JP2013007265A - Multistage supercharging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage supercharging system that stabilizes a flow of an exhaust gas flowing into a bypass duct, thus preventing a performance variation in an internal combustion engine.SOLUTION: The multistage supercharging system includes: a first supercharger to which the exhaust gas discharged from the internal combustion engine is supplied; a second supercharger disposed on the upstream of the first supercharger with respect to the flow of the exhaust gas; a valve body 51a that adjusts the opening degree of the bypass duct that supplies the exhaust gas discharged from the internal combustion engine to the first supercharger bypassing a turbine impeller of the second supercharger; and a stopper 10 that delineates the maximum opening degree of the valve body 51a.

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 this valve body is connected with the actuator via mediation members, such as a link board and an attaching part, and it is comprised so that it may open and close when the motive power of an actuator is transmitted.

Conventionally, when assembling a two-stage supercharging system, for example, the valve body is connected to the actuator by welding and joining the mediating members.
However, there may be variations in the relationship between the maximum displacement of the actuator and the maximum opening of the valve body after the valve body is installed due to individual differences in the actuator and mounting errors of the valve body and the mediating member.
Thus, if the relationship between the maximum displacement of the actuator and the maximum opening of the valve body varies, the maximum opening of the valve body will vary. The flow rate of the flowing exhaust gas, that is, the flow rate of the exhaust gas supplied to the low-pressure supercharger changes, resulting in performance variations in the internal combustion engine.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to stabilize the flow rate of exhaust gas flowing through a bypass passage 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 a valve body that adjusts an opening degree of 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. The supercharging system is configured to include a stopper that defines the maximum opening of the valve body.

  According to a second aspect of the present invention, in the first aspect of the present invention, the stopper is attached to the turbine housing and the attachment position relative to the turbine housing is adjustable.

  A third invention is the screw according to the second invention, further comprising a link plate for transmitting the power of the actuator to the valve body, wherein the stopper is screwed to the turbine housing and contacts the link plate. The structure of being a member is adopted.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the protrusion includes a mounting portion that is rotated by the actuator and to which the valve body is mounted, and the stopper is provided on the mounting portion and contacts the turbine housing. The configuration of being is adopted.

According to this invention, the stopper for prescribing | regulating the maximum opening degree of a valve body is provided separately. Since this stopper is used only for defining the maximum opening of the valve body, the maximum opening of the valve body can be defined without affecting other functions.
Therefore, according to the present invention, it is possible to install a stopper so that individual differences of actuators and valve body mounting errors are canceled, and variations occur in the relationship between the maximum displacement of the actuator and the maximum opening of the valve body. This can be prevented. Therefore, the maximum opening of the valve body when the actuator is displaced to the maximum is always the same, and the flow rate of the exhaust gas flowing through the bypass passage can be stabilized.

It is the schematic diagram and principal part sectional drawing containing the two-stage supercharging system in 1st Embodiment of this invention. It is the disassembled perspective view and side view containing the valve assembly and attachment plate with which the two-stage supercharging system in 1st Embodiment of this invention is provided. It is the perspective view and side view containing the valve assembly and attachment plate with which the two-stage supercharging system in 2nd Embodiment of this 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.

(First embodiment)
Fig.1 (a) is a schematic diagram which shows schematic structure of the engine system 100 provided with the two-stage supercharging system 1 of this 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. 1A, the two-stage supercharging system 1 includes a low-pressure supercharger 2 (first supercharger), a high-pressure supercharger 3 (second supercharger), and a check. A valve 4, an exhaust bypass valve device 5, and a 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 in FIG.1 (b), 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. 1A, the check valve 4 is a 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. Is provided in a bypass passage that supplies the air to the intake side of the engine 101 without passing through the high-pressure compressor 3a. As shown in FIG. 1 (a), the check valve 4 allows the flow of compressed air from the low-pressure stage compressor 2a side to the engine 101 side and compresses the engine 101 side to the low-pressure stage compressor 2a side. It is configured to prevent backflow of air.

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.
The exhaust bypass valve device 5 includes a valve assembly 51, a mounting plate 52 (mounting portion), a link plate assembly 53, and an actuator 54, as shown in FIG.

FIG. 2A is an exploded perspective view including the valve assembly 51, the mounting plate 52, and the link plate assembly 53.
FIG. 2B is an enlarged view of a main part of the turbine housing 3 c including the valve assembly 51, the mounting plate 52, and the link plate assembly 53.

As shown in FIG. 2A, the valve assembly 51 includes a valve body 51a that opens and closes the opening of the bypass passage 3e and a washer 51b that fixes the valve body 51a to the mounting plate 52 via a shaft portion 51c. It has a connected configuration.
As shown in FIG. 1 (b), the valve assembly 51 rotates so as to open and close the bypass flow path 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.

A through hole is provided at the center of the washer 51b, and the shaft 51c is inserted into the through hole of the washer 51b from above the valve body 51a, so that the tip of the shaft 51c protrudes from the washer 51b. Has been.
The shaft 51c and the washer 51b are fixed by welding the tip of the shaft 51c and the washer 51b.

The mounting plate 52 has a through hole through which the shaft portion 51c is inserted. The shaft portion 51c is inserted through the through hole, and is sandwiched between the valve body 51a and the washer 51b.
As shown in FIG. 2A, the mounting plate 52 is provided with a fitting hole 52a into which a stem 53b of a link plate assembly 53 described later is inserted.

As shown in FIG. 2A, the link plate assembly 53 includes a link plate 53a connected to the actuator rod 54a so that one end of the link plate assembly 53 is rotatable, and a stem 53b fixed to the other end of the link plate 53a. I have.
The stem 53 b penetrates the turbine housing 3 c and the tip is welded to the mounting plate 52 of the valve assembly 51.

  Here, when the actuator rod 54a moves in the left-right direction shown in FIG. 2B, the link plate 53a rotatably connected to the actuator rod 54a rotates about the stem 53b, and the link plate 53a rotates. As a result, the stem 53b and the mounting plate 52 are rotated, and the valve assembly 51 is also rotated.

And the two-stage supercharging system 1 of this embodiment is provided with the stopper 10 attached with respect to the turbine housing 3c, as shown in FIG.2 (b).
The stopper 10 prescribes | regulates the maximum rotation angle of the link board 53a, and prescribes | regulates the maximum opening degree of the valve body 51a by this.
In this embodiment, as shown in FIG. 2B, the stopper 10 is constituted by a screw member that is fixed by being screwed to the turbine housing 3c, and the tip abuts against the link plate 53a to link the link plate. By restricting the rotation of 53a, the maximum rotation angle of link plate 53a (that is, the maximum opening of valve body 51a) is defined.

The stopper 10 is screwed to the turbine housing 3c via a nut 11, and can be moved in the left-right direction in FIG. 2B by rotating the nut 11.
That is, in this embodiment, the stopper 10 is attached to the turbine housing 3c and the attachment position relative to the turbine housing 3c is adjustable.
By changing the mounting position of the stopper 10 with respect to the turbine housing 3c, the contact position between the stopper 10 and the link plate 53a changes, and the maximum opening degree of the valve body 51a can be adjusted.

  When a negative pressure operating actuator is used as the actuator 54, when assembling the two-stage turbocharging system 1 of the present embodiment, first, a set pressure for fully closing the valve body 51a is applied to the actuator 54. After that, the valve assembly 51, the mounting plate 52, and the link plate assembly 53 are connected by welding or the like. Thereafter, the pressure applied to the actuator 54 is gradually released, and the mounting position of the stopper 10 is adjusted so that the rotation angle of the valve body 51a becomes the maximum angle required in advance.

  Returning to FIG. 1A, the wastegate valve 6 allows the exhaust gas discharged from the high-pressure supercharger 3 or a part of the exhaust gas discharged via the bypass flow path 3 e to pass through the low-pressure supercharger 2. The turbine impeller 2d is bypassed and 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, the stopper 10 for defining the maximum opening degree of the valve body 51a is provided as a separate body. Since this stopper 10 is used only for defining the maximum opening of the valve body 51a, the maximum opening of the valve body 51a can be defined without affecting other functions.
Therefore, according to the two-stage supercharging system 1 of the present embodiment, the stopper 10 can be installed so that individual differences of the actuators 54 and mounting errors of the valve body 51a can be canceled, and the maximum displacement amount ( It is possible to prevent variation in the relationship between the stroke amount of the actuator rod 54a) and the maximum opening of the valve body 51a. Therefore, the maximum opening degree of the valve body 51a when the actuator 54 is displaced to the maximum is always the same, and the flow rate of the exhaust gas flowing through the bypass passage 3e can be stabilized.

Moreover, in the two-stage supercharging system 1 of this embodiment, the attachment position with respect to the turbine housing 3c of the stopper 10 can be adjusted.
For this reason, by finely adjusting the position of the stopper 10 at the time of assembly, it is possible to more reliably prevent variations in the relationship between the maximum displacement amount of the actuator 54 and the maximum opening degree of the valve body 51a.

Moreover, in the two-stage supercharging system 1 of this embodiment, the structure which the stopper 10 consists of a bolt member was employ | adopted.
For this reason, it is possible to easily adjust the position of the stopper 10 by rotating the nut 11.

  Further, in the two-stage turbocharging system 1 of the present embodiment, since the stopper 10 is attached to the outside of the turbine housing 3c, the stopper 10 is prevented from touching the exhaust gas, and corrosion of the stopper 10 is prevented. be able to.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the description of the present embodiment, the description of the same parts as those of the first embodiment is omitted or simplified.

FIG. 3A is a perspective view of the valve assembly 51 and the mounting plate 52 provided in the two-stage turbocharging system of the present embodiment.
FIG. 3B is a side view including the valve assembly 51, the mounting plate 52, and a part of the turbine housing 3c included in the two-stage turbocharging system of the present embodiment.

As shown in these drawings, the two-stage turbocharging system of the present embodiment includes a stopper 20 provided on the mounting plate 52 in place of the stopper 10 of the first embodiment.
In the present embodiment, the stopper 20 is formed of a protruding portion that comes into contact with the built-up portion 3c1 provided in the turbine housing 3c, and regulates the maximum opening of the valve body 51a by coming into contact with the built-up portion 3c1.

Also in the two-stage supercharging system of the present embodiment having such a configuration, the stopper 20 for defining the maximum opening degree of the valve body 51a is provided as a separate body. Since the stopper 20 is used only for defining the maximum opening of the valve body 51a, the maximum opening of the valve body 51a can be defined without affecting other functions.
Therefore, according to the two-stage supercharging system of the present embodiment, the stopper 20 can be installed so that the individual difference of the actuators 54 and the mounting error of the valve body 51a can be canceled, and the maximum displacement amount of the actuator 54 (actuator It is possible to prevent variation in the relationship between the stroke amount of the rod 54a) and the maximum opening of the valve body 51a. Therefore, the maximum opening degree of the valve body 51a when the actuator 54 is displaced to the maximum is always the same, and the flow rate of the exhaust gas flowing through the bypass passage 3e can be stabilized.

  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 embodiment, the configuration including two superchargers has been described.
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, 52... Mounting plate (mounting portion), 53... Link plate assembly, 53 a... Link plate, 10, 20... Stopper, 11.

Claims (4)

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 A multistage supercharging system comprising: a valve body that adjusts an opening degree of a bypass passage that bypasses a turbine impeller of the second supercharger and supplies the exhaust gas to be discharged to the first supercharger. ,
A multi-stage turbocharging system comprising a stopper that defines a maximum opening of the valve body.   The multistage turbocharging system according to claim 1, wherein the stopper is attached to the turbine housing and an attachment position with respect to the turbine housing is adjustable. A link plate for transmitting the power of the actuator to the valve body;
The multistage supercharging system according to claim 2, wherein the stopper is a screw member that is screwed into the turbine housing and abuts against the link plate. An attachment portion to which the valve body is attached while being rotated by an actuator;
The multistage turbocharging system according to claim 1, wherein the stopper is a protrusion provided on the mounting portion and abutting against the turbine housing.

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