Launched in July 2011, GulfSea Cylcare EHP 5055 is the latest step in Gulf Oil Marine’s cylinder oil development programme. With the majority of Gulf Oil Marine’s customers trading globally, Don Gregory, Director for Innovation and Technology, said “Cylinder oil availability, cost effectiveness and superior performance is critical for Gulf Oil Marine’s customers.” In the 70’s and 80’s, most ships traditionally used 70BN cylinder oil with a viscosity grade of SAE 50. In the late 80s and early 90s, new engine designs created lubrication challenges, principally due to overcooled liners, resulting in scuffing and catastrophic wear. The lubrication solution at the time was higher BN and an SAE 60 grade.
Today emission regulations enforce a 1.0% fuel Sulphur limit in ECAs and 0.1% limit when alongside in EU ports. From the 1st August 2012 in excess of 40M mt of fuel will be consumed in the three main ECAs representing around 20% of global fuel oil sales. Continued use of an unsuitable 70 BN cylinder oil for extended operation in ECA's may lead to excessive deposits of unused additive components causing liner polishing and sticking ring packs.
Although ship operators could bunker two grades of cylinder oil, drawbacks include the need for duplicate cylinder oil storage tanks, working capital tied up the stored cylinder oil and the risk of human error during changeover and inspections. Slow steaming and super slow steaming, the introduction of longer stroke to bore ratios and the modification of exhaust valve timing are all conspiring to lower cylinder liner temperatures and potential to retain the combustion gases from the previous engine stroke. These conditions promote acid deposition and corrosion of cylinder liner walls. If unchecked this may lead to catastrophic wear with piston ring blow-by, scuffing and consequent failure through a combination of micro-seizure and abrasive wear.
The development of Gulfsea Cylcare EHP 5055 has had to balance the risks of piston crown deposits with high BN oils, against the loss of detergency and dispersancy with lower BN cylinder oils. The overbased ‘soaps’ that provide the high BN are also key components in maintaining ring pack free of deposits and dispersing soot and solids to be subsequently scraped down into the under piston space. The new cylinder oil had to achieve similar feed rates to the conventional 70 BN product and associated engine builder feed rate recommendations.
2011-2013: key period for innovative marine lubricants
With the current range of fuel sulphur between 1.0% S and 3.5% S this development work is the first step in meeting the longer term challenges of 0.1% Sulphur (2015 ECA sulphur limit) and the global 0.5% Sulphur limit (2020). Sea trials have proven the success of the 5055 product; as have over 12 months of commercial operating experience.
Gulfsea Cylcare EHP 5055 is a conservative approach, addressing the fundamental challenges of reliability, cost effectiveness and flexibility to meet the many changes that are happening. There are no rash claims, of unquantified performance features. With OEMs facing the consequences of both operating changes and novel cylinder all claims, the Gulf Oil Marine approach continues to support the key essentials of reliability and economic benefits of two-stroke engines.
Evaluation of low viscosity grades is on-going. “Have we really utilised the benefits of the modern lubricator systems by sticking to SAE 50,” questions Gregory, adding that reliability and cylinder liner conditions are absolutely paramount.
Lubricant suppliers can participate in the challenges the industry faces and Gulfsea Cylcare EHP 5055 is one such contribution. But good seamanship and engineering diligence is an essential requisite of economic and reliable performance. Frequent cylinder and piston condition inspections, photographic records and written notes will always help identify deteriorating conditions, before they cascade into a costly and risky failure.
Gulf Oil Marine’s strategy for satisfying the cylinder all lubrication needs of our customers is to continue to supply Gulfsea Cylcare DCA 5070H, a 70 BN cylinder oil for vessels operating globally with only occasional or short periods in the ECAs. For a more flexible approach, avoiding the need for multiple grades of cylinder oil, vessels on global and ECA trading patterns customers have the opportunity to choose Gulfsea Cylcare EHP 5055. Gulf Oil Marine also continues to supply Gulfsea Cylcare DCA 5040H, a 40 BN cylinder oil for continuous operation on low-sulphur fuels such as those bunkered in some parts of South America.