Abstract: A turbocharger comprises a compressor housing, a turbine housing, and a central housing with a shaft rotatably supported therein. The shaft supports on its respective opposite ends a compressor wheel and a turbine wheel that are rotatably disposed in the compressor housing and the turbine housing, respectively. The central housing has a large water jacket near the turbine housing and substantially coextensive therewith for storing cooling water to cool bearings which support the shaft. The turbine housing accommodates a shroud including a vane holder on which fixed and movable vanes are alternately supported for directing exhaust gases to the turbine wheel through variable restrictions. The vane holder or base plate has a radially outer flange and an annular boss which position the shroud axially and radially with respect to the central housing.

Abstract: A radial turbine of a variable area nozzle type which is suitable for use as the exhaust turbine of a turbocharger for an automotive internal combustion engine requiring a quick response and a wide operating range. This turbine comprises at least two groups of variable area nozzles which may be, for instance, defined by moveable vanes, and can be individually controlled for each group to vary their sizes. By opening the variable area nozzles of the first group while the variable area nozzles of the second group are kept closed, a sufficient supercharging effect can be obtained even when the fluid flow rate is small. By opening the variable area nozzles of both the groups, the resistance to the fluid flow can be reduced and the creation of excessive back pressure at the inlet to the turbine can be avoided even when the fluid flow rate is large. In this way, not only the operating range of the turbine can be expanded but also the control accuracy particularly in small nozzle opening condition can be improved.

Abstract: A variable-displacement turbine includes a turbine wheel, and a turbine housing accommodating a turbine wheel and having an exhaust inlet tubular member for introducing a stream of exhaust gases from an engine, top and base plates having confronting parallel annular end surfaces, respectively, concentric with the turbine wheel, the top and base plates defining a passage for supplying and guiding the stream of exhaust gases through the exhaust inlet tubular member to the turbine wheel from its outer periphery, and a vane mechanism disposed annularly in surrounding relation to the turbine wheel and between the annular end surfaces.