Mitsubishi Evolution X. Manual - part 50
EMISSION CONTROL
TSB Revision
ENGINE AND EMISSION CONTROL
17-10
CRANKCASE VENTILATION SYSTEM
M2171000400260
A blow-by gas reduction device prevents blow-by
gas from being expelled into the atmosphere and is
of closed type. A positive crankcase ventilation
(PCV) valve is provided in the ventilation hose from
the rocker cover to the intake manifold. During low
load driving, clean air is supplied to the crankcase by
the air intake hose via the breather hose and rocker
cover, and it mixes with the blow-by gas in the crank-
case. The blow-by gas in the crankcase is induced to
the intake manifold through the rocker cover and
PCV valve. During high load driving, blow-by gas in
the crankcase is induced to the intake manifold
through the rocker cover and PCV valve and at the
same time also via the air intake hose and throttle
body due to negative pressure in the air cleaner.
POSITIVE CRANKCASE VENTILATION (PCV)
VALVE
PCV valve lifts the plunger according to negative pressure in
the intake manifold to create appropriate ventilation for the
crankcase.
AK704104
AB
Ventilation hose
Breather hose
Flow of blow-by gas (high load area)
Air cleaner
Flow of blow-by gas and clean air (low load area)
Positive crankcase
ventilation valve
AK602324 AC
Plunger
From
rocker
cover
To intake
manifold
Spring