Methods and systems are provided for a branch communication valve in a twin turbocharger system. A branch communication valve may be positioned adjacent to a dividing wall separating a first scroll and a second scroll of the twin turbocharger. In an open position, the branch communication valve increases fluid communication between the first scroll and the second scroll and in a closed position, the branch communication valve decreases fluid communication between the first scroll and the second scroll.

A turbocharger includes a turbine housing having a hub-side scroll flow path and a shroud-side scroll flow path, and a turbine wheel having front edges for receiving a working fluid from the hub-side scroll flow path and the shroud-side scroll flow path. Each front edge of the turbine wheel includes a first portion for receiving the working fluid flowing out from the hub-side scroll flow path, and a second portion for receiving the working fluid flowing out from the shroud-side scroll flow path. The first portion is inclined with respect to a virtual plane including a rotational axis in a direction opposite a rotational direction of the turbine wheel. The second portion is inclined with respect to the virtual plane in the rotational direction.

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 θ and a second region 222b extending from the predetermined angle θ 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.

A turbine assembly can include a turbine housing that defines a longitudinal axis and that includes a first scroll and a first tongue at a first angle about the longitudinal axis and a second scroll and a second tongue at a second angle about the longitudinal axis, where an angular span between the first angle and the second angle is greater than 1 degree and less than 180 degrees; and a first set of vanes and a second set of vanes disposed in the turbine housing, where a vane of the first set of vanes is aligned with the first tongue and a vane of the second set of vanes is aligned with the second tongue.

An entryway system includes a divided volute turbocharger having variable turbine geometry (VTG). The turbocharger includes a turbine housing, first and second volutes separated by a wall having a first and second tongue, and a turbine housing outlet. The system also includes a turbine wheel disposed in the turbine housing and a vane ring disposed in the turbine housing between the turbine wheel and the volutes. The system includes design modifications of one or more of the VTG components and/or locations of such components to manipulate the aerodynamic forces and/or subsequent mechanical loads in the VTG mechanism of the entryway system to mitigate VTG component wear during normal usage.

In a centrifugal compressor, when the position of the tongue of the scroll section in the circumferential direction of the impeller is defined as 60° and the downstream direction in the rotation direction of the impeller is defined as the positive direction of the position in the circumferential direction, a diffuser section outer diameter distribution indicating a relationship between the position in the circumferential direction and outer diameter R of the diffuser section includes an outer diameter increasing portion where the outer diameter R increases going toward the positive direction, and in the diffuser section outer diameter distribution, the position of a start point of the outer diameter increasing portion is 150° or less, and the position of an end point of the outer diameter increasing portion is 270° or more.

A turbine housing has: a first inner member; a second inner member contacting with the first inner member; a turbine scroll flow path enclosed and defined by the first inner member and the second inner member; a first casting housing covering the first inner member at a side opposite to the second inner member; a second casting housing covering the second inner member at a side opposite to the first inner member; an aperture formed in one or both of the first casting housing and the second casting housing and including an opening that opens to an outside; a tube member arranged in the aperture and defining an inlet flow path connected to the turbine scroll flow path; and an inner opening defined by the first inner member and the second inner member and overlapping with one end of the tube member.

A scroll passage of a turbine housing includes: an outer peripheral surface extending along an axial direction of the turbine housing; an inner peripheral surface disposed inward of the outer peripheral surface; a one-side surface extending along the radial direction; an other-side surface disposed closer to an outlet of the housing; a one-side outer peripheral R portion connecting the one-side surface and the outer peripheral surface; an other-side outer peripheral R portion connecting the other-side surface and the outer peripheral surface; and an other-side inner peripheral R portion connecting the other-side surface and the inner peripheral surface. A ratio of a width dimension of the scroll passage to an R dimension of each portion is defined as a peripheral R ratio, and the peripheral R ratio has an R ratio increasing region the ratio increases from upstream to downstream in the scroll passage.

A turbine housing for an exhaust turbocharger is configured for receiving a turbine wheel rotatable about an axis. The housing includes an exhaust gas inlet, an exhaust gas outlet pointing in an outlet direction, and a single-flow, spiral exhaust gas routing. The routing has a volute and a volute outlet gap configured so that exhaust gas flows from the volute to the wheel. The routing is fluidically connected to the inlet and is defined by an internal wall of the housing. The volute has a portion which encircles the axis and has a convexity of the internal wall. The convexity, counter to the outlet direction, extends beyond the volute outlet gap. Further, sectional faces, through which the axis runs, each have a volute contour with a straight linear portion. The linear portion, conjointly with the axis, defines an angle facing the outlet that is less than or equal to 90°.

A turbine includes: a turbine blade wheel housed in a housing unit; two turbine scroll flow paths wound radially outward with respect to the turbine blade wheel and connected at positions different from each other in a circumferential direction in an outer circumferential portion of the housing unit; and two scroll outlets each communicating one of the two turbine scroll flow paths with the housing unit, the two scroll outlets formed along the circumferential direction, at least one of the two scroll outlets having a height distribution in which a height in an axial direction is lower than a surrounding height at at least one of an upstream end or a downstream end.