Experience about & Improvement of DF Engines for LNG-fueled Tugboats

Abstract

Gas engines are attracting worldwide attention amid growing interest in the trends in environmental regulations, as they can clear the IMO's NOx Tier III regulations on their own. However, since gas engine's load response isn't as quick as that of diesel engines in general, they had long been considered to be unsuitable for vessels which require performance expected of diesel engines. In particular, tugboats are regarded as one of the vessels most difficult to operate because they require quick acceleration and rapid load changes. Nevertheless, IHI Power Systems developed the 28AHX-DF dual fuel engine for marine use that can be used as the main engine for tugboats. We created the 28AHX-DF based on technologies we cultivated through the development of land-use gas engines and our experience in engaging in various tugboats equipped with Z-PELLER and diesel engines. In 2015, the 28AHX-DF was installed on Japan's first LNG-fueled tugboat and since then, demand for the engine has been increasing steadily. This paper reports how the load of the 28AHX-DF changed under real operational circumstances and ways to improve load situations.