JP3423882B2 - Driving device for solenoid valve - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve drive device, and more particularly to a technique for improving the responsiveness of an actual current to a step change in a target current of the solenoid valve.

[0002]

2. Description of the Related Art Conventionally, a current actually flowing through a solenoid valve is detected, and a current control amount (for example, control duty) is feedback-controlled so that the actual current reaches a target value. There is known a solenoid valve drive device capable of controlling to a target current even if there are variations in temperature and power supply voltage (see Japanese Patent Laid-Open Nos. 3-199757 and 8-148333).

[0003]

By the way, JP-A-8-
As disclosed in Japanese Patent No. 291877, the solenoid valve has a characteristic that the current once decreases and then increases again in the process of increasing the current when the current supply to the coil is started. When the stepwise change becomes large, the drop in the process of increasing the current becomes larger, which is a factor that greatly impairs the responsiveness of the actual current to the target current.

For example, in an automatic transmission in which a hydraulic pressure is controlled by a solenoid valve to perform a gear shifting operation, if the responsiveness of the actual current to the target current is poor, a large deviation will occur between the target hydraulic pressure and the actual hydraulic pressure. This causes problems such as gear shift shock. The present invention has been made in view of the above problems, and an object of the present invention is to improve the responsiveness of an actual current to a stepwise change of a target current.

[0005]

Means for Solving the Problems] drive of the solenoid valve according to the invention of claim 1, wherein for this, and the target current setting means for setting a target current of the solenoid valve, the
Current detection means for detecting the actual current of the solenoid valve
And the current detected by the current detecting means is the target current setting.
So that it matches the target current set by the
Feedback control of energization control amount of renoid valve
Feedback control means and stepwise control of the target current
When the actual current is decreasing in response to a large increase
Then, the target current is increased and corrected, and the target current step
The actual current is increasing with respect to the decreasing
Sometimes, it comprises a correction means for reducing the target current .

According to such a configuration, the solenoid is required to know the correction request for causing the actual current to follow the change in the target current from the change direction of the target current and the change direction of the current actually flowing in the solenoid valve. Correct the target current of the valve. Specifically, for example, the target current increases in the increasing direction.
When the step changes, the actual current increases temporarily
If there is a decrease change in the
Corrections are made to increase the flow.

According to a second aspect of the present invention, the correction means has a higher absolute value as the absolute value of the change rate of the actual current is larger.
The target current is corrected with a correction value having a large logarithmic value .

According to this structure, the larger the rate of change of the actual current in the direction opposite to the direction of change of the target current is, the larger the correction of the target current is made so that there is no excess or deficiency in the change in the reverse direction. Apply correction.

[0009]

According to the invention of claim 1, the target current is
The actual current is changing in the direction corresponding to the changing direction of
It is possible to prevent the current from changing in the opposite direction on the way,
Therefore, the response of the actual current to the step change of the target current is
There is an effect that the response can be improved.

According to the second aspect of the invention, there is an effect that the current change in the direction opposite to the target current change direction can be effectively suppressed by appropriate correction.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 shows a hydraulic automatic transmission for a vehicle including a solenoid valve drive device according to the present invention. In FIG. 1, torque of an engine 1 mounted on a vehicle (not shown) is transmitted to drive wheels (not shown) via an automatic transmission 2.
The automatic transmission 2 may be either a continuously variable transmission or a stepped transmission.

Further, the control device 3 (in the drawing, denoted as A / TC / U) for controlling the shift of the automatic transmission 2 is
By incorporating a microcomputer including a CPU, a RAM, a ROM, etc., and controlling a plurality of solenoid valves that adjust hydraulic pressures for respective friction engagement elements (clutch, brake, etc.) of the automatic transmission 2, Automatically control the steps. The control device 3, together with the plurality of solenoid valves, is mounted as a unit in an ATF (automatic transmission fluid) atmosphere in an oil pan of the automatic transmission 2.

The solenoid valve changes the opening area of the oil passage by displacing the plunger (movable iron core) urged by the return spring by a magnetic force against the urging force of the return spring. The control device 3 determines the target hydraulic pressure and controls the hydraulic pressure supplied to each frictional engagement element based on the correlation between the drive current i applied to the solenoid valve and the hydraulic pressure. The drive current i corresponding to the target hydraulic pressure is obtained as the target current and output to the solenoid valve, and
The energization control amount of the solenoid valve (for example, the on-duty of the transistor) is feedback-controlled so that the current actually flowing through the solenoid valve matches the target current.

Specifically, with the configuration shown in FIG. 2, the energization of the solenoid valves is individually feedback-controlled. In FIG. 2, a target current calculation unit 51 (target current setting means) calculates a target current corresponding to the target hydraulic pressure at that time from the correlation between the target hydraulic pressure and the drive current stored in advance.

A response correction unit 59 (correction means) for correcting the actual response delay of the current of the solenoid valve with respect to the step change of the target current is provided, and the target calculated by the target current calculation unit 51 is provided. The electric current is corrected based on the correction amount set by the response correction unit 59. The response correction unit 59 will be described in detail later.

On the other hand, since there is a deviation between the instruction value required to actually obtain the target current and the target current due to variations in individual solenoid valves, the correction amount setting unit 58
Stores a correction amount corresponding to the deviation for each target current in advance, and outputs the correction amount corresponding to the target current corrected by the response correction unit 59. And the response correction unit
The addition result of the target current corrected by 59 and the correction amount set by the correction amount setting unit 58 is output to the median value setting unit 52 as the final target current.

The median value setting unit 52 sets a reference duty (median value) corresponding to the target current and outputs it as a feedforward amount (F / F correction amount) (control means). On the other hand, the feedback correction unit 53 obtains a deviation between the detected value of the current actually flowing in the solenoid valve 5 and the target current corrected by the response correction unit 59, and proportional, integral, derivative (PID) based on the deviation. output feedback frequency of (F / B correction amount) by the control operation (Fi
Feedback control means) .

Then, the feed forward (F / F
The result (duty) obtained by adding the correction amount) and the feedback amount (F / B correction amount) is output to a transistor (not shown) that controls the amount of electricity supplied to the solenoid valve 5, and the transistor responds to the duty according to the duty. By performing the on / off control, the energization amount of the solenoid valve 5 is controlled according to the on time ratio.

The current detection of the solenoid valve 5 is output as a terminal voltage of a resistor provided for current detection (current detection means), and the voltage is input to an A / D converter 56 via a low pass filter 55. A / D converted. A /
The voltage data after D conversion is converted into current data by the voltage-current converter 57. Then, the detected data of the current is subtracted from the target current corrected by the response correction unit 59, and the deviation obtained by the subtraction processing is output to the feedback correction unit 53 as an error amount.

Here, the correction amount set by the correction amount setting unit 58 is subtracted from the output of the voltage-current converter 57, and the detection result after the subtraction correction is calculated by the target current calculation unit 51. An error amount (control deviation) is calculated as a deviation from the target current. Next, the response correction unit 59
Will be described in detail.

The response correction unit 59 is the voltage-current converter.
The change rate Δi of the actual current i obtained by subtracting the correction amount set by the correction amount setting unit 58 from the output of 57 is calculated, while the change direction of the target current calculated by the target current calculation unit 51 is calculated. And the correction amount of the target current is determined from the change rate Δi and the changing direction of the target current. For example, when the target current increases stepwise and the current flowing through the solenoid valve 5 increases, the self-induced electromotive force generated by the movement of the plunger causes the current to temporarily decrease, as shown in FIG. This temporary decrease of the current causes a delay in the response of the actual current to the step change of the target current. On the contrary, when the target current decreases stepwise, the current temporarily increases during the actual decrease process of the current,
There is a delay in response to a decrease in the target current. When the plunger has a fixing failure, the current does not change in the direction opposite to the direction in which the target current changes.

Therefore, the response correction unit 59 calculates the change rate Δi of the actual current, and when the target current increases, for example, stepwise, the actual current is decreased in the opposite direction to the increasing direction. Changes (when the rate of change Δi becomes negative), as shown in FIG. 4, the larger the absolute value of the rate of change Δi, the larger the correction value is set. On the other hand, when the target current decreases, for example, stepwise, when the actual current changes in the increasing direction which is the opposite direction to the decreasing direction (when the change rate Δi becomes positive),
As shown in FIG. 5, the larger the absolute value of the change rate Δi is, the larger the absolute value of the negative correction amount is set.

That is, when the current changes in a direction different from the original change direction, in order to suppress the current change in the opposite direction, the target current is increased and corrected for the decrease. The target current is reduced and corrected with respect to the change in the direction, so that the current change in the direction opposite to the direction of the change in the target current is reduced, and the actual current response to the step change in the target current is reduced. Improve sex.

In addition, in parallel with the correction of the target current for improving the responsiveness, a structure for diagnosing the sticking failure of the plunger based on whether or not a current change in the direction opposite to the direction of change of the target current has occurred. Is also good.

Further, in the above-mentioned embodiment, the solenoid valve used for hydraulic pressure adjustment in the automatic transmission is described, but it may be a solenoid valve used for flow rate adjustment, and an applicable device is an automatic transmission. It is not limited.

[Brief description of drawings]

FIG. 1 is a diagram showing an automatic transmission for a vehicle including a solenoid valve drive device according to the present invention.

FIG. 2 is a block diagram showing a solenoid valve drive device according to an embodiment.

FIG. 3 is a time chart showing characteristics of actual current change with respect to stepwise change of target current.

FIG. 4 is a diagram showing a characteristic of a correction current with respect to an increase change of a target current in the embodiment.

FIG. 5 is a diagram showing a characteristic of a correction current with respect to a decrease change of a target current in the embodiment.

[Explanation of symbols] 1 engine 2 automatic transmission 3 control device 5 solenoid 51 Target current calculator 52 Median setting section 53 Feedback correction section 55 Low-pass filter 56 A / D converter 57 Voltage-current converter 58 Correction amount setting section 59 Response compensator

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16K 31/06 H01F 7/18

Claims (2)

(57) [Claims] 1. A target current setting means for setting a target current of a solenoid valve, and a current detection for detecting an actual current of the solenoid valve.
Means and the current detected by the current detecting means is the target current setting means.
The solenoid current to match the target current set by the stage.
Feedback control of the energization control amount of the id valve.
The feedback control means and the actual power supply for the stepwise increase change of the target current.
When the current is decreasing, the target current is increased.
However, when the target current decreases stepwise,
The target current is decreased when the current of the
A solenoid valve drive device comprising: a correction unit that corrects the pressure. 2. The rate of change of the actual current is corrected by the correction means.
The larger the absolute value of, the larger the correction value
Drive of the solenoid valve according to claim 1, wherein the correcting the target current.