JPH0350268Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention forms a plurality of exhaust gas passages in the turbine casing of an exhaust turbo supercharger, and connects the plurality of exhaust gas passages with appropriate valve devices. The present invention relates to an exhaust turbocharging device in which the passage area of the exhaust gas passage in the turbine casing is variable by controlling opening and closing according to the operating state of the engine.

(Prior Art) In a conventional exhaust turbo supercharger, a single exhaust gas passage is formed inside the turbine casing, and the passage area of the exhaust gas passage is fixedly set, and the area of the exhaust gas passage is fixedly set. A/
It was customary to set the R value (A: passage area of the exhaust gas passage of the turbine casing, R: radius of curvature of the scroll portion of the turbine casing) according to the amount of exhaust gas during medium-speed operation of the engine. .

However, if the A/R value is set in accordance with the medium-speed operation of the engine, the amount of exhaust gas will be higher than the above-mentioned standard exhaust gas amount in the high-speed operation region of the engine. Problems include increased gas flow resistance, the exhaust energy of the exhaust gas cannot be fully utilized, and the exhaust pressure increases on the engine side, resulting in poor combustibility and insufficient engine output. On the other hand, in the low speed operating range of the engine, the flow rate of exhaust gas decreases as the amount of exhaust gas becomes less than the above standard exhaust gas amount, and the turbine wheel cannot rotate sufficiently, resulting in a decrease in turbine efficiency. This results in a problem that the amount of energy decreases.

In order to improve the disadvantages peculiar to an exhaust turbo supercharger equipped with a turbine casing having a single exhaust gas passage, the exhaust gas passage in the turbine casing is divided into a plurality of sections by partition walls, and the exhaust gas passage is divided into a plurality of sections by partition walls. By controlling the opening and closing of the exhaust gas passage using a valve device, the passage area of the exhaust gas passage can be varied depending on the engine operating condition, thereby ensuring a high level of supercharging performance throughout the entire engine operating range. Attempts are being made to develop this technology (see, for example, Japanese Patent Laid-Open No. 18522/1983).

However, in the case of such a configuration, the exhaust gas passage in the turbine casing has a partition between the inner peripheral side (point A side) and the outer peripheral side (point B side) of the passage 6, as shown in FIG. 26 are different in temperature (Ta>Tb), cracks (indicated by virtual line C) occur irregularly over the entire length of the partition wall 26 due to thermal stress caused by the temperature difference, and in the worst case, The partition wall 26 may partially fall off, or the partition wall 26 may be deformed on the inner circumferential side due to being restrained by the highly rigid outer wall 21 of the turbine casing, causing interference with the turbine blade (as shown by the imaginary line D). There is.

In order to solve this problem, for example, as shown in Japanese Utility Model Application Publication No. 52-133809, a dividing line (imaginary line (denoted by S)
However, such a configuration cannot provide a countermeasure against cracks over the entire length of the partition wall 26, and even if it is formed over the entire length (which is difficult in reality), it would be difficult to prevent the temperature difference in the radial direction of the partition wall 26. Therefore, it cannot work effectively as a countermeasure against the above-mentioned cracks that occur. (In other words, such a dividing line S
(There is almost no stress reduction effect on the deformation force of the partition wall as shown by the imaginary line D).

In addition, when the dividing line S is formed in the partition wall 26 in this way, adjacent exhaust gas passages communicate with each other via the dividing line S, and one exhaust gas passage is connected to the other exhaust gas passage (low-speed operation time currently closed)
This has the disadvantage that exhaust gas leaks into the engine, resulting in a reduction in turbine efficiency (especially when the engine is running at low speeds).

(Purpose of the invention) The present invention has been made to improve the above-mentioned drawbacks, and includes partitioning the exhaust gas introduction passage in the turbine casing into a plurality of exhaust gas passages by partition walls along the flow direction of the exhaust gas. In an exhaust turbocharging device that allows exhaust gas to flow through all or part of the exhaust gas passage depending on the operating state of the engine, it is possible to prevent unexpected cracks from occurring in the partition wall in the turbine casing due to temperature differences. The purpose of this is to prevent such problems from occurring and also to prevent a decrease in turbine efficiency from occurring.

(Means for achieving the object) In order to achieve the above object, the present invention divides the exhaust gas introduction passage in the turbine casing into a plurality of exhaust gas passages by partition walls along the flow direction of the exhaust gas, In an exhaust turbo supercharging device that allows exhaust gas to flow through all or part of the exhaust gas passages depending on the operating state of the engine, one of the two wall surfaces of the partition wall is used only in the high-speed operating range of the engine. A thin wall portion extending in the radial direction of the turbine casing is formed only on the wall surface on the exhaust gas passage side.

(Function) According to the above means, even if excessive thermal stress is generated in the partition wall portion, the thermal stress is concentrated on the thin wall portion formed in advance, and cracks are generated in the thin wall portion at an early stage. Therefore, it is possible to avoid the conventional situation in which cracks occur irregularly in the partition wall, or in which damage spreads to the outer wall of the turbine casing due to such irregular cracks.

Moreover, since the thin wall portion is formed only on the wall surface on the exhaust gas passage side, which is used only in the high-speed operating range of the engine, the uneven surface formed by the thin wall portion is The exhaust gas flowing through the exhaust gas passage during low-speed operation, which is used during the entire operating time of the engine, acts only as a flow resistance to the exhaust gas flow only during high-speed operation, which does not account for a large proportion of the engine's total operating time. Regarding gas, the thin wall portion does not pose an obstacle as a flow resistance. Therefore, a decrease in turbine efficiency due to the formation of the thin wall portion as described above is suppressed to a minimum. It goes without saying that in the present invention, there is no leakage of the exhaust gas flow across the two mutually adjacent exhaust gas passages, which occurs when the dividing line S in FIG. 11 is formed.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 10.

First, FIGS. 1 to 6 show an exhaust turbo supercharging device according to an embodiment of the present invention. In FIG. 4, reference numeral 1 is an engine body, 2 is an exhaust turbo supercharger, The exhaust turbo supercharger 2 is fixed to an exhaust pipe 4 via a gasket 3 (see FIG. 6).

As shown in FIGS. 3 and 4, the exhaust turbo supercharger 2 includes a turbine casing 21 containing a turbine wheel 50, and a compressor casing 22 containing a compressor wheel (not shown).
are connected to each other via a center casing 23.

As shown in FIGS. 3, 4, and 6 to 8, the turbine casing 21 has a scroll-shaped exhaust gas passage formed therein by a partition wall 26 extending in the scroll direction. Two exhaust gas passages lined up in the axial direction of the turbine casing 21, that is, a first exhaust gas passage 27 with a substantially oval cross section located on one side of the partition wall 26;
The second exhaust gas passage 28 is located on the other side of the exhaust gas passage 6 and has a generally oval cross section and has a smaller passage area than the first exhaust gas passage 27. And the above two exhaust gas passages 2
Reference numerals 7 and 28 refer to exhaust gas inlet ports 29 and 30, both of which are configured as open ends on the upstream side of the exhaust gas, to an end surface 21a on the upstream side of the exhaust gas of the turbine casing 21, which acts as an abutment surface to the exhaust pipe 4 side. It is open at the top. Furthermore, these two exhaust gas inlets 2
Of the 9 and 30, the first exhaust gas inlet 29 is always open throughout the entire operating range of the engine, but the second exhaust gas inlet 30 is controlled by a valve device 6, which will be described later. It is closed when the engine is operating at low speed with little exhaust gas flow, and is opened when the engine is operating at high speed with a large flow rate of exhaust gas. Therefore, when the engine is operating at low speed, only the first exhaust gas inlet 29 is opened, and the exhaust gas flows through the first exhaust gas passage 27.
The exhaust gas is introduced into the scroll part 21b side of the turbine casing 21 through the engine, and when the engine is running at high speed, both the first exhaust gas inlet 29 and the second exhaust gas inlet 30 are open, and the exhaust gas is introduced into the scroll part 21b side of the turbine casing 21. Gas is introduced into the scroll portion 21b side of the turbine casing 21 from both the first exhaust gas passage 27 and the second exhaust gas passage 28.

The first of both wall surfaces of the partition wall 26 is
On the wall surface on the exhaust gas passage 27 side, for example, as shown in FIGS. 1 to 3, there are a plurality of holes having a predetermined width extending in the radial direction of the winding circle of the turbine casing 21 at predetermined intervals in the scroll direction. Thin wall portion 26a
~26c is formed.

If the thin-walled portions 26a to 26c are formed at predetermined intervals and extend in the radial direction as described above, even if the thermal stress described in the prior art section occurs under the flow of the exhaust gas, the Cracks caused by thermal stress initially occur as hair cracks only in the thin wall portions 26a to 26c, and thereafter these thin wall portions 26a to 26c function in the same way as if they had formed slits to absorb the restraint of the partition wall 26. It acts to relax and also prevent deformation of the turbine casing 21 itself. Therefore, partition wall 2
6 will not fall off due to cracks, and the partition wall itself will not be deformed.

Furthermore, at least the exhaust gas passages 27 and 2 of the partition wall 26 in the turbine casing 21
At the beginning of winding No. 8, there is a tongue portion 2 as shown in Fig. 1.
9 is formed, and one 26a of the thin-walled portions 26a to 26c extending in the radial direction of the turbine is located near the tongue portion 29.

Therefore, when the exhaust turbo supercharger is in operation,
Even if a large temperature difference occurs before and after the tongue portion 29 in the scrolling direction, resulting in excessive thermal stress, the strength of the thin wall portion 26a is the lowest, so the thermal stress acts on the tongue portion 29 portion. is absorbed and relaxed in the thin wall portion 26a, and as a result, even if a crack occurs in the thin wall portion 26a, the crack will be absorbed by the thin wall portion 26a.
Cracks that are limited to the outer wall of the turbine casing 21 and extend to the outer wall of the turbine casing 21 will not occur.

Further, in this embodiment, the second exhaust gas inlet 30 including the end surface 260 of the partition wall 26 among the end surfaces 21a of the turbine casing 21
A substantially elongated annular portion located at the edge of the valve serves as a valve seat surface 33 for a valve device 6, which will be described later.

In this way, the end face 2 of the turbine casing 21
If part of 1a is used as the valve seat surface 33 of the valve device 6, the second exhaust gas inlet 30 will open facing the exhaust gas flow direction. Therefore, when the valve device 6 is in the open state, the exhaust gas flows smoothly into the turbine casing 21 almost linearly with low flow resistance. In addition, in this case, the entire area of the opening of the second exhaust gas inlet 30 can effectively function as a flow path for exhaust gas, and therefore, for example, when the flow rate of exhaust gas is constant, When the flow rate of the second exhaust gas inlet 30 is constant, the second exhaust gas inlet 30 This is advantageous in terms of making the device more compact, as the diameter of the valve can be made smaller and the valve device 6 can also be made smaller accordingly.

Furthermore, since the planar direction of the valve device 33 is substantially perpendicular to the exhaust gas flow direction, compared to the case where the planar direction of the valve seat surface 33 and the exhaust gas flow direction are substantially parallel. Therefore, the sealing performance on the valve seat surface 33 is good (that is, the valve device 6 described later
When the valve body 61 is seated on the valve seat surface 33, the extending direction of the sealing surface between them is perpendicular to the flow direction of the exhaust gas, and the flow resistance of the exhaust gas leaking along the sealing surface increases accordingly. Therefore, the exhaust gas flow control will be performed more reliably.

In FIG. 4, reference numeral 31 is a waste gate valve having a known structure provided on the side of the turbine casing 21, and the waste gate valve 31 is activated in response to intake pressure (supercharging pressure) of the engine. The opening/closing is controlled by the first actuator 8.

The exhaust pipe 4 is connected to an exhaust port of each cylinder of the engine body 1 (not shown) as shown in FIGS. 4 to 6.
A branch pipe section 41 consisting of four branch pipes 41A, 41B, etc. connected in a substantially horizontal direction to the
and the branch pipe portion 4 while converging the branch pipes 41A, 41B, etc. at the downstream end of the exhaust gas.
1 and a collecting pipe part 42 extending in a direction perpendicular to the branch pipe part 41, the end surface 4a on the side of the branch pipe is connected to the engine main body 1.
It is fastened and fixed to the side of the engine body 1 in a state where the sides abut, and the end surface 4b on the collecting pipe section 42 side (i.e., the upper end surface 42a of the collecting pipe section 42) includes:
As shown in FIGS. 6 and 7, a turbine casing 21 of the exhaust turbo supercharger 2 is abutted and fixed via a gasket 3. As shown in FIGS.

A continuous portion 46 located at the exhaust gas upstream end of the collecting pipe portion 42 of the exhaust pipe 4 and continuing to the branch pipe 41 is indicated by a projected line l ₁ in FIG. 7 and an imaginary line l ₂ in FIG. As shown, when the turbine casing 21 is fastened and fixed to the end surface 4b of the exhaust pipe 4, the first exhaust gas inlet 29 of the turbine casing 21 in the vertical direction (that is, in the exhaust gas flow direction) and second
The opening has a substantially square cross section and has an opening area and an opening direction such that the exhaust gas introduction ports 30 of the exhaust gas introduction ports 29 and 30 can be viewed simultaneously and in a direction along the opening direction of each of the exhaust gas introduction ports 29 and 30. Therefore, the exhaust gas collecting passage 43 in the collecting pipe portion 42 and the exhaust gas passage on the turbine casing 21 side, which is formed by the first exhaust gas passage 27 and the second exhaust gas passage 28, are continuous approximately coaxially. Therefore, the exhaust gas G flowing through the exhaust pipe 4 from the branch pipe section 41 side to the collecting pipe section 42 is guided to the continuous section 46 and flows into the collecting pipe section 42, as shown in FIG. flows linearly along its axial direction, and is smoothly introduced into the first exhaust gas inlet 29 and second exhaust gas inlet 30 side of the turbine casing 21 with almost no flow resistance. It turns out.

Further, this exhaust pipe 4 has a side wall 4 of the side wall of the collecting pipe portion 42 on the side facing the second exhaust gas inlet 30 of the turbine casing 21.
8 is bulged outward by an appropriate amount from the continuous portion 46 at a position closer to the end surface 4b, and is located inside thereof in a continuous manner with the exhaust gas collecting passage 43 and on the side thereof, and has one end thereof An expansion part 4 having an appropriately sized expansion space 4 that opens on the end surface 4b.
It is set at 4. This expanded portion 44 functions as an attachment and storage space for a valve device 6, which will be described later.

The valve device 6 is attached to the expanded portion 44 of the exhaust pipe 4 as shown in FIGS. 7 to 10, and is connected to the second exhaust gas inlet 3 of the turbine casing 21.
In particular, in this embodiment, the valve device 6 is a swinging type valve device as will be described later. That is, as shown in FIG.
Of the pair of side walls facing each other in the longitudinal direction of
A valve support body 62 whose operating center shaft 65 is rotatably supported by a bearing cylinder 66 provided through the shaft (in a direction parallel to the long axis direction of the valve support body 62); The valve body 61 is supported so as to be able to float with respect to a formed valve holding plate 63 via a pair of connecting pins 67 and 68. This valve body 61 is connected to the second exhaust gas inlet 30 of the end face 21a of the turbine casing 21, as shown in FIG.
of the turbine casing 21, which closes at least the second exhaust gas inlet 30 and covers the end surface 26a of the partition wall 26 of the turbine casing 21. The valve body 6 is formed into an oval plate having a size that allows the valve body to open.
A ventilation hole 7 of an appropriate diameter that penetrates 1 in the thickness direction.
1 is formed.

In this way, when the end face 26a of the partition wall 26 is covered by the valve body 61 when the valve device 6 is in the closed state, thermal oxidation or cracking of the partition wall 26 may occur as described later. The thermal deterioration phenomenon is suppressed as much as possible, and the flow resistance of exhaust gas is also reduced. That is, when the valve device 6 is in the closed state, the end surface 2 of the partition wall 26 is closed by the valve body 61.
When the end face 26a is covered, the frequency at which the end face 26a is directly exposed to high-temperature exhaust gas is reduced compared to a structure in which the end face 26a is directly exposed to exhaust gas throughout the entire operating range of the engine. (Note that the rate at which the valve device 6 is closed throughout the entire operating range of the engine is normally approximately 70 to 80%.
%), thermal oxidation near the end face of the partition wall 26 is prevented as much as possible. Also,
Since the temperature rise of the partition wall 26 is suppressed,
The occurrence of cracks due to thermal stress near the end face of the partition wall 26 is prevented, and the durability of the turbine casing 21 is thereby improved. Furthermore, since thermal oxidation and crack generation near the end faces of the partition walls 26 are prevented as described above, it is possible to reduce the overall thickness of the partition walls 26. Therefore, the turbine casing 21 is made lighter and more compact, and the partition wall 26 is
The flow resistance of the exhaust gas when the valve device 6 is in the open state is reduced by the amount that the valve device 6 is thinned, which is advantageous for improving supercharging performance.

On the other hand, the pair of connecting pins 67 and 68 connecting the valve body 61 and the valve holding plate 63 of the valve support body 62 are connected to the valve body 61 as shown in FIGS. 9 and 10. A pin receiving hole 7 is formed in the valve holding plate 63 of the valve support 62, and has fitting shaft portions 67a and 68a that are fixed to the valve holding plate 63 of the valve support 62, respectively, and are fixed at appropriate intervals in the longitudinal direction of the valve support 62.
2, 72 so as to be freely movable. The above-mentioned fitting shaft portion 67a of this pair of connecting pins 67, 68,
The length of the valve body 68a is set to be longer than the thickness of the valve retainer plate 63 by an appropriate length so that the valve body 61 and the valve retainer plate 63 can be supported so as to be able to float relative to each other. For this reason, the valve device 6
When opening the valve from the closed state (the state shown in FIG. 9), the valve body 61 and the valve retaining plate 63 are moved as shown in FIG. 10 at the beginning of the valve opening operation.
In between, there is a parallel gap 7 communicating with the ventilation hole 71.
4 is formed, and the second exhaust gas passage 28 of the turbine casing 21 and the exhaust gas collecting passage 43 of the exhaust pipe 4 are brought into communication with each other via the vent hole 71 and the gap 74.

Therefore, when the valve device 6 is rotated from its closed state in the direction of arrow A (see FIG. 7) to open the valve as shown in FIG. 9, the static pressure of the exhaust gas is and dynamic pressure is applied to the upper surface 61a of the valve body 61.
Since the load is applied to the valve side, a large actuation force is required to open the valve body 61 against the pressure of the exhaust gas, but in this embodiment, the valve body 61 is Since the valve body 61 is supported in a floating manner on the support body 62 and has a vent hole 71 formed in the valve body 61, the valve body 61 and the valve retaining plate are connected at the initial stage of opening of the valve device 6, as shown in FIG. 63 is separated from the high pressure exhaust gas collection passage 43.
and a low pressure second exhaust gas passage 28 are in communication with each other. Therefore, part of the exhaust gas flows into the second exhaust gas passage 28 side through the vent hole 71, and the pressure difference between the two is reduced as much as possible (in other words, the opening to the valve body 61 is reduced). (The valve direction regulating force is reduced), and the valve device 6 can be opened smoothly and quickly with a smaller actuation force (that is, the valve actuation device 7, which will be described later, is miniaturized and the center of operation is (The wear resistance of the shaft 65 or bearing sleeve 66 is improved).

Further, in this case, each pin receiving hole 72, 72 of the valve holding plate 63 is connected to the connecting pin 67, 68, respectively.
Since the heads 67b and 68b of the exhaust gas collecting passage 43 are substantially closed, the second
Exhaust gas flowing out to the exhaust gas passage 28 side flows into the vent hole 71 side from the gap 74 between the valve body 61 and the valve holding plate 63 without passing through the pin receiving holes 72, 72. Become. For this reason, each pin receiving hole 72, 7 plays an important role in valve function.
This prevents the inner circumferential surface of the valve device 6 from being exposed to high temperature exhaust gas and thermally deteriorating, resulting in an excessive amount of free movement between the valve body 61 and the valve support body 62, which impairs the function of the valve device 6. Prevented.

In addition, since the valve body 61 and the valve holding plate 63 are connected to each other so as to be able to freely float, for example, if the gasket 3 interposed between the exhaust pipe 4 and the turbine casing 21 collapses due to aging, Even if the valve body 61 or the valve seat surface 33 is worn out due to long-term use, the valve body 61 will float and displace following the changing state of the relative relationship between the two, and the valve body 61 and the valve seat surface 33 will be The adhesion, that is, the sealing performance, is maintained well over a long period of time.

Furthermore, in this valve device 6, the valve body 61 and the valve holding plate 63 are integrated with connecting pins 67, 6.
8, the relative positioning of the valve body 61 and the valve holding plate 63 in the plane direction is easy, and the once set relative position does not shift during use (the valve body 61 Securing positioning function). Therefore, it is possible to make the valve body 61 oval rather than circular, and it is possible to make the valve body 61 more compact than when the valve body 61 is circular.
Further, the advantage that positioning of the valve body 61 is easy and that positional deviation does not occur is as follows.
As described above, the opening shape of the second exhaust gas inlet 30 is formed not in a circle but in an oval shape, that is, the relative distance between the second exhaust gas inlet 30 and the operation center axis 65 of the valve device 6 can be changed. This makes it possible to make the opening area of the second exhaust gas inlet 30 as large as possible while keeping the opening area of the second exhaust gas inlet 30 as small as possible. Compared to the case where the introduction port 30 is circular, the second
By shortening the distance between the exhaust gas inlet 30 and the operating center axis 65, that is, the arm length of the valve support 62 as much as possible, it is possible to reduce the valve opening operating force of the valve device 6. (That is, light and smooth operation of the valve device 6 is realized). That is, in this embodiment, the ability to shorten the arm length of the valve support body 62 in this way and the formation of the vent hole 71 in the valve body 61 as described above combine to reduce the opening of the valve device 6. The operating force is further reduced.

On the other hand, this valve device 6 has a valve operating device 7 which will be described later.
Accordingly, arrow A is centered on the operation center axis 65.
- The valve is rotated in the B direction, and the valve is in the closed position shown by a solid line in Fig. 7 and shown by a chain line (symbol 6')
In this case, in the open position of the valve device 6, the valve device 6 is housed in the expansion space 45 of the exhaust pipe 4. (In other words, it is located closer to the extended portion 44 than the projection line l ₁ of the continuous portion 46)
As such, the arm length of the valve support 62 or the mounting position of the operating center shaft 65 are set appropriately. By doing this, when the valve device 6 is in the open state, the exhaust gas collecting passage 43 of the exhaust pipe 4
A valve device 6 whose passage area is positioned at the valve open position.
The flow resistance of the exhaust gas is reduced as much as possible, and the valve support of the valve device 6 is not substantially reduced when the valve device 6 is in the closed state. body 62 and central axis of operation 65
(Substantially the bearing sleeve 66) prevents the exhaust gas from directly hitting the exposed portion facing the expansion space 45 of the end surface 21a of the turbine casing 21 as much as possible, and the end surface 21a thermal deterioration is suppressed. From this, the durability of the turbine casing 21 is improved.

Further, since the valve device 6 is provided on the exhaust pipe 4 side, where the partition wall 26 is not formed and the structure is relatively simple, and therefore there is less irregular thermal deformation, the structure is relatively complex and the structure is relatively simple, and therefore the valve device 6 has a relatively simple structure and is therefore less prone to irregular thermal deformation. Compared to the case where the valve device 6 is provided on the turbine casing 21 side where thermal deformation is likely to occur, the effect of thermal deformation on the operating characteristics of the valve device 6 is smaller, and the operating accuracy of the valve device 6 is maintained at a higher level. It becomes possible to do so.

The valve actuating device 7 opens and closes the valve device 6 according to the operating state of the engine, and moves its actuator 10 forward and backward in response to air pressure that is appropriately controlled to be supplied depending on the operating state of the engine. It is composed of a second actuator 9 having a diaphragm-type pressure responsive mechanism configured to cause displacement, and as shown in FIGS. Installed insulated. That is, the collecting pipe portion 42 of the exhaust pipe 4
, an exhaust pipe insulator 12 made of a plate bent into a substantially U-shape is attached to the collecting pipe section 42.
The collecting pipe portion 4 is arranged so as to surround the outside of the other three side surfaces excluding the side surface facing the engine main body 1 side.
an insulator mounting part 42b that is fitted from the outside of 2 and formed in a bulge on one side of the collecting pipe part 42; and one side 12a of the actuator insulator 11 that faces the insulator mounting part 42b.
It is fixed by fastening them with a pair of mounting bolts 15, 15. Further, when the exhaust pipe insulator 12 is installed, the flat plate-shaped bracket 13 together with the exhaust pipe insulator 12 has its tip 13a projected outward from the outer end of the exhaust pipe insulator 12 that is closer to the engine body 1. With the above mounting bolt 1
5 and 15 are fastened together. Furthermore, the second actuator 9, whose outer periphery is enclosed by the actuator insulator 11 in the shape of a substantially airtight container, is attached to the tip 13a of the bracket 13 on the actuator 10 side of the actuator insulator 11. The one side surface 11a is sandwiched between the tip 13a of the bracket 13 and the front end surface 9a of the second actuator 9, and is fastened and fixed by a pair of mounting bolts 16, 16. Therefore, the second actuator 9 is fixed to the collecting pipe portion 42 of the exhaust pipe 4 via the two members, the actuator insulator 11 and the exhaust pipe insulator 12, in a substantially heat-insulating manner. The operating center shaft 65 of the valve device 6 is connected to the operating element 10 of the second actuator 9 mounted on the exhaust pipe 4 side through link levers 69 and 70. protrudes in the direction of arrow a (see Fig. 4), the valve device 6 rotates in the direction of arrow A (see Fig. 7), and the second exhaust gas inlet 30 is opened. When the actuator 10 moves backward in the direction of arrow b, the valve device 6 rotates in the direction of arrow B, and the second exhaust gas introduction port 30 is closed.

In this way, the exhaust pipe insulator 12 is attached to the outside of the exhaust pipe 4, and the actuator insulator 11 is attached to the tip 13a of the bracket 13, which is attached together with the exhaust pipe insulator 12 to the exhaust pipe 4 side. The encapsulated second actuator 9 is attached to its end surface 9a.
When the actuator insulator 11 is interposed between the bracket tip 13a and the insulators 11 and 12 are tightened together, the insulators 11, 12
This action prevents radiant heat from being transferred from the exhaust pipe 4 side to the second actuator 9 side as much as possible, and also prevents conductive heat transfer from the exhaust pipe 4 side via the bracket 13 to the actuator insulator 11. The amount of heat transferred to the second actuator 9 side is reduced as much as possible. Furthermore, when the entire circumference of the second actuator 9 is covered with the actuator insulator 11 as described above, the second actuator 9 is protected from collisions with flying stones, adhesion of sludge or rainwater, etc.
Actuator 9 can be protected. For these reasons, the durability of the second actuator 9 is improved.

Furthermore, since the temperature rise of the second actuator 9 is suppressed as much as possible as described above, the material of the diaphragm (not shown) of the second actuator 9 can be made of a low-grade material with relatively poor heat resistance. Therefore, the cost of the second actuator 9 can be reduced accordingly.

Further, the valve device 6 and a second valve device that operates the valve device 6 are provided.
Since both the actuator 9 and the actuator 9 are attached to the exhaust pipe 4 side, even if the exhaust pipe 4 is thermally deformed due to the influence of heat from exhaust gas, the second actuator 9 attached to the exhaust pipe 4 The relative relationship between the actuator 9 and the valve device 6 can be kept substantially constant, and the control accuracy of the valve device 6 can be maintained at a high level at all times. Furthermore, since both the valve device 6 and the second actuator 9 are attached to the exhaust pipe 4, the valve device 6 and the second actuator 9 are
This can be done while the actuator 9 is interlocked with each other, and its operation can be inspected with high precision in either the disassembled or assembled state of the device.
The assembly accuracy and ease of assembly between the second actuator 9 and the second actuator 9 are made good.

Next, the operation and effects of this exhaust turbocharging device will be explained.

When the engine is operated, exhaust gas G discharged from each cylinder on the engine main body 1 side is collected in the collecting pipe section 42 via each branch pipe 41A, 41B, etc. of the exhaust pipe 4, and then collected in the collecting pipe section 42. 42 exhaust gas collecting passage 43 into the exhaust gas passage in the turbine casing 21 of the exhaust turbo supercharger 2, that is, into the first exhaust gas passage 27 and the second exhaust gas passage 28, and the exhaust energy is introduced into the exhaust gas passage 27 and the second exhaust gas passage 28. The turbine wheel is driven, and the compressor wheel prepresses the intake air (intake supercharging). At this time, the valve device 6 is opened and closed depending on the operating state of the engine, and the introduction form of the exhaust gas is selected. That is, when the operating state of the engine is in a low-speed operating region where the flow rate of exhaust gas is low, the second actuator 9 sets the valve device 6 to the valve open position (FIG. 7, the position shown by the solid line), and conversely, the engine When the operating state of the valve device 6 is in a high-speed operating region where the flow rate of exhaust gas is high, the second actuator 9 operates the valve device 6.
is set to the valve open position (FIG. 7, the position shown by the chain line). Therefore, in the low-speed operating range of the engine where the amount of exhaust gas discharged is small, the exhaust gas flows only from the first exhaust gas passage 27 to the turbine casing 21.
Moreover, since the first exhaust gas passage 27 does not have an uneven surface due to the thin-walled parts 26a to 26c, its flow resistance is small, and even though the amount of exhaust gas is small, the exhaust gas is Sufficient gas flow velocity within the turbine casing 21 is ensured, and the rotation of the turbine wheel is maintained on the high rotation side, making it possible to obtain the supercharging effect by the exhaust turbo supercharger 2 from a lower speed range, resulting in supercharging at low speeds. It has good performance. Furthermore, in this case, the passage area of the exhaust gas passage is smaller than that in the case where both the first exhaust gas passage 27 and the second exhaust gas passage 28 are effective, so that the exhaust gas inlet side of the turbine casing 21 is The difference between the exhaust gas pressure at the exit of the scroll section and the exhaust gas pressure at the exit of the scroll section can be made larger (that is, the expansion ratio of the exhaust gas increases),
This results in a higher level of supercharging performance.

On the other hand, in the high-speed operating range of the engine where a large amount of exhaust gas is emitted, both the first exhaust gas passage 27 and the second exhaust gas passage 28 are opened, so a large amount of exhaust gas is simultaneously transmitted to the turbine from both of them. It can be smoothly introduced into the casing 21 without causing large flow resistance. Therefore, the exhaust energy of a large amount of exhaust gas is effectively used as driving force for the turbine wheel, improving supercharging performance, and since the exhaust pressure on the engine side is reduced, its combustibility is improved, This will result in higher engine output.

Moreover, in this case, among both wall surfaces of the partition wall 26, the wall surface on the second exhaust gas passage 28 side is formed with thin wall portions 26a to 26c for absorbing thermal stress. Even if a crack occurs due to the partition wall 26, the crack will be caused by the thin wall portion 2.
6a to 26c, and neither irregular cracks nor deformation of the partition wall 26 or the turbine casing 21 due to thermal stress occur.

In this case, the thin wall portions 26a to 26c form a somewhat uneven surface on the second exhaust gas passage 28 side, causing a flow resistance, but if the second exhaust gas passage 28 is open, The high-speed operating state of the engine is not a large proportion of the total operating time of the engine, and when viewed as a whole, the reduction in efficiency of the exhaust turbo supercharger due to the formation of the thin wall portions 26a to 26c is negligible. I can say that.

(Effects of the invention) As explained above, the present invention divides the exhaust gas introduction passage in the turbine casing into a plurality of exhaust gas passages by partition walls along the flow direction of the exhaust gas, and In an exhaust turbo supercharging device that allows exhaust gas to flow through all or part of those exhaust gas passages, of both wall surfaces of the partition wall, the exhaust gas passage side that is used only in the high-speed operation range of the engine is used. This is characterized in that a thin wall portion extending in the radial direction of the turbine casing is formed only on the wall surface.

Therefore, according to the present invention, even if excessive thermal stress is generated in the partition wall portion, the thermal stress will be concentrated in the thin wall portion formed in advance, causing cracks to occur in the thin wall portion at an early stage. Therefore, it is possible to avoid the situation where irregular cracks occur in the partition wall as in the conventional case, or where damage spreads to the outer wall of the turbine casing due to such irregular cracks.

Moreover, since the thin wall portion is formed only on the wall surface on the exhaust gas passage side, which is used only in the high-speed operating range of the engine, the uneven surface formed by the thin wall portion is The exhaust gas flowing through the exhaust gas passage during low-speed operation, which is used during the entire operating time of the engine, acts only as a flow resistance to the exhaust gas flow only during high-speed operation, which does not account for a large proportion of the engine's total operating time. Regarding gas, the thin wall portion does not pose an obstacle as a flow resistance. Therefore, a decrease in turbine efficiency due to the formation of the thin wall portion as described above is suppressed to a minimum. In addition, in the present invention, since a thin wall portion is simply formed in the partition wall, the exhaust gas flow that straddles the two mutually adjacent exhaust gas passages as seen when forming the dividing line S in FIG. Needless to say, no leakage occurs at all.

[Brief explanation of the drawing]

FIG. 1 is a central vertical cross-sectional view of a turbine casing of an exhaust turbocharger according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view taken along line A-A in FIG. 1, and FIG. 4 is a front view of the exhaust turbo supercharging device, and FIG. 5 is a sectional view taken along the line B-B in the figure.
The arrow view, Figure 6 is the - arrow view of Figure 4, Figure 7
6 is a sectional view of FIG. 6, FIG. 8 is a sectional view of FIG. 7, FIG. 9 is a sectional view of FIG. 8, and FIG. 10 is a state change diagram of the valve device shown in FIG. 9. , FIG. 11 is a structural explanatory diagram of a turbine casing portion of a conventional exhaust turbocharger. 1...Engine body, 2...Turbo supercharger, 4
...Exhaust pipe, 6...Valve device, 7...Valve actuation device,
8, 9... Actuator, 11, 12... Insulator, 21... Turbine casing, 22
... Combret casing, 23 ... Center casing, 26 ... Partition wall, 26a to 26c ...
Thin wall portion, 27... First exhaust gas passage, 28...
Second exhaust gas passage.

Claims (1)

[Scope of utility model registration request] The exhaust gas introduction passage in the turbine casing is divided into a plurality of exhaust gas passages by partition walls along the flow direction of the exhaust gas, and the exhaust gas is distributed through all or part of these exhaust gas passages depending on the operating state of the engine. In the exhaust turbo supercharging device, a thin wall portion extending in the radial direction of the turbine casing is formed only on the wall surface on the exhaust gas passage side, which is used only in the high-speed operation region of the engine, among both wall surfaces of the partition wall. An exhaust turbo supercharging device characterized by: