JPS61244852A - Idle revolution speed controller - Google Patents

Abstract

PURPOSE:To improve the operation performance in idling and improve fuel consumption by installing a revolution-range restricting means for restricting the revolution range of a step motor and a position adjusting means which outputs the number of steps increased or decreased by a prescribed number. CONSTITUTION:A step motor 62 which drives an intake flow-rate control means 63 for controlling the intake flow-rate on idling and a control circuit 61 for controlling the position of the step motor 62 are installed. A revolution-range restricting means 64 restricts the revolution range of the step motor 62. A position adjusting means 65 which outputs the number of steps increased or decreased by a prescribed number from the difference between the standard step corresponding to the restriction position and the memorized number of steps is installed. thus, the operation performance in idling can be improved, and fuel consumption can be improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an idle speed control device.

(Prior art) When idling, the amount of air-fuel mixture is low and the engine rotation is inherently unstable. Therefore, a flow control valve is provided in the bypass passage that bypasses the throttle valve, and the opening degree of this control valve is increased or decreased. There is an idle rotation speed control device that stabilizes engine rotation by maintaining the rotation speed at a predetermined value during idling by introducing auxiliary air.

Recently, idle rotation speed control has been incorporated into electronic control, and digital control using microcomputers is performed, but with the digitalization of this control technology, a digital actuator is being used to drive the flow rate control valve. A step motor is used.

A step motor generates rotational force by the electromagnetic force generated in the stator coil by passing a pulse current through the stator coil, and rotates the rotor in steps by a predetermined angle by sequentially switching the stator coils that apply the pulse current. It's something that will happen.

In this case, one switching is regarded as one step, and the period from fully open to fully open of the flow control valve is divided into a predetermined number of steps (for example, O corresponds to the fully closed position, 128 corresponds to the fully open position, etc.),
This number of steps corresponds to the position of the step motor.

In control using this step motor, the actual rotation speed is detected, and if this rotation speed is lower than the target idle rotation speed, the rotation speed is increased by increasing the number of steps and opening the control valve. If the rotation speed is higher than the target rotation speed, the number of steps is decreased and the control valve is closed, thereby lowering the rotation speed and performing feedback control of the actual rotation speed to the target rotation speed. (For example, see Japanese Unexamined Patent Publication No. 57-26238).

(Problem to be Solved by the Invention) By the way, in this case, since the step motor is simply driven to open and close the flow control valve according to the deviation from the target rotation speed, the step motor is not driven. The number of steps calculated or stored in a control circuit such as a microcomputer may decrease due to a drop in the voltage applied to the step motor, or a large torque may cause the step motor to temporarily stop moving even if a motor drive signal is output. and the actual motor position may not correspond and a deviation may occur.

The idle speed is selected to be the lowest speed at which engine speed does not become unstable and fuel consumption is reduced, but if the control valve opening decreases due to this discrepancy,
Engine rotation may become unstable, leading to unstable operation or, in extreme cases, engine stalling. Conversely, if the control valve opening increases, the engine speed will increase unnecessarily, resulting in engine braking becoming ineffective and fuel being wasted.

In addition, it may be possible to eliminate the deviation by detecting the actual opening of the flow control valve, but in order to constantly detect the opening of the flow control valve, it is necessary to install a potentiometer or to detect the opening of the flow control valve. Providing a position sensor such as a limit switch to detect a specific opening degree not only complicates the configuration and reduces reliability, but also poses problems with the accuracy of the position sensor and variations in installation position. come.

An object of the present invention is to provide a device that reliably holds a step motor at a reference position without providing a base position sensor or the like.

(Means for solving the problem α) FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. Reference numeral 63 denotes an intake flow rate control means for controlling the intake flow rate during idling, and includes, for example, a flow rate control valve interposed in a bypass passage that bypasses a throttle valve.

Reference numeral 62 denotes a step motor that drives the intake flow rate control means 62, and is driven by a motor drive signal from the control circuit 61.

The control circuit 61 determines the number of steps according to the engine operating state using liquid or table lookup, converts this number of steps into a motor drive signal, and outputs it to control the position of the step motor.This invention is comprised of the following two parts. The present invention is based on the premise that the idle speed control device is an idle rotation speed control device, and further includes a rotation range limiting means 64 and a position adjustment means 65.

That is, the rotation range limiting means 64 is the step motor 62.
Limit the rotation range of The position adjustment means 65 outputs the number of steps increased or decreased by a predetermined number based on the difference between the reference number of steps corresponding to this limit position and the number of steps stored at that time.

(Function) In a case where the flow rate control valve jumps due to an increase in the number of steps, if the fully open position of the flow rate control valve is set as the reference position of the step motor, the position adjusting means 65 is The number of steps obtained by adding a predetermined number of steps equal to the number of steps corresponding to the difference between the number of steps calculated in and the actual position of the step motor 62 is output as a motor drive signal.

The step motor 62 rotates according to the predetermined number of steps and reaches the fully open position, but the motor drive signal is still outputted to rotate the step motor 62. However, due to the rotation range limiting means 64, the step motor 62
Further rotation of the step motor 62 is prevented and the step motor 62 is held at the full 15H position.

Therefore, by holding the step motor 62 at the fully open position and then driving the step motor 62 using the fully open position as the reference position of the step motor 62, it becomes possible to drive the step motor 62 without any deviation at all times. By driving 62, the idle rotation speed can be precisely controlled to a predetermined target value.

As a result, it is possible to improve drivability by preventing jerky driving that occurs due to a decrease in the control valve opening, and it is also possible to improve fuel efficiency by suppressing unnecessary fuel consumption that occurs due to an increase in the control valve opening. can be achieved.

(Embodiment) FIG. 2 is an overall configuration diagram of an embodiment of the present invention. In the figure, 1 is an engine main body, 2 is an intake pipe, 3 is a throttle valve installed in the intake pipe 2, and 6 is a battery.

A flow rate control valve 8 is interposed in the bypass passage 4 that bypasses the throttle valve 3, and this flow rate control valve 8 drives a step motor 9 (controlled by a motor drive signal from a control unit 7 as a control circuit). It is driven by a 7-cut unit.

The control unit 7 is a central processing unit (CPU) 7
A. It is composed of a microcomputer consisting of a storage device (ROM 7B, RAM 7C), and an interface, and is configured to monitor engine speed, cooling water temperature, air conditioner operating status, output of the throttle switch that detects the fully open status of the throttle valve 3, battery voltage, etc. Step motor 9 depending on the operating condition
Denotal control.

FIG. 3 is a sectional view of a flow rate control valve 8 as an intake air amount control means and a step motor 9 that drives the flow rate control valve 8.

Flow control valve 8. The configuration of the step motor 9 is the same as that of the conventional example. As shown in the figure, a motor housing 10 holding a step motor 9 and valve housings 12 and 1 are secured to each other by bolts 13 via a motor housing end plate 11.

A seven flange 14 is integrally formed in the valve housing 12, and this seven flange 14 is fixed to the outer wall surface of the intake manifold and the lead gathering portion with bolts. A valve chamber 15 is formed within the valve housing 12, and this valve chamber 15 is connected to the valve housing 12.
The intake pipe 2 is connected to the intake pipe 2 upstream of the throttle valve 3 shown in FIG. 2 through a bypass pipe 16 fixed to the throttle valve 3 shown in FIG.

On the other hand, a cylindrical upper projection 17 is integrally formed at the tip of the seven flange 14, and a cylindrical air outflow hole 18 is formed within this projection 17. An annular groove 19a is provided at the inner end of the air outlet hole 18.
is formed, and a valve seat 19 is fitted into this annular groove 19a.

The step motor 9 includes a valve shaft 20, a rotor 21 disposed coaxially with the valve shaft 20, and a pair of stators 22 and 23 fixedly arranged with a slight gap from the cylindrical outer peripheral surface of the rotor 21. Equipped with.

The end of the valve shaft 20 is supported by a hollow cylindrical bearing 24 fixed to the motor housing 10.
The middle part of 0 is a bearing 2 fixed to the housing end plate 11.
Supported by 5.

An external thread 29 is threaded onto the outer circumferential surface of the valve shaft 20 located inside the motor housing 10, and this external thread 29 extends to the right of the valve shaft 20 to connect to a second stop pin 27, which will be described later.
It terminates at a position just beyond. In addition, the valve stem 20
A flat portion 30 is formed on the outer circumferential surface of the valve shaft 20 and extends to the right from the vicinity of the termination position of the external thread 29, while the support hole of the bearing 25 is formed on the outer circumferential surface of the valve shaft 20 as shown in Fig. Pt54. A cylindrical inner circumferential surface 31 and a flat inner circumferential surface 32 having complementary shapes.
has. Therefore, the valve shaft 20 is supported by the bearing 25 so as to be non-rotatable and slidable in the axial direction.

Further, as shown in FIG. 4, an outwardly projecting arm 33 is integrally formed on the outer circumferential surface of the bearing 25, while the housing end plate 11-I: has an arm 33 that matches the outer circumferential contour shape of the bearing 25. The contoured bearing has a fitting hole 34 shaped therein. Therefore, when the bearing 25 is fitted into the fitting hole 34 as shown in FIG. 3, the bearing 25 is supported non-rotatably on the housing end plate 11.

A valve body 36 having a substantially conical outer peripheral surface 35 is fixed to the tip of the valve shaft 20 with a nut 37, and an annular air flow passage 38 is formed between the outer peripheral surface 35 of the valve body 36 and the valve seat 19. Ru. Furthermore, a valve body 36 and a housing end plate 1 are disposed within the valve chamber 15.
A compression spring 39 is inserted between 1 and 1.

The rotor 21 has an inner cylinder 40 and an intermediate Ili? which is adhesively fixed on the outer peripheral surface of the inner cylinder 40. I41 and an outer @4 consisting of a permanent magnet adhesively fixed on the outer peripheral surface of the intermediate cylinder 41 with an adhesive.
2, and N poles and S poles are alternately formed in the circumferential direction on the outer peripheral surface of this permanent magnet outer cylinder 42, as will be described later. As can be seen from FIG. 3, one end of the intermediate fi 41 is supported by a ball bearing 43 supported by the motor housing 10.
is supported by an inner race 44, while an intermediate cylinder 41
The other end is supported by an inner race 46 of a ball bearing 45 supported by the housing end plate 11. Therefore, the rotor 21 is rotatably supported by these pair of ball bearings 43,45.

In addition, the outer thread 29 of the valve shaft 20 is located in the center hole of the inner cylinder 40.
An internal thread 47 is formed which meshes with the rotor 21 .
It can be seen that when the valve stem 20 rotates, the valve stem 20 is moved in the axial direction.

Next, the rotation range limiting means of the step motor, which is the essential part of the present invention, will be described as shown in FIG. 5(A).

FIG. 5(B) is an enlarged perspective view of section A in FIG. 3.

-0° which is an enlarged perspective view of part B. As shown in FIG. The first stop bin 26 and the inner cylinder 4 are press-fitted into the inner cylinder 4.
Rotation of the inner cylinder 40 is stopped by contact with the stopper 40A formed at 0.0.

On the other hand, as shown in FIG. 5(B), as the inner cylinder 40 rotates in the direction of arrow O, the valve shaft 20 slides to the left (valve opening direction), and the W42 press-fitted onto the valve shaft 20 moves. Stop pin 27
When the stopper 40B formed on the inner cylinder 40 comes into contact with the inner cylinder 40, the rotation of the upward inner cylinder 40 is stopped.

Therefore, the fully open position of the flow control valve 8 is set at the stop pin position shown in FIG. 5(A), and the fully closed position of the flow control valve 8 is set at the stop pin position shown in FIG. 5(B), and the step motor The rotation range of the rotor 21 is limited by these stop bins 26, 27 and stoppers 40A, 40B. Incidentally, a slit 28 is formed in the pongee receiver 24 through which the first stop bin 26 enters. Next, the pair of stators 22 and 23 fixedly arranged within the motor housing ring 10 will be described. The stators 22 and 23 have the same structure, and therefore
Only the VT structure of one stator 22 will be explained with reference to FIGS.

Referring to FIGS. 6 to 9, the stator 22 is comprised of a pair of stator core portions 51, 52 and a stator coil 53. As shown in FIGS. The stator core portion 51 has an annular side wall portion 54
, an outer cylinder part 55, and eight magnetic pole pieces 56 extending perpendicularly to the annular side wall part 54 from the inner peripheral edge of the annular side wall part 54, and these magnetic pole pieces 56 have a substantially triangular shape and are arranged at equal angles. They are arranged at intervals.

On the other hand, the stator core portion 52 is composed of an annular side wall portion 57 and eight magnetic pole pieces 58 extending perpendicularly from the inner peripheral edge of the annular side wall portion 57 to the annular side wall portion 57°. Similarly, they have a nearly triangular shape and are arranged at equal angular intervals. These stator core parts 51,52 are coupled to each other in such a way that their pole pieces 56 and 58 are equally spaced from each other, as shown in FIGS. 8 and 9. forms the stator core.

When a current is passed through the stator coil 53 in the direction shown by arrow A in FIG. 9, the stator coil 53
A magnetic field indicated by arrow B is generated around the magnetic field, and as a result, a south pole is generated in the magnetic pole piece 56 and a north pole is generated in the magnetic pole piece 58. Therefore, it can be seen that N poles and S poles are alternately formed on the inner peripheral surface of the stator 22. On the other hand, in the Pt59 diagram, if a current is applied to the stator coil 53 in the direction opposite to the arrow A, an N pole is generated in the magnetic pole piece 56 and an S pole is generated in the magnetic pole piece 58.

! The mlO diagram shows a stator 22 and a stator 23 arranged in tandem as shown in FIG. In addition,
In the Pt5lo diagram, components of the stator 23 that are similar to the StJ& elements of the stator 22 are designated by the same reference numerals. 1st
Adjacent pole pieces 5 of the stator 22 as shown in FIG.
6 and the magnetic pole piece 58 is 1, the magnetic pole piece 56 of the stator 23 is 1/2 that of the magnetic pole piece 56 of the stator 22.
It's off by just that. That is, assuming that the distance d between adjacent magnetic pole pieces 56 of the stator 22 is 1 pitch, the magnetic pole pieces 56 of the stator 23 are shifted by 1/4 with respect to the magnetic pole pieces 56 of the stator 22. On the other hand, as shown in FIG.
N poles and S poles are formed alternately in the circumferential direction on the outer circumferential surface of the permanent magnet outer cylinder 42, and the spacing between adjacent N and S poles is equal to the distance between adjacent magnetic pole pieces 56 and 58. Matches the interval.

Next, the operating principle of the step motor 8 will be explained.
FIG. 3 schematically shows the magnetic pole pieces 56, 58 of each stator 22, 23 and the outer peripheral surface of the outer cylinder 42 of the rotor 21 in a developed manner. FIG. 13(a) shows a case where only the one-phase excitation coil I is excited between times t1 and t2 in the t512 diagram, and at this time, the magnetic pole piece 56 of the stator 22 is the N pole, and the magnetic pole piece 58 is is the S pole. On the other hand, stator 23
The magnetic pole pieces 56 and 58 of the stator 22 and the S pole of the rotor outer cylinder 42 face each other, and the magnetic pole piece 58 of the stator 22 and the N pole of the rotor outer cylinder 42 face each other. are facing each other.

Next, when the two-phase excitation coil ■ is excited between times t2 and t3 in FIG. 12, the direction of the current in the two-phase excitation coil ■ and the direction of the current in the one-phase excitation coil I are the same. Therefore, as shown in FIG. 13(b), the stator 23
The magnetic pole piece 56 of the stator 23 becomes the north pole, and the magnetic pole piece 58 of the stator 23
becomes the south pole. Therefore, at this time, in the rotor outer cylinder 42, the S pole of the rotor outer f:l 142 is located between the magnetic pole piece 5G of the stator 22 and the magnetic pole piece 56 of the stator 23, while the N pole of the rotor outer cylinder 42 is the magnetic pole of the stator 22. It moves so that it is located between the piece 58 and the magnetic pole piece 58 of the stator 23.

As mentioned above, if the interval between adjacent magnetic pole pieces 56 of the stator 22 is one pitch, the rotor outer cylinder 42 shown in FIG. This means that it has been moved 1/8 pitch to the right in the figure.

Next, when the three-phase excitation coil ■ is excited between times L3 and t4 in Fig. 12, the direction of the current in the three-phase excitation coil ■ is opposite to the direction of the current in the one-phase excitation coil ■. As shown in FIG. 13(C), the stator 22
The magnetic pole piece 56 of the stator 22 becomes SF@, and the magnetic pole piece 56 of the stator 22
8 becomes the north pole. As a result, the rotor outer cylinder 42 shown in FIG. 13(e) is moved by 1/4 pitch to the right in FIG. 13 with respect to the rotor outer cylinder 42 shown in FIG. 13(b).

Thereafter, when the four-phase excitation coil ■ is similarly excited between times t4 and t5 in Fig. Move 1/4 pitch to the right with respect to the cylinder 42, then move 1/4 pitch to the right.
When the one-phase excitation coil I is excited again between times t5 and t6 in Fig. 512, the rotor outer cylinder 42 is moved relative to the rotor outer cylinder 42 in Fig. 13(d) as shown in Fig. 13(e). It will move 1/4 pitch to the right.

Therefore, when the 1-phase excitation coil I to the 4-phase excitation coil ■ are sequentially excited as shown in FIG. 13(b) to ttS13(e), the outside of the rotor @42 is 1
The rotor 21 rotates in one direction.

Next, the position adjustment means will be explained. W! to the reference position of this step motor 9! 4 is, in this example, CP
This is performed in U7A, and FIG. 14 is a flowchart explaining the control operation to the reference position. This operation is performed at predetermined time intervals, for example, as an interrupt routine.

The numbers in the figure indicate processing numbers.

Note that the movement of the rotor outer cylinder 42 by 1/4 pitch is defined as 1
The flow control valve 8 is divided into 128 steps from the fully closed position to the fully open position, and the number of steps is 0.
corresponds to the fully open position, and the number of steps 128 corresponds to the fully open position. In FIG. 13, there are four patterns (b) to (e) for moving one step, and the same pattern is repeated every four steps. In addition,(,
) are not included in the pattern.

In step 70, the number of steps S corresponding to the current step position stored in the non-volatile RAM 7C is read out, and in step 71, the reference step number 12 corresponding to the reference position of the step motor is read out.
The difference from 8 is calculated as 5l=128-8. Here, the reference position may be either a fully open position or a fully closed position where rotation of the rotor 21 is restricted, and in this example, the fully open position is selected, so the number of steps 128 corresponding to the fully open position is the reference step number. .

In 72, a predetermined number of steps ΔS is added to this 81 to obtain 5.
2=s, +ΔS is calculated. Here, .DELTA.S is a multiple of 4 (for example, 8) since the pattern for moving one step is 4. Note that when the fully closed position is selected as the reference position, ΔS is subtracted.

At step 73, a motor drive signal is outputted to drive the step motor 9 by the number of steps 82, for example when idle speed control is not being performed.

At step 74, the number of steps 128 corresponding to the reference position is stored in the nonvolatile RAM 7C.

The effect of the above configuration is explained using non-volatile RAM.
Note 1 in 7C! A case where the number of steps set and the actual position of the step motor deviate will be explained based on diagram f515. In other words, the number of stored steps is 1.
Assume that the number of steps corresponding to the actual motor position is 121, whereas the number of steps corresponding to the actual motor position is 25. In this example, the actual number of steps will be explained as 121, but the actual number of steps is usually unknown unless a sensor or the like is provided to detect the step position.

In this case, when the interrupt routine for adjusting the step motor 9 to the reference position is started, the CPU 7A reads the currently stored step number 125 and calculates the difference between the reference step number 128 and this step number 125. 51=3 is obtained, and a predetermined number of steps 8 is added to this 81 to obtain 52=11.

Based on this 82, the number of steps as a motor drive signal increases by 1 from 126 to 136 as shown by the broken line in FIG.

In accordance with this increase in the number of steps, the actual number of steps corresponding to the motor position increases as shown by the solid line in the figure, and the step motor 9 reaches 128, which corresponds to the fully open position, at the seventh step after being driven. In this position, #J4 inside the rotor
0 stopper 40B is the second stop bin 27 of the valve shaft 20.
comes into contact with. For this reason, even though the number of steps as a signal continues to increase, the rotor 21 cannot rotate any further, so it is held at the fully open position, which is the reference position, and the rotor 21 cannot be rotated. remaining 4
The step is simply a movement of the data pole.

Thereafter, 128 is stored in the RAM 7C, and in this state, the stored step number matches the motor position fFf at that time, and the adjustment of the step motor to the reference position is completed.

In other words, due to operational malfunctions such as a drop in the driving voltage of the step motor 9, a large torque acting on the step motor 9, and even if a motor drive signal is output, the step motor 9 does not move at times, and so on. There may be a discrepancy between the stored step number and the actual motor position, but the number of drive steps corresponding to this discrepancy is set in advance as the predetermined number of steps, and the The step motor is forcibly driven to the limit position by adding the predetermined number of steps, and the step motor 9 is driven using this limit position as a reference position.

Therefore, the motor position of the step motor 9 is adjusted to the reference position for each interrupt routine, and even if a deviation occurs, the deviation is absorbed by the adjustment to the reference position.
In the operating range where the idle rotation speed is controlled, the flow control valve 8 is driven by the step motor 9 with no deviation from the motor drive signal, and the idle rotation speed is controlled at a predetermined target. The value is precisely controlled.

In the conventional example, due to such deviation, for example, if the control valve opening decreases, the engine rotation becomes unstable and causes jerky operation, or in extreme cases, the engine stalls, and conversely, if the control valve opening increases, the engine malfunctions. As the engine speed increases, engine braking becomes ineffective and unnecessary fuel consumption occurs. On the other hand, this embodiment improves drivability by preventing drifting, etc. that occurs due to a decrease in the control valve opening, and also suppresses unnecessary fuel consumption that occurs due to an increase in the control valve opening. This results in improved fuel efficiency.

In addition, the step motor 9 can be used as a reference without providing a potentia meter to constantly detect the opening of the flow control valve, or without providing a position sensor such as a limit switch to detect a specific opening of the flow control valve. Since the position can be precisely adjusted, there is no need to take into consideration the accuracy of the position sensor and the variation in the installation position, which are necessary when installing these sensors, and the configuration is simplified and reliability is increased.

In addition, in this example, it was mentioned earlier that there are four patterns for step drive of the motor, but if you drive from any of these patterns by a multiple of 4, the step motor will always be in the same pattern position after driving. Because I'm coming to
Increased reliability in controlling motor position after driving.

(Effects of the Invention) The present invention includes an intake flow rate control means for controlling the intake flow rate during idling, a step motor for driving the intake flow rate control means, and a step motor that controls the position of the step motor by a number of steps depending on the engine operating state. A control circuit for controlling the number of idle times, a rotation range limiting means for limiting the rotation range of the step motor, the number of steps corresponding to this limit position, and the number of steps stored at that time. The step motor is adjusted to the reference position even if there is a discrepancy between the stored step number and the actual motor position. A certain limit! By forcibly driving the step motor up to 1, it is possible to eliminate deviations, and by adjusting the step motor to the reference position, it is possible to optimally control the idle rotation speed, which occurs due to a decrease in the control valve opening. It is possible to improve drivability during idling by preventing rough driving, and to improve fuel efficiency by suppressing unnecessary fuel consumption caused by increased control valve opening.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. tJS2 is an overall configuration diagram of an embodiment of the present invention, FIG. 3 is a sectional view of a flow control valve as an intake air amount control means and a step motor that drives this flow control valve, and FIG. [[Cross-sectional view taken along the -fir line, FIG. 5(A),
FIG. 5(B) is an enlarged perspective view of section A and an enlarged perspective view of section B of FIG. 3, respectively. Figure ttS6 and Figure 7 are perspective views of the stator core part, Figure 8.
The figure is a sectional view of the stator, FIG. 19 is a side sectional view taken along the line ■-■ in FIG. 8, FIG. 10 is a sectional plan view of the stator in FIG. FIG. 12 is a schematic side sectional view taken along line IX, FIG. 12 is a diagram showing motor drive pulses, and FIG. fjS13 is an explanatory diagram schematically showing the stator and rotor of the step motor. FIG. 14 is a flowchart explaining the operation performed by CPU 7A in FIG. 2, and FIG. f515 is a diagram explaining the operation of this embodiment. 2... Intake w, 3... Throttle valve, 4... Bypass i [[, 7... Control unit, ? A...
・CP II. 7C...RAM, 8...Flow rate control valve, 9...Step motor, 19...Valve seat, 20...Valve shaft, 21...
... Rotor, 22.23... Stator, 26... First stop pin, 27... Second stop pin, 36...
... Valve body, 40... ftff in rotor, 40A, 40
B... Stopper, 42... Rotor outside, 56.58
...Magnetic pole piece, 60...Operation state detection means, 61...
- Control circuit, 62... Step motor, 63... Intake flow rate control means, 64... Rotation range limiting means, 65.
...Position adjustment means. Patent applicant Nissan Motor Co., Ltd. Figure 3 Figure 4-'' ■ Figure 10 bd bd Figure 14

Claims (1)

[Claims] an intake flow rate control means for controlling the intake flow rate during idling; a step motor for driving the intake flow rate control means;
An idle rotation speed control device comprising a control circuit that controls the position of a step motor with a number of steps according to an engine operating state, comprising: a rotation range limiting means that limits the rotation range of the step motor; and a rotation range limiter that limits the rotation range of the step motor; An idle rotation speed control device comprising a position adjustment means for outputting a step number that is increased or decreased by a predetermined number from the difference between a reference step number and a stored step number at that time.