JP2013167331A - Transmission control device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently control occurrence of any shock when down-shifting a speed change stage by changing a friction engagement element of a transmission in an accelerator-on condition from an engagement state to a disengagement state.SOLUTION: A speed change ECU 21 sets a hydraulic pressure command value Psl(j)* to a disengagement element by feedback control so that the rotational acceleration dNin of an input shaft 26 may reach a target rotational acceleration dNintag after rotational change of the input shaft 26 is started, and the inertia phase control is performed when executing the down-shift of a speed change stage in an accelerator-on stage (Step S420), and sets the hydraulic pressure command value Psl(j)* so that the hydraulic pressure on the disengagement element may be increased compared with the case when the remaining speed change time tsr is equal to or more than the determination time tref when the remaining speed change time tsr at the setting start of the hydraulic pressure command value Psl(j)* by the feedback control is below the determination time tref (Steps S416, S420).

Description

  The present invention relates to a control device and a control method for a transmission that have a plurality of friction engagement elements that are operated by hydraulic pressure from a hydraulic control device and that can transmit power applied from a prime mover to an input shaft to an output shaft.

  Conventionally, as a control device for this type of transmission, in a power-on (accelerator-on) state, at least one of a plurality of friction engagement elements is switched from an engagement state to a release state to change the speed. When downshifting a gear, there is known one that sequentially executes standby control, initial shift control, inertia phase control, feedback control, and completion control (see, for example, Patent Document 1). This control device sweeps down the hydraulic pressure command value to the release element with a relatively low gradient when the change amount of the input rotation speed with respect to the output rotation speed exceeds the shift start determination rotation speed during execution of the initial shift control. Inertia phase control starts. In the power-on state, the inertia phase control is performed until the change amount of the input rotation speed with respect to the output rotation speed becomes aF% of the total rotation speed change amount from the start of the shift (start of the rotation change) to the completion of the shift. The command value of the hydraulic pressure to the release element is set by feedback control so that the change amount of the input shaft rotation speed becomes the predetermined change amount until the change amount of the input rotation speed with respect to the rotation speed becomes close to the total rotation speed change amount. The

Japanese Patent Laid-Open No. 11-141647

  As in the conventional example, when the shift stage is downshifted in the accelerator-on state, the command value of the hydraulic pressure to the release element is set by the feedback control as described above after the start of the rotation change of the input shaft. It is possible to suppress the steep change in the rotation of the input shaft by gradually increasing the supplied hydraulic pressure. However, there is a time lag until the hydraulic pressure responds to the command value, and if the effect of the feedback control cannot be obtained quickly, the increase in the hydraulic pressure to the release element is delayed, causing the rotation change of the input shaft. There is a risk that the torque will be steep and the torque output to the output shaft will increase suddenly, causing a shock just before the end of shifting.

  SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to satisfactorily suppress the occurrence of shock when the shift stage is downshifted by switching the frictional engagement element of the transmission from the engaged state to the released state in the accelerator-on state. .

  The transmission control device and the control method of the present invention employ the following means in order to achieve the main object.

A transmission control apparatus according to the present invention includes:
In a control device for a transmission having a plurality of friction engagement elements that are operated by hydraulic pressure from a hydraulic control device and capable of transmitting power applied from a prime mover to an input shaft to an output shaft,
The hydraulic pressure that generates hydraulic pressure to the release element when the release element, which is at least one of the plurality of friction engagement elements, is switched from the engagement state to the release state to downshift the shift stage. A release control means for setting a hydraulic pressure command value to the control device;
The release control means performs the hydraulic control by feedback control so that the rotational acceleration of the input shaft becomes the target rotational acceleration after the rotational change of the input shaft is started when the shift stage is downshifted in an accelerator-on state. The command value is set, and when the remaining shift time at the start of setting the hydraulic pressure command value by the feedback control is less than the determination time, the release element is compared with the case where the remaining shift time is equal to or longer than the determination time. The hydraulic pressure command value is set so that the hydraulic pressure increases.

  This transmission control device uses a feedback control to control the hydraulic pressure command value so that the rotational acceleration of the input shaft becomes the target rotational acceleration after the rotational change of the input shaft is started when the shift stage is downshifted with the accelerator on. Set. In this control device, when the remaining shift time at the start of setting the hydraulic pressure command value by feedback control is less than the determination time, the hydraulic pressure to the release element is larger than when the remaining shift time is longer than the determination time. The hydraulic pressure command value is set so that it is raised. In other words, if the remaining shift time at the start of setting of the hydraulic pressure command value by feedback control is short, it may be just before the end of downshift before the effect of feedback control is obtained. As the width is smaller, it is difficult to obtain the effect of feedback control. On the other hand, if the hydraulic pressure command value is set so that the hydraulic pressure to the release element is increased when the remaining shift time is less than the determination time, the torque capacity of the release element is increased and the release element slips. As a result, it is possible to suppress a sudden increase in torque output to the output shaft while moderating the rotational change of the input shaft. Therefore, according to this control device, it is possible to satisfactorily suppress the occurrence of a shock when the shift stage is downshifted in the accelerator-on state. Note that when the setting of the hydraulic pressure command value by feedback control is started, the remaining speed is changed after the start of setting of the hydraulic pressure command value by feedback control (after a relatively short time) and due to an increase in rotational change (rotational acceleration) of the input shaft. It may include when the time is shortened.

  In the feedback control, the hydraulic pressure command value is set by adding a feedback term based on the rotational acceleration of the input shaft and the target rotational acceleration to the previous setting value of the hydraulic pressure command value every predetermined time. The release control means may be configured to increase the hydraulic pressure to the release element when the remaining shift time at the start of setting the hydraulic pressure command value by the feedback control is less than the determination time. The previously set value may be changed only once. As a result, it is possible to more appropriately increase the hydraulic pressure to the release element while leaving room for obtaining the effect of feedback control after the change of the previous set value.

  Further, when the remaining shift time at the start of setting of the hydraulic pressure command value by the feedback control is less than the determination time, the release control means sets the previous set value according to the input torque applied to the input shaft. It may be a value. This makes it possible to make the increase in the torque capacity of the release element due to the change of the set value last time more appropriate.

  The determination time may be set to a value corresponding to a rotation speed of the output shaft and a shift pattern of the shift stage. Accordingly, the determination time can be set in consideration of the rotation change (rotational acceleration) of the input shaft according to the rotation speed (vehicle speed) of the output shaft and the shift pattern (downshift pattern). When starting to set the hydraulic pressure command value, it is possible to more appropriately determine whether or not the effect of feedback control can be obtained.

  Further, the setting of the hydraulic pressure command value by the feedback control may be started when the rotation change of the input shaft is started and the shift progress degree based on the rotation change amount of the input shaft exceeds a predetermined value. Good.

The transmission control method according to the present invention is a transmission control method that includes a plurality of friction engagement elements that are operated by hydraulic pressure from a hydraulic control device and that can transmit power applied from the prime mover to the input shaft to the output shaft. ,
The hydraulic pressure that generates hydraulic pressure to the release element when the release element, which is at least one of the plurality of friction engagement elements, is switched from the engagement state to the release state to downshift the shift stage. Including a release pressure setting step for setting a hydraulic pressure command value to the control device,
The release pressure setting step is performed by feedback control so that the rotational acceleration of the input shaft becomes the target rotational acceleration after the rotational change of the input shaft is started when the shift stage is downshifted in an accelerator-on state. Setting the hydraulic pressure command value and releasing the release time when the remaining shift time at the start of setting the hydraulic pressure command value by the feedback control is less than the determination time compared to when the remaining shift time is greater than or equal to the determination time The hydraulic pressure command value is set so that the hydraulic pressure to the element is raised.

  According to this method, when the remaining shift time at the start of setting the hydraulic pressure command value by feedback control is less than the determination time and it is difficult to obtain the effect of feedback control, the rotational change of the input shaft is moderated and the output shaft Therefore, it is possible to suppress the occurrence of shock when the shift stage is downshifted in the accelerator-on state.

It is a schematic block diagram of the motor vehicle 10 carrying the power transmission device 20 containing the automatic transmission 25 controlled by the control apparatus by this invention. FIG. 2 is a schematic configuration diagram showing a power transmission device 20. 3 is an operation table showing a relationship between each gear position of the automatic transmission 25 and operation states of clutches and brakes. 2 is a system diagram showing a hydraulic control device 50. FIG. It is a flowchart which shows an example of the release control routine performed by transmission ECU21 which is a control apparatus by this invention. It is a time chart which illustrates a mode that various parameters change when a release control routine is performed. 6 is a flowchart illustrating an example of a rotation change rate control routine included in the release control routine of FIG. 5.

  Next, embodiments of the present invention will be described using examples.

  FIG. 1 is a schematic configuration diagram of an automobile 10 equipped with a power transmission device 20 including an automatic transmission 25 controlled by a control device according to the present invention. An automobile 10 shown in the figure includes an engine (internal combustion engine) 12 as a prime mover that outputs power by explosion combustion of a mixture of hydrocarbon fuel such as gasoline and light oil and air, and an engine electronic for controlling the engine 12. A control unit (hereinafter referred to as “engine ECU”) 14, a brake electronic control unit (hereinafter referred to as “brake ECU”) 16 for controlling an electronically controlled hydraulic brake unit (not shown) 16, and an engine 12 are connected to the engine 12. Including a power transmission device 20 that transmits power from the left and right drive wheels DW. The power transmission device 20 includes a transmission case 22, a fluid transmission device (torque converter) 23, an automatic transmission 25, a hydraulic control device 50, and a shift electronic control unit (hereinafter, “ 21) and the like.

  The engine ECU 14 is configured as a microcomputer centering on a CPU (not shown). In addition to the CPU, a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, and a communication port (all not shown). Etc.). As shown in FIG. 1, the engine ECU 14 includes an accelerator opening Acc from an accelerator pedal position sensor 92 that detects a depression amount (operation amount) of an accelerator pedal 91, a vehicle speed V from a vehicle speed sensor 97, and a rotational position of a crankshaft. A signal from various sensors such as a crankshaft position sensor (not shown) for detecting the engine, a signal from the brake ECU 16 and the shift ECU 21 and the like are input, and the engine ECU 14 is based on these signals and is an electronically controlled throttle valve (not shown). Control the fuel injection valve and spark plug. Further, the engine ECU 14 calculates the rotational speed Ne of the engine 12 based on the rotational position of the crankshaft detected by the crankshaft position sensor, and for example, the intake of the engine 12 detected by the rotational speed Ne or an air flow meter (not shown). An estimated engine torque Test, which is an estimated value of the torque output from the engine 12, is calculated based on the air amount, the throttle opening THR of the throttle valve, and a predetermined map or calculation formula.

  The brake ECU 16 is also configured as a microcomputer centering on a CPU (not shown). In addition to the CPU, a ROM for storing various programs, a RAM for temporarily storing data, an input / output port and a communication port (none of which are shown). ) Etc. As shown in FIG. 1, the brake ECU 16 receives the master cylinder pressure Pmc detected by the master cylinder pressure sensor 94 when the brake pedal 93 is depressed, the vehicle speed V from the vehicle speed sensor 97, various sensors (not shown), and the like. Signals, signals from the engine ECU 14 and the shift ECU 21 and the like are input, and the brake ECU 16 controls a brake actuator (hydraulic actuator) (not shown) based on these signals.

  The speed change ECU 21 is also configured as a microcomputer centered on a CPU (not shown). In addition to the CPU, a ROM that stores various programs, a RAM that temporarily stores data, an input / output port, and a communication port (all not shown). ) Etc. As shown in FIG. 1, the shift ECU 21 detects the operation position of the shift lever 95 for selecting a desired shift range from the accelerator opening Acc from the accelerator pedal position sensor 92 and a plurality of shift ranges. A rotational speed sensor 98 for detecting a shift range SR from the range sensor 96, a vehicle speed V from the vehicle speed sensor 97, an input rotational speed of the automatic transmission 25 (the rotational speed of the turbine runner 23b or the input shaft 26 of the automatic transmission 25) Nin. In addition, signals from various sensors such as an oil temperature sensor 99 for detecting the oil temperature Toil of the hydraulic oil in the hydraulic control device 50, signals from the engine ECU 14 and the brake ECU 16, and the like are input, and the transmission ECU 21 is based on these signals. The fluid transmission device 23 and the automatic transmission 25, that is, the hydraulic control device 50 are controlled.

  As shown in FIG. 2, the fluid transmission device 23 of the power transmission device 20 is connected to an input-side pump impeller 23 a connected to the crankshaft of the engine 12 and an input shaft (input member) 26 of the automatic transmission 25. The output side turbine runner 23b and the lockup clutch 23c are included. The oil pump 24 is configured as a gear pump including a pump assembly including a pump body and a pump cover, and an external gear connected to the pump impeller 23a of the fluid transmission device 23 via a hub. When the external gear is rotated by the power from the engine 12, the hydraulic oil (ATF) stored in the oil pan (not shown) is sucked by the oil pump 24 and is pumped to the hydraulic control device 50.

  The automatic transmission 25 is configured as a six-speed transmission, and as shown in FIG. 2, a single pinion planetary gear mechanism 30, a Ravigneaux planetary gear mechanism 35, and an input side to an output side. It includes three clutches C1, C2 and C3, two brakes B1 and B2 and a one-way clutch F1 for changing the power transmission path. The single pinion type planetary gear mechanism 30 includes a sun gear 31 that is an external gear fixed to the transmission case 22, and a ring gear 32 that is disposed on a concentric circle with the sun gear 31 and connected to the input shaft 26. And a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, and a carrier 34 that holds the plurality of pinion gears 33 so as to rotate and revolve.

  The Ravigneaux planetary gear mechanism 35 meshes with two sun gears 36a and 36b that are external gears, a ring gear 37 that is an internal gear fixed to the output shaft (output member) 27 of the automatic transmission 25, and the sun gear 36a. A plurality of short pinion gears 38a, a plurality of long pinion gears 38b meshed with the sun gear 36b and the plurality of short pinion gears 38a and meshed with the ring gear 37, and a plurality of short pinion gears 38a and a plurality of long pinion gears 38b coupled to each other. And a carrier 39 supported by the transmission case 22 via a one-way clutch F1. The output shaft 27 of the automatic transmission 25 is connected to the drive wheels DW via a gear mechanism 28 and a differential mechanism 29.

  The clutch C1 has a hydraulic servo including a plurality of friction plates, a counter plate, an oil chamber to which hydraulic oil is supplied, and the like. The carrier 34 of the single pinion planetary gear mechanism 30 and the sun gear of the Ravigneaux planetary gear mechanism 35 are provided. This is a multi-plate friction type hydraulic clutch (friction engagement element) capable of fastening 36a and releasing the fastening of both. The clutch C2 has a hydraulic servo composed of a plurality of friction plates, a counter plate, an oil chamber to which hydraulic oil is supplied, and the like, which fastens the input shaft 26 and the carrier 39 of the Ravigneaux type planetary gear mechanism 35. This is a multi-plate friction type hydraulic clutch that can release the engagement of the clutch. The clutch C3 has a hydraulic servo constituted by a plurality of friction plates, a counter plate, an oil chamber to which hydraulic oil is supplied, and the like, and the carrier 34 of the single pinion planetary gear mechanism 30 and the sun gear of the Ravigneaux planetary gear mechanism 35. This is a multi-plate friction hydraulic clutch capable of fastening 36b and releasing the fastening of both.

  The brake B1 is configured as a band brake or a multi-plate friction brake including a hydraulic servo, and fixes the sun gear 36b of the Ravigneaux type planetary gear mechanism 35 to the transmission case 22 and releases the fixation of the sun gear 36b to the transmission case 22. It is a hydraulic brake that can. The brake B2 is configured as a band brake or a multi-plate friction brake including a hydraulic servo, and fixes the carrier 39 of the Ravigneaux type planetary gear mechanism 35 to the transmission case 22 and releases the fixing of the carrier 39 to the transmission case 22. It is a hydraulic brake that can.

  These clutches C <b> 1 to C <b> 3 and brakes B <b> 1 and B <b> 2 operate by receiving and supplying hydraulic oil from the hydraulic control device 50. FIG. 3 shows an operation table showing the relationship between the respective shift stages of the automatic transmission 25 and the operation states of the clutches C1 to C3 and the brakes B1 and B2. The automatic transmission 25 provides the first to sixth forward speeds and the first reverse speed by setting the clutches C1 to C3 and the brakes B1 and B2 to the states shown in the operation table of FIG.

  FIG. 4 is a system diagram showing the hydraulic control device 50. The hydraulic control device 50 is connected to the above-described oil pump 24 that is driven by the power from the engine 12 and sucks and discharges hydraulic oil from the oil pan, and is requested by the fluid transmission device 23 and the automatic transmission 25. The hydraulic oil is generated and hydraulic oil is supplied to lubricated parts such as various bearings. As shown in FIG. 4, the hydraulic control device 50 adjusts the hydraulic oil from the oil pump 24 to generate the line pressure PL, and from the primary regulator valve 51 according to the operation position of the shift lever 95. The manual valve 52 for switching the supply destination of the line pressure PL, the apply control valve 53, and the hydraulic pressure to the corresponding clutch by adjusting the line pressure PL as the original pressure supplied from the manual valve 52 (primary regulator valve 51). Including a first linear solenoid valve SL1, a second linear solenoid valve SL2, a third linear solenoid valve SL3, a fourth linear solenoid valve SL4, and the like as pressure regulating valves for generating

  The primary regulator valve 51 is controlled by the speed change ECU 21 and supplies hydraulic oil from the oil pump 24 side (for example, a modulator valve that regulates the line pressure PL and outputs a constant hydraulic pressure) to an accelerator opening Acc or a throttle valve (not shown). It is driven by the hydraulic pressure from the linear solenoid valve SLT that regulates pressure according to the degree.

  The manual valve 52 is connected to the shift lever 95 in the axially slidable spool, the input port to which the line pressure PL is supplied, the input port of the first to fourth linear solenoid valves SL1 to SL4 and the oil passage. A drive range output port, a reverse range output port, and the like communicating with each other (both not shown). When the forward driving shift range such as the drive range or the sports range is selected by the driver, the input port is communicated only with the drive range output port by the spool of the manual valve 52, thereby the first to fourth linear solenoid valves SL1. The line pressure PL as the drive range pressure is supplied to ~ SL4. Further, when the reverse range is selected by the driver, the input port is communicated only with the reverse range output port by the spool of the manual valve 52. Further, when the parking range or neutral range is selected by the driver, the communication between the input port, the drive range output port, and the reverse range output port is blocked by the spool of the manual valve 52.

  The apply control valve 53 supplies the hydraulic pressure from the third linear solenoid valve SL3 to the clutch C3, the line pressure PL from the primary regulator valve 51 to the clutch C3, and the reverse range output port of the manual valve 52. The second state in which the line pressure PL (reverse range pressure) is supplied to the brake B2, and the line pressure PL (reverse range pressure) from the reverse range output port of the manual valve 52 is supplied to the clutch C3 and the brake B2. The spool valve can selectively form a third state and a fourth state in which the hydraulic pressure from the third linear solenoid valve SL3 is supplied to the brake B2.

  The first linear solenoid valve SL1 is a normally closed linear solenoid valve that adjusts the line pressure PL from the manual valve 52 according to the applied current to generate the hydraulic pressure Psl1 to the clutch C1. The second linear solenoid valve SL2 is a normally closed linear solenoid valve that adjusts the line pressure PL from the manual valve 52 according to the applied current to generate the hydraulic pressure Psl2 to the clutch C2. The third linear solenoid valve SL3 is a normally closed linear solenoid valve that adjusts the line pressure PL from the manual valve 52 according to the applied current to generate the hydraulic pressure Psl3 to the clutch C3 or the brake B2. The fourth linear solenoid valve SL4 is a normally closed linear solenoid valve that adjusts the line pressure PL from the manual valve 52 according to the applied current to generate the hydraulic pressure Psl4 to the brake B1. That is, the hydraulic pressures to the clutches C1 to C3 and the brakes B1 and B2, which are friction engagement elements of the automatic transmission 25, correspond to the first, second, third, or fourth linear solenoid valve pressures SL1, SL2, respectively. Directly controlled (set) by SL3 or SL4.

  The above-described first to fourth linear solenoid valves SL1 to SL4 (currents applied thereto) are controlled by the transmission ECU 21. That is, the speed change ECU 21 changes the gear position, that is, the target corresponding to the accelerator opening degree Acc (or the opening degree of the throttle valve) and the vehicle speed V, which are obtained from a predetermined speed change diagram (not shown) when upshifting or downshifting. To one of the first to fourth linear solenoid valves SL1 to SL4 corresponding to the clutch or brake (engagement element) that is engaged with the change of the shift speed so that the shift speed γtag is formed. To one of the first to fourth linear solenoid valves SL1 to SL4 corresponding to the hydraulic pressure command value (engagement pressure command value) and the clutch or brake (release element) released in accordance with the change of the gear position. The hydraulic pressure command value (release pressure command value) is set. Further, the shift ECU 21 changes any one or two of the first to fourth linear solenoid valves SL1 to SL4 corresponding to the engaged clutch or brake (engagement element) during the shift stage change or after the shift is completed. Set the hydraulic pressure command value (holding pressure command value) to For this reason, as shown in FIG. 1, the transmission ECU 21 has a hydraulic command value (applying to the engagement element) by cooperation of hardware such as CPU, ROM, and RAM and software such as a control program installed in the ROM. An engagement control module 211 for setting an engagement pressure command value and a holding pressure command value) and a release control module 212 for setting a hydraulic pressure command value (release pressure command value) for the release element are constructed as functional blocks. .

  Next, a hydraulic pressure command value (release pressure command value) to any one of the first to fourth linear solenoid valves SL1 to SL4 corresponding to the clutch or brake that is released when the shift stage is downshifted in the accelerator-on state. ) Will be described.

  FIG. 5 is a flowchart showing an example of a release control routine executed by the release control module 212 of the shift ECU 21 when downshifting the gear position in the accelerator-on state, and FIG. 6 is executed by the release control routine of FIG. The output torque Tout output to the output shaft 27 of the automatic transmission 25, the torque Te output from the engine 12, the rotational speed Ne of the engine 12, the input rotational speed Nin, the hydraulic pressure command value (Psl4 *), It is a time chart which illustrates a mode that accelerator opening Acc and target gear stage (gamma) tag change. Here, the release control routine of FIG. 5 will be described by taking as an example a case where the shift stage is downshifted from the second forward speed to the first forward speed while the accelerator pedal 91 is depressed by the driver. When downshifting from the second forward speed to the first forward speed, as can be seen from FIG. 3, only the release control routine is executed because the brake B1 is released while the engagement of the clutch C1 is maintained. . When another clutch or brake is engaged simultaneously with the release of any clutch or brake during downshifting, not shown for engaging the other clutch or brake in parallel with the release control routine. An engagement control routine is executed by the engagement control module 211 of the transmission ECU 21.

  The release control routine of FIG. 5 is performed when, for example, a predetermined delay time has elapsed since the release control module 212 of the shift ECU 21 determines that the shift stage should be downshifted according to the depression of the accelerator pedal 91 by the driver. Be started. When downshifting from the second forward speed to the first forward speed in the accelerator-on state, first, the release control module 212 performs a hydraulic command to the fourth linear solenoid valve SL4 corresponding to the brake B1 as the release element by the standby control. The value Psl4 * is set (step S10). In the standby control, for example, the disengagement side torque is obtained based on the estimated engine torque Test transmitted from the engine ECU 14, the torque ratio corresponding to the speed ratio of the fluid transmission device 23, and the torque sharing of the brake B1, and the hydraulic pressure to the brake B1 is determined. The hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 corresponding to the brake B1 is set so that becomes the target pressure (standby engagement pressure) corresponding to the release side torque.

  The speed ratio of the fluid transmission device 23 is calculated from the engine rotational speed Ne (input rotational speed of the fluid transmission device 23) transmitted from the engine ECU 14 and the input rotational speed Nin detected by the rotational speed sensor 98. Further, the torque ratio of the fluid transmission device 23 is set by deriving a value corresponding to the speed ratio from a predetermined map (not shown). Further, the hydraulic pressure command value Psl4 * is set by deriving a value corresponding to the release side torque from a predetermined map (not shown). The standby control in step S10 is, for example, from the start (time t0 in FIG. 6) to the input torque Tin of the automatic transmission 25 (torque applied to the input shaft 26 = estimated engine torque Test × torque ratio of the fluid transmission device 23). The process is executed until the standby time determined accordingly (until time t1 in FIG. 6).

  Next, the release control module 212 of the shift ECU 21 sets the hydraulic pressure command value Psl4 * by the initial shift control (step S20). In the initial shift control, for example, the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 corresponding to the brake B1 is set so that the hydraulic pressure to the brake B1 decreases with a relatively steep first gradient to the first target hydraulic pressure. Is set so that the hydraulic pressure to the brake B1 decreases at a second gradient that is gentler than the first gradient until the inertia phase, that is, the rotational change of the input shaft 26 (engine 12) is considered to have started. The hydraulic pressure command value Psl4 * is set. Note that the first target pressure is determined in consideration of the tie-up degree, drive feeling, and the like based on the release side torque obtained as described above. The initial speed change control in step S20 is executed until the input rotational acceleration dNin (change amount per unit time of the input rotational speed Nin) of the input shaft 26 reaches a predetermined value (until time t2 in FIG. 6).

When the input rotational acceleration dNin reaches a predetermined value, the release control module 212 of the transmission ECU 21 sets the hydraulic pressure command value Psl4 * by inertia phase control (step S30). In the inertia phase control, the hydraulic pressure command value Psl4 to the fourth linear solenoid valve SL4 corresponding to the brake B1 is set so that the hydraulic pressure to the brake B1 decreases at a predetermined relatively low gradient (may be a constant value). * Is set. The inertia phase control is executed until the shift progress degree Spr based on the rotation change amount of the input shaft 26 reaches a threshold value (until time t3 in FIG. 6). The speed change degree Spr is, for example, that the rotation speed (output rotation speed) of the output shaft 27 is “Nout”, the gear ratio of the current shift speed γ is “g _{i + 1} ”, and the gear ratio of the target shift speed γtag is “ g _i ″ is calculated from the following equation (1). The output rotation speed Nout can be obtained by multiplying the vehicle speed V by a predetermined conversion coefficient. Further, the threshold value to be compared with the shift progress degree Spr is set according to the vehicle speed V and a shift pattern (downshift pattern), for example.

Spr = 100 · (Nin-Nout · g _{i + 1} ) / (Nout · (g _i -g _{i + 1} )) (1)

  When the shift progress degree Spr reaches a predetermined value, the release control module 212 of the shift ECU 21 sets the hydraulic pressure command value Psl4 * by the rotation change rate control (step S40). In the rotation change rate control, the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 corresponding to the brake B1 is set by feedback control so that the input rotation acceleration dNin becomes the target rotation acceleration dNintag. The rotation change rate control is executed, for example, until the shift progress degree Spr reaches an end threshold value (for example, 90%) indicating substantial completion of the downshift. When an engagement element is present during downshifting in the accelerator-on state, in the rotation change rate control, the shift progress degree Spr reaches the end threshold value, and the hydraulic pressure to the engagement element is set by the engagement control routine. It is executed until it becomes larger than a predetermined target oil pressure in the inertia phase.

  Then, after the end of the rotation change rate control, the hydraulic pressure command value to the fourth linear solenoid valve SL4 corresponding to the brake B1 is set so that the hydraulic pressure to the brake B1 decreases to a value 0 with a predetermined relatively steep slope. Completion control for setting Psl4 * is executed (step S50). The completion control is executed until a predetermined time elapses from the start, and when the predetermined time elapses, the downshift from the second forward speed to the first forward speed in the accelerator-on state is completed.

  Next, the rotation rate control in step S40 in FIG. 5 will be described in detail with reference to FIG. FIG. 7 is a flowchart illustrating an example of a rotation change rate control routine that is repeatedly executed by the release control module 212 of the speed change ECU 21 at predetermined intervals when the hydraulic pressure command value Psl4 * is set by the rotation change rate control. Here, the rotation change rate control in step S40 will be described by taking as an example a case where the shift stage is downshifted from the second forward speed to the first forward speed while the accelerator pedal 91 is depressed by the driver.

  At the start of the routine of FIG. 7, the release control module 212 (a CPU (not shown)) has a vehicle speed V from the vehicle speed sensor 97, an input rotational speed Nin from the rotational speed sensor 98, an estimated engine torque Test from the engine ECU 14, an automatic transmission. Data required for control, such as 25 current gear stage γ, target gear stage γtag, and oil temperature Toil from oil temperature sensor 99 are input (step S400). Note that the current shift speed γ and the target shift speed γtag are stored in the RAM of the shift ECU 21 when the target shift speed γtag on the downshift side of the current shift speed γ is set from the above-described shift diagram. Become.

  After the data input process in step S400, the release control module 212 calculates the shift progress degree Spr according to the above equation (1) (step S402), and calculates the input rotational acceleration dNin and the target input rotational acceleration dNintag (step S404). ). The input rotational acceleration dNin is calculated by dividing the value obtained by subtracting the previous input value of the input rotational speed Nin from the input rotational speed Nin input in step S400 by the execution cycle of this routine. Further, the target input rotational acceleration dNintag is calculated from the following equation (2), for example, by setting a target shift time, which is a target time from the start to the end of inertia phase set in advance (start of completion control) as “ttag”. The

dNintag = Nout · (g _i -g _{i + 1} ) / tstag (2)

Next, the release control module 212 determines whether or not the flag F set to the value 0 at the start of this routine is the value 0 (step S406). During the execution, that is, by the feedback control, the remaining shift time tsr when setting the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 corresponding to the brake B1 by the feedback control is calculated (step S408). In the embodiment, the remaining shift time tsr is calculated as, for example, tsr = (Nin−Nout · g _{i + 1} ) / dNin. Further, the release control module 212 derives a determination time tref corresponding to the vehicle speed V, the current gear stage γ and the target gear stage γtag of the automatic transmission 25 input in step S400 from a predetermined determination time setting map (not shown). Set (step S410).

  The determination time setting map used in step S410 is a shift pattern (shift step: current shift stage γ and target shift stage) determined from the vehicle speed V (or the rotational speed Nout of the output shaft 27) and the current shift stage γ and the target shift stage γtag. This defines the relationship between the gear ratio difference from the stage γtag and the determination time tref. The determination time setting map is, for example, when the rotational change (rotational acceleration dNin) of the input rotational speed Nin is relatively small (for example, below a predetermined value) from the relationship between the vehicle speed V and the shift pattern (shift step), for example, When the vehicle speed V is low (for example, Nout is 2000 rpm or less) at the time of a low-speed downshift from the second speed to the first speed or from the third speed to the second speed, the judgment time is set to a relatively small positive value. Is set to a value of 0 (for example, 200 to 300 mSec), and is set to a value of 0 in other cases (when the rotational change of the input rotational speed Nin is relatively large). It should be noted that the determination time setting map may be created so that the determination time tref when the rotational change of the input rotation speed Nin is relatively small from the relationship between the vehicle speed V and the shift pattern is defined longer as the oil temperature Toil is lower. Good. Then, the release control module 212 determines whether or not the remaining shift time tsr calculated in step S408 is less than the determination time tref set in step S410 (step S412).

  If it is determined in step S412 that the remaining shift time tsr is equal to or longer than the determination time tref and the remaining shift time tsr is relatively long, the release control module 212 determines that the fourth linear solenoid corresponding to the brake B1 according to the following equation (3). A hydraulic pressure command value Psl4 * for the valve SL4 is set and transmitted to the hydraulic pressure control device 50 (step S420). Expression (3) is a relational expression of feedback control for setting the hydraulic pressure command value Psl4 * so that the input rotational acceleration dNin matches the target rotational acceleration dNintag. In the expression (3), “ “k1” is the gain of the proportional term, and “k2” of the third term on the right side is the gain of the integral term. Further, “j” in the expression (3) is one of the values 1, 2, 3, or 4 for indicating any one of the first to fourth linear solenoid valves SL1 to SL4 corresponding to the release element. At the time of downshift from the second forward speed to the first forward speed in the ON state, the value is 4 indicating the fourth linear solenoid valve SL4. When it is determined in step S412 that the remaining shift time tsr is equal to or greater than the determination time tref when this routine is executed for the first time after the end of the inertia phase control, the hydraulic pressure command value Psl (j ) * Last set value (previous Psl (j) *) is set immediately before the start of this routine.

  Psl (j) * = previous Psl (j) * + k1 ・ (dNintag * -dNin) + k2 ・ ∫ (dNintag * -dNin) dt (3)

  On the other hand, when it is determined in step S412 that the remaining shift time tsr is less than the determination time tref, the release control module 212 automatically multiplies the estimated engine torque Test input in step S400 by the torque ratio. An input torque Tin of the transmission 25 is calculated (step S414). Further, the release control module 212 derives a coefficient K corresponding to the target shift stage γtag (release element) input in step S400 from a predetermined coefficient setting map (not shown), and calculates the coefficient K in step S414. The value multiplied by the input torque Tin is set as the previous set value (previous Psl (j) *) of the hydraulic pressure command value Psl (j) * in the equation (3) (step S416). The coefficient setting map used in step S416 is determined in advance through experiments and analysis so as to define a coefficient K (for example, a value of about 70 to 80%) for each target gear stage γtag, and is stored in a ROM (not shown) of the transmission ECU 21. It is remembered. By performing the process of step S416, the previous set value of the hydraulic pressure command value Psl (j) * is changed to a value larger than the original value. The release control module 212 sets the flag F to 1 (step S418), and uses the value set in step S416 as the previous set value of the hydraulic pressure command value Psl (j) * in the equation (3). Then, the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 is set and transmitted to the hydraulic pressure control device 50 (step S420).

  After setting / transmitting the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 in step S420, the release control module 212 described above indicates that the shift progress Spr calculated in step S402 indicates that the downshift is substantially completed. Is determined (step S422), and if the shift progress degree Spr is less than the end threshold, the processing after step S400 is executed again. Further, when the flag F is set to the value 1 in step S408, since the negative determination is made in step S406 while the routine is repeatedly executed thereafter, the processing from the above steps S408 to S418 is performed. In step S420, the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 is set from the equation (3) using the previous setting value of the hydraulic pressure command value Psl (j) * as it is. If it is determined in step S422 that the shift progress degree Spr has reached the end threshold value, the release control module 212 sets the flag F to 0 (step S424) and ends this routine.

  As a result of the execution of the rotation change rate control routine as described above, if the remaining shift time tsr at the start of the rotation change rate control, that is, this routine is longer than the determination time tref, the hydraulic pressure command value Psl (j) * The hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 is set from the equation (3), which is a relational expression of feedback control that makes the input rotational acceleration dNin the target rotational acceleration dNintag using the previous set value of The In this case, the hydraulic pressure command value Psl4 * gradually increases from the start of the rotation change rate control and then gradually decreases from a certain timing (see the two-dot chain line in FIG. 6).

  On the other hand, if the remaining shift time tsr at the start of the rotation change rate control routine is less than the determination time tref, the previous set value of the hydraulic pressure command value Psl4 * is the original value immediately after the start of the rotation change rate control routine. The hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 is set from the equation (3) while being changed (raised) only once to a value corresponding to the large input torque Tin (steps S416 and S420). Further, for example, when the determination time tref is set to a positive value in step S410 during a downshift from the second speed to the first speed or from the third speed to the second speed at a low vehicle speed, the rotation change rate control routine is performed. Even when the remaining speed change time tsr becomes less than the determination time tref due to an increase in the rotational change (rotational acceleration dNin) of the input shaft 26 at a timing after a relatively short time from the start of the hydraulic pressure, The previous set value of the command value Psl4 * is changed (raised) only once to a value corresponding to the input torque Tin larger than the original value, and the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 from the equation (3) Is set (steps S416 and S420). Then, after the previous set value of the hydraulic pressure command value Psl4 * is raised from the original value as described above, the previous set value of the hydraulic pressure command value Psl (j) * is used as it is and the fourth linear from the equation (3). The hydraulic pressure command value Psl4 * for the solenoid valve SL4 is set (step S420). As a result, when the remaining shift time tsr when the rotation change rate control routine (feedback control) is executed is relatively short, the hydraulic pressure command value Psl4 * is the value of the rotation change rate control routine as shown by the solid line in FIG. For a while after the start, the oil pressure to the brake B1 is set to a relatively high value so as to increase, and then gradually decreases from a certain timing.

  Here, if the remaining shift time tsr when the hydraulic pressure command value Psl4 * is set by feedback control so that the input rotational acceleration dNin becomes the target rotational acceleration dNintag, the downshift is performed before the effect of the feedback control is obtained. In some cases, the effect of the feedback control is less likely to be obtained as the vehicle speed V is lower and the rotation change width of the input shaft 26 is smaller. Then, there is a time lag until the hydraulic pressure from the second linear solenoid valve SL4 responds to the hydraulic pressure command value Psl4 *, and when the effect of the feedback control cannot be obtained quickly, the brake B1 that is the release element is performed. As the hydraulic pressure increases, the rotational change of the input shaft 26 becomes steep, and the torque output to the output shaft 27 suddenly increases as shown by a two-dot chain line in FIG. There is a risk of generating.

  Based on this, in the automatic transmission 25 according to the embodiment, when the remaining shift time trs is less than the determination time tref, as described above, the hydraulic pressure command value Psl4 * to the fourth linear solenoid valve SL4 according to the equation (3). When the rotation change rate control routine is started (or after the start), the previous set value of the hydraulic pressure command value Psl4 * is changed (raised) only once. As a result, the hydraulic pressure applied to the brake B1, which is the release element, is raised compared to the case where the remaining shift time tsr is equal to or longer than the determination time tref. As a result, when downshifting from the second forward speed to the first forward speed in the accelerator-on state, the torque capacity of the brake B1 can be increased to cause the brake B1 to slip, as shown in FIG. In addition, it is possible to suppress a sudden increase in torque transmitted to the output shaft 27 while slowing the rotational change of the input shaft 26 (see the solid line in FIG. 7). Note that the release control routine and the rotation change rate control routine have been described so far, taking as an example the case where the shift stage is downshifted from the second forward speed to the first forward speed while the accelerator pedal 91 is depressed by the driver. As described above, both routines are also used when the downshift pattern other than the downshift from the second forward speed to the first forward speed is performed when the downshift of the shift stage is executed in the accelerator-on state. It goes without saying that the same applies.

  As described above, when the shift ECU 21 that is the control device of the automatic transmission 25 downshifts the shift stage in the accelerator-on state, after the rotational change of the input shaft 26 is started and the inertia phase control is executed. The hydraulic pressure command value Psl (j) * is set according to the relational expression (3) of the feedback control so that the rotational acceleration dNin of the input shaft 26 becomes the target rotational acceleration dNintag (step S420). Then, the shift ECU 21 determines that the remaining shift time tsr is equal to the determination time tref when the remaining shift time tsr at the start of setting the hydraulic pressure command value Psl (j) * by the rotation change rate control, that is, feedback control is less than the determination time tref. The hydraulic pressure command value Psl (j) * is set so that the hydraulic pressure to the release element is raised compared to the above case (steps S416 and S420). Thus, if the hydraulic pressure command value Psl (j) * is set so that the hydraulic pressure to the release element is increased when the remaining shift time tsr is less than the determination time tref, the torque capacity of the release element is increased. Thus, the release element can be caused to slip, whereby the rotational change of the input shaft 26 can be moderated, and the sudden increase in torque output to the output shaft 27 can be suppressed. Therefore, in the automatic transmission 25, it is possible to satisfactorily suppress the occurrence of shock when the shift stage is downshifted in the accelerator-on state. Note that “at the start of setting” of the hydraulic pressure command value Psl (j) * by the feedback control is a timing after the setting of the hydraulic pressure command value Psl (j) * by the feedback control is started, and the rotation change (rotation) of the input shaft 26 As described above, the remaining shift time tsr may be shortened by increasing the acceleration dNin).

  In the above embodiment, the feedback control in the rotation change rate control is performed at predetermined intervals according to the above equation (3) to the previous set value of the hydraulic pressure command value Psl (j) * and the rotational acceleration dNin of the input shaft 26 and the target rotation. The hydraulic pressure command value Psl (j) * is set by adding a feedback term based on the acceleration dNintag. Then, the shift ECU 21 increases the hydraulic pressure to the release element when the remaining shift time tsr at the start of setting the hydraulic pressure command value Psl (j) * by the rotation change rate control, that is, the feedback control is less than the determination time tref. As described above, the previous set value of the hydraulic pressure command value Psl (j) * is changed only once (step S416). As a result, it is possible to increase the hydraulic pressure to the release element more appropriately while leaving room for the effect of feedback control according to the above equation (3) after the previous set value of the hydraulic pressure command value Psl (j) * is changed. Become.

  Furthermore, in the above embodiment, the shift ECU 21 determines that the hydraulic pressure command value Psl (j) * is equal to the hydraulic pressure command value Psl (j) * when the remaining shift time tsr at the start of setting the hydraulic pressure command value Psl (j) * by the feedback control is less than the determination time tref. The previous set value is set to a value corresponding to the input torque Tin applied to the input shaft 26 (step S416). This makes it possible to make the increase in the torque capacity of the release element due to the change in the previous set value of the hydraulic pressure command value Psl (j) * more appropriate.

  In the above embodiment, the determination time tref is set to a value corresponding to the vehicle speed V (the rotational speed Nout of the output shaft 27) and the shift stage shift pattern (downshift pattern). As a result, the determination time tref can be set in consideration of the rotational change (rotational acceleration dNin) of the input shaft 26 according to the vehicle speed V (rotational speed Nout) and the shift pattern, so that the effect of the feedback control is obtained. It is possible to more appropriately determine whether or not

  Further, in the above embodiment, the setting of the hydraulic pressure command value Psl (j) * by the feedback control as described above is performed while the inertia phase control is executed after the rotation change of the input shaft 26 is started. This is started when the shift progress degree based on the rotation change amount exceeds the end threshold (predetermined value). Thereby, it is possible to more appropriately execute the rotation change rate control, that is, the setting of the hydraulic pressure command value Psl (j) * by the feedback control.

  Note that when the remaining shift time tsr at the start of setting the hydraulic pressure command value Psl (j) * by the rotation change rate control, that is, feedback control is less than the determination time tref, the effect of feedback control is obtained as described above. hard. Therefore, when the remaining shift time tsr is less than the determination time tref, the feedback control is stopped, and the feedforward control is performed so that the hydraulic pressure to the disengagement element is raised compared to the case where the remaining shift time tsr is equal to or longer than the determination time tref. May set the hydraulic pressure command value Psl (j) *.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above-described embodiment, the clutch C1 to C3 and the brakes B1 and B2 that are a plurality of friction engagement elements that are operated by the hydraulic pressure from the hydraulic control device 50 are provided, and the motive power applied from the engine 12 to the input shaft 26 is output. The shift ECU 21 that controls the automatic transmission 25 that can transmit to the shaft 27 corresponds to a “control device” and engages a release element that is at least one of the plurality of clutches C1 to C3 and the brakes B1 and B2. The release control module 212 executes the release control routine of FIG. 5 and the rotation change rate control routine of FIG. 7 while generating the hydraulic pressure to the release element when the shift stage is downshifted from the state to the release state. Corresponds to “release control means”. However, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the invention described in the column of means for solving the problem by the embodiment. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the examples are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is It should be done based on the description.

  As mentioned above, although the embodiment of the present invention has been described using examples, the present invention is not limited to the above-described examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the transmission manufacturing industry.

  DESCRIPTION OF SYMBOLS 10 Automotive, 12 Engine, 14 Engine electronic control unit (engine ECU), 16 Brake electronic control unit (brake ECU), 20 Power transmission device, 21 Transmission electronic control unit (transmission ECU), 22 Transmission case, 23 Fluid Transmission device, 23a pump impeller, 23b turbine runner, 23c lock-up clutch, 24 oil pump, 25 automatic transmission, 26 input shaft, 27 output shaft, 28 gear mechanism, 29 differential mechanism, 30 single pinion planetary gear mechanism, 31, 36a, 36b Sun gear, 32, 37 ring gear, 33 pinion gear, 34, 39 carrier, 35 Ravigneaux planetary gear mechanism, 38a short pinion gear, 38b long pinion gear, 50 hydraulic control device, 51 primer Regulator valve, 52 Manual valve, 53 Apply control valve, 91 Accelerator pedal, 92 Accelerator pedal position sensor, 93 Brake pedal, 94 Master cylinder pressure sensor, 95 Shift lever, 96 Shift range sensor, 97 Vehicle speed sensor, 98 Speed sensor, 99 oil temperature sensor, 211 engagement control module, 212 release control module, B1, B2 brake, C1, C2, C3 clutch, F1 one-way clutch, SL1 first linear solenoid valve, SL2 second linear solenoid valve, SL3 third linear Solenoid valve, SL4 4th linear solenoid valve, SLT linear solenoid valve.

Claims (6)

In a control device for a transmission having a plurality of friction engagement elements that are operated by hydraulic pressure from a hydraulic control device and capable of transmitting power applied from a prime mover to an input shaft to an output shaft,
The hydraulic pressure that generates hydraulic pressure to the release element when the release element, which is at least one of the plurality of friction engagement elements, is switched from the engagement state to the release state to downshift the shift stage. A release control means for setting a hydraulic pressure command value to the control device;
The release control means performs the hydraulic control by feedback control so that the rotational acceleration of the input shaft becomes the target rotational acceleration after the rotational change of the input shaft is started when the shift stage is downshifted in an accelerator-on state. The command value is set, and when the remaining shift time at the start of setting the hydraulic pressure command value by the feedback control is less than the determination time, the release element is compared with the case where the remaining shift time is equal to or longer than the determination time. The transmission control apparatus is characterized in that the hydraulic pressure command value is set so that the hydraulic pressure of the transmission is raised. The transmission control device according to claim 1,
In the feedback control, the hydraulic pressure command value is set by adding a feedback term based on the rotational acceleration of the input shaft and the target rotational acceleration to the previous setting value of the hydraulic pressure command value every predetermined time. ,
When the remaining shift time at the start of setting of the hydraulic pressure command value by the feedback control is less than the determination time, the release control means sets the previous set value once so that the hydraulic pressure to the release element is raised. A transmission control device characterized by only changing. The transmission control device according to claim 2,
When the remaining shift time at the start of setting of the hydraulic pressure command value by the feedback control is less than the determination time, the release control means sets the previous set value to a value according to the input torque applied to the input shaft. A control apparatus for a transmission. The transmission control device according to any one of claims 1 to 3,
The transmission control device according to claim 1, wherein the determination time is set to a value corresponding to a rotation speed of the output shaft and a shift pattern of the shift stage. The transmission control device according to claim 1,
The setting of the hydraulic pressure command value by the feedback control is started when the rotation change of the input shaft is started and the shift progress degree based on the rotation change amount of the input shaft exceeds a predetermined value. A transmission control device. In a control method for a transmission that has a plurality of friction engagement elements that are operated by hydraulic pressure from a hydraulic control device and that can transmit power applied from a prime mover to an input shaft to an output shaft.
The hydraulic pressure that generates hydraulic pressure to the release element when the release element, which is at least one of the plurality of friction engagement elements, is switched from the engagement state to the release state to downshift the shift stage. Including a release pressure setting step for setting a hydraulic pressure command value to the control device,
The release pressure setting step is performed by feedback control so that the rotational acceleration of the input shaft becomes the target rotational acceleration after the rotational change of the input shaft is started when the shift stage is downshifted in an accelerator-on state. Setting the hydraulic pressure command value and releasing the release time when the remaining shift time at the start of setting the hydraulic pressure command value by the feedback control is less than the determination time compared to when the remaining shift time is greater than or equal to the determination time A transmission control method for setting the hydraulic pressure command value so that the hydraulic pressure to the element is raised.

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