| 摘要 |
Embodiments for controlling boost pressure during transient conditions are disclosed. In one example, a method includes, responsive to deactivation of a first turbine of a first turbocharger, deactivating an exhaust valve of a cylinder to flow exhaust gas from the cylinder to a second turbine of a second turbocharger, and adjusting a speed of the second turbocharger via an electric machine coupled to the second turbocharger in a generator mode; and responsive to activation of the first turbine, activating the exhaust valve to flow exhaust gas from the cylinder to the first turbine and the second turbine, and adjusting the speed of the second turbocharger via the electric machine in an auxiliary drive mode. |
| 主权项 |
1. 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 first condition, 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 second condition, 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 a second exhaust gas-turbocharger, a 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 has at least two outlet openings for discharge of exhaust gases, at least one of the at least two outlet openings of each cylinder is in the form of a switchable outlet opening, each outlet opening 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 each compressor is arranged in a separate intake line of the intake system, and the separate intake lines merge, downstream of the compressors, to form an overall intake line, where each exhaust line of each switchable outlet opening of the at least two cylinders 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 exhaust line of each other outlet opening of the at least two cylinders 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 switchable outlet opening is equipped with a switchable outlet valve, a deactivated outlet valve shutting off an associated outlet opening and an activated outlet valve moving between an open position and a closed position so as to realize a valve lift Δhmax, and in so doing opening up the associated outlet opening during an opening duration Δtmax. |
