Positive Crankcase Ventilation System - Daihatsu 1997 Terios J100 Service Manual

POSITIVE CRANKCASE VENTILATION SYSTEM

The engine equipped with a sealed type blow-by gas recirculating system in order to prevent blow-by
gases generated inside the crankcase from being released into atmosphere.
When the no blow-by gases is generated in the cylinder, air in the cylinder head cover are ventilated by the
fresh air introduced from up stream of the throttle valve to down stream of the throttle valve through inside
of the cylinder head cover.
At this time, the flow rate of air is regulated by a jet provided at the cylinder head cover, thus stabilizing the
engine idle speed, if engine at the idling.
When the generating amount of the blow-by gases is small, the blow-by gases generated inside the
crankcase flow into the cylinder head cover side through the gas path of the cylinder block, oil in the blow-
by gases is separated by oil separator provided at the cylinder head cover.
Then, the blow-by gases in the cylinder head cover introducing to the cylinders through down stream of the
throttle body to be burnt there again in the cylinders.
At this time, the air flow rate of the blow-by gases is regulated by a jet provided at the cylinder head cover,
thus stabilizing the engine idle speed, if engine at the idling.
When the large amount of the blow-by gases are generated, the blow-by gases are flow into the cylinders
both through the upstream path and downstream path of the throttle valve.
Crankcase gases
Fresh air
Blow-by gases amount is small
Jet
Crankcase gases
Fresh air
Blow-by gases amount is large
EC–3
Jet
JEC00003-00003