JPH10331962A - Change gear control method of automatic transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent change gear feeling from worsening by compensating an initial oil pressure command value supplied to a friction engaging element on high speed side by an evaluation index based on changes of input rotation speed at an initial inertia phase. SOLUTION: For example, when speed is changed from a first speed step to a second speed step, a high speed side oil pressure command value is changed to the maximum oil pressure command value in a condition in which a low speed side oil pressure command value is held to the minimum oil pressure command value. After that, the presence or absence of the occurrence of 'rotation blowing up' is judged based on the already memorized results (S111). When it is judged that it exists, a deviation amount ΔCi from a proper value of an initial oil pressure command value Ci is calculated from the maximum control deviation emax of rotation acceleration of an input shaft at an initial inertia phase (S112). The initial oil pressure command value Ci (n+1) used at the time of next up shift is calculated by adding the deviation amount ΔCi to the initial oil pressure command value Ci (n) and is memorized (S113), and the learning control is done using this value as the initial oil pressure command value at the time of next up shift.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission for a vehicle, and more particularly to a shift control method for starting an upshift.
A low-speed friction that is driven by hydraulic pressure to establish a low-speed gear stage after a predetermined time has elapsed by supplying hydraulic pressure to a high-speed friction engagement element that establishes a high-speed gear stage by driving hydraulic pressure. The engagement element is disengaged by removing the hydraulic pressure supplied to the engagement element, and in the subsequent inertia phase, the rate of change of the rotation speed of the input shaft in the gear transmission follows the target change rate set in advance. The present invention relates to a shift control method for an automatic transmission for a vehicle in which an upshift is controlled by feedback-controlling a hydraulic pressure supplied to the high-speed side friction engagement element.

[0002]

2. Description of the Related Art In this type of control method, pattern control is performed from the start of an upshift to the time of an inertia phase. If the value is larger than the set value, "torque interference" is caused. If the initial oil pressure value with respect to the initial oil pressure command value is lower than the set value, "rotational blow-up" is caused to deteriorate the shift feeling. There is a problem.

In order to solve such a problem, in the prior art (Japanese Patent Laid-Open No. 3-113162), when the measured time of the inertia phase is shorter than the target value, the initial oil pressure command value is decreased so as to decrease the initial oil pressure value at the next upshift. And when the measured time of the inertia phase is longer than the target value, the initial oil pressure command value is changed so as to increase the initial oil pressure value at the next upshift. Further, in the related art (Japanese Patent Laid-Open No. 5-296333), a deviation between an actual measurement time from a reference time to an inertia phase and a predetermined standard time is obtained.
The hydraulic supply speed to the high-speed friction engagement element at the next shift-up is corrected according to the obtained deviation. For example, if the measured time is longer than a predetermined standard time, the high-speed friction engagement at the next shift-up is corrected. This is dealt with by changing the initial hydraulic pressure command value so as to increase the hydraulic pressure supply speed to the element.

[0004]

In the above-mentioned prior art (JP-A-3-113162), the actual measurement time of the inertia phase affected by the feedback control is used as the evaluation index. If the cause of the increase is due to the feedback control itself, "torque interference" or "rotational blow-up" may not be properly eliminated, and the shift feeling may not be good.

In addition, the above-mentioned prior art (Japanese Patent Laid-Open No. 5-29
In 6333), all the causes of the above-mentioned deviation are determined from the deviation of the relationship between the initial hydraulic pressure command value and the initial hydraulic pressure value. Therefore, since the invalid stroke in the high-speed side frictional engagement element has increased, the inertia phase has changed from the reference time. When the actual measurement time is long, the initial oil pressure value is excessively increased, and as shown in FIG. 8, the change in the output shaft torque becomes sharper than at the time of the target shift pattern shown by the broken line. The shift feeling may be deteriorated.

[0006]

According to the present invention, an evaluation index based on a change in the rotation speed of an input shaft at the beginning of an inertia phase has a predetermined relationship with a deviation amount of an initial hydraulic pressure command value from an appropriate value. Based on the knowledge of the inventor, it has been made to address the above-described problems, and at the start of an upshift, hydraulic pressure is supplied to a high-speed friction engagement element that is driven by hydraulic pressure to establish a high-speed gear position. After a predetermined time has elapsed, the hydraulic pressure supplied to the low-speed friction engagement element that is driven by the hydraulic pressure to establish the low-speed gear stage is eliminated to release the engagement, and the inertia phase The upshift is controlled by feedback controlling the hydraulic pressure supplied to the high-speed side frictional engagement element so that the change rate of the rotation speed of the input shaft in the gear transmission follows a preset target change rate. Vehicle In the speed change control method for an automatic transmission, the evaluation index (for example, the maximum control deviation emax shown in FIG. 6) based on a change in the rotation speed of the input shaft at the beginning of the inertia phase may be used to set the high speed The amount of deviation of the initial oil pressure command value for obtaining the initial oil pressure value supplied to the side friction engagement element from the appropriate value is obtained, and the initial oil pressure command value obtained by correcting this deviation amount is used for the next upshift. It is characterized in that learning control is performed with the initial hydraulic pressure command value at the time.

[0007]

In the shift control method according to the present invention, the evaluation index based on the change in the rotation speed of the input shaft at the beginning of the inertia phase, which is hardly affected by the feedback control in the inertia phase, for example, FIG. As shown in the above, the deviation ΔCi of the initial oil pressure command value Ci from the appropriate value and the predetermined amount ΔCi are almost unaffected by the change in the invalid stroke (deviation of the clutch piston clearance from the reference value) of the high-speed friction engagement element. Since the deviation ΔCi is obtained using the maximum control deviation emax of the rotational acceleration of the input shaft in the relationship of the evaluation as an evaluation index, the influence of the feedback control in the inertia phase and the influence of the change of the invalid stroke of the high-speed friction engagement element are considered. The initial oil pressure command value can be corrected with almost no reception, and appropriate control can be performed in the next upshift control. It works.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The vehicle automatic transmission shown in FIG. 1 includes a torque converter 20 and a gear transmission (A / G) connected to an output shaft (not shown) of an engine (E / G) 10.
T) 30 (see FIG. 2), hydraulically driven first and second clutches C1 and C2, and hydraulically driven first and second brakes B1 and C2 incorporated in the gear transmission 30 shown by a skeleton in FIG. A known hydraulic control device 40 that controls each operation of Bo and the reverse brake B2, and a plurality of solenoid valves (not shown) in the hydraulic control device 40 (a known hydraulic control valve that is duty-controlled based on a hydraulic command value) ) Is configured by an electronic control unit (ECU) 50 or the like that controls the operation of (1).

As shown in FIG. 2, the gear transmission 30 receives the power transmitted from the engine 10 via the torque converter 20 through the input shaft 31 and outputs the power to the output shaft 32. 33, a planetary gear train composed of a carrier 34 and a ring gear 35, and a planetary gear train composed of a sun gear 36, a carrier 37 and a ring gear 38. Indicates an operation-on state, and no mark indicates an operation-off state).
When the first clutch B2 and the first brake B1 are both turned on, the first speed is established, and the second clutch C2 and the first
When both brakes B1 are turned on, 2
A third speed is established by turning on both the first clutch C1 and the second clutch C2, and a third speed is established by the second clutch C2 and the second brake Bo.
Are in the operation-on state, a fourth speed is established, and when both the first clutch C1 and the reverse brake B2 are in the operation-on state, the reverse speed is established. ing.

The electronic control unit 50 includes a microcomputer, and detects an engine speed Ne of an output shaft of the engine 10 (Ne sensor) 5.
1. Rotation speed of input shaft 31 of gear transmission 30 (corresponding to rotation speed of turbine 21 of torque converter 20) Nt
Input shaft speed sensor (Nt sensor) 5 for detecting
2. An output shaft rotation speed sensor (No sensor) 53 for detecting the rotation speed (corresponding to the vehicle speed of the vehicle) No of the output shaft 32 of the gear transmission 30, the throttle opening of the engine 10 (corresponding to the engine load). A throttle opening sensor (θ sensor) 54 for detecting θ is connected to each other, and by executing a program corresponding to the flowchart of FIG. 4, a shift control at the time of upshifting is performed, and a program corresponding to the flowchart of FIG. , The learning control of the initial hydraulic pressure command value at the time of the next upshift is performed.

Next, the operation at the time of an upshift executed by the electronic control unit 50 will be described with reference to FIGS. 4 to 7 by taking as an example the case of shifting up from the first gear to the second gear. The timing for shifting up from the 1st gear to the 2nd gear in the automatic transmission (set so that "rotational blow-up" always occurs at the time of the first upshift after manufacture or connection to the battery). As is well known, when the shift start command signal is output (at the start of the shift in FIG. 7), the electronic control unit 50 starts executing the program in step 100 of FIG.
01, the hydraulic pressure supplied to the second clutch C2, which is the high-speed friction engagement element, is increased at the maximum speed while the hydraulic pressure supplied to the first clutch C1, which is the low-speed friction engagement element, is maintained. The high-speed side hydraulic command value (see the thick solid line of the hydraulic command value in FIG. 7) is changed from the minimum hydraulic command value to the maximum while the side hydraulic command value (the thin solid line of the hydraulic command value in FIG. 7) is held at the maximum hydraulic command value. Change to the oil pressure command value, start the timer in step 102,
At 03, the measurement time t of the timer is equal to the predetermined preceding injection time t.
i (when the predetermined time in FIG. 7 has elapsed).

At step 104 in FIG. 4, the high-speed hydraulic command value is changed from the maximum hydraulic command value to the initial hydraulic command value Ci, and the low-speed hydraulic command value is changed from the maximum hydraulic command value to the minimum hydraulic command value. When the time during which the input shaft rotation speed is higher than the first-speed synchronous rotation speed and the time during which the input shaft rotation speed is higher than the first-speed synchronous rotation speed by the repetition of step 105 is equal to or more than the set value, the "rotational blow-up" is stored. In step 106, it is determined whether or not the first gear is out of synchronization (inertia phase start) based on whether or not the input shaft rotation speed has become a value lower than the first speed synchronization rotation speed by a predetermined amount. It should be noted that a predetermined time (for example,
The change of the high-speed side oil pressure command value from the maximum oil pressure command value to the initial oil pressure command value Ci is started earlier, and the change to the initial oil pressure command value Ci is performed at a predetermined oil pressure decreasing gradient. It is also possible to carry out the modification so that the initial oil pressure command value Ci is accurately obtained when the predetermined preceding injection time ti has been reached.

In step 107 of FIG. 4, a well-known feedback control for controlling the high-speed side hydraulic command value so that the rate of change (rotational acceleration) of the rotational speed of the input shaft follows a preset target rate of change is executed. The period from the start of the inertia phase to the time when the input shaft rotation speed at the start of the inertia phase decreases by a predetermined rotation speed (for example, several hundred rotations in terms of the number of rotations of the input shaft) by repeatedly executing step 108. ) Is stored, and in step 109, synchronization with the second gear (inertia) is determined based on whether or not the input shaft rotation speed has become a predetermined value higher than the second-gear synchronous rotation speed. Phase end). In step 110, the high-speed side hydraulic command value is changed to the maximum hydraulic command value while the low-side hydraulic command value is held at the minimum hydraulic command value. Note that the change of the high-speed side hydraulic command value to the maximum hydraulic command value may be performed at a predetermined hydraulic pressure rising gradient.

As is apparent from the above description, when the upshift from the first gear to the second gear is started, the second clutch C2 which establishes the second gear in cooperation with the first brake B1 in the operation-on state has a maximum. The hydraulic pressure is supplied to start engagement of the second clutch C2, and after a lapse of a predetermined preceding injection time ti, supply to the first clutch C1 which establishes the first gear in cooperation with the first brake B1 in the operation ON state. The applied hydraulic pressure is removed, the engagement in the first clutch C1 is released, and in the subsequent inertia phase, the second clutch is controlled so that the rate of change of the rotational speed of the input shaft follows a preset target rate of change. The hydraulic pressure supplied to C2 is feedback-controlled, and the upshift from the first gear to the second gear is controlled.

By the way, in step 111 of FIG. 5 executed after execution of step 110 of FIG. 4, a storage result (stored in the storage means of the electronic control unit 50) obtained by repeatedly executing step 105 of FIG. ), It is determined whether or not a “rotational blow-up” has occurred,
If "YES" is determined, steps 112 and 11
After the execution of step 3, the program execution is terminated in step 114. When it is determined “NO” in step 111, the execution of the program is immediately terminated in step 114.

In step 112 of FIG. 5, the maximum control deviation obtained by repeatedly executing step 108 of FIG. 4 using the relationship shown in FIG. 6 (prestored in the storage means of the electronic control unit 50). Initial hydraulic command value Ci from emax
Is calculated from the appropriate value of .DELTA.Ci. In step 113, the initial oil pressure command value Ci (n + 1) used in the next upshift is shifted from the initial oil pressure command value Ci (n) used in step 104 by .DELTA.Ci. Is calculated and stored.

As described above, in this embodiment, the evaluation index based on the change in the rotation speed of the input shaft at the beginning of the inertia phase, which is hardly affected by the feedback control in the inertia phase, that is, shown in FIG. As described above, the initial hydraulic command value Ci is not affected by the change in the invalid stroke of the clutch piston (deviation from the reference value of the clutch piston clearance) in the second clutch C2 as the high-speed side frictional engagement element. Deviation amount ΔCi
And the maximum control deviation emax itself in a predetermined relationship is used as an evaluation index to determine the deviation amount ΔCi. Therefore, the influence of the feedback control in the inertia phase and the invalidity of the clutch piston in the second clutch C2 which is the high-speed side friction engagement element. The initial hydraulic command value Ci can be corrected almost without being affected by a change in the stroke, and appropriate control can be performed in the next upshift control from the first gear to the second gear, and the shift can be performed. Feeling can be improved.

The operation for shifting up from the second gear to the third gear and the operation for shifting up from the third gear to the fourth gear in the automatic transmission are the same as those described in the first embodiment.
The operation is substantially the same as the operation in the case of shifting up from the second gear to the second gear, so that the description is omitted.

In the above embodiment, the initial oil pressure command value
The maximum value that has a predetermined relationship with the deviation amount ΔCi from the appropriate value of Ci.
The large control deviation emax itself (the characteristic indicated by the solid line in FIG. 6)
Line) as an evaluation index to calculate the deviation amount ΔCi.
Is the approximate straight line indicated by the imaginary line in FIG.
The deviation amount ΔC is used as an evaluation index.
i may be required, and as a bodily sensation,
When transmitting torque, there is no problem even if the torque change is slightly large.
On the other hand, when transmitting low torque, a slight change in torque causes a feeling of strangeness
So that the evaluation index matches the experience,
The control deviation emax is calculated as the input shaft torque T immediately before the inertia phase.
divided by t (turbine torque calculated by the following formula)
It is also possible to carry out the evaluation as an evaluation index. Tt = τ (e) × C (e) × Ne^Two  Here, Tt: input shaft torque (turbine torque) Ne: engine rotation speed e = Nt / Ne: torque converter speed ratio Nt: input shaft rotation speed (turbine rotation speed) τ (e): torque converter torque ratio C (e) : Capacity coefficient of torque converter τ (e) and C (e) are obtained experimentally.
You. The above equation can be stored as a map.
It is possible.

Further, since an evaluation index based on a change in the rotation speed of the input shaft at the beginning of the inertia phase is used as the evaluation index, the time from when the input shaft rotation speed starts decreasing until the input shaft rotation speed decreases by several hundred rotations is used. The same relationship as in FIG. 6 can be obtained by using a value obtained by dividing the (initial phase of inertia time) by the target value of the inertia phase time as an evaluation index. Therefore, the present invention can be implemented using this as an evaluation index.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an automatic transmission for a vehicle.

FIG. 2 is a skeleton diagram of the torque converter and the gear transmission shown in FIG. 1;

3 is an operation display diagram of each clutch and each brake shown in FIG. 2;

FIG. 4 is a flowchart showing a shift control procedure during an upshift.

FIG. 5 is a flowchart showing a learning control procedure for correcting an initial hydraulic pressure command value at the time of the next upshift.

FIG. 6 is an initial hydraulic pressure command value C at the time of rotational upflow.
FIG. 7 is a diagram illustrating a relationship between a deviation amount ΔCi from an appropriate value of i and a maximum control deviation emax of a rotational acceleration of an input shaft at an early stage of an inertia phase.

FIG. 7 shows an input shaft rotation speed during an upshift,
It is a figure which shows each change characteristic of a clutch hydraulic pressure, a hydraulic command value, and a clutch transmission torque.

FIG. 8 is a diagram illustrating respective change characteristics of an input shaft rotation speed, a hydraulic pressure supplied to a friction engagement element, a hydraulic pressure command value, and an output shaft torque during an upshift in a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Engine, 20 ... Torque converter, 30 ... Gear transmission, 31 ... Input shaft, 32 ... Output shaft, 40 ... Hydraulic control device, 50 ... Electronic control device, C1 ... 1st clutch (high pressure side friction engagement element) , C2: second clutch (low-pressure side friction engagement element), B1: first brake, Bo: second brake, B2: reverse brake.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsutoshi Sato 2-1-1 Asahi-machi, Kariya-shi, Aichi Prefecture Inside Aisin Seiki Co., Ltd. (72) Inventor Hiroyuki Nishizawa 41-41 Of Toyota Central Research Institute, Inc.

Claims (1)

[Claims] 1. At the start of an upshift, hydraulic pressure is supplied to a high-speed friction engagement element for driving to establish a high-speed gear stage by hydraulic pressure to start engagement. The hydraulic pressure supplied to the low-speed friction engagement element that establishes the low-speed gear stage is eliminated to release the engagement, and in the subsequent inertia phase, the rate of change of the rotation speed of the input shaft in the gear transmission is set in advance. In the shift control method for an automatic transmission for a vehicle, wherein an upshift is controlled by feedback-controlling a hydraulic pressure supplied to the high-speed friction engagement element so as to follow a set target change rate. According to an evaluation index based on a change in the rotation speed of the input shaft at an initial stage, whether the initial hydraulic pressure command value for obtaining the initial hydraulic pressure value to be supplied to the high-speed side friction engagement element after the lapse of the predetermined time is appropriate. The vehicle is characterized by performing learning control in which the deviation amount is obtained, and the initial hydraulic pressure command value obtained by correcting the deviation amount is used as the initial hydraulic pressure command value at the time of the next upshift. Shift control method for automatic transmission.