JPH1061532A - Step motor control method in idle speed control device - Google Patents

Abstract

(57) [Summary] A power transmission means having a backlash is provided between an idle adjustment valve and a step motor, and according to a current position determined by the number of operation pulses of the step motor from a reference position and an engine operation state. In the idle speed control device that controls the operation of the step motor with a pulse signal of the number of pulses corresponding to the difference from the determined target position, the opening degree of the idle adjustment valve is controlled with good responsiveness when restarting after shutting off the ignition switch In addition to the above, control at a low opening of the idle adjustment valve can be accurately and stably controlled. After the idle control valve resiliently biased to the closing side is driven to the fully closed position by the operation of the step motor immediately after the ignition switch is shut off, a pulse signal of a fixed number of pulses is given to the step motor to set the idle control valve. The valve is driven in the valve opening direction from the fully closed position to the set position, and the number of operation pulses of the step motor is reset so that the set position is determined as a reference position for idle speed control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor control method in an idle speed control device, and more particularly to a stepping motor having a backlash provided between an idle regulating valve and a stepping motor. An idle rotation speed control device in which the operation of the step motor is controlled by a pulse signal having a pulse number corresponding to a difference between the current position of the idle adjustment valve determined by the number of operation pulses and a target position determined according to the engine operating state. In the step motor control method.

[0002]

2. Description of the Related Art Conventionally, such a control method is known, for example, from Japanese Patent Publication No. 63-42106.

[0003]

The above publication makes it possible to easily associate the opening degree of the idle control valve with the number of operation pulses of the step motor without using a reference position sensor such as a potentiometer or a limit switch. Immediately after the ignition switch is shut off, a pulse signal of a fixed number of pulses is given to the step motor so as to drive the idle adjustment valve to the fully closed or fully opened position, and the step motor is set so that the fully closed or fully opened position is set as the reference position. The number of operation pulses is reset.

In the above publication, the idle adjusting valve is not resiliently biased toward the closing side, and the power transmission means provided between the idle adjusting valve and the step motor is constituted by a rack and a pinion. Since there is always a backlash between the rack and the pinion, during idling associated with engine restart, the operation of the step motor to the target position and the actual operating position of the idle adjustment valve associated with the operation of the step motor And a difference as shown in FIG.

That is, the backlash between the rack 21 and the pinion 22 and the excitation pattern in the step motor from when the idle adjusting valve V is fully closed as shown in FIG. (A maximum of three steps in a general four-pole two-phase excitation type step motor), the rack opening operation of the rack 21, that is, the idle adjustment valve V is started as shown in FIG. 10B. Therefore, the opening operation of the idle adjustment valve V is delayed by the time ΔT. FIG. 1 shows a state in which the idle adjustment valve V is in a position where it has been operated to a certain opening.
From the state of 0 (c) until the step motor operates in the valve closing direction by the operation amount ΔA ′, the closing operation of the rack 21, that is, the idle adjustment valve V is started as shown in FIG. However, the closing operation of the idle adjustment valve V is delayed by the time ΔT.

[0006] Further, in a motor having a return spring that urges the idle regulating valve toward the closing side, the idling of the step motor to the target position and the operation of the step motor during idling accompanying the restart of the engine. A difference as shown in FIG. 11 is generated between the idle adjustment valve and the actual operation position. That is, from when the idle adjusting valve is fully closed until the step motor operates by the operation amount ΔA ', the opening operation of the idle adjusting valve starts due to the backlash in the power transmission means and the deviation of the excitation pattern in the step motor. And the time Δ
After a delay of T occurs and the idle control valve operates to a certain opening, there is no time delay in the operation of the idle control valve, but the relationship always holds that target position> actual operation position.

As described above, in the system in which the idle control valve is driven to the fully closed position immediately after the ignition switch is shut off and the number of operation pulses of the step motor is reset so that the fully closed position is set as the reference position, the engine is restarted. Sometimes, regardless of the presence or absence of the return spring, the relationship of target position> actual operation position is established, and when the engine is restarted, the valve opening operation of the idle adjustment valve to the target opening degree is delayed. The opening of the idle adjustment valve becomes smaller than the target opening.

[0008] In the idle speed control, the idle adjustment valve is not fully closed, and fine adjustment is required in the vicinity of the fully closed state. Since the actual operation position differs between the valve opening drive and the valve closing drive of the idle adjustment valve, it is difficult to accurately control the idle rotation speed. In the case of a device having a return spring, the target position is always greater than the actual operating position.
The engine speed may become jerky and the idle speed may become unstable, leading to engine stall.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables the opening of the idle control valve to be controlled with good responsiveness at the time of restart after the ignition switch is cut off, and the idle control valve has a low opening. It is an object of the present invention to provide a stepping motor control method in an idle speed control device capable of accurately and stably controlling the control of the motor.

[0010]

In order to achieve the above object, an invention according to claim 1 includes an idle control valve for adjusting an opening degree of a passage for guiding intake air during idling; and a drive for opening and closing the idle control valve. A step motor that exerts force; power transmission means provided between the step motor and the idle control valve with backlash between a drive member on the step motor side and a driven member on the idle control valve side; The degree position is previously associated with the number of operation pulses of the step motor from the reference position, and the current position of the idle adjustment valve determined by the number of operation pulses of the step motor from the reference position is determined according to the engine operating state. A pulse signal of the number of pulses corresponding to the difference between the target position and the current position is output so as to match the target position. A control unit for controlling the operation of the step motor; and a step of driving the idle adjusting valve resiliently biased to the closing side to the fully closed position by operating the step motor immediately after the ignition switch is shut off. Providing a pulse signal of a fixed number of pulses to a step motor to drive the idle adjustment valve from a fully closed position to a set position in a valve opening direction so as to cause the drive member to operate more than a backlash in power transmission means; Resetting the number of operation pulses of the step motor to determine the position as a reference position for idle rotation speed control.

Immediately after the ignition switch is shut off, the idle control valve is driven to the fully closed position, and then the step motor is operated for more than the backlash to drive the idle control valve from the fully closed position to the set position to open the valve. By resetting the number of operation pulses of the step motor so as to determine the position as the reference position, when the engine is restarted, the actual operation position> the target position, and the idle adjustment valve can be promptly opened to the target opening degree, It is possible to obtain excellent startability. Moreover, the operation of the idle adjustment valve up to the required opening can be promptly performed even during the steady idling operation, and the engine rotation is smooth and there is no possibility of engine stall. In addition, since the idle control valve has the same opening regardless of the opening or closing operation direction, accurate control is possible by eliminating the possibility of uneven rotation or engine stall when controlling the idle control valve at a low opening. It is possible to do.
Furthermore, since the idle control valve is in the position slightly opened from the fully closed position in the ignition switch cutoff state, there is no danger of icing.

According to the second aspect of the present invention, after the reset of the number of operation pulses of the step motor is completed, the step motor is operated by the number of pulses corresponding to the outside air temperature, and the idle adjustment valve is moved from the reference position in the valve opening direction. By driving, by leaving the idle adjustment valve open to the opening degree according to the engine startability according to the outside air temperature,
Regardless of the change in the outside air temperature, the startability can be further improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 6 show a first embodiment of the present invention. FIG. 1 is a schematic sectional view showing the configuration of an idle rotation speed control device, and FIG. 2 is a vertical side view of an idle regulating valve and a step motor. FIG. 3 is a flowchart showing a control processing procedure of the step motor immediately after the ignition switch is cut off.
4 is a diagram showing changes in the step motor drive signal and the idle control valve operating position immediately after the ignition switch is shut off, FIG. 5 is a diagram sequentially showing the operating states of the idle control valve and the power transmission means from the fully closed position, and FIG. FIG. 7 is a diagram showing changes in the actual position and the target position of the idle adjustment valve after initialization.

Referring to FIG. 1, a throttle body 2 is provided at an intermediate portion of an intake passage 1 connecting an air cleaner AC and an engine E. The throttle body 2 is provided with a throttle for adjusting an opening degree of the intake passage 1. The valve 3 is rotatably disposed, and a passage 4 that bypasses the throttle valve 3 is provided. The passage 4 guides intake air for idling when the engine E is idling, and an idle adjustment valve V for adjusting the opening degree of the passage 4 to control the idling rotational speed is provided in the throttle body 2. .

Referring also to FIG. 2, idle control valve V
Is provided with a valve seat 6 formed in the middle of the passage 4 by forming a valve hole 5 connected to the upstream side 4a of the passage 4, and a valve body 7 that can be seated on the valve seat 6 from the downstream side 4b of the passage 4. The valve element 7 is connected to a step motor M mounted on the throttle body 2 via power transmission means 8.

The stepping motor M is well known in the art, and its structure will not be described in detail. However, a slight gap is provided between the rotor 10 having the permanent magnet 9 on the outer peripheral surface and the outer peripheral surface of the rotor 10. And a pair of stators 11 and 12 that are fixedly arranged with a space therebetween and are adjacent in the axial direction. The two stators 11 and 12 are provided in common in a cylindrical mold part 13 made of a synthetic resin.
Is rotatably supported by the mold portion 13 via a ball bearing 14 so as to prevent movement in the axial direction.

The power transmission means 8 is formed by screwing a valve shaft 15 as a driven member having one end fixed to the valve body 7 and a rotor 10 as a driving member on the step motor M side. That is, the male screw 16 provided on the valve shaft 15
A ridge 18 which is screwed into a screw hole 17 provided coaxially with the rotor 10 and protrudes from the outer surface of the valve shaft 15 along the axial direction thereof is provided in a guide groove provided in the mold portion 13. The fitting around 19 prevents rotation of the valve shaft 15 around the axis. Therefore, the valve shaft 15 operates in the axial direction according to the rotation of the step motor M,
This causes the idle control valve V to open and close. Moreover, between the valve body 7 and the mold part 13,
A coil-shaped return spring 20 is provided, and the spring force of the return spring 20 causes the idle adjustment valve V to move in the valve closing direction,
That is, the valve body 7 is urged in a direction for seating on the valve seat 6.

Referring again to FIG. 1, the operation of the step motor M is controlled by a control unit C. This control unit C controls the operation of the step motor M by open loop control until the complete explosion of the engine. After the complete explosion of the engine, the operation of the step motor M is controlled by feedback control so as to reach the target engine speed corresponding to the engine cooling water temperature. Thus, in the open loop control up to the complete explosion of the engine, the control unit C
The opening position of the idle adjustment valve V is previously associated with the number of operation pulses of the step motor M from the reference position, and the current position of the idle adjustment valve V determined by the number of operation pulses of the step motor M from the reference position is determined. A pulse signal having a pulse number corresponding to the difference between the target position and the current position is output so as to match a target position predetermined as an opening required for starting according to the engine operating state (specifically, engine cooling water temperature). To control the operation of the step motor M.

Immediately after the ignition switch is turned off, the control unit C controls the operation of the step motor according to the procedure shown in FIG. 3. In step S1, the number of repetitions N is set to "0", and in step S2 Then, it is checked whether or not the number of repetitions N is equal to or greater than a set number of times "N0". If N <N0, "1" is added to the number of repetitions N in step S3. The number of pulses MP is subtracted by “1”, and the process returns to step S2.

The set number "N0" is set to a value equal to or greater than the number of operating pulses of the step motor M for operating the idle adjustment valve V from the fully open position to the fully closed position. By the processing up to step S4, the idle adjustment valve V is driven to the fully closed position regardless of the position immediately after the ignition switch is shut off.

When N ≧ N0 in step S2,
That is, when the idle adjustment valve V is at the fully closed position, the number of operating pulses MP of the step motor M is added by "1" in step S5, and the number of operating pulses MP is equal to the predetermined number of pulses MP0 in step S6. It is determined whether or not MP <MP0, and the process returns to step S5.

Here, the predetermined number of pulses MP0 is a value sufficient to drive the stepping motor M so that the rotor 10 in the power transmission means 8 can operate more than the backlash in the power transmission means 8. S5, S
By the process of No. 6, the idle adjustment valve V is driven in the valve opening direction from the fully closed position to the set position.

In step S7 after the idle control valve V is opened to the set position, the number M of operation pulses of the step motor M is reset in order to determine the set position as a reference position for idle speed control. And initialize.

In the next step S8, the number of operating pulses MP of the step motor M is added by "1". In step S9, it is determined whether or not the number of operating pulses MP has become equal to the predetermined number of pulses MP1, and MP < If it is MP1, the process returns to step S8.

Therefore, after the reset of the operation pulse number of the step motor M is completed, the step motor M is operated by the predetermined pulse number MP1, and the idle adjustment valve V is driven from the reference position in the valve opening direction. In step S10, the power is turned off and the operation of the step motor M is stopped.

[0027] Such operation of the immediately following ignition switch-breaking step motor M and the idle regulating valve V is as shown in Figure 4, set in the closing direction the number from time t ₁ the engine is stopped the ignition switch is turned OFF By supplying drive signals to the step motor M by the number of pulses of “N0”, the idle adjustment valve V is completely closed at time t ₂ regardless of the position at which the ignition switch is turned off, the number of pulses MP0 only by the step motor M is actuated in the opening direction, the time t ₃
When the idle adjustment valve V is driven in the valve opening direction from the fully closed position to the set position, the number M of operation pulses of the step motor M is reset so as to determine the position as a reference position for idle speed control. Furthermore, from time t _3,
Predetermined number of pulses MP1 by the step motor M is actuated in the opening direction, when the idle regulating valve V is actuated to further opening direction from the reference position at time t _4, that actuation of the step motor M is stopped Become.

Here, the operation of the idle adjusting valve V from the fully closed position and the operating state of the power transmission means 8 at that time are as shown in FIG. 5, and the idle adjusting valve shown in FIG. Even when the step motor M is operated by the amount including the backlash δ of the power transmission means 8 and the deviation of the excitation pattern of the step motor M from the time when the valve V is fully closed, as shown in FIG. The idle adjustment valve V is in a fully closed state, and thereafter, when the step motor M is further operated to open the idle adjustment valve V to a certain opening, the operation pulse of the step motor M is set as a reference position of the idle adjustment valve V. The numbers will be reset.

Next, the operation of the first embodiment will be described. Immediately after the ignition switch is cut off, the idle adjusting valve V is driven to the fully closed position by the operation of the step motor M. More than rush rotor 1
0 to operate the idle adjustment valve V in the valve opening direction from the fully closed position to the set position, reset the number of operation pulses of the step motor M to determine the set position as a reference position for idle speed control, The step motor M is operated in the valve opening direction by a predetermined number of steps, and the idle adjustment valve V is further opened from the reference position in the valve opening direction.

After the initialization of resetting the number of operation pulses of the step motor M by such control processing, the operation of the step motor M up to the target position and the operation of the idle adjustment valve V accompanying the operation of the step motor M are performed. The actual operating position changes as shown in FIG.

That is, after the initialization, the actual operation position of the idle adjustment valve V is larger than the target position by the operation amount ΔA.
(The amount obtained by subtracting the backlash δ of the power transmission means 8 and the deviation of the excitation pattern in the step motor M from the total operation amount of the step motor M at the time of initialization), and delaying the operation of the step motor M to the target position. And the idle adjustment valve V opens and closes. Therefore, when the engine is restarted, the responsiveness can be improved by quickly operating the idle adjustment valve V to the target opening. In addition, even in the fine adjustment in the vicinity of the fully closed state, the actual operation position does not differ between the valve opening drive and the valve closing drive of the idle adjustment valve V, so that the idle rotation speed can be accurately controlled, and the actual operation position>
Since it is the target position, it is possible to avoid the jerking of the engine rotation speed, to enable stable idle rotation speed control, and to eliminate the possibility of engine stall as much as possible.

In addition, since the idle adjustment valve V is in a position slightly opened from the fully closed position in the ignition switch cutoff state, there is no risk of icing, and the idle adjustment valve V is further held open after initialization. Thus, the idle adjustment valve V can be quickly operated up to the target opening when the engine is restarted, and the startability is further improved.

Further, after the complete explosion of the engine, feedback control of the idle speed is performed so that the target engine speed corresponds to the temperature of the engine cooling water. Since the actual operating position is corrected to the position, no problem occurs.

FIGS. 7 and 8 show a second embodiment of the present invention. FIG. 7 is a flowchart showing a control processing procedure of the step motor immediately after the ignition switch is cut off, and FIG. 8 is an idle adjustment immediately after the ignition switch is cut off. It is a figure showing change of a valve operation position.

Immediately after the engine ignition switch is turned off, the operation of the step motor is controlled in accordance with the procedure shown in FIG. 7. Steps S11 to S17 are the same as those in the first embodiment shown in FIG. And step S
After resetting and initializing the operation pulse number M of the step motor M in step 17, in step S 18, it is determined whether or not the outside air temperature Tex is equal to or higher than a predetermined temperature Texo, for example, 10 ° C., and if Tex <Texo In step S19, the number of operation pulses M of the step motor M
P is incremented by "1", and it is determined in step S20 whether the number of operating pulses MP has become equal to the predetermined number of pulses MP1L. If MP <MP1L, step S1 is performed.
Return to 9.

Therefore, if Tex <Texo after the reset of the number of operation pulses of the step motor M is completed, the step motor M is operated by the predetermined number of pulses MP1L, and the idle adjustment valve V is moved from the reference position in the valve opening direction. Then, the power is turned off in step S23, and the operation of the step motor M is stopped.

When it is determined in step S18 that Tex ≧ Texo, in step S21, the number of operating pulses MP of the step motor M is incremented by "1".
In step S22, the operation pulse number MP is equal to the pulse number MP.
It is determined whether the number of pulses has become equal to the predetermined number of pulses MP1H smaller than 1L, and if MP <MP1H, the process returns to step S21.

Therefore, if Tex ≧ Texo after the reset of the operation pulse number of the step motor M is completed, the step motor M is operated by the predetermined pulse number MP1H, and the idle adjustment valve V is moved from the reference position in the valve opening direction. In step S23, the power is turned off.
As the FF, the operation of the step motor M is stopped.

According to the second embodiment, the idle control valve V is held at the position operated from the fully closed position to the valve opening side when the ignition switch is shut off. Further, as shown in FIG. Since the opening when the outside air temperature is low is made larger than the opening when the outside air temperature is high, the startability is further improved. That is, for example, when the outside air temperature is high in summer, the target opening at the start of the engine is relatively low, and when the outside air temperature is low in winter, the target opening at the start of the engine is relatively high. The startability can be improved by quickly operating the idle adjustment valve V to the target opening that changes according to the outside air temperature.

By the way, the target opening when starting the engine is
Specifically, the target opening is set according to the engine cooling water temperature.If the engine cooling water temperature is high even when the outside air temperature is low, the target opening is also low. The valve is returned to the valve closing direction, but the required opening degree at the start is sufficient, so that the startability is not impaired.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, the power transmission means 8 may be constituted by a rack and a pinion, and the opening degree of the idle adjustment valve V after initialization is set to three or more stages according to the outside air temperature. Is also good.

[0043]

As described above, according to the first aspect of the present invention, immediately after the ignition switch is turned off, the idle control valve is driven to the fully closed position, and then the step motor is operated more than the backlash to set the idle control valve. The idle control valve is driven to open to the target opening promptly by driving in the valve opening direction from the fully closed position to the set position, resetting the number of operation pulses of the step motor so as to determine the set position as the reference position. This makes it possible to obtain excellent startability, and at the same time during steady idling operation, the idle adjustment valve can be operated up to the required opening promptly, smoothing the engine rotation and reducing the occurrence of engine stall. It is possible to prevent the rotation of the idle control valve at the same opening regardless of the opening or closing operation direction. Prevents icing by maintaining the idle control valve slightly open from the fully closed position when the ignition switch is cut off be able to.

According to the second aspect of the present invention, after the reset of the number of operation pulses of the step motor is completed, the step motor is operated by the number of pulses corresponding to the outside air temperature, and the idle adjustment valve is moved from the reference position in the valve opening direction. By driving, the idle adjustment valve is kept open at an opening corresponding to the engine startability in accordance with the outside air temperature, and the startability can be further improved regardless of the change in the outside air temperature.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of an idle rotation speed control device according to a first embodiment.

FIG. 2 is a vertical sectional side view of an idle control valve and a step motor.

FIG. 3 is a flowchart showing a control processing procedure of a step motor immediately after an ignition switch is cut off.

FIG. 4 is a diagram showing changes in a step motor drive signal and an idle adjustment valve operating position immediately after an ignition switch is cut off.

FIG. 5 is a view sequentially showing an operation state of an idle adjustment valve and a power transmission means from a fully closed position.

FIG. 6 is a diagram showing changes in an actual position and a target position of an idle adjustment valve after initialization.

FIG. 7 is a flowchart illustrating a control processing procedure of the step motor immediately after the ignition switch is cut off in the second embodiment.

FIG. 8 is a diagram showing a change in an idle adjustment valve operating position immediately after the ignition switch is shut off.

FIG. 9 is a diagram showing changes in the actual position and the target position of the idle control valve after initialization in a conventional example having no return spring.

FIG. 10 is a view sequentially showing an operation state of the idle adjustment valve and the power transmission means from the fully closed position in a conventional example having no return spring.

FIG. 11 is a diagram showing changes in the actual position and the target position of the idle control valve after initialization in a conventional example having a return spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 4 ... Passage 8 ... Power transmission means 10 ... Rotor as a drive member 15 ... Valve shaft as a driven member C ... Control unit M ... Step motor V ... Idle adjustment valve

Claims (2)

[Claims] A passage for guiding intake air during idling (4)
Adjusting valve (V) for adjusting the opening of the motor; step motor (M) exhibiting a driving force for opening and closing the idle adjusting valve (V); driving member (10) on the step motor (M) side and idle The driven member (1) on the adjustment valve (V) side
5) a power transmission means (8) provided between the step motor (M) and the idle control valve (V) with a backlash therebetween; and the opening position of the idle control valve (V) from the reference position. The number of operation pulses of the step motor (M) is made to correspond in advance, and the current position of the idle adjustment valve (V) determined by the number of operation pulses of the step motor (M) from the reference position is determined according to the engine operating state. A control unit (C) for controlling the operation of the step motor (M) by outputting a pulse signal having a pulse number corresponding to the difference between the target position and the current position so as to match the target position. In the device, the idle control valve (V), which is urged toward the closing side, is driven to the fully closed position by the operation of the step motor (M) immediately after the ignition switch is shut off. -Up and the drive member (1
In order to make 0) operate more than the backlash in the power transmission means (8), a pulse signal of a fixed number of pulses is given to the step motor (M), and the idle adjustment valve (V) is opened from the fully closed position to the set position in the valve opening direction. A step of sequentially driving a step of driving and a step of resetting the number of operation pulses of the step motor (M) so as to determine the set position as a reference position for idle rotation speed control. Motor control method. 2. After the reset of the number of operation pulses of the step motor (M) is completed, the step motor (M) is operated by the number of pulses corresponding to the outside air temperature, and the idle control valve (V) is opened from the reference position in the valve opening direction. 2. A step motor control method in an idle speed control device according to claim 1, wherein