JP2007327525A - Shift control device for vehicular automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift control device for a vehicular automatic transmission, for suppressing the degradation of durability of an engaging side friction engaging element which actualizes coast-down shift even if shift stand-by control is executed during coast-down shift. <P>SOLUTION: A shift forcibly finishing means 110 forcibly finishes coast-down shift at the time when an elapsed time t<SB>e</SB>from starting the coast-down shift gets to a preset normal forcibly finishing time T<SB>B</SB>if shift stand-by control is not executed. On the other hand, it forcibly finishes the coast-down shift at the time when the elapsed time t<SB>e</SB>gets to a first shift stand-by control execution forcibly finishing time T<SB>1</SB>set longer than the normal forcibly finishing time T<SB>B</SB>if the shift stand-by control is executed. So, the degradation of durability of the engaging side friction engaging element which executes the coast-down shift is suppressed even if the shift stand-by control is executed during the coast-down shift. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shift control device for an automatic transmission for a vehicle that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements, and in particular, during coasting (coast). The present invention relates to a technique for limiting the lengthening of a shift time in a downshift.

  Automatic transmissions for vehicles that establish a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements are used in various vehicles. In such an automatic transmission, a technology is known that performs coast down shift when the vehicle decelerates and prepares for depression of the accelerator so that the vehicle can be accelerated with an appropriate driving force when accelerating again from when the vehicle decelerates. . Further, as in the automatic transmission control device described in Patent Document 1, when performing a coast down shift by re-engaging (clutch-to-clutch) between the disengagement side frictional engagement element and the engagement side frictional engagement element, In order to make the shift characteristics suitable, a technique for providing a shift line for coast down shift different from the shift line in the normal shift has been proposed.

JP 2003-269601 A

  However, in the conventional technique, when the brake operation is performed during the shift, it is difficult to engage the engagement side frictional engagement element at a predetermined synchronization timing due to the change in the deceleration caused by the brake. For example, the control accuracy may not be ensured.

  On the other hand, when it is determined that the driver intends to decelerate during the coast downshift, the shift standby control for stopping the increase of the engagement pressure of the engagement side frictional engagement element is executed, and the driver's If it is determined that there is no intention to decelerate, it is conceivable to achieve both acceleration response at the time of reacceleration and reduction of shift shock by canceling the shift standby control and proceeding with the shift.

  By the way, when the speed change period is prolonged, the durability of the friction engagement element is lowered. In order to solve this problem, a forced shift end control is performed to forcibly end the shift when the elapsed time from the start of the shift or the start of the inertia phase reaches a preset forced end time. However, when such forced shift end control is executed, interference between the shift standby control and the forced shift end control occurs. That is, although the shift standby control is executed and the shift is not allowed to proceed, the elapsed time is counted during that time, and when the elapsed time reaches the forced end time, The shift forced termination control is executed earlier than the point at which the shift is forcibly terminated in view of the durability of the elements, and the shift forced termination control is performed more than necessary. On the other hand, when the setting of the forced end time is lengthened, there is a problem that the durability of the friction engagement element is lowered when the shift standby control is not executed. In order to prevent control interference, it is conceivable to cancel the shift forced end control when the shift standby control is executed. In this case, however, the durability of the friction engagement element is increased when the shift period is prolonged. There was a problem of causing a drop.

  The present invention has been made against the background of the above circumstances. The purpose of the present invention is to execute a coast down shift by appropriately forcibly terminating the shift regardless of whether the shift standby control means is executed or not. An object of the present invention is to provide a shift control device for an automatic transmission for a vehicle in which a decrease in durability of an engaging frictional engagement element is suppressed.

  In order to solve such problems, the gist of the present invention is that (a) a vehicle automatic vehicle that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements. A transmission control device for an automatic transmission for a vehicle that performs a coast-down shift by re-engaging the disengagement side frictional engagement element and the engagement side frictional engagement element when the vehicle decelerates, wherein (b) the coast A decelerating intention determining means for determining whether or not the driver intends to decelerate during the downshift, and (c) when the determination of the decelerating intention determining means is affirmative, the engagement-side frictional engagement element is engaged. Shift standby means for executing shift standby control that stops the increase of the combined pressure and does not advance the shift, and (d) the deceleration intention determination means in a state where the increase of the engagement pressure is stopped by the shift standby means If the determination of Shift advancement means for canceling the speed standby control and increasing the engagement pressure of the engagement side frictional engagement element again to advance the shift, and (e) when the shift standby control is not executed by the shift standby means, The coast down shift is forcibly terminated when the elapsed time from the start of the coast down shift or the start of the inertia phase has reached a preset normal time forced end time, while the shift standby control is executed by the shift standby means. In this case, there is included a shift forced end means for forcibly terminating the coast down shift when the elapsed time reaches the forced end time set longer than the normal time forced end time.

  In this way, the decelerating intention determining means for determining whether or not the driver intends to decelerate during the coast downshift, and the engagement side friction when the determination of the decelerating intention determining means is affirmed. The shift standby means for stopping the increase of the engagement pressure of the engagement element so as not to proceed with the shift, and in the state where the increase of the engagement pressure is stopped by the shift standby means, the deceleration intention determination means In the case where the determination is negative, it has shift advancement means for increasing the engagement pressure of the engagement side frictional engagement element again to advance the shift. By preventing the coast down shift from proceeding when it is considered that the vehicle is intended to shift from the stop state to the stop state, it is possible to prevent the occurrence of a shift shock due to an unnecessary coast down shift. In addition, when it is no longer deceleration intention of the driver by advancing the coast downshift, it can be accelerated well response when accelerating again during deceleration. That is, it is possible to reduce the shift shock while making it possible to accelerate with good response when accelerating again from the time of deceleration of the vehicle.

  In addition, when the shift standby control by the shift standby means is not executed by the shift forced end means, the elapsed time from the start of the shift down or the inertia phase of the coast down shift has reached a preset normal time forced end time. Since the coast-down shift is forcibly terminated at the time, when the shift standby control is not performed, a longer time than necessary for the coast-down shift is prevented as much as possible, and the durability of the engagement side frictional engagement element is assured. When the shift standby control is executed by the shift standby means by the shift forced end means, the elapsed time is set longer than the normal time forced end time. Since the coast down shift is forcibly terminated when the forced end time is reached, even if the shift standby control is executed during the coast down shift, Deterioration of the durability of the engagement side frictional engagement element to perform coast downshift is suppressed.

  Preferably, the forced shift end means forcibly ends the coast down shift when a predetermined time has elapsed from the end of the shift standby control when the shift standby control is executed by the shift standby means. It is something to be made. In this way, when the shift standby control is performed, it is possible to prevent the coast down shift from being prolonged more than necessary, and to reduce the durability of the engagement side frictional engagement element as much as possible. Is prevented. Preferably, the predetermined time is easily set if the predetermined time is the same as the normal time forced end time.

  Preferably, the shift forcible end means is configured such that the elapsed time reaches a point at which a predetermined time has elapsed from the end of the shift standby control and a preset forced end time at the time of execution of the shift standby control. The coast down shift is forcibly terminated when one of them occurs earlier. In this way, prolonged coast down shifting can be reliably prevented, and a decrease in durability of the engagement side frictional engagement element can be suitably prevented.

  Preferably, the frictional engagement element is a hydraulic frictional engagement device, and the shift standby unit is configured so that when the determination of the intention to decelerate the determination is affirmed, The shift of the engagement side hydraulic pressure supplied to the engagement device is stopped so as not to proceed with the shift, and the shift progress means is configured to perform the engagement when the determination of the deceleration intention determination means is negative. The engagement-side hydraulic pressure supplied to the combined-side hydraulic friction engagement device is increased again to advance the shift. In this way, in a practical vehicle automatic transmission equipped with a plurality of hydraulic friction engagement devices, it is possible to reduce the shift shock while enabling acceleration with good response when accelerating again from the time of deceleration of the vehicle. Can do.

  Preferably, the decelerating intention determination means determines whether the brake operation is released, the accelerator operation is performed, or the release speed of the brake operation amount is equal to or higher than a predetermined value. It is determined that the driver has no intention of deceleration. In this way, it is possible to suitably determine whether or not the driver intends to decelerate.

  Preferably, the vehicle further includes a turning determination unit that determines whether or not the vehicle is in a turning state, and the shift standby unit has the engagement side on condition that the determination of the turning determination unit is denied. The increase in the engagement pressure of the friction engagement element is stopped to prevent the shift from proceeding. In this way, when the vehicle is turning, there is a high possibility that the vehicle will be accelerated again immediately after the brake operation is performed for turning. It can suppress suitably.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating the configuration of an automatic transmission for a vehicle (hereinafter referred to as an automatic transmission) 10 to which the present invention is preferably applied. FIG. It is an action | operation table | surface explaining the action | operation of the friction engagement element at the time of establishing a step. This automatic transmission 10 includes a first transmission unit mainly composed of a double pinion type first planetary gear unit 12 in a transmission case (hereinafter referred to as a case) 26 as a non-rotating member attached to a vehicle body. 14 and a second transmission unit 20 mainly composed of a single pinion type second planetary gear unit 16 and a double pinion type third planetary gear unit 18 on a common axis, and an input shaft 22 Are rotated and output from the output shaft 24. The input shaft 22 corresponds to an input rotating member, and in this embodiment is the turbine shaft of the torque converter 32 that is rotationally driven by the engine 30 that is a power source for traveling. The output shaft 24 corresponds to an output rotating member, and rotationally drives the left and right drive wheels sequentially through, for example, a differential gear device (final reduction gear) (not shown) and a pair of axles. The automatic transmission 10 is configured substantially symmetrically with respect to its axis, and the lower half of the axis is omitted in the skeleton diagram of FIG.

  The first planetary gear unit 12 includes a sun gear S1, a plurality of pairs of pinion gears P1 that mesh with each other, a carrier CA1 that supports the pinion gears P1 so as to rotate and revolve, and a ring gear R1 that meshes with the sun gear S1 via the pinion gears P1. The carrier CA1 and the ring gear R1 constitute three rotating elements. The carrier CA1 is connected to the input shaft 22 and driven to rotate, and the sun gear S1 is fixed to the case 26 so as not to rotate. The ring gear R <b> 1 functions as an intermediate output member, is rotated at a reduced speed with respect to the input shaft 22, and transmits the rotation to the second transmission unit 20. In the present embodiment, the path for transmitting the rotation of the input shaft 22 to the second transmission unit 20 at the same speed is the first intermediate output path for transmitting the rotation at a predetermined constant gear ratio (= 1.0). The first intermediate output path PA1 includes a direct connection path PA1a that transmits rotation from the input shaft 22 to the second transmission unit 20 without passing through the first planetary gear unit 12, and a first planet from the input shaft 22. There is an indirect path PA1b that transmits the rotation to the second transmission unit 20 via the carrier CA1 of the gear device 12. Further, the transmission ratio from the input shaft 22 to the second transmission unit 20 via the carrier CA1, the pinion gear P1 disposed on the carrier CA1, and the ring gear R1 is larger than the first intermediate output path PA1 (> 1). .0) is a second intermediate output path PA2 that transmits the rotation of the input shaft 22 with a reduced speed (deceleration).

  The second planetary gear device 16 includes a sun gear S2, a pinion gear P2, a carrier CA2 that supports the pinion gear P2 so as to rotate and revolve, and a ring gear R2 that meshes with the sun gear S2 via the pinion gear P2. The third planetary gear unit 18 includes a sun gear S3, a plurality of pairs of pinion gears P2 and P3 that mesh with each other, a carrier CA3 that supports the pinion gears P2 and P3 so as to rotate and revolve, and a sun gear S3 via the pinion gears P2 and P3. A meshing ring gear R3 is provided.

  In the second planetary gear device 16 and the third planetary gear device 18, four rotating elements RM <b> 1 to RM <b> 4 are configured by being partially connected to each other. Specifically, the first rotating element RM1 is configured by the sun gear S2 of the second planetary gear unit 16, and the carrier CA2 of the second planetary gear unit 16 and the carrier CA3 of the third planetary gear unit 16 are integrally connected to each other. The second rotating element RM2 is configured, and the ring gear R2 of the second planetary gear unit 16 and the ring gear R3 of the third planetary gear unit 18 are integrally connected to each other to configure the third rotating element RM3, and the third planetary gear unit. The 18th sun gear S3 constitutes a fourth rotating element RM4. In the second planetary gear device 16 and the third planetary gear device 18, the carriers CA2 and CA3 are configured by a common member, the ring gears R2 and R3 are configured by a common member, and the second planetary gear device 18 The pinion gear P <b> 2 of the planetary gear device 16 is a Ravigneaux type planetary gear train that also serves as the second pinion gear of the third planetary gear device 18.

  The automatic transmission 10 includes a clutch C1, a clutch C2, a clutch C3, and a clutch C4 as friction engagement elements for establishing a plurality of gear stages having different gear ratios (hereinafter simply referred to as a clutch C unless otherwise distinguished). , A brake B1 and a brake B2 (hereinafter, simply referred to as a brake B unless otherwise distinguished), the first rotating element RM1 (sun gear S2) is selectively provided to the case 26 via the first brake B1. The rotation is stopped by being connected to the ring gear R1 (that is, the second intermediate output path PA2) of the first planetary gear device 12, which is an intermediate output member, via the third clutch C3, and the fourth clutch C4 is further connected. To the carrier CA1 of the first planetary gear unit 12 (that is, the indirect path PA1b of the first intermediate output path PA1). . The second rotation element RM2 (carriers CA2 and CA3) is selectively coupled to the case 26 via the second brake B2 and stopped rotating, and the input shaft 22 (ie, the first intermediate) via the second clutch C2. It is selectively connected to the direct connection path PA1a) of the output path PA1. The third rotation element RM3 (ring gears R2 and R3) is integrally connected to the output shaft 24 to output rotation. The fourth rotation element RM4 (sun gear S3) is selectively coupled to the ring gear R1 via the first clutch C1. Between the second rotating element RM2 and the case 26, a one-way clutch F1 that allows forward rotation of the second rotating element RM2 (the same rotation direction as the input shaft 22) and prevents reverse rotation is provided in the second brake. It is provided in parallel with B2.

  The operation table of FIG. 2 is a table for explaining the operation states of the clutches C1 to C4 and the brakes B1 and B2 when each shift stage (gear stage) is established in the automatic transmission 10, and “◯” indicates engagement. The state, “(◯)” represents the engaged state only during engine braking, and the blank represents the released state. Since the one-way clutch F1 is provided in parallel to the brake B2 that establishes the first shift stage “1st”, it is not always necessary to engage the brake B2 when starting (acceleration). Further, the gear ratio of each gear stage is appropriately determined by the gear ratios ρ1, ρ2, and ρ3 of the first planetary gear device 12, the second planetary gear device 16, and the third planetary gear device 18.

  FIG. 3 is a collinear diagram in which the rotational speeds of the rotating elements of the first transmission unit 14 and the second transmission unit 20 can be represented by straight lines, and the lower horizontal line indicates the rotational speed “0”. The horizontal line indicates the rotational speed “1.0”, that is, the same rotational speed as the input shaft 22. Further, each vertical line of the first transmission unit 14 represents the sun gear S1, the ring gear R1, and the carrier CA1 in order from the left side, and the interval therebetween is the gear ratio ρ1 (= sun gear S1 of the first planetary gear unit 12). The number of teeth / the number of teeth of the ring gear R1). The four vertical lines of the second transmission unit 20 indicate the first rotation element RM1 (sun gear S2), the second rotation element RM2 (carrier CA2 and carrier CA3), and the third rotation element RM3 (in order from the left side to the right end. The ring gear R2 and the ring gear R3), the fourth rotating element RM4 (sun gear S3), and the distance between them depends on the gear ratio ρ2 of the second planetary gear device 16 and the gear ratio ρ3 of the third planetary gear device 18. Determined.

  As shown in FIGS. 2 and 3, the first clutch C <b> 1 and the second brake B <b> 2 are engaged, and the fourth rotating element RM <b> 4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14. At the same time, when the rotation of the second rotation element RM2 is stopped, the third rotation element RM3 coupled to the output shaft 24 is rotated at the rotation speed indicated by “1st”, and the largest gear ratio (= the rotation of the input shaft 22). The first shift stage “1st” of speed / rotation speed of the output shaft 24 is established. Further, the first clutch C1 and the first brake B1 are engaged, and the fourth rotation element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotation element RM1 is When the rotation is stopped, the third rotation element RM3 is rotated at the rotation speed indicated by “2nd”, and the second speed “2nd” having a speed ratio smaller than that of the first speed “1st” is established. Further, the first clutch C1 and the third clutch C3 are engaged, and the fourth rotation element RM4 and the first rotation element RM1 are decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotation element RM1 is rotated. When the second transmission unit 20 is integrally rotated, the third rotation element RM3 is rotated at the rotation speed indicated by “3rd”, and the third shift stage “3rd” having a smaller gear ratio than the second shift stage “2nd” is generated. It is established. Further, the first clutch C1 and the fourth clutch C4 are engaged, the fourth rotating element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the first rotating element RM1 is When the input shaft 22 is rotated integrally with the input shaft 22, the third rotation element RM3 is rotated at the rotation speed indicated by "4th", and the fourth shift stage "4th" having a smaller gear ratio than the third shift stage "3rd" is established. Be made. Further, the first clutch C1 and the second clutch C2 are engaged, and the fourth rotating element RM4 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the second rotating element RM2 is input. When the shaft 22 is rotated together with the shaft 22, the third rotation element RM3 is rotated at a rotational speed indicated by "5th", and the fifth shift stage "5th" having a lower speed ratio than the fourth shift stage "4th" is established. It is done. Further, when the second clutch C2 and the fourth clutch C4 are engaged and the second transmission unit 20 is rotated integrally with the input shaft 22, the third rotational element RM3 has a rotational speed indicated by “6th”, that is, the input shaft. Thus, the sixth shift stage “6th” having a smaller gear ratio than the fifth shift stage “5th” is established. The gear ratio of the sixth gear stage “6th” is 1. Further, the second clutch C2 and the third clutch C3 are engaged, the first rotating element RM1 is decelerated and rotated with respect to the input shaft 22 via the first transmission unit 14, and the second rotating element RM2 is When rotated integrally with the input shaft 22, the third rotation element RM3 is rotated at the rotational speed indicated by "7th", and the seventh shift stage "7th" having a smaller gear ratio than the sixth shift stage "6th" is established. Be made. Further, when the second clutch C2 and the first brake B1 are engaged, the second rotating element RM2 is rotated integrally with the input shaft 22, and when the first rotating element RM1 is stopped from rotating, the third rotating element RM3 is rotated at the rotational speed indicated by “8th”, and the eighth shift stage “8th” having a smaller gear ratio than the seventh shift stage “7th” is established. Further, when the third clutch C3 and the second brake B2 are engaged, the first rotating element RM1 is decelerated and rotated through the first transmission unit 14, and the second rotating element RM2 is stopped from rotating. The third rotation element RM3 is reversely rotated at the rotation speed indicated by “Rev1”, and the first reverse shift stage “Rev1” having the largest speed ratio in the reverse rotation direction is established. When the fourth clutch C4 and the second brake B2 are engaged, the first rotating element RM1 is rotated integrally with the input shaft 22, and the second rotating element RM2 is stopped from rotating, and the third rotating element RM3. Is reversely rotated at the rotational speed indicated by “Rev2”, and the second reverse shift stage “Rev2” having a smaller gear ratio than the first reverse shift stage “Rev1” is established. The first reverse speed “Rev1” and the second reverse speed “Rev2” correspond to the first speed and the second speed in the reverse rotation direction, respectively.

  As described above, the automatic transmission 10 of this embodiment establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements, that is, the clutches C1 to C4 and the brakes B1 and B2. 4 clutches C1 to C4 and two clutches C1 to C4 and two clutches C1 to C4 and two clutches C1 to C4 and two clutches 16 and 18, respectively. Since the forward shift 8-speed gear stage is achieved by switching the engagement of the brakes B1 and B2 by releasing the predetermined release-side frictional engagement element and engaging the engagement-side frictional engagement device, the brake B1 and B2 are small in size. The mounting property on the vehicle is improved. Further, as is apparent from the operation table of FIG. 2, it is possible to perform shifts at each gear stage by a so-called clutch-to-clutch that holds either one of the clutches C1 to C4 and the brakes B1 and B2. The clutches C1 to C4 and the brakes B1 and B2 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic frictions controlled by a hydraulic actuator such as a multi-plate clutch or brake. It is an engagement device.

  FIG. 4 is a block diagram for explaining a main part of a control system provided in the vehicle for controlling the automatic transmission 10 and the like of FIG. The electronic control unit 90 shown in FIG. 4 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and is stored in advance in the ROM using the temporary storage function of the RAM. By performing signal processing according to a program, output control of the engine 30, shift control of the automatic transmission 10, and the like are executed, and are configured separately for engine control, shift control, etc. as necessary. The

In FIG. 4, the operation amount Acc of the accelerator pedal 50 is detected by the accelerator operation amount sensor 52, and a signal representing the accelerator operation amount Acc is supplied to the electronic control unit 90. The accelerator pedal 50 is largely depressed according to the driver's required output amount, and thus corresponds to an accelerator operation member, and the accelerator operation amount Acc corresponds to an output request amount. In addition, a signal indicating the depression amount θ _SC of the operation of the brake pedal 54 of the foot brake which is a service brake is supplied to the electronic control unit 90. The brake pedal 54 corresponds to the brake operating member from being intended to be largely depressed in response to the deceleration demand of the driver, the amount of depression theta _SC corresponds to the brake operation amount.

Further, inhalation for detecting the temperature T _air of the intake air quantity sensor 60, the intake air for detecting an intake air quantity Q of the engine rotational speed sensor 58, the engine 30 for detecting the rotational speed N _E of the engine 30 The air temperature sensor 62, the throttle valve opening sensor 64 with an idle switch for detecting the fully closed state (idle state) of the electronic throttle valve of the engine 30 and the opening _θTH , the vehicle speed V (the rotational speed N of the output shaft 24). a brake sensor for the cooling water temperature sensor 68 for detecting a vehicle speed sensor 66, cooling water temperature T _W of the engine 30 for detecting the corresponding) to the _OUT, or whether the operation of the brake pedal 54 for detecting a depression amount theta _SC 70, the lever position sensor 74 for detecting a lever position (operating _{position) P SH} of the shift lever 72, ter AT for detecting emissions rotational speed _N T turbine speed sensor 76 for detecting (= rotational speed _{N IN} of the input shaft 22), which is the temperature of the hydraulic oil in the hydraulic control circuit 98 AT oil temperature _{T OIL} An oil temperature sensor 78, an acceleration sensor 80 for detecting the acceleration (deceleration) G of the vehicle, and the like are provided. From these sensors and switches, the engine speed N _E , the intake air amount Q, the intake air temperature are provided. T _air , throttle valve opening θ _TH , vehicle speed V, engine coolant temperature T _W , presence / absence of brake operation or stepping amount θ _SC , lever position P _SH of shift lever 72, turbine rotation speed N _T , AT oil temperature T _OIL A signal representing the acceleration (deceleration) G of the vehicle is supplied to the electronic control unit 90.

The shift lever 72 is disposed near the driver's seat, for example, and is manually operated to five lever positions “P”, “R”, “N”, “D”, or “S” as shown in FIG. It has become so. The “P” position is a parking position for releasing the power transmission path in the automatic transmission 10 and mechanically preventing (locking) the rotation of the output shaft 24 by the mechanical parking mechanism. The “R” position is an automatic transmission. The reverse travel position for reversing the rotation direction of the output shaft 24 of the machine 10, and the “N” position is a power transmission cutoff position for releasing the power transmission path in the automatic transmission 10. ”Position is a forward travel position in which automatic shift control is executed in a shift range (D range) that allows the first to eighth shifts of the automatic transmission 10, and the“ S ”position is a high speed side that can be shifted. This is a forward travel position where manual shift can be performed by switching between a plurality of shift ranges with different shift stages or a plurality of different shift stages. In this “S” position, the shift range or shift stage is shifted to the up side every time the shift lever 72 is operated, and the shift range or shift stage is shifted to the down side every time the shift lever 72 is operated. A “-” position is provided for this purpose. The lever position sensor 74 detects at which lever position (operation position) P _{SH the} shift lever 72 is located.

The hydraulic control circuit 98 includes a manual valve connected to the shift lever 72 via a cable, a link, or the like, for example, and the manual valve is mechanically operated as the shift lever 72 is operated. As a result, the hydraulic circuit in the hydraulic control circuit 98 is switched. For example, "D" position and the "S" forward circuit is output forward pressure P _D at position is mechanically established, the first gear position is the forward gear position "1st" to eighth speed "8th It is possible to travel forward while shifting. When the shift lever 72 is operated to the “D” position, the electronic control unit 90 determines that from the signal of the lever position sensor 74 and establishes the automatic shift mode, and sets the first shift stage “1st” to the first shift stage. Shift control is performed using all the forward shift speeds of 8 shift speeds “8th”.

The electronic control unit 90 shifts based on the actual vehicle speed V and the accelerator operation amount Acc from the relationship (map, shift diagram) stored in advance using the vehicle speed V and the accelerator operation amount Acc as parameters as shown in FIG. 6, for example. A shift control means 100 (see FIG. 8) that performs determination and performs shift control so as to obtain the determined shift speed is functionally provided. For example, the vehicle speed V decreases or the accelerator operation amount Acc increases. As a result, a low-speed gear stage having a large gear ratio is established. In this shift control, excitation, de-excitation, and current control of the linear solenoid valves SL1 to SL6 in the shift hydraulic control circuit 98 are executed so that the determined shift stage is established, and the clutch C and brake are controlled. The engagement / release state of B is switched and the transient hydraulic pressure in the shifting process is controlled. That is, by controlling the excitation and non-excitation of the linear solenoid valves SL1 to SL6, the clutch C and the brake B are engaged and disengaged, so that the first shift stage “1st” to the eighth shift stage “8th” are switched. One of the forward shift speeds is established. It should be _noted that various modes are possible, such as performing shift control based on the throttle valve opening θ _TH , the intake air amount Q, the road surface gradient, and the like.

In the shift diagram of FIG. 6, the solid line is a shift line for determining an upshift (upshift line), and the broken line is a shift line for determining a downshift (downshift line). Further, the shift line in the shift diagram of FIG. 6 indicates whether or not the actual vehicle speed V has crossed the line on the horizontal line indicating the actual accelerator operation amount Acc (%), that is, the value on which the shift on the shift line is to be executed ( is for determining whether exceeds the shift point vehicle speed) V _S, also will have been previously stored as a series of the values V _S that shift point vehicle speed. 6 illustrates the shift lines in the first to sixth shift stages among the first to eighth shift stages in which the automatic transmission 10 performs a shift.

  FIG. 7 is a circuit diagram showing a portion related to the linear solenoid valves SL1 to SL6 in the hydraulic control circuit 98, and the hydraulic actuators (hydraulic cylinders) 34, 36, 38, 40 of the clutches C1 to C4 and the brakes B1 and B2. The line hydraulic pressure PL output from the hydraulic pressure supply device 46 is regulated and supplied to the linear pressure valves SL1 to SL6, respectively. The hydraulic pressure supply device 46 includes a mechanical oil pump 48 (see FIG. 1) that is rotationally driven by the engine 30, a regulator valve that regulates the line hydraulic pressure PL, and the like. Is to control. The linear solenoid valves SL1 to SL6 have basically the same configuration, and are excited and de-energized independently by the electronic control unit 90 (see FIG. 4), and the hydraulic pressures of the hydraulic actuators 34 to 44 are independently regulated. It has come to be. In the shift control of the automatic transmission 10, for example, a so-called clutch-to-clutch shift is performed in which the release and engagement of the clutch C and the brake B involved in the shift are controlled simultaneously. For example, as shown in the engagement operation table of FIG. 2, in the downshift from the fifth speed to the fourth speed, the clutch C2 is disengaged and the clutch C4 is engaged, so that the release transient hydraulic pressure of the clutch C2 is suppressed so as to suppress the shift shock. And the engagement transient hydraulic pressure of the clutch C4 are appropriately controlled.

FIG. 8 is a functional block diagram illustrating a main part of the control function of the electronic control unit 90, that is, a control operation at the time of downshift during coasting accompanying an accelerator-off operation (hereinafter referred to as a coast downshift control operation). is there. In FIG. 8, the shift control means 100 executes shift determination based on the actual vehicle speed V and the accelerator operation amount Acc from a shift map stored in advance as shown in FIG. 6, for example, and executes the determined shift. For this purpose, the gear stage of the automatic transmission 10 is automatically switched by performing the shift output for the hydraulic control circuit 98. For example, when coasting when the automatic transmission 10 is at the third speed, the shift control means 100 performs a third speed → second speed downshift when the actual vehicle speed V is zero and the accelerator operation amount Acc is zero. When it is determined that the shift point vehicle speed V _3-2 to be executed is exceeded, the clutch C3 is started to be released, and the engagement pressure of the brake B1 is shown, for example, in FIG. to initiate the engagement of the brake B1 by raising so caused the engagement torque, while shifts from the speed ratio gamma ₃ of the third gear position in this state to the gear ratio gamma ₂ of the second shift stage Then, a command to complete the release of the clutch C3 and the engagement of the brake B1 is output to the hydraulic control circuit 98.

The deceleration intention determination means 102 determines whether or not there is a driver's intention to decelerate during the shift control by the shift control means 100. This determination is repeatedly executed at a predetermined time period during the coast down shift. For example, when it is determined based on a signal from the brake sensor 70 that the brake operation has been performed, the driver intends to decelerate. Judgment is made. Preferably, it is determined whether (a) the brake operation is released, (b) the accelerator operation is performed, or (c) the release speed of the brake operation amount is equal to or higher than a predetermined value. Is determined that the driver has no intention of deceleration. The determination of (a) is made based on on / off of the brake contact signal of the foot brake detected via the brake sensor 70, the brake master cylinder pressure (not shown), etc., and the brake contact signal is turned off. Alternatively, when the brake master cylinder pressure becomes a predetermined value or less, it is determined that the brake operation is released. The determination of (b) is made based on the operation amount Acc of the accelerator pedal 50 detected via the accelerator operation amount sensor 52, and when the accelerator operation amount Acc is not zero, that is, the engine 30 is in an idle state. If not, it is determined that the accelerator operation has been performed. The determination is based on the change rate of the depression amount theta _SC of the foot brake, which is detected via the brake sensor 70 (per predetermined time variation) and not shown brake master cylinder pressure change rate, etc. (c) performed Te, release speed of the brake operation amount is greater than or equal to a predetermined value when the rate of change of case or the brake master cylinder pressure change rate of the brake depression amount theta _SC is reduced below a predetermined value is equal to or less than a predetermined value It is determined. Note that only one of the above determinations (a), (b), and (c) may be performed, and it may be determined that the driver has no intention to decelerate based on the determination.

  The shift control means 100 includes a shift standby means 104, a shift progress means 106, and a shift forced end means 110. The shift standby means 104 determines whether the engagement side frictional engagement element of the engagement side frictional engagement element is determined when the determination of the deceleration intention determination means 102 is affirmed during coast downshift, that is, when it is determined that the driver intends to decelerate. Shift standby control is performed in which the increase in the engagement pressure is stopped to prevent the shift from proceeding. Here, the engagement side frictional engagement element is a hydraulic frictional engagement device on the side (newly engaged) engaged with the clutch-to-clutch shift in each coast downshift shift. In the automatic transmission 10 of the present invention, the clutch C3 is in the 8th gear → 7th gear downshift, the clutch C4 is in the 7th gear → 6th gear downshift, the clutch C1 is in the 6th gear → 5th gear downshift, and the clutch C1 is in the 5th gear → 4th gear downshift. When the clutch C4 is 4th speed → 3rd speed downshift, the clutch C3 corresponds to the brake B1 when the 3rd speed → 2nd speed downshift, and the brake B2 corresponds to the 2nd speed → 1st speed downshift. That is, in this embodiment, the shift standby unit 104 is supplied to the engagement-side hydraulic friction engagement device via the hydraulic control circuit 98 when the determination of the deceleration intention determination unit 102 is affirmed. The increase of the engagement side hydraulic pressure is stopped to prevent the shift from proceeding. In this embodiment, since the one-way clutch F1 attached to the brake B2 works in the second speed → first speed downshift, the engagement pressure is not controlled.

  Further, the shift progression means 106 is operated when the determination of the deceleration intention determination means 102 is negative in the case where the increase of the engagement pressure is stopped by the shift standby means 104 during the coast downshift, that is, the driving. When it is determined that the user does not intend to decelerate, the engagement pressure of the engagement side frictional engagement element that has been raised and stopped by the shift standby control by the shift standby unit 104 is increased again to advance the shift. . That is, when the determination by the deceleration intention determination means 102 is negative, the engagement-side hydraulic pressure supplied to the engagement-side hydraulic friction engagement device via the hydraulic control circuit 98 is increased again to change the speed. Proceed and continue execution of the well-known coast downshift.

  8 determines whether the vehicle is turning (during turning). Preferably, the vehicle is in a turning state based on whether or not a steering wheel or a steering angle of a wheel, lateral acceleration (lateral G), corner R, etc. detected by a sensor (not shown) exceeds a predetermined judgment reference value. It is determined whether or not there is. Preferably, the vehicle turning is determined when the accelerator return speed excluding the tip-in operation is greater than or equal to a predetermined value during acceleration orientation, or when the deceleration during braking is greater than or equal to a predetermined value. As a result, it is determined whether the vehicle is traveling before cornering or traveling during cornering without providing a detection device such as a rudder angle sensor. The turning determination means 108 may simply determine whether or not the vehicle is in a turning state, but determines whether or not the turning amount of the vehicle is within a predetermined range. Various aspects are possible.

  Here, the shift waiting means 104 is provided on the condition that the determination of the turning determination means 108 is negative, that is, the vehicle is not in a turning state, in addition to the driver's intention to decelerate. The above-mentioned shift standby control is performed so as to prevent the shift from proceeding by stopping the increase of the engagement-side hydraulic pressure supplied to the hydraulic friction engagement device. That is, when the determination of the turning determination means 108 is affirmative, that is, when the vehicle is in a turning state, the shift progression means 106 is engaged with the engagement side supplied to the engagement side hydraulic friction engagement device. Increase the hydraulic pressure to advance the shift.

  FIG. 9 is a time chart illustrating a hydraulic pressure command value corresponding to the hydraulic friction engagement device on the engagement side, that is, the brake B1, in the third speed → second speed coast downshift as an example of the coast downshift control operation of the present embodiment. FIG. 9 shows an example in which the driver does not intend to decelerate during the shift and the vehicle is reaccelerated. The hydraulic pressure command value shown in FIG. 9 is a command value for controlling the engagement state of the brake B1 via a linear solenoid valve SL5 provided in the hydraulic pressure control circuit 98. It corresponds.

  In the time chart shown in FIG. 9, first, at time t1, the shift control means 100 determines the start of the 3rd speed → 2nd speed downshift (shift output), and the supply of hydraulic oil to the brake B1 is started. The so-called first fill control is executed, the flow rate of the hydraulic oil output from the output port of the linear solenoid valve SL5 is temporarily increased rapidly, and then the engagement pressure is increased at a relatively slow predetermined speed. Oil is supplied to the brake B1. Next, when the operation of the foot brake is detected by the brake sensor 70 at time t2, and the determination of the deceleration intention determination means 102 is affirmed, that is, when it is determined that the driver intends to decelerate, the linear solenoid The increase of the engagement side hydraulic pressure that is being raised at a predetermined speed by the hydraulic oil supplied to the brake B1 via the valve SL5 is stopped and maintained constant, so that the gear shift does not proceed any further. Controlled. Next, when the release of the foot brake is detected by the brake sensor 70 at time t3 ′ and the determination of the intention to decelerate determination unit 102 is negative, that is, when it is determined that the driver does not intend to decelerate, the linear The increase of the engagement side hydraulic pressure supplied to the brake B1 via the solenoid valve SL5 is started again. At time t4, the brake B1 is completely engaged, and the third-speed → second-speed downshift is completed. Similar to the control shown in FIG. 9 described above, such control is performed not only when the driver performs a brake operation after the shift output is started, but also when the driver performs the brake operation from the third speed to the second speed. Even when the downshift is performed before time t1 is determined, the same process is executed.

  As shown in FIG. 9, in the control of this embodiment, the shift standby control is performed in a state where the determination of the deceleration intention determination unit 102 is affirmed during the coast downshift, that is, in a state where it is determined that there is a driver's intention to decelerate. Thus, the increase of the engagement pressure of the brake B1 is stopped to prevent the shift from proceeding, while the increase of the engagement pressure of the brake B1 is stopped so that the determination of the deceleration intention determination means 102 is performed. If NO is determined, that is, if it is determined that the driver does not intend to decelerate, the shift standby control is released, the engagement pressure of the brake B1 is increased again, and the shift is advanced again. In downshifting during coasting (coast), coasting down shift control is generally performed in preparation for the depression of the accelerator so that acceleration can be accelerated with an appropriate driving force when accelerating again. If the state in which the vehicle is affirmed, that is, the state in which it is determined that the driver intends to decelerate continues, the shift from the deceleration state to the vehicle stop state is conceivable. As a result, occurrence of shift shock can be suitably suppressed. On the other hand, in a case where the determination of the deceleration intention determination means 102 is denied, that is, a state where it is determined that the driver does not intend to decelerate, it is possible that the vehicle will start to re-accelerate from the time of deceleration. The coast down shift is advanced and finished, and the accelerator is depressed so that it can be accelerated with an appropriate driving force with good response. Here, in the control of the present embodiment, since the shift proceeds by releasing the brake operation, there is a possibility that the down shift is performed after the release, but the brake-off shock and the shift shock that are felt by the driver. Therefore, there is also an advantage that it is possible to suppress the driver from feeling it as a shift shock by overlapping the shift shock with the shock caused by the intentional brake-off operation.

  FIG. 10 is a time chart showing the torque of the output shaft 24 and the on / off state of the brake in the turning traveling state of the vehicle corresponding to the time chart of FIG. 9, and the output shaft torque by the control of this embodiment is shown by a solid line. The output shaft torque by conventional control that does not stop the increase in the engagement pressure of the brake B1 is indicated by dotted lines. When the vehicle is turning, it is highly likely that the accelerator pedal 50 is depressed and accelerated again immediately after the brake operation is released, but the coast down shift control is prevented from proceeding by the brake operation, In the aspect in which the coast down shift control is re-advanced together with the release of the brake operation, when the accelerator pedal 50 is depressed and re-accelerated immediately after the release of the brake operation, a solid line after time t3 ′ in FIG. As shown in FIG. 6, there is a possibility that the change width of the output shaft torque becomes large in a short time and a characteristic that a shift shock occurs slightly. Therefore, in this embodiment, as described above, when the determination of the turning determination means 108 is affirmative, that is, when the vehicle is in a turning traveling state, the engagement side hydraulic pressure supplied to the brake B1 without executing the shift standby control. To increase the shift. Thereby, the coast downshift from the 3rd speed to the 2nd speed is completed promptly as in the conventional control, and such a shift shock can be suppressed as shown by a dotted line in FIG.

Shift abort means 110, if the speed change standby control by the shift waiting means 104 during the coast downshift is not performed, as shown in FIG. 13, the elapsed time t _e from the start time for example the inertia phase start of coast downshift It is to kill the coast downshift when it reaches a preset normality compulsory end time T _B in a few seconds coastdown gear shift is finished at the time of normal. Further, the shift abort means 110, if the speed change standby control by the shift waiting means 104 is performed during the coast downshift, as shown in FIG. 14, the elapsed time t _e is the normal kill time T _B forcibly terminating coast downshift when the first has reached the shift standby control runtime abort time T ₁ which is set longer than. First shift standby control runtime abort time T ₁ are the time elapsed since only shift standby end time t ₄ predetermined time, for example the same length of time as the normal kill time T _B, inevitably the a value longer than the forced end time T _B normal.

In the case where the shift wait control by the shift waiting means 104 before the elapsed time t _e reaches a preset normal kill time T _B is performed, the shift abort means 110, the end of the shifting standby control point elapsed time t _4e from t ₄ was re counted may forcibly terminate the coast downshift upon reaching the predetermined time, substantially, the elapsed time t _e is ended first shift standby control performed during forced Once at the time T ₁ is the same as to kill the coast downshift.

Further, when the shift wait control by the shift waiting means 104 is performed, the shift abort means 110 includes a time when the elapsed time t _e has reached the time to kill time T ₁ first shift standby control execution, the when the elapsed time t _e has occurred either earlier with upon reaching normal kill time T second shift standby control runtime abort time set in advance longer than _B T _2, forcing the coast downshift Terminate. FIG. 15 shows that the elapsed time t _e reaches the preset second shift standby control execution forced end time T ₂ before the elapsed time t _e reaches the first shift standby control execution forced end time T _1. An example is shown in which the coast-down shift is forcibly terminated at the time when the occurrence occurs earlier. Said second speed change standby control runtime abort time T ₂ are, coast downshift which when executed repeatedly shift standby control related to the brake operation is finished the coast down shift is set as a countermeasure for that prolonged considerably For example, a value of about 30 seconds is preset.

  FIGS. 11 and 12 are flowcharts for explaining the main part of the control operation by the electronic control unit 90, FIG. 11 is for explaining the main part of the coast down shift control operation, and FIG. This routine includes a plurality of steps corresponding to the forcible end means 110, and is for explaining a main part of the forced end control operation of the coast down shift. 11 and 12 are repeatedly executed at a relatively short cycle of several ms to several tens of ms.

First, in step (hereinafter, step is omitted) S1, it is determined whether or not a coast downshift is being performed, that is, whether or not it is a downshift during coasting (coast). If the determination in S1 is negative, the routine is terminated. If the determination in S1 is affirmative, the driver's intention to decelerate is determined in S2 corresponding to the operation of the deceleration intention determination means 102. It is determined whether or not there is. For example, when the brake contact signal is turned on based on ON / OFF of the brake contact signal of the foot brake detected via the brake sensor 70, the brake master cylinder pressure not shown, or the like, or the brake master cylinder pressure Is greater than or equal to a predetermined value, it is determined that the driver intends to decelerate. Further, when the brake contact signal is turned off, or when the brake master cylinder pressure becomes a predetermined value or less, or based on the operation amount Acc of the accelerator pedal 50 detected via the accelerator operation amount sensor 52, etc. When the accelerator operation amount Acc is not zero, that is, when the engine 30 is not in the idle state, it is determined that there is no intention to decelerate. Further, based on the change rate (change amount per predetermined time) of the foot brake depression amount θ _SC detected via the brake sensor 70, the change rate of the brake master cylinder pressure (not shown), etc., the brake depression amount θ _{When the SC} change rate is less than or equal to a predetermined value or when the brake master cylinder pressure change rate is less than or equal to a predetermined value, it is determined that the brake operation release speed is greater than or equal to a predetermined value. It is judged that there is no. If the determination in S2 is negative, that is, if it is determined that the driver does not intend to decelerate, the engagement is made via the hydraulic control circuit 98 in S4 corresponding to the operation of the shift advancement means 106. This routine is terminated after the engagement-side hydraulic pressure supplied to the hydraulic friction engagement device on the side is increased and coast-down shift control is resumed, but when the determination in S2 is affirmative, that is, If it is determined that the driver intends to decelerate, in S3 corresponding to the operation of the turning determination means 108, it is determined whether or not the vehicle is in a turning state (turning). For example, based on whether or not the steering wheel or wheel steering angle, lateral acceleration (lateral G), corner R, etc. detected by a sensor (not shown) exceeds a predetermined criterion value, the criterion is exceeded. In this case, it is determined that the vehicle is turning. Further, if the accelerator return speed excluding the tip-in operation is greater than or equal to a predetermined value during acceleration orientation, or if the deceleration during braking is greater than or equal to a predetermined value, it is determined that the vehicle is turning. If the determination in S3 is affirmative, the processes in and after S4 are executed. If the determination in S3 is negative, in S5 corresponding to the operation of the shift standby means 104, the hydraulic control circuit After the engagement-side hydraulic pressure supplied to the engagement-side hydraulic friction engagement device via 98 is stopped and the shift is not allowed to proceed, this routine is terminated.

  The forced termination operation of the coast down shift will be described with reference to the flowchart of FIG. 12 and the time charts of FIGS. FIG. 13 is a time chart for explaining the forced termination operation when the shift standby control based on the driver's intention to decelerate is not performed within the coast down shift period, and FIG. 14 is the time chart of the driver from the beginning within the coast down shift period. FIG. 15 is a time chart for explaining the forced termination operation when the shift standby control based on the intention to decelerate is performed. FIG. 15 shows that the shift standby control based on the driver's intention to decelerate is performed from the beginning within the coast down shift period. It is a time chart explaining the forced termination operation when it is once terminated and the shift standby control is performed again.

  FIG. 12 is a flowchart that is executed when the coast down shift period is forcibly terminated to prevent the coast down shift period from being prolonged for some reason, and the coast down shift determination is performed. In FIG. 12, first in SA1, a coast down shift is started. That is, the release side frictional engagement element is commanded to be released, the engagement side frictional engagement element is commanded to be engaged, and the coasting down shift is started. This state is shown at time t1 in FIGS. Next, at SA2, during the coast downshift, for example, whether any one of the determinations (a), (b), and (c) above is affirmed and the start condition of the shift standby control based on the occurrence of the deceleration intention is satisfied. It is determined whether or not.

As shown in FIG. 13, when the shift standby control is not performed during the coast down shift, the determination of SA2 is denied, so whether or not there is a history that the shift standby control has been performed since the start of the shift in SA3. Is judged. Since the deny determination in SA3, in SA4, whether the elapsed time t _e, which is counted from the time t2 indicating the start of the inertia phase exceeds a preset normality compulsory end time T _B is determined . Since the determination at SA4 is initially denied, SA2, SA3, and SA4 are repeatedly executed. If the determination of SA4 is affirmed among the repetitions, if the coast down shift is still continued in SA5 corresponding to the shift forced termination means 110, the forced termination is executed and this routine is terminated. This state is shown at time t3 in FIG.

As shown in FIGS. 14 and 15, when the shift standby control is performed during the coast down shift, if the shift standby control is being executed, the determination of SA2 is affirmed. Therefore, in SA6, the elapsed time t _e whether reaches T ₂ preset second speed change standby control runtime kill time is determined. While this determination is denied, there is a high probability that the coast-down shift is still in progress, so SA2 and SA6 are repeatedly executed. If the determination of SA6 is affirmed in this state, the coast down shift that is continued in SA5 corresponding to the forced shift end means 110 is forcibly ended.

However, if the determination at SA2 is negative, since the state after the shift standby control is finished, it is determined at SA3 that there is a history that the shift standby control has been performed from the start of the shift. , whether the elapsed time t _e has reached the second speed change standby control runtime abort time T ₂ that has been set in advance it is determined. Since initially the determination in SA7 is negative, the SA8, first whether reaches the speed change standby control runtime abort time T ₁ to the elapsed time t _e is set in advance is determined. Initially, the determination of SA8 is also denied, so SA2, SA3, SA7, and SA8 are repeatedly executed. That is, the SA7 and SA8, and when the elapsed time t _e has reached the second speed change standby control runtime abort time T ₂ set in advance, the first time shift standby control execution of the elapsed time t _e is set in advance earlier time of ones of the time when the forced termination time reaches T ₁ is is determined.

While SA2, SA3, SA7, and SA8 are repeatedly executed, as shown in FIG. 14, when the number or period of the shift standby control performed during the coast downshift is relatively small or short, the SA8 is performed. Is affirmed, the coast down shift that is being continued in SA5 corresponding to the forced shift end means 110 is forcibly ended. The time t5 in FIG. 14 shows this state. Also, when SA2, SA3, SA7, and SA8 are repeatedly executed, as shown in FIG. 15, when the number of shift standby control performed during the coast downshift or the total period is relatively long or long, Since the determination of SA7 is affirmed, the coast down shift that is continuing in SA5 corresponding to the forced shift end means 110 is forcibly ended. This state is shown at time t7 in FIG. Note that in FIG. 14 and FIG. 15, dashed line actually shows the normal kill time T _B and the first speed change standby control runtime abort time T ₁ that has not been used.

As described above, according to this embodiment, by shifting abort means 110, if the speed change standby control by the shift waiting means 104 is not executed, the elapsed time t _e from the shift start or beginning of the inertia phase of coast downshift since it is forced to terminate the coast downshift when it reaches a preset normality compulsory end time T _B, at the time when the speed change standby control is not performed, excessive prolonged coastdown shift is as much as possible When the shift standby control by the shift standby means 104 is executed by the shift forced end means 110, the progress is prevented. force the coast downshift when the time t _e has reached the first speed change standby control runtime abort time T ₁ which is set longer than the normal kill time T _B Since it is allowed to completion, the shift standby control during the coast downshift is also performed, deterioration of the durability of the engagement side frictional engagement element to perform its coast downshift is suppressed.

Further, according to the present embodiment, when the shift standby control is executed by the shift standby unit 104, the forced shift end unit 110 starts the inertia phase when a predetermined time has elapsed from the end of the shift standby control. from since it is intended to forcibly terminate coast downshift when first reaching the shift standby control runtime abort time T _1, at the time when the speed change standby control is performed during coast downshift, the coast downshift Unnecessary lengthening is prevented as much as possible, and a decrease in durability of the engagement side frictional engagement element is prevented as much as possible. The predetermined time is, since it is the same length as the normal kill time T _B, is easily set.

Further, according to this embodiment, the shift abort means 110, the elapsed time t _e is the gear stand first from time i.e. the inertia phase start predetermined time has elapsed from the end of the control shift standby control runtime abort time T and upon reaching _1, when whichever occurred among the time of reaching the second shift standby control runtime abort time T ₂ that has been set in advance, since those which kill the coast downshift, Longer coast down shifting is reliably prevented, and a decrease in durability of the engagement side frictional engagement element is preferably prevented.

  Further, according to the present embodiment, the determination of the deceleration intention determination unit 102 (S2) that determines whether or not the driver intends to decelerate during the coast downshift and the determination of the deceleration intention determination unit 102 are affirmed. In this case, the increase in the engagement pressure of the engagement side frictional engagement element is stopped to prevent the shift from proceeding, and the shift standby unit 104 increases the engagement pressure. In the stopped state, if the determination by the deceleration intention determination unit 102 is negative, the shift advancement unit 106 (S4) that increases the engagement pressure of the engagement side frictional engagement element again to advance the shift. Therefore, when the driver intends to decelerate, i.e., when it is considered that the driver intends to shift from the deceleration state to the stop state, it is unnecessary to prevent the coast down shift from proceeding. In addition to being able to prevent such a coastdown shift by shift shock occurs, if no longer deceleration intention of the driver by advancing the coast downshift, can be accelerated well response when accelerating again during deceleration. That is, it is possible to provide a shift control device for the automatic transmission 10 for a vehicle that can reduce a shift shock while enabling acceleration with good response when the vehicle is accelerated again from the time of deceleration.

  Further, the friction engagement element is a hydraulic friction engagement device, and the shift standby unit 104 is configured to perform the hydraulic friction engagement on the engagement side when the determination of the deceleration intention determination unit 102 is affirmed. The increase of the engagement side hydraulic pressure supplied to the apparatus is stopped so as not to proceed with the shift, and the shift progress means 106 determines that the engagement is determined when the determination of the deceleration intention determination means 102 is negative. A practical automatic transmission for a vehicle having a plurality of hydraulic friction engagement devices, because the engagement hydraulic pressure supplied to the combined hydraulic friction engagement device is increased again to advance the shift. 10, it is possible to reduce the shift shock while enabling acceleration with good response when accelerating again from the time of deceleration of the vehicle.

  In addition, the deceleration intention determination unit 102 determines whether the driver has released the brake operation, the accelerator operation, or the release speed of the brake operation amount is a predetermined value or more. Therefore, the presence or absence of the driver's intention to decelerate can be suitably determined.

  Further, the vehicle has a turning determination unit 108 (S3) for determining whether or not the vehicle is turning, and the shift standby unit 104 is conditioned on the condition that the determination of the turning determination unit 108 is negative. Since the increase of the engagement pressure of the engagement frictional engagement element is stopped to prevent the shift from proceeding, when the vehicle is turning, immediately after the brake operation is performed for turning. Since there is a high possibility that the vehicle will be accelerated again, it is possible to suitably suppress deterioration in acceleration during such re-acceleration.

  Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented with various modifications without departing from the spirit of the present invention.

For example, in the above-described embodiment, the elapsed time t _e , the normal forced end time T _B , the first shift standby control execution forced end time T ₁ , and the second shift standby control execution forced end time T ₂ are the The start of the downshift inertia phase is used as a reference. Alternatively, the start of a shift such as a shift output judgment of the coast downshift or a shift output may be used as a reference.

In the illustrated embodiments, the first speed change standby control runtime abort time T ₁ is added normal kill time T _B the same length of time as the predetermined time Ji time elapsed from the shift standby end time t ₄ Although the a time, may not necessarily be the same as the predetermined time is normal kill time T _B, may be used is shorter value or longer than normal kill time T _B.

  In the above-described embodiment, the automatic transmission 10 has a plurality of hydraulic friction engagement devices as friction engagement elements for establishing a plurality of gear stages having different gear ratios by selective engagement. In other words, the clutch C and the brake B were provided, but the present invention is not limited to this, and for example, it is provided with a friction engagement element by electromagnetic control such as an electromagnetic clutch or a magnetic powder clutch. There may be. In this case, the shift standby unit 104 and the shift progression unit 106 control the engagement pressures of the friction engagement elements by controlling command signals supplied to the friction engagement elements.

  In the above-described embodiment, the release pressure of the release-side hydraulic friction engagement device and the engagement pressure of the engagement-side hydraulic friction engagement device are directly applied using the linear solenoid valves SL1 to SL6. Although direct pressure control for performing downshifting by control has been described, a linear solenoid valve is not provided corresponding to each hydraulic friction engagement device, and other control methods are not direct pressure control. The present invention is also suitably applied to a speed change mechanism that uses this hydraulic control circuit.

  In the above-described embodiment, as an example of the coast downshift gear shift, the control including the third gear → second gear and the third gear → first gear downshift without passing through the second gear stage, that is, the one-way clutch gear shift, has been described. The present invention is widely applied to coast-down gear shifting by switching between a disengagement side frictional engagement element and an engagement side frictional engagement element when a vehicle is decelerated. Needless to say, the present invention is also preferably applied.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle automatic transmission to which the present invention is preferably applied. 2 is an operation table for explaining the operation of a friction engagement element when a plurality of shift speeds are established in the automatic transmission of FIG. 1. FIG. 3 is a collinear diagram that can represent the rotational speeds of the rotating elements of the first transmission unit and the second transmission unit provided in the automatic transmission of FIG. 1 by straight lines. FIG. 2 is a block diagram illustrating a main part of a control system provided in the vehicle for controlling the automatic transmission of FIG. 1 and the like. It is a figure explaining the operation position of the shift lever of FIG. It is a figure which shows an example of the shift map used in the shift control of the electronic controller of FIG. It is a figure explaining the principal part of the hydraulic control circuit of FIG. FIG. 5 is a functional block diagram illustrating a main part of a control function of the electronic control device of FIG. FIG. 5 is a time chart for explaining a hydraulic pressure command value corresponding to a hydraulic friction engagement device on the engagement side in a third speed → second speed downshift as an example of coast down shift control operation by the electronic control unit of FIG. In this example, the driver decelerates and the vehicle is reaccelerated. FIG. 10 is a time chart showing the output shaft torque and on / off of the brake in a turning state of the vehicle corresponding to the time chart of FIG. 9, and the output shaft torque by the control of the present invention is shown by a solid line, and the hydraulic friction on the engagement side The output shaft torque by the conventional control that does not stop the increase in the engagement pressure of the engagement device is shown by dotted lines. 6 is a flowchart for explaining a main part of a coast down shift control operation by the electronic control unit of FIG. 6 is a flowchart for explaining a main part of a forced end control operation of coast down shift control by the electronic control unit of FIG. It is a time chart explaining the shift forced termination control operation in the case of a coast down shift when the shift standby control is not performed. It is a time chart explaining the shift forced termination control operation when shift standby control is performed during coast down shift. 6 is a time chart illustrating a shift forced end control operation when shift standby control is performed a plurality of times during a coast down shift.

Explanation of symbols

10: automatic vehicular transmission 100: shift control means 102: deceleration intention judging means 104: shift waiting means 106: shift change unit 110: transmission abort means _{T B:} normal kill time _{T 1:} first transmission wait control Forced termination time during execution (forced termination time)
T ₂ : Forced end time during execution of second shift standby control (forced end time)
B1, B2: Brake (friction engagement element, hydraulic friction engagement device)
C1, C2, C3, C4: Clutch (friction engagement element, hydraulic friction engagement device)

Claims (4)

In a vehicular automatic transmission that establishes a plurality of gear stages having different gear ratios by selectively engaging a plurality of friction engagement elements, a release-side friction engagement element and an engagement-side friction engagement during vehicle deceleration A shift control device for an automatic transmission for a vehicle that performs a coast down shift by re-engaging with an element,
Deceleration intention determination means for determining whether or not there is a driver's intention to decelerate during the coast down shift,
A shift standby means for executing a shift standby control for stopping the increase in the engagement pressure of the engagement side frictional engagement element and not allowing the shift to proceed when the determination of the deceleration intention determination means is affirmative;
In a state where the increase in the engagement pressure is stopped by the shift standby unit, if the determination of the deceleration intention determination unit is negative, the shift standby control is canceled and the engagement side frictional engagement element is released. Shift advancement means for increasing the engagement pressure again to advance the shift;
When the shift standby control is not executed by the shift standby means, the coast down shift is forced when the elapsed time from the start of the coast down shift or the start of the inertia phase reaches a preset normal time compulsory end time. On the other hand, when the shift standby control is executed by the shift standby means, the coast down shift is forced when the elapsed time reaches the forced end time set longer than the normal time forced end time. A shift control device for an automatic transmission for a vehicle, comprising: a forced shift end means for ending. 2. The shift down forcibly terminating means forcibly terminates the coast down shift when a predetermined time has elapsed from the end of the shift standby control when the shift standby control is executed by the shift standby means. Shift control device for automatic transmission for vehicles. The shift control device for an automatic transmission for a vehicle according to claim 2, wherein the predetermined time is the same as the normal forced end time. The forced shift end means has an elapsed time whichever comes first when the predetermined time has elapsed from the end of the shift standby control or when a predetermined shift standby control execution end time is reached. The shift control device for an automatic transmission for a vehicle according to claim 2 or 3, wherein the coast down shift is forcibly terminated when it occurs.

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