Crankcase Venting System - BMW N62 Series Service Training

New Generation N62 Engine

- Crankcase venting system

General information
The gases which penetrate the crankcase as a result of combu-
stion (blow-by gases) must not escape outside into the
atmosphere. This is why they are led out of the crankcase and
back into the combustion chamber via the intake manifold.
The blow-by gases contain droplets of oil. If these blow-by
gases carrying droplets of oil were to be fed into the engine
combustion zone, there would be the following consequences:
- Higher oil consumption
- An effect on pollutant emissions
- Blue smoke
In order to avoid this, the blow-by gases must be separated from
the engine oil. The oil is returned to the sump once separated.
The blow-by gases are led into the intake pipe for combustion.
Engine running is affected if the blow-by gases are returned to
the combustion process, particularly in near-idling speed
ranges.
This influence is taken into account by lambda regulation.
The blow-by gases must be intentionally passed into the intake
tract to avoid negative side-effects
© BMW AG, Service Training
Course Contents/Background Material
Chapter 3 P.13