JP4613493B2 - Slip control device for torque converter - Google Patents

Description

  The present invention relates to an improvement in a slip control device for a torque converter having a lock-up clutch.

  Conventionally, a torque converter lock-up control device interposed in a power transmission system of an automatic transmission including a continuously variable transmission has been designed to increase torque in order to reduce deterioration in fuel consumption due to slippage of the torque converter. In an operation area that does not require a speed change shock absorption function, it has a lockup mode in which the input / output elements of the torque converter are directly connected. There are known three modes including a converter mode to be performed and a slip mode in which a lock-up clutch is semi-engaged and a predetermined slip state is maintained, and the three modes are appropriately switched depending on the operation state. Yes.

Then, a basic target slip rotation is set based on the driving state of the vehicle, and an output obtained by inputting the basic target slip rotation to a predetermined reference model (first-order lag filter) and the reference model is set as the target slip rotation. In addition, it is known that the slip control (F / F compensation + F / B compensation) is performed so that the actual slip rotation speed (engine rotation speed−primary rotation speed (input shaft rotation speed)) follows the target slip rotation speed. (For example, patent document 1).
JP-A-11-141777

  By the way, in the above conventional example, the change speed (change amount) of the primary rotational speed (turbine rotational speed) from the start to the end of the slip control is such that the vehicle speed increases as shown in FIG. Get smaller.

However, in the above prior art, when setting the target slip rotation speed, the change speed of the primary rotation speed is not considered, so the change speed of the target slip rotation speed with respect to the change speed of the primary rotation speed (reference model response characteristics) May become excessive and the engine speed may drop rapidly. In particular, if the change rate of the target slip rotation speed is excessive in the region where the change speed of the primary rotation speed is small, the actual slip rotation speed is also small, so the lockup clutch is suddenly engaged, and the driver feels uncomfortable due to the shock. Therefore, the present invention provides a degree of freedom in the amount of change in the engine speed at the time of lock-up or slip lock-up, and performs smooth control by preventing sudden engagement and rapid changes in the engine speed. For the purpose.

The present invention obtains a target slip rotation speed of the lockup clutch from the driving state of the vehicle, and calculates an output for controlling the engagement state of the lockup clutch by feedback control based on the target slip rotation and the actual slip rotation speed. Feedback compensation means, feedforward compensation means for calculating an output for controlling the engagement state of the lockup clutch by feedforward control based on the target slip rotation, command values of these feedback compensation means, and feedforward compensation means When controlling the engagement state of the lock-up clutch based on the command value, the target slip rotation speed is set so that the decrease speed increases as the increase speed of the turbine rotation speed (input shaft rotation speed or primary rotation speed) increases. .

  Therefore, according to the present invention, the change speed (change amount) of the pump impeller rotation speed can be arbitrarily set, and the setting range of the change speed (change amount) of the engine rotation speed can be expanded. Thus, it is possible to prevent sudden engagement of the lock-up clutch and judder and to provide an automatic transmission excellent in drivability.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the system configuration of the present invention.

  In FIG. 1, reference numeral 1 denotes a torque converter interposed in a power transmission system such as an automatic transmission including a continuously variable transmission, and transmits power between input / output elements via an internal working fluid. .

  The torque converter 1 further includes a lockup clutch 2 that rotates together with the torque converter output element (turbine). The lockup clutch 2 inputs and outputs the torque converter 1 when fastened to the torque converter input element (impeller). A lockup state in which elements are directly connected is assumed.

  The lock-up clutch 2 responds to a differential pressure PA-PR between the torque converter apply pressure PA and the torque converter release pressure PR on both sides (front and rear), and when the release pressure PR is higher than the apply pressure PA, the lock-up clutch 2 When the release pressure PR is lower than the apply pressure PA without being directly connected between the torque converter input / output elements, the lockup clutch 2 is engaged and directly connected between the torque converter input / output elements.

  When the latter is engaged, the engagement force of the lockup clutch 2, that is, the lockup capacity, is determined by the differential pressure PA-PR, and the engagement force of the lockup clutch 2 increases as the differential pressure increases. Increase lockup capacity.

  The differential pressure PA-PR is controlled by a well-known lockup control valve 3, and the apply pressure PA and the release pressure PR are caused to act on the lockup control valve 3 so as to oppose each other. The urging force of the spring 3a is applied in the direction, the spring force is applied in the same direction as the release pressure PR, and the signal pressure Ps is applied in the same direction as the release pressure PR.

  The lockup control valve 3 determines the differential pressure PA-PR so that the hydraulic pressure and the biasing force of the spring are balanced.

  Here, the signal pressure Ps applied to the lock-up control valve 3 is generated by the lock-up solenoid 4 according to the lock-up duty using the pump pressure PP as an original pressure. 4 to control the differential pressure PA-PR.

  The controller 5 includes a signal indicating the running state of the vehicle and the driving situation of the driver, for example, a signal from the output shaft rotation sensor 9 provided in the automatic transmission, a turbine runner rotation speed (from the turbine rotation sensor 8 of the torque converter 1). A signal indicating an input shaft rotation speed or a primary rotation speed), a signal indicating a pump impeller rotation speed from an impeller rotation sensor 7 for detecting an input rotation speed (= engine rotation speed Ne) to the torque converter 1, a throttle opening sensor 10 The signal (throttle opening TVO or accelerator operation amount), the signal from the oil temperature sensor 11 and the like are input, and the control of the lockup clutch 2 such as engagement, disengagement or slip is performed by these detection signals. The vehicle speed VSP is obtained by multiplying the output shaft rotation speed detected by the output shaft rotation sensor 9 by a predetermined constant.

  The controller 5 performs slip lockup by switching between open loop control and slip control (feedforward control + feedback control). The controller 5 determines a lockup duty for driving the lockup solenoid 4 and supplies the power supply voltage signal 6 to the power supply voltage signal 6. The lockup duty is corrected accordingly.

  Next, slip control among the controls performed by the controller 5 will be described based on the control system configuration diagram of FIG.

The target slip rotation calculation unit S100, based on the vehicle speed v and the throttle opening TVO (or accelerator operation amount) and the oil temperature T _ATF, etc., the target slip rotation at the least occurrence of torque fluctuation and muffled sound (speed) omega _SLPT To decide.

The actual slip rotation calculation unit S103 calculates the actual slip rotation (speed) ω _SLPR of the torque converter 1 by subtracting the rotation speed ω _TR of the turbine runner from the rotation speed ω _iR of the pump impeller.

  Here, the rotational speed of the impeller is equivalent to the engine rotational speed Ne, and the turbine rotational speed is equivalent to the input shaft rotational speed.

In the precompensators (S101A and S101B), the target slip rotation correction value is calculated by passing the target slip rotation ω _SLPT through a compensation filter set so as to have a response intended by the designer.

First, the predistorter S101A, based on the target slip rotational omega _SLPT, the first target slip rotation correction value omega _SLPTC1 is calculated by the following equation.

However, G _R (S) is a reference model, and a transfer function is set so as to obtain a target response intended by the designer.

Next, in the pre-compensator S101B, the second target slip rotation correction value ω _SLPTC2 is

Calculate from However,

G _M (s) is a feedforward compensator, and P (s) is a transfer function that models the slip rotation part to be controlled.

The dead time processing unit S111 performs processing related to the ^dead time e ^−Ls possessed by the lockup mechanism.

The slip rotation speed deviation calculation unit S102 calculates a slip rotation deviation ω _SLPER between the value obtained by performing the _dead time processing on the first target slip rotation correction value ω _SLPTC1 and the actual slip rotation speed ω _SLPR .

In slip rotation command value calculating section S104, in order to suppress the slip rotational deviation omega _SLPER, proportional-integral control (hereinafter, PI control) by feedback compensator constituted by (S104), first slip rotation command value omega _SLPC1 The

However, K _p: proportional control constant K _I: integral control constant s: calculated from differential operator.

Then, by _adding the first slip rotation command value ω _SLPC1 and the second target slip rotation correction value ω _SLPTC2 as shown in the following equation, the slip rotation command value ω _{SLPC serving} as a control input is calculated.

In the slip rotation gain calculation unit S106, the slip rotation gain g _SLPC corresponding to the current turbine rotation speed ω _TR is retrieved from the map shown in FIG.

In the target converter torque calculation unit S105, the target converter torque t _CNVC for achieving the slip rotation command value ω _SLPC at the turbine rotation speed ω _TR

Calculate from

The engine torque estimator S108 retrieves an engine torque map value t _ES from the engine speed Ne and the throttle opening TVO (or the accelerator operation amount) using a preset engine overall performance map, and stores the engine torque map value t _ES in this. The estimated engine torque t _EH is passed through a filter when the characteristic (the amount of transport delay in the intake system) is the first-order delay of the time constant T _ED

Calculate from

The target lockup clutch tightening capacity computing unit S107, the target lockup clutch tightening capacity t _LU by subtracting the target converter torque t _CNVC from the engine torque estimated value t _EH is calculated by the following equation.

In the lockup clutch engagement pressure command value calculation unit S109, the lockup clutch engagement pressure command value (lockup in the figure) for achieving the current target lockup clutch engagement capacity _tLU from the lockup clutch capacity map shown in FIG. Clutch engagement pressure) P _LUC is searched.

The solenoid drive signal calculation unit S110 determines a lockup duty S _DUTY for setting the actual lockup clutch engagement pressure to the lockup clutch engagement pressure command value (differential pressure command value) _PLUC .

  Next, the outline of the slip control performed by the controller 5 will be described with reference to the timing charts of FIGS.

  In the present invention, the period from the start to the end of the slip control is divided into three regions (region 1 → (region 3) → region 2), and the control logic for setting the target slip rotation speed Tslip is individually provided for each region. Do.

First, in region 1, slip control is performed based on the target slip rotation speed Tslip according to the change speed of the primary rotation speed InpREV (= input shaft rotation speed = turbine rotation speed), and the slip rotation speed SlpREV (= actual slip rotation speed ω). _{When the SLPR and the} like are decreased and fall below a predetermined rotational speed (SlpREV_ED), the control shifts to a region 2 for the purpose of smoothly ending the slip control. In this region 2, smoothing control (first-order lag control) is performed so that the actual slip rotation speed at the time of region switching becomes the final target value TGT_SREV smoothly.

  Further, when the shift is started before the slip rotation speed decreases and falls below the predetermined rotation SlpREV_ED (before shifting to the area 2) during the control of the area 1, the primary rotation speed inpREV does not change with the throttle opening being constant. If the area is entered, the process proceeds to area 3.

In this region 3, since the primary rotational speed inpREV hardly changes, slip control is performed based on the target slip rotational speed Tslip that decreases by a predetermined amount (engine rotational speed change amount) TGT_EREV, and the slip rotational speed ω _SLPR changes the predetermined rotational speed SlpREV_ED. If it falls below, it shifts to region 2.

  In the following description, a case where the predetermined control cycle is 20 msec is shown.

<Region 1>
FIG. 5 shows the state of region 1 at the start of slip control, where the primary rotational speed inpREV is increasing and the engine rotational speed EngREV> primary rotational speed (greater than InpREV_ED).

First, at time t0 which is the slip control start time, the primary rotational speed inpREV is stored as the primary rotational speed InpREV_ST at the start of slip control, and the difference between the engine rotational speed and the primary rotational speed (actual slip rotational speed ω _SLPR ) is started. Stored as slip rotation speed SlpREV_ST.

  Since the slip rotation speed SlpREV_ST at the start of control is larger than the target switching slip rotation speed SlpREV_ED and the primary rotation speed inpREV is smaller than the target switching primary rotation speed InpREV_ED, based on the target slip rotation speed Tslip according to the changing speed of the primary rotation speed inpREV Perform slip control.

  Next, at time t1 when the primary rotational speed inpREV increases, the target slip rotational speed (Tslip) is determined according to the amount of change ΔInpREV in the primary rotational speed. At that time, restrictions are provided as described later (see FIG. 11).

  At this time, if the target slip rotation speed SlpREV falls below a predetermined limit value SREV_LMSR (first limit value) and the primary rotation speed inpREV exceeds a predetermined limit value PREV_LMSR (second limit value), early lockup is performed. Restrictions for prevention and judder avoidance are applied as described below.

  When the target slip rotational speed SlpREV falls below the target switching slip rotational speed SlpREV_ED, or at the time t2 when the primary rotational speed inpREV exceeds the target switching primary rotational speed inpREV_ED, the method for generating the target slip rotational speed is changed from the processing in the region 1 to the region Switch to process 2.

The target slip rotation speed (Tslip) calculated at times t0 to t2 is input to the reference model G _R (S) (for example, first-order lag characteristic) to generate a slip rotation speed command value Tslip_ref.

At this time, the time constant of the reference model G _R (S) is set so as to have a fast response characteristic. Note that, at times t0 to t2 in the figure, the target slip rotation speed SlpREV and the slip rotation speed command value Tslip_ref are separated for the sake of explanation, but are actually on the same line (the same applies hereinafter).

<Region 2>
FIG. 6 shows the state of region 2 for the target slip rotation speed SlpREV to decrease and fall below a predetermined rotation speed (SlpREV_ED) to smoothly finish the slip control.

  At time t2, in the state where the control is switched from the region 1 or the region 3 at the start of the control to the control of the region 2, the state of the target slip rotation speed Tslip = target switching slip rotation speed SlpREV_ED or the primary rotation speed inpREV = target switching primary rotation Since the state is InpREV_ED, the control shifts to the region 2.

  In this area 2, the target slip rotation speed is switched to the final value (TGT_SREV) and input to the reference model to generate a slip rotation speed command value. The final value (TGT_SREV) is set to TGT_SREV = 0 rpm when locking up, and is set to a value corresponding to the throttle opening TVO when driving slips.

<Region 3>
FIG. 7 shows a state where the primary rotational speed inpREV is substantially constant (InpREV> InpREV_ED after the start of shifting) and the engine rotational speed EngREV> InpREV at the start of slip control.

At time t0 which is the slip control start time, the primary rotation speed inpREV is stored as the primary rotation InpREV_ST at the start of slip control, and the difference (ω _SLPR ) between the engine rotation speed EngREV and the primary rotation speed inpREV is set as the slip rotation speed SlpREV_ST at the start of control. Remember.

  In this case, since the primary rotational speed inpREV is higher than the target switching primary rotational speed InpREV_ED, the processing in the region 3 is performed.

  At time tl, the target slip rotation speed Tslip is set according to the set engine rotation speed change amount TGT_EREV, and is corrected by the primary rotation speed change amount ΔInpREV20 in one control cycle. At that time, restrictions are added as described later (see FIG. 13).

  At this time, if the target slip rotational speed SlpREV falls below the predetermined limit value SREV_LMSR and the primary rotational speed inpREV exceeds the predetermined limit value PREV_LMSR, restrictions for preventing early lockup and avoiding judder are applied as described later. . The engine speed change amount TGT_EREV is the difference between the engine speed EngREV in the previous control cycle and the current value. Similarly, the primary speed change amount ΔInpREV20 is also the difference between the previous control cycle value and the current value. is there.

  At time t2, when the target slip rotation speed SlpREV falls below the target switching slip rotation speed SlpREV_ED), the method for generating the target slip rotation speed is switched from the process in the area 3 to the process in the area 2.

  The target slip rotation speed Tslip calculated at times t0 to t2 is input to a reference model (for example, a first-order lag characteristic) to generate a slip rotation speed command value Tslip_ref. At this time, the time constant of the reference model is set so as to have a fast response characteristic.

<Details of control>
Next, details of the control shown in FIGS. 5 to 7 will be described below with reference to a flowchart of processing performed by the controller 5.

  FIGS. 8 to 10 show processing for determining the above-mentioned areas 1 to 3 of the slip control, and FIGS. 11 to 13 show the control of each area. These flowcharts show a predetermined cycle (for example, 20 msec). It is executed every time.

  First, in S10 of FIG. 8, it is determined whether or not it is the start time of slip control by feedback control (+ feedforward control).

  This determination is made based on the value of the flag fFBCALC indicating the control state. If the flag fFBCALC = 0, it is determined that the open loop control is in progress, and the process ends. If the flag fFBCALC = 1, the process proceeds to feedback control. Since it is doing, it progresses to Sll. The flag fFBCALC is set according to the driving state such as the actual slip rotation speed and the vehicle speed by a process not shown.

In S11, as shown in FIGS. 5 and 7, the primary rotational speed inpREV is stored as the primary rotational speed InpREV_ST at the start of slip control, and the difference between the engine rotational speed and the primary rotational speed (actual slip rotational speed ω _SLPR ) is stored. Stored as the slip rotation speed SlpREV_ST at the start of control.

  In S12, the slip control region is determined according to the current primary rotational speed inpREV.

  That is, if primary rotational speed InpREV <target switching primary rotational speed InpREV_ED, the process proceeds to S13 to perform a determination process mainly based on region 1, and if InpREV ≧ InpREV_ED, since region 3 or region 2, the process proceeds to S14.

  In S13, 0 indicates the determination process for the area 1 shown in FIG. 9, and S14 indicates the determination process for the area 2 or 3 shown in FIG.

  Next, the determination process for region 1 in FIG. 9 will be described.

  In S20, it is determined whether or not the region 2 is based on the target slip rotation speed Tslip. If Tslip ≦ predetermined rotational speed SlpREV_ED, the region 2 is determined and the process proceeds to S23. If Tslip> SlpREV_ED, the process proceeds to S21 to further determine the region. In S23, the process of area 2 is performed in FIG.

  In S21, the primary rotational speed inpREV is compared with the target switching primary rotational speed InpREV_ED. If inpREV ≧ InpREV_ED, it is determined as region 3 and the process proceeds to S24. If inpREV <InpREV_ED, it is determined as region 1 and the process proceeds to S22. move on. In S22, the process for area 1 is performed in FIG. 11 described later, and in S24, the process for area 3 is performed in FIG. 13 described later.

  Next, the determination process for region 3 in FIG. 10 will be described.

  In S30, it is determined whether or not the region 3 is based on the target slip rotation speed Tslip. If Tslip ≦ predetermined rotational speed SlpREV_ED, the region 2 is determined and the process proceeds to S32. On the other hand, if Tslip> SlpREV_ED, the process proceeds to S31.

  In S31, the process of area 3 is performed in FIG. 13 described later, and in S32, the process of area 2 is performed in FIG. 12 described later.

  Next, the processing of region 1 performed in S22 will be described with reference to the flowchart of FIG.

  In S201, it is determined whether or not the primary rotational speed InpREV is increased as compared with the previous control. If the primary rotational speed InpREV is increased, the process proceeds to S202, and if it is constant or decreased, the process proceeds to S209.

  In S202 when increasing, the target slip rotation speed change amount (change speed) dtslp1 due to the change of the primary rotation speed is calculated based on the following equation.

dtslp1 = SlpREV_ED + a. (A / B) −Tslip ₂₀ (9)
here,
a = Tslip ₂₀ -SlpREV
A = InpREV_ED-inpREV_FL
B = InpREV_ED-inpREV_FL ₂₀
It is.

That is, in FIG. 5, when the current time is t1, the target slip rotation speed of the previous control cycle (before ₂₀ msec) is Tslip ₂₀ , and a in the above equation (9) is the current target slip rotation speed SlpREV and the previous value. Difference, that is, the change speed (change amount) of the target slip rotation speed SlpREV.

In FIG. 5, A in the above equation (9) is the difference between the target switching primary rotation InpREV_ED and the current primary rotation speed InpREV_FL at the current time t1, and B is the target switching primary rotation InpREV_ED and the previous time. Since this is the difference in the primary rotational speed InpREV_FL ₂₀ at the time of control (before ₂₀ msec), A / B in the equation (9) indicates the rate of change in the primary rotational speed InpREV. Then, the difference between the predetermined slip rotation speed SlpREV_ED and the previous target slip rotation speed Tslip ₂₀ is multiplied by the rate of this change to obtain the target slip rotation speed change amount dtslp1.

  Thereby, the amount of change (change speed) dtslp1 of the target slip rotation speed SlpREV based on the change speed of the primary rotation speed InpREV is calculated.

  Next, in S203, a target slip rotation speed change amount dtslp2 that is limited by the engine rotation speed gradient is calculated by the following equation.

dtslp2 = max [dtslp1, (TGT_EREV−ΔInpREV ₂₀ )]
……… (10)
Here, TGT_EREV is the difference between the current engine rotation speed (pump impeller rotation speed) EngREV and the engine rotation speed at the previous control, and indicates the change speed (change amount) of the engine rotation speed. ΔInpREV ₂₀ The current time t1 is the difference between the current primary rotational speed InpREV_FL and the primary rotational speed InpREV_FL ₂₀ at the previous control, and indicates the change speed (change amount) of the primary rotational speed.

  Therefore, the above equation (10) calculates the larger one of the change amount dtslp1 of the target slip rotation speed and the difference between the change speed of the engine rotation speed and the change speed of the primary rotation speed as the target slip rotation speed change amount dtslp2. .

  In next step S204, it is determined whether or not the restriction based on the slip rotation speed change amount is applied based on a comparison between the target slip rotation speed Tslip and the slip rotation speed change amount restriction permit slip rotation speed SREV_LMSR. SREV_LMSR is set to a value larger than the target switching slip rotation speed SlpREV_ED (see FIG. 5).

  If Tslip> SREV_LMSR, it is determined that the restriction on the slip rotation speed is not necessary, and the process proceeds to S207. If the target slip rotation speed Tslip is equal to or less than the limit permission slip rotation speed SREV_LMSR, the process proceeds to S205 to make the next determination.

  In S205, as in S204, it is determined based on a comparison between the primary rotation speed InpREV and the slip rotation speed change amount restriction permission primary rotation speed PREV_LMSR whether or not the restriction is imposed by the slip rotation speed change amount. Note that PREV_LMSR is set to a value smaller than the target switching primary rotation InpREV_ED.

  If InpREV ≦ PREV_LMSR, it is determined that no restriction is required, and the process proceeds to S207. Otherwise, the process proceeds to S206 for adding a restriction.

  In S206, the target slip rotation speed change amount dtslp3 that is limited by the slip rotation speed change amount is calculated by the following equation.

dtslp3 = mid [dtslp2, DSREV_LM_MAX, DSREV_LM_MIN] (11)
However, DSREV_LM_MAX is the upper limit value of the target slip rotation speed, DSREV_LM_MIN is the lower limit value of the target slip rotation speed, and the target slip rotation speed change amount dtslp3 is the target slip rotation speed change amount dtslp2 obtained in S203 and the upper limit value DSREV_LM_MAX. Among the three lower limit values DSREV_LM_MIN, an intermediate one is calculated as a target slip rotation speed change amount dtslp3 with limitation.

  In other words, in S206, if the target slip rotation speed Tslip is lower than a predetermined value (restriction permission slip rotation speed SREV_LMSR) and the primary rotation speed InpREV is higher than a predetermined value (restriction permission slip rotation speed PREVLMSR), the target slip rotation speed changes. The target slip rotation speed change amount dtslp3 for limiting the amount to avoid judder is obtained, and judder and early lockup can be avoided, and slip control is performed smoothly.

  On the other hand, in S207 when the restriction on the slip rotation speed change amount is unnecessary, the value dtslp2 obtained in S203 is set as the target slip rotation speed change amount dtslp3.

  Thus, after setting the target slip rotation speed change amount dtslp3 in S206 or S207, in S208, the target slip rotation speed change amount Δ multiplied by the remaining rotation speed limit up to the final target slip rotation speed TGT_SREV (see FIG. 5). Tslip is calculated by the following equation.

ΔTslip = max [dtslp3, TGT_SREV−Tslip ₂₀ ] (12)
That is, the larger of the difference between the final target slip rotation speed TGT_SREV and the target slip rotation speed Tslip ₂₀ at the previous control and the target slip rotation speed change amount dtslp3 is calculated as the target slip rotation speed change amount ΔTslip. The amount of change is limited so as not to fall below the final target slip rotation speed TGT_SREV.

  On the other hand, in S209 in which the primary rotational speed InpREV is decreased or constant compared to the previous control in the determination of S201, the primary rotational speed InpREV starts to decrease, the target slip rotational speed change amount ΔTslip is set to 0, The target slip rotation speed SlpREV of the cycle is maintained.

Next, in S210, the target slip rotation speed Tslip is calculated by the following equation using the calculated target slip rotation speed change amount ΔTslip and the previous target slip rotation speed (Tslip ₂₀ ) (Tslip ₂₀ ).

Tslip = max [(Tslip ₂₀ + ΔTslip), (ENSTEREV−InpREV)] (13)
The larger of the difference between the previous control value plus the target slip rotational speed change amount ΔTslip and the preset engine avoidance engine rotational speed (ENSTEREV) and the primary rotational speed InpREV is calculated as the target slip rotational speed Tslip. To do.

  That is, the primary rotational speed InpREV is restricted from entering the engine stall determination area by the target slip rotational speed.

  In step S211, the time constant TC of the reference model in the region 1 is set to a small fixed value set in advance to improve the response. Note that after the process of S211, the process returns to S10 of FIG.

8, 9, and 11, the target slip rotation speed Tslip according to the change speed ΔInpREV ₂₀ of the primary rotation speed InpREV is obtained, and the slip control is performed.

That is, the slip rotation command value Tslip_ref (= target value Tslip) is gradually decreased from the slip rotation speed SlpREV_ST at the start of the slip control toward a predetermined slip rotation speed (TGT_SREV). The change amount of the command value Tslip_ref is set according to the change amount ΔInpREV ₂₀ of the primary rotation speed InpREV in the control cycle (for example, ₂₀ msec).

  As a result, the amount of change in engine speed can be set arbitrarily, and the degree of freedom in changing the slip speed can be increased. When slip control is applied in various driving situations, judder avoidance and locking It is possible to easily set a target value that avoids sudden engagement of the up-clutch and a sudden drop in engine speed, and slip control that does not give the driver a sense of incongruity is possible.

Then, the target slip rotation change amount dtslp1 is obtained, and the engine speed is limited (dtslp2). The upper and lower limits are restricted to the target slip rotation speed change result dtslp2 to obtain the target slip rotation speed change amount ΔTslip. The current value Tslip is obtained by adding to the previous slip rotational speed command value Tslip ₂₀ (one control period before).

Here, the target slip rotation speed change amount dtslp1 is obtained by multiplying the difference between the predetermined slip rotation speed (SlpREV_ED) and the previous slip rotation speed command value (Tslip ₂₀ ) by the change rate of the primary rotation speed.

  The predetermined slip rotation speed (SlpREV_ED) is set as the target switching slip rotation speed, and is set to a value higher than the target slip rotation speed (steady slip rotation: TGT_SREV).

  The engine speed limit is arbitrarily set as an upper limit value to prevent a sudden decrease in the engine speed during the lockup operation. Further, the slip rotation speed limit (upper and lower limits) is set to a value for avoiding judder and early fastening.

  As described above, the engine rotation speed change during the slip control can be set within a predetermined range, and judder and early fastening can be prevented to achieve smooth slip lock-up (drive slip) or lock-up.

  Next, the control of the area 2 will be described with reference to FIG.

  First, in S221, the final target slip rotation speed (TGT_SREV) is set according to the operating state. For example, it is set from a fixed value such as TGT_SREV = 0 rpm for lock-up, 50-100 rpm for slip lock-up, or a map of TGT_SREV set in advance according to the throttle opening TVO.

When using a map TSREVTBL corresponding to the throttle opening TVO,
TGT_SREV = TSREVTBL (TVO)
A final target slip rotation speed TGT_SREV is obtained.

  In S222, the slip rotation speed command value Tslip_ref is limited so that the target slip rotation speed does not enter the engine stall determination area at the engine stall avoidance engine rotation speed ENSTEREV. The slip rotation speed command value Tslip_ref is calculated by the following equation.

Tslip_ref = max [TGT_SREV, (ENSTEREV-InpREV)] (14)
In other words, the larger of the difference between the final target slip rotation speed TGT_SREV obtained in S221 and the preset engine stall avoidance engine speed (ENSTEREV) and the primary rotation speed InpREV is calculated as the slip rotation speed command value Tslip_ref. .

  Next, in S223, the time constant TC of the reference model is set. The time constant TC may be calculated, for example, by searching a map TTCTBL of time constants set in advance according to the throttle opening TVO.

  In S224, a first-order lag filter is applied from the slip rotation speed command value Tslip_ref obtained in S222 and the time constant TC in S223 so that the slip control ends smoothly (annealing control). Is obtained as the target slip rotation speed Tslip. Note that after the process of S211, the process returns to S10 of FIG.

  When the slip rotation speed command value or the actual slip rotation reaches the predetermined slip rotation speed (target switching slip rotation speed SlpREV_ED) by the control of S221 to S224 in FIGS. 8 to 10 and 12 above, the slip rotation speed command value is Then, switching is made so as to be determined by the annealing control by the first-order lag filter. As a result, when the slip rotation speed is converged to a predetermined value (steady state), a shock due to a sudden change in the target value, a fastening shock, or the like can be prevented, and the lockup operation can be completed smoothly.

  Then, the target slip rotation speed Tslip is obtained as a target slip rotation speed (final value: TGT_SREV) set according to the operating state, and is subjected to a restriction on the engine stall avoidance engine rotation speed as a slip rotation speed target value Tslip_ref. The target slip rotation speed Tslip is determined using a first-order lag filter with the difference between the slip rotation speed target value and the slip rotation speed command value at the time of switching as an initial value.

  When used in drive slip lockup, the final target slip rotation speed TGT_SREV is set according to the throttle opening TVO, and the time constant TC of the first-order lag filter is set according to the throttle opening TVO. As a result, when the slip rotation speed is converged to a predetermined value (steady state), a shock or fastening shock due to a sudden change in the target value can be prevented, and the lockup operation can be completed smoothly. Since the time constant of the model is set, it is possible to always bring the slip state / lock-up state with the response characteristic suitable for the driving state.

  Next, the processing of region 3 will be described with reference to FIG.

First, in S231, it is determined whether the primary rotational speed InpREV is increasing. That is, as shown in FIG. 5, the primary rotational speed change speed (change amount) ΔInpREV ₂₀ which is the difference between the current primary rotational speed InpREV_FL and the primary rotational speed InpREV_FL ₂₀ at the previous control, and a preset value TSDPREV2 If ΔInpREV ₂₀ is equal to or greater than the predetermined value TSDPREV2, it is determined that the value has increased, and the process proceeds to S232. If not, the process proceeds to S238.

  In S232 when increasing, the target slip rotation speed change amount dtslp1 limited by the engine rotation speed gradient is calculated based on the following equation.

dtslp1 = TGT_EREV−ΔInpREV ₂₀ (16)
However, TGT_EREV indicates the change speed (change amount) of the engine rotation speed shown in FIG. In this case, TGT_EREV is a set value (adapted value), and ΔInpREV ₂₀ is a correction term.

  In S233, it is determined whether or not the restriction based on the slip rotation speed change amount is to be applied based on the comparison between the target slip rotation speed Tslip and the slip rotation speed change amount restriction permit slip rotation speed SREV_LMSR (see FIG. 5). To do.

  If Tslip ≧ SREV_LMSR, it is determined that the limitation on the slip rotation speed is not required, and the process proceeds to S236. If the target slip rotation speed Tslip is less than the limit permission slip rotation speed SREV_LMSR, the process proceeds to S2234 and the next determination is performed.

  In S234, as in S233, whether or not the restriction based on the slip rotation speed change amount is to be applied is based on a comparison between the primary rotation speed InpREV and the slip rotation speed change amount restriction permission primary rotation speed PREV_LMSR (see FIG. 5). Judgment.

  If InpREV ≦ PREV_LMSR, it is determined that no restriction is required, and the process proceeds to S236. Otherwise, the process proceeds to S235 for adding a restriction.

  In S235, the target slip rotation speed change amount dtslp2 that is limited by the slip rotation speed change amount is calculated by the following equation.

dtslp2 = mid [dtslp1, DSREV_LM_MAX, DSREV_LM_MIN] (17)
The target slip rotation speed change amount dtslp3 is the target slip rotation speed change obtained by limiting the intermediate one of the target slip rotation speed change amount dtslp1 obtained in S232 and the upper limit value DSREV_LM_MAX and the lower limit value DSREV_LM_MIN. Calculated as the quantity dtslp2.

  On the other hand, in S236 when the restriction on the slip rotation speed change amount is unnecessary, the value dtslp1 obtained in S232 is set as the target slip rotation speed change amount dtslp2.

  Thus, after setting the target slip rotation speed change amount dtslp2 in S235 or S236, in S237, the target slip rotation speed change amount Δ multiplied by the remaining rotation speed limit up to the final target slip rotation speed TGT_SREV (see FIG. 5). Tslip is calculated by the following equation.

ΔTslip = max [dtslp2, (TGT_SREV−Tslip ₂₀ )] (18)
That is, the larger of the difference between the final target slip rotation speed TGT_SREV and the target slip rotation speed Tslip ₂₀ at the previous control or the target slip rotation speed change amount dtslp2 is calculated as the target slip rotation speed change amount ΔTslip. The amount of change is limited so as not to fall below the final target slip rotation speed TGT_SREV.

  On the other hand, in S238 where it is determined that the primary rotational speed InpREV has started to decrease (or remain constant), the target slip rotational speed change amount ΔTslip is set to 0 and the target slip rotational speed of the previous cycle is held.

Next, in S239, the target slip rotation speed Tslip is calculated by the above equation (13) using the calculated target slip rotation speed change amount ΔTslip and the previous target slip rotation speed (Tslip ₂₀ ) (Tslip ₂₀ ). To do.

  This is because the larger of the difference between the value obtained at the previous control plus the target slip rotational speed change amount ΔTslip and the preset engine stall avoidance engine rotational speed (ENSTEREV) and the primary rotational speed InpREV is the target slip rotational speed. Calculate as Tslip.

  That is, the primary rotational speed InpREV is restricted from entering the engine stall determination area by the target slip rotational speed.

  In S240, the time constant TC of the reference model in the region 3 is set to a small fixed value set in advance to improve the response. Note that after the process of S211, the process returns to S10 of FIG.

The slip control is performed by obtaining the target slip rotation speed Tslip according to the change speed ΔInpREV ₂₀ of the primary rotation speed InpREV by S231 to S240 in FIGS.

  During the control of the region 1 in FIG. 11 described above, when the shift starts before the slip rotational speed decreases and falls below the predetermined rotation SlpREV_ED (before shifting to the region 2) (the primary rotational speed does not change with a constant throttle opening). If the area is entered, the process proceeds to area 3.

  In this region 3, since the primary rotational speed hardly changes as shown in FIG. 7, slip control is performed based on the target slip rotation that decreases by a predetermined amount TGT_EREV. When the slip rotation falls below the predetermined rotation SlpREV_ED, the region 2 is shifted.

  In the above-described region 3, when the transmission (CVT or the like) connected to the torque converter starts shifting at the start of slip control, the target slip rotation speed Tslip is set at the engine rotation speed change speed (change amount) TGT_EREV. Reduce gradually.

  That is, the gear ratio also changes according to the change in the throttle opening TVO, and the primary rotational speed InpREV also fluctuates. Therefore, the amount of decrease in the target slip rotational speed Tslip is corrected according to the fluctuation in the gear ratio. In this correction, the amount of decrease in the target slip rotation speed Tslip is corrected to be smaller as the primary rotation speed InpREV increases.

  When the primary rotation speed InpREV is higher than the predetermined value TSDPREV2, it is determined that the shift is started.

  As a result, even when the primary rotational speed InpREV, such as drive slip, is constant, slip control can be performed so that the engine rotational speed changes in advance.

Further, in this region 3, the target slip rotation speed Tslip (slip rotation command value) is obtained by correcting the predetermined engine rotation speed change amount TGT_EREV with the primary rotation speed change amount ΔInpREV ₂₀ during one control cycle. and the amount Dtslp1, as dtslp2 over restrictions on the lower limit thereto, determined by adding the previous target slip speed Tslip _20.

  The target slip rotation speed Tslip is applied when the engine stall avoidance is limited and the target slip rotation speed Tslip is higher than the predetermined slip rotation speed SlpREV_ED. As a result, even if the primary rotation is constant, such as drive slip, not only can the slip control be performed so that the specified engine rotation changes, but the primary rotation speed also changes when the vehicle speed is high and the shift becomes high gear. Accordingly, the slip control can be performed even in a high vehicle speed region by correcting the target slip rotation speed Tslip in accordance with the above.

Further, in the control of the region 1 and the region 3, the target slip rotation speed change amount ΔTslip is limited so as not to fall below the final target slip rotation speed TGT_SREV, and the current target slip rotation change amount When the difference between the target value TGT_SREV and the previous target slip rotation speed Tslip ₂₀ is larger (absolute value), the difference is set as the current target slip change amount (S239). Thus, it is possible to prevent a command value that falls below the final target value with respect to the slip rotation speed to be finally converged, and to prevent overshoot / undershoot of actual slip rotation.

  When the target slip rotation speed Tslip is lower than the predetermined value SREV_LMSR and the primary rotation speed InpREV is higher than the predetermined value PREV_LMSR), the target slip rotation speed change amount is restricted to avoid judder. As this limit value, an upper limit DSREV_LM_MAX and a lower limit DSREV_LM_MIN are set, and these limit values are values dependent on the throttle opening. As a result, judder and early lockup can be avoided, and slip control can be performed smoothly.

  In the above embodiment, as shown in FIGS. 9 and 10, the region is determined by comparing the target slip rotational speed Tslip and the predetermined value SlpREV_ED. However, the region is determined by comparing the actual slip rotational speed and the predetermined value. May be performed.

  As described above, the slip converter for a torque converter according to the present invention can be applied to a vehicle transmission having excellent drivability.

The schematic block diagram of the torque converter which shows one Embodiment of this invention. Functional block diagram of the controller. The map which shows the relationship between the turbine rotational speed of a torque converter, and a slip rotational speed gain. The map which shows the relationship between lockup clutch fastening pressure and lockup clutch capacity. It is a graph which shows the control state in the area | region 1 of slip control, and shows the relationship between engine rotational speed, primary rotational speed, target slip rotational speed, target slip rotational speed command value, and time. It is a graph which shows the control state in the area | region 2 of slip control, and shows the relationship between engine rotational speed, primary rotational speed, target slip rotational speed, target slip rotational speed command value, and time. It is a graph which shows the control state in the area | region 3 of slip control, and shows the relationship between engine rotational speed, primary rotational speed, target slip rotational speed, target slip rotational speed command value, and time. The first half of the determination process in the flowchart showing an example of the process performed by the controller. Similarly, the determination units in the areas 1 to 3 in the latter half of the determination process. Similarly, the determination unit for the areas 2 and 3 in the latter half of the determination process. Similarly, the flowchart which performs the process of the area | region 1. FIG. Similarly, the flowchart which performs the process of the area | region 2. FIG. Similarly, the flowchart which performs the process of the area | region 3. FIG. A conventional example is shown, and the relationship between engine speed, input shaft speed, vehicle speed, and time is shown.

Explanation of symbols

1 Torque converter 2 Lock-up clutch 3 Lock-up control valve 4 Lock-up solenoid 5 Controller

Claims (24)

A torque converter provided with a lock-up clutch and interposed between the engine and the automatic transmission;
A target slip rotation calculating unit for obtaining a target slip rotation speed of the lock-up clutch from the driving state of the vehicle when the torque converter shifts from the converter state to the slip state based on the driving state of the vehicle;
An actual slip rotation speed detecting means for detecting an actual slip rotation speed from the pump impeller rotation speed and the turbine rotation speed of the torque converter;
Feedback compensation means for calculating an output for controlling the engagement state of the lockup clutch by feedback control based on the target slip rotation speed and the actual slip rotation speed;
Feedforward compensation means for calculating an output for controlling the engagement state of the lockup clutch by feedforward control based on the target slip rotation speed;
Slip control means for controlling the engagement state of the lockup clutch based on the command value of the feedback compensation means and the command value of the feedforward compensation means;
In a slip-up control device for a lock-up clutch provided with
A turbine rotation change speed calculation unit that calculates a change speed of the turbine rotation speed,
The target slip rotation calculation unit calculates the target slip rotation speed so that the decrease speed increases as the increase speed of the turbine rotation speed increases .
The slip control device for a torque converter, wherein the slip control means controls the actual slip rotation speed to follow a target slip rotation speed. The target slip rotation calculation unit has a target slip rotation change amount calculation unit for calculating a change speed of the target slip rotation speed, and a target obtained by adding the previous target slip rotation speed to the change speed of the target slip rotation speed as a target. The slip control device for a torque converter according to claim 1, wherein the slip control device calculates the slip rotation speed. The target slip rotation change amount calculation unit includes a turbine rotation change rate calculation unit that calculates a change rate of the turbine rotation speed. The difference between the predetermined slip rotation speed and the previous target slip rotation speed change rate The slip control device for a torque converter according to claim 2, wherein a change speed of the target slip rotation speed is calculated by multiplying a value based on a change ratio of the rotation speed. The target slip rotation calculation unit includes a pump impeller rotation change amount calculation unit that calculates a change speed of the pump impeller rotation speed, and regulates a change speed of the target slip rotation speed according to the change speed of the pump impeller rotation speed. The slip control device for a torque converter according to claim 2 or claim 3, wherein: The target slip rotation change amount calculation unit sets and regulates an upper limit value or a lower limit value of a change speed of the target slip rotation speed so as to prevent a sudden change in the change speed of the pump impeller rotation speed. 4. A slip control device for a torque converter according to 4. The target slip rotation calculation unit switches a control region based on a target slip rotation speed or a turbine rotation speed, and a predetermined slip rotation speed is set as a switching determination value for the control region. A slip converter for a torque converter as described in 1. 2. The target slip rotation calculation unit, when the target slip rotation speed or the actual slip rotation speed reaches a predetermined slip rotation speed, performs a delay process on the target slip rotation speed by switching a control region. The slip control apparatus of the torque converter as described. The slip control device for a torque converter according to claim 6 or 7, wherein the predetermined slip rotation speed is a value larger than a final target slip rotation speed obtained according to an operation state. The slip of the torque converter according to claim 7, wherein the target slip rotation calculation unit performs the delay process on the target slip rotation speed with a value based on the target slip rotation speed at the time of switching the control region as an initial value. Control device. 10. The initial value is a difference between a target slip rotation speed based on a final target slip rotation speed obtained according to an operation state and a target slip rotation speed at the time of switching a control region. A slip converter for a torque converter as described in 1. 11. The slip control device for a torque converter according to claim 10, wherein a target slip rotation speed based on the final target slip rotation speed is limited so as to prevent a stall of an engine connected to the pump impeller side. . 12. The slip control device for a torque converter according to claim 7, wherein the delay process is a first-order delay. 12. The slip converter for a torque converter according to claim 7, wherein the delay process sets a time constant based on an operation amount of an accelerator pedal. The target slip rotation calculating unit gradually decreases the target slip rotation speed by a predetermined pump impeller rotation speed change amount when a shift is started at the start of slip control. The slip control apparatus of the torque converter as described. The slip control device for a torque converter according to claim 14, wherein the target slip rotation calculation unit determines the start of shifting when the turbine rotation speed is greater than a predetermined value. The target slip rotation calculation unit includes a target slip rotation change amount calculation unit that calculates a change speed of a target slip rotation speed, a pump impeller rotation change amount calculation unit that calculates a change speed of the pump impeller rotation speed, and the turbine rotation A turbine rotation change amount calculation unit for calculating a speed change speed, and calculating a change speed of a target slip rotation speed from a change speed of a pump impeller rotation speed and a change speed of a previous turbine rotation speed. The slip control device for a torque converter according to claim 14 or 15. The torque converter slip control according to claim 16, wherein the target slip rotation change amount calculation unit regulates a change speed of the target slip rotation speed so as to prevent a stall of an engine connected to the pump impeller. apparatus. The target slip rotation calculating section regulates the target slip rotation speed so as not to fall below a final target slip rotation speed obtained according to an operating state. The slip converter for a torque converter according to any one of claims 17 to 17. The target slip rotation change amount calculation unit calculates the current target slip rotation speed from the absolute value of the difference between the final target slip rotation speed obtained according to the operation state and the previous target slip rotation speed change speed. 18. The absolute value of the difference is set as the change speed of the target slip rotation speed when the change speed is larger. A slip converter for a torque converter as described in 1. The target slip rotation change amount calculation unit limits the change rate of the target slip rotation speed when the target slip rotation speed is less than the first limit value and the turbine rotation speed exceeds the second limit value. 18. The slip converter for a torque converter according to claim 4, wherein the slip control device is for a torque converter. 21. The slip control device for a torque converter according to claim 20, wherein the limitation of the change speed of the target slip rotation speed is performed with an upper limit value and a lower limit value set in advance in order to avoid judder or early engagement. 21. The slip control device for a torque converter according to claim 20, wherein a limit value corresponding to a throttle opening is used to limit the change speed of the target slip rotation speed. 18. The target slip rotation calculation unit limits a target slip rotation speed so as to prevent the engine from stalling. 18. The claim 1, wherein the target slip rotation calculation unit limits the target slip rotation speed. Torque converter slip control device. The target slip rotation speed is limited when the current target slip rotation speed is smaller than a difference between a predetermined pump impeller rotation speed that prevents the engine from stalling and a turbine rotation speed. The slip control device for a torque converter according to any one of claims 1 to 6, or 14 to 17, wherein the target slip rotation speed is set.

Images