JP2008121750A - Control device for lock-up clutch - Google Patents

Abstract

Even if an engagement hydraulic pressure value is difficult to perform feedback control or learning correction, it is possible to appropriately control the hydraulic pressure regardless of variations in the hydraulic characteristics of a solenoid.
A learning value GPOFS for learning correction of a release initial pressure PLU _F performed by a release initial pressure learning means 106 when releasing a lockup clutch 26 by a smooth OFF control means 104 is used as a lockup low pressure engagement means during deceleration. Since the low pressure engagement pressure P _dec of the low pressure engagement control executed by 102 is reflected, the low pressure engagement pressure P _dec can be appropriately controlled according to the hydraulic characteristics of the solenoid valve DSU actually mounted. In addition, when it is determined that the learning by the released initial pressure learning means 106 has converged to a predetermined range, the learning value GPOFS is reflected in the low pressure engagement pressure P _dec , so an error based on an unstable learning result during learning Therefore, the low pressure engagement pressure P _dec can be more appropriately controlled with high reliability.
[Selection] Figure 6

Description

  The present invention relates to a control device for a lockup clutch, and more particularly to a control device that can appropriately control the engagement hydraulic pressure regardless of variations in the hydraulic characteristics of a solenoid that controls the engagement hydraulic pressure of the lockup clutch.

One type of fluid power transmission device disposed between a power source and an automatic transmission includes a hydraulic lockup clutch that directly connects the power source side and the automatic transmission side. It is widely known to perform engagement / release control of the lockup clutch using a solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch in accordance with the hydraulic pressure command value. The device described in Patent Document 1 is an example, and by performing feedback control of the solenoid so that the lock-up clutch is in a predetermined slip state, the target slip state is achieved regardless of variations in the hydraulic characteristics of the solenoid. The engagement hydraulic pressure can be appropriately controlled. It has also been proposed to learn and correct the hydraulic pressure at the start of the feedback control based on the correction amount at the time of feedback control.
JP 2001-141050 A

  By the way, when engaging and controlling the lockup clutch during deceleration of the accelerator OFF, the lockup clutch can be quickly released, for example, when preventing engine stall due to a decrease in vehicle speed or restarting the engine due to fuel cut OFF. Therefore, it has been proposed to engage with the lowest possible hydraulic pressure. However, since it is necessary to maintain the engaged state to the last, it is difficult to feedback control or correct the learning hydraulic pressure at that time. Conventionally, it is in a slip state regardless of variations in the hydraulic characteristics of the solenoid. In order to avoid this, it was necessary to set the hydraulic pressure to a large value in consideration of the variation.

For example, in the case where there is a predetermined variation (tolerance) as shown by the broken line with respect to the hydraulic characteristic of the nominal product shown by the solid line in FIG. 10, in order to avoid slipping, a lower limit product with the lowest engagement hydraulic pressure is assumed. It is necessary to set the hydraulic pressure value. That is, if a conversion map for determining the lockup hydraulic pressure command value S _PLU based on the target value of the lockup engagement hydraulic pressure PLU is set as a solid line with reference to the nominal product, the lockup In order to engage with the combined hydraulic pressure PLU = a, the lock-up hydraulic pressure command value S _PLU = b, and the lock-up engagement hydraulic pressure PLU (target value based on the nominal product) is a variation correction pressure P _bara rather than a. A high value c is required. On the other hand, when the lock-up engagement hydraulic pressure PLU is set to a large value in this way, the actual lock-up engagement hydraulic pressure PLU becomes the hydraulic pressure c in the case of the nominal product, and becomes a higher hydraulic pressure d in the case of the upper limit product. Therefore, the hydraulic pressure is controlled to be higher than necessary. When a conversion map is set based on the hydraulic characteristics of the lower limit product, the target value itself of the lockup engagement hydraulic pressure PLU does not need to be increased, but the actual hydraulic pressure is higher than necessary for the nominal product and the upper limit product. It is the same.

  Such a problem also occurs in the control of other engagement oil pressure values in which feedback control and learning correction are difficult. In addition, not only the hydraulic characteristics of the solenoid, but also variations in the friction coefficient μ of the friction material of the lock-up clutch may be affected. In this case, the hydraulic pressure value (target value) should be set in consideration of the variation in the friction coefficient μ. Must be set.

  The present invention has been made against the background of the above circumstances, and the purpose of the present invention is appropriate regardless of variations in the hydraulic characteristics of the solenoid, even if the engagement hydraulic pressure is difficult to perform feedback control or learning correction. It is to be able to perform hydraulic control.

  In order to achieve such an object, the first invention is provided in (a) a fluid-type power transmission device disposed between a power source and an automatic transmission, and the power source side and the automatic transmission side are provided. (B) A solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch in accordance with a hydraulic pressure command value, and the engagement of the lockup clutch is controlled via the solenoid. In the control device, (c) when the engagement hydraulic pressure of the lockup clutch is controlled to a predetermined first hydraulic pressure, the first mode is such that the mode when the lockup clutch is engaged or released becomes the predetermined mode. Learning means for correcting and correcting the hydraulic pressure; (d) a convergence determining means for determining that learning by the learning means has converged to a predetermined range; and (e) that the learning has been converged to a predetermined range by the convergence determining means. If it is, and having a learning reflection means for reflecting the hydraulic control of a different second hydraulic pressure from the first hydraulic the learning result.

  According to a second aspect of the present invention, in the lockup clutch control device according to the first aspect, the learning means uses the release initial pressure during the smooth OFF control in which the engagement hydraulic pressure of the lockup clutch is smoothly lowered and released during the release time. Based on this, the initial correction pressure is the first hydraulic pressure.

  According to a third aspect of the invention, in the lockup clutch control device of the first or second aspect of the invention, (a) the learning reflecting means is a low pressure that holds the lockup clutch in an engaged state at a lower than normal low pressure engagement pressure. In the engagement control, the learning result is reflected in the low pressure engagement pressure, the low pressure engagement pressure is the second hydraulic pressure, and (b) a shift operation is performed during the execution of the low pressure engagement control. When this is detected, the low-pressure engagement pressure is corrected in consideration of the change in inertia torque associated with the shift.

  In such a lockup clutch control device, the hydraulic pressure of the second hydraulic pressure is obtained using the learning result of the learning correction performed by the learning means when the engagement hydraulic pressure of the lockup clutch is controlled to the predetermined first hydraulic pressure. Since the control is performed, even when feedback control or learning correction of the second hydraulic pressure itself is difficult, the second hydraulic pressure can be appropriately controlled according to the hydraulic characteristics of the solenoid actually used. Moreover, when it is determined that the learning by the learning means has converged to a predetermined range, the learning result is reflected in the hydraulic control of the second hydraulic pressure, thereby preventing erroneous hydraulic control based on the unstable learning result during learning. Thus, the second hydraulic pressure can be more appropriately controlled with high reliability.

  The second invention is a case where learning initial correction of release initial pressure during smooth OFF control in which the engagement hydraulic pressure of the lockup clutch is smoothly lowered and released is corrected based on the release time. By the fact that the learning result is reflected in the hydraulic control of the second hydraulic pressure, the variation in the hydraulic characteristics of the solenoid is also well absorbed in the hydraulic control of the second hydraulic pressure, The second hydraulic pressure is appropriately controlled according to the hydraulic characteristics of the solenoid actually used.

  In the third aspect of the invention, in the low pressure engagement control in which the lockup clutch is held in the engaged state at a lower pressure engagement pressure than usual, the learning result is reflected in the low pressure engagement pressure. It is possible to further reduce the low-pressure engagement pressure while reliably avoiding the slip according to the hydraulic characteristics of the engine, and the lock-up clutch can be released more quickly in response to the lock-up release command. In addition, when it is detected that a shift operation has been performed during execution of the low pressure engagement control, the low pressure engagement pressure is corrected in consideration of the change in the inertia torque associated with the shift. It is possible to further reduce the low-pressure engagement pressure other than during gear shifting while preventing the occurrence of slippage due to the change of the above.

  The control device for a lock-up clutch according to the present invention is suitably applied to lock-up control of a fluid power transmission device mounted on a vehicle. As the fluid type power transmission device, a torque converter or a fluid coupling is preferably used. As the power source, various modes such as an engine that generates power by combustion of fuel, an electric motor, or a hybrid power source including both of them are possible. As the automatic transmission, various automatic transmissions such as a stepped automatic transmission such as a planetary gear type or a two-shaft meshing type or a continuously variable transmission such as a belt type can be adopted.

  As a solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch, for example, a duty solenoid that outputs a hydraulic pressure according to the duty ratio of the excitation current is preferably used, but the hydraulic pressure according to the magnitude of the excitation current is output. It is also possible to employ a linear solenoid or the like. In general, the control valve is controlled using the output hydraulic pressure of a solenoid valve provided with a solenoid as a signal pressure to adjust the engagement hydraulic pressure of the lockup clutch.

  As the learning means, for example, the one that learns and corrects the initial release pressure during smooth OFF control based on the release time as in the second aspect of the invention is preferably used. However, the learning means is related to the slip control so as to be in a predetermined slip state. Other learning means such as one that learns and corrects the combined hydraulic pressure (first hydraulic pressure) can also be used. The smooth OFF control is a control that smoothly decreases the engagement hydraulic pressure from the initial release pressure at a constant rate of change. The release time from the start of control until the lockup clutch actually starts to rotate (slip) is the target value. By learning and correcting the initial release pressure so that they match, the lockup clutch can be quickly operated while suppressing the release shock, regardless of individual differences such as variations in the hydraulic characteristics of the solenoid and variations in the friction coefficient μ of the friction material. Can be released to. The actual first hydraulic pressure (such as the initial release pressure) may be corrected by learning, and the learning target may be related to a target value of hydraulic pressure or a hydraulic pressure command value.

  The hydraulic control of the second hydraulic pressure that reflects the learning result is particularly effective for feedback control and learning correction such as low-pressure engagement control of the third invention, but the present invention is particularly effective, but feedback control and learning correction are possible Even in the oil pressure control, the second oil pressure can be appropriately controlled regardless of variations in the oil pressure characteristics of the solenoid while simplifying the control by applying the present invention.

  In the third aspect of the invention, when a shift operation is performed during the execution of the low pressure engagement control, the low pressure engagement pressure is corrected in consideration of the change in the inertia torque associated with the shift. The hydraulic pressure correction at the time of the shift operation is not limited to the low pressure engagement control, but can be applied when the hydraulic control of the second hydraulic pressure is other than the low pressure engagement control. The shift operation includes, for example, a shift operation to a low speed range using a shift lever, a sequential shift operation to an up / down position, a paddle shift operation using a lever or a switch disposed on a steering wheel, a sequential shift operation, and the like. Further, the third aspect of the invention is a case where the shift is performed according to the shift operation, but the same hydraulic pressure correction can be performed as necessary even when the shift is automatically performed according to a predetermined shift map or the like. It is.

  When the transmission torque (input torque) of the lock-up clutch changes or the torque capacity changes, the engagement state of the lock-up clutch may change and slip may occur. When it is desired to reduce the engagement hydraulic pressure to the limit as described above, it is desirable to perform hydraulic pressure correction using a map or the like. For example, when the transmission torque of the lockup clutch changes, there is a case where the operating state of an auxiliary device such as an air conditioner or an alternator changes in addition to the above-mentioned speed change. There are cases in which the oil pressure changes or the friction coefficient μ of the friction material changes due to the oil temperature becoming higher or lower than a predetermined range. It is desirable that the same hydraulic pressure correction be performed in the hydraulic pressure control of the first hydraulic pressure in which learning correction is performed by the learning means. The largest factor related to the engagement hydraulic pressure of the lock-up clutch is related to the power source. Based on the load (torque, rotational speed change, etc.) of the power source, the second factor such as the low-pressure engagement pressure is calculated by an arithmetic expression or a map. A reference value for hydraulic pressure is established.

  Convergence determining means for determining that learning by the learning means has converged to a predetermined range, when the learning result is reflected in the hydraulic control of the second hydraulic pressure, an incorrect hydraulic pressure based on an unstable learning result during learning This is to prevent the control from being performed, and the criterion is appropriately determined according to the learning mode by the learning means, the required accuracy of the hydraulic control of the second hydraulic pressure, and the like.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a vehicle drive device 10 to which the present invention is applied. This vehicle drive device 10 is of a horizontal type and is suitably employed in an FF (front engine / front drive) type vehicle, and includes an engine 12 as a power source for traveling. The output of the engine 12 composed of an internal combustion engine is divided into a crankshaft 13 of the engine 12, a torque converter 14 as a fluid power transmission device, a forward / reverse switching device 16, an input shaft 36, a belt type continuously variable transmission (CVT). 18) is transmitted to the differential gear device 22 via the reduction gear device 20, and is distributed to the left and right drive wheels 24L, 24R. The torque converter 14, the forward / reverse switching device 16, the belt type continuously variable transmission 18 as an automatic transmission, and the like constitute a power transmission mechanism.

  The intake pipe 31 of the engine 12 is provided with an electronically controlled throttle valve 80 for electrically controlling the intake air amount of the engine 12 using a throttle actuator (not shown). The electronic control device 60 (see FIG. 2) performs the opening / closing control of the electronic control throttle valve 80, the fuel injection control, and the like according to the accelerator operation amount Acc representing the driver's requested output amount. Is controlled to increase or decrease.

  The torque converter 14 includes a pump impeller 14p connected to the crankshaft 13 of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 34. It is designed to communicate. Further, a lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and the engagement side oil chamber 15 is provided by a lockup control valve of a hydraulic control circuit 86 (see FIG. 2). When the hydraulic pressure supply to the release side oil chamber 17 is switched, the lockup clutch 26 is engaged or released, and the pump impeller 14p and the turbine impeller 14t rotate integrally by being engaged. Be made. By this engagement, the engine 12 and the belt type continuously variable transmission 18 are substantially directly connected when the power transmission path is established in the forward / reverse switching device 16. The pump impeller 14p includes a mechanical oil pump 28 that generates hydraulic pressure for controlling the shift of the belt-type continuously variable transmission 18, generating belt clamping pressure, or supplying lubricating oil to each portion. Is provided.

  The forward / reverse switching device 16 is mainly composed of a double pinion type planetary gear device, and the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16 s, and the input shaft 36 of the belt type continuously variable transmission 18. Is integrally connected to the carrier 16c, while the carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r is selectively fixed to the housing via the reverse brake B1. It is like that. The forward clutch C1 and the reverse brake B1 correspond to an interrupting device, both of which are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder. The forward clutch C1 is engaged and the reverse brake When B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state to establish (achieve) the forward power transmission path, and the forward driving force is transmitted to the belt type continuously variable transmission 18 side. The On the other hand, when the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes (achieves) the reverse power transmission path, and the input shaft 36 is connected to the turbine shaft 34. Thus, the drive force in the reverse direction is transmitted to the belt type continuously variable transmission 18 side. Further, when both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 becomes neutral (interrupted state) for interrupting power transmission.

The belt-type continuously variable transmission 18 has an input-side variable pulley 42 with a variable effective diameter that is an input-side member provided on the input shaft 36, and an effective diameter that is an output-side member provided on the output shaft 44. Output side variable pulley 46 and a transmission belt 48 wound around these variable pulleys 42, 46, and power is transmitted via a frictional force between the variable pulleys 42, 46 and the transmission belt 48. Is done. The variable pulleys 42 and 46 are fixed rotation bodies 42 a and 46 a fixed to the input shaft 36 and the output shaft 44, respectively, and are not rotatable relative to the input shaft 36 and the output shaft 44 and are movable in the axial direction. The movable rotating bodies 42b and 46b provided, and an input-side hydraulic cylinder 42c and an output-side hydraulic cylinder 46c that apply thrust for changing the V-groove width between them are configured to be variable on the input side. By controlling the hydraulic pressure of the hydraulic cylinder 42c of the pulley 42, the V groove width of both the variable pulleys 42 and 46 is changed to change the engagement diameter (effective diameter) of the transmission belt 48, and the transmission ratio γ (= input shaft). The rotational speed N _IN / output shaft rotational speed N _OUT ) is continuously changed. The hydraulic pressure of the hydraulic cylinder 46c of the output side variable pulley 46 is controlled so that the transmission belt 48 is clamped with a predetermined clamping pressure that does not cause belt slip.

FIG. 2 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 12 and the lock-up clutch 26 of the torque converter 14, the belt-type continuously variable transmission 18 and the like shown in FIG. 60 includes an engine rotation speed sensor 62, a turbine rotation speed sensor 64, an input shaft rotation speed sensor 65, a vehicle speed sensor 66, a throttle sensor 68 with an idle switch, a cooling water temperature sensor 70, a CVT oil temperature sensor 72, an accelerator operation amount sensor 74. , A foot brake switch 76, a lever position sensor 78, an air conditioner switch 92, etc. are connected, the rotational speed of the engine 12 (engine rotational speed) NE, the rotational speed of the turbine shaft 34 (turbine rotational speed) NT, and the rotational speed of the input shaft 36. (Input shaft rotation speed) N _IN , vehicle speed V, electronic throttle valve 80 fully closed State (idle state) and its opening (throttle valve opening) θ _TH , cooling water temperature T _{W of} engine 12, oil temperature T _CVT of the hydraulic circuit such as belt type continuously variable transmission 18 and lockup clutch 26, accelerator pedal Accelerator operation member operation amount (accelerator opening) Acc, presence / absence of foot brake operation, shift lever 77 lever position (operation position) P _SH , air conditioner operation signal, etc. are supplied It has come to be. The turbine speed NT is the time the forward clutch C1 is engaged forward travel matches the input shaft rotational speed N _IN, the vehicle speed V is the rotational speed (output shaft rotation of the output shaft 44 of the belt type continuously variable transmission 18 Speed) corresponds to N _OUT . The accelerator operation amount Acc represents the driver's requested output amount.

  The shift lever 77 includes a parking position “P” for parking, a reverse position “R” for reverse travel, a neutral position “N” for interrupting power transmission, a drive position “D” for forward travel, a forward travel In some cases, the gear ratio γ of the belt type continuously variable transmission 18 is selectively operated to a manual position “M” where the manual operation can be increased or decreased. The manual position “M” includes a plurality of ranges in which a plurality of shift ranges having different downshift positions and upshift positions for increasing / decreasing the gear ratio γ or different upper limits of the gear range (the side on which the gear ratio γ is smaller) can be selected. Position etc. are provided. The lever position sensor 78 is, for example, the parking position “P”, reverse position “R”, neutral position “N”, drive position “D”, manual position “M”, upshift position, downshift position, or It has a plurality of ON and OFF switches that detect that the shift lever 77 has been operated to the range position or the like. In order to change the gear ratio γ manually, a downshift switch, an upshift switch, or a lever can be provided on the steering wheel or the like separately from the shift lever 77.

  The electronic control unit 60 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM, and performs signal processing according to a program stored in the ROM in advance. By performing the processing, output control of the engine 12, shift control of the belt-type continuously variable transmission 18, belt clamping pressure control, engagement and release control of the lock-up clutch 26, and the like are executed. Depending on the situation, the engine control and the shift control are divided. The output control of the engine 12 is performed by an electronic throttle valve 80, a fuel injection device 82, an ignition device 84, etc., and the shift control of the belt type continuously variable transmission 18, the belt clamping pressure control, and the engagement and release of the lockup clutch 26. All the controls are performed by a hydraulic control circuit 86. The hydraulic control circuit 86 is a solenoid valve that opens and closes the oil passage when excited by the electronic control device 60, a linear solenoid valve that performs hydraulic control, and opens and closes the oil passage according to the signal pressure output from these solenoid valves. It includes an on-off valve, a pressure regulating valve, and the like.

With respect to the shift control of the belt type continuously variable transmission 18, the electronic control unit 60, for example, as shown in FIG. 3, is a shift map determined in advance with the accelerator operation amount Acc representing the driver's required output amount and the vehicle speed V as parameters. The target rotational speed N _IN ^* on the input side is calculated from the above, and the shift control of the continuously variable transmission 18 is performed in accordance with such deviation so that the actual input shaft rotational speed N _IN matches the target rotational speed N _IN ^*. That is, the shift control pressure P _BELT is controlled by supplying and discharging the hydraulic oil to and from the hydraulic cylinder 42c of the input side variable pulley 42, and the speed ratio γ is continuously changed. The map in FIG. 3 corresponds to the shift condition, and the target rotational speed N _IN ^* is set such that the larger the vehicle speed V is and the accelerator operation amount Acc is, the larger the gear ratio γ is. Further, since the vehicle speed V corresponds to the output shaft rotational speed N _OUT , the target rotational speed N _IN ^*, which is the target value of the input shaft rotational speed N _IN , corresponds to the target speed ratio, and the minimum speed ratio of the continuously variable transmission 18. It is determined within the range of γmin and maximum gear ratio γmax.

For example, as shown in FIG. 4, the basic control for engaging and releasing the lock-up clutch 26 is based on a switching map (switching conditions) stored in advance using the throttle valve opening θ _TH corresponding to the input torque and the vehicle speed V as parameters. Then, ON (engaged) -OFF (released) is switched according to the actual throttle valve opening degree θ _TH and the vehicle speed V. In the switching map, an engagement switching line indicated by a solid line and a disengagement switching line indicated by a broken line are determined with a predetermined hysteresis, and the vehicle speed V crosses the engagement switching line in a disengaged state of the lockup clutch. When the throttle valve opening degree θ _TH changes to the low throttle valve opening degree side across the engagement switching line, the lockup clutch 26 is engaged. Further, when the vehicle speed V changes to the low vehicle speed side across the release switching line while the lockup clutch is engaged, or the throttle valve opening θ _TH changes across the release switching line to the high throttle valve opening side, The up clutch 26 is released.

Also, during deceleration traveling, that is, during forward traveling where the accelerator pedal is not depressed and the inertia is turned off, the reverse input from the drive wheel side is directly transmitted to the engine 12 side by engaging the lock-up clutch 26. Thus, the fuel cut region (vehicle speed range) in which the fuel supply to the engine 12 is stopped is expanded by gradually decreasing the engine speed NE according to the deceleration of the vehicle. In order to improve fuel efficiency, the engine 12 is controlled so as to perform fuel cut control for stopping fuel supply by the fuel injection device 82 at a predetermined vehicle speed or higher when the vehicle is decelerated in an idle state where the throttle valve opening θ _TH is zero. It has become.

  FIG. 5 is a circuit diagram showing a lockup control circuit 200 for controlling the engagement and release of the lockup clutch 26 in the hydraulic control circuit 86, and includes a lockup control valve 202. The lockup control valve 202 is connected to the pair of first line pressure port 204 and second line pressure port 206 to which the line pressure PL2 is supplied from the second pressure regulating valve, and to the engagement side oil chamber 15 of the torque converter 14. The joint side port 208, the release side port 210 connected to the release side oil chamber 17 of the torque converter 14, and the signal pressure port 212 to which the engagement signal pressure PDSU output from the lockup engagement pressure control solenoid valve DSU is supplied. It has. When the engagement signal pressure PDSU is supplied to the signal pressure port 212, the spool 214 is turned downward against the urging force of the spring 216 as shown in the right half of the center line. The first line pressure port 204 and the engagement side port 208 are connected to each other, the lockup engagement hydraulic pressure PLU is supplied to the engagement side oil chamber 15, and the release side port 210 is connected to the drain port 218. Thus, the hydraulic oil in the release side oil chamber 17 is drained, and the lockup clutch 26 is engaged (ON).

The lock-up engagement pressure control solenoid valve DSU stops output of the engagement signal pressure PDSU when OFF (non-excitation), but is output from the electronic control unit 60 in the excitation state where the engagement signal pressure PDSU is output. that by the exciting current is duty controlled according to the lock-up hydraulic pressure command value S _PLU, continuously changing the engagement signal pressure PDSU. The lock-up control valve 202 includes a feedback oil chamber 220 to which a lock-up engagement hydraulic pressure PLU is supplied. The spool 214 is moved so that the lock-up engagement hydraulic pressure PLU is balanced with the engagement signal pressure PDSU. It is done. Thus, it is possible to continuously control the lock-up engagement hydraulic pressure PLU in response to the engagement signal pressure PDSU i.e. lockup hydraulic pressure command value S _PLU, the lock-up clutch 26 in accordance with the lock-up engagement hydraulic pressure PLU The engagement torque, that is, the engagement force is continuously changed. In this embodiment, the solenoid of the solenoid valve DSU for lockup engagement pressure control is a solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch 26 (corresponding to the lockup engagement hydraulic pressure PLU).

  On the other hand, when the lock-up engagement pressure control solenoid valve DSU is turned off (de-energized) and the output of the engagement signal pressure PDSU is stopped, the lock-up control valve 202 springs as shown in the left half of the center line. The spool 214 is moved upward in accordance with the urging force of 216 to be in an OFF state in which it is held at the original position. Thereby, the second line pressure port 206 and the release side port 210 are communicated, the line pressure PL2 is supplied to the release side oil chamber 17, and the engagement side port 208 is communicated to the discharge port 222. The hydraulic oil in the engagement side oil chamber 15 is discharged from the discharge port 222, and the lockup clutch 26 is released (OFF). The hydraulic oil discharged from the discharge port 222 is returned to the oil pan or the like through the oil cooler 224, and the hydraulic oil is cooled by the oil cooler 224. Excess hydraulic oil is returned from the cooler bypass valve 226 to an oil pan or the like.

  The lockup control valve 202 is also provided with a backup port 228 to which the output hydraulic pressure PSL of the lockup solenoid valve SL is supplied. When the output hydraulic pressure PSL is supplied, the lockup control valve 202 supplies the engagement signal pressure PDSU. Regardless, the lockup control valve 202 is maintained in the OFF state, and the lockup clutch 26 is forcibly released. The lock-up solenoid valve SL is an ON-OFF solenoid valve that outputs the line pressure PL as the output hydraulic pressure PSL as it is. For example, by outputting the hydraulic pressure PSL at a low vehicle speed such as when the vehicle is stopped, the lock-up engagement pressure It is possible to prevent the engine stall due to the lock-up clutch 26 being engaged by an ON failure of the control solenoid valve DSU.

FIG. 6 is a functional block diagram for explaining the control function of the electronic control unit 60 with respect to the engagement release control of the lockup clutch 26. The lockup clutch 26 is engaged and released according to the switching map of FIG. The lockup clutch control means 100 that executes basic control further includes a deceleration lockup low pressure engagement means 102 and a smooth OFF control means 104. The lockup low-pressure engagement means 102 during deceleration prevents engine stall due to a decrease in vehicle speed or restarts the engine 12 when the fuel cut is turned off when the lockup clutch 26 is engaged and controlled during deceleration of the accelerator OFF. At this time, the lockup clutch 26 is engaged with a low pressure engagement pressure P _dec lower than a normal lockup engagement pressure such as when the accelerator is ON, so that the lockup clutch 26 can be quickly released. In the graph of the lockup engagement hydraulic pressure PLU in FIG. 8, the hydraulic pressure PLU _ON indicated by a solid line at the time of lockup engagement before the release command time t _S is a normal engagement pressure when the accelerator is _{ON, and} is a low pressure indicated by a one-dot chain line. The engagement pressure P _dec is set to a hydraulic pressure lower than the normal engagement pressure PLU _ON within a range where no slip occurs.

The smooth OFF control means 104 releases the lockup clutch 26 as quickly as possible while suppressing the release shock, and performs signal processing according to the flowchart of FIG. In step SB1 in FIG. 7, it is determined whether running lockup ON control to engage with the lock-up clutch 26 the normal engagement pressure PLU _ON or low pressure engagement pressure P _dec, as if running When the lock-up ON control is being executed, step SB2 and the subsequent steps are executed. In step SB2, it is determined whether or not a release command for releasing the lockup clutch 26 is output in accordance with the switching map of FIG. 4 or other release conditions. Execute OFF control. FIG. 8 is an example of a time chart when this smooth OFF control is performed. At time t _S , the release command is output, the determination of step SB2 becomes YES (positive), and the smooth OFF control is started. It's time.

In step SB3, a release initial pressure PLU _F which is an initial hydraulic pressure for smooth OFF control is set. As is apparent from FIG. 8, the smooth OFF control is a method for smoothly lowering the lockup engagement hydraulic pressure PLU from the initial release pressure PLU _F to the release hydraulic pressure PLU _OFF at a predetermined constant change rate. In this control, the clutch 26 is released smoothly. Therefore, in order to quickly release the lockup clutch 26, it is desirable to set the release initial pressure PLU _F to the lowest possible hydraulic pressure within a range in which the lockup clutch 26 does not slip. Basically, FIG. A release initial pressure reference value is obtained according to the engine speed NE according to a map as shown in FIG. This is the case when the accelerator is OFF, and the reference value may be obtained based on the engine load such as the throttle valve opening θ _TH when the accelerator is ON. In addition, the required clutch torque changes depending on the load of auxiliary equipment such as air conditioners and alternators, and the viscosity resistance and the response to changes in hydraulic pressure also change when the CVT oil temperature T _CVT is higher or lower than the specified range. to change the clutch torque and, for example, in FIG. 9 (b), the correction values are calculated for it, such as in accordance with a map as shown in (c), disengagement initial pressure PLU _F is added to the disengagement initial pressure reference value Ask. Furthermore, the release initial pressure PLU _F may be set in consideration of other factors that affect the transmission torque of the lockup clutch 26, such as the rate of change of the engine speed NE.

On the other hand, the hydraulic characteristic of the lockup engagement pressure control solenoid valve DSU for controlling the lockup engagement hydraulic pressure PLU, that is, the relationship between the lockup hydraulic pressure command value _SPLU and the lockup engagement hydraulic pressure PLU is shown in FIG. There is variation (tolerance) as shown by the broken line with respect to the hydraulic characteristics of the nominal product indicated by the solid line. Further, as a conversion map for calculating the lock-up hydraulic pressure command value S _PLU based on the target value of the lock-up engagement hydraulic pressure PLU, in this embodiment, a map as shown by a solid line is set based on the nominal product. The lockup hydraulic pressure command value S _PLU is calculated according to the target value of the lockup engagement hydraulic pressure PLU according to the conversion map. Therefore, for example, in the case of the lockup engagement pressure control solenoid valve DSU whose hydraulic characteristic is the lower limit product, when the lockup engagement hydraulic pressure PLU (target value based on the nominal product) is c, the lockup hydraulic pressure command value S _{Although PLU} = b, the actual lockup engagement hydraulic pressure PLU is a lower than c, and the lockup engagement hydraulic pressure PLU may be insufficient.

In order to absorb such variations in hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU or other variations in hydraulic control due to individual differences, the release initial pressure learning means 106 (see FIG. 6) is used in this embodiment. The release initial pressure PLU _F is successively learned and corrected. The release initial pressure learning means 106 calculates the learning value GPOFS according to the flowchart of FIG. 11 and stores it overwritten in the learning value storage device 108. The smooth OFF control means 104 performs the release initial pressure PLU _{F in} step SB3. when setting, it corrects the disengagement initial pressure PLU _F from the learning value storage unit 108 reads the learned value GPOFS.

In step SC1 of FIG. 11, each time smooth OFF control is performed, it is determined whether or not learning control of the release initial pressure PLU _F is possible. If learning control is possible, step SC2 and subsequent steps are executed. This learning control permission criterion is determined based on whether or not the learning control can be performed appropriately. For example, when the sensor is abnormal, the engine cooling water temperature _TW is equal to or lower than a predetermined value, and manual shifting by operating the shift lever is performed. During execution, learning control is not permitted when the vehicle suddenly stops. If the oil pressure correction by the auxiliary machine load or the oil pressure correction by the CVT oil temperature T _CVT is not performed, the learning control is not permitted even when the auxiliary machine load or the CVT oil temperature T _CVT is out of the predetermined range. Is desirable.

In step SC2, the actual release time JKAIHOU at the time of smooth OFF control is read. The release time JKAIHOU is the time from the time t _S when the smooth OFF control is started by the release command as shown in FIG. 8 to the lock-up OFF time t _R where the lock-up clutch 26 actually starts relative rotation (slip). Whether or not the lockup is OFF can be determined based on whether or not there is a difference between the engine rotational speed NE and the turbine rotational speed NT. In the next step SC3, it is determined whether or not the release time JKAIHOU is within a predetermined allowable range determined based on the target release time MKAIHOU. If it is within the allowable range, the current learning value GPOFS is maintained as it is in step SC4. To do. If the deviation is outside the allowable range, the learning value GPOFS is increased or decreased in step SC5 according to the deviation, and the corrected new learning value GPOFS is overwritten in the learning value storage device 108. If the learning value GPOFS is 0 and the lockup engagement pressure control solenoid valve DSU is nominal, the learning value GPOFS is maintained at approximately 0, but if it is the lower limit, the release initial pressure PLU is maintained. _The positive learning value GPOFS is set so as to increase _F (target value), and in the case of the upper limit product, the negative learning value GPOFS is set so as to decrease the release initial pressure PLU _F (target value).

When the release initial pressure PLU _F is set using the learned value GPOFS in step SB3 of FIG. 7, in step SB4, the lockup engagement hydraulic pressure PLU is reduced to the release initial pressure PLU _F at once, and The pressure is smoothly lowered from the initial release pressure PLU _F to the release hydraulic pressure PLU _OFF at a predetermined constant change rate. Specifically, the lock-up engagement oil pressure PLU in FIG. 8 is a target value (command oil pressure), and the lock-up oil pressure command value S is determined according to the lock-up engagement oil pressure PLU according to the conversion map indicated by the solid line in FIG. _PLU is sequentially calculated, and the excitation current of the lockup engagement pressure control solenoid valve DSU is duty controlled in accordance with the lockup hydraulic pressure command value _SPLU . In this case, disengagement initial pressure for PLU _F is learning correction in accordance with the release time JKAIHOU, released in response to actual hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU mounted initial pressure PLU _F Is controlled to an appropriate hydraulic pressure value, and the smooth OFF control is appropriately performed so that the actual release time JKAIHOU becomes the target release time MKAIHOU. The time t _{E in} FIG. 8 is the end time of the smooth OFF control, and the lockup clutch 26 is released at the lockup OFF time t _R before that. In this embodiment, the release initial pressure PLU _F corresponds to the first hydraulic pressure.

Incidentally, the deceleration time of lock-up low-pressure engagement control by the deceleration lock-up low-pressure engagement means 102, it is desirable to learn correct low engagement pressure P _dec as above disengagement initial pressure PLU _F, when the deceleration In lock-up low-pressure engagement control, it is necessary to reliably maintain the lock-up clutch 26 in an engaged state, so that it is difficult to feedback-control or correct learning of the low-pressure engagement pressure P _dec . For this reason, conventionally, the low pressure engagement pressure P _dec is taken into consideration so that the slip state does not occur regardless of variations (individual differences) in the hydraulic characteristics of the lockup engagement pressure control solenoid valve DSU. Was set large. That is, for the lockup engagement pressure control solenoid valve DSU, the low pressure engagement pressure P _dec is set to a hydraulic pressure that is higher by the variation correction pressure P _bara assuming the lower limit product in FIG. Therefore, actually, if the lock-up engagement pressure control solenoid valve DSU that is equipped with a lower limit product variation correction pressure P _bara higher by the low-pressure engagement pressure deceleration lock-up low-pressure engagement control at P _dec is performed As a result, the engagement pressure of the lockup clutch 26 is appropriately controlled. However, in the case of nominal products, the actual low pressure engagement pressure P _dec is higher than the expected value by the dispersion correction pressure P _bara , and in the case of upper limit products, the pressure is higher and is higher than necessary. There was a problem of being controlled by hydraulic pressure.

On the other hand, in this embodiment, as shown in FIG. 6, a convergence determining unit 110 and a learning reflecting unit 112 are provided, and the learning result of the learning control by the release initial pressure learning unit 106 is changed to the lockup low pressure engagement control during deceleration. The minimum required low-pressure engagement pressure P _dec is set according to the hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU actually used and used. That is, the learned value GPOFS of the release initial pressure PLU _F reflects the hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU that is actually mounted, so that instead of the variation correction pressure P _bara By reflecting the learned value GPOFS in the low pressure engagement pressure P _dec , the low pressure engagement pressure P _dec can be further reduced while avoiding the lockup clutch 26 from being slipped. In this embodiment, this low pressure engagement pressure P _dec corresponds to the second hydraulic pressure.

FIG. 12 is a flowchart for explaining signal processing when the lockup low-pressure engagement control at the time of deceleration is executed using the learning value GPOFS of the release initial pressure PLU _F as described above. Steps SA1 to SA5 are convergence determination means 110. Step SA7 corresponds to the learning reflection means 112, and the other steps SA6, SA8 to SA12 correspond to the deceleration lockup low-pressure engagement means 102.

In step SA1 of FIG. 12, it is determined whether the actual release time or JKAIHOU is shorter than the counter clear determination time T _CLR predetermined, but executes directly step SA3 follows if JKAIHOU ≧ T _CLR, JKAIHOU < in the case of T _CLR performs step SA3 follows after a 0 to clear the learning counter CNT at step SA2. Counter clear determination time T _CLR, such as when the lock-up engagement pressure control solenoid valve DSU is lower goods, if the actual lock-up engagement hydraulic pressure PLU is lower than nominal products, disengagement initial pressure PLU _F Most learning This is for determining whether or not the lockup clutch 26 is released in a very short time without being corrected, and a relatively short fixed time is set as shown in FIG.

At step SA3, it is determined whether the actual release time JKAIHOU is counter-up determination time T _UP or more predetermined, but executes directly step SA5 follows if JKAIHOU <T _UP, if the JKAIHOU ≧ T _UP In step SA4, 1 is added to the learning counter CNT, and then step SA5 and subsequent steps are executed. The counter-up determination time T _UP is a learning correction of the release initial pressure PLU _F when the actual lock-up engagement hydraulic pressure PLU is lower than the nominal product, such as when the lock-up engagement pressure control solenoid valve DSU is a lower limit product. Is progressed to some extent, and it is determined whether or not the learning value GPOFS can be diverted to the lockup low pressure engagement control during deceleration. As shown in FIG. 8, the target release time MKAIHOU A certain short time is set.

In step SA5, it is determined whether or not the learning counter CNT has become larger than a predetermined convergence determination value C _OK. If CNT ≦ C _OK , that is, the learning correction of the release initial pressure PLU _F has not yet converged. In this case, in step SA6, the low pressure engagement pressure P _dec is set according to the following equation (1). On the other hand, if CNT> C _OK , that is, if the learning correction of the release initial pressure PLU _F has converged to some extent, step SA7 Then, the learning value GPOFS of the release initial pressure PLU _F is read from the learning value storage device 108 and the low pressure engagement pressure P _dec is set according to the following equation (2). The convergence determination value C _OK is used to determine whether or not the learning correction of the release initial pressure PLU _F has converged to some extent and the learning value GPOFS is substantially stabilized. In this case, a predetermined value (for example, about 5 to 10) is set in advance in consideration of the number of learnings until the actual release time JKAIHOU reaches the vicinity of the target release time MKAIHOU.
P _dec = P _Eng + P _AUX + P _bara (1)
P _dec = P _Eng + P _AUX + GPOFS (2)

“P _Eng ” in the above equations (1) and (2) is a low-pressure engagement reference value, and is calculated according to the engine speed NE according to a map as shown in FIG. In this case, in order to surely avoid the slip of the lockup clutch 26, a value higher than the release initial pressure reference value shown in FIG. “P _AUX ” is a hydraulic pressure correction value according to the operating state of auxiliary loads such as an air conditioner and an alternator, and is calculated according to the auxiliary load according to a map as shown in FIG. For example, the same map as that shown in FIG. 9B can be used as the map shown in FIG. In the equation (1) when the learning correction of the release initial pressure PLU _F has not yet converged, the low-pressure engagement pressure P _dec is calculated by adding a predetermined variation correction pressure P _bara as in the conventional case. However, in the expression (2) when the learning correction of the release initial pressure PLU _F converges, the low pressure engagement pressure P _dec is calculated by adding the learning value GPOFS of the release initial pressure PLU _F instead of the variation correction pressure P _bara. To do. FIG. 13 is a diagram for explaining the difference between the expressions (1) and (2). The left side is the expression (1) and the right side is the expression (2), and the learning value GPOFS is used instead of the variation correction pressure P _bara. The low-pressure engagement pressure P _dec on the right side (equation (2)) decreases by the amount.

FIG. 15 shows the time when the determination in step SA5 is YES (positive) and the low pressure engagement pressure _Pdec is calculated according to the equation (2) in step SA7 and the lockup low pressure engagement control during deceleration is performed. In an example of the chart, time t ₁ is the time when the accelerator is OFF and the lockup low pressure engagement control at the time of deceleration is started. The low pressure engagement pressure P _dec is changed by adding the learning value GPOFS to the low pressure engagement reference value P _Eng and is basically changed in accordance with the change in the engine rotational speed NE. During time t _{1 to} t _4, the hydraulic pressure correction value P _AUX due to the auxiliary load is further increased.

Returning to FIG. 12, in the next step SA8, it is determined whether or not the manual shift performed in accordance with the shift operation by the shift lever 77 is performed, and whether or not CNT> C _OK , and if negative (NO). Step SA10 and subsequent steps are immediately executed. If the determination is affirmative (YES), the hydraulic pressure correction value P _mnl at the time of manual shift is further _increased in Step SA9 according to a predetermined map as shown in FIG. to add. That is, during manual shift, the load on the lock-up clutch 26 increases due to inertia torque or the like due to a sudden change in the engine speed NE. Therefore, it is necessary to further increase the low-pressure engagement pressure P _dec in consideration of the change in the inertia torque. There is. The map of FIG. 14 (c) is set for each type of shift that represents upshift or downshift, or from which shift range to which shift range. During the time t _{2 to} t _{3 in} FIG. 15, the low pressure engagement pressure P _dec is increased by the hydraulic pressure correction value P _mnl during the manual shift during the manual shift. In this embodiment, it is a requirement that CNT> C _OK, that is, the low pressure engagement pressure P _dec is calculated according to the equation (2) using the learned value GPOFS, but CNT ≦ C _OK When the low pressure engagement pressure P _dec is calculated according to the above equation (1) using the variation correction pressure P _bara , the low pressure engagement pressure P _dec is corrected with the hydraulic pressure correction value P _mnl at the time of manual shift. Also good.

In step SA10, it is determined whether or not the CVT oil temperature T _CVT is within a predetermined range. If the CVT oil temperature T _CVT is within the predetermined range, step SA12 is executed immediately, but if it deviates from the predetermined range, step SA11 is executed. Then, for example, the hydraulic pressure correction value P _tcvt obtained according to the CVT oil temperature T _CVT is further added according to a predetermined map as shown in FIG. That is, when the CVT oil temperature T _CVT increases, the viscous resistance decreases and the hydraulic pressure does not increase. Therefore, the low pressure engagement pressure P _dec is corrected to the low pressure side, while when the CVT oil temperature T _CVT decreases, the viscous resistance increases. Since the oil pressure decreases, the low pressure engagement pressure P _dec is corrected to the high pressure side. The map shown in FIG. 14 (d) can be the same map as that shown in FIG. 9 (c), for example. Each map shown in FIGS. 9 and 14 is merely an example, and is appropriately determined according to an actual input torque change, a torque capacity change of the lockup clutch 26, and the like.

Then, in the last step SA12, to calculate the lockup pressure command value S _PLU accordance conversion map shown by the solid line in FIG. 10 a low-pressure engagement pressure P _dec as the target hydraulic pressure, the lockup in accordance with the lock-up hydraulic pressure command value S _PLU The excitation current of the engagement pressure control solenoid valve DSU is duty controlled. In this case, after the learning value GPOFS of the release initial pressure PLU _F has converged, the low pressure engagement pressure P _dec is calculated using the learning value GPOFS instead of the variation correction pressure P _bara , so that it is actually mounted. The low pressure engagement pressure P _dec is further reduced in accordance with the hydraulic characteristics of the lockup engagement pressure control solenoid valve DSU.

As described above, in the lockup clutch control device of the present embodiment, the learning correction of the release initial pressure PLU _F performed by the release initial pressure learning means 106 when releasing the lockup clutch 26 by the smooth OFF control means 104 is performed. Since the learning result (learned value GPOFS) is reflected in the low pressure engagement pressure P _dec of the deceleration lockup low pressure engagement control executed by the deceleration lockup low pressure engagement means 102, feedback control and learning correction are difficult. The low-pressure engagement pressure P _dec can be appropriately controlled according to the hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU actually mounted. In addition, when it is determined that the learning by the release initial pressure learning means 106 has converged to a predetermined range, that is, when the determination in step SA5 is YES (positive), the learned value GPOFS is set to the lockup low pressure engagement during deceleration. Since this is reflected in the control, erroneous hydraulic control based on an unstable learning result during learning is prevented, and the low pressure engagement pressure P _dec can be more appropriately controlled with high reliability.

Further, in this embodiment, the lockup engagement is performed because the release initial pressure PLU _F at the time of smooth OFF control for smoothly reducing and releasing the engagement hydraulic pressure PLU of the lockup clutch 26 is corrected based on the release time JKAIHOU. Variations in the hydraulic characteristics of the pressure control solenoid valve DSU can be satisfactorily absorbed by learning correction, and the learning results are reflected in the low-pressure engagement control during deceleration. Even in the low-pressure engagement control, variations in the hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU are well absorbed, and the hydraulic characteristics of the lock-up engagement pressure control solenoid valve DSU that is actually mounted Accordingly, the low pressure engagement pressure P _dec is appropriately controlled.

Further, in this embodiment, the deceleration lock-up low-pressure engagement control to maintain the lockup clutch 26 to the engaged state in the normal engagement pressure PLU low low engagement pressure P _dec than _ON, initial release during smooth OFF control In order to reflect the learning result of the pressure PLU _{F in} the low pressure engagement pressure P _dec , the low pressure while avoiding slipping reliably according to the hydraulic characteristics of the lockup engagement pressure control solenoid valve DSU actually mounted. The engagement pressure P _dec can be further reduced, and the lockup clutch 26 can be released more quickly in response to the lockup release command. In addition, when a shift operation is performed during the execution of the lockup low-pressure engagement control during deceleration and a manual shift is performed, the low-pressure engagement pressure P _dec is set in consideration of the change in inertia torque associated with the shift. In order to correct, it is possible to further reduce the low-pressure engagement pressure P _dec other than during the shift while preventing the occurrence of slip due to a change in the inertia torque during the shift.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention is implemented in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.

1 is a skeleton diagram of a vehicle drive device equipped with a lockup clutch control device of the present invention. It is a block diagram explaining the control system of the vehicle drive device of FIG. It is a figure which shows an example of the shift map used when calculating | requiring a target rotational speed in the shift control of a belt-type continuously variable transmission. It is a figure which shows an example of the lockup switching map used when controlling the operating state of a lockup clutch. It is a principal part of the hydraulic control circuit with which the vehicle drive device of FIG. 1 is equipped, Comprising: It is a figure which shows an example of the lockup control part as a hydraulic circuit part regarding control of a lockup clutch. It is a block diagram explaining the function regarding the low pressure engagement control of the lockup clutch at the time of vehicle deceleration driving | running | working with which the electronic control apparatus of FIG. 7 is a flowchart for specifically explaining the processing contents by the smooth OFF control means of FIG. 6. It is an example of the time chart which shows the change of the rotational speed of each part and lockup engagement hydraulic pressure PLU when smooth OFF control is performed according to the flowchart of FIG. It is a figure which shows an example of the data map used when setting release initial pressure PLU _F by step SB3 of FIG. FIG. 6 is a diagram for explaining a variation in hydraulic characteristics of the lockup engagement pressure control solenoid valve DSU of FIG. 5. 7 is a flowchart for specifically explaining the processing contents by the release initial pressure learning means of FIG. 6. It is a flowchart explaining the processing content by the lockup low pressure engagement means at the time of deceleration of FIG. 6 together with the processing content by the convergence determination means and the learning reflection means. FIG. 13 is a diagram illustrating a comparison between low pressure engagement pressures P _dec calculated in steps SA6 and SA7 in FIG. In accordance with the flowchart of FIG. 12 is a diagram showing an example of a data map used in setting the low-pressure engagement pressure P _dec. It is an example of the time chart which shows the change of each part when the low pressure engagement pressure _Pdec is controlled according to the flowchart of FIG.

Explanation of symbols

12: Engine (power source) 14: Torque converter (fluid power transmission device) 18: Belt type continuously variable transmission (automatic transmission) 26: Lock-up clutch 60: Electronic control device 100: Lock-up clutch control means 102: Lock-up low pressure engagement means during deceleration 104: Smooth OFF control means 106: Release initial pressure learning means (learning means) 110: Convergence determining means 112: Learning reflection means DSU: Solenoid valve for controlling lockup engagement pressure (solenoid) PLU : Lock-up engagement hydraulic pressure (engagement hydraulic pressure) S _PLU : Lock-up hydraulic pressure command value (hydraulic pressure command value) PLU _F : Release initial pressure (first hydraulic pressure) P _dec : Low-pressure engagement pressure (second hydraulic pressure) JKAIHOU: Release Time GPOFS: Learning value

Claims (3)

A hydraulic lockup clutch that is provided in a fluid power transmission device disposed between a power source and an automatic transmission and directly connects the power source side and the automatic transmission side,
In a control device having a solenoid that continuously changes the engagement hydraulic pressure of the lockup clutch according to a hydraulic pressure command value, and controlling the engagement release of the lockup clutch via the solenoid,
Learning means for learning and correcting the first hydraulic pressure so that the engagement or release mode of the lockup clutch becomes a predetermined mode when the engagement hydraulic pressure of the lockup clutch is controlled to the predetermined first hydraulic pressure. When,
Convergence determining means for determining that learning by the learning means has converged to a predetermined range;
Learning reflecting means for reflecting the learning result in the hydraulic control of the second hydraulic pressure different from the first hydraulic pressure when the convergence determining means determines that the learning has converged to a predetermined range;
A control device for a lock-up clutch comprising: The learning means learns and corrects a release initial pressure during smooth OFF control for smoothly releasing and releasing the engagement hydraulic pressure of the lockup clutch based on a release time, and the release initial pressure is the first hydraulic pressure. The control device for a lockup clutch according to claim 1, wherein: The learning reflecting means reflects the learning result in the low-pressure engagement pressure in the low-pressure engagement control in which the lock-up clutch is held in an engaged state with a lower-pressure engagement pressure lower than normal. The pressure is the second hydraulic pressure;
The low pressure engagement pressure is corrected in consideration of a change in inertia torque associated with a shift when it is detected that a shift operation has been performed during execution of the low pressure engagement control. 3. The lockup clutch control device according to 1 or 2.

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