JP6673252B2 - Control device for stepped automatic transmission - Google Patents

Description

  The present invention relates to a control device for a stepped automatic transmission, and more particularly to a control device for a stepped automatic transmission that executes a shift based on target shift characteristics.

  2. Description of the Related Art Conventionally, in a stepped automatic transmission in which a shift gear is formed by changing a plurality of friction engagement elements, hydraulic control of the friction engagement elements is performed so that actual shift characteristics match target shift characteristics. ing. More specifically, the target shift characteristic is usually the input shaft rotation speed corresponding to the shift progress degree ((input shaft rotation speed-pre-shift synchronization rotation speed) / (post-shift synchronization rotation speed-pre-shift synchronization rotation speed)). And the oil pressure control of the friction engagement element is performed such that the actual gradient of the input shaft rotation speed matches the target gradient. In such a target shift characteristic, a relatively small target gradient # 1 is considered at the beginning of a shift (when the shift progress is small) in consideration of a hydraulic response delay, and a relatively small target gradient # 1 during a middle shift (when the shift progress is medium). In general, a relatively large target gradient # 3 is set at the end of the shift (when the degree of progress of the shift is large), and a relatively small target gradient # 3 is set at the end of the shift.

  By the way, the target shift characteristic is set to decrease the input shaft rotation speed in the upshift, while it is set to increase the input shaft rotation speed in the downshift. When the friction coefficient of the engagement side becomes small, there is a problem that at the time of a downshift, the release timing of the release side frictional engagement element is too early in comparison with the engagement timing of the engagement side frictional engagement element, and a blow-up occurs.

  Therefore, for example, in Japanese Patent Application Laid-Open No. H11-157, when an upshift in the input shaft rotation speed is detected during a downshift, the target shift time is corrected so as to be longer, thereby eliminating the upshift state in the next shift. A machine control device is disclosed.

JP-A-11-210874

By the way, in the shift control based on the target shift characteristics as described above, if a multiple shift that switches from an upshift to a downshift or from a downshift to an upshift is performed in the initial stage of the shift, the time required for the shift to be completed is required. There is a problem that it becomes longer than this. In the following description, for convenience, n-speed (n is a positive integer) → n + 1-speed upshift and n + 1-speed → n-speed downshift, and there is no change in vehicle speed during shifting, and It is assumed that the pre-shift synchronous rotational speed ω _BU and the post-shift synchronous rotational speed ω _{AD in} downshifting are the same.

For example, at the time of shift start upshift, the transmission input shaft rotational speed, after reduction with a relatively small target slope △ U1 from the pre-shift synchronizing speed omega _BU, relatively a large target slope △ U2 in the transmission middle A target shift characteristic that decreases is set. Then, in the middle of the shift in the upshift, in other words, when the input shaft rotation speed drops to some extent from the pre-shift synchronization rotation speed _ωBU , the shift to the downshift is performed and the new target shift characteristic is set. Since there is a difference between the rotation speed and the post-shift synchronous rotation speed ω _AD , which corresponds to the middle stage of the shift in the downshift, the shift after the update setting is started with a relatively large target gradient ΔD2. Therefore, in the subsequent downshift, after the input shaft rotation speed increases with a relatively large target gradient △ D2 in the middle of the shift, and after the shift, the input shaft rotation speed increases with a relatively small target gradient △ D3. Since the hydraulic pressure control is performed so as to reach the rotation speed ω _AD , there is no problem that the time required for completing the gear shift becomes unnecessarily long.

On the other hand, at the beginning of the upshift, in other words, when the input shaft rotation speed has hardly decreased from the pre-shift synchronization rotation speed ω _BU , the shift to the downshift is performed and a new target shift characteristic is set. Since the difference between the rotation speed and the post-shift synchronous rotation speed ω _AD is small and the end of the shift in the downshift is reached, the shift after the update setting is started with a relatively small target gradient ΔD3 toward the engagement completion. become.

  In addition, even when the mode is switched from the upshift to the downshift, the shift may progress in the upshift direction (the shift progress degree in the downshift decreases) due to a delay in the hydraulic response of the friction engagement element. Even if such a decrease in the shift progress rate occurs, when the downshift is switched at the beginning of the upshift, only the relatively small target gradient △ D3 is buffered (stored), so that the input shaft rotation speed is reduced. There is a problem that the speed does not rise easily and the time required for the completion of the shift becomes longer than necessary.

  In particular, as in the above-mentioned Patent Document 1, when a rise in the input shaft rotation speed is detected during a downshift, correction is performed so that the target shift time is lengthened. If executed, there is a possibility that the shift time will be longer. In addition, the above-mentioned problem can also occur when switching to an upshift at the beginning of a downshift.

  SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to provide a control device for a stepped automatic transmission that executes a shift based on a target shift characteristic, after a target shift characteristic is updated and set. It is an object of the present invention to provide a technique for suppressing an increase in time required for completing a shift even when a shift is performed.

  In order to achieve the above object, in the control device for a stepped automatic transmission according to the present invention, not only is the target shift characteristic updated when multiple shifts are performed, but also after the target shift characteristic is updated. Even in the case of a large backward movement, the target shift characteristic is updated and set so as to match the actual input shaft rotation speed.

  More specifically, the present invention controls the hydraulic pressure of a plurality of frictional engagement elements that form a shift speed based on a target shift characteristic including a target gradient of the transmission input shaft rotation speed, thereby performing a shift. It is intended for the control device of a stepped automatic transmission.

  The control device includes a characteristic updating unit configured to update and set a target shift characteristic based on a vehicle state at the start of a shift and at the time of switching from an upshift to a downshift or a downshift to an upshift. A characteristic holding unit that holds the target shift characteristic updated and set by the update unit, and a target shift characteristic that is updated and set by the characteristic update unit. Execution means for executing the shift of the vehicle, wherein the characteristic updating means updates and sets the target shift characteristic even when the shift progress degree decreases by a predetermined value or more after updating the target shift characteristic. It is characterized by having been done.

  In the following, for convenience of explanation, it is assumed that an upshift from the nth speed to the n + 1th speed and a downshift from the n + 1th speed to the nth speed and that there is no change in the vehicle speed during the shifting are performed. It is not limited to the case.

  According to this configuration, the target shift characteristic is updated when switching from an upshift to a downshift or from a downshift to an upshift. Therefore, even when a multiplex shift is performed after the start of a shift, the target shift characteristic is determined according to the shift mode after the shift. Can be executed.

  For example, when the shift is switched to the downshift after the middle of the shift in the upshift (for example, the shift progress 0.5), the target shift characteristic in the downshift is updated and the shift progress (0.5) at the time of the update setting is set. The downshift is performed based on the subsequent target shift characteristics. Thus, for example, after the input shaft rotation speed increases at a relatively large target gradient in the middle of a shift, the downshift is performed so as to reach the post-shift synchronous rotation speed while increasing at a relatively small target gradient at the end of the shift. Since the shift is performed, it is possible to prevent the time required until the shift is completed from becoming unnecessarily long.

  On the other hand, for example, when the downshift is switched at the beginning of the upshift (for example, the shift progress degree is 0.1), the update is set to the target shift characteristic in the downshift, and after the shift progress degree (0.9) at the time of the update setting. The downshift is executed based on the target shift characteristic of. In general, a relatively small target gradient is set at the end of the shift in order to suppress the blow-up. However, the downshift is executed based on the target shift characteristic after the shift progress degree of 0.9. In such a case, the hydraulic control of the friction engagement element is performed based on the relatively small target gradient.

  Here, even when switching from the upshift to the downshift, the shift may progress in the upshift direction (the shift progress decreases) due to a delay in the hydraulic response of the friction engagement element. If the time required to complete the shift does not become unnecessarily long even with a small and relatively small target gradient, the updated target shift characteristic is maintained.

  On the other hand, if the shift progress is significantly reduced and the shift progress decreases by a predetermined value or more (for example, the shift progress to 0.5) after the target shift characteristic is updated and set, the target shift characteristic is updated and set. The downshift is executed based on the target shift characteristics after the shift progress degree (0.5) at the time of the update setting. As a result, a relatively large target gradient corresponding to the reduced input shaft rotation speed is buffered, so that the input shaft rotation speed reduced due to the hydraulic response delay can be increased with a relatively large target gradient.

  As described above, according to the present invention, it is possible to prevent the time required for the completion of the shift from becoming unnecessarily long regardless of the stage at which the multiple shift is performed.

  Further, in the present invention, even when multiple shifts are performed a plurality of times in one shift, the target shift characteristic is updated and set when the shift progression decreases by a predetermined value or more after the target shift characteristic is updated and set. In addition, the time required until the shift is completed can be optimized.

  As described above, according to the control device for a stepped automatic transmission according to the present invention, multiple shifts for switching from upshift to downshift or from downshift to upshift are performed after the target shift characteristic is updated. Even in such a case, it is possible to suppress an increase in the time required until the shift is completed.

1 is a schematic configuration diagram schematically illustrating a vehicle on which an automatic transmission according to the present invention is mounted. FIG. 2 is a skeleton view schematically showing the configurations of a torque converter and an automatic transmission. 3 is an engagement table showing an engagement state or a release state of a friction engagement element for each gear position in the automatic transmission. FIG. 2 is a block diagram illustrating a configuration of a control system of the vehicle. 4 is a flowchart illustrating an example of target shift characteristic update control executed by an ECU. 6 is a timing chart illustrating an example of target shift characteristic update control. FIG. 4 is a diagram schematically illustrating target shift characteristics and target shift characteristics during multiple shifts.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram schematically showing a vehicle 10 on which the automatic transmission 3 according to the present embodiment is mounted. As shown in FIG. 1, the vehicle 10 includes an engine 1, a torque converter 2, an automatic transmission 3, a hydraulic control device 4, and an ECU 5. The vehicle 10 is, for example, an FF (front engine / front drive) system, in which the output of the engine 1 is transmitted to a differential device 6 via a torque converter 2 and an automatic transmission 3, and left and right drive wheels (front wheels) 7. Is to be distributed.

-Engine-
The engine 1 is a driving power source for traveling, and is, for example, a multi-cylinder gasoline engine. The operating state of the engine 1 can be controlled by a throttle opening (amount of intake air) of a throttle valve (not shown), a fuel injection amount, an ignition timing, and the like.

-Torque converter-
FIG. 2 is a skeleton view schematically showing the configurations of the torque converter 2 and the automatic transmission 3. In FIG. 2, the lower half of the rotational center axis of the torque converter 2 and the automatic transmission 3 is omitted, and only the upper half is shown. As shown in FIG. 2, the torque converter 2 includes a pump impeller 21 connected to a crankshaft 1a which is an output shaft of the engine 1, a turbine runner 22 connected to the automatic transmission 3, and a stator having a torque amplifying function. 23 and a lock-up clutch 24 for directly connecting the engine 1 and the automatic transmission 3.

-Automatic transmission-
The automatic transmission 3 is provided in a power transmission path between the engine 1 and the drive wheels 7 and forms a plurality of shift speeds to shift the rotation of the input shaft 3a and output the speed to the output shaft 3b. It is configured as a step-type automatic transmission. In the automatic transmission 3, the input shaft 3a is connected to the turbine runner 22 of the torque converter 2, and the output shaft 3b is connected to the drive wheels 7 via the differential device 6 and the like.

  The automatic transmission 3 includes a first transmission portion 31 mainly including a first planetary gear device 31a, and a second transmission portion 32 mainly including a second planetary gear device 32a and a third planetary gear device 32b. , A first clutch C1 to a fourth clutch C4, a first brake B1, a second brake B2, and the like.

  The first planetary gear unit 31a constituting the first transmission unit 31 is a double pinion type planetary gear mechanism, and supports a sun gear S1, a plurality of pairs of pinion gears P1 meshing with each other, and these pinion gears P1 so as to be able to rotate and revolve. And a ring gear R1 that meshes with the sun gear S1 via a pinion gear P1.

  The planetary carrier CA1 is connected to the input shaft 3a and rotates integrally with the input shaft 3a. The sun gear S1 is fixed to the transmission case 30 so as not to rotate. The ring gear R <b> 1 functions as an intermediate output member, is reduced in speed with respect to the input shaft 3 a, and transmits the reduced rotation to the second transmission portion 32.

  The second planetary gear unit 32a constituting the second transmission unit 32 is a single pinion type planetary gear mechanism, and includes a sun gear S2, a pinion gear P2, and a planetary carrier RCA that supports the pinion gear P2 so as to be able to rotate and revolve. And a ring gear RR that meshes with the sun gear S2 via the pinion gear P2.

  The third planetary gear device 32b that constitutes the second transmission portion 32 is a double pinion type planetary gear mechanism, and includes a sun gear S3, a plurality of pairs of pinion gears P2 and pinion gears P3 that mesh with each other, and the pinion gears P2 and P2 and the pinion gears. There is provided a planetary carrier RCA that supports P3 so that it can rotate and revolve, and a ring gear RR that meshes with the sun gear S3 via the pinion gear P2 and the pinion gear P3. The pinion gear P2, the planetary carrier RCA, and the ring gear RR are shared by the second planetary gear unit 32a and the third planetary gear unit 32b.

  Sun gear S2 is selectively connected to transmission case 30 by first brake B1. The sun gear S2 is selectively connected to the ring gear R1 via the third clutch C3. Further, the sun gear S2 is selectively connected to the planetary carrier CA1 via the fourth clutch C4. The sun gear S3 is selectively connected to the ring gear R1 via the first clutch C1. The planetary carrier RCA is selectively connected to the transmission case 30 by the second brake B2. Further, the planetary carrier RCA is selectively connected to the input shaft 3a via the second clutch C2. The ring gear RR is connected to the output shaft 3b, and rotates integrally with the output shaft 3b.

  Each of the first clutch C1 to the fourth clutch C4, the first brake B1, and the second brake B2 is a friction engagement element that is frictionally engaged by a hydraulic actuator, and is controlled by the hydraulic control device 4 and the ECU 5.

  FIG. 3 is an engagement table showing an engaged state or a released state of the first clutch C1 to the fourth clutch C4, the first brake B1, and the second brake B2 for each gear position. In the engagement table shown in FIG. 3, a circle indicates an "engaged state" and a blank indicates a "disengaged state."

  As shown in FIG. 3, in the automatic transmission 3 of this example, the gear ratio (the rotation speed of the input shaft 3a / the rotation speed of the output shaft 3b) is obtained by engaging the first clutch C1 and the second brake B2. Is the largest (1st). The second shift speed (2nd) is established by engaging the first clutch C1 and the first brake B1.

  The third shift stage (3rd) is established by engaging the first clutch C1 and the third clutch C3, and the fourth shift stage (3rd) is established by engaging the first clutch C1 and the fourth clutch C4. 4th) holds.

  The fifth shift speed (5th) is established by engaging the first clutch C1 and the second clutch C2, and the sixth shift speed (5th) is established by engaging the second clutch C2 and the fourth clutch C4. 6th) holds.

  The seventh shift stage (7th) is established by engaging the second clutch C2 and the third clutch C3, and the eighth shift stage (7th) is established by engaging the second clutch C2 and the first brake B1. 8th) holds. The reverse (Rev) is established by engaging the third clutch C3 and the second brake B2.

−Hydraulic control device−
The hydraulic control device 4 controls engagement and release of a plurality of friction engagement elements (first to fourth clutches C1 to C4 and first and second brakes B1 and B2) of the automatic transmission 3. The hydraulic control device 4 also has a function of controlling the lock-up clutch 24 of the torque converter 2. The hydraulic control device 4 includes a hydraulic actuator (not shown) for each friction engagement element of the automatic transmission 3 and a linear solenoid valve (not shown) for supplying a control hydraulic pressure to each hydraulic actuator. Have.

-ECU-
The ECU (control device) 5 is configured to perform operation control of the engine 1 and shift control of the automatic transmission 3. Specifically, as shown in FIG. 4, the ECU 5 includes a CPU 51, a ROM 52, a RAM 53, a backup RAM 54, an input interface 55, and an output interface 56.

  The CPU 51 executes arithmetic processing based on various control programs and maps stored in the ROM 52. The ROM 52 stores various control programs, maps referred to when the various control programs are executed, and the like. The RAM 53 is a memory for temporarily storing the calculation result by the CPU 51, the detection result of each sensor, and the like. The backup RAM 54 is a non-volatile memory that stores data and the like to be stored when the ignition is turned off.

  The input interface 55 is connected to a crank position sensor 81, an input shaft rotation speed sensor 82, an output shaft rotation speed sensor 83, an accelerator opening sensor 84, a throttle opening sensor 85, an air flow meter 86, and the like.

  The crank position sensor 81 is provided to calculate the rotation speed of the engine 1. The input shaft rotation speed sensor 82 is provided to calculate the rotation speed ωi (= turbine rotation speed ωt) of the input shaft 3a of the automatic transmission 3. The output shaft rotation speed sensor 83 is provided for calculating the rotation speed ωo of the output shaft 3b of the automatic transmission 3. The vehicle speed v can be calculated from the rotation speed ωo of the output shaft 3b. The accelerator opening sensor 84 is provided for detecting an accelerator opening, which is an amount of depression (an operation amount) of an accelerator pedal (not shown). The throttle opening sensor 85 is provided for detecting the throttle opening of the throttle valve. The air flow meter 86 is provided for detecting an intake air amount of the engine 1.

  The output interface 56 is connected to the injector 91, the igniter 92, the throttle motor 93, the hydraulic control device 4, and the like. The injector 91 is a fuel injection valve, and is capable of adjusting a fuel injection amount. The igniter 92 is provided for adjusting the ignition timing by a spark plug (not shown). The throttle motor 93 is provided for adjusting the throttle opening of the throttle valve.

  The ECU 5 is configured to be able to control the operating state of the engine 1 by controlling the throttle opening, the fuel injection amount, the ignition timing, and the like based on the detection result of each sensor and the like. Further, the ECU 5 is configured to be able to execute the shift control of the automatic transmission 3 and the control of the lock-up clutch 24 of the torque converter 2 by controlling the hydraulic control device 4.

  In the shift control by the ECU 5, for example, a target shift gear is set based on a shift map using the vehicle speed v and the accelerator opening as parameters. Note that the shift map is a map in which a plurality of regions for determining an appropriate shift gear (shift gears 1st to 8th for optimum efficiency) are set in accordance with the vehicle speed v and the accelerator opening. It is stored in the ROM 52 of the ECU 5. A plurality of shift lines (upshift lines and downshift lines for defining each of the first to eighth shift regions) are defined in the shift map.

  Then, the ECU 5 controls the first to fourth clutches C1 through the hydraulic control device 4 based on the target shift characteristics including the target gradient of the input shaft rotation speed ωi such that the current shift speed is the target shift speed.変 速 C4 and the hydraulic pressure of the first and second brakes B1 and B2 are controlled to perform a shift. When performing a shift based on such target shift characteristics, the ECU 5 is configured to perform a target shift characteristic update control, which will be described later, so as to optimize the time required until the shift is completed.

-Shift control using shift model-
Before describing the target shift characteristic update control, an outline of shift control for determining a control operation amount in the automatic transmission 3 that matches an actual shift characteristic with the target shift characteristic will be described.

  As a general shift control, for example, based on a control map predetermined by adaptation while evaluating whether a shift shock, a shift time, and the like are appropriate in an actual vehicle, based on a control map predetermined during adaptation, There is a method of determining a torque capacity (or a hydraulic pressure command value) and executing a shift. In the method using the control map, it is necessary to prepare a large number of control maps according to a combination of a shift pattern such as a power-on downshift or a power-off upshift and a shift gear position before and after the shift. Therefore, as the number of gears of the stepped automatic transmission increases, the adaptation operation requires more labor.

  Therefore, in the present embodiment, a method of performing a shift using a shift model that determines a control operation amount that matches an actual shift characteristic with a target shift characteristic, instead of a method using a control map, as a shift control. Has adopted. The target shift characteristic is a target value of an element (for example, a shift time, a rotation speed gradient, a driving force, and the like) that determines a change mode to be realized at the time of shifting. The control operation amount is a required value of an element (engine torque, clutch torque, or the like) operated on the control target.

  Hereinafter, shift control using the shift model will be described. The equation of motion during shifting is represented by the following equations (1) and (2).

  Equations (1) and (2) are derived from equations of motion of the mutually connected rotating elements constituting the automatic transmission 3 and relational expressions in the planetary gear device constituting the automatic transmission 3. Things. The equation of motion of each rotating element is based on the torque expressed by the product of the inertia of each rotating element and the rate of change of the rotational speed over time, which is obtained by rotating each of the three members of the planetary gear set and the members on both sides of the friction engagement element. It is an equation of motion defined by a torque acting on a member related to an element. Further, the relational expression in the planetary gear device is a relational expression that defines the relationship between the torque and the relationship between the rotational speed and the time rate of change in the three members of the planetary gear device using the gear ratio of the planetary gear device.

  In the equations (1) and (2), dωt / dt is a time derivative of the turbine rotation speed ωt (that is, the input shaft rotation speed ωi of the automatic transmission 3), that is, a time change rate, and the rotating member on the input shaft 3a side Represents the acceleration (angular acceleration, hereinafter referred to as input shaft acceleration) of the input shaft 3a as the amount of change in speed. This input shaft acceleration dωt / dt corresponds to the gradient of the input shaft rotation speed ωi in the present invention. dωo / dt is a time change rate of the output shaft rotation speed ωo of the automatic transmission 3 and represents the output shaft acceleration. Tt represents a turbine torque which is a torque on the input shaft 3a as a torque on the rotating member on the input shaft 3a side, that is, a transmission input torque Ti. This turbine torque Tt is equivalent to the engine torque Te (= Tt / t) in consideration of the torque ratio t of the torque converter 2. To represents the transmission output torque which is the torque on the output shaft 3b as the torque on the rotating member on the output shaft 3b side. Tcapl is the torque capacity of a frictional engagement element that performs an engagement operation during gear shifting (hereinafter, referred to as engagement-side clutch torque). Tcdrn is a torque capacity (hereinafter, referred to as a release-side clutch torque) of a friction engagement element that performs a release operation at the time of shifting. a1, a2, b1, b2, c1, c2, d1, and d2 are constants when the equations (1) and (2) are derived, respectively. The inertia in each rotary element and the gear of the planetary gear device It is a coefficient determined by design from the ratio. The specific numerical value of this constant differs depending on, for example, the type of shift (for example, a combination of a shift pattern and a shift gear before and after the shift). Therefore, although the above equation of motion is one predetermined equation, the equation of motion corresponding to each type of shift, which is a constant different for each type of shift, is used for shifting of the automatic transmission 3.

  Equations (1) and (2) are the gear train motion equations of the automatic transmission 3 that formulate the relationship between the target shift characteristic and the control operation amount. The target shift characteristic can express each target value of the shift time and the driving force, and can be handled on a gear train equation of motion. In the present embodiment, the input shaft acceleration dωt / dt is used as an example of a physical quantity that can express the shift time. The transmission output torque To is used as an example of a physical quantity that can express the driving force. Here, in the present embodiment, the target shift characteristic is a target value (target gradient) of the input shaft acceleration dωt / dt. The target shift characteristic may be a target shift time value (target shift time) or the like.

  On the other hand, in the present embodiment, the control operation amount of the control (feedback control) for establishing the target shift characteristic is determined by the turbine torque Tt (the engine torque Te is also agreed), the engagement side clutch torque Tcapl, and the release side clutch torque Tcdrn. The three values are set. Then, while the equation of motion is composed of the two equations of Equations (1) and (2), there are three control manipulated variables, so that the control manipulated variables that satisfy the two target shift characteristics are uniquely solved. It is not possible. Note that the output shaft acceleration dωo / dt in each equation is calculated from the output shaft rotation speed ωo, which is a detection value of the output shaft rotation speed sensor 83.

  Therefore, in the present embodiment, the torque sharing ratio of the transmission torque that is assigned to the disengagement-side clutch and the engagement-side clutch is used as a constraint condition for obtaining the solutions of the equations of motion of Expressions (1) and (2). By setting the torque sharing ratio as a constraint, the transfer of torque between the disengagement side clutch and the engagement side clutch during shifting (that is, the degree of shift progress) can be incorporated into the equation of motion, and the control operation amount can be uniquely solved. be able to.

  The torque sharing ratio is, for example, the total transmission torque (total transmission torque) that the disengagement-side clutch and the engagement-side clutch need to cover during the shift of the automatic transmission 3, for example, the torque on the input shaft 3a (total transmission on the input shaft). This is the ratio of the transmission torque shared by the two friction engagement elements to the total transmission torque on the input shaft when the torque is replaced by the torque. Then, such a torque sharing ratio is changed according to the shift progress degree during the shift.

  In the present embodiment, the torque sharing ratio of the engagement-side clutch is set to “xapl”, the torque sharing ratio of the disengagement-side clutch is set to “xdrn”, and the respective torque sharing ratios reflect the transfer of torque during shifting. The following equation (3) and equation (4) are used to define the torque sharing rate x (for example, 0 ≦ x ≦ 1) that changes in a time series.

xapl = x (3)
xdrn = 1−x (4)
The relational expression between the engagement-side clutch torque Tcapl and the release-side clutch torque Tcdrn is based on “Tcapl” and “Tcdrn” replaced with the torque on the input shaft 3a, and Expressions (3) and (4). , "X" (= xapl) and "1-x" (= xdrn). Then, from the equations (1) and (2) and the relational expression between “Tcapl” and “Tcdrn”, the control operation amounts such as the turbine torque Tt, the engagement side clutch torque Tcapl, and the release side clutch torque A relational expression for calculating Tcdrn is derived. The turbine torque Tt (the engine torque Te also agrees) is a relational expression using “x” (= xapl), “1-x” (= xdrn), input shaft acceleration dωt / dt, transmission output torque To, and the like. Is represented by Similarly, the engagement side clutch torque Tcapl is represented by a relational expression using “x” (= xapl), input shaft acceleration dωt / dt, transmission output torque To, and the like. Similarly, the release-side clutch torque Tcdrn is expressed by a relational expression using “1-x” (= xdrn), input shaft acceleration dωt / dt, transmission output torque To, and the like.

  That is, in the shift model of the present embodiment, the equation of motion (Equations (1) and (2)) of the automatic transmission 3 including the target shift characteristics and the control operation amount, and the relationship (Equation (3)) representing the torque sharing ratio. , (4)) to calculate the control operation amount based on the target shift characteristic. As described above, in the present embodiment, the shift of the automatic transmission 3 is executed by using the shift model by adding the constraint condition set by the torque sharing ratio x to the equations (1) and (2). Therefore, even if there are three control operation amounts for two target shift characteristics, the three control operation amounts can be appropriately determined using the shift model. This shift model is one predetermined model, but as described above, a gear train motion equation having a different constant for each type of shift (for example, a combination of a shift pattern and a shift gear before and after a shift) is used. A shift model corresponding to each type of shift is used for shifting of the automatic transmission 3.

  Then, the ECU 5 calculates a target shift characteristic and a control operation amount according to the shift progress degree for each shift pattern. The shift pattern is, for example, a power-on upshift, a power-off upshift, a power-on downshift, and a power-off downshift.

  For example, in the case of a power-on upshift, when the hydraulic control for the friction engagement elements according to the target gear position is started, first, the share of the required torque capacity in each friction engagement element changes to a torque phase stage, and thereafter, Then, the shift is completed through an inertia phase stage in which the gear ratio of the automatic transmission 3 changes. That is, the shift of the automatic transmission 3 proceeds to a stage before the torque phase, a stage of the torque layer, a stage of the inertia phase, and a stage at the end of the shift.

  A suitable torque sharing ratio that changes in accordance with the progress of such a shift is obtained by previously creating a map or the like set in accordance with the shift progress degree for each shift pattern by experiment or simulation. It is remembered. The ECU 5 reads out the torque sharing ratio according to the shift progress degree during the shift control, applies the torque sharing ratio to the shift model together with the target shift characteristics, and executes the control operation amount (the required input torque of the input shaft 3a, the engagement The required torque capacity of the friction engagement elements on the side and the release side is calculated.

  Then, the ECU 5 controls the engagement side and the release side frictional engagement elements (oil pressure control) according to the shift progress degree so that the required torque capacity is achieved. In addition, the ECU 5 controls the shift so that the actual input shaft rotation speed ωi becomes the target input shaft rotation speed in accordance with the shift progress degree based on the target shift characteristics.

-Target shift characteristic update control-
Next, a description will be given of the target shift characteristic update control executed by the ECU 5.

  As described above, the ECU 5 forms the first to fourth gear stages based on the target shift characteristics including the target gradient (= input shaft acceleration dωt / dt) according to the shift progress of the input shaft rotation speed ωi. The shift is performed by controlling the hydraulic pressure of the clutches C1 to C4 and the first and second brakes B1 and B2. The "shift progress degree" is (input shaft rotational speed-pre-shift synchronous rotational speed) / (shift synchronous rotational speed-pre-shift synchronous rotational speed).

  Specifically, the ECU 5 is configured to update and set the target shift characteristic based on the vehicle state at the start of the shift. More specifically, when the target shift speed is set based on the shift map, the ECU 5 determines, for example, the transmission input torque Ti and the vehicle speed v (calculated from the output signal of the output shaft rotation speed sensor 83) at the start of the shift. Based on the shift characteristic map stored in the ROM 52, the target shift characteristic is updated and set. The shift characteristic map uses the transmission input torque Ti and the vehicle speed v indicating the vehicle state as parameters, and sets the target gradient and the target shift time of the input shaft rotation speed ωi required according to the transmission input torque Ti and the vehicle speed v. This is a map set in advance by an experiment, a simulation, or the like.

  Further, when performing a shift based on the updated target shift characteristic, the ECU 5 performs the shift from the upshift to the downshift or from the downshift to the upshift when a multiplex shift is performed. At the time of switching from downshifting or downshifting to upshifting, the target shift characteristic is updated and set based on the vehicle state. Specifically, when the target gear position is changed, the ECU 5 refers to the shift characteristic map based on the transmission input torque Ti and the vehicle speed v at the time of switching from upshift to downshift or from downshift to upshift. To update the target shift characteristics.

  In addition, the ECU 5 is configured to maintain the updated target shift characteristic in principle, except when shifting is started and when switching from upshift to downshift or from downshift to upshift.

  FIG. 7A is a diagram schematically illustrating an example of a target shift characteristic in a downshift. The target shift characteristic updated and set by the ECU 5 includes a target gradient of the input shaft rotation speed ωi according to the shift progress degree. In such a target shift characteristic, a relatively small target gradient # 1 is considered at the beginning of a shift (when the shift progress is small) in consideration of a hydraulic response delay, and a relatively small target gradient # 1 during a middle shift (when the shift progress is medium). A target slope # 2 that is relatively large is set at the end of the shift (when the degree of progress of the shift is large), and a relatively small target slope # 3 is set to suppress the blow-up.

  Then, the ECU 5 executes the shift after the update setting based on the target shift characteristics after the shift progress degree at the time of the update setting among the target shift characteristics set and updated.

FIG. 7B is a diagram schematically illustrating an example of a multiplex shift in which a downshift is switched after the middle of an upshift. In the following description, for convenience, there is no change in the vehicle speed v during the shift, and there is no change in the vehicle speed v during the shift, and the synchronization before the shift in the upshift is performed in the n-speed (n is a positive integer) → n + 1-speed upshift and the n + 1-speed → n-speed downshift It is assumed that the rotation speed ω _BU is the same as the post-shift synchronous rotation speed ω _{AD in} downshifting. Note that such an assumption is merely for convenience of description, and the present invention is not limited thereto, and the present invention can be applied to, for example, a jump speed change or a change in the vehicle speed v during the speed change.

As shown in FIG. 7B, at the start of the upshift, the target shift is such that it decreases from the pre-shift synchronous rotational speed ω _{BU with a} small target slope １U1, and then decreases with a large target slope △ U2 in the middle of shifting. The characteristic (see the broken line in FIG. 7B) is updated and set. After that, when the downshift is switched to the middle of a shift in an upshift or the like (for example, a shift progress degree of 0.5), the ECU 5 changes the target shift characteristic shown by the broken line in FIG. 7B to the one-dot chain line in FIG. Is updated to the target shift characteristic indicated by. Then, the ECU 5 sets the target shift characteristic (FIG. 7 (b)) after the shift progress degree (0.5) at the time of update setting, out of the updated target shift characteristic (dotted line in FIG. 7 (b)). The shift after the update setting is executed on the basis of the thick dashed line in FIG. Therefore, in the subsequent downshift, after the input shaft rotation speed ωi increases with a large target gradient △ D2 in the middle of the shift, the input shaft rotation speed ωi increases with the small target gradient △ D3 in the end of the shift, and becomes the post-shift synchronous rotation speed ωAD _. As described above, hydraulic control is performed.

  On the other hand, when multiple shifts are performed, such as switching to a downshift at the beginning of an upshift or switching to an upshift at the beginning of a downshift, the time required to complete the shift may be longer than necessary. is there. FIG. 7C is a diagram schematically illustrating an example of a multiple shift in which a downshift is switched at the beginning of an upshift.

  As shown in FIG. 7C, when the downshift is switched at the beginning of the upshift (for example, at a shift progress degree of 0.1), the ECU 5 changes the target shift characteristic shown by the broken line in FIG. c) Update and set to the target shift characteristic indicated by the one-dot chain line. Then, the ECU 5 sets the target shift characteristic (FIG. 7 (c)) after the shift progress degree (0.9) at the time of update setting, out of the updated target shift characteristic (dotted line in FIG. 7 (c)). The shift after the update setting is executed on the basis of the thick dashed line in FIG. For this reason, the shift after the update setting is started with the relatively small target slope ΔD3 toward the engagement completion.

  In addition, even when the mode is switched from the upshift to the downshift, the shift may progress in the upshift direction (the shift progress degree in the downshift decreases) due to a delay in the hydraulic response of the friction engagement element. Even if such a shift progression is reduced, when the downshift is switched at the beginning of the upshift, the input shaft rotational speed ωi is easily increased because only a small target gradient ΔD3 is buffered (stored). Otherwise, the time required to complete the shift may be longer than necessary.

  Therefore, in the present embodiment, not only is the target shift characteristic updated when the shift is started or when multiple shifts are performed, but also when the shift is greatly reversed, the actual input shaft rotation speed ωi is matched. The target shift characteristic is updated and set.

  Specifically, the ECU 5 is configured to update and set the target shift characteristic even when the shift progress degree has decreased by a predetermined value R or more after updating the target shift characteristic. Also in this case, the ECU 5 executes the shift after the update setting based on the target shift characteristics after the shift progress degree at the time of the update setting among the target shift characteristics that have been updated and set.

  In this way, if the shift progression decreases by the predetermined value R or more after the target shift characteristic is updated and set (for example, when the shift progression decreases to 0.5), the target shift characteristic is updated and set, and Since the downshift is performed based on the target shift characteristics after the shift progress degree (0.5) at the time of the update setting, a relatively large target gradient corresponding to the lowered input shaft rotation speed ωi (for example, FIG. △ D2) is buffered. Therefore, the input shaft rotation speed ωi reduced due to the hydraulic response delay can be increased with a relatively large target gradient, and the time required for the completion of the shift can be suppressed from becoming unnecessarily long.

  In addition, even when multiple shifts are performed a plurality of times in one shift, the ECU 5 updates the target shift characteristic when the shift progress degree decreases by a predetermined value R or more after updating the target shift characteristic. The time required for completion can be optimized.

-Flow chart and timing chart-
Next, an example of the target shift characteristic update control executed by the ECU 5 will be described with reference to a flowchart shown in FIG. 5 and a timing chart shown in FIG. The flowchart shown in FIG. 5 is repeated at predetermined time intervals.

<In the case of time t ₀ of Figure 6 (a)>
In step ST1 in the flowchart, the ECU 5 determines whether or not the shift control is being performed. At time t ₀ in FIG. 6 (a), because not yet shift is started, the determination becomes NO at step ST1, it is RETURN.

<In the case of time t ₁ of FIG. 6 (a)>
In step ST1, ECU 5 is, determines whether the shift control in so time t ₁ in FIG. 6 (a) of during the gear shift, the determination in step ST1 proceeds to YES, step ST2.

In the next step ST2, the ECU 5 determines whether or not to start shifting, or to switch from upshift to downshift, or to switch from downshift to upshift. For example, the ECU 5 determines that the point in time when the target gear position is set based on the shift map using the vehicle speed v and the accelerator opening as parameters is the start of gear shifting. Figure 6 time t ₁ of (a), so that at the shift start, the determination in step ST2 goes to YES, and step ST3.

  In the next step ST3, the ECU 5 updates and sets the target shift characteristic with reference to the shift characteristic map based on, for example, the transmission input torque Ti and the vehicle speed v at the start of the shift. Specifically, the target shift characteristic for upshifting is updated and set as indicated by the broken line in FIG. 6B, and the process proceeds to step ST4.

In the next step ST4, the ECU 5 starts the shift after the update setting based on the target shift characteristics after the shift progress degree at the time of the update setting. The time t ₁ in FIG. 6A is the start of the shift and the shift progress degree is 0.0. Therefore, the ECU 5 applies the target shift characteristic as indicated by the broken line in FIG. To start shifting, and then return. As a result, the target gradient △ U1 at the beginning of the upshift is buffered, and the ECU 5 starts hydraulic control of the friction engagement element using the above-described shift model based on the target gradient △ U1.

<In the case of time t ₂ of Fig. 6 (a)>
Time t ₂ in FIG. 6 (a), because during the shift control, the determination in step ST1 proceeds YES, to step ST2. In the next step ST2, the ECU 5 determines whether or not to start shifting, or to switch from upshift to downshift, or to switch from downshift to upshift, as shown in FIG. time t ₂ is the upshift early, because none of the time shift start time and multiple shift initiation, the determination in step ST2, the process proceeds nO, to step ST5.

In the next step ST5, the ECU 5 determines whether or not the shift progress degree has decreased by a predetermined value R or more after updating the target shift characteristic. At time t ₂ of FIG. 6 (a), based on the target slope △ U1, the input shaft rotational speed ωi are decreased gradually, since the shift is in progress as shown in FIG. 6 (b), the step ST5 Is NO, and the process proceeds to step ST6.

  In the next step ST6, the ECU 5 holds the target shift characteristic, and then performs RETURN. As a result, the target shift characteristic as indicated by the broken line in FIG. 6B maintained at the start of the shift is maintained, and the ECU 5 uses the above-described shift model based on the target gradient △ U1 to execute the friction engagement element. The hydraulic control of is continued.

<In the case of time t ₃ of FIG. 6 (a)>
Time t ₃ in FIG. 6 (a), because during the shift control, the determination in step ST1 proceeds YES, to step ST2. In the next step ST2, the ECU 5 determines whether or not to start shifting, or to switch from upshift to downshift, or to switch from downshift to upshift. Time t _{3 in} FIG. 6A is just the time of switching from upshift to downshift, so the determination in step ST2 is YES, and the process proceeds to step ST3.

  In the next step ST3, the ECU 5 updates and sets the target shift characteristic with reference to the shift characteristic map based on, for example, the transmission input torque Ti and the vehicle speed v at the time of switching. Specifically, target shift characteristics for downshifting are set as shown by the broken line in FIG. 6C, and the process proceeds to step ST4.

In the next step ST4, the ECU 5 starts the shift after the update setting based on the target shift characteristics after the shift progress degree at the time of the update setting. At time t ₃ in FIG. 6 (a), since the shift progress degree is 0.9 when seen as a downshift, ECU 5, of the target gear characteristics shown by the broken line in FIG. 6 (c), the time update setting The shift after the update setting is started based on the target shift characteristics after the shift progress degree of 0.9 (thick broken line in FIG. 6C), and then RETURN is performed. As a result, the relatively small target gradient △ D ₁₃ at the end of the downshift is buffered, and the ECU 5 starts the hydraulic control of the friction engagement element using the above-described shift model based on the target gradient △ D _13. I do.

<Case at time t _{4 in} FIG. 6A>
Time t ₄ in FIG. 6 (a), because during the shift control, the determination in step ST1 proceeds YES, to step ST2. The time t ₄ in FIG. 6 (a), since none of the time shift start time and multiple shift initiation, the determination in step ST2, the process proceeds NO, to step ST5.

In the next step ST5, the ECU 5 determines whether or not the shift progress degree has decreased by a predetermined value R or more after updating the target shift characteristic. 6 at time t ₄ of (a), but shifted by a hydraulic pressure response delay in the upshift direction of the frictional engagement elements is in progress, yet reduced shift progress degree is a predetermined value R (e.g., 0.4) or more Therefore, the determination in step ST5 is NO, and the process proceeds to step ST6. In the next step ST6, the ECU 5 holds the target shift characteristic shown by the thick broken line in FIG. 6C, and then performs RETURN.

<In the case of time t ₅ in Figure 6 (a)>
Time t ₅ in FIG. 6 (a), because during the shift control, the determination in step ST1 proceeds YES, to step ST2. The time t ₅ in FIG. 6 (a), since none of the time shift start time and multiple shift initiation, the determination in step ST2, the process proceeds NO, to step ST5.

In the next step ST5, the ECU 5 determines whether or not the shift progress degree has decreased by a predetermined value R or more after updating the target shift characteristic. At time t ₅ in FIG. 6 (a), the fact and that only a relatively small target slope △ D ₁ 3 not buffered for transmission to upshift direction is still in progress by the hydraulic response delay of the frictional engagement elements Together with the above, the shift progress degree has decreased by the predetermined value R (0.4) and has decreased to 0.5, so the determination in step ST5 is YES, and the process proceeds to step ST3.

  In the next step ST3, the ECU 5 updates and sets the target shift characteristic with reference to the shift characteristic map based on the transmission input torque Ti and the vehicle speed v when the shift progress decreases by the predetermined value R. Specifically, target shift characteristics for downshifting are set as shown by the broken line in FIG. 6D, and the process proceeds to step ST4.

In the next step ST4, the ECU 5 starts the shift after the update setting based on the target shift characteristics after the shift progress degree at the time of the update setting. At time t ₅ in FIG. 6 (a), since the shift progress degree is 0.5, ECU 5, of the target gear characteristics shown by the broken line in FIG. 6 (d), the shift progress degree 0 when updating settings. The shift after the update setting is started based on the target shift characteristics after 5 (the thick broken line in FIG. 6D), and then the return is performed. Thus, since a relatively large target slope △ D ₂ 2 shift the middle in the down-shift is buffered, ECU 5, using the above-described transmission model based on the target slope △ D ₂ 2, hydraulic control of the friction engagement elements To start.

<In the case of time t ₆ of Figure 6 (a)>
Time t ₆ in FIG. 6 (a), because during the shift control, the determination in step ST1 proceeds YES, to step ST2. The time t ₆ in FIG. 6 (a), since none of the time shift start time and multiple shift initiation, the determination in step ST2, the process proceeds NO, to step ST5.

In the next step ST5, the ECU 5 determines whether or not the shift progress degree has decreased by a predetermined value R or more after updating the target shift characteristic. At time t ₆ in FIG. 6 (a), the shifting by the hydraulic response delay to the upshift direction of the frictional engagement element to converge, since the shift is in progress as shown in FIG. 6 (d), in step ST5 Is NO, and the process proceeds to step ST6. In the next step ST6, the ECU 5 holds the target shift characteristic, and then performs RETURN. Thus, the input shaft rotational speed ωi is, after rising at a relatively large target slope △ D ₂ 2 in the transmission middle, the synchronized rotation speed omega _AD while rising at a relatively small target slope △ D ₂ 3 in the transmission late , The hydraulic control of the friction engagement element is performed.

  Note that, in relation to the claims, the processing of steps ST2 and ST3 executed by the ECU 5 is described in the claims as "at the start of a shift and at the time of switching from an upshift to a downshift or from a downshift to an upshift. Characteristic updating means for updating and setting the target shift characteristic on the basis of the characteristic shifting means. " Further, the processing of step ST6 corresponds to "characteristic holding means for holding updated target shift characteristics" in the claims. Further, the processing of step ST4 corresponds to "execution means for executing a shift after update setting based on target shift characteristics after the shift progress degree at the time of update setting among target shift characteristics set for update" in the claims. I do. Further, the processing in steps ST5 and ST3 is characterized in that the target shift characteristic is updated and set even when the shift progress degree has decreased by a predetermined value or more after the target shift characteristic is updated and set. Update means ”.

  As described above, according to the present embodiment, even when a multiple shift is performed after the start of a shift, the target shift characteristic is updated and set based on the vehicle state, so that the shift according to the shift mode after the switch is performed. Can be performed.

  Further, even when the shift progress decreases by a predetermined value R or more after the target shift characteristic is updated, the target shift characteristic is updated and based on the target shift characteristics after the shift progress at the time of the update setting. Since the downshift is executed, a relatively large target gradient corresponding to the reduced input shaft rotational speed ωi is buffered, so that the input shaft rotational speed ωi reduced due to the hydraulic response delay is reduced to a relatively large target gradient. Can be raised. This makes it possible to prevent the time required for completing the shift from becoming unnecessarily long, regardless of the stage at which the multiple shift is performed.

(Other embodiments)
The present invention is not limited to the embodiments, but can be embodied in various other forms without departing from its spirit or essential characteristics.

  In the above-described embodiment, the present invention is applied to the case of a multiple shift in which an upshift is switched to a downshift. However, the present invention is not limited to this, and may be applied to a case of a multiple shift in which a downshift is switched to an upshift. Good.

  Further, in the above embodiment, the case where the multiple shift is performed only once in one shift has been described. However, the present invention is not limited to this, and multiple multiple shifts may be performed in one shift. In addition, the time required until the shift is completed can be optimized.

  Further, in the above-described embodiment, the present invention is applied to the control of the automatic transmission 3 having the eight forward speeds. However, the present invention is not limited to this, and is applicable to the control of the automatic transmission having the seven forward speeds or less or the nine forward speeds or more. May be.

  Further, in the above embodiment, the present invention is applied to the FF vehicle 10, but is not limited thereto, and the present invention may be applied to an FR (front engine / rear drive) vehicle.

  Furthermore, in the above embodiment, the present invention is applied to the vehicle 10 equipped with the multi-cylinder gasoline engine 1, but the present invention is not limited to this, and the present invention may be applied to a vehicle equipped with a diesel engine or the like.

  As described above, the above-described embodiment is merely an example in all aspects, and should not be construed as limiting. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  According to the present invention, even when a multiplex shift that switches from an upshift to a downshift or a downshift to an upshift is performed after the target shift characteristic is updated, the time required for the completion of the shift is unnecessarily long. Since it can be suppressed, the present invention is extremely useful when applied to a control device for a stepped automatic transmission that performs a shift based on a target shift characteristic.

3 automatic transmission 5 ECU (control device)
B1 First brake (friction engagement element)
B2 Second brake (friction engagement element)
C1 First clutch (friction engagement element)
C2 2nd clutch (friction engagement element)
C3 3rd clutch (friction engagement element)
C4 4th clutch (friction engagement element)

Claims (1)

Control device for a stepped automatic transmission that executes a shift by controlling the hydraulic pressure of a plurality of frictional engagement elements forming a shift speed based on a target shift characteristic including a target gradient of a transmission input shaft rotation speed And
At the start of shifting, and at the time of switching from upshifting to downshifting or downshifting to upshifting, characteristic updating means for updating and setting the target shift characteristic based on the vehicle state;
Characteristic holding means for holding the target shift characteristic updated and set by the characteristic updating means,
Executing means for executing a shift after update setting, based on target shift characteristics after the shift progress degree at the time of update setting, among the target shift characteristics updated and set by the characteristic updating means,
The stepped automatic updating device is characterized in that the characteristic updating means is configured to update and set the target shift characteristic even when the shift progress degree decreases by a predetermined value or more after the update setting of the target shift characteristic. Transmission control device.

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