Most efficient 4-stroke diesel engine

According to Official Guinness Records,

The most fuel efficient 4-stroke diesel engine is the Wärtsilä 31, a marine engine manufactured by Wärtsilä (Finland). The engine has a fuel efficiency of 165 g/kWh, as verified on 26 May 2015. Efficient use of fuel helps to reduce emissions from shipping.

For a complete list of 2015 records, please visit 2015 Guinness Records in Finland.

Related Images

Other Finland records that might interest you:

• Largest number of amateur radio contacts in a year
• Longest open ocean journey by aquabike (jetski) - unsupported
• Largest gathering of people dressed as videogame characters
• Largest jackpot payout in a non-pooled online slot machine game
• Greatest distance in 24 hours of Nordic skiing (male)