JPH03286152A - Exhaust control valve for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the energizing sealing performance by arranging a sealing member between a valve body and at least either the first or second valve seat and blowing exhaust gas so that the part between the valve body and the valve seat is closed in perfect closure of an exhaust passage. CONSTITUTION:The first and second valve seats 24 and 25 are formed on the side edge surfaces of a valve passage 21 opposed to the upper and lower projection parts 22 and 23 in the valve body 20 of an exhaust control valve 9, and the first and second rings 29 and 30 are inserted into the annular first and second ring grooves 26 and 27 over nearly half the circumference. In the perfect closure state, the first sealing surfaces 29a (30a) of the first and second rings 29 and 30 are closely attached to the peripheral edge part on each side surface of a valve body 15, and energized against the valve body 15 by the force FH based on the pressure FG of exhaust gas, and the second sealing surfaces 29b (30b) are energized against the projecting parts 28 and 31 by each force FV. Accordingly, the sealing performance between the valve body 15 and the valve seats 24 and 25 can be improved without increasing the working precision and assembly precision of the valve body 15, valve seats 24 and 25, and the valve shaft 16.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an exhaust control valve for an internal combustion engine.

[Conventional technology]

Japanese Utility Model Application Publication No. 60-69339 discloses that a valve body rotatable around a valve shaft is disposed in an exhaust passage, and a first seat is provided on which a substantially semicircular peripheral edge on one side of the valve body can be seated. The valve seat and a second valve seat are seatable on a substantially semicircular peripheral edge of the other side of the valve body, and are disposed at a position symmetrical to the second valve seat with respect to the valve shaft. discloses an exhaust control valve for an internal combustion engine in which an exhaust passage is opened and closed by a valve body.

In this exhaust control valve, the peripheral edge of one side of the valve body is the first
The exhaust passage is completely closed by the valve body by seating the second valve seat on the second valve seat and having the peripheral edge portion on the other side of the valve body sit on the second valve seat.

[Problem to be solved by the invention]

However, in this exhaust control valve, the processing accuracy and assembly of the valve body, valve seat, valve stem, etc. may vary due to variations in accuracy, or due to thermal distortion at high temperatures due to exposure to exhaust gas, for example, one side of the valve body may be damaged. When the peripheral edge of the side surface is seated on the first valve seat, the peripheral edge of the other side of the valve body cannot be seated on the second valve seat, and a gap is created between them, reducing sealing performance. There is a problem with doing so. In particular, since exhaust gas has a high pressure, the existence of such a gap causes a particular problem because a large amount of gas flows out.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, a valve body rotatable around the valve shaft is disposed in the exhaust passage, and one side of the valve body is provided with a first valve seat that can be seated, and a second valve seat that can be seated on the other side thereof, and the exhaust passage for an internal combustion engine is completely closed by the valve body being seated on the first valve seat and the second valve seat. In the valve, a seal member is disposed between the valve body and at least one of the first valve seat and the second valve seat, and the seal member is arranged between the first valve seat and the second valve seat when the exhaust passage is fully closed. The valve body is biased by exhaust gas pressure to close the space between at least one of the valve seats and the valve body.

[For production]

The sealing member is urged by exhaust gas pressure to close the space between the valve seat and the valve body when the exhaust passage is fully closed.

〔Example〕

FIG. 13 is an overall schematic diagram of the two-stage turbo internal combustion engine. Referring to FIG. 13, 1 is the engine body, 2 is an exhaust passage, 3 is an intake passage, and 4 is an intercooler. A small-capacity high-pressure turbine 5 and a large-capacity low-pressure turbine 6 are arranged in the exhaust passage 2 from the upstream side. The exhaust passage 2 is formed with a high-pressure stage bypass passage 7 and a low-pressure stage bypass passage 8, which bypass the high-pressure stage turbine 5 and the low-pressure stage turbine 6, respectively. An exhaust control valve 9 is disposed in the middle of the high pressure stage bypass passage 7, and a waste gate valve 10 is disposed in the middle of the low pressure stage bypass passage 8.

On the other hand, in the intake passage 3, a small-capacity high-pressure compressor 11 and a large-capacity low-pressure compressor 12 are arranged, which are driven by a high-pressure turbine 5 and a low-pressure turbine 6, respectively. An intake bypass passage 13 that bypasses the high-pressure compressor 11 is formed in the intake passage 3, and an intake bypass valve 14 is disposed in the intake bypass passage 13.

The opening degree of the exhaust control valve 9 is controlled according to the discharge pressures of the high-pressure compressor 11 and the low-pressure compressor 12. When the exhaust control valve 9 is fully closed, all the exhaust gas passes through the high pressure turbine 5.

FIG. 1 shows a longitudinal sectional view of the exhaust control valve 9 of the first embodiment. Referring to FIG. 1, a valve passage 21 is defined within the valve body 20. As shown in FIG. The valve passage 21 forms a part of the high-pressure stage bypass passage 7, is upstream on the left side in Fig. 1, and is connected to the engine main body 1 (see Fig. 13).The central part of the valve passage 21 in the six axis directions In 21a, the valve passage 21 has a cylindrical shape, and therefore, this central part 21a is called a cylindrical part.An upper protrusion 822 is formed on the upper surface of the inner periphery of the valve passage 21 on the left side of the cylindrical part 213. A lower protrusion 23 is formed on the lower surface of the inner periphery of the valve passage 21 on the right side of the valve passage 21a.A disc-shaped valve body 15 is arranged in the valve passage 21 so as to be rotatable around the valve shaft 16. This valve body 15 is located in the cylindrical part 21a when fully closed.The diameter of the valve body 15 is equal to the diameter of the cylindrical part 21a.
Since it is slightly smaller than the inner diameter of a, there is a gap between the outer circumference of the valve body 5 and the inner circumference of the cylindrical portion 21a when the valve body 15 is fully closed.

FIG. 2 shows a right side view of the valve body 20 shown in FIG. 1. Referring to FIGS. 1 and 2, the upper protrusion 2
2 is an annular shape slightly shorter than a semicircle, and has a lower protrusion 23
It is also circular, slightly shorter than a semicircle.

Further, the cross-sectional shapes of the upper protrusion 22 and the lower protrusion 23 perpendicular to the axis A of the valve passage 21 are formed symmetrically with respect to the axis A. Therefore, as shown in FIG. 2, a valve shaft gap 19 is formed between the lower end 22a of the upper protrusion 22 and the upper end 23a of the lower protrusion 23.

A first valve seat 24 and a second valve seat 25 are formed on opposing side end surfaces of the upper protrusion 22 and the lower protrusion 23, respectively. As shown in FIG. 1, the first valve seat 24 and the second valve seat 25 are formed on a first plane P1 and a second plane P2 perpendicular to the axis A of the valve passage 21, respectively. A gap equal to the thickness of the valve body 15 is provided between the first valve seat 24 and the second valve seat 25 in the direction of the axis A. Therefore, when the valve body 15 is fully closed,
Both side surfaces of the valve body 15 are a first plane P1 and a second plane P, respectively.
It is arranged so that it is located above 2. Therefore, as shown in FIG. 1, when the valve body 15 is fully opened, the valve body 15
The angle (valve opening angle) α between the center line B of the valve passage 21 and the axis A of the valve passage 21 is 90 degrees. The axis of the valve shaft 16 passes through the intersection of the axis A and the center line B and is perpendicular to them.

The valve stem 16 is shown in FIGS. 3 and 4. FIG. A recess 16a is formed at one end of the valve shaft 16. The width of this recess 16a is equal to the plate thickness of the valve body 15, and the valve shaft 16 is attached to the valve body 15 by fitting the valve body 15 into this recess. The other end of the valve shaft 16 has a small diameter portion 16b and a recessed portion 16a.
A large diameter portion 16C is formed between the small diameter portion 16b and the small diameter portion 16b.

FIG. 5 shows a right side view of FIG. 1. As shown in FIG. 5, the valve body 15 has two valve shafts 1 attached to both ends thereof.
6 on the valve body 20.

Referring to FIGS. 1 and 5, the outer circumference of the valve stem 16 is
It contacts the lowermost end of the first valve seat 24 and the uppermost end of the second valve seat 25, thereby preventing leakage around the valve shaft 16.

By the way, in the exhaust control valve in which the peripheral edges of both side surfaces of the valve body 15 are seated on the first valve seat 24 and the second valve seat 25, respectively, to close the valve passage 21, the valve body 15 , the machining accuracy and assembly of the first and second valve seats 24 and 25 and the valve stem 16 may be affected due to variations in accuracy, or due to thermal distortion at high temperatures due to exposure to exhaust gas, for example, on one side of the valve body 15. When the peripheral edge of the valve body 15 is seated on the first valve seat 24, the peripheral edge of the other side of the valve body 15 is seated on the second valve seat 24.
5 cannot be seated, and a gap is generated between them, resulting in a problem that the sealing performance is deteriorated. In particular, since exhaust gas has a high pressure, if such a gap exists, a large amount of exhaust gas will flow out, resulting in the problem that a sufficient amount of exhaust gas cannot be supplied to the high-pressure stage turbo 5 shown in FIG. 13. will occur.

Therefore, in the present invention, a ring serving as a sealing member is disposed between the valve body 15 and the valve seats 24 and 25.

Referring to FIG. 2, the first valve seat 24 is
A first ring structure 26 is formed in an annular shape and extends approximately semicircumferentially along the second valve seat 25 .
A second ring groove 27 is formed in an annular shape, extending along approximately a semicircumference. The first ring groove 26 is the first valve seat 2
4, and the second ring groove 27 also ends just before the uppermost end of the second valve seat 25.

FIG. 6 shows an enlarged view of the first ring groove 26. Referring to FIGS. 1 and 6, an annular projection 28 is formed at the opening of the first ring groove 26. As shown in FIG.

This protrusion 28 terminates immediately before both ends of the first ring groove 26, and therefore no protrusion 28 is formed near both ends of the first ring groove 26. A first ring 29 is inserted into the first ring groove 26 . The width W of the first ring groove 26 is about 1.5 times the width WR of the first ring 29,
Even when the two first rings are attached, there is a considerable gap in the first ring groove 26. The width Wp of the protrusion 28 is approximately ⅓ of the width W of the first ring. 2nd ring groove 2
7 is also formed in substantially the same manner, and has a protrusion 31 formed therein.

The first ring 29 is shown in FIGS. 7-9. The first ring 29 has a substantially semicircular annular shape, and is made of a soft metal such as a copper-based alloy, for example. The radius of curvature of the center line of the first ring 29 is larger than the radius of curvature of the center line of the first ring groove 26 . The first ring 29 has a first sealing surface 29a.
and a sealing portion 29c having a second sealing surface 29b;
The pressure receiving portion 29e has a plurality of notches 29d formed therein. The first sealing surface 29a and the second sealing surface 29b form a right angle as shown in FIG.
It engages with the protrusion 28 of the ring groove 26. The pressure receiving part 29e is formed to be higher than the sealing part 29c by the same height as the height of the projection part 28. End surface 29 of pressure receiving part 29e
f is inclined diagonally downward to the right. Therefore, end face 2
When the exhaust gas pressure Fc acts perpendicularly to 9f, a force Fn that urges the first ring 29 to the right and a force F that urges the first ring 29 upward act.

When inserting the first ring 29 into the first ring groove 26, the first ring 29 is inserted from the center into the first ring groove 26 while deforming so that both ends of the first ring 29 approach each other. . As mentioned above, since the radius of the center line of the first ring 29 is larger than the radius of the center line of the first ring groove 26,
The first ring 29 is stopped such that the outer periphery of the first ring 29 contacts the outer periphery of the first ring groove 26 . At this time, the pressure receiving part 29e of the first ring 29 is locked by the protrusion 28 of the first ring groove 26, so that the first ring 29 is prevented from falling off from the first ring groove 26. .

Referring to FIGS. 1 and 5, the second ring groove 27 is also formed in substantially the same manner as the first ring groove 26, and the second ring 30 is inserted into the second ring groove 27.

The second ring 30 is shown in FIGS. 10-12. Second
The ring 30 has a substantially semicircular annular shape, and is made of a soft metal such as a copper-based alloy, for example. The radius of curvature of the center line of the second ring 30 is smaller than the radius of curvature of the center line of the second ring groove 27 . The second ring 30 is the first sealing surface 30
a and a second sealing surface 30b.
and a pressure receiving part 30e in which a plurality of cuts 30d are formed. The first sealing surface 30a and the second sealing surface 30b form a right angle as shown in FIG. 12, and the first sealing surface 29a engages the valve body 15, and the second sealing surface 29b
engages with 27 protrusions 31 of the second ring groove. The pressure receiving part 30e extends from the sealing part 30 by the same height as the height of the projection part 31.
It is formed to be higher than C. An end surface 30f of the pressure receiving portion 30e is inclined diagonally downward to the left. Therefore, when the exhaust gas pressure Fa acts perpendicularly to the end surface 30f, a force Fil that urges the second ring 30 leftward and a force Fv that urges the second ring 30 upward act.

The second ring 30 is also inserted into the second ring groove 27 in the same manner as the first ring 29.

In FIG. 1, the smaller the valve opening angle α, the larger the valve opening becomes, and when α=0, the valve becomes fully open. On the other hand, α increases and α=
When it reaches 90 degrees, it is fully open. At this time, as shown in FIGS. 9 and 12, the first seal surfaces 29a and 30a of the first ring 29 and the second ring 30 are in close contact with the peripheral edge of each side surface of the valve body 15, respectively, and each ring 29.3
0 is the force F based on the exhaust gas pressure Fc, which causes the valve body 1 to
5, respectively. Further, each second sealing surface 29b and 30 of the first ring 29 and the second ring 30
b are in close contact with the projections 28°31, respectively, and each ring 29.3
0 are respectively urged toward the projections 28 and 31 by a force F based on the exhaust gas pressure Fc. Therefore, the space between the valve body 15 and the first and second valve seats 24.25 is closed by the first and second rings 29.30. Therefore, the valve body 15, the valve seat 24, 25, and the valve stem 16
valve body 1 without increasing the machining accuracy and assembly accuracy.
5 and the valve seats 24, 25 can be improved.

Furthermore, in this embodiment, since the valve opening angle α is 90 degrees when the exhaust control valve is fully open, the shapes of the valve body 15, valve seat 24, 25, ring grooves 26, 27, and rings 29, 30 are circular. , which makes machining easier.

Also, when attaching the rings 29 and 30 to the valve body, compared to when attaching them to the valve body 15 as described later,
When the opening degree of the valve body is small, even if the rings 29.30 vibrate due to turbulence in the gas flow, the rings 29.
Since the force due to the vibration of 30 is not applied, the flow rate can be accurately controlled.

Furthermore, since the valve body has a large heat radiation area, deformation of the ring grooves 26 and 27 over time due to heat can be reduced.

Next, the second valve opening angle α is smaller than 90 degrees when fully closed.
An example will be described. Referring to FIG. 14, when the valve opening angle α is 75 degrees, the valve is fully open. Accordingly, the first valve seat 24 and the second valve seat 25 are inclined, and the respective first seal surfaces 2 of the first ring 29 and the second ring 30 are inclined.
9a and 30a are also inclined. Moreover, the shape of the valve body 15,
The shapes of the first and second ring grooves 2627 and the shapes of the first and second rings 29.30 are determined by the valve opening angle α when fully closed.
It has a circular shape depending on the .

According to this embodiment, since the operating angle of the exhaust control valve from fully open to fully closed, that is, the valve opening angle α, can be reduced, the stroke of the actuator for operating the exhaust control valve can be reduced. . Therefore, the actuator can be downsized.

Further, since the turbulence of the exhaust gas flow when the valve body 15 is slightly opened is reduced, flow rate control can be facilitated.

Next, a third embodiment will be described with reference to FIGS. 15 to 17. This embodiment is almost the same as the first embodiment, except that a first ring groove and a second ring groove are provided in the valve body. Therefore, this different point will be explained.

Referring to FIG. 15, a first ring groove 40 is formed at the peripheral edge of the left side surface 15a of the valve body 15. As shown in FIG. As shown in FIGS. 16 and 17, the first ring groove 40 is formed in an annular shape extending approximately half a circumference up to the position where the valve shaft 16 is attached, and the first ring 29 is provided in the first ring groove 40. is inserted. As shown in 15iEI, when the valve body 15 is in the fully closed position, the first ring 29 is pressed by the pressure of the exhaust gas, so that the first sealing surface 29a of the first ring 29 is brought into close contact with the first valve seat 24. The second sealing surface is brought into close contact with the protrusion 28 of the first ring groove 40. Valve body work 5
A second ring groove 41 is formed at the peripheral edge of the right side surface 15b. As shown in FIG. 16, the second ring groove 41 is formed in an annular shape extending approximately half a circumference to the position where the valve shaft 16 is attached, and the second ring 30 is inserted into the second ring groove 41. As shown in FIG. 15, when the valve body 15 is in the fully closed position, the second ring 30 is pressed by the pressure of the exhaust gas, so that the first sealing surface 30a of the second ring 30 is pressed against the second valve seat 25. The second sealing surface is brought into close contact with the protrusion 31 of the second ring groove 41.

As described above, according to this embodiment, the same effects as the first embodiment can be obtained. Moreover, since the first and second ring grooves 40.41 are formed in the valve body 15,
Since both ends of the first ring groove 40 and both ends of the second ring groove 41 can be machined to a position close to the center of the valve shaft 16, both ends of the first ring 29 and both ends of the second ring 3
By bringing both ends of the valve 0 into contact with the valve shaft 16, the sealing performance between the valve body and the valve seats 24 and 25 can be further improved. Further, when forming the ring grooves 40, 41 in the valve body 15, processing is easier than when forming the ring grooves 26, 27 in the valve body 20 as in the first embodiment.

In addition, in this embodiment as well, similarly to the second embodiment, the valve opening angle α when the valves are all open may be smaller than 90 degrees.

A fourth embodiment is shown in FIGS. 18 and 19.

The fourth embodiment is almost similar to the third embodiment, but the first embodiment is similar to the third embodiment.
Since the shapes of the ring groove and the second ring groove are different, this difference will be explained. FIG. 20 shows an enlarged view of the valve body 15, and FIG. 21 shows a sectional view taken along line XXI-XXI in FIG. 20. Referring to FIGS. 20 and 21, the valve stem of the valve body 15 is attached to the notch 4 at the position.
5 is formed. Both ends of the first ring groove 40 have cutout portions 4.
It opens at 5. The protrusion 28 of the first ring groove 40 extends to both ends of the first ring groove 40 . The width W of the first ring groove 40 is slightly larger than the width W of the first ring 29,
The width Wp of the protrusion 28 is approximately 1/2 of the width WR of the first ring.
That's about it. Therefore, the first ring 29 is connected to the first ring groove 4.
Hard to fall off from 0.

When inserting the first ring 29 into the first ring groove 40, from the opening of the first ring groove 40 to the notch 45,
The tip of the ring 29 is inserted into the first ring groove 40.

The second ring groove 41 shown in FIGS. 18 and 19 is also formed in the same manner as the first ring groove 40, and the second ring 30 is also inserted into the second ring groove 41 in the same manner as the first ring 29. Ru.

22 and 23 show a valve shaft 47 attached to the notch 45 of the valve body 15. As shown in FIG. One end 47a of the valve shaft 47
has a shape corresponding to the notch 45, and this one end 47a
A recess 47 having a width equal to the plate thickness of the valve body 15 is provided at the tip of the valve body 15.
b is formed. One end 47a of the valve shaft 47 is fitted into the notch 45 of the valve body 15, and at this time, the valve shaft 47-end 47
The valve body 15 is fitted into the recess 47b of a.

As a result, the opening of the ring groove 40.41 to the notch is closed, thereby preventing the first and second rings 29.30 from falling off from the first and second ring grooves 40.41, respectively. can.

〔Effect of the invention〕

Since the sealing member is biased to close the space between the valve seat and the valve body, it is possible to improve the sealing performance between the valve seat and the valve body when the exhaust passage is fully closed.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the first embodiment of the exhaust control valve, Figure 2 is a right side view of the valve body in Figure 1, Figure 3 is a front view of the valve stem in Figure 1, and Figure 4. is the right side view of the valve stem in Figure 3, and Figure 5.
The figure is a right side view of the exhaust control valve in Figure 1, Figure 6 is an enlarged view of the first valve seat in Figure 2, Figure 7 is a front view of the first ring, and Figure 6 is an enlarged view of the first valve seat in Figure 2.
The figure is a plan view of the first ring in Fig. 7, and Fig. 9 is a plan view of the first ring in Fig. 7.
Figure 11 is a bottom view of the second ring in Figure 10. Figure 12 is along the xn-xn line in Figure 10. View along the line, 1st
Fig. 3 is an overall schematic diagram of a two-stage turbo internal combustion engine equipped with an exhaust control valve, Fig. 14 is a vertical sectional view of a second embodiment of the exhaust control valve, and Fig. 15 is a third embodiment of the exhaust control valve. An example vertical sectional view, FIG. 16 is a right side view of the exhaust control valve in FIG. 15, and FIG.
The figure is an enlarged left side view of a part of the valve body in FIG. 15, FIG.
Figure 8 is a right side view of the exhaust control valve, Figure 20 is an enlarged left side view of a portion of the valve body in Figure 18, and Figure 21 is XXI in Figure 20.
22 is a front view of the valve shaft in FIG. 19, and FIG. 23 is a right side view of the valve shaft in FIG. 22. 9... Exhaust control valve, 15... Valve body, 16.47
...Valve stem, 21...Valve passage, 24...First
Valve seat, 25...Second valve seat, 29...First ring, 30...Second ring. Exhaust Control Valve Valve Body Valve Stem Valve Passage First Valve Seat Second Valve Seat First Ring Second Ring 5 Fig. 12 Fig. 1 Fig. 4 Fig. 15 Fig. 16 Fig. - /9 7 Valve Stem No. 8 Figure 19

Claims (1)

[Claims] A valve body rotatable around the valve shaft is disposed in the exhaust passage, a first valve seat on which one side of the valve body can be seated, and a second valve seat on which the other side of the valve body can be seated. an exhaust control valve for an internal combustion engine, wherein the exhaust control valve for an internal combustion engine is provided with a valve seat, and the exhaust passage is completely closed by the valve body being seated on the first valve seat and the second valve seat. seat and said second
A seal member is disposed between at least one of the valve seats and the valve body, and the seal member is arranged between at least one of the first valve seat and the second valve seat when the exhaust passage is fully closed. An exhaust control valve for an internal combustion engine, the exhaust control valve for an internal combustion engine being biased by exhaust gas pressure to close between one end and the valve body.