Turbine housing, turbocharger and gasoline engine

Abstract

The exhaust gas duct is connected to the exhaust gas discharge port by the exhaust gas discharge port, and the exhaust gas discharge port is connected to the exhaust gas discharge port by the exhaust gas discharge port.

Description

Technical Field

[0001] The present disclosure relates to a turbine housing, a turbocharger including the turbine housing, and a gasoline engine including the turbocharger. Background Art

[0002] Engines used in automobiles and other applications are sometimes equipped with turbochargers to improve engine output and fuel efficiency. Turbochargers utilize the energy of high-temperature fluids, such as exhaust gas, to rotate turbine blades, which in turn rotate the compressor's impeller, which is mechanically connected to the turbine blades via a rotating shaft. The turbocharger's rotating impeller compresses gas (e.g., air) used for combustion in the engine and delivers it to the engine.

[0003] Patent Document 1 discloses a turbocharger comprising a turbine housing having an internally formed wastegate passage (bypass flow path) that bypasses a portion of the exhaust gas without directing it toward the turbine blades, and a wastegate valve that opens and closes the wastegate passage. Patent Document 2 also discloses an exhaust gas purification catalyst installed in the exhaust system of an engine (internal combustion engine). The exhaust gas purification catalyst has the function of purifying harmful components contained in the exhaust gas, such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx), and capturing particulate matter (PM) contained in the exhaust gas.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5846351

[0007] Patent Document 2: Japanese Patent No. 6487982 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, the performance of the exhaust gas purification catalyst is affected by the catalyst's temperature or oxygen concentration. Therefore, exhaust gas passing through the exhaust gas bypass passage, i.e., exhaust gas whose energy has been recovered by the turbine blades but whose temperature has not been lowered, is sometimes sent to the exhaust gas purification catalyst located downstream of the exhaust gas bypass passage to heat the exhaust gas purification catalyst and activate it. If the heat dissipation loss in the turbine housing caused by the exhaust gas passing through the exhaust gas bypass passage is large, the temperature of the exhaust gas purification catalyst may not be effectively increased. In particular, in the case of a gasoline engine, the exhaust gas discharged from the engine is at a higher temperature than that of a diesel engine, etc., and the temperature difference between the exhaust gas and the turbine housing increases, thereby potentially increasing the heat dissipation loss in the turbine housing. Therefore, it is necessary to suppress the heat dissipation loss in the turbine housing caused by the exhaust gas passing through the exhaust gas bypass passage.

[0010] In view of the above situation, an object of at least one embodiment of the present disclosure is to provide a turbine housing, a turbocharger and a gasoline engine that can suppress the heat dissipation loss of exhaust gas passing through the exhaust gas bypass passage in the turbine housing and can effectively increase the temperature of the exhaust gas purification catalyst arranged on the downstream side of the turbine housing.

[0011] Technical solutions to solve problems

[0012] One embodiment of the present disclosure provides a turbine housing,

[0013] It is configured to house turbine blades driven by exhaust gas discharged from a gasoline engine, and comprises a main body and an inlet flange.

[0014] The main body portion has a vortex flow path wall surface inside thereof, which forms a vortex flow path formed in a vortex shape for guiding the exhaust gas toward the turbine blades;

[0015] an exhaust gas discharge path wall surface forming an exhaust gas discharge path for discharging the exhaust gas having passed through the turbine blades; and

[0016] an exhaust gas bypass passage wall surface forming an exhaust gas bypass passage that bypasses the turbine blades and connects the vortex flow passage and the exhaust gas discharge passage;

[0017] The inlet flange portion is provided at the upstream end of the vortex flow path of the main body portion and is formed with an exhaust gas inlet connected to the vortex flow path.

[0018] An inlet-side opening edge of the exhaust gas bypass passage formed on the swirl flow path wall surface is provided at a position where at least a portion of the inlet-side opening edge is visible from outside the turbine housing through the exhaust gas inlet port.

[0019] One embodiment of the present disclosure provides a turbocharger including the turbine housing.

[0020] One embodiment of the present disclosure provides a gasoline engine comprising:

[0021] a cylinder block having a plurality of cylinders;

[0022] an exhaust manifold for merging exhaust gases discharged from the plurality of cylinders, wherein at least a portion of the exhaust manifold is disposed inside the cylinder block;

[0023] The turbocharger,

[0024] The inlet flange portion of the turbine housing is connected to the exhaust manifold.

[0025] Effects of the Invention

[0026] According to at least one embodiment of the present disclosure, a turbine housing, a turbocharger, and a gasoline engine are provided that can suppress heat dissipation loss of exhaust gas passing through an exhaust bypass passage in the turbine housing and effectively increase the temperature of an exhaust gas purification catalyst arranged on the downstream side of the turbine housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic configuration diagram schematically showing the configuration of an engine including a turbocharger according to an embodiment of the present disclosure.

[0028] Figure 2 This is a schematic cross-sectional view taken along the axis of a turbine housing according to one embodiment of the present disclosure.

[0029] Figure 3 This is an explanatory diagram for explaining a turbine housing according to an embodiment of the present disclosure.

[0030] Figure 4 This is an explanatory diagram for explaining an inlet-side opening edge of an exhaust gas bypass passage of a turbine housing according to one embodiment of the present disclosure.

[0031] Figure 5 This is an explanatory diagram for explaining the thermal expansion of the turbine housing according to one embodiment of the present disclosure.

[0032] Figure 6 This is an explanatory diagram for explaining an inlet-side opening edge of an exhaust gas bypass passage of a turbine housing according to one embodiment of the present disclosure.

[0033] Figure 7 This is an explanatory diagram for explaining an inlet-side opening edge of an exhaust gas bypass passage of a turbine housing according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] Several embodiments of the present disclosure are described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure and are merely illustrative examples.

[0035] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only strictly indicate such configurations, but also indicate a state of relative displacement of angles or distances with a tolerance or a degree to obtain the same function.

[0036] For example, expressions such as “same,” “equal,” and “homogeneous” indicating a state in which things are equal not only indicate a strictly equal state but also indicate a state in which there is a tolerance or a difference in the degree to which the same function is achieved.

[0037] For example, expressions indicating shapes such as a quadrilateral or a cylinder not only indicate shapes such as a quadrilateral or a cylinder in a strict geometric sense, but also indicate shapes including concave and convex portions or chamfered portions within a range that achieves the same effect.

[0038] On the other hand, the expression “having”, “including”, or “having” a constituent element is not an exclusive expression that excludes the presence of other constituent elements.

[0039] In addition, the same reference numerals are given to the same structures and the description thereof may be omitted.

[0040] (engine)

[0041] Figure 1 This is a schematic configuration diagram schematically showing the configuration of an engine including a turbocharger according to an embodiment of the present disclosure.

[0042] like Figure 1 As shown in FIG. 1 , several embodiments of the turbocharger 2 are mounted on the gasoline engine 1. Figure 1 As shown, the gasoline engine 1 includes at least a cylinder block 11 having a plurality of cylinders 12 , an exhaust manifold 13 for merging exhaust gases discharged from the plurality of cylinders 12 , and the turbocharger 2 .

[0043] In the illustrated embodiment, the gasoline engine 1 further includes a compressed gas supply line 14 for guiding compressed gas compressed by the turbocharger 2 to each of the plurality of cylinders 12, a cooler 15 provided in the compressed gas supply line 14, a water jacket 16 provided inside the cylinder block 11, and a refrigerant supply line 17 for supplying refrigerant to the water jacket 16 from outside the cylinder block 11. The cooler 15 is configured to cool the compressed gas flowing in the compressed gas supply line 14. The water jacket 16 includes a flow path provided around each of the plurality of cylinders 12 to allow refrigerant to flow. The refrigerant supply line 17 is configured to supply refrigerant to the water jacket 16. The compressed gas includes compressed air. The refrigerant includes cooling water.

[0044] exist Figure 1In the illustrated embodiment, the refrigerant supply line 17 includes a cooling water storage tank 171 configured to store cooling water, a cooling water supply pipe 172 for conveying the cooling water stored in the cooling water storage tank 171 to the water jacket 16, and a cooling water pump 173 provided in the cooling water supply pipe 172. The cooling water supply pipe 172 is connected to the cooling water storage tank 171 on one side and to the water jacket 16 on the other side. The cooling water pump 173 is configured to convey cooling water to the other side of the cooling water supply pipe 172. By driving the cooling water pump 173, the cooling water stored in the cooling water storage tank 171 is conveyed to the cooling water supply pipe 172, flows through the cooling water supply pipe 172 toward the other side, and is then supplied to the water jacket 16. The cooling water (refrigerant) in the water jacket 16 cools the cylinders 12, the cylinder block 11, and the like.

[0045] (Turbocharger)

[0046] like Figure 1 As shown, the turbocharger 2 includes a turbine blade 3, a compressor blade 21, a rotating shaft 22 connected to the turbine blade 3 and the compressor blade 21, a turbine housing 4 configured to rotatably accommodate the turbine blade 3, and a compressor housing 23 configured to rotatably accommodate the compressor blade 21. In the illustrated embodiment, the turbocharger 2 further includes a bearing 24 that rotatably supports the rotating shaft 22 and a bearing housing 25 configured to accommodate the bearing 24.

[0047] In the illustrated embodiment, the rotating shaft 22 is connected to the turbine blades 3 on one longitudinal side and to the compressor blades 21 on the other longitudinal side. The rotating shaft 22 is rotatably supported by bearings 24 between the turbine blades 3 and the compressor blades 21 in the longitudinal direction. The turbine blades 3 and the compressor blades 21 are each rotatable integrally via the rotating shaft 22. A bearing housing 25 is disposed between the turbine housing 4 and the compressor housing 23 and mechanically connected to each of the turbine housing 4 and the compressor housing 23 via fastening members (not shown), such as bolts or V-clamps.

[0048] like Figure 1 As shown, the turbine housing 4 is formed with an exhaust gas inlet 41 for introducing exhaust gas into the interior and an exhaust gas outlet 42 for discharging the exhaust gas to the outside. The compressor housing 23 is formed with a gas inlet 231 for introducing gas into the interior and a gas outlet 232 for discharging the gas that has passed through the compressor blades 21 to the outside. The compressed gas supply line 14 is connected to the gas outlet 232 on one side and to each of the multiple cylinders 12 on the other side.

[0049] The turbocharger 2 directs exhaust gas discharged from the exhaust manifold 13 into the interior of the turbine housing 4 through the exhaust gas inlet 41. At least a portion of the exhaust gas directed into the turbine housing 4 is directed toward the turbine blades 3. The turbocharger 2 uses the energy of the exhaust gas directed toward the turbine blades 3 to rotate the turbine blades 3. The compressor blades 21 are connected to the turbine blades 3 via the rotating shaft 22 and rotate in conjunction with the rotation of the turbine blades 3. The turbocharger 2 is configured such that the rotation of the compressor blades 21 compresses the gas introduced into the compressor housing 23 through the gas inlet 231 and delivers the compressed gas to each of the multiple cylinders 12 through the gas outlet 232 and the compressed gas supply line 14. The compressed gas delivered to each of the multiple cylinders 12 is combusted with fuel to generate exhaust gas. Furthermore, the exhaust gas that has passed through the turbine blades 3 is discharged to the exterior of the turbine housing 4 through the exhaust gas outlet 42.

[0050] (Exhaust Gas Purification Catalyst)

[0051] In the illustrated embodiment, the gasoline engine 1 further includes an exhaust gas purification catalyst 18 disposed on the downstream side of the turbine housing 4. Exhaust gas discharged to the outside of the turbine housing 4 through the exhaust gas outlet 42 is fed to the exhaust gas purification catalyst 18. The exhaust gas purification catalyst 18 has the function of purifying harmful components such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) contained in the exhaust gas, or capturing particulate matter (PM) contained in the exhaust gas. The exhaust gas purification catalyst 18 may be any of the conventionally known three-way catalysts, oxidation catalysts (DOCs), or NOx adsorption reduction catalysts. The exhaust gas purification catalyst 18 may also include a carrier and a precious metal supported on the carrier. Here, the precious metal supported on the carrier may also include at least one of rhodium (Rh), palladium (Pd), or platinum (Pt). The exhaust gas purification catalyst 18 is heated by, for example, utilizing the heat of the exhaust gas, thereby activating the exhaust gas purification reaction.

[0052] (Turbine housing)

[0053] Figure 2 : is a schematic cross-sectional view along the axis of the turbine housing according to one embodiment of the present disclosure. Figure 2As shown, the turbine housing 4 includes a main body 5. The main body 5 internally comprises a vortex flow path wall surface 6 forming a vortex flow path 60 that guides the exhaust gas toward the turbine blades 3; an exhaust gas discharge path wall surface 7 forming an exhaust gas discharge path 70 for discharging the exhaust gas that has passed through the turbine blades 3; and an exhaust gas bypass path wall surface 8 forming an exhaust gas bypass path 80 that connects the vortex flow path 60 and the exhaust gas discharge path 70, bypassing the turbine blades 3. Hereinafter, the upstream side in the exhaust gas flow direction will sometimes be simply referred to as the upstream side, and the downstream side in the exhaust gas flow direction will sometimes be simply referred to as the downstream side. The exhaust gas inlet 41 is connected to the vortex flow path 60, and the exhaust gas outlet 42 is connected to the exhaust gas discharge path 70.

[0054] The turbine housing 4 accommodates the turbine blade 3 on the inner circumference of the vortex flow path 60. Hereinafter, the direction in which the axis LA of the turbine blade 3 extends is defined as the axial direction X, and the direction perpendicular to the axis LA is defined as the radial direction Y. The exhaust gas outlet 42 is located on the side of the turbine blade 3 in the axial direction X ( Figure 2 The right side in the middle is defined as the turbine side XF. In addition, the side opposite to the turbine side XF in the axial direction X, that is, the side where the turbine blade 3 is located relative to the exhaust gas outlet 42 ( Figure 2 The left side in the middle is defined as the compressor side XR.

[0055] (Turbine blades)

[0056] like Figure 2 As shown, the turbine blade 3 includes a hub 31 and a plurality of turbine blades 33 disposed on an outer surface 32 of the hub 31. Because the hub 31 is coupled to the longitudinal side of the rotating shaft 22, the hub 31 and the plurality of turbine blades 33 can rotate integrally with the rotating shaft 22 about the axis LA of the turbine blade 3. The hub 31 is formed into a concavely curved shape, with the outer surface 32 increasing in distance from the axis LA as it moves from the turbine side XF toward the compressor side XR. The plurality of turbine blades 33 are spaced apart from each other in the circumferential direction around the axis LA.

[0057] The turbine housing 4 has a shroud surface within it. This shroud surface includes a convexly curved surface 43, which is formed in a convexly curved shape, with the distance from the axis LA increasing as it moves from the turbine side XF toward the compressor side XR. A gap is formed between the convexly curved surface 43 and the respective tips 34 of the turbine blades 33. The shroud surface 44 is formed between the vortex flow path wall surface 6 and the exhaust gas discharge path wall surface 7. The downstream end 441 of the shroud surface 44 is connected to the vortex flow path wall surface 6, while the upstream end 442 of the shroud surface 44 is connected to the exhaust gas discharge path wall surface 7.

[0058] The turbine blades 3 are arranged between the vortex flow path 60 and the exhaust gas discharge path 70, and are configured to guide exhaust gas introduced from the outside in the radial direction Y through the vortex flow path 60 toward the turbine side XF in the axial direction X. The exhaust gas discharge path 70 is configured to guide exhaust gas that has passed through the turbine blades 3 from the compressor side XR toward the turbine side XF in the axial direction X. After passing through the turbine blades 3, the exhaust gas flows toward the turbine side XF in the exhaust gas discharge path 70 and is then discharged to the outside of the turbine housing 4 through the exhaust gas outlet 42.

[0059] The turbine housing 4 has an inlet-side opening edge 81 of the exhaust bypass passage 80 formed on the scroll flow path wall surface 6, and an outlet-side opening edge 82 of the exhaust bypass passage 80 formed on the exhaust gas exhaust path wall surface 7. The exhaust bypass passage wall surface 8 is connected to the scroll flow path wall surface 6 via the inlet-side opening edge 81, and is connected to the exhaust gas exhaust path wall surface 7 via the outlet-side opening edge 82. The exhaust bypass passage 80 has an inlet opening 810 formed inside the inlet-side opening edge 81, and an outlet opening 820 formed inside the outlet-side opening edge 82. The inlet opening 810 of the exhaust bypass passage 80 is connected to the scroll flow path 60, and the outlet opening 820 is connected to the exhaust gas exhaust path 70.

[0060] The turbocharger 2 further includes a wastegate valve 26 configured to open and close an outlet opening 820 of the wastegate passage 80. The wastegate valve 26 includes a valve body 261 that closes the outlet opening 820 and a valve body drive unit 262 that supports the valve body 261 and is configured to drive the valve body 261. The wastegate valve 26 controls the flow rate of exhaust gas flowing from the wastegate passage 80 to the exhaust gas discharge path 70 by driving the valve body 261 via the valve body drive unit 262 to close or open the outlet opening 820. Opening the outlet opening 820 in the wastegate valve 26 diverts a portion of the exhaust gas flowing in the vortex flow path 60 toward the turbine blades 3 to the wastegate passage 80. This reduces the amount and thermal energy of the exhaust gas delivered to the turbine blades 3, thereby reducing the boost pressure of the compressed gas delivered to each of the multiple cylinders 12.

[0061] exist Figure 2 The plane in which the axis LA of the turbine blade 3 and the center C1 of the outlet opening 820 are located is schematically shown. Figure 2As shown, the exhaust gas discharge passage wall surface 7 includes, along at least a portion of its circumference, an inclined surface 71 that is inclined so that the distance from the axis LA increases as it approaches the turbine side XF, and a valve accommodation surface 73 that extends from a downstream end 72 of the inclined surface 71 along the axial direction X toward the turbine side XF. The exhaust gas discharge passage 70 includes a valve accommodation space 70A that accommodates the valve body 261 of the wastegate valve 26. The valve accommodation space 70A is defined by the inclined surface 71 and the valve accommodation surface 73. An outlet-side opening edge 82 is formed on at least one of the inclined surface 71 and the valve accommodation surface 73, and the outlet opening 820 is connected to the valve accommodation space 70A.

[0062] Figure 3 This is an explanatory diagram for explaining a turbine housing according to one embodiment of the present disclosure. Figure 3 8 schematically shows the turbine housing 4 as viewed from above, as viewed from the outlet side (turbine side XF) of the exhaust gas discharge path 70 along the axis LA. Figure 3 As shown, the turbine housing 4 includes the above-mentioned main body portion 5 and the inlet flange portion 9 .

[0063] like Figure 3 As shown, the inlet flange portion 9 is provided at the upstream end 61 of the vortex flow path 60 of the main body 5 and includes a flange portion 91 protruding toward the outer peripheral side. The exhaust gas inlet 41 connected to the vortex flow path 60 is formed in the inlet flange portion 9. Figure 1 In the illustrated embodiment, the inlet flange portion 9 is connected to the exhaust manifold 13. Therefore, exhaust gas flows from the exhaust manifold 13 into the swirl flow path 60 through the exhaust gas inlet port 41. In the illustrated embodiment, the turbine housing 4 is formed into its shape by casting.

[0064] like Figure 3 As shown, the turbine housing 4 of several embodiments includes the aforementioned main body 5 and the aforementioned inlet flange 9. The main body 5 internally includes the aforementioned vortex flow path wall surface 6, the exhaust gas discharge path wall surface 7, and the exhaust gas bypass passage wall surface 8. The inlet flange 9 is formed with an exhaust gas inlet 41 connected to the vortex flow path 60. An inlet-side opening edge 81 of an exhaust gas bypass passage 80 formed on the vortex flow path wall surface 6 is positioned such that at least a portion of the inlet-side opening edge 81 is visible from the outside of the turbine housing 4 through the exhaust gas inlet 41.

[0065] In the illustrated embodiment, Figure 3 In the top view shown in FIG. 1 , the vortex flow path wall surface 6 includes a vortex outer wall surface 6A forming the outer peripheral side of the vortex flow path 60 and a vortex inner wall surface 6B formed on the inner peripheral side of the vortex outer wall surface 6A and forming the vortex flow path 60 between the vortex outer wall surface 6A. The vortex inner wall surface 6B forms the inner peripheral side of the vortex flow path 60. Figure 3In the top view shown, the tangent line TL passing through the upstream end 61A of the vortex outer wall surface 6A (the outer peripheral end of the exhaust gas inlet 41) and the vortex inner wall surface 6B is tangent to the vortex inner wall surface 6B at the point of tangency P1. The aforementioned inlet-side opening edge 81 is located upstream of the tangent point P1 on the vortex inner wall surface 6B. In this case, the inlet-side opening edge 81 is located at a position where at least a portion of the inlet-side opening edge 81 is visible from the outside of the turbine housing 4 through the exhaust gas inlet 41. Furthermore, even if the inlet-side opening edge 81 is not visible from the outside of the turbine housing 4 through the exhaust gas inlet 41, if the inlet-side opening edge 81 on the vortex inner wall surface 6B is visible from the outside of the turbine housing 4 through the exhaust gas inlet 41, the inlet-side opening edge 81 is located at a position visible from the outside of the turbine housing 4 through the exhaust gas inlet 41.

[0066] In the illustrated embodiment, Figure 3 As shown in the top view, with respect to the inlet side opening edge 81, at least a portion of the inlet side opening edge 81 is provided at a position closer to the upstream side (on the upstream end 61B side) than the length center position P3 of the curve connecting the upstream end 61B (the inner peripheral end of the exhaust gas inlet 41) in the vortex inner wall surface 6B and the tongue P2.

[0067] According to the above configuration, at least a portion of the inlet-side opening edge 81 of the exhaust gas bypass passage 80 of the turbine housing 4 is positioned at a position visible from outside the turbine housing 4 through the exhaust gas inlet port 41. In this case, the length of the vortex flow path 60 (upstream vortex flow path 60A) between the inlet opening 810 of the exhaust gas bypass passage 80 and the exhaust gas inlet port 41 of the inlet flange portion 9 is shortened. By shortening the length of the upstream vortex flow path 60A, it is possible to suppress heat loss in the upstream vortex flow path 60A caused by the exhaust gas passing through the exhaust gas bypass passage 80, that is, the exhaust gas flowing from the exhaust gas inlet port 41 through the upstream vortex flow path 60A into the exhaust gas bypass passage 80. This suppresses the temperature drop of the exhaust gas flowing downstream of the turbine housing 4 through the exhaust gas bypass passage 80, effectively increasing the temperature of the exhaust gas purification catalyst 18 disposed downstream of the turbine housing 4.

[0068] When the turbine housing 4 is mounted on the gasoline engine 1, the exhaust gas exhausted from the gasoline engine 1 becomes hotter than when the turbine housing 4 is mounted on another internal combustion engine such as a diesel engine. This increases the temperature difference between the exhaust gas and the turbine housing 4, and thus may increase heat dissipation losses in the turbine housing 4. With the above-described structure, even when the turbine housing 4 is mounted on the gasoline engine 1, heat dissipation losses in the turbine housing 4 caused by the exhaust gas passing through the exhaust gas bypass passage 80 can be effectively suppressed.

[0069] Furthermore, the following embodiments are also applicable to a case where the inlet-side opening edge 81 is not provided at a position visible from the outside of the turbine housing 4 through the exhaust gas inlet port 41 .

[0070] In several embodiments, in the presence of Figure 2 In the plane shown between the axis LA of the turbine blade 3 and the center C1 of the outlet opening 820, the exhaust gas discharge passage 70 is configured to guide exhaust gas from one side (the compressor side XR) to the other side (the turbine side XF) in the direction (axial direction X) in which the axis LA of the turbine blade 3 extends. A normal line N1 (a straight line passing through the center C1 and perpendicular to the outlet opening 820) passing through the center C1 of the exhaust gas bypass passage 80 is configured to extend in a direction intersecting the axis LA of the turbine blade 3.

[0071] In the illustrated embodiment, the vortex flow path 60 is formed in a spiral shape that spirals toward the compressor side XR in the axial direction X as it approaches the downstream side (the turbine blade 3 side). Therefore, the upstream portion of the vortex flow path 60 is located on the outer periphery of the exhaust gas discharge path 70. The exhaust gas bypass passage 80 extends radially and is inclined such that the center C1 of its outlet opening 820 is located closer to the turbine side XF than the center C2 of its inlet opening 810. The inlet opening 810 and the outlet opening 820 each open in a direction extending along the normal line N1.

[0072] According to the above configuration, the exhaust bypass passage 80 has its outlet opening 820 connected to the exhaust gas discharge passage 70, and its inlet opening 810 connected to the vortex flow path 60 provided on the outer periphery of the exhaust gas discharge passage 70. The exhaust bypass passage 80 is configured such that a normal line N1 passing through the center C1 of the outlet opening 820 extends in a direction intersecting the axis LA of the turbine blade 3. In this case, the length of the exhaust bypass passage 80 (the distance from the inlet opening 810 to the outlet opening 820) can be shortened compared to a case where the normal line N1 extends along the axis LA of the turbine blade 3. By shortening the length of the exhaust bypass passage 80, heat dissipation losses in the exhaust bypass passage 80 can be suppressed. This suppresses a decrease in the temperature of the exhaust gas flowing downstream of the turbine housing 4 through the exhaust bypass passage 80, effectively increasing the temperature of the exhaust purification catalyst 18 disposed downstream of the turbine housing 4.

[0073] In several embodiments, in the presence of Figure 2 On the plane of the axis LA of the turbine blade 3 shown and the center C1 of the outlet opening 820 , when the angle formed by the axis LA and the normal line N1 is θ, 30°≤θ≤60° is satisfied.

[0074] According to the above configuration, when the angle θ satisfies 30°≤θ≤60°, the length of the exhaust bypass passage 80 can be shortened. Furthermore, when the angle θ satisfies 30°≤θ≤60°, exhaust gas flowing into the exhaust gas discharge passage 70 from the outlet opening 820 of the exhaust bypass passage 80 can be guided by the exhaust gas discharge passage wall surface 7 toward the exhaust gas discharge port 42 and discharged from the exhaust gas discharge port 42 to the exterior of the turbine housing 4. In this case, the exhaust gas passing through the exhaust bypass passage 80 can flow smoothly within the exhaust gas discharge passage 70, thereby minimizing heat loss in the exhaust gas discharge passage 70 caused by the exhaust gas passing through the exhaust bypass passage 80. This also minimizes temperature drops in the exhaust gas flowing downstream of the turbine housing 4 through the exhaust bypass passage 80, effectively increasing the temperature of the exhaust gas purification catalyst 18 disposed downstream of the turbine housing 4.

[0075] like Figure 1 As shown, the turbocharger 2 of several embodiments includes the above-described turbine housing 4. In this case, the turbocharger 2 has a short upstream vortex flow path 60A of the turbine housing 4. This reduces heat dissipation losses in the upstream vortex flow path 60A of the exhaust gas passing through the exhaust bypass passage 80, thereby effectively increasing the temperature of the exhaust gas purification catalyst 18 disposed downstream of the turbine housing 4.

[0076] like Figure 1 As shown, the gasoline engine 1 according to several embodiments includes the aforementioned turbocharger 2, the aforementioned cylinder block 11 having a plurality of cylinders 12, and the aforementioned exhaust manifold 13 for merging exhaust gases discharged from the plurality of cylinders 12. At least a portion of the exhaust manifold 13 is disposed within the cylinder block 11. The exhaust manifold 13 is connected to the inlet flange portion 9 of the aforementioned turbine housing 4.

[0077] According to the above configuration, exhaust gas discharged from each of the multiple cylinders 12 passes through the exhaust manifold 13 and then flows into the swirl flow path 60 from the exhaust gas inlet 41 of the inlet flange portion 9. At least a portion of the exhaust manifold 13 is disposed within the cylinder block 11 having the multiple cylinders 12, and the inlet flange portion 9 is connected to the exhaust manifold 13. In this configuration, heat dissipation losses in the exhaust gas discharged from each of the multiple cylinders 12 in the exhaust manifold 13 can be suppressed. By suppressing the temperature drop on the upstream side of the exhaust gas flowing toward the downstream side of the turbine housing 4 through the exhaust gas bypass passage 80, the temperature of the exhaust gas purification catalyst 18 disposed downstream of the turbine housing 4 can be effectively increased.

[0078] Figure 4 This is an explanatory diagram for explaining the opening edge on the inlet side of the exhaust gas bypass passage of the turbine housing according to one embodiment of the present disclosure. Figure 4, the turbine housing 4 is schematically shown when viewed from the front, that is, along the normal line N2 (a straight line passing through the center C2 and perpendicular to the inlet opening 810) passing through the center C2 of the inlet opening 810 of the exhaust gas bypass passage 80, and the inlet side opening edge 81 of the vortex flow path 60 is identified. In some embodiments, as Figure 4 As shown, the inlet side opening edge 81 is formed into a circular ring shape when viewed from the front. In addition, in other embodiments, the inlet side opening edge 81 can be formed into an elliptical ring shape when viewed from the front, or can be formed into a rectangular ring shape when viewed from the front.

[0079] Hereinafter, when the inlet opening edge 81 is viewed from above along the normal line N2 , a direction perpendicular to the straight line LC connecting the upstream end 841 and the downstream end 831 of the inlet opening edge 81 is defined as the opening width direction W of the inlet opening 810 of the wastegate passage 80 .

[0080] like Figure 4 As shown, the inlet side opening edge 81 includes: a downstream end portion 83, which includes the downstream end 831 of the inlet side opening edge 81; an upstream end portion 84, which includes the upstream end 841 of the inlet side opening edge 81; a one side end portion 85, which includes one end 851 of the opening width direction W of the inlet side opening edge 81; and the other side end portion 86, which includes the other end 861 of the opening width direction W of the inlet side opening edge 81.

[0081] In recent years, the temperature of the exhaust gas introduced into the turbine housing 4 has tended to rise to high temperatures (e.g., 1000°C or higher) in order to achieve higher output in gasoline engines 1. As described above, if the length of the vortex flow path 60 (upstream vortex flow path 60A) between the inlet opening 810 of the exhaust gas bypass passage 80 and the exhaust gas inlet port 41 of the inlet flange portion 9 is shortened, the inlet-side opening edge 81 is exposed to the exhaust gas at a higher temperature than before.

[0082] Figure 5 This is an explanatory diagram for explaining the thermal expansion of the turbine housing according to one embodiment of the present disclosure. Figure 5 9 shows the analysis results of the thermal strain of the turbine housing 4 described above, and a portion with a larger thermal strain is displayed more densely.

[0083] like Figure 4 As shown, the inlet side opening edge 81 is heated by the exhaust gas flowing in the vortex flow path 60 on the downstream side (the side away from the exhaust gas inlet 41 in the extending direction of the axis LB of the exhaust gas inlet 41, Figure 4 The end portion (downstream end portion 83) of the upper middle portion generates a gap along the opening width direction W ( Figure 4Since the inlet flange 9 is connected to the exhaust manifold 13, it is cooled by the cooling water (refrigerant) in the water jacket 16. Therefore, the upstream side of the inlet side opening edge 81 (the side close to the exhaust gas inlet 41 in the extending direction of the axis LB) is Figure 4 The end portion (upstream end portion 84) of the inlet side opening edge 81 has a thermal expansion in the opening width direction W that is suppressed compared to the downstream end portion 83. Due to the difference in thermal expansion between the upstream end portion 84 and the downstream end portion 83 of the inlet side opening edge 81, Figure 5 The thermal strain increases near both ends of the opening width direction W, namely near one end 85 or the other end 86, and may cause cracks. It is necessary to prevent these cracks from progressing and penetrating the turbine housing 4, causing exhaust gas to leak outside the turbine housing 4.

[0084] Figure 6 and Figure 7 Each of them is an explanatory diagram for explaining the opening edge on the inlet side of the exhaust gas bypass passage of the turbine housing according to one embodiment of the present disclosure. Figure 6 and Figure 7 1 and 2 schematically show a state in which the inlet-side opening edge 81 of the scroll inner wall surface 6B (the scroll flow path wall surface 6 ) is viewed from the front, that is, from the scroll flow path 60 side.

[0085] In several embodiments, such as Figure 6 、 Figure 7 As shown, the inlet-side opening edge 81 of the turbine housing 4 includes a stress concentrating portion 100 provided at the downstream end portion 83 including the downstream end 831 of the inlet-side opening edge 81. The stress concentrating portion 100 is configured so that when the inlet-side opening edge 81 is exposed to the heat of the exhaust gas, stress caused by thermal expansion concentrates on the stress concentrating portion 100.

[0086] The downstream end portion 83 is composed of a region including a downstream end 831 located downstream of each of the one end 851 and the other end 861 of the inlet-side opening edge 81. In the illustrated embodiment, the downstream end portion 83 (stress concentration portion 100) is located at the center of the inlet-side opening edge 81 in the opening width direction W. In other words, in the embodiment shown in FIG. Figure 6 When the inlet side opening edge 81 is viewed from above along the normal line N2, where the length of the inlet side opening edge 81 in the opening width direction W is the largest and the distance in the opening width direction W from one end 851 to the other end 861 is set to W1, the downstream end portion 83 (stress concentration portion 100) is arranged within a range where the distance W2 in the opening width direction W (the direction toward the other end 861 is set to positive) from the one end 851 satisfies the condition of 0.25W1≤W2≤0.75W1.

[0087] According to the above configuration, the inlet-side opening edge 81 includes a stress concentrating portion 100, located at the downstream end 83 of the inlet-side opening edge 81, where stress due to thermal expansion concentrates. Heat from the exhaust gas flowing through the turbine housing 4 initially causes stress concentration due to thermal expansion in this stress concentrating portion 100, leading to cracks. Providing this stress concentrating portion 100 at the downstream end 83 of the inlet-side opening edge 81 prevents stress concentration due to thermal expansion from occurring in portions of the inlet-side opening edge 81 other than the downstream end 83 (e.g., near one end 85 or near the other end 86), thereby suppressing cracks from occurring. The downstream end 83 of the inlet-side opening edge 81 is thicker than portions other than the downstream end 83, extending to the outer surface 45 of the turbine housing 4. This prevents these cracks from propagating through the turbine housing 4 and causing exhaust gas to leak outside the turbine housing 4.

[0088] In several embodiments, such as Figure 6 As shown, the stress concentration portion 100 (downstream end portion 83) is provided at the center portion 6C of the inlet opening 810 of the exhaust gas bypass passage 80 in the opening width direction W on the vortex flow passage wall surface 6. Figure 6 When the inlet side opening edge 81 is identified in a top view along the normal line N2 as shown, when the distance in the opening width direction W from one end 62 to the other end 63 of the vortex flow path wall surface 6 in the opening width direction W is set to W3, the stress concentration portion 100 (downstream end portion 83) is set within a range (between the central portion 6C and the two double-dotted lines in the opening width direction W) where the distance W4 in the opening width direction W from the one end 62 (the direction toward the other end 63 is set to be positive) satisfies the condition of 0.25W3≤W4≤0.75W3.

[0089] According to the above-mentioned structure, by arranging the stress concentration portion 100 in the central portion 6C of the above-mentioned opening width direction W on the vortex flow path wall 6, the crack progression distance of the turbine housing 4 (the distance from the crack generated in the stress concentration portion 100 to the progress until it penetrates the turbine housing 4) can be extended, thereby effectively suppressing the leakage of exhaust gas to the outside of the turbine housing 4.

[0090] In several embodiments, such as Figure 6 As shown, the above-mentioned stress concentration portion 100 includes a first side 101 and a second side 102, and the above-mentioned first side 101 is inclined toward one side (the left side in the figure) relative to the straight line LC connecting the upstream end 841 and the downstream end 831 on the inlet side opening edge 81 as it moves from the above-mentioned downstream end 83 toward the upstream side in the flow direction of the vortex flow path 60, and the above-mentioned second side 102 is inclined toward the other side (the right side in the figure) relative to the above-mentioned straight line LC as it moves from the downstream end 83 toward the upstream side in the flow direction of the vortex flow path 60.

[0091] In the illustrated embodiment, the first side 101 and the second side 102 extend in straight lines. Figure 6 In the embodiment shown, when the inlet side opening edge 81 is viewed from above along the normal line N2, the first side 101 and the second side 102 are each configured so that the angle α is 0°≤α≤90°. Figure 6 In the illustrated embodiment, the stress concentrating portion 100 further includes a downstream connecting portion 105 connecting the downstream end 103 of the first side 101 and the downstream end 104 of the second side 102. The downstream connecting portion 105 curves toward the downstream side of the vortex flow path 60 and includes the aforementioned downstream end 831. Furthermore, in other embodiments, the downstream connecting portion 105 may be formed as a straight line extending along the axial direction X between the downstream end 103 of the first side 101 and the downstream end 104 of the second side 102. Furthermore, in other embodiments, the downstream end 103 of the first side 101 may be directly connected to the downstream end 104 of the second side 102. Furthermore, the shape of the inlet-side opening edge 81 upstream of each of the upstream end 106 of the first side 101 and the upstream end 107 of the second side 102 is not limited to the curved shape shown in the figure, which curves toward the upstream side of the vortex flow path 60 and connects the upstream ends (106, 107) of the first side 101 and the second side 102.

[0092] According to the above-described structure, stress concentration portion 100 includes the above-described first side 101 and the above-described second side 102. In this case, stress concentration due to thermal expansion initially occurs between the downstream end 103 of the first side 101 and the downstream end 104 of the second side 102 due to the heat of the exhaust gas flowing through the turbine casing 4, causing cracks. This suppresses stress concentration due to thermal expansion near the upstream end (106, 107) of the first side 101 or the second side 102. Furthermore, according to the above-described structure, since thermal expansion due to the heat of the exhaust gas is separated into each of the first side 101 and the second side 102, stress concentration due to thermal expansion near the upstream end (106, 107) of the first side 101 or the second side 102 can be suppressed.

[0093] In addition, when the downstream end portion 83 of the inlet-side opening edge 81 is set to a shape including the above-mentioned first side 101 and the above-mentioned second side 102, compared with the previous case where the inlet-side opening edge 81 is set to a circular ring shape, an elliptical ring shape, or a rectangular ring shape, the impact on the performance of the turbine housing 4 (for example, the amount of exhaust gas flowing into the exhaust gas bypass passage 80 or the heating effect of the exhaust gas purification catalyst 18 caused by the exhaust gas passing through the exhaust gas bypass passage 80) is small.

[0094] In several embodiments, such as Figure 7 As shown, the stress concentration portion 100 includes a slit 110 extending from the downstream end portion 83 on the inlet-side opening edge 81 toward the downstream side in the flow direction of the vortex flow path 60. In the illustrated embodiment, the slit 110 is formed at the downstream end 831, but in other embodiments, the slit 110 may be formed outside the downstream end 831 of the downstream end portion 83. The slit 110 is preferably formed at a position close to the downstream end 831 of the downstream end portion 83. In addition, in other embodiments, it may also be formed at a position such as Figure 6 The downstream end portion 83 of the aforementioned inlet-side opening edge 81 including the first side 101 and the second side 102 forms a slit 110 .

[0095] According to the above-described structure, stress concentration portion 100 includes a slit 110 extending from downstream end portion 83 toward the downstream side. In this case, near tip 111 of slit 110, heat from the exhaust gas flowing through turbine housing 4 initially causes stress concentration due to thermal expansion, leading to crack formation. This prevents stress concentration due to thermal expansion from occurring in portions of inlet-side opening edge 81 other than downstream end portion 83 (e.g., near one end portion 85 or the other end portion 86). The slit 110 can be easily added to the existing turbine housing 4.

[0096] In addition, when the above-mentioned slit 110 is formed on the inlet side opening edge 81, the impact on the performance of the turbine housing 4 (for example, the amount of exhaust gas flowing into the exhaust gas bypass passage 80 or the heating effect of the exhaust gas purification catalyst caused by the exhaust gas passing through the exhaust gas bypass passage 80) is smaller than when the above-mentioned slit 110 is not formed on the inlet side opening edge 81.

[0097] The present disclosure is not limited to the above-described embodiment, and includes modified embodiments of the above-described embodiment, or appropriate combinations of these embodiments.

[0098] For example, the contents described in the above-mentioned several embodiments are understood as follows.

[0099] 1) At least one embodiment of the present disclosure provides a turbine housing (4),

[0100] The invention is configured to accommodate turbine blades (3) driven by exhaust gas discharged from a gasoline engine (1), and comprises a main body (5) and an inlet flange (9).

[0101] The main body (5) has a vortex flow path wall surface (6) inside, which forms a vortex flow path (60) formed in a vortex shape for guiding the exhaust gas to the turbine blade (3);

[0102] an exhaust gas discharge path wall surface (7) forming an exhaust gas discharge path (70) for discharging the exhaust gas having passed through the turbine blades (3); and

[0103] An exhaust gas bypass passage wall (8) forms an exhaust gas bypass passage (80) that bypasses the turbine blades (3) and connects the vortex flow path (60) and the exhaust gas discharge path (70).

[0104] The inlet flange portion (9) is provided at the upstream end (61) of the vortex flow path (60) of the main body portion (5), and an exhaust gas inlet (41) connected to the vortex flow path (60) is formed in the inlet flange portion (9).

[0105] An inlet-side opening edge (81) of the exhaust gas bypass passage (80) formed on the vortex flow path wall surface (6) is provided at a position where at least a portion of the inlet-side opening edge (81) is visible from outside the turbine housing (4) through the exhaust gas inlet port (41).

[0106] According to the structure of 1) above, at least a portion of the opening edge on the inlet side of the exhaust gas bypass passage of the turbine housing is arranged at a position that can be identified from the outside of the turbine housing through the exhaust gas inlet. In this case, the length of the vortex flow path (upstream vortex flow path 60A) between the inlet opening of the exhaust gas bypass passage and the exhaust gas inlet of the inlet flange portion is shortened. By shortening the length of the upstream vortex flow path, it is possible to suppress the heat dissipation loss in the upstream vortex flow path of the exhaust gas passing through the exhaust gas bypass passage, that is, the exhaust gas flowing from the exhaust gas inlet through the upstream vortex flow path into the exhaust gas bypass passage. As a result, since the temperature drop of the exhaust gas flowing to the downstream side of the turbine housing through the exhaust gas bypass passage can be suppressed, the temperature of the exhaust gas purification catalyst arranged on the downstream side of the turbine housing can be effectively increased.

[0107] 2) In some embodiments, based on the turbine housing (4) described in 1) above,

[0108] The inlet-side opening edge (81) includes a stress concentration portion (100), which is provided at a downstream end portion (83) including a downstream end (831) on the inlet-side opening edge (81) and is configured so that stress caused by thermal expansion is concentrated on the stress concentration portion (100).

[0109] According to the configuration in 2) above, the inlet-side opening edge includes a stress concentration portion, which is provided at the downstream end of the inlet-side opening edge and is configured to concentrate stress due to thermal expansion. Heat from the exhaust gas flowing through the turbine housing initially causes stress concentration due to thermal expansion in this stress concentration portion, leading to cracks. Providing this stress concentration portion at the downstream end of the inlet-side opening edge prevents stress concentration due to thermal expansion from occurring in portions of the inlet-side opening edge other than the downstream end, thereby suppressing cracks. The downstream end of the inlet-side opening edge has a thicker wall thickness up to the outer surface of the turbine housing than portions other than the downstream end. This prevents these cracks from progressing through the turbine housing and leaking exhaust gas to the outside of the turbine housing.

[0110] 3) In some embodiments, based on the turbine housing (4) described in 2) above,

[0111] The stress concentration portion (100) includes:

[0112] a first side (101) that is inclined toward a first straight line (straight line LC) connecting the upstream end (841) and the downstream end (842) on the inlet-side opening edge (81) as it moves from the downstream end (83) toward the upstream side in the flow direction of the vortex flow path (60);

[0113] The second side (102) is inclined toward the other side relative to the first straight line (straight line LC) as it moves from the downstream end (83) toward the upstream side in the flow direction of the vortex flow path (60).

[0114] According to the configuration in 3) above, the stress concentration area includes the first side and the second side. In this case, stress concentration due to thermal expansion initially occurs between the downstream end of the first side and the downstream end of the second side due to the heat of the exhaust gas flowing through the turbine casing, leading to crack formation. This suppresses stress concentration due to thermal expansion near the upstream end of the first side or the second side. Furthermore, according to the configuration described above, since thermal expansion due to the heat of the exhaust gas is separated into the first side and the second side, stress concentration due to thermal expansion near the upstream end of the first side or the second side can be suppressed.

[0115] 4) In some embodiments, based on the turbine housing (4) described in 2) above,

[0116] The stress concentration portion (100) includes a slit (110) extending from the downstream end portion (83) on the inlet-side opening edge (81) toward the downstream side in the flow direction of the vortex flow path (60).

[0117] According to the configuration in 4), the stress concentration portion includes a slit extending from the downstream end toward the downstream side. In this case, heat from the exhaust gas flowing through the turbine housing initially causes stress concentration due to thermal expansion near the tip of the slit, leading to crack formation. This suppresses stress concentration due to thermal expansion in areas other than the downstream end of the inlet-side opening edge. The slit can be easily added to an existing turbine housing.

[0118] 5) In some embodiments, in addition to the turbine housing (4) described in any one of 2) to 4),

[0119] The stress concentration portion (100) is provided at a central portion (6C) of the inlet opening (810) of the exhaust gas bypass passage (80) on the vortex flow passage wall surface (6) in the opening width direction (W).

[0120] According to the structure of 5) above, by arranging the stress concentration portion in the central portion of the above-mentioned opening width direction on the vortex flow path wall, the crack progression distance of the turbine housing (the distance from the crack generated in the stress concentration portion to the progress until it penetrates the turbine housing) can be extended, thereby effectively suppressing the leakage of exhaust gas to the outside of the turbine housing.

[0121] 6) In some embodiments, in addition to the turbine housing (4) described in any one of 2) to 5),

[0122] The exhaust gas discharge path (70) is configured to guide the exhaust gas from one side to the other side in the extending direction of the axis (LA) of the turbine blade (3).

[0123] A normal line (N1) passing through the center (C1) of the outlet opening (820) of the exhaust gas bypass passage (80) is configured to extend in a direction intersecting the axis (LA) of the turbine blade (3).

[0124] According to the structure of 6) above, the exhaust gas bypass passage has an outlet opening connected to the exhaust gas discharge passage, and an inlet opening connected to a vortex flow path provided on the outer peripheral side of the exhaust gas discharge passage. The exhaust gas bypass passage is configured so that a normal line passing through the center of the outlet opening extends in a direction intersecting the axis of the turbine blade. In this case, the length of the exhaust gas bypass passage (the distance from the inlet opening to the outlet opening) can be shortened compared to a case where the normal line extends in a direction extending along the axis of the turbine blade. By shortening the length of the exhaust gas bypass passage, heat dissipation loss in the exhaust gas bypass passage caused by the exhaust gas passing through the exhaust gas bypass passage can be suppressed. As a result, since the temperature drop of the exhaust gas flowing to the downstream side of the turbine housing through the exhaust gas bypass passage can be suppressed, the temperature of the exhaust gas purification catalyst arranged on the downstream side of the turbine housing can be effectively increased.

[0125] 7) In some embodiments, based on the turbine housing (4) described in 6),

[0126] In a plan view with the axis (LA) of the turbine blade (3) and the center (C1) of the outlet opening (820) therebetween,

[0127] When the angle formed by the axis line (LA) and the normal line (N1) is θ, 30°≤θ≤60° is satisfied.

[0128] According to the configuration in 7), when the angle θ satisfies 30° ≤ θ ≤ 60°, the length of the exhaust bypass passage can be shortened. Furthermore, when the angle θ satisfies 30° ≤ θ ≤ 60°, exhaust gas flowing from the outlet opening of the exhaust bypass passage into the exhaust gas discharge passage can be guided by the exhaust gas discharge passage wall surface toward the exhaust gas discharge outlet and discharged from the exhaust gas discharge outlet to the exterior of the turbine housing. In this case, the exhaust gas passing through the exhaust bypass passage can flow smoothly through the exhaust gas discharge passage, thereby minimizing heat loss in the exhaust gas discharge passage. This also minimizes temperature drops in the exhaust gas flowing downstream of the turbine housing through the exhaust bypass passage, effectively suppressing temperature increases in the exhaust gas purification catalyst located downstream of the turbine housing.

[0129] 8) At least one embodiment of the present disclosure provides a turbocharger (2),

[0130] It includes the turbine housing (4) described in any one of 1) to 7).

[0131] According to the structure of 8) above, the turbocharger can suppress the heat dissipation loss of the exhaust gas passing through the exhaust gas bypass passage in the upstream vortex flow path by shortening the distance of the above-mentioned upstream vortex flow path of the turbine housing, and can thus effectively increase the temperature of the exhaust gas purification catalyst arranged on the downstream side of the turbine housing.

[0132] 9) At least one embodiment of the present disclosure provides a gasoline engine (1) comprising:

[0133] a cylinder block (11) having a plurality of cylinders (12);

[0134] an exhaust manifold (13) for merging exhaust gases discharged from the plurality of cylinders (12), and at least a portion of the exhaust manifold (13) is disposed inside the cylinder block (11);

[0135] The turbocharger (2) described in 8) above,

[0136] The inlet flange portion (9) of the turbine housing (4) is connected to the exhaust manifold (13).

[0137] According to the configuration in 9), exhaust gas discharged from the multiple cylinders flows through the exhaust manifold and then into the vortex flow path from the exhaust gas inlet of the inlet flange. At least a portion of the exhaust manifold is disposed within the cylinder block having the multiple cylinders, and the inlet flange is connected to the exhaust manifold. In this case, heat dissipation losses in the exhaust manifold from the exhaust gas discharged from the multiple cylinders can be suppressed. By suppressing the temperature drop on the upstream side of the exhaust gas flowing toward the downstream side of the turbine housing through the exhaust gas bypass passage, the temperature of the exhaust gas purification catalyst located downstream of the turbine housing can be effectively increased.

[0138] Description of Reference Numerals

[0139] 1 gasoline engine

[0140] 2 turbochargers

[0141] 3 turbine blades

[0142] 4 Turbine housing

[0143] 5 Main body

[0144] 6 Vortex flow path wall

[0145] 6A vortex outer wall

[0146] 6B vortex inner wall

[0147] 7 Exhaust gas discharge path wall

[0148] 8 Exhaust gas bypass passage wall

[0149] 9 Inlet flange

[0150] 11 Cylinder

[0151] 12 cylinders

[0152] 13 exhaust manifold

[0153] 14 Compressed gas supply line

[0154] 15 Cooling Machine

[0155] 16 Water Jacket

[0156] 17 Refrigerant supply line

[0157] 18 Exhaust gas purification catalyst

[0158] 21 Compressor Blades

[0159] 22 Rotation axis

[0160] 23 Compressor housing

[0161] 24 bearings

[0162] 25 bearing housing

[0163] 26 Wastegate Valve

[0164] 41 Exhaust gas inlet

[0165] 42 Exhaust gas outlet

[0166] 43 Convex curved surface

[0167] 44 shield surface

[0168] 60, 60A vortex flow path

[0169] 70 Exhaust gas discharge path

[0170] 70A valve accommodation space

[0171] 71 Inclined surface

[0172] 73 Valve receiving surface

[0173] 80 Exhaust gas bypass passage

[0174] 81 Entrance side opening edge

[0175] 82 outlet side opening edge

[0176] 83 downstream end

[0177] 84 upstream end

[0178] 85 one side end

[0179] 86 Other side end

[0180] 91 flange

[0181] 100 stress concentration area

[0182] 101 First Side

[0183] 102 Second Side

[0184] 105 Downstream connecting portion

[0185] 110 Slit

[0186] 171 Cooling water storage tank

[0187] 172 Cooling water supply pipe

[0188] 173 Cooling water pump

[0189] 231 Gas inlet

[0190] 232 Gas exhaust port

[0191] 261 valve body

[0192] 262 Valve body drive unit

[0193] 810 Entrance Opening

[0194] 820 Exit Opening

[0195] C1 and C2 centers

[0196] LA axis

[0197] LC straight line

[0198] N1, N2 normals

[0199] P1 tangent point

[0200] TL Tangent

[0201] X-axis

[0202] XF Turbine Side

[0203] XR compressor side

[0204] Y Radial

Claims

1. A turbine housing configured to house turbine blades driven by exhaust gas discharged from a gasoline engine, wherein: It has a main body and an inlet flange. The main body portion has a vortex flow path wall surface inside thereof, which forms a vortex flow path formed in a vortex shape for guiding the exhaust gas toward the turbine blades; an exhaust gas discharge path wall surface forming an exhaust gas discharge path for discharging the exhaust gas having passed through the turbine blades; and an exhaust gas bypass passage wall surface forming an exhaust gas bypass passage that bypasses the turbine blades and connects the vortex flow passage and the exhaust gas discharge passage; The inlet flange portion is provided at the upstream end of the vortex flow path of the main body portion and is formed with an exhaust gas inlet connected to the vortex flow path. The inlet-side opening edge of the exhaust gas bypass passage formed on the vortex flow path wall is provided at a position where at least a portion of the inlet-side opening edge is visible from the outside of the turbine housing through the exhaust gas inlet port. The inlet-side opening edge includes a stress concentration portion provided at a downstream end portion including a downstream end of the inlet-side opening edge, and configured so that stress due to thermal expansion is concentrated on the stress concentration portion.

2. The turbine housing according to claim 1, wherein: The stress concentration portion includes: a first side that is inclined toward a first straight line connecting the upstream end and the downstream end on the inlet-side opening edge as it moves from the downstream end toward the upstream side in the flow direction of the vortex flow path; The second side is inclined toward the other side with respect to the first straight line as it moves from the downstream end toward the upstream side in the flow direction of the vortex flow path.

3. The turbine housing according to claim 1, wherein: The stress concentration portion includes a slit extending from the downstream end portion of the inlet-side opening edge toward the downstream side in the flow direction of the scroll flow path.

4. The turbine housing according to claim 1, wherein: The stress concentration portion is provided at a center portion of the inlet opening of the exhaust gas bypass passage on the swirl flow path wall surface in an opening width direction.

5. The turbine housing according to claim 1, wherein: The exhaust gas discharge path is configured to guide the exhaust gas from one side to the other side in the extending direction of the axis of the turbine blade. A normal line passing through a center of an outlet opening of the exhaust gas bypass passage is configured to extend in a direction intersecting the axis of the turbine blade.

6. The turbine housing according to claim 5, wherein: In a top view with the axis of the turbine blade and the center of the outlet opening present, When the angle formed by the axis and the normal line is θ, 30°≤θ≤60° is satisfied. 7 . A turbocharger comprising the turbine housing according to claim 1 .

8. A gasoline engine comprising: a cylinder block having a plurality of cylinders; an exhaust manifold for merging exhaust gases discharged from the plurality of cylinders, wherein at least a portion of the exhaust manifold is disposed inside the cylinder block; The turbocharger according to claim 7, The inlet flange portion of the turbine housing is connected to the exhaust manifold.

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