Abstract: Methods and systems are provided for airflow control in an engine system which includes a throttle turbine generator including a turbine and a turbine generator. In one example, a method may include adjusting an angle of a throttle positioned in an engine inlet passage based on a desired airflow by taking into account the effects on the throttle angle due to rotation motion of the turbine, thereby accurately controlling airflow to the engine system. The method may further include predicting an airflow to the engine system based on the position of the throttle, thereby accurately monitoring torque of the engine system.

Abstract: Methods and systems are provided for airflow control in an engine system which includes a throttle turbine generator including a turbine and a turbine generator. In one example, a method may include adjusting an angle of a throttle positioned in an engine inlet passage based on a desired airflow by taking into account the effects on the throttle angle due to rotation motion of the turbine, thereby accurately controlling airflow to the engine system. The method may further include predicting an airflow to the engine system based on the position of the throttle, thereby accurately monitoring torque of the engine system.

Abstract: Methods and systems are provided for improving surge detection and mitigation. In one example, a surge detection method may selectively filter an aggregate of temperature-adjusted manifold pressure and boost pressure in a frequency range indicative of surge to reduce the effect of non-minimum phase behavior of throttle inlet pressure on surge detection. In addition, the noise contribution of particular engine actuators on throttle inlet pressure in the selected frequency range may be accounted for, reducing the occurrence of false surge indications.

Abstract: Methods and systems are provided for turbocharger speed control in an engine system having multiple staged charge boosting devices. In one example, compressed air is provided by a turbocharger compressor until a turbocharger speed reaches a limit.

Abstract: Methods and systems are provided for turbine temperature control in an engine system having multiple staged charge boosting devices. In one example, compressed air is provided by a turbocharger compressor until an outlet temperature of the compressor reaches a limit.