Exhaust-gas turbocharged internal combustion engine and method of operating the same

Abstract

Systems and methods are provided for controlling boost pressure in an engine system with a parallel turbocharger. One example method includes, responsive to a first condition, deactivating a first compressor of a first turbocharger, activating each first exhaust valve of each cylinder of an engine, and deactivating each second exhaust valve of each cylinder of the engine to flow exhaust gas from the engine to a second turbocharger. The method further includes, responsive to boost pressure exceeding a threshold, maintaining deactivation of the first compressor, reactivating each second exhaust valve to flow exhaust gas from the engine to both the first turbocharger and second turbocharger, and driving an electric assist device via a first turbine of the first turbocharger.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from German Patent Application No. 102015205821.2 filed March 31, 2015, the entire content of which is hereby incorporated by reference for all purposes. technical field [0003] The present disclosure relates to an exhaust-gas turbocharged internal combustion engine having at least two turbines and a switchable outlet and a method for operating an internal combustion engine of said type. Background technique [0004] In the context of the present disclosure, the expression "internal combustion engine" includes Otto cycle engines, diesel engines and also hybrid internal combustion engines utilizing a hybrid combustion process, and not only internal combustion engines but also internal combustion engines which can be connected in such a way as to drive the internal combustion engine A hybrid drive that draws power from the internal combustion engine or an electric motor that acts as a sw...

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Problems solved by technology

For this purpose, it would be necessary for a corresponding line to connect the second exhaust manifold to the first turbine, possibly by means of the use of at least one additional shut-off element, but this would disadvantageously increase the Complexity and space requirements of the upstream exhaust piping system

[0019] A further disadvantage of an activatable turbine with an activatable outlet of the type described above used as switching means is that, after activation of the outlet for the purpose of activating the turbine, the exhaust gas flow directed through the second turbine suddenly decreases because now at There is a further outlet in each cylinder (specifically the activated outlet) available for exhaust during charge exchange

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