JP2017166439A - Turbine, and turbo charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine capable of suppressing the deterioration of turbine efficiency, and a turbo charger equipped with the turbine.SOLUTION: A turbine 10 and a turbo charger have a turbine rotor equipped with a rotor shaft 16 and a turbine wheel 18; a turbine housing 14 to which exhaust of an internal combustion engine is sent; a primary nozzle 30 which makes the exhaust in the turbine housing 14 flow out to a flow path 22 between blades; a secondary nozzle 32 which makes the exhaust in the turbine housing 14 selectively flow out to the flow path 22 between blades according to a rotation number of the internal combustion engine; and a partition wall 42 which partitions the primary nozzle 30 and the secondary nozzle 32. An inside end portion 42A of the partition wall 42 is positioned on the inner side in a radial direction of the rotor shaft 16 than an outlet end portion of the primary nozzle 30, and is positioned on the outer side in the radial direction of the rotor shaft 16 than a line connecting an end portion on a shroud side at the outlet end portion of the primary nozzle 30 and an end portion on a hub side on an outer peripheral portion 18A of the turbine wheel 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a turbine used for supercharging an internal combustion engine and a turbocharger including the turbine.

  There is known a turbocharger that rotates a turbine rotor by flowing exhaust gas of an internal combustion engine through a flow path between blades of a turbine wheel. In this turbocharger, for example, Patent Document 1 includes a fixed nozzle and a variable nozzle separated by a partition wall, and when the internal combustion engine rotates at low speed, exhaust gas flows from only the fixed nozzle to the inter-blade flow path so that the internal combustion engine rotates at a medium to high speed. Sometimes, a turbocharger that causes exhaust gas to flow from the variable nozzle to the flow path between the blades is also disclosed.

JP 2007-192124 A

  In the turbocharger of Patent Document 1, since the inner peripheral end of the partition wall and the outlet end of the fixed nozzle are in substantially the same position in the radial direction of the rotor shaft, the exhaust gas that has passed through the fixed nozzle flows backward to the movable nozzle side. Easy to do. Further, since the inner peripheral end of the partition wall and the outlet end of the fixed nozzle are positioned close to the blades of the turbine wheel, the exhaust gas that has passed through the fixed nozzle hits only a part of the blades of the turbine wheel.

  In view of the above facts, an object of the present invention is to provide a turbine capable of suppressing a decrease in turbine efficiency and a turbocharger including the turbine.

  The turbine according to claim 1, comprising a rotor shaft, and a turbine wheel having a plurality of rotor blades forming an inter-blade flow path and provided on one axial side of the rotor shaft, and A turbine housing that is provided around the turbine wheel and into which exhaust gas from an internal combustion engine is sent, a primary nozzle that is provided in the turbine housing and flows out the exhaust gas in the turbine housing to the inter-blade passage, and is provided in the turbine housing A secondary nozzle that selectively allows exhaust in the turbine housing to flow into the inter-blade flow path according to the rotational speed of the internal combustion engine, and the primary nozzle and the secondary nozzle provided in the turbine housing. And an inner end portion of the partition wall in the radial direction of the rotor shaft is more than the outlet end portion of the primary nozzle. The inner end of the primary nozzle and the end portion on the shroud side which is one side in the axial direction of the rotor shaft at the outlet end portion of the primary nozzle and the other side in the axial direction of the rotor shaft at the outer peripheral portion of the turbine wheel. From a line connecting an end on a certain hub side, or a line connecting an end on the hub side at the outlet end of the primary nozzle and an end on the shroud side in the outer peripheral portion of the turbine wheel Located radially outward.

  According to the said structure, the inner side edge part of the partition which separates a primary nozzle and a secondary nozzle is located in the radial inside of a rotor axis | shaft from the exit edge part of a primary nozzle. The inner end of the partition wall is a line connecting the shroud end at the outlet end of the primary nozzle and the hub end at the outer periphery of the turbine wheel or the hub end at the outlet end of the primary nozzle. It is located on the outer side in the radial direction from the line connecting the end portion on the shroud side in the outer peripheral portion of the turbine wheel.

  For this reason, the backflow of the exhaust to the secondary nozzle side is suppressed, and the width for receiving the exhaust in the rotor blade of the turbine wheel is widened. Therefore, the flow of exhaust gas from the primary nozzle to the inter-blade flow path becomes smooth, and a decrease in turbine efficiency can be suppressed.

  The turbine according to claim 2 is the turbine according to claim 1, wherein the primary nozzle and the secondary nozzle are arranged in parallel along an axial direction of the rotor shaft, and the primary nozzle is disposed on the shroud side. The secondary nozzle is on the hub side.

  According to the above configuration, since the primary nozzle is disposed on the shroud side and the secondary nozzle is disposed on the hub side, the primary nozzle is disposed on the hub side and the secondary nozzle is disposed on the shroud side. The reverse flow rate of the exhaust gas to the secondary nozzle side is reduced. For this reason, the fall of turbine efficiency can be suppressed.

  The turbine according to claim 3 is the turbine according to claim 1 or 2, wherein the primary nozzle and the secondary nozzle are provided with a plurality of nozzle vanes, and the outlets of the nozzle vane at the primary nozzle and the secondary nozzle are provided. The outer peripheral shape on the side is a curved shape along a logarithmic spiral.

  According to the above configuration, since the outer peripheral shape of the outlet side of the primary nozzle and the secondary nozzle of the nozzle vane is a curved shape along the logarithmic spiral, the flow of exhaust gas from the primary nozzle and the secondary nozzle to the inter-blade flow path As compared with a nozzle vane having a linear outer peripheral shape, it is possible to suppress a decrease in turbine efficiency.

  A turbocharger according to a fourth aspect includes the turbine according to any one of the first to third aspects.

  According to the said structure, since the turbocharger is provided with the turbine which has the said characteristic, the fall of turbine efficiency can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the turbine which can suppress the fall of turbine efficiency and a turbocharger provided with this can be provided.

It is sectional drawing which cut | disconnected the turbine and turbocharger which concern on 1st Embodiment of this invention along the axial direction. (A) is the sectional view on the AA line in FIG. 1, (B) is the sectional view on the BB line in FIG. 1, (C) is an enlarged view of a nozzle vane. It is explanatory drawing which shows typically the primary nozzle of the turbine and turbocharger which concern on 1st Embodiment of this invention, a secondary nozzle, a partition, and a turbine rotor. (A) is explanatory drawing equivalent to FIG. 3 which shows the flow of the exhaust in a comparative example, (B) is explanatory drawing equivalent to FIG. 3 which shows the flow of exhaust in 1st Embodiment of this invention. (A) is explanatory drawing equivalent to FIG. 3 which shows the flow of the exhaust in a comparative example, (B) is explanatory drawing equivalent to FIG. 3 which shows the flow of exhaust in 2nd Embodiment of this invention. (A) is explanatory drawing equivalent to FIG. 2 (A) which shows the flow of the exhaust in a comparative example, (B) is equivalent to FIG. 2 (A) which shows the flow of the exhaust in 1st Embodiment of this invention. It is explanatory drawing.

(First embodiment)
Hereinafter, the turbine 10 and the turbocharger 11 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4 and FIG. 6.

  As shown in FIG. 1, the turbine 10 constituting the turbocharger 11 includes a turbine rotor 12 and a turbine housing 14 provided so as to surround the outer periphery of the turbine rotor 12. The turbine rotor 12 includes a rotor shaft 16 and a turbine wheel 18 attached to one axial side of the rotor shaft 16 (hereinafter referred to as a turbine side or a shroud side).

  The rotor shaft 16 is rotatably supported by the housing 19, and a compressor wheel (not shown) is attached to the other side in the axial direction (hereinafter referred to as the compressor side or the hub side). Further, the turbine wheel 18 has a plurality of blades 20 extending radially, and a blade-to-blade channel 22 is formed by the plurality of blades 20.

  The turbine housing 14 includes a turbine chamber 24, a primary scroll 26, a secondary scroll 28, a primary nozzle 30, and a secondary nozzle 32. The turbine rotor 12 is accommodated in the turbine chamber 24. The turbine chamber inlet 24A is opened on the upstream side (the upper side and the lower side in FIG. 1) of the turbine chamber 24, and the turbine side (the left side in FIG. 1) on the downstream side. ) Has an opening 24B in the turbine chamber.

  The primary scroll 26 and the secondary scroll 28 are formed on the radially outer side of the turbine chamber 24, and are arranged in parallel with each other in the axial direction of the rotor shaft 16. The primary scroll 26 is on the shroud side (turbine side), the secondary scroll 28 is on the hub side (compressor side), and the flow volume of the secondary scroll 28 is larger than the flow volume of the primary scroll 26.

  The primary scroll 26 and the secondary scroll 28 extend in a spiral shape, and one end side (inlet side) communicates with the exhaust passage 34 of the internal combustion engine. A flow rate adjustment valve 36 that is controlled to be opened and closed between a fully open state and a fully closed state by the control device S is provided at a connection portion between the secondary scroll 28 and the exhaust passage 34.

  On the other end side (outlet side) of the primary scroll 26 and the secondary scroll 28, a primary nozzle 30 and a secondary nozzle 32 are provided to communicate the primary scroll 26 and the secondary scroll 28 with the turbine chamber inlet 24A, respectively. .

  As shown in FIG. 2A, the primary nozzle 30 includes a plurality (12 in this embodiment) of primary nozzle vanes 38. The primary nozzle vanes 38 adjust the flow rate of the exhaust gas flowing out from the primary scroll 26 to the turbine chamber 24, are arranged at equal intervals along the circumferential direction of the primary nozzle 30, and are fixed to the wall surface of the primary nozzle 30. .

  The secondary nozzle 32 has the same configuration as that of the primary nozzle 30 and includes a plurality (12 in this embodiment) of secondary nozzle vanes 40 as shown in FIG. The secondary nozzle vanes 40 are arranged at equal intervals along the circumferential direction of the secondary nozzle 32, and are fixed to the wall surface of the secondary nozzle 32.

  In addition, as for the primary nozzle vane 38 and the secondary nozzle vane 40, the outer peripheral shape (center line) in the exit end part 30B side of the primary nozzle 30 and the exit end part 32B side of the secondary nozzle 32 is made into the curve shape along a logarithmic spiral. ing. The logarithmic spiral is a kind of spiral that is often found in nature, and is a spiral drawn when a fluid flows in a spiral shape.

  Specifically, as shown in FIG. 2C, of the outer circumferences of the primary nozzle vane 38 and the secondary nozzle vane 40, about the inlet end 30A side of the primary nozzle 30 and the inlet end 32A side of the secondary nozzle 32. The range of 65% is a portion where the center line P extends substantially linearly. Then, the remaining range of about 35% to the outlet end 30B of the primary nozzle 30 and the outlet end 32B of the secondary nozzle 32 is a portion where the center line P is curved along the curvature of the logarithmic spiral. ing.

  As shown in FIGS. 1 and 3, the outlet end 30 </ b> B of the primary nozzle 30 and the outlet end 32 </ b> B of the secondary nozzle 32 are substantially at the same position in the radial direction of the rotor shaft 16 (vertical direction in FIG. 3). ing. Further, the ratio of the width L1 of the primary nozzle 30 (primary nozzle vane 38) and the width L2 of the secondary nozzle 32 (secondary nozzle vane 40) in the axial direction of the rotor shaft 16 (left-right direction in FIG. 3) is 2: 3. It is configured as follows.

  Further, the primary scroll 26 and the secondary scroll 28, and the primary nozzle 30 and the secondary nozzle 32 are separated from each other by a partition wall 42. The width L3 of the partition wall 42 in the axial direction of the rotor shaft 16 (left-right direction in FIG. 3) is configured to be in a range of 12% to 20% with respect to the width L4 of the turbine chamber inlet 24A.

  Further, in the radial direction of the rotor shaft 16 (vertical direction in FIG. 3), the inner end 42A of the partition wall 42 is radially inward (outside the outlet end 30B of the primary nozzle 30 and the outlet end 32B of the secondary nozzle 32). It is located on the lower side in FIG.

  Here, the inner end portion 42A of the partition wall 42 includes a shroud side end portion X at the outlet end portion 30B of the primary nozzle 30 and a hub side end portion Y at the outer peripheral portion 18A of the turbine wheel 18 (upper end portion in FIG. 3). It is located radially outward (upper side in FIG. 3) from the connected virtual line K.

  Specifically, when a line connecting the shroud side end Z in the inner end 42A of the partition wall 42 and the hub side end Y in the outer peripheral part 18A of the turbine wheel 18 is a virtual line R, the virtual line K The angle formed by the outer peripheral portion 18A of the turbine wheel 18 is about 40 degrees, and the angle formed by the phantom line R and the outer peripheral portion 18A of the turbine wheel 18 is about 45 degrees.

  Next, the operation of the turbine 10 and the turbocharger 11 in the first embodiment will be described.

  Since the flow rate of the exhaust gas flowing through the exhaust passage 34 is small when the internal combustion engine is rotating at a low speed, the flow rate adjusting valve 36 is fully closed by the control device S. At this time, the exhaust flowing through the exhaust passage 34 flows only into the primary scroll 26, passes through the primary nozzle 30, and flows into the turbine chamber 24.

  On the other hand, since the flow rate of the exhaust gas flowing through the exhaust passage 34 is large at the time of high rotation of the internal combustion engine, the flow rate adjustment valve 36 is fully opened by the control device S. At this time, the exhaust gas flowing through the exhaust passage 34 flows into the primary scroll 26 and the secondary scroll 28, passes through the primary nozzle 30 and the secondary nozzle 32, and flows into the turbine chamber 24.

  The exhaust gas flowing into the turbine chamber 24 flows into the inter-blade channel 22 of the turbine wheel 18 of the turbine rotor 12 housed in the turbine chamber 24. When exhaust flows through the inter-blade flow path 22, the turbine wheel 18 rotates, and the rotor shaft 16 to which the turbine wheel 18 is attached and the compressor wheel (not shown) attached to the rotor shaft 16 are simultaneously rotated. By rotating the compressor wheel, the air in the intake passage of the internal combustion engine is compressed and forcibly sent out toward the combustion chamber.

  Here, FIG. 4B shows an exhaust flow of the turbine 10 (turbocharger 11) of the present embodiment at the time of low rotation of the internal combustion engine. 4A shows a turbine 70 in which the inner end 80A of the partition wall 80 is located on the inner side in the radial direction of the rotor shaft 16 from the imaginary line K (lower side in FIG. 4A). .

  In the comparative example, when the internal combustion engine is running at a low speed, the exhaust gas that has passed through the primary nozzle 76 hits only a part of the turbine wheel 18 and flows back to the secondary nozzle 78 side by the centrifugal force of the turbine wheel 18. ing. For this reason, the flow rate of the exhaust gas to the turbine wheel 18 is reduced and the generated torque is reduced, so that the turbine efficiency is lowered.

  On the other hand, in the present embodiment, the exhaust gas that has passed through the primary nozzle 30 spreads throughout the turbine wheel 18. That is, the width of the turbine wheel 18 that receives the exhaust is widened, and a decrease in turbine efficiency is suppressed.

  As described above, according to the present embodiment, the inner end 42A of the partition wall 42 that separates the primary nozzle 30 and the secondary nozzle 32 is located radially inward of the rotor shaft 16 with respect to the outlet end 30B of the primary nozzle 30. ing. For this reason, when the internal combustion engine is running at a low speed, the backflow of the exhaust gas toward the secondary nozzle 32 is compared with the configuration in which the inner end 42A of the partition wall 42 is located at the same position as the outlet end 30B of the primary nozzle 30. Is suppressed.

  Furthermore, the inner end portion 42A of the partition wall 42 has a rotor shaft from a virtual line K connecting the shroud side end portion X at the outlet end portion 30B of the primary nozzle 30 and the hub side end portion Y at the outer peripheral portion 18A of the turbine wheel 18. 16 radially outside.

  For this reason, when the internal combustion engine is running at a low speed, the width of the rotor blade 20 of the turbine wheel 18 that receives the exhaust gas is smaller than the configuration in which the inner end portion 42A of the partition wall 42 is close to the outer peripheral portion 18A of the turbine wheel 18. spread. Therefore, the flow of exhaust gas from the primary nozzle 30 to the inter-blade channel 22 becomes smooth, and a decrease in turbine efficiency can be suppressed.

  Moreover, according to this embodiment, the primary nozzle 30 is arrange | positioned at the shroud side, and the secondary nozzle 32 is arrange | positioned at the hub side. For this reason, when the internal combustion engine is running at a low speed, the reverse flow rate of the exhaust gas to the secondary nozzle 32 is reduced as compared with the configuration in which the primary nozzle 30 is disposed on the hub side and the secondary nozzle 32 is disposed on the shroud side. To do. Therefore, a decrease in turbine efficiency can be suppressed.

  Further, according to the present embodiment, the outer peripheral shape of the outlet side of the primary nozzle 30 and the secondary nozzle 32 of the primary nozzle vane 38 and the secondary nozzle vane 40 is a curved shape along a logarithmic spiral. For this reason, the flow of the exhaust gas from the primary nozzle 30 and the secondary nozzle 32 to the inter-blade channel 22 becomes smooth.

  Specifically, as shown in FIG. 6A as a comparative example, the outer peripheral shape of the nozzle vane 44 is a shape that extends substantially linearly from the inlet end 46A of the nozzle 46 to the outlet end 46B. Since the exhaust gas that joins at the tip of the nozzle vane 44 (the outlet end portion 46B of the nozzle 46) collides, the flow rate of the exhaust gas becomes slow.

  On the other hand, as shown in FIG. 6B, the outer peripheral shape of the primary nozzle vane 38 is curved along the curvature of the logarithmic spiral on the outlet end 30B side of the primary nozzle 30. For this reason, the exhaust gas that joins at the tip of the primary nozzle vane 38 (the outlet end portion 30B of the primary nozzle 30) does not collide, and a decrease in the flow rate of the exhaust gas is suppressed and the pressure loss is reduced.

  Further, since the exhaust gas smoothly merges at the tip of the primary nozzle vane 38, the reverse flow rate of the exhaust gas to the secondary nozzle 32 side is reduced, and a decrease in turbine efficiency can be suppressed. Note that the secondary nozzle vane 40 has the same action as the primary nozzle vane 38.

(Second Embodiment)
Next, a turbine 50 and a turbocharger 51 according to a second embodiment of the present invention will be described with reference to FIG. Since the entire configuration is the same as that of the turbine 10 and the turbocharger 11 of the first embodiment, the same reference numerals are given and the description will be omitted as appropriate.

  In the turbine 50 constituting the turbocharger 51 in the second embodiment, as shown in FIG. 5B, the primary nozzle 52 is disposed on the hub side, and the secondary nozzle 54 is disposed on the shroud side.

  Further, the inner end portion 56A of the partition wall 56 includes a hub side end portion D at the outlet end portion 52A of the primary nozzle 52 and a shroud side end portion E at the outer peripheral portion 18A of the turbine wheel 18 (upper end portion in FIG. 5B). Is located radially outward (upper side in FIG. 5B) from the imaginary line M.

  Here, as a comparative example in FIG. 5A, a turbine 72 in which the inner end 62A of the partition wall 62 is located radially inward of the rotor shaft 16 from the imaginary line M (lower side in FIG. 5A). Show.

  In the comparative example, when the internal combustion engine is running at a low speed, the exhaust gas that has passed through the primary nozzle 58 hits only a part of the turbine wheel 18 and flows back to the secondary nozzle 60 side due to the centrifugal force of the turbine wheel 18. ing. For this reason, the flow rate of the exhaust gas to the turbine wheel 18 is reduced and the generated torque is reduced, so that the turbine efficiency is lowered.

  On the other hand, in the second embodiment, the exhaust gas that has passed through the primary nozzle 52 spreads throughout the turbine wheel 18. That is, the width of the turbine wheel 18 that receives the exhaust is widened, and a decrease in turbine efficiency is suppressed.

(Other embodiments)
Although the first and second embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. The first and second embodiments can be used in appropriate combination.

  For example, in the above embodiment, the primary nozzle vanes 38 and the secondary nozzle vanes 40 are provided for the primary nozzles 30 and 52 and the secondary nozzles 32 and 54, respectively. However, the secondary nozzle vanes 40 are provided for the secondary nozzles 32 and 54. It does not have to be done. The inner end portions 42A and 56A of the partition walls 42 and 56 may be provided with a taper. Furthermore, the primary nozzles 30 and 52 and the secondary nozzles 32 and 54 have substantially the same radial position, but the secondary nozzles 32 and 54 may be radially outward from the primary nozzles 30 and 52. Good.

10, 50 Turbine 11, 51 Turbocharger 12 Turbine rotor 14 Turbine housing 16 Rotor shaft 18 Turbine wheel 18A Outer peripheral part 20 Rotor blade 22 Interblade flow path 30, 52 Primary nozzle 30B, 52A Outlet end part 32, 54 Secondary nozzle 38 Primary nozzle vane (nozzle vane)
40 Secondary nozzle vane (nozzle vane)
42, 56 Bulkhead 42A, 56A Inner edge

Claims (4)

A turbine rotor comprising: a rotor shaft; and a turbine wheel having a plurality of blades forming an inter-blade flow path and provided on one axial side of the rotor shaft;
A turbine housing provided around the turbine wheel and into which the exhaust of the internal combustion engine is sent;
A primary nozzle that is provided in the turbine housing and causes the exhaust in the turbine housing to flow out to the inter-blade flow path;
A secondary nozzle that is provided in the turbine housing and selectively discharges exhaust gas in the turbine housing to the inter-blade flow path according to the rotational speed of the internal combustion engine;
A partition provided in the turbine housing and separating the primary nozzle and the secondary nozzle;
With
The inner end portion of the partition wall in the radial direction of the rotor shaft is located on the radially inner side from the outlet end portion of the primary nozzle, and one axial direction side of the rotor shaft at the outlet end portion of the primary nozzle A line connecting the shroud side end portion and the hub side end portion which is the other axial side of the rotor shaft in the outer peripheral portion of the turbine wheel, or the hub side at the outlet end portion of the primary nozzle. A turbine positioned on the radially outer side from a line connecting an end portion and an end portion on the shroud side in the outer peripheral portion of the turbine wheel.   The primary nozzle and the secondary nozzle are arranged in parallel along the axial direction of the rotor shaft, and the primary nozzle is on the shroud side and the secondary nozzle is on the hub side. The turbine described. The primary nozzle and the secondary nozzle include a plurality of nozzle vanes, and the outer peripheral shape of the outlet side of the primary nozzle and the secondary nozzle of the nozzle vane is a curved shape along a logarithmic spiral.
The turbine according to claim 1 or 2.   A turbocharger comprising the turbine according to claim 1.

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