Worlds most efficient 4-stroke gas engine

Based on the Wärtsilä 31 product platform, the diesel version of the engine has been recognised by Guinness World Records as being the world’s most efficient 4-stroke diesel engine and will possibly pave the way for using alternative fuels such as LPG.

“The highly efficient Wärtsilä 31SG moves the industry forward by providing owners and operators with a practical means for lowering costs and enhancing environmental sustainability,” said Rasmus Teir, product manager, Wärtsilä Marine.

“The gas-only focus and lean-burn spark ignition technology allows for further optimisation of thermal efficiency, while lowering greenhouse gas emissions and facilitating adaptations for alternative heavier gas fuels, such as LPG,” he added.

Wartsila intends to initially bring out pure gas gensets by late 2021, and subsequently as main propulsion engines in 2022. The engines are intended to find a market in cruise and ferry segments, as well as in the FRSU segment. With five cylinder configurations – 8V, 10V, 12V, 14V and 16V – the engines have a mechanical output of 4240 – 8800kW and a cylinder output of 530/550kW.

Speaking at Gastech in Houston, Mr Teir noted that a comparison of three W12V31DF engines with three W12V31SG engines produced greenhouse gas savings of 18% for an FRSU, and that similar savings were seen for a RoPax. Combining the three pure gas engines with a battery hybrid configuration produced 22% savings and Opex savings of 4% and 8.9% have been seen, reflecting both fuel efficiencies and lower maintenance costs.