The last environmental regulations on passenger vehicles’ emissions harden constraints on designing powertrains. A promising solution consists in vehicle electrification leading to hybrid configurations: the tank-to-wheel pollutant emissions can be drastically reduced combining features of typical battery electric vehicles adding an Internal Combustion Engine (ICE) controlled as a Range Extender (REX). Furthermore, HC and CO/CO2 emissions can be avoided using green hydrogen as fuel for the ICE; moreover, in absence of a mechanical coupling between REX and wheels the best operating conditions in terms of maximum ICE efficiency may be easily achieved. In this work, a light quadricycle (EU L6e, classification) series hybrid vehicle with four in-wheel motors is studied for the application of a range extender system. The powertrain features a 0.25 Liter hydrogen-fueled ICE, whose performance data are available thanks to an experimental campaign performed at STEMS-CNR research center; then, optimal REX operations strategies are identified, and a rule-based controller is implemented for energy management purposes of the powertrain. As a first analysis, a study on hydrogen tank sizing is performed starting from an estimation of the energy demand on the range extender; then, a study on battery pack size is conducted to understand the behavior of the engine fed with hydrogen along with an overall fuel consumption analysis for a standard drive cycle (i.e., on a flat road); the same analysis is then conducted on a Real Driving Emissions (RDE) drive cycle with road slope included to compare the results of battery sizing with respect to the previous case. A stochastic algorithm for drive cycle and road slope generation is implemented to generate RDE drive cycle to explore the behavior of the vehicle on different road load conditions which are reproduced through the cycle. Finally, a study on battery sizing is achieved. The results of the analyses exhibit configuration of battery pack which express the best tradeoff between mileage and equivalent fuel consumption.
