JPH0680357B2 - Idle rotation control device for automobiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an idle speed control for automatically controlling an idle speed of a vehicle to a set speed according to an operating state of an engine (for example, water temperature or outside air temperature). The present invention relates to a device, and more particularly to an idle rotation control device for an automobile, which is suitable for electronic control.

[Conventional technology]

As described in Japanese Patent Laid-Open Publication No. 56-116966, a conventional idle rotation control device is configured to generate two forces in opposite directions so as to eliminate the influence of negative pressure acting on the metering valve. A metering valve was provided.

[Problems to be Solved by the Invention]

The above-mentioned prior art has a problem that the force applied to the valve becomes unbalanced due to the increase or decrease in the flow rate of the air due to the shape of the air passage, the shape of the valve, etc., and it is difficult to obtain the valve displacement proportional to the applied current. It was

An object of the present invention is to provide an idle rotation control device for a vehicle, which can obtain a valve displacement proportional to a current.

[Means for Solving the Problems]

The above-mentioned object is a cylindrical solenoid coil that converts an input electric quantity into a position output, a core at the center of the solenoid coil and a plunger that is inserted into the core and has a valve element at one end, and an air bypassing an intake pipe. Which forms an air passage through which a valve flows, a valve which controls the flow rate of the air flowing through the air passage in proportion to an electric signal input to the solenoid coil, and an upstream side and a downstream side of a valve seat facing the valve. In an idle rotation control device for an automobile, which comprises a diaphragm that is displaced according to a pressure difference and a diaphragm chamber for pressure correction formed by the diaphragm, the air passage on the upstream side of the seat communicates with the diaphragm chamber. A variable valve whose opening area continuously changes depending on the position of the valve at the end of the passage that is close to the diaphragm chamber. It is achieved by providing the office.

[Action]

Since the opening area of the variable orifice continuously changes according to the position of the valve that controls the air flow rate and the pressure inside the diaphragm chamber is adjusted, the correction force of the diaphragm can be changed according to the input to the solenoid coil, Stable flow characteristics can be obtained up to high flow rate with excellent linearity.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In this example,
The idle rotation control device 15 has a core 18 and a plunger 19 arranged in the center of a cylindrical coil 17 and has a conical cross section between the opposing parts, so that the amount of electricity supplied to the solenoid coil 17 is set at a mechanical position. Solenoid 20 for conversion, body 22 having air passage or fluid passage 21 to be controlled, fluid passage 2
A valve body 29 is formed of a valve 25 for opening and closing 1,35 and a valve seat 23 with which the valve abuts, and a valve body 29 made of an elastic body such as rubber is attached to the tip of a shaft 28 fixed to one end of the plunger 19. Is provided, and the valve element 29 is arranged so as to abut the tip of the valve 25.

A spring 27 is arranged between the valve body 29 and the body 22, and is configured to balance with the electromagnetic force of the solenoid 20 to generate a stroke proportional to the input.

A passage 30 for pressure communication is provided at the axial center of the valve 25.
Further, the diaphragm 33 is fixed to the negative pressure side of the valve 25 via the diaphragm retainers 31 and 32 by the screw 34 to isolate the negative pressure passage 35. The isolated room is called diaphragm room 36.

The other end of the valve 25 extends to the diaphragm chamber 36 and covers it.
It is slidably supported by a support 38 provided on 37. On the other hand, an orifice 39 is provided on the shaft of the valve 25, the passage 30 and the diaphragm chamber 36 are communicated with each other, and the valve 25 slides,
The orifice 39 functions as a variable orifice whose area changes in cooperation with the support 38.

Further, the diaphragm 33 has a negative pressure passage 35 and a diaphragm chamber.
An orifice 40 communicating with 36 is provided, and these constitute a flow rate measuring mechanism section. Reference numeral 41 denotes an atmosphere communication hole that communicates the passage 21 with the room in which the valve element 29 is disposed, and 42 is a spring provided between the cover 37 and the diaphragm 33, which has a function for returning the diaphragm 33.

In such a structure, when the input to the solenoid 20 is 0 and a predetermined negative pressure is applied to the negative pressure passage 35, the plunger 19 does not operate and the valve element 29 is the tip of the shaft of the valve 25 as shown in FIG. And a gap 43 is formed apart from. Therefore passage 21
The atmosphere from is introduced into the diaphragm chamber 36 through the gap 43, the passage 30 and the orifice 39, and a predetermined differential pressure is generated at both ends of the diaphragm 33. Due to this pressure difference, the diaphragm 33 receives a force in the direction of the arrow 44.
The valve 25 fixed to the valve 25 also receives a force in the same direction, and the valve 25
Keeps close contact with the valve seat 23.

When a predetermined input of 0.3 A is applied to the solenoid 20, the plunger 19, the shaft 28, and the valve body 29 stroke the core 18 against the spring force of the spring 27. Then, the valve body 29 and the shaft of the valve 25 come into contact with each other, and the valve body 29 seals the passage 30.
When the passage 30 is sealed, the negative pressure from the negative pressure passage 35 enters the diaphragm chamber 36 through the orifice 40, so that the atmospheric pressure in the chamber 36 becomes negative pressure, and after a certain time, the negative pressure is reduced. It becomes equal to the negative pressure in the passage 35, and the differential pressure across the diaphragm 33 becomes zero.

As a result, the force in the direction of arrow 44 disappears, and the valve 25 receives the force in the direction of arrow 45 due to the pressure difference across the valve 25, and instantaneously moves in the direction of arrow 45.

When the valve 25 moves in the direction of the arrow 45, it separates from the valve element 29 again, so that a gap 43 is created, and the atmosphere is sucked from this gap 43, and the pressure in the diaphragm chamber 26 becomes atmospheric pressure via the passage 30. As a result, a force in the direction of arrow 44 acts on the diaphragm 33 and tries to push the valve 25 back.

When the plunger 19 and the valve body 29 reach the position proportional to the input to the solenoid 20, the above-mentioned repeated operation of the valve 25 becomes small, and the flow rate between the valve 25 and the valve seat 23 becomes a value corresponding to the input. To be weighed.

In this embodiment, as described above, the solenoid 20 performs linear electric-position conversion, the pressure is controlled by the position control, the driving force of the valve 25 operates the pressure difference of the valve itself, and This operating force is pressure-corrected by a correction mechanism composed of a diaphragm.

Next, the variable orifice 39 will be described in detail.

The size of the orifice 39 influences when the valve body 29 and the tip of the valve 25 shaft do not abut, that is, when the gap 43 exists.

Therefore, when the input is zero, if the orifice 39 is enlarged and a large force is applied to the diaphragm 33 in the direction of the arrow 44, the valve 25 comes into close contact with the valve seat 23, and the initial leakage at the time of zero input, that is, Fig. 2 a _{1 of} curve a is
Can be as small as a ₂ .

However, when the high input range is reached, the valve 29 causes the passage 30
If the opening area of the orifice 39 is large, the return force of the diaphragm 33 in the direction of the arrow 44 also increases, and the control flow rate per unit increases.
Hunting occurs as shown by a _{3 in} the curve a in FIG. 2 and the control becomes impossible.

From the above, it can be understood that it is desirable to continuously change the opening area of the orifice 39 in accordance with the stroke of the valve shaft.

In the embodiment of the present invention, the opening area of the orifice 39 is continuously variable by the support 38 as the axis of the valve 25 strokes.

As a result, a linear flow rate characteristic with a small initial leak as shown by the curve b in FIG. 2 is obtained.

In addition to these basic effects, by adopting a variable orifice, the correction force of the diaphragm can be changed according to the input to the solenoid, initial leakage is small, and stable flow rate characteristics with high linearity can be obtained. There is an effect.

〔The invention's effect〕

According to the present invention, the driving force of the valve for controlling the flow rate is driven by the pressure difference applied to the valve itself, and moreover, the correction force of the diaphragm can be changed according to the input to the solenoid coil. There is an effect that stable flow rate characteristics can be obtained up to the flow rate.

[Brief description of drawings]

FIG. 1 is a transverse sectional view showing a first embodiment of an idle speed control device of the present invention, and FIG. 2 is a flow rate characteristic diagram of the first embodiment of the present invention. 23 ... Valve seat, 25 ... Valve, 29 ... Valve body, 33 ... Diaphragm, 39 ... Variable orifice.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomio Ito 2520 Takaba, Takata, Ibaraki Pref., Sawa Plant, Hitachi Ltd. (72) Chiaki Niida 2520 Takata, Katsuta, Ibaraki Hitachi, Ltd. Sawa Factory (72) Inventor Takashi Iseyama 3085, Higashiishikawa Nishikonai, Katsuta City, Ibaraki 5 Hitachi Automotive Engineering Co., Ltd. (56) Reference JP 62-137480 (JP, A)

Claims (2)

[Claims] 1. A cylindrical solenoid coil for converting an input electric quantity into a position output, a core at the center of the solenoid coil and a plunger having a valve element inserted into the core at one end, and an intake pipe bypassed. A body that forms an air passage through which air flows, a valve that controls the flow rate of air that flows through the air passage in proportion to an electric signal that is input to the solenoid coil, and upstream and downstream sides of a valve seat that faces the valve. In a vehicle idle rotation control device that includes a diaphragm that is displaced according to the pressure difference and a diaphragm chamber for pressure correction that is formed by the diaphragm, the air passage on the upstream side of the seat and the diaphragm chamber. At the end of the communicating passage on the side of the diaphragm chamber, a variable valve whose opening area continuously changes according to the position of the valve. An idle rotation control device for an automobile, which is provided with a refill. 2. The idle rotation control device for an automobile according to claim 1, wherein the variable orifice is arranged so that an opening area thereof becomes smaller as a stroke of the valve becomes larger.