Wärtsilä lifts output of 31DF engine

By applying new settings and tuning of the engine, the upgraded 31DF will increase its power output per cylinder to 600kW. This upgraded engine is claimed to offer a 9% increase in power per cylinder. The BMEP will increase from 27.1 bar to 29.6 bar.

The new settings are also expected to improve the combustion of methane, and reduce methane slip. This in turn results in lower levels of greenhouse gas emissions.

Wärtsilä estimates that the total reduction in GHG would be around 3% for a typical ferry operating profile, based on four Wärtsilä 31DF installed.

The increase in power, compared with the current 31DF-series engines, means the same power demand can be met with fewer cylinders. This will give significantly lower maintenance costs and will offer space advantages where engine room space is at a premium. Importantly, the increase in power output will not alter the 31DF engine platform’s dimensions, thereby delivering greater performance within the same physical footprint.

The Wärtsilä 31 engine was introduced in 2015 and recognised by Guinness World Records as being the world’s most efficient 4-stroke diesel engine.

The engine platform consists of 6, 8, 10, 12 and 16-cylinder main engine and genset variants. The power upgrade will result in the current output range of 4.2 to 11 MW, being increased to a range of 4.6 to 12 MW with 600 kW/cylinder at 750 rpm, and 580 kW/cylinder at 720 rpm.

The fuel-flexible engines are capable of burning natural gas, marine light fuel oil, as well as heavy fuel oil. They are said to have become increasingly popular for installation on a range of vessel types, including among others, cruise ships, ferries, tankers, and fishing vessels.

“This power upgrade to the Wärtsilä 31DF represents significant added value to our customers,” says Janne Klemola, General Manager, Product Management Small and Medium bore, Wärtsilä Marine. “Getting more power from an engine that already delivers exceptional efficiency, low emissions, and fuel flexibility is a real benefit. Regardless of whether the engine is installed on ships for propulsion or in land-based power plants for electricity generation, achieving this upgrade with fewer cylinders lowers the lifecycle costs, while at the same time reducing both the installation and maintenance costs.”

Wärtsilä 31DF specifications – main engine