MAN optimises engines for low SFOC at Tier II limits

08 Sep 2010
MAN B&W low speed engines can be optimised for lower SFOC at IMO Tier II limits

MAN B&W low speed engines can be optimised for lower SFOC at IMO Tier II limits

MAN Diesel told 'The Motorship' at SMM that it has been looking at its entire MAN B&W low speed engine programme in respect of the IMO Tier 2 limits.

This follows the so-called ‘Tier 2 optimisation programme’ initiated earlier in 2010 for a limited number of two-stroke engines. The company has now concluded that it will be possible to achieve the required NOx reduction without increasing fuel consumption – in fact for a number of engines the SFOC can actually be reduced by 1-2 g/kWh.

The company says that the first phase of development saw an increase in SFOC of up to 6g/kWh for the MC and MC-C engines, while, thanks to the more flexible electronic control of fuel injection and exhaust valve, the fuel consumption penalty for the ME engines was around 4g/kWh.

By implementing a number of measures, including increased scavenge air pressure, lower compression ratio with two-stroke Miller timing, increased maximum compression pressure and adjustments of compression volume, the SFOC penalty has been eliminated.

The Tier 2 versions of the engines will be recognised by an additional number following the type designation, e.g. where S80ME-C8/9 is the Tier 1 engine, the normal Tier 2 version will be known as the S80ME-C8.1/9.1, and the fuel optimised version as the S80ME-C8.2/9.2.

The company is now setting its sights on optimising the low speed range for Tier 2 compliance at low load operation, using technologies including exhaust gas bypass, variable turbine area (VTA) turbocharging, part-load tuning (for electronic engines) and turbocharger cut-out.

Links to related companies and recent articles ...

MAN Diesel A/S

view more