Japan Engine Corporation completes development of first commercial ammonia-fueled marine engine
Japan Engine Corporation (J-ENG) has announced a major milestone in maritime decarbonization — the creation of the world’s first full-scale commercial engine powered by ammonia.
On August 30, J-ENG’s Akashi plant completed assembly of the seven-cylinder 7UEC50LSJA-HPSCR engine with a 50 cm bore. The trials were carried out under the supervision of NYK Line, Nihon Shipyard, Japan Marine United (JMU), and the classification society ClassNK.
Key features
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Fuel: dual-fuel design (ammonia + heavy fuel oil)
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Environmental performance: over 90% reduction in greenhouse gas emissions when burning 95% ammonia
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Safety: negligible unburned ammonia after exhaust gas treatment; NOx emissions about half of conventional HFO engines
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Application: to be installed on a mid-sized ammonia carrier currently under construction at JMU’s Ariake shipyard, scheduled for delivery in 2026
Development timeline
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2023–2024: around 1,000 hours of testing on a single-cylinder prototype at Mitsubishi Heavy Industries’ research center in Nagasaki.
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Since 2024: an additional 700 hours of testing on the full-scale engine (fuel efficiency, leak prevention, crew safety).
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Work is already underway on a larger version with a 60 cm bore for use on a wider range of vessels.
J-ENG is also building a new manufacturing facility, funded by Japan’s GX Economic Transition Bonds, to scale up production of ammonia engines from 2028.
“We are proud to bring to market the world’s first safe and reliable ammonia-fueled engine. This marks the beginning of a new era for zero-emission shipping,” J-ENG stated.
