Abstract: A variable nozzle device including an annular nozzle passage formed by a gap between two opposing wall members and at least one vane rotatably supported in the nozzle passage. The vane is formed by a strip of sheet metal contoured to have an outer aerodynamic profile, and having a hollow interior with surfaces mimicking the outer profile. The vane is affixed to a shaft having a wind-stream portion forming two contact surfaces that conformingly receive opposing portions of the interior surfaces.

Abstract: A turbocharger includes a thin-walled insert installed in the bore of the turbine housing. The insert is generally ring-shaped and is radially resilient. The insert can be made of sheet metal formed into a ring shape, and in some embodiments is a split ring. A piston is axially slidable in the bore for varying the size of the turbine nozzle. The outer surface of the piston slides against the inner surface of the insert, and in preferred embodiments a piston ring that encircles the piston engages the inner surface of the insert to substantially seal the interface between the insert and the piston.

Abstract: An exemplary vane fronting surface for a variable geometry turbine includes a white layer that comprises nitrides. Such a layer may be formed using gas nitriding. As described, trials demonstrate that such nitriding reduces friction between a vane fronting surface and vanes of a variable geometry turbine. Consequently, nitriding can enhance longevity and controllability of a variable geometry turbine.

Abstract: A variable-nozzle turbocharger includes a turbine housing and a center housing, and a generally annular nozzle ring and an array of vanes rotatably mounted to the nozzle ring such that the vanes are rotatably adjustable for regulating exhaust gas flow to the turbine wheel. An elastically deformable member is disposed between a radially inwardly facing surface of the nozzle ring and a radially outwardly facing surface of the center housing, the elastically deformable member having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to radially center the nozzle ring relative to the center housing.

Abstract: A variable-nozzle assembly comprises a nozzle ring and an array of vanes circumferentially spaced about the nozzle ring and rotatably mounted to the nozzle ring such that the vanes are variable in setting angle, and an insert having a tubular portion and an annular nozzle portion extending generally radially out from one end of the tubular portion. A plurality of axially extending holes extend through a thickness of the nozzle portion. A plurality of spacers have first ends joined to the nozzle ring, opposite second ends of the spacers being engaged in the holes and secured to the nozzle portion by welds formed at the second surface. An annular groove is defined in the second surface of the nozzle portion radially inward of and proximate to the holes. Alternatively or additionally, discrete recesses are formed in the second surface adjacent the holes. The groove and/or recesses facilitate weld penetration.

Abstract: A variable-nozzle turbocharger includes a cartridge containing a variable vane mechanism connected between the center housing and the turbine housing. The cartridge comprises an annular nozzle ring supporting an array of rotatable vanes, an insert having a tubular portion sealingly received into the bore of the turbine housing and having a nozzle portion extending radially out from one end of the tubular portion and being axially spaced from the nozzle ring with the vanes therebetween, and a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring. The turbine housing has a surface that directly contacts a surface of the nozzle ring that axially faces the insert for axially locating the nozzle ring relative to the turbine housing. A radial gap is defined between the turbine housing and the nozzle ring to allow radial movement of the nozzle ring relative to the turbine housing.

Abstract: Disclosed are retainers for a turbocharger. In one embodiment, the retainer includes a generally annular body that defines a bore and one or more channels. The bore is generally directed along a central axis of the body and can be configured to mate with a nose of a center housing of a turbocharger. The channels can be configured to accommodate vanes associated with a cartridge assembly of the turbocharger. One or more legs may extend from the retainer body and may be configured to mate with and locate the retainer relative to a cartridge assembly for the turbocharger. The retainer can also include a concave portion disposed around a perimeter of the body. The concave portion and the body may be together configured to act as a spring when the retainer is mechanically loaded in a direction having a component parallel to the central axis. Also disclosed are corresponding turbochargers.

Abstract: A turbocharger having a turbine housing defining a chamber for receiving exhaust gas, and a nozzle leading from the chamber. Exhaust gas flows from the nozzle through a turbine wheel in the chamber and changes direction from a radially inward direction in the nozzle to an axial direction downstream of the turbine wheel. A divider in the nozzle divides the nozzle into first-stage and second-stage nozzles. The divider has an upstream surface to guide exhaust gas through the first-stage nozzle and an opposite downstream surface to guide exhaust gas flowing through the second-stage nozzle. An axially slidable tubular piston, disposed in the turbine housing, has a radially inner surface extending along the axial direction and a non-flat upstream end surface. The piston also includes a curved flow-guiding surface causing the exhaust gas to change direction. In a closed position, the piston abuts the divider to close the second-stage nozzle.

Abstract: A variable-nozzle turbocharger includes a cartridge containing a variable vane mechanism connected between the center housing and the turbine housing. The cartridge comprises an annular nozzle ring supporting an array of rotatable vanes, an insert having a tubular portion sealingly received into the bore of the turbine housing and having a nozzle portion extending radially out from one end of the tubular portion and being axially spaced from the nozzle ring with the vanes therebetween, a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring, and an annular retainer ring fastened to the center housing so as to capture the nozzle ring between the retainer ring and the center housing. The retainer ring is formed as a separate part from the insert ring and is mechanically and thermally decoupled from the insert.

Abstract: A variable-vane cartridge mechanism for a turbocharger is assembled from a nozzle ring, an insert that engages a turbine housing bore, and a plurality of spacers. Holes larger in diameter than the spacers are formed in the nozzle ring and a nozzle portion of the insert, such that the spacers fit loosely in the holes. A locating fixture is engaged with the nozzle ring and insert for precisely locating these parts radially (and optionally also axially) with respect to each other; the spacers can move within the holes as needed to allow the positions of the parts to be adjusted. Once located relative to each other, the nozzle ring and insert are fixed in the desired relative positions by affixing the spacers to them, such as by welding.

Abstract: A variable-nozzle turbocharger includes a cartridge containing a variable vane mechanism connected between the center housing and the turbine housing. The cartridge comprises an annular nozzle ring supporting an array of rotatable vanes, an insert having a tubular portion sealingly received into the bore of the turbine housing and having a nozzle portion extending radially out from one end of the tubular portion and being axially spaced from the nozzle ring with the vanes therebetween, and a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring. The turbine housing has a surface that directly contacts a surface of the nozzle ring that axially faces the insert for axially locating the nozzle ring relative to the turbine housing. A radial gap is defined between the turbine housing and the nozzle ring to allow radial movement of the nozzle ring relative to the turbine housing.

Abstract: A vane assembly includes vanes each having an axle and an arm immovably connected with the vane prior to assembling the vane assembly. The vane, axle, and arm can be an integral one-piece structure formed by casting, machining, or metal injection molding. The axles engage apertures in a nozzle ring and are rotatable in the apertures about axes of the vanes. An actuator ring is assembled with the nozzle ring and is rotatable relative thereto. The actuator ring defines connecting elements that connect with cooperative connecting elements on the vane arms. Rotation of the actuator ring causes the vanes to rotate for adjusting the angles of the vanes. During assembly, the motion of inserting the axles into the apertures is also effective for placing the arms in position for connection with the actuator ring.

Abstract: An exemplary vane fronting surface for a variable geometry turbine includes a white layer that comprises nitrides. Such a layer may be formed using gas nitriding. As described, trials demonstrate that such nitriding reduces friction between a vane fronting surface and vanes of a variable geometry turbine. Consequently, nitriding can enhance longevity and controllability of a variable geometry turbine.

Abstract: A turbocharger comprises a variable nozzle device and an exhaust housing being mechanically and/or thermally decoupled from the variable nozzle device. Additional optional advantageous features are provided, including various axial and radial clearances and various sealing elements.