Vol. 54 No. 1 (2017)   M-FET
Technical Papers

Advanced Aerodynamic Design Technologies for High Performance Turbochargers

TAKAO YOKOYAMA
KENICHIRO IWAKIRI
TOYOTAKA YOSHIDA
TORU HOSHI
TADASHI KANZAKA
SEIICHI IBARAKI

In recent years, the fuel efficiency of automobiles has been enhanced through the supercharged downsizing of engines for passenger vehicles. To meet increasingly stricter fuel efficiency regulations, however, turbochargers that have a wider operation range and are highly efficient in comparison with existing ones are strongly required. For this reason, Mitsubishi Heavy Industries, Ltd. (MHI) worked on the clarification of the internal flow phenomenon and design improvement through large-scale flow analysis of the turbine in consideration of the engine exhaust pulsation and visualization of the flow inside the compressor recirculation flow path, with the purpose of enhancing the performance of the compressor and the turbine that govern the performance of the turbocharger. In addition, a design optimization method was applied to plan a concept to enhance the efficiency of the compressor impeller and execute design improvement of the piping for a two-stage turbocharger. As a result, we enhanced the efficiency of a variable capacity turbine at minimal flow, the efficiency of a twin-scroll turbine and the extension of the operation range and efficiency of a compressor.