JPH11241667A - Engine intake air control system - Google Patents

Abstract

(57) [Problem] To integrate a step motor-driven idle control valve and an opening sensor for executing idle control into a passage forming body, and then reduce the horizontal and vertical widths of the throttle device as much as possible. The opening degree of the bypass passage, which is a reference for idle control, is appropriately associated with the control pulse of the step motor. An idle control valve is directly mounted on a passage forming member so as to open and close a valve member in a direction parallel to a plane passing through the center of an intake passage and an axis of a valve shaft. An opening sensor 24 for detecting the opening of the valve 18 is mounted on the passage forming body 15 alongside the idle control valve 45, and associates the opening of the bypass passage 38, which is a reference for idle control, with the control pulse of the step motor 48. In this case, the number of operation pulses of the step motor 48 is reset so that the position where the idle control valve 45 is driven to the valve opening side by a predetermined amount after the idle control valve 45 is once driven to the fully closed position is used as a control reference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air amount control apparatus for an engine, and more particularly, to a throttle valve and a throttle drum fixed to a valve shaft rotatably supported by a passage forming body across an intake passage, and idling. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake air amount control device for an engine in which intake air can be guided at any time, and an opening degree of a bypass passage connecting an upstream side and a downstream side of a throttle valve is adjusted by an idle control valve driven by a step motor.

[0002]

2. Description of the Related Art Conventionally, such an intake air amount control device for an engine is already known, for example, from Japanese Patent Application Laid-Open No. 4-318279 and Japanese Patent Publication No. 63-42106.

[0003]

Since the idle control valve only needs to be provided in a bypass passage bypassing the throttle valve, a bypass passage is formed by a pipe separate from the passage forming body, and is provided in the middle of the pipe. It is also possible to dispose an idle control valve in such a case, and this is also configured in Japanese Patent Publication No. 63-42106. However, a pipe line is required in addition to a passage forming body, and a valve seat is formed. Is also required. Then, in the above-mentioned Japanese Patent Application Laid-Open No. 4-318279,
By integrating and integrating the idle control valve with the passage forming body, the pipe and the valve seat component are not required.

On the other hand, in order to perform appropriate idle control, an opening sensor for detecting the opening of the throttle valve (opening from fully closed to fully open) or a fully closed position of the throttle valve in place of the opening sensor It is necessary to integrate and integrate such an opening sensor and an idle switch in the passage forming body as much as possible in order to simplify wiring.

[0005] Further, when a throttle device having a throttle valve, a throttle drum, a step motor drive type idle control valve, an opening sensor or an idle switch, etc. mounted on a passage forming body is mounted on an engine, it takes various space. The width of the throttle device along the axial direction of the valve shaft (hereinafter referred to as the width) or the width of the throttle device in the direction orthogonal to the axis of the valve shaft (hereinafter referred to as the vertical width). In some cases, it is required to reduce the size.
No. 79 discloses no such consideration, and both the horizontal width and the vertical width of the throttle device are relatively large. That is, since the opening sensor connected to the valve shaft on the side opposite to the throttle drum is attached to the passage forming body, the lateral width of the throttle device is relatively large. Also, the idle control valve is mounted on the passage forming body with the opening / closing operation direction being parallel to the center of the intake passage, but the passage forming body has a bolt insertion hole for attachment to the intake manifold and an icing prevention. There are restrictions on the arrangement for providing a hot water passage, a port for introducing fuel vapor from the canister, and a conduit for guiding the intake pressure to the intake pressure sensor, and a flange for mounting an idle control valve is also required. In a configuration in which the idle control valve is attached to the passage forming body in parallel with the intake passage, the vertical width of the throttle device is relatively large.

[0006] By the way, in the case of adjusting the amount of idle air using an idle control valve driven by a step motor,
Compared to the linear solenoid drive type, a sensor for detecting the opening of the idle control valve is not required and a simple and compact configuration is possible.However, the number of control pulses of the step motor and the opening of the idle control valve It is necessary to always maintain a constant and accurate correspondence with the degree position,
In addition, the problem of step-out always follows. That is, when the engine is cold started or when the voltage of the battery power source drops, the normal correspondence between the number of control pulses of the step motor and the opening position of the idle control valve cannot be maintained. Therefore, in order to maintain the correspondence between the number of control pulses of the step motor and the opening position of the idle control valve normally, the above-mentioned JP-B-63-421 was used.
In the device disclosed in Japanese Patent Application Laid-Open No. 06-2006, the idle control valve is driven to a fully closed or fully open 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 or fully open position is used as a reference position. I am trying to do it.

However, in the device disclosed in Japanese Patent Publication No. 63-42106, the idle control valve is not resiliently biased to the closing side, and the power transmission means provided between the idle control valve and the step motor is provided. Is composed of a rack and a pinion, and there is always a backlash between the rack and the pinion. Therefore, when the engine is idling with the restart of the engine, the operation of the step motor to the target position and the operation of the step motor A difference as shown in FIG. 11 occurs between the idle operation valve and the actual operating position.

That is, the operation amount of the stepping motor is ΔA ′ from the fully closed state of the idle control valve 45 ′ shown in FIG.
Until this operation, only the backlash between the rack 65 and the pinion 66 and the displacement of the excitation pattern in the step motor (a maximum of three steps in a general four-pole two-phase excitation step motor) result in FIG.
As shown in (b), the opening operation of the rack 65, that is, the idle control valve 45 'is not started, and the opening operation of the idle control valve 45' is delayed by a time ΔT. 1C until the step motor operates in the valve closing direction by the operation amount ΔA 'from the state of FIG.
As shown by 2 (d), the closing operation of the rack 65, that is, the idle control valve 45 'is not started, and the closing operation of the idle control valve 45' is delayed by a time ΔT.

Further, in a motor having a return spring for resiliently urging the idle control 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. 13 is generated between the actual operation position of the idle control valve. That is, from when the idle control valve is fully closed until the step motor operates by the operation amount ΔA ′, the opening operation of the idle control valve starts due to the backlash in the power transmission means and the deviation of the excitation pattern in the step motor. Is not performed, and the time for opening the idle control valve is Δ
After a delay of T has occurred and the idle control valve has been operated 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, 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 to set the fully closed position as the reference position. 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 opening operation of the idle control valve to the target opening degree is delayed. The opening of the valve becomes smaller than the target opening.

In the idle control, the idle control valve does not become fully closed, and fine adjustment is required near the fully closed state. However, as described above, the idle control valve is driven to open and close. If the actual operating position is different from the target position, accurate idle control is difficult. Further, in the case of the one having the return spring, since the target position is always greater than the actual operating position, the engine rotational speed becomes jerky, the idle rotational speed becomes unstable, and the engine may stall.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is intended to integrate a step motor driven idle control valve and an opening sensor for executing idle control into a passage forming body. Provided is an intake air amount control device for an engine, in which a width and a length of a throttle device can be set as small as possible and an opening degree of a bypass passage serving as a reference of idle control can be appropriately associated with a control pulse of a step motor. The purpose is to:

[0013]

In order to achieve the above object, the present invention provides a passage forming body having an intake passage, and a valve shaft rotatably supported by the passage forming body across the intake passage. A throttle valve fixed to the valve shaft so that the intake passage can be opened and closed, a throttle drum fixed to one end of the valve shaft outside the passage forming body, and a throttle valve capable of guiding intake air when idling A stepping motor driven type in which a valve body and a stepping motor whose operating directions are aligned to adjust the degree of opening of a bypass passage connecting the upstream side and the downstream side are connected via power transmission means having backlash. An intake air amount control device for an engine, comprising: a throttle device having an idle control valve; and a control unit controlling operation of the step motor. The idle control valve capable of seating the valve body on a valve seat formed in the passage forming body at an intermediate portion of the bypass passage provided in the adult body, has an interval from a plane passing through the center of the intake passage and the axis of the valve shaft. At the open position, the valve body is directly attached to the passage forming body so as to open and close the valve body in a direction parallel to the plane, and an opening sensor connected to the other end of the valve shaft is aligned with the idle control valve. The control unit is capable of controlling the operation of the step motor so as to execute idle control by adjusting the opening degree of the bypass passage after detecting the fully closed position of the throttle valve by the opening degree sensor. In associating the opening degree of the bypass passage as a reference for the idle control with the control pulse of the step motor, the idle control valve was once driven to the fully closed position. Characterized in that it is configured to reset the number of operating pulses of the step motor in order to a predetermined amount of control the position operated in the opening side criteria.

According to such a configuration, a step motor driven idle control valve which can seat the valve body on the valve seat formed in the passage forming body at an intermediate portion of the bypass passage provided in the passage forming body. Can be directly attached to the passage forming body with the direction parallel to the plane passing through the center of the intake passage and the axis of the valve shaft as the opening / closing operation direction. The vertical width of the throttle device can be reduced as compared with the one attached to the formation. Further, since the opening / closing operation direction of the idle control valve is set parallel to the plane at a position spaced from the plane, the lateral width of the throttle device is smaller than that in the case where the opening / closing operation direction is set on the plane. Become smaller. In addition, since the opening sensor and the idle control valve are attached to the passage forming body side by side, wiring to the opening sensor and the idle control valve can be integrated on the same side of the passage forming body. Further, in associating the opening degree of the bypass passage, which is a reference for the idle control, with the control pulse of the step motor, the position where the idle control valve is once driven to the fully closed position and then driven to the valve opening side by a predetermined amount is used as the control reference. After the reset, the actual operation position> the target position, and the idle control valve can be quickly driven to the target opening to obtain excellent startability. Becomes possible. In addition, the idle control valve can be quickly operated up to the required opening even during the steady idling operation, so that the engine rotation is smooth and engine stall does not occur. In addition, since the idle control valve has the same opening in either open or closed operating direction, accurate control is possible by eliminating the possibility of uneven rotation and engine stall when controlling the idle control valve at a low opening. It is possible to do.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

1 to 10 show an embodiment of the present invention. FIG. 1 is a front view of the throttle device as viewed from the upstream side, and FIG. 2 is a rear view of the throttle device as viewed from the downstream side. 3 is a sectional view taken along line 3-3 in FIG. 1, and FIG. 4 is a sectional view taken along line 4-4 in FIG.
FIG. 5 is a schematic sectional view of the throttle device taken along the line, and FIG.
FIG. 6 is a schematic sectional view of the throttle device taken along the line -5, and FIG.
7 is an enlarged vertical sectional view of the idle control valve, taken along line 6-6 of FIG. 6. FIG. 7 is a flowchart showing a control processing procedure of the step motor immediately after the ignition switch is cut off. FIG. FIG. 9 is a diagram showing a change in the operation position of the control valve, FIG. 9 is a diagram sequentially showing the operation state of the idle control valve and the power transmission means from the fully closed position, and FIG. 10 is a change in the actual position and the target position of the idle control valve after initialization. FIG.

Referring first to FIGS. 1 to 3, the throttle device 12 includes a metal passage forming body 15, and the passage forming body 15 includes an intake manifold 13 (see FIGS. 4 and 5) for a vehicle engine. An intake passage 16 extending substantially horizontally is formed in a state where the intake passage 16 is connected to the intake passage 16. A valve shaft 17 traversing the intake passage 16 is rotatably supported by the passage forming body 15, and opens and closes the intake passage 16. A possible butterfly type throttle valve 18 has a pair of screw members 1.
It is fixed to the valve shaft 17 by 9 and 19.

One end of the valve shaft 17 penetrates the passage forming body 15 with the bearing 27 interposed between the passage forming body 15 and the valve shaft 17. An annular step 17a to be brought into contact is provided. A nut 28 is coaxially screwed into one end of the valve shaft 17, and one end of the nut 28 abuts on the other end of the inner ring of the bearing 27 to coaxially surround the valve shaft 17. The throttle drum 30 is sandwiched and fixed between the other end of the cylindrical spacer 29. This throttle drum 30
A throttle wire (not shown) for transmitting a driving force corresponding to a throttle operation to the valve shaft 17 via the throttle drum 30 is wound around and connected to the throttle shaft.

The outer race of the bearing 27 is
And the passage forming body 15 coaxially surrounding the spacer 29.
The annular seal member 33 is fitted and held between the inner surface of the collar 32 and the outer surface of the spacer 29. A first return spring 34, which is a coiled torsion spring, is interposed between the throttle drum 30 and the collar 32.

On the other hand, the other end of the valve shaft 17 is
The bush 2 is attached to a cylindrical support portion 20 provided integrally with the bush 5.
1, and a lever 22 is fixed to the other end of the valve shaft 17 protruding from the support portion 20. In addition, the passage forming body 15 surrounds the support
A mounting cylinder portion 23 that protrudes outward more is provided integrally, and the lever 2 is provided at an outer end opening of the mounting cylinder portion 23.
The flange portion 25 of the opening sensor 24 connected to the opening 2 is fastened by a plurality of screw members 26.

A second return spring 35, which is a coil-shaped torsion spring, is provided between the lever 22 and the passage forming body 15 at the other end of the valve shaft 17.
Cooperates with the first return spring 34 to exert a spring force for urging the valve shaft 17 in the valve closing direction of the throttle valve 18.

4 and 5, a bypass passage 38 connecting the upstream side and the downstream side of the throttle valve 18 to guide the intake air at the time of idling bypasses the throttle valve 18 in the passage forming body 15. The bypass passage 38 is composed of an upstream passage 39 and a downstream passage 40. Thus, one end of the upstream passage 38 is opened on the inner surface of the intake passage 16 upstream of the throttle valve 18, and the other end of the upstream passage 38 is
Joint surface 15 of passage forming body 15 with intake manifold 13
a. That is, the other end of the upstream passage 39 is closed by the intake manifold 13 when the intake manifold 13 is joined to the passage forming body 15. The downstream passage 40 is provided in the passage forming body 15 at a position adjacent to the upstream passage 39 along the circumferential direction of the intake passage 16, and one end of the downstream passage 40 is connected to the upstream passage 3.
9 is disposed at a position corresponding to the intermediate portion of the downstream passage 40.
The other end is opened at the joint surface 15 a of the passage forming body 15 and communicates with the downstream end of the intake passage 16. Therefore, when the intake manifold 13 is joined to the passage forming body 15, the other end of the downstream passage 40 communicates with the downstream end of the intake passage 16.

Referring also to FIG. 6, the opening of the bypass passage 38 is adjusted by a step motor driven idle control valve 45 which is directly mounted on the passage forming body 15 along with the opening sensor 24. The idle control valve 45 has a valve body 46 that can be seated on a valve seat 41 formed in the passage forming body 15 at an intermediate portion of the bypass passage 38.
Are connected to a step motor 48 via a power transmission means 47 having a backlash.

The valve seat 41 is formed with a valve hole 42 communicating with an intermediate portion of the upstream passage 39 in the bypass passage 48 and facing one end of the downstream passage 40.
5, and the valve hole 42 has an axis parallel to the plane 43 at a position perpendicular to the valve shaft 17 and spaced outwardly from a plane 43 passing through the axis of the intake passage 16. The passage forming body 15. The passage forming body 15 has a mounting hole 44 coaxial with the valve hole 42.
Are provided so as to open the inner end to the downstream side passage 40 and open the outer end to the outer side surface of the passage forming body 15.

Although the structure of the stepping motor 48 is well known in the art, the structure thereof will not be described in detail, but a slight gap is provided between the rotor 50 having the permanent magnet 49 on the outer peripheral surface and the outer peripheral surface of the rotor 50. And a pair of stators 51 and 52 that are fixedly arranged with a space therebetween and are adjacent in the axial direction. The stators 51 and 52 are provided in common in a cylindrical mold part 53 made of synthetic resin,
Numeral 0 is rotatably supported by the mold portion 53 via a ball bearing 54 so as to prevent movement in the axial direction.

The housing 55 of the step motor 48
Is connected to the outer surface of the passage forming body 15 by a plurality of bolts 57 so that a part of the step motor 48 projects into the mounting hole 44. .

The power transmission means 47 is formed by screwing a driven shaft 58 having one end coaxially and integrally connected to the valve body 7 and a rotor 50 of a step motor 48. That is, the male screw 59 provided on the driven shaft 58 is
And a guide groove 61 formed in the outer surface of the driven shaft 58 along the axial direction thereof, and a protrusion 6 provided in the mold portion 53.
By the fitting of 2, the rotation of the driven shaft 58 around the axis is prevented. Therefore, the driven shaft 58 operates in the axial direction according to the rotation of the step motor 48,
This causes the idle control valve 45 to open and close. In addition, a coil-shaped return spring 63 is provided between the valve body 46 and the mold portion 53. The spring force of the return spring 63 causes the idle control valve 45 to move in the valve closing direction, that is, the valve body 46. Is urged in the direction of seating the valve seat 41 on the valve seat 41.

The opening / closing operation direction of the valve body 46 is coaxial with the axis of the valve hole 42. The valve hole 42 extends outward from a plane 43 passing through the center of the intake passage 16 and the axis of the valve shaft 17. The step motor-driven idle control valve 45 is parallel to the plane 43 at a position spaced from the plane 43 because the idle control valve 45 has an axis parallel to the plane 43 at a position spaced away from the plane 43. The valve body 46 is mounted directly on the passage forming body 15 at a position where the valve body 46 is opened and closed in the direction, that is, at a position spaced apart from the plane 43 by an axis d parallel to the plane 43.

An intake pressure sensor 64 for detecting the intake pressure of the intake passage 16 is also attached to the passage forming body 15, and the intake pressure sensor 64 is arranged so as not to interfere with the idle control valve 45. It is attached to the outer surface of the passage forming body 15 in a direction orthogonal to 43.

The operation of the step motor 48 is controlled by a control unit C (see FIGS. 4 and 5). The control unit C receives a signal from an opening sensor 24 for detecting the opening of the throttle valve 18. Is input.

The control unit C controls the operation of the step motor 48 so as to execute idle control by adjusting the opening of the bypass passage 38 after the opening sensor 24 detects the fully closed position of the throttle valve 18. The operation of the step motor 48 is controlled by open loop control until the engine complete explosion, and after the engine complete explosion, the operation of the step motor 48 is controlled by feedback control so as to reach a target engine speed corresponding to the engine coolant temperature. Thus, in the open loop control up to the complete explosion of the engine, the control unit C previously associates the opening position of the idle control valve 45 with the number of operating pulses of the step motor 48 from the reference position, and sets the position from the reference position. The target position is set so that the current position of the idle control valve 45 determined by the number of operation pulses of the step motor 48 matches a target position predetermined as an opening required for starting according to the engine operating state (specifically, engine coolant temperature). Then, the operation of the step motor 48 is controlled by outputting a pulse signal having the number of pulses corresponding to the difference between the current positions.

The timing of associating the opening of the bypass passage 38, which is the reference for the idle control, with the control pulse of the step motor 48 is, for example, immediately after the ignition switch is turned off.
Controls the operation of the step motor 48 in accordance with the procedure shown in FIG. 7, and in step S1, the number of repetitions N
Is set to “0”, and in step S2, the number of repetitions N
Check whether or not has become equal to or greater than the set number of times “N0”.
If <N0, "1" is added to the number of repetitions N in step S3, and the number of operating pulses MP of the step motor 48 is subtracted by "1" in step S4, and the process returns to step S2.

The set number of times "N0" is set to a value equal to or greater than the number of operating pulses of the step motor 48 for operating the idle control valve 45 from the fully open position to the fully closed position. Step S4
By the above processing, the idle control valve 45 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 control valve 45 is at the fully closed position, the number of operation pulses MP of the step motor 48 is added by "1" in step S5, and in step S6, the number of operation pulses MP is equal to the predetermined number of pulses MP0. 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 48 so that the rotor 50 of the power transmission means 47 operates more than the backlash of the power transmission means 47. S
By the processes in S5 and S6, the idle control valve 45 is driven in the valve opening direction from the fully closed position to the set position.

In step S7 after the idle control valve 45 is opened to the set position in this way, the number MP of operating pulses of the step motor 48 is reset to set the set position as a reference position for idle control. Initialize.

In the next step S8, the number of operating pulses MP of the step motor 48 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. If it is MP1, the process returns to step S8.

Therefore, after the reset of the number of operation pulses of the step motor 48 is completed, the step motor 48 is operated by the predetermined number of pulses MP1, and the idle control valve 45
Is driven in the valve opening direction from the reference position. Thereafter, the power is turned off in step S10, and the operation of the step motor 48 is stopped.

The operation of the step motor 48 and the idle control valve 45 immediately after the ignition switch is cut off is shown in FIG.
It is as shown in, set in the closing direction the number from time t ₁ the engine is stopped the ignition switch is turned OFF "N0"
By driving signal to the stepping motor 48 the number of pulses only is given, idle regulating valve 45 is surely becomes a fully closed state be in any position when the ignition switch blocked at time t _2, the then the predetermined number of pulses The step motor 48 is operated in the valve opening direction by MP0. The predetermined number of pulses MP0 is set so as to be at a position near the fully closed position where the idle control valve 45 is slightly opened, and is, for example, 10 pulses. By Thus a predetermined pulse number MP0 to step motor 48 is actuated in the opening direction, when the idle regulating valve 45 is driven in the opening direction to a set position from the fully closed position at time t _3, the The number MP of operation pulses of the step motor 48 is reset so as to determine the position as a reference position for idle control. From further time t _3, the step motor 48 by a predetermined number of pulses MP1 is actuated in the opening direction. , Idle regulating valve 45 at time t ₄ is when further activated in the opening direction from the reference position, so that the operation of the step motor 48 is stopped.

Here, the operation of the idle control valve 45 from the fully closed position and the operation state of the power transmission means 47 at that time are as shown in FIG. 9, and the idle control shown in FIG. When the valve 45 is fully closed, the power transmission means 4
7 and the displacement of the excitation pattern in the step motor 48
9B, the idle control valve 45 is in the fully closed state as shown in FIG. 9B, and then the step motor 48 is further operated to open the idle control valve 45 to a certain opening. At this time, the number of operation pulses of the step motor 48 is reset as the reference position of the idle control valve 45.

Next, the operation of this embodiment will be described. In the middle of the bypass passage 38 provided in the passage forming body 15 of the throttle device 12, a valve seat 41 is provided in the passage forming body 15.
A step motor-driven idle control valve 45 that allows the valve body 46 to be seated on the valve seat 41 is parallel to a plane 43 passing through the center of the intake passage 16 and the axis of the valve shaft 17. The opening and closing operation direction is directly attached to the passage forming body 15, so that the opening / closing operation direction is a direction orthogonal to the axis of the intake passage 15.
The vertical width of the throttle device 12 can be made smaller than that of the throttle device 12 attached to the passage forming body 15. Further, since the opening / closing operation direction of the idle control valve 45 is set parallel to the plane 43 at a position spaced from the plane 43 by a distance d, compared to the case where the opening / closing operation direction is set on the plane 43, The width of the throttle device 12 is also reduced.

Further, since the opening sensor 24 and the idle control valve 45 are attached to the passage forming body 15 side by side, the opening sensor 24 and the idle control valve 4
It is possible to concentrate the wiring to 5 on the same side of the passage formation.

Further, in associating the opening degree of the bypass passage 38, which is a reference for idle control, with the control pulse of the step motor 48, the idle control valve 45 is fully operated by the operation of the step motor 48, for example, immediately after the ignition switch is shut off. The idle control valve 45 is driven from the fully closed position to the set position by operating the rotor 50 beyond the backlash in the power transmission means 47, and the set position is used as a reference for idle control. The number of operation pulses of the step motor 48 is reset to determine the position, and the step motor 48 is further operated in the valve opening direction by a predetermined number of steps so that the idle control valve 45 is further opened from the reference position in the valve opening direction. ing.

After the initialization by resetting the number of operation pulses of the step motor 48 by such control processing, the operation of the step motor 48 to the target position and the idle control valve 45 accompanying the operation of the step motor 48 are performed.
The actual operating position changes as shown in FIG.

That is, after the initialization, the actual operation position of the idle control valve 45 is larger than the target position by the operation amount Δ
A (the amount obtained by subtracting the backlash δ of the power transmission means 47 and the deviation of the excitation pattern in the step motor 48 from the total operation amount of the step motor 48 at the time of initialization), and the step motor 4 reaches the target position.
8, the idle control valve 45 is opened and closed without delay. Therefore, when the engine is restarted,
The responsiveness can be improved by promptly operating the idle control valve 45 to the target opening. In addition, even when performing fine adjustment near the fully closed position, the idle control valve 45
Since the actual operating position does not differ between the valve opening drive and the valve closing drive, accurate idle speed control is possible,
In addition, since the actual operating position is greater than the target position, it is possible to prevent the engine speed from becoming jerky, to enable stable idle control, and to minimize the possibility of engine stall.

Further, since the idle control valve 45 is in the position slightly opened from the fully closed position in the ignition switch cutoff state, there is no risk of icing, and the idle control valve 45 is further opened and held after initialization. Thus, the idle control valve 45 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 rotation speed is performed so that the target engine rotation speed corresponds to the engine cooling water temperature. Since the actual operating position is corrected to the position, no problem occurs.

In associating the opening of the bypass passage 38, which is a reference for the idle control, with the control pulse of the step motor 48, the idle control valve 45 is driven to the fully closed position by the operation of the step motor 48.
The actual operating position can be made larger than the target position by resetting the number of operation pulses of the step motor 48 by offsetting the step motor 48 to the minus side by, for example, 10 pulses. Then, the control by the control unit C becomes complicated. That is, the idle control valve 45 is not completely closed at the time of idle control by adjusting the opening degree of the bypass passage 38, and precise opening / closing control of the idle control valve 45 near the slightly opened fully closed position is executed. Therefore, according to the present invention,
In associating the opening of the bypass passage 38 as a reference for the idle control with the control pulse of the step motor 48, the step motor 48 is operated so as to be slightly driven from the fully closed position of the idle control valve 45 in the valve opening direction. , The valve body 46 of the idle control valve 45 is
Therefore, there is no indication of the pulse number on the minus side due to the control of the step motor 48. For this reason, there is no need to give a negative offset instruction at the time of the reset, and there is no need to give a negative instruction and storage, so that control by the control unit C is simplified.

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, power transmission means 47 may be constituted by a rack and a pinion. The timing for associating the opening degree of the bypass passage 38 as a reference for the idle control with the control pulse of the step motor 48 is as follows.
In addition to the above-described immediately after the ignition switch is cut off, the timing may be before the starter operation is started immediately after the ignition switch is turned on or after the engine is started.

[0051]

As described above, according to the present invention, the vertical width of the throttle device can be reduced as compared with the case where the idle control valve is attached to the passage forming body, with the direction orthogonal to the valve shaft being the opening / closing operation direction. The width of the throttle device can be reduced, and the width and length of the throttle device can be reduced as compared with the case where the opening / closing operation direction of the idle control valve is set on a plane passing through the center of the intake passage and the axis of the valve shaft. Can be reduced to make the throttle device more compact. Further, by arranging the idle control valve and the opening degree sensor, it is possible to concentrate wiring to the opening degree sensor and the idle control valve on the same side of the passage forming body. Further, in associating the opening degree of the bypass passage, which is a reference of the idle control, with the control pulse of the step motor, the position where the idle control valve is driven to the valve opening side by a predetermined amount after the idle control valve is once driven to the fully closed position is used as the control reference. By resetting the number of operation pulses of the step motor, the actual operation position> the target position after the reset, and the idle control valve can be quickly driven to the target opening to obtain excellent startability. It is possible to quickly operate the idle control valve up to the required opening even during steady idle operation,
The engine runs smoothly and there is no risk of engine stall. In addition, since the idle control valve has the same opening in either open or closed operating direction, accurate control is possible by eliminating the possibility of uneven rotation and engine stall when controlling the idle control valve at a low opening. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a front view seen from an upstream side of a throttle device.

FIG. 2 is a rear view as viewed from a downstream side of the throttle device.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a schematic sectional view of the throttle device taken along line 4-4 in FIG. 1;

FIG. 5 is a schematic sectional view of the throttle device taken along line 5-5 in FIG. 2;

FIG. 6 is an enlarged vertical sectional view of the idle control valve shown in FIG. 1 along line 6-6.

FIG. 7 is a flowchart showing a control processing procedure of the step motor immediately after the ignition switch is cut off.

FIG. 8 is a diagram showing changes in a step motor drive signal and an idle control valve operating position immediately after the ignition switch is shut off.

FIG. 9 is a view sequentially showing the operation states of the idle control valve and the power transmission means from the fully closed position.

FIG. 10 is a diagram showing changes in the actual position and the target position of the idle control valve after initialization.

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 no return spring.

FIG. 12 is a view sequentially showing the operation state of the idle control valve and the power transmission means from the fully closed position in a conventional example having no return spring.

FIG. 13 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 12 ... Throttle device 15 ... Passage forming body 16 ... Intake passage 17 ... Valve shaft 18 ... Throttle valve 24 ... Opening sensor 30 ... Throttle drum 38 ... Bypass passage 41: Valve seat 43: Flat surface 45: Idle control valve 46: Valve element 47: Power transmission means 48: Step motor C: Control unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 33/00 318Z

Claims (1)

[Claims] 1. A passage formation (15) having an intake passage (16), a valve shaft (17) rotatably supported by the passage formation (15) across the intake passage (16), A throttle valve (18) fixed to the valve shaft (17) so as to open and close the intake passage (16), and a passage forming body (15)
A throttle drum (30) fixed to one end of the valve shaft (17) on the outer side of the throttle valve, and a bypass passage () connecting an upstream side and a downstream side of the throttle valve (18) so as to guide intake air at the time of idling. 38) A step motor-driven type in which the valve body (46) and the step motor (48) whose operating directions are aligned to adjust the opening degree is connected via a power transmission means (47) having a backlash. An intake air amount control device for an engine, comprising: a throttle device (12) having an idle control valve (45); and a control unit (C) for controlling the operation of the step motor (48). ), A passage forming body (15) at an intermediate portion of the bypass passage (38).
The idle control valve (45) capable of seating the valve element (46) on a valve seat (41) formed in the center of the intake passage (16) and an axis of the valve shaft (17). The valve body (46) is directly attached to the passage forming body (15) so as to open and close the valve body (46) in a direction parallel to the plane (43) at a position spaced from the valve shaft (17). An opening sensor (24) connected to the other end of the valve is mounted on the passage forming body (15) along with the idle control valve (45), and the control unit (C) is controlled by the opening sensor (24). After the fully closed position of the throttle valve (18) is detected, the operation of the step motor (48) can be controlled so as to execute idle control by adjusting the opening degree of the bypass passage (38), and a bypass passage serving as a reference for the idle control. (38) In associating the degree with the control pulse of the step motor (48), the position of the idle control valve (45) once driven to the fully closed position and then driven toward the valve opening side by a predetermined amount is used as a reference for control. 48) An intake air amount control device for an engine, wherein the number of operation pulses is reset.