New Narrow Wärtsilä RT-flex50 D Series

By Keith Henderson at June 12, 2012 07:55
Filed Under: Company News

Wärtsilä has announced the successful testing of a special version of its RT-flex50 two-stroke slow speed series. Designated the D version, it has the turbocharger relocated on the driving end side of the engine. Usually the turbocharger is positioned on the exhaust side of the engine considerably widening it and taking up more valuable engine room space than is really necessary. The new RT-flex50D series is much more compact by locating the turbocharger directly above the fly wheel at the driving end of the engine.


Caption: A typical modern handymax bulk carrier of 52,000 Dwt, MV Sabrina I
Image credit: Nsandel/Wikipaedia

In ships with narrow stern sections the engine choice was limited and often required specifying an engine of smaller bore and higher rotational speed. The reduced width of the new RT-flex50D will allow it to be used in these narrow ship designs and in some cases due to its higher output will allow a reduction in number of cylinders which reduces maintenance costs. The lower rpm of engine and propeller contributes to a beneficial reduction in fuel consumption

The Wärtsilä RT-flex50D is offered in five to eight cylinders configurations in the power range of 6,100 to 13,960 kW with a speed band of 99 to 124 rpm. It has full electronic control of the fuel injection and exhaust valve operation and can operate on a wide range of fuels, from marine diesel oil (MDO) to heavy fuel oil (HFO), of different qualities.

Compared to the existing RT-flex50B series the D series bmep is raised from 20 bar to 21 bar giving a five per cent higher power. The specific fuel consumption is reduced by 1 g/kWh to 170 g/kWh under standard tuning conditions. 

Typical applications for the new D series would be in small bulker and product tankers, handymax and panamax bulk carriers, container and feeder container vessels, and feeder ships.


Caption: A five cylinder Wärtsilä 5RT-flex50D engine on test at licensee
Hyundai Heavy Industries in South Korea. The maximum output of this
engine is 8,725 kW at 124 rpm.
Image credit: Wärtsilä Corp

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