Overview

• Japan Engine Corporation completed official factory tests of its 7UEC50LSJA-HPSCR engine on August 30 under supervision by NYK, NSY, JMU, and ClassNK, which certified its environmental performance and safety.
• The full-scale, seven‑cylinder, 50 cm‑bore unit is a dual‑fuel design that can run on ammonia or heavy fuel oil and incorporates high‑pressure SCR aftertreatment.
• Company trial data report about 3 ppm N2O at 100% load with 95% ammonia co‑firing, more than a 90% cut in GHGs, roughly half the NOx of oil engines, and near‑zero unburned ammonia after SCR, with thermal efficiency at least on par with oil mode.
• Development drew on about 1,000 hours of single‑cylinder testing (May 2023–Sep 2024) and roughly 700 hours on the full‑scale engine (Apr–Aug 2025) with a focus on combustion, leak prevention, and ammonia safety monitoring.
• The engine is slated to ship in October 2025 for installation on an ammonia‑fueled medium gas carrier under construction at JMU Ariake, as J‑ENG also advances a 60 cm‑bore model and a new factory planned to start in fiscal 2028 with government support.