J-ENG Completes Land-Based Testing of Hydrogen Engine for Large Commercial Vessels

Japan Engine Corporation (J-ENG) has completed land-based testing of its 6UEC35LSGH hydrogen-fuelled low-speed two-stroke engine, developed for large commercial vessels under Japan’s Green Innovation Fund.

During factory testing, the engine achieved a hydrogen co-firing ratio of at least 95% and reduced greenhouse gas (GHG) emissions by more than 95% compared with conventional heavy fuel oil engines, according to J-ENG.

The engine was presented to project stakeholders at J-ENG’s headquarters factory on September 7. Approval testing was also completed in the presence of classification society Nippon Kaiji Kyokai (ClassNK).

Hydrogen engine uses high-pressure direct injection

The 6UEC35LSGH uses a high-pressure direct injection system that supplies hydrogen directly into the cylinder. J-ENG said the system enables stable hydrogen combustion while supporting a high hydrogen co-firing ratio.

The engine incorporates safety measures designed to prevent hydrogen leakage, including a robust engine structure and double-walled piping for hydrogen supply lines.

The completed approval testing forms part of the development programme being undertaken by J-ENG, Kawasaki Heavy Industries and Yanmar Power Solutions.

Engine to be installed on 17,500 DWT vessel

The hydrogen engine is scheduled 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.

The vessel will undergo sea trials before onboard demonstration testing begins in April 2028. The demonstration programme will evaluate the engine’s durability and performance under actual operating conditions.

Hydrogen will be supplied to the engine through a Marine Hydrogen Fuel System (MHFS) developed and manufactured by Kawasaki Heavy Industries. Kawasaki will also develop and manufacture bunkering equipment for supplying liquefied hydrogen to vessels.

ClassNK will conduct safety assessments throughout the engine development process and during the vessel’s design, construction and operation.

Blue Harmony project supports hydrogen vessel development

The engine forms part of the Blue Harmony project, which aims to develop and commercialise hydrogen-fuelled vessels. The programme is being carried out under the New Energy and Industrial Technology Development Organization’s (NEDO) Green Innovation Fund Project for next-generation ship development.

J-ENG, Kawasaki Heavy Industries and Yanmar Power Solutions are jointly developing marine hydrogen engines and associated systems under the programme.

The project follows J-ENG’s completion in August 2025 of an ammonia-fuelled marine low-speed two-stroke engine. The company is continuing development of alternative-fuel engine technologies as the maritime industry works towards reducing greenhouse gas emissions and achieving carbon neutrality by 2050.