Performance evaluation of an IC-engine with a novel partial admission turbocharger concept

Autoren

Markus Schatz, Fabian Seeger, Damian M. Vogt, Institut für Thermische Strömungsmaschinen und Maschinenlaboratorium (ITSM), Universität Stuttgart;
Sergej Koch, Denis Notheis, Uwe Wagner, Thomas Koch, Institut für Kolbenmaschinen (IFKM), Karlsruher Institut für Technologie (KIT)

Jahr

2019

Zusammenfassung

In 2015, a novel control concept for the partial admission of a turbocharger turbine named MEDUSA (Multiple Exhaust Duct with Source Adjustment) was presented at the Stuttgart International Symposium. The basic idea of this control concept is to divide the turbine inlet into several sectors along the circumference and to control the admission of the different sectors individually. This partial admission approach works similar to a Variable Nozzle Turbine (VNT) control system and allows to increase the turbine inlet pressure at low engine mass flows by closing turbine inlet segments and thus restricting the effective flow area. As a consequence higher turbocharger power output at low engine load conditions can be achieved. Contrary to a VNTturbocharger, however, the presented control system can also be used at elevated exhaust
gas temperatures as featured by spark-ignition engines, because the admission valves can be placed at the turbine periphery and cooled accordingly.
To date, only data obtained from the turbocharger test rig at the Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM) at the University of Stuttgart have been published, showing that the MEDUSA-concept does indeed yield a higher turbine pressure ratio and thus better turbocharger power output at low mass flows compared to a standard Waste-Gate turbocharger. An assessment of combined engine and turbocharger performance has not been available so far.
In the present publication, results of the first measurements of combined engine and turbocharger performance obtained from tests at the Institute of Internal Combustion Engines (IFKM) at Karlsruher Institute of Technology (KIT) will be reported. For the tests, an Audi 2,0l R4 TFSI engine has been used. Reference measurements have been done using the standard Waste-Gate turbocharger (BorgWarner KKK03). Thereafter, the test configuration has been adapted to accommodate a MEDUSA-control system designed to fit the original turbocharger turbine.
Some compromises with regard to the layout of this prototype setup due to constraints of the existing equipment, such as noticeably increased volumes between compressor and engine inlet as well as between engine outlet and turbine had to be made. Nevertheless, the MEDUSA control system shows performance improvements at low engine load and mass flow conditions as expected from layout specifications and the previous turbocharger test rig experiments.

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