JP5593908B2 - Control device for lock-up clutch - Google Patents

Description

  The present invention relates to a control device for a lock-up clutch mounted on a vehicle.

  There is known a vehicle having a torque converter with a lock-up clutch between an engine and an automatic transmission and transmitting the output torque of the engine to the input shaft of the automatic transmission via the torque converter. This torque converter transmits power via fluid such as hydraulic oil between a pump impeller connected to the engine and a turbine impeller connected to an input shaft of the automatic transmission, and releases the lockup clutch. By controlling the differential pressure (lockup differential pressure) between the oil pressure in the oil chamber and the oil pressure in the engagement side oil chamber, the lockup clutch is brought into a fully engaged state, a slip state, or a released state.

  It is desirable to switch the lock-up clutch from the released state to the slip state or the fully engaged state quickly and without causing an engagement shock. Therefore, first, the lockup differential pressure is rapidly increased so that the lockup clutch is immediately brought into a state immediately before engagement, and then the lockup differential pressure is gradually increased to obtain the torque converter slip amount as the target slip amount. It is generally performed to control.

  The lock-up differential pressure that brings the lock-up clutch into a state immediately before engagement is realized by setting a command value for a hydraulic control circuit (solenoid valve) that controls the lock-up differential pressure to a specific command value. Since such command values vary due to individual differences in the lockup clutch and its hydraulic control circuit, changes with time, etc., it is necessary to learn the command values in order to correct deviation due to the variations.

  In the conventional lock-up clutch control device, the command value is learned by, for example, a hydraulic control circuit that controls the lock-up differential pressure by setting the shift range to the travel range (D range) and the vehicle speed to 10 km / h or higher. This is done by changing the command value for (solenoid valve) and detecting the timing immediately before the lockup clutch is engaged based on the change in the slip rotation speed of the torque converter at that time, and learning the command value at that timing Was value.

  In such a learning method, disturbances such as an unstable operation of the driver and a change in the running road surface state during the execution of learning control cannot be excluded. Therefore, the obtained learning value may include some errors, but in general, the lockup clutch is operated only when the vehicle speed is high (for example, when the vehicle speed is 10 km / h or more). In general, since the gear stage has shifted to the second speed stage (in the case of a continuously variable transmission, the gear ratio corresponding to the second speed stage) or the like, the learning value includes some errors. However, the engagement shock of the lock-up clutch did not become so large as to be a problem.

  By the way, Patent Documents 1 and 2 propose a technique for performing start control (hereinafter also referred to as “flex start control”) that includes a torque converter with a lock-up clutch and starts the vehicle with the lock-up clutch slipped. Has been. Also in this flex start control, it is desired to switch the lock-up clutch from the released state to the slip state quickly and without causing an engagement shock. For this reason, it is necessary to quickly set a command value for the hydraulic control circuit (solenoid valve) so that the lockup clutch is quickly brought into the state immediately before engagement from the released state even at the start of flex start control. Also in flex start control, the command value that causes the lock-up clutch to be in a state immediately before engagement varies due to individual differences in the lock-up clutch and its hydraulic control circuit, changes over time, etc., so corrections due to variations are corrected. Therefore, it is necessary to learn the command value.

JP 2005-16563 A JP 2005-3193 A

  By the way, in the flex start control, since the lockup clutch shifts from the released state to the state just before the engagement when the vehicle speed is close to zero, it is adopted as a command value for setting the lockup clutch just before the engagement. When the learning value includes an error, there is a concern that the engagement shock of the lockup clutch is increased.

  However, in the conventional learning control, disturbance during learning cannot be completely eliminated, and it is difficult to obtain a learning value with a small error.

  The present invention was devised in view of the problems described above, and controls a lock-up clutch that makes it possible to learn a command value for putting the lock-up clutch in a state immediately before engagement in a state with little disturbance. An object is to provide an apparatus.

  As means for solving the above-described problems, the lockup clutch control device of the present invention is configured as follows.

That is , the lockup clutch control device of the present invention controls the differential pressure of the lockup clutch when the shift range is the travel range, the automatic transmission is not in the neutral state, and the vehicle speed is zero. The command value changing means for changing the command value, the engine speed detecting means for detecting the engine speed, and the lockup clutch from the released state to the slip state based on the change in the engine speed with respect to the changing command value. detects the command value when moving, the learning means the lock-up clutch based on the command value learning a command value to the state immediately before the engagement, Ru comprising a.

According to the lockup clutch control device having such a configuration, the shift range is the travel range , the automatic transmission is not in the neutral state, and the vehicle speed is zero, that is, the engine speed is locked up. A learning value that is suitable for learning a command value that causes the lockup clutch to be in a state immediately before engagement based on a change in the engine speed while being relatively less susceptible to influences (disturbances) other than the engagement operation of the clutch. Can be obtained.

  In the lockup clutch control device of the present invention having the above-described configuration, the command value changing means moves the command value from the side where the lockup clutch is released to the side where it is engaged. The learning means is configured such that when the command value is changed stepwise by the command value changing means, the amount of decrease in engine speed per unit time is first set as a threshold value. It is desirable to detect the command value at the following time and to learn the command value for setting the lockup clutch immediately before engagement based on the command value.

  Further, the lockup clutch control device of the present invention preferably has the above-described configuration, further comprising start control means for executing start control for starting the vehicle in the slip state of the lockup clutch, The start control means uses the learned value learned by the learning means as a command value for controlling the differential pressure of the lock-up clutch in order to bring the lock-up clutch into a state immediately before engagement in the start control. Adopted.

  According to the control device for a lockup clutch having such a configuration, the lockup clutch is brought into a slip state at a low vehicle speed, so that the lockup clutch engagement shock is likely to be increased, and thus the lockup clutch control device can be obtained in a state in which it is difficult to receive disturbance. By adopting the obtained learning value, a significant reduction in engagement shock can be expected.

  The start control means preferably executes start control only when learning by the learning means is completed.

  According to the lockup clutch control device having such a configuration, it is possible to prevent the engine from starting and generating an engine stall or increasing the lockup clutch engagement shock before the learning value is acquired. it can.

  According to the control device for a lockup clutch of the present invention, it is possible to learn a command value for setting the lockup clutch to a state just before engagement in a state that is hardly affected by disturbance.

It is a schematic structure figure showing some vehicles concerning an embodiment of the invention. It is a schematic block diagram which shows the torque converter and automatic transmission which are applied to the vehicle shown in FIG. It is a figure which shows an example of the hydraulic control circuit of the torque converter with a lockup clutch. 3 is an operation table of the automatic transmission shown in FIG. 2. It is a block diagram which shows the structure of control systems, such as ECU. It is an example of the time chart which shows the signal pressure of the solenoid valve for slip control in a flex start control, and the solenoid valve for switching. It is an example of the time chart which shows the state of each part in the learning control in a reference form. It is a flowchart which shows the execution procedure of the learning control in a reference form. It is an example of a time chart showing the various parts of the state in the learning control in the form of implementation. Is a flowchart showing an execution procedure of the learning control in the form of implementation.

Hereinafter, it will be described with reference to the drawings implementation embodiment of the present invention. For convenience, the reference form similar to the embodiment will be described first, and then the part of the embodiment different from the reference form (mainly learning control) will be described. The vehicle shown in FIG. 1 is an FF (front engine / front drive) type vehicle, and is equipped with an engine 1, a torque converter 2 with a lock-up clutch, an automatic transmission 3, a differential gear device 5, an ECU 200, and the like. . A crankshaft (not shown), which is an output shaft of the engine 1, is connected to the torque converter 2, and the output of the engine 1 is transmitted to the left and right via the torque converter 2, the automatic transmission 3, the differential gear device 5, and the like. It is transmitted to the drive wheels 6 and 6.

In this form state, the automatic transmission, although mentioned planetary gear type transmission setting a gear ratio (gear position) using a clutch and brake and a planetary gear unit as an example, adjusting the transmission ratio steplessly It is also possible to apply other automatic transmissions such as a belt type continuously variable transmission.

-Engine-
The engine 1 is, for example, a multi-cylinder gasoline engine, and the engine 1 is provided with an engine speed sensor 211 that detects the speed of the engine 1, a water temperature sensor 217 that detects the cooling water temperature of the engine, and the like.

  Air whose flow rate is adjusted by an electronically controlled throttle valve 11 is sucked into the engine 1. The opening of the throttle valve 11 is adjusted by the ECU 200 so that an optimum intake air amount (target intake air amount) corresponding to the operating state of the engine 1 such as the engine speed and the accelerator pedal depression amount (accelerator opening) is obtained. Drive control is performed via the motor 12.

-Torque converter-
As shown in FIG. 2, the torque converter 2 includes a pump impeller 21 on the input shaft side, a turbine runner 22 on the output shaft side, a stator 23 that exhibits a torque amplification function, and a one-way clutch 24. Between the turbine runner 22 and the turbine runner 22 through the fluid.

The torque converter 2 is provided with a lockup clutch 25 that directly connects the input side and the output side of the torque converter 2. As shown in FIG. 3, the lockup clutch 25 has a differential pressure ΔP between the hydraulic pressure in the engagement side oil chamber 26 and the hydraulic pressure in the release side oil chamber 27 (ΔP = hydraulic pressure P _ON in the engagement side oil chamber 26. A hydraulic friction clutch that is frictionally engaged with the front cover 2a by the oil pressure P _OFF in the release-side oil chamber 27, and is in a fully engaged state, a slip state, or a released state by controlling the differential pressure ΔP. It is said. In the present specification, the differential pressure ΔP is also referred to as a lockup differential pressure ΔP or a differential pressure ΔP of the lockup clutch 25.

  By bringing the lockup clutch 25 into a fully engaged state, the pump impeller 21 and the turbine runner 22 rotate integrally. Further, by setting the lock-up clutch 25 in the slip state, the turbine runner 22 rotates following the pump impeller 21 while sliding. On the other hand, the lockup clutch 25 is released by setting the lockup differential pressure ΔP to be negative.

-Automatic transmission-
The automatic transmission 3 illustrated in FIG. 2 includes a first transmission unit 300A mainly composed of a single pinion type first planetary gear unit 301, a single pinion type second planetary gear unit 302, and a double pinion type first planetary gear unit 301. A planetary gear type multi-stage having a second transmission unit 300B mainly composed of a three planetary gear unit 303 on a coaxial line, shifting the rotation of the input shaft 311 and transmitting it to the output shaft 312 and outputting from the output gear 313. It is a transmission. The output gear 313 meshes with the differential driven gear 5a (see FIG. 1) of the differential gear device 5. Since the automatic transmission 3 and the torque converter 2 are substantially symmetrical with respect to the center line, the lower half of the center line is omitted in FIG.

  The first planetary gear device 301 constituting the first transmission unit 300 </ b> A includes three rotating elements, a sun gear S <b> 1, a carrier CA <b> 1, and a ring gear R <b> 1, and the sun gear S <b> 1 is coupled to the input shaft 311. Further, the sun gear S1 is decelerated and rotated with respect to the input shaft 311 using the carrier CA1 as an intermediate output member by fixing the ring gear R1 to the housing case 310 via the third brake B3.

  In the second planetary gear device 302 and the third planetary gear device 303 constituting the second transmission unit 300B, four rotating elements RM1 to RM4 are configured by being partially connected to each other.

  Specifically, the first rotating element RM1 is configured by the sun gear S3 of the third planetary gear unit 303, and the ring gear R2 of the second planetary gear unit 302 and the ring gear R3 of the third planetary gear unit 303 are connected to each other. A second rotation element RM2 is configured. Further, the carrier CA2 of the second planetary gear device 302 and the carrier CA3 of the third planetary gear device 303 are connected to each other to constitute a third rotating element RM3. The fourth rotating element RM4 is configured by the sun gear S2 of the second planetary gear unit 302.

  In the second planetary gear device 302 and the third planetary gear device 303, the carriers CA2 and CA3 are configured by a common member, and the ring gears R2 and R3 are configured by a common member. Further, the pinion gear of the second planetary gear unit 302 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear unit 303.

  The first rotating element RM1 (sun gear S3) is integrally connected to the carrier CA1 of the first planetary gear device 301 that is an intermediate output member, and is selectively connected to the housing case 310 by the first brake B1 for rotation. Stopped. The second rotating element RM2 (ring gears R2 and R3) is selectively coupled to the input shaft 311 via the second clutch C2, and selectively to the housing case 310 via the one-way clutch F1 and the second brake B2. It is connected and stopped.

  The third rotation element RM3 (carriers CA2 and CA3) is integrally connected to the output shaft 312. The fourth rotation element RM4 (sun gear S2) is selectively coupled to the input shaft 311 via the first clutch C1.

  In the automatic transmission 3 described above, the first clutch C1, the second clutch C2, the first brake B1, the second brake B2, the third brake B3, the one-way clutch F1, and the like, which are friction engagement elements, are engaged in a predetermined state. The gear stage is set by combining or releasing.

  FIG. 4 is an engagement table for explaining the engagement operation of the clutch and brake for establishing each gear stage of the automatic transmission 3, wherein “◯” represents engagement and “×” represents release. Yes.

  As shown in FIG. 4, when the clutch C1 of the automatic transmission 3 is engaged, the first gear (1st) of the forward gear is established, and the one-way clutch F1 is engaged at the first gear. Further, the second brake B2 is engaged in the first-speed engine brake (EGB) range. When the first clutch C1 and the brake B1 are engaged, the forward gear 2nd speed (2nd) is established. When the first clutch C1 and the third brake B3 are engaged, the third forward speed (3rd) is established.

  Further, when the first clutch C1 and the second clutch C2 are engaged, the forward gear 4th (4th) is established. When the second clutch C2 and the third brake B3 are engaged, the forward gear 5th (5th) is established. When the second clutch C2 and the first brake B1 are engaged, the forward gear 6th (6th) is established. On the other hand, when the second brake B2 and the third brake B3 are engaged, the reverse gear stage (R) is established.

  The rotational speed (turbine rotational speed) of the input shaft 311 of the automatic transmission 3 is detected by the input shaft rotational speed sensor 213. Further, the rotation speed of the output shaft 312 of the automatic transmission 3 is detected by an output shaft rotation speed sensor 214. Based on the rotation speed ratio (output rotation speed / input rotation speed) obtained from the output signals of the input shaft rotation speed sensor 213 and the output shaft rotation speed sensor 214, the current gear position of the automatic transmission 3 can be determined. it can.

-Hydraulic control circuit-
It will now be described with reference to FIG. 3 for the hydraulic control circuit 100 in the form state. FIG. 3 shows only the main part of the hydraulic control circuit of the torque converter 2 with the lockup clutch 25. In FIG. 3, circuits used for other controls, such as a circuit for controlling the operation of the hydraulic friction engagement device (clutch C and brake B) for shifting the automatic transmission 3, are omitted. Yes.

The hydraulic control circuit 100 is provided with an oil pump 110 for sucking and pressure-feeding the hydraulic oil circulating in the oil pan 42. The hydraulic oil pumped from the oil pump 110 is a relief type primary regulator. The valve 101 regulates the first line pressure PL1. The primary regulator valve 101 generates a first line pressure PL1 that increases in response to a throttle pressure output from a throttle valve opening detection valve (not shown) and outputs the first line pressure PL1 to the first line oil passage 48. Similarly, the secondary regulator valve 102 is a relief type pressure regulating valve, and the hydraulic oil discharged from the primary regulator valve 101 for pressure regulation (relief) is regulated based on the throttle pressure. The second line pressure PL2 corresponding to the output torque of 1 is generated. The modulator valve 103 is a pressure reducing valve that uses the first line pressure PL1 as a source pressure, and generates a constant modulator pressure P _M having a preset magnitude. The first line pressure PL1 is supplied as a source pressure or the like of a transmission control hydraulic circuit (not shown) for controlling the gear stage of the automatic transmission 3.

As shown in FIG. 3, the lock-up clutch 25, hydraulic oil through the hydraulic P _ON and the release oil passage 27a of the engaging-side oil chamber 26 of the hydraulic oil is supplied via the engagement-side oil passage 26a Is a hydraulic friction engagement clutch that is frictionally engaged with the front cover 2a by a differential pressure ΔP (lockup differential pressure ΔP) with respect to the hydraulic pressure P _OFF in the release-side oil chamber 27.

  The hydraulic control circuit 100 includes a switching solenoid valve 105, a clutch switching valve 108, a slip control solenoid valve 104, a lockup control valve 109, and the like.

Switching solenoid valve 105 outputs a switching signal pressure P _SW on and off according to the drive current supplied from the ECU 200 (Otay not shown in FIG. 3). Clutch switching valve 108 in accordance with the switching signal pressure P _SW of switching solenoid valve 105, the off-side position to the lock-up clutch 25 and the released state (OFF) and the lock-up clutch 25 on the side position to the engaged state ( ON).

The slip control solenoid valve 104 has a signal pressure P that continuously changes in accordance with a drive current (command value for controlling the lockup differential pressure ΔP) supplied from the ECU 200 (not shown in FIG. 3). Output _SLU . The lockup control valve 109 controls the slip amount of the torque converter 2 in accordance with the signal pressure P _SLU when the clutch switching valve 108 is in the on-side position (ON).

The clutch switching valve 108 includes a release side port 74 that communicates with the release side oil chamber 27, an engagement side port 76 that communicates with the engagement side oil chamber 26, and an input port 78 that is supplied with the second line pressure PL2. When the lockup clutch 25 is disengaged, the discharge port 80 for discharging the hydraulic oil supplied from the engagement side oil chamber 26 to the engagement side port 76 through the engagement side oil passage 26a when the lockup clutch 25 is disengaged is released. A detour port 82 communicated with the release side port 74 communicated with the side oil chamber 27 via the release side oil passage 27a, and a relief port supplied with hydraulic oil discharged for pressure regulation from the secondary regulator valve 102 84, a spool valve element 181 for switching the states of the plurality of ports, and a compression valve for urging the spool valve element 181 toward the off-side position (OFF). And Rubane 182, the switching signal pressure P to end by applying a switching signal pressure P _SW from the switching solenoid valve 105 to generate a thrust directed to the on-side position (ON) of the spool 181 _An oil chamber 90 for receiving _SW . The discharge port 80 communicates with the relief port 84 when the lockup clutch 25 is engaged, and discharges hydraulic oil supplied from the secondary regulator valve 102 to the relief port 84 for pressure regulation. Note that the left half of the center line of the clutch switching valve 108 shown in FIG. 3 shows the state where the spool valve element 181 is located at the OFF side position (OFF), and the right half of the center line is at the ON side position (ON). The state in which the spool valve element 181 is located is shown.

The lock-up control valve 109 includes a spool valve element 191 that switches the state of the valve, a compression coil spring 192 that biases the spool valve element 191 toward the slip side position (SLIP), and an engagement side of the torque converter 2. The oil chamber 96 that receives the oil pressure P _ON in the oil chamber 26 and applies a thrust force to the spool valve element 191 in the direction toward the slip side position, and the oil pressure P _OFF in the release side oil chamber 27 of the torque converter 2 receives the spool. The oil chamber 98 for applying a thrust force toward the fully engaged side position (ON) to the valve element 191 and the signal pressure P _SLU output from the slip control solenoid valve 104 are received and completely engaged with the spool valve element 191. Oil chamber 92 for applying a thrust in the direction toward the side position (ON) and the second line pressure regulated by the secondary regulator valve 102 An input port 93 which L2 is supplied, the control port 94 the spool valve element 191 is communicated with the input port 93 when positioned on the slip side position (SLIP), and a drain port 95 is provided with. Note that the left half of the center line of the lock-up control valve 109 shown in FIG. 3 indicates that the spool valve element 191 is in the slip side position (SLIP), and the right half of the center line is that the spool valve element 191 is completely engaged. A state in the mating position (ON) is shown.

The slip control solenoid valve 104 reduces the modulator pressure P _M output from the modulator valve 103 in accordance with the drive current (command value) input from the ECU 200 to generate the signal pressure P _SLU . The lockup clutch 25 is controlled by the signal pressure P _SLU through the lockup control valve 109 in the range from the released state to the fully engaged state.

Switching solenoid valve 105 is de-energized state (off state), the switching signal pressure P _SW is a drain pressure, the in energized state (ON state) switching signal pressure P _SW and the modulator pressure P _M, the clutch switching It acts on the oil chamber 90 of the valve 108. When the modulator pressure P _M is supplied to the oil chamber 90, the spool valve element 181 of the clutch switching valve 108 is moved to the ON side position (ON) against the urging force of the compression coil spring 182. On the other hand, when the drain pressure is supplied to the oil chamber 90 of the clutch switching valve 108, the spool valve element 181 is moved to the off-side position (OFF) according to the urging force of the compression coil spring 182. In the following description, it is expressed that the switching signal pressure P _SW is supplied when the switching signal pressure P _SW is the modulator pressure P _M , and when the switching signal pressure P _SW is the drain pressure, the switching signal pressure is expressed. It expresses that pressure _PSW is not supplied.

In the clutch switching valve 108, when the switching solenoid valve 105 is excited and the switching signal pressure _PSW is supplied to the oil chamber 90 and the spool valve element 181 is positioned at the ON side position (ON), it is supplied to the input port 78. The second line pressure PL2 is supplied from the engagement side port 76 to the engagement side oil chamber 26 through the engagement side oil passage 26a. The second line pressure PL2 supplied to the engagement side oil chamber 26 becomes the hydraulic pressure P _ON . At the same time, the release-side oil chamber 27 communicates with the control port 94 of the lockup control valve 109 from the release-side oil passage 27a via the release-side port 74 and the bypass port 82. Then, the oil pressure P _OFF in the release side oil chamber 27 is regulated by the lock-up control valve 109, whereby the slip amount (slip rotation speed) of the torque converter 2 is controlled.

Specifically, when the spool valve element 181 of the clutch switching valve 108 is in the on-side position (ON), the signal pressure P _SLU supplied to the oil chamber 92 of the lockup control valve 109 causes the spool valve element 191 to move. Since the hydraulic pressure is lower than the hydraulic pressure moved to the fully engaged side position (ON), the spool valve element 191 slips from the fully engaged side position (ON) due to the balance between the signal pressure P _SLU and the _urging force of the compression coil spring 192. It is held at an intermediate position between the side position (SLIP). As a result, the communication state between the control port 94 and the input port 93 and the drain port 95 changes continuously according to the signal pressure P _SLU, and the hydraulic pressure in the release-side oil chamber 27 that communicates with the control port 94. P _OFF also changes continuously. Thereby, the lockup differential pressure ΔP is continuously controlled according to the signal pressure P _SLU of the solenoid valve 104 for slip control, and the slip amount of the lockup clutch 25 is continuously controlled.

Further, when the spool valve element 181 of the clutch switching valve 108 is in the ON position (ON), the signal pressure P _SLU supplied to the oil chamber 92 of the lockup control valve 109 is set to the maximum pressure, and the spool valve element 191 is set. Is moved to the fully engaged position (ON), the communication between the input port 93 and the control port 94 is cut off, the supply of the second line pressure PL2 to the release-side oil chamber 27 is stopped, and the control is performed. The port 94 and the drain port 95 communicate with each other. As a result, the hydraulic oil in the release side oil chamber 27 is discharged from the control port 94 through the drain port 95, the lockup differential pressure ΔP is maximized, and the lockup clutch 25 is fully engaged.

  When the lock-up clutch 25 is in the slip state or the fully engaged state, the spool valve element 181 of the clutch switching valve 108 is in the on-side position (ON), so that the relief port 84 and the discharge port 80 communicate with each other. As a result, the hydraulic oil discharged from the secondary regulator valve 102 is discharged to a lubricating oil supply oil passage (not shown) via the clutch switching valve 108.

On the other hand, in the clutch switching valve 108, without switching signal pressure P _SW is supplied to the oil chamber 90, the spool valve element 181 is positioned off side position (OFF) by the biasing force of the compression coil spring 182, the input The second line pressure PL2 supplied to the port 78 is supplied from the release side port 74 to the release side oil chamber 27 through the release side oil passage 27a. Further, the hydraulic oil in the engagement side oil chamber 26 is supplied to the engagement side port 76 through the engagement side oil passage 26a, and is discharged from the discharge port 80 to a lubricating oil supply oil passage (not shown). As a result, the lockup clutch 25 is released.

-Shift operation device-
In the vicinity of the driver's seat of the vehicle, a shift operation device including a shift lever provided in a displaceable manner is disposed. A P (parking) position, an R (reverse) position, an N (neutral) position, and a D (drive) position are set in the shift operation device. When the driver displaces the shift lever to a desired position, these positions of P position, R position, N position, and D position are detected by a shift position sensor 216 (see FIG. 5). An output signal of the shift position sensor 216 is input to the ECU 200.

  The P position and the N position are non-traveling positions (non-traveling range) selected when the vehicle is not traveling, and the R position and D position are traveling positions (forward traveling range, selected when the vehicle is traveling). Reverse travel range). For example, when the D position is selected by the shift lever, an automatic transmission mode in which the automatic transmission 3 is automatically shifted according to the driving state of the vehicle is set, and a plurality of forward gear stages ( (Sixth forward speed) is automatically controlled for shifting.

-ECU-
As shown in FIG. 5, the ECU 200 includes a CPU 201, a ROM 202, a RAM 203, a backup RAM 204, and the like.

  In the ROM 202, in addition to the control related to the basic driving of the vehicle, the shift control for setting the gear stage of the automatic transmission 3 according to the traveling state of the vehicle, the lock-up clutch 25 in the engaged state, the slip state, or the complete engagement Various programs including programs for executing lock-up control for switching to a state, neutral control for setting the automatic transmission 3 to a neutral state, and the like are stored.

  The CPU 201 executes arithmetic processing based on various control programs and maps stored in the ROM 202. The RAM 203 is a memory that temporarily stores calculation results of the CPU 201, data input from each sensor, and the backup RAM 204 is a non-volatile memory that stores data to be saved when the engine 1 is stopped. is there.

  The CPU 201, ROM 202, RAM 203, and backup RAM 204 are connected to each other via a bus 207, and are connected to an input interface 205 and an output interface 206.

  The input interface 205 includes an engine speed sensor 211, a throttle opening sensor 212, an input shaft speed sensor 213, an output shaft speed sensor 214, an accelerator position sensor 215, a shift position sensor 216, a water temperature sensor 217, and an intake air amount. Such as an air flow meter 218 that detects the intake air temperature sensor 219, an ATF oil temperature sensor 220 that detects the temperature of the hydraulic oil in the automatic transmission 3, a vehicle speed sensor 221, a brake switch 222 that detects whether the brake pedal is operated, an odometer, etc. A travel distance integrator 223 and the like are connected, and signals from these sensors are input to the ECU 200.

  Connected to the output interface 206 are the throttle motor 12 of the throttle valve 11, the injector 13 for injecting fuel into the engine 1, the igniter 14 for controlling the ignition timing of the spark plug, the hydraulic control circuit 100, and the like.

  The ECU 200 executes various controls of the engine 1 including opening control of the throttle valve 11 of the engine 1, ignition timing control, fuel injection amount control, and the like based on the output signals of the various sensors described above.

  The ECU 200 also outputs a solenoid control signal (hydraulic command signal) for setting the gear of the automatic transmission 3 to a hydraulic control circuit (not shown). On the basis of this solenoid control signal, the excitation / non-excitation of the linear solenoid valve and the ON-OFF solenoid valve of the hydraulic control circuit is controlled to constitute a predetermined shift gear stage (1st to 6th speeds). The clutches C1 to C2, the brakes B1 to B3, the one-way clutch F1 and the like of the automatic transmission 3 are engaged or released in a predetermined state.

Further, the ECU 200 outputs a lockup clutch control signal to the hydraulic control circuit 100. Based on the lock-up clutch control signal, the signal pressure P _SW of the switching solenoid valve 105 of the hydraulic control circuit 100 and the signal pressure P _{SLU of the} solenoid valve for slip control are controlled, and the clutch switching valve 108 and the lock-up control valve 109 are controlled. The lockup clutch 25 is controlled to be in a released state, a slip state, or a fully engaged state via

-Neutral control-
The ECU 200 controls the hydraulic control circuit (not shown) of the automatic transmission 3 to reduce or release the engagement force of the clutch C1 when a predetermined neutral control start condition is satisfied during the idling operation of the engine 1. Thus, neutral control is performed to bring the automatic transmission 3 into the neutral state.

  The neutral control start condition is, for example, that the vehicle speed is zero, the shift position is “D position”, the brake pedal is depressed, and the amount of operation of the accelerator pedal is zero (the accelerator is off). It is supposed to be. The vehicle speed is detected based on the output signal of the vehicle speed sensor 221, the shift position is detected based on the output signal of the shift position sensor 216, and the depression operation of the brake pedal is detected based on the output signal of the brake switch 222. Is detected based on the output signal of the accelerator opening sensor 215.

  Neutral control is terminated when a predetermined control termination condition is satisfied. The control end condition is, for example, a case where it is detected that the depression operation of the brake pedal is released based on an operation detection signal from the brake switch 222. When the control end condition for the neutral control is satisfied, the ECU 200 recovers the engagement force of the clutch C1 that has decreased or released the engagement force.

-Flex start control-
Hereinafter, the flex start control executed by the ECU 200 will be described. This flex start control is a control for starting the vehicle with the lock-up clutch 25 slipping.

ECU 200 starts flex start control when a predetermined flex start control start condition is satisfied. The flex start control start condition is, for example, that an increase in the accelerator opening or the throttle opening from zero is detected when the vehicle speed is zero and the brake operation state is a non-operation state. However, in this form state, flex-start control is executed only when the acquisition of the learning value to be described later is completed. The vehicle speed is detected based on the output signal of the vehicle speed sensor 221, the brake operating state is detected based on the output signal of the brake switch 222, and the accelerator opening is detected based on the output signal of the accelerator opening sensor 215. The throttle opening is detected based on the output of the throttle opening sensor 212.

As shown in the time chart of FIG. 6, ECU 200 is beginning (time t1) of the flex-start control, by the action of switching signal pressure P _SW output from the switching solenoid valve 105 on the side position of the clutch switching valve 108 (ON) and the first fill of the signal pressure P _SLU output from the slip control solenoid valve 104 is executed. After the first fill is executed, the ECU 200 maintains the signal pressure P _SLU at a constant pressure P1 (constant pressure standby pressure) for a predetermined time (time t2 to t3). This pressure P1 is a value that forms a lockup differential pressure ΔP that is brought into a state immediately before the lockup clutch 25 is engaged (that is, a state immediately before the slip state is shifted from the released state). The drive current (command value) that the ECU 200 supplies to the slip control solenoid valve 104 to set the signal pressure P _SLU to the pressure P1 is acquired by learning control to be described later.

After the signal pressure PSLU output from the slip control solenoid valve 104 is maintained at the constant pressure standby pressure (pressure P1) for the predetermined time, the signal pressure PSLU is further increased by the sweep control, and the engagement force of the lockup clutch 25 is increased. Amplified and feedback control is started to cause the actual slip amount Ns of the torque converter 2 to follow the target slip amount Nsm. In the present form state, the signal pressure PSLU at the start of sweep control is equal to the above pressure P1.

  The flex start control is ended when a predetermined control end condition such as the vehicle speed reaches a predetermined level is satisfied.

-Learning control-
The ECU 200 performs learning control for learning the drive current (command value) to be supplied to the slip control solenoid valve 104 in order to set the signal pressure P _SLU output from the slip control solenoid valve 104 to the pressure P1. Run. Hereinafter, this learning control will be described.

When a predetermined learning control start condition is satisfied, ECU 200 changes the learning execution flag from “0” to “1” at time t11 and applies signal pressure to slip control solenoid valve 104 as shown in the time chart of FIG. the P _SLU supplies a driving current to an initial value P0 (command value), the switching signal pressure P _SW of switching solenoid valve 105 in the oN state. At time t11, the learning completion flag continues to be in the initial value “0”.

  The predetermined learning start condition is based on the premise that (1) the shift range is the N range or the automatic transmission 3 is in the neutral state by the neutral control, and other learning start conditions include, for example, (2) vehicle speed (3) The temperature of the hydraulic oil in the automatic transmission 3 is equal to or higher than a predetermined temperature (for example, 60 ° C. or higher), and (4) the rotational speed of the engine 1 is within a predetermined range (for example, an idling rotational speed). And within a range of ± 150 rpm). The vehicle speed is determined by the output signal of the vehicle speed sensor 221, the shift range is determined by the output signal of the shift position sensor 216, and the temperature of the hydraulic oil of the automatic transmission 3 is determined by the output signal of the ATF oil temperature sensor 220. Is obtained from the output signal of the engine speed sensor 211.

  The initial value P0 is set to a value at which the lockup clutch 25 cannot be engaged (including a slip state) in consideration of individual differences between the lockup clutch 25 and the hydraulic control circuit 100.

After time t11, every time a predetermined time elapses (at times t12, t13, t14), the ECU 200 sets the drive current (command value) for the slip control solenoid valve 104 to a constant value (for example, 1% of the maximum value of the drive current). ) To increase the signal pressure P _SLU output from the slip control solenoid valve 104 in a stepwise manner (by changing the lockup clutch 25 from the released state to the engaged state). . The predetermined time is desirably a time required for the lock-up differential pressure ΔP to stabilize, for example, about 1 second to 2 seconds.

  When the absolute value of the slip amount of the torque converter 2 (slip rotational speed; engine rotational speed-turbine rotational speed) first falls below a predetermined threshold value (Xrpm) from time t14 to t15, the ECU 200 A driving current (command value) for the control solenoid valve 104 is detected, and a learning value of the driving current for causing the slip control solenoid valve 104 to generate the pressure P1 is acquired based on the detected driving current (command value). To do.

  In other words, the ECU 200 detects the drive current (command value) for the slip control solenoid valve 104 when the absolute value of the slip amount of the torque converter 2 first falls below a predetermined threshold (Xrpm), and the detected drive Drive for causing the slip control solenoid valve 104 to generate the pressure P1 with a drive current (command value at times t13 to t14) lower than the current (command value) by a certain value (for example, 1% of the maximum value of the drive current). Obtained as the current learning value.

  The predetermined threshold value (Xrpm) is the slip rotation speed when the lockup clutch 25 starts to move from the released state to the slip state. Such a slip rotation speed is obtained by experiments or the like, and usually takes a value within a range of 5 to 10 rpm.

At time t15, the ECU 200 returns the learning control execution flag from “1” to “0”, returns the signal pressure P _SLU of the solenoid valve 104 for slip control to the original value, and _switches the signal pressure for switching of the solenoid valve 105 for switching. _PSW is returned to OFF, and the learning completion flag is set from “0” to “1”.

  Next, the execution procedure of the learning control executed by the ECU 200 will be described based on the flowchart of FIG.

  In step ST1, it is determined whether the learning start condition described above is satisfied. Here, if an affirmative determination is made, the process proceeds to step ST2, and if a negative determination is made, the routine is exited.

  In step ST2, it is determined whether or not the learning completion flag is “1”, that is, whether or not the learning value of the drive current for causing the slip control solenoid valve 104 to generate the pressure P1 has been completed. To do. If a positive determination is made here, the process proceeds to step ST3, and if a negative determination is made, the process proceeds to step ST4.

  In step ST3, the difference between the current vehicle travel distance detected based on the output signal of the travel distance integrator 223 and the vehicle travel distance when the previous learning stored in the storage unit of the ECU 200 is completed is a predetermined value. It is determined whether or not it is longer than the travel distance. If a positive determination is made here, the process proceeds to step ST4. If a negative determination is made, the routine is exited. The vehicle travel distance when the previous learning is completed will be described later.

In step ST4, a predetermined driving current is supplied to the slip control solenoid valve 104 to set the signal pressure P _SLU to P0, and a predetermined driving current is supplied to the switching solenoid valve 105 to switch to the clutch switching valve 108. The signal pressure _PSW is supplied (the clutch switching valve 108 is switched to the ON position (ON)).

In step ST5, it is determined whether or not a predetermined time (for example, 1 second) has elapsed after the slip control solenoid valve 104 outputs the signal pressure P _SLU (= P0). If a positive determination is made here, the process proceeds to step ST6. If a negative determination is made, step ST5 is repeatedly determined.

  In step ST6, it is determined whether or not the absolute value of the slip amount of the torque converter 2 is equal to or smaller than a predetermined threshold (this threshold has already been described). If an affirmative determination is made here, the process proceeds to step ST7, and if a negative determination is made, the process proceeds to step ST10.

  In step ST7, the value of the drive current obtained by subtracting the constant value described above from the current drive current (command value) for the slip control solenoid valve 104 is stored in the storage unit (for example, the backup RAM 204).

  In step ST8, the current vehicle travel distance detected by the output signal of the travel distance integrator 223 is stored in the storage unit (for example, the backup RAM 204).

  In step ST9, the learning completion flag is changed from “0” to “1”, and this routine is exited.

In step ST10, the signal pressure P _SLU output from the slip control solenoid valve 104 is increased by β, and the process returns to step ST5. Thereafter, every time step ST10 is performed, the signal pressure P _SLU of the slip control solenoid valve 104 is increased by β. Finally, an affirmative determination is made in step ST6, and a learning value is acquired in step ST7.

According to the control device for the lockup clutch according to the reference embodiment described above, the slip amount of the torque converter 2 is not easily affected except for the engagement operation of the lockup clutch 25, that is, the shift range is the N range or neutral. Since the learning control is executed in a state where the automatic transmission 3 is in the neutral state by the control, a suitable learning value can be obtained.

- implementation form -
The following describes implementation of the invention. Lockup clutch control apparatus according to the embodiment of this, the shift range is in that the learning control is executed when not running a by neutral control a D-range is different from the reference embodiment.

  That is, the ECU 200 sets one of the learning start conditions that the shift range is the D range and the neutral control is not executed and the vehicle speed is zero, and other learning start conditions include, for example, (1) automatic The temperature of the hydraulic oil of the transmission 3 is not less than a predetermined temperature (for example, 60 ° C. or more), and (2) the rotational speed of the engine 1 is within a predetermined range (for example, within ± 150 rpm with respect to the idling rotational speed). It is supposed to be.

When the learning start condition is satisfied, the ECU 200 changes the learning execution flag from “0” to “1” at time t11 and sets the signal pressure PSLU to the slip control solenoid valve 104 as shown in the time chart of FIG. A drive current (command value) having an initial value P0 (same as the initial value P0 described in the reference embodiment) is supplied, and a switching signal pressure PSW is supplied to the switching solenoid valve 105. The learning completion flag continues to be in the initial value “0” state.

After time t11, every time a predetermined time elapses (at times t12, t13, t14), the ECU 200 sets the drive current (command value) for the slip control solenoid valve 104 to a constant value (for example, 1% of the maximum value of the drive current). ) To increase the signal pressure PSLU output from the slip control solenoid valve 104 stepwise. The predetermined time is the same as that in the reference embodiment.

  Then, since the change rate ΔNe of the engine speed becomes equal to or less than a predetermined threshold value (−Y rpm / sec) during the time t14 to t15, it can be estimated that the lockup clutch 25 has started to be engaged. A driving current (command value) for the control solenoid valve 104 is detected, and a learning value of the driving current for causing the slip control solenoid valve 104 to generate the pressure P1 is acquired based on the detected driving current (command value). To do.

  That is, the ECU 200 detects a drive current (command value) for the slip control solenoid valve 104 when the engine speed change rate ΔNe is equal to or less than a predetermined threshold (−Y rpm / sec), and the detected drive current is detected. A driving current (command value at time t13 to t14) that is lower than the constant value (for example, 1% of the maximum value of the driving current) lower than (command value at time t13 to t14) is generated in the slip control solenoid valve 104 with the pressure P1. It is acquired as a learning value of the drive current for making it.

  The predetermined threshold value (−Y rpm / sec) is the rate of change of the engine speed when the lockup clutch 25 starts to move from the released state to the slip state. Such a change rate of the engine speed is obtained by experiments or the like.

At time t15, the learning control execution flag is returned from “1” to “0”, the signal pressure P _SLU of the slip control solenoid valve 104 is returned to the original value, and the switching signal pressure P _SW of the switching solenoid valve 105 is changed. Returning to OFF, the learning completion flag is set from “0” to “1”.

The execution procedure of the learning control executed by the ECU 200 in the present embodiment is as shown in the flowchart of FIG. That is, ECU 200 executes the same processing as in the reference embodiment in steps ST1 to ST5 and steps ST7 to ST10, and instead of determining whether or not the slip rotation speed has become a predetermined threshold value or less in the determination step of ST6. Then, it is determined whether or not the rate of change ΔNe of the engine speed Ne is equal to or lower than a predetermined threshold value (−Y rpm / sec). If an affirmative determination is made here, the process proceeds to step ST7. If a negative determination is made, the process proceeds to ST10.

According to the lockup clutch control apparatus according to the implementation embodiments as mentioned above, hardly affected engine speed other than the lock-up clutch 25 engaged operating state, that is, the shift range is a D range neutral Since the learning control is executed in a state where the control is not executed and the vehicle speed is zero, a suitable learning value can be obtained.

  The present invention is applicable to, for example, a control device for a lock-up clutch mounted on an automobile.

1 Engine 2 Torque Converter 25 Lockup Clutch 100 Hydraulic Control Circuit 104 Slip Control Solenoid Valve 109 Lockup Control Valve 200 ECU
211 Engine speed sensor 213 Input shaft speed sensor 221 Vehicle speed sensor

Claims (4)

No automatic transmission becomes a neutral state to a row range shift range is run, and when the vehicle speed is zero, the command value variation means for varying the command value for controlling the differential pressure of the lock-up clutch,
An engine speed detecting means for detecting the engine speed ;
Based on the change in engine speed with respect to the fluctuating command value, the command value when the lock-up clutch moves from the disengaged state to the slip state is detected, and based on the command value, the lock-up clutch is in a state immediately before engagement. Learning means for learning command values to be performed;
A control device for a lock-up clutch. In the lockup clutch control device according to claim 1,
The command value changing means changes the command value stepwise from the side where the lockup clutch is released to the side where it is engaged.
The learning means detects the command value when the decrease amount per unit time of the engine speed first becomes a threshold value or less when the command value is changed stepwise by the command value changing means. A control device for a lock-up clutch that learns a command value for setting the lock-up clutch in a state immediately before engagement based on the command value . In the lockup clutch control device according to claim 1 or 2,
A start control means for executing start control for starting the vehicle in a slip state with the lock-up clutch;
The start control means uses the learned value learned by the learning means as a command value for controlling the differential pressure of the lock-up clutch in order to bring the lock-up clutch into a state immediately before engagement in the start control. Adopted control device for lock-up clutch. The control device for a lockup clutch according to claim 3,
The start-up control means is a lock-up clutch control device that executes start-up control only when learning by the learning means is completed .

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