JPS6234995B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a flow control valve.

An exhaust gas recirculation system (EGR system) has been proposed as a means of removing nitrogen oxides (NOx), which are among the harmful components produced in the combustion chamber of an internal combustion engine, by circulating a portion of the exhaust gas back into the intake manifold and re-burning it. However, this exhaust recirculation system
Generally, an exhaust gas recirculation control valve (EGR valve) is placed between the exhaust pipe and the intake manifold, and this control valve is operated according to negative pressure fluctuations in the intake system to control the recirculation of exhaust gas to the intake manifold. However, the timing and amount of recirculation of exhaust gas to the intake manifold have a strong influence on exhaust purification efficiency, output, and drivability, so it is important to operate the exhaust recirculation control valve accurately. is strongly desired.

In order for this exhaust gas recirculation control valve (EGR control valve) to work correctly, the intake manifold and
It is conceivable that an air flow control valve is disposed between the EGR control valve and the EGR control valve is opened and closed by this air flow control valve. This type of air flow control valve is disclosed, for example, in Japanese Unexamined Patent Publication No. 53-20033, that is, as shown in FIG.
2, the input port 44 and the output port 51 are communicated with each other, and the fluid introduction port 31 is connected to this communication path.
Atmospheric air is introduced from the air through an orifice 39, and a valve S that operates in response to a signal negative pressure is disposed in the introduction path. Therefore, when the signal negative pressure is large and the valve is closed, the negative pressure from the input port 44 is directly connected to the output port 51, and the pressure at the input port becomes equal. Therefore, in order to make the large constant value of the exhaust gas recirculation amount variable, it is necessary to change the characteristics of the servo means (EGR control valve). This impairs the versatility of the servo means. Therefore, in the present invention, a circuit as shown in FIG. 6 is used, and the output pressure when the signal negative pressure is small and the exhaust gas recirculation amount is large is
The purpose of this invention is to make it possible to vary the large constant value of the amount of exhaust gas recirculation by changing the orifices 18, 21, and 26. this is,
A large constant value of the amount of exhaust gas recirculation can be made variable without changing the characteristics of the servo means.

According to the present invention, in order to achieve the above object, a first negative pressure chamber and an atmospheric pressure chamber defined by a swinging member in the housing, and a second negative pressure chamber facing the atmospheric pressure chamber are provided. and the second negative pressure chamber is arranged in parallel with a first passage passing through the first orifice to the output port of the housing and the first passage, and the valve member and the second orifice are connected in series. The swinging member swings in its axial direction in response to the negative pressure in the intake manifold introduced into the first negative pressure chamber, and the movement of the swinging member is The valve member is opened and closed by a rod fixed to the swinging member, and the second negative pressure chamber is connected to the EGR port of the carburetor and the output port is connected to the EGR port.
A flow control valve is provided that is characterized in that it communicates with a control valve.

Embodiments of the invention will be described with reference to the accompanying drawings.

The flow control valve 1 has a first negative pressure chamber 5 defined by a diaphragm 4 held between a housing 2 and a cover 3 and an atmospheric pressure 6 . The diaphragm 4 includes a swinging member 9 which is biased in one direction by a spring 7 and carries a rod 8. The first negative pressure chamber 5 communicates with an intake manifold 10 . A cap 11 is fixed to the housing 2,
A second negative pressure chamber 12 is defined. Second negative pressure chamber 1
2 communicates with the EGR port 13 and, via the first orifice 21, with the output port 20, for example. A valve member 16 biased by a spring 15 is housed within a bore 14 formed in the cap 11 . This valve member 16 is in contact with the tip of the rod 8 and can be seated on the seat 17. A second orifice 18 is disposed in the bore 14, and the second negative pressure chamber 12 can be communicated with the output port 20 via the valve 19 and the second orifice 18. The output port 20 communicates with a negative pressure chamber 23 of the EGR control valve 22. A passage 24 connecting the output port 20 and the negative pressure chamber 23 is an intake air passage 25.
and is connected via a third orifice 26.
The EGR control valve 22 controls communication between the exhaust pipe 27 and the intake manifold 10 using a valve member 28.

The flow control valve 1 having the above-mentioned configuration is configured such that when the negative pressure in the intake manifold 10 is small, the diaphragm 4
The rod 8 moving therewith pushes the valve member 16 and puts the second negative pressure chamber 12 into communication with the output port 20 through the second orifice 18 . Thus, EGR
The port 13 is in communication with the negative pressure chamber 23 of the EGR control valve 22 via the two orifices 18 and 21, and the amount of exhaust gas recirculation determined by the two orifices 18 and 21 and the third orifice 26 is obtained. . In fact, when the negative pressure in the intake manifold 10 is low, a large amount of exhaust gas can be recirculated.

Furthermore, when the negative pressure in the intake manifold 10 increases, the diaphragm 4 moves against the biasing force of the spring 7, seats the valve member 16 on the seat 17, and causes the second valve to open via the second orifice 18. Communication between the negative pressure chamber 12 and the outlet port 20 is cut off.
Thus, the negative pressure chamber 23 of the EGR control valve 22 communicates with the second negative pressure chamber 12 only through the second orifice 21, and the negative pressure chamber 23 of the EGR control valve 22 communicates with the second negative pressure chamber 12 only through the second orifice 21.
1, 26, a small amount of exhaust gas recirculation is achieved.

As is clear from the above, the flow control valve of this example can vary the amount of supplied air flow in response to changes in negative pressure in the intake system of an internal combustion engine, and enables optimal exhaust gas recirculation. .

FIG. 2 shows another example of the air flow control valve 1'.
In FIG. 1, the valve member 16 is disposed within the bore 14, but
In this example, a spring 15 is provided in the space between the annular wall 27 of the housing 2 and the projecting wall 28 of the cap 11.
A plate-shaped valve member 16' biased by
The valve member 16' opens and closes the port 29 of the bore 14, and the second
The communication between the negative pressure chamber 12 and the output port 20 is controlled. In this example as well, the effects described in connection with FIG. 1 can be similarly obtained.

The example 1a shown in FIG. 3 differs from the example shown in FIG. 2 in that one is a fixed orifice 21 while the other is a needle valve 30. A passage 32 is formed in the sleeve 31 screwed into the bore 14, and one end of this passage 32 is
It is conical in shape. In this conical part, the tip of a needle 33 fixed to a valve member 16' biased by a spring 15 is located, and in response to the movement of the valve member 16' cooperating with the rod 8, the output port 2
0 and the second negative pressure chamber 12 are changed. The sleeve 31 is screwed into the bore 14, so by rotating the sleeve 31, the needle 3
The relative position to 3 can be adjusted. Example 1b shown in FIG. 4 is an example 1b in which only the needle valve 30 is used without using the fixed orifice 21.
A needle 33 fixed to the valve member 16' cooperating with the rod 8 is positioned with its tip at the conical end of the passage 32 of the sleeve 31 screwed into the bore 14, and the movement of the valve member 16' Needle 3 depending on
3, the degree of communication between the output port 20 and the second negative pressure chamber 12 can be adjusted.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an exhaust gas recirculation system incorporating a flow control valve according to one example of the present invention, FIG. 2 is a sectional view showing another example, FIG. 3 is a sectional view showing another example, and FIG. 4 is a sectional view showing another example. The figure is a sectional view showing yet another example, FIG. 5 is a basic circuit diagram of a conventional example, and FIG. 6 is a circuit diagram showing the principle of the present invention. In the figure: 1, 1'... Air flow control valve, 4... Diaphragm, 5, 12... Negative pressure chamber, 6... Atmospheric pressure chamber, 8... Rod, 16, 16'... Valve member, 1
8, 21...orifice, 20...exit port.

Claims (1)

[Claims] 1 has a first negative pressure chamber and an atmospheric pressure chamber defined by a swinging member in the housing, and a second negative pressure chamber facing the atmospheric pressure chamber, and the second negative pressure chamber is connected to the housing. a first passage passing through a first orifice to the outlet port of the oscillator, and communicating with the first passage through a second passage arranged in parallel and having a valve member and a second orifice in series; The member swings in its axial direction in response to the negative pressure in the intake manifold introduced into the first negative pressure chamber, and the movement of the swinging member causes the valve to be moved by a rod fixed to the swinging member. 1. A flow control valve, which is opened and closed, and the second negative pressure chamber communicates with an EGR port of a carburetor, and the outlet port communicates with an EGR control valve.