Federal-Mogul debuts eWave piston ring

The piston rings’ topography has been designed to distribute oil more evenly around the cylinder bores. The company cited long-term trials – clocking up 8,000 hours of testing across several vessels since 2013 – showing improved wear resistance, with chief engineers able to reduce lube oil consumption by up to 20%.

Richard Mittler, senior expert manager, analysis and product development, technology, rings & liners said: “eWave is the first ring that disperses oil around the bore in a homogeneous layer, protecting against local oil film breakdown, improving the sealing of combustion gases, reducing wear and ensuring more uniform liner temperatures.

“This means the amount of oil injected into the cylinder can be greatly reduced and, because two-stroke engines expel their lubricant in the exhaust, less oil means lower carbon emissions as well as reduced operating costs.”

Lube oil is fed differently into two-stroke engines as opposed to four-strokes, yet conventional piston rings are designed in a similar way for both types of machine, the company noted. As two-stroke lube injection does not always ensure a uniform film, surplus oil is used to ensure protection – much of it going straight out as exhaust gas. The eWave’s shape creates a pressure difference that controls the oil flow around the bore and improves film uniformity.

The company added that the design can be optimised to suit individual types and arrangements of feed nozzle and different engine strokes and operating speeds.

The Motorship understands that Winterthur Gas & Diesel worked closely with Federal-Mogul on the development of the piston ring design.