Frictionless engine seals

Freudenberg-NOK Sealing Technologies has announced its first major order for its new generation of automotive seals. The frictionless Levitex seals, a subject of a long research and development process, will go into an engine for a global platform in 2017. The new seals function with a cushion of air, reducing both fuel consumption and CO2 emissions—by as much as 1 g/km driven, the company claims. Levitex seals initially will be produced in Europe although the company plans to expand product into North America in the future. A Levitex seal consists of two rings, one of which is firmly attached to the crankshaft and the other to the crankcase. One of the rings has grooves that are just a few micrometers deep. When the crankshaft rotates, the air is dragged against the sealing dam that encloses the grooves. The grooves taper to a closed tip and thus represent a cul-de-sac for the enclosed air. This produces a cushion of air that separates one sealing surface from the other, making possible a nearly frictionless seal for the shaft. Until now, gas-lubricated mechanical face seals were exclusively used in major industrial facilities, according to Freudenberg-NOK. The supplier’s new patented design and its associated production process allow the idea to be carried over to combustion engines, where space is limited. During testing prior to series production, the sealing rings demonstrated “flawless functioning” in temperatures ranging between -40 and +150°C (-40 to +302°F), claims the company.

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