“Turbocharger modelling in MVEMs for real-time simulation of transient behaviour of automotive engines”

Theoretical simulation models are nowadays playing a role that is more and more important in the design of powertrains and related management strategies. Even if the need of experimental investigations is apparent, mathematical models are already very useful tools to improve both performance and behaviour of components and systems. Their applications range from the optimisation of the system layout, up to the definition of proper control strategies. At present, automotive engines are very complex plants, whose performance are strongly dependent from the behaviour and matching between components and subsystems. Among these components, turbochargers are going to be more and more widely used not only on Diesel but also on gasoline engines (for downsizing issues). Turbocharger modelling is therefore a key issue in the development of theoretical simulation tools: both the definition and the identification of the compressor and turbine models require a careful investigation on their characteristics taking account of the possible errors and shifts between the steady-state data and the real on-engine behaviour. The paper is concerned with mathematical models for the simulation of compressors and turbines developed within the original library that the authors built up in recent years for the real-time simulation of turbocharged engines. Together with the modelling approach and the results obtained with reference to several applications, the Mean Value Model (MVM) method typically used for fast simulation is discussed taking account of the approximations which have to be introduced with this technique.