Research project HANNAe

From 2025 onward, new commercial vehicles registered in the European Union will have to meet legally binding CO₂ fleet targets.

These targets stipulate that commercial vehicle manufacturers must reduce the average specific CO₂ emissions of their vehicles by at least 15 percent by 2025, and at least 30 percent by 2030, with reference to the emissions of a comparable fleet in 2019/20. More efficient powertrains are required for a climate-friendly and economical use of commercial vehicles These are being conceptually developed as part of this research project.

Medium-duty commercial vehicles form the backbone of today‘s road distribution transport for a wide range of goods. This transport is mainly local and regional and includes supplies to retail companies, deliveries directly to private individuals and the distribution of letters and parcels. Typical driving routes include large proportions of urban and extra-urban traffic with frequentidling and acceleration phases. Urban and regional distribution transport mainly involves vans and medium-heavy commercial vehicles up to 12 tons. Particularly in terms of the volumes transported, these vehicles make comparatively little use of their payload capacity. Depending on the transportation task and the traffic situation, the vehicles used in this process can have specific emissions of up to 300 grams of CO₂ per ton-kilometer.

To determine the energy and power requirements of a drive train for 12-ton commercial vehicles, this subproject simulated a variety of route and speed scenarios Based on the analysis of driving distances, associated speed profiles and resulting driving resistances, a pure, specific traction energy requirement of 09 to 11 kWh per kilometer was calculated for the investigated vehicles. The criteria for defining and designing the drive train were significantly determined by the focus on energy-efficient, locally emission-free and climate-friendly operation in the deployment scenarios studied A serial hybrid powertrain, in which the combustion engine is operated with regenerative synthetic methane, was defined as a suitable concept for this purpose.

The gas engine enables the new hybrid vehicle to achieve the driving performance of conventional vehicles while benefiting from the fuel availability of the established infrastructure. Because of its favorable carbon-to-hydrogen ratio, even fossil methane releases about 25 percent less CO₂ during combustion than currently used liquid fossil fuels. Until renewable fuels penetrate the market, even hybrid vehicles fueled with fossil methane can therefore contribute to climate protection as a bridging technology in the transport sector. Its electric traction also enables low-noise and locally emission-free propulsion as well as the recovery of kinetic energy through regenerative braking. Further advantages of combining an electric motor and combustion engine into a hybrid powertrain result from the different dynamic behavior and operating efficiency profiles of the two systems. Accordingly, the research priorities in the sub project were the fuel supply chain in the production of biogas (Fraunhofer IMM), the concept of an efficient combustion engine (Fraunhofer ICT) with an exhaust gas aftertreatment system (Fraunhofer ISE) and a battery-electric energy storage system (Fraunhofer LBF) for the complete integration of traction and recovered energy.

These research results were achieved in the project HANNAe (”Highly efficient powertrain for commercial vehicles taking into account the national mobility and hydrogen strategy”). The project aimed to provide an effective innovation stimulus, as part of the economic recovery and crisis management plan to counter the impact of the corona pandemic, secure prosperity and strengthen future viability, which was implemented by the German government from August to December 2020.