JP6922339B2 - Supercharger - Google Patents

Description

The present invention relates to a supercharger.

A turbocharger equipped with a twin scroll turbine in which a double scroll is arranged around an impeller is known. For example, in the supercharger described in each patent document, two exhaust manifolds connected to a 4-cylinder engine are connected to each scroll. The exhaust gas that has passed through the exhaust manifold passes through the impeller while applying a rotational force to the impeller, and is discharged from the discharge flow path. Further, this type of turbocharger includes two bypass flow paths connecting each exhaust manifold and the discharge flow path, and a gate valve for opening and closing the bypass flow path. Under high-speed engine operation conditions, the gate valve is opened due to the engine back pressure limitation, and exhaust is also performed from the bypass flow path.

Japanese Unexamined Patent Publication No. 2013-2302 International Publication No. 2012/060187

In a turbocharger equipped with a twin scroll turbine, the area of the flow path cross section of each scroll may be different due to layout restrictions. In this type of form, when exhausting from the bypass flow path to suppress engine back pressure, if exhausting is performed from the bypass flow path, the engine back pressure when the fluid passes through each scroll varies, resulting in supercharging performance. Could be reduced.

An object of the present invention is to provide a supercharger capable of reducing a decrease in supercharging performance when the bypass flow path is open.

One aspect of the present invention is a supercharger provided with a flow path for discharging fluid that has passed through the impeller, and is a first scroll and a second scroll that are arranged around the impeller and have different cross-sectional areas of the flow path. , The first introduction flow path connected to the first scroll, the second introduction flow path connected to the second scroll, the first bypass flow path connected to the first introduction flow path and the discharge flow path, and A second bypass flow path connected to the second introduction flow path and the discharge flow path is provided, and the first scroll cross-sectional area, which is the area of the flow path cross section of the first scroll, is the flow path cross section of the second scroll. The first bypass cross-sectional area, which is larger than the area of the second scroll cross-section and is the area of the flow path cross-section of the first bypass flow path, is the area of the flow path cross-section of the second bypass flow path, which is the second bypass cross-sectional area. A supercharger, smaller than.

Conventionally, there has been no idea of designing the area of the flow path cross section of the bypass flow path in consideration of the area difference of the flow path cross sections of the two scrolls, and as a result, reducing the deterioration of the supercharging performance. On the other hand, in one aspect of the present invention, the area of the flow path cross section of the first scroll is larger than that of the second scroll, while the first bypass flow path corresponding to the first scroll has the second bypass flow. The area of the flow path cross section is smaller than that of the road. That is, when the area of the flow path cross section of the first bypass flow path is larger than that of the second bypass flow path, or when the area of the flow path cross section of both the first bypass flow path and the second bypass flow path is the same. By comparison, in the state where the first bypass flow path and the second bypass flow path are open, the variation in the engine back pressure when passing through the first scroll or the second scroll is reduced, and the deterioration of the supercharging performance can be reduced.

In some embodiments, the first scroll may be a hub-side scroll and the second scroll may be a shroud-side scroll. It may be advantageous to save space if the second scroll having a small cross-sectional area of the flow path is used as the scroll on the shroud side.

In some embodiments, the first scroll cross-sectional area and the second scroll cross-sectional area are the areas of the flow path cross-sections of the inlet portion, respectively, and the first bypass cross-sectional area and the second bypass cross-sectional area are of the exit portion, respectively. The area of the flow path cross section, which is the first effective area at the time of inflow derived from the first scroll cross-sectional area and the throat area of the impeller, and the second effective area at the time of inflow derived from the second scroll cross-sectional area and the throat area of the impeller. The difference between the total effective area at the time of inflow and the first bypass cross-sectional area and the total effective area at the time of the second inflow and the total cross-sectional area of the second bypass is smaller than the difference between the above and the supercharger. can. By deriving the first effective area at the time of inflow and the second effective area at the time of inflow, it becomes easier to quantitatively evaluate the degree of reduction of the variation in the engine back pressure, and the variation in the engine back pressure can be reduced more reliably. Therefore, the decrease in supercharging performance can be reduced.

In some embodiments, the first scroll cross-sectional area is Aa, the second scroll cross-sectional area is Ab, the impeller throat area is Ai, the first inflow effective area is Aaf, and the second inflow effective area is Abf. In addition, Aaf, which is the first effective area at the time of inflow, can be derived by the formula (1), and Abf, which is the effective area at the time of the second inflow, can be a supercharger derived by the formula (2).

According to some aspects of the present invention, it is possible to reduce a decrease in supercharging performance when the bypass flow path is open.

It is a figure which shows typically the supercharger system which includes the supercharger which concerns on embodiment. It is a perspective view which shows typically the flow path in a turbine housing. It is a schematic cross-sectional view when the twin scroll turbine is cut in the plane along the rotation axis. It is sectional drawing along the IV-IV line of FIG. It is a cross-sectional view of a shroud side scroll and a hub side scroll cut at a plane substantially orthogonal to the rotation axis, FIG. 3A is a cross-sectional view of the shroud side, and FIG. It is a figure for demonstrating the area of the flow path cross section at the entrance part of the shroud side scroll and the hub side scroll. It is a figure for demonstrating the throat area of a turbine impeller.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

The supercharger 2 is incorporated and applied to the supercharger system 1 of a ship, a vehicle, or the like, for example. As shown in FIG. 1, for example, a turbocharger system 1 of a 4-cylinder (multi-cylinder) engine (internal combustion engine) E includes an intake manifold 3 for distributing intake air to each cylinder Ea of the engine E. It is provided with an exhaust manifold 4 that is connected to the exhaust port of each cylinder Ea and that aggregates and discharges the exhaust gas G discharged from each exhaust port into two systems. Further, the supercharger 2 includes a compressor 5 connected to the intake manifold 3 via the suction path 1a and a twin scroll turbine 6 connected to the exhaust manifold 4. An intercooler, a throttle valve, and the like are arranged in the suction path 1a connecting the compressor 5 and the intake manifold 3.

The compressor 5 includes a compressor housing 5a and a compressor impeller 5b housed in the compressor housing 5a, and the twin scroll turbine 6 includes a turbine housing 7 and a turbine impeller 8 housed in the turbine housing 7. And have. The turbine impeller 8 is provided at one end of the rotating shaft 21, and the compressor impeller 5b is provided at the other end of the rotating shaft 21. A bearing housing (not shown) is provided between the turbine housing 7 and the compressor housing 5a. The rotating shaft 21 is rotatably supported by a bearing housing via a bearing, and the rotating shaft 21, the compressor impeller 5b, and the turbine impeller 8 rotate about the rotating axis X as an integral rotating body.

The compressor housing 5a is provided with a suction portion 5c and a discharge portion 5d. When the turbine impeller 8 rotates, the compressor impeller 5b rotates via the rotating shaft 21. The rotating compressor impeller 5b sucks in an external fluid (fluid) such as air through the suction section 5c, compresses it, and discharges it from the discharge section 5d. The compressed fluid discharged from the discharge unit 5d is supplied to the engine E via the suction path 1a and the intake manifold 3.

The turbine housing 7 has two exhaust gas introduction flow paths 7a and 7b connected to each of the two paths 4a and 4b of the exhaust manifold 4, and an exhaust gas discharge flow from which the exhaust gas G (fluid) that has passed through the turbine impeller 8 flows out. It is provided with a road (exhaust flow path) 7c. The exhaust gas G discharged from the engine E passes through the exhaust manifold 4 and flows into the turbine housing 7, rotates the turbine impeller 8, and then passes through the exhaust gas discharge flow path 7c and flows out of the turbine housing 7. do.

The turbine housing 7 is provided with two bypass flow paths 7d and 7e that divide a part of the exhaust gas G passing through the exhaust gas introduction flow paths 7a and 7b and discharge the exhaust gas to the exhaust gas discharge flow path 7c. The bypass flow paths 7d and 7e are connected to the exhaust gas introduction flow paths 7a and 7b and the exhaust gas discharge flow path 7c, respectively. A waist gate valve 9 for adjusting the flow rate by opening and closing the outlets of the bypass flow paths 7d and 7e is provided at the outlet portions of the bypass flow paths 7d and 7e, that is, the ends connected to the exhaust gas discharge flow path 7c. There is.

As shown in FIGS. 2, 3 and 4, the turbine housing 7 is provided with two scrolls 11 and 12 connected to the exhaust gas introduction channels 7a and 7b. The two scrolls 11 and 12 communicate with each other through the nozzle 13 (see FIG. 3) into the accommodation chamber 7f of the turbine impeller 8, and the accommodation chamber 7f of the turbine impeller 8 communicates with the exhaust gas discharge flow path 7c. There is. The two scrolls 11 and 12 are provided so as to overlap each other in the rotation axis X direction, and the scroll on the bearing housing side (compressor 5 side) of the rotation shaft 21 is the hub side scroll 11 and the scroll on the opposite side. Is the shroud side scroll 12. The hub-side scroll is sometimes called the rear-side scroll, and the shroud-side scroll is sometimes called the front-side scroll.

Since the hub-side scroll 11 and the shroud-side scroll 12 have the same basic form, the hub-side scroll 11 will be described as a representative. The hub-side scroll 11 draws a substantially spiral curve along the rotation direction of the turbine impeller 8 and forms a flow path whose diameter is gradually reduced from the upstream side to the downstream side when the flow direction of the exhaust gas G is used as a reference. doing. The downstream end of the hub-side scroll 11 is connected to the upstream side again to form a confluence portion that forms a recirculation flow of the exhaust gas G. In the present embodiment, the most upstream portion of the openings forming the confluence is the tongue portion 11a. A nozzle 13 communicating with the accommodation chamber 7f of the turbine impeller 8 is not provided in the portion upstream of the tongue portion 11a. Therefore, the portion provided with the tongue portion 11a is the entrance of the hub side scroll 11. It is a part.

Of the flow path cross sections of the hub side scroll 11, the flow path cross section when cut in a virtual plane passing through the tongue portion 11a is the flow path cross section of the inlet portion of the hub side scroll 11. More specifically, microscopically, the tongue portion 11a is a portion having a curved surface, assuming a tangential plane in contact with the tongue portion 11a, and a cross section of the flow path of the hub-side scroll 11 projected on the tangential plane. Assumed, the flow path cross section having the smallest area is the flow path cross section of the inlet portion of the hub side scroll 11. The flow path cross section of the inlet portion of the hub side scroll 11 is a flow path cross section (hub side representative cross section) Sa representing the flow path cross section of the hub side scroll 11 (see FIGS. 5 (b) and 6).

The shroud-side scroll 12 can be considered in the same manner as the hub-side scroll 11, and when a tangent plane in contact with the tongue portion 12a is assumed and the flow path cross section of the shroud-side scroll 12 projected on the tangent plane is assumed. In addition, the cross section of the flow path having the smallest area is the cross section of the flow path at the entrance portion of the scroll 12 on the shroud side. The flow path cross section of the inlet portion of the shroud side scroll 12 is a flow path cross section (shroud side representative cross section) Sb representing the flow path cross section of the shroud side scroll 12 (see FIGS. 5A and 6). be.

When comparing the hub-side representative cross-section Sa and the shroud-side representative cross-section Sb, in the present embodiment, the area of the hub-side representative cross-section Sa is larger than the area of the shroud-side representative cross-section Sb. The correlation between the hub-side representative cross-section Sa and the shroud-side representative cross-section Sb is only the same rotation angle with respect to the flow path cross-sections of other portions, for example, the tongue portions 11a and 12a. A similar conclusion can be drawn when comparing the cross-sections of the flow paths at the shifted positions. That is, in the present embodiment, the first scroll cross-sectional area, which is the area of the flow path cross section of the hub side scroll 11, is larger than the second scroll cross section, which is the area of the flow path cross section of the shroud side scroll 12.

As described above, the exhaust gas introduction channels 7a and 7b are connected to the hub side scroll 11 or the shroud side scroll 12, respectively. More specifically, the inlet portion of the hub side scroll 11, that is, the flow path on the upstream side of the tongue portion 11a is the exhaust gas introduction flow path 7a connected to the hub side scroll 11, and the inlet portion of the shroud side scroll 12 That is, the flow path on the upstream side of the tongue portion 12a is the exhaust gas introduction flow path 7b connected to the shroud side scroll 12. Hereinafter, for convenience of explanation, the exhaust gas introduction flow path connected to the hub side scroll 11 is referred to as a first introduction flow path 7a, and the exhaust gas introduction flow path connected to the shroud side scroll 12 is referred to as a second introduction flow path 7b.

Bypass flow paths 7d and 7e are connected to the first introduction flow path 7a and the second introduction flow path 7b, respectively. Hereinafter, for convenience of explanation, the bypass flow path connected to the first introduction flow path 7a is referred to as a first bypass flow path 7d, and the bypass flow path connected to the second introduction flow path 7b is referred to as a second bypass flow path 7e. Refer to. The first bypass cross-sectional area, which is the area of the flow path cross-sectional area Sx (see FIG. 4) of the first bypass flow path 7d, and the second bypass cross-sectional area, which is the area of the flow path cross-sectional area Sy of the second bypass flow path 7e, were compared. In this case, the first bypass cross-sectional area is smaller than the second bypass cross-sectional area. In this embodiment, the cross sections of the outlet ends opened and closed by the waist gate valve 9 are compared as the flow path cross section Sx of the first bypass flow path 7d and the flow path cross section Sy of the second bypass flow path 7e, respectively. However, the cross section of the portion of the first bypass flow path 7d having the smallest flow path area may be compared with the cross section of the portion of the second bypass flow path 7e having the smallest flow path area.

Here, regarding the relationship between the areas of the hub side representative cross section Sa and the shroud side representative cross section Sb, and the respective areas of the flow path cross section Sx of the first bypass flow path 7d and the flow path cross section S of the second bypass flow path 7e. It will be explained in more detail.

For example, the area of the hub-side representative cross-section Sa is the first scroll cross-section (Aa), the area of the shroud-side representative cross-section Sb is the second scroll cross-section (Ab), and the throat area of the turbine impeller 8 is (Ai). And. Further, the effective area when the exhaust gas G passing through the hub side scroll 11 passes through the turbine impeller 8 is the first effective area at the time of inflow (Aaf), and the exhaust gas G passing through the shroud side scroll 12 is the turbine impeller 8. Assuming that the effective area at the time of passing is the effective area at the time of the second inflow (Abf), the effective area at the time of the first inflow (Aaf) is derived by the equation (1), and the effective area at the time of the second inflow (Abf) is obtained. Derived by equation (2).

Here, the throat area (Ai) of the turbine impeller 8 will be described with reference to FIG. 7. As shown in FIG. 7, the outlet shroud diameter of the turbine impeller 8 is "D _4s ", the outlet hub diameter of the turbine impeller 8 is "D _4h ", and the blade angle on the outlet shroud side of the turbine impeller 8 is "D 4h". β _4s ”. In this case, the throat area (Ai) is a value defined by the equation (3).

Further, when the first bypass cross-sectional area (Ba) and the second bypass cross-sectional area (Bb) are used, the first effective area at the time of inflow (Aaf) and the second effective area at the time of inflow (Abf) are compared with each other. The difference between the total of the 1 effective inflow area (Aaf) and the 1st bypass cross-sectional area (Ba) and the total of the 2nd inflow effective area (Abf) and the 2nd bypass cross-sectional area (Bb) is smaller. There is. That is, this relationship means that the condition of the following equation (4) is satisfied. Satisfying this condition means that the engine back pressure (also referred to as "engine exhaust pressure") varies between the first effective area at inflow (Aaf) and the second effective area at inflow (Abf). Even if there is a difference between the two, it means that at least a part of the difference can be absorbed by the difference between the first bypass cross-sectional area (Ba) and the second bypass cross-sectional area (Bb).

In this embodiment, the actions and effects that can be enjoyed by satisfying the above relationships will be described. First, the exhaust gas G from the engine E alternately passes through the respective paths 4a and 4b of the exhaust manifold 4 and is introduced into the first introduction flow path 7a or the second introduction flow path 7b of the twin scroll turbine 6. The exhaust gas G introduced into the first introduction flow path 7a and the second introduction flow path 7b alternately flows through the hub side scroll 11 or the shroud side scroll 12, respectively, rotates the turbine impeller 8, and then the exhaust gas discharge flow path. It is discharged from 7c.

The above is the basic flow of the exhaust gas G. For example, under the high-speed operation condition of the engine E, the waist gate valve 9 is opened due to the engine back pressure limitation, and the first bypass flow path 7d and the second bypass flow path are used. Exhaust is also performed from 7e.

Here, for example, the area of the flow path cross section of the hub side scroll is larger than the area of the flow path cross section of the shroud side scroll, while the area of the flow path cross section of the first bypass flow path corresponding to the hub side scroll. And the form in which the area of the cross section of the flow path of the second bypass flow path corresponding to the scroll on the shroud side is substantially the same are verified as a comparative form. Since the area of the flow path cross section of the first bypass flow path and the second bypass flow path according to the comparative embodiment are substantially the same, the area difference of the flow path cross sections of the hub side scroll and the shroud side scroll is caused. There is no function to reduce the variation in engine back pressure that occurs. Even if the cross-sectional areas of the first bypass flow path and the second bypass flow path are different, if the first bypass flow path is larger than the second bypass flow path, rather, the engine back Pressure variability can be large.

On the other hand, in the present embodiment, the hub-side scroll 11 has a larger flow path cross-sectional area than the shroud-side scroll 12, but the first bypass flow path 7d corresponding to the hub-side scroll 11 has a shroud-side scroll. The area of the flow path cross section is smaller than that of the second bypass flow path 7e corresponding to 12. As a result, it functions to reduce the variation in engine back pressure that occurs when the hub side scroll 11 is ventilated and the shroud side scroll 12 is ventilated, although the degree is different. As a result, it is possible to reduce the decrease in supercharging performance due to the variation in engine back pressure.

In particular, in the present embodiment, the first effective inflow area Aaf derived from the first scroll cross-sectional area Aa and the throat area Ai of the turbine impeller 8 and the throat area Ai of the second scroll cross-sectional area Ab and the turbine impeller 8 Compared with the difference from the second effective area Abf at the time of inflow derived from The difference from the total is smaller. By deriving the first effective area Aaf at the time of inflow and the effective area Abf at the second inflow, it becomes easier to quantitatively evaluate the degree of reduction of the variation in the engine back pressure, and the variation in the engine back pressure is reduced more reliably. become able to.

Further, in the present embodiment, the flow path cross section of the shroud side scroll 12 is smaller than the area of the flow path cross section of the hub side scroll 11. By making the shroud side scroll 12 smaller than the hub side scroll 11, it may be advantageous to save space. As a modification of this embodiment, the area of the flow path cross section of the shroud side scroll 12 can be made larger than the area of the flow path cross section of the hub side scroll 11. In the case of this modified form, the area of the flow path cross section of the second bypass flow path corresponding to the shroud side scroll 12 is smaller than the area of the flow path cross section of the first bypass flow path corresponding to the hub side scroll 11. There is a need.

The present invention can be carried out in various forms having various modifications and improvements based on the knowledge of those skilled in the art, including the above-described embodiment. It is also possible to construct a modified example of each embodiment by utilizing the technical matters described in the above-described embodiment. The configurations of the respective embodiments may be combined and used as appropriate.

Further, the present invention is not limited to those applicable to automobile superchargers, and may be applied to ships and the like.

2 Supercharger 8 Turbine impeller
7a 1st introduction flow path 7b 2nd introduction flow path 7c Exhaust gas discharge flow path (discharge flow path)
7d 1st bypass flow path 7e 2nd bypass flow path 11 Hub side scroll (1st scroll)
12 Shroud side scroll (2nd scroll)
Sa flow path cross section (first scroll flow path cross section)
Sb flow path cross section (second scroll flow path cross section)
Sx flow path cross section (flow path cross section of the first bypass flow path)
Sy flow path cross section (flow path cross section of the second bypass flow path)
G Exhaust gas (fluid)

Claims (4)

A turbocharger equipped with a fluid discharge flow path that has passed through an impeller.
The first scroll and the second scroll, which are arranged around the impeller and have different cross-sectional areas of the flow path,
A first introduction flow path connected to the first scroll and a second introduction flow path connected to the second scroll.
A first bypass flow path connected to the first introduction flow path and the discharge flow path, and a second bypass flow path connected to the second introduction flow path and the discharge flow path are provided.
The area of the first scroll cross section, which is the area of the flow path cross section of the first scroll, is larger than the area of the second scroll cross section, which is the area of the flow path cross section of the second scroll.
First bypass cross-sectional area is the area of the flow passage cross section of the first bypass flow path, rather smaller than the second bypass cross-sectional area is the area of the flow passage cross section of the second bypass passage, and the first A supercharger in which the flow rate flowing out from the outlet of the bypass flow path is smaller than the flow rate flowing out from the outlet of the second bypass flow path. The supercharger according to claim 1, wherein the first scroll is a hub-side scroll, and the second scroll is a shroud-side scroll. The first scroll cross-sectional area and the second scroll cross-sectional area are the areas of the flow path cross sections of the inlet portions, respectively.
The first bypass cross-sectional area and the second bypass cross-sectional area are the areas of the flow path cross sections of the outlet portions, respectively.
The difference between the first effective area at the time of inflow derived from the first scroll cross-sectional area and the throat area of the impeller and the second effective area at the time of inflow derived from the second scroll cross-sectional area and the throat area of the impeller. compared,
The excess according to claim 1 or 2, wherein the difference between the total of the first effective area at the time of inflow and the first bypass cross-sectional area and the total of the second effective area at the time of inflow and the second bypass cross-sectional area is smaller. Feeder. When the first scroll cross-sectional area is Aa, the second scroll cross-sectional area is Ab, the throat area of the impeller is Ai, the first inflow effective area is Aaf, and the second inflow effective area is Abf. The supercharger according to claim 3, wherein Aaf, which is the first effective area at the time of inflow, is derived by the formula (1), and Abf, which is the effective area at the time of the second inflow, is derived by the formula (2). ..

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