction to cancel the short-term LC load protection, and the timer TM7 decreases by a predetermined value. Instruct the cancellation of short-term LC load protection (set F_LC load protection (short-term) cancellation to 1) on condition that the state of sS _LC <sRS has continued until a certain time until the count is completed. To do).

  In step S48, it is checked whether both F_LC load protection (long-term) release and F_LC load protection (short-term) release flags are set to 1. If YES, it is checked in step S49 whether the accelerator pedal (AP) opening is equal to or less than the set accelerator pedal (AP) opening. The set accelerator pedal opening is a relatively small value, and the determination in step S49 is included in the cancellation condition so as not to cancel the LC protection control = LC operation restriction during the acceleration operation. If YES in step S49, it means that all conditions for releasing LC protection control = LC operation restriction are satisfied, and predetermined protection control release processing is performed in step S50. For example, in this protection control release process, all flags set in this sequence are reset to 0. As a result, the LC protection instruction is canceled, and it is permitted to perform slip control in the LC fastening control.

1 Engine 2 Automatic transmission 3 Torque converter 5 AT-ECU
6 Hydraulic control device 21 Crankshaft 22 Main shaft 30 Lockup clutch 31 Temperature calculation means 32 Load calculation means 33 Accumulation means 34 Inclination calculation means 35 Protection instruction means 36 Clutch operation control means 37 Short-term (second) accumulation means 38 Short-term ( Second) inclination calculation means 39 Short-term (second) protection instruction means

Claims (5)

Temperature calculating means for calculating the surface temperature of the clutch friction material in the lock-up clutch of the torque converter of the vehicle;
Load calculating means for calculating a thermal load applied to the clutch friction material based on the calculated surface temperature;
Accumulating means for accumulating the calculated thermal load to obtain a thermal load accumulated value of the clutch friction material;
Inclination calculating means for obtaining a load inclination by dividing the thermal load cumulative value by the cumulative travel distance of the vehicle;
Protection indication means for comparing the load slope with a predetermined reference load slope and instructing clutch protection when the load slope exceeds the reference load slope;
A lockup clutch protection control device in a torque converter, comprising: clutch operation control means for limiting clutch operation so as not to increase the surface temperature of the clutch friction material when the clutch protection is instructed. A second accumulating means for accumulating the calculated thermal load from the start of the engine in a predetermined low temperature environment to obtain a second thermal load accumulated value of the clutch friction material;
A second inclination calculating means for obtaining a second load inclination by dividing the second thermal load accumulated value by the vehicle travel distance from the accumulation start time;
A second protection indicating means for comparing the second load inclination with a predetermined second reference load inclination and instructing clutch protection when the second load inclination exceeds the second reference load inclination; The clutch operation control means limits the clutch operation so as not to increase the surface temperature of the clutch friction material even when the clutch protection is instructed by the second protection instruction means. The protection control apparatus of the lockup clutch in the torque converter of Claim 1. The protection instruction means instructs the clutch protection on the condition that the state where the load inclination exceeds the reference load inclination continues for a predetermined time or more,
The second protection instruction means instructs the clutch protection on the condition that a state in which the second load inclination exceeds the second reference load inclination has continued for a predetermined time or more. Item 3. The lockup clutch protection control device according to Item 1 or 2.   The clutch operation control means is set to a clutch protection control state based on the clutch protection instruction, and restricts the clutch operation to increase the surface temperature of the clutch friction material in the clutch protection control state. Furthermore, a predetermined time or more has elapsed since the clutch protection control state was set, the load gradient does not exceed the reference load gradient, and the second load gradient exceeds the second reference load gradient. The clutch protection control state is canceled when all of the following conditions are satisfied: the accelerator pedal opening is equal to or less than a predetermined value, and the vehicle speed is equal to or less than a predetermined value. Item 4. The lockup clutch protection control device according to any one of Items 1 to 3.   The predetermined reference load inclination is a value obtained by dividing a predetermined limit value of a cumulative thermal load value of the clutch friction material by a lifetime travel distance set as an ideal travel distance to use up the clutch friction material. The protection control device for a lock-up clutch according to any one of claims 1 to 4.

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