JP2007071276A - Slip controller for torque converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To return a lock up clutch into a slip condition quickly when the lock up clutch is unintentionally tightened during slip control. <P>SOLUTION: This slip controller for the torque converter controls tightening force of the lock up clutch like steps (S16 to S19) when slip rotational speed is reduced below a first predetermined value being smaller than target slip rotational speed during control (S4, S8) to let slip rotational speed agree with the target slip rotational speed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a torque converter, and more particularly to control when a lock-up clutch is engaged in a slip state.

  The lock-up control device for the torque converter inserted in the driving force transmission system of the automatic transmission including the continuously variable transmission is used to increase the torque and reduce the fuel consumption caused by the slip of the torque converter. In an operation region that does not require the shock absorbing function, the input / output elements of the torque converter are directly connected using a lock-up clutch. This is called the lock-up mode. In addition to this, the converter mode that completely releases the input and output elements and transmits torque via the fluid, and the slip that makes the lock-up clutch semi-engaged and maintains the predetermined slip state. There are three modes, which can be switched appropriately according to the driving state of the vehicle. This mode switching is performed by changing the lockup differential pressure, and the converter mode is set for the minimum pressure and the lockup mode is set for the maximum pressure.

In such a torque converter, by subtracting the converter torque corresponding to the target slip rotation from the engine torque, the lockup capacity necessary to realize the target slip rotation speed is calculated and converted into a differential pressure command value. Patent Document 1 discloses a technique for performing slip control so that the actual slip rotation speed matches the target slip rotation speed.
Japanese Patent Laid-Open No. 11-82726

  However, if the driver decreases the accelerator depression amount and the lockup capacity cannot follow the engine torque change, the actual slip rotation speed will fall below the target slip rotation speed and the lockup capacity will be excessive. There is a possibility that the lock-up clutch is engaged.

  Further, in a region where the lockup clutch is almost engaged, there is a dead zone where the actual engagement force does not operate linearly with respect to the command value because the engagement force of the lockup clutch has a hysteresis characteristic. In this case, even if the engagement force of the lockup clutch is gently operated, the actual engagement force does not change and the slip rotation speed may not be controlled linearly.

  An object of the present invention is to quickly return a lock-up clutch to a slip state when the lock-up clutch is unintentionally engaged during slip control.

  When the slip rotation speed falls below a first predetermined value smaller than the target slip rotation speed during the control so that the slip rotation speed matches the target slip rotation speed, the slip converter of the torque converter according to the present invention The fastening force is controlled so as to decrease stepwise.

  According to the present invention, when it can be determined that the lockup clutch has been engaged unintentionally during the slip control, the engagement force of the lockup clutch is reduced stepwise, so that the engagement state of the lockup clutch is changed to the slip state. It can be quickly returned. Further, even if there is a hysteresis characteristic for the fastening force of the lockup clutch, it is possible to quickly shift to a region where the fastening force can be controlled linearly.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration schematic diagram of a slip converter for a torque converter according to the present invention.

  The torque converter 1 is interposed between the engine 14 and the transmission 15 and transmits the driving force of the engine 14 to the transmission 15 via a fluid. The transmission 15 is an automatic transmission, and the driving force transmitted to the transmission 15 is transmitted to the drive wheels 16 via a final reduction gear (not shown).

  In the torque converter 1, a pump impeller 12 connected to the output shaft of the engine 14 and a turbine runner 13 connected to the input shaft of the transmission 15 are arranged to face each other. When the pump impeller 12 rotates with the rotation of the engine 14, the fluid (ATF) filled in the torque converter 1 flows, whereby the turbine runner 13 rotates. The torque converter 1 further includes a lockup clutch 2 that rotates together with the turbine runner 13.

  When the lockup clutch 2 is fastened to the pump impeller 12, the torque converter 1 is directly connected to the input element and the output element of the torque converter and enters a lockup state. In addition, when the input element and the output element are in a semi-fastened state, a slip state occurs in which slip occurs between the input element and the output element. When the lockup clutch 2 is completely released, the converter state is established.

  The lockup clutch 2 corresponds to a differential pressure ΔP (= PA−PR) between a torque converter apply pressure PA (hereinafter referred to as “apply pressure PA”) and a torque converter release pressure PR (hereinafter referred to as “release pressure PR”) acting on both sides thereof. Operate. The lockup clutch 2 is released when the release pressure PR is higher than the apply pressure PA, and is engaged when the release pressure PR is lower than the apply pressure PA.

  The torque that can be transmitted by the lockup clutch of the torque converter that depends on the fastening force of the lockup clutch 2, that is, the lockup capacity, is determined by the differential pressure ΔP. As the differential pressure ΔP increases, the fastening force of the lockup clutch 2 increases and the lockup capacity increases. The differential pressure ΔP is controlled by the lockup control valve 3.

  The lockup control valve 3 controls the differential pressure ΔP by controlling the apply pressure and the release pressure that act on the lockup clutch 2. The lockup control valve 3 is applied with the apply pressure PA and the release pressure PR facing each other, and further, the urging force of the spring 3a is applied in the same direction as the apply pressure PA, and from the lockup solenoid 4 in the same direction as the release pressure PR. The supplied signal pressure PS is applied. The differential pressure ΔP is determined so that the hydraulic pressure and the biasing force of the spring are balanced.

  The lockup solenoid 4 generates a signal pressure PS in accordance with the lockup duty D transmitted from the controller 5 with the pump pressure PP as an original pressure.

  A power supply voltage sensor 6 for detecting the power supply voltage, a pump impeller rotation sensor 7 for detecting the rotation speed of the pump impeller 12, a turbine runner rotation sensor 8 for detecting the rotation speed of the turbine runner 13, and an output shaft rotation speed of the transmission 15 are detected. The transmission output shaft rotation sensor 9 that performs the detection, the throttle opening sensor 10 that detects the throttle opening, and the ATF temperature sensor 11 that detects the temperature of the ATF transmit the detected values to the controller 5.

  The controller 5 determines the drive duty D of the lockup solenoid 4 and controls the lockup duty D according to the power supply voltage signal in order to control the engagement state of the lockup clutch 2 based on the received signal. .

  Next, the control performed by the controller 5 will be described with reference to the block diagram of FIG. 2 and the flowchart of FIG. These controls are performed every 20 ms, for example.

First, the slip control will be described with reference to FIG. The target slip rotation speed calculation unit 100 outputs a target slip rotation speed command value ω _SLPT based on the vehicle speed, the throttle opening, the transmission gear ratio of the transmission 15 and the ATF temperature. The target slip rotation speed command value ω _SLPT is calculated so as to _minimize the occurrence of torque fluctuations and _squeak noise, and the vehicle speed, throttle opening, transmission gear ratio and ATF temperature, target slip rotation speed ω _SLPT and This relationship is obtained in advance by experiments or the like.

The actual slip rotation speed calculation unit 101 subtracts the rotation speed ω _TR of the turbine runner 13 from the rotation speed ω _IR of the pump impeller 12 and outputs the actual slip rotation speed ω _SLPR of the torque converter 1. Here, the rotational speed of the pump impeller 12 is equivalent to the engine rotational speed, and the rotational speed of the turbine runner 13 is equivalent to the primary rotational speed.

The precompensators 102A and 102B output the target slip rotation speed correction value by passing the target slip rotation speed command value ω _SLPT through a compensation filter set so as to be a response intended by the designer.

The pre-compensator 102A calculates the first target slip rotation speed command value ω _{SLPTC1 based} on the following equation (1).

G _R (s) is a reference model and sets a transfer function so that a target response intended by the designer can be obtained.

The pre-compensator 102B calculates the second target slip rotation speed command value ω _{SLPTC2 based} on the following equation (2).

Here, G _M (s) = G _R (s) / P (s), where G _M (s) is a feedforward compensator, and P (s) is a modeled transmission of a slip rotation part to be controlled. It is a function.

The slip rotation speed deviation calculation unit 103 outputs a slip rotation speed deviation ω _SLPER based on the first target slip rotation speed correction value ω _SLPTC1 and the actual slip rotation speed ω _SLPR . The slip rotation speed deviation ω _SLPER is calculated based on the following equation (3).

The slip rotation speed command value calculation unit 104 uses a feedback compensator configured by proportional / integral control (hereinafter referred to as “PI control”) to eliminate the slip rotation speed deviation ω _SLPER , according to the following equation (4). 1 slip rotation speed command value ω _SLPC1 is calculated.

Here, K _P is a proportional control constant, K _I is an integral control constant, and s is a differential operator.

Further, the slip rotation speed command value ω _SLPC is calculated according to the following equation (5).

The slip rotation speed gain calculation unit 105 outputs a slip rotation speed gain g _SLP based on the rotation speed ω _TR of the turbine runner 13 with reference to the table of FIG.

The target converter torque calculator 106 outputs the target converter torque t _CNVC based on the slip rotation speed command value ω _SLPC and the slip rotation speed gain g _SLP . The target converter torque t _CNVC is calculated according to the following equation (6).

The engine output torque estimation unit 107 searches the engine torque map value t _ES based on the throttle opening degree Tvo and the engine speed Ne with reference to the map of FIG. Further, an estimated engine torque value t _EH is calculated according to the following equation (7) based on the engine torque t _ES .

Here, T _ED is a time constant of a first-order lag.

Target lockup capacity calculation unit 108 outputs the target lockup capacity t _LU on the basis of the target converter torque t _CNVC and the engine torque estimated value t _EH. The target lockup capacity t _LU is calculated based on the following equation (8).

The lockup clutch engagement pressure command value calculation unit 109 outputs a lockup clutch engagement pressure command value P _LUC based on the target lockup capacity t _LU with reference to the map of FIG.

The solenoid drive signal calculation unit 110 outputs a lockup duty S _DUTY based on the lockup clutch engagement pressure command value _PLUC . The lockup duty S _DUTY is calculated so that the engagement pressure of the lockup clutch 2 becomes the lockup clutch engagement pressure command value _PLUC . The relationship between the lockup clutch engagement pressure command value _PLUC and the lockup duty S _DUTY is obtained in advance by experiments or the like.

  Next, referring to FIG. 3, the control when the lockup clutch is stuck during the slip control, that is, when it is almost unintentionally engaged is described.

  In step S1, it is determined whether or not the control is started. If it is the start time, the process proceeds to step S2, and if it is not the start time, the process proceeds to step S3.

  In step S2, a flag used in this control is initialized. That is, the flag fRE_REC = 0, the timer TMR1 = T1, TMR = T2, and TMR3 = T3. Each flag and timer will be described later.

  In step S3, it is determined whether or not a lockup clutch sticking release request flag fRE_REC is zero. If it is 0, it will progress to step S4, and if it is 1, it will progress to step S11.

In step S4, it is determined whether or not the actual slip rotation speed ω _SLPR is smaller than a predetermined value SLP1 (first predetermined value). If it is smaller than the predetermined value SLP1, the process proceeds to step S5, and if it is not less than the predetermined value SLP1, the process proceeds to step S6. Here, the predetermined value SLP1 is a value for determining whether or not the actual slip rotation speed has become substantially zero in order to determine whether or not the lockup clutch 2 is unintentionally engaged. It is set to a value smaller than the speed ω _SLPT , for example, about a quarter of the target slip rotation speed ω _SLPT .

  In step S5, the timer TMR1 (first predetermined time) is counted down. Here, the predetermined time T1, which is the initial value of the timer TMR1, is preferably set to a value larger than the response delay or advance of the actual engine torque and the actual lockup fastening force.

In step S6, a slip rotation speed change amount Δω _SLP at a predetermined time Ts is calculated.

In step S7, a hysteresis estimation lockup clutch engagement pressure PLUC_HYS is calculated. Hysteresis estimated lockup clutch engagement pressure PLUC_HYS is set to the lock-up clutch engagement pressure P _LUC previous time.

  In step S8, it is determined whether or not the timer TMR1 is zero. If it is zero, it will progress to step S9, and if it is not zero, it will progress to step S10.

  In step S9, the lockup clutch sticking release request flag fRE_REC is set to 1.

  In step S10, the normal slip control shown in FIG. 2 is performed.

  On the other hand, when it is determined in step S3 that the lockup clutch tension release request flag fRE_REC is not zero, in step S11, the timer TMR3 (second predetermined time, fourth predetermined time) is counted down.

In step S12, it is determined whether or not the actual slip rotation speed ω _SLPR is greater than a predetermined value SLP2 (second predetermined value, third predetermined value). If it is larger, the process proceeds to step S14, and if it is equal to or smaller than the predetermined value SLP2, the process proceeds to step S13. Here, the predetermined value SLP2 is set to a slip rotation speed at which it can be determined that slip control is possible, and is, for example, about three- _fourths of the target slip rotation speed ω _SLPT .

  Note that it may be determined that the lock-up clutch has started to slip when the condition of step S12 continues for a predetermined time T4. At this time, it is preferable that the predetermined time T4 is set to a value larger than the response delay or advance of the actual engine torque and the actual lockup fastening force in the same manner as the predetermined time T1.

  In step S13, it is determined whether or not the timer TMR3 is zero. If it is zero, it will progress to step S14, and if it is not zero, it will progress to step S16.

In step S14, the control system is initialized using the actual slip rotation speed ω _SLPR and the lockup clutch engagement pressure command value _PLUC . The initialization of the control system is performed by a method disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2000-145948 and 2000-145949.

  In step S15, a flag and a timer are initialized. That is, the flag fRE_REC = 0, the timer TMR1 = T1, TMR = T2, and TMR3 = T3.

In step S16, the target slip rotation speed increase adjustment gain G1 is calculated based on the slip rotation speed change rate Δω _SLP with reference to the table of FIG. Further, the target slip rotation speed increase adjustment gain G2 is calculated based on the hysteresis estimation lockup clutch engagement pressure PLUC_HYS with reference to the table of FIG. Calculating a target slip rotation speed increase amount adjusting gain Jideruta _TSLP in accordance with the target slip rotational speed increase amount adjusting gain G1 and G2 and Based on the following equation (9).

In step S17, it calculates a target slip rotation speed increase amount DSLPT based on the target slip rotation speed omega _SLPT and the target slip rotational speed increase amount adjusting gain Jideruta _TSLP following equation (10).

In step S18, the target slip rotation speed ω ′ _SLPT for releasing the lock-up clutch tension is set according to the following equation (11).

In step S19, the target slip rotation speed command value ω _SLPT used in the slip control of FIG. 2 is calculated. The target slip rotation speed command value ω _SLPT is calculated according to the control shown in the flowchart of FIG.

That is, the target slip rotation speed command value ω _SLPT is calculated by the target slip rotation speed calculation unit 100 shown in FIG. 2, and this value is set as the candidate value ω _SLPTA (FIG. 9; S50), and the flag fRE_REC is 0. If so, the candidate value ω _SLPTA is set as the target slip rotation speed command value ω _SLPT (FIG. 9; S51, S52). If the flag fRE_REC is 1, the target slip rotation speed ω ′ _SLPT calculated in step S19 is set as the target slip rotation speed. The command value ω _SLPT is set (FIG. 9; S51, S53).

  The operation of this embodiment will be described with reference to the timing charts of FIGS.

  First, a conventional example will be described with reference to FIG. FIG. 10 is a timing chart in the case of conventional slip control. (A) is throttle opening, (b) is target slip rotational speed, (c) is actual slip rotational speed, (d) is F / F compensator output, (e) is F / B compensator output, (f ) Indicates the engine torque, and (g) indicates the lockup capacity.

At time t1, the actual slip rotation speed ω _SLPR drops to zero as the throttle opening decreases. That is, the lock-up clutch 2 is stuck and is in an engaged state. At this time, the output of the F / B compensator increases as the deviation between the target slip rotational speed ω _SLPT and the actual slip rotational speed ω _SLPR increases and the engagement capacity of the lockup clutch 2 decreases, but the degree of decrease is small, Due to the hysteresis of the actual engagement force of the lock-up clutch 2, it takes time until the converter torque necessary to maintain the slip state is generated.

At time t2, the actual slip rotation speed ω _SLPR finally reaches the target slip rotation speed ω _SLPT and a slip rotation speed capable of slip control is generated. In this way, when the lock-up clutch 2 is continuously engaged, a booming noise is generated, giving the driver a sense of discomfort.

  Next, the present embodiment will be described with reference to FIG. FIG. 11 is a timing chart in the case where the stick-up of the lockup clutch is released by increasing the target slip rotation speed stepwise. (A) is throttle opening, (b) is target slip rotational speed, (c) is actual slip rotational speed, (d) is F / F compensator output, (e) is F / B compensator output, (f ) Indicates the engine torque, and (g) indicates the lockup capacity.

At time t1, the lockup capacity starts to decrease as the throttle opening decreases, but the actual slip rotation speed ω _SLPR starts to decrease due to a response delay in the actual lockup clutch engagement force.

At time t2, the actual slip rotation speed ω _SLPR falls below the predetermined value SLP1, and at time t3 when this state has elapsed for a predetermined time T1, the target slip rotation speed ω _SLPT is increased _stepwise by the target slip rotation speed increase amount DSLPT. . As a result, the lockup capacity decreases stepwise and the actual slip rotation speed ω _SLPR starts to increase.

At time t4, when the actual slip rotation speed ω _SLPR exceeds the predetermined value SLP2, the control system is initialized, so the target slip rotation speed ω _SLPT decreases to the actual slip rotation speed ω _SLPR at this time. Thereafter, normal slip control is resumed.

As described above, in the present embodiment, when the slip rotation speed ω _SLPR is smaller than the predetermined value SLP1 during the slip control and the predetermined time T1 has elapsed, it is determined that the lockup clutch 2 is unintentionally engaged and the lock is applied. Since the fastening force of the up clutch 2 is reduced in a step shape, the fastening state of the lock up clutch 2 can be quickly returned to the slip state. Further, even if there is a hysteresis characteristic with respect to the fastening force of the lockup clutch 2, it is possible to quickly shift to a region where the fastening force can be controlled linearly. Furthermore, since the slip rotation speed ω _SLPR is waited for the predetermined time T1 in a state where the slip rotational speed ω _SLPR is smaller than the predetermined value SLP1, it is possible to more reliably determine whether the lockup clutch is stuck.

In addition, when it is determined that the lockup clutch 2 is unintentionally engaged during slip control, the target slip rotation speed ω _SLPT is increased stepwise, so that the effects of both the feedforward compensator and the feedback compensator are achieved. Thus, the fastening force of the lock-up clutch 2 can be weakened at once.

Further, when increasing the target slip rotational speed omega _SLPT stepwise, since raising only the target slip rotation speed omega _SLPT at elevated point, the target slip rotational speed omega _SLPT in a state where the slip rotational speed omega _SLPR does not occur By increasing the target slip rotation speed ω _SLPT at that time, the target slip rotation speed can be generated, and the fastening force of the lockup clutch 2 can be prevented from being lowered more than necessary.

Further, when the target slip rotation speed ω _SLPT is increased _stepwise , the target slip rotation speed increase adjustment gain G1 that is set larger as the slip rotation speed change rate Δω _SLP is larger than the target slip rotation speed ω _SLPT at the time of increase. As the slip rotational speed ω _SLPR falls more drastically, the fastening force of the lockup clutch 2 can be reduced more greatly and the fastening force can be adjusted without excess or deficiency.

Further, when the target slip rotation speed ω _SLPT is increased _stepwise , a value obtained by multiplying the target slip rotation speed ω _SLPT at the time of increase by the target slip rotation speed increase adjustment gain G1 that is set to be larger as the slip rotation speed change rate is larger. Further, a value obtained by multiplying the target slip rotation speed increase adjustment gain G2 set according to the engagement pressure of the lockup clutch 2 in consideration of the hysteresis characteristic of the lockup clutch 2 is set. Thereby, even if hysteresis exists in the region where the lockup clutch 2 is unintentionally engaged, the engagement force of the lockup clutch 2 can be reduced according to the magnitude of the hysteresis, and the engagement force is excessive or insufficient. Can be adjusted without.

Further, after the target slip rotation speed ω _SLPT is increased stepwise, when the slip rotation speed ω _SLPR exceeds the predetermined value, the target slip rotation speed ω _SLPT is recalculated and set to the actual slip rotation speed ω _SLPR at this point. Therefore, when it can be determined that slip control is possible, it is possible to quickly shift to slip control.

Further, if the slip rotational speed ω _SLPR does not exceed the predetermined value SLP2 even after the predetermined time T3 has elapsed since the target slip rotational speed ω _SLPT is increased in steps, the target slip rotational speed ω _SLPT is _set to the actual slip at this time. since setting the rotational speed omega _SLPR, to initialize the control system when it can not obtain a slip controllable slip speed omega _SLPR, when subsequently not be obtained slip controllable slip speed omega _SLPR again The target slip rotation speed ω _SLPT can be increased stepwise.

(Second Embodiment)
In this embodiment, the system configuration and normal slip control are the same as those in the first embodiment, and the control when the lockup clutch 2 is stuck during slip control is different. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  Hereinafter, the control when the lockup clutch 2 is stuck during the slip control will be described with reference to FIG.

  Steps S1 to S15 are the same as those in the first embodiment. If it is determined in step S13 that the timer TMR3 is not zero, the process proceeds to step S21.

  In step S21, it is determined whether or not the lockup clutch sticking release request flag fRE_REC at the time of the previous process is zero. If it is 0, it will progress to step S22, and if it is not 0, it will progress to step S26.

In step S22, the slip rotation speed gain g _SLP is calculated based on the rotation speed ω _TR of the turbine runner 13 with reference to the table of FIG. Further, based on the slip rotation speed gain g _SLP and the target slip rotation speed ω _SLPT , a converter torque TCNV_TSLP corresponding to the target slip rotation speed is calculated according to the following equation (12).

In step S23, based on the lockup capacity t _{LU —} z at the time of the previous processing and the converter torque TCNV_TSLP corresponding to the target slip rotation speed, the lockup capacity command value t _LU ′ for releasing the lockup clutch sticking according to the following equation (13): Is calculated.

In step S24, the lockup clutch engagement pressure command value _PLUC 'is calculated based on the lockup capacity command value _tLU ' with reference to the table of FIG.

In step S25, a lockup duty S _DUTY 'is calculated such that the engagement pressure of the lockup clutch 2 becomes the lockup clutch engagement pressure command value PLUC'. The relationship between the lockup clutch engagement pressure command value PLUC ′ and the lockup duty S _DUTY ′ is obtained in advance by experiments or the like.

  On the other hand, if it is determined in step S21 that the lockup clutch sticking release request flag fRE_REC at the time of the previous process is not 0, the process proceeds to step S26 and the timer TMR2 (third predetermined time) is counted down.

  In step S27, it is determined whether or not the timer TMR2 is zero, that is, whether or not a predetermined time T2 has elapsed since the start of the tension release processing of the lockup clutch 2. If it is zero, it will progress to step S29, and if it is not zero, it will progress to step S28. Here, the predetermined time T2, which is the initial value of the timer TMR2, is preferably set to a value larger than the response delay or advance of the actual lockup clutch engagement force.

In step S28, the slip rotation command value calculation unit (feedback compensator) 104 in FIG. 2 is stopped and the lockup capacity tLU ′ is held at the value at the previous processing. For example, the lockup duty of the lockup clutch can be held by holding the lockup duty S _DUTY ′ calculated in step S25 at the value at the time of the previous process.

  In step S29, it is determined whether or not the timer TMR2 at the previous processing was zero. If it is zero, the process proceeds to step S31, and if it is zero for the first time this time, the process proceeds to step S30.

  In step S30, the control system is initialized to resume the slip control from the state where the lockup capacity is maintained. The initialization of the control system is performed by a method disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2000-145948 and 2000-145949.

In step S31, the lockup duty S _DUTY used in the slip control of FIG. 2 is calculated. The lockup duty S _DUTY will be described with reference to the flowchart of FIG.

The lock-up duty S _DUTY is calculated by the solenoid drive signal calculation unit 110 in FIG. 2. This value is set as the candidate value S _DUTYA (FIG. 13; S60). If the flag fRE_REC is 0, the candidate value S _{DUTYA is calculated.} was a lockup duty S _dUTY (Figure 13; S61, S62), the flag fRE_REC to the lockup duty S _dUTY 'lockup duty S _dUTY computed in step S25 if 1 (FIG. 13; S61, S63 ).

  Next, the present embodiment will be described with reference to FIG. FIG. 14 is a timing chart when the lock-up clutch is released from sticking by increasing the lock-up clutch engagement force stepwise. (A) is throttle opening, (b) is target slip rotational speed, (c) is actual slip rotational speed, (d) is F / F compensator output, (e) is F / B compensator output, (f ) Indicates the engine torque, and (g) indicates the lockup capacity.

At time t1, the lockup capacity starts to decrease as the throttle opening decreases, but the actual slip rotation speed ω _SLPR starts to decrease due to a response delay in the actual lockup clutch engagement force.

At time t2, the actual slip rotation speed ω _SLPR falls below the predetermined value SLP1, and at time t3 when this state has elapsed for a predetermined time T1, the lockup capacity is reduced stepwise by the converter torque TCNV_TSLP corresponding to the target slip rotation speed, While holding this value, the F / B compensator is stopped.

At the time t4 when the predetermined time T2 has elapsed from the time t3, the actual slip rotation speed ω _SLPR does not exceed the predetermined value SLP2, so that the target slip rotation speed ω _SLPT becomes the actual slip rotation speed ω at this time by initializing the control system. Set to _SLPR .

After that, the actual slip rotational speed ω _SLPR does not exceed the predetermined value SLP2, and the control system is initialized again at time t5 when the predetermined time T3 has elapsed since the lockup capacity was reduced stepwise. As a result, the lockup capacity further decreases, and the actual slip rotation speed ω _SLPR starts to increase.

As described above, in this embodiment, when it is determined that the lock-up clutch 2 is unintentionally engaged during slip control, the lock-up capacity t _LU ′ is reduced in a stepped manner, so that the lock-up clutch 2 is engaged. The force decreases at a stretch and can quickly shift to slip control.

Further, since the amount of decrease in the lockup capacity t _LU ′ that is decreased in a stepwise manner is the converter torque TCNV_TSLP calculated based on the target slip rotation speed, the torque transmitted from the lockup clutch 2 in the engaged state is obtained. By subtracting the converter torque TCNV_TSLP, only the target lockup capacity t _LU ′ can be transmitted by the lockup clutch 2, and it is possible to prevent the fastening force of the lockup clutch 2 from being lowered more than necessary.

Further, since the command value of the lock-up capacity t _LU ′ is held constant for a predetermined time T2 after the command value of the lock-up capacity t _LU ′ is lowered stepwise, the actual lock-up capacity t _{Even if LU} 'has a response delay, it can be reliably reduced.

Further, when the slip rotation speed ω _SLPR exceeds the predetermined value SLP3 after the command value of the lockup capacity t _LU ′ is decreased in a stepped manner, the command value of the lockup engagement capacity t _LU ′ is recalculated and the current value at this time is reduced. Since the lockup engagement capacity t _LU ′ is set, when it can be determined that the slip control is possible, it is possible to quickly shift to the slip control.

Further, if the slip rotational speed ω _SLPR does not exceed the predetermined value SLP3 even after the predetermined time T3 has elapsed since the command value of the lockup capacity t _LU ′ is lowered in a stepped manner, the command value of the lockup fastening capacity t _LU ′ _Is set to the lock-up engagement capacity t _LU ′ at this point in time, so when the slip rotation speed ω _SLPR capable of slip control cannot be obtained, the control system is initialized, and the slip that can be slip controlled thereafter When the rotational speed ω _SLPR cannot be obtained, the command value of the lockup capacity t _LU ′ can be lowered again stepwise.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

It is a schematic block diagram which shows the slip control apparatus of the torque converter in this embodiment. It is a block diagram which shows the slip control in this embodiment. It is a flowchart which shows control of the slip control apparatus of the torque converter in 1st Embodiment. It is a table which shows the relationship between a turbine runner and a slip rotational speed gain. It is a table which shows the relationship between an engine speed and an engine torque. It is a table which shows the relationship between lockup clutch fastening pressure and lockup capacity. It is a table which shows the relationship between slip rotational speed change amount and target slip rotational speed increase amount adjustment gain. It is a table which shows the relationship between the lockup clutch fastening pressure for hysteresis estimation, and target slip rotational speed increase amount adjustment gain. ₆ is a flowchart illustrating a method for calculating a target slip rotation speed command value ω _SLPT used in slip control. It is a timing chart in the case of the conventional slip control. It is a timing chart in the case of releasing stickiness of a lockup clutch by raising a target slip rotation speed in steps. It is a flowchart which shows control of the slip control apparatus of the torque converter in 2nd Embodiment. It is the flowchart explaining the method of calculating lockup duty S _DUTY used by slip control. It is a timing chart in the case of releasing stickiness of a lockup clutch by increasing lockup clutch fastening force in steps.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Lockup clutch 3 Lockup control valve 3a Spring 4 Lockup solenoid 5 Controller 6 Power supply voltage sensor 7 Pump impeller rotation sensor 8 Turbine runner rotation sensor 9 Transmission output shaft rotation sensor 10 Throttle rotation sensor 11 ATF temperature sensor 12 Pump impeller 13 Turbine runner 14 Engine 15 Transmission 16 Drive wheel 100 Target slip rotation speed calculation unit 101 Actual slip rotation speed calculation unit 102A Pre-compensator 102B Pre-compensator 103 Slip rotation speed deviation calculation unit 104 Slip rotation speed command value Calculation unit 105 Slip rotation speed gain calculation unit 106 Target converter torque calculation unit 107 Engine output torque estimation unit 108 Target lockup capacity calculation unit 109 Lockup clutch engagement pressure command value calculation Calculation unit 110 Solenoid drive signal calculation unit

Claims (13)

In a slip control device for a torque converter having a lock-up clutch that can fasten an input element and an output element, which transmits a driving force of an engine to a driving force system of a vehicle via a fluid.
Slip rotational speed calculating means for calculating a slip rotational speed which is a rotational speed difference between the input element and the output element;
Target slip rotation speed calculating means for calculating a target slip rotation speed which is a target value of the slip rotation speed based on the driving state of the vehicle;
Slip control means for controlling the fastening force of the lock-up clutch so that the slip rotation speed matches the target slip rotation speed;
Engagement force control for controlling the engagement force of the lockup clutch to decrease stepwise when the slip rotation speed falls below a first predetermined value smaller than the target slip rotation speed during execution of the slip control means. Means,
A slip control device for a torque converter, comprising:   When the slip rotation speed is smaller than the first predetermined value and the first predetermined time elapses during execution of the slip control means, the engagement force control means steps the engagement force of the lockup clutch. The slip control device for a torque converter according to claim 1, wherein the slip control device is controlled so as to be lowered.   The said fastening force control means controls so that the fastening force of the said lockup clutch may be reduced in a step shape by raising the said target slip rotational speed in a step shape. Slip control device for torque converter.   4. The slip control device for a torque converter according to claim 3, wherein when the target slip rotation speed is increased stepwise, the fastening force control means increases the target slip rotation speed at the time of increase.   5. The slip control of a torque converter according to claim 4, wherein when the target slip rotation speed is increased stepwise, the fastening force control means increases the higher the higher the rate of change of the slip rotation speed. apparatus.   6. The slip control of a torque converter according to claim 4, wherein the fastening force control means increases the target slip rotation speed stepwise based on a hysteresis characteristic of the lockup clutch. apparatus.   When the target slip rotation speed is increased stepwise by the fastening force control means and the slip rotation speed exceeds a second predetermined value greater than the first predetermined value, the fastening force control means causes the target slip 7. The torque converter according to claim 3, wherein the torque control is stopped after increasing the rotation speed, and the slip control is restarted after recalculating the target slip rotation speed. Slip control device.   If the slip rotation speed does not exceed the second predetermined value even after a second predetermined time has elapsed after controlling the target slip rotation speed to increase stepwise by the fastening force control means, the fastening The slip of the torque converter according to claim 7, wherein the target slip rotation speed is stopped by the force control means, and the slip control is restarted after recalculating the target slip rotation speed. Control device. Lockup capacity command value calculating means for calculating a command value of a lockup capacity that is a torque transmitted by the lockup clutch based on the torque of the engine and the target slip rotation speed;
3. The control according to claim 1, wherein the engagement force control unit controls the engagement force of the lockup clutch to be decreased stepwise by decreasing the command value of the lockup capacity in a stepwise manner. The slip control apparatus of the torque converter as described. Converter torque calculating means for calculating a converter torque that is a transmission torque of the fluid based on the target slip rotation speed;
The slip control device for a torque converter according to claim 9, wherein the amount of decrease in which the lockup capacity command value is decreased stepwise is the converter torque.   The fastening force control means holds the lockup capacity command value constant for a third predetermined time after controlling the lockup capacity command value to decrease stepwise. Or the torque converter slip control device according to 10.   When the slip rotation speed exceeds a third predetermined value after the lockup capacity command value is lowered stepwise by the fastening force control means, the lockup capacity command value is lowered by the fastening force control means. The slip control device for a torque converter according to any one of claims 9 to 11, wherein the slip control is restarted after stopping the operation and recalculating the lockup capacity command value.   When the slip rotation speed does not exceed the third predetermined value after the fourth predetermined time has elapsed after controlling the engagement force of the lockup clutch to be lowered stepwise by the engagement force control means, 13. The slip control is resumed after stopping the lowering of the lockup capacity command value by the fastening force control means and recalculating the lockup capacity command value. Slip control device for torque converter.

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