Tribologie N

Naphtene
Outdated term for saturated cyclic hydrocarbons, also called cycloparaffin or cycloalkane, generally 5 or 6 hydrocarbon atoms in the ring (more rarely 7 and 8).
 

Naphtha
This is the designation for a raw gasoline with a boiling range from 30°C to 150°C. The quality of the petroleum varies greatly depending on where it comes from.
 

Natural gas
Is present in petroleum and in separate reservoirs below the surface of the earth; it is mostly methane.
 

Neutral oils
International designation for high-grade refined products, e.g. solvent refined products.
 

NLGI
National Lubricating Grease Institute.
 

NLGI classes
Classification of consistency (penetration classes) for lubricating greases: DIN 51 818.
 

Noack-Test
It determines the volatility losses of a lubricating oil at high temperatures; evaporating loss of a lubricating oil is equivalent to oil consumption in the engine; this causes the properties of the remaining lubricating oil to change: DIN 51 581, CEC L-40-T-87 – see volatility loss.
 

Normal lubricating oil AN
These are pure mineral oils that are to be used for lubricating purposes but which do not place any special requirements on the lubricants. DIN 51 501.