J-ENG completes trials of ammonia-capable engine
Engine manufacturer Japan Engine Corporation (J-ENG) has successfully completed testing of its newly developed ammonia-capable 50-bore dual-fuel engine.
IMAGE: J-ENG’s ammonia-capable engine. J-ENG
The official trials, conducted in August under the supervision of Nippon Yusen Kaisha (NYK Line), Nihon Shipyard (NSY), Japan Marine United (JMU) and classification society ClassNK, verified the engine’s performance in both ammonia and heavy fuel oil operating modes.
Before developing the full-scale model, J-ENG had carried out around 1,000 hours of trials on a single-cylinder ammonia-fuel test engine at Mitsubishi Heavy Industries’ R&D Center in Nagasaki between May 2023 and September 2024.
Drawing on those results, the company built its first commercial-scale engine, beginning ammonia-fuel test runs in April 2025. Over the following five months, the engine underwent a further 700 hours of testing.
According to trial data, the engine achieved more than a 90% reduction in greenhouse gas (GHG) emissions at 100% load with a 95% ammonia co-firing rate. An engine's co-firing rate refers to the ratio between the energies supplied by two different fuels, typically including a renewable fuel.
The unit is scheduled for shipment in October 2025 and will be installed on an ammonia-capable medium gas carrier under construction at JMU’s Ariake Shipyard. The vessel is expected to enter service in 2026.
In parallel, J-ENG is also developing a larger 60-bore ammonia-capable engine designed to power bigger vessels.
By Tuhin Roy
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