Evaluation of the efficiency of a hybrid ICE vehicle fuelled with hydrogen compared with a fuel cell vehicle, based on a simulation model

With the renewed interested in the application of hydrogen on transportation, promoted also by the EU policies, the natural technology to adopt such energy vector is the fuel cell. The aim of this paper is to compare the performances, in terms of efficiency, hybrid internal combustion engine vehicles fuelled with hydrogen and fuel cell vehicles. The potential advantages, in using the ICEs, in a parallel hybrid powertrain, even if its efficiency is lower than fuel cell one, are the more efficient transmission efficiency, due to the fact that the engine is directly connected to the wheel through a gearbox, that has traditionally a very high efficiency, while the storage system help the engine when its efficiency is very low, recovering also energy during regenerative brakes. A fuel cell vehicle is generally a series hybrid vehicle, where the fuel cell has a higher efficiency than ICE, but the energy conversion from fuel cell to the electric motor has a lower efficiency. The expected result of this comparison is that the ICE hydrogen fuelled is able to recover the great part of the efficiency Gap with a higher powertrain efficiency. The study has been made using an in-house simulation code written in ENEA, using as input data the characteristic of two different vehicles, with, their electric subsystems (battery storage, electric motors, converters etc) control strategies running fixed driving cycles (e.g. the WLTC driving cycle) and comparing the fuel consumption end the efficiency. © 2023 Institute of Physics Publishing. All rights reserved.