JP4760371B2 - Shift control device for automatic transmission - Google Patents

Description

  The present invention relates to a shift control device for an automatic transmission that increases a hydraulic pressure of an engagement-side friction engagement device to perform a downshift, and in particular, an input shaft rotation speed is in the vicinity of a synchronous rotation speed of a post-shift gear stage. The present invention relates to an improvement in technology for ending a series of shift control when it is determined continuously over a predetermined time.

An automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement devices is widely used in automobiles and the like. The technique described in Patent Document 1 is an example, and in the shift control when the hydraulic pressure of the engagement side frictional engagement device is raised to execute the downshift, the input shaft rotation speed is close to the synchronous rotation speed of the post-shift gear stage. It is known that when it is continuously determined over a predetermined time, the engagement end determination is performed and the shift control is ended. Patent Document 1 also changes the predetermined time depending on whether the downshift shift output is made before or after the start of the inertia phase of the upshift which is the first shift in the downshift of the multiple shift. Is disclosed.
JP 2004-257460 A

  By the way, when the input shaft rotational speed is synchronized with the synchronous rotational speed of the post-shift gear stage, a driving force is generated by the gear ratio of the post-shift gear stage. It is necessary to suppress changes in driving force. In order to suppress changes in driving force, the hydraulic pressure of the engagement side frictional engagement device is gradually increased for a while after the input shaft rotation speed is synchronized with the synchronous rotation speed of the post-shift gear stage, and then the hydraulic pressure is increased. It is desirable to perform shift control end processing such as increasing the pressure to the maximum pressure. For this purpose, it is sufficient to lengthen the predetermined time, but conversely, there is a problem that the time until the end of the shift becomes longer, and it is impossible to achieve both shift quality and shift time.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to continuously determine that the input shaft rotational speed is in the vicinity of the synchronous rotational speed of the post-shift gear stage for a predetermined time. In the case where the shift control end process is performed thereafter, the shift time is shortened as much as possible without impairing the shift quality due to a change in driving force or the like.

In order to achieve this object, the first invention relates to an automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement devices, and engaging-side friction engagement. In a shift control device for an automatic transmission that performs a shift control for performing a downshift by increasing the hydraulic pressure of the device, (a) based on the input shaft rotation speed of the automatic transmission. Overshoot determination means for determining whether or not an overshoot of the input shaft rotation speed with respect to the synchronous rotation speed at the post-shift gear stage occurs during the downshift; and (b) the input shaft rotation speed is the synchronization A shift control end means for ending the shift control when it is continuously determined over a predetermined time that it is in the vicinity of the rotational speed; and (c) the overshoot determination means. When it is determined that no overshoot has occurred, the predetermined time is set to the first time, and when the overshoot determination means determines that overshoot has occurred, the predetermined time is set to the first time. Determination time setting means for setting the second time shorter than one hour.
According to a second aspect of the invention, in the shift control device for the automatic transmission according to the first aspect of the invention, (a) the overshoot determining means is configured such that the input shaft rotational speed of the automatic transmission is the synchronous rotational speed + predetermined value α (where α (B) the shift control ending means determines that the input shaft rotational speed is the synchronous rotational speed ± predetermined value β (where β < The shift control is terminated when it is determined continuously within a range of α) for a predetermined time.

  In such a shift control device for an automatic transmission, the predetermined time is changed depending on whether or not an overshoot has occurred during downshift. When no overshoot has occurred, the first predetermined time is relatively long. When an overshoot occurs, the second time is shorter than the first time, so that both shift quality and shift time can be achieved.

  In other words, if no overshoot occurs, the input shaft rotation speed becomes the synchronous rotation speed due to factors other than the engagement-side friction engagement device such as engagement of the release-side friction engagement device and torque-down control of the power source. If the predetermined time is short, the shift control is performed before the hydraulic pressure of the engagement side frictional engagement device is sufficiently increased or before the release side frictional engagement device is completely released. When the engagement-side hydraulic pressure is increased to the maximum pressure at once, or when the disengagement-side hydraulic pressure is quickly reduced, the shift quality is improved. There is a risk of getting worse. For this reason, when overshoot does not occur, it is possible to prevent the transmission quality from deteriorating due to a change in driving force or the like by setting a relatively long first time as the predetermined time.

  On the other hand, when the overshoot occurs, the input shaft rotational speed is reduced to the synchronous rotational speed by the engagement of the engagement side frictional engagement device by the hydraulic control during the overshoot. Even if the predetermined time after the convergence from the overshoot to the vicinity of the synchronous rotational speed is short, the engagement-side friction engagement device is engaged and the release-side friction engagement device is released. Thus, it is possible to reliably determine that the shift has ended, and there is no possibility that a large driving force change or the like will occur when the shift control end process is performed. For this reason, when the overshoot occurs, by setting the relatively short second time as the predetermined time, the shift time can be shortened while avoiding the deterioration of the shift quality due to a change in driving force or the like.

  The present invention is preferably applied to an automatic transmission for a vehicle, and can be applied to various automatic transmissions for vehicles such as an engine-driven vehicle that generates a driving force by combustion of fuel and an electric vehicle that runs by an electric motor. . As the automatic transmission, for example, various automatic transmissions such as a planetary gear type and a parallel shaft type in which a plurality of gear stages are established in accordance with operating states of a plurality of clutches and brakes are used.

  As the friction engagement device, a hydraulic device is used. For example, the hydraulic pressure (engagement force) is changed in a predetermined change pattern by hydraulic control by a solenoid valve or the like or the action of an accumulator, or the hydraulic pressure is changed at a predetermined timing. Shift control is performed. These friction engagement devices are single-plate or multi-plate clutches and brakes, belt-type brakes, and the like that are engaged by an actuator such as a hydraulic cylinder.

  The present invention is suitably applied when downshifting is performed by changing the grip between the disengagement side frictional engagement device and the engagement side frictional engagement device. In such a case, in the power-on downshift, the input shaft rotational speed increases during the shift, so that the input shaft rotational speed is generally increased while suppressing the input shaft rotational speed from being increased by the release side hydraulic pressure, and the gear after the shift is performed. When reaching or exceeding the synchronous rotational speed of the stage, the engagement side frictional engagement device is engaged, and the hydraulic control is performed so as to reduce the release side hydraulic pressure while confirming that the input shaft rotational speed does not blow up. Done. Therefore, overshoot may occur depending on the accuracy and responsiveness of the hydraulic control, and the present invention is preferably applied to such a power-on downshift.

  In the power-off downshift, the input shaft rotation speed does not increase during shifting, so that the release side frictional engagement device is generally released early and the input shaft rotation speed is increased by the engagement of the engagement side frictional engagement device. I have to. For this reason, there is no possibility of occurrence of overshoot, and it is not always necessary to apply the present invention. However, when the present invention is applied, if the first time when no overshoot occurs is set as the predetermined time, good.

  Even with a power-off downshift, the power-off → on-downshift that changes to the power-on state in the middle of a shift will cause the disengagement side frictional engagement device to be already released at the same shift where the shift destination does not change. In the multiple shift where the tip changes, the engagement state of the disengagement side frictional engagement device is unknown, so it is desirable to release it quickly, and the input shaft rotational speed will increase quickly with power ON. Therefore, downshifting is performed while restraining the input shaft rotation speed from being increased by engaging the engagement-side frictional engagement device or torque-down control of the power source. Normally, shift control is performed on the premise of overshoot. Is called. Therefore, the present invention is preferably applied also in this case. The present invention includes a case where the downshift is performed only by the engagement control of the engagement side frictional engagement device in the state where the release side frictional engagement device is already released in such a power OFF → ON downshift. The release side frictional engagement device is not necessarily required.

  In the power-off downshift, the input shaft rotation speed may be quickly increased by the torque-up control of the power source by the electronic throttle valve opening control, etc. In this case, overshooting may occur as in the power-on downshift. Since it may generate | occur | produce, this invention is applied suitably.

  The overshoot determination means is configured to determine that an overshoot has occurred, for example, when the input shaft rotation speed exceeds the synchronized rotation speed of the post-shift gear stage + a predetermined value α. A positive value is appropriate as the predetermined value α.

  Whether or not the input shaft rotation speed has continued for a predetermined time in the vicinity of the synchronous rotation speed is determined, for example, by determining whether or not the input shaft rotation speed is within the range of the synchronous rotation speed ± predetermined value β for a predetermined time. The predetermined value β is desirably set as small as possible in consideration of an error of the rotational speed sensor and the like. When the determination is repeatedly performed at a predetermined cycle time, the number of determinations can be set as the predetermined time (first time, second time).

  The first time and the second time set by the determination time setting means are a sudden change of the engagement side frictional engagement device when the shift control end processing is performed by the shift control end means after the elapse of the time. In advance, experiments and simulations based on shift control during downshifts (hydraulic control, torque control of power source, etc.) in a sufficient amount of time that does not cause a change in driving force due to sudden release of the frictional engagement device or release side frictional engagement device Etc.

  The first time and the second time may be determined in advance, but the type of shift (from which gear stage to which gear stage), the type of friction engagement device involved in the shift, the vehicle speed The engine rotational speed, the input shaft rotational speed, the accelerator ON / OFF, the hydraulic oil temperature, etc. can be set according to the vehicle state, the driving state, and the like.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram of a 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, Via an automatic transmission 14, a differential gear device (not shown) is transmitted to drive wheels (front wheels). The engine 10 is a power source for vehicle travel, and the torque converter 12 is a fluid coupling.

  The automatic transmission 14 includes a first transmission unit 22 mainly composed of a single pinion type first planetary gear unit 20, a single pinion type second planetary gear unit 26, and a double pinion type third planetary gear unit. The second transmission unit 30, which is mainly composed of 28, is provided on the coaxial line, and the rotation of the input shaft 32 is shifted and output from the output gear 34. The input shaft 32 corresponds to the input member, and in this embodiment is the turbine shaft of the torque converter 12, and the output gear 34 corresponds to the output member, and rotates the left and right drive wheels via the differential gear device. To drive. The automatic transmission 14 is substantially symmetrical with respect to the center line, and the lower half of the center line is omitted in FIG.

  The first planetary gear unit 20 constituting the first transmission unit 22 includes three rotation elements, that is, a sun gear S1, a carrier CA1, and a ring gear R1, and the sun gear S1 is connected to the input shaft 32 to be rotationally driven. At the same time, the ring gear R1 is fixed to the case 36 through the third brake B3 so as not to rotate, whereby the carrier CA1 is decelerated and rotated with respect to the input shaft 32 as an intermediate output member. Further, the second planetary gear device 26 and the third planetary gear device 28 constituting the second transmission unit 30 are partially connected to each other to constitute four rotating elements RM1 to RM4. Specifically, the first rotating element RM1 is constituted by the sun gear S3 of the third planetary gear device 28, and the ring gear R2 of the second planetary gear device 26 and the ring gear R3 of the third planetary gear device 28 are connected to each other to perform the second rotation. The element RM2 is configured, and the carrier CA2 of the second planetary gear unit 26 and the carrier CA3 of the third planetary gear unit 28 are coupled to each other to configure the third rotating element RM3. A four-rotation element RM4 is configured. In the second planetary gear device 26 and the third planetary gear device 28, the carriers CA2 and CA3 are constituted by a common member, the ring gears R2 and R3 are constituted by a common member, and the second The pinion gear of the planetary gear device 26 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear device 28.

  The first rotating element RM1 (sun gear S3) is selectively connected to the case 36 by the first brake B1 and stopped rotating, and the second rotating element RM2 (ring gears R2, R3) is selectively selected by the second brake B2. The fourth rotation element RM4 (sun gear S2) is selectively connected to the input shaft 32 via the first clutch C1, and the second rotation element RM2 (ring gears R2, R3) is connected to the case 36 and stopped. Is selectively coupled to the input shaft 32 via the second clutch C2, and the first rotating element RM1 (sun gear S3) is integrally coupled to the carrier CA1 of the first planetary gear device 20 as an intermediate output member, The third rotation element RM3 (carriers CA2, CA3) is integrally connected to the output gear 34 to output rotation.

The clutches C1, C2 and the brakes B1, B2, B3 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic friction members that are engaged and controlled by a hydraulic actuator such as a multi-plate clutch or a band brake. 2 is engaged and released as shown in FIG. 2 by switching the hydraulic circuit by excitation or non-excitation of the linear solenoid valves SL1 to SL5 of the hydraulic control circuit 98 (see FIG. 3) or a manual valve (not shown). The state is switched, and the six forward gears and the reverse one gear are established according to the operation position (position) of the shift lever 72 (see FIG. 3). “1st” to “6th” in FIG. 2 mean the first to sixth gears for forward travel, and “Rev” is the reverse gear for the gear ratio (= input shaft rotation). (Speed N _IN / output shaft rotational speed N _OUT ) is appropriately determined by the gear ratios ρ1, ρ2, and ρ3 of the first planetary gear device 20, the second planetary gear device 26, and the third planetary gear device 28. “◯” in FIG. 2 means engagement, and a blank means release.

  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” ”And“ L ”, and in the“ P ”and“ N ”positions, neutral is established to cut off the power transmission. However, in the“ P ”position, a mechanical parking mechanism (not shown) is used to mechanically The rotation of the drive wheel is prevented.

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 requested output amount, and corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to the requested output 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 throttle valve 64 with an idle switch for detecting the fully closed state (idle state) of the electronic throttle valve 56 and the opening degree θ _TH, and the rotational speed (output shaft) of the output gear 34 corresponding to the vehicle speed V 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 the lever position (operation position) _PSH of the turbine, and detecting the turbine rotation speed NT Are provided with a turbine rotation speed sensor 76, an AT oil temperature sensor 78 for detecting an AT oil temperature T _OIL that is the temperature of the hydraulic oil in the hydraulic control circuit 98, an ignition switch 82, and the like. , Engine speed NE, intake air amount Q, intake air temperature T _A , throttle valve opening θ _TH , vehicle speed V (output shaft rotation speed N _OUT ), engine coolant temperature T _W , presence / absence of brake operation, shift lever 72 A signal representing the lever position P _SH , turbine rotational speed NT, AT oil temperature T _OIL , operation position of the ignition switch 82, etc. is supplied to the electronic control unit 90. The turbine rotational speed NT is the same as the rotational speed of the input shaft 32 (input shaft rotational speed N _IN ) that is an input member.

The hydraulic control circuit 98 includes a circuit shown in FIG. 5 regarding the shift control of the automatic transmission 14. In FIG. 5, the hydraulic oil pumped from the oil pump 40 is adjusted to a first line pressure PL <b> 1 by being regulated by a relief type first pressure regulating valve 100. The oil pump 40 is, for example, a mechanical pump that is rotationally driven by the engine 10. The first pressure regulating valve 100 regulates the first line pressure PL1 according to 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. The one-line pressure PL1 is supplied to the manual valve 104 that is interlocked with the shift lever 72. Then, when the shift lever 72 is operated to the forward drive position such as "D" position is a forward position pressure P _D of the same size from the manual valve 104 and the first line pressure PL1 is the linear solenoid valve SL1~SL5 Supplied. The linear solenoid valves SL1 to SL5 are arranged corresponding to the clutches C1 and C2 and the brakes B1 to B3, respectively, and the excitation state is controlled according to the drive signal output from the electronic control unit 90, respectively. The engagement hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 , and P _B3 are independently controlled, so that any one of the first speed gear stage “1st” to the sixth speed gear stage “6th” is controlled. Alternatively, it can be established. The linear solenoid valves SL1 to SL5 are all of a large capacity type, and the output hydraulic pressure is supplied to the clutches C1 and C2 and the brakes B1 to B3 as they are, and their engagement hydraulic pressures P _C1 , P _C2 , P _B1 , P _B2 , P Direct pressure control that directly controls _B3 is performed.

  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 follows a program stored in the ROM in advance. By performing signal processing, the respective functions of the engine control means 120 and the shift control means 130 are executed as shown in FIG. 6, and are configured separately for engine control and shift control as required. Is done.

The engine control means 120 controls the output of the engine 10, and controls the fuel injection valve 92 (see FIG. 3) for controlling the fuel injection amount in addition to controlling the opening and closing of the electronic throttle valve 56 by the throttle actuator 54. The ignition device 94 such as an igniter is controlled for ignition timing control. Control of the electronic throttle valve 56, for example, drives the throttle actuator 54 based on the actual accelerator operation amount Acc from the relationship shown in FIG. 7, the accelerator operation amount Acc increases the throttle valve opening θ _TH as increases. Further, when the engine 10 is started, cranking is performed by a starter (electric motor) 96.

The shift control means 130 performs shift control of the automatic transmission 14, and is automatically performed based on the actual throttle valve opening _θTH and the vehicle speed V from a previously stored shift diagram (shift map) shown in FIG. The gear stage to which the transmission 14 is to be shifted is determined, that is, the shift determination from the current gear stage to the shift destination gear stage is executed, and the shift output for starting the shift operation to the determined gear stage is executed. In addition, the excitation states of the linear solenoid valves SL1 to SL5 of the hydraulic control circuit 98 are set so that a shift shock such as a change in driving force does not occur and the durability of the friction material of the clutch C and the brake B is not impaired. Change continuously. As is apparent from FIG. 2, the automatic transmission 14 according to this embodiment is configured so that a continuous gear is released by a clutch-to-clutch shift in which one of the clutch C and the brake B is released and the other is engaged. Shifting of gears is performed. The solid line in FIG. 8 is an upshift line, and the broken line is a downshift line so that as the vehicle speed V decreases or the throttle valve opening _θTH increases, the gear position on the low speed side with a large gear ratio can be switched. In the figure, “1” to “6” mean the first speed gear stage “1st” to the sixth speed gear stage “6th”.

  When the shift lever 72 is operated to the “D” position, the uppermost D range (automatic shift mode) that automatically shifts using all the forward gears “1st” to “6th” is established. It is done. Further, when the shift lever 72 is operated to the “4” to “L” position, the respective shift ranges of 4, 3, 2, and L are established. In the 4th range, the shift control is performed at the forward gear stage below the 4th speed gear stage “4th”, the shift control is performed at the forward gear stage below the 3rd speed gear stage “3rd” in the 3rd range, and the shift control is carried out at the 2nd range. The speed change control is performed at the forward gear stage below the second gear stage “2nd”, and is fixed at the first gear stage “1st” in the L range. Therefore, for example, if the shift lever 72 is operated from the “D” position to the “4” position, the “3” position, or the “2” position while traveling at the sixth speed gear stage “6th” of the D range, the shift range becomes D. 4 → 3 → 2 forcibly switched from sixth gear stage “6th” to fourth gear stage “4th”, third gear stage “3rd”, second gear stage “2nd” It is downshifted and the gear stage can be changed manually.

  Such automatic or manual shift control of the automatic transmission 14 is performed by changing the engagement-side hydraulic pressure or the release-side hydraulic pressure in accordance with a predetermined change pattern, or by changing at a predetermined change timing. The control mode such as the change pattern and the change timing is determined by comprehensively considering the durability, shift response, shift shock, etc. of the clutch C and the brake B, and the accelerator pedal 50 is depressed. It is determined according to the mode of the shift, such as whether the power is in the ON state or the power OFF state where the stepping operation is not performed, or whether the next shift control is started before the end of the previous shift control, or the multiple shift or single shift. .

  In FIG. 6, the shift control means 132 at the time of downshift provided in the shift control means 130 relates to the hydraulic control of the disengagement side and engagement side frictional engagement devices (the clutch C and the brake B) at the time of downshift. A specific hydraulic control mode is determined according to the type of shift, the power ON downshift or the power OFF downshift, the multiple shift or the single shift, and the like. For example, in the case of a power-on downshift, the turbine rotation speed NT, which is the input shaft rotation speed, increases during the shift, so that the turbine rotation speed NT is controlled while suppressing the blow-up of the turbine rotation speed NT by hydraulic control of the disengagement side frictional engagement device. The shift is performed, and when the vicinity of the synchronous rotational speed of the gear stage after the shift is reached, the engagement side frictional engagement device is engaged, and the release side hydraulic pressure is lowered while confirming that the turbine rotational speed NT does not blow up. In that case, in order to prevent a shift shock and excessive blow-up, torque down control by closing control of the electronic throttle valve 56 of the engine 10 or retarding control of the ignition timing is also performed.

The time chart of FIG. 10 is an example of such a downshift at power ON. When the turbine rotational speed NT reaches the vicinity of the synchronous rotational speed ntdoki of the post-shift gear stage (time t ₃ ), the engagement side frictional engagement is performed. This is a case in which the hydraulic pressure of the apparatus is increased at a predetermined gradient, whereby the increase in the turbine rotational speed NT is stopped and held near the synchronous rotational speed ntdoki. The time chart of FIG. 11 is also an example of a downshift when the power is turned on. When the turbine rotational speed NT reaches the vicinity of the synchronous rotational speed ntdoki of the post-shift gear stage (time t ₂ ), the engagement side frictional engagement device Although the hydraulic pressure is increased at a predetermined gradient, the turbine rotational speed NT is increased as it is beyond the synchronous rotational speed ntdoki, and after overshooting a predetermined value α or more, the synchronous rotational speed is achieved by the engagement of the engagement side frictional engagement device. This is a case where it is lowered to ntdoki. In FIGS. 10 and 11, “post-shift gear stage” and “pre-shift gear stage” in the column of the turbine rotational speed NT are the synchronous rotational speeds of these gear stages, and the vehicle speed, that is, the output shaft rotational speed N. It is obtained by multiplying _OUT and the gear ratio of each gear stage. If the turbine speed NT matches the synchronous speed, it means that the gear stage is established. If it is located in the middle of the synchronous rotational speed, it means that shifting is in progress. 10 and 11, the time t ₁ is the time when the downshift gear shift command is output and the hydraulic control for the downshift is started.

  Here, FIG. 10 shows a case where the downshift is performed without causing an overshoot in which the turbine rotational speed NT greatly exceeds the synchronous rotational speed ntdoki. Is not sufficiently increased, the turbine rotational speed NT is in the vicinity of the synchronous rotational speed ntdoki due to factors other than engagement of the engagement side frictional engagement device such as engagement of the release side frictional engagement device and torque reduction control of the engine 10. There is a possibility that it is held. Therefore, the shift end determination is performed based on the time during which the turbine rotation speed NT is continuously maintained in the vicinity of the synchronous rotation speed ntdoki (within ntdoki ± β), and the engagement side hydraulic pressure is maximized at once after the shift end determination. When performing a termination process such as increasing the pressure MAX or quickly decreasing the release side hydraulic pressure to 0, if the determination time is short, for example, time A in FIG. Termination processing is performed before the hydraulic pressure rises sufficiently, or before the disengagement side frictional engagement device is completely released, and the engagement side frictional engagement device suddenly engages or the disengagement side frictional engagement device suddenly releases. As a result, a large change in driving force may occur, which may deteriorate the transmission quality. The broken lines shown in the column of control hydraulic pressure of the engagement side frictional engagement device and the column of driving force characteristics of the vehicle in FIG. is there. For this reason, when no overshoot occurs, as shown by a solid line in FIG. 10, the hydraulic pressure of the engagement side frictional engagement device is sufficiently increased and is relatively long required for the drive force to rise smoothly. By setting the time timeB as the determination time, it is possible to prevent the transmission quality from deteriorating due to a change in driving force or the like. This determination time timeB corresponds to the first time.

  On the other hand, when an overshoot occurs as shown in FIG. 11, the turbine rotational speed NT is lowered to the synchronous rotational speed ntdoki by the engagement of the engagement side frictional engagement device by the hydraulic control during the overshoot. The driving force characteristics can be optimized by controlling the engagement side hydraulic pressure, and the driving force can be raised smoothly. Therefore, when the overshoot occurs in this way, after the turbine rotational speed NT converges from the overshoot to the vicinity of the synchronous rotational speed, it is continuously held in the vicinity of the synchronous rotational speed (within ntdoki ± β). Even if the determination time when performing the shift end determination based on the remaining time is as short as, for example, time time A in FIG. 11, the engagement-side friction engagement device is engaged and the release-side friction engagement device is released. Thus, it is possible to reliably determine that the shift has ended, and there is no possibility that a large driving force change or the like will occur when the shift control end process is performed. For this reason, when overshoot occurs, the shift end time is determined using the determination time timeA shorter than the determination time timeB, so that the shift time can be shortened while avoiding deterioration of the shift quality due to a change in driving force or the like. . The determination time timeA corresponds to the second time.

  In the case of a power-off downshift, the turbine rotation speed NT does not increase during the shift, so that the release-side frictional engagement device is released early and the engagement-side frictional engagement device is engaged so that the turbine rotation speed NT. The downshift will be advanced by raising. For this reason, there is no possibility of overshoot, but the power-off downshift that changes to the power-on state during the power-off downshift will cause the frictional engagement on the disengagement side in the same shift where the shift destination will not change in the power-off to on-downshift While the device has already been released, it is desirable to release it quickly because the engagement state of the disengagement side frictional engagement device is unknown in the multiple shift in which the speed change destination is changed. Ascends quickly, and shift control is performed on the premise of overshoot as shown in FIG. In the power-off downshift, it is also possible to quickly increase the turbine rotational speed NT by the torque-up control of the engine 10 by the opening control of the electronic throttle valve 56. In this case, the downshift is performed quickly. There is a possibility that overshoot occurs as shown in FIG.

The downshift transmission control means 132 according to the present embodiment performs the end process by performing the end-of-shift determination according to the presence or absence of the overshoot in this way, the overshoot determination means 134 shown in FIG. Number setting means 136 and shift control end means 138 are provided, and signal processing is performed according to the flowchart of FIG. Step S3 in FIG. 9 corresponds to the overshoot determining means 134, step S4~S10 corresponds to shift control ending means 138, step S6, the portion for setting the constant N _A or N _B in S9 is determined frequency setter 136 It corresponds to. The determination number setting means 136 corresponds to a determination time setting means.

In step S1 of FIG. 9, it is determined whether or not a downshift command for downshifting is output in accordance with the shift map of FIG. 8 or the shift operation by the shift lever 72. S2 is executed. In step S2, the hydraulic control of the engagement side hydraulic pressure and the release side hydraulic pressure is performed according to the type of shift, the power ON downshift or the power OFF downshift, the multiple shift or the single shift, and the like. In addition, torque down control or torque up control of the engine 12 is performed as necessary. The time t ₁ in FIGS. 10 and 11 is the time when the determination in step S1 is YES (positive) and the hydraulic control or the like in step S2 is started.

In step S3, it is determined whether or not the turbine rotational speed NT exceeds an overshoot determination value (ntdoki + α) that is higher than the synchronous rotational speed ntdoki of the post-shift gear stage by a predetermined value α. If NT> ntdoki + α is satisfied. An overshoot determination that an overshoot has occurred is performed. When the overshoot determination is made, steps S4 to S6 are executed to determine the shift end, and when the overshoot determination is not made, steps S7 to S9 are executed to determine the shift end. This overshoot determination is retained as a history during a series of downshift controls. Once the overshoot determination is made, the determination in step S3 is YES (positive) even if NT ≦ ntdoki + α thereafter. Step S4 and subsequent steps are executed. A predetermined value (for example, about 50 rpm) is predetermined as the predetermined value α. Time t ₃ in FIG. 11, taken determination in step S3 is the YES (affirmative), it is time to process when step S4 following overshoot is started.

In step S4, which is executed when the overshoot determination is made, whether the turbine rotational speed NT is in the vicinity of the synchronous rotational speed ntdoki, specifically, whether the synchronous condition of the following equation (1) is satisfied. Judging. Β in the equation (1) is a constant determined based on the detection error of the turbine rotational speed sensor 76, and determines whether or not the turbine rotational speed NT is substantially maintained at the synchronous rotational speed ntdoki. Then, when the synchronization determination satisfying the synchronization condition of the expression (1) is made, step S5 and subsequent steps are executed. At time t _{4 in} FIG. 11, the overshoot turbine rotational speed NT decreases due to the engagement of the engagement side frictional engagement device, and the synchronization condition of the equation (1) is satisfied, and the determination in step S4 is YES. (Yes)
ntdoki + β>NT> ntdoki-β (1)

In step S5, the counter adds 1 to the count value of Sftendcount, in step S6, it is determined whether the count value of the counter Sftendcount exceeds a predetermined constant N _A. The initial value of the counter sftendcount is 0 and is reset when the determination in step S4 or S7 is NO (negative), and the synchronization determination in which the determination in step S4 is YES (positive) is continued. In other words, the number of determinations that satisfy the synchronization condition of equation (1) continuously is counted. The flowchart of FIG. 9 is repeatedly executed at a predetermined cycle time, and the count value of the counter sftendcount corresponds to a duration time that satisfies the synchronization condition of equation (1). Also, the constant N _A, the number of cycles corresponding to the determination time TimeA, step S6 is substantially (1) of the duration to satisfy the synchronization condition determining whether exceeds the determination time TimeA become. This constant N _A That determination time timeA may previously fixed value is defined, but in this embodiment adapted to be set in accordance with the (shift or to any gear from which gear) shift type ing.

Then, the count value of the counter sftendcount exceeds the constant N _A, the determination in step S6 is to YES (the YES), carrying out the termination process in step S10. In step S6, it is determined whether or not the downshift has substantially ended. In the end process in step S10, the engagement-side hydraulic pressure is increased to the maximum pressure MAX at once, and the disengagement-side hydraulic pressure is quickly increased. Until the hydraulic pressure control during downshift is finished. Further, when the torque down control or the torque up control of the engine 10 is performed, the torque control is also ended. Time t ₅ in FIG. 11 is a time determination in step S6 becomes to YES (the YES), as compared to the case where the shift end determination (shift end determination time t ₆₎ on the basis of the determination time TimeB, determination The shift time is shortened by the difference between the times timeB and timeA.

On the other hand, if the determination in step S3 is NO (No), that is, if the overshoot determination has not been made, steps S7 to S9 are executed to determine whether to complete the shift. Steps S7 and S8 are the same as steps S4 and S5, and a synchronization determination is made based on whether or not the synchronization condition of equation (1) is satisfied. If the synchronization condition is satisfied, the count value of the counter sftendcount is set. Add one. In step S9, the count value of the counter Sftendcount, that is, the number of determinations that satisfies continuously synchronization condition, it is determined whether more than a predetermined constant N _B. Constant N _B is the number of cycles corresponding to the determination time TimeB, step S9, depending whether the duration that satisfies substantially (1) of the synchronization condition exceeds the determination time TimeB, the shift end determination Will do. This constant N _B That determination time timeB may previously fixed value is defined, but in this embodiment adapted to be set in accordance with the (shift or to any gear from which gear) shift type ing. Time t ₂ in Figure 10, (1) so as to satisfy the synchronization condition, a time for determination of the step S7 becomes to YES (the positive).

Then, the count value of the counter sftendcount exceeds the constant N _B, the determination in step S9 is to YES (the YES), executes the step S10, along with increasing the engagement hydraulic pressure to stretch the maximum pressure MAX, the disengagement hydraulic pressure Is immediately terminated. Time t _{5 in} FIG. 10 is the time when the determination in step S9 is YES (affirmative). In that case, the determination time timeB corresponding to the constant N _B is a sufficient time required for hydraulic pressure is sufficiently increased driving force of the engagement side frictional engagement device rises smoothly, from the determination time timeA Is sufficiently long, it is possible to prevent the shift quality from deteriorating due to a large change in driving force or the like due to the end processing. In contrast, when the shifting completion determination of the constants N _A That determination time step S9 based on TimeA, will be the shift end determination at time t ₄ is performed, the engagement due to termination processing as indicated by a broken line if The driving force suddenly changes due to a sudden increase in the engagement hydraulic pressure of the side frictional engagement device, and the speed change quality deteriorates.

As described above, according to the transmission control apparatus of the present embodiment, it is determined whether or not an overshoot has occurred in step S3. If an overshoot has occurred, a constant corresponding to a relatively short determination time timeA in step S6. shift end determination is performed using N _a, since the shift end determination is performed using a constant N _B corresponding to a long determination time timeB than determination time timeA in step S9 if the overshoot does not occur Thus, both the shift quality and the shift time can be achieved, and the shift time when the overshoot occurs can be shortened without impairing the shift quality.

That is, when no overshoot occurs as shown in FIG. 10, the turbine rotation is caused by factors other than the engagement side frictional engagement device, such as engagement of the release side frictional engagement device and torque reduction control of the engine 10, for example. Since the speed NT may be held in the vicinity of the synchronous rotational speed ntdoki, if the determination time timeB is as short as timeA, before the hydraulic pressure of the engagement side frictional engagement device is sufficiently increased, or the release side friction An end process of the shift control is performed before the engagement device is completely released. In the end process, the engagement side hydraulic pressure is increased to the maximum pressure MAX at once, or the release side hydraulic pressure is quickly decreased. In this case, there is a risk that the quality of the shift may deteriorate due to a large change in driving force. On the other hand, in this embodiment, as the determination time timeB (constant N _B ), a sufficient time required for the hydraulic pressure of the engagement side frictional engagement device to sufficiently increase and the driving force to rise smoothly is determined. Therefore, it is possible to prevent the shift quality from deteriorating due to a change in driving force or the like during the end process.

  On the other hand, when an overshoot as shown in FIG. 11 occurs, the turbine rotational speed NT is lowered to the synchronous rotational speed ntdoki by the engagement of the engagement side frictional engagement device by the hydraulic control during the overshoot. The driving force characteristic can be optimized by controlling the hydraulic pressure, and in this embodiment, the driving force can be smoothly increased. For this reason, even if the determination time timeA after the convergence from the overshoot to the vicinity of the synchronous rotational speed ntdoki is short, the engagement-side friction engagement device is engaged and the release-side friction engagement device is released, and the shift is completed. It is possible to reliably determine whether the shift control has been completed, and there is no fear of a large change in driving force when performing the shift control end process, and the shift end determination is performed at the determination time timeB when no overshoot has occurred. The shift time is shortened compared to the case. When the shift time is shortened in this way, the next shift can be started quickly by multiple shifts or the like, and the entire shift required time until a desired driving force can be obtained is shortened.

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

1 is a schematic diagram of a vehicle drive device to which 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. FIG. 4 is a circuit diagram illustrating a configuration of a portion related to shift control of the automatic transmission in the hydraulic control circuit of FIG. 3. It is a block diagram explaining the function with which the electronic control apparatus of FIG. 3 is provided. Is a diagram showing an example of a relationship between the accelerator operation amount Acc and the throttle valve opening theta _TH used in the throttle control performed by the engine 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 shift control means of FIG. FIG. 7 is a flowchart for specifically explaining a portion related to a shift end determination in the signal processing performed by the downshift shift control means of FIG. 6. FIG. 10 is an example of a time chart when a shift end determination is made according to the flowchart of FIG. 9 when no overshoot occurs. 10 is an example of a time chart when a shift end determination is made according to the flowchart of FIG. 9 when an overshoot occurs.

Explanation of symbols

  14: Automatic transmission 90: Electronic control device 130: Shift control means 134: Overshoot determination means 136: Determination number setting means (determination time setting means) 138: Shift control end means NT: Turbine rotation speed (input shaft rotation speed) C1, C2: Clutch (friction engagement device) B1 to B3: Brake (friction engagement device) timeA: Determination time (second time) timeB: Determination time (first time) ntdoki: Synchronous rotation speed of gear stage after shifting

Claims (2)

The present invention relates to an automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement devices, and performing a downshift by increasing the hydraulic pressure of the engagement side friction engagement device. , In a shift control device for an automatic transmission that performs shift control for executing the downshift,
Overshoot determining means for determining whether or not an overshoot of the input shaft rotation speed with respect to the synchronous rotation speed in the post-shift gear stage occurs during the downshift based on the input shaft rotation speed of the automatic transmission; ,
Shift control ending means for ending the shift control when it is continuously determined over a predetermined time that the input shaft rotation speed is in the vicinity of the synchronous rotation speed;
When the overshoot determining means determines that no overshoot has occurred, the predetermined time is set to the first time, and when the overshoot determining means determines that an overshoot has occurred Determination time setting means for setting the predetermined time to a second time shorter than the first time;
A shift control apparatus for an automatic transmission, comprising: The overshoot determination means determines that an overshoot has occurred when the input shaft rotation speed of the automatic transmission exceeds the synchronous rotation speed + a predetermined value α (where α is a positive value),
The shift control end means performs the shift control when it is continuously determined over a predetermined time that the input shaft rotation speed is within the range of the synchronous rotation speed ± predetermined value β (where β <α). Is to end
The shift control apparatus for an automatic transmission according to claim 1.

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