Abstract: Systems and methods for determining the presence or absence of deposits that may accumulate within a compressor recirculation valve positioned in parallel with a turbocharger compressor are presented. The systems and methods adjust actuators to maintain engine operation such that it may be more difficult for a driver to become aware that a compressor recirculation valve diagnostic is being executed.

Abstract: Methods and systems are provided for surge control in an engine system having multiple staged charge boosting devices. In one example, responsive to a drop in driver torque demand, compressed air is continued to be provided by operating a downstream intake compressor while accelerating an upstream compressor to reduce flow through the first compressor. By increasing the compressor pressure ratio at the first compressor via operation of the second compressor, surge is reduced without degrading boosted engine performance.

Abstract: Methods are provided for identifying degradation in components of a compressor bypass valve (CBV). One method comprises commanding a periodic signal to the CBV and indicating degradation of a throttle of the CBV based on changes in pressure at an inlet of an intake throttle in response to the periodic signal.

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. Thereafter, a compressor of a downstream supercharger is operated to share the load.

Abstract: Methods are provided for improving boost pressure control in a boosted engine system. In one example, in response to an operator actuated tip-in of an accelerator pedal, an air bypass around an air compressor supplying air to an air inlet of an engine may be opened for a predetermined time, and after the predetermined time, said air bypass may be increased in response to a ratio of outlet pressure to inlet pressure of said compressor being at or around a hard surge limit. In this way, by increasing the opening of the air bypass, compressor operation may be moved out of a hard/soft surge region.

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 surge control in an engine system having multiple staged charge boosting devices. In one example, responsive to a drop in driver torque demand, compressed air is continued to be provided by operating a downstream intake compressor while accelerating an upstream compressor to reduce flow through the first compressor. By increasing the compressor pressure ratio at the first compressor via operation of the second compressor, surge is reduced without degrading boosted engine performance.

Abstract: Methods and systems are provided for determining a cylinder air charge based on a boost manifold volume of an engine. In one example, a method may include inducing a compressor surge event, and updating the boost manifold volume in response to a difference between an actual surge pressure and an expected surge pressure. The method further includes determining the cylinder air charge based on the updated boost manifold volume.

Abstract: Methods and systems for operating an engine that includes an electrically operated throttle are disclosed. In one example, mitigating actions are taken in response to degradation of the electrically operated throttle so that the engine may be operated in a way that allows a driver to reach a service area.

Abstract: Methods and systems are provided for engine speed flare control in an engine system having multiple staged charge boosting devices. In one example, during an engine start, an upstream compressor is rotated backwards via an electric motor to reduce the intake manifold pressure. The engine is then fueled based on the lower manifold pressure to reduce torque and engine speed flare until idle engine speed conditions are reached.

Abstract: Systems and methods for determining the presence or absence of deposits that may accumulate within a compressor recirculation valve positioned in parallel with a turbocharger compressor are presented. The systems and methods adjust actuators to maintain engine operation such that it may be more difficult for a driver to become aware that a compressor recirculation valve diagnostic is being executed.

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 for operating an engine that includes two compressors is disclosed. In one example, an electrically driven compressor is activated in response to conditions where a turbocharger compressor speed oscillates. The electrically driven compressor is activated to cancel engine air intake flow oscillations that may be caused by the turbocharger compressor.

Abstract: Methods and systems for operating an engine that includes a compressor and charge air cooler are disclosed. In one example, air flow through the charge air cooler is increased in response to condensation accumulating in the charge air cooler without increasing engine torque. Air flow through the charge air cooler is increased to gradually reduce condensation within the charge air cooler.

Abstract: Methods and systems are provided for reliable starting an engine during cold start. In one example, a method may include in response to an engine start request, warming up an intake manifold by compressing intake air via an electric supercharger, and adjusting an intake manifold pressure before starting a first combustion of the engine.

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.

Abstract: Methods and systems are provided for diagnosing compressor bypass valve degradation. In one example, a method may include indicating degradation of a compressor bypass valve coupled in a compressor bypass based on intake aircharge temperature measured upstream of a compressor inlet via an air charge temperature sensor.

Abstract: Systems and methods for compensating for deposits that may accumulate within a compressor recirculation valve positioned in parallel with a turbocharger compressor are presented. The systems and methods adjust actuators to maintain engine operation such that it may be more difficult for a driver to become aware that a compressor recirculation valve diagnostic is being executed.

Abstract: Methods are provided for improving boost pressure control in a boosted engine system. In one example, during a tip-in, an air bypass coupled across an intake compressor of the engine system may be kept open for a predetermined time. Keeping the air bypass open during tip-in enables the compressor to spin faster, and this faster speeds may translate into reaching a desired higher boost when the air bypass is subsequently closed in less time than heretofore possible.