Search

EP-4299887-B1 - TURBOCHARGER GAS CASING AND TURBOCHARGER

EP4299887B1EP 4299887 B1EP4299887 B1EP 4299887B1EP-4299887-B1

Inventors

  • TANIGUCHI, Nao
  • HIRATANI, Fumito
  • TSUJI, TAKESHI

Dates

Publication Date
20260506
Application Date
20220328

Claims (9)

  1. A turbocharger gas casing (14) of a turbine for a turbocharger (2), comprising: a scroll part (23) forming a plurality of scroll passages (24, 26) at a same position in an axial direction of the turbine (6), wherein the plurality of scroll passages (24, 26) include a first scroll passage (24) including a first scroll passage part (30) extending in a scroll shape along a circumferential direction of the turbine (6), and a second scroll passage (26) including a second scroll passage part (34) extending in a scroll shape along the circumferential direction, the second scroll passage part (34) extending along an outer peripheral side of the first scroll passage part (30) and being connected to a nozzle part (22), wherein the first scroll passage (24) is configured so that an extension line (L1a) of a line segment (L1) connecting a farthest position (P1) from a rotational axis (O) of the turbine (6) at an inlet (24a) for an exhaust gas of the first scroll passage (24) and a position (Q1) of a tip of a tongue part (25) formed on an inner peripheral side of the first scroll passage (24) does not intersect a rotor blade (18) of the turbine (6) in a cross section of the turbine (6) orthogonal to the axial direction, and wherein the first scroll passage (24) is configured so that the extension line (L1a) does not intersect a nozzle vane (12) for introducing a flow to the rotor blade (18) of the turbine (6).
  2. The turbocharger gas casing (14) according to claim 1, wherein an inner wall surface (36) of the first scroll passage (24) includes: an outward face portion (36o) facing outward in a radial direction of the turbine (6); and an inward face portion (36i) facing inward in the radial direction of the turbine (6), the inward face portion (36i) having a surface roughness Ra greater than that of the outward face portion (36o).
  3. The turbocharger gas casing (14) according to claim 2, wherein the surface roughness Ra of the inward face portion (36i) is not less than 25 µm.
  4. The turbocharger gas casing (14) according to any one of claims 1 to 3, wherein an inner wall surface (36) of the first scroll passage (24) includes: an outward face portion (36o) facing outward in a radial direction of the turbine (6); and an inward face portion (36i) facing inward in the radial direction of the turbine (6), and wherein the outward face portion (36o) includes a projection (40) projecting outward in the radial direction.
  5. The turbocharger gas casing (14) according to claim 4, wherein the projection (40) is located upstream of the position of the tip of the tongue part (25).
  6. The turbocharger gas casing (14) according to claim 4 or 5, wherein the projection (40) has a height which is at least 20% of a passage width (W1) of the first scroll passage (24) in a direction orthogonal to the axial direction.
  7. The turbocharger gas casing (14) according to any one of claims 1 to 6, wherein the first scroll passage (24) includes a passage cross section in which a passage height (H) in the axial direction is greater than a passage height (H) in a direction orthogonal to the axial direction.
  8. The turbocharger gas casing (14) according to claim 7, wherein the passage cross section has an elliptical shape or a rectangular shape.
  9. A turbocharger (2), comprising: the turbocharger gas casing (14) according to any one of claims 1 to 8; a turbine wheel (10); and a compressor impeller (8) connected to the turbine wheel (10) via a rotational shaft (9).

Description

TECHNICAL FIELD The present invention relates to a turbocharger gas casing and a turbocharger. BACKGROUND In a turbocharger, erosion occurs due to collision of an engine combustion residue with a turbine. JP H11 - 303 642 A describes that a projection projecting radially inward is provided on a passage wall surface of a scroll passage so as to disperse a combustion residue colliding with the passage wall surface, in order to suppress erosion of the scroll passage of a turbine in a supercharger. Turbocharger gas casings of a turbine for a turbocharger having a plurality of scroll passages are further known from WO 2020/050051 A1, US 4,177,005 A1, JP 2016 132996 A. A turbocharger gas casing of a turbine for a turbocharger having guide vanes is known from JP 2014 066150 A. A turbocharger having a simplified variable geometry is known from WO 2010/123786 A2. SUMMARY Technical Problem Meanwhile, in a turbine with a double scroll structure having a plurality of scroll passages at the same position in the axial direction of the turbine, an engine combustion residue flowing into the scroll passages easily collides with a rotor blade of the turbine, easily causing erosion of the rotor blade of the turbine. In this regard, JP H11 - 303 642 A does not disclose any measures for suppressing the erosion of the rotor blade in the turbine with the double scroll structure. In view of the above, an object of the present invention is to provide a turbocharger gas casing and a turbocharger including the same, which are capable of suppressing erosion of a rotor blade in a turbine with a double scroll structure. Solution to Problem The problem is solved by a turbocharger gas casing of the present invention as defined in the appended claims. A turbocharger gas casing according to at least one embodiment of the present invention is a turbocharger gas casing of a turbine for a turbocharger, including: a scroll part forming a plurality of scroll passages at a same position in an axial direction of the turbine. The plurality of scroll passages include a first scroll passage including a first scroll passage part extending in a scroll shape along a circumferential direction of the turbine and a second scroll passage including a second scroll passage part extending in a scroll shape along the circumferential direction, the second scroll passage part extending along an outer peripheral side of the scroll passage part and being connected to a nozzle part. The first scroll passage is configured so that an extension line of a line segment connecting a farthest position from a rotational axis of the turbine at an inlet for an exhaust gas of the first scroll passage and a position of a tip of a tongue part formed on an inner peripheral side of the first scroll passage does not intersect a rotor blade of the turbine in a cross section of the turbine orthogonal to the axial direction. The first scroll passage is configured so that the extension line does not intersect a nozzle vane for introducing a flow to the rotor blade of the turbine. In order to achieve the above-described object, a turbocharger according to at least one embodiment of the present disclosure, includes: the above-described turbocharger gas casing; a turbine wheel; and a compressor impeller connected to the turbine wheel via a rotational shaft. Advantageous Effects According to at least one embodiment of the present disclosure, a turbocharger gas casing and a turbocharger including the same are provided which are capable of suppressing erosion of a rotor blade in a turbine with a double scroll structure. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view schematically showing a turbocharger 2 according to an embodiment.FIG. 2 is a view schematically showing a cross section of a turbine 6 shown in FIG. 1, which is orthogonal to the axial direction.FIG. 3 is a view showing a trajectory (CFD result) of fine particles in each of a scroll passage 024 and a scroll passage 26 as a comparative example.FIG. 4 is a view showing a trajectory (CFD result) of coarse particles in each of the scroll passage 024 and the scroll passage 26 as a comparative example.FIG. 5 is a view showing a trajectory of coarse particles in each of a scroll passage 24 and the scroll passage 26.FIG. 6 is a cross-sectional view schematically showing an example of the configuration of the turbine 6 shown in FIG. 2.FIG. 7 is a schematic cross-sectional view for describing effects of projections 40 and 42 shown in FIG. 6.FIG. 8 is a cross-sectional view for describing some examples of the configuration of the turbine 6 shown in FIG. 2.FIG. 9A is a schematic view showing an example of an A1-A1 cross section and an example of an A2-A2 cross section in FIG. 8.FIG. 9B is a schematic view showing another example of a B1-B1 cross section and another example of a B2-B2 cross section in FIG. 8.FIG. 9C is a schematic view showing an example of a C1-C1 cross section and an example of a C2-C2 cross section in FIG. 8.FIG. 10A is a