Abstract: A turbocharger includes: at least two scroll passages, and a first range of the nozzle flow passage into which the exhaust gas flowing through the first scroll passage is introduced does not overlap with a second range of the nozzle flow passage into which the exhaust gas flowing through the second scroll passage is introduced, in a circumferential direction of the nozzle flow passage.

Abstract: A turbocharger includes: a turbine wheel; a hub-side wall surface and a shroud-side wall surface which face each other and which together form a flow path for exhaust gas to flow into the turbine wheel; and a nozzle vane which has a shroud-side end surface facing the shroud-side wall surface and a hub-side end surface facing the hub-side wall surface and which is rotatably disposed in the flow path. The nozzle vane has a pressure surface which is, at least on a shroud side, oblique toward a downstream side of the exhaust gas with a distance in a vane height direction from the shroud-side end surface.

Abstract: A turbocharger includes a turbine wheel, a hub-side wall surface and a shroud-side wall surface which face each other and which together form a flow path for exhaust gas to flow into the turbine wheel, and a plurality of nozzle vanes each of which is rotatably disposed on one of the hub-side wall surface or the shroud-side wall surface in the flow path. A throat formed between adjacent two of the plurality of nozzle vanes has a narrower throat width at a position of a first end surface of each of the adjacent two nozzle vanes facing the other of the hub-side wall surface or the shroud-side wall surface than a throat width at a middle position between the first end surface and a second end surface on an opposite side to the first end surface of each of the adjacent two nozzle vanes.

Abstract: A turbine includes: a turbine impeller; a housing disposed so as to enclose the turbine impeller and including a scroll passage positioned on an outer circumferential side of the turbine impeller; a nozzle vane disposed inside an intermediate flow passage which is positioned, in an exhaust gas flow direction, on a downstream side of the scroll passage and on an upstream side of the turbine impeller; a plate disposed on a side of the intermediate flow passage with respect to an inner circumferential wall part of the housing, defining an inner circumferential boundary of the scroll passage, so as to face the intermediate flow passage such that a gap is formed between the plate and the inner circumferential wall part in an axial direction; and at least one guide vane disposed in the gap between the inner circumferential wall part and the plate in the axial direction.

Abstract: A two-stage turbo system includes: a high-pressure stage turbocharger having a high-pressure stage turbine disposed in an exhaust passage of an engine; and a low-pressure stage turbocharger which includes a low-pressure stage turbine disposed downstream of the high-pressure stage turbine in the exhaust passage, and which is larger in size than the high-pressure stage turbocharger. The low-pressure stage turbine includes at least two scroll passages including a first scroll passage and a second scroll passage, which together form a scroll part for introducing exhaust gas into a nozzle flow passage of the low-pressure stage turbine. The scroll part is configured such that a first range of the nozzle flow passage into which the exhaust gas passing through the first scroll passage is introduced does not overlap with a second range of the nozzle flow passage into which the exhaust gas passing through the second scroll passage is introduced, in a circumferential direction of the nozzle flow passage.

Abstract: When A is a flow-path cross-sectional area of the scroll part, and R is a distance from a centroid of a flow-path cross-section of the scroll part to a rotational axis of the turbine rotor blade, the scroll part is configured so that a first graph, having a horizontal axis representing an angular position ? in a circumferential direction of the scroll part and a vertical axis representing ratio A/R of the flow-path cross-sectional area A to the distance R, at least partially has a concave distribution. The scroll part includes a first section belonging to a first angular range in the circumferential direction, and a second section belonging to a second angular range downstream of the first angular range in the circumferential direction and having a smaller throat width than a throat width of the first section in an axial direction of the turbine rotor blade.

Abstract: Suction surfaces of blades of this radial turbine each have: a leading edge side of blade tip including a leading edge and the boundary between the suction surface and the tip; and a trailing edge side of blade tip including a trailing edge and the boundary between the suction surface and the tip. The leading edge side of blade tip forms a concave curved surface which is recessed towards the side opposite to the rotation side in a radial view. The trailing edge side of blade tip forms a convex curved surface which protrudes towards the rotation side in a radial view.

Abstract: This turbocharger (10A) is provided with: a nozzle flow passage (35) for radially inwardly guiding gas from a scroll flow passage (34) and supplying the gas to a turbine wheel (12); and a nozzle mount (51) provided on the bearing housing (16) side of the nozzle flow passage (35). The turbocharger (10A) is further provided with: a vane (53) for adjusting the amount of introduced gas in the nozzle flow passage (35); and a heat shielding part (80) for minimizing heat transfer across the nozzle mount (51) from the turbine housing (31) side to the bearing housing (16) side.

Abstract: A turbocharger (10) comprising: a rotating shaft (14); a turbine wheel (12); a turbine housing (31); a scroll flowpath (34) having gas flowing therethrough that rotates and drives the turbine wheel (12); a nozzle flowpath (35) that guides gas radially inwards from the scroll flowpath (34) and supplies gas to the turbine wheel (12); and a vane (53) that adjusts the amount of gas introduced in the nozzle flowpath (35). The vane (53) comprises a guide section (60) that guides the gas flow (F) in the turbine wheel (12) radially inwards.

Abstract: A turbine includes a housing including an inlet, an outlet, and a shroud section having a shroud surface extending between the inlet and the outlet; and a turbine impeller housed in the housing and including a hub and a plurality of blades disposed on an outer peripheral surface of the hub, each of the blades having a side edge extending along the shroud surface. The side edge of each of the blades has a side-edge upstream portion disposed on a side of the inlet, and a side-edge downstream portion disposed on a side of the outlet. The shroud surface has a shroud upstream portion disposed on the side of the inlet and extending along the side-edge upstream portion, and a shroud downstream portion disposed on the side of the outlet and extending along the side-edge downstream portion.

Abstract: A variable geometry turbocharger (100) includes a bearing housing (10) including a bearing-housing side support portion (40) configured to support a radially outer portion (38) of a nozzle mount (16) from a side opposite to a scroll flow passage (4) in an axial direction of a turbine rotor (2), and wherein at least one of the following condition (a) or (b) is satisfied: (a) the bearing-housing side support portion (40) includes at least one bearing-housing side recess portion (46) formed so as to be recessed in the axial direction so as not to be in contact with the radially outer portion (38); (b) the radially outer portion (38) of the nozzle mount (16) includes at least one nozzle-mount side recess portion (62) formed so as to be recessed in the axial direction so as not to be in contact with the bearing-housing side support portion (40).

Abstract: A turbine for a turbocharger includes: a turbine impeller coupled to a compressor impeller via a rotational shaft; a turbine casing disposed so as to cover the turbine impeller, the turbine casing including a scroll flow passage and a scroll outlet portion disposed on an inner side, in a radial direction, of the scroll flow passage, for guiding exhaust gas from the scroll flow passage to the turbine impeller; and a back-surface side member disposed so as to face a back surface of the turbine impeller. The back-surface side member includes a protruding portion disposed on an impeller facing surface which faces the back surface of the turbine impeller, the protruding portion protruding toward the back surface and extending in a circumferential direction.

Abstract: A turbine impeller includes: a hub portion coupled to an end of a rotational shaft; a plurality of main blades disposed at intervals on a peripheral surface of the hub portion; and a short blade disposed between two adjacent main blades among the plurality of main blades. An inter-blade flow channel is formed between the two adjacent main blades so that a fluid flows through the inter-blade flow channel from an outer side toward an inner side of the turbine impeller in a radial direction. In a meridional plane, a hub-side end of a leading edge of the short blade is disposed on an inner side, in the radial direction, of a hub-side end of a leading edge of the main blade.

Abstract: Provided is a casing 21 for an exhaust turbocharger turbine 2, configured so as to house a turbine rotor 23 to be driven by exhaust gas and form a spiral scroll 22 serving as a path for supplying the exhaust gas to the turbine rotor 23, wherein the scroll 22 includes a first region 222a extending from a spiral origin position 222s to a predetermined angle ? and a second region 222b extending from the predetermined angle ? to a spiral end position 222e, with the surface area of an interior wall thereof decreasing from the spiral origin position 222s toward the spiral end position 222e, and the interior wall at the first region 222a has a lower surface roughness than that at the second region 222b.

Abstract: A turbine blade configured to be coupled to a rotational shaft and rotated around an axis includes: a hub having a hub surface which is inclined with respect to the axis in a cross section along the axis; a rotor blade disposed on the hub surface; and at least one rib formed on a blade surface of the rotor blade, the at least one rib extending in a direction which intersects with a span direction of the rotor blade in a meridional plane of the rotor blade.

Abstract: When A is a flow-path cross-sectional area of the scroll part, and R is a distance from a centroid of a flow-path cross-section of the scroll part to a rotational axis of the turbine rotor blade, the scroll part is configured so that a first graph, having a horizontal axis representing an angular position ? in a circumferential direction of the scroll part and a vertical axis representing ratio A/R of the flow-path cross-sectional area A to the distance R, at least partially has a concave distribution. The scroll part includes a first section belonging to a first angular range in the circumferential direction, and a second section belonging to a second angular range downstream of the first angular range in the circumferential direction and having a smaller throat width than a throat width of the first section in an axial direction of the turbine rotor blade.

Abstract: A turbocharger includes: a turbine wheel; a hub-side wall surface and a shroud-side wall surface which face each other and which together form a flow path for exhaust gas to flow into the turbine wheel; and a nozzle vane which has a shroud-side end surface facing the shroud-side wall surface and a hub-side end surface facing the hub-side wall surface and which is rotatably disposed in the flow path. The nozzle vane has a pressure surface which is, at least on a shroud side, oblique toward a downstream side of the exhaust gas with a distance in a vane height direction from the shroud-side end surface.

Abstract: There is provided a turbine wheel includes a plurality of long blades and a plurality of short blades. A trailing edge of each short blade is positioned upstream of a trailing edge of each long blade in an axial direction of the turbine wheel, and at least one of a leading edge of each long blade or a leading edge of each short blade includes an inclined part which is inclined so that a distance to a rotational axis of the turbine wheel decreases toward a hub.

Abstract: A turbocharger includes a turbine wheel, a hub-side wall surface and a shroud-side wall surface which face each other and which together form a flow path for exhaust gas to flow into the turbine wheel, and a plurality of nozzle vanes each of which is rotatably disposed on one of the hub-side wall surface or the shroud-side wall surface in the flow path. A throat formed between adjacent two of the plurality of nozzle vanes has a narrower throat width at a position of a first end surface of each of the adjacent two nozzle vanes facing the other of the hub-side wall surface or the shroud-side wall surface than a throat width at a middle position between the first end surface and a second end surface on an opposite side to the first end surface of each of the adjacent two nozzle vanes.

Abstract: A turbine housing includes: a housing body which includes a turbine housing part housing a turbine wheel, an inlet section forming an inlet flow passage for guiding exhaust gas to the turbine housing part, an outlet section forming an outlet flow passage for discharging the exhaust gas from the turbine housing part, and a waste-gate flow passage which brings the inlet flow passage and the outlet flow passage into communication so as to bypass the turbine housing part; and a sleeve disposed along an inner wall surface of the housing body forming the waste gate flow passage, at least on a downstream side of the waste-gate flow passage of the housing body with respect to a flow direction of the exhaust gas.