The Nikkei reports that Mitsubishi Heavy Industries Ltd. (MHI) will unveil by 2015 its own natural-gas-powered marine engine. MHI reportedly improved existing technology to develop a combustion engine that efficiently burns high-pressure gas through direct injection.
In addition to reducing CO2 emissions by some 30% compared to the diesel-fueled engines MHI currently offers, the new engine also cuts sulfur oxide emissions effectively to zero. The engine will be marketed to customers after emissions levels and fuel economy are tested through a trial run that starts in late 2013 at Mitsubishi Heavy’s Kobe shipyard, according to the report.
The engine will be used for liquefied natural gas (LNG) carriers, large tankers and container ships.
Earlier this year, MHI introduced Japan’s first system for supplying high-pressure gas that will enable use of natural gas as fuel for marine engines. MHI agreed with Mitsui Engineering & Shipbuilding Co., Ltd. (MES) for delivery of the first unit.
MHI’s new high-pressure gas supply system delivers LNG at 30 megapascals (MPa) gas by liquid pumping, and it is characterized by its compact configuration and less power consumption. An hydraulic driver is adopted for the liquid pump without a speed reduction mechanism, which facilitates variable speed adjustment and high flexibility of layout.
The company commercialized the system leveraging its broad technological base and R&D achievements not only in cryogenics field backed with long experience of building of LNG carriers, but also in the area of marine engine field, general machinery and sealing.
The system consists mainly of a unit to transfer LNG at high pressure according to fluctuations in the demand of the engine, an hydraulic unit as power source, a unit to produce a compressed natural gas (CNG) by heating LNG to normal temperature, a CNG bottle unit to buffer the CNG pressure variation and gas combustion unit to safely dispose low pressure off-gas and to use its exhaust heat as heat source.