Positive crankcase ventilation, fuel evaporation system
Positive crankcase ventilation
Crankcase ventilation prevents the emission of
crankcase gas into the surrounding air. Instead,
these gases are sucked via the inlet manifold
down into the cylinders where they aid the
combustion process.
Crankcase ventilation, inspection
The system is cleaned and the condition of
the rubber hoses and their degree of blockage
should be checked according to the Volvo Ser-
vice Programme. The rubber hoses should be
replaced if they are in poor condition. The ca-
librated nipple should be removed and cleaned.
The flame barrier should be replaced.
Fuel evaporation system
Cars equipped with catalytic converters have
a fuel evaporation system which prevents the
emission of fuel vapour into the air.
The system consists of an equalizing reservoir
in the fuel tank, a "Roll-Over" valve ahead of
the fuel tank and a carbon filter cannister with
integrated vacuum valve in the left wheel-
housing on the wheelarch liner.
The various components are interconnected by
hoses which lead the gases from the fuel tank to
the filter. These gases are stored there until the
engine is started, when they are sucked into the
engine inlet manifold during acceleration (not
at idle speed).
