JP2013019337A - Multistage supercharging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration in sealability of a valve body of an exhaust bypass valve device for opening and closing a bypass flow path bypassing a turbine of a supercharger in a multistage supercharging system.SOLUTION: The multistage supercharging system includes: a first supercharger to which an exhaust gas discharged from an internal combustion engine is supplied; a second supercharger arranged in the upstream side of the first supercharger in the flow of the exhaust gas; and an exhaust gas bypass valve device for opening and closing a bypass flow path for supplying the exhaust gas discharged from the internal combustion engine to the first supercharger while bypassing the turbine of the second supercharger. The exhaust bypass valve device includes a valve body 51a for opening and closing a bypass flow path opening and an alignment means 52d for aligning the valve body 51a when the valve body 51a closes the bypass flow path opening.

Description

  The present invention relates to a multistage supercharging system.

  Conventionally, a two-stage supercharging system (multistage supercharging system) including two (plural) superchargers has been proposed. Such a two-stage supercharging system includes two superchargers having different capacities, and changes the supply state of exhaust gas to the two superchargers according to the flow rate of exhaust gas supplied from the internal combustion engine. To generate compressed air efficiently.

More specifically, the two-stage supercharging system includes, for example, a low-pressure supercharger (first supercharger) to which exhaust gas discharged from an internal combustion engine is supplied, and an upstream side of the low-pressure supercharger. And a bypass passage for supplying exhaust gas discharged from the internal combustion engine to the low pressure turbocharger by bypassing the turbine impeller of the high pressure turbocharger And an exhaust bypass valve device that opens and closes.
As such an exhaust bypass valve device, for example, the exhaust bypass valve device disclosed in Patent Document 2 can be applied.

  When the bypass passage is closed by the exhaust bypass valve device, the exhaust gas is supplied to the high pressure supercharger, and when the bypass passage is opened by the exhaust bypass valve device, the exhaust gas is supplied to the low pressure stage supercharger. It is comprised so that it may be supplied to.

JP 2009-92026 A Japanese translation of PCT publication No. 2002-508473

Incidentally, the exhaust bypass valve device includes a valve body that directly opens and closes the bypass flow path, and opens and closes the bypass flow path by rotating the valve body.
When such opening and closing of the bypass channel is repeated for a long period of time, the valve body and the support body supporting the valve body are worn by rubbing. Then, the valve body and the support body are slightly displaced from the original positional relationship due to the gap due to such wear and the gap between the valve body and the support body that originally exist. As a result, the position of the valve body when closing the bypass channel is slightly shifted from the bypass channel opening.

  The power of the actuator that moves the valve body is accurately transmitted when the position of the valve body is arranged at a normal position (that is, the center of the operating force) with respect to the bypass flow path opening. For this reason, if the position of the valve body is slightly shifted with respect to the bypass flow path opening, the power of the actuator is not accurately transmitted to the valve body, the sealing performance of the valve body deteriorates, and the original two-stage turbocharging system The performance cannot be demonstrated.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent deterioration of the sealing performance of a valve body in a multistage supercharging system.

  The present invention adopts the following configuration as means for solving the above-described problems.

  According to a first aspect of the present invention, a first supercharger to which exhaust gas discharged from an internal combustion engine is supplied, and a second supercharger disposed upstream of the exhaust gas flow from the first supercharger. And an exhaust bypass valve device that opens and closes a bypass passage that bypasses the turbine impeller of the second supercharger and supplies the exhaust gas discharged from the internal combustion engine to the first supercharger. A supercharging system, wherein the exhaust bypass valve device aligns the valve body when the valve body closes the bypass passage opening, and a valve body that opens and closes the bypass passage opening. The configuration of providing means is employed.

  According to a second invention, in the first invention, the exhaust bypass valve device includes an attachment portion to which the valve body is attached, and an actuator that opens and closes the valve body by rotating the attachment portion. A configuration is adopted in which the aligning means is a guide surface that is provided on the surface of the mounting portion and that contacts the valve body to guide the valve body.

  A third invention adopts a configuration in which, in the second invention, the guide surface is a curved surface.

According to the present invention, the valve body is aligned by the aligning means when the valve body closes the bypass flow path opening.
For this reason, according to this invention, when closing a bypass flow-path opening, a valve body can always be correctly arrange | positioned in a normal position with respect to a bypass flow-path opening.
Therefore, according to this invention, the position of a valve body can be arrange | positioned according to the operating force center of an actuator, and it can prevent that the sealing performance of a valve body deteriorates.

It is a mimetic diagram showing a schematic structure of an engine system provided with a multistage supercharging system in one embodiment of the present invention. It is an enlarged view containing the exhaust bypass valve apparatus with which the multistage supercharging system in one Embodiment of this invention is provided. It is an enlarged view including the valve body and attachment plate of an exhaust bypass valve device with which the modification of the multistage supercharging system in one embodiment of the present invention is provided.

  Hereinafter, an embodiment of a multistage turbocharging system according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size. In the following description, a two-stage supercharging system including two superchargers will be described as an example of a multistage supercharging system.

FIG. 1 is a schematic diagram illustrating a schematic configuration of an engine system 100 including the two-stage supercharging system 1 of the present embodiment.
The engine system 100 is mounted on a vehicle or the like, the two-stage supercharging system 1,
An engine 101 (internal combustion engine), an intercooler 102, an EGR (Exhaust Gas Recirculation) valve 103, an EGR cooler 104, and an ECU (Engine Control Unit) 105 are provided.

The two-stage supercharging system 1 recovers energy contained in exhaust gas discharged from the engine 101 as rotational power, and generates compressed air to be supplied to the engine 101 by the rotational power.
The two-stage supercharging system 1 has the features of the present invention, and will be described in detail later with reference to the drawings.

  The engine 101 functions as a power source for the mounted vehicle. The engine 101 generates power by burning a mixture of compressed air and fuel supplied from the two-stage supercharging system 1 and combustion of the mixture. Is supplied to the two-stage supercharging system 1.

  The intercooler 102 cools the compressed air supplied from the two-stage supercharging system 1 to the engine 101, and is disposed between the two-stage supercharging system 1 and the intake port of the engine 101.

  The EGR valve 103 opens and closes a return flow path that returns a part of the exhaust gas discharged from the engine 101 to the intake side of the engine 101, and its opening degree is adjusted by the ECU 105.

  The EGR cooler 104 cools the exhaust gas that is returned to the intake side of the engine 101 via the return flow path, and is disposed on the upstream side of the EGR valve 103.

The ECU 105 controls the entire engine system 100.
In the engine system 100, the ECU 105 controls the above-described EGR valve 103 and an exhaust bypass valve device 5 described later in accordance with the rotational speed of the engine 101 (that is, the exhaust gas flow rate).

  In the engine system 100 having such a configuration, when the exhaust gas in which the air-fuel mixture is combusted in the engine 101 is exhausted, a part of the exhaust gas is returned to the intake side of the engine 101 via the EGR cooler 104. Most of the exhaust gas is supplied to the two-stage supercharging system 1. Then, compressed air is generated in the two-stage supercharging system 1, and the compressed air is cooled by the intercooler 102 and then supplied to the engine 101.

Next, the two-stage supercharging system 1 will be described in detail.
As shown in FIG. 1, the two-stage supercharging system 1 includes a low-pressure supercharger 2 (first supercharger), a high-pressure supercharger 3 (second supercharger), a check valve 4, The exhaust bypass valve device 5 and the waste gate valve 6 are provided.

The low-pressure stage supercharger 2 is arranged downstream of the high-pressure stage supercharger 3 in the exhaust gas flow direction, and is configured to be larger than the high-pressure stage supercharger 3.
The low-pressure supercharger 2 includes a low-pressure compressor 2a and a low-pressure turbine 2b.
The low-pressure compressor 2a includes a compressor impeller and a compressor housing that surrounds the compressor impeller and has an air passage formed therein.
The low-pressure stage turbine 2b includes a turbine impeller and a turbine housing that surrounds the turbine impeller and has an exhaust gas passage formed therein.
Then, the compressor impeller and the turbine impeller are connected by a shaft, and the turbine impeller is rotationally driven by the exhaust gas, whereby the compressor impeller is rotationally driven to generate compressed air.

The high-pressure supercharger 3 is arranged upstream of the low-pressure supercharger 2 in the exhaust gas flow direction.
The high pressure supercharger 3 includes a high pressure compressor 3a and a high pressure turbine 3b.
The high-pressure compressor 3a includes a compressor impeller and a compressor housing that surrounds the compressor impeller and has an air passage formed therein.
The high-pressure turbine 3b includes a turbine impeller and a turbine housing that surrounds the turbine impeller and has an exhaust gas passage formed therein.
Then, the compressor impeller and the turbine impeller are connected by a shaft, and the turbine impeller is rotationally driven by the exhaust gas, whereby the compressor impeller is rotationally driven to generate compressed air.

  In addition, as shown to Fig.2 (a), the turbine housing 2c of the low pressure stage turbine 2b and the turbine housing 3c of the high pressure stage turbine 3b are faced | matched and joined.

  Inside the turbine housing 3c of the high-pressure turbine 3b is an exhaust passage 3d for exhausting exhaust gas that has passed through the turbine impeller of the high-pressure turbine 3b, and for supplying the low-pressure turbine 2b without passing through the turbine impeller. A bypass channel 3e is provided.

  A supply flow path 2e for supplying exhaust gas to the turbine impeller 2d of the low-pressure turbine 2b is provided in the turbine housing 2c of the low-pressure turbine 2b.

  The turbine housing 2c of the low-pressure turbine 2b and the turbine housing 3c of the high-pressure turbine 3b are joined to connect the exhaust passage 3d, the bypass passage 3e, and the supply passage 2e.

  Returning to FIG. 1, the check valve 4 generates high-pressure compressed air discharged from the low-pressure compressor 2 a of the low-pressure supercharger 2 when the high-pressure compressor 3 a of the high-pressure supercharger 3 is not driven. It is provided in a bypass flow path that supplies the intake side of the engine 101 without going through the stage compressor 3a. As shown in FIG. 1, the check valve 4 allows the flow of compressed air from the low-pressure stage compressor 2a side to the engine 101 side, and the backflow of compressed air from the engine 101 side to the low-pressure stage compressor 2a side. Is configured to prevent.

The exhaust bypass valve device 5 opens and closes a bypass passage 3e for supplying the exhaust gas discharged from the engine 101 to the low pressure turbocharger 2 by bypassing the turbine impeller of the high pressure turbocharger 3. is there.
As shown in FIG. 2, the exhaust bypass valve device 5 includes a valve assembly 51, a mounting plate 52 (mounting portion), and an actuator 53.

FIG. 2B is an enlarged view of the valve assembly 51 and the mounting plate 52.
As shown in this figure, in the valve assembly 51, a valve body 51a that opens and closes an opening of the bypass passage 3e and a washer 51b that fixes the valve body 51a to the mounting plate 52 are connected via a shaft portion 51c. It has a configuration.
As shown in FIG. 2A, the valve assembly 51 rotates so as to open and close the opening of the bypass passage 3e in the boundary region between the turbine housing 2c of the low-pressure turbine 2b and the turbine housing 3c of the high-pressure turbine 3b. It is possible to move.

The valve body 51a has a lower surface 51d (a surface that contacts the opening of the bypass flow path 3e when closed) as a flat surface, and an upper surface 51e as a tapered surface that descends from the center toward the edge.
Moreover, in this embodiment, the through-hole is provided in the center part of the washer 51b, and the shaft part 51c provided in the center on the upper surface 51e side of the valve body 51a is inserted into the through-hole of the washer 51b. The tip of the shaft portion 51c is disposed so as to protrude from the washer 51b.
The shaft 51c and the washer 51b are fixed by joining the tip of the shaft 51c and the washer 51b by caulking.

The mounting plate 52 has a through hole 52a through which the shaft portion 51c is inserted. The shaft portion 51c is inserted through the through hole 52a and is sandwiched between the valve body 51a and the washer 51b.
Then, the mounting plate 52 is rotated as shown in FIG. 2A by transmitting the driving force from the actuator 53 via a link plate assembly (not shown). The valve assembly 51 is also rotated by the rotation of the mounting plate 52.

  Moreover, the edge part by the side of the valve body 51a of the through-hole 52a of the attachment plate 52 is made into the curved surface by carrying out R process, as shown in FIG.2 (b). The curved surface functions as a guide surface 52b for aligning the valve body 51a when the valve body 51a closes the opening of the bypass passage 3e.

More specifically, the valve body 51a is opened and closed when the bypass passage 3e is opened due to wear between the shaft portion 51c and the mounting plate 52 and a gap between the shaft portion 51c and the mounting plate 52 that are originally present. As a result, the positional relationship with the mounting plate 52 slightly changes.
That is, it acts on the valve body 51a when the bypass passage 3e opening shown by the solid line in FIG. 2A is closed and when the bypass passage 3e opening shown by the two-dot chain line in FIG. 2A is opened. The direction of gravity to be changed changes, whereby the positional relationship between the valve body 51a and the mounting plate 52 changes slightly.
Thus, since the valve body 51a becomes slightly movable with respect to the mounting plate 52, the positional relationship between the valve body 51a and the bypass flow path 3e opening changes when the bypass flow path 3e opening is closed. Then, the center position of the valve body 51a will be closed with a slight displacement from the operating force center L shown in FIG. 2B (the position where the driving force of the actuator 53 acts evenly on the entire periphery of the valve body 51a). And

At this time, in the present embodiment, the guide surface 52b provided on the mounting plate 52 abuts on the upper surface 51e of the valve body 51a and guides the valve body 51a, so that the center position of the valve body 51a becomes the operating force center L. The valve body 51a is aligned by matching.
For example, when the valve body 51a is displaced toward the rotation axis L1 of the mounting plate 52 shown in FIG. 2B, the guide surface 52b near the rotation axis L1 is used as the tapered surface of the valve body 51a. By contacting the upper surface 51e and pushing the upper surface 51e downward, the valve body 51a is pushed away from the rotation axis L1, thereby aligning the valve body 51a.
Further, when the valve body 51a is displaced in the direction away from the rotation axis L1, the guide surface 52b far from the rotation axis L1 comes into contact with the upper surface 51e of the valve body 51a and the upper surface 51e is moved downward. By pushing, the valve body 51a is pushed out in the direction approaching the rotation axis L1, thereby aligning the valve body 51a.

  Returning to FIG. 1, the wastegate valve 6 uses a part of the exhaust gas discharged from the high-pressure stage supercharger 3 or the exhaust gas discharged via the bypass passage 3 e as a turbine impeller of the low-pressure stage supercharger 2. Bypassing without passing through 2d, the opening degree is adjusted by the supercharging pressure of the ECU 105 or the low-pressure compressor 2a.

According to the two-stage supercharging system 1 of the present embodiment as described above, alignment of the valve body 51a is performed by the guide surface 52b when the valve body 51a closes the opening of the bypass flow path 3e.
For this reason, according to the two-stage supercharging system 1 of the present embodiment, when closing the bypass flow path 3e opening, the valve body 51a is always accurately arranged at a normal position with respect to the bypass flow path 3e opening. Can do.
Therefore, according to the two-stage supercharging system 1 of the present embodiment, the position of the valve body 51a can be arranged according to the operating force center L of the actuator 53, and the sealing performance of the valve body 51a is prevented from deteriorating. can do.

Further, in the two-stage supercharging system 1 of the present embodiment, the guide surface 52 b is provided on the surface of the mounting plate 52.
For this reason, alignment of the valve body 51a can be performed without installing a new member as alignment means.

In the two-stage supercharging system 1 of the present embodiment, the guide surface 52b is a curved surface.
For this reason, it becomes possible to reduce the frictional resistance between the valve body 51a and the guide surface 52b, and to guide the valve body 51a smoothly.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above-described embodiment, the configuration in which the edge portion of the through hole 52a of the mounting plate 52 is the guide surface 52b has been described.
However, the present invention is not limited to this. For example, as shown in FIG. 3, the mounting plate 52 is provided with a groove 52c surrounding a part of the valve body 51a, and the inner wall surface 52d of the groove 52c is provided. A guide surface for aligning the valve body 51a may be used.

In the above embodiment, the configuration in which the guide surface 52b is a curved surface has been described.
However, the present invention is not limited to this, and it is also possible to adopt a configuration in which the guide surface 52b is formed by a single plane or a plurality of planes having different angles.

In the above-described embodiment, the configuration in which the guide surface 52b, that is, the aligning means is provided on the surface of the mounting plate 52 has been described.
However, this invention is not limited to this, For example, it is also possible to employ | adopt the structure which attaches another member with respect to the attachment board 52, and uses the said another member as an alignment means.

Moreover, in the said embodiment, the structure provided with two superchargers was demonstrated.
However, the present invention is not limited to this, and a configuration including a plurality of superchargers can also be employed.

  1 …… Two-stage supercharging system (multi-stage supercharging system), 2 …… Low pressure supercharger (first supercharger), 2c …… Turbine housing, 2d …… Turbine impeller, 3 …… High pressure supercharger Machine (second turbocharger), 3c... Turbine housing, 3e .. bypass passage, 5 .. exhaust bypass valve device, 51... Valve assembly, 51a .. valve body, 51b. Shaft portion, 51d: lower surface, 51e: upper surface, 52: mounting plate (mounting portion), 52a: through hole, 52b ... guide surface (alignment means), 52c: groove portion, 52d: inner wall surface (Aligning means), 101 …… Engine (internal combustion engine)

Claims (3)

A first supercharger to which exhaust gas discharged from the internal combustion engine is supplied; a second supercharger disposed upstream of the flow of the exhaust gas from the first supercharger; and the internal combustion engine An exhaust bypass valve device that opens and closes a bypass passage that bypasses a turbine impeller of the second supercharger and supplies the exhaust gas to the first supercharger. ,
The exhaust bypass valve device includes:
A valve body for opening and closing the bypass passage opening;
A multistage supercharging system comprising: aligning means for aligning the valve body when the valve body closes the bypass passage opening. The exhaust bypass valve device includes an attachment portion to which the valve body is attached, and an actuator that opens and closes the valve body by rotating the attachment portion,
The multistage supercharging system according to claim 1, wherein the aligning means is a guide surface that is provided on a surface of the attachment portion and guides the valve body in contact with the valve body.   The multistage turbocharging system according to claim 2, wherein the guide surface is a curved surface.

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