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Sustainable. Clean. Uncompromising. The Internal Combustion Engine Becomes Green

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Retrofitted zero-emission trucks to hit the road in 2023

A cutting-edge solution keeps trucks on the road while slashing their emissions by turning standard diesel into hydrogen engines.

Transport and Mobility icon Transport and Mobility

Heavy-duty vehicles such as lorries and buses are responsible for around a quarter of CO2 emissions from road transport in the EU. The EU has set ambitious targets for reducing these emissions from 2025 onwards. The EU-funded H2Engine project could make an important contribution to meeting these objectives. It demonstrated a solution that will allow customers to transform a conventional diesel truck into a ‘clean’ vehicle by retrofitting it with a hydrogen engine. The truck is upgraded with hardware and software components enabling it to run on hydrogen. “Our hydrogen technology was developed using conventional diesel and compressed natural gas (CNG) components as a base,” explains Jürgen Nadler, chief marketing officer at KEYOU, the project host. Other common components developed to meet hydrogen-specific requirements include the engine’s injection and ignition systems as well as software for the engine control unit (ECU). The H2Engine team fitted a truck with a 7.8-litre hydrogen combustion engine, upgrading the core subsystems with its ‘KEYOU-inside’ technology. They delivered proof of concept by successfully starting and powering the truck.

Retrofit for the future

There has been keen interest in hydrogen-based solutions for transport systems. Vehicles propelled by hydrogen combustion engines meet the EU’s criteria to be considered zero-emission vehicles. They emit only trace amounts of CO2, making them a front runner in the search for cleaner alternatives to fossil fuels. By making it possible to turn existing vehicles into environmentally friendly ones without loss of performance, the technology resolves the conflict between emissions, efficiency and economy. “The performance of a hydrogen combustion engine is comparable to that of a common diesel engine,” Nadler says. Compared to hydrogen fuel cells, hydrogen combustion engines offer similar technical performance with substantially higher robustness and cost-efficiency: “Considering sales price figures, fuel cell vehicles are significantly more expensive.” Once serial production volumes have been reached, the cost of producing a hydrogen combustion engine will be comparable to the cost of a CNG engine, he notes.

H2 engines pulling their weight

The H2Engine team has now set their sights on bringing their solution to the market. Internal combustion engines are more efficient at higher loads, making the heavy-duty market the most promising use case for a first deployment of the technology. Commercial road transport is a huge market: 3.9 million goods were vehicles registered in the EU, according to EUROSTAT in 2021. KEYOU has achieved TÜV approval of its hydrogen-specific components and already established several partnerships with automotive suppliers. The team is aiming for a commercial launch in 2023 and serial production from 2024 onwards, with a focus on the conversion of existing diesel vehicles.


H2Engine, zero-emission, hydrogen engine, hydrogen combustion engine, heavy-duty vehicles, CNG, injection, ignition system,ECU

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