Lower emissions and more power from Bergen C-series engines

www.rolls-royce.com 9 The Bergen C range is available for direct mechanical propulsion or generator set drive. Lower emissions and more power from Bergen C-series engines The latest Clean Design version not only meets IMO NOx targets but its power output has been increased to 330kW per cylinder. R olls-Royce introduced the C-series medium speed diesel engine range in 2002 for direct mechanical propulsion or generator set drive. The 250mm bore, impact of their vessels. At the same time the output of the Bergen C25:33 range has also been Rolls- Royce also offers the Bergen B32:40 range of diesel and lean- burn gas engines extending the 330mm stroke engine was rated at 300kW per increased to 330kW per cylinder at the power range further to over 8MW. cylinder at 1,000rpm. Its design is modular, strong and same revolutions without sacrificing Kjell Harloff, who is deputy VP straightforward for long service and simple maintenance. the engine’s Clean Design capabilities. for offshore engines, expects For example, a cylinder head, liner, water jacket, piston Almost 3,000kW is therefore now that “ by 2009 some 90 per cent and connecting rod can be withdrawn as a unit for available from a compact nine cylinder of the engines we sell will meet servicing without disturbing the big end bearing. engine. the demands of Clean Design A CD version has now been developed. Clean Design This has been done by using classification. Rolls-Royce engines notation requires that NOx in the exhaust gases are advances in turbocharger technology meet this requirement as self- reduced to a minimum of 20 per cent less than the IMO allowing higher pressure ratios, with contained units without requiring permissible limits which apply today. some changes in engine parameters. any space-demanding external “This NOx reduction is achieved without loss of The engine structure had plenty of systems located off the engine.” efficiency, that means the specific fuel consumption is built-in design-stretch to allow for Following the success of the not increased,” says Lutz Liebenberg, Rolls-Royce VP - uprating. Mean piston speed remains gas-fuelled versions of the K and technology and development. “The improvement is a the same at 11m/sec, while the BMEP B-series engines, a gas version result of the application of the Miller cycle in combination is now 24.7 bar, while the specific fuel of the C-series is now under with an increase in compression ratio. To avoid low-load consumption is unchanged at 190g/ development. Gas engines with six, smoke and poor transient load behaviour in the low-load kWh at full load, excluding engine eight and nine cylinders in line will range, which are negative consequences of the Miller driven pumps. be derived from the diesel engine, cycle, the engines are equipped with variable valve A number of uprated C-series with initial deliveries in about two timing (VVT) mechanisms, by which the Miller cycle inlet engines are currently on order, for year’s time. air valve timing may be turned off for low-load running. example seven UT 755 LN supply Article by: Richard White The control of the VVT system is exercised by the engine’s vessels to be built at Cochin shipyard Editorial Consultant. control logic.” in India (see page 16) will each have The Clean Design range has proved very popular as two 6-cylinder C25:33 L6P engines, owners and charterers strive to reduce the environmental delivering 2,000kW per engine.