Presented at a show in Germany last spring, a Mercedes Unimog implement carrier equipped with a hydrogen combustion engine carried out intensive verge mowings. The data will be used as part of the WaVe* project.

The test took place on a decommissioned section of the motorway between Bayreuth and Bamberg, in Upper Franconia, in Germany. Practical testing at low temperatures and in varied topography is an important step in the ongoing “WaVe” development project. No fewer than 18 partners are currently working together on the hydrogen combustion engine drive concept.

Mercedes Unimog: a prototype hydrogen vehicle with a converted engine

The Mercedes-Benz Unimog test vehicle is based on the Unimog U 430 implement carrier, whose natural gas engine has been specially converted to run on hydrogen. Hydrogen combustion in the engine compartment produces water, which is discharged as steam via the exhaust system. On this vehicle, the wheelbase and length of the platform are dimensioned so that the hydrogen tanks can be installed behind the cab. The four TÜV-certified, 700-bar high-pressure tanks hold a total of around 14 kilograms of gaseous hydrogen. They are combined into two double tanks, each of which is operated independently of each other with a tank control unit.

In a next development stage, the engineers aim to increase the volume to cover a regular working day. The engine delivers around 290 hp and 1000 Nm. Above all, it is noticeably quieter than its diesel equivalent.

*This project, funded by the German Federal Ministry for the Economy and Climate Protection, began in July 2021. The aim of the WaVe project is to examine the extent to which a conventional diesel engine, as a multi-energy distributor for traction and all power take-offs, can be replaced by a hydrogen-fuelled combustion engine.

Article written by Laurent Meillaud and translated by Logan King