Wärtsilä 20 is a compact, lightweight marine engine. It offers fuel flexibility and reliable performance in genset and main engine applications. It is available in diesel and dual-fuel versions, and the dual-fuel version will switch between different fuels during operation smoothly, without power interruption.
Wärtsilä 20 offers outstanding flexibility, which makes it a great choice for generating sets in larger vessels and as a main engine for both mechanical and electric propulsion. The dual-fuel version is a great choice for many vessel types, including hybrid installations.
Ideal applications for the Wärtsilä 20 engine include:
The Wärtsilä 20 has proven its robustness and reliability with over 7500 engines delivered since its introduction to the market in the early 1990s. The engine can switch from MDO to HFO and vice versa without power interruption at any engine operation load.
The engine is available in cylinder configurations 4L, 6L, 8L, 9L with the power output ranging between 740 and 1980 kW at 900, 1000 and 1200 rpm.
The Wärtsilä 20DF is based on the well proven and reliable Wärtsilä 20 diesel engine introduced in the early 1990s. Because of its fuel flexibility, the Wärtsilä 20DF can be optimized for constant speed generating sets, as well as variable speed mechanical drives, for main engine applications.
The engine is available in cylinder configurations 6L, 8L, 9L with the power output ranging between 870 and 1755 kW at 900, 1000 and 1200 rpm.
Get technical data and system proposals for designing marine engine installations with the Wärtsilä 20 and Wärtsilä 20DF.
The Wärtsilä 20 can operate on conventional liquid marine fuels (LFO, HFO or liquid biofuels) or LNG. Fuel switching takes place without loss of power or speed.
For vessel operators, a fuel-flexible engine means that it is possible to comply with the ever-tightening emission regulations. At the same time, operators will have the option to choose fuel according to cost and availability.
Adopting LNG as fuel can help you reduce greenhouse gas emissions significantly. To maximise the environmental benefits of LNG, it is important to minimise methane slip – the unburned methane that escapes into the atmosphere when LNG is burned as fuel.
Wärtsilä 20DF is a great choice because it cuts methane slip in two ways. Its combustion chambers are designed to reduce methane slip, and its combustion controls have been optimised.
Discover the benefits that others have gained from choosing Wärtsilä 20 marine engines.
The MS Helgoland ferry entered a new era of dual-fuel operations with the complete Wärtsilä LNG propulsion solution, featuring two Wärtsilä 20 engines. Watch the video to learn how they adopted a new fuel.
Technology group Wärtsilä will supply the main engines for two new pusher tugs being built for Brazilian operator AMAGGI. The ships are under construction at the Beconal shipyard, located in Manaus, Brazil, and are designed with a focus on decarbonised operations. The engines will run on biodiesel, a capability that was a key factor in securing this contract. The order with Wärtsilä was booked in Q4 2025.
"The fuel flexibility of the Wärtsilä engines will enable these two new pusher vessels to operate using environmentally sustainable biofuels,” says Claudinei Zenatti, Logistics and Operations Director, AMAGGI. “By using biodiesel, these engines are expected to lower total greenhouse gas emissions, supporting both our company’s environmental commitments and the broader goal of delivering more sustainable river transport.”
The ships will each operate with two Wärtsilä 20 engines, equipped with a Wärtsilä Data Collection Unit (WDCU). The engines are able to run on either diesel or biodiesel fuel with a total power output of 2,100kW. This will allow each ship to push as many as 20 barges, carrying a total of 32,000 tons of grain on the Amazon inland waterway system. The Wärtsilä equipment is scheduled for delivery to the yard commencing in August 2026.
“AMAGGI is the first pusher tug operator to run entirely on biodiesel - a step aligned with our shared commitment to decarbonised shipping. The Wärtsilä Data Collection Unit (WDCU) will enable accurate monitoring of the engines, which promotes performance reliability and the benefit of extended overhaul intervals,” explains Genil Mazza, Newbuilding Sales Manager, LatAm – Wärtsilä Marine.
AMAGGI operates a river fleet comprising 212 barges and pusher vessels. Wärtsilä and AMAGGI share a longstanding partnership, having collaborated for more than 30 years to advance sustainable and efficient river transport solutions in Brazil.
Media contact for more information on this release:
Isabella Alder
Positioning and Strategic Communications Manager Wärtsilä Marine
Tel: +44 (0) 7792 681 757
marine.media@wartsila.com
Image caption: Wärtsilä's fuel-flexible engines selected to reduce emissions on two new vessels for Brazilian operator © Wärtsilä Corporation
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Wärtsilä Marine in brief
Wärtsilä Marine is a global pioneer in power, propulsion and lifecycle solutions for the marine market. We develop industry-leading technologies, advancing maritime's transition to new fuels. We support building an end-to-end digital ecosystem where all vessels and ports are connected. Ultimately, Wärtsilä Marine is driving the shipping industry forward on its journey towards a decarbonised and sustainable future through our broad portfolio of engines, propulsion systems, hybrid technology, exhaust treatment, shaft line solutions and digital technologies, as well as integrated powertrain systems. Our offering, which is underpinned by our performance-based agreements, upgrades, lifecycle solutions, decarbonisation services, as well as an unrivalled global network of maritime expertise, delivers the efficiency, reliability, safety, and environmental performance needed to support a safe and sustainable future for our customers, our communities and our planet.
www.wartsila.com/marine
Wärtsilä in brief
Wärtsilä is a global leader in innovative technologies and lifecycle solutions for the marine and energy markets. We emphasise innovation in sustainable technology and services to help our customers continuously improve their environmental and economic performance. Our dedicated and passionate team of 18,300 professionals in more than 230 locations in 77 countries is shaping the decarbonisation of our industries across the globe. In 2024, Wärtsilä’s net sales totalled EUR 6.4 billion. Wärtsilä is listed on Nasdaq Helsinki.
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