Wärtsilä 31SG – best fuel economy

Wärtsilä 31SG sets a new benchmark in efficiency and overall emissions performance in connection with hybrid solutions. Its modular design makes it easier to maintain as well.

Get the facts: open the brochure

Wärtsilä 31SG

Designed to set a new benchmark in efficiency and overall emissions performance in connection with Hybrid solutions

The Wärtsilä 31SG is available in 8 to 16 cylinder configurations and has a power output ranging from 4.2 to 8.8 MW, at 720 and 750 rpm. The launch of the Wärtsilä 31SG introduces a 4-stroke engine having the best fuel economy of any engine in its class. At the same time, it maintains outstanding performance across the complete operating range. Its modular design enables a significant reduction in maintenance time and costs, thereby improving power availability and reducing the need for spare parts.

Key benefits of the Wärtsilä 31SG

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

  • Lowest fuel consumption over a wide operating range
  • Full output available for a broad range of gas qualities
  • Meets the IMO Tier 3 regulations 
  • Reliability is guaranteed through extensive validation and Wärtsilä’s vast manufacturing experience
  • Supported by Wärtsilä’s extensive global service network

Open the Wärtsilä 31 brochure


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. Wärtsilä 31 is a perfect solution for FSRU, LNG carrier´s, ferries and other vessel segments where operational flexibility, high power density, long intervals between overhauls, and high levels of safety are of paramount importance.

Wärtsilä Methane Number Calculator

Wärtsilä 31SG Product guide and 3D models and drawings

Get technical data and system proposals for designing W31SG marine engine installations.

Wärtsilä 31


FAQs Wartsila 31SG

How is the pure gas engine different from the dual fuel engine?
Is the pure gas engine replacing the dual fuel engine?
When should the pure gas (SG) engine be selected instead of the dual fuel (DF) engine?
Is the pure gas engine suitable for heavier gases with a lower methane number?
How does the single-fuel pure gas engine comply with the redundancy requirements of the marine sector?
What are the benefits of a pure gas-hybrid application?

Expand all

Collapse all


Orders stream in for Wärtsilä 31
28 Mar 2018 · Article
3 min read
Orders stream in for Wärtsilä 31
The demand for what the Guinness Book of World Records calls ‘the world’s most efficient 4-stroke engine’, the...
Modularisation hand in hand with manufacturability
29 May 2018 · Article
5 min read
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
7 min read
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...

Press releases

Wärtsilä Marine. Let's connect.