Positive Crankcase Ventilation: Description and Operation

Breather & Adaptor:

Intake Manifold:

A breather adapter assembly is introduced to the part-load breather, replacing the stub pipe, restrictor and engine coolant passages previously integrated into the intake manifold.

The adapter assembly, attached to the intake manifold with a dowel and bolt, consists of a casting with four stub pipes. Pairs of the stub pipes, for the part-load breather and for the engine coolant, are connected by separate passages in the casting. The part-load breather passage contains a 2.5 mm nominal diameter restrictor, to prevent reverse flow. The flow of engine coolant through the adapter assembly prevents the formation of ice in the restrictor at low ambient temperatures.

The outlet stub pipe for the part-load breather directs breather gases to the lower part of the intake manifold interior, away from the exhaust gas recirculation valve. A press fit, rubber lined cartridge assembly provides the seal between the outlet stub pipe and the manifold.