Wärtsilä Introduces Gas-Fueled Version of ‘World’s Most Efficient 4-Stroke Diesel Engine’

Wärtsilä 31SG
Wärtsilä 31SG coming off the factory line in Vaasa, Finland. Photo credit: Wärtsilä

Finnish technology group Wärtsilä has introduced a gas-fueled version of its Wärtsilä 31 marine engine, which is recognized by Guinness World Records as the world’s most efficient 4-stroke diesel engine.

The engine, dubbed the Wärtsilä 31SG, builds on the efficiency of the successful Wärtsilä 31 engine, but with added flexibility and efficiency compared to its conventionally-fueled and dual-fuel predecessor.

“The defining feature of the Wärtsilä 31SG is its ability to achieve simple-cycle efficiency levels in excess of 50 % (compared to around 40 % with modern gas turbines), which represents a milestone achievement in the energy sector,” according to Wärtsilä. “In addition to reducing emissions, this higher efficiency offers the potential for considerable cost savings to power producers.”

The 20-cylinder, spark-ignited Wärtsilä 31SG produces 12 MW of power. The specially designed robust engine structure has an unprecedented brake mean effective pressure (BMEP) of 30 bar, allowing it to fully accommodate all the benefits of two-stage turbocharging, explains Wärtsilä.

“Another huge benefit made possible by the Wärtsilä 31SG is the increased flexibility which enables rapid response to continuously changing load patterns, especially within systems having a notable share of solar and wind energy. The engine can be continuously operated at 10 percent load, and can reach full load in two minutes from the start command. This flexibility overcomes the challenge created by the daily stops and starts that are inevitable with output from renewable sources,” the company says.