JP3723103B2 - Shift control device for automatic transmission for vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a shift control device for a vehicular automatic transmission, and more particularly to a technique for performing a coast down shift while maintaining a vehicle in a minute driving state.
[0002]
[Prior art]
Proposed a downshift control device for an automatic transmission for a vehicle that maintains the vehicle in a weak engine brake state when downshifting is performed during coasting such as coasting traveling or deceleration traveling of a vehicle in which the accelerator pedal is not operated. Has been. For example, the apparatus described in JP-A-11-287317 is that. According to this, since a predetermined engine braking force is always applied to the vehicle during clutch-to-clutch downshifting, excessive engine braking force and shift shock are applied even when downshifting to a low gear. There is an advantage that it is not generated.
[0003]
[Problems to be solved by the invention]
By the way, in clutch-to-clutch downshift in an automatic transmission for a vehicle, the input of the automatic transmission is performed so that the release-side frictional engagement device is released and the engagement-side hydraulic frictional engagement device is engaged at the same time. Blowing of the rotary shaft and temporary drop (tie-up) of the output shaft torque are likely to occur, and the engagement pressure at the time of releasing the release-side frictional engagement device and the engagement of the engagement-side hydraulic frictional engagement device Since expensive equipment with very high control accuracy for engagement pressure is required, general devices that can be used for general vehicles are sufficiently robust against disturbances such as vehicle braking (control robustness). May not be obtained.
[0004]
The present invention has been made against the background of the above circumstances, and the object of the present invention is to perform vehicle braking, etc. without a high-precision control device in clutch-to-clutch downshift control during coasting. It is an object of the present invention to provide a shift control device for a vehicle automatic transmission that has sufficient robustness against external disturbances.
[0005]
[To solve the problemFirstmeans】
  To achieve this goalFirstThe gist of the invention is that in a vehicular automatic transmission in which torque transmitted from an engine is input via a fluid transmission, the release-side hydraulic friction engagement device is released and the engagement-side hydraulic friction engagement is achieved. A shift control device for a vehicle automatic transmission of a type that executes a clutch-to-clutch down shift achieved by engagement of a combined device during coasting, comprising: (a) an input / output rotational speed difference of the fluid transmission device; An input / output rotational speed difference detecting means for detecting (b) a clutch-to-clutch downshift executed during coasting, based on the input / output rotational speed difference detected by the input / output rotational speed difference detecting means; A minute driving state control means for controlling the rotation speed of the engine to increase, thereby bringing the vehicle into a minute driving state;, (c) Synchronization determination means for determining whether or not the rotation of the engagement-side hydraulic friction engagement device involved in the clutch-to-clutch downshift is synchronized; (d) When the synchronization determination means determines that the rotation of the engagement-side hydraulic friction engagement device is synchronized, the engagement pressure of the engagement-side hydraulic friction engagement device is quickly increased from the previous standby pressure. Engagement side engagement pressure control meansIs to include.
[0006]
[Effect of the first invention]
  In this way, when the clutch-to-clutch downshift is executed by coasting by the minute drive state control means, the engine speed is determined based on the input / output rotational speed difference detected by the input / output rotational speed difference detection means. Since the vehicle is maintained in the minute drive state by increasing the amount of the engine, if the clutch-to-clutch downshift control during coasting is executed in such a minute drive state, the torque fluctuation is small, and therefore the high hydraulic pressure Control accuracy is obtained, and sufficient robustness against disturbances such as vehicle braking can be obtained without providing expensive equipment with high control accuracy.In addition, when it is determined that the rotation of the engagement-side hydraulic friction engagement device is synchronized, the engagement pressure of the engagement-side hydraulic friction engagement device is quickly increased from the standby pressure so far. The shift can be completed promptly without causing a shift shock.
[0007]
[Second means for solving the problem]
  Further, the gist of the second invention for achieving the object is to provide a release-side hydraulic friction engagement device in an automatic transmission for a vehicle in which torque transmitted from an engine is input via a fluid transmission device. A shift control device for an automatic transmission for a vehicle of a type that executes a clutch-to-clutch downshift achieved by releasing the clutch and engaging the engagement-side hydraulic friction engagement device during coasting, (a) An input / output rotational speed difference detecting means for detecting an input / output rotational speed difference of the fluid transmission, and (b) a clutch-to-clutch downshift executed during the coasting is detected by the input / output rotational speed difference detecting means. Minute drive state control means for making the vehicle in a minute drive state by increasing the rotation speed of the engine based on the input / output rotation speed difference, and (c) a sudden braking state of the vehicle. A sudden braking state determining means for constant, if the sudden braking state of the vehicle is determined by the (d) the rapid braking state determining means,Previous clutch-to-clutchFrom coast down shift outputAlready implementedAnd minute drive control stopping means for immediately stopping the engine speed increase control for setting the minute drive state to be continued.
  According to the second aspect of the invention thus configured, the input / output rotational speed difference detected by the input / output rotational speed difference detecting means when the clutch-to-clutch downshift is executed by the minute driving state control means during coasting. Since the vehicle is maintained in the minute drive state by performing the increase control of the engine rotation speed on the basis of the torque, the clutch-to-clutch downshift control during the coasting is executed in such a minute drive state. Since there is little fluctuation, high hydraulic control accuracy can be obtained, and sufficient robustness against disturbances such as vehicle braking can be obtained without providing expensive equipment with high control accuracy. Also, if it is determined that the vehicle is suddenly braked,Clutch-to-clutchFrom coast down shift outputAlready implementedSince the engine speed increase control, that is, the minute drive control for making the minute drive state continued is immediately stopped, there is an advantage that the influence on the subsequent clutch-to-clutch coast downshift control is eliminated.
[0010]
Other aspects of the invention
  Here, it is preferable that the minute driving state control means decreases the increase amount of the engine rotation speed that is increased in order to bring the vehicle into the minute driving state as the vehicle speed decreases. In this way, if the vehicle speed decreases during braking, the increase amount of the engine rotation speed that is controlled to increase in order to achieve a minute drive state is also reduced accordingly, so that the engine rotation speed and the fluid transmission device are switched on. There is an advantage that the minute driving state is maintained even during vehicle braking in which the output rotational speed difference tends to increase. For this reason, if the increase amount of the engine rotation speed is not decreased, it is difficult to engage the engagement side hydraulic friction engagement device at the end by the hydraulic control of the clutch-to-clutch shift. According to this, the engagement side hydraulic friction engagement device can be easily engaged at the end of shifting.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0012]
In the vehicle of FIG. 1, the output of the engine 10 is transmitted to driving wheels (front wheels) (not shown) via a torque converter 12 as a fluid transmission device, an automatic transmission 14 for driving FFs, and a differential gear device 16. It has become. The torque converter 12 includes a pump impeller 20 connected to the crankshaft 18 of the engine 10, a turbine impeller 24 connected to the input shaft 22 of the automatic transmission 14, and a non-rotating member via a one-way clutch 26. A stator impeller 30 fixed to the housing 28 and a lockup clutch 32 connected to the input shaft 22 via a damper (not shown).
[0013]
The automatic transmission 14 is coaxially disposed on the input shaft 22 and a carrier and a ring gear are connected to each other to thereby form a so-called CR-CR coupled planetary gear mechanism. A first planetary gear unit 40 and a second planetary gear unit 42; a set of third planetary gear units 46 arranged coaxially on a counter shaft 44 parallel to the input shaft 22; and a shaft end of the counter shaft 44 An output gear 48 that is fixed and meshes with the differential gear device 16 is provided. The components of the planetary gear units 40, 42, 46, that is, the sun gear, the ring gear, and the carrier that rotatably supports the planet gears meshing with them are selectively connected to each other by four clutches C0, C1, C2, and C3. Alternatively, the three brakes B1, B2, and B3 are selectively connected to the housing 28 that is a non-rotating member. The two one-way clutches F1 and F2 are engaged with each other or with the housing 28 depending on the rotation direction. Since the differential gear device 16 is configured symmetrically with respect to the axis (axle), the lower side is not shown.
[0014]
The first planetary gear unit 40, the second planetary gear unit 42, the clutches C0, C1, C2, the brakes B1, B2, and the one-way clutch F1 disposed on the input shaft 22 are used to move forward four steps and reverse one step. The main transmission unit MG is configured, and the sub-transmission unit, that is, the underdrive unit U / D is configured by a set of planetary gear unit 46, clutch C3, brake B3, and one-way clutch F2 disposed on the counter shaft 44. ing. In the main transmission unit MG, the input shaft 22 is connected to the carrier K2 of the second planetary gear unit 42, the sun gear S1 of the first planetary gear unit 40, and the sun gear S2 of the second planetary gear unit 42 via the clutches C0, C1, and C2. Each is connected. The ring gear R1 of the first planetary gear unit 40 and the carrier K2 of the second planetary gear unit 42 are connected, and the ring gear R2 of the second planetary gear unit 42 and the carrier K1 of the first planetary gear unit 40 are connected to each other. The sun gear S2 of the second planetary gear unit 42 is connected to the housing 28 that is a non-rotating member via a brake B1, and the ring gear R1 of the first planetary gear unit 40 is a housing 28 that is a non-rotating member via a brake B2. It is connected to. A one-way clutch F1 is provided between the carrier K2 of the second planetary gear unit 42 and the housing 28 which is a non-rotating member. The first counter gear G1 fixed to the carrier K1 of the first planetary gear device 40 and the second counter gear G2 fixed to the ring gear R3 of the third planetary gear device 46 are meshed with each other. In the underdrive unit U / D, the carrier K3 and the sun gear S3 of the third planetary gear unit 46 are connected to each other via the clutch C3, and between the sun gear S3 and the housing 28 that is a non-rotating member, A brake B3 and a one-way clutch F2 are provided in parallel.
[0015]
The clutches C0, C1, C2, and C3 and the brakes B1, B2, and B3 are hydraulic friction engagement devices that are controlled by a hydraulic actuator such as a multi-plate clutch or a band brake. By operating these hydraulic actuators, the clutch C and the brake B are selectively engaged, so that one of the five forward speeds is established as shown in FIG. In FIG. 2, “◯” means engagement, “Δ” means engagement only during driving, and “X” means release. In FIG. 2, for example, a 4 → 5 shift or a 5 → 4 shift between the 4th speed gear stage and the 5th speed gear stage is achieved by engagement or release of the clutch C3. The 1 → 2 shift or 2 → 1 shift between the gear stage is achieved by engaging or releasing the brake B1. However, the 2 → 3 shift or 3 → 2 shift between the second gear and the third gear is performed by releasing the brake B1 and engaging the clutch C0, or releasing the clutch C0 and engaging the brake B1. Is a so-called clutch-to-clutch shift achieved by releasing one of the gears and engaging the other at the same time, and a 3 → 4 shift or a 4 → 3 between the third gear and the fourth gear. The shift is also a so-called clutch-to-clutch shift achieved by releasing the clutch C1 and engaging the brake B1, or releasing the brake B1 and engaging the clutch C1.
[0016]
In FIG. 3, a throttle valve 52 driven by a throttle actuator 50 is provided in the intake pipe of the engine 10 of the vehicle, and an engine rotational speed N during idling is provided in parallel with the throttle valve 52._EAnd an ISCV valve 54 for controlling. The opening degree θ of the throttle valve 52 is controlled so as to increase in accordance with the operation amount of the accelerator pedal 56. Further, the rotational speed N of the engine 10_EThe engine rotation speed sensor 58 for detecting the intake air amount sensor 60 for detecting the intake air amount Q of the engine 10 and the temperature T of the intake air._AThe intake air temperature sensor 62 for detecting the throttle valve, the throttle sensor 64 for detecting the opening degree θ of the throttle valve 52, and the rotational speed (counter rotational speed) N of the second counter gear G2._CCounter rotational speed sensor 65 for detecting vehicle speed, vehicle speed sensor 66 for detecting vehicle speed V, and coolant temperature T of engine 10_WCoolant temperature sensor 68 for detecting the oil pressure, hydraulic oil temperature T of the automatic transmission 14_OILThe hydraulic oil temperature sensor 69 detects the operation of the brake, the brake switch 70 detects the operation of the brake, the operation position sensor 74 detects the operation position of the shift lever 72, the rotational speed of the turbine wheel 24, that is, the turbine rotational speed N_T(= Rotational speed N of the input shaft 22_IN) Is detected, and the engine rotation speed N is determined from these sensors._E, Intake air amount Q, intake air temperature T_A, Throttle valve opening θ, counter rotational speed N_C, Vehicle speed V, engine coolant temperature T_W, Hydraulic oil temperature T_OIL, Brake operating state BK, operation position Psh of shift lever 72, turbine rotational speed N_TAnd the like are supplied to the engine electronic control device 76 and the shift electronic control device 78.
[0017]
The engine electronic control device 76 is a so-called microcomputer having a CPU, a RAM, a ROM, and an input / output interface, and the CPU processes an input signal in accordance with a program stored in the ROM in advance using a temporary storage function of the RAM. Then, various engine controls are executed. For example, the fuel injection valve 80 is controlled for controlling the fuel injection amount, the igniter 82 is controlled for controlling the ignition timing, and the opening degree θ of the throttle valve 52 is determined from the prestored relationship shown in FIG. Based on the operation amount of the accelerator pedal 56, it controls so that it may be increased according to the increase. Idle speed control or engine speed N_EThe ISC valve 54 is controlled to lift a predetermined amount.
[0018]
The shift electronic control unit 78 is also a microcomputer similar to the above, and the CPU processes the input signal in accordance with a program stored in the ROM 79 in advance while using the temporary storage function of the RAM, and each electromagnetic control circuit 84 is controlled. Drives a valve or linear solenoid valve. That is, for example, the gear position of the automatic transmission 14 and the shift determination of the lock-up clutch 24 are determined based on the actual throttle valve opening θ and the vehicle speed V from the pre-stored shift diagram shown in FIG. The solenoid valve S4, solenoid valve SR, linear solenoid valve SLT, SL1, SL2, SL3, etc. are driven so that the gear stage and the engaged state can be obtained.
[0019]
FIG. 6 is a diagram simply showing the main part of the hydraulic control circuit 84. In FIG. 6, the electromagnetic valve SR applies its output pressure to the 2-3 shift valve 100 via a relatively long oil passage 98 in accordance with a command from the shift electronic control device 78 to cause the 2-3 shift valve 100 to operate. Switch alternatively between 1st to 2nd speed and 3rd to 5th speed. The electromagnetic valve S4 causes its output pressure to act on the 4-5 shift valve 102 via its 2-3 shift valve 100 switched to the 3rd to 5th gears according to the command from the shift electronic control unit 78, The 4-5 shift valve 102 is selectively switched between the 1st to 4th speed sides and the 5th speed side. That is, when the 4-5 shift valve 102 is switched to the first speed to the fourth speed side, the forward range pressure, that is, the D range pressure P_DIs supplied to the brake B3, and when the 4-5 shift valve 102 is switched to the fifth speed side, the D range pressure P_DIs supplied to the clutch C3 and the accumulator AC3. The linear solenoid valve SLT supplies its output pressure to the back pressure control valve 104 in accordance with a command from the shift electronic control device 78, generates a back pressure corresponding to the output pressure, and supplies it to the back pressure port of the accumulator AC3. Let
[0020]
The linear solenoid valve SL1 supplies its output pressure to the B1 control valve 106 in accordance with a command from the shift electronic control unit 78, and an engagement pressure P corresponding to the output pressure._B1Is generated and regulated to be supplied to the brake B1 and its accumulator AB1. The linear solenoid valve SL2 supplies its output pressure to the C0 control valve 108 via the 2-3 shift valve 100 that can be switched by the electromagnetic valve SR in accordance with a command from the shift electronic control unit 78, and is associated with the output pressure. Combined pressure P_C0Is generated and regulated to be supplied to the clutch C0 and its accumulator AC0. The linear solenoid valve SL3 supplies its output pressure to the C1 control valve 110 in accordance with a command from the shift electronic control device 78, and an engagement pressure P corresponding to the output pressure._C1Is generated and regulated to be supplied to the clutch C1 and its accumulator AC1. Engaging pressure P of the clutch C0_C0And the engagement pressure P of the clutch C1_C1Is the engagement pressure P_C1Is supplied to the clutch C0 and the clutch C1 via the clutch pressure supply control valve 112 switched by the above.
[0021]
FIG. 7 is a functional block diagram for explaining a main part of the control function of the shift electronic control unit 78. The shift control means 120 makes a shift determination based on the actual vehicle state, for example, the vehicle speed V and the throttle opening θ or the accelerator pedal operation amount from the relationship stored in advance as shown in FIG. 5, for example, and the determined shift is executed. As described above, a shift output signal is output from the shift output means 122. For example, when the point indicating the vehicle state in the shift diagram of FIG. 5 crosses the 5 → 4 down shift to the low speed side, it is determined that the 5 → 4 down shift is performed, and the 4-5 shift valve 102 is moved by the electromagnetic valve S4. The clutch C3 is released by switching to the fourth speed side. Further, in the shift diagram of FIG. 5, when the point indicating the vehicle state crosses the 4 → 3 down shift to the low speed side, it is determined that the 4 → 3 down shift, and in order to realize the 4 → 3 down shift Engagement pressure P for releasing brake B1 and engaging clutch C1_B1And P_C1The output (drive) signal for generating is output to the linear solenoid valves SL1 and SL3. The output signal has a duty ratio changed as shown in FIG. 14, for example. Since the linear solenoid valves SL1 and SL3 are normally open type, when the duty ratio of the signal supplied thereto is 100%, the output pressure P_B1And P_C1Each has a characteristic of zero.
[0022]
The shift control means 120 includes an engagement pressure P of the brake B1, which is a disengagement hydraulic friction engagement device, in order to suitably realize the 4 → 3 downshift during coasting._B1The disengagement-side engagement pressure control means 122 for controlling the engagement and the engagement pressure P of the clutch C1 which is an engagement-side hydraulic friction engagement device_C1The engagement-side engagement pressure control means 124 that controls the rotation of the clutch C1 that is the completion of the 4 → 3 down-shift is synchronized with, for example, the turbine rotation speed N._TAnd counter rotation speed N_CAnd synchronization determination means 126 for determining on the basis of the fact that they match. The disengagement-side engagement pressure control means 122 and the engagement-side engagement pressure control means 124 are configured to apply the engagement pressure P of the brake B1 from the start of the shift to the end of the shift according to a preset program or feedback control formula._B1And the engagement pressure P of the clutch C1_C1Are changed sequentially. For example, the disengagement-side engagement pressure control means 122 may calculate the input / output rotational speed difference N of the torque converter 12 from a previously stored relationship as shown in FIG._SLIP(= N_E-N_T) And counter rotation speed N_CRelease initial pressure P based on_B1IAnd the initial release pressure P_B1IDrive signal DP for maintaining_B1IIs supplied to the linear solenoid valve SL1. Further, the engagement side engagement pressure control means 124 also has an input / output rotational speed difference N as shown in FIG._SLIPAs the value increases, the counter rotation speed N_CFrom the relationship stored in advance so that the initial hydraulic pressure increases as the engine speed decreases, the input / output rotational speed difference N of the torque converter 12 increases._SLIP(= N_E-N_T) And counter rotation speed N_CBased on the initial engagement pressure P_C1IAnd the initial release pressure P_C1IDrive signal D for maintaining_C1IIs supplied to the linear solenoid valve SL3. In such a clutch-to-clutch 4 → 3 downshift, the engagement-side clutch C1 is gradually engaged while the release-side brake B1 is slid while the tie-up and the input shaft rotation speed are kept below a predetermined amount. So that the brake B1 and the clutch C1 are released from the initial pressure P._C1IAnd initial engagement pressure P_C1IRespectively maintained. The engagement-side engagement pressure control means 124, when the synchronization determination means 126 determines the rotation synchronization of the clutch C1 that is the completion of the 4 → 3 downshift, the drive signal D supplied to the linear solenoid valve SL3._C1By setting the duty ratio of the clutch to 0%, the engagement pressure P of the clutch C1_C1Is increased to a predetermined value, for example, the maximum value.
[0023]
The input shaft rotational speed state detection means 128 is used for coasting such as coasting traveling of the vehicle, and the input / output rotational speed difference N of the torque converter 12 that is a fluid transmission device._SLIP(= N_E-N_T) Engine speed N_EAnd turbine rotation speed N_TIt detects by calculating based on. The inertia phase determining means 130 determines the start point of the inertia phase in the 4 → 3 downshift or the vicinity thereof, for example, the engine speed N_EOr turbine rotation speed N_TThis is determined by detecting the rising start point or by detecting that the elapsed time from the 4 → 3 downshift output has passed a preset time. The vehicle speed detecting means 132 detects the counter rotational speed N at the vehicle speed V or the rotational speed of other members that change in relation thereto, for example, at the fourth speed or lower._CIs detected.
[0024]
After the vehicle coasting 4 → 3 downshift output, the minute driving state control means 134, for example, the input / output rotational speed difference N in a predetermined section up to that point from the previously stored relationship of FIG._SLIPAverage value N_SLIPAVBased on the engine rotational speed lifting amount ΔN_E(R.p.m) is determined, and its lift amount ΔN_EIs output to the ISC valve 54 to obtain the vehicle speed of the engine N_EIs the turbine speed N_TThe turbine rotational speed N is increased by a relatively small predetermined value._TIs a minute driving state slightly exceeding. The above relationship is the average value N_SLIPAVThe larger the value, the higher the engine speed lift ΔN_ETherefore, the input / output rotational speed difference N in coasting is controlled by the above control._SLIPIs maintained at a relatively small, substantially constant value. The minute drive state control means 134 is after the output of the 4 → 3 down shift during coasting and in the 4 → 3 down shift, the rotational speed N of the turbine impeller 24 is rotated._TAfter the inertia phase starting point, which is the starting point of change (rise) of the vehicle, minute driving control is performed to bring the vehicle into a minute driving state. In addition, the minute drive state control means 134 can detect the actual vehicle speed V, that is, the counter rotational speed N from the relationship stored in advance as shown in FIG._CEngine speed increase amount ΔN based on the decrease rate of_EDecrease rate of engine speed is increased, and engine speed increase amount ΔN according to the decrease rate_EDecrease in real time. Accordingly, during braking of the vehicle within the 4 → 3 coast down shift period, the engine rotational speed lifting amount ΔN according to this decrease rate._EAs a result, the input / output rotational speed difference N is reduced._SLIPIs continuously reduced.
[0025]
The sudden braking state determination means 136 determines whether or not a sudden braking state of the vehicle has occurred, for example, if the vehicle speed ratio or deceleration calculated from the vehicle speed V, the brake pedal operating force, the braking hydraulic pressure, etc. have exceeded a criterion value. Judgment based on. When the sudden braking state determining unit 136 determines that the vehicle sudden braking state has occurred, the minute drive control stopping unit 138 determines that the engine rotational speed lifting amount ΔN_EBy setting the value to zero, the minute drive control by the previous minute drive state control means 140 that has already been carried out after, for example, the output of 5 → 4 coast down shift before that time is immediately stopped. The minute driving control by the previous minute driving state control unit 140 is the same as the minute driving control by the minute driving state control unit 134.
[0026]
FIGS. 11, 12, and 13 are flowcharts for explaining a main part of the control operation of the shift electronic control device 78. FIG. 11 shows a minute drive for setting the vehicle in a minute drive state during the coast down period. FIG. 12 shows a disengagement side engagement pressure control routine in the clutch-to-clutch coast downshift, and FIG. 13 shows an engagement side engagement pressure control routine in the clutch-to-clutch coastdown shift.
[0027]
The minute drive control routine of FIG. 11 is executed after the front downshift during coasting, for example, after the 5 → 4 downshift output. In FIG. 11, in SA1 corresponding to the sudden braking determination means 136, it is determined whether or not sudden braking of the vehicle has occurred. If the determination in SA1 is affirmative, the minute drive control that has been executed after the previous shift, that is, after the 5 → 4 downshift output in SA2 corresponding to the minute drive stop means 138 is stopped. T in FIG.₂The time point indicates this state. However, if the determination at SA1 is negative, it is determined at SA3 corresponding to the shift control means 120 whether or not the clutch-to-clutch downshift, that is, the 4 → 3 downshift, during coasting. If the determination at SA3 is negative, this routine is terminated. If the determination is affirmative, at SA4, for example, the input / output rotational speed difference N in a predetermined section up to that point from the previously stored relationship of FIG._SLIPAverage value N_SLIPAVBased on the engine rotational speed lifting amount ΔN_E(R.p.m) is determined. Next, at SA5, the counter rotational speed N decreased during braking or the like._CIn order to reduce the minute driving state in accordance with the decrease rate of the actual vehicle speed V, that is, the counter rotational speed N from the previously stored relationship shown in FIG._CEngine speed increase amount ΔN based on the decrease rate of_EDecrease rate of engine speed is increased, and engine speed increase amount ΔN according to the decrease rate_EDecrease in real time. Input / output rotational speed difference N_SLIPIs continuously reduced.
[0028]
Next, at SA6, the engine speed N_EIs the turbine rotation speed (N_TIt is determined whether it is greater than + α). α is N_SLIPIs a margin value for determining that is stably positive. Engine speed N_EAnd turbine rotation speed N_TThis is because the control method is switched in accordance with the size of. T in FIG._ThreeThe time point indicates this state. If the determination of SA6 is negative, the engine speed N_EIs the turbine speed N_TThe engine speed changed to SA5 in SA7 so as to cope with a special state below the engine, for example, when the engine friction at the time of starting the engine is large or the engine load becomes large due to the air conditioner driving. Lifting amount ΔN_EThe drive signal is determined so that the ISC valve 54 is slowly driven at a predetermined speed until reaching the value. However, if the determination at SA6 is affirmative, the engine speed N_EIs the turbine speed N_TTherefore, SA8 or less is executed.
[0029]
As described above, the engine speed lifting amount ΔN_EIs determined, in SA8 corresponding to the inertia phase determination means 130, the start of the inertia phase following the torque phase of the 4 → 3 downshift is the turbine rotational speed N_TThis is determined by detecting the start of rotation change (increase). While the determination of SA8 is denied, the process waits, but when the determination of SA8 is affirmed, in SA9, the determined engine rotational speed lifting amount ΔN_EIs obtained to the ISC valve 54, and the engine speed N_EIs the turbine speed N_TIs maintained in a minute driving state slightly exceeding T in FIG._FourThe time point indicates the time point when the minute drive state is started after the 4 → 3 downshift output by outputting the ISC request amount to the ISC valve 54. T in FIG._FourAfter that time, the counter speed N_CAre sequentially decreased, and accordingly, the engine speed lifting amount ΔN_EIs reduced and the input / output rotational speed difference N is within the 4 → 3 downshift period._SLIPIs continuously reduced.
[0030]
Next, for the clutch-to-clutch 4 → 3 downshift during coasting, t in FIG._ThreeThe hydraulic control operation executed after the time will be described with reference to FIGS. FIG. 12 shows the engagement pressure P of the brake B1, which is a release side hydraulic friction engagement device of 4 → 3 downshift._B1FIG. 13 shows an engagement pressure P of the clutch C1, which is a 4 → 3 downshift engagement side hydraulic friction engagement device._C1The control operation is shown. In this embodiment, t in FIG.₂Counter rotation speed N after the time_CAs shown in FIG. 4, the 4 → 3 shift is executed during braking.
[0031]
In FIG. 12, in SB1, it is determined whether or not a clutch-to-clutch 4 → 3 downshift is determined. If the determination at SB1 is negative, this routine is terminated. If the determination is affirmative, the duty ratio of the drive signal for the linear solenoid valve SL1 is temporarily set at 100% at SB2, so that the first drain That is, the initial rapid discharge operation of the hydraulic oil from the brake B1 is performed. In the subsequent SB3, for example, the actual input / output rotational speed difference N is determined from the relationship stored in advance as shown in FIG._SLIPAnd counter rotation speed N_CBased on the initial pressure P_B1IIs determined and the initial pressure P is applied to the brake B1._B1IDrive signal D for holding for a predetermined period of time_SL1IIs retained. This initial pressure P_B1IMay be corrected by learning correction or the like so that the 4 → 3 downshift is smooth. In SB4, the duty ratio of the drive signal of the linear solenoid valve SL1 is gradually increased by, for example, rotational speed feedback so that the brake B1 is gently drained.
[0032]
In FIG. 13, at SC1, it is determined whether or not a clutch-to-clutch 4 → 3 downshift is determined. If the determination of SC1 is negative, this routine is terminated. If the determination is positive, the duty ratio of the drive signal of the linear solenoid valve SL3 is temporarily reduced after the first drain of the brake B1 in SC2. As a result, the first fill to the linear solenoid valve SL3, that is, the quick supply of hydraulic oil to the clutch C1 is performed in order to pack the piston of the clutch C1. Next, at SC3, for example, the actual input / output rotational speed difference N is determined from the relationship stored in advance as shown in FIG._SLIPAnd counter rotation speed N_CBased on the initial pressure P_C1IIs determined and the initial pressure P is applied to the brake B1._C1IThe duty ratio D of the drive signal of the linear solenoid valve SL3 is maintained for a predetermined period of time._SL3IIs maintained. As a result, both the brake B1 on the release side and the clutch C1 on the engagement side are brought into the slip state, and during this time, the engagement torque of the brake B1 is decreased and at the same time the engagement torque of the clutch C1 is increased. This initial pressure P_C1IIn some cases, correction is performed by learning correction or the like so that the 4 → 3 downshift is smooth. Next, whether or not the rotation synchronization of the clutch C1 indicating the achievement of the third gear is performed in SC4 corresponding to the synchronization determination means 126 is determined by the counter rotation speed N_CAnd turbine rotation speed N_TIs determined based on whether or not is matched. If the determination of SC5 is negative, the above SC3 and subsequent steps are repeatedly executed. If the determination is positive, the engagement pressure P of the clutch C1 is determined in SC5._C1Starts to rise. T in FIG._FiveThe time point indicates this state. Engagement pressure P at this time_C1Is the duty ratio D of the drive signal to the linear solenoid valve SL3 in FIG._SL3As shown in FIG. 5, the rotation speed is changed in the direction of rapid increase when the rotation is synchronized, and then gradually increased and then increased to the maximum value.
[0033]
As described above, according to the present embodiment, when the clutch-to-clutch downshift executed during coasting is performed by the minute drive state control unit 134 (SA4, SA5, SA9), the input shaft rotational speed state detection unit 128 performs. Detected actual input / output rotational speed difference N_SLIPBased on engine speed N_EAs a result of the increase control being performed, the vehicle is maintained in a minute drive state during the clutch-to-clutch downshift. When clutch-to-clutch downshift control during coasting is performed in such a minute driving state, torque fluctuation is small, so that high hydraulic control accuracy of the brake B1 and clutch C1 involved in the shift is obtained, and high control accuracy is obtained. Even without an expensive device equipped with a vehicle, sufficient robustness against disturbances such as vehicle braking can be obtained.
[0034]
Further, according to the present embodiment, the minute drive state control means 134 (SA4, SA5, SA9) is an engine rotation speed N that is controlled to increase in order to bring the vehicle into a minute drive state._EIncrease ΔN_ETherefore, when the vehicle speed V decreases during braking, the engine rotation speed increase amount ΔN that is controlled to increase to bring about a minute driving state accordingly._EEngine speed N_EAnd the input / output rotational speed difference N of the torque converter (fluid transmission) 12_SLIPThere is an advantage that the minute driving state is maintained even at the time of vehicle braking in which the vehicle tends to increase. Therefore, the engine speed increase amount ΔN_EIf there is no decrease, it becomes difficult to engage the clutch C1, which is the engagement-side hydraulic friction engagement device, at the end by the hydraulic control of the clutch-to-clutch 4 → 3 downshift. For example, the clutch C1 can be easily engaged at the end of shifting.
[0035]
Further, according to this embodiment, the synchronization determination means 126 (SC4) for determining whether or not the rotation of the clutch C1, which is an engagement-side hydraulic friction engagement device involved in the clutch-to-clutch 4 → 3 downshift, is synchronized. ), And the synchronization determination means 126 determines the rotation synchronization of the clutch C1, the engagement pressure P of the clutch C1_C1Is further provided with engagement side engagement pressure control means 124 (SC3, SC5) that rapidly increase the standby pressure from the previous standby pressure, so that when the rotation synchronization of the clutch C1 is determined, the engagement of the clutch C1 is determined. Combined pressure P_C1Is quickly increased from the standby pressure until then, so that the shift can be completed quickly without causing a shift shock.
[0036]
  Further, according to the present embodiment, when the sudden braking state determination unit 136 (SA1) for determining the sudden braking state of the vehicle and the sudden braking state determination unit 136 determines the sudden braking state of the vehicle, Minute drive control stop means for immediately stopping the engine speed increase control for making the minute drive state continued from the previous 5 → 4 coast down shift output.138(SA2) is further provided, so that when the sudden braking state of the vehicle is determined, the engine for making the minute driving state continued from the previous 5 → 4 coast downshift output There is an advantage that the control for increasing the rotational speed is immediately stopped and the influence on the subsequent clutch-to-clutch 4 → 3 coast down shift control is eliminated.
[0037]
Further, according to the present embodiment, the minute drive state control means 134 is the engine rotation speed for setting the vehicle in the minute drive state from the vicinity of the start of the inertia phase of the clutch-to-clutch 4 → 3 down shift executed during coasting. In the clutch-to-clutch shift where fine hydraulic control is required, the minute drive state is maintained after the start of the inertia phase and the previous coast down shift output is continued. The influence is reduced as much as possible by the minute driving state.
[0038]
As mentioned above, although one Example of this invention was described based on drawing, this invention is applied also in another aspect.
[0039]
For example, the minute drive state control means 134 of the above-described embodiment is configured so that the engine speed N_EThe ISC valve 54 is used to raise the predetermined amount, but the throttle actuator 50 that drives the throttle valve 52, the fuel injection valve that adjusts the fuel injection amount for the engine 10, and the ignition timing of the engine 10 are adjusted. Another engine rotation speed adjusting device such as an ignition timing adjusting device may be used.
[0040]
Further, the minute driving state control means 134 of the above-described embodiment is provided with the counter rotational speed N corresponding to the vehicle speed V._CEngine speed increase amount N according to the decrease rate of_ECounter rotation speed N_CInstead, other parameters such as wheel rotation speed may be used.
[0041]
Further, although the minute driving state control means 134 of the above-described embodiment starts the minute driving control from the inertia phase starting point after the 4 → 3 downshift, it does not necessarily have to be from the inertia phase starting point. → Any time after 3 downshift output.
[0042]
In the above-described embodiment, the input / output rotational speed difference N of the torque converter 12 is_SLIPHowever, a fluid coupling may be used instead of the torque converter 12.
[0043]
Further, the aforementioned input / output rotational speed state detection means 128 is provided with an input / output rotational speed difference N of the torque converter 12._SLIPHowever, it may be an input / output rotational speed ratio. In this case, the aforementioned input / output rotational speed difference N_SLIPIs replaced by the input / output rotational speed ratio.
[0044]
Further, the automatic transmission 14 of the above-described embodiment may be other types. For example, the automatic transmission 14 is for FF (front engine-front drive) and is configured to obtain forward 5 speed, but is configured to obtain forward 4 speed or less or forward 6 speed or more. Alternatively, it may be configured for FR (front engine-rear drive).
[0045]
In the above-described embodiment, the 4 → 3 downshift of the automatic transmission 14 has been described. However, other downshifts such as a 3 → 2 downshift may be used.
[0046]
Although not exemplified one by one, the present invention can be carried out in various modifications and improvements based on the knowledge of those skilled in the art.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram illustrating a configuration of an automatic transmission for a vehicle to which an embodiment of the present invention is applied.
2 is an engagement operation chart illustrating an engagement operation of a clutch and a brake for establishing each gear position of the automatic transmission of FIG. 1. FIG.
FIG. 3 is a block diagram for explaining a shift electronic control unit and the like provided in the vehicle for controlling the automatic transmission of FIG. 1;
4 is a diagram showing a relationship between an accelerator pedal operation amount and a throttle valve opening used for control of a throttle valve opening by the electronic control unit of FIG. 3; FIG.
5 is a diagram showing a shift diagram used for shift control of an automatic transmission by the shift electronic control device of FIG. 3; FIG.
6 is a hydraulic circuit diagram schematically illustrating a configuration of a main part of the hydraulic control circuit in FIG. 3. FIG.
7 is a functional block diagram illustrating an example of a control function by the shift electronic control device of FIG. 3 and illustrating a main part of the control function. FIG.
8 is a diagram showing a relationship used for determining an initial hydraulic pressure in the engagement side engagement pressure control unit or the release side engagement pressure control unit of FIG. 7;
9 is a diagram showing a relationship used for determining an engine rotational speed lifting amount (ISC valve required amount) in the minute driving state control means of FIG. 7; FIG.
10 is a diagram showing a relationship used for determining a reduction rate of an engine rotational speed lifting amount based on a turbine rotational speed reduction rate in the minute driving state control means of FIG. 7; FIG.
11 is a flowchart for explaining a main part of a control operation by the shift electronic control device of FIG. 3, and shows a minute drive control routine.
12 is a flowchart for explaining a main part of the control operation by the speed change electronic control unit of FIG. 3, and shows a disengagement side engagement pressure control routine.
FIG. 13 is a flowchart for explaining a main part of the control operation by the shift electronic control device of FIG. 3, showing an engagement side engagement pressure control routine;
14 is a time chart for explaining a main part of a control operation by the shift electronic control device of FIG. 3; FIG.
[Explanation of symbols]
10: Engine
12: Torque converter (fluid transmission)
14: Automatic transmission
120: Shift control means
124: Engagement side engagement pressure control means
126: Synchronization determination means
128: Input shaft rotational speed state detection means
130: Inertia phase determination means
134: Minute drive state control means
136: Rapid braking state determination means
138: Minute drive control stop means
C1: Clutch (engagement side hydraulic friction engagement device)
B1: Brake (release hydraulic friction engagement device)

Claims (3)

Achieved by releasing the release-side hydraulic friction engagement device and engaging the engagement-side hydraulic friction engagement device in an automatic transmission for a vehicle in which torque transmitted from the engine is input via a fluid transmission A shift control device for a vehicle automatic transmission of a type that executes a clutch-to-clutch downshift during coasting,
An input / output rotational speed difference detecting means for detecting an input / output rotational speed difference of the fluid transmission device;
During clutch-to-clutch downshifting executed during coasting, the vehicle is controlled by increasing the rotational speed of the engine based on the input / output rotational speed difference detected by the input / output rotational speed difference detecting means. A minute driving state control means for making a minute driving state;
Synchronization determination means for determining whether or not the rotation of the engagement-side hydraulic friction engagement device involved in the clutch-to-clutch downshift is synchronized;
When the synchronization determination means determines that the rotation of the engagement-side hydraulic friction engagement device is synchronized, the engagement pressure of the engagement-side hydraulic friction engagement device is quickly increased from the previous standby pressure. An engagement-side engagement pressure control means for controlling the automatic transmission for a vehicle. Achieved by releasing the release-side hydraulic friction engagement device and engaging the engagement-side hydraulic friction engagement device in an automatic transmission for a vehicle in which torque transmitted from the engine is input via a fluid transmission A shift control device for a vehicle automatic transmission of a type that executes a clutch-to-clutch downshift during coasting,
An input / output rotational speed difference detecting means for detecting an input / output rotational speed difference of the fluid transmission device;
During clutch-to-clutch downshifting executed during coasting, the vehicle is controlled by increasing the rotational speed of the engine based on the input / output rotational speed difference detected by the input / output rotational speed difference detecting means. A minute driving state control means for making a minute driving state;
Sudden braking state determining means for determining a sudden braking state of the vehicle;
When the sudden braking state of the vehicle is determined by the sudden braking state determination means, the engine speed of the engine for making the minute driving state already executed from the previous clutch-to-clutch coast downshift output is continued. A shift control device for an automatic transmission for a vehicle, comprising: minute drive control stop means for immediately stopping the increase control. 3. The vehicle according to claim 1, wherein the minute driving state control means is configured to decrease an increase amount of an engine rotation speed that is increased in order to bring the vehicle into a minute driving state as the vehicle speed decreases. A shift control device for an automatic transmission.

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