Fe Coefficient – Development and Application of a Key Figure for Assessing the Efficiency of Alternative Drive Concepts in Trucks

Alternative drive concepts for trucks represent a highly promising way of reducing environmental pollution from road freight traffic. There are numerous proposals and pilot schemes pointing to the replacement of fossil fuel diesel by more sustainable energy sources. Along with drive chain electrification, it is a matter here of deploying alternative natural (gas) and synthetically generated fuels (eFuels) in combustion engines that might have to be modified. Given that a multitude of parameters on final energies, vehicle and travel route/ ambient conditions enter into the consumption calculation, it is usually difficult to compare the various drive concepts based on individually gauged consumptions/emissions. It is therefore proposed assessing the comparison on the basis of the same vehicle platform under practically the same deployment and route parameters. In other words, in order to examine an alternative energy as to its efficiency, only the vehicle drive chain is replaced - everything else remains as it is! The Fe coefficient in the heading is formulated to afford a simplified comparison of the various drive concepts under the above general conditions. Going into the Fe coefficient in each instance is solely the mean drive efficiency over the route ηE-N and the payload to total load ratio under full capacity utilisation ηkon (design efficiency). The calculated Fe coefficient provides information on consumption. The greater the Fe the higher the consumption. Under the same vehicle platform - and with consideration given to the above general conditions - the Fe coefficients of the various drive variants can be related one to the other and, in this way, the increase or decrease in consumption as against, for instance, the diesel benchmark can be established. In conclusion, the Fe coefficient is used in three case studies to assess the effectiveness as against the diesel benchmark of two electric battery (Fuso eCanter, Tesla Semi) trucks and one LNG-driven Iveco Stralis NP 400 truck.