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