30
SSP 198/07
Engine
The crankcase breather ...
...comprises a distributor piece, a pressure
limiting valve, a non-return valve and the
associated hoses.
The oil vapours and “blow-by“ gases from the
cylinder heads and the crankcase converge in
the distributor piece.
The pressure limiting valve and the non-return
valve control the return of these vapours and
gases to the engine, depending on the intake
manifold pressure.
Vacuum in intake manifold:
The oil vapours and “blow-by“ gases return
via the non-return valve in the intake manifold.
charge pressure in intake manifold:
The oil vapours and “blow-by“ gases return
via the pressure limiting valve in the air
distributor.
The
pressure limiting valve
limits the vacuum
in the crankcase. If the vacuum in the
crankcase exceeds a defined value, the
diaphragm is drawn over the connection
against the force of the spring and closes the
connection. The valve is designed in such a
way that it allows a small quantity to pass
through when closed. This prevents the engine
oil being drawn into the intake tract and has no
adverse effects on engine breathing.
Distributor piece
Pressure limiting valve
Non-return valve
The term “blow-by“ gases refers to
the gases which escape from the
combustion chamber past the piston
rings.
Connection
Diaphragm
Air distributor
to air
distributor
from
distributor
piece
Summary of Contents for 2.7-litre V6 Biturbo
Page 47: ...48 Notes ...
Page 71: ...72 Notes ...
