RT-flex48T added to two-stroke portfolio

01 Dec 2011
The Wartsila RT-flex48T is started up at QMD in China

The Wartsila RT-flex48T is started up at QMD in China

Wärtsilä reports that its latest six-cylinder Wärtsilä RT-flex48T engine has been successfully started up at the facilities of licensee QMD (Qingdao Qiyao Wärtsilä MHI Linshan Marine Diesel) in China.

The company says that the new engine is the result of further development of the existing RTA48T, and completes the adaptation of the range of low-speed RT-flex engines for all bore sizes. The engine type is available in other cylinder configurations.

The Wärtsilä RT-flex48T is designed to power small bulk and tanker vessels, including the Handysize and Handymax range. With the implementation of the RT-flex common-rail technology, the conventional and familiar RTA48T engine has been upgraded to feature electronically controlled fuel injection and exhaust valve activation for significantly reduced emissions and fuel consumption. One claimed advantage is smokeless operation at all engine load levels.

The key features of the RT-flex common-rail system are precise control of fuel injection, and the high injection pressure at all speeds, which together give steady running. The electronically controlled exhaust valve opening/closing allows optimised engine tuning for each individual engine rating. 

The rail unit and supply unit for the RT-flex48Twere taken from the RT-flex50 type engine. This consists of one common rail pipe for fuel injection and another common rail pipe for the system oil driving the exhaust valves. Both are integrated within the rail unit where all pipe works and components are accessible from above. The rail unit is located just below the cylinder covers along the complete engine length.

"We are extremely pleased to add the Wärtsilä RT-flex48T engine to our portfolio of common-rail low-speed engines. We now have this industry-leading technology available for all bore sizes in our current low-speed engine portfolio," says Martin Wernli, president, Wärtsilä Switzerland and vice president, product centre two-stroke.

Main Data: D-version of Wärtsilä RT-flex48T marine diesel engine

Cylinder bore

480 mm

Piston stroke

2000 mm

Stroke/bore ratio


Power, R1 MCR

1455 kW/cylinder

Speed range, R1-R3

102-127 rev/min

Mean effective pressure at R1

19.0 bar

Mean piston speed at R1

8.5 m/s

Maximum cylinder pressure

160 bar

Number of cylinders

5 - 8

Power range

5100-11,640 kW

BSFC at full-load, R1-R2

164-170 g/kWh

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