Crankcase Venting System - BMW N62B44 Manual

Crankcase Venting System

The crankcase vapors (a result of combustion blow-by gasses) are led out of the crank-
case and back into the combustion chamber via the intake manifold. The blow-by gasses
contain droplets of oil which must be separated. The oil is returned to the sump while the
blow-by gasses are led into the intake pipe for combustion.
The engine performance is affected by the introduction of crankcase vapors into the com-
bustion process, particularly in idle speed ranges. This influence is monitored by lambda
regulation.
The crankcase vapors are carried from the crankcase and into the cylinder head covers
through labyrinth separators (one per cylinder head). The oil which accumulates on the
walls of the labyrinth separators flows into the cylinder head via a siphon and from there
back to the sump.
1-4. Opening for Spark Plugs
5. Pressure Control Valve
6. Opening Valvetronic Motor
7. Opening Valvetronic Sensor
Connector
8. Camshaft Sensor
The remaining vapors are passed to the engine for combustion via the pressure control
valve (5) in the intake manifold. One labyrinth separator with a pressure control valve is inte-
grated in each of the two cylinder head covers.
The throttle valve is controlled so that there is always a 50 mbar vacuum in the intake man-
ifold. The pressure control valve regulates the crankcase pressure to a low 0-30 mbar.
12
N62 Engine
Cylinder Head Cover
43-02-12