Technology group Wärtsilä has introduced its NextDF technology for a third engine, the Wärtsilä 46TS-DF dual-fuel engine. While operating on liquefied natural gas, the Wärtsilä 46TS-DF engine with NextDF feature reduces methane emissions to less than 1.4 percent of fuel use across all load points, achieving as low as 1.1 percent in a wide load range. This is nearly three times lower than the default methane slip factor of 3.1 percent, specified in the FuelEU Maritime and IMO Lifecycle Guidelines for Otto-cycle four-stroke dual-fuel engines. Through improvements made to the combustion control, and through optimising engine performance, the new feature also minimises nitrogen oxide (NOx) and CO₂ emissions. emissions.

LNG is an important transition fuel as the marine industry strives to reduce its carbon footprint. However, the main component of LNG is methane and when burned as a fuel, a small amount may not combust properly, leading to methane escaping into the atmosphere. Across the shipping industry, the use of LNG and cutting methane emissions is one of the most effective ways to decrease overall greenhouse gas (GHG) emissions from engines over the next decade, complementing other efforts to reduce CO₂ emissions.

“NextDF technology reduces the environmental impact of vessels that use LNG as fuel, without compromising on performance or operational stability. Importantly, this makes it easier for ship owners to comply with increasingly stringent decarbonisation targets and legislation,” comments Stefan Nysjö, Vice President of Power Supply, Wärtsilä Marine.

Launched in 2022, the Wärtsilä 46TS-DF engine has a two-stage turbocharging to deliver high levels of efficiency and power density across a wide operational range for vessels in all segments of the industry. This level of efficiency reduces fuel consumption and lowers emissions, while being easily retrofittable for sustainable fuels as they become widely available. By applying the NextDF feature, the engine will have the lowest methane emissions and GHG emissions in the 1MW+/cylinder power range.

The Wärtsilä 46TS-DF with NextDF feature was developed as part of the EU co-funded GREEN RAY project*. The initial installation of the Wärtsilä 46TS-DF engine with NextDF feature will be onboard the cruise ship, MSC World Asia, being built by Chantiers de l’Atlantique (CdA) in Saint-Nazaire, France for the Geneva-based cruise operator MSC Cruises.

Nysjö continues: “Owners and operators increasingly need engines with higher efficiency, lower emissions, increased fuel flexibility and lower operating costs. The Wärtsilä 46TS-DF engine already meets these needs, representing a flexible, future-proof solution that can be upgraded in response to sustainable fuel availability. By making our NextDF technology available for the Wärtsilä 46TS-DF engine we enable operators to go even further in lowering GHG emissions and harmful local pollutants.”

The Wärtsilä 46TS-DF engine is the third Wärtsilä dual-fuel engine to be made available with NextDF technology. In 2023 and 2024, Wärtsilä introduced the new technology for its Wärtsilä 31DF and Wärtsilä 25DF engines.