Turbosovralimentatori per applicazione automobilistica

Since over 25 years, the Research Group has been involved in studies on exhaust turbochargers thanks to the availability of an original experimental facility that allows to perform investigations under steady and unsteady flow conditions.
In recent years, the attention has been focused on the application of turbocharging to automotive downsized gasoline engines, in conjunction with fully flexible valve control systems (VVA) and an optimised design of the intake and exhaust circuit [1]. Usually a waste-gate valve is installed as turbocharger regulating system, consequently several investigations have been developed aimed at analysing the effect on steady and unsteady turbine [2, 3] and compressor [4, 5] performance. Some theoretical aspects were taken into account, with particular reference to the development of performance predicting procedures under unsteady flow conditions in collaboration with Politecnic of Milan [6] and University of Naples Federico II [7].

Technical – scientific co-operations
 ICEG has been/is involved in a number of research projects, among which:

  • the European Project POWERFUL “POWERtrain for Future Light-duty vehicles” (7th Framework Programme), with major European car manufacturers and research centres;
  • the European Project NICE “New Integrated Combustion System for Future Passenger Car Engines (6th Framework Programme), with major European car manufacturers and research centres;
  • a research collaboration with Centre de Recherche d’Innovation Technique et Technologique en Moteurs et Acoustique Automobile (CRITT M2A) on turbocharger performance;
  • a research programme with General Motors Powertrain-Europe S.r.l. on "Parameter study of Pulsating flow in a Variable Geometry Turbine";
  • a research programme with Ferrari on “Steady and unsteady experimental investigations on automotive turbochargers”;
  • different research programmes with Centro Ricerche Fiat (CRF), especially regarding turbocharging systems for automotive engine application and their regulating devices;
  • the project titled “Turbocharging systems for downsized automotive ICE”, included in the MIUR (Ministry of Education, University and Research) “Progetti di Rilevante Interesse Nazionale” (PRIN), years 2006 and 2007;
  • a theoretical and experimental investigation on unsteady flow phenomena in automotive engines intake and exhaust circuit jointly with the Department of Energetics of Politecnico di Milano;
  • a theoretical and experimental investigation on steady and unsteady flow performance in automotive turbochargers jointly with the University of Naples Federico II;
  • technical collaborations with industries, research centres and universities, among which General Motors Powertrain Europe, Ferrari, Honeywell-Garrett, Microtecnica, Ansaldo Ricerche, Röchling Automotive Engineering, Istituto Motori CNR, University of Manchester, University of Bath, etc.

Operating capabilities
ICEG operating capabilities regard different aspects related to the definition of intake and exhaust components performance, such as:

  • development of theoretical and experimental techniques to extend the definition of turbocharger compressor and turbine steady flow characteristics (Fig.1);
  • unsteady flow investigations on components and subassemblies of ICE intake and exhaust circuit;
  • characterisation of turbocharger turbine under steady and transient conditions (Fig.2);
  • characterisation of turbocharger compressor under steady and unsteady flow conditions (Fig.3);
  • control strategies optimisation of engine valve opening to improve turbocharger transient performance;
  • development and application of unsteady flow performance prediction procedures.

Research themes
The available I/E components test facility allows to carry out several research activities, such as:

  • optimisation of the exhaust circuit geometry for automotive turbocharged engines (manifolds, junctions, etc.);
  • development of optimised control strategies to enhance the behaviour of the subsystem valves-exhaust manifold-turbine in unsteady flow conditions;
  • analysis of compressor surge in small automotive turbochargers under steady and unsteady flow conditions;
  • parametric studies on turbocharger response to the main pulse parameters;
  • development and experimental validation of advanced predicting procedures for turbocharger turbine mass flow and efficiency under unsteady flow operation.


  1. S. Marelli, M. Capobianco, “Experimental Investigation under Unsteady Flow Conditions on Turbocharger Compressors for Automotive Gasoline Engines”, 10th International Conference on Turbochargers and Turbocharging, Institution of Mechanical Engineers (IMechE), London, May 15-16, 2012.
  2. M. Capobianco, S. Marelli, “Experimental analysis of unsteady flow performance in an automotive turbocharger turbine fitted with a waste-gate valve”, Journal of Automotive Engineering, Proceedings of the Institution of Mechanical Engineers, Vol 225, Part D, pages 1087-1097, doi: 10.1177/0954407011403369, June 2011.
  3. S. Marelli, M. Capobianco, “Steady and pulsating flow efficiency of a waste-gated turbocharger radial flow turbine for automotive application”, Energy, Volume 36, Issue 1, pages 459-465, doi:10.1016/j.energy.2010.10.019, January 2011.
  4. S. Marelli, M. Capobianco, G. Zamboni, “Pulsating Flow Performance of a Turbocharger Compressor for Automotive Application”, International Journal of Heat and Fluid Flow, Volume 45, pages 158-165, doi: 10.1016/j.ijheatfluidflow.2013.11.001, February 2014.
  5. S. Marelli, C. Carraro, G. Marmorato, G. Zamboni, M. Capobianco , “Experimental Analysis on Steady Flow Performance under Unstable Operating Conditions and on Surge Limit of a Turbocharger Compressor”, Experimental Thermal and Fluid Science, Volume 53, pages 154-160, doi: 10.1016/j.expthermflusci.2013.11.025, February 2014.
  6. F. Piscaglia, A. Onorati, S. Marelli, M. Capobianco – “Unsteady behaviour in turbocharger turbines: experimental analysis and numerical simulation” – SAE Paper 2007-24-0081, 8th International Conference on Engines for Automobile (ICE 2007), Capri, September 2007.
  7. V. De Bellis , S. Marelli, F. Bozza, M. Capobianco, Experimental Investigation and 1D Simulation of a Turbocharger Compressor Close to Surge Operation, 2015-01-1720, SAE Int. J. Engines, 2015