Two-stroke developments for fuel saving

摘要

2018 is an interesting year for the two-stroke marine engine. For the first time, a two-strokemarine engine has reached 200 bar in maximum cylinder pressure. Despite the largedimensions of the new G95ME-C10.5 containership engine, it runs with a maximum pressureof 200 bar. To move us even closer to the Carnot limit of efficiency, a similarly interesting stepis the utilisation of Tier III technology to increase engine efficiency in Tier II mode. We call itEcoEGR. Using EcoEGR significantly reduces the fuel consumption during the long hauls onthe open ocean outside Tier III areas. Such reductions in fuel consumption and, thereby, alsoCO2 emissions are much welcomed by the industry, and further emission reductions can beachieved by using new fuels. LNG in particular represents a strong reduction in CO2 emissionsand has no significant emission of Sox. But also fuels such as LPG, methanol and ethanereduce the emission of CO2 and Sox from the ship. Dual fual engines for these fuels are nowavailable. An additional method to reduce the fuel consumption is to move the electricalpower production for the vessel to the two-stroke engine by applying power take-out (PTO).In this way, the high efficiency of the two-stroke engine is also utilised also for production ofelectricity. In 2018, MAN has launched a new and simpler method for PTO called multi-hybrid.The aim is to simplify installation and reduce the dimensions of the PTO system.Encompassing it all is the vessel design spiral. Good hull and propeller designs provide thebasis from which the engine can improve the fuel consumption by the above-mentionedmethods, so the basis needs to be good and include the optimal propeller diameter for thevessel. The technological achievements outlined above and the engine selection process forlowest fuel consumption will be explained in the presentation.