Turbocharger variations for low load

For some operators, ships are run continuously at reduced speeds, while others require the full speed range to be maintained. Wärtsilä says that its solutions offer this flexibility, and can be tailored to individual operating patterns to provide maximum fuel efficiency, engine reliability, and reduced CO₂ emissions.

The automated flexible turbocharger cut-out – also known as the slow steaming upgrade kit – extends the load range of the engine for continuous economical low load operation, by cutting-out one of the turbochargers, which leads to increased scavenge air and thus firing pressures.

In addition to reducing BSFC in the low-load range, this solution provides full flexibility (the engine can be operated from 10 to 100%) and decreases the risk of engine fouling and excessive component temperatures. This retrofit is available for ships with Wärtsilä RTA and RT-flex low-speed engines with more than one turbocharger.

If the operational profile of a vessel requires slow steaming for a longer period, and engines are not needed to operate above 60%-70% load, blinding of one of the turbochargers is the most cost effective solution. The disadvantage is that the engine load range is limited and full speed running is no longer possible, but the turbochargers can be reinstated to original with reasonable time and cost.

The turbocharger solutions can be further optimised by engine derating and/or propeller modifications.