JP2000064886A - Idling air quantity control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control the idling air quantity with a full opening position as a reference position without precision machining even with dispersion in the full opening position by operating a step motor until a switch detects an idle adjusting valve to have reached the opening limit after reaching the closing limit. SOLUTION: At the time of connecting a new battery B due to replacement of a battery B, the pulse number corresponding to operation from a total closure limit to full opening limit of an idle adjusting valve V is determined and stored regardless of product-by-product dispersion. At the time of initialization processing, the idle adjusting valve V is driven to the opening limit, and the operating pulse number of a step motor upon reaching the valve opening limit is reset by the stored determined pulse number so as to be able to accurately set a reference position determined as the valve opening limit every initialization processing. At the time of initialization processing, the idle adjusting valve V has only to be driven to the valve opening limit regardless of the opening position of the idle adjusting valve V.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle control valve that adjusts the opening of a passage that guides intake air during idling; a step motor that exerts a driving force for opening and closing the idle control valve; and an opening of the idle control valve. The position is made to correspond in advance to the operation pulse number of the step motor from the reference position, and the current position of the idle control valve determined by the operation pulse number of the step motor from the reference position is a target determined according to the engine operating state. A control unit for controlling the operation of the step motor by outputting a pulse signal of a pulse number corresponding to the difference between the target position and the current position so as to match the position, and an idle air amount control device.

[0002]

2. Description of the Related Art Conventionally, such an idle air amount control device is known from, for example, Japanese Patent Publication No. 63-42106.

[0003]

SUMMARY OF THE INVENTION In the above conventional one,
In order to easily associate the opening 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 limit switch, the idle control valve can be fully closed or fully open. Immediately after turning off the ignition switch, etc., a pulse signal with a fixed number of pulses is applied to the step motor to drive the motor, and the number of operating pulses of the step motor is reset so that the fully closed or fully opened position becomes the reference position. I am trying to do it.

By the way, in the case where the fully closed position of the idle control valve is set as the reference position, if the initialization process is carried out when the engine is started or when the vehicle is running, the valve body will be driven to the fully closed limit. There is a problem that the number of revolutions decreases, and it takes time to drive up to the fully closed limit depending on the opening position of the idle control valve during the initialization process, which may delay the initialization process.

On the other hand, when the fully open position of the idle control valve is set as the reference position, the engine speed does not decrease during the initialization process, and further, depending on the opening position of the idle control valve during the initialization process. It is possible to quickly drive to the limit and perform the initialization process quickly. However, the fully closed position of the idle control valve does not vary from product to product,
Due to the accumulation of machining tolerances and assembly errors, there will be variations in the fully open position for each product.To minimize such variation, it is necessary to perform adjustment finishing while detecting the stroke of the valve disc for each product. Therefore, it is not realistic in terms of processing man-hours and costs. Therefore, in reality, the fully open position of the idle control valve is set as the reference position in preparation for variations, which makes it difficult to control the idle air amount accurately and precisely.

The present invention has been made in view of the above circumstances, and takes advantage of the advantage of using the fully open position as the reference position without performing precision machining even if the fully open position varies from product to product. It is an object of the present invention to provide an idle air amount control device which enables accurate and precise control of the idle air amount.

[0007]

In order to achieve the above object, the invention according to claim 1 is an idle control valve for adjusting the opening 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 a force; an idle determined in advance by making the opening position of the idle control valve correspond to the number of operation pulses of the step motor from the reference position, and determined by the number of operation pulses of the step motor from the reference position. A control unit for controlling the operation of the step motor by outputting a pulse signal of a pulse number corresponding to the difference between the target position and the current position so as to match the current position of the control valve with the target position determined according to the engine operating state; The idle air amount control device including: a switch for detecting that the opening position of the idle control valve is at the valve opening limit. It includes a pitch, the control unit,
When a new battery is connected, the stepping motor is operated until the opening position of the idle control valve is once set as the closing limit, and then at least the switch detects the opening limit. To the number of pulses corresponding to the operation from the valve opening limit is determined and stored as the number of operation pulses corresponding to the reference position,
During the initialization process that makes the opening position of the idle control valve correspond to the number of operation pulses of the step motor from its reference position, until the switch detects that the opening position of the idle control valve has reached the opening limit. The number of operating pulses of the step motor when the step motor is operated is reset by the determined and stored number of pulses, and the opening position of the idle control valve at the time of reset is set to the reference position.

With such a configuration, the step motor is operated until the switch detects that the open limit has been reached after the idle control valve has been set to the closed limit, regardless of product-to-product variations. It is possible to determine the number of pulses corresponding to the operation of the idle control valve from the fully closed limit to the fully open limit, and when the battery is newly connected by replacing the battery, the pulse number is determined and stored. Will be. On the other hand, during the initialization processing, the step motor is operated until the opening position of the idle control valve reaches the valve opening limit, and the number of operating pulses of the step motor when the valve opening limit is reached with the stored fixed number of pulses is set. By resetting, it is possible to correctly set the reference position defined as the valve opening limit for each initialization process. Therefore, even if there is product-to-product variation in the fully open position, it is not necessary to perform precision machining to minimize the variation, and
It enables precise control of the idle air amount. Moreover, at the time of initialization processing, it is not necessary to temporarily set the opening position of the idle control valve to the closing limit, and it is sufficient to drive the idle control valve to the opening limit regardless of the opening position of the idle control valve. The processing time can be shortened.

The invention according to claim 2 is the above-mentioned claim 1.
In addition to the features of the described invention, the switch is configured to conduct when the valve body of the idle control valve moves to its open limit, and the control unit controls the new connection of the battery and the initialization process. Occasionally, the step motor is operated so as to drive the valve element to the valve opening side until the switch becomes conductive, and then the step motor is operated in the reverse direction, and the time when the switch changes from the conductive state to the cutoff state It is characterized in that it is determined as the timing for determining the number of pulses and the reset timing.

According to the configuration of the invention as set forth in claim 2, the timing at which the switch changes from the conductive state to the cutoff state is set as the reference position. That is,
Regardless of the operation of the step motor, the number of operating pulses of the step motor is reset at the moment when the valve element moves from the valve opening limit to the valve closing side, so all variations of each product are absorbed and the reference position is not estimated. You can actually confirm. At this time, if the valve body of the idle control valve is urged toward the closing side by the spring, the excitation pattern of the step motor shifts when the step motor operates in the reverse direction from the valve opening direction to the valve closing direction. The step motor operates for the amount of time, and the number of operating pulses of the step motor will be reset at the moment when the valve body starts to move from the valve opening limit, and if the valve body is not spring biased to the closing side, the step At the moment when the step motor operates by the operation amount including the backlash of the power transmission means between the motor and the valve body and the deviation of the excitation pattern of the step motor and the valve body starts to move from the valve opening limit, Will be reset.

Further, in addition to the structure of the invention according to claim 1, the invention according to claim 3 is characterized in that the control unit drives the idle control valve when the battery is newly connected and when initialization processing is performed. The operation frequency of the step motor is controlled by making the drive frequency of the step motor smaller than that at the time of executing the idle air amount control by adjusting the opening degree of the idle control valve.

By the way, when the idle control valve is driven to the valve closing limit and the valve opening limit, a phenomenon in which the number of steps of the step motor jumps due to the magnetic pole structure of the step motor, a so-called bounceback phenomenon occurs, and the idle control The valve may move from its closing limit and opening limit, and with such a bounceback phenomenon occurring, the number of operating pulses of the step motor at the reference position,
The opening position of the idle control valve cannot be correctly matched. However, when the inventor measured the occurrence of the bounceback phenomenon by changing the driving voltage and the driving frequency, the result as shown in FIG. 7 was obtained. Based on the result shown in FIG. 7, Below a certain driving frequency FT, the bounceback phenomenon does not occur regardless of the driving voltage. Therefore, according to the third aspect of the present invention, the drive frequency at the time of executing the normal idle air amount control by adjusting the opening degree of the idle control valve is set to the constant drive frequency F.
By setting the drive frequency to be larger than T and setting the drive frequency for driving the idle control valve at the time of new connection and initialization of the battery to be equal to or lower than the constant drive frequency FT, the control speed during normal control is increased and the responsiveness is improved. Improve
It is possible to prevent the bounceback phenomenon from occurring at the time of newly connecting the battery and at the time of initializing, so that the operating pulse number of the step motor and the opening position of the idle control valve can be more correctly associated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is a schematic sectional view showing the structure of an idle air amount control device, and FIG. 2 is a vertical sectional side view of an idle control valve and a step motor. FIG. 3 is a flowchart showing a procedure for determining the operation pulse number at the reference position, which is executed when a battery is newly connected, and FIG. 4 is a diagram showing changes in the step motor drive signal and the operation pulse number during the operation pulse number confirmation processing. 5 is a flowchart showing the control processing procedure of the step motor at the time of initialization, FIG. 6 is a diagram showing changes in the step motor drive signal and the number of operation pulses at the time of initialization, and FIG. It is a graph which shows the measured result.

First, in FIG. 1, a throttle body 2 is provided in an intermediate portion of an intake passage 1 connecting between an air cleaner AC and an engine E. The throttle body 2 is provided with a throttle body 2 for adjusting an opening of the intake passage 1. The valve 3 is rotatably arranged, and a passage 4 that bypasses the throttle valve 3 is provided. The passage 4 guides idle intake air when the engine E is idling, and an idle control valve V for adjusting the opening of the passage 4 to control the amount of idle air is provided in the throttle body 2. .

Referring also to FIG. 2, the idle control valve V
Includes 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 body 7 is connected to a step motor M attached to the throttle body 2 via a power transmission means 8.

The step motor M is well known in the art and its structure will not be described in detail. However, a small gap is provided between the rotor 10 having the permanent magnet 9 on the outer peripheral surface thereof and the outer peripheral surface of the rotor 10. And a pair of stators 11 and 12 that are fixedly disposed with a space therebetween and that are adjacent in the axial direction. Both the stators 11 and 12 are commonly provided in a cylindrical mold portion 13 made of synthetic resin, and
Is rotatably supported by the mold portion 13 via a ball bearing 14 so as to be prevented from moving in the axial direction.

The power transmission means 8 is formed by screwing a valve shaft 15 having one end fixed to the valve body 7 and a rotor 10 on the step motor M side. That is, the male screw 16 provided on the valve shaft 15 is screwed into the screw hole 17 provided coaxially on the rotor 10, and the ridge 18 projected on the outer surface of the valve shaft 15 along its axial direction. By being fitted into the guide groove 19 provided in the mold portion 13,
Rotation around the axis of the valve shaft 15 is prevented. Therefore, the valve shaft 15 is actuated in the axial direction according to the rotation of the step motor M, which causes the idle control valve V to be opened and closed. In addition, a coil-shaped return spring 20 is provided between the valve body 7 and the mold portion 13, and the spring force of the return spring 20 causes the idle control valve V to close the valve, that is, the valve body 7 to the valve seat. 6 will be urged in the direction to be seated.

The idle control valve V is provided with a switch 21 which conducts when the valve body 7 reaches the valve opening limit, and the switch 21 connects the valve body 7 of the mold portion 13 of the step motor M to the valve body 7. A fixed contact 23 provided at the opposite end and a ring-shaped movable contact 25 fixed to the valve body 7.
And the fixed contact 23 comprises a pair of contact pieces 22 ₁ and 22 ₂ which simultaneously come into contact with the movable contact 25 according to the movement of the valve body 7 to the valve opening limit.
Conductors 26 and 27 are connected to 2 ₁ and 22 ₂ , respectively.

The operation of the step motor M is controlled by the control unit C to which the battery B is connected. The control unit C controls the operation of the step motor M by open loop control until the engine complete explosion. However, after the complete explosion of the engine, the operation of the step motor M is controlled by feedback control so that the target engine speed is set according to the engine cooling water temperature. Thus, in the open loop control until the engine complete explosion, the control unit C associates the opening position of the idle control valve V with the number of operation pulses of the step motor M from the reference position in advance, and controls the opening position from the reference position. In order to match the current position of the idle control valve V, which is determined by the number of operation pulses of the step motor M, with a target position that is predetermined as an opening required for starting according to the engine operating state (specifically, engine cooling water temperature), the target position And, the operation of the step motor M is controlled by outputting a pulse signal having a pulse number corresponding to the difference between the current positions.

Further, the control unit C is supplied with a signal indicating conduction / interruption of the switch 21 from both conducting wires 26 and 27. The control unit C performs the process of determining the number of operation pulses of the step motor M at the reference position defined as the valve opening limit of the idle control valve V by replacing the battery B by replacement or the like.
Switch 21 at the time of new connection to the control unit C of
In addition to executing the initializing process based on the signal from the, the initializing process for making the operation pulse number of the step motor M and the opening position of the idle control valve V correspond, for example, immediately after the ignition switch is cut off (immediately after the engine is stopped) or the ignition switch Immediately after the electrical connection is made (immediately after the engine is started), it is executed based on the signal from the switch 21.

When the process of determining the number of operation pulses at the reference position is performed when the battery B is newly connected to the control unit C, the control unit C controls the operation of the step motor M according to the procedure shown in FIG.

In step S1 of FIG. 3, the number of repetitions N is set to "0", and in step S2 it is confirmed whether the number of repetitions N is equal to or more than the set number "N1", and N <
If it is N1, "1" is added to the number of repetitions N in step S3, the operation pulse number MP of the step motor M is subtracted by "1" in step S4, and the process returns to step S2.

The set number of times "N1" is set to a value equal to or greater than the number of operating pulses of the step motor M for driving the valve body 7 of the idle control valve V from the fully open limit to the fully closed limit. , Step S1 to Step S4
By the processing up to, even if the valve body 7 is in any position,
The valve body 7 is driven to the fully closed position.

When N ≧ N1 in step S2, it means that the valve body 7 has been driven to the fully closed limit, so that the process proceeds from step S2 to step S5. Number MP is "0"
Specified in. That is, the number of operating pulses of the step motor M is reset to "0" when the valve body 7 is at the fully closed limit. Then, in step S6, the step motor M
By adding "1" to the operation pulse number MP of, the step motor M drives the valve body 7 in the reverse direction, that is, in the valve opening direction after driving to the fully closed limit. Further, in step S7, it is determined whether or not the switch 21 has changed from the OFF (cutoff) state to the ON (conduction) state for a certain time ΔT, and the switch 21 does not change the switching mode from the OFF state to the ON state. , And OF
If the constant time ΔT does not elapse even if the switching mode is changed from the F state to the ON state, step S7
Then, the process returns to step S6 and "1" is added to the operation pulse number MP of the step motor M.

By the processes of steps S5 to S7, it is possible to reliably detect that the opening position of the idle control valve V has changed from the fully closed limit to the fully open limit.

At step S7, the switch 21 is turned off.
When it is confirmed that a certain time ΔT has passed from the FF state to the ON state, that is, when it is detected that the valve body 7 has certainly reached the valve opening limit, in step S8, the operation pulse of the step motor M The number MP is subtracted by "1". As a result, the step motor M drives the valve body 7 to the valve closing side. In step S9, it is confirmed whether or not the switch 21 has changed from the ON state to the OFF state, and if it remains in the ON state, the process proceeds to step S8. return,
Further, when it is confirmed that the switching mode of the switch 21 has changed from the ON state to the OFF state, in step S10, the idle control valve V whose operation pulse number MP of the step motor M at that time is set as the valve opening limit is set.
Confirmed as the number of confirmed pulses MP0 corresponding to the reference position of
Remember.

That is, by the processing of steps S8 to S10, the step motor M is operated so as to drive the valve body 7 at the valve opening limit to the valve closing side, and when the switch 21 changes from the ON state to the OFF state, the step is performed. The number of operating pulses of the motor M is determined and stored as the number of determined pulses MP0 corresponding to the reference position.

Further, in step S11, the operating pulse number MP of the step motor M is decremented by "1", and in step S12, the operating pulse number MP is the predetermined pulse number M.
Until it is confirmed that P1 has been reached, the number of operating pulses MP
Is subtracted by "1".

Therefore, after the determined pulse number MPO corresponding to the reference position is determined and stored, the step motor M is operated toward the valve closing side by the predetermined pulse number MP1 to drive the idle control valve V from the reference position in the valve closing direction. Will be done.

The operation of the step motor M when the battery B is newly connected is as shown in FIG. 4, and the set number of times is "N1" in the valve closing direction from the time t ₁ when the battery B is newly connected. By supplying the drive signal to the step motor M by the number of pulses, the idle control valve V
At the time t ₂ when the battery B is newly connected, the limit value is surely reached to the fully closed limit at time t ₂ , and then the switch 21 is turned off in response to the step motor M being operated in the valve opening direction. Time t _{3 when the} state changes to the ON state
From time t ₄ when a fixed time ΔT has elapsed from the step, the step motor M is operated in the valve opening direction. Thus, when the switching mode is changed from the ON state to the OFF state at time t ₅ after the step motor M starts operating in the valve opening direction, the valve body 7 is set to the reference position which is the fully open position. As a result, the operating pulse number of the step motor M is determined and stored as the determined pulse number MP0.

Further, from time t ₅ , a predetermined pulse number M
The step motor M is operated in the valve closing direction until reaching P1, and when the idle control valve V further operates in the valve closing direction from the reference position until time t ₆ , the step motor M is operated.
Will stop working.

Further, when performing the operation pulse number of the step motor M and the idle control valve initialization processing, the control unit C controls the operation of the step motor M according to the procedure shown in FIG.

In step S21 of FIG. 5, the number of repetitions N is set to "0", and in step S22, the number of repetitions N is set.
Check whether the number of times exceeds the set number "N1"
If <N1, then the number of repetitions N in step S23
To the operation pulse number MP of the step motor M in step S24, and in step S25, the switch 21 changes from the OFF state to the ON state for a certain time ΔT. When the switch 21 does not change the switching mode from the OFF state to the ON state and when the switching mode does not change from the OFF state to the ON state but the predetermined time ΔT does not elapse, it is determined from step S25. It returns to step S22.

Further, when it is confirmed in step S22 that N ≧ N1 is satisfied, or when it is confirmed in step S25 that the switch 21 has been changed from the OFF state to the ON state and a certain time ΔT has passed, the step is executed. The process proceeds to S26.

According to the processes of steps S21 to S25, the valve body 7 of the idle control valve V can be reliably driven to the fully open limit regardless of the position of the valve body 7 at the start of its operation. become.

In step S26, the operation pulse number MP of the step motor M is subtracted by "1". As a result, the step motor M drives the valve body 7 to the valve closing side. In step S27, it is confirmed whether or not the switch 21 has changed from the ON state to the OFF state, and if it remains in the ON state, the process proceeds to step S26. Return and O from the ON state
When it is confirmed that the switching mode of the switch 21 has changed to the FF state, in step S28, the operation pulse number of the step motor M at that time is confirmed and reset by the stored confirmed pulse number MP0.

That is, by the processing of steps S26 to S28, the step motor M is operated so as to drive the valve body 7 at the valve opening limit to the valve closing side, and when the switch 21 changes from the ON state to the OFF state, the step is performed. The number of operation pulses of the motor M is set as the number of operation pulses corresponding to the reference position, and the fixed pulse number MP0 is reset.

Further, in step S29, the operation pulse number MP of the step motor M is subtracted by "1", and in step S30 the operation pulse number MP is the predetermined pulse number M.
Until it is confirmed that P1 has been reached, the number of operating pulses MP
Is subtracted by "1".

Therefore, after the operation pulse number corresponding to the reference position is reset, the step motor M is operated to the valve closing side by the predetermined pulse number MP1 so that the idle control valve V is driven in the valve closing direction from the reference position. become.

The operation of the step motor M at the time of initialization is as shown in FIG. 6, and the step motor M is operated in the valve opening direction from time t _{11 when the} engine is stopped by turning off the ignition switch. ,
Regardless of the position of the idle control valve V when the ignition switch is cut off, the idle control valve V is surely at the fully open limit at time t ₁₂ before reaching the set pulse number N1, and thereafter, for a fixed time ΔT.
After the lapse of time, the step motor M is operated to set the position at time t _{13 when} the switch 21 is changed from the ON state to the OFF state in response to the step motor M being operated in the valve opening direction as the reference position for the idle air amount control. The number of pulses is reset. From further time t _13, the step motor M to reach a predetermined number of pulses MP1 is actuated in the closing direction, when the idle regulating valve V is actuated to further closing direction from the reference position to the time t _14, step The operation of the motor M will be stopped.

When the control unit C drives the valve body 7 of the idle control valve V when the battery B is newly connected and when the initialization process is performed, the step motor M is used.
Drive frequency is set lower than that during execution of idle air amount control by adjusting the opening of the idle control valve V.

By the way, when the idle control valve V is driven to either the valve closing limit or the valve opening limit, the phenomenon that the step number of the step motor M jumps due to the magnetic pole structure of the step motor M, so-called bounce back. A phenomenon may occur and the idle control valve V may move from its closed limit or open limit. This bounce back phenomenon occurs when the step motor M is operated so as to drive the idle control valve V to either the valve closing limit or the valve opening limit, and the rotor 1 is driven when the stepping motor M has a specific excitation magnetic pole.
Due to the structure of the step motor M, the behavior in which 0 rotates in the reverse rotation direction and tries to stabilize is caused.
Occurs when the rotor 10 has a sufficient inertial force at the time of reverse rotation and the reverse rotation timing matches the drive frequency.

Even when the determination process and the initialization process of the number of operation pulses corresponding to the reference position are performed in the state where such a bounceback phenomenon occurs, the number of operation pulses of the step motor M and the opening degree of the idle control valve V are set. It is not possible to correctly correspond to the position.

However, when the present inventor measured the occurrence of the bounceback phenomenon by changing the driving voltage and the driving frequency, the results shown in FIG. 7 were obtained, and the results shown in FIG. 7 were obtained. Based on this, it is understood that the bounceback phenomenon does not occur regardless of the drive voltage at a constant drive frequency FT (for example, 150 PPS) or less.
Therefore, the drive frequency at the time of executing the normal auxiliary air amount control by adjusting the opening degree of the idle control valve V is set to be higher than the constant drive frequency FT, and the idle adjustment is performed at the time of finalizing the operation pulse number corresponding to the reference position and at the time of initialization. By setting the drive frequency for driving the valve body 7 of the valve V to be equal to or lower than the constant drive frequency FT, the control speed during normal control is increased to improve the responsiveness, and the bounceback phenomenon is not generated during initialization. Can be prevented.
Therefore, the number of operation pulses of the step motor M and the opening position of the idle control valve V can be more correctly corresponded at the time of the determination processing and the initialization processing of the operation pulse number corresponding to the reference position.

Next, the operation of this embodiment will be described. When a new connection is made to the control unit C by replacing the battery B or the like, the control unit C sets the idle control valve V to the valve closing limit and then to the valve opening limit. Switch 21 that reached
The step motor M is operated until it is detected by the above, whereby the operation pulse number of the step motor M corresponding to the operation from the fully closed limit to the fully open limit of the idle control valve V can be determined, and the fully open valve can be determined. The number of actuating pulses at the reference position defined on the side can be determined regardless of the product-to-product variation.

On the other hand, during initialization processing immediately after the ignition switch is cut off, the step motor M is operated until the opening position of the idle control valve V reaches the valve opening limit, and the valve opening limit is reached by the stored number of fixed pulses. By resetting the number of operating pulses of the step motor M when it becomes, it is possible to correctly set the reference position defined as the valve opening limit for each initialization process. Therefore, even if there is a product-to-product variation in the fully open position, it is not necessary to perform precision machining to minimize the variation, and accurate and precise control of the idle air amount becomes possible. Moreover, at the time of the initialization processing, it is not necessary to temporarily set the opening position of the idle control valve V to the valve closing limit, and the idle control valve V may be driven to the valve opening limit regardless of the opening position of the idle control valve V. Therefore, the initialization processing time can be shortened.

Moreover, at the timing for determining the number of operation pulses at the reference position and the reset timing at the time of initialization, the idle control valve V is driven to the fully open limit by the operation of the step motor M, and then the step motor M is operated.
Switch 21 in the opposite direction
It is determined when the N state changes to the OFF state. As a result, the number of operating pulses of the step motor M is reset at the moment when the excitation pattern of the step motor M shifts and the step motor M operates by the backlash of the power transmission means 8 and the valve body 7 starts to move from the valve opening limit. Therefore, it is possible to absorb all the variations of each product and actually determine the reference position instead of estimating it.

Further, since the valve body 7 is biased toward the closing side by the return spring 20 and the backlash of the power transmission means 8 is absorbed, the actual operating position of the idle control valve V becomes the target position after the initialization. Since they coincide with each other, the idle control valve V is opened and closed without delaying the operation of the step motor M up to the target position. Therefore, the responsiveness can be improved by promptly operating the idle control valve V to the target opening when the engine is restarted. Moreover, even in the fine adjustment near the fully closed position, the actual operating position does not differ between the valve opening drive and the valve closing drive of the idle control valve V, so that the accurate idle air amount control can be performed.

Further, since the idle control valve V is in the open position when the ignition switch is shut off, there is no risk of icing. By further maintaining the idle control valve V open after initialization, the engine is restarted. The idle control valve V can be promptly operated up to the target opening, and the startability is further improved.

Further, since the switch 21 detects the valve body 7 at the open limit of the idle control valve V, it is not necessary to adjust the mounting position of the switch 21, and the switch 21 has a simple structure with a reduced number of parts. Is possible and wiring is easy.

Moreover, the switch 21 comprises a movable contact 25 that operates together with the valve body 7, and a fixed contact 23 that contacts the movable contact 25 at the valve opening limit of the valve body 7.
A pair of contact pieces 22 that are individually connected to the conductors 26 and 27
Since it is composed of ₁ and 22 ₂ , the movable contact 25
It is not necessary to connect a conducting wire to the side, and the wiring connection configuration of the switch 21 becomes simple.

When the valve body 7 is made of synthetic resin, it is easy to ensure the insulation of the movable contact 25.

In the above embodiment, the timing for executing the initialization process is set immediately after the ignition switch is cut off.
The timing of executing the initialization process is not limited to immediately after the ignition switch is cut off, and the initialization process may be performed immediately after the engine is stopped, after the engine is started, or while the vehicle is running.

The present invention can also be applied to the idle adjusting valve V in which the valve body 7 is not biased toward the valve closing side. In that case, the backlash of the power transmission means between the step motor and the valve body is increased. The step motor operates by an operation amount including the amount of deviation of the excitation pattern of the step motor, and the number of operation pulses of the step motor is reset at the moment when the valve body starts to move from the valve opening limit.

Further, when the process of determining the number of operation pulses of the reference position defined on the fully open side is executed at the time of newly connecting to the control unit C by replacing the battery B or the like, the idle control valve V is set to the closing limit. In this state, the Sato pulse number of the step motor M is reset to "0" (step S in FIG. 3).
5) However, even if it is not reset to "0" at the valve closing limit, the difference between the number of operating pulses at the valve closing limit and the number of operating pulses at the valve opening limit is calculated to calculate the number of operating pulses at the valve open position. May be determined.

Although the embodiments of the present invention have been described in detail above, 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 claims. It is possible to do.

[0058]

As described above, according to the first aspect of the present invention, when the battery is newly connected by replacing the battery or the like, the idle control valve from the fully closed limit to the fully open limit regardless of product variations. The number of pulses corresponding to the operation up to is determined and stored, and during the initialization process, the idle control valve is driven until it reaches the opening limit, and the step motor when the stored number of defined pulses reaches the opening limit. By resetting the number of operation pulses of, it is possible to correctly set the reference position defined as the valve opening limit for each initialization process. Therefore, even if the fully open position varies from product to product, it is not necessary to perform precision machining, and accurate and precise control of the idle air amount becomes possible. Moreover, during the initialization process, the idle control valve can be driven up to the valve opening limit regardless of the opening position of the idle control valve, so that the initialization process time can be shortened.

Further, according to the second aspect of the invention, since the operation pulse number of the step motor is reset at the moment when the valve body starts to move from the valve opening limit to the valve closing side, all the variations for each product are absorbed. , The reference position can be actually determined, not estimated.

Further, according to the third aspect of the present invention, the control speed at the time of the normal idle air amount control is increased to improve the responsiveness, and the bounceback phenomenon occurs at the time of confirming the operation pulse number of the reference position and at the time of initialization. Therefore, the number of operation pulses of the step motor and the opening position of the idle control valve can be more correctly associated with each other.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an idle air amount control device.

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

FIG. 3 is a flowchart showing a procedure of determining the number of operation pulses of a reference position, which is executed when a battery is newly connected.

FIG. 4 is a diagram showing changes in the step motor drive signal and the number of operation pulses during the operation pulse number confirmation process.

FIG. 5 is a flowchart showing a control processing procedure of a step motor at the time of initialization.

FIG. 6 is a diagram showing changes in the step motor drive signal and the number of operation pulses at the time of initialization.

FIG. 7 is a graph showing a result of measuring occurrence of a bounceback phenomenon depending on a driving voltage and a driving frequency.

[Explanation of symbols]

4 ... passage 7 ... Valve 21 ... Switch B: Battery C: Control unit M: Step motor V: Idle control valve

Claims (3)

[Claims] 1. A passage (4) for guiding intake air when idling.
An idle control valve (V) for adjusting the opening of the idle control valve; a step motor (M) that exerts a driving force for opening and closing the idle control valve (V); and an opening position of the idle control valve (V) as a reference position thereof. From the reference position, the current position of the idle control valve (V) determined by the number of operation pulses of the step motor (M) from the reference position is set to the engine operating state. And a control unit (C) for controlling the operation of the step motor (M) by outputting a pulse signal of a pulse number corresponding to the difference between the target position and the current position so as to match the target position determined accordingly. The air amount control device includes a switch (21) for detecting that the opening position of the idle control valve (V) is at the valve opening limit, and the control unit (C) includes When the battery (B) is newly connected, the step motor (M) is operated at least until the opening limit is detected by the switch (21) after the opening position of the idle control valve (V) is once set as the closing limit. The number of pulses corresponding to the operation of the idle control valve (V) from the valve closing limit to the valve opening limit is determined and stored as the number of operating pulses corresponding to the reference position,
During the initialization process for making the opening position of the idle control valve (V) correspond to the operation pulse number of the step motor (M) from its reference position, the idle control valve (V)
The switch (2
The number of operating pulses of the step motor (M) when the step motor (M) is operated until it is detected in 1) is reset by the determined and stored number of pulses, and the idle control valve (V) is opened at the time of reset. An idle air amount control device characterized in that a degree position is set to the reference position. 2. The switch (21) is configured to conduct when the valve body (7) of the idle control valve (V) moves to its open limit, and the control unit (C) is configured to control the battery. During the new connection of (B) and the initialization process, the step motor (M) drives the valve body (7) to the valve opening side until the switch (21) becomes conductive.
The step motor (M) is operated in the reverse direction after the switch is activated, and the time when the switch (21) changes from the conductive state to the cutoff state is determined as the pulse number fixing timing and the reset timing. The idle air amount control device according to claim 1. 3. The control unit (C) sets the drive frequency of the step motor (M) when the idle control valve (V) is driven when the battery (B) is newly connected and during initialization processing. 2. The idle air amount control device according to claim 1, wherein the operation of the step motor (M) is controlled to be smaller than that during execution of idle air amount control by adjusting the opening degree of the idle control valve (V).