JP3074395B2 - Hydraulic control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission which feedback-controls an operating oil pressure such as a line pressure and a clutch pressure of the automatic transmission during a gear shift.

[0002]

2. Description of the Related Art Generally, an automatic transmission for a vehicle generally includes a hydraulic control device including an oil pump, a pressure regulating valve, a pressure reducing valve, and the like, a friction engagement element such as a clutch and a brake controlled by the hydraulic control device. A rotating element such as a gear which is selectively engaged or disengaged by the operation of the friction engagement element, whereby an input shaft for inputting rotational power of the engine and an output shaft for outputting rotational power to drive wheels are provided. The change of the gear ratio between the two is automatically performed. Normally, the control by the hydraulic control device is performed by selectively operating an electromagnetic valve in a hydraulic circuit when it is detected that the traveling state of the vehicle has exceeded a predetermined shift line.

[0003] If the operating oil pressure supplied to the friction engagement element is rapidly increased between the start and the end of the shift, the friction engagement element is suddenly connected. There is a problem that an excessive load is applied to the automatic transmission and the engine due to a shift shock, and if the rise of the operating oil pressure is too slow, an excessive slip occurs in the friction engagement element and the life thereof is shortened. Problem. Therefore, in order to properly control the operating oil pressure supplied to the friction engagement element, for example, Japanese Patent Application Laid-Open No. 60-201152
In the automatic transmission for a vehicle described in Japanese Patent Application Laid-Open Publication No. H10-209, the rotational speed of a rotating element during a gear shift is detected, the rate of change is obtained from the detected rotational speed, and the rate of change follows a predetermined target value. The hydraulic pressure is controlled by providing feedback so as to control the hydraulic pressure.

[0004]

However, in the above-mentioned conventional feedback control, the gain amount is constant, and this gain is set to be small in order to perform stable control over the entire operation range. Inevitably, the response is poor in some areas, and it is difficult to respond and converge in a short time (about 0.3 to 0.6 seconds) during shifting.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to set an optimum gain corresponding to a hydraulic response when changing the operating oil pressure of an automatic transmission, thereby ensuring stability. Another object of the present invention is to realize feedback control with good responsiveness while realizing.

[0006]

SUMMARY OF THE INVENTION The present invention has a characteristic that the hydraulic response is fast when the hydraulic pressure before the change is high and slow to fall when the hydraulic pressure before the change is low, and vice versa when the hydraulic pressure before the change is low. Paying attention to this, the gain is changed in accordance with the hydraulic response, and the configuration is as shown in FIG. That is, the hydraulic control apparatus for an automatic transmission according to the present invention includes a hydraulic control unit that controls the operating hydraulic pressure of the automatic transmission in accordance with a shift state signal, and a control amount of the operating hydraulic pressure by the hydraulic control unit. In a hydraulic control apparatus for an automatic transmission including feedback correction means for performing feedback correction based on a deviation between a predetermined target amount and an actual amount of a state quantity related to a shift state of a shift state before a shift state changes. Pre-change hydraulic pressure detecting means for detecting the value of the operating hydraulic pressure, and the pre-change hydraulic pressure and the shift state detected by the pre-change hydraulic pressure detecting means.
A gain changing means is provided for changing the gain of the control by the feedback correcting means based on the oil pressure change direction determined from the signal .

The gain changing means is provided for increasing the operating oil pressure.
Control, the gain increases as the pre-change hydraulic pressure increases.
It is recommended that the hydraulic pressure be lowered
In the control to the side, the gain decreases as the pre-change hydraulic pressure increases.
It is better to set it up.

Further, the hydraulic control means, by adjusting the amount of drainage of the source pressure and that an electromagnetic valve to obtain a predetermined control pressure,
The gain changing means sets the gain to be larger as the pre-change hydraulic pressure is larger in the control to the closing side of the solenoid valve, and to set the gain to be smaller as the pre-change hydraulic pressure is larger in the control to the opening side. Good to do.

[0009]

The feedback correction means detects a state quantity such as the turbine speed at the time of gear shifting and outputs a control signal to the hydraulic control means so as to follow a predetermined target value. Control is performed. At this time, the value of the working oil pressure before the change is detected, and the detected value is
Gain control by the feedback correction means on the basis of the oil pressure changing direction determined from shifting state signal is changed, thus changing before based on hydraulics and the hydraulic change direction Gay
As a result, feedback control with good responsiveness is performed while ensuring stability.

Then, for example, the control of the operating oil pressure to the rising side is performed.
In control, the greater the pre-change hydraulic pressure, the greater the gain
Before the change in the control of the operating oil pressure to the descending side.
As the oil pressure increases, the gain decreases.

The hydraulic control means may include an electromagnetic valve for obtaining a control pressure by adjusting a drain amount of the original pressure. In this case, the electromagnetic valve moves to the closing side, that is, increases the hydraulic pressure. When the control is performed in the direction, the gain is set to be large, and when the control is performed to the opening side, that is, the direction in which the hydraulic pressure is reduced, the gain is set to be small.

[0012]

Embodiments will be described below with reference to the drawings.

FIG. 2 is an overall system diagram of one embodiment of the present invention. In this embodiment, an automatic transmission 2 connected to an engine 1 is a fluid type automatic transmission including a torque converter and an auxiliary transmission, and a hydraulic control circuit 3 for controlling the shift is provided with a lock-up Electromagnetic solenoid 4
And first, second, third, and third and fourth shift electromagnetic solenoids 5, 6, and 7, respectively. A control unit 8 for controlling these electromagnetic solenoids 4 to 7 is provided.
A throttle valve opening signal from a throttle sensor 10 attached to a throttle valve 9 of the engine 1 and a turbine speed signal from a turbine revolution sensor 11 attached to an output shaft of a torque converter of the automatic transmission 2 are input. Further, a pattern select signal from a pattern select switch 12 for changing the shift characteristic to either economy or power according to the driver's selection and a running mode signal from a running mode sensor (not shown) are input. Is input. The control unit 8 outputs a shift signal to each of the shift electromagnetic solenoids 5 to 7 according to a predetermined shift pattern based on these input signals, and outputs a lockup signal to the lockup electromagnetic solenoid 4.

FIG. 3 shows a hydraulic control circuit 3 of the automatic transmission 2.
Shows a part of. The hydraulic control circuit 3 has an oil pump 13 driven by an engine output shaft. The hydraulic oil discharged from the oil pump 13 to an oil passage 14 is reduced to a set oil pressure by a solenoid reducing valve 15. It is supplied to the duty solenoid 16 as the original pressure. This duty solenoid 1
Numeral 6 is for obtaining a control pressure by adjusting the drain amount of the original pressure. And the duty solenoid 16
Is amplified by the pressure modifier valve 17 and supplied as a pilot pressure of the pressure regulator valve 19 through the oil passage 18. The pressure regulator valve 19 regulates the oil pressure supplied to the oil passage 20 from the oil pump 13 by balancing the oil pressure from the oil passage 18.

In this embodiment, the feedback control of the hydraulic pressure supplied to the friction engagement element of the automatic transmission 2 during the gear shift is performed as follows. That is, when hydraulic pressure is supplied at the start of gear shifting, a change in turbine speed is detected by the turbine speed sensor 11 and is input to the control unit 8. Then, the turbine speed is compared with a preset target speed,
A signal is sent to the duty solenoid 16 according to the deviation to control the line pressure. Here, the relationship between the solenoid signal and the line pressure is as shown in FIG. In this figure, for a step-like solenoid signal,
The line pressure (P) is a curve that rises with a response delay as shown by the solid line. The response curve of the line pressure by such a duty solenoid can be approximated by a first-order lag model of a time constant T and a dead time L as shown by a broken line. Note that P ₍₀₎ indicates the hydraulic pressure (initial pressure) before the change.

Since the original pressure is supplied to the duty solenoid 16, the hydraulic response curve shows the hydraulic pressure P before the change.
High correlation with ₍₀₎ . That is, when the oil pressure rises as shown in FIG. 4, the oil pressure P ₍₀₎ before the change is plotted on the horizontal axis, and the time constant T and the dead time L are plotted on the vertical axis, respectively, as shown in FIGS. As shown in ₍₎₎ , the higher the value of P ₍₀₎ is, the smaller the values of T and L are. Therefore, as shown in FIG. 4C, the higher the _{value of} P _{(0), the} earlier the rise. On the other hand, at the time of shutdown, FIG.
The characteristics as shown in (a), (b), and (c) are obtained.
_{As (0)} increases, the values of T and L increase, and as P ₍₀₎ increases, the fall becomes slower.

Therefore, in the present embodiment, the gain amount of the feedback control is increased when the hydraulic response is high, and is decreased when the hydraulic response is low, that is, when the hydraulic pressure rises, the gain amount increases as P ₍₀₎ increases. When the hydraulic pressure is lowered, the gain is set to be smaller as P ₍₀₎ is higher.

Next, the flow for performing the above control is shown in FIG.
This will be described with reference to the flowchart of FIG.

When this flow is started by the input of a shift signal, first, the hydraulic pressure P ₍₀₎ before the change, that is, the line pressure set by the duty solenoid 16 before the shift is read.

Next, the gains G _U and G _D of the feedback control according to the oil pressure P ₍₀₎ are read, and the shift code K is set. Here, G _U, G _D is the gain for the fall and hydraulic raising respectively, as shown in FIG. 8 (a), (b) , set to a predetermined value in advance to P ₍₀₎ Have been. K is a code for determining whether the shift is an upshift or a downshift. In the case of an upshift, K =
In the case of 1, downshift, K = −1 is set.

Next, values such as the throttle opening (TVO), the engine speed and the turbine speed are read, and the base line pressure (P) during shifting is determined from these values by using a shifting line pressure map stored in advance. _B )
Set the line pressure.

When the shift is started, the turbine speed (N _T ) is read, and then the target turbine speed (N _T ) is read.
_T0 ) and calculate these deviations (ΔN _T ),
In order to determine whether the actual turbine rotation is higher or lower than the target turbine rotation, it is determined whether KΔN _T > 0. Here, the target turbine speed _NT0 is set so that its value gradually decreases after the input of the shift signal, as shown in FIG. 9, for example.

If the determination is YES, for example, at the time of an upshift (K = 1), as shown in FIG. 10, the actual turbine rotational speed _NT becomes the target turbine rotational speed N.
_Since it is larger than _T0 , the line pressure is controlled to increase the oil pressure. In that case, the gain G on the starting side
_U is used to calculate the rising line pressure (ΔP), and the rising amount ΔP is added to the baseline pressure P _B and set. On the other hand, if the above determination is NO, for example, at the time of downshifting (K = -1), as shown in FIG. 11, the actual turbine speed _NT is larger than the target turbine speed _NT0 . adopts the gain G _D of falling side calculates the [Delta] P (negative value), and controls the line pressure to reduce the oil pressure. The above processing is performed until the shift is completed.

[0024]

The present invention is configured as described above, so that an optimum gain corresponding to the hydraulic response can be set when the operating oil pressure of the automatic transmission is changed, whereby the stability and the response are improved. Feedback control can be realized.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is an overall system diagram of an embodiment of the present invention.

FIG. 3 is a hydraulic control circuit diagram of the embodiment.

FIG. 4 is a graph showing respective characteristics of a solenoid signal and a line pressure in the embodiment.

FIG. 5 is a graph showing a hydraulic response at the time of starting hydraulic pressure in the embodiment.

FIG. 6 is a graph showing hydraulic pressure response at the time of hydraulic pressure fall in the embodiment.

FIG. 7 is a flowchart for executing control of the embodiment.

FIG. 8 is a graph showing a relationship between a pre-change hydraulic pressure and a gain in the embodiment.

FIG. 9 is a graph showing a set value of a target turbine speed in the embodiment.

FIG. 10 is a graph showing a relationship between a change in turbine speed during an upshift and a target value in the embodiment.

FIG. 11 is a graph showing a relationship between a change in turbine rotation during a downshift and a target value in the embodiment.

[Explanation of symbols]

 2 Automatic transmission 3 Hydraulic control circuit 8 Control unit 16 Duty solenoid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] A hydraulic control means for controlling an operating oil pressure of the automatic transmission in accordance with a shift state signal; and a control amount of the operating oil pressure by the hydraulic control means being a predetermined value of a state amount related to a shift state of the automatic transmission. In a hydraulic pressure control device for an automatic transmission, comprising a feedback correction means for performing a feedback correction based on a deviation between a target amount and an actual amount, in a hydraulic pressure control apparatus for an automatic transmission, before detecting a value of an operating hydraulic pressure before a change when a shift state changes Hydraulic pressure detecting means, and a hydraulic pressure change determined from the pre-change hydraulic pressure detected by the pre-change hydraulic pressure detecting means and the shift state signal
A hydraulic control device for an automatic transmission, comprising: a gain changing unit that changes a gain of control by the feedback correction unit based on a direction . 2. The method according to claim 1, wherein the gain changing unit increases the operating oil pressure.
In the control to the side, the gain increases as the pre-change hydraulic pressure increases.
2. The automatic transmission according to claim 1, wherein
Hydraulic control device. 3. The system according to claim 2, wherein said gain changing means decreases said operating oil pressure.
In the control to the side, the gain decreases as the pre-change hydraulic pressure increases.
2. The automatic transmission according to claim 1, wherein
Hydraulic control device. 4. The system according to claim 1, wherein the hydraulic control means includes an electromagnetic valve that adjusts a drain amount of the original pressure to obtain a predetermined control pressure, and the gain changing means controls the closing of the electromagnetic valve. The larger the pre-change hydraulic pressure, the larger the gain is set.
2. The hydraulic control apparatus for an automatic transmission according to claim 1, wherein in the control to the opening side, the gain is set to be smaller as the pre-change hydraulic pressure is larger.