MAN B&W's New 2 8 / 3 2 A Diesel: Improved Fuel Economy With Same Reliability
MAN B&W Diesel A/S, Alpha Diesel, has introduced an "A" version of their popular medium-speed 28/32 type marine diesel engine which offers a 5 percent improvement in fuel efficiency. Through simple modifications, the new 28/ 32A engine achieved a specific fuel consumption of less than 190 g/kwh (140 g/hph), excellent for its class, while retaining reliability and serviceability. The upgrading was based upon service experiences of the L/V 28/32 engine. MAN B&W Holeby and MAN B&W Alpha supplied about 200 of these engines with an aggregate output of over 330,000 kw (450,000 hp).
Through slight modifications of the engine's combustion chamber and air ducts in the cylinder heads, MAN B&W engineers will be able to enhance the engine's fuel economy. Tests conducted on a six-cylinder L/8232 engine (with a turbocbarger) at the group's Augsburg works showed the engine speed to be 750 rpm; the power per cylinder as 220 kw (300 hp); Bmep as 17.9 bar; maximum combustion pressure as 145 bar; exhaust temperature as 315 degrees C; and Sfoc as 190 g/kwh (140 g/hph).
The test engine results have been confirmed by initial data from the first 6L28/32A production engine on a testbed at Alpha Diesel in Frederikshavn. The moderate brake mean effective pressure and the retention of the original safe engine timing are expected to ensure that the exhaust valve overhaul interval can at least be maintained at—or even extended from—8,000 to 10,000 hours on heavy fuel oil and 12,000 to 18,000 hours on MDO, depending on the operational mode and the fuel specification. The engine is designed for operation on fuels up to 700 cst/50 degrees viscosity.
Demonstrations to potential customers are offered at any power setting up to 1,500 kw (2,000 hp) and at up to 10 percent overload.
The first 28/32A engines have already been delivered to Norwegian and Danish shipowners.
The new 28/32A is available in six, eight and nine-cylinder in-line versions, with a power range of 1,320 kw (1,800 hp) to 1,980 kw (2,700 hp) and in Vee versions with 12 and 16 cylinders, with a range of 2,640- 3,520 kw (3,600-4,800 hp).
For free literature detailing the new 28/32A diesel engine from Alpha Diesel, C i r c l e 4 4 o n Reader S e r v i c e Card