The Wärtsilä 31SG is available in 8 to 16 cylinder configurations and has a power output ranging from 4.2 to 8.8 MW, at 720 and 750 rpm. The launch of the Wärtsilä 31SG introduces a 4-stroke engine having the best fuel economy of any engine in its class. At the same time, it maintains outstanding performance across the complete operating range. Its modular design enables a significant reduction in maintenance time and costs, thereby improving power availability and reducing the need for spare parts.
The Wärtsilä 31SG retains its high efficiency and environmental values throughout the entire lifecycle of the vessel
The Wärtsilä 31 is designed to be suitable for a broad range of ship types and applications, in diesel electric configurations, or as an auxiliary engine. Wärtsilä 31 is a perfect solution for FSRU, LNG carrier´s, ferries and other vessel segments where operational flexibility, high power density, long intervals between overhauls, and high levels of safety are of paramount importance.
The SG engine ignites the gas fuel with the aid of a spark-plug instead of a liquid pilot fuel injection. The SG engine thus uses only gas as a fuel and does not need to be fitted with a separate back-up diesel fuel system.
The marine SG pure gas engine represents the lowest total cost of ownership with the lowest environmental footprint for operation in areas with a secured gas supply, for example on fixed short routes where gas bunkering infrastructure is available.
The Wärtsilä 31SG engine is well-suited for gases with a low methane number. The gas-only focus with spark-ignition and the absence of a back-up diesel mode allows for a wide range of optimization possibilities.
Marine classification society rules dictate that a gas-powered single-fuel vessel must typically have redundant back-up power available corresponding to min. 40% of MCR. This requirement can be fulfilled with SG machinery using a redundant gas supply system (2 x C-tanks for example) and selecting a multi-engine configuration.
The Wärtsilä 31SG in a hybrid engine-battery configuration enables a significant reduction in engine running hours which can save up to 5-20% in maintenance cost. The redundancy and peak shaving capabilities of a hybrid system also allows for a higher average engine load. Together these factors translate into a lower fuel bill and corresponding reduction in greenhouse gases. The savings in fuel and emissions are typically 2-6% on top of the savings achieved with the switch to SG technology.