J-ENG confirmed the successful completion of trials for its 50-bore dual-fuel engine on August 30 under the supervision of NYK Line, Nihon Shipyard, Japan Marine United and ClassNK.
The engine demonstrated safe and reliable performance on both ammonia and conventional marine fuels, with ClassNK certifying its compliance with environmental and safety standards.
The trials build on more than 1,000 hours of earlier single-cylinder testing at Mitsubishi Heavy Industries’ Nagasaki facility, followed by a further 700 hours of full-scale engine trials since April this year. The system includes safeguards for ammonia leak prevention and monitoring.
The engine will be fitted to an ammonia-fuelled medium gas carrier under construction at Japan Marine United’s Ariake shipyard, scheduled for delivery in 2026.
Tests indicated over 90% greenhouse gas reductions at high ammonia co-firing rates, with negligible unburned ammonia emissions.
J-ENG is also working on a larger 60-bore version to power bigger vessels, as the industry explores ammonia’s potential to decarbonise shipping.
