JP4701844B2 - Shift control device for automatic transmission for vehicle - Google Patents

Description

  The present invention relates to a shift control device for an automatic transmission for a vehicle that can suppress an undershoot (drop) of an input shaft rotation speed that occurs during a clutch-to-clutch downshift period that is executed during deceleration. is there.

When the clutch-to-clutch downshift is executed, when the downshift is judged, the engagement pressure of the release side hydraulic friction engagement device engaged to achieve the gear stage before the downshift is reduced. In addition, there is known a shift control device for an automatic transmission for a vehicle that executes a shift hydraulic pressure control for increasing an engagement pressure of an engagement-side hydraulic friction engagement device for achieving a gear stage after a shift. The device described in Patent Document 1 is an example, and at the time of clutch-to-clutch downshift during deceleration traveling, the maximum undershoot amount of the input shaft rotation speed of the automatic transmission is obtained, and based on the maximum undershoot amount. The engagement pressure of the release side frictional engagement device is corrected by learning control to suppress a shock or the like due to undershoot. The amount of undershoot is the amount by which the actual input shaft rotational speed falls with respect to the synchronous rotational speed of the input shaft at the gear stage before the shift. The synchronous rotational speed of the input shaft is the output shaft rotational speed and the gear ratio of the gear stage before the shift, etc. It is requested from.
JP 2004-183757 A

  By the way, when the automatic transmission starts shifting, the input shaft rotational speed and the output shaft rotational speed may temporarily change suddenly due to disturbance such as rattling caused by backlash of the power transmission system. There is a possibility that the undershoot amount is erroneously determined to be excessive and erroneous learning control is performed based on the determination result.

  The present invention has been made against the background of the above circumstances. The object of the present invention is to provide a disengagement side frictional engagement device based on the amount of undershoot of the input shaft rotational speed during clutch-to-clutch downshift during deceleration. When the engagement pressure is corrected by learning control, it is intended to prevent erroneous learning control from being performed due to disturbance such as rattling.

In order to achieve such an object, according to a first aspect of the present invention, there is provided a clutch toe in which a shift is achieved by executing release of a disengagement side frictional engagement device and engagement of an engagement side frictional engagement device during deceleration traveling. A shift control device for an automatic transmission for a vehicle in which a clutch down shift is performed, wherein (a) an undershoot of an input shaft rotational speed of the automatic transmission associated with the shift during the clutch-to-clutch down shift during the deceleration traveling An undershoot amount calculating means for sequentially calculating the amount; and (b) integrating the undershoot amount until the engagement-side friction engagement device is in a torque transmission state in the clutch-to-clutch downshift during the deceleration traveling. And an integral value calculating means for obtaining an undershoot amount integral value, and (c) correcting the engagement pressure of the disengagement side frictional engagement device based on the magnitude of the undershoot amount integral value by learning control. A learning control unit, Bei give a, and, (d) said integral value calculating means includes integral means for sequentially adding an undershoot amount which are sequentially calculated by (d-1) wherein the undershoot amount calculating means that, ( d-2) determination means for determining whether or not the engagement side frictional engagement device is in a torque transmission state; and (d-3) an added value obtained by the integration means until the determination is made. And an integral value determining means that sets the undershoot amount integral value as the integral value .

According to a second aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to the first aspect, the determination unit is a maximum determination unit that determines whether or not an undershoot amount of the input shaft rotational speed is maximized. It is characterized by.

  According to a third aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to the first or second aspect, when a shift command for the clutch-to-clutch downshift is issued, the engagement pressure of the disengagement side frictional engagement device is increased. While holding for a predetermined time at a predetermined standby pressure that is lower than the original pressure and higher than the release start pressure of the disengagement side frictional engagement device, it is continuously decreased to a constant rate of change. Further, the present invention is characterized by comprising a shift hydraulic pressure control means for increasing the engagement pressure of the engagement side frictional engagement device so that the input shaft rotation speed continuously increases at a constant increase rate.

  According to a fourth aspect of the present invention, in the shift control device for an automatic transmission for a vehicle according to the third aspect, the learning control means is configured to control the release-side frictional engagement device when the integrated value of the undershoot exceeds a predetermined value. The learning correction is performed so as to increase the standby pressure.

  In such a shift control device for an automatic transmission for a vehicle, an undershoot amount of the input shaft rotation speed of the automatic transmission is sequentially calculated during clutch-to-clutch downshifting during deceleration travel, and an engagement side frictional engagement is calculated. The undershoot amount integrated value is obtained by integrating the undershoot amount until the combined device enters the torque transmission state, and the engagement pressure of the disengagement side frictional engagement device is determined by learning control based on the undershoot amount integrated value. To compensate, even if the input shaft rotational speed and output shaft rotational speed change temporarily due to disturbance caused by rattling of the power transmission system at the start of shifting, the effect on the undershoot integral value is small and the undershoot Learning control based on the quantity is stably performed with high accuracy.

  Here, the input shaft rotation speed during the clutch-to-clutch downshift during deceleration travel is increased based on the transmission torque when the engagement-side frictional engagement device enters the torque transmission state, and the input shaft rotation speed undershoots. In the present invention, since the undershoot amount is integrated by integrating the undershoot amount until the engagement side frictional engagement device is in the torque transmission state, the engagement side frictional engagement device is obtained. Thus, the learning control of the engagement pressure of the disengagement side frictional engagement device is performed with higher accuracy.

  In the second aspect of the invention, since the learning control is performed by obtaining the integral value of the undershoot amount until the undershoot amount of the input shaft rotational speed becomes maximum, the influence of the transmission torque of the engagement side frictional engagement device is satisfactorily reduced. On the other hand, the undershoot amount integrated value reflects the undershoot amount resulting from the decrease in the engagement pressure of the disengagement side frictional engagement device and is less affected by disturbance due to rattling of the power transmission system at the start of shifting Based on the above, the engagement pressure of the disengagement side frictional engagement device can be learned and controlled with high accuracy. That is, the engagement side frictional engagement device starts torque transmission with the engagement torque before the undershoot amount of the input shaft rotational speed becomes maximum, but compared with that after the undershoot amount becomes maximum. While the engagement torque (transmission torque) is small and has little effect, the amount of data is small and the undershoot amount integrated value is small before the undershoot amount reaches its maximum, and the influence of disturbance such as rattling increases. It is appropriate to use an integrated value of the undershoot amount until the undershoot amount becomes maximum.

  In the third aspect of the present invention, when a shift command for clutch-to-clutch downshifting is issued, the engagement pressure of the disengagement side frictional engagement device is lower than its original pressure and the disengagement side frictional engagement device is operated by the transmission oil pressure control means. Is maintained at a predetermined standby pressure that is set higher than the release start pressure for a predetermined period of time, and then continuously decreased so as to have a constant rate of change, while the input shaft rotation speed continues at a constant rate of increase. Since the engagement pressure of the engagement side frictional engagement device is increased so as to increase, the clutch-to-clutch downshift is preferably executed while suppressing the shift shock.

  In the fourth aspect of the invention, when the integrated value of the undershoot amount of the input shaft rotation speed exceeds a predetermined value, the release-side frictional engagement device is used for learning correction so as to increase the standby pressure of the release-side frictional engagement device. Can be reliably maintained in the engaged state to suppress undershoot. That is, when suppressing the undershoot by extending the standby pressure holding time, if the standby pressure is low, the disengagement friction engagement device is brought into the engaged state no matter how long the standby pressure holding time is increased. It is not possible to suppress undershoot.

  As the automatic transmission, for example, a stepped automatic transmission such as a planetary gear type or a parallel shaft type is preferably used, and any clutch-to-clutch shift may be performed by at least a partial downshift. The present invention does not necessarily have to be applied to all clutch-to-clutch down shifts, and may be applied only to some clutch-to-clutch down shifts.

  The engagement-side friction engagement device and the release-side friction engagement device are preferably hydraulic ones controlled by the transmission hydraulic pressure control means as in the third aspect of the invention. Although it is controlled so as to change with a predetermined change pattern, other friction engagement devices such as an electromagnetic type can also be used. The engagement-side friction engagement device and the release-side friction engagement device are a single plate type or multiple plate type clutch or brake, a belt type brake, or the like that is engaged by an actuator such as a hydraulic cylinder.

  If the release timing of the disengagement side frictional engagement device is too early in the clutch-to-clutch downshift during such a deceleration traveling, in a driven state where the power source is rotationally driven by an input from the wheel side during the deceleration traveling. As a result, the input shaft rotation speed decreases and undershoot occurs. The undershoot of the input shaft rotational speed is a phenomenon in which the actual input shaft rotational speed decreases with respect to the synchronous rotational speed of the input shaft at the gear stage before the gear shift. The decrease amount (drop amount) at that time is the undershoot amount. Yes, the synchronous rotation speed of the input shaft is obtained from the output shaft rotation speed and the gear ratio of the gear stage before the shift.

  The input shaft of the automatic transmission is, for example, the turbine shaft of the torque converter when power is transmitted from the engine via the torque converter, and the motor shaft when power is transmitted from the electric motor. When this occurs, the input shaft rotation speed is increased with the progress of the subsequent downshift, that is, with the engagement of the engagement side frictional engagement device, so that a shock easily occurs at that time. For this reason, it is desirable that the undershoot amount be as small as possible within a range that does not cause a tie-up in which the engagement-side and release-side friction engagement devices are engaged together.

  In order to prevent the undershoot, for example, the standby pressure holding time of the release side frictional engagement device may be lengthened and the release timing may be delayed, but the standby pressure of the release side frictional engagement device as in the fourth aspect of the invention. Even if is increased, the same effect can be obtained if the subsequent rate of change is similar. In other words, the engagement pressure corrected by the learning control means by the learning control may be any one that affects the undershoot amount. Specifically, the standby pressure size and the standby pressure holding time are preferably used. The rate of change in the engagement pressure may be corrected by learning control, and so on, depending on the mode of engagement pressure control (such as a hydraulic control pattern).

The integral value calculating means integrates an undershoot amount until the engagement side frictional engagement device is in a torque transmission state to obtain an undershoot amount integral value. Means a state from a state where the engagement side frictional engagement device starts to have an engagement torque to a state where the engagement proceeds and the input shaft rotation speed starts to increase. That is, the amount of undershoot changes due to the engagement of the engagement side frictional engagement device, so that the engagement pressure of the release side frictional engagement device can be learned and controlled with higher accuracy by eliminating or reducing the influence. intended for the purpose of way, Ru is configured to undershoot of the input shaft rotational speed as in the second invention integrates the undershoot amount until the maximum if example embodiment. In carrying out the second invention, it may be determined whether or not the undershoot amount itself has become maximum, but since the input shaft rotational speed is substantially the same as the minimum time, the input shaft rotational speed is minimum. It is also possible to determine whether or not the undershoot amount integral value up to the time when the minimum value is reached.

The integral value calculating means includes (a) integrating means for sequentially adding the undershoot amounts sequentially calculated by the undershoot amount calculating means, and (b) whether or not the engagement side frictional engagement device is in a torque transmission state. For example, a maximum determination means for determining that the amount of undershoot has become the maximum, and (c) the added value (integration value) obtained by the integration means until the determination is made is under And an integral value determining means for setting the shoot amount integral value. In order to prevent misjudgment due to temporary changes in rotational speed due to rattling of the power transmission system at the start of shifting, the determination means is maximal from changes in the amount of undershoot and rotational speed within a predetermined time. It is desirable to determine the minimum or 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 horizontally-mounted vehicle drive device such as an FF (front engine / front drive) vehicle. An output of an engine 10 constituted by an internal combustion engine such as a gasoline engine includes a torque converter 12, The power is transmitted to drive wheels (front wheels) (not shown) through a power transmission device such as the automatic transmission 14 and the differential gear device 16. The torque converter 12 includes a pump impeller 20 connected to the crankshaft 18 of the engine 10, a turbine impeller 24 connected to the input shaft 22 of the automatic transmission 14, and a non-rotating member via a one-way clutch 26. And a lockup clutch 32 for directly connecting the crankshaft 18 to the input shaft 22 via a damper (not shown). A mechanical oil pump 21 such as a gear pump is connected to the pump impeller 20 and is driven to rotate together with the pump impeller 20 by the engine 10 so as to generate hydraulic pressure for shifting or lubricating. The engine 10 is a driving force source for vehicle travel, and the torque converter 12 is a fluid coupling.

  The automatic transmission 14 is coaxially disposed on the input shaft 22 and a carrier and a ring gear are connected to each other to thereby form a so-called CR-CR coupled planetary gear mechanism. A first planetary gear unit 40 and a second planetary gear unit 42; a set of third planetary gear units 46 arranged coaxially on a counter shaft 44 parallel to the input shaft 22; and a shaft end of the counter shaft 44 An output gear 48 that is fixed and meshes with the differential gear device 16 is provided. The components of the planetary gear units 40, 42, 46, that is, the sun gear, the ring gear, and the carrier that rotatably supports the planet gears meshing with them are selectively connected to each other by four clutches C0, C1, C2, and C3. Alternatively, the three brakes B1, B2, and B3 are selectively connected to the housing 28 that is a non-rotating member. The two one-way clutches F1 and F2 are engaged with each other or with the housing 28 depending on the rotation direction. Since the differential gear device 16 is configured symmetrically with respect to the axis (axle), the lower side is not shown.

  The first planetary gear unit 40, the second planetary gear unit 42, the clutches C0, C1, C2, the brakes B1, B2, and the one-way clutch F1 arranged coaxially with the input shaft 22 are moved forward and reverse by four stages. A one-stage main transmission unit MG is configured, and a set of planetary gear unit 46, clutch C3, brake B3, and one-way clutch F2 arranged on the counter shaft 44 constitute a sub-transmission unit, that is, an underdrive unit U / D. It is configured. In the main transmission unit MG, the input shaft 22 is connected to the carrier K2 of the second planetary gear device 42, the sun gear S1 of the first planetary gear device 40, and the sun gear S2 of the second planetary gear device 42 via the clutches C0, C1, and C2. Each is connected. The ring gear R1 of the first planetary gear unit 40 and the carrier K2 of the second planetary gear unit 42 are connected, and the ring gear R2 of the second planetary gear unit 42 and the carrier K1 of the first planetary gear unit 40 are connected to each other. The sun gear S2 of the second planetary gear unit 42 is connected to the housing 28 that is a non-rotating member via a brake B1, and the ring gear R1 of the first planetary gear unit 40 is a housing 28 that is a non-rotating member via a brake B2. It is connected to. A one-way clutch F1 is provided between the carrier K2 of the second planetary gear unit 42 and the housing 28 which is a non-rotating member. The first counter gear G1 fixed to the carrier K1 of the first planetary gear device 40 and the second counter gear G2 fixed to the ring gear R3 of the third planetary gear device 46 are meshed with each other. In the underdrive unit U / D, the carrier K3 and the sun gear S3 of the third planetary gear unit 46 are connected to each other via the clutch C3, and between the sun gear S3 and the housing 28 that is a non-rotating member, A brake B3 and a one-way clutch F2 are provided in parallel.

The clutches C0, C1, C2, and C3 and the brakes B1, B2, and B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are controlled by a hydraulic actuator such as a multi-plate clutch or a band brake. This is a hydraulic friction engagement device, and is hydraulically driven by excitation, de-energization, or a manual valve (not shown) of solenoid valves S4, SR and linear solenoid valves SL1, SL2, SL3, SLT, SLU, etc. of a hydraulic control circuit 98 (see FIG. 3). When the circuit is switched, for example, as shown in FIG. 2, the engaged and released states are switched, and the forward gear, the reverse gear, and the neutral gear according to the operation position (position) of the shift lever 72 (see FIG. 3). Each gear stage is established. “1st” to “5th” in FIG. 2 mean the first to fifth forward gears, “◯” means engagement, “×” means release, and “△” means only during driving. Means engagement. The shift lever 72 is, for example, in accordance with the shift pattern shown in FIG. 4, a parking position “P”, a reverse travel position “R”, a neutral position “N”, a forward travel position “D”, “4”, “3”, “2”. In the “P” and “N” positions, a neutral gear stage is established as a non-drive gear stage that cuts off power transmission. The parking mechanism mechanically prevents the drive wheels from rotating. Further, each of the five forward gears and one reverse gear established at the forward travel position such as “D” or the “R” position corresponds to a drive gear stage. In addition, as shown in FIG. 2, in the shift between the second speed gear stage and the third speed gear stage, the engagement or release of the clutch C0 and the release or engagement of the brake B1 are executed substantially simultaneously. The clutch-to-clutch shift achieved by Similarly, the shift between the third speed gear stage and the fourth speed gear stage is a clutch toe achieved by engaging or releasing the clutch C1 and releasing or engaging the brake B1 substantially simultaneously. In the clutch shift, the shift between the fourth speed gear stage and the fifth speed gear stage is achieved by engaging or releasing the clutch C3 and releasing or engaging the brake B3 substantially simultaneously. It is a toe clutch shift. In the hydraulic friction engagement device, the line pressure adjusted in accordance with the turbine torque T _T, that is, the input torque T _IN of the automatic transmission 14 or the throttle valve opening θ _TH that is a substitute value thereof is used as the original pressure. Used.

FIG. 3 is a block diagram for explaining a control system provided in the vehicle for controlling the engine 10 and the automatic transmission 14 of FIG. 1, and the operation amount (accelerator opening) Acc of the accelerator pedal 50 is an accelerator operation. It is detected by the quantity sensor 51. The accelerator pedal 50 is largely depressed according to the driver's required output amount, and corresponds to an accelerator operation member, and the accelerator pedal operation amount Acc corresponds to an output request amount. In addition, an electronic throttle valve 56 whose opening degree θ _TH is changed by a throttle actuator 54 is provided in the intake pipe of the engine 10. In addition, an intake air amount sensor 60 for detecting an intake air quantity Q of the engine rotational speed sensor 58, the engine 10 for detecting the rotational speed NE of the engine 10, the intake for detecting the temperature T _A of intake air The air temperature sensor 62, the electronic throttle valve 56 in a fully closed state (idle state) and a throttle sensor 64 with an idle switch for detecting the opening degree θ _TH , the rotational speed of the counter shaft 44 corresponding to the vehicle speed V (output shaft) a vehicle speed sensor 66 for detecting the corresponding) N _OUT of the rotational speed, the cooling water temperature sensor 68 for detecting the cooling water temperature T _W of the engine 10, a brake switch 70 for detecting the presence or absence of foot brake operation, the shift lever 72 lever position sensor 74 for detecting a lever position (operating position) P _SH of the turbine rotational speed NT (= input Turbine rotational speed sensor 76 for detecting force shaft rotational speed N _IN ), AT oil temperature sensor 78 for detecting AT oil temperature T _OIL which is the temperature of hydraulic oil in hydraulic control circuit 98, first counter gear A counter rotational speed sensor 80 for detecting the rotational speed NC of G1, an ignition switch 82, and the like are provided. From these sensors, the engine rotational speed NE, the intake air amount Q, the intake air temperature T _A , the throttle valve opening, Degree θ _TH , vehicle speed V (output shaft rotational speed N _OUT ), engine coolant temperature T _W , presence or absence of brake operation, lever position P _SH of shift lever 72, turbine rotational speed NT, AT oil temperature T _OIL , counter rotational speed NC A signal indicating the operation position of the ignition switch 82 is supplied to the electronic control unit 90. The brake switch 70 is an ON-OFF switch that switches between ON and OFF when the brake pedal that operates the service brake is depressed.

The electronic control unit 90 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 signals according to a program stored in the ROM in advance. By performing the processing, output control of the engine 10, shift control of the automatic transmission 14, and the like are executed, and the engine control and the shift control are divided as necessary. As for the output control of the engine 10, in addition to controlling the opening and closing of the electronic throttle valve 56 by the throttle actuator 54, the fuel injection valve 92 is controlled for controlling the fuel injection amount, and the ignition device 94 such as an igniter is controlled for controlling the ignition timing. Control. The electronic throttle valve 56 is controlled by, for example, driving the throttle actuator 54 based on the actual accelerator pedal operation amount Acc from the relationship shown in FIG. 5, and increasing the throttle valve opening θ _TH as the accelerator pedal operation amount Acc increases. . When the engine 10 is started, the crankshaft 18 is cranked by a starter (electric motor) 96. As for the shift control of the automatic transmission 14, the automatic transmission 14 shifts based on the actual throttle valve opening _.theta.TH and the vehicle speed V from, for example, a previously stored shift diagram (shift map) shown in FIG. The gear position to be determined is determined, that is, the shift determination from the current gear stage to the shift destination gear stage is executed, the shift output for starting the shift operation to the determined gear stage is executed, and the driving force change, etc. The solenoid valves S4 and SR of the hydraulic control circuit 98 are switched ON (excitation) and OFF (non-excitation) so as not to cause a gearshift shock or the durability of the friction material. The excitation states of the valves SL1, SL2, SL3, SLT, SLU, etc. are continuously changed. The solid line in FIG. 6 is an upshift line, and the broken line is a downshift line. As the vehicle speed V decreases or the throttle valve opening θ _TH increases, the gear ratio (= input shaft rotational speed N _IN / output shaft). rotational speed N _OUT) being adapted to be switched to a large low-speed side gear stage, the "1" to "5" first gear "1st" to the fifth speed gear stage "5th" in FIG. I mean.

FIG. 7 shows a main part of the hydraulic control circuit 98 and a part related to the 4 → 3 downshift. The hydraulic oil pumped from the hydraulic pump 21 is regulated by the relief-type first pressure regulating valve 100 to become the first line pressure PL1, and the hydraulic fluid discharged from the first pressure regulating valve 100 is the relief type. By adjusting the pressure by the second pressure regulating valve 102, the second line pressure PL2 is obtained. The first line pressure PL <b> 1 is supplied to the manual valve 104 that is interlocked with the shift lever 72. When the shift lever 72 is operated to the D position, the solenoid valves and shift such as this from the manual valve 104 of the same size as the first line pressure PL1 forward position pressure P _D is the linear solenoid valves SL1, SL2, SL3 Supplied to valves and control valves. In FIG. 7, the brake B1 and the clutch C1 that are released when the 4 → 3 downshift is achieved, the linear solenoid valve SL3 for directly controlling the engagement pressure P _{B1 of the} brake B1, A linear solenoid valve SL2 for directly controlling the engagement pressure P _{C1 of the} clutch C1, a hydraulic sensor 106 connected to the brake B1 for detecting the engagement pressure P _B1, and a detection of the engagement pressure P _C1 P _B1 control valve 110 and P _C1 control valve 112 that respectively adjust the engagement pressures P _B1 and P _C1 in accordance with the hydraulic pressure sensor 108 connected to the clutch C1 and the signal hydraulic pressure supplied from the linear solenoid valves SL3 and SL2. Is shown.

FIG. 8 is a functional block diagram for explaining a main part of the control function of the electronic control unit 90, that is, a shift control operation of the automatic transmission 14. FIG. 9 is a basic diagram of clutch-to-clutch down shift of the automatic transmission 14. It is a time chart which shows a control action. The vehicle state at the time of the basic control operation shown in FIG. 9 is that the engine rotational speed NE is reduced when the accelerator pedal 50 is not operated (when the accelerator is OFF) and the brake is being operated (brake ON) or not operated (brake OFF). In a state where the fuel cut (fuel cut-off to the engine 10) operation of the fuel cut device 118 that is executed when the fuel cut lower limit rotational speed (fuel cut release value C _F ) is higher than the preset value is continued. → 3 is the case where the clutch-to-clutch downshift control operation is executed. In FIG. 8, the rotational speed detecting means 120 detects the turbine rotational speed NT (= input shaft rotational speed N _IN ) based on, for example, a signal from the turbine rotational speed sensor 76 or an engine based on a signal from the engine rotational speed sensor 58. 10 is detected, or the output shaft rotational speed N _OUT is detected by a signal from the vehicle speed sensor 66. The inertia start determination means 130 determines whether or not the turbine rotational speed NT has started to increase with the shift to the low speed gear stage (third gear stage) during the downshift control operation during deceleration traveling ( t ₁ point).

The shift state determining means 122 determines whether or not a shift (hydraulic control) of the automatic transmission 14 is started based on an output signal of a shift hydraulic pressure control means 124 described later (at time t ₀ ), and the turbine The rotational speed NT substantially coincides with the rotational speed γ ₃ × N _OUT calculated from the output shaft rotational speed N _OUT detected by the vehicle speed sensor 66 and the gear ratio γ ₃ of the gear stage after the shift (third speed gear stage). determining the shift completion based on whether the (t ₂ time), the clutch C1 engagement pressure P _C1 detected by the oil pressure sensor 108 connected to the clutch C1 has reached the maximum value is fully engaged especially it determines shift hydraulic pressure control is completed by the shift hydraulic pressure control unit 124 on the basis of (t ₃ time points). Further, the fuel cut control means 126 determines whether or not fuel supply is necessary based on the engine speed NE, the accelerator pedal operation amount Acc, and the like, and issues a command to shut off the fuel supply to the engine 10. Output to the cutting device 118. For example, when the vehicle is decelerating when the accelerator pedal operation amount Acc is zero and the rotational speed NE of the engine 10 does not fall below a predetermined value (fuel cut release value C _F ), the fuel cut is activated. However, if the rotational speed NE of the engine 10 is reduced to the predetermined value, the output of the cutoff command is stopped so that the fuel cut is not activated, and the fuel cut state is released. . Based on the output signal of the fuel cut control means 126, the fuel cut state determination means 128 determines whether or not the fuel cut state caused by the fuel cut state has been released.

The shift hydraulic pressure control means 124 determines the gear stage to be shifted of the automatic transmission 14 based on the actual throttle valve opening θ _TH and the vehicle speed V from a shift map (shift map) stored in advance as shown in FIG. Then, a signal (shift command) is sent to the hydraulic control circuit 98 so as to change the engagement pressure of the hydraulic friction engagement device so that switching from the current gear to the gear to be shifted is executed. Is output. For example, in the case of the 4 → 3 clutch-to-clutch downshift shown in FIG. 9, the engagement-side hydraulic pressure for the linear solenoid valve SL2 that directly controls the engagement pressure P _C1 of the clutch C1, which is an engagement-side hydraulic friction engagement device. a drive signal S _PC1, a release-side hydraulic friction disengagement hydraulic pressure drive signal S _PB1 for the linear solenoid valve SL3 that directly controls the engagement pressure P _B1 of brake B1 is coupling device is output. Its engagement side hydraulic driving signal S _PC1 is given to the engagement pressure P _C1 in between a shift start point t ₀ of t _C1W time is set lower than the engagement starting pressure of the clutch C1 engagement pressure P _C1W so as to be pressure and standby pressure signal S _PC1W for waiting, constant rate of change of inertia start is set in advance in until time to be determined (t ₁ point) by pressure standby after the inertia start determination means 130 to The turbine rotation speed NT (input shaft rotation) between the sweep signal for continuously increasing the engagement pressure P _C1 and the time from the time t ₁ until the time when the gear shift state determining means 122 determines the end of gear shift (time t ₂ ). A feedback control signal for feedback control of the engagement pressure P _C1 so that the speed N _IN ) continuously increases at a preset constant increase rate, and the engagement pressure P _C1 is rapidly increased from time t _2. The Sequentially outputs a termination processing signal for the latch C1 complete engagement (t ₃ time points). A first fill signal larger than the standby _pressure signal _SPC1W is output within t _C1W time from the start of the shift and for the first t _C1A time in order to quickly supply hydraulic oil.

Furthermore, the release side hydraulic driving signal S _PB1 is the pre-shift start the engagement pressure P _B1 between the t _B1W time from the shift start based on pressure, ie hydraulic pressure supply source and a line pressure PL1 at a maximum engagement with application pressure A standby pressure signal _SPB1W for waiting for a constant pressure at a predetermined engagement pressure (standby pressure) _PB1W set to be lower than the pressure to become and slightly higher than the release start pressure of the brake B1; A sweep signal for sequentially releasing the brake B1 by decreasing the pressure P _B1 at a constant rate of change is output. _{Within the} time t _B1W from the start of the shift, and during the first t _B1A time, a drain signal for rapidly draining the hydraulic oil is output in order to quickly reduce the engagement pressure P _B1 to the standby pressure P _B1W . The t _B1W time is a standby pressure holding time in which the predetermined engagement pressure (standby pressure) P _B1W is kept at a constant pressure, and a time from when the shift starts until the engagement pressure P _B1 is continuously changed (decreased). That is, since it is the time from the start of the shift until the engagement pressure P _B1 starts to sweep, it is also the sweep control start time (decrease start time).

As described above, during the deceleration traveling, the shift hydraulic pressure control means 124 reduces the engagement pressure P _B1 of the brake B1 which is the release side hydraulic friction engagement device at the time of the 4 → 3 clutch to clutch downshift. When the engagement pressure P _C1 of the clutch C1 which is the combined hydraulic friction engagement device is increased, if the degree of overlap between the engagement of the brake B1 and the engagement of the clutch C1 is small, for example, the sweep control start time t _B1W Is short, the drive wheel (not shown) and the input shaft 22 are separated, that is, in a neutral tendency, and an undershoot occurs in which the engine rotational speed NE temporarily decreases together with the turbine rotational speed NT. When the rotational speed NE is increased, a shift shock (a phenomenon like momentary engine braking) occurs. In some cases, the shift time becomes longer. Further, when the neutral tendency is further increased, the undershoot amount of the engine speed NE is increased, and the operation by the fuel cut control means 126 is released, so that the fuel efficiency improvement effect by the fuel cut may be reduced. On the other hand, if the degree of overlap between the engagement of the brake B1 and the engagement of the clutch C1 is large, for example, if the sweep control start time t _B1W is long, the automatic transmission 14 is temporarily locked and the automatic transmission 14 may cause a tie-up state in which the output shaft torque temporarily decreases suddenly, resulting in a shift shock and deterioration of the hydraulic friction engagement device of the automatic transmission 14.

Therefore, by adjusting the sweep control start time t _B1W appropriately, it is basically possible to suppress the neutral tendency due to undershoot and prevent tie-up, but the standby pressure P _B1W is low and the brake is applied. When B1 slips, undershoot may not be suppressed even if the sweep control start time t _B1W is increased. Therefore, in this embodiment, the standby pressure signal S _PB1W corresponding to the standby pressure P _B1W is sequentially corrected by learning control so as to suppress the neutral tendency due to undershoot and prevent tie-up. Yes. That is, as shown by the broken line in FIG. 14, if the standby pressure P _B1W (standby pressure signal S _PB1W ) of the brake B1 is increased, the timing at which the brake B1 starts to be released after the start of sweep is delayed. On the other hand, when the standby pressure P _B1W (standby pressure signal S _PB1W ) is lowered as shown by the alternate long and _short dash line, the timing at which the brake B1 starts to be released after the start of the sweep is accelerated, so that tie-up can be prevented. . The standby _pressure signal S _PB1W is obtained by adding a learning correction value L that is sequentially updated to a predetermined reference value S _PB1WC . The reference value S _PB1WC and the learning correction value L are stored with parameters such as the type of shift and the magnitude of torque.

In this embodiment, the engagement pressure of the lockup clutch 32 is used to control the rotational speed difference N _SLP (= NE−NT) between the turbine rotational speed NT and the engine rotational speed NE to the target rotational speed difference N _SLP ^*. lock-up clutch slip control means (not shown) outputs a drive signal S _SLU for solenoid valve SLU for controlling the P _SLU is provided. The turbine rotational speed NT and the engine rotational speed NE at times t _{0 to} t ₁ in FIG. 9 are changed from the rotational speed difference N _SLP to the target rotational speed difference N _SLP ^* (for example, −50 rpm) by the drive signal S _SLU for the solenoid valve SLU. In a substantially matched state, it is gradually decreased as the vehicle decelerates. From time t ₁ to time t ₂ , the turbine rotational speed NT starts to increase with the engagement of the clutch C 1, but the increase is caused by the clutch C 1. Since the engagement pressure P _C1 is feedback-controlled, the rate of increase is substantially constant. At this time, the drive signal S _SLU for the solenoid valve _SLU is constant, so that the engine speed NE is slightly increased according to the turbine speed NT. Ascend while being delayed. Further, during the time t _{2 to} t ₃ , the turbine rotational speed NT is set to a speed corresponding to the vehicle speed V with the end of the shift, and the rotational speed difference N _SLP is again determined by feedback control using the drive signal S _SLU for the solenoid valve SLU. The target rotational speed difference N _SLP ^* is substantially matched.

The undershoot amount calculation means 150 is a reduction amount when the brake B1 as the disengagement side frictional engagement device slips and the turbine rotational speed NT decreases during the clutch-to-clutch downshift control operation (see FIG. 14). A certain undershoot amount N _US is calculated from the output shaft rotation speed N _OUT and the gear ratio γ ₄ of the gear stage before the shift (fourth speed gear stage) before the shift synchronous rotation speed N _TP (= γ ₄ × N _OUT ) and the actual turbine rotation speed NT (N _US = N _TP −NT) are sequentially calculated. The time t _{US in} FIG. 14 is the time when the brake B1 slips and the undershoot starts.

The integral value calculating means 152 integrates the undershoot amount N _US sequentially calculated by the undershoot amount calculating means 150 until the clutch C1, which is the engagement side frictional engagement device, is in the torque transmission state. and requests chute quantity integration value iN _US, the integrating means 154 for sequentially adding the successively calculated undershooting amount N _US by undershoot amount calculating means 150, so that the turbine rotational speed NT is pulled by the transfer torque of the clutch C1 , The maximum determination means 156 for determining that the undershoot amount N _US has reached the maximum (time t _{USMAX in} FIG. 14), and the added value obtained by the integration means 154 until the maximum determination is made ( and a integrated value determination means 158 for integrating value) and undershoot quantity integration value iN _US (hatched portion in FIG. 14) It is configured. The time when the undershoot amount N _US is maximized (maximum) substantially coincides with the time when the turbine rotational speed NT is minimized (minimum). Therefore, the maximum determination means 156 can determine whether the turbine rotational speed NT is minimum. good. Further, the maximum determination means 156 determines whether the maximum or the minimum from the change tendency within a predetermined time in order to prevent erroneous determination due to a temporary change in the rotational speed due to rattling of the power transmission system at the start of shifting. It is desirable to do.

Learning permission decision means 136, in the learning correction of the standby pressure signal S _PB1W for controlling said standby pressure P _B1W, determines whether conditions for permitting learning correction process is satisfied. For example, if a state whether or not the cooling water temperature T _W, etc. of the AT oil temperature T _OIL, engine 10 is stable, various sensors such as the AT oil temperature sensor 78 and the coolant temperature sensor 68 or the turbine speed sensor 76 It is determined whether or not it is operating normally, whether or not it is a single shift such as a 4 → 3 downshift. The memory state determination means 138 _performs the learning correction process in the initial state of the EPROM in which the memory such as the learning correction value L of the standby _pressure signal _SPB1W is stored, for example, the EEPROM, or after the memory is initialized (cleared). It is determined whether or not The initial state of the EEPROM is a state in which the EEPROM is mounted on the vehicle and the learning correction process is not performed, and is included in this state when the EEPROM is replaced.

For example, _when the learning correction process for the standby _pressure signal _SPB1W is executed, the learning number updating unit 140 updates and stores the learning number n by adding 1 to the previous learning number n stored in the EEPROM. . Further, in the initial state of the EEPROM or the first learning correction process after the memory is initialized (cleared), the learning number n is updated and stored so that n = 0. The learning number determination means 142 determines whether or not the normal learning process may be executed, for example, whether or not the learning number n of the learning correction process of the standby _pressure signal _SPB1W exceeds a predetermined number of times n _C. Judgment by This is because the standby _pressure signal S _PB1W is sequentially changed to an optimum value by repeatedly _performing learning correction processing. However, when the number of times of learning n is small, the undershoot amount integrated value IN _US varies due to vehicle variations. Is unavoidable, so that the learning correction value L is reflected in the next shift control operation immediately, so that the learning correction processing different from the normal learning correction processing when the number of times of learning n is large, for example, the undershoot amount integration value IN _US This is because the coefficient to be multiplied needs to be changed, and the predetermined number of times n _C is set to 2 to 5, for example.

The learning control unit 144 includes an undershoot determination unit 145, a learning correction value calculation unit 146, and a standby pressure calculation unit 148, and directly applies the engagement pressure P _{B1 of the} brake B1 that is a release side hydraulic friction engagement device. By repeatedly learning and correcting the standby pressure signal S _PB1W corresponding to the standby pressure P _B1W among the release-side hydraulic drive signal S _PB1 output to the linear solenoid valve SL3 to be controlled, a drop or tie in the turbine rotational speed NT is obtained. Sequentially change to an optimal value that does not increase. The learning control unit 144, the engagement side hydraulic driving signal S _PC1 outputted to the linear solenoid valve SL2 for controlling the engagement pressure P _C1 of the clutch C1 is engaged-side friction engagement device directly each time The learning control process is _performed only for the standby _pressure signal S _PB1W of the release side drive signal S _PB1 to prevent the turbine rotational speed NT from dropping and the tie-up from occurring.

The undershoot determination means 145 includes a target integration value IN _USU in which the undershoot amount integration value IN _US determined by the integration value determination means 158 is a first predetermined value set in advance based on a shift shock, a shift time, or the like. It is determined whether or not the value is equal to or less than an allowable integral value IN _USD that is a second predetermined value that is preset to a value lower than the first predetermined value based on a shift shock, a shift time, or the like. . The target integrated value IN _USU is an upper limit value in the region of the so-called target undershoot integrated value IN _US , and when this value is exceeded, the neutral tendency increases. Further, the allowable integral value IN _USD is a lower limit value of the so-called target undershoot amount integral value IN _US , and if it falls below this value, a tie-up tendency occurs.

When the undershoot determination unit 145 determines that the decrease in the turbine rotational speed NT is large, the learning correction value calculation unit 146 determines the learning correction value L by the fuel cut state determination unit 128 in order to avoid a neutral tendency. Calculate according to the fuel cut state. If the fuel cut state continues, a new learning correction value L _NCUT (= L _C + G) is obtained by adding a value obtained by multiplying the current learning correction value L _C to the undershoot amount integrated value IN _US by a coefficient G (gain). XIN _US ) is obtained by calculation. This gain G is a value determined in advance to reflect the undershoot amount integral value IN _US in the new learning correction value L _NCUT , and if the learning number n exceeds a predetermined number n _C set in advance. Usually learning gain G _F becomes, the gain G _K for without fast learning exceeds the predetermined number n _C. The high-speed learning gain G _K is usually learning gain G _F value larger than so as to promptly reflect the learning correction value L for the next shift control operation.

Further, when the fuel cut state is released, the standby pressure P _B1W is lower than that during normal learning, so that the neutral tendency becomes stronger and the undershoot amount NE _US of the engine speed NE becomes larger. Therefore, it is necessary to set the undershoot amount NE _US so that the fuel cut state is not canceled as few times as possible in order to improve fuel consumption. For this purpose, a new learning correction value L _NCAN (= L _C + L _NE ) is obtained by adding the learning correction value L _NE for emergency neutral avoidance learning to the current learning correction value L _C instead of the calculation used for normal learning. The emergency neutral avoidance learning correction value L _NE is obtained by setting the undershoot amount integrated value IN _US of the turbine rotational speed NT by increasing the engine rotational speed NE when the engine 10 is operated after the fuel cut state is released. Because of inaccuracy, a predetermined value determined in advance is used instead of a value obtained by multiplying the gain G by the undershoot amount integrated value IN _US as in normal learning.

The learning correction value calculation means 146 is also determined to have a tie-up tendency by the undershoot determination means 145, and the undershoot amount integrated value IN _US is set to a preset zero that appropriately takes into account the noise and accuracy of the apparatus. When it is determined that the value is equal to or smaller than the determination value, that is, a small value such as substantially zero, a learning correction value L for avoiding tie-up is calculated. When the undershoot amount integrated value IN _US is not less than or equal to the zero determination value, the undershoot amount N _US or NE _US of the turbine rotational speed NT or the engine rotational speed NE has occurred to some extent, but is close to tie-up. A new learning correction value L _{TU is} obtained by subtracting the normal learning learning correction value L _TF from the current learning correction value L _C so as to quickly reduce the standby pressure P _B1W of the brake B1 which is the release side hydraulic friction engagement device. (= L _C −L _TF ) is obtained by calculation, and when the undershoot integrated value IN _US is equal to or less than the zero judgment value, it is a tie-up state. Therefore, learning is performed once in order to quickly avoid a shift shock. the standby pressure P _B1W that subtracting the emergency tie-up avoidance learning the learning correction value L _TE from lower so as to present learning correction value L _C compared to the normal learning correction process New learning correction value _{L TT (= L C -L TE} ) and obtained by calculation. As the normal learning learning correction value _LTF or the emergency tie-up avoidance learning learning correction value _LTE , a predetermined value determined in advance is used.

Then, the standby pressure calculation means 148 _adds a new learning correction value L _NEW (L _NCUT , L _NCAN , L _TU or L _TT ) obtained by the learning correction value calculation means 146 to a predetermined reference value S _PB1WC. In addition, the next standby _pressure signal S _PB1W (= S _PB1WC + L _NEW ) of the brake B1 is calculated.

FIG. 10 shows the main part of the control operation of the electronic control unit 90, that is, the engagement of the brake B1, which is the release-side hydraulic friction engagement device, in the shift control operation of the automatic transmission 14 at the time of the clutch-to-clutch downshift during deceleration travel. FIG. 11 is a flowchart of a main routine for explaining learning correction processing of the standby pressure signal S _PB1W of the release side hydraulic drive signal S _PB1 output to the linear solenoid valve SL3 that directly controls the _combined pressure P _B1 . FIG. 12 is a subroutine of the neutral avoidance learning processing portion of FIG. 11 and FIG. 13 is a subroutine of the tie-up avoidance learning processing portion of FIG.

  In FIG. 10, in steps (hereinafter, steps are omitted) S1 and S2 corresponding to the memory state determination means 138, an EPROM in which a memory such as a learning correction value L is stored in S1, for example, an EEPROM is mounted on the vehicle. Thus, it is determined whether the learning correction process is not performed or the learning correction process is not performed after the EEPROM is replaced. In S2, the EEPROM storage is initialized (cleared). After that, it is determined whether or not the learning correction processing is not performed. If the determination of either one of S1 and S2 is affirmed, in S3 corresponding to the learning number updating means 140, the learning number n is updated so that n = 0 and stored in the EEPROM. When the determinations at S1 and S2 are both negative, S3 is not executed and the value of the learning number n stored in the EEPROM is held.

Next, in S4 corresponding to the shift state determination means 122, it is determined whether or not the driven downshift (hydraulic control) during deceleration traveling of the automatic transmission 14 is started. If the determination in S4 is negative, this routine is terminated. If the determination is affirmative, in S5 corresponding to the undershoot amount calculation means 150, the undershoot amount N _US of the turbine rotational speed NT is determined as the output shaft. The difference between the synchronous rotational speed N _TP (= γ ₄ × N _OUT ) calculated from the rotational speed N _OUT and the gear ratio γ ₄ of the gear before shifting (fourth speed gear stage) and the actual turbine rotational speed NT ( N _TP -NT). The next step S6 corresponds to the integration means 154. The undershoot amount integrated value IN _US is calculated by sequentially adding the undershoot amounts N _US sequentially obtained in S5, and S7 corresponding to the maximum determination means 156 is obtained. In this embodiment, whether or not the undershoot amount N _US has become maximum is determined based on whether or not the turbine rotational speed NT has started to increase. Then, until the turbine rotational speed NT starts to increase, in other words, until the undershoot amount N _US is substantially maximized, S5 and S6 are repeated to successively update the undershoot amount integrated value IN _US to increase the turbine rotational speed NT. Once begun, running S8 corresponding to the integral value determining section 158 determines the undershoot quantity integration value iN _US at that time as the undershoot quantity integration value iN _US during this downshift. In the case of a tie-up state in which undershoot does not occur, the undershoot amount integrated value IN _US = 0.

Thereafter, in SG1 to SG8 in FIG. 11 corresponding to S9, a new learning correction value L _NEW (L _NCUT , L _NCAN , L _TU or L L) of the standby pressure signal S _PB1W of the brake B1 which is the release side hydraulic friction engagement device. _TT ) is obtained, and this new learning correction value L _NEW is added to the reference value S _PB1WC to calculate the next standby _pressure signal S _PB1W of the brake B1. In the SG1 corresponding to the learning permission determination unit 136, that either the condition for starting the learning correction processing whether satisfied, for example, cooling water temperature T _W, etc. of the AT oil temperature T _OIL, engine 10 is stable Whether the AT oil temperature sensor 78, the cooling water temperature sensor 68, the turbine rotation speed sensor 76, or the like is operating normally, whether it is a single speed change such as a 4 → 3 down speed change, or the like. The If this SG1 is denied, this routine is terminated, but if it is affirmed, SG2 and SG3 corresponding to the undershoot determination means 145 are executed, and the undershoot amount integrated value IN obtained in S5 to S8 in SG2 It is determined whether or not _US is equal to or greater than the target integral value IN _USU . In SG3, it is determined whether or not the undershoot amount integral value IN _US is equal to or less than the allowable integral value IN _USD . If the determinations of SG2 and SG3 are negative, SG7 and subsequent steps are executed while maintaining the current learning correction value L _C in SG6. That is, if the undershoot amount integration value IN _US is between the target integration value IN _USU that is the upper limit value and the allowable integration value IN _USD that is the lower limit value, it is not necessary to change the learning correction value L. The standby _pressure signal S _PB1W for the next brake B1 may be calculated by using the current learning correction value L _C as it is and adding it to the reference value S _PB1WC .

When the above SG2 is affirmed, a new learning correction value L _NEW (L _NCUT or L _NCAN ) is obtained to avoid a neutral tendency in SN1 to SN6 in FIG. 12 corresponding to SG4, and the above SG3 is affirmed. Then, in ST1 to ST3 in FIG. 13 corresponding to SG5, a new learning correction value L _NEW (L _TU or L _TT ) is obtained in order to avoid the tie-up state.

In the neutral avoidance learning processing subroutine of FIG. 12, at the SN1 corresponding to the fuel cut state determination means 128, the engine that is output to the fuel cut device 118 by the fuel cut control means 126 during the downshift control operation during deceleration traveling. It is determined whether or not the command for shutting off the fuel supply to the _{engine 10} has been _{released. In} SN2 corresponding to the learning frequency determination means 142, the learning frequency n of the learning correction processing for the standby _pressure signal S _PB1W stored in the EEPROM is determined. Whether or not exceeds a predetermined number of times n _C , for example, 2 to 5. In SN3 to SN6 corresponding to the subsequent learning correction value calculation means 146, the learning correction value L is updated so that the standby pressure P _B1W of the brake B1 becomes high in order to avoid a neutral tendency according to the results of the SN1 and SN2. The That is, when SN1 is negated SN2 is positive, usually given learning gain G _F in SN3 for normal learning process, usually the current learning correction value L _C undershoot quantity integration value IN _US In SN6 learning gain G _F is added is multiplied value new learning correction value _{L NCUT (= L C + G} F × iN US) is calculated. If both SN1 and SN2 are negated, the variation in the undershoot integrated value IN _US due to the variation in the vehicle due to the small number of learnings n is unavoidable, so that the learning correction value L is quickly changed to the next shift. As reflected in the control operation, a high-speed learning gain G _K that is larger than the normal learning gain G _F is given in SN4, and the undershoot amount integrated value IN _{US is} added to the current learning correction value L _C in SN6. Is multiplied by the high-speed learning gain G _K, and a new learning correction value L _NCUT (= L _C + G _K × IN _US ) is calculated. Further, if the above SN1 is affirmed, the fuel cut is released because the undershoot amount NE _US of the engine 10 is large, so the fuel shot is not released as few times as possible to improve fuel consumption. The quantity N _US (NE _US ) should be used. Therefore, in the next _SN5 , a new learning correction value L _NCAN (L _NCAN = L _C + L _NE ) is calculated by adding the emergency neutral avoidance learning learning correction value L _NE to the current learning correction value L _C. . These new learning correction values L _NCUT and L _NCAN are larger than the current learning correction value L _C and have a relationship of L _C <L _NCUT <L _NCAN .

On the other hand, in the tie-up avoidance learning process subroutine of FIG. 13 corresponding to SG5 when SG3 of FIG. 11 is affirmed, first, in ST1 corresponding to the undershoot determination means 145, the undershoot amount integrated value IN _{US is used.} Is less than or equal to the zero determination value. If this ST1 is denied, undershoot has occurred to some extent but is close to tie-up, so that the standby pressure P _B1W of the brake B1 is reduced in ST3 corresponding to the learning correction value calculation means 146. The learning correction value L _TF for normal learning is subtracted from the current learning correction value L _C to calculate a new learning correction value L _TU (= L _C −L _TF ). Since the tie-up state is established when ST1 is affirmed, the learning correction value is set so that the standby pressure P _B1W is lower than the normal learning in one learning correction process in order to avoid the shift shock immediately. In ST2 corresponding to the calculation means 146, the learning correction value L _TE for emergency tie-up avoidance learning is subtracted from the current learning correction value L _C to calculate a new learning correction value L _TT (= L _C −L _TE ). . These new learning correction values L _TU and L _TT are smaller than the current learning correction value L _C and have a relationship of L _C > L _TU > L _TT .

A new learning correction value L _NEW (L _NCUT , L _NCAN , L _TU or L _TT ) is obtained in SG4 (SN1 to SN6) or SG5 (ST1 to ST3), or the current learning correction value L _C is maintained in SG6. Then, in SG7 corresponding to the learning number updating means 140, 1 is added to the previous learning number n stored in the EEPROM, and the learning number n is updated and stored.

Subsequently, in SG8 corresponding to the standby _pressure calculation means 148, a new learning correction value L _NEW (L _NCUT , L _NCAN , _{...) Obtained} by the learning correction value calculation means 146 to the reference value S _PB1WC of the standby _pressure signal S _PB1W . L _TU or L _TT ) or the current learning correction value L _C is added to calculate a standby pressure signal S _PB1W that defines the standby pressure P _B1W of the next engagement pressure P _B1 of the brake B1. Since the new learning correction value L _NEW is larger than the current learning correction value L _C because L _C <L _NCUT <L _NCAN in the case of a neutral tendency, the standby _pressure signal S _PB1W is increased accordingly. Further, in the case of a tie-up tendency, since L _C > L _TU > L _TT and smaller than the current learning correction value L _C , the standby _pressure signal S _PB1W is decreased accordingly.

FIG. 14 shows a change in the release-side hydraulic drive signal S _PB1 before and after the learning process of the standby pressure signal S _PB1W is performed in the shift control operation of the automatic transmission 14 during the downshift during the deceleration traveling of the present embodiment. The solid line is the state before the learning process is performed. In the case of a neutral tendency, the learning correction value L increases and the standby pressure signal S _PB1W increases, so the release side hydraulic drive signal S _PB1 increases as shown by the broken line, and the standby pressure P _B1W increases. Since the release timing of the brake B1 is delayed, undershoot (neutral tendency) is suppressed. On the other hand, in the case of a tie-up tendency, the learning correction value L is decreased and the standby pressure signal S _PB1W is decreased. _Therefore , the release side hydraulic drive signal S _PB1 is decreased as indicated by a one-dot chain line, and the standby pressure P _B1W Decreases and the release timing of the brake B1 is advanced, so that tie-up is suppressed.

In the present embodiment, during the clutch-to-clutch downshift during deceleration traveling, sequentially calculates an undershoot amount N _US turbine rotational speed NT (= input shaft rotational speed N _IN) by the undershoot amount calculating means 150 At the same time, until the engagement side frictional engagement device (clutch C1) is in a torque transmission state and the turbine rotational speed NT starts to increase, in other words, until the undershoot amount N _US becomes substantially maximum. determine the undershoot quantity integration value iN _US sequentially adds an undershoot amount N _US calculated by the undershoot amount calculating means 150, the release-side friction engagement device based on the undershoot amount integrated value iN _US (brake B1 The standby pressure signal S _PB1W corresponding to the standby pressure P _{B1W of} ) is corrected by learning control. Even if the turbine rotational speed NT and the output shaft rotational speed N _OUT temporarily change due to disturbance due to strikes, etc., the influence on the undershoot amount integrated value IN _US is small, and the standby _pressure signal S _PB1W based on the undershoot amount N _US Learning control is performed stably and with high accuracy.

In particular, the turbine rotational speed NT during clutch-to-clutch downshift during deceleration traveling is raised based on the transmission torque when the engagement side frictional engagement device (clutch C1) is in the torque transmission state, and the amount of undershoot is increased. Although N _US decreases, in this embodiment, until the engagement side frictional engagement device (the clutch C1) is a torque transmission state, the turbine rotational speed NT is increased by the torque transmission of the clutch C1 in particular Before the start, transmission of the engagement side frictional engagement device (clutch C1) is performed in order to obtain the undershoot amount integrated value IN _US by adding the undershoot amount N _US sequentially calculated by the undershoot amount calculating means 150. is to eliminate the influence of the torque is reduced, in the release-side friction engagement device waits pressure signal S _PB1W learning control higher accuracy of (brake B1) So divide.

In addition, since learning control is performed by obtaining the undershoot amount integrated value IN _US until the undershoot amount N _US of the turbine rotational speed NT becomes substantially maximum, the transmission torque of the engagement side frictional engagement device (clutch C1) is reduced. Reflecting the undershoot amount N _US resulting from the decrease in the engagement pressure P _B1 of the disengagement side frictional engagement device (brake B1) while reducing the influence well, the power transmission system at the start of the shift is The standby _pressure signal _SPB1W of the disengagement side frictional engagement device (brake B1) can be learned and controlled with high accuracy based on the undershoot integral value IN _US that is less affected by disturbance due to striking. That is, the engagement-side frictional engagement device (clutch C1) starts torque transmission with the engagement torque before the undershoot amount N _US of the turbine rotational speed NT becomes maximum, but the undershoot amount N _US is While the engagement torque (transmission torque) is smaller and less affected than after the maximum, the amount of data is small and the undershoot integrated value IN _US is small before the undershoot amount N _US is maximized. Therefore, it is appropriate to use the undershoot amount integrated value IN _US until the undershoot amount N _US is substantially maximized.

When a shift command for clutch-to-clutch downshift is issued, the shift hydraulic pressure control means 124 causes the engagement pressure P _B1 of the disengagement side frictional engagement device (brake B1) to be higher than the first line pressure PL1, which is the original pressure. _Is held at a predetermined standby pressure P _B1W set lower than the release start pressure of the disengagement side frictional engagement device (brake B1) for a predetermined time, and thereafter continuously decreased so as to have a constant rate of change. On the other hand, since the engagement pressure P _C1 of the engagement side frictional engagement device (clutch C1) is feedback controlled so that the turbine rotation speed NT continuously increases at a constant increase rate, the shift shock is suppressed. However, the clutch-to-clutch down shift is preferably executed.

Further, when the undershoot amount integrated value IN _{US of} the turbine rotational speed NT exceeds the target integrated value IN _USU which is the upper limit value, the standby pressure P _B1W of the disengagement side frictional engagement device (brake B1) is increased. In addition, since the standby _pressure signal _SPB1W is corrected by learning control, it is possible to reliably maintain the disengagement side frictional engagement device (brake B1) in the engaged state and suppress undershoot (neutral tendency). That is, by adjusting the sweep control start time t _B1W , which is the holding time of the standby pressure P _B1W , by learning control, it is possible to suppress the neutral tendency or prevent tie-up, but the standby pressure P _B1W is When the brake B1 slips at a low level, the brake B1 cannot be _engaged even if the sweep control start time t _B1W is increased, and undershoot cannot be suppressed.

  In the above embodiment, the clutch-to-clutch down shift control operation during the deceleration traveling of the automatic transmission 14 has been described for the 4 → 3 down shift in which the brake B1 is released and the clutch C1 is engaged. It is also possible to apply to other clutch-to-clutch downshifts such as a 3 → 2 downshift that releases and engages the brake B1.

In addition, the preset predetermined number n _C used when determining whether or not the normal learning process may be executed by the learning number determination unit 142 (step SN2) is set to 2 to 5. However, it may be suitably set according to vehicle variations. For example, if the variation of the vehicle is large, n _C may be set to about 10.

  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.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram of a laterally mounted vehicle drive device for an FF vehicle to which a transmission control device according to an embodiment of the present invention is applied. FIG. 2 is a diagram illustrating engagement and disengagement states of clutches and brakes for establishing each gear stage of the automatic transmission of FIG. 1. It is a figure explaining the input-output signal of the electronic control apparatus provided in the vehicle of the Example of FIG. It is a figure which shows an example of the shift pattern of the shift lever of FIG. It is a diagram showing an example of a relationship between the accelerator pedal operation amount Acc and the throttle valve opening theta _TH used in the throttle control performed by the electronic control unit of FIG. It is a figure which shows an example of the shift map (map) used by the shift control of the automatic transmission performed by the electronic controller of FIG. It is a figure explaining the structure of the principal part of the hydraulic control circuit of FIG. FIG. 4 is a functional block diagram illustrating a main part of a control function of the electronic control unit of FIG. 3, that is, a shift control operation of an automatic transmission. FIG. 4 is a time chart for explaining a basic control operation of a main part of the control function of the electronic control unit of FIG. The control function of the electronic control unit of FIG. 3, that is, in the shift control operation of the automatic transmission at the time of downshifting while the automatic transmission is decelerating, the standby pressure learning correction processing of the release side hydraulic friction engagement device is performed. It is a flowchart of the main routine demonstrated. It is a flowchart showing the subroutine of the learning correction value calculation process part of the flowchart of FIG. FIG. 12 is a flowchart illustrating a subroutine of a neutral avoidance learning process portion of the flowchart of FIG. 11. 12 is a flowchart showing a subroutine of a tie-up avoidance learning process portion of the flowchart of FIG. 11. Learning of the standby pressure of the release-side hydraulic friction engagement device based on the undershoot amount integral value in the main part of the control function of the electronic control unit of FIG. It is a time chart explaining control.

Explanation of symbols

14: Automatic transmission 22: Input shaft 90: Electronic control unit 124: Transmission hydraulic pressure control unit 144: Learning control unit 150: Undershoot amount calculation unit 152: Integral value calculation unit B1: Brake (release side frictional engagement device) C1 : Clutch (engagement side friction engagement device) NT: Turbine rotation speed (input shaft rotation speed) N _US : _Undershoot amount IN _US : _Undershoot amount integrated value S _PB1W : Standby pressure signal (standby pressure)

Claims (4)

Shifting of a clutch-to-clutch downshift in which a shift is achieved by releasing the release-side frictional engagement device and engaging the engagement-side frictional engagement device during deceleration traveling is performed. A control device,
An undershoot amount calculating means for sequentially calculating an undershoot amount of the input shaft rotation speed of the automatic transmission associated with the shift during the clutch-to-clutch downshift during the deceleration traveling;
An integral value calculating means for integrating the undershoot amount until the engagement side frictional engagement device is in a torque transmission state in the clutch-to-clutch downshift during the deceleration traveling, and obtaining an undershoot amount integral value;
Learning control means for correcting the engagement pressure of the disengagement side frictional engagement device based on the magnitude of the undershoot amount integral value by learning control;
The Bei example, and,
The integral value calculating means includes an integrating means for sequentially adding the undershoot amounts sequentially calculated by the undershoot amount calculating means, and a determination for determining whether or not the engagement side frictional engagement device is in a torque transmission state. And an integrated value determining means that uses the added value obtained by the integrating means before the determination is made as the integrated value of the undershoot amount. A transmission control device for a transmission. The shift control apparatus for an automatic transmission for a vehicle according to claim 1, wherein the determination unit is a maximum determination unit that determines whether or not an undershoot amount of the input shaft rotation speed is maximized. When a shift command for the clutch-to-clutch downshift is issued, the engagement pressure of the disengagement side frictional engagement device is set lower than its original pressure and higher than the disengagement start pressure of the disengagement side frictional engagement device. After holding at a predetermined standby pressure for a predetermined time, the engagement side friction is set so that the input shaft rotational speed continuously increases at a constant increase rate while continuously decreasing to a constant change rate. The shift control device for an automatic transmission for a vehicle according to claim 1 or 2, further comprising a shift hydraulic pressure control means for increasing the engagement pressure of the engagement device. The learning control means is configured to correct a learning so as to increase a standby pressure of the disengagement side frictional engagement device when the integrated value of the undershoot amount exceeds a predetermined value. 4. A transmission control device for an automatic transmission for a vehicle according to 3.

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