Oil vapour recirculation system (blow-by)

OIL VAPOUR RECIRCULATION SYSTEM (BLOW-BY)

Oil vapour emissions are controlled by separator (1) which receives oil vapours from the cylinder head and engine block.

As they flow through the separator, the vapours lose part of their oil content, which condenses and returns to the sump through pipe (2). The remainder is taken up by the engine through pipe (3). Vapour intake is controlled by flow limiting valve (4). This valve is fitted close to the insertion point of pipe (3) on intake sleeve and gradually reduces its cross section as engine intake vacuum rises in order to reduce the flow of incoming vapours.

1. Vapour separator
2. Oil return line to sump
3. Vapour delivery line to intake
4. Flow limiting valve
5. Oil filler fitting
6. Vapour uptake from engine block
7. Vapour uptake from cylinder head