Japan Engine Corporation (J-Eng) has received an award for ‘Marine Engineering of the Year (Dokou Memorial Award) 2025’ for its UEC50LSJA ammonia-fuelled low-speed two-stroke engine, from the Japan Institute of Marine Engineering, the Japan Institute of Navigation, and the Japan Society of Naval Architects and Ocean Engineers.
The UEC50LSJA was developed as part of the Next-Generation Ship Development Green Innovation Fund Projects led by New Energy and Industrial Technology Development Organization (NEDO). From May 2023 to September 2024, around 1,000 hours of testing were conducted using a single-cylinder ammonia-fuelled test engine. A full-scale ammonia-fuelled UEC50LSJA engine was manufactured using feedback of result and knowledge obtained from the test engine. Extensive testing totalling approximately 700 hours was conducted over a five-month period starting in April 2025.
According to J-Eng, this engine achieves stable ammonia combustion with a high co-firing ratio through advanced combustion control, while suppressing emissions of nitrous oxide (N2O), a potent greenhouse gas. As a result, GHG emissions are reduced by more than 90% compared with conventional engines. The successful development of this, said to be the first practical ammonia-fuelled low-speed two-stroke engine, contributed to the award.
The engine is scheduled to be installed in an ammonia-fuelled medium gas carrier being constructed by Japan Marine United for Nippon Yusen Kabushiki Kaisha (NYK Line). The vessel is expected to enter service in November 2026. After commissioning, durability and other performance aspects under actual operating conditions will continue to be verified.
Image: The 7UEC50LSJA-HPSCR ammonia-fuelled engine on the test bed (source: J-Eng)
