29 October 2008. At a ceremony during the recent SMM marine trade show in Hamburg, Germany, MAN Diesel concluded a major order for the first IMO Tier II version of its new 48/60CR four stroke engine with common rail fuel injection - one of the new products exhibited on the company stand. In this way, the engine’s end user, Dover, UK based P&O Ferries is anticipating the 2011 implementation of the second stage of the IMO MARPOL 73/78 Annex VI emissions regulations.
Worth over 35 million Euros, the contract centring on the 48/60CR was signed by Jari Kujala, Purchasing Manager, Aker Yards Oy, Rauma, Finland and Prof. Dr. Wolfram Lausch, Senior Vice President at the MAN Diesel Marine Medium Speed Business Unit. The contract covers the main propulsion and onboard power supply equipment for two large ROPAX ferries being built by Aker Yards for P&O.
On the engine side, for each ship MAN Diesel will supply four inline seven cylinder type 7L48/60CR main engines, each rated 7,600 kW at 500 rpm and four gen-sets based on inline seven cylinder type 7L 21/31 engines, each rated 1463 kWe at 1000 rpm. The scope-of-supply is completed by two double input / single output shaft reduction gears and two controllable pitch propellers per ship. The gears will be supplied by MAN subsidiary Renk AG, Augsburg and the propellers by the MAN Diesel works in Frederikshavn, Denmark.
“P&O has chosen common rail diesels from MAN Diesel due to their inherent reliability and the scope to optimise combustion under all operating conditions and especially at part load,” noted Steve Morant, Project Manager New Build at P&O Ferries, Dover, UK, discussing the background to the contract “This gives us both improved emissions and very useful fuel savings at the present time of high fuel prices.”
As well as the propulsion equipment ordered, for the two ferries, the contract also provides an option for the same scopes-of-supply for two further ROPAX vessels, MAN Diesel stated.
The 48/60CR is the third engine in the MAN Diesel four stroke range to be equipped with common rail fuel injection tech¬nology and at 1200 kW per cylinder, the most powerful. With inline 6, 7, 8 and 9 cylinder and 12, 14, 16 and 18 cylinder vee versions, the 48/60CR’s overall power range of 7,200 to 21,600 kW at 500 or 514 rpm ideally complements the 3,360 to 11,200 kW of the 32/44CR common rail engine announced by MAN Diesel at the 2006 staging of the SMM show.
MAN Diesel Common Rail System.
The MAN Diesel common rail injection system is modular with pressure accumulators subdivided into a series of segments, each serving one or two cylinders. As a result, pressure fluctuations in the system are reduced and rational use made of available space.
On the 48/60CR the solenoid injection control valves are located on the segmented rails and connected to standard, pressure controlled injectors. No servo assistance of injector opening is required. This arrangement keeps sensitive components away from the hot cylinder heads and promotes retrofitting, since identical injectors are used on both the 48/60B and the 48/60CR.
The rails are pressurized by a reduced number of high pressure pumps occupying the same bores as the standard injection pumps and actuated by a modified injection camshaft. The use of at least three high pressure pumps on every engine ensures that emergency operation is possible in the event of the failure of one pump.
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