Special Trucks, a division of Mercedes-Benz, is testing a specially modified prototype of the Unimog off-road truck that runs on hydrogen. It does not, however, use hydrogen fuel cells as usual, but a slightly modified internal combustion engine.
The prototype is based on the Unimog U 430, which has four high-pressure (700 bar) hydrogen tanks with a capacity of 14 kilograms behind its short cab. The specific engine parameters have not been released by the carmaker, but the power output is 290 hp and 1,000 Nm of torque.
The hydrogen prototype is said to be significantly quieter than the diesel alternative, producing only water, which is extracted as steam through the exhaust system. As reported by auto.cz, no greenhouse carbon dioxide is produced during the combustion of hydrogen, but because it is still burned with air, which is full of nitrogen, harmful nitrogen oxides are produced. But these can be filtered out very effectively in the exhaust system.
VIDEO: Prototype off-road hydrogen truck
The special prototype is the result of the WaVe project, which was born in 2021 in collaboration with 18 industry and technology partners. The machine was first presented this spring, but only now the carmaker has reported on the progress of the vehicle's field tests.
The Unimog is fitted with a pair of arms with a mowing head, and its tests were carried out while maintaining green areas around a disused stretch of motorway. This tested the machine's ability to operate in different temperatures and terrain, as well as refuelling at public filling stations.
"Hydrogen combustion can allow driving and working with very low emissions on construction sites, in the municipal or agricultural sector. However, reliable financing is and will be required to bring such vehicles to series maturity," said Günter Pitz, Head of Powertrain Development at Mercedes-Benz Special Trucks.
While Mercedes-Benz has focused primarily on electrification in recent years, the company also recognises that the use of hydrogen-fuelled engines can be another important means of "decarbonisation", as machines such as the Unimog are often used in harsh environments and for special roles.
