Japan Engine Corporation Achieves World-First with Full-Scale Ammonia-Fueled Engine
Japan Engine Corporation (J-ENG) successfully completed the world’s first fully functional, full-scale commercial ammonia-fueled engine on August 30, 2025.
Part of Japan’s Green Innovation Fund Project
The engine was developed under the “Next-Generation Ship Development” initiative, a part of the Green Innovation Fund Project administered by the New Energy and Industrial Technology Development Organization (NEDO).
Official test runs were conducted at J-ENG’s factory from August 27 to 30, 2025, with supervision from:
- Nippon Yusen Kaisya (NYK Line)
- Nihon Shipyard (NSY)
- Japan Marine United Corporation (JMU)
- Nippon Kaiji Kyokai (ClassNK)
These test runs included performance verifications in both ammonia fuel and heavy fuel oil operation modes, post-operation inspections, and assessments of major components. ClassNK certified the engine’s “outstanding environmental performance and safety.”
Deployment on Ammonia-Fueled Carrier in 2026
The engine is set for shipment in October 2025, after which it will be installed on an ammonia-fueled medium gas carrier currently under construction at JMU Ariake Shipyard. The vessel is expected to enter service in 2026.
Over 1,000 Hours of Single-Cylinder Testing
Prior to this milestone, J-ENG completed ~1,000 hours of testing on a single-cylinder ammonia-fuel engine at Mitsubishi Heavy Industries R&D Center (Nagasaki) between May 2023 and September 2024.
Building on these insights, J-ENG manufactured the full-scale 7UEC50LSJA-HPSCR engine and began ammonia-fueled test runs in April 2025. Over the next five months, it underwent 700 hours of testing focused on:
- Performance optimization
- Safety assurance
- Leak prevention systems
- Toxic ammonia monitoring systems
The result: a fully functional engine ready for safe vessel operation and crew safety.
Industry-Leading Emissions and Efficiency
Trial data showed remarkable environmental results:
- At 100% load with 95% ammonia co-firing, N₂O emissions were ~3ppm, cutting GHG emissions by over 90%
- NOx emissions were approximately half those of heavy oil engines
- Unburned ammonia emissions were virtually zero (post-NOx SCR)
- Thermal efficiency in ammonia mode matched or surpassed heavy oil mode
Scaling Up: 60cm Bore Engine and New Factory by FY2028
Following the success of the 50cm bore engine, J-ENG is now developing a 60cm bore ammonia engine to meet anticipated market demand for a wider range of ammonia-fueled vessels. Several follow-on projects are already in development.
To support future production, J-ENG is also building a new factory—backed by a subsidized project from the Ministry of the Environment and the Ministry of Land, Infrastructure, Transport and Tourism, and funded through GX Economic Transition Bonds. The factory is set to begin operations in fiscal year 2028 and will scale production of ammonia and heavy oil engines, accelerating the rollout of zero-emission ships.
Leading the Way Toward Carbon Neutrality
As a first mover in next-generation fuel engine development, J-ENG aims to:
- Promote early adoption of ammonia-fueled engines
- Strengthen Japan’s shipping and shipbuilding sectors
- Contribute to greenhouse gas reduction in maritime logistics
- Support Japan’s commitment to carbon neutrality by 2050
