5.1.1 Fuel consumption and driving cycles
Fuel consumption of the selected vehicles depends on many parameters like the use and the driving behaviour. Driving cycles for several uses have been designed to con- trol emission regulations and compare the fuel consumption of different passenger cars. The ECE15 is taken as a typical cycle for urban roads, the EUDC (Extra Urban Driving Cycle) for rural main roads. The NEDC (New European Driving Cycle (Directive 97/24/EC)) (Fig. 6) adds up both and will in most cases be used as average data for specific fuel savings. The most common cycles in the U.S. are the FTP75 (Federal Test Procedure 75) and the Highway cycle, which have been considered only by [WALLENTOWITZ et al. 1996]. They represent an urban and a highway pattern and not, like the NEDC, both use patterns.
Fig. 6: The New European Driving Cycle (NEDC)
New European Driving Cycle (NEDC)
Source: [KBA 2002]
Though driving cycles like the NEDC are supposed to represent the average driving in certain use patterns, they have been criticised for not being realistic in comparison with cycles recorded in road tests. The real driving behaviour has great influence on the fuel consumption which may be reduced by 25 % with an economical driving behaviour ([WALLENTOWITZ & NEUNZIG 2002]). [EBERLE 2000] therefore also uses an economical and a sporting driving cycle. These results, however, congregate around the results for the NEDC, which will therefore be used as an average.
Emission models like [TREMOD 2001] estimate the average fuel consumption by us- ing highly differentiated consumption factors for different traffic situations. Data for the fuel consumption of the selected passenger cars are based on literature research and models. The total consumption is validated using the national energy statistics.