Meet Wärtsilä 31 – The World’s Most Efficient Engine

A lot has changed since the invention of the internal combustion engine some 200 years ago. When you think about it, this 18th-century principle still drives so much of today’s power generation after decades of tweaking and refining. So what’s the agreement? There’s still a lot of room for design enhancement.

And that is what Wärtsilä engineers have done exactly. Wärtsilä’s newest engine has a 50 percent higher efficiency than any other in the industry. The key to its success is a revolutionary new design that was created from the ground up and is strong enough to endure the tremendous mechanical stress associated with two-stage turbocharging.

Revolutionary Design

Wärtsilä’s engineers had the unique chance to evaluate all of the numerous elements that contribute to engine efficiency and make adjustments to each to get the greatest benefit available when designing a new engine from the ground up. It was necessary to investigate and handle a wide range of difficulties, including internal friction, engine specifications, and heat and flow loss prevention.

An engine construction specifically built to allow two-stage turbocharging is the most significant advancement in the Wärtsilä 31. Because no current engines could take full advantage of the substantial increase in efficiency associated with two-stage turbocharging, even though the industry had previously been experimenting with it for quite some time.

A sudden increase in firing pressure caused them to break down under the weight and pressure. That is why Wärtsilä 31’s engine construction has an exceptional break mean effective pressure of 30 bars.

The Result

Wärtsilä’s new 31 four-stroke engine is the most fuel-efficient engine currently on the market. The diesel variant of the engine uses 8–10 g/kWh less fuel on average than the nearest rival over the whole load range. This value may be as low as 165g/kWh when operating at peak efficiency.

The massive Wärtsilä 31 engine was just awarded the “Most Efficient 4-Stroke Diesel Engine” by Guinness World Records, and Roger Holm, Senior Vice President, Engines, Wärtsilä Ship Power, said that “it certainly redefines efficiency.” At more than 13 feet tall and with a variety of engine combinations, the huge diesel is one of the most fuel-efficient vehicles on the road today.

It consumes just 165 grams of diesel per kilogram of power while satisfying today’s environmental standards.

Wärtsilä 31 Market

The Wärtsilä 31 engine is intended for use in a variety of vessels in the Offshore, Cruise & Ferry, and other marine segments with power requirements ranging from 4.2 to 9.8 MW. To accommodate various types of fuel, three distinct engine variants are available: diesel, dual fuel (DF), and spark-ignited gas (SG).

The Wärtsilä 31’s ability to run on a variety of fuels, from ultra-light diesel to extremely heavy diesel, as well as various grades of gas, expands the options available to operators.

Less Maintenance

Since it has a wide bore and long stroke of 16.9 inches, the V-16 has a massive 519.3L displacement, making it the most powerful of the trio. At 750 revolutions per minute, it generates 13,088 horsepower (818 horsepower per cylinder), or 9.8 megawatts of power generation enough to power the typical American house for a full year!

In addition to saving money, the engine’s modular design allows individual cylinder components to be replaced out, saving time and money for owners. 5 years or 32,000 hours of operation are necessary before the first overhaul is scheduled, and an 8,000-hour maintenance interval is required before the first maintenance interval (2,000 hours for engines with similar power output).


  • Layout: V-16
  • Displacement: 519.3L (31,688ci)
  • Bore x stroke: 12.2 x 16.9 inches (310 x 430mm)
  • Power: 13,088 hp at 750 rpm
  • Piston speed: 24.04 mph (10.75 m/s)
  • Fuel consumption: 165 g/kWh
  • Length: 28.8 feet (8,780 mm)
  • Width: 11.2 feet (3,400 mm)
  • Height: 13.3 feet (4,050 mm)
  • Weight: 85 tons (170,000 pounds)

Here are some interesting videos about the engine for more information:

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