JP2020051395A - Exhaust turbocharger structure - Google Patents

Abstract

To provide a water-cool exhaust turbocharger in which various parts of a turbine housing may be appropriately cooled.SOLUTION: An exhaust turbocharger has a configuration that: water jackets 16 allowing cooling water to flow therethrough are formed outside of a partition wall 131 surrounding a scroll passage 13 provided on the outer periphery of a turbine wheel 4 of the exhaust turbocharger, and the partition walls 141 and 151 surrounding an exhaust path 14 guiding exhaust gas discharged from the turbine wheel 4 in the axial direction or a waste gate flow path 15 for discharging excess exhaust gas; and both outer surfaces facing the water jackets 16 of the partition walls 131, 141 and 151 are arranged at a right angle or an obtuse angle.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a structure of an exhaust turbocharger attached to an internal combustion engine.

  The turbine wheel (or impeller) is rotated using the energy of the exhaust gas discharged from the cylinder of the internal combustion engine, and the rotation is transmitted to the compressor wheel (impeller) to compress and compress the intake air (supercharging). An exhaust turbocharger that feeds a cylinder to a cylinder is well known.

  The turbine housing accommodating the turbine wheel is exposed to high-temperature exhaust gas and has a high temperature. For this reason, a water cooling method of cooling the cooling water using cooling water is often used (for example, see the following Patent Document).

Japanese Utility Model Publication No. 63-022346

  As illustrated in FIG. 3, in a turbine housing of an existing exhaust turbocharger, a sectional shape of a partition wall B <b> 1 surrounding a scroll flow path B provided so as to surround an outer periphery of a turbine wheel A is orthogonal to an axial direction. It has a triangular shape that expands toward the outside in the radial direction.

  A water jacket C, through which cooling water flows, is provided on the outer side. A partition D1 surrounding an exhaust passage D for guiding exhaust gas discharged from the radial turbine A, and a partition B1 surrounding a scroll passage B are provided. At an acute angle when viewed from the water jacket C side, and the flow of the cooling water stagnates at a portion X at the corner between the partition walls B1 and D1. As a result, there is a concern that a member facing the site X, for example, the shroud piece E may be excessively heated.

  SUMMARY OF THE INVENTION An object of the present invention, which has been made in view of the above problems, is to enable appropriate cooling of various parts of a turbine housing of a water-cooled exhaust turbocharger.

  According to the present invention, a partition surrounding a scroll flow path provided on the outer periphery of a turbine wheel of an exhaust turbocharger, and a discharge path for guiding exhaust gas discharged in the axial direction by the turbine wheel or discharging excess exhaust gas A water jacket for circulating cooling water is formed outside the partition surrounding the waste gate flow path, and the outer surface of the partition facing the water jacket has an angle of right angle or obtuse. The structure of the machine was configured.

  ADVANTAGE OF THE INVENTION According to this invention, each part of the turbine housing of a water-cooled type exhaust turbocharger can be cooled appropriately.

FIG. 1 is a cross-sectional view illustrating an entire exhaust turbocharger according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a main part of the exhaust turbocharger of the same embodiment. FIG. 4 is an enlarged cross-sectional view illustrating a main part of a conventional exhaust turbocharger.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the overall structure of an exhaust turbocharger according to the present embodiment. The exhaust turbocharger of the present embodiment is a water-cooled turbocharger in which a housing (or a casing) is made of an aluminum alloy.

  The housing includes a bearing housing (center housing) 2, a turbine housing 1, and a compressor housing 3. In this embodiment, the bearing housing 2 and the compressor housing 3 are separate members, but the bearing housing 2 and the turbine housing 1 are integrally formed.

  A bearing 21 having a bearing hole 22 is formed in the bearing housing 2. For example, a semi-floating bearing 7 is provided in the bearing hole 22, and a turbine wheel (or an impeller) 4 and a compressor wheel (impeller) 5 are connected. A shaft 6 serving as a rotating shaft to be connected is rotatably supported. The turbine wheel 4 is accommodated in the turbine housing 1, and the compressor wheel 5 is accommodated in the compressor housing 3.

  An intake port 31 is opened in the compressor housing 3. In addition, the bearing housing 2 and the compressor housing 3 are fastened to form a diffuser flow path 32 therebetween. The diffuser passage 32 pressurizes the air taken in from the intake port 31. The diffuser flow path 32 has an annular shape from the inside in the radial direction perpendicular to the axial direction of the shaft 6 toward the outside, and the inside end thereof communicates with the intake port 31 via the compressor wheel 5.

  In addition, a compressor scroll passage 33 is provided in the compressor housing 3. The compressor scroll flow path 33 is formed radially outside the diffuser flow path 32 and has an annular shape. The compressor scroll passage 33 communicates with the diffuser passage 32 and an intake passage that is connected to a cylinder of the internal combustion engine.

  When the compressor wheel 5 rotates, air is sucked from the intake port 31 into the compressor housing 3. The speed of the air is increased by the action of centrifugal force in the process of flowing between the blades of the compressor wheel 5. The speed-up air is pressurized in the diffuser flow path 32 and the compressor scroll flow path 33 and guided to the intake passage of the internal combustion engine.

  An exhaust port 11 is open in the turbine housing 1. Further, an exhaust passage 12 and a turbine scroll passage 13 are formed in the turbine housing 1. The turbine scroll flow path 13 is formed radially outside the exhaust flow path 12 and has an annular shape. The turbine scroll passage 13 communicates with the exhaust passage 12 and an exhaust passage connected to a cylinder of the internal combustion engine.

  The exhaust gas discharged from the cylinder of the internal combustion engine and guided to the turbine scroll passage 13 reaches the exhaust port 11 via the exhaust passage 12 and the turbine wheel 4. The exhaust gas rotates the turbine wheel 4 in the process of flowing between the blades of the turbine wheel 4. The torque of the turbine wheel 4 is transmitted to the shaft 6 and the compressor wheel 5 to rotate them. As a result, the intake air is boosted by the rotational force of the compressor wheel 5, and is supplied to the cylinder of the internal combustion engine as supercharged air.

  It is customary to attach a waste gate to the exhaust turbocharger. The wastegate opens and closes a bypass connecting the upstream side and the downstream side of the turbine 4 in a path through which the exhaust gas flows. The wastegate detours a part of the exhaust gas so as not to flow into the turbine 4 and heads toward a cylinder of the internal combustion engine. It plays a role in suppressing the supercharging pressure from becoming excessively large.

  The waste gate valve 19 is a swing valve that is located at the end of the flow path 15 through which the exhaust gas that is going to bypass the turbine 4 flows, and that opens and closes the flow path 15. That is, the valve body 191 is supported on the distal end side of the arm 192 extending from the base end side to the hinge pin 193 and apart from the hinge pin 193, and the arm 192 and the valve body 191 rotate about the hinge pin 193. It is. The waste gate passage 15 is adjacent to the discharge passage 14 that guides the exhaust gas discharged from the radial turbine 4 toward the exhaust port. The direction in which the surplus exhaust gas is discharged along the waste gate passage 15 is substantially parallel to the axial direction.

  FIG. 2 shows a turbine housing 2 of an exhaust turbocharger and a structure for cooling the turbine housing 2 in the present embodiment. As described above, in the exhaust turbocharger of the present embodiment, the housing 1 is cooled by the cooling water. For that purpose, the partition 131 surrounding the turbine scroll flow path 13 on the outer periphery of the turbine wheel 4, the partition 141 surrounding the discharge path 14 for guiding the exhaust gas discharged from the turbine wheel 4 in the axial direction, and the waste gate are passed. A water jacket 16 for flowing cooling water is formed outside the partition 151 surrounding the waste gate channel 15 for guiding outside air gas. The water jacket 16 surrounds the flow paths 13, 14, and 15 around the axis.

  The cooling water that has flowed in from the inlet 17 into which the cooling water flows flows is diverted to both sides in the axial direction by the partition wall 18. One of the flows mainly cools the partition wall 131 surrounding the turbine scroll flow path 13. The other flow mainly cools the partition walls 141 and 151 surrounding the discharge path 14 and the wastegate flow path 15.

  In addition, in this embodiment, the angle formed between the outer surface of the partition 131 surrounding the turbine scroll flow path 13 facing the water jacket 16 and the outer surface of the partition 141 surrounding the discharge path 14 facing the water jacket 16 is formed. , Right angle or obtuse angle. In addition, the corners where the outer surfaces of both partition walls 131 and 141 intersect are chamfered or rounded. Thereby, the stagnation of the flow of the cooling water flowing through the portion is reduced.

  Further, the angle formed between the outer surface of the partition 131 surrounding the turbine scroll passage 13 facing the water jacket 16 and the outer surface of the partition 151 surrounding the wastegate passage 15 facing the water jacket 16 is a right angle or an obtuse angle. Is set to In addition, the corners where the outer surfaces of both partition walls 131 and 151 meet are chamfered or rounded. Thereby, the stagnation of the flow of the cooling water flowing through the portion is reduced.

  In this embodiment, the partition surrounding the scroll flow path 13 provided on the outer periphery of the turbine wheel 4 of the exhaust turbocharger, and the discharge path 14 or the excess path 14 for guiding the exhaust gas discharged from the turbine wheel 4 in the axial direction. A water jacket 16 for circulating cooling water is formed outside the partition 151 surrounding the waste gate flow path 15 for discharging the exhaust gas. The outer surfaces of the partition 131, 141, 151 facing the water jacket 16 are formed. The structure of the exhaust turbocharger is formed at an angle of right or obtuse.

  According to the present embodiment, each part of the turbine housing 2 of the water-cooled exhaust turbocharger can be appropriately cooled. Therefore, the concern that the temperature of the shroud piece 8 or the like rises excessively and exceeds the heat resistance limit is eliminated.

  Note that the present invention is not limited to the embodiment described in detail above. The specific configuration of each part can be variously modified without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an exhaust turbocharger of an internal combustion engine mounted on a vehicle or the like.

DESCRIPTION OF SYMBOLS 1 ... Turbine housing 13 ... Turbine scroll flow path 131 ... Partition wall 14 ... Discharge path 141 ... Partition wall 15 ... Waste gate flow path 151 ... Partition wall 16 ... Water jacket

Claims (1)

A partition wall surrounding a scroll flow path provided on an outer periphery of a turbine wheel of the exhaust turbocharger, and a discharge path for guiding exhaust gas discharged from the turbine wheel in an axial direction or a waste gate flow for discharging surplus exhaust gas. A structure of an exhaust turbocharger in which a water jacket for circulating cooling water is formed outside a partition surrounding a road, and an angle between an outer surface of the partition facing the water jacket is a right angle or an obtuse angle.

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