Function, high engine load

At high engine load, the pressure in the engine intake manifold is relatively high. There is therefore no reduced pressure which can draw the crankcase gases into the intake manifold. The check valve in this case is closed. The crankcase gases are passed from the oil trap via a hose to the turbo inlet, where reduced pressure predominates. Here the crankcase gases are mixed with the turbo intake air and passed to the engine cylinders via the engine intake manifold.

Fig 1: Pressure Flow Diagram (High Engine Load)

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