Market demands longer stroke, says MAN

01 Jun 2011
Ole Grøne: “ The G-type engines will optimise propulsion efficiency:

Ole Grøne: “ The G-type engines will optimise propulsion efficiency:

Following the introduction of its G80ME-C9 engine in October 2010, MAN Diesel & 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 MEC9 and G50ME-B9 engines. The G-types use designs that follow the principles of the large-bore Mk-9 engine series that MAN Diesel & Turbo introduced in 2006. The longer stroke reduces engine speed, which the company says paves the way for higher-efficiency ship designs.

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 & Turbo 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 increasingly being specified with S80ME-C9 and S90MEC8/9 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.

MAN says that 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. It is estimated that such new designs offer potential fuel-consumption savings of some 4-7%, 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.

Ole Grøne, senior vice president low-speed sales and promotions said: “MAN Diesel & Turbo always follows developments in the shipping market closely and we have kept a close eye on the trend for fuel optimisation in recent years. As such, we have experienced great interest in the G-type engine during extensive consultation with industry partners and are currently working on a variety of projects with shipyards and major shipping lines. As a result, we have reached the conclusion that the introduction of the G-type engine programme is both viable and timely. The speed and power of these G-type engines have been carefully evaluated with a view to optimising propulsion efficiency while, at the same time, facilitating their adoption by shipyards.”

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.

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