In recent years, legislative changes and financial pressures have driven ship owners and operators to adopt new operational strategies; as a consequence, operational flexibility in terms of main engine loading and fuel choice has become not only a need, but a proven solution used to address environmental and economic performance needs of the marine transportation sector (particularly in the container vessel segment). In this context, a broader operational window for modern low speed 2-stroke marine diesel engines has introduced new challenges that need to be considered in cylinder lubrication and have highlighted new performance required of the cylinder lubricant in order for it to deal more effectively with these changes. The influence of a highly variable operational profile results in a cylinder lubricant being exposed to stress levels that until now, it has not been optimally designed for. This paper provides a summary of new investigations into low speed 2-stroke cylinder oil stress under a broad range of operational conditions and presents these findings as the basis for the design of a wide range cylinder lubricant that is able to outperform traditional 70 BN cylinder lubricants across a highly flexible operational profile in terms of fuel choice, ambient conditions and engine loading. As part of the development process of a wide - range cylinder lubricant, the paper will discuss some aspects of how a fundamental understanding of oil stress in the low speed 2- stroke diesel engine has significantly increased the importance and relevance of using a laboratory engine. Recent developments of new test protocols and engine control systems of the Bolnes 3(1) DNL 170/600 laboratory engine will be discussed and highlighted, to show how it can be used to generate reliable and repeatable test data for the process of discovering and benchmarking candidate formulations, thus proving their robustness and readiness for testing in the field in a full size engine that is capable of discriminating the performance of a lubricant. In particular this paper will discuss the increasing relevance of using such testing as a means of challenging traditional approaches to base number and performance relationships. Finally, the paper will show summarized results of more than 30,000 accumulated running hours with Alexia S4 on a number of engine types, sizes, ages and operational profiles, referenced against previous conventional 70 TBN cylinder lubricants.
Cylinder Lubrication - Utilising the latest findings on Low Speed 2-Stroke Diesel engine oil stress from field and laboratory engine testing in the development of a Wide Range Cylinder Lubricant - Shell Alexia S4
2013
16 Seiten, 28 Bilder, 4 Tabellen, 3 Quellen
Aufsatz (Konferenz)
Englisch
CYLINDER AND ENGINE LUBRICATION
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