Japan Engine Corporation (J-ENG) completed the world’s first full-scale ammonia-fueled engine on August 30, 2025, intended for installation on an
Japan Engine Corporation (J-ENG) completed the world’s first full-scale ammonia-fueled engine on August 30, 2025, intended for installation on an Ammonia-Fueled Medium Gas Carrier (AFMGC) scheduled to enter service in 2026.
Developed as part of the Green Innovation Fund Project under NEDO’s “Next-Generation Ship Development” initiative, the engine is a 7-cylinder, 50 cm bore dual-fuel design capable of operating on both ammonia and heavy fuel oil. Official test runs conducted from August 27–30, 2025, under the supervision of NYK Line, NSY, JMU, and ClassNK, confirmed its performance, environmental compliance, and safety, including leak prevention measures, with certification granted by ClassNK.
Prior development included roughly 1,000 hours of testing on a single-cylinder ammonia engine between May 2023 and September 2024 at Mitsubishi Heavy Industries’ Nagasaki R&D Center.
Data from these tests guided the design of the full-scale engine, which underwent an additional 700 hours of testing between April and August 2025 to evaluate performance, reliability, and safety under ammonia operation.
Trial results showed low environmental impact, with N₂O emissions around 3 ppm at 100% load and a 95% ammonia co-firing rate, NOx emissions roughly half of those from heavy oil engines, and negligible unburned ammonia. Thermal efficiency in ammonia operation was comparable to or slightly higher than that in heavy fuel oil mode.
J-ENG is also developing a 60 cm bore ammonia engine for larger ships and constructing a new production facility, supported by government funding, to increase capacity for ammonia and heavy fuel oil engines. These developments aim to support the adoption of ammonia as a low-carbon fuel and contribute to reducing greenhouse gas emissions in shipping.
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