Wärtsilä 25 engine offers fuel flexibility

By Becky Schultz12 September 2022

Wärtsilä 25 marine engine The Wärtsilä 25 is capable of operating on diesel, LNG or gas or liquid carbon-neutral biofuels, plus can be upgraded to operate with future carbon-free fuels. (Photo: Wärtsilä)

The newly launched Wärtsilä 25 medium-speed, four-stroke marine engine features a modular technology platform that gives shipowners and operators maximum flexibility while delivering enhanced efficiency, greater fuel economy and minimized emissions. It is suitable for mechanical, diesel-electric and hybrid installations.

The engine is capable of operating on diesel, LNG or either gas or liquid carbon-neutral biofuels, plus can be easily upgraded to operate with future carbon-free fuels as they become available, said Wärtsilä. Technology development is currently underway for the engine to become the company’s first model to run on ammonia as a fuel. Technology concept readiness is slated for 2023, followed by a planned product release shortly after.

“This engine marks the beginning of a new era of future-proof medium-speed, small bore engines, and comes as an important step towards the maritime industry meeting its decarbonization goals,” stated Roger Holm, president, Marine Power, and executive vice president, Wärtsilä Corporation. “It is a small but powerful engine, and it provides an effortless transition to future fuels, making it a future-proof investment already today.”

The new model is currently available in 6 L, 7 L, 8 L and 9 L cylinder configurations (250 x 350 mm bore x stroke) featuring a robust and efficient turbocharging system with a high pressure ratio. The dual-fuel (DF) version has power output ranging from 1.9 to 3.1 MW, while the diesel version has output from 2.0 to 3.4 MW. Common rail high-pressure fuel injection technology optimizes combustion and the fuel injection settings at all loads, promoting smoke-free operation.

Other features include a self-learning proportional, integral, derivative (PID) control to reduce calibration needs, and the Wärtsilä Expert Insight service for gathering critical engine data for predictive maintenance, reporting and analysis purposes. Modules can be replaced “on the fly,” which eliminates the need for separate software downloads. Optional adjustments for arctic or tropical conditions and for reducing emissions to the level of a pure gas engine are also available.

The engine supports dry docking schedules with a time-between-overhauls (TBO) of up to 32,000 hours, meaning both downtime and operating costs are significantly reduced, the company asserted. Data-driven dynamic maintenance planning and predictive maintenance services can extend the TBO even further.

When operating with natural gas, the engine is IMO Tier III compliant; it is also compliant with diesel fuel when integrated with the company’s NOx Reducer (NOR) emissions abatement system. In addition, the engine complies with regulations such as the IMO CII and EEXI protocols going into effect in 2023.

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