Mobility: Hydrogen engine for off-road applications

In order to decarbonize the transport sector, heavy commercial vehicles and non-road mobile work machines are increasingly coming to the fore. Vehicle and engine manufacturers, suppliers and science have therefore joined forces in the "PoWer" project to comprehensively investigate the cross-application use of hydrogen engine drive train concepts for construction and agricultural applications. The automotive supplier MAHLE is leading the project, in which the Karlsruhe Institute of Technology (KIT) is involved with three institutes. The Federal Ministry for Economic Affairs and Climate Protection is funding PoWer for three years with around 5 million euros, and the project is supported by TÜV Rheinland.

Due to their properties such as high efficiency, robustness and low raw emissions, hydrogen engines offer many advantages that make them particularly suitable for applications in construction and agricultural machinery. It is also possible to convert conventional combustion engines of, for example, excavators, combine harvesters or conveyor vehicles to hydrogen engines. In order to be able to implement the technology in the future, three KIT institutes are investigating hydrogen combustion in engines, suitable exhaust gas catalysts and the behavior of materials under hydrogen in the PoWer project.

Efficient use of hydrogen in complex engines

"Due to the low ignition limit and the wide flammability limits of hydrogen, unwanted self-ignition can occur. This must be avoided at all costs in order not to risk engine damage," says Dr. Uwe Wagner from the Institute for Piston Machines (IFKM) at KIT about the challenges. The researchers at the IFKM are therefore investigating how hydrogen-based fuel can be used most efficiently and safely in engines of construction and agricultural machinery - whether with intake manifold or direct injection. "In addition, the geometry of the engine and lubricating oil inputs into the combustion chamber play a decisive role in ensuring smooth combustion," says Wagner. In order to test and optimize various injection strategies and engine parameters, the researchers use a single-cylinder research unit and a multi-cylinder engine.

Environmentally friendly energy source for off-road applications

"In order to comply with current and future exhaust gas limits, it is necessary to provide efficient exhaust gas catalysts in addition to low-emission engine operation," explains Dr. Patrick Lott from the Institute of Technical Chemistry and Polymer Chemistry (ITCP) at KIT. "The specific operating conditions of hydrogen engines are sometimes challenging for the catalysts," says Lott. The ITCP team is therefore investigating how existing catalyst systems behave in interaction with hydrogen engines. One of the aims is to improve their durability and efficiency in order to adapt them to the new operating conditions. At the same time, the researchers are developing innovative concepts for exhaust gas aftertreatment so that hydrogen can be used as an environmentally friendly energy source in off-road applications.

Impact of Hydrogen on Materials

"Contact with hydrogen can significantly reduce the strength and deformability of metallic materials," explains Dr. Stefan Guth from the Institute of Applied Materials - Materials Science (IAM-WK) at KIT. In the project, the scientists at the IAM-WK are therefore investigating how hydrogen affects typical materials used in combustion engine components. To do this, they are conducting mechanical material tests under the influence of hydrogen, in particular under the cyclical loads typical of engines. A central goal of the research group is to develop and establish methods for evaluating the influence of hydrogen on material strength. "Ultimately, we want to give our industrial partners recommendations for the safe and efficient use of the materials," says Guth.

About the PoWer project

Under the leadership of MAHLE, in addition to KIT, DEUTZ AG, the German Aerospace Center (DLR), Purem GmbH, Claas KGaA mbH, the Technical University of Braunschweig, Liebherr GmbH, Nagel Maschinen- und Werkzeugfabrik GmbH, Umicore SA, NGK Europe GmbH and Castrol Limited are also involved. (ase)