Co-simulation and “control-oriented” modelling in the development of a hydraulic hybrid system.

Due to rising energy costs and emissions restrictions, vehicles manufacturers are con- tinuously forced to exploit new techniques to reduce fuel consumption and pollutant production through energy-saving solutions. In this direction hybrid architectures based on hydraulic systems seems to be promising for energy recovery strategies, but their real effectiveness is tightly related to the level of integration between sub- systems. In this work methods for mathematical simulation of hydraulic hybrid system pow- ered by internal combustion engines (ICEs) are proposed: co-simulation techniques have been applied coupling models developed both in AMESim® for the hydraulic system and in Simulink® for the engine to build up a first application on a basic hy- draulic-hybrid architecture. Taking properly care to the definition of components boundary and causality, and choosing consistently the integration time step, physical- based models can be developed to simulate the steady-state and transient behaviour of complex systems with limited computation burden (i.e., faster than real-time). A model of a basic hydraulic-hybrid system powered by an ICE is presented in the paper and its performance with reference to a given working cycle was estimated. Re- sults reported in the paper show clearly how the proposed approach can be useful to improve energy savings through the optimisation of system layout and related man- agement strategies using existing models of main components.