Japan Engine Corporation (J-ENG) has already attracted a world-first fully-functional ammonia-powered engine, and it is a breakthrough in decarbonization efforts of marine transportation. The 7UEC50LSJA-HPSCR demonstrated over 90% greenhouse gas emissions per test cycle between August 27 and 30, 2025, under the directive of major shipping industry stakeholders. This is an important milestone that can be hugely significant in achieving the objective of achieving carbon neutrality of the world shipping industry by the year 2050.
Historic engine testing achieves remarkable environmental performance
According to J-ENG, Hiroshima Engine Corporation detailed the first demonstration of a fully functioning full-scale commercial engine 7UEC50LSJA-HPSCR on August 30, 2025, and is being developed as part of Next-Generation Ship Development of the Green Innovation Fund Project administered by the New Energy and Industrial Technology Development Organization (NEDO). Between August 27 and 30, 2025, at the factory of J-ENG, the engine’s official test run was conducted, supervised by Nippon Yusen Kaisya (NYK Line), Nihon Shipyard Co., Ltd. (NSY), Japan Marine United Corporation (JMU), and Nippon Kaiji Kyokai (ClassNK).
It passed through a battery of performance verification tests in both ammonia fuel operation mode and heavy fuel oil operation mode as a dual-fuel engine and post-operation tests of key members, which certified the outstanding performance of the engine and the safety specifications in the environmental context, which had been approved by ClassNK. Preliminary data on this engine indicates that at full load and a co-firing rate of 95% ammonia, the text rates at 100% load are around 3ppm, which represents a reduction of more than 90% in greenhouse emissions.
Engine scheduled for commercial deployment in 2026. This engine will be delivered in October 2025 and put on an AFMGC (Ammonia-Fueled Medium Gas Carrier) under construction by JMU Ariake Shipyard. It will be launched into service in 2026, the first commercial use of ammonia propulsion in the marine industry.
Extensive development program spans multiple testing phases
Already, J-ENG had done about 1,000 hours of ammonia-fuel test engine test runs on a 1-cylinder ammonia-fuel test engine at the Mitsubishi Heavy Industries Research and Development Center in Nagasaki between May 2023 and September 2024, Fuel Cells Works reports. Based on the findings and knowledge acquired during the test, J-ENG produced the first full-scale commercial engine, 7UEC50LSJA-HPSCR, and started to undergo test performances with ammonia fuel in April 2025.
Nitrogen oxide emissions were reduced by half compared to conventional engines
Emission of nitrogen oxide (NOx) was ascertained to be about half of that of heavy oil engines, with the amount of incompletely burned ammonia as well near zero (post-NOx SCR). Those further to check have reported that the thermal efficiency of the ammonia fuel operation mode is equal to or greater than the heavy oil operation mode, indicating better performance metrics have been achieved in the same on various levels.
Future expansion plans target global market adoption
Based on the above-mentioned (bore 50cm) first engine, J-ENG is also simultaneously developing an ammonia-fueled engine with a 60cm bore to suit the wide range of ammonia-fueled ships that will appear in the future market. They are actually in the process of developing several promising follow-on projects. Moreover, once the development and social application of these engines were concluded, J-ENG is now undertaking the creation of a brand new factory with a government-sponsored project done through GX Economic Transition Bonds.
Japan Engine Corporation’s breakthrough is a key milestone in the shift in the development of the maritime sector, demonstrating that ammonia propulsion can be beneficial to the environment, in addition to being a practically effective solution and operationally compatible. As the pioneer in the next-generation fuel engines, J-ENG will be at the forefront of the use of sustainable shipping solutions around the world.