JPH0713504B2 - Method for improving valve characteristics of engine idle speed control valve - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control valve for controlling idling of an internal combustion engine of an automobile, and more particularly to a method for improving valve characteristics at the time of starting. .

[Conventional technology]

FIG. 4 is a sectional view of a conventional idling speed control valve.

When the electromagnetic coil (hereinafter referred to as coil) 6 is energized, the plunger 1 is attracted to the left in the figure.

The shaft 2 is fixed to the plunger 1 and is urged rightward in the drawing by a spring 7.

Reference numeral 3 denotes a core of the coil 6, which holds an adjusting screw 4 that regulates the stroke of the shaft 2. 5 is an O-ring.

The end face of the plunger 1 (the end face on the right side in the drawing, which is a concave face in this example, the end face is not necessarily a flat face in the present invention) is attached to the pilot valve seat via the shaft 2. 9 is provided.

Reference numeral 8 is a spring that biases the plunger 1 to the left in the drawing.

A hollow shaft 10 is formed separately from the above, and is supported concentrically with the plunger 1 so as to be slidable in the axial direction.

The right end of the hollow shaft 10 shown in the drawing opens into a chamber 22 in the case 17, and this chamber 22 is communicated with the carburetor throttle unit downstream of the throttle valve. Reference numeral 18 is a guide for the hollow shaft 10.

A main valve 13 is fixed to the hollow shaft 10, and the main valve 13 is arranged between the chamber 22 and a chamber 21 communicating with the upstream side of the throttle valve.

A diaphragm 11 is attached to the hollow shaft 10 via a plate 12.

The diaphragm 11 includes a chamber 21 and a diaphragm chamber 20.
And are partitioned. The diaphragm chamber 20 communicates with the atmosphere via the orifice 14.

A pilot valve 15 is provided at the left end of the hollow shaft 10 in the figure.
Are formed. The pilot valve 15 is located in the diaphragm chamber 20 and faces the pilot valve seat 9 described above.

The operation of this conventional idle speed control valve will be described below.

At the time of starting, when the coil 6 is not energized, the plunger 1 is pushed to the right side in the drawing by the balance between the spring 7 and the spring 8, and the plunger 1 is stopped by the contact between the pilot valve seat 9 and the pilot valve 15. . In this state, the pilot valve 15 is fully closed and the diaphragm chamber
20 is at atmospheric pressure through the orifice 14. The chamber 21 which is the air inflow side to the case 17 is also close to the atmospheric pressure,
Therefore, there is almost no differential pressure across the diaphragm 11, and no force is generated in the diaphragm 11. The differential pressure before and after the main valve 13 is the differential pressure between the chamber 21 and the chamber 22 due to the suction negative pressure of the engine in the chamber 22 on the air outflow side. This value is about 500 mmHg in the normal idling state, which is the force in the valve closing direction of the main valve 13.

When the coil 6 is energized and excited, a magnetic field is generated and an attractive force of the plunger 1 is generated. This suction force moves the plunger 1 to the left, and the pilot valve seat 9 separates from the pilot valve 15.

By the above separating operation, the negative pressure on the downstream side of the throttle valve is communicated with the inside of the diaphragm chamber 20, and the diaphragm 11 is pushed to the left in the drawing.

In this way, the hollow shaft 10 and the main valve 13 fixed thereto are driven by the plunger 1 while being boosted by the differential pressure applied to the diaphragm 11.

[Problems to be Solved by the Invention]

In the above-mentioned conventional example (FIG. 4), when the starting rotation speed is low, for example, during low temperature starting, a sufficient pressure difference is not generated between the chamber 21 and the diaphragm chamber 20. The valve opening force of the main valve 13 is insufficient, and the desired idling speed control characteristic cannot be obtained.

Further, the battery capacity decreases at the time of cold start, and the coil 6
Since the amount of electricity to the main valve 13 tends to be insufficient and the electromagnetic attraction force of the plunger 1 is insufficient, the opening degree of the main valve 13 is further insufficient.

If the opening is insufficient, a proper fuel-air ratio cannot be obtained and the start fails.

The present invention has been made in view of the above circumstances, and provides a method for improving the valve characteristics of an idle speed control valve so as to be suitable for a cold start in order to eliminate the difficulty in starting at a cold start. It is what

Conventionally, as a low temperature measure for the idle rotation control valve,
To prevent icing, a flow control valve has been proposed which is configured so that the main valve is kept in a slightly opened state when de-energized (Japanese Patent Laid-Open No. 56-56).
-120872). However, an invention and a device for improving the valve characteristic at the time of starting have not been proposed yet.

[Means for Solving the Problems]

The method of the present invention created to achieve the above object is
For the main valve of the idling speed control valve,
Apply force in the valve opening direction.

Needless to say, the above-mentioned force does not give a large force that disturbs normal operation, but is a force sufficient to compensate for the valve opening force that is insufficient at low temperature starting.

Compared with the above-mentioned known technique (Japanese Patent Laid-Open No. 56-120872), in order to prevent icing, the spring force is balanced so as to keep the main valve in a slightly opened state when de-energized. One-way, a weak force in the valve opening direction (valve opening assisting force) is always applied.

Further, the idle speed control valve of the present invention created for carrying out the above method is provided with a means (for example, a compression coil spring) for applying a force in the valve opening direction to the main valve. In this case, the force in the valve opening direction is a one-way assisting force, and does not have a configuration that attempts to regulate the main valve position by balance.

[Work]

At the time of cold start, the battery capacity decreases, the torque of the starter motor decreases, and the viscosity of the lubricating flow increases and the starting rotation speed decreases. For this reason, the differential pressure applied to the diaphragm of the idle speed control valve decreases, and the valve opening force becomes insufficient.

Further, due to the decrease in the battery capacity, the electromagnetic attraction force of the coil becomes insufficient and the valve opening force becomes even more insufficient.

When the above-described method of the invention is applied here to apply an assisting force in the valve opening direction, the valve opening operation is assisted and accelerated to open the main valve, and the required combustion air is supplied.

In the idle speed control valve of the present invention, a force in the valve opening assisting direction is constantly applied by, for example, a compression coil spring, so that the insufficient valve opening force at low temperature start-up is compensated for and an appropriate combustion air flow rate is obtained. Therefore, a proper fuel-air ratio is obtained, and the success rate of starting is significantly improved.

〔Example〕

FIG. 1 was constructed by applying the valve characteristic improving method according to the present invention. It is sectional drawing which shows one Example of the idle speed control valve of this invention.

This embodiment is an improvement in which the present invention is applied to the conventional example shown in FIG. 4, and those having the same drawing reference numerals as the above-mentioned conventional example are the same as or similar to those in the conventional example. Is a constituent part of.

Next, differences from the conventional example (FIG. 4) will be described.

A coil spring 16a is configured to be interposed between the main valve 13 and the case 17 by compression so as to urge the main valve 13 in the valve opening direction (to the left in the drawing).

Although the valve opening force at the time of low temperature starting tends to be insufficient for the above-mentioned reason, if the valve opening force insufficient at the time of low temperature starting is assisted by the coil spring 16, the main valve 13 can be opened even at the time of low temperature operation. Become.

FIG. 2 is a valve characteristic chart in which the horizontal axis represents the energization amount of the coil 6 and the vertical axis represents the opening stroke of the main valve 13 in this embodiment.

This chart shows three lines with the negative pressure on the downstream side of the throttle valve as a parameter, which corresponds to idling rotation under normal conditions.
The solid line shows Kpa (gauge pressure), and the broken line shows -27 Kpa (gauge pressure) corresponding to the starting operation under normal conditions.

The chain line shows Opa, which means the extreme state at low temperature and bad starting conditions.

As is clear from this chart, in the idle speed control valve of this embodiment, the suction differential pressure is extremely low (Opa).
In the case of, even if a current is applied to the coil 6, the pilot vibrator 15 is opened by the operation of the plunger 1, and even if the differential pressure applied to the diaphragm 11 is small, the main valve 13 is easily opened by the auxiliary force of the coil spring 16a and the pilot valve Since the main valve 13 is opened by opening the valve 15, the opening of the main valve 13 increases in proportion to the current of the coil 6.

For this reason, the engine can be started even at low temperatures, and it is possible to prevent a failure in starting due to insufficient intake air flow rate.

FIG. 3 shows an embodiment different from the above. The difference from the previous example (Fig. 1) is that the coil spring 16b is configured,
That is, compression is interposed between the case 17 and the diaphragm 11 (specifically, between the plate 12 supporting the diaphragm 11). Also in this example, the same actions and effects as in the previous example can be obtained.

〔The invention's effect〕

As described above, when the idle speed control valve of the present invention is configured by applying the improvement method of the present invention, suitable valve characteristics can be obtained at low temperature starting, and an appropriate intake air amount can be obtained even at low temperature starting conditions. Therefore, a proper fuel-air ratio can be obtained, and it is possible to prevent a start failure due to an inappropriate fuel-air ratio.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an idle speed control valve according to the present invention. FIG. 2 is a chart for explaining the operation and effect of the above embodiment. FIG. 3 is a sectional view of an embodiment different from the above. FIG. 4 is a cross-sectional view of a conventional idle speed control valve. 1 ... Plunger, 6 ... Coil, 9 ... Pilot valve seat, 10 ... Hollow shaft, 11 ... Diaphragm, 13 ... Main valve, 14 ... Orifice, 15 ... Pilot valve, 16a, 16b ...... Coil spring.

Claims (4)

[Claims] 1. An electromagnetic coil, a plunger that is attracted by the electromagnetic coil, a spring that acts on the plunger to balance the attractive force of the electromagnetic coil, and a pilot valve provided on the end face of the plunger. A seat, a hollow shaft formed separately from the plunger and having a main valve and a diaphragm fixed to each other, and a pilot valve that is formed at one end of the hollow shaft and faces the pilot valve seat. A pilot valve slidably supported in the axial direction and formed at one end of the hollow shaft is located in a chamber that is in contact with the diaphragm and communicates with the atmosphere through an orifice. The end opposite to the pilot valve is connected to the downstream side of the throttle valve. A method for improving the valve characteristics of an idle speed control valve in which a pilot valve is opened by a runner to open a main valve by a diaphragm, and a valve opening force at a low temperature start is applied to the main valve. A valve characteristic improving method for an idle speed control valve of an engine, which is characterized by constantly applying a force in a valve opening direction sufficient to compensate for the shortage of the engine. 2. The engine idler according to claim 1, wherein the force for compensating for the insufficient valve opening force is given to the main valve or a member fixed thereto by a restoring force of a spring. Method for improving valve characteristics of speed control valve. 3. The engine according to claim 1, wherein the force for compensating for the lack of the valve opening force is given by a coil spring interposed between the case of the control valve and the main valve. Method for improving valve characteristics of idle speed control valve. 4. The engine idler according to claim 1, wherein the force for compensating for the lack of the valve opening force is provided by a coil spring compression-inserted between the case of the control valve and the diaphragm. Method for improving valve characteristics of speed control valve.