Energetic evaluation on auxiliary systems of an hydrogen hybrid minibus

The transport is currently shifting towards an electric hybridization of the powertrain and the primary target is to decrease the pollutant emissions, to enhance efficiency and contemporary maintain the current vehicle performances. In particular the range is crucial for the electric powertrain and it could be sensitively affected by the auxiliary systems consumption. In fact it represents a considerable load and its consumption could reach 34% of total energy in a vehicle as verified in this work. The carried out activity has dealt with the energy analysis of the bus in different cases study varying the number of passengers, to evaluate the real range of the vehicle in real conditions. After that, the analysis has delved to the auxiliary system of mini-buses consisting of APU (Auxiliary Power Unit), suspension air compressor, cooling fans, water pump, windscreen wiper, doors motion, lights, defrosting device, electronic management system, power steering, power braking system. Once set up different representative working parameters, the data has been acquired during real tests performed to evaluate the energy required by each device. They have been exploited to simulate the auxiliary energy incidence on the actual range of the bus in real use. The auxiliary system incidences have been evaluated on the global efficiency of the minibus monitoring the energy use of auxiliary components by developing an efficient data acquisition system. The conclusion is that the energy required by the auxiliaries is not negligible, so that the efficiency enhancement of the auxiliaries could lead through an improvement of the global energy use in the vehicle, which is particularly important for innovative means of transport which are characterized by a limited range, as the electric and the hydrogen vehicles