Wärtsilä 31

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Wärtsilä 31 - the world’s most efficient 4-stroke engine

The Wärtsilä 31 is a medium-speed 4-stroke marine engine that is designed to set a new benchmark in efficiency and overall emissions performance. Available in cylinder configurations from 8 to 16 and with a power output ranging from 4.6 to 10.4 MW at 720 and 750 rpm, the Wärtsilä 31 provides the best fuel economy of any engine in its class. At the same time, it maintains outstanding performance across the complete operating range. Its high-power output per cylinder helps you save space and the extended service interval together with high up-time helps you save in maintenance. The engine is available in diesel, dual fuel and pure gas versions.

Wärtsilä 31 is recognised by Guinness World Records as the world's most efficient 4-stroke diesel engine.

Key benefits

The Wärtsilä 31 retains its high efficiency and environmental values throughout the entire lifecycle of the vessel.

  • Lowest fuel consumption over its wide operating range
  • Remarkably high cylinder power, 650 kW/cylinder (diesel engine)
  • Meets the IMO Tier 3 regulations when operating on gas, and with a SCR when using diesel fuel
  • Proven and reliable – running since 2018
  • Industry-leading lifecycle support maximising predictability and minimising costs

Who is it for?

Wärtsilä 31 is a perfect solution for ferries where operational flexibility, high power density, long intervals between overhauls, and high levels of safety are of paramount importance. Also fishing vessel and luxury cruise ship owners appreciate the Wärtsilä 31’s low noise emissions. The Wärtsilä 31 is designed to be suitable for a broad range of ship types and applications, in diesel electric configurations or as an auxiliary engine. And as the engine is available in diesel, dual fuel and pure gas versions you can easily choose a configuration that matches your requirements. 

Wärtsilä 31 and Wärtsilä 31DF Product guide and 3D models and drawings

Get technical data and system proposals for designing W31 and W31DF marine engine installations.

Wärtsilä 31 engine

Customer stories

Discover the benefits others have already gained from Wärtsilä 31 engine.

  • Le Commandant Charcot

    Le Commandant Charcot, the world’s only luxury icebreaker, uses the Wärtsilä 31DF engines for sustainable polar exploration

    Read more about Wärtsilä 31DF engine with hybrid operation
  • Hammershus slide banner

    The first Wärtsilä 31 engines now in daily commercial operation

    Read more
  • Fishing-vessel-for-Peter-Hepsø-Rederi-AS
    Peter Hepsø Rederi AS

    The Wärtsilä 31 engine, which has been recognised by Guinness World Records as being the world’s most efficient 4-stroke diesel engine, has been chosen as the main engine for a new purse seiner/trawler.

    Read more
  • Fishing-Trawler-for-Strand-Senior-AS
    Strand Senior AS

    The best-in-class fuel efficiency of the Wärtsilä 31 engine means also that the exhaust emissions are correspondingly minimised.

    Read more
  • FSUE Atomflot
    FSUE Atomflot

    The new generation icebreaker Aker ARC 124 will feature three 8-cylinder Wärtsilä 31 engines.

    Read more

Insights on Wärtsilä 31

Modularisation hand in hand with manufacturability
29 May 2018 · Article
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Modularisation hand in hand with manufacturability
The development of the new Wärtsilä 31 engine provided the perfect opportunity to exploit the...
Wärtsilä 31
1 Jun 2015 · Article
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Wärtsilä 31 – the most efficient engine in the world
The Wärtsilä 31 marine engine sets the standard for energy efficiency. It has the lowest fuel...
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26 Apr 2017 · Article
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Common rail fuel injection rules the waves
Very few marine engines are awarded a Guinness World Record. Thanks to Wärtsilä’s common rail injection...

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