Freudenberg-NOK Sealing Technologies is presenting its revolutionary Levitex® crankshaft seal – capable of reducing crankshaft friction up to 90 percent – at the 35th International Vienna Motor Symposium today.
Freudenberg-NOK will present the innovation in response to the European Union’s goals of reducing total carbon dioxide (CO2) emissions to 95 grams of CO2 per kilometer by 2021.
The gas-lubricated Levitex mechanical face seal comes very close to the vision of a frictionless seal. The seal consists of a stationary primary ring and – on the oil side – a rotating mating ring. During operation, grooves creating an aerodynamic effect form an air cushion that separates the two rings. The primary and mating rings also have a special coating to reduce wear and friction when the crankshaft is at rest.
Independent measurements of the Levitex seal on a seal test stand are already showing greatly reduced friction even at low rotational speeds. The measured frictional torque is 0.2 to 0.3 Newton meters lower than the values for a friction-optimized polytetrafluoroethylene (PTFE) seal and a standard PTFE seal. The remaining friction is due to air shear.
The Levitex crankshaft seal will help auto manufacturers address friction reductions in the engine and drivetrain, a key to reducing vehicle CO2 emissions. A radial shaft seal typically seals a rotating crankshaft at its housing. An oil film minimizes its contact with the shaft. Still, the remaining loss of performance can be as high as 1 gram of CO2 per kilometer.
With the new Levitex seal, the frictional losses from a crankshaft seal are reduced by up to 90 percent compared to a standard PTFE seal. This leads to less fuel consumption and wear, as well as a longer service life. Further, CO2 emissions at the sealing point fall from the 0.5- to 1-gram range to less than 0.1 grams under the New European Driving Cycle.