Mercedes-Benz Unimog tests hydrogen combustion engine

Charlie Martin Autocar 2 mins read 19 December 2023

Mercedes-Benz[1] is testing a Unimog[2] equipped with a hydrogen[3] combustion engine, in a bid to eventually offer low-emission trucks with performance on a par with today’s diesels.

The German giant is using a Unimog U430, which packs a 7.7-litre straight six that ordinarily puts out 295bhp and 885lb ft.

These figures dip slightly when running on hydrogen to 286bhp and 738lb ft. However, Mercedes notes that the engine is “noticeably quieter” when running on the gas.

It's fed by four tanks that hold around 14kg of hydrogen at a pressure of 700bar (10,152psi).

The next step of development is to increase the volume of hydrogen aboard to allow the Unimog to complete a full working day mowing a motorway verge without refilling.

Mercedes hasn't shared any efficiency figures for the current test vehicle.

Mercedes-Benz Unimog filling with hydrogen

Mercedes describes the hydrogen combustion engine as a “complimentary” solution to decarbonisation for “special applications”, alongside battery electrification and the use of hydrogen fuel cells.

The advantage of hydrogen combustion is that it can have a significantly lower environmental impact than using fossil fuels, provided that the hydrogen is sourced by electrolysing water with renewable electricity (which emits no carbon).

Combusting hydrogen with the air – which mostly comprises nitrogen and oxygen – doesn't produce CO2 emissions. However, it does produce NOx, which is linked to respiratory problems such as asthma.

As such, hydrogen combustion is touted as more of a viable solution for commercial vehicles, which generally work outside cities and towns.

Mercedes-Benz Unimog hydrogen moving motorway verge

Günter Pitz, head of powertrain development for Mercedes-Benz Special Trucks, said: “The hydrogen combustion drive concept can serve as a blueprint for power-intensive applications in the specialty vehicle sector.

“Hydrogen combustion can make it possible to drive and work with very low emissions on construction sites, in municipal or agricultural sectors.

“To reach series maturity for such vehicles, reliable funding is and will be required."

Mercedes-Benz Trucks joins several major manfuacturers in investigating hydrogen combustion. Stellantis[4] and Toyota[5] are actively developing the technology and the Renault Group has signalled its interest through the Alpine Alpenglow concept[6].

Charlie Martin

Charlie Martin Autocar Title: Editorial Assistant, Autocar

Charlie plays a key role in setting the news agenda for the automotive industry, having joined Autocar in July 2022 after a nine-month stint as an apprentice with sister publication, What Car?. He's previously contributed to The Intercooler, and placed second in Hagerty’s 2019 Young Writer competition with a MG Metro 6R4 feature. [7][8][9]

Before he joined the automotive media, Charlie studied History at the University of Winchester, where he specialised in the impact of more accessible mobility on 20th Century Europe. 

He is the proud owner of a Fiat Panda 100HP[10], and hopes to one day add a lightweight sports car like a Caterham Seven[11] or a Lotus Elise S1[12] to his collection.

used cars for sale

Ford GALAXY 2.0 TDCi Titanium Euro 6 (s/s) 5dr 47,663miles Mercedes-Benz E-CLASS 2.1 E220 BlueTEC SE G-Tronic+ Euro 6 (s/s) 5dr 63,758miles Mercedes-Benz GLC Class 2.0 GLC300d AMG Line (Premium) G-Tronic+ 4MATIC Euro 6 (s/s) 5dr 50,467miles BMW X1 1.5 25e 10kWh Sport Auto XDrive Euro 6 (s/s) 5dr 35,219miles Petrol Plug-in Hybrid BMW 3 Series 2.0 320d M Sport Auto Euro 6 (s/s) 4dr 71,000miles Volkswagen Golf 2.0 TSI BlueMotion Tech GTI Euro 6 (s/s) 5dr 31,300miles Ford Fiesta 1.25 Zetec Euro 5 5dr 109,590miles Porsche 911 3.8 991 Carrera S PDK Euro 5 (s/s) 2dr 40,550miles Land Rover Discovery Sport 2.0 D180 MHEV R-Dynamic HSE Auto 4WD Euro 6 (s/s) 5dr (7 Seat) 28,049miles View all cars[13] Powered By

Subscribe[14]

Never miss an issue of the world's oldest car magazine – subscribe to Autocar magazine today. Subscribe[15] Log in[16] or register[17] to post comments

References

  1. ^ Mercedes-Benz (www.autocar.co.uk)
  2. ^ Unimog (www.autocar.co.uk)
  3. ^ hydrogen (www.autocar.co.uk)
  4. ^ Stellantis (www.autocar.co.uk)
  5. ^ Toyota (www.autocar.co.uk)
  6. ^ Alpine Alpenglow concept (www.autocar.co.uk)
  7. ^ What Car? (www.whatcar.com)
  8. ^ The Intercooler (www.the-intercooler.com)
  9. ^ MG Metro 6R4 feature (www.hagerty.co.uk)
  10. ^ Fiat Panda 100HP (www.autocar.co.uk)
  11. ^ Caterham Seven (www.autocar.co.uk)
  12. ^ Lotus Elise S1 (www.autocar.co.uk)
  13. ^ View all cars (www.whatcar.com)
  14. ^ Subscribe (www.autocar.co.uk)
  15. ^ Subscribe (www.autocar.co.uk)
  16. ^ Log in (www.autocar.co.uk)
  17. ^ register (www.autocar.co.uk)

Tags: