A method to control an electrically-operated turbocharger in a supercharged internal combustion engine, wherein the turbocharger has: a turbine, which is inserted in an exhaust duct to rotate under the thrust of the exhaust gases and operates an electric generator, and a compressor, which is mechanically independent of the turbine, is inserted in an intake duct to increase the air pressure and is operated by an electric engine; wherein the control method comprises the steps of: establishing when the intensity of the acoustic emission in the exhaust of the internal combustion engine needs to be increased; and reducing the mechanical power actually absorbed by the electric generator relative to the available mechanical power to increase the intensity of the acoustic emission in the exhaust of the internal combustion engine.

A system for real-time modeling includes a compressor designed to operate at a compressor speed, a compressor flow rate, and a compressor pressure ratio. The system also includes a memory designed to store an operating condition matrix that plots multiple compressor pressure ratios to each of a plurality of compressor speeds, and a related operating state matrix that plots multiple compressor flow rates to each of the plurality of compressor speeds. The system also includes a compressor controller to determine a target compressor speed and a target compressor pressure ratio, and to identify a target location in the operating condition matrix based on the target compressor speed and the target compressor pressure ratio. The compressor controller also determines a target compressor flow rate by interpolating values in the operating state matrix based on the target location, and to control the compressor based on the target compressor flow rate.

A system for real-time modeling includes a compressor designed to operate at a compressor speed, a compressor flow rate, and a compressor pressure ratio. The system also includes a memory designed to store an operating condition matrix that plots multiple compressor pressure ratios to each of a plurality of compressor speeds, and a related operating state matrix that plots multiple compressor flow rates to each of the plurality of compressor speeds. The system also includes a compressor controller to determine a target compressor speed and a target compressor pressure ratio, and to identify a target location in the operating condition matrix based on the target compressor speed and the target compressor pressure ratio. The compressor controller also determines a target compressor flow rate by interpolating values in the operating state matrix based on the target location, and to control the compressor based on the target compressor flow rate.

An electric exhaust turbocharger (10) has a turbine wheel (12), a compressor wheel (14) that is non-rotatably connected to the turbine wheel (12), and an electric drive engine having an engine stator (30) and an engine rotor (54). The engine rotor (54) is fixed to a rotor shaft (52) and is connected non-rotatably to the turbine wheel (12) and the compressor wheel (14) via the rotor shaft (52). The engine rotor (54) is arranged axially between the turbine wheel (12) and the compressor wheel (14) on the rotor shaft (52). Roller bearings (60, 60) are arranged between the engine rotor (54) and the turbine wheel (12) on the one hand and between the engine rotor (54) and the compressor wheel (14) on the other hand. A single separate shaft bearing cassette (40) with a cassette frame (71) supports the two roller bearings (60, 60).

An electric exhaust turbocharger (10) has a turbine wheel (12), a compressor wheel (14) that is non-rotatably connected to the turbine wheel (12), and an electric drive engine having an engine stator (30) and an engine rotor (54). The engine rotor (54) is fixed to a rotor shaft (52) and is connected non-rotatably to the turbine wheel (12) and the compressor wheel (14) via the rotor shaft (52). The engine rotor (54) is arranged axially between the turbine wheel (12) and the compressor wheel (14) on the rotor shaft (52). Roller bearings (60, 60) are arranged between the engine rotor (54) and the turbine wheel (12) on the one hand and between the engine rotor (54) and the compressor wheel (14) on the other hand. A single separate shaft bearing cassette (40) with a cassette frame (71) supports the two roller bearings (60, 60).

A supercharger transmission case that includes both small and large impeller shaft bearing bores in a single component to avoid potential misalignment, and to allow the bores to be machined during the same machining setup by the same tool. The supercharger transmission case may be fabricated of low thermal expansion material, such as a hypereutectic metal matrix comprising aluminum and silicon, to further reduce thermal expansion of the transmission case and bearings.

A supercharger transmission case that includes both small and large impeller shaft bearing bores in a single component to avoid potential misalignment, and to allow the bores to be machined during the same machining setup by the same tool. The supercharger transmission case may be fabricated of low thermal expansion material, such as a hypereutectic metal matrix comprising aluminum and silicon, to further reduce thermal expansion of the transmission case and bearings.

A turbocharger includes a turbine wheel, a compressor wheel, a shaft coupled to the turbine wheel and the compressor wheel, and a thrust bearing. The thrust bearing includes a loaded side and an unloaded side. The loaded side bears a majority of axial loading caused by force imbalances between the turbine wheel and the compressor wheel during engine startup. The thrust bearing restricts oil flow to the unloaded side as compared to the loaded side during engine startup.

A turbocharger includes a turbine wheel, a compressor wheel, a shaft coupled to the turbine wheel and the compressor wheel, and a thrust bearing. The thrust bearing includes a loaded side and an unloaded side. The loaded side bears a majority of axial loading caused by force imbalances between the turbine wheel and the compressor wheel during engine startup. The thrust bearing restricts oil flow to the unloaded side as compared to the loaded side during engine startup.

Methods and systems for operating an engine with an electrically driven compressor are described. In one example, a model in a controller determines one or more temperatures of the electrically driven compressor to establish a power output upper threshold that is not to be exceeded by the electrically driven compressor. Various actuators may be adjusted responsive to the power output upper threshold to reduce the possibility of electrically driven compressor degradation.