CG rendering of the 17,500 DWT Multipurpose Vessel
Green Innovation Fund Project / Development of Marine Hydrogen Engines and MHFS. Image Credit: J-ENG

• Japan Engine Corporation says its 6UEC35LSGH ran at a hydrogen co-firing rate of at least 95% in factory tests
• GHG emissions said to be more than 95% lower than a conventional heavy fuel oil engine
• To be installed in January 2027 on a 17,500 DWT multipurpose vessel for MOL and MOL Drybulk
• Kawasaki to supply the hydrogen fuel system and develop liquefied hydrogen bunkering equipment

Japan Engine Corporation (J-ENG) says it has completed land-based testing of what it describes as the world's first hydrogen-fuelled engine for large commercial vessels.

The low-speed two-stroke 6UEC35LSGH achieved a hydrogen co-firing rate of at least 95% during factory testing, cutting greenhouse gas emissions by more than 95% compared with a conventional heavy fuel oil engine, the company said in a joint press release with its project partners on Friday.

Approval testing was carried out in the presence of classification society ClassNK, and the engine was shown to project stakeholders at J-ENG's headquarters factory on September 7.

J-ENG says stable hydrogen combustion comes from a high-pressure direct injection system that injects the fuel straight into the cylinder, with safety measures including a structure designed to prevent hydrogen leakage and double-walled piping on the hydrogen supply lines.

The engine is due to be installed in January 2027 on a 17,500 DWT multipurpose vessel being built by Onomichi Dockyard for Mitsui O.S.K. Lines (MOL) and MOL Drybulk, with onboard demonstration testing scheduled to begin in April 2028 after sea trials.

Hydrogen will reach the engine through a marine hydrogen fuel system of tanks and fuel supply equipment developed by Kawasaki Heavy Industries, which will also develop and manufacture bunkering equipment for supplying liquefied hydrogen to vessels.

The work is part of the Blue Harmony project, funded under the Green Innovation Fund of Japanese state agency NEDO, in which J-ENG, Kawasaki, and Yanmar Power Solutions are jointly developing marine hydrogen engines.

The project follows J-ENG's completion of its first commercial ammonia-fuelled two-stroke engine in August 2025.