Asia/Pacific News
Japanese Ammonia Engine Completes Testing, Set for Delivery in October
Japan Engine Corporation (J-ENG) has completed the testing of its first commercial ammonia-fuelled engine, with the shipment of the engine to a shipyard scheduled for October.
The 50-bore dual-fuel engine finished trials on August 30 at J-ENG’s factory under the supervision of NYK Line, Nihon Shipyard, Japan Marine United and ClassNK, J-ENG said in a press release on Monday.
The tests confirmed safe and reliable operation in both ammonia and conventional marine fuel modes, with ClassNK certifying its environmental and safety standards.
The achievement builds on extensive testing.
From May 2023 to September 2024, J-ENG ran about 1,000 hours of trials on a single-cylinder ammonia engine at Mitsubishi Heavy Industries’ Nagasaki R&D centre.
Using those results, the full-scale engine began ammonia trials in April 2025, completing a further 700 hours over five months to optimise performance and validate safety systems such as leak prevention and monitoring.
The engine will be installed on an ammonia-fuelled medium gas carrier at JMU’s Ariake shipyard, due to enter service in 2026.
Trials showed over 90% GHG reductions at high ammonia co-firing rates, with virtually zero unburned ammonia emissions.
Ammonia is increasingly seen as a key fuel for decarbonising shipping.
With ammonia engines now becoming commercially available and shipowners beginning to order vessels, the industry is gradually moving to embrace the fuel.
However, significant work remains to develop bunkering infrastructure, as ammonia is toxic and requires strict safety precautions.
J-ENG is also developing a 60-bore ammonia engine variant to power bigger ships.
