Development of a variable geometry inlet diffuser to increase the
Transcription
Development of a variable geometry inlet diffuser to increase the
Équipe Énergétique des Moteurs à Combustion Interne Laboratoire de Mécanique des Fluides – UMR CNRS 6598 Development of a variable geometry inlet diffuser to increase the range of high efficiency operating points of turbochargers compressor Down sizing of ICE is a well known way to reduce greenhouse gas emissions. It leads to high pressure turbocharging, with a smaller zone of high efficiency for compressor. Moreover the surge margin is reduced, and this may limit the engine operating range or reliability. The main objective of this project is to evaluate the interest of an orientable inlet diffuser. In particular, a compromise will be searched between the efficiency loss at adaptation point and the increase of high efficiency range and surge margin. The final objective is to increase partload efficiency and to reduce turbo-lag of turbocharged ICE. This work will be based on: - the use of a turbocharger test bench to characterise experimentally the VGC behaviour, under steady and unsteady conditions, the influence of inlet pipes between the compressor and the engine, of pressure oscillations generated by the engine and of rotation speed fluctuations. - the development of a phenomenological model describing the unsteady behaviour of the VG compressor. Then, it will be associated with the Selendia code, developed at the Laboratory and which describes the complete engine behaviour. The optimal command of the VGC determined by simulation will then be compared to experiments made on an engine test bench, to validate the whole study. The influence of the new turbocharging system on pollutant emissions will be checked. Contact : [email protected] ECOLE CENTRALE DE NANTES, MEMBRE DE L'INTERGROUPE DES ECOLES CENTRALES 1, rue de la Noë. B.P. 92101 44321 Nantes Cedex 3. France. Tél: 02 40 37 16 00. Télex: ECNTES 711 716 F. Fax: 02 40 74 74 06