Nippon Yusen Kaisha (NYK) will install a variable compression ratio system (VCR system) on two large LNG-fuelled coal carriers to be built at Oshima Shipbuilding. The vessels are scheduled to be delivered by the end of 2025. This will be the first time for VCR systems to be installed on vessels, including existing vessels that use heavy fuel oil as their main fuel.
The VCR system, developed by Mitsui E&S DU and Winterthur Gas & Diesel, can adjust the air compression ratio in the engine combustion chamber to an optimal balance according to engine power and LNG fuel properties.
This optimal adjustment will improve fuel efficiency during operation by about 3% in LNG gas mode and about 6% in diesel oil mode, according to a release from the Japanese shipping giant.