JP2012087685A - Turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbocharger capable of efficiently recovering exhaust energy.SOLUTION: A turbine wheel 30 has a body part 31 and a blade part 32. The blade part 32 is constituted of a first blade 33 and a second blade 34 planarly extending from the body part 31 to the radial outside. The length of a first trailing edge 333 of the first blade 33 is L1 and the length of the second trailing edge 343 of the second blade 34 is L2, and so the L1 is different from the L2. Thus, choke due to an increase in the flow rate of exhaust gas can be inhibited. When the flow rate of the exhaust gas is small, the energy of the exhaust gas can be efficiently recovered, and when the flow rate of the exhaust gas is large, the flow disturbance of the exhaust gas can be inhibited.

Description

  The present invention relates to a turbocharger used in an engine supercharging system.

Conventionally, a turbine wheel is rotated by an exhaust flow of an engine, and a compressor wheel connected to the turbine wheel via a shaft is rotated to supercharge air in an intake passage to a combustion chamber of the engine. Turbochargers that improve output are known.
In the turbocharger of Patent Document 1, the turbine housing has a first scroll flow path and a second scroll flow path. The turbine wheel includes a main body portion and a plurality of blades extending in the axial direction, and faces the first inflow portion facing the first scroll flow path and the second scroll flow path. A second inflow portion. Here, the number of blades provided in the second inflow portion of the turbine wheel is smaller than the number of blades provided in the first inflow portion. That is, the throat area is increased by notching some of the plurality of blades to the main body at the second inflow portion. This suppresses exhaust choke during high load.

JP2007-192172

However, in the turbocharger, since some blades are cut out to the main body at the second inflow portion, when the exhaust flow rate is small, the exhaust energy recovery efficiency may be reduced. Further, when the exhaust gas flow rate is large, the exhaust gas flowing in from the first scroll channel and the exhaust gas flowing in from the second scroll channel merge at the notch portion of the blades, thereby disturbing the exhaust flow and recovering the exhaust energy. Efficiency may be reduced.
The present invention has been made in view of the above-described problems, and an object thereof is to provide a turbocharger having high exhaust energy recovery efficiency.

  The invention according to claim 1 includes a compressor, a turbine wheel, a turbine housing, and a flow rate adjusting means. The compressor has a compressor wheel that compresses the intake air. The turbine wheel has a main body portion and a blade portion. The main body is provided coaxially with the compressor wheel and rotates integrally with the compressor wheel. The blade portion is composed of a first blade and a second blade extending in a plate shape from the main body portion radially outward. The turbine housing has a housing portion, a first passage, and a second passage. The accommodating portion forms an internal space for accommodating the turbine wheel. The first passage opens into the internal space and the exhaust flows. A 2nd channel | path opens to the opposite side to the axial compressor of a main-body part rather than the opening of a 1st channel | path among internal spaces, and exhaust_gas | exhaustion distribute | circulates. The flow rate adjusting means can adjust the flow rate of the exhaust gas flowing through the second passage.

The first blade includes a first leading edge that faces the opening of the first passage, a first tip that faces the opening of the second passage, and a main body portion from an end of the first tip opposite to the first leading edge. And a first trailing edge extending toward the rotation axis of the.
The second blade has a second leading edge that faces the opening of the first passage, a second tip that faces the opening of the second passage, and a main body portion from the end of the second tip opposite to the second leading edge. And a second trailing edge extending toward the rotation axis.
Here, if the length of the first trailing edge is L1, and the length of the second trailing edge is L2, the lengths of L1 and L2 are different.

  Thereby, the distance from the main body of the portion of the second blade facing the opening of the second passage of the second tip, and the main portion of the portion of the first blade facing the opening of the second passage of the first tip. The distance is different. That is, a part of the first tip of the first blade or the second tip of the second blade is cut away at a location facing the opening of the second passage. For this reason, the throat area of the position facing the opening of the second passage increases. Therefore, when exhaust flows into the internal space from the second passage, choke due to an increase in the flow rate of the exhaust can be suppressed.

Further, the first chip or the second chip is formed such that a portion facing the opening of the second passage extends from the main body portion by a predetermined length in the radially outward direction. For this reason, the flow path of the exhaust between the first blade and the second blade is formed from one end to the other end in the axial direction of the side surface of the main body. Therefore, when exhaust flows through the flow path of the exhaust between the first blade and the second blade, the exhaust is continuously pressed against the first blade and the second blade from one end to the other end in the axial direction of the side surface of the main body. Pressure can be applied. Therefore, even when the flow rate of the exhaust gas is small, the energy of the exhaust gas that has entered from the first passage can be efficiently recovered.
And when the flow rate of the exhaust gas is large, even if the exhaust gas flows in from the second passage, the flow of the exhaust gas flowing through the exhaust passage between the first blade and the second blade facing the opening of the second passage, The exhaust gas flowing in from the second passage is rectified, and the disturbance of the exhaust flow is suppressed. Therefore, the energy of the exhaust gas flowing in from the first passage and the second passage can be efficiently recovered.

According to the invention which concerns on Claim 2, the 1st blade | wing and the 2nd blade | wing are formed so that the relationship of 0.1 <= L2 / L1 <= 0.5 may be satisfy | filled.
As a result, the effect of suppressing choke due to an increase in the exhaust flow rate, the effect of efficiently recovering the exhaust energy when the exhaust flow rate is low, and the effect of suppressing the disturbance of the exhaust flow when the exhaust flow rate is high are enhanced. Can do.

According to a third aspect of the present invention, the portion of the second tip that faces the opening of the second passage is located at a position facing the first passage side end of the opening of the second passage of the second blade from the second trailing. It is formed on the side of the main body from a virtual straight line connecting to the end of the edge opposite to the main body.
Thereby, when exhaust flows in from the second passage, the effect of suppressing choke due to an increase in the exhaust flow rate can be further enhanced.

According to the fourth aspect of the present invention, the same number of first blades and second blades are alternately arranged in the circumferential direction of the main body.
Therefore, the effect of efficiently recovering the exhaust energy can be further enhanced.

The schematic diagram which shows the outline of the gasoline engine system to which the turbocharger of one Embodiment of this invention is applied. The fragmentary sectional view by the side of the turbine wheel of the turbocharger of one embodiment of the present invention. The principal part sectional drawing of the turbine wheel side of the turbocharger of one Embodiment of this invention. The top view which shows the turbine wheel of the turbocharger of one Embodiment of this invention. The side view which shows the turbine wheel of the turbocharger of one Embodiment of this invention.

Hereinafter, a turbocharger according to an embodiment of the present invention will be described with reference to FIGS.
(One embodiment)
A gasoline engine system to which a turbocharger according to an embodiment of the present invention is applied is shown in FIG. The gasoline engine system 1 includes an intake pipe 11, a turbocharger 10, an internal combustion engine (hereinafter referred to as “engine”) 12, an exhaust pipe 13, an electronic control device 14, a throttle 15, an intercooler 16, and the like, and is mounted on a vehicle. Has been.

In the case of this embodiment, the turbocharger 10 includes a compressor 20, a turbine wheel 30, a turbine housing 40, a flow rate adjusting means 50, and the like.
The compressor 20 is provided in the middle of the intake pipe 11. The compressor 20 has a compressor housing 21 and a compressor wheel 22 accommodated in the compressor housing 21. The compressor 20 compresses the intake air taken in from the intake pipe 11 by the rotation of the compressor wheel 22 and supplies the compressed air to the engine 12.

  As shown in FIG. 2, the turbine housing 40 includes a housing portion 45, an annular passage portion 44, and an inlet portion 43.

The accommodating part 45 is substantially cylindrical and has a shaft hole 47, an accommodating recess 48, and an exhaust outlet 49. The accommodating portion 45 has a substantially cylindrical inner space 450 formed therein. The shaft hole 47 is formed at the center of one end of the housing portion 45 in the axial direction. The shaft 100 is inserted into the shaft hole 47. The housing recess 48 is formed on the shaft hole 47 side of the inner wall of the turbine housing 40. The exhaust outlet 49 is formed at the center of the outer wall of the turbine housing 40 opposite to the shaft hole 47. In the present embodiment, the shaft hole 47, the housing recess 48, and the exhaust outlet 49 are formed coaxially.
The annular passage portion 44 is formed on the outer diameter side of the housing portion 45.
The inlet portion 43 is formed so as to protrude from the outer wall of the annular passage portion 44 and has an exhaust inlet 431.

  A space inside the inlet portion 43 and the annular passage portion 44 is divided by the partition portion 46, thereby forming a first passage 41 and a second passage 42. The first passage 41 has a linear inlet passage 411 and an annular first annular passage 412. The second passage 42 includes a linear inlet passage 421 and an annular second annular passage 422. The first annular passage 412 has a first annular opening 413 on the radially inner side, and the second annular passage 422 has a second annular opening 423 on the radially inner side. The second annular passage opening 423 is formed closer to the discharge port 48 than the first annular opening 413 in the axial direction of the shaft 100. Here, “the opening of the first passage” in the claims corresponds to the first annular opening 413, and “the opening of the second passage” corresponds to the second annular opening 423.

  The flow rate adjusting means 50 is provided in the second inlet passage 421 of the inlet portion 43 and adjusts the flow rate of the exhaust gas flowing through the second passage 42.

The turbine wheel 30 is accommodated in the internal space 450 of the accommodating portion 45 of the turbine housing 40 and has a main body portion 31 and a blade portion 32.
The main body 31 is substantially conical and has a side surface 311 and a bottom surface 312. The side surface 311 is formed to be curved and recessed inside the main body 31. The shaft 100 is connected to the bottom surface 312 at the center. The main body 31 is provided coaxially with the compressor wheel 22 via the shaft 100, and can rotate integrally with the compressor wheel 22 (see FIG. 1).

  The blade portion 32 includes a first blade 33 and a second blade 34 that extend radially outward from the side surface 311 of the main body portion 31. The first blades 33 and the second blades 34 are formed from one end to the other end in the axial direction of the side surface 311 and are alternately arranged in the same number along the circumferential direction of the main body 31 (see FIGS. 4 and 5).

  As shown in FIG. 2, the first blade 33 has a plate shape having a first leading edge 331, a first tip 332, a first trailing edge 333, and a first hub 334. The first leading edge 331 faces the first annular opening 413. The first chip 332 faces the second annular opening 423 and the radially inner end 461 of the partition 46. The first trailing edge 333 is formed to extend from the end of the first tip 332 opposite to the first leading edge 331 toward the rotation axis of the main body 31. The first hub 334 is formed along the side surface 311 from the end of the first leading edge 331 opposite to the first tip 332 to the end of the first trailing edge 333 opposite to the first tip 332. Has been.

  The second blade 34 has a second leading edge 341, a second tip 342, a second trailing edge 343, and a second hub 344 as a second base. The second leading edge 341 faces the first annular opening 413. The second chip 342 is opposed to the second annular opening 423 and the radially inner end 461 of the partition 46 and has a step 345. The step portion 345 faces the second annular opening 423. Further, the stepped portion 345 is formed so as to be positioned closer to the main body portion 31 than the first tip 332 facing the second annular opening 423 of the second annular passage 422. The second trailing edge 343 is formed to extend from the end of the second tip 342 opposite to the second leading edge 341 toward the rotation axis of the main body 31. The second hub 344 is formed along the side surface 311 from the end of the second leading edge 341 opposite to the second tip 342 to the end of the second trailing edge 343 opposite to the second tip 342. Has been. Here, the step portion 345 corresponds to “a portion of the second chip facing the opening of the second passage” in the claims.

  As shown in FIG. 3, the first trailing edge 333 and the second trailing edge 343 are formed to be located closer to the exhaust outlet 49 than the end of the second annular opening 423 on the exhaust outlet 49 side. Further, since the step 345 is formed on the second chip 342, the length of the second trailing edge 343 is shorter than the length of the first trailing edge 333. In the case of the present embodiment, when the length of the first trailing edge 333 is L1 and the length of the second trailing edge 343 is L2, the first trailing edge 333 and the second trailing edge 343 are 0. It is formed so as to satisfy the relationship of 1 ≦ L2 / L1 ≦ 0.5.

  Further, in the present embodiment, the step portion 345 of the second tip 342 is formed on the second trailing edge 343 from the position of the second blade 34 facing the end P of the second annular opening 423 on the first annular passage 412 side. It is formed closer to the main body 31 than a virtual straight line Q connecting to the end opposite to the main body 31.

Next, the operation of the turbocharger 10 according to the present embodiment will be described.
The second inlet passage 421 is closed by the flow rate adjusting means 50 at the time of low speed and low load operation where the exhaust flow rate is small. Therefore, the exhaust gas is guided only to the first passage 41. Exhaust gas flows from the first passage 41 into the internal space 450 of the accommodating portion 45. Exhaust gas that has flowed into the internal space 450 flows along the arrow H <b> 1, and applies pressure to the first blade 33 and the second blade 34 that are formed from one end to the other end of the side surface 311 in the axial direction. Therefore, exhaust energy can be efficiently recovered by the first blade 33 and the second blade 34.

Further, the opening degree of the flow rate adjusting means 50 is set to be large during high speed and high load operation with a large exhaust flow rate. At this time, the exhaust gas is guided separately into the first passage 41 and the second passage 42.
As shown in FIG. 3, the exhaust gas flowing along the arrow H <b> 1 applies a relatively large pressing pressure to the first blade 33 and the second blade 34 from one end to the other end of the side surface 311 in the axial direction.

  On the other hand, the exhaust gas that has entered through the second passage 42 flows into the internal space 450 along the arrow H3, and then merges with the exhaust gas that enters through the first passage 41 and flows along the arrow H2. The merged exhaust gas is rectified into an exhaust flow flowing along the arrow H1 and flows along the arrow H4. Therefore, the combined exhaust gas is discharged from the exhaust outlet 49 while applying a pressing pressure to the first blade 33 without disturbing the flow.

  Exhaust gas exerts a rotational force on the turbine wheel 30 by applying a pressing pressure to the first blade 33 and the second blade 34. The turbine wheel 30 that is rotated by the pressing pressure applied to the first blade 33 and the second blade 34 transmits a rotational force to the compressor wheel 22 formed on the same axis. Then, the intake air is pressurized by the rotation of the compressor wheel 22 and supplied to the engine 12 (see FIG. 1).

Here, for example, when the first trailing edge 333 and the second trailing edge 343 are formed to satisfy the relationship of L2 / L1 <0.1, the second tip 342 faces the second annular opening 423. The portion to be formed is extremely short from the main body portion 31 in the radially outward direction. For this reason, when exhaust flows along the flow path between the 1st blade | wing 33 and the 2nd blade | wing 34 along the arrow H1, the area of the part which receives the pressing pressure of the exhaust_gas | exhaustion of the 2nd blade | wing 34 becomes small. Therefore, when the flow rate of the exhaust gas is small, there is a possibility that the energy recovery efficiency of the exhaust gas is reduced.
Then, the exhaust gas flowing in from the second passage 42 and the exhaust gas flowing in from the first passage 41 merge at a location facing the second annular opening 423, and the exhaust flow is disturbed, which may reduce the exhaust energy recovery efficiency. There is.

  Further, for example, when the first trailing edge 333 and the second trailing edge 343 are formed so as to satisfy the relationship of L2 / L1> 0.5, the throat area at the location facing the second annular opening 423 is reduced by half. There is a risk. Therefore, when exhaust flows from the second passage 42, choke may occur due to an increase in the flow rate of the exhaust.

  In the present embodiment, the second blade 34 has a stepped portion 345 located on the radially inner side of the first tip 332 at a position facing the second annular opening 423. The first trailing edge 333 and the second trailing edge 343 are formed so as to satisfy the relationship of 0.1 ≦ L2 / L1 ≦ 0.5. As a result, the second tip 342 of the second blade 34 is partially cut away at a location facing the second annular opening 423. For this reason, the throat area of the position facing the second annular opening 423 increases. Therefore, a buffer space is formed on the opposite side of the stepped portion 345 from the second hub 344, and when exhaust flows from the second passage 42, choke due to an increase in the flow rate of exhaust can be suppressed.

  Further, the second chip 342 is formed such that a portion facing the second annular opening 423 extends from the main body portion 31 in a radially outward direction by a predetermined length. Thereby, the flow path between the 1st blade | wing 33 and the 2nd blade | wing 34 is formed from the one end of the axial direction of the side surface 311 to the other end along arrow H1. For this reason, when the exhaust gas flows along the flow path between the first blade 33 and the second blade 34 along the arrow H1, the first blade 33 and the second blade are connected from one end to the other end of the side surface 311 in the axial direction. A continuous pressing pressure can be applied to the blades 34. Therefore, when the flow rate of the exhaust gas is small, the energy of the exhaust gas flowing in from the first passage 41 can be efficiently recovered by the first blade 33 and the second blade 34, and the recovery efficiency of the exhaust energy can be increased.

  Further, when the flow rate of the exhaust gas is large, the exhaust gas flowing in from the second passage 42 is rectified by the flow of the exhaust gas flowing along the arrow H1. The rectified exhaust flows along the arrow H4 and presses against the first blade 33 to apply pressure. Therefore, disturbance of the exhaust flow can be suppressed, and the energy of the exhaust gas flowing from the second passage 42 can be efficiently recovered.

  In the present embodiment, the step portion 345 of the second tip 342 is a main body portion of the second trailing edge 343 from a position facing the end portion P of the second annular opening 423 of the second blade 34 on the first annular passage 412 side. It is formed closer to the main body 31 than the imaginary straight line Q connecting to the end opposite to the end 31. Thereby, the volume of the buffer space formed on the opposite side of the stepped portion 345 from the second hub 344 can be increased. Therefore, when exhaust flows from the second passage 42, the effect of suppressing choke due to an increase in the exhaust flow rate can be enhanced.

(Other embodiments)
In the above-described embodiment, the step portion is cut into a substantially L shape. On the other hand, in another embodiment, a portion from the position facing the end on the first annular passage side of the second annular opening of the second blade to the end opposite to the main body of the second trailing edge is connected. As long as it is formed closer to the main body than the virtual straight line, it may be cut out in any shape.
In the above-described embodiment, the same number of first blades and second blades are alternately arranged. On the other hand, in other embodiments, the first blades and the second blades may be alternately arranged in different numbers.
In the above-described embodiment, the turbocharger is applied to a gasoline engine system. On the other hand, in another embodiment, the turbocharger may be applied to a diesel engine system.
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 10 ... Turbocharger 20 ... Compressor 21 ... Compressor housing 22 ... Compressor wheel 30 ... Turbine wheel 31 ... Main-body part 32 ... Blade | wing part 33 ... 1st blade | wing 34 Second blade 40 ... Turbine housing 41 ... First passage 42 ... Second passage 50 ... Flow rate adjusting means 331 ... First leading edge 332 ... First tip 333 First trailing edge 341 ... second leading edge 342 ... second tip 343 ... second trailing edge 450 ... internal space

Claims (4)

A compressor having a compressor wheel for compressing intake air;
A turbine wheel having a main body portion that is provided coaxially with the compressor wheel and that rotates integrally with the compressor wheel, and a blade portion that includes first and second blades extending radially outward from the main body portion, and
An accommodating portion that forms an internal space for accommodating the turbine wheel, a first passage that opens into the internal space and through which exhaust flows, and an axial direction of the main body portion relative to an opening of the first passage in the internal space. A turbine housing having a second passage that opens to the opposite side of the compressor and through which exhaust flows;
A flow rate adjusting means capable of adjusting a flow rate of the exhaust gas flowing through the second passage,
The first blade has a first leading edge facing the opening of the first passage, a first tip facing the opening of the second passage, and an opposite side of the first leading edge of the first tip. A first trailing edge extending from an end toward the rotation axis of the main body,
The second blade has a second leading edge facing the opening of the first passage, a second tip facing the opening of the second passage, and a side opposite to the second leading edge of the second tip. A second trailing edge extending from the end toward the rotation axis of the main body,
A turbocharger, wherein the length of the first trailing edge is L1, and the length of the second trailing edge is L2, L1 and L2 are different in length.   2. The turbocharger according to claim 1, wherein the first blade and the second blade are formed to satisfy a relationship of 0.1 ≦ L2 / L1 ≦ 0.5.   The portion of the second tip that faces the opening of the second passage is located at a position facing the first passage side end of the opening of the second passage of the second blade, and the main body of the second trailing edge. The turbocharger according to claim 2, wherein the turbocharger is formed closer to the main body than a virtual straight line connecting up to an end opposite to the portion.   The turbocharger according to any one of claims 1 to 3, wherein the same number of the first blades and the second blades are alternately arranged in the main body.

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