JP3998007B2 - Torque converter lockup control device - Google Patents

Description

  The present invention relates to a lockup control device for bringing a torque converter used, for example, inserted into a transmission system of an automatic transmission into a lockup state in which input / output elements are directly connected.

Since the torque converter performs power transmission between the input / output elements via the fluid, it performs a torque fluctuation absorbing function and a torque increasing function, but has a poor transmission efficiency.
For this reason, in a torque converter inserted in the transmission system of an automatic transmission for a vehicle, the torque converter can be used under a driving condition (in the lockup region) that does not require the torque fluctuation absorbing function and the torque increasing function. In a locked-up state where the input / output elements are mechanically directly connected by fastening the lock-up clutch, and under the other driving conditions (in the converter area), the torque converter is directly connected by releasing the lock-up clutch. Today, so-called lock-up torque converters that are in a converter state in which is released are frequently used.

  When performing lock-up control of this type of torque converter, conventionally, as described in Non-Patent Document 1, for example, a gain map having the throttle opening and the vehicle speed as parameters is estimated, thereby estimating the load state of the lock-up clutch, Conventionally, the lock-up clutch is controlled to be engaged according to the load state.

Incidentally, as described in Patent Document 1, the applicant of the present invention has conventionally provided a differential pressure control valve that electronically controls the differential pressure before and after the lockup clutch as described in Patent Document 1, and the differential pressure controlled thereby. A lockup clutch has been fastened so that the torque converter is brought into a lockup state in which the input / output elements are directly connected.
According to such a lockup control mechanism, the differential pressure across the lockup clutch, that is, the engagement force of the lockup clutch is uniquely determined by the control command to the differential pressure control valve regardless of the pressure change of the hydraulic oil toward the torque converter. As a result, it is possible to accurately control the fastening force of the lockup clutch, and it is also possible to perform accurate transient control.
Nissan Motor Co., Ltd. “NISSAN RE4R01A full range electronically controlled automatic transmission maintenance manual” (A261C07) published in March 1987 Japanese Patent Laid-Open No. 08-014381

  By the way, in the conventional lockup control system as described in Non-Patent Document 1, when the shift point is changed significantly, gain tuning is required for each shift point, and the matching man-hours are enormous. There was a big problem.

The first invention described in claim 1 uses a differential pressure control means that electronically controls the differential pressure itself of the lockup clutch as described in Patent Document 1, and provides a special lockup control device. , Without requiring enormous matching man-hours, while minimizing response delay, reducing lockup shock and preventing lockup clutch facing burning under any vehicle operating conditions,
In addition, at this time, depending on the vehicle operating condition, the lock-up clutch engagement speed becomes too slow, and there is a concern that judder of the lock-up clutch may occur. The purpose is to propose an up-control device.

  According to a second aspect of the present invention, the relationship between the control command to the differential pressure control means used in the first invention and the fastening torque capacity of the lock-up clutch is determined based on the source pressure of the differential pressure control means and the engine speed. It is an object of the present invention to be able to achieve the operation and effect of the first invention in a more accurate manner so as to be accurate regardless of changes in the above.

  In the third aspect of the present invention, the operational effect of the first aspect of the invention is further ensured by making the relationship between the control command and the fastening torque capacity accurate regardless of changes in the transmission hydraulic oil temperature. It aims to be able to be achieved.

  According to a fourth aspect of the present invention, the function and effect of the first aspect of the present invention can be obtained by making the relationship between the control command and the fastening torque capacity accurate even if the drive voltage of the differential pressure control means changes. It aims to be able to be achieved more reliably.

  The fifth aspect of the present invention is to propose a monitoring object of the vehicle operating state in which the operational effects of the first aspect of the invention are suitably achieved.

  According to a sixth aspect of the present invention, there is proposed a lockup control device for a torque converter that ensures that the function and effect of the first invention can be achieved even when the transmission torque of the torque converter changes during the lockup control process. The purpose is to do.

  According to a seventh aspect of the invention, the control command to the differential pressure control means changes remarkably rapidly as compared with the responsiveness of the lockup control mechanism, and the control command is executed after a large time delay. The purpose is to avoid the above unnaturalness.

For these purposes, first, the torque converter lockup control device according to the first aspect of the present invention is as follows.
A differential pressure control means for electronically controlling the differential pressure itself of the lockup clutch is provided, and the lockup clutch is fastened by the differential pressure controlled by the means to bring the torque converter into a lockup state in which the input / output elements are directly connected. In a lockup control device,
The control for reducing the engagement torque capacity to 0 based on the relationship between the control command to the differential pressure control means that has been obtained in advance and the engagement torque capacity of the lockup clutch of the soot obtained by the control command. Obtain the initial value of the command and the control command target value for the fastening torque capacity corresponding to the torque converter transmission torque,
The control command to the differential pressure control means at the time of lock-up of the torque converter, from the initial value of the control command to the target value of the control command, to reduce the engagement shock of the lock-up clutch and prevent the clutch facing from burning out for each vehicle operating state. Is configured to gradually increase at a corresponding time change gradient over a predetermined time period of
A lower limit value is set in the time change gradient of the control command so as not to cause a judder of the lockup clutch.

A torque converter lockup control device according to a second aspect of the present invention is the first aspect of the invention,
The relationship between the control command to the differential pressure control means and the engagement torque capacity of the lock-up clutch, which has been previously determined, is the original pressure of the differential pressure control means, the engine speed at the front stage of the torque converter, or both According to the above, it is characterized in that the configuration is modified so as to match the actual situation.

A torque converter lockup control device according to a third aspect of the present invention is the first invention or the second aspect,
The configuration in which the relationship between the control command to the differential pressure control means and the engagement torque capacity of the lock-up clutch, which has been obtained in advance, is corrected so as to consistently match the actual situation according to the transmission hydraulic oil temperature. It is a feature.

A torque converter lock-up control device according to a fourth aspect of the invention is any one of the first to third aspects of the invention.
The previously determined relationship between the control command to the differential pressure control means and the engagement torque capacity of the lock-up clutch is corrected so that it always matches the actual situation according to the drive voltage of the differential pressure control means. It is characterized by this.

A torque converter lock-up control device according to a fifth aspect of the invention is any one of the first to fourth aspects of the invention.
Any one of an engine throttle opening, a transmission input torque, and a torque converter slip amount may be used as the driving state of the vehicle, or any combination thereof may be used.

A torque converter lock-up control device according to a sixth aspect of the present invention, according to any one of the first to fifth aspects of the invention,
The torque converter transmission torque is configured so that the control command target value is always matched to the actual situation as the current torque converter transmission torque obtained in real time.

A torque converter lock-up control device according to a seventh aspect of the invention is the sixth aspect of the invention,
The present invention is characterized in that the time change rate of the control command to the differential pressure control means is limited.

The differential pressure control means electronically controls the differential pressure across the lockup clutch, and the lockup clutch is fastened by the electronically controlled differential pressure to bring the torque converter into a lockup state in which the input / output elements are directly connected.
By the way, in the first invention, based on the relationship between the control command to the differential pressure control means obtained in advance and the tightening torque capacity of the saddle lockup clutch obtained by this control command, this fastening torque capacity is determined. The control command target value for the fastening torque capacity corresponding to the initial value of the control command to zero and the torque converter transmission torque is obtained,
When the torque converter locks up, the control command to the differential pressure control means is changed from the initial value of the control command to the target value of the control command, so that the engagement shock reduction of the lockup clutch and the prevention of clutch facing burning are compatible. Are gradually increased at a corresponding time change gradient over a predetermined time.

For this reason, in the first aspect of the invention, the lockup clutch has its engagement torque capacity set to 0 at a stroke at the initial value of the control command, and the loss stroke not involved in the shock is quickly completed. Can be minimized.
Thereafter, the vehicle is operated so that both the reduction of the engagement shock of the lock-up clutch and the prevention of clutch facing burning can be achieved from the initial value of the control command to the control command target value having an engagement torque capacity corresponding to the torque converter transmission torque. In order to gradually increase over a predetermined time for each state,
Transient control that achieves both lock-up shock reduction and prevention of lock-up clutch facing burnout without requiring enormous matching man-hours can be realized under any vehicle operating condition, reducing the shock, In other words, the lockup can be completed in a manner that does not cause burnout of the lockup clutch facing.

In the first aspect of the present invention, the lower limit value is set so as not to cause the lockup clutch judder in the time change gradient of the control command.
As a result of trying to achieve transient control that achieves both lock-up shock reduction and prevention of lock-up clutch facing burning under any vehicle operating condition, the lock-up clutch engagement speed generates judder depending on the vehicle operating condition Even in such a case, the lockup clutch engagement speed that is too low is not permitted, and it is possible to prevent the judder of the lockup clutch from occurring.

In the second invention, the relationship between the control command to the differential pressure control means and the engagement torque capacity of the lock-up clutch, which has been obtained in advance, is calculated based on the original pressure of the differential pressure control means or the engine upstream of the torque converter. Depending on the number of revolutions, or both, it will be modified to match the actual situation.
The relationship between the control command and the fastening torque capacity used in the first invention becomes accurate regardless of the source pressure of the differential pressure control means and the change in the engine speed, and the above-mentioned effects of the first invention are more reliably achieved. can do.

In the third aspect of the invention, the relationship between the control command and the fastening torque capacity is corrected so as to be consistent with the actual situation according to the transmission hydraulic oil temperature.
The relationship between the control command and the fastening torque capacity is always accurate regardless of the change in the transmission hydraulic oil temperature, and it is possible to achieve the above-described operational effect of the first invention more reliably.

In the fourth invention, the relationship between the control command and the fastening torque capacity is corrected so as to be consistent with the actual situation according to the drive voltage of the differential pressure control means.
The relationship between the control command and the fastening torque capacity becomes accurate regardless of the change in the drive voltage, and the above-mentioned operational effect of the first invention can be achieved more reliably.

In the fifth aspect of the invention, any one of an engine throttle opening, a transmission input torque, and a torque converter slip amount is used as the driving state of the vehicle in the first aspect, or any combination thereof is used. From
The above-mentioned operation and effect in the first invention can be suitably achieved.

In the sixth invention, since the torque converter transmission torque used when obtaining the control command target value is the current torque converter transmission torque obtained in real time,
Even when the transmission torque of the torque converter changes in the lock-up control process, the control command target value to be obtained can be always matched with the actual situation, and the operational effect of the first invention can be achieved reliably.

In the seventh invention, the time change rate of the control command to the differential pressure control means is limited.
The control command to the differential pressure control means changes remarkably rapidly compared to the responsiveness of the lockup control mechanism, so that it is possible to avoid the unnaturalness in control such that the control command is executed after a large time delay. .

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 shows a drive system of a vehicle including a torque converter having a lock-up control device according to an embodiment of the present invention, wherein 1 is an engine as a prime mover, 2 is a torque converter, and 3 is a gear shift of an automatic transmission. The mechanism, 4 is a differential gear device, and 5 is a wheel, and these are sequentially driven and coupled as shown in the figure to constitute a vehicle drive system.

  A torque converter 2 for drivingly coupling the engine 1 to the gear transmission mechanism 3 includes a pump impeller 2a as an input element driven by the engine 1, and a turbine runner 2b as an output element coupled to the input shaft of the gear transmission mechanism 3. A so-called lockup type torque converter including a lockup clutch 2c that directly connects between the pump impeller 2a and the turbine runner 2b is provided.

Engagement force of the lock-up clutch 2c is determined by the differential pressure of the apply pressure P _A and the release pressure P _R at the front and rear (lockup clutch engagement differential pressure), if the apply pressure P _A is lower than the release pressure P _R, Rock The up clutch 2c is released so that the pump impeller 2a and the turbine runner 2b are not directly connected to each other, and the torque converter 2 is allowed to function in a converter state in which the slip is not limited.
When apply pressure P _A is larger than the differential pressure set value higher than the release pressure P _R, it is fastened lockup clutch 2c is eliminated relative rotation between the pump impeller 2a and the turbine runner 2b, and the torque converter 2 Make it work in the locked-up state.

In this embodiment, the following configuration the lock-up control system for determining the differential pressure (lock-up clutch engagement pressure difference) itself between apply pressure P _A and the release pressure P _R to perform the predetermined lock-up control.
However the lockup clutch engagement differential pressure (P _A -P _R) is a matter of course that may be determined by been described constituent elements described in the Patent Document 1.
The lock-up control valve 11 uses the line pressure P _L as a source pressure, and a differential pressure (P between the apply pressure P _A and the release pressure P _R according to the signal pressure P _S from the lock-up solenoid 13 duty-controlled by the controller 12. _A− P _R ), and the lockup control valve 11 and the lockup solenoid 13 constitute a differential pressure control means. The lockup control valve 11 and the lockup solenoid 13 are well-known in FIG. Shall be.

That is, it is assumed that the lockup solenoid 13 generates a signal pressure P _S corresponding to the lockup control command LUDty (ON duty) from the controller 12 using a constant pilot pressure P _p as a source pressure.
The lock-up control valve 11, along with receiving the above signal pressure P _S and the fed-back release pressure P _R in one direction, receives a spring force and fed back apply pressure P _A of the spring 11a in the other direction, the following Thus, differential pressure control is performed.
That, as is increasing the signal pressure P _S from the lock-up solenoid 13 with an increase in the lock-up control command LUdty (ON-duty), the difference between the lock-up control valve 11 apply pressure P _A and the release pressure P _R The pressure, that is, the lock-up clutch engagement differential pressure (P _A -P _R ) is increased as shown in FIG. 9A, and the lock-up clutch engagement pressure (P _A -P _R ) 2c can be fastened, and finally the torque converter is brought into a lock-up state with a differential pressure equal to or higher than the set value.
On the contrary, the lockup control valve 11 has a lockup clutch engagement differential pressure (P _A −P) as the signal pressure P _S from the lockup solenoid 13 is reduced as the lockup control command LUDty (ON duty) decreases. _R ) is reduced as shown in FIG. 9 (a) to lower the engagement force of the lockup clutch 2c, and finally the lockup clutch 2c is turned on by the negative value of the lockup clutch engagement differential pressure (P _A -P _R ). It is assumed that the torque converter 2 is in a converter state by releasing it.

Incidentally, the fastening torque capacity Tcap of the lock-up clutch 2c is determined by the above-mentioned lock-up clutch engagement differential pressure (P _A -P _R), facing the outer diameter r ₁ of the lock-up clutch 2c, the facing inner diameter r _2, facing the central When the diameter is r ₃ , the friction coefficient of the facing is μ, and the safety coefficient is K _S , the engagement torque capacity Tcap of the lockup clutch is expressed by the following equation.
Tcap = [(P _A −P _R ) (r ₁ ² −r ₂ ² ) × π × μ × r ₃ ] / K _S

Accordingly, the lockup clutch engagement differential pressure (P _A -P _R ) for determining the engagement torque capacity Tcap of the lockup clutch 2c as described above is a lockup control command to the solenoid 13 as shown in FIG. 9 (a). Since it is determined by LUDTY (ON duty),
The relationship between the engagement torque capacity Tcap of the lockup clutch and the lockup control command LUDty (ON duty) can be obtained in advance as indicated by LUC in FIG. 9B.

The controller 12 that determines the lock-up control command LUdty (ON duty) of the solenoid 13 stores the relationship between the fastening torque capacity Tcap and the lock-up control command LUDty shown in FIG. 9B, which will be described later. Contributes to lock-up control.
For the lockup control, the controller 12 sends a signal from the throttle opening sensor 21 for detecting the throttle opening TVO of the engine 1 and the engine speed N _e (torque as shown in FIGS. 1 and 2. A signal from the engine rotation sensor 22 for detecting the converter input rotation speed), a signal from the turbine rotation sensor 23 for detecting the rotation speed N _t (torque converter output rotation speed) of the turbine runner 2b, and a transmission output rotation speed N. A signal from the transmission output rotation sensor 24 that detects _o and a signal from the oil temperature sensor 25 that outputs a voltage value ADatf corresponding to the transmission hydraulic oil temperature are input.

The controller 12 executes the control program shown in FIGS. 3 to 5 on the basis of the input information, and performs the lock-up control of the torque converter 2 through the lock-up control command LUDty as follows.
3A shows a signal measurement process, FIG. 3B shows a lockup control process, and FIG. 3C shows a signal output process.

3A, first, at step 31, the throttle opening TVO, the engine speed N _e , the transmission input speed N _t , the transmission output speed N _o , and the oil temperature sensor output value. Read ADatf.
Next, at step 32, the torque converter input / output rotational deviation absolute value | N _e −N _t | is obtained and set to N _err .
From the oil temperature sensor output value ADatf, the transmission operating oil temperature Temp is obtained based on the map corresponding to FIG.
From the throttle opening TVO and the engine speed N _e, together determine the engine torque T _e based on the engine performance diagram obtained in advance, to be seen from the speed ratio of the torque converter 2 (N _t / N _e) Multiplying the torque ratio t to obtain the transmission input torque Tin,
The vehicle speed VSP is obtained by multiplying the transmission output speed N _o by a constant K.

In the lock-up control of FIG. 3B, first, in step 33, it is determined whether or not the lock-up should be performed by the processing described later with reference to FIG. 4, and then in step 34, the lock-up control based on the determination is performed as shown in FIG. As will be described later.
The signal output process of FIG. 3C is a process of outputting the lockup control command LUDty determined by the lockup control of FIG.

To explain the lock-up determination in FIG. 4, in step 41, the transmission hydraulic oil temperature Temp is higher than the set temperature Tmpth at which the torque converter 2 should be allowed to be locked up, or less than the set temperature Tmpth at which the lock-up should be prohibited. Determine whether the temperature is low.
If the temperature is high enough to permit lock-up, it is determined in step 42 whether the lock-up area determination flag LU is 0 or not, whether it was the previous converter area or the previous lock-up area.

If it is the previous converter area, it is determined in steps 43 and 44 whether or not the lockup area on the right side of the lockup ON line LUTon indicated by the solid line in FIG.
That is, first, at step 43, the lockup ON opening TVOon on the lockup ON line LUTon indicated by the solid line in FIG. 8 is retrieved from the vehicle speed VSP as illustrated in FIG.
Next, at step 44, it is determined whether or not the vehicle has entered the current lock-up region based on whether or not the throttle opening TVO is less than the lock-up ON opening TVOon.

When it is determined that the lock-up area has been entered this time, in step 45, the lock-up area determination flag LU is set to 1 so as to indicate this, thereby contributing to the determination in the next step 42.
Therefore, if it is determined in step 44 that the lockup area is not yet entered, the control is terminated as it is, so that the lockup area determination flag LU remains 0, and the determination in the next step 42 is performed. To contribute.

When it is determined in step 42 that the previous lock-up area has been reached, it is determined in steps 46 and 47 whether or not the converter area has entered the left side of the lock-up OFF line LUToff indicated by the broken line in FIG.
That is, first, in step 46, the lockup OFF opening TVOoff on the lockup OFF line LUToff indicated by the broken line in FIG. 8 is searched from the vehicle speed VSP as illustrated in FIG.
Next, at step 47, it is determined whether or not the current time has entered the converter region based on whether or not the throttle opening TVO is equal to or greater than the lockup OFF opening TVOoff.

When it is determined that the converter area has been entered this time, in step 48, the lockup area determination flag LU is reset to 0 to indicate this, which contributes to the determination in the next step 42, and from the converter area as described later. An initialization flag FLGf for initialization when switching to the lockup area is reset to zero.
Therefore, when it is determined in step 47 that the converter area is not yet entered, the control is terminated as it is, so that the lockup area determination flag LU is maintained at 1 to contribute to the determination in the next step 42. .

  When it is determined in step 41 that the transmission hydraulic fluid temperature Temp is a low temperature at which lockup should be prohibited, steps 42 to 47 are skipped and only step 48 is executed, and the lockup region determination flag LU is reset to 0. At the same time, the initialization flag FLGf is reset to zero.

The lockup control in step 34 of FIG. 3B based on the lockup region determination result will be described in detail with reference to FIG. 5. First, in step 51, whether or not the lockup region determination flag LU is “1” is determined by: Check lock area or converter area.
If the converter region is LU = 0, the control is terminated as it is to place the torque converter 2 in the converter state. If the lock-up region is LU = 1, the lock-up control of the torque converter 2 is executed as follows. .

That is, first, at step 52, it is determined whether or not the initialization flag FLGf is zero.
Since the initialization flag FLGf is reset to 0 in step 48 of FIG. 4 when entering the converter area, the control proceeds from step 52 to the initial setting process in step 53, and then in step 54, the initialization flag FLGf is reset. After performing the process of setting FLGf to 1, the control is terminated.
For this reason, the initial setting in step 53 is executed only once at the beginning of entering the lockup area, and thereafter, the initialization flag FLGf is set to 1 in step 54, so step 53 is controlled to steps 55 to 59. The lockup control described later is performed by proceeding with the above.

In order to explain the initial setting in step 53, the engagement torque capacity Tcap of the lockup clutch 2c and the lockup control command LUdty (ON) to the solenoid 13 illustrated in FIG. The lockup control command initial value LUDi for the initial capacity LUC (0) corresponding to the engagement torque capacity Tcap = 0 is obtained based on the relationship with the duty), and the speed change obtained in step 32 of FIG. A lockup control command target value TCAPdty for the fastening torque capacity Tcap = LUC (Tin) corresponding to the machine input torque Tin (torque converter transmission torque) is obtained.
Next, the lockup required time LUTIM for increasing the engagement torque capacity Tcap of the lockup clutch 2c from the initial capacity LUC (0) to the target capacity LUC (Tin) corresponding to the transmission input torque Tin is read.
However, this lock-up time LUTIM is a time that balances the trade-off relationship between lock-up clutch engagement shock reduction and prevention of clutch facing burning due to heat generation. I shall keep it.

Then, by dividing the step (TCAPdty-LUDi) between the lockup control command target value TCAPdty and the lockup control command initial value LUDi by the lockup required time LUTIM, the engagement torque capacity Tcap is set to the initial capacity LUC ( 0) to the target capacity LUC (Tin) over the lockup required time LUTIM, the time change gradient DFFdty of the lockup control command LUdty is calculated.
Further, DFFdty is selected by selecting the larger max (DFFdty, DFFmin) between the time variation gradient DFFdty of the lockup control command and the lower limit value DFFmin of the time variation gradient of the lockup control command in which the lockup clutch 2c does not cause judder. To prevent the lockup clutch 2c from being judled so that the time-varying gradient DFFdty of the lockup control command LUdty does not become smaller than the lower limit value DFFmin.

Finally, the lockup control command initial value LUDi is set to the lockup control command LUDty, and this is output to the lockup solenoid 13 at step 35 in FIG.
Therefore, as shown in FIG. 10, the lockup control command LUdty corresponds to the fastening torque capacity Tcap = 0 at a stroke instant t ₁ from the converter area to the lockup area where the lockup area flag LU switches from 0 to 1. The control command initial value LUDi for the initial capacity LUC (0) is increased, and the lockup clutch 2c can quickly complete the loss stroke not involved in the shock, thereby preventing a lockup response delay.

After the second loop after the first loop is completed, in step 55, the torque converter input / output rotational deviation absolute value N _err = | N _e −N _t | obtained in step 32 of FIG. It is determined whether the lamp control range is equal to or greater than the set value Nth or the lamp fixed range.
In step 56, if the lamp control area, the step of the time to lock-up control instruction LUdty as at the instant t ₁ subsequent 10 change gradient DFFdty = max (DFFdty, DFFmin) is increased in this FIG. 3 (c) At 35, output to the lock-up solenoid 13.
Then, after the instant t _{2 in} FIG. 10 in which the absolute value of the torque converter input / output rotation deviation N _err = | N _e −N _t | Until it is determined that the lock-up control command LUdty has reached the set duty Dtyth, the lock-up control command LUdty is increased at a fast fixed time change gradient RMP2 at step 58, and this is increased at step 35 of FIG. Then, the lockup solenoid 13 outputs the lockup control command LUdty with a slightly slow fixed time change gradient RMP1, and outputs it to the lockup solenoid 13 in step 35 of FIG.

Therefore, after the instant t _{1 in} FIG. 10, the lock-up control command LUDty is reduced from the control command initial value LUDi for the initial capacity LUC (0) corresponding to the engagement torque capacity Tcap = 0, until instant t ₂ over a predetermined aforementioned lockup time required LUTIM to clutch facings prevent burnout are compatible, the fastening torque capacity corresponding to the transmission input torque Tin (torque converter transmission torque) Tcap = LUC ( (Tin) is gradually increased with a time-varying gradient DFFdty corresponding to the lock-up control command target value TCAPdty,
Without requiring enormous matching man-hours, it is possible to achieve transient control that achieves both reduction of lock-up shock and prevention of burn-up of lock-up clutch facings. Lock-up can be completed in a manner that does not cause burn-up of the up-clutch facing.

It should be noted that the relationship between the lockup control command LUDTY obtained in advance illustrated in FIG. 9B and the engagement torque capacity Tcap of the lockup clutch is designed so that the line pressure P _L that is the original pressure of the lockup control valve 11 is designed. These conditions change when the pressure value drops below the time value, when the leakage flow rate of the valve increases, or when the oil amount balance deteriorates, and the above lock-up control becomes inaccurate. A map is provided with the line pressure P _L , which is the original pressure of the lockup control valve 11, the engine speed N _e , or both, as parameters, and this is always corrected to match the actual situation. good.
In this case, changes in the line pressure P _L as the original pressure of the lock-up control valve 11, regardless of the change in speed N _e of the engine, and obtained by performing the lock-up control of the constantly aim street, by this The above effects can be achieved more reliably.

Further, the relationship between the lockup control command LUDTY obtained in advance illustrated in FIG. 9B and the engagement torque capacity Tcap of the lockup clutch is such that the friction coefficient μ of the lockup clutch facing depends on the transmission hydraulic oil temperature Temp. Therefore, even if the transmission hydraulic oil temperature Temp is changed, it is preferable to change the transmission hydraulic oil temperature so that it always matches the actual situation.
In this case, regardless of the transmission hydraulic oil temperature Temp, the above-described lockup control can always be performed as intended, and the above-described operational effects can be achieved more reliably.

Furthermore, since the relationship between the lockup control command LUDTY obtained in advance illustrated in FIG. 9B and the engagement torque capacity Tcap of the lockup clutch also varies depending on the drive voltage of the lockup solenoid 13, the drive voltage Even if it changes, it is good to make it different so that it may consistently match the actual situation.
In this case, regardless of the drive voltage of the lock-up solenoid 13, the above-described lock-up control can always be performed as intended, and the above-described operational effects can be achieved more reliably.

The lockup time LUTIM (see FIG. 10) is preferably longer to reduce the engagement shock of the lockup clutch. However, in this case, there is a possibility that the clutch facing increases the heat generation amount and burns out. In order to prevent clutch facing burning due to the heat generation, it is preferable to shorten the lock-up required time LUTIM.
Therefore, there is a trade-off relationship between the reduction of the engagement shock of the lockup clutch and the prevention of clutch facing burning due to heat generation, and as described above, determining the lockup required time LUTIM so that they are balanced with each other, Because the preferred lockup time LUTIM for that varies depending on the driving state of the vehicle,
The lock-up required time LUTIM varies depending on any one of the throttle opening TVO, transmission input torque Tin, torque converter slip amount N _err = | N _e −N _t |, or any combination thereof. I will let you.
For example, when the throttle opening TVO is low and the rotational change is small, the lock-up clutch engagement shock tends to be conspicuous. Therefore, in this state, the lock-up required time LUTIM is set longer, and conversely In a state where the throttle opening TVO is a large opening and the rotational change is large, it is preferable to set the lockup required time LUTIM shorter than the lockup clutch engagement shock by giving priority to preventing the clutch facing from burning.
As described above, when the lockup time LUTIM is made variable so that the engagement shock reduction of the lockup clutch and the prevention of clutch facing burning due to heat generation are balanced in accordance with the driving state of the vehicle, Regardless of this, it is possible to always achieve both reduction of the engagement shock of the lock-up clutch and prevention of clutch facing burning due to heat generation.

In the above embodiment, in step 53 of FIG. 5, the lockup control command target value TCAPdty corresponding to the transmission input torque Tin when the converter region is shifted to the lockup region is obtained, and this is calculated as the corresponding lockup. We decided to use it continuously during the control period.
In this case, the lockup control command target value TCAPdty does not accurately correspond to the current transmission input torque Tin during the short lockup control period and when the engine output torque changes.
Therefore, the lockup control command target value TCAPdty is preferably obtained from time to time based on the transmission input torque Tin detected in real time.

FIG. 6 shows another embodiment of the present invention that makes this possible. Step 53 for the initial setting in the control program of FIG. 5 is replaced with an initial setting such as step 61, and steps 62 to 64 are replaced. It is added.
The initial setting in step 61 is obtained by removing the items for calculating the lockup control command target value TCAPdty from the initial setting items in step 53 of FIG. 5, and the initial capacity LUC (0) corresponding to the fastening torque capacity Tcap = 0. The lockup control command initial value LUDi is obtained, then the lockup required time LUTIM is read, and finally the lockup control command initial value LUDi is set to the lockup control command LUDty. This is the step 35 in FIG. To output to the lockup solenoid 13.

Step 62 is repeatedly executed prior to the determination of Step 55 from the time when it is determined that the second and subsequent times after the initial setting is made in Step 52. In Step 32 of FIG. The lockup control command target value TCAPdty for the engagement torque capacity Tcap = LUC (Tin) corresponding to the transmission input torque Tin (torque converter transmission torque) obtained in real time is obtained from FIG. 9B.
Next, by dividing the step (TCAPdty-LUDi) between the lockup control command target value TCAPdty and the lockup control command initial value LUDi by the lockup required time LUTIM, the engagement torque capacity Tcap is set to the initial capacity LUC (0). The time change gradient DFFdty of the lockup control command LUdty for gradually increasing to the target capacity LUC (Tin) over the required lockup time LUTIM is calculated.
Further, DFFdty is selected by selecting the larger max (DFFdty, DFFmin) between the time variation gradient DFFdty of the lockup control command and the lower limit value DFFmin of the time variation gradient of the lockup control command in which the lockup clutch 2c does not cause judder. To prevent the lockup clutch 2c from being judled so that the time-varying gradient DFFdty of the lockup control command LUdty does not become smaller than the lower limit value DFFmin.

Steps 63 and 64 are sequentially executed after step 56, step 58, or step 59.
However, in this embodiment, the lockup control command LUDty obtained in steps 56, 58 and 59 is not used as it is as a signal output to the lockup solenoid 13 in step 35 of FIG. Then, the lockup control command LUDTY after the time change rate is limited in step 63 as described below is output to the lockup solenoid 13 in step 35 of FIG.
In step 63, using the weighting coefficient Kr between the current lockup control command LUDty and the previous lockup control command LUold,
(Ludty + LUold × Kr) / (Kr + 1) → Ludty
As a result of the above calculation, the lockup control command LUDty after the time change rate is limited is obtained, and this is output to the lockup solenoid 13 in step 35 of FIG.
In step 64, the limited lock-up control command LUdty is set in LUold, which contributes to the next calculation in step 63.

In this embodiment, as in step 62, the transmission input torque Ti (torque converter transmission torque) used when obtaining the lockup control command target value TCAPdty is the current detected torque obtained in real time.
Even when the transmission input torque Ti (torque converter transmission torque) changes in the lock-up control process, the lock-up control command target value TCAPdty to be obtained can always be matched to the actual situation, and the operation in the above-described embodiment The effect can always be ensured.

  Further, since the time change rate of the lock-up control command LUDty is limited by the coefficient Kr as in step 63, there is a situation where the lock-up control command LUdty changes remarkably rapidly compared with the response of the lock-up control mechanism. Occurrence can be avoided, and thus unnatural control can be avoided such that the control command is executed after a large time delay.

1 is a schematic system diagram showing a vehicle drive system including a lockup control device according to an embodiment of the present invention and a control system thereof. It is a system diagram which shows the lockup control system of the torque converter in the Example. The main routine of the lockup control which a controller performs in the same Example is shown, (a) is a flowchart of a signal measurement process, (b) is a flowchart of a lockup control process, (c) is a flowchart of a signal output process. It is. It is a flowchart which shows the subroutine of the lockup judgment process in the Example. It is a flowchart which shows the subroutine of the lockup control process in the Example. It is a flowchart regarding the subroutine of the lockup control process which shows the other Example of this invention. It is a relationship diagram of an oil temperature sensor value and oil temperature. It is a diagram which illustrates the lockup area | region of a torque converter. FIG. 2 is an operational characteristic of the lockup control system of the torque converter shown in FIG. 2, (a) is a diagram showing a relationship between a control command to the lockup solenoid and a lockup clutch engagement differential pressure, and (b) is a lockup control system. It is a diagram which shows the relationship between the control command to a solenoid, and the fastening torque capacity of a lockup clutch. It is an operation | movement time chart of the lockup control by this invention.

Explanation of symbols

1 Engine 2 Torque converter
2a Pump impeller (input element)
2b Turbine runner (output element)
2c Lock-up clutch 3 Gear transmission mechanism 4 Differential gear device 5 Wheel
11 Lock-up control valve (Differential pressure control means)
12 Controller
13 Lock-up solenoid (Differential pressure control means)
21 Throttle opening sensor
22 Engine rotation sensor
23 Turbine rotation sensor
24 Transmission output rotation sensor
25 Oil temperature sensor

Claims (7)

A differential pressure control means for electronically controlling the differential pressure itself of the lockup clutch is provided, and the lockup clutch is fastened by the differential pressure controlled by the means to bring the torque converter into a lockup state in which the input / output elements are directly connected. In a lockup control device,
The control for reducing the engagement torque capacity to 0 based on the relationship between the control command to the differential pressure control means that has been obtained in advance and the engagement torque capacity of the lockup clutch of the soot obtained by the control command. Obtain the initial value of the command and the control command target value for the fastening torque capacity corresponding to the torque converter transmission torque,
The control command to the differential pressure control means at the time of lock-up of the torque converter, from the initial value of the control command to the target value of the control command, to reduce the engagement shock of the lock-up clutch and prevent the clutch facing from burning out for each vehicle operating state. Is configured to gradually increase at a corresponding time change gradient over a predetermined time period of
A lockup control device for a torque converter, wherein a lower limit value is set in the time change gradient of the control command so as not to cause judder of a lockup clutch.   The lockup control device according to claim 1, wherein the relationship between the control command to the differential pressure control means and the engagement torque capacity of the lockup clutch, which has been obtained in advance, is the original pressure or torque of the differential pressure control means. A lockup control device for a torque converter, characterized in that a correction is made so as to match the actual situation in accordance with the number of revolutions of the engine in the previous stage of the converter, or both.   The lockup control device according to claim 1 or 2, wherein the relationship between the control command to the differential pressure control means and the engagement torque capacity of the lockup clutch, which has been obtained in advance, depends on the transmission hydraulic oil temperature. The torque converter lock-up control device is configured to be corrected so as to be consistent with the actual situation.   The lockup control device according to any one of claims 1 to 3, wherein the relationship between the control command to the differential pressure control means and the engagement torque capacity of the lockup clutch, which has been obtained in advance, is expressed as a differential pressure. A lockup control device for a torque converter, characterized in that a correction is made so as to always match the actual situation in accordance with the drive voltage of the control means.   5. The lockup control device according to claim 1, wherein any one of an engine throttle opening, a transmission input torque, and a torque converter slip amount is used as an operation state of the vehicle, or A lockup control device for a torque converter, characterized in that any combination thereof is used.   The lockup control device according to any one of claims 1 to 5, wherein the torque command transmission torque is the current torque converter transmission torque obtained in real time, and the control command target value is always matched to the actual situation. A lockup control device for a torque converter, characterized by comprising:   7. The lockup control device for a torque converter according to claim 6, wherein the lockup control device for the torque converter is configured to limit a time change rate of a control command to the differential pressure control means.

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