JPS6235877Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control valve for an exhaust gas recirculation system for an internal combustion engine for an automobile.

It is said that an exhaust gas recirculation device that recirculates the amount of exhaust gas in proportion to the amount of intake air is recommended from the viewpoint of vehicle drivability and fuel economy. One known exhaust gas recirculation device that is proportional to the amount of intake air is one that amplifies the negative pressure in the carburetor bench and performs exhaust gas recirculation in proportion to the negative pressure in the vent.

This will be explained according to FIG.

In Fig. 1, 1 is a carburetor, 2 is an engine,
3 is an exhaust gas recirculation valve, 4 is a control valve, 5 is an intake pipe, 6 is an exhaust pipe, 7 is an exhaust gas recirculation pipe, and 8 is a fixed orifice. EGR is connected to the exhaust recirculation valve 3 via the control valve 4.
Negative pressure acts from line 9. Further, the negative pressure of the carburetor bench from the pipe line 10 and the pressure of the control pressure chamber 11 between the fixed orifice 8 and the exhaust gas recirculation valve 3 act on the control valve 4 . Here, the exhaust gas recirculation valve 3 moves the valve 13 up and down depending on the balance between the magnitude of the EGR negative pressure and the load of the spring 12 to increase or decrease the cross-sectional area of the exhaust gas recirculation passage. The control valve 4 controls the pressure value of the EGR negative pressure acting on the exhaust gas recirculation valve 3 by opening and closing the seat portion 14 which is open to the atmosphere under the action of the carburetor vent valve negative pressure and the pressure of the control pressure chamber 11 .

In the device shown in FIG. 1, the pressure in the control pressure chamber 11 is controlled to a certain value depending on the engine speed and load.

This is because, if the pressure in the control pressure chamber 11 increases, the diaphragm assembly 15 of the control valve 4 moves upward so as to close the seat portion 14. Since the seat portion 14 is located within the atmospheric chamber 18, when this is closed, the EGR negative pressure acts directly on the negative pressure chamber 16 of the exhaust gas recirculation valve 3 without being reduced by the atmospheric pressure. At this time, the diaphragm 17 is connected to the spring 12.
The valve 13 moves upward against the force of , and the valve 13 moves to increase the cross-sectional area of the passage, so that the exhaust gas is recirculated and the pressure in the control pressure chamber 11 is reduced again. This cycle is repeated in response to engine exhaust pulsation, and as a result, the control pressure is controlled to a certain constant value.

Now, the control valve 4 used in this device has a structure as explained below.

In FIG. 2, the control valve 4 has an atmospheric chamber 18, a negative pressure chamber 19, an atmospheric chamber 20, and an exhaust pressure chamber 21 arranged in this order. A diaphragm 22 is disposed between the atmospheric chamber 28 and the negative pressure chamber 19, a diaphragm 23 is disposed between the negative pressure chamber 19 and the atmospheric chamber 20, and a diaphragm 24 is disposed between the atmospheric chamber 20 and the exhaust chamber 21.
A diaphragm 24 is provided between the diaphragms 22, 23, and 24. The diaphragms 22, 23, and 24 are fixed together at the center. A pipe 25 is connected to the EGR negative pressure line 9, and a pipe 26 is connected to the negative pressure chamber 16 of the exhaust gas recirculation valve 3.
The pipe 27 is connected to the carburetor ventilator through a rubber hose or the like. The pipe 27 is connected to the duct 10 which is connected to the carburetor ventilator.
This negative pressure acts on both diaphragms 22 and 23, but because the effective area of diaphragm 23 is greater than that of diaphragm 22, the combined force of the two diaphragms acts upward. The pressure of the control pressure chamber 11 acts on pipe 28. This control pressure is controlled to a negative pressure because there is a fixed orifice 8 as shown in Figure 1, and the negative pressure in the intake pipe of the engine acts on the passage 30 of the exhaust gas recirculation valve 3.
Thus, the diaphragm 24 exerts a downward force.

Since the three diaphragms 22, 23, 24 are fixed together at the center, the upward force generated by the two diaphragms 22, 23 and the downward force acting on the lower diaphragm 24 are balanced. Work as you see fit.

Here, if the combined effective area of the diaphragms 22 and 23 is made several times larger than the effective area of the diaphragm 24, the negative pressure in the exhaust pressure chamber 21 will be amplified several times as much as the negative pressure in the negative pressure chamber 19. Ru. Furthermore, as mentioned above, the pressure in the control pressure chamber 11 is controlled to a certain constant value, but since this pressure is the same as the pressure in the exhaust pressure chamber 21, the pressure in the control pressure chamber is several times the bench lily negative pressure. is controlled to a constant value that is amplified by

On the other hand, since the vent lily negative pressure increases in proportion to the intake air amount of the engine, the pressure in the control pressure chamber 11 also increases in proportion to the vent lily negative pressure.

The amount of exhaust gas recirculation is determined by the differential pressure generated before and after the fixed orifice 8 shown in Figure 1, but as the control pressure increases in proportion to the engine intake air amount as described above, the amount of exhaust gas recirculation depends on the amount of intake air. It will be proportional.

The control valve shown in FIG. 2 is indispensable in order to obtain an exhaust gas recirculation amount proportional to the amount of intake air. However, since this control valve uses three diaphragms, it has a complicated structure and also has disadvantages in terms of cost.

The present applicant has developed an exhaust gas recirculation amount control valve that reduces the number of diaphragms from three to two by one, and the applicant has filed Japanese Patent Application No. 51-138777 (Japanese Unexamined Patent Publication No. 53-64121).
It is proposed as.

In this exhaust gas recirculation amount control valve, a passage having an atmosphere opening for introducing the atmosphere into the exhaust gas recirculation valve extends into the atmospheric pressure chamber from the side of the body forming the atmospheric pressure chamber. In other words, a passageway having an atmosphere opening extends perpendicularly to the moving direction of the sheet that opens and closes the atmosphere opening.

Therefore, if this exhaust gas recirculation amount control valve is used for a long period of time, the passage forming the atmosphere opening will be damaged by the bending impact force when the seat collides with the atmosphere opening.

(If the passage is made of plastic, there is a risk of it breaking; if it is made of metal pipe, it may bend.)

Furthermore, since the members constituting each chamber are made of metal plates, there are problems such as increased weight and difficulty in sealing.

An object of the present invention is to provide an exhaust gas recirculation amount control valve which is lightweight, reduces the number of diaphragms, and does not damage the passage having an opening to the atmosphere.

The feature of the present invention is that by constructing it as described in the claims of the utility model registration, an atmospheric pressure chamber is formed between two diaphragms which are sandwiched with their outer peripheries kept airtight, and negative pressure is applied to each side of the chamber. A valve seat is installed on the atmospheric pressure chamber side of a diaphragm that forms a chamber and an exhaust pressure chamber, and partitions the atmospheric pressure chamber and exhaust pressure chamber, and the opening of the atmosphere introduction passage communicating with the atmospheric pressure chamber is adjusted according to the displacement of the diaphragm. In the exhaust gas recirculation amount control valve whose opening/closing is controlled by this seat, this atmospheric air introduction passage is formed on the extension of the movement axis of the seat across the negative pressure chamber, and this atmospheric pressure introduction passage is formed on the diaphragm on the negative pressure chamber side. It is located through the cover that holds the inner circumference.

As a result, the exhaust gas recirculation amount control valve according to the present invention can solve the conventional problem that the portion forming the atmosphere introduction passage is deformed by the impact caused by the collision of the seat.

Further, according to the present invention, the member forming the air introduction passage can also serve as a part of the member that airtightly clamps the inner peripheral edge of the diaphragm, which has the effect of reducing the number of parts.

Furthermore, since the atmosphere introduction passage can be formed in the space between the negative pressure chamber and the atmospheric pressure chamber, this type of control valve can be made smaller.

An embodiment of the present invention will be described with reference to FIG. In FIG. 3, 31 indicates a negative pressure chamber 40 and a holder 32.
It is a diaphragm formed together with the diaphragm. The outer periphery of this diaphragm 31 includes a holder 32 and a body 33.
The inner periphery is held by a holder 32 and a cover 34.
is held by. Further, the diaphragm 31 is held in the center by plates 35 and 36.

37 is an atmospheric chamber and a diaphragm plate 36
Since the hole 49 is provided in the air chamber 43, the atmospheric pressure is naturally maintained in the atmospheric chamber 43 as well. Reference numeral 38 denotes an exhaust pressure chamber, to which control pressure is applied via a pipe formed in the case 39. The atmospheric chamber 37 and the exhaust pressure chamber 38 are partitioned by a diaphragm 41 held between the body 33 and the case 39. A seat 42 is provided at the center of the diaphragm 41, and when the exhaust pulsation of the engine acts on the exhaust pressure chamber 38,
Opening and closing the inlet 56 of the pipe 46 within the atmospheric chamber 43
Controls EGR negative pressure. 44 is a soundproof stopper when the diaphragm assembly is activated.
Bench lily negative pressure is introduced into the pipe 45, and the negative pressure chamber 40 is introduced through the through hole 53 provided in the holder 32.
Bench lily negative pressure acts on. 47 and 48 are springs that adjust the control pressure of the control valve 4;
8 supports the weight of the diaphragm assembly and can be removed if the diaphragm weight is negligible. 52 is spring 4
This spring seat has a plurality of protrusions 54, and the protrusions 54 penetrate the cover 34 and are in contact with the adjuster plate 50. The nut 51 is connected to the adjuster plate 50 and the spring seat 52.
This adjusts the set load of the spring 47. Further, as shown in FIG. 4, the adjusting plate 50 has a rotation preventing portion 59 bent along the side surface of the nut 51 in order to prevent the nut 51 from rotating after the load of the spring 47 is set.
Additionally, an adjuster plate 5 is provided on the outer surface of the cover 34.
A rotation prevention protrusion 55 of 0 is provided. 57 is a filter, and 58 is an air vent.

According to the above configuration, the control valve 4 shown in FIG.
has the same function as the control valve 4 shown in FIG.

That is, the bench lily negative pressure acts on the negative pressure chamber 40, and the control pressure chamber 11 shown in FIG.
When this pressure is applied, an upward force is generated on the diaphragm 31, and a downward force is generated on the diaphragm 41. At this time, since the diaphragm 31 and the diaphragm 41 are mechanically connected by the plate 36, the ventilator negative pressure acting on both diaphragms and the pressure in the control pressure chamber 11 are compared with each other. Therefore, if the effective area of the diaphragm 31 is set to several times the effective area of the diaphragm 41, the vertical forces will be balanced when the control pressure reaches a value times the effective area ratio of the bench lily negative pressure. The diaphragm effective area ratio of the bench lily negative pressure can be amplified twice. Further, the seat portion 42 in FIG. 3 is configured to control the negative pressure acting on the exhaust gas recirculation valve 3 in the atmosphere by turning on and off the inlet 56 of the pipe 46, similarly to the control valve in FIG.

Therefore, according to the present invention, even if the number of diaphragms is reduced from three to two, the function of amplifying the negative pressure of the carburetor vent lily and controlling the on/off of the inlet 56 of the pipe 46 can be maintained in the same way as the conventional control valve. can have.

Furthermore, in the control valve shown in FIG. 3, a holder 32, a body 33, a cover 34, a case 3
9. It is also possible to mold members such as the spring seat 52 using plastic material and assemble them using techniques such as ultrasonic welding. If a plastic material is used, in addition to the weight reduction achieved by changing the structure from FIG. 2 to FIG. 3, it is possible to further reduce the weight and further reduce the price.

Regarding the size, the present invention can definitely be smaller than the one shown in FIG. The reason is that although the conventional product shown in FIG. 2 has a negative pressure chamber 19,
Both diaphragms 22 and 23 are used. 2
The combined force of the two diaphragms is generated upward as described above, but since the diaphragm 22 generates a downward force when negative pressure is applied to the negative pressure chamber 19, the diaphragm 23 that generates the upward force is It has no choice but to become larger. However, the product of the present invention shown in FIG. 3 has the advantage that the diaphragm 31 can be made more compact than the conventional embodiment because the diaphragm 31 acts quite effectively to generate upward force.

Further, the present invention has the advantage that adjustment of the operating pressure of the control valve is easier. This is because the position of the spring seat 52 can be freely adjusted by moving the nut 51 up and down.

As described above, according to the present invention, the number of diaphragms can be reduced, the size and weight can be reduced, and as a result, a product can be provided at a low price.

Although the above explanation has been made with respect to a system using a carburetor, the control valve according to the present invention can also be applied to other systems using negative pressure corresponding to the carburetor bench pressure.

In addition, in FIG. 2, there are two pipes 25 and 26, but in the case of the present invention, pipe 46 is provided.
By providing a T-shaped connector at the end of the connector, it is possible to create a system equivalent to the conventional system.

[Brief explanation of the drawing]

Figure 1 is an explanatory configuration diagram of the exhaust gas recirculation system, Figure 2
3 is a sectional view of a control valve according to the present invention, and FIG. 4 is a top view of the control valve according to the present invention. 31...Diaphragm, 32...Holder, 3
3...Body, 34...Cover, 35...Plate, 37...Atmospheric pressure chamber, 38...Exhaust pressure chamber, 39...
...Case, 43...Atmospheric chamber.

Claims (1)

[Claims for Utility Model Registration] (a) Mounted so that its outer periphery is sandwiched between a synthetic resin body and a synthetic resin holder, and its inner periphery passes through the center of said holder. a first diaphragm sandwiched between the holder and the first diaphragm; (b) a negative pressure chamber formed by the holder and the first diaphragm and into which the negative pressure of the carburetor's bench lily or an equivalent negative pressure is introduced; ) a second diaphragm held between the body and a synthetic resin case; (d) an atmospheric pressure chamber formed between the first diaphragm and the second diaphragm; (e) the (f) a plate disposed in the atmospheric pressure chamber and fixedly connecting the first diaphragm and the second diaphragm; (f) formed on the cover attached by passing through the center of the holder and the first diaphragm; (g) an atmosphere introduction passageway having one end open to the atmospheric pressure chamber and the other end connected to a conduit that sends a negative pressure signal to the negative pressure chamber of the exhaust recirculation valve; (h) a compression spring that biases the diaphragm away from the opening of the atmosphere introduction passageway to the atmospheric pressure chamber; a seat member that opens and closes; (i) an exhaust pressure that is formed by the second diaphragm and the case and leads to the pressure between the valve body of the exhaust gas recirculation valve provided in the exhaust gas recirculation passage and an orifice provided upstream thereof; (j) a compression spring provided between an inner wall of the exhaust pressure chamber and the second diaphragm so as to oppose a compression spring in the atmospheric pressure chamber.