【作者】

Dorthe M.S. Jacobsen

【摘要】

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。New types of fuels enter the marine market and novel combustion principles are introduced in MAN B&W engines. This imposes challenges to the traditional cylinder lube oils, cylinder lube oil supply systems and engine components. Here, MAN Diesel & Turbo Two-Stroke presents the lubrication challenges and latest experiences for operation on fuels with less than 0.1% sulphur (S). Our future cylinder lube oil supply systems, which cover the entire fuel S range from 0-3.5%, and new components, to overcome the risk of obstructions in oil-film formation, are also discussed. Until recently, marine low speed engines and cylinder lube oils have been optimised for operation on heavy fuel oil (HFO) with a high S content. The purpose of the alkaline additives in the lube oil is to neutralise the sulphuric acid condensed on the liner wall and thereby protect the components against corrosion. When operating on fuels with less than 0.1 %S, i.e. distillates, ultra-low sulphur fuel oil (ULSFO), liquefied natural gas (LNG), methanol, ethane and LPG, only small amounts of sulphuric acid is formed and the alkaline additives in the lube oil are not needed. The unused alkaline additives tend to form deposits in the combustion chamber and these can disturb the lube oil film, obstruct the piston ring movement, polish the liner surface and thereby increase the risk of scuffing. Newly developed cylinder lube oils are available to decrease these risks. For engines operating continuously on fuels with less than 0.1%S, two components which aim to reduce the risk of seizures, polished liner surfaces and scuffing are presented. Cermet coated rings show successful results and installing a full set of piston rings with cermet coating is recommended. Cylinder oils are usually optimized for a specific S range. Ships operating in the full S range from 0 to 1.0 to 2.0 to 3.5% require several lube oil types in order to have an efficient lubrication. The Automated Cylinder Oil Mixing (ACOM) system is the solution and requires only two oils and will be available for all engines types. The ACOM mixes low-BN oil and high-BN oil to the required BN to match the fuel S content. It mixes and delivers the lube oil mixture just-in-time which facilitates the process of optimizing the lubrication and cylinder condition. Using suitable lubricants, ACOM operation can cover the complete S range from 0-3.5% and facilitate optimised lubrication. The ACOM is presently out for service testing. The Automated Cylinder Oil Switching (ACOS) system is specially developed for ME-GI engines, and facilitates the lubrication during operation on LNG and high S HFO. It is controlled by the engine operating system and switches automatically between low-BN and high-BN cylinder lube oil based on S content in the actual fuel and load applied. The ACOS system is now standard for the ME-GI engines. Successful optimization of the lubrication and improvement of the cylinder condition are dependent on that the condition is followed closely and the operators act on the information obtained. The importance of on board analysis tools, i.e. drain oil analysis, port inspections and liner surface examinations, are described and discussed.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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