JPH07174217A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To restrain the fluctuation of liquid pressure due to the response delay of a liquid system to prevent a speed change shock by correcting a quick filling time so that an oil pressure keeping time, until the beginning of an inertia phase at the time of a speed change, can conform to a target oil pressure keeping time to be set based on the delay time of the liquid system. CONSTITUTION:This speed change control device 1 has a quick filling time map part 31, and here control is performed so that a quick filling time QT can be determined based on the output of a throttle opening sensor 2 and a oil temperature sensor 4 to full-open the solenoide valve of an oil pressure control circuit part 12 for only this time TQ. Also a judgement part 32 is provided, which judges the beginning of an inertia phase, the start of a speed change, based on the output of an input shaft engine speed sensor 3, and also operates a clutch oil pressure keeping time Tk from quick filling time finish to an inertia start. Then a difference between a clutch oil pressure keeping time Tk and a target clutch oil pressure keeping time TkR is determined in a drift detection part 33 to correct the quick filling time TQ by a correction logic part 34 according to this difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission (A
The present invention relates to control of the liquid pressure supplied to the friction element of the speed change mechanism as engagement pressure.

[0002]

2. Description of the Related Art Conventionally, as techniques in this field, an input shaft of an automatic transmission to which engine power is input, an output shaft that outputs rotational power to drive wheels, and a friction engagement element that operates according to liquid pressure. 2. Description of the Related Art There is known an automatic transmission having a speed change mechanism in which a power transmission path is switched by a control element for controlling the friction engagement pressure by a liquid pressure.

As a means for controlling the engagement pressure of the friction element of the transmission, there is one disclosed in Japanese Patent Publication No. 35292/1993. This has a feedback control function so that an appropriate hydraulic pressure is fed to the friction engagement element during a gear shift, and the hydraulic pressure fed to the friction engagement element is fed to the friction engagement element in the latter half of the gear shift. Calculate the initial hydraulic pressure for gear shifting,
A so-called learning control is performed in which this hydraulic pressure is used as an initial hydraulic pressure for the next shift.

[0004]

By the way, a phenomenon occurs in which the clutch of the friction engagement element absorbs the inertia (inertia) of the engine or the like. Therefore, the inertia phase is from the start to the end of the change in the turbine speed of the torque converter. Generally called. In the above initial hydraulic control, it is considered that the liquid pressure at the start of the inertia phase is learned and obtained. However, in the control of the initial hydraulic pressure, when the liquid pressure is rapidly increased, that is, the solenoid valve is fully opened during the rapid filling, the filling time of the clutch is shortened,
Although the time until the start of the inertia phase can be shortened, there is a problem in that even if the command for the solenoid valve is changed from full-open to the liquid pressure at the start of the inertia phase, the liquid pressure does not fall due to the response delay of the liquid system. Therefore, even if the fluid pressure command at the start of the inertia phase is learned to an appropriate value, if the time from the end of rapid filling to the start of inertia is short, the actual fluid pressure becomes higher due to the command value, and a shift shock occurs. To do.

In Japanese Patent Publication No. 5-42581, the engagement position of the friction engagement element is detected by a stroke sensor attached to the friction engagement element, and the fluid pressure is rapidly increased until a preset stroke position is reached. After that, a means for setting the liquid pressure to a low level is described. According to this method,
The problem does not occur by rapidly increasing the liquid pressure, but there is a problem that the structure becomes complicated because a stroke sensor is required.

Therefore, in view of the above problems, the present invention provides a shift control device for an automatic transmission, which can prevent the occurrence of shift shock caused by rapidly increasing the fluid pressure without using a stroke sensor. With the goal.

[0007]

In order to solve the above problems, the present invention provides an input shaft of an automatic transmission to which engine power is input, and an output shaft which outputs rotational power to drive wheels.
An automatic transmission having a speed change mechanism whose power transmission path is switched by a friction engagement element that operates according to liquid pressure, and including a control element that controls the engagement pressure of the speed change engagement element by liquid pressure. Occasionally, when performing a control method to increase the liquid pressure rapidly by rapid filling and then maintain the liquid pressure according to the running condition, the inertia phase in which the rotation speed of the input shaft changes after the liquid pressure is maintained The rapid filling time is corrected so that the hydraulic pressure holding time of is matched with the target hydraulic pressure holding time set based on the delay time of the liquid system.

[0008]

According to the shift control device for an automatic transmission of the present invention,
When the liquid pressure is rapidly increased by rapid filling at the time of gear shifting and then maintained at the liquid pressure according to the running condition, from the time the liquid pressure is maintained until the inertia phase in which the rotation speed of the input shaft changes The rapid filling time is corrected so that the hydraulic pressure holding time of (1) matches the target hydraulic pressure holding time set based on the delay time of the liquid system, whereby the time until the start of the inertia phase can be shortened by the rapid filling. Further, by holding the hydraulic pressure holding time at the target holding time after the rapid filling, it is possible to suppress the fluctuation of the liquid pressure due to the response delay of the liquid system and prevent the occurrence of the shift shock. Specifically, when the hydraulic pressure holding time is shorter than the target holding time, the hydraulic pressure holding time is adjusted so that the hydraulic pressure holding time becomes larger than the target holding time by quickly correcting the rapid filling time. When the time is longer than the target time, the quick filling time is gradually corrected so that the hydraulic pressure holding time does not become shorter than the target holding time, so that the shift shock can be prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of a shift control device for an automatic transmission according to an embodiment of the present invention. In this figure,
The automatic transmission includes a hydraulic torque converter 10 for inputting and transmitting the output of the engine, a planetary gear connected to the torque converter 10, a clutch as a friction engagement element, a brake, and the like, and has a plurality of gear ratios. The transmission 11 includes a hydraulic control circuit 12 for automatically controlling the gear ratio of the transmission 11 according to the vehicle speed and the output of the engine. Further, the automatic transmission has a shift control device 1 in which a solenoid valve is incorporated in the hydraulic control circuit section 12 to control the solenoid valve. The shift control device 1 is an ECU (Electronic Control Un
it).

The shift control device 1 includes a throttle opening sensor 2
, An input shaft rotation speed sensor 3 attached to the input shaft of the transmission 11, and an oil temperature sensor 4 for detecting the oil temperature used.
And a signal from the output speed sensor 5 attached to the output shaft of the transmission 11, a control command for the solenoid valve of the transmission 11 is calculated. 2 is a diagram showing a configuration of the hydraulic control circuit unit 12 of FIG. 1, and FIG. 3 is a diagram showing a schematic configuration of the transmission 11 of FIG. Hydraulic control circuit unit 12 shown in FIG.
Includes a hydraulic pressure source 21, a pressure regulator valve 22 that regulates the hydraulic pressure from the hydraulic pressure source 21 to generate a line pressure (PL), and a solenoid valve 23 that adjusts the line pressure (PL) by the shift control device 1. It is composed of a clutch 24 to which a clutch hydraulic pressure whose line pressure (PL) is adjusted by the electromagnetic valve 23 is supplied. By this clutch 24, each element of a known O / D planetary gear as shown in FIG. 3 is fixed,
Open switching is performed. The hydraulic pressure that operates the piston that constitutes the clutch 34 is finely adjusted by the solenoid valve 23. The electromagnetic valve 23 is normally electrically controlled based on the voltage duty ratio of the ECU 1 described above.

Next, the shift control device 1 will be described.
The shift control device 1 shown in FIG.
And a quick fill time map unit 31 connected to the oil temperature sensor 4 to obtain the quick fill time TQ and fully opening the solenoid valve 23 of the hydraulic control circuit unit 12 for this time, and a gear shift connected to the input shaft speed sensor 3. The inertia phase determination unit 32 that determines the start of the inertia phase, which is the start, and calculates the clutch hydraulic pressure holding time Tk from the end of the rapid filling time to the start of inertia, and the clutch hydraulic pressure holding time and the target clutch hydraulic pressure holding time TkR. A deviation detection unit 33 for obtaining a difference from TkR and a correction logic unit 34 for correcting the rapid filling time by the difference are provided.

FIG. 4 is a flow chart for explaining the correction algorithm of the rapid filling time in the shift control device 1 of FIG. 1, and FIG. 5 is a time chart for explaining the correction algorithm of FIG. As shown in FIG. 4, first, clutch hydraulic pressure control processing is performed. In step S1, the inertia phase determination unit 32 determines whether a gear shift has started.
If this judgment is "NO", this processing is ended.

In step S2, the above judgment is "YE
If "S", it is determined whether or not gear shifting is in progress. This judgment is "YES"
If so, this process ends. In this way, when it is detected that the shift command is issued and the shift is not currently being performed, the following initialization process is performed. In step S3, the quick filling time map unit 31 clears the timer. Set this timer value to T
Let's call it an imager.

In step S4, the quick filling time map section 31 calculates the quick filling time TQ using the throttle opening of the sensors 2 and 4 and the oil temperature data as parameters. The rapid filling time map unit 31 stores a map of the rapid filling time with the throttle opening as an operating condition and the oil temperature as parameters. In step S5, the quick filling time map unit 31 sets the quick filling control to the start state.
Next, a rapid filling control process is performed.

In step S6, the determination as to whether or not rapid filling should be performed is made based on whether the following equation is satisfied. Timer <TQ In step S7, if Timer has not passed TQ, the rapid filling time map unit 31 retrieves the rapid filling time TQ retrieved from the map at the same time as the shift command in step S4.
Only, the flow rate of the solenoid valve 23 is maximized, as indicated by reference numeral "10" in FIG.

In step S8, T in step S6
If the timer has passed the quick filling time TQ, the command value of the clutch hydraulic pressure according to the running state is calculated. In step S9, the shift control device 1 controls the voltage duty ratio related to the solenoid of the solenoid valve 23 while monitoring the input shaft speed from after the rapid filling until the engagement of the clutch is completed, and the clutch hydraulic pressure is changed. The command value is held so that is constant, as indicated by reference numeral "11" in FIG. When the clutch starts contacting, a state called a torque phase is established, and the transmission of force by the one-way clutch changes to the transmission of force by the one-way clutch and the clutch. However, in this state, gear shifting has not started and the input shaft speed (the turbine speed of the torque converter 10) does not change. After a while, the one-way clutch disengages, and force is transmitted only by the clutch. This instantaneous gear shift starts, and the input shaft speed, that is, the turbine speed of the torque converter 10 changes.

In step S10, the inertia phase determination unit 32 detects the drop ΔNt of the input shaft rotation speed by the sensor 3, and as shown by reference numeral "12" in FIG.
This drop amount is determined by the following formula. ΔNtR
> ΔNt, where ΔNtR is the reference input shaft rotation speed change amount. If this determination is "YES", rapid filling is continued.

In step S11, the above judgment is "N".
If “O”, that is, if the drop ΔNt of the input shaft machine rotation number is larger than the reference value ΔNtR, the rapid filling is terminated.
Here, since the phenomenon in which the clutch absorbs the inertia (inertia) of the engine or the like occurs, as described above, the inertia phase is from the start to the end of the shift, and the reference numeral "1" in FIG.
Generally, as shown in "3."

In step S12, the inertia phase determination unit 32 determines that the control of the inertia phase starts when the change Nt in the input shaft rotation speed becomes larger than the reference input shaft rotation speed change amount ΔNtR. In step S13,
The inertia phase determination unit 32 determines the time from the start of the clutch hydraulic pressure holding to the start of the inertia phase as the clutch hydraulic pressure holding time T.
Calculate k.

In step S14, the next rapid filling time is corrected. The details will be described below. FIG. 6 is a flow chart for explaining the next rapid filling time correction in step S14 of FIG. This figure shows a learning algorithm for the rapid filling time TQ. In step S20, the deviation detection unit 33 from TkR compares the clutch hydraulic pressure holding time Tk with the target holding time TkR as in the following equation to obtain the difference. The target holding time TkR is set from the delay time of the hydraulic system.

Tk <TkR In step S21, if the above judgment is "YES",
The gain G is set to G = 1.0. If the above determination is "NO" in step S22, the gain G is set to G = 0.1.
Set to.

In step S23, the correction logic unit 34 determines the rapid filling time TQ by the following equation. TQn + 1 = TQn + (Tk-TkR) * GTQ: Rapid filling time (n + 1; next time, n; current time) Tk: Current clutch hydraulic pressure holding time TkR: Target clutch hydraulic pressure holding time G: Feedback gain Here, switching of feedback gain Is done to reduce the number of shift shocks. Tk <TkR
In the case of, the fluid pressure at the start of the inertia phase does not fall to an appropriate value, so the clutch suddenly engages and a shift shock occurs. Therefore, the feedback gain G (= 1) is increased to accelerate the convergence so that Tk> TkR can be quickly achieved. Conversely, when Tk> TkR, the feedback gain G is set small so that Tk <TkR does not hold. In this way, in order to make the clutch hydraulic pressure holding time Tk follow the target clutch pressure holding time TkR set by the delay time of the hydraulic system, the rapid filling time TkR during time shifting is set.
And Tk are corrected. If the clutch pressure holding time is smaller than the target value, a shift shock will occur, so
The value of the feedback gain G is set to a large value to make a quick correction.

FIG. 7 is a diagram showing a modification of FIG. In steps S31 and S32, steps 21 and 22 in FIG.
Instead, a fixed time is provided, and in steps S33 and S34, the same effect can be obtained by obtaining the next rapid filling time by adding to the current rapid filling time. According to the present embodiment, by shortening the time until the start of the inertia phase by rapid filling and maintaining the clutch pressure after rapid filling, fluctuations in clutch hydraulic pressure due to response delay of the hydraulic system are suppressed and shift shock is prevented. To do.

Further, although the command to the solenoid valve is switched stepwise from full open to the appropriate value at the start of the inertia phase, the same effect can be obtained by switching it inclining.

[0025]

As described above, according to the present invention, the liquid pressure is rapidly increased by the rapid filling at the time of gear shifting, and then the liquid pressure is maintained when the liquid pressure is maintained at the liquid pressure according to the running state. Since the rapid filling time is corrected so that the hydraulic pressure holding time from the start of the inertia phase when the rotation speed of the input shaft changes to the target hydraulic pressure holding time set based on the delay time of the liquid system, The time from filling to the start of inertia phase can be shortened. Furthermore, since the hydraulic pressure holding time is held at the target holding time after rapid filling,
It is possible to prevent the shift shock from occurring by suppressing the fluctuation of the liquid pressure due to the response delay of the liquid system.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a shift control device for an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a hydraulic control circuit section 12 of FIG.

3 is a diagram showing a schematic configuration of a transmission 11 of FIG.

4 is a flowchart illustrating a correction algorithm for a rapid filling time in the shift control device 1 of FIG.

5 is a time chart for explaining the correction algorithm of FIG.

FIG. 6 is a flowchart illustrating the next rapid filling time correction in step S14 of FIG.

FIG. 7 is a diagram showing a modification of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shift control device 3 ... Input shaft rotation speed sensor 10 ... Torque converter 11 ... Transmission 12 ... Hydraulic control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Fujina 1-1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd.

Claims (2)

[Claims] 1. A power transmission path is switched by an input shaft of an automatic transmission to which engine power is input, an output shaft that outputs rotational power to drive wheels, and a friction engagement element that operates according to liquid pressure. In an automatic transmission having a speed change mechanism and having a control element for controlling the engagement pressure of the speed change engagement element by a liquid pressure, the liquid pressure is rapidly increased by quick filling during a speed change, and thereafter,
When maintaining the liquid pressure according to the running condition, the hydraulic pressure holding time from the holding of the liquid pressure to the start of the inertia phase where the rotation speed of the input shaft changes is a target set based on the delay time of the liquid system. A shift control device for an automatic transmission, wherein a rapid filling time is corrected so as to match a hydraulic pressure holding time. 2. When the hydraulic pressure holding time is shorter than the target holding time, the rapid filling time is corrected quickly so that the hydraulic pressure holding time is longer than the target holding time, and the hydraulic pressure holding time is The shift control of the automatic transmission according to claim 1, wherein when the time is longer than the target time, the rapid filling time is gently corrected so that the hydraulic pressure holding time does not become longer than the target holding time. apparatus.