JPH11223262A - Hydraulic controller for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control by hydraulic pressure supplied to a friction engaging element to a target pressure even if there is dispersion or aging in solenoid. SOLUTION: A hydraulic switch is provided for outputting a detecting signal when the supply pressure of a friction engaging element reaches a set pressure, and when the detecting signal is outputted from the hydraulic witch (S1), a driving current (i) for a solenoid at this time is read (S2). Then, deviation Δi between a driving current (is) corresponding to a set pressure in a basic characteristic and the read driving current (i) is set as a correction value for the driving current (i) when the set pressure is a target oil pressure (S3). Then, correction values in all of the control ranges of the target oil pressure are calculated by interpolation operation based on the correction value Δi (S4), the driving current (i) set based on the target oil pressure is corrected by a corresponding correction value and outputted to the solenoid (S8).

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, and more particularly, to an automatic transmission for a vehicle configured to control engagement and release of a friction engagement element by hydraulic pressure.

[0002]

2. Description of the Related Art Conventionally, a target value of a hydraulic pressure supplied to a friction engagement element such as a clutch or a brake is converted into a control amount (drive current) of a solenoid, and the solenoid is controlled based on the control amount to control the friction. 2. Description of the Related Art There is known an automatic transmission for a vehicle configured to control a supply hydraulic pressure to a combined element to the target value.

[0003]

However, even if a control amount corresponding to the target oil pressure is given to the solenoid due to the characteristic variation of the solenoid or a change with time, the actual supply oil pressure may deviate from the target value. There was a possibility of causing a shift shock or the like. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a hydraulic control device for an automatic transmission that can accurately control a target hydraulic pressure with a simple configuration even if there are variations in characteristics of the solenoid or changes with time. And

[0004]

According to the first aspect of the present invention, there is provided a hydraulic control apparatus for an automatic transmission configured to perform a shift operation by controlling a supply hydraulic pressure to a friction engagement element to a target hydraulic pressure by a solenoid. A hydraulic switch for outputting a detection signal when a supply oil pressure to the friction engagement element reaches a set pressure, and for obtaining the set pressure from a control state of a solenoid when the detection signal is output from the hydraulic switch. Learn the control amount of the solenoid, and
The control amount is corrected for each target oil pressure by an interpolation calculation based on the learned control amount.

According to this configuration, when the detection signal is output from the hydraulic switch and it is detected that the actual supply pressure to the friction engagement element is equal to the set pressure of the hydraulic switch, the detection signal corresponding to the set pressure is set. The amount of solenoid control to be performed is learned, and the learning result is reflected on other target hydraulic pressures by interpolation. A second aspect of the present invention is a hydraulic control device for an automatic transmission configured to perform a shift operation by controlling a supply hydraulic pressure to a friction engagement element to a target hydraulic pressure by a solenoid, and is configured as shown in FIG. You.

In FIG. 1, target hydraulic pressure setting means sets the target hydraulic pressure, and solenoid control means outputs a control amount to the solenoid according to the target hydraulic pressure. On the other hand, the hydraulic switch outputs a detection signal when the supply hydraulic pressure to the friction engagement element has reached a set pressure, and the correction means has the target hydraulic pressure and / or the output pressure when the detection signal is output from the hydraulic switch. Alternatively, the control characteristic of the solenoid control means is corrected based on the control amount.

According to this configuration, when the detection signal is output from the hydraulic switch and it is detected that the actual supply pressure to the friction engagement element is equal to the set pressure of the hydraulic switch, the control amount at that time is used. It is detected that the set pressure is obtained, and the deviation between the target oil pressure and the set pressure at that time is detected as a hydraulic control error. Based on these, the correlation between the target oil pressure and the control amount ( Correct the solenoid control characteristics).

According to the third aspect of the present invention, the correction means corrects a control amount for obtaining the set pressure from the target oil pressure and / or the control amount when the detection signal is output from the hydraulic switch. Is obtained, and a correction value for each target hydraulic pressure is obtained by an interpolation operation based on the learned correction value,
The control value of the solenoid is corrected and set by the correction value.

According to this configuration, when the correction value for correcting the basic value of the control amount corresponding to the set pressure is learned at the time of outputting the detection signal of the hydraulic switch, the correction request for the set pressure is set to the target other hydraulic pressure. In order to reflect this, a correction value for each target oil pressure is obtained by interpolation, and the basic value is corrected with the correction value to control the solenoid. According to a fourth aspect of the present invention, the hydraulic switch includes a plurality of hydraulic switches that output detection signals at different set pressures.

According to this configuration, the control amount (correction value) for correctly obtaining the target hydraulic pressure at a plurality of different hydraulic pressures.
Are obtained for the respective cases, and in the case of performing the interpolation calculation, the correction values at the other target hydraulic pressures are calculated using the plurality of points as the reference points. According to the fifth aspect of the present invention, the set pressure at which the hydraulic switch outputs the detection signal is set to a value that divides the control range of the target hydraulic pressure substantially equally.

According to this configuration, the hydraulic pressure (set pressure) at which the hydraulic switch outputs the detection signal is substantially evenly distributed in the hydraulic control range, and the correction request at the substantially evenly distributed hydraulic pressure is used as a reference in all regions. A correction value will be estimated.

[0012]

According to the first aspect of the invention, the correlation between the target oil pressure and the control amount is corrected based on the control amount for obtaining the set pressure detected by the hydraulic switch. Even with such a configuration, the target hydraulic pressure can be correctly controlled with a simple configuration, and thus there is an effect that the occurrence of a shift shock or the like due to a shift in the supply hydraulic pressure to the friction engagement element can be avoided.

According to the second aspect of the present invention, a variation in hydraulic pressure with respect to the control amount or a control amount for obtaining the set pressure is learned based on the target hydraulic pressure and the control amount at the set pressure detected by the hydraulic switch. Since the control characteristics are corrected, the target hydraulic pressure can be correctly controlled with a simple configuration even if the solenoid varies or changes over time, thereby preventing the occurrence of a shift shock due to a shift in the supplied hydraulic pressure to the friction engagement element. This has the effect.

According to the third aspect of the invention, the correction value for each target hydraulic pressure is interpolated based on the correction request at the set pressure, and the basic control value is corrected with the correction value for each target hydraulic pressure. Thus, there is an effect that the target hydraulic pressure can be accurately controlled. According to the fourth aspect of the invention, by detecting a correction request at a plurality of hydraulic pressures using a plurality of hydraulic switches, the accuracy of interpolation calculation is improved, and a correction value corresponding to a target hydraulic pressure at which a correction request is not directly detected. There is an effect that can be set with high accuracy.

According to the fifth aspect of the present invention, by dispersing the points at which the actual oil pressure detection is performed substantially evenly within the control range, the interpolation operation can be performed with high accuracy over the entire area.

[0016]

Embodiments of the present invention will be described below. FIG. 2 shows an automatic transmission to which the hydraulic control device according to the present invention is applied. 2, a torque of an engine 1 mounted on a vehicle (not shown) is transmitted to driving wheels (not shown) via an automatic transmission 2. The automatic transmission 2 may be either a continuously variable transmission or a stepped transmission.

Further, a control device 3 (in the figure, denoted by A / TC / U) for performing a shift control of the automatic transmission 2 includes:
By incorporating a microcomputer including a CPU, a RAM, a ROM, and the like, and controlling a plurality of solenoids for adjusting the hydraulic pressure for each friction engagement element (clutch, brake, etc.) of the automatic transmission 2, Automatically controls the gear.

As shown in FIG. 3, for example, the solenoid adjusts a hydraulic pressure supplied to a friction engagement element (clutch or the like) 30 of the automatic transmission 2 by a drain of the original pressure. The plunger (movable iron core) 32 urged by the return spring 31 is displaced up and down in the figure by the magnetic force of the electromagnetic coil 33 against the urging force of the return spring 31 to reduce the opening area of the drain passage 34. It is configured to change.

The control device 3 determines a target hydraulic pressure for each solenoid, and sets a drive current i to be applied to the solenoid.
A drive current i corresponding to the target oil pressure is obtained based on a correlation between the (control amount) and the oil pressure, and the drive current of each solenoid is individually controlled. Here, as shown in FIG. 3, a hydraulic switch 35 for outputting a detection signal when the hydraulic pressure supplied to the friction engagement element 30 reaches a set pressure.
The control device 3 learns a correction value of the drive current i based on a detection signal from the hydraulic switch 35, and uses the learned correction value to control the drive current i.
Is corrected and output to the solenoid 36.

More specifically, the driving current i is corrected as shown in the flowchart of FIG. In the flowchart of FIG. 4, first in S1, the hydraulic switch 35
It is determined whether or not a detection signal has been output from. The hydraulic switch 35 is set so that its output signal switches on and off at a substantially central value (set pressure) of the control range of the target hydraulic pressure, and the switching of the output signal on and off is used as a detection signal. The determination is made in S1.

At S1, the output signal of the hydraulic switch 35 is turned on.
When it is detected that the state has been switched from OFF to OFF or from OFF to ON, the process proceeds to S2, and the drive current i (or target oil pressure) for the solenoid 36 at that time is read. In the next S3, a drive current is corresponding to a set pressure at which the detection signal of the hydraulic switch 35 is output is obtained from a basic correlation, and a deviation Δi between the drive current is and the drive current i read in S2 is obtained. Is calculated as the correction value of the drive current i corresponding to the set pressure at which the detection signal of the hydraulic switch 35 is output.

That is, the output of the detection signal of the hydraulic switch 35 indicates that the drive current i at that time has actually been adjusted to the set pressure of the hydraulic switch 35, and The drive current i to be output when the set pressure is set to the target pressure is learned, and the drive current is corresponding to the set pressure and the value corresponding to the set pressure are determined based on the basic correlation. The deviation Δi from the learned drive current i is a correction value of the drive current i required when the set pressure is set as the target pressure.

In other words, if there is no deviation in the basic correlation, the hydraulic switch 35 outputs a detection signal when the set pressure of the hydraulic switch 35 is set as the target hydraulic pressure. In this case, the drive current is corresponding to the set pressure obtained from the basic correlation should match the drive current i read in S2, and the difference between the set pressure and the target oil pressure at that time is , The deviation of the hydraulic pressure obtained with respect to the drive current i at that time, and the difference between the drive current i at that time and the drive current is corresponding to the set pressure obtained from the basic correlation is the set pressure Shows the shift of the drive current i that should be handled.

Therefore, based on the difference between the set pressure and the target oil pressure when the set pressure is detected, a correction value Δ corresponding to the set pressure is determined.
It is also possible to calculate i. When the correction value for setting the set pressure of the hydraulic switch 35 to the target oil pressure is obtained as described above, in S4, a correction value corresponding to the target oil pressure other than the set pressure is obtained, for example, by linear interpolation.

Specifically, assuming that the correction request at the minimum target oil pressure is 0, an interpolation calculation is performed so that the correction value gradually increases as the pressure approaches the set pressure from the minimum target oil pressure and reaches the aforementioned Δi. The correction request at the maximum target pressure is set to 0, and the interpolation calculation is performed so that the correction value gradually decreases from the correction value Δi of the set pressure and becomes 0 at the maximum target pressure. That is, the correction value obtained by the interpolation calculation is interpolated so that the set pressure of the hydraulic switch 35 (the middle value of the oil pressure range) becomes a peak and the value gradually becomes smaller as the target oil pressure approaches the maximum or the minimum. Therefore, as shown by the dotted line in S3, particularly when there is a larger correction request near the center of the hydraulic control range, the correction value of the entire region can be accurately estimated by the interpolation calculation using the detection result of the hydraulic switch 35.

In S5, the target hydraulic pressure of the friction engagement element 30 is determined (target hydraulic pressure setting means). In the next S6, the basic correlation between the target hydraulic pressure and the drive current i is referred to to determine the target hydraulic pressure at that time. A drive current i corresponding to the oil pressure is obtained. In S7, it is determined whether or not the correction value has been learned. If the correction value has been learned, the process proceeds to S8. In S8, a correction value corresponding to the target oil pressure at that time is obtained, added to the drive current i obtained in S6 and corrected, and the corrected drive current i is output to the solenoid 36 (solenoid control means).

The functions of S1 to S4 and S8 correspond to the correction means. On the other hand, if it has not been learned, the process proceeds to S9,
The drive current i obtained in S6 is output to the solenoid 36 as it is. In the above embodiment, the set pressure at which the hydraulic switch 35 outputs the detection signal is set near the center value of the hydraulic control range. However, there is a region in the hydraulic control range where particularly high-precision hydraulic control is required. In such a case, the set pressure at which the hydraulic switch 35 outputs the detection signal may be set to a biased value within the hydraulic control range so that the detection signal is output with the oil pressure within that region.

In the above embodiment, the hydraulic switch
Although only one solenoid 35 is provided for each solenoid 36,
A plurality of hydraulic switches 35 that output detection signals in response to different set pressures in the same hydraulic path may be provided. For example, when two hydraulic switches 35 are provided,
As shown in FIG. 5, each hydraulic switch 35 is set so that the hydraulic control range is divided into approximately three equal parts by the set pressure of the hydraulic switch 35.
It is good to set the set pressure.

In particular, as shown in FIG. 6, when the correction request is such that the median value of the hydraulic pressure tends to switch between minus and plus, the hydraulic control range becomes approximately three or more depending on the set pressure of each switch. If they are separated, it is possible to ensure interpolation accuracy. Therefore, if it is known in advance that the correction request has a certain tendency, the number of hydraulic switches 35 and the set pressure for outputting the detection signal may be set in accordance with the characteristics of the correction request.

As the hydraulic switch 35, a switch set for fail-safe use can be used.
By sharing 35, cost increase can be avoided. In the above description, the interpolation calculation is linear interpolation, but it is clear that curve interpolation may be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of the invention according to claim 2;

FIG. 2 is a diagram showing an automatic transmission according to the embodiment.

FIG. 3 is a diagram showing a hydraulic control system according to the embodiment in detail.

FIG. 4 is a flowchart showing a state of solenoid control in the embodiment.

FIG. 5 is a diagram illustrating correction characteristics when two hydraulic switches are used.

FIG. 6 is a diagram showing another example of a correction characteristic when two hydraulic switches are used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Control device 30 Friction engagement element 31 Return spring 32 Plunger 33 Electromagnetic coil 34 Drain passage 35 Hydraulic switch 36 Solenoid

Claims (5)

[Claims] 1. A hydraulic control device for an automatic transmission configured to perform a shift operation by controlling a supply oil pressure to a friction engagement element to a target oil pressure by a solenoid, wherein the supply oil pressure to the friction engagement element becomes a set pressure. A hydraulic switch for outputting a detection signal when the detection signal is output from the hydraulic switch, learning a control amount of a solenoid for obtaining the set pressure from a control state of the solenoid at the time of outputting the detection signal from the hydraulic switch, and A hydraulic control device for an automatic transmission, wherein the control variable is corrected for each target hydraulic pressure by an interpolation calculation based on the controlled variable. 2. A hydraulic pressure control device for an automatic transmission configured to perform a shift operation by controlling a supply hydraulic pressure to a friction engagement element to a target hydraulic pressure by a solenoid, wherein target hydraulic pressure setting means for setting the target hydraulic pressure, Solenoid control means for outputting a control amount to the solenoid in accordance with a target oil pressure, a hydraulic switch for outputting a detection signal when a supply oil pressure for the friction engagement element reaches a set pressure, and a detection signal from the hydraulic switch And a correcting means for correcting a control characteristic of the solenoid control means based on the target hydraulic pressure and / or the control amount at the time of output of the automatic transmission. 3. The correction means learns a correction value of a control amount for obtaining the set pressure from the target oil pressure and / or the control amount at the time of outputting a detection signal from the hydraulic switch. 3. The hydraulic control device for an automatic transmission according to claim 2, wherein a correction value for each target hydraulic pressure is obtained by interpolation calculation based on the corrected correction value, and the control amount of the solenoid is corrected and set based on the correction value. 4. The hydraulic control device for an automatic transmission according to claim 1, wherein the hydraulic switch includes a plurality of hydraulic switches that output detection signals at different set pressures. . 5. The system according to claim 1, wherein the set pressure at which the hydraulic switch outputs a detection signal is set to a value that divides the control range of the target hydraulic pressure substantially equally. A hydraulic control device for an automatic transmission according to claim 1.