Freudenberg-NOK wins first automotive seal order

Freudenberg-NOK wins first automotive seal order

Levitex seals use air-cushion system to lower friction in engines, transmissions.

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October 10, 2015

Plymouth, Michigan – Freudenberg-NOK Sealing Technologies (Freudenberg-NOK) has won its first major order for its new generation of automotive seals. The frictionless Levitex seals, a subject of the company's research for years, 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.

Levitex seals initially will be produced in Europe although the company plans to expand product into North America in the future as customer demand grows.

In any internal combustion engine, seals make sure that oil stays where it belongs: in the engine. As a result, the intersection between the engine and transmission is an important sealing point. There the crankshaft ends with a shaft seal at the crankcase. As essential as the seal is, it produces a substantial amount of friction with every engine rotation, converting valuable torque into heat energy losses.

With Levitex, Freudenberg-NOK has developed a new generation of mechanical seal that produces almost no friction at all. The resulting CO2 reductions – as high as 1 gram per kilometer driven – are significant.

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. It is only the new design, patented by Freudenberg-NOK, and its associated production process that allow the idea to be carried over to the internal combustion engine, where there is little space available for its installation.

Engineers at Freudenberg-NOK prepared for the launch of the Levitex technology into series production with exhaustive testing, where the sealing rings had to demonstrate their flawless functioning in extreme temperatures, ranging between -40°C and 150°C. Neither extremely fine dust – like the "Arizona dust" that automakers use for their functional tests – nor the penetration of water were able to negatively affect the performances of the seals.

"At present, no other technology is known that allows the frictionless and secure sealing of the crankshaft," says Dr. Eberhard Bock, the head of strategic product development at Freudenberg Sealing Technologies. "In view of the ambitious CO2 goals that become effective in 2020, the focus will be on saving every gram. As a result, we are confident that we will succeed in finding other customers for this innovative technology."

Source: Freudenberg-NOK Sealing Technologies