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 method for diagnosing a combustion machine, wherein the combustion machine comprises at least one internal combustion engine and one intake air line via which fresh air can be fed to the internal combustion engine. In addition, at least one intake air compressor and, upstream from the intake air compressor, a control flap are integrated into the intake air line. In one operating state of the combustion machine, the control flap is closed so far that a negative pressure relative to the ambient pressure is produced by means of the running internal combustion engine in the portion of the intake air line that lies between the control flap and the internal combustion engine, with an actual value that is associated with this negative pressure being compared with a target value and the presence or absence of leakage in this portion of the intake air line being deduced from any difference that might exist between the actual value and the target value.

An intake system for use with an internal combustion engine having one or more cylinders. The intake system including a compressor assembly having an inlet and an outlet, and where the outlet is configured to be open to and in fluid communication with at least one of the one or more cylinders. The intake system also includes a passageway extending between and in fluid communication with the inlet and the outlet and configured to direct a first flow of gasses and a controller in operable communication with the compressor assembly. Where the intake system is operable in a first mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the outlet, and a second mode in which the majority of gasses of the first flow of gasses flow through the passageway toward the inlet.

A method for controlling and/or regulating an exhaust gas turbocharger of an internal combustion engine, the exhaust gas turbocharger being protected against an exceeding of a maximum rotational speed, an actual boost pressure being compared with a setpoint boost pressure. The risk of a maximum rotational speed of the exhaust gas turbocharger being exceeded is prevented in that a manipulated variable assigned to the exhaust gas turbocharger is compared with a manipulated variable limit characteristic and is limited, if necessary, the manipulated variable limit characteristic having a time-limited, first portion and a chronologically subsequent, second portion following a change in the setpoint boost pressure, the first portion ending after a predetermined target time, the second portion of the manipulated variable limit characteristic being reduced with respect to the first portion in such a way that the maximum rotational speed of the exhaust gas turbocharger is not reached.

A method is disclosed for controlling a compression release brake mechanism in a combustion engine. The method comprises: determining a desired exhaust manifold gas pressure level; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling a brake pressure valve and a variable turbine geometry by said control parameters, to drive one of the control parameters to a set first maximum level; and, while maintaining the first of the set of control parameters at the set first maximum level, controlling an exhaust gas recirculation valve by said control parameters in a closed loop to allow exhaust gas to recirculate towards an air inlet system while driving a second of the set of control parameters to a set second maximum level.

A temporal change of a turbo rotation speed of a turbocharger is detected for each cycle of an engine. A first vibration component corresponding to each of cylinders is specified from a pulsation component included in the temporal change of the turbo rotation speed, and the first vibration components for each of the cylinders are integrated over a plurality of cycles. A variation of combustion states in the plurality of cylinders is calculated by comparing integration results among the cylinders.

A temporal change of a turbo rotation speed of a turbocharger is detected for each cycle of an engine. A first vibration component corresponding to each of cylinders is specified from a pulsation component included in the temporal change of the turbo rotation speed, and the first vibration components for each of the cylinders are integrated over a plurality of cycles. A variation of combustion states in the plurality of cylinders is calculated by comparing integration results among the cylinders.

An internal combustion engine including a block, a head coupled to the block to at least partially define a cylinder therebetween, and a compressor assembly having an inlet and an outlet in fluid communication with the cylinder. Where the compressor is operable in a first mode, in which a first portion of the gasses exiting the outlet are directed to the cylinder and a second portion of the gasses exiting the outlet is recirculated back to the inlet.

A power unit for use with an internal combustion engine including a compressor housing, a compressor wheel positioned within and rotatable with respect to the compressor housing, a shaft coupled to the compressor wheel and rotatable together therewith, a motor assembly in operable communication with the shaft, and a controller in operable communication with the motor assembly. Where the controller is adjustable between a first mode of operation, in which the motor assembly applies torque to the shaft in a first direction of rotation, and a second mode of operation, in which the motor assembly unit applies torque to the shaft in a second direction of rotation opposite the first direction of rotation.

A recirculation system for a power system is disclosed. The recirculation system may determine, according to a sequence for individually activating a plurality of turbochargers of an engine, that a designated turbocharger of the plurality of turbochargers is to be activated. The recirculation system may cause a recirculation valve of a recirculation line to open to increase an airflow between an intake manifold and a compressor of the designated turbocharger.