Positive Crankcase Ventilation: Description and Operation

Crankcase Ventilation







1. Intake manifold connection
2. Turbocharger (TC) intake, connection
3. Connection, coolant pump intake pipe
4. Coolant outlet from the cylinder head
5. Coolant return
6. Crankcase gases to the intake for the turbocharger (TC)
7. Coolant from the cylinder head.

Evacuation
The evacuation system for the crankcase ventilation has been modified to ensure stable pressure in the crankcase. The crankcase gases are routed from the flame trap to, depending on the pressure conditions, the intake manifold (1) or the intake for the turbocharger (TC) (2).

When the pressure at the intake manifold is lower than at the intake for the turbocharger (TC), the gases flow to the intake manifold. When the pressure at the intake for the turbocharger (TC) is lower than in the intake manifold, the gases flow to the intake for the turbocharger (TC).

A non-return valve in the banjo screw for the crankcase ventilation connection (1) prevents the crankcase gases from returning to the intake for the turbocharger (TC) when the pressure is high. This ensures that the gases are correctly evacuated and that the pressure in the crankcase is stable.

Heating
Coolant is used to heat the crankcase gases to prevent freezing.

The coolant flows from a duct in the cylinder head (4) to a common pipe which fills with coolant (7). The coolant then flows to the crankcase ventilation connection to the intake manifold (1). The coolant returns through a separate pipe (5) to the inlet (3) for the coolant pump.

The crankcase gases which flow to the turbocharger (TC), are warmed in a separate pipe (6) in the common pipe (7).

The location of the components and connections corresponds to the system required for diagnostics and service by authorities such as CARB (California Air Resources Board).

The flame trap is insulated using PUR foam. The flame trap has a labyrinth which efficiently separates oil from the crankcase vapors.