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econ. cycle

sport. cycle

BMW 528i without modification (gasoline) BMW 528i with modification (gasoline) Source: [EBERLE 2000]

0.134 0.409

0.141 0.346

0.235 0.510 IFEU 2003

IFEU Heidelberg

Tab. 2: Fuel savings test results for selected driving cycles [l/ 100 km*100 kg]


Fuel savings simulated for other BMW vehicles with FALKE show similar results in the range from 0.34 to 0.48 l/ (100 km*100 kg) in the NEDC. Fuel savings for diesel vehicles are somewhat lower at 0.29 to 0.33 l/ (100 km*100 kg). Here it must be noted, however, that diesel fuel has a higher density than gasoline fuel and therefore specific energy savings for gasoline and diesel fuels are in the same range. No relative energy savings, however, can be calculated for the tests for comparison due to the lack of data on the total fuel consumption of the respective vehicles.

The reduced energy consumption is “… attributable approximately one-third to the pri- mary reduction of weight and two-thirds to the extension of the rear axle” [EBERLE 1998]. Experts assume that differences in fuel savings with and without adjustments are rather decreasing because general optimisation of the transmission in passenger cars ([HAGEN 2002] & [EBERLE 2002]).

The “Institut für Kraftfahrwesen Aachen” (ika) studied the fuel saving potential by weight reduction in simulations and tests for vehicles without modifications in the axle trans- mission [WALLENTOWITZ et al. 1996]. Two weight reduced vehicles (VW 1,6l (990 kg) and BMW 730i (1500 kg)) have been simulated and two (Peugeot 106 (850 kg) and Ford Mondeo (1450 kg)) have been tested for validation in several driving cycles. The simulations show 0.25 and 0.21 l/ (100 km*100 kg) fuel savings in the NEDC. The simu- lations also show clear differences between the different driving cycles (Chart 8) with fuel savings being highest for the urban roads, lower for the highway and low- est for the rural main road.

Energy savings by light-weighting

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