A method for controlling a speed of a turbocharger that is in operative connection with a compressor, the steps including: provision of a setpoint for the speed of the turbocharger on the basis of a model-based precontrol for a calculation of a desired boost pressure ahead of the turbocharger; determination of an actual value for the speed of the turbocharger; control of an actuator of the turbocharger in order to compensate for the difference between the desired value and the actual value for the speed of the turbocharger. A main signal and a subsidiary signal are provided during the determination of the actual value for the speed of the turbocharger, wherein the main signal and the subsidiary signal are combined in order to validate the actual value for the speed of the turbocharger.

Various methods and systems are provided for controlling air flow through an engine by adjusting an electric turbocharger of a vehicle. In one embodiment, a system for a vehicle comprises an electric turbocharger comprising a compressor, an exhaust turbine coupled to the compressor via a shaft, and an electric machine mechanically coupled to the shaft; and a controller including a processor and instructions stored on a non-transient memory of the controller that, when executed, cause the controller to: adjust an amount of power provided to or extracted from the shaft by the electric machine based on at least one of a speed of the electric turbocharger, a cylinder pressure, and an exhaust gas temperature. By adjusting the amount of power provided to or extracted from the electric machine, the exhaust gas temperature and the speed of the electric turbocharger may be efficiently maintained within a desired operating range.

Various methods and systems are provided for controlling air flow through an engine by adjusting an electric turbocharger of a vehicle. In one embodiment, a system for a vehicle comprises an electric turbocharger comprising a compressor, an exhaust turbine coupled to the compressor via a shaft, and an electric machine mechanically coupled to the shaft; and a controller including a processor and instructions stored on a non-transient memory of the controller that, when executed, cause the controller to: adjust an amount of power provided to or extracted from the shaft by the electric machine based on at least one of a speed of the electric turbocharger, a cylinder pressure, and an exhaust gas temperature. By adjusting the amount of power provided to or extracted from the electric machine, the exhaust gas temperature and the speed of the electric turbocharger may be efficiently maintained within a desired operating range.

An electric assist turbocharger unit for use in an internal combustion engine, comprising a shaft configured for torque-transmittingly connecting a compressor to a turbine of the turbocharger unit and an electric motor configured for rotatably actuating the shaft in a first rotational direction and in an opposed second rotational direction. The engine includes an aftertreatment system, and the rotation of the shaft is designed to retard the flow of intake air through an intake passage and of exhaust gases through the aftertreatment system, thereby controlling the temperature in the aftertreatment system.

Engine controllers and control schemes are provided for managing engine state transitions requiring increased compressor pressure ratios in turbocharged engines. In some circumstances, turbo lag can be mitigated by initially transitioning the engine to an intermediate engine state that directly or indirectly increases airflow through the engine and turbocharger relative to what would be possible if the engine were immediately commanded to operate at the target engine state. After reaching a point where the desired torque is actually generated at the intermediate engine state, the operational settings are gradually reduced to the target effective firing density while increasing the operational compressor pressure ratio to the target compressor ratio.

An MG1 torque at a time of decreasing an engine speed of an engine is made larger when a turbocharging pressure by a turbocharger is higher than when the turbocharging pressure is lower. In this way, even if the losses of pumps of the engine differ due to the remaining turbocharging pressure during a transition of stopping the engine in turbocharging, it is possible to appropriately reduce the engine speed. Therefore, when the engine is being brought to a stop, it is possible to appropriately suppress vibration generated in the vehicle.

An MG1 torque at a time of decreasing an engine speed of an engine is made larger when a turbocharging pressure by a turbocharger is higher than when the turbocharging pressure is lower. In this way, even if the losses of pumps of the engine differ due to the remaining turbocharging pressure during a transition of stopping the engine in turbocharging, it is possible to appropriately reduce the engine speed. Therefore, when the engine is being brought to a stop, it is possible to appropriately suppress vibration generated in the vehicle.

A method and system are provided for adjusting a speed of a turbocharger compressor using an electric motor in response to a relative substitution rate of first and second fuels in a multi-fuel engine.

A method and system are provided for adjusting a speed of a turbocharger compressor using an electric motor in response to a relative substitution rate of first and second fuels in a multi-fuel engine.

Methods and systems for controlling a turbocharger associated with an engine. The turbocharger is operated in a region of operation creating potential surge conditions, but surge is avoided by varying the speed of the turbocharger in accordance with speed parameters determined by observing a resonant frequency of surge in the system.