System oil for 2-stroke marine engines - current and future performance requirements and challenges
(0) System oil has had a slow evolution of performance improvement during the past decades. Rapidly increasing fuel injection pressure to reduce fuel consumption and to meet exhaust emission requirements requires increased anti-wear performance to protect gears, camshafts and followers. The introduction of engines with complex hydraulic systems operated by the system oil necessitates a review of the current situation. The oil needs to be very clean to operate effectively in these functions as there are many delicate high precision control components in the hydraulic oil control circuit. The system oil also operates in an increasingly hot piston cooling and exhaust turbocharger bearing environment necessitating improved thermal stability and anti-oxidation properties. Some new bearing materials require low system oil water content and improved anti-corrosion properties. The quantity of system oil per engine output is also being reduced to save cost and space, thus the oil circulation rate is increasing. This requires that the air release and foam collapse time properties of the oil need to be improved. Not only the new oil performance for all these parameters is important, but the retention of these desirable properties for the life of the oil is essential to ensure good operation. System oils are typically ’fill for life’, thus these properties need to be maintained for the life of the engine , i.e. 25 to 30 years with only small amounts of top up. One final challenge would be to meet all these requirements as well as allowing the use of the system oil as a cylinder oil for use with low sulphur distillate fuel. These new performance requirements need to be addressed to ensure reliable engine operation now and in the future. To deliver the required performance, the choice of additive chemistries becomes critical. While the range of additive chemistries is extensive, the impact of new system oil requirements makes selecting the right molecules a key step in delivering performance to match engine needs. This is made even more so by the need to consider the impact on the environment and potential future legislation. In addition, as the automotive industry drives basestock manufacture to increased use of Group II, III, and IV product, the impact of these if used to produce system oils, must be taken into account. This paper aims to identify the performance requirements for system oils and show how with careful formulating, these can be achieved.
John Smythe Georg Bleimschein
Infineum UK Ltd,UK W(a)rtsil(a) Switzerland Ltd,Switzerland
国际会议
上海
英文
1-9
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）