Methods and systems are provided for controlling boost pressure in a staged engine system comprising a turbocharger and an upstream electric supercharger. In one example, a method may include accelerating an electric supercharger to choke the flow of air to the engine in the event of turbocharger overboost.

A system and method for improving engine emissions is described. In one example, engine emissions may be improved via increasing rotational resistance of a turbocharger while a temperature of an exhaust after treatment device is less than a threshold temperature. The system and method may reduce an amount of time for the after treatment device to reach an operating temperature.

Methods and systems are provided for addressing pre-ignition occurring while operating with blow-though air delivery. A variable cam timing device used to provide positive intake to exhaust valve overlap is adjusted in response to an indication of pre-ignition to transiently reduce valve overlap. Pre-ignition mitigating load limiting and enrichment applied during a blow-through mode is adjusted differently from those applied when blow-through air is not being delivered.

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.

An internal combustion engine arrangement, comprising an internal combustion engine, a turbo arrangement, comprising a turbine and a compressor, wherein the turbine comprises a flow control member, an electric machine operatively coupled to the turbo arrangement, and a control unit, comprising processing circuitry configured to: determine a current operating parameter of the turbine, determine a current operating parameter of exhaust gas exhausted from the internal combustion engine, and determine a current operating condition of the turbine, and in response to the current operating condition forming part of a predetermined subset of operating conditions: control the electric machine to adjust the rotational speed of the turbo arrangement, and contemporaneously control the flow control member to adjust the swallowing capacity of the turbine.

A supercharged internal combustion engine is provided that is capable of introducing EGR gas into an intake passage on an upstream side relative to a compressor. When a required WGV opening degree is less than a lower limit value WGVmin in a case in which introduction of EGR gas is started under a situation in which the temperature of an EGR valve is less than or equal to a predetermined value X1, the WGV opening degree is controlled during a protection time period T3 after introduction of EGR gas starts by using the lower limit value WGVmin as the required WGV opening degree.

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

New and/or alternative approaches to performance control in an engine system having a compressor configured to receive torque from each of a turbine placed in an exhaust output of an engine and an electric motor. A control unit for the electric motor, referred to as an ETurbo controller, is provided with each of a speed control signal and a torque control signal from an engine control unit. The ETurbo controller is configured to use the torque control signal and speed control signal to operate the electric motor without causing the compressor to exceed a speed boundary.

An internal combustion engine arrangement, comprising an internal combustion engine, a turbo arrangement, comprising a turbine and a compressor, wherein the turbine comprises a flow control member, an electric machine operatively coupled to the turbo arrangement, and a control unit, comprising processing circuitry configured to: determine a current operating parameter of the turbine, determine a current operating parameter of exhaust gas exhausted from the internal combustion engine, and determine a current operating condition of the turbine, and in response to the current operating condition forming part of a predetermined subset of operating conditions: control the electric machine to adjust the rotational speed of the turbo arrangement, and contemporaneously control the flow control member to adjust the swallowing capacity of the turbine.