Artigo Completo:

Downsizing in combination with turbocharging represents the main technology trend for meeting climate relevant CO2 emission standards in gasoline engine applications. Extend-ed levels of downsizing involve increasing degrees of pulse charging. Separation of cylin-der blow downs, either with double entry turbines or valve train variability, is key for achieving enhanced rated power and low-end-torque targets in highly boosted four-cylinder engines. However, double entry turbines feature specific development challenges: The aerodynam-ic design via 3D CFD calculations presents a difficult task as well as the engine perfor-mance modeling and matching process in 1D gas exchange simulations. From a manufac-turing standpoint, casting of the turbine housing is complex especially for small displace-ment applications below 1.6 l due to e. g. thermo-mechanical boundaries. This paper demonstrates how to design and model double entry turbine performance characteristics within 1D gas exchange simulations, requiring special measured and pro-cessed turbine data, which is experimentally assessed on a hot gas test bench using a double burner setup. It is shown how the collective of the described development strate-gies can be used in assessing the potential of different turbine design concepts. This al-lows the turbocharger to be designed exactly to specific engine requirements.