First Ammonia Dual-Fuel Large Low-Speed Engine Inspected by China Classification Society Successfully Delivered

Ammonia fueled low-speed marine diesel engineRecently, the first ammonia dual-fuel large low-speed engine inspected by the China Classification Society (CCS) successfully completed its bench test and was delivered at the Zhuhai factory of Yuchai Marine Power Co., Ltd. This marks a major breakthrough in China’s development of marine ammonia-fuel low-speed engines, advancing from technical verification to engineering and commercial delivery. It also represents another solid step forward for CCS in the development of green energy power inspection technologies.

The engine was independently developed by CSSC WinGD Co., Ltd., a subsidiary of China State Shipbuilding Corporation Limited (CSSC). The model is 6X52DF-A-1.0, with a cylinder bore of 520 mm and a rated power of 7,470 kW. The engine adopts high-pressure liquid ammonia direct injection technology, allowing flexible switching between ammonia fuel and diesel modes, with power performance comparable to traditional diesel engines. Equipped with a high-pressure SCR exhaust after-treatment system, it meets IMO Tier III emission standards and achieves zero carbon dioxide emissions when operating in ammonia fuel mode. The engine has been fully validated by CCS and will be installed on a 25,000 m³ LPG/ammonia carrier owned by Tianjin Southwest Maritime Co., Ltd., which is classed solely with CCS.

During the project’s progress, CCS formed a dedicated service team to provide ongoing support, offering strong technical assistance in areas such as technical preparation, certification planning, drawing review, component inspection, and on-site test verification. The team worked closely with all parties to effectively coordinate and achieve key technological breakthroughs. CCS Guangzhou Branch surveyors visited Zhuhai Yuchai, Huangpu Wenchong, and other units multiple times to carry out technical coordination and exchanges. They participated throughout the entire process of technical verification, performance evaluation, and type approval testing, comprehensively examining the engine’s safety, operability, reliability, and stability. The surveyors confirmed that all test items were successfully completed and that core indicators reached world-leading levels, providing solid assurance for the smooth delivery of the engine.