Following the introduction of its G80ME-C9 engine in October 2010, MAN Diesel and Turbo has announced the addition of further bore sizes to its ultra-long-stroke engine programme. The updated engine programme has supplemented the original G-type engine with G70ME-C9, G60 ME-C9 and G50ME-B9 engines.
The G-types have designs that follow the principles of the large-bore Mk-9 engine series that MAN Diesel and Turbo introduced in 2006. Their longer stroke reduces engine speed, and MAN believes this will pave the way for ship designs with unprecedented high-efficiency.
Tankers and bulk carriers have traditionally used MAN B&W S-type engines with their long stroke and low engine-speed as prime-movers, while larger container vessels have tended to use the shorter-stroke K-type with its higher engine speed.
Following efficiency optimisation trends in the market, MAN Diesel and Turbo has also thoroughly evaluated the possibility of using even larger propellers and thereby engines with even lower speeds for the propulsion of tankers and bulk carriers. Larger container vessels are now increasingly being specified with S80ME-C9 and S90ME-C8/9 engines because of the opportunity they offer to employ larger propeller diameters; an S90ME-C9 engine will replace a corresponding K98 with the same cylinder count.
Such vessels may be compatible with propellers with larger diameters than current designs, and facilitate higher efficiencies following adaptation of the aft-hull design to accommodate a larger propeller. MAN estimates that such new designs offer potential fuel-consumption savings of some four to seven percent, and a similar reduction in CO2 emissions.
Simultaneously, the engine itself can achieve a high thermal efficiency using the latest engine process parameters and design features.
MAN said the final drawings for the structure, moving parts and fuel equipment of the first G-type – the G80ME-C9 – are scheduled for delivery by mid-2011 with piping and gallery drawings scheduled to follow in the latter part of 2011, depending on order dates.