The need for greenhouse gas emission reductions leads to decreasing emission limits in road traffic. The development of efficient powertrains and the use of renewable energy sources are crucial in order to meet these targets. Electrification is one of the key technologies that can help to achieve higher efficiency and lower emissions. Besides the passenger car segment, electrification has started to play a more important role in heavy-duty applications as well.
One technology that has been discussed in the last years is the electrification of heavy-duty semi-trailers. In the joint research project "evTrailer2" funded by the German Federal Ministry for Economic Affairs and Climate Action, the potential of different technologies for electrified semi-trailer systems in long-haul applications is evaluated. The overall project goal is the development of high-efficiency technologies to help reduce the fuel consumption and therefore the greenhouse gas impact of large semi-trailer trucks. The developed trailer is equipped with an electrical powertrain consisting of two electric machines and a traction battery to allow energy recuperation during breaking and downhill driving, as well as traction support for the tractor unit. In order to maximize the fuel savings, the trailer is designed as a plug-in hybrid vehicle and allows high-power recharging of the battery. For additional energy input, solar panels are installed on the sides and the roof of the trailer. In order to control the energy flows on board, a cloud-based operating strategy was developed at the Institute for Internal Combustion Engines and Powertrain Systems at TU Darmstadt. The strategy uses a predictive approach and plans the use of electric energy for the route ahead.
This paper gives a general overview of the electrified trailer and describes the working principle of the operating strategy as well as the communication between the trailer and the cloud server. A simulative potential analysis shows a fuel consumption reduction potential of 21-36 % and a potential of 14-21 % reduction in well-to-wheel CO2 emissions.