Objective performance evaluation on mountain routes of diesel-electric hybrid busses

The application of hybrid buses for public transport on mountain route is an attractive idea because of the low pollutant emission footprint in touristic areas and the possibility to exploit the down hill route and the frequent stops to recover energy. Nevertheless the use of these vehicles is challenging for many aspects: technologically, the winter weather conditions may have a detrimental effect on batteries and electrical components, and road profile elevation may not allow to satisfy the target speeds required by the traditional bus' stop-to-stop schedule. In order to objectively assess the possibility to employ such type of vehicles on mountain routes, the actual fuel consumption and emission, logged in field operational tests, are compared with reference optimal stop-to-stop manoeuvres calculated a posteriori, which also include the interaction with the front traffic situation. The optimal reference manoeuvres are calculated based on two multi-physics dynamic models of the series hybrid diesel-electric buses, one with lithium batteries and the second with ultra-capacitors. Here the details of the two model developed are presented and discussed together with the first stage of the validation process carried out with the experimental data collected on-board.