Alternative energy storage systems (AESS) are receiving considerable interest today for low-cost mild-hybrid vehicles where the electrical system is substituted with mechanical or hydraulic energy storage. As these technologies are being explored, simulation tools become helpful to predict the behavior of the energy storage system during vehicle use, as well as to conduct comparative studies evaluating the energy and power density, fuel economy improvement, system weight and costs. This paper presents an energy-based modeling approach to characterize the low-frequency dynamic behavior of alternative energy storage systems for hybrid vehicle applications, with the ability to predict the energy flows and sources of energy loss during driving operations. The model aims at evaluating the potential, in terms of efficiency and fuel economy improvement, offered by non-electrified energy storage systems, such as mechanical (flywheels) or hydraulic (accumulators). The modeling tool developed is able to provide a characterization of the performance of each of the two systems starting from a characterization of the components energy conversion behavior. The paper includes a simulation study where the performance of a mechanical and hydraulic energy storage system are compared on a forward-oriented hybrid vehicle simulator, with the objective of characterizing and comparing the energy recuperation process and the energy efficiency of the two systems.

This content is only available via PDF.
You do not currently have access to this content.