Abstract

In recent years, automobile exhaust gas regulations have become stricter due to environmental problems such as global warming. A project by the Cabinet Office called the Strategic Innovation Promotion Program (SIP) began in 2014. SIP has 11 themes in total. One of them, innovative combustion technology, aimed to improve the thermal efficiency of automobiles from the existing 40% to 50%. To improve the thermal efficiency of the automobile, it was essential to improve the efficiency of the turbocharger. In this study, we developed a turbocharger for gasoline and diesel engines. First, to confirm the efficiency of the conventional turbocharger, experiments and CFD analysis of a commercial turbocharger were performed. ANSYS-CFX was used as a numerical code. To confirm the accuracy of the CFD, the CFD results were compared with the experimental results, and it had good agreement with the experimental results. From the analysis results, the loss region of the conventional turbocharger was clarified. The designed turbocharger compressor was tested as a prototype compressor. The results of the compressor had good agreement with CFD results, so it was confirmed that the accuracy of CFD and design method was valid. Finally, A one-dimensional simulation using GT-Power which is a system analysis software for automobiles was performed to evaluate the developed turbocharger on the engine. In the fifth year of the project, the target efficiency of 50% was achieved.