Swiss engine designer WinGD has completed both type approval testing and factory acceptance testing for its X52DF-A-1.0 two-stroke engine, in what the company describes as a first for an ammonia-fuelled two-stroke marine engine.
The tests were carried out in January at HD Hyundai Heavy Industries’ Engine & Machinery facility in South Korea. The programme was witnessed by Lloyd’s Register, alongside representatives from other classification societies, and supervised by Belgian shipowner EXMAR. The 52-bore engine is due to be installed on a 46,000 cubic metre LPG and ammonia carrier on order for EXMAR. The vessels in the series are expected to become the first ammonia-fuelled gas carriers to enter commercial service.
For shipowners assessing alternative fuels, the completion of both approval stages reduces a key technology risk: type approval confirms compliance with classification requirements, while factory acceptance testing validates performance prior to installation.
Sotiris Topaloglou, Global Head of Testing and Validation at WinGD, said: ‘Completing Type Approval Testing and Factory Acceptance Testing with our joint development partner HHI-EMD represents a major technical milestone in the development of ammonia-fueled two-stroke propulsion. As first movers, we are addressing a completely new fuel landscape, where safety, control and system integration are paramount. We have developed an engine that has been well proven to be safe and efficient by tackling, one by one, all the technical challenges we faced.’
The X-DF-A platform uses high-pressure ammonia injection, supported by a pilot fuel dose of around 5 per cent at full load. According to the WinGD, the engine delivers load handling and fuel efficiency comparable to equivalent diesel-fuelled engines in both ammonia and diesel modes. Emissions data indicate nitrogen oxide levels during ammonia operation well below those recorded in diesel mode, while nitrous oxide emissions were measured at very low levels.
Kristof Coppé, Director Fleet Operations and Technical Business Development at EXMAR, said: ‘These successful tests represent a key milestone in EXMAR’s development of ammonia as a marine fuel, a journey that began in 2021. Drawing on more than 40 years of experience in transporting ammonia as cargo, EXMAR has been able to critically assess both the engine design and the test program, with particular attention to the safety considerations associated with using a toxic cargo as fuel.
‘EXMAR now looks ahead to the next phase, which will involve sea trials on ammonia fuel. These trials will have to validate the seamless integration and performance of all onboard systems. Preparations are currently underway, with the trials scheduled to take place in the coming months.’
WinGD reports an early orderbook of around 30 X-DF-A engines across gas carriers, bulk carriers, tankers and container vessels, indicating interest beyond the gas carrier segment. Sea trials will provide the next operational test as the first engines approach installation. Performance in service will determine how quickly ammonia propulsion moves from controlled testing to wider commercial deployment.
