Ammonia-fueled two-stroke engine passes second FAT

May 21, 2026, by Nadja Skopljak

Following what was described as the world’s first type approval (TAT) and factory acceptance testing (FAT) for this type of engine some three months ago, Swiss marine power company WinGD has completed another FAT for its ammonia-fueled two-stroke marine engine.

Built by Yuchai Marine Power (YCMP), the X52DF-A-1.0 engine underwent testing in April, in the presence of China Classification Society.

This latest FAT follows the completion of TAT and the first FAT of the ammonia-fueled engine platform at the HD Hyundai Heavy Industries’ Engine & Machinery (HHI-EMD) facility in South Korea, as announced in February.

According to WinGD, the testing took place on the 52-bore engine to be installed on a 25,000m3 LPG/ammonia carrier and demonstrated stable engine performance and encouraging emissions results. NOx emissions during ammonia operation were significantly lower than those from conventional fuels, while N2O emissions remained minimal, contributing to an improved overall greenhouse gas profile.

The engine will be installed on the first vessel for Tianjin Southwest Maritime in a series of four LPG/ammonia carriers currently under construction at CSSC Huangpu Wenchong Shipbuilding in China.

“The successful completion of Factory Acceptance Testing in China provides further validation of our X-DF-A platform across key performance and safety parameters. The results demonstrate continued progress in the development and validation of ammonia-fuelled engine technology,” said Peter Krähenbühl, VP Product Center at WinGD.

“Bringing ammonia propulsion into commercial service depends on close cooperation across the maritime value chain, particularly between engine designers and engine builders. Working closely with partners such as YCMP allows us to translate development progress into reliable manufacturing and testing outcomes, supporting the safe and efficient deployment of ammonia-fuelled propulsion technologies.”