On Auxiliary Systems in Commercial Vehicles

Abstract: As more and more focus is put on the environmental questions and the request for cleaner transportation the demand on the vehicles increases. Especially the environmental request of the public transportation that is visible to the public and operates in the centre of the city. The demand on the buses used for public transportation will increase. The whole bus must be optimised, usually only the propulsion system is on focus. The optimisation does concern the vehicle and driveline not only the diesel engine that usually are used in those buses. As the driveline get more and more efficient, for instance by hybridisation and the passenger demand for comfort increases the auxiliary systems part of the energy use of the driveline increases. That will make the auxiliary system energy use more important. This study is focused on energy consumption by the auxiliary systems. In this study, detailed vehicle simulation in ADVIS0R, ADvanced VehIcle SimulatOR using MATLABTM/SIMULINKTM is used to investigate how to reduce the auxiliary sub system systems energy consumption. The simulation model that is used is verified by measurements on a Scania hybrid fuel cell concept bus. The methods used for reducing energy and fuel consumption are better control of the auxiliary system loading vehicle driveline and selection of more energy efficient components for the auxiliary systems. The control of the auxiliary systems involves: recover some of the kinetic energy when braking and switching off, if possible, the auxiliary system load in peak load mode.