MARINESHELF publishes articles contributed by seafarers and other marine related sites solely for the benefit of seafarers .All copyright materials are owned by its respective authors or publishers.

BENEFITS

FROM

THE

SULZER

RT-FLEX

SYSTEM

At its heart, the Sulzer RT-flex engine is the same reliable,

basic engine as the existing RTA engine series. The power

ranges, speeds, layout fields and full-power fuel

engine

consumptions are the same for both engine versions.

The Sulzer RT-flex engine offers a number of

standard for Sulzer RTA-series engines. For this reason, the

interesting benefits to shipowners and operators:

RT-flex system incorporates certain design features not

• Reduced running costs through lower part-load fuel

seen in other common-rail engines using middle-distillate

consumption and eventually longer times between

diesel oils. The key point is that, in the RT-flex system, the

overhauls

heated heavy fuel oil is kept away from the precision

• Reduced maintenance requirements, with simpler

quick-acting rail valves.

setting of the engine, for example adjustment of

The key features of the Sulzer common-rail system are

mechanical injection pumps is no longer necessary, and

thus:

‘as-new’ running settings are automatically maintained

• Precise volumetric control of fuel injection, with

• More balanced engine operation. The common-rail

integrated flow-out security

system with volumetric control gives excellent balance

• Variable injection rate shaping and variable injection

in engine power developed between cylinders and

pressure

between cycles, with precise injection timing and

• Possibility for independent action and shutting off of

equalised thermal loads

individual fuel injection valves

• More predictable maintenance costs owing to better

• Ideally suited for heavy fuel oil

balanced engine operation and better retaining of

• Well-proven standard fuel injection valves

engine settings over many running hours

• Proven, high-efficiency common-rail pumps

• Extendable times between overhauls through better

• Lower levels of vibration and internal forces and

engine running conditions, and better prediction of

moments

maintenance timing

• Steady operation at very low running speeds with

• Better fuel economy in actual in-service load range

precise speed regulation

• Flexibility to optimise fuel consumption at selected

• Smokeless operation at all speeds.

service loads within compliance with the NOX

emission

limit in Annex VI of the MARPOL 73/78 convention

The RT-flex system encompasses more than the fuel

• Smokeless operation at all operating speeds.

injection process. It includes exhaust valve actuation and

• The RT-flex system is based on well-proven hardware

starting air control. The exhaust valves are operated in

• Full electronic common-rail control with integrated

much the same way as in existing Sulzer RTA engines by a

monitoring functions

hydraulic pushrod but with the actuating energy now

• Lower steady running speeds, in range of 10–12 rev/

coming from a servo oil rail at 200 bar pressure. The servo

min obtained smokelessly through sequential shut-off

oil is supplied by high-pressure hydraulic pumps

of injectors in all cylinders. Selective shut off of

incorporated in the supply unit with the fuel supply

injectors gives more balanced engine operation than

pumps. The electronically-controlled actuating unit for

cutting out cylinders

each cylinder gives full flexibility for valve opening and

• Built-in overload protection

closing patterns. This unit utilises exactly the same Sulzer

• Built-in redundancy, as 100 per cent power can be

rail valves as are used for controlling fuel injection.

developed using three of the four fuel pumps, and with

All functions in the RT-flex system are controlled and

one servo oil pump out of action.

monitored through the integrated Wärtsilä WECS-9500

electronic control system. This is a modular system with

Shipowners are becoming very interested in RT-flex

separate microprocessor control units for each cylinder,

engines, and already orders have so far been booked for six

and overall control and supervision by duplicated

engines, including the one in the

Gypsum Centennial

.