This page contains a Flash digital edition of a book.
The engineroom aboard one of the first three Q-Flex LNG carriers.


S50ME-B9 stokes fuel economy


turbochargers throughout the world, of which 17 are licensed manufacturers for two- stroke engines; in China, Japan, South Korea, Vietnam, Russia, Poland, and Croatia. Te latest two-stroke licensee contract, signed in January, is with Zhenjiang CME Co Ltd (ZJCME), a Chinese engine manufacturer and subsidiary of CSSC, for engines up to 50cm bore. Seven of MAN Diesel’s licensees for two-stroke engines are based in China. In August 2007, an agreement with Wuxi Antai Power Machinery Co Ltd was signed for small- to medium-bore two-stroke engines. Earlier last year MAN B&W additionally signed a licence contract with CSSC-MES Diesel Co Ltd, located near Shanghai. MAN Diesel’s two-stroke MC engine


programme has evolved to embrace bore sizes from 260mm to 980mm, and even 1080mm – which is not yet in production. In January, Polish licensee H. Cegielski - Poznan SA tested its first electronically-controlled MAN B&W ME-C7 engine, which will be installed as the main engine in a series of car and truck carriers ordered by Ray Car Carriers Ltd of Douglas, Isle of Man. In December 2007, meanwhile, the


first MAN B&W S40ME-B9 low-speed small-bore engine was built by STX Heavy Industries Co Ltd, South Korea. Te ME-B design is based on the experience from the popular MC-C and ME-C engines. To suit the small-bore segment, the economical ME-B design utilises a camshaſt-operated exhaust valve and an electronically- controlled fuel-injection system, as seen


The Naval Architect April 2008


with the ME-C range. To achieve the lowest possible propeller revolutions in relation to bore size, the new ME-B9 engine has a stroke/bore ratio of 4.4. Tis has been achieved by increasing maximum cylinder pressure, resulting in improved fuel consumption that is 2g/kWh lower than existing, small-bore engines. In early 2007 MAN Diesel launched


the S50ME-B9 engine design. The ME-B programme now has an output range from 2975kW to 16,020kW and the market reception has been very positive to date, with more than 60 orders placed. Te two-stroke S50ME-B8 engines being


built by DMD Dalian Marine Diesel for seven chemical/product tankers on behalf of Torm Group are the first engines fitted with TCA66 turbochargers with variable nozzle rings technology (VTA). Another milestone was reached in LNG


carrier propulsion in September last year, with the successful conclusion of testing for the first two-stroke propulsion engines to be installed aboard three of Qatargas’ 45 newbuildings, in the form of a pair of 6S70ME-C or 7S70ME- C7 electronically-controlled, two-stroke, low-speed diesel engines. Tese engines will operate on heavy fuel oil, but MAN B&W is also promoting its range of dual-fuel ME-GI engines, containing a high-pressure injection system of natural gas. Te engine programme also includes the


51/60DF dual-fuel medium-speed engine, which is targeted at LNG carriers with a diesel electric-propulsion configuration.NA


The sterns of merchant vessels are often redesigned to accommodate bigger propellers with higher efficiency and lower optimum speed (rev/min). Today, the optimum propeller speed of large Handymax or small Panamax bulk carriers and tankers is often lower than the nominal 127rev/min figure quoted for an S50MC-C7 engine, and higher than the equivalent 105rev/min value for the next bore up, the S60MC-C7. Accordingly, the optimum main engine may be one with an SMCR (specified maximum continuous rating) speed within this 105rev/min-127rev/min range. The new S50ME-B9 engine from


MAN Diesel is a competitive alternative with a nominal MCR speed of 117rev/min. The engine adopts the design features introduced by the smaller ME-B9 engines with their MEP (mean effective pressure) of 21bar and stroke/bore ratio of 4.4. Fuel savings achieved through the


installation of a propeller with lower revolutions are dependent on the propeller diameter - the bigger the better - and on the corresponding lowest optimum propeller speed. The influence on propulsion power necessary to maintain ship speed can be expressed by means of the constant ship speed factor, a


p2 = p1 × (n2/n1)a


where p = propulsion power; n = propeller speed. In situations where optimum SMCR


speed is ≤ 117rev/min, MAN Diesel says it might thus be advantageous to install an S50ME-B9 engine. A MAN Diesel study shows that fuel savings could be of the order of 5%-6%.


19


Feature 1


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72