To investigate the energy consumption related to auxiliary devices, as a basis for optimizing the auxiliary systems’ layout and identifying potential for fuel consumption reduction, a study has been carried out at Scania CV AB. The following auxiliary devices have been investigated: Alternator, water pump, cooling fan, air compressor, air conditioning compressor, oil pump and power steering pump. Those auxiliary devices represent 5–7% of the total fuel consumption in long haulage truck applications, while for a city bus the figure could be as high as 50%. One of the challenges of evaluating the fuel consumption of auxiliary devices is the variance: it depends on many factors including road data, driver profile, ambient conditions (temperature, pres- sure, precipitation) and more. To investigate this variance, test data collected from the Scania test fleet has been analyzed. The data are used as input to a MATLAB/Simulink model of the aux- iliary systems. This way, a large population of trucks has been investigated, for many driving cycles under realistic conditions. A general model for reducing fuel consumption for auxiliary sys- tems has been developed.
QC 20140610