At a recent ceremony in China, CSSC-MES Diesel (CMD) held the official signing of the contract to construct the first Chinese-built MAN B&W design Green Series 7G80ME-C9.2 engine.
Due for delivery in June 2013, this engine is to be fitted on board a 319,000 dwt, ABS classed VLCC to be built by Shanghai Waigaoqiao Shipbuilding (SWS) for Maran Tankers of Greece.
The G-series engine is hallmarked by its SFOC, energy efficiency and ability to meet all Tier II criteria, MAN claimed.
Qin Wenquan, chairman of CMD, described the 7G80ME-C9.2 engine – rated at 31,150 KW – as “a new, green, marine diesel engine with an ultra-long-stroke and lower speed that follow the design principles of the Mark 9 engine series.
“The G-type engine is a realisation of the most advanced technology, offering advantages in fuel consumption, exhaust emission and energy efficiency,” he said.
Goetz Kassing, managing director of MAN Diesel & Turbo, China praised the co-operation between CMD, MAN Diesel & Turbo, Shanghai Waigaoqiao and Maran Tankers and affirmed his company’s strong belief in building engines, as close as possible to ship construction sites.
He called CMD “a highly reputable engine builder” and portrayed the company’s recent success as a clear sign of its competitiveness in today’s international market.
CMD Chairman Qin Wenquan also compared the MAN B&W 7S80ME-C9.2 engine and a G80 engine installed on board a 319,000 dwt VLCC, where the G80 engine has a greater efficiency of 1%.
Assuming optimum running conditions, including an optimum propeller set-up, propeller efficiency can be improved by about 3.6%. Under the same ship-speed conditions, overall running costs can accordingly be reduced by 4.6%, a significant saving that MAN Diesel & Turbo figures suggest can even be bettered, depending on individual circumstances.
Again, under the same ship-speed conditions, the EEDI would be reduced by some 8.2% when using the G80 as opposed to S80 engine. Qin Wenquan concluded that the G80ME-C9.2 engine fulfils the demands of high efficiency ships, ensuring that it will eventually become the natural choice for VLCC vessels.
Goetz Kassing backed this analysis up, observing that the G80’s longer stroke results in a lower rev/min for the engine driving the propeller: a reduction from 78 rev/min for the S80 engine to 68 rev/min for the G80.
He further noted that the lower optimum engine speed allows for the use of a larger propeller. This, ultimately, is significantly more efficient in terms of engine propulsion and, together with an optimised engine design, reduces fuel consumption and reduces CO2 emissions.
The G-type programme was introduced in October 2010 with the entry of the G80ME-C9 model. MAN Diesel & Turbo subsequently expanded the ultra-long-stroke programme in May 2011 with the addition of G70ME-C9, G60ME-C9 and G50ME-B9 models.
The G-types have designs that follow the principles of the large-bore, Mark 9 engine series that MAN Diesel & Turbo introduced in 2006.
Their longer stroke reduces engine speed, thereby paving the way for ship designs with unprecedented high-efficiency, MAN claimed.