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]
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