Method for charge pressure control of an internal combustion engine with turbines arranged in parallel, and internal combustion engine for carrying out such a method

A method for charge pressure control of a supercharged internal combustion engine having at least one cylinder head with at least two cylinders, comprising:

• responsive to a command to reactivate a second turbine of a second exhaust-gas turbocharger from deactivated, driving an electric machine as an auxiliary drive, the electric machine at least connectable in terms of drive to a first exhaust-gas turbocharger, to additionally output power to a first compressor of the first exhaust-gas turbocharger to increase charge pressure;
• and
• responsive to a command to deactivate the second turbine from activated, absorbing power from a first turbine of the first exhaust-gas turbocharger via the electric machine for the purposes of lowering the charge pressure, where the first compressor of the first exhaust-gas turbocharger is arranged in parallel in an intake system with a second compressor of the second exhaust gas-turbocharger, the second turbine of the second exhaust gas-turbocharger and the first turbine of the first exhaust-gas turbocharger each arranged in an exhaust-gas discharge system,
• where each cylinder of the at least two cylinders has a first outlet opening and a second outlet opening for discharge of exhaust gases, the first outlet opening of each cylinder of the at least two cylinders is in the form of a switchable outlet opening, each of the first and second outlet openings of each cylinder of the at least two cylinders being adjoined by a respective exhaust line for the discharge of the exhaust gases via the exhaust-gas discharge system,
• where the intake system supplies charge air to the at least two cylinders,
• where the first compressor is arranged in a first intake line of the intake system, the second compressor is arranged in a second intake line of the intake system, and the first and second intake lines merge, downstream of the first and second compressors, to form an overall intake line,
• where each of the respective exhaust lines of each of the first outlet openings merge, with the formation of a first exhaust manifold, to form a first overall exhaust line which is connected to the second turbine of the second exhaust-gas turbocharger,
• where each of the respective exhaust lines of each of the second outlet openings merge, with the formation of a second exhaust manifold, to form a second overall exhaust line which is connected to the first turbine of the first exhaust-gas turbocharger, and
• where each of the first outlet openings is equipped with a switchable outlet valve that when deactivated shuts off an associated first outlet opening and when activated moves between an open position and a closed position so as to realize a valve lift Δhmax, and in so doing opening up the associated first outlet opening during an opening duration Δtmax.