Analysis of Energies and Speed Profiles of Driving Cycles for Fuel Consumption Measurements

Fuel consumption of a vehicle (l·100 km -1 ) is determined in a test procedure, during which the vehicle is being driven along a defined speed profile. Apart from the procedure specifications, the speed profile itself has a major impact on the resulting fuel consumption. In this paper four important driving cycles are compared - NEDC, WLTC, FTP75 and HWY. First, just cycle speed profiles are compared by mean, maximal and minimal values. Cycle speed distribution is used as an additional method of comparison. The next step is to assess engine operation in the cycle. For this purpose a representative vehicle was defined, using the data of US EPA database. With vehicle data power and energy in the cycle can be calculated. These data are then plotted in a 3D histogram, which in this case represents the engine map. This kind of diagram enables assessment of energy distribution in the engine map, although transmission influence is not taken into account. Lastly, in the cycle the consumed energy dependence on the vehicle class is determined. The analysis shows that WLTC offers the most homogeneous distribution of all in this paper analyzed cycles.