JPH09324869A - Driving current controlling method for linear solenoid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output stable hydraulic pressure with high response to the target output oil pressure value of a linear solenoid, by suppressing current change at one time of the driving current of the linear solenoid in a range where surge may not be generated in output oil pressure by the linear solenoid, and restricting the inclination of the driving current. SOLUTION: Firstly, an oil pressure command value is set. Next, it is judged whether an absolute value (step) command or a sweep command (S2). In the case of the absolute value (step) command, a maximum time constant 60msec calculatedly and experimentally tuned is set (S3). Next, current step width (A) = target current value - present current command value, therefore it is set to current amount changed at one time (1.6msec)=(1.6msec/time constant 60msec) (S4). Hereat, the current value changed at one time (1.6msec) can be suppressed, and the inclination of current is restricted. Next, the current value is set (S8).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive current control method for a linear solenoid, and more particularly to a drive current control method for a linear solenoid used for hydraulic control of an automatic transmission mounted on a vehicle.

[0002]

2. Description of the Related Art When an electronic control unit (ECU) determines a gear shift in a hydraulic control of an automatic transmission mounted on a vehicle (for example, piston stroke control of a hydraulic servo during a gear shift), the ECU causes a linear solenoid to operate. In contrast, a drive current is supplied, and the output pressure of the linear solenoid is used to achieve the gear shift stage.However, conventionally, the drive current value of a linear solenoid is controlled in vertical steps. ing.

FIG. 6 is a diagram showing the relationship between the line pressure and the drive current value of the linear solenoid in such shift control.
6A shows the input rotation speed of the transmission, FIG. 6B shows the line pressure, and FIG. 6C shows the drive current value of the linear solenoid. In this way, by changing the drive current value of the linear solenoid, the line pressure is controlled to control the input rotation speed of the transmission.

[0004]

However, since the drive current of the conventional linear solenoid described above is vertical step control, a surge occurs in the output hydraulic pressure due to the inertial force due to the weight of the spool valve of the linear solenoid. As a result, the responsiveness and stability with respect to the target output hydraulic pressure value are lacking, which may lead to a shift shock.

For example, in the case of the portion A in FIG. 6, when the drive current value a of the linear solenoid is increased in vertical steps as shown in FIG. 7, a surge occurs in the hydraulic pressure b by the linear solenoid. Therefore, the present invention solves the above-mentioned problems, and provides a drive current control method for a linear solenoid that can output a stable hydraulic pressure in a fast response to the target output hydraulic pressure value of the linear solenoid. To aim.

[0006]

In order to achieve the above object, the present invention provides [1] a command current value to a linear solenoid set according to a vehicle traveling state and a current actually applied to the linear solenoid. In a drive current control method of a linear solenoid that feedback-controls an output voltage value based on a difference from a monitored feedback current value, when the drive current of the linear solenoid is increased or decreased to a predetermined target current value, the linear solenoid The current amount of the drive current of the linear solenoid that is changed once is suppressed within a range in which a surge does not occur in the output hydraulic pressure, and the inclination of the drive current is limited.

[2] In the drive current control method for a linear solenoid according to the above [1], the slope of the drive current is a sweep step. [3] In the method for controlling a drive current of a linear solenoid according to the above [1], it is a step in which the slope of the drive current is expressed by a first-order lag equation. As described above, in order to output a stable hydraulic pressure value with a high-speed response to the target hydraulic pressure value, the current of the linear solenoid is not step-controlled, but the high-speed sweep control is performed. As shown, the amount of current that drives the linear solenoid to change once is suppressed,
The slope of the drive current can be limited.

The sweep time constant is calculated and experimentally tuned according to the valve weight of the linear solenoid, the valve sleeve clearance, the valve sleeve material, and the spring constant. Further, the same effect can be obtained not by the fast sweep but by the steps represented by the first-order delay equation as shown in FIG.

[0009]

According to the present invention, since the gradient of the drive current of the linear solenoid can be limited to the range in which the output hydraulic pressure of the linear solenoid does not generate a surge, the linear solenoid is set to the target output hydraulic pressure value. It is possible to output a stable hydraulic pressure with high speed response.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a drive current control device for a linear solenoid showing an embodiment of the present invention. In FIG. 1, 1 is an oil temperature sensor, 2 is a vehicle speed sensor,
3 is a throttle opening sensor, 4 is a linear solenoid, 5
Is a pressure regulating mechanism, 6 is a modulator valve arranged in a line pressure (PL) system, 7 is a clutch, and 8 is a pressure regulating valve for adjusting the hydraulic pressure supplied to the clutch.

Reference numeral 10 denotes an electronic control unit, which is connected to the oil temperature sensor 1, the vehicle speed sensor 2, and the throttle opening sensor 3 respectively.
1, a hydraulic pressure / current conversion unit 12 connected to the clutch hydraulic pressure calculation unit 11, a current comparison unit 13 connected to the hydraulic pressure / current conversion unit 12, and a PI connected to the current comparison unit 13.
The control unit 14, the PWM output unit 15 connected to the PI control unit 14, and the solenoid drive circuit 18 connected to the PWM output unit 15 are provided, and the output of the solenoid drive circuit 18 is supplied to the linear solenoid 4. A solenoid current monitor circuit 19 is connected to the linear solenoid 4, an AD value / current converter 20 is connected to the solenoid current monitor circuit 19, and the AD value / current converter 20 is connected to the AD value / current converter 20.
Is output to the current comparison unit 13.

Further, in the present invention, the outputs of the oil pressure / current conversion unit 12, the current comparison unit 13 and the PI control unit 14 are connected to the resistance value calculation / comparison / correction unit 16, and the resistance value calculation / comparison / comparison The correction unit 16 can exchange data with the storage device 17, and the data in the storage device 17 is stored in the PI control unit 14.
Can be read. Therefore, a linear voltage feedback control of the output voltage value is performed based on the difference between the command current value to the linear solenoid 4 set according to the vehicle traveling state and the feedback current value obtained by monitoring the current value actually applied to the linear solenoid 4. In the method for controlling the drive current of the solenoid 4, when the drive current of the linear solenoid 4 is raised or lowered to a predetermined target current value, the drive current of the linear solenoid 4 is set within a range in which a surge does not occur in the output hydraulic pressure of the linear solenoid 4. The current amount to be changed once is suppressed, and the gradient of the drive current is limited.

A specific method of controlling the drive current of the linear solenoid will be described below with reference to FIG. FIG. 2 is a flowchart of the drive current control of the linear solenoid showing the embodiment of the present invention. (1) First, the hydraulic pressure command value is set (step S
1).

(2) Next, it is determined whether it is an absolute value (step) command or a sweep command (step S2). (3) In step S2, in the case of an absolute value (step) command, a maximum time constant of 60 msec calculated and experimentally tuned is set (step S3).

(4) Next, current step width (A) = target current value-current current command value, which is once (1.6
The current amount to be changed to (msec) = (1.6 msec / time constant 60 msec) is set (step S4). Here, as shown in FIG. 3, the current value changed once (1.6 msec) is suppressed, and the slope of the current is limited.

(5) In step S2, in the case of the sweep command, it is determined whether the time constant is 60 msec or less (step S5). (6) If YES in step S5, the maximum time constant 60 msec is set (step S6), and the process proceeds to step S4. (7) In step S5, in the case of NO, current step width (A) = target current value−current current command value, and current amount changed once (1.6 msec) =
Set to (1.6 msec / time constant x) (step S
7) and proceeds to step S8.

(8) Next, the current value is set (step S8). Since the control is performed as in the above embodiment, for example, in the portion A in FIG. 6, the drive current value of the linear solenoid and the hydraulic pressure by the linear solenoid are controlled as shown in FIG. In this figure, a is the drive current value of the linear solenoid, b is the hydraulic pressure by the linear solenoid, and it is understood that the hydraulic pressure by the linear solenoid can output a stable hydraulic pressure without becoming a surge.

In the above description, the case where the drive current of the linear solenoid in FIG. 6 is increased to a predetermined target current value has been described. However, when the drive current of the linear solenoid in FIG. 6 is decreased to a predetermined target current value, That is,
By similarly controlling the drive current of the linear solenoid in the A'section, the inclination of the drive current of the linear solenoid can be limited to the range in which the output hydraulic pressure of the linear solenoid does not generate a surge. It is possible to output a stable hydraulic pressure with a high-speed response to the target output hydraulic pressure value.

In the above embodiment, the absolute value command or the sweep command having a small inclination has been described, but instead of this, a step represented by a first-order lag equation as shown in FIG. 5, that is, a corner is rounded. The same effect can be obtained by the steps. Further, the present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a drive current control device for a linear solenoid showing an embodiment of the present invention.

FIG. 2 is a drive current control flowchart of a linear solenoid showing an embodiment of the present invention.

FIG. 3 is a diagram showing a change amount per time of a drive current of the linear solenoid showing the embodiment of the present invention.

FIG. 4 is a diagram showing a drive current value of a linear solenoid and a hydraulic pressure by the linear solenoid according to the drive current control of the linear solenoid of the present invention.

FIG. 5 is a diagram showing an example of control by steps represented by a first-order lag type of drive current of the linear solenoid of the present invention.

FIG. 6 is a diagram showing a relationship between a line pressure and a drive current value of a linear solenoid in shift control.

FIG. 7 is a diagram showing a change in line pressure due to drive current control of a conventional linear solenoid.

[Explanation of symbols]

 1 Oil temperature sensor 2 Vehicle speed sensor 3 Throttle opening sensor 4 Linear solenoid 5 Pressure regulating mechanism 6 Modulator valve 7 Clutch 8 Pressure regulating valve 10 Electronic control unit 11 Clutch hydraulic pressure calculation unit 12 Hydraulic pressure / current conversion unit 13 Current comparison unit 14 PI control Part 15 PWM output part 16 Resistance value calculation / comparison / correction part 17 Storage device 18 Solenoid drive circuit 19 Solenoid current monitor circuit 20 AD value / current conversion part

Claims (3)

[Claims] 1. An output voltage value is feedback-controlled based on a difference between a command current value to a linear solenoid set according to a vehicle traveling state and a feedback current value obtained by monitoring a current value actually applied to the linear solenoid. In the method for controlling the drive current of the linear solenoid, when the drive current of the linear solenoid is raised or lowered to a predetermined target current value, the drive current of the linear solenoid is set once when the surge is not generated in the output hydraulic pressure of the linear solenoid. A method for controlling a drive current of a linear solenoid, characterized in that the amount of current to be changed to 1 is suppressed and the inclination of the drive current is limited. 2. The drive current control method for a linear solenoid according to claim 1, wherein the slope of the drive current is a sweep step. 3. The drive current control method for a linear solenoid according to claim 1, wherein the step of expressing the slope of the drive current by a first-order lag equation.