Positive Crankcase Ventilation (PCV) System

The PCV-architecture of the turbo charged new 6-cylinder engine N54 is designed as a two way ventilation system. This two way ventilation system is designed in two separate connections between crankcase and intake manifold (please see figure).

Connection (1) is used at part load and ends after the turbo charger in the intake manifold. The PCV-valve used in this path is fastened directly to the crankcase. The line between the PCV-valve and the intake manifold is designed as an integrated system combined with valve hub.

Part load: 

Fig 1: Positive Crankcase Ventilation System Diagram - Part Load

Courtesy of BMW OF NORTH AMERICA, INC.

Connection (2) is used at high load and ends before the turbo charger in the intake manifold. In this line, including a separate check valve, a disconnection isn't possible without demolition of the concerned parts.

Full load: 

Fig 2: Positive Crankcase Ventilation System Diagram - Full Load

Courtesy of BMW OF NORTH AMERICA, INC.