Santa Claus, saunas and now the most efficient bit of heavy metal in the world
Not satisfied with being the home of the sauna and Santa Claus and having the most heavy metal bands per capita in world, those devious Finns have used a heap of other heavy metal to build an enormous engine that’s just taken its place in the Guinness Book of Records. This mind-boggling structure in the form of an 89-foot high, 44-foot long, 110,000 horsepower from the engineering company Wärtsilä is now the world’s most efficient four-stroke diesel engine.
Designed for medium-sized ferries and cruise ships, or small to medium tankers and container ships, the new Wärtsilä 31 engine isn’t nearly as huge as the mammoth RTA96-C. It stands a more modest 15.4 feet (4.7m) tall in its highest configurations and 28.8 feet (8.7m) long in its longest with a cylinder bore of 12.2 inches (31cm) and a 16.9 inch (43cm) stroke. In its largest V16 format it can churn out 13,142 horsepower.
There are three versions: diesel, spark-ignited gas and dual fuel with the diesel taking advantage of advanced fuel and air injection systems and variable valve timing to deliver a world record efficiency of just 0.271 pounds per horsepower hour. To put that in context, the gigantic RTA96-C was the most efficient engine in the world upon its debut and it uses 0.278 lb/horsepower hour.
That’s a saving of about 2.6% that might not sound like a lot, but these things can burn an enormous amount of fuel in a day. If, for example, the most powerful version of the 31 was run flat out at maximum power for a whole day and assume it made the same efficiency figure (it wouldn’t, of course, but stay with us) the engine would burn nearly 40 tons of diesel. So a 2.6% saving is going to add up to a heck of a lot of diesel over the service life of the engine.
It’s also worth noting that there’s no efficiency penalty a Wärtsilä’s nitrous oxide reduction system is fitted to the engine to keep emissions down, which is a requirement for operating in certain areas. The 31 also saves operators money in maintenance, running some 8000 hours before it needs its first service. The team at Wärtsilä must deal with some incredible engineering challenges to build these impressive machines not wonder Santa Claus can get all around the world in 24-hours.