It says the retrofit solution enables shipowners to reduce the bore size of two-stroke engines by 25% while significantly improving combustion efficiency, which in turn reduces both fuel consumption and greenhouse gas emissions. Wärtsilä says this will improve the efficiency of their existing fleet, ensuring compliance with CII regulations and, it claims, future-proofing assets against future environmental measures.

As a pilot, Wärtsilä 2-Stroke Services installed Wärtsilä Fit4Power on a container ship with a large-bore two-stroke main engine last year.  According to Wärtsilä, the results proved that a vessel with this kind of main engine, that is now oversized for today’s operating patterns, can save 2,000 tonnes of fuel and reduce at least 6,000 tonnes of CO2 emissions annually thanks to this retrofit solution. Fit4Power received certificate of product design assessment from American Bureau of Shipping (ABS) in 2022.

Wärtsilä asserts that, while conventional derating merely tunes engines for operation at lower loads, its system involves reducing the bore diameter of engine cylinders and introducing a new combustion chamber design, enabling the engine to run at optimal loads and with state-of-the-art fuel efficiency. The higher compression ratios and firing pressure achieved mean that the modified engine offers far greater efficiency than either conventionally derated engines or unmodified engines run at much lower loads.

Without modification, according to Wärtsilä, more than 80% of the global merchant fleet could fall into the lowest CII rating by 2030. This would require mandatory corrective action and risking losing business to more efficient vessels. Improving engine efficiency and optimisation with solutions such as Fit4Power is one of the simplest and most cost-effective means of reducing emissions, according to Wärtsilä.

The new solution has been designed to be compatible with Wärtsilä Fit4Fuels (Wärtsilä’s Two-stroke future fuels conversion platform), that enables vessels to use LNG, methanol and ammonia fuels.