|The LKZ oil control ring, unlike conventional or standard oil rings, combines a stepped surface and taper on its contacting edge, or “land,” and reduces oil consumption by up to 50% and friction by up to 15%. Click to enlarge.|
Federal-Mogul Corporation has introduced a two-piece oil ring design for gasoline direct-injection engines, previously developed for diesel applications. The patented LKZ oil control ring reduces oil consumption by up to 50% and friction by up to 15%, compared to the best conventional two-piece oil rings, according to the company. The additional benefits of this improved engine performance are fuel economy, CO2 reduction and longer oil life.
Typical piston rings apply equal pressure to the cylinder bore on the downstroke, toward the crankcase, and on the upstroke, toward the combustion chamber. Federal-Mogul’s LKZ ring combines a stepped surface and taper on its contacting edge, which provides a well-defined pressure to the cylinder wall on the downstroke and a significantly lesser effect on the upstroke.
The downstroke pressure more effectively returns the oil that lubricates the cylinder to the oil pan, as opposed to allowing oil to enter the combustion chamber where it may create carbon on the spark plug or on the cylinder head and increase oil consumption.
The LKZ ring is so effective in pulling oil away from the combustion chamber and in reducing oil consumption that we are able to improve ring tension and reduce friction. Reduced ring friction requires less energy, which means better fuel economy and less CO2 emissions.
The LKZ ring, unlike conventional oil rings, also provides consistent low oil consumption over the life of the engine by reducing carbon build-up on critical parts of the piston, such as just above the compression ring. Carbon build-up on the piston can lead to cylinder liner damage and increased oil consumption. The LKZ ring helps to mitigate that concern for vehicle manufacturers and consumers.
—Johannes Esser, Federal-Mogul’s director of engineering, Rings and Liners
LKZ rings are one of several rings offered by Federal-Mogul. Depending upon the level of wear resistance required by engine manufacturers, Federal-Mogul can apply a variety of surface treatments to piston rings, such as chrome, CKS (chrome ceramic coating) and GDC (Goetze diamond coating), which protect the ring periphery from scuffing, thus minimizing wear and enabling the oil ring to function properly over the life of the engine. The LKZ ring also can be coated with Federal-Mogul’s DLC (diamond-like carbon) coating to even further reduce engine friction.