Comparison Between Different Hydrogen Fuelled Powertrains for Urban Busses

In the compelling need for the decarbonization of the transport sector, hydrogen could play a crucial role, especially in heavy duty applications where the limited specific energy of chemical batteries can significantly reduce either the payload or the operative range. Moreover, the possibility to use Hydrogen not only within Fuel Cells (FCs) systems but also as a fuel in Internal Combustion Engines (ICEs) makes it even more attractive for future sustainable transport systems. In such a framework, this work aims to compare, through numerical simulation, different hydrogen powertrain configurations designed for an urban bus application. In particular, a series hybrid architecture was chosen as a reference considering three different technologies for its Auxiliary Power Unit: two internal combustion engines fuelled with Diesel and Hydrogen respectively, and a Fuel Cell featuring almost the same power level of the internal combustion engines. The study was carried out in real world driving condition and it showed the benefits of both hydrogen powertrains on the vehicle fuel economy. Finally, in order to provide a more comprehensive overview, an analysis of the Total Cost of Ownership (TCO) was performed demonstrating that the H2-engine could achieve a significant improvement of the powertrain efficiency with investments and operating costs closer to the Diesel configuration.