Piston-running behaviour and its effect on the wear of piston rings and cylinder liners are today largely the determining factors for the time between overhauls (TBO) achieved by low-speed twostroke marine diesel engines. They also have a major influence on ship operating costs through the time off-hire required for overhaul and the costs of spare parts and cylinder lubricating oil. The current targets are three years' TBO (about 20,000 hours' operation) as standard and low cylinder lubricating oil feed rates. This paper will report on the development work undertaken in recent years for piston-running tribology in W artsil large-bore low-speed two-stroke marine diesel engines to meet these targets. The main emphasis will focus on the development work which has been concentrating on the RTA96C and RT-flex96C engines. This recent development work began with a broadranging study of factors that influence piston running, and the response to these factors of the respective study was also performance results from recent modification measures that had been introduced to improve piston-running tribology. The result is a refinement of the specification of components involved with piston-running tribology. These have led to a moderate lowering of cylinder liner temperatures, while still keeping as far as possible above the dew point throughout the piston stroke. Cylinder liners are now plateau honed over their full length to improve further the surface for long-life performance. Chrome ceramic-coated piston rings are also applied in all ring grooves to meet the TBO target. The Anti-Polishing Ring fitted at the top of the liner has been adapted to be more effective in removing carbon deposits. The newly-introduced 'underslung' type of scavenge air receiver has already shown that it considerably improves water separation from the scavenge air - an important fact for good piston-running performance. Finally the latest adaptation of the well known multilevel CLU3 lubrication system is shown.
Progressive development of two-stroke engine tribology
2007
10 Seiten, 15 Bilder, 4 Quellen
Conference paper
Storage medium
English
Progressive development of 2-stroke engine tribology
British Library Conference Proceedings | 2007
|British Library Conference Proceedings | 2013
|TIBKAT | 1993
|TIBKAT | 1992
|The Tribology of Engine Design
SAGE Publications | 1992
|