MAN Two-Stroke Revision Produces Efficiency Gain

The revision of the G50ME-C9.6 as the G50ME-C10.7 has yielded an extended speed and power layout and reduced specific fuel oil consumption (SFOC) values.

As the Mark 9.6, the diesel is widely favoured for installations in medium-range (MR) tankers, Ultramax and Kamsarmax bulk carriers and other vessels. The new iteration ensures broad market applicability with the added benefit of gains in economy. The optimised fuel efficiency is especially advantageous in the context of existing and upcoming regulations, including the stepwise stricter Energy Efficiency Design Index (EEDI).

At its L1 rating, the existing G50ME-C9.6 provides a 1,720kW output running at 100rpm, giving an MCR range of 8,600-15,480kW across in-line configurations from five to nine cylinders. Down the scale, models chosen at the L4 rating deliver 1,020kW on a crankshaft speed of 79rpm.

The G50ME-C10.7 offers the same top-end 1,720kW per cylinder outturn on 100rpm, but is being released in five- to eight cylinder formats, dispensing with a nine-cylinder unit, while providing L3 and L4 ratings at just 75rpm, slower than that of the Mark 9.6 engine. The elongation of the power diagram is most graphic at the L4 point, where output per cylinder is 970kW at 75rpm.

The Mark 10.7 engine is to be released initially only as a fuel oil burning series. It will be available in Tier II mode with either high-load(HL) optimised or low-load bypass(LL-EGB) matching, or as a Tier III engine with either high-pressure selective catalytic reduction(HP SCR) tuning(where the reactor is fitted upstream of the turbocharger) or with exhaust gas bypass (EGRBP) matching.

Improved SFOC has been achieved for all variants across the load range. For example, in the case of the high-load optimised Tier II engine, the fuel burn at 100% load has been reduced to 164g/kWh from the 167g/kWh of the 9.6 design.

In fact, savings in the order of 3g/kWh are promised throughout. Compared to the 172g/kWh at 100% load of its predecessor, the G50ME-C10.7 in its Tier III version promises 169g/kWh. Similarly, the Tier III HPSCR model of the latest engine is catalogued at 167g/kWh on full load relative to 170g/kWh of the Mark 9.6 type.