Friction Reduction, piston ring coating

New piston ring coating reduces ring friction up to 20%

Federal-Mogul has developed a new piston ring coating that supports vehicle manufacturers' efforts to make gasoline engines more fuel efficient.

The company says that its patented CarboGlide coating delivers a direct improvement in fuel economy and CO2 emissions by reducing ring friction by up to 20% as compared to nitride or other commonly used coatings. CarboGlide's high wear resistance will withstand an engine's full operational life – even in the latest generation of high-output gasoline engines with turbocharging or direct injection. CarboGlide also reportedly protects the cylinder surface from scuffing and scoring, especially under the most critical lubrication conditions, because of its high chemical and physical stability.

The product is Federal-Mogul's third and most advanced generation of its DLC coated-ring technology. The coating was developed in Burscheid, Germany, at one of the company's 18 globally networked technical centers. Several leading vehicle manufacturers will launch engines using Federal-Mogul's CarboGlide-coated piston rings beginning this year.

CarboGlide's impressive coating properties are achieved due to a multi-layer microstructure and a special coating composition that contains carbon, deposited in diamond-like form, as well as hydrogen and tungsten. The unique structure can be produced for a coating thickness of 10 microns, more than three times that of the industry's latest state-of-the-art DLC coating. A specialized advanced process based on the combination of physical vapor deposition and plasma-assisted chemical vapor deposition, specifically developed for piston ring applications, is used in applying CarboGlide. The coating's multi-layer architecture, together with the company's surface machining and finishing expertise, ensure the integrity of the coating structure, optimal adhesion of the coating, and high coating stability on both steel and cast iron rings.

"Federal-Mogul tests on engines, using both cast iron and high-silicon aluminum cylinder surfaces, have shown that CarboGlide-coated rings minimize friction and scuffing for the full expected life of the engine, even in the challenging environment typical of GDI turbo engines," says Dr. Marcus Kennedy, Federal-Mogul's manager, Physical Coatings. "It is highly stable due to its non-metallic nature. The unique combination of low friction, low wear, and scuffing resistance also makes the technology attractive for application to other Federal-Mogul products developed for extreme conditions like face seals on construction machinery."

...might find application in other parts of our boats...