JPH0316511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electromagnetically driven idle control valve installed in an intake passage of an internal combustion engine, and particularly to one with improved fail-safe function.

<Prior Art> In internal combustion engines such as gasoline engines, the engine rotational speed during idling is generally controlled by controlling the intake flow rate through a bypass passage that communicates between the upstream and downstream of an intake throttle valve in the engine intake passage. It's in control.

A conventional example of an idle speed control valve that performs this type of intake flow rate control is shown in FIG. 2, for example.

That is, a part of the cylindrical surface is attached to a sealing surface 3a on a housing 2 in which an intake passage 1 connected to a passage bypassing an intake throttle valve of an internal combustion engine (not shown) is formed.
A valve seat 3 is provided, and a valve body 4 having a sealing surface 4a formed of a part of a cylindrical surface corresponding to the valve seat 3 is provided. The valve body 4 is fixed to a freely rotatable support shaft (not shown), and by rotating together with this support shaft, the opening area of the intake passage 1 formed in the valve seat 3 is changed to change the intake flow rate. control.

This rotational drive of the valve body 4 is caused by a magnetic field generated by two coils of an armature (not shown) fixed to the spindle and a magnetic field of a permanent magnet (not shown) disposed near the outer periphery of the armature. done by force. Here, the torque generated by the magnetic field of one coil provides torque in the valve opening direction, and the torque generated by the magnetic field of the other coil provides torque in the valve closing direction.

Therefore, by alternately inputting pulse signals to the coils that generate torque in the valve opening and closing directions, and changing the energization time ratio to each coil, that is, the duty ratio, the valve opening or closing direction that occurs can be changed. The torque value will change depending on the duty ratio.

On the other hand, a stopper 5 provided on a continuous portion of the valve body 4 is brought into contact with a stopper 6 provided on the housing 2 by a helical return spring, and the returning torque in the valve closing direction by this return spring is constantly applied integrally with the armature. It is attached to rotating parts.

As a result of the above, the armature is held at a rotational position where the torque in the valve opening direction generated by energizing the coil and the return torque in the valve closing direction by the return spring are balanced. That is, by changing the duty ratio, the rotational position of the armature and the valve body 4 that rotates integrally with the armature is stabilized, the valve opening is adjusted, and the intake flow rate is controlled.

Note that the valve-closing coil is omitted, and by controlling the duty ratio of the energizing pulse to the valve-opening coil, the torque in the valve-opening direction generated in the valve-opening coil and the torque in the valve-closing direction caused by the return spring can be adjusted. Some devices control the valve opening in balance.

<Problems to be Solved by the Invention> Incidentally, in these idle speed control valves, due to an abnormality in the armature coil or the control circuit, the valve opening coil may remain energized (duty ratio 100%) or may become energized. In order to prevent the engine rotational speed from increasing abnormally when the situation approaches , there is a system that performs a fail-safe as shown in the flowchart of FIG.

In other words, the engine rotational speed N is an abnormally high upper limit value N _NG
is exceeded and the energization pulse duty ratio is maintained at the minimum state for a predetermined period of time, the energization to the control valve is kept OFF and the return spring is set to the fail-safe position. (Even if the power supply is cut off due to a failure in the control equipment, etc., the return spring will set it to the fail-safe position).

However, in such conventional fail-safe control, in order to avoid fail-safe operation in the event of a transient abnormality, fail-safe is performed with a predetermined grace period. There was a problem in that the speed increased abnormally regardless of the driver's will.

The present invention has been made in view of these conventional problems, and is an internal combustion engine idle system that reliably prevents an abnormal increase in idle rotation speed from the beginning of a failure by changing the valve opening area characteristics. The purpose of this invention is to provide a speed control valve.

<Means for Solving the Problems> For this reason, the present invention has the shape of the valve opening formed between the valve body and the valve seat such that the duty ratio of the energizing pulse to the valve opening coil is a predetermined value. At the valve body rotation position when the valve body is rotated above the valve body, the opening area is configured to be narrowed to obtain a predetermined fail-safe intake air flow rate.

<Function> In this way, in the event of an abnormality in which the valve opening coil is energized and then de-energized, the engine rotational speed increases because the valve opening area is automatically narrowed down depending on the valve rotation position at that time. is immediately suppressed.

<Example> Hereinafter, an example of the present invention will be described based on FIG. 1.

In the figure, a cylindrical member 13 is press-fitted into a cylindrical portion 12a of a housing 12 having an intake passage 11. The cylindrical member 13 has openings 13a and 13b formed in a portion thereof facing the intake passage 11,
It also functions as a valve seat with the inner cylindrical surface serving as a sealing surface 13c. A valve body 14 having a sealing surface 14a and an opening 14b formed of a part of a cylindrical surface corresponding to the valve seat is mounted around a fixed shaft 15 in bearing parts 16 and 1.
It is fixed to a hollow support shaft 18 which is supported by a shaft 7.

The housing 12 as a fixed body is provided with a stopper 19, and the continuous portion of the valve body 14 is provided with a corresponding stopper 20. Further, a helical return spring 21 is interposed between the valve body 14 and the housing 12, and the valve body 14 is urged to rotate in the direction of the stopper 20. here,
The positions of the stoppers 19 and 20 provided on the housing 12 and the valve body 14 are
The position of the valve body 14 when the valve body 20 comes into contact with the valve element 20 is set to be the valve closed position.

The armature 2 has two coils that generate magnetic fields in opposite directions on the hollow support shaft 18.
2 is fixed, and permanent magnets 24 and 25 are fixed to the cover 23 near the outer periphery of the armature 22. 2
6 is a commutator for guiding energizing pulses to each of the two coils of the armature 22.

Next, the shape of the valve opening according to the present invention formed between the slit-shaped opening 13a on the valve seat side and the opening 14b on the valve body 14 side will be explained with reference to FIG. 1C.

In the figure, the solid line shows the expanded opening 14b on the valve body 14 side, and the dotted line shows the opening 13a on the valve seat side. Under normal conditions, the duty ratio of the energizing pulse to the valve opening coil of the armature 22 (hereinafter simply referred to as duty ratio) is set so that the valve opening area ranges from a minimum to a maximum within a range of approximately 0 to 80%.

That is, the relative position of the opening 13a on the valve seat side with respect to the opening 14b of the valve body 14 moves within the range indicated by A in the figure.

In addition, in the event of an abnormality where the duty ratio exceeds 85%, the relative position of the opening 13a on the valve seat side is changed to B as shown in the figure.
The shape of the opening 14b is formed such that it is set within the section and the valve opening area is narrowed.

With such a configuration, the valve opening area can be adjusted by controlling the duty ratio of the energizing pulses to the valve opening coil and the valve closing coil during normal times, and the intake flow rate can be controlled in the same way as in the conventional case. Controlled by idle rotation speed.

Also, if the power to the two coils is cut off due to a failure in the control equipment, etc., return spring 2
1, the stoppers 19 and 20 are set at a position where they come into contact with each other (duty ratio 0% position), a fail-safe intake flow rate is obtained, and a predetermined rotational speed is maintained.

In the present invention, when the duty ratio becomes abnormally high, such as exceeding 85%, the valve opening area is narrowed, so that the same fail-safe intake flow rate as above can be obtained, and the predetermined rotational speed can be quickly reached. can be calmed down.

In this embodiment, a valve having a valve-opening coil and a valve-closing coil was used, but a valve having only a valve-opening coil and using a return spring to balance the torque in the valve-opening direction was used. Of course, it can also be applied to

<Effects of the Invention> As explained above, according to the present invention, when a failure occurs in which the valve opening coil is energized and then de-energized, the valve opening area is narrowed down. It is possible to reliably prevent the temperature from rising even temporarily, improving safety.

[Brief explanation of drawings]

1A and 1B show the configuration of an embodiment of the present invention, A is a cross-sectional view of the main part, B is a longitudinal sectional view, and FIG. 1C is a diagram showing the characteristics of the valve opening area in the above embodiment,
FIG. 2 is a cross-sectional view showing a conventional example of an idle speed control valve, and FIG. 3 is a flowchart of fail-safe control of the idle rotation speed of the conventional example. 11...Intake passage, 13a...Opening, 13c
... Seal surface, 14a ... Seal surface, 14b ...
Opening, 22...Amayu Chua.

Claims (1)

[Claims] 1. An intake passageway opening into a valve seat having a part of the rotational surface as a sealing surface, a valve body having a sealing surface of a part of the rotational surface corresponding to the rotational surface, and a valve opening coil. By controlling the duty ratio of the energization pulse that drives the valve coil in the valve opening direction, the opening area of the intake passage that opens to the valve seat is changed as the valve body rotates, thereby controlling the intake flow rate. In an idle speed control valve of an internal combustion engine to be controlled, the valve opening shape formed between the valve body and the valve seat rotates when the duty ratio of the energizing pulse to the valve opening coil exceeds a predetermined value. An idle speed control valve for an internal combustion engine, characterized in that the opening area is narrowed at the position to obtain a predetermined fail-safe intake flow rate.