Modelling the Use Phase of Passenger Cars in LCI

The results of previous Life Cycle Assessments indicate the ecological dominance of the vehicle's use phase compared to its production and recycling phase. Particularly the so-called weight-induced fuel saving coefficients point out the great spectrum (0.15 to 1.0 l/(100 kg · 100 km)) that affects the total result of the LCA significantly. The objective of this article, therefore, is to derive a physical based, i.e. scientific chargeable and practical approved, concept to determine the significant parameters of a vehicle's use phase for the Life Cycle Inventory.

It turns out that - besides the aerodynamic and rolling resistance parameters and the efficiencies of the power train - the vehicle's weight, the rear axle's transmission ratio and the driven velocity profile have an important influence on a vehicle's fuel consumption. The coefficient for the reduction of fuel consumption on gasoline powered vehicles ranges from 0.34 to 0.48 ltr/(100 kg × 100 km) in the New European Driving Cycle (NEDC), while the saving on diesel vehicles is somewhat lower at 0.29 to 0.33 ltr/(100 kg × 100 km) in the NEDC.