JP2012021549A - Lock-up clutch controller for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control the slip amount of a lock-up clutch in transition from lock-up OFF to lock-up ON when lock-up control is started.SOLUTION: When a lock-up clutch command hydraulic pressure in transition from lock-up OFF to lock-up ON is learned, arrival time from a time point when engagement pressure fixing control ends till an actual slip ratio reaches a predetermined target value or a predetermined value around the value is measured, and a learned value of the command hydraulic pressure is updated based on the length of the arrival time. An original initial control command pressure is corrected based on the learned value, and engaging control of a lock-up clutch in an OFF state is started according to the corrected initial control command pressure. Thus, the slippage of the lock-up clutch in transition from lock-up OFF to lock-up ON when lock-up clutch control is started can be properly controlled, and thereby heating, lowering of fuel economy or occurrence of engagement shock resulting from unnecessary occurrence of clutch slippage can be prevented.

Description

  The present invention relates to a lockup clutch control device for an automatic transmission that controls a slip amount of a lockup clutch. In particular, the lockup clutch command hydraulic pressure instructed in accordance with the transition from the lockup off to the lockup on at the time of the lockup clutch control is learned, and the slip of the lockup clutch at the next same control is learned based on the learning result. The present invention relates to a technique for appropriately controlling the amount.

  Generally, in the engagement control of a lock-up clutch (LC) provided in a torque converter of an automatic transmission, a lock-up on / off mechanism that directly connects an engine output shaft and an automatic transmission mechanism input shaft. In addition to control for turning off, slip control for maintaining the lockup clutch in a slip state is performed for the purpose of improving fuel consumption and reducing fastening shock. In this slip control, the actual differential rotation (actual slip amount or actual slip ratio) between the engine output shaft and the input shaft of the automatic transmission mechanism is desired from the viewpoint of reducing engine vibration transmission and preventing fluctuations in LC transmission torque. It is preferable to control the slip amount by hydraulic control so that the target differential rotation (target slip amount or target slip ratio) is achieved, but especially when the accelerator operation by the driver is not constant and the engine torque fluctuates. In such cases, it is difficult to control the actual slip amount to the target slip amount only by simple feedback control.

  Therefore, not only the feedback control value is calculated based on the target slip amount and the actual slip amount, but also the feedforward control value corresponding to the engine torque is calculated, and the feedforward control value and the feedback control value are calculated. Conventionally, the slip control is performed using the added value. An example of such a technique is an apparatus disclosed in Patent Document 1, for example. In the conventional device described in Patent Document 1, the feedforward control value corresponding to the engine torque during slip control is learned and corrected according to the comparison result between the target slip amount and the actual slip amount, and the feed after the learning correction is corrected. A value obtained by adding the feedback control value to the forward control value is output as the lockup clutch command hydraulic pressure.

Japanese Patent No. 2985102

  However, in the conventional device as described above, when the lockup clutch control for starting the engagement of the lockup clutch in the clutch-off state is started, the lock equivalent to the conventionally known feedback control that suddenly achieves a preset target slip ratio is achieved. Because the up-clutch command hydraulic pressure is output, the target slip ratio is more tight in a short time (for example, to increase fuel efficiency) (ie, almost differential rotation between the output shaft of the engine and the input shaft of the automatic transmission mechanism) The higher the lockup clutch command hydraulic pressure (control initial command pressure) is output, the more it is set to approach the slip ratio where no slip occurs (for example, a state where the slip rate is 90 to 100%). The up clutch is suddenly engaged and a large engagement shock is likely to occur. Vibration there is a problem that, occurs.

The present invention has been made in view of the above points, and learns the lockup clutch command hydraulic pressure at the time of shifting from lockup off to on each time the lockup clutch control is started, and the lockup clutch in the clutch off state is learned. When the lockup clutch control is started after the next time when the engagement is started, the lockup clutch engagement control is started according to the control initial command pressure corrected based on the learning result (learned value). An object of the present invention is to provide a lockup clutch control device for an automatic transmission that can appropriately control the slip amount of the clutch.
In this specification, the lockup clutch command hydraulic pressure that is instructed at the start of the lockup clutch control is referred to as a control initial command pressure (hereinafter referred to as an initial pressure or a shelf pressure for convenience), and is specified during addition control or cruise feedback control. It is distinguished from the lockup clutch command hydraulic pressure.

  According to a first aspect of the present invention, there is provided a lockup clutch control device for an automatic transmission, wherein the lockup clutch is configured so that an actual slip ratio of the lockup clutch (7) of the automatic transmission (1) becomes a predetermined target value. (7) In the lockup clutch control device (14) of the automatic transmission (1) for controlling the engagement pressure, detection means (3, 4, 11) for detecting engine torque, accelerator pedal opening, or throttle opening; The determination means (E) for determining whether or not the engagement control of the lock-up clutch (7) in the clutch-off state is started, and the engagement control of the lock-up clutch (7) in the clutch-off state is started Learning start determination means (A1) for determining whether or not a predetermined learning start condition is satisfied, and the lockup clutch when the learning start condition is satisfied 7) Learning means (A2) for learning the command hydraulic pressure for instructing the engagement pressure, and the original control initial command for instructing the engagement pressure when starting the engagement control of the lock-up clutch (7) in the clutch-off state A determination means (B) for determining a pressure based on the detected engine torque, accelerator pedal opening or throttle opening, and learning correction of the determined original control initial command pressure according to a learning result of the command hydraulic pressure The learning means (A2) includes correction means (B) and control means (8) for starting engagement control of the lockup clutch (7) in a clutch-off state according to the corrected control initial command pressure. The engine torque or accelerator pedal opening or throttle detected until the actual slip rate reaches within a predetermined target value or a predetermined value close to the predetermined target value from the start of the engagement control. The learning value of the command hydraulic pressure is stored for each learning region corresponding to the average value of the valve opening, and the actual slip ratio reaches within a predetermined target value or a predetermined value close to the predetermined target value from the time when the constant fastening pressure control is completed. And the learning value is updated based on the length of the measured arrival time.

  According to the present invention, as learning of the lockup clutch command hydraulic pressure at the time of transition from lockup-off to lockup-on, the actual slip ratio is reached from the predetermined end time until the actual slip ratio reaches a predetermined target value or a predetermined value close thereto. The arrival time is measured, and the learning value is updated based on the length of the measured arrival time. Then, in order to instruct the engagement pressure when starting the engagement of the lockup clutch in the clutch-off state, the original control initial command pressure determined based on the engine torque, the accelerator pedal opening, or the throttle opening is Correction is made based on the learning value, and engagement control of the lock-up clutch in the clutch-off state is started in accordance with the corrected control initial command pressure. By doing this, when the engagement of the lock-up clutch in the clutch-off state is started, the slip amount of the lock-up clutch at the time of transition from the lock-up off to the lock-up on can be appropriately controlled. It is possible to prevent heat generation and deterioration of fuel consumption due to excessive generation of clutch slip due to the control initial command pressure being too low, or occurrence of a fastening shock due to the control initial command pressure being too high. It becomes like this.

  According to a second aspect of the present invention, there is provided a lockup clutch control device for an automatic transmission in which the actual slip ratio of the lockup clutch (7) of the automatic transmission (1) is a predetermined target value. (7) In the lockup clutch control device (14) of the automatic transmission (1) for controlling the engagement pressure, detection means (3, 4, 11) for detecting engine torque, accelerator pedal opening, or throttle opening; The determination means (E) for determining whether or not the engagement control of the lock-up clutch (7) in the clutch-off state is started, and the engagement control of the lock-up clutch (7) in the clutch-off state is started And (A1) learning start determining means for determining whether or not a predetermined learning start condition is satisfied, and when the learning start condition is satisfied, the lockup clutch 7) Learning means (A2) for learning the command hydraulic pressure for instructing the engagement pressure, and the original control initial command for instructing the engagement pressure when starting the engagement control of the lock-up clutch (7) in the clutch-off state A determination means (B) for determining a pressure based on the detected engine torque, accelerator pedal opening or throttle opening, and learning correction of the determined original control initial command pressure according to a learning result of the command hydraulic pressure The learning means (A2) includes correction means (B) and control means (8) for starting engagement control of the lockup clutch (7) in a clutch-off state according to the corrected control initial command pressure. , Before every learning region corresponding to the average value of engine torque or accelerator pedal opening or throttle opening detected from the start of the engagement control until the end of constant engagement pressure control The learning value of the command hydraulic pressure is stored, and the deviation between the actual slip ratio when the engagement pressure constant control is finished and the target value when the engagement pressure constant control is finished is calculated, and based on the magnitude of the calculated deviation And updating the learning value. By doing this as well, the slip amount of the lock-up clutch at the time of transition from lock-up off to lock-up on can be appropriately controlled as described above, and heat generated due to excessive clutch slippage, deterioration of fuel consumption, or engagement shock Can be prevented.

  According to a third aspect of the present invention, there is provided a lockup clutch control device for an automatic transmission in which the actual slip ratio of the lockup clutch (7) of the automatic transmission (1) becomes a predetermined target value. (7) In the lockup clutch control device (14) of the automatic transmission (1) for controlling the engagement pressure, detection means (3, 4, 11) for detecting engine torque, accelerator pedal opening, or throttle opening; The determination means (E) for determining whether or not the engagement control of the lock-up clutch (7) in the clutch-off state is started, and the engagement control of the lock-up clutch (7) in the clutch-off state is started And (A1) learning start determining means for determining whether or not a predetermined learning start condition is satisfied, and when the learning start condition is satisfied, the lockup clutch 7) Learning means (A2) for learning the command hydraulic pressure for instructing the engagement pressure, and the original control initial command for instructing the engagement pressure when starting the engagement control of the lock-up clutch (7) in the clutch-off state A determination means (B) for determining a pressure based on the detected engine torque, accelerator pedal opening or throttle opening, and learning correction of the determined original control initial command pressure according to a learning result of the command hydraulic pressure The learning means (A2) includes correction means (B) and control means (8) for starting engagement control of the lockup clutch (7) in a clutch-off state according to the corrected control initial command pressure. , Before every learning region corresponding to the average value of engine torque or accelerator pedal opening or throttle opening detected from the start of the engagement control until the end of constant engagement pressure control The learning value of the command oil pressure is stored, and the deviation between the actual slip ratio at the start of the engagement control and the actual slip ratio at the end of the engagement pressure constant control is calculated, and the learning is performed based on the magnitude of the calculated deviation. It is characterized by updating the value. By doing this as well, the slip amount of the lock-up clutch at the time of transition from lock-up off to lock-up on can be appropriately controlled as described above, and heat generated due to excessive clutch slippage, deterioration of fuel consumption, or engagement shock Can be prevented.

  Note that the reference numerals in the parentheses described above exemplify the corresponding constituent elements in the embodiments described later for reference.

  According to the present invention, the lockup clutch command hydraulic pressure instructed at the time of transition from lockup off to lockup on is learned, and the lockup clutch in the clutch off state is engaged based on the learning result (learned value). By correcting the original control initial command pressure at the time of starting, the slip amount of the lockup clutch at the time of shifting from the lockup off to the lockup on at the next control can be appropriately controlled. As a result, it is possible to prevent heat generation and fuel consumption deterioration due to excessive generation of clutch slip due to the control initial command pressure being too low, or the occurrence of a fastening shock due to the control initial command pressure being too high. It has the effect of being able to do it.

1 is a schematic view showing an embodiment of an automatic transmission to which a lockup clutch control device for an automatic transmission according to the present invention is applied. It is a block diagram of a lockup clutch control device. It is a timing chart for explaining learning of lockup clutch command oil pressure. It is a flowchart which shows one Example of a lockup clutch command oil pressure learning process. It is a figure which shows one Example of a learning map. It is a flowchart which shows one Example of a lockup clutch command hydraulic pressure determination process. It is a flowchart which shows another Example of a lockup clutch instruction | command oil pressure learning process. It is a flowchart which shows another Example of a lockup clutch instruction | command oil pressure learning process.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an embodiment of an automatic transmission to which a lockup clutch control device for an automatic transmission according to the present invention is applied. As shown in FIG. 1, an automatic transmission 1 connected to an engine 2 that is a power drive source is roughly divided into a torque converter (TC) having an automatic transmission mechanism (AT) 5 and a lock-up clutch (LC) 7. 6. A configuration comprising a hydraulic control circuit 8, wherein the torque converter 6 is interposed between the output shaft (not shown) of the engine 2 and the main shaft MS of the input shaft of the automatic transmission mechanism 5. It has become. That is, the driving force generated by the engine 2 is transmitted to driving wheels (not shown) of the vehicle via the torque converter 6 provided with the lock-up clutch 7, the automatic transmission mechanism 5, and the like. .

  The torque converter 6 performs torque transmission between the engine 2 and the input shaft of the automatic transmission mechanism 5 via a fluid in a state where the lock-up clutch 7 is released (lock-up off), while the lock-up clutch 7 is locked up. In a state where the clutch 7 is completely engaged (engaged) without slipping (lock-up on), the engine 2 and the main shaft MS of the input shaft of the automatic transmission mechanism 5 are substantially directly connected to each other without depending on the fluid. Torque is directly transmitted between the engine 2 and the main shaft MS of the input shaft. Such control for engaging / disengaging the lockup clutch 7 (including slip control for maintaining the lockup clutch 7 in a slip state), transmission control in the automatic transmission mechanism 5, and the like are performed by hydraulic control by the hydraulic control circuit 8. Note that the configuration of the automatic transmission mechanism 5 and the transmission control of the automatic transmission mechanism 5 by the hydraulic control circuit 8 are not related to the essence of the present invention and will not be described.

  As a hardware configuration of the hydraulic control circuit 8 for engaging / disengaging the lockup clutch 7, a well-known configuration may be employed as it is. As an example, a conventionally known hydraulic control circuit 8 that engages / releases the lockup clutch 7 using a lockup relay valve, a lockup control valve, a linear solenoid valve or the like will be briefly described. The lockup relay valve is a valve for switching the engagement / release of the lockup clutch 7, and the switching is performed depending on whether or not the control hydraulic pressure generated by the linear solenoid valve exceeds a predetermined threshold value. By gradually increasing or decreasing the control hydraulic pressure at the time of switching by means of a linear solenoid valve, the lockup relay valve, in combination with the lockup control valve, makes the lockup clutch 7 smooth (when shifting from lockup off to on). It can be fastened or released (while slipping).

  On the other hand, the lock-up control valve has an engagement pressure when the lock-up clutch 7 is engaged (or released), and its slip amount becomes a predetermined target value (target slip amount or target slip ratio, etc.). The fastening pressure is controlled by using a control hydraulic pressure generated by a linear solenoid valve as a control pilot pressure. Therefore, by controlling the control hydraulic pressure of the linear solenoid valve, the lockup clutch 7 can be (sliding) fastened with a necessary and sufficient hydraulic pressure corresponding to the output torque of the engine. Thus, the hydraulic control circuit 8 can perform not only the switching control for simply engaging / disengaging the lockup clutch 7, but also the slip control for maintaining the lockup clutch 7 in the slip state. It has become. Control of the lock-up clutch 7 such as the switching control and slip control by the hydraulic control circuit 8 is performed according to an instruction from the ECU 14.

  The ECU 14 includes a CPU, a ROM, a RAM, an input / output interface, and the like, and is a microcomputer that realizes a predetermined function according to various control programs stored in the ROM while using a temporary storage function of the RAM. In this embodiment, the ECU 14 functions as a lock-up clutch control device for an automatic transmission according to the present invention. A lock-up clutch command oil pressure learning process (see FIG. 4) and a lock-up clutch command oil pressure determination process described later. By executing a computer program such as (see FIG. 6), the lockup clutch command oil pressure is learned at the time of transition from lockup off to on, and the original lockup clutch is based on the learning result (learned value). Operation of the hydraulic control circuit 8 by correcting the command hydraulic pressure and outputting the corrected lockup clutch command hydraulic pressure as a control initial command pressure at the start of lockup clutch control for starting engagement of the lockup clutch in the off state Is to control. Details of such processing will be described later.

  The ECU 14 detects the engine torque signal from the engine torque sensor 3 that detects the output torque of the engine 2 and the throttle opening in order to reflect, for example, the load of the engine 2 and the state of the engine 2 and the transmission 1. The throttle opening signal from the throttle sensor 4, the LC transmission torque signal from the LC transmission torque sensor 9 that detects the LC transmission torque transmitted from the lockup clutch 7 to the automatic transmission mechanism 5, and the main shaft MS of the automatic transmission mechanism 5. From the main shaft rotation speed signal from the rotation speed sensor 10 that detects the rotation speed, from the accelerator pedal opening signal from the accelerator pedal sensor 11 that detects the depression amount of the accelerator pedal, from the shift sensor 12 that detects the shift (shift stage) position Various signals such as shift stage signals are input. It has become. Further, as other signals, various signals such as engine intake air temperature, engine coolant temperature, air conditioner on / off state, transmission lubricant oil temperature, and the like are input from other sensors 13 that can detect them. Of course, signals other than those described here may be input.

  Note that the lockup clutch control device for an automatic transmission according to the present invention is not limited to one that executes a computer program such as the ECU 14 described above, and may be constituted by dedicated hardware. It is.

  Next, details of the ECU 14 will be described with reference to FIG. FIG. 2 is a block diagram of the lockup clutch control device (ECU 14). As shown in FIG. 2, in this embodiment, the ECU 14 includes a lockup clutch command hydraulic pressure learning means A, a lockup clutch command hydraulic pressure determination means B, a target slip ratio setting means C, an actual slip ratio detection means D, and a lockup start. It has determination means E and learning value storage means F.

  The lockup start determination means E determines whether or not the engagement of the lockup clutch 7 in the off state is started. When the engagement start of the lockup clutch 7 is performed, the engagement start is output to the lockup clutch command hydraulic pressure learning means A and the lockup clutch command hydraulic pressure determination means B. The lockup clutch command hydraulic pressure learning means A is for learning the lockup clutch command hydraulic pressure at the time of transition from lockup off to on for each shift stage specified by the shift stage signal. Learning is started in response to the start of engagement being output by E.

  The lockup clutch command hydraulic pressure learning means A includes a learning start determining means A1 and a learning means A2. The learning start determination means A1 determines whether a learning start condition for learning the lockup clutch command hydraulic pressure is satisfied. In the present embodiment, the engine intake air temperature, the engine coolant temperature, etc. are within a predetermined range, and the air conditioner is in an off state for a predetermined time or longer (engine-side stability condition), and the transmission The oil temperature of the lubricating oil 1 is within a predetermined range, and the transmission 1 that starts up without delay in the hydraulic pressure for transmission control is in a stable operating state (transmission-side stability condition), and is in an off state The displacement of the accelerator pedal opening (or engine torque or throttle opening) is within a certain value before a certain time (see t0 to t1 shown in FIG. 3 described later) until the lockup clutch 7 is started to be engaged. When all of the conditions within the small range (engine torque stabilization conditions) are satisfied at the same time , It is determined that the learning start condition is satisfied.

  The learning means A2 learns the lockup clutch command hydraulic pressure within the learning period from the start of the engagement of the lockup clutch 7 to the cruise feedback control. The learning of the lockup clutch command oil pressure (reflection to the learning value) is performed every time the lockup clutch 7 is engaged, and the learning result (learning value) at that time is stored in the learning value storage means F. The learning map (see FIG. 5 described later) is reflected. Here, FIG. 3 is a timing chart for explaining learning of the lockup clutch command hydraulic pressure. Hereinafter, the learning timing of the lockup clutch command hydraulic pressure will be described with reference to the timing chart of FIG.

  It is determined by the learning start determination means A1 that the learning start condition that the engine side stability condition, the transmission side stability condition, and the engine torque stability condition are all satisfied at the same time is satisfied (here, all the flags corresponding to the respective conditions are “ 1 ”), and when the engagement start determination (output) by the lockup start determination means E is made, that is, the rising start time t2 of the control hydraulic pressure for the lockup clutch 7 is set as the learning start time. On the other hand, the time point t4 at which the cruise feedback control is started (that is, until the shelf pressure control and the addition control are finished, or until the actual slip rate is within a certain value from the target slip rate) is set as the learning end point.

  In the present embodiment, for example, in accordance with the addition control started from the shelf pressure control end time t3 within the learning period from the learning start t2 to the learning completion t4 based on the lockup clutch command oil pressure that fluctuates as shown in the figure. The time until t4 when the actual slip ratio reaches within a certain value from the target slip ratio (that is, the addition control time) is measured, and the initial time at the start of the next lock-up clutch control according to the length of the measured addition control time Learning to raise and lower the pressure is performed. In this embodiment, when the addition control time is short, negative learning for lowering the initial pressure is performed, and when the addition control time is long, positive learning for increasing the initial pressure is performed. Reflected in the learning map. A method of reflecting the learning value in such a learning map will be described later (see FIG. 5).

  The target slip ratio is determined by target slip ratio setting means C, and the actual slip ratio is determined by actual slip ratio detection means D. Since the method for determining each slip ratio by the target slip ratio setting means C and the actual slip ratio detection means D may be any known method, description thereof will be omitted.

  Returning to the description of FIG. 2, the lockup clutch command hydraulic pressure determination means B determines the lockup clutch command hydraulic pressure, and in this embodiment, the lockup start determination means E outputs the engagement start in particular. Accordingly, the initial pressure when starting the engagement of the lockup clutch 7 in the off state is determined for each shift stage specified by the shift stage signal, and is output to the hydraulic pressure control circuit 8. The initial pressure is the original initial pressure determined according to the accelerator pedal opening (or engine torque or throttle opening) (referred to simply as the original command oil pressure to distinguish it from the corrected initial pressure). It is determined by correcting according to the learning map stored in the value storage means F. The original command hydraulic pressure is not limited to the engagement pressure determined according to the accelerator pedal opening (or engine torque or throttle opening), but contributes to feedforward control determined according to the LC transmission torque. The fastening pressure may include a feedforward command hydraulic pressure.

  Next, the process of learning the lockup clutch command hydraulic pressure described above will be described with reference to FIG. FIG. 4 is a flowchart showing an embodiment of the lockup clutch command oil pressure learning process. As described above, when learning the lockup clutch command oil pressure or determining the initial pressure at the start of lockup clutch engagement, either the accelerator pedal opening, the engine torque or the throttle opening is monitored. In the following, a case where the accelerator pedal opening degree is monitored as a representative will be described as an example for easy understanding of the description.

  In step S1, it is determined whether or not the engine-side stability condition flag is “1”. If it is determined that the engine-side stability condition flag is “1” (YES in step S1), it is determined whether the transmission-side stability condition flag is “1” (step S2). If it is determined that the transmission-side stability condition flag is “1” (YES in step S2), the displacement is predetermined and constant at the accelerator pedal opening (or engine torque or throttle opening, the same applies hereinafter). It is determined whether or not the value is within a value and continued for a certain period of time, that is, the engine torque is stable (step S3). On the other hand, when it is determined that the engine-side stability condition flag is not “1”, the transmission-side stability condition flag is not “1”, or the engine torque is not stable (any of steps S1 to S3 is NO). Then, the process ends. That is, the processes from the above steps S1 to S3 are processes for determining whether or not the engine-side stability condition, the transmission-side stability condition, and the engine torque stability condition are satisfied, and even one of these conditions is satisfied. If not, the process ends without learning the lockup clutch command hydraulic pressure.

  On the other hand, when the engine-side stability condition, the transmission-side stability condition, and the engine torque stability condition are all satisfied (steps S1 to S3 are all YES), the engine torque is in a stable state and the learning start time t2 is determined. Start learning. First, engagement of the lockup clutch 7 is started, and whether or not the lockup clutch control is in shelf pressure control or addition control, or a value obtained by subtracting the actual slip ratio from the shelf pressure control or the target slip ratio. Is determined to be smaller than a predetermined value (that is, whether the actual slip ratio has reached within a certain value from the target slip ratio) (step S4). When it is determined that the lock-up clutch control is under shelf pressure control or addition control, or during shelf pressure control or the value obtained by subtracting the actual slip rate from the target slip rate is smaller than a predetermined value (YES in step S4) Then, the average value of the accelerator pedal opening from the start of engagement to the determination time is calculated (step S5). In step S6, target addition control times T1 and T2 (however, T1 <T2 in this case), which serve as a guide for the execution time of the addition control executed after the shelf pressure control based on the accelerator pedal opening actually measured at that time, are obtained. calculate. For the target addition control times T1 and T2, refer to, for example, data obtained by mapping the addition control time according to the accelerator pedal opening in advance obtained from an actual test result in which proper lockup clutch control is performed. It is required by doing.

  In step S4, it is determined that the lock-up clutch control is not in shelf pressure control or addition control, or is not in shelf pressure control, and the value obtained by subtracting the actual slip ratio from the target slip ratio is smaller than a predetermined value, and learning completion time t4. Is determined (NO in step S4), the target addition control times T1 and T2 are compared with the addition control time (actual value) required for the addition control in the lock-up clutch control being executed (step S7). And step S9), different processes according to the comparison results are executed. When the actually measured addition control time is shorter than the target addition control time T1 (YES in step S7), the average value of the accelerator pedal opening obtained in step S5 in the learning map stored in the learning value storage means F ( The learning result is reflected by subtracting the learning value of the corresponding region based on the average accelerator pedal opening) (step S8). That is, the fact that the actual addition control time is shorter than the target addition control time T1 indicates that the actual slip ratio has reached the target slip ratio in a time shorter than the target, and such an operation is a rapid engagement. Therefore, in order to correct such an operation next time, more specifically, minus learning is performed to reduce the learning value so that the addition control is executed over a relatively long time so as not to cause the rapid fastening.

  On the other hand, when the actually measured addition control time is longer than the target addition control time T2 (which is naturally longer than the target addition control time T1) (step S7 is NO and step S9 is YES), the learned value storage means F The learning result is reflected by adding the learning value of the corresponding region based on the average value of the accelerator pedal opening (average accelerator pedal opening) obtained in step S5 in the learning map stored in step S10 (step S10). That is, the fact that the actually measured addition control time is longer than the target addition control time T2 indicates that the actual slip ratio has reached the target slip ratio in a longer time than the target, and such an operation causes a slip with heat generation. In order to correct such operation next time because it is a gradual fastening that can occur over a long period of time, more specifically, the learning value is added to end the addition control in a short period of time so as not to cause the above-mentioned slipping with heat generation. Do positive learning. Thus, the learning period is from the start of engagement of the lockup clutch 7 to the cruise feedback control, and the lockup clutch command oil pressure is learned within the learning period. When the actually measured addition control time is within the range of the target addition control times T1 and T2 (both steps S7 and S9 are NO), heat generation due to excessive clutch slippage, deterioration of fuel consumption, or engagement shock Assuming that appropriate lockup clutch control that does not occur is performed, learning of the lockup clutch command hydraulic pressure by the negative learning or the positive learning is not performed.

  Here, a method of reflecting the learning result (learning value) on the learning map will be described. FIG. 5 is a diagram illustrating an example of a learning map. This learning map is prepared for each shift stage. The learning map is data in which the relationship between the learning area based on the accelerator pedal opening (accelerator pedal opening area) and the learning value is mapped. In FIG. 5, the learning area is divided into nine areas (0/8 to 8/8). ) Shows what was divided. The reason why the learning area is divided into a plurality of areas in this manner is that, for example, variations in engine torque do not necessarily occur equally at each opening of the accelerator pedal opening. For example, if the engine torque fluctuates slightly only in the region where the accelerator pedal opening is in the vicinity of full open, if the learned value is reflected in the entire region of the accelerator pedal opening based on this, On the other hand, inappropriate learning is performed on the area. Therefore, the accelerator pedal opening is divided into nine, and the learning value of only the portion corresponding to this is updated based on the past addition control time corresponding to this.

  Note that if the number of divisions is set too large, the amount of information corresponding to the region for learning correction may be reduced, and there may be a region where learning correction is performed properly and a region where learning correction is not performed properly. It is not suitable, and too little is not suitable for the reasons described above. Therefore, 9 divisions are adopted in this embodiment.

  The learned value is reflected every time the lockup clutch command hydraulic pressure is learned, but the accelerator pedal opening range that reflects the learned value is determined based on the average accelerator pedal opening. When the average accelerator pedal opening is, for example, “1.5 / 8”, both the accelerator pedal opening areas “1/8” and “2/8” indicate that the average accelerator pedal opening area is, for example, “6.2 / In the case of “8”, both the accelerator pedal opening regions “6/8” and “7/8” (not shown) are determined as regions reflecting the learning value.

  On the other hand, the learning result (learned value) reflected in each region is determined according to a predetermined ratio based on the average accelerator pedal opening. Note that, in the learning map in the initial state where learning has not been performed once, all the learning values of all accelerator pedal opening regions are “0”. Specifically, when the average accelerator pedal opening is, for example, “1.5 / 8”, the learning value reflected in both the accelerator pedal opening regions “1/8” and “2/8” is “ When the average accelerator pedal opening is, for example, “6.2 / 8”, the learning values reflected in the region “6/8” and the region “7/8” are “0.8 ( 1-0.2) "and" 0.2 (1-0.8) ".

  When the learning result is reflected on the learning map, if the learning is negative, the learning value to be reflected is subtracted (see step S8 in FIG. 4). If the learning is positive, the learning value to be reflected is Add (see step S10 in FIG. 4). According to the above method, for example, when the first learning is performed and the average accelerator pedal opening at that time is “1.5 / 8” and the learning is negative, the area as shown in FIG. The learning value of “−0.5”, which is the learning result, is directly reflected on “1/8” and the region “2/8” (when the learning values of the learning map in the initial state are all “0”). When the second learning is continued and the average accelerator pedal opening at that time is “1.25 / 8” and the learning is positive learning, the same region “1/8” and region “2 /” as the first learning are performed. Since “+0.75 (1-0.25)” and “+0.25 (1-0.75)”, which are the second learning results, are reflected on the learning value of “8”, it is shown in FIG. Thus, at the end of the second learning, the region “1/8” is set to “−0.5 + 0.75 = 0.25”, and the region “2/8” is set to “−0.5 + 0.25 (1-0.75) = − 0.25”. The learning value is updated. In this way, when the learning of the lockup clutch command hydraulic pressure is repeated a plurality of times, a learning map in which learning values are recorded in all areas as shown in FIG. 5C, for example, is obtained.

  Next, processing for determining the lockup clutch command hydraulic pressure will be described. FIG. 6 is a flowchart showing an embodiment of the lockup clutch command hydraulic pressure determination process. Step S11 determines the shelf pressure command time T0 according to the main shaft rotation speed for each shift stage. The shelf pressure command time T0 is a time (t2 to t3 shown in FIG. 3) in which shelf pressure control is performed from the start of lock-up clutch engagement until addition control is started. In step S12, it is determined whether or not the time for starting timing in accordance with the start of engagement of the lockup clutch has passed the shelf pressure command time T0. When it is determined that the shelf pressure command time T0 has not elapsed, that is, when shelf pressure control is being performed (NO in step S12), the feedforward command hydraulic pressure PF is calculated according to a map prepared in advance based on the LC transmission torque. (Step S13). In step S14, the shelf pressure command pressure P0 is calculated based on the accelerator pedal opening (or engine torque or throttle opening, hereinafter the same) for each shift stage. Step S15 calculates a learning pressure PS (correction pressure) for each shift stage based on the accelerator pedal opening actually measured at that time.

  Here, the calculation method of the learning pressure PS (correction pressure) will be specifically described with reference to FIG. An accelerator pedal opening range that refers to a learning value for calculating the learning pressure PS is determined based on the actually measured accelerator pedal opening. The determined learning value of each region is contributed when the learning pressure PS is calculated according to a predetermined ratio based on the accelerator pedal opening. Specifically, when the accelerator pedal opening is, for example, “1.5 / 8”, the accelerator pedal opening areas “1/8” and “2/8” both refer to the learned value. The contribution of the learning value in the region “1/8” is “−0.45 {(−0.6) × (1-0.25)}”, and the contribution of the learning value in the region “2/8” is “−0.125 {(−0.5) × (1−0.75)}”, and the total contribution to the learning pressure PS as a whole is “−0.575”. Alternatively, when the accelerator pedal opening is, for example, “2.75 / 8”, both the accelerator pedal opening areas “2/8” and “3/8” are the accelerator pedal opening areas that refer to the learned values. The contribution of the learning value of the region “2/8” is “−0.125 {(−0.5) × (1-0.75)}”, and the contribution of the learning value of the region “3/8” is “1.5 (2 X0.75) ", and the overall contribution that contributes to the learning pressure PS as a whole is" 1.375 (1.5-0.125) ". Based on the learning pressure specified based on the accelerator pedal opening, the control pressure corresponding to the total contribution is added (when the total contribution is positive) or subtracted (when the total contribution is negative). Thus, the learning pressure PS (correction pressure) is calculated.

  In step S16, the original lock-up clutch command hydraulic pressure (original command hydraulic pressure, sometimes feedforward command hydraulic pressure PF is not added) obtained by adding the calculated feedforward command hydraulic pressure PF and the shelf pressure command pressure P0. The lockup clutch command hydraulic pressure PC (initial pressure) at the start of engagement is determined by correcting the calculated pressure by the calculated learning pressure PS.

  If it is determined in step S12 that the shelf pressure command time T0 has elapsed, that is, if the shelf pressure control is completed and the addition control or the cruise feedback control is being performed (YES in step S12), the conventionally known addition control is performed. And cruise feedback control processing is executed (steps S17 to S25). That is, step S17 determines whether or not the absolute value of the difference between the target slip ratio and the actual slip ratio is greater than a predetermined value. If it is determined that the absolute value of the difference between the target slip ratio and the actual slip ratio is greater than the predetermined value (YES in step S17), it is determined whether the target slip ratio is greater than the actual slip ratio (step S18). ).

  If it is determined that the target slip ratio is greater than the actual slip ratio (YES in step S18), the added hydraulic pressure gradient P1 is calculated with reference to the map based on the accelerator pedal opening for each shift stage (step S19). . In step S20, the control pressure based on the calculated added hydraulic pressure gradient P1 is added to the current lockup clutch command hydraulic pressure PC to determine (update) the lockup clutch command hydraulic pressure PC. On the other hand, if it is determined that the target slip ratio is not greater than the actual slip ratio (NO in step S18), the subtracted hydraulic pressure gradient P2 is calculated with reference to the map based on the accelerator pedal opening for each shift stage ( Step S21). In step S22, the control pressure based on the calculated subtraction hydraulic pressure gradient P2 is subtracted from the current lockup clutch command hydraulic pressure PC to determine (update) the lockup clutch command hydraulic pressure PC.

  In step S17, when it is determined that the absolute value of the difference between the target slip ratio and the actual slip ratio is equal to or less than a predetermined value (NO in step S17), the feedforward command is referred to with reference to the map based on the LC transmission torque. The hydraulic pressure PF is calculated (step S23). Step S24 calculates a feedback command hydraulic pressure PFB that fills the difference between the target slip ratio and the actual slip ratio. In step S25, the calculated feedback command hydraulic pressure PFB is added to the feedforward command hydraulic pressure PF based on the calculated LC transmission torque to determine (update) the lockup clutch command hydraulic pressure PC.

  As described above, in the lockup clutch control device (ECU 14) of the automatic transmission according to the present invention, the time from when the shelf pressure control ends until the actual slip ratio reaches a certain range up to the target slip ratio (that is, Learning time to measure the initial pressure at the start of the next lockup clutch control in accordance with the length of the measured addition control time. The learning value for determining the PS (correction pressure) is updated to learn the lockup clutch command hydraulic pressure.

  Specifically, when the addition control time is less than a certain value, the clutch is excessively grasped, so learning to subtract the initial pressure at the start of the next engagement is performed, and the clutch is engaged over an appropriate time. So that it can be in a state. On the other hand, when the addition control time exceeds a certain value, the clutch slips easily and heat is likely to be generated, so learning to add the initial pressure at the start of the next engagement is performed and the clutch is held in a shorter time. It can be so.

  In this way, the lockup clutch command hydraulic pressure at the time of transition from lockup off to on is learned, and the original command hydraulic pressure is learned when the lockup clutch in the off state is started based on the learned value. By correcting with PS (correction pressure), the slip amount of the lockup clutch at the time of shifting from lockup off to on is appropriately controlled. As a result, heat generation and fuel consumption deterioration due to excessive generation of clutch slip due to the lock-up clutch command hydraulic pressure being too low, or occurrence of engagement shock due to the lock-up clutch command hydraulic pressure being too high, etc. Can be prevented. This embodiment is particularly effective when performing lock-up clutch control for quickly and tightly engaging the lock-up clutch.

  As mentioned above, although an example of embodiment was demonstrated based on drawing, this invention is not limited to this, It cannot be overemphasized that various embodiment is possible. In the embodiment described above, as shown in FIG. 3, the learning period is from the fastening start t2 to the addition control end time t4, and the next lockup is performed according to the length of the addition control time (t3 to t4) within the learning period. Although learning to increase and decrease the initial pressure at the start of clutch control has been shown, the present invention is not limited to this learning method. Such different learning methods will be described with reference to FIGS.

  FIG. 7 is a flowchart showing another embodiment of the lockup clutch command hydraulic pressure learning process. In the processing shown in FIG. 7, the processing from step S31 to S33 is the same as the processing from step S1 to S3 in FIG.

  In step S34, it is determined whether shelf pressure control is being performed. If it is determined that the shelf pressure control is being performed (YES in step S34), the average value of the accelerator pedal opening (or engine torque or throttle opening, the same applies hereinafter) is calculated (step S35). Step S36 refers to the map based on the accelerator pedal opening actually measured at that time, and calculates target slip differences D1 and D2 (where D1 <D2). The target slip differences D1 and D2 are target values for the deviation between the target slip ratio and the actual slip ratio at the end of shelf pressure control t3.

  If it is determined that the shelf pressure control is not in progress (NO in step S34), the absolute value of the difference between the calculated target slip rate and the actual slip rate, that is, the actual slip rate and the target slip rate at the shelf pressure control end time t3 It is determined whether or not the deviation (slip difference Y in the figure) is smaller than the calculated target slip difference D1 (step S37). When it is determined that the absolute value (slip difference Y) of the difference between the target slip ratio and the actual slip ratio is smaller than the calculated target slip difference D1 (YES in step S37), the stored value is stored in the learning value storage means F. The learning result is reflected by subtracting the learning value of the corresponding region based on the average accelerator pedal opening in the learning map (step S38).

  When it is determined that the absolute value (slip difference Y) of the difference between the target slip ratio and the actual slip ratio is not smaller than the calculated target slip difference D1 (NO in step S37), the target slip ratio and the actual slip ratio. It is determined whether or not the absolute value of the difference (slip difference Y) is larger than the calculated target slip difference D2 (step S39). When it is determined that the absolute value (slip difference Y) of the difference between the target slip ratio and the actual slip ratio is larger than the calculated target slip difference D2 (YES in step S39), the stored value is stored in the learning value storage means F. The learning result is reflected by adding the learning value of the corresponding region based on the average accelerator pedal opening in the learning map (step S40). When it is determined that the absolute value (slip difference Y) of the difference between the target slip ratio and the actual slip ratio is not larger than the calculated target slip difference D2 (NO in step S39), the process is terminated.

  In this embodiment, as shown in FIG. 3, the learning means A2 has a learning period from shelf pressure control start time t2 (learning start) to shelf pressure control end time t3 (learning completion), and at the end of the learning period t3. The degree of achievement of the actual slip ratio relative to the target slip ratio (that is, the deviation between the target slip ratio and the actual slip ratio) is measured, and the initial pressure at the start of the next lockup clutch control is increased or decreased according to the magnitude of the measured deviation. To learn. In this embodiment, when the deviation is small, negative learning for reducing the initial pressure is performed, and when the deviation is large, positive learning for increasing the initial pressure is performed, and these learning results (learned values) are reflected in the learning map. Is done.

  Specifically, when the deviation at the end of the shelf pressure control is smaller than a certain value, the actual slip rate and the target slip rate are substantially the same, and the clutch is excessively grasped during the shelf pressure control and in the subsequent addition control. Since it is estimated that the initial pressure is subtracted at the start of the next engagement, it is locked up so that the actual slip ratio does not approach the target slip ratio at the end of the shelf pressure control. The initial pressure at the start of clutch control is corrected appropriately so that the clutch can be properly held thereafter. On the other hand, when the deviation at the end of the shelf pressure control is larger than a certain value, the actual slip ratio and the target slip ratio are far apart, and the clutch slips greatly during the shelf pressure control and in the subsequent addition control, and heat is generated. Since it can be estimated that the easy state will continue, it is learned that the initial pressure is added at the start of the next engagement, and when the lock-up clutch control starts so that the actual slip ratio approaches the target slip ratio at the end of the shelf pressure control The initial pressure is properly corrected so that the clutch can be properly held thereafter.

  FIG. 8 is a flowchart showing still another embodiment of the lockup clutch command hydraulic pressure learning process. The processing from step S41 to S43 is the same as the processing from step S1 to S3 in FIG. In step S44, it is determined whether or not it is the timing when the lockup is turned on. If it is determined that it is the timing when the lock-up is turned on (YES in step S44), the latch slip ratio, that is, the actual slip ratio at the start of engagement is held (step S45).

  When it is determined that it is not the timing when the lock-up is turned on (NO in step S44), it is determined whether shelf pressure control is being performed (step S46). If it is determined that the shelf pressure control is being performed (YES in step S46), the average value of the accelerator pedal opening (or engine torque or throttle opening, the same applies hereinafter) is calculated (step S47). In step S48, target slip differences F1 and F2 (where F1 <F2) are calculated with reference to a map (not shown) based on the accelerator pedal opening actually measured at that time. The target slip differences F1 and F2 here are different from the target slip differences D1 and D2 calculated in step S36 of FIG. Deviation of rate.

  If it is determined that the shelf pressure control is not in progress (NO in step S46), whether or not the value obtained by subtracting the latch slip ratio from the actual slip ratio (slip difference Z in the figure) is larger than the calculated target slip difference F1. Is determined (step S49). When it is determined that the value obtained by subtracting the latch slip ratio from the actual slip ratio (slip difference Z) is larger than the calculated target slip difference F1 (YES in step S49), the learning value stored in the learning value storage means F is stored. The learning result is reflected by subtracting the learning value of the corresponding region based on the average accelerator pedal opening in the map (step S50).

  When it is determined that the value obtained by subtracting the latch slip ratio from the actual slip ratio (slip difference Z) is not larger than the calculated target slip difference F1 (NO in step S49), the latch slip ratio is subtracted from the actual slip ratio. It is determined whether the calculated value (slip difference Z) is smaller than the calculated target slip difference F2 (step S51). When it is determined that the value obtained by subtracting the latch slip ratio from the actual slip ratio (slip difference Z) is smaller than the calculated target slip difference F2 (YES in step S51), the learning value stored in the learning value storage means F is stored. The learning result is reflected by adding the learning value of the corresponding region based on the average accelerator pedal opening in the map (step S52). When it is determined that the value obtained by subtracting the latch slip ratio from the actual slip ratio (slip difference Z) is not smaller than the calculated target slip difference F2 (NO in step S51), the process is terminated.

  In the present embodiment, as shown in FIG. 3, the learning means A2 has a learning period from shelf pressure control start time t2 (learning start) to shelf pressure control end time t3 (learning completion), and the learning period (t2 to t3). The actual slip ratio deviation before and after (hereinafter simply referred to as the actual deviation) is measured, and learning is performed to increase or decrease the initial pressure at the start of the next lockup clutch control according to the measured actual deviation. In this embodiment, positive learning for increasing the initial pressure is performed when the actual deviation is small, minus learning for decreasing the initial pressure is performed when the actual deviation is large, and these learning results (learned values) are stored in the learning map. It is reflected in.

  Specifically, when comparing the actual slip ratio between the shelf pressure control start time and the end time, if the actual deviation is smaller than a certain value, the increase of the actual slip ratio is slow and the shelf pressure control is added during and after the shelf pressure control. Since it can be estimated that clutch slipping and heat generation will continue to occur during control, learning is made to add initial pressure at the start of the next engagement, and the actual slip rate is set to the target slip at the end of shelf pressure control. The initial pressure at the start of the lockup clutch control is appropriately corrected so as to approach the rate, and thereafter the clutch can be properly held. On the other hand, when the actual deviation at the end of the shelf pressure control is greater than a certain value, it can be estimated that the actual slip rate will increase rapidly and there is a high possibility that the clutch will be overgrown. Learn to subtract, correct the initial pressure at the start of lockup clutch control appropriately so that the actual slip rate does not approach the target slip rate at the end of shelf pressure control, and then To be able to hold the clutch.

  In the above-described embodiments, the engine torque and the LC transmission torque are measured. However, the present invention is not limited to this. For example, the engine torque is estimated based on the throttle opening and the engine rotation speed. An estimation method may be used.

DESCRIPTION OF SYMBOLS 1 ... Automatic transmission 2 ... Engine 3 ... Engine torque sensor 4 ... Throttle sensor 5 ... Automatic transmission mechanism 6 ... Torque converter 7 ... Lock-up clutch 8 ... Hydraulic control circuit 9 ... LC transmission torque sensor 10 ... Speed sensor 11 ... Accelerator Pedal sensor 12 ... shift sensor 13 ... other sensor 14 ... ECU
A ... Lockup clutch command oil pressure learning means A1 ... Learning start determining means A2 ... Learning means B ... Lockup clutch command oil pressure determining means C ... Target slip ratio setting means D ... Actual slip ratio detecting means E ... Lockup start determining means F ... Learning value storage means MS ... Main shaft

Claims (3)

In the lockup clutch control device for an automatic transmission that controls the engagement pressure of the lockup clutch so that the actual slip ratio of the lockup clutch of the automatic transmission becomes a predetermined target value,
Detection means for detecting engine torque or accelerator pedal opening or throttle opening;
Determination means for determining whether or not the engagement control of the lock-up clutch in the clutch-off state is started;
Learning start determination means for determining whether or not a predetermined learning start condition is satisfied when the engagement control of the lock-up clutch in the clutch-off state is started;
Learning means for learning a command hydraulic pressure that instructs an engagement pressure of the lockup clutch when the learning start condition is satisfied;
Determination to determine the original control initial command pressure that instructs the engagement pressure when starting the engagement control of the lockup clutch in the clutch-off state based on the detected engine torque, accelerator pedal opening, or throttle opening Means,
Correction means for learning and correcting the determined original control initial command pressure according to the learning result of the command oil pressure;
Control means for starting engagement control of the lock-up clutch in a clutch-off state according to the corrected control initial command pressure,
The learning means is a learning region corresponding to an engine torque or an accelerator pedal opening or an average value of a throttle opening detected until the actual slip ratio reaches within a predetermined target value or a predetermined value close to the predetermined target value from the start of the engagement control. The learning value of the command oil pressure is stored every time, and the arrival time until the actual slip rate reaches within a predetermined target value or a predetermined value close to the predetermined target value after the constant fastening pressure control is completed is measured. A lockup clutch control device for an automatic transmission, wherein the learning value is updated based on the length of the arrival time. In the lockup clutch control device for an automatic transmission that controls the engagement pressure of the lockup clutch so that the actual slip ratio of the lockup clutch of the automatic transmission becomes a predetermined target value,
Detection means for detecting engine torque or accelerator pedal opening or throttle opening;
Determination means for determining whether or not the engagement control of the lock-up clutch in the clutch-off state is started;
Learning start determination means for determining whether or not a predetermined learning start condition is satisfied when the engagement control of the lock-up clutch in the clutch-off state is started;
Learning means for learning a command hydraulic pressure that instructs an engagement pressure of the lockup clutch when the learning start condition is satisfied;
Determination to determine the original control initial command pressure that instructs the engagement pressure when starting the engagement control of the lockup clutch in the clutch-off state based on the detected engine torque, accelerator pedal opening, or throttle opening Means,
Correction means for learning and correcting the determined original control initial command pressure according to the learning result of the command oil pressure;
Control means for starting engagement control of the lock-up clutch in a clutch-off state according to the corrected control initial command pressure,
The learning means stores a learning value of the command hydraulic pressure for each learning region corresponding to an average value of engine torque, accelerator pedal opening, or throttle opening detected from the start of the engagement control to the end of constant engagement pressure control. Calculating a deviation between the actual slip rate when the constant fastening pressure control is completed and the target value when the constant fastening pressure control is completed, and updating the learning value based on the magnitude of the calculated deviation. A lockup clutch control device for an automatic transmission. In the lockup clutch control device for an automatic transmission that controls the engagement pressure of the lockup clutch so that the actual slip ratio of the lockup clutch of the automatic transmission becomes a predetermined target value,
Detection means for detecting engine torque or accelerator pedal opening or throttle opening;
Determination means for determining whether or not the engagement control of the lock-up clutch in the clutch-off state is started;
Learning start determination means for determining whether or not a predetermined learning start condition is satisfied when the engagement control of the lock-up clutch in the clutch-off state is started;
Learning means for learning a command hydraulic pressure that instructs an engagement pressure of the lockup clutch when the learning start condition is satisfied;
Determination to determine the original control initial command pressure that instructs the engagement pressure when starting the engagement control of the lockup clutch in the clutch-off state based on the detected engine torque, accelerator pedal opening, or throttle opening Means,
Correction means for learning and correcting the determined original control initial command pressure according to the learning result of the command oil pressure;
Control means for starting engagement control of the lock-up clutch in a clutch-off state according to the corrected control initial command pressure,
The learning means stores a learning value of the command hydraulic pressure for each learning region corresponding to an average value of engine torque, accelerator pedal opening, or throttle opening detected from the start of the engagement control to the end of constant engagement pressure control. The deviation between the actual slip rate at the start of the engagement control and the actual slip rate at the end of the engagement pressure constant control is calculated, and the learning value is updated based on the magnitude of the calculated deviation. Automatic transmission lock-up clutch control device.

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